|Abstracts on Global Climate Change|
Electron tomography of nanoparticle clusters: Implications for atmospheric lifetimes and radiative forcing of soot
van Poppel, LH Friedrich, H Spinsby, J Chung, SH Seinfeld, JH Buseck, PR
GEOPHYSICAL RESEARCH LETTERS 32:24 -
Nanoparticles are ubiquitous in nature. Their large surface areas and consequent chemical reactivity typically result in their aggregation into clusters. Their chemical and physical properties depend on cluster shapes, which are commonly complex and unknown. This is the first application of electron tomography with a transmission electron microscope to quantitatively determine the three-dimensional (3D) shapes, volumes, and surface areas of nanoparticle clusters. We use soot (black carbon, BC) nanoparticles as an example because it is a major contributor to environmental degradation and global climate change. To the extent that our samples are representative, we find that quantitative measurements of soot surface areas and volumes derived from electron tomograms differ from geometrically derived values by, respectively, almost one and two orders of magnitude. Global sensitivity studies suggest that the global burden and direct radiative forcing of fractal BC are only about 60% of the value if it is assumed that BC has a spherical shape.
Global warming is changing the dynamics of Arctic host-parasite systems
Kutz, SJ Hoberg, EP Polley, L Jenkins, EJ
PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES 272:1581 2571-2576
Global climate change is altering the ecology of infectious agents and driving the emergence A disease in people, domestic animals, and wildlife. We present a novel, empirically based, predictive model for the impact of climate warming on development rates and availability of an important parasitic nematode of muskoxen in the Canadian Arctic, a region that is particularly vulnerable to climate change. Using this model, we show that warming in the Arctic may have already radically altered the transmission dynamics of this parasite, escalating infection pressure for muskoxen, and that this trend is expected to continue. This work establishes a foundation for understanding responses to climate change of other host-parasite systems, in the Arctic and globally.
Earlier winter wheat heading dates and warmer spring in the US Great Plains
Hu, Q Weiss, A Feng, S Baenziger, PS
AGRICULTURAL AND FOREST METEOROLOGY 135:1-4 284-290
Phenological change of plants is an indication of local and regional climate change, independent of the instrumentation records and associated bias/error. Although some phenological changes have been identified for native and perennial species and used to infer climate change in various regions of the world, little has been known for changes in agricultural plants/crops. In this study, heading or flowering dates of winter wheat cultivar Kharkof are examined from 70 years of data at six locations in the U.S. Great Plains. Results indicate a consistent trend of earlier heading or flowering dates across all sites, but rates of the trend differ (from 0.8 to 1.8 days per 10-year). Because the heading or flowering date is governed primarily by temperatures, the earlier heading or flowering dates indicate warming temperatures in the spring. Further examinations reveal increase in spring daily minimum temperatures. Findings of this study add a diverse species to the plant community for detecting the “fingerprint” of regional and global climate change. (c) 2006 Elsevier B.V. All rights reserved.
Fish use and size of eelgrass meadows in southeastern Alaska: A baseline for long-term assessment of biotic change
Johnson, SW Thedinga, JF
NORTHWEST SCIENCE 79:2-3 141-155
Eelgrass meadows at six sites in southeastern Alaska were sampled for fish assemblages and mapped to establish a baseline of information for long-term assessment of biotic change. All sites were sampled in spring 2001, 2002, and 2003: four of the sites were also sampled in winter 2003. A total of 44 seine hauls from all sampling periods yielded 58,902 fish comprising 45 species. Fish abundance in spring differed significantly among sites but not among years. The most abundant commercially important or forage fish species captured were chum salmon, Pacific herring. pink salmon, coho salmon, and Pacific sand lance: mean size of each of these species was <= 100 mm FL. For those sites sampled seasonally in 2003, fish were significantly more abundant in spring than in winter. At each site, three different species accounted for most (>= 69%) of the total catch. Size of eelgrass meadows varied annually; maximum percent change in area ranged from -13% to +27%. Eelgrass density ranged from 336 shoots/m(2) to 1,544 shoots/m(2), and dry biomass ranged from 36 g/m(2) to 71 g/m(2). Periodic re-sampling of the eelgrass sites established in this study will allow resource managers to track long-term and large-scale changes in fish communities and habitat that may result from shoreline development or global climate change.
Salt lakes in Australia: present problems and prognosis for the future
HYDROBIOLOGIA 552: 1-15
Australia is a land of salt lakes and despite low human population density, many lakes are adversely impacted by a range of factors. Secondary salinisation is the most pernicious force degrading lakes, especially in south-west Western Australia where up to 30% of the landscape is predicted to be affected. Mining also impinges on many salt lakes in this state, mainly through the dewatering of saline groundwater. Exploitation of groundwater for irrigation caused some lakes in Victoria, Australia, to dry, especially the significant Red Rock Complex. Global climate change will result in new water balances in endorheic lakes, with most having less water, particularly the seasonal lakes of southern Australia. This has already happened in Lake Corangamite, Victoria, but the prime reason is diversion of inflowing floodwater. Consequently, the lake has retreated and become salinised compromising its status as a Ramsar site. Various other lakes suffer from enhanced sedimentation, have introduced biota or their catchments are being disturbed to their detriment. Enlightened management should be able to maintain some important lakes in an acceptable condition, but, for most others, the future is bleak.
Marine research in the Latitudinal Gradient Project along Victoria Land, Antarctica
Berkman, PA Cattaneo-Vietti, R Chiantore, M Howard-Williams, C Cummings, V Kvitek, R
SCIENTIA MARINA 69: Suppl. 2 57-63
This paper describes the conceptual framework of the Latitudinal Gradient Project that is being implemented by the New Zealand, Italian and United States Antarctic programmes along Victoria Land, Antarctica, from 72 degrees S to 86 degrees S. The purpose of this interdisciplinary research project is to assess the dynamics and coupling of marine and terrestrial ecosystems in relation to global climate variability. Preliminary data about the research cruises from the R/V “Italica” and R/V “Tangaroa” along the Victoria Land Coast in 2004 are presented. As a global climate barometer, this research along Victoria Land provides a unique framework for assessing latitudinal shifts in ‘sentinel’ environmental transition zones, where climate changes have an amplified impact on the phases of water.
Global assessment of coral bleaching and required rates of adaptation under climate change
Donner, SD Skirving, WJ Little, CM Oppenheimer, M Hoegh-Guldberg, O
GLOBAL CHANGE BIOLOGY 11:12 2251-2265
Elevated ocean temperatures can cause coral bleaching, the loss of colour from reef-building corals because of a breakdown of the symbiosis with the dinoflagellate Symbiodinium. Recent studies have warned that global climate change could increase the frequency of coral bleaching and threaten the long-term viability of coral reefs. These assertions are based on projecting the coarse output from atmosphere-ocean general circulation models (GCMs) to the local conditions around representative coral reefs. Here, we conduct the first comprehensive global assessment of coral bleaching under climate change by adapting the NOAA Coral Reef Watch bleaching prediction method to the output of a low- and high-climate sensitivity GCM. First, we develop and test algorithms for predicting mass coral bleaching with GCM-resolution sea surface temperatures for thousands of coral reefs, using a global coral reef map and 1985-2002 bleaching prediction data. We then use the algorithms to determine the frequency of coral bleaching and required thermal adaptation by corals and their endosymbionts under two different emissions scenarios. The results indicate that bleaching could become an annual or biannual event for the vast majority of the world’s coral reefs in the next 30-50 years without an increase in thermal tolerance of 0.2-1.0 degrees C per decade. The geographic variability in required thermal adaptation found in each model and emissions scenario suggests that coral reefs in some regions, like Micronesia and western Polynesia, may be particularly vulnerable to climate change. Advances in modelling and monitoring will refine the forecast for individual reefs, but this assessment concludes that the global prognosis is unlikely to change without an accelerated effort to stabilize atmospheric greenhouse gas concentrations.
Consortium for Atlantic Regional Assessment: Information tools for community adaptation to changes in climate or land use
Dempsey, R Fisher, A
RISK ANALYSIS 25:6 1495-1509
To inform local and regional decisions about protecting short-term and long-term quality of life, the Consortium for Atlantic Regional Assessment (CARA) provides data and tools (for the northeastern United States) that can help decisionmakers understand how outcomes of their decisions could be affected by potential changes in both climate and land use. On an interactive, user-friendly website, CARA has amassed data on climate (historical records and future projections for seven global climate models), land cover, and socioeconomic and environmental variables, along with tools to help decisionmakers tailor the data for their own decision types and locations. CARA Advisory Council stakeholders help identify what information and tools stakeholders would find most useful and how to present these: they also provide in-depth feedback for subregion case studies. General lessons include: (1) decisionmakers want detailed local projections for periods short enough to account for extreme events, in contrast to the broader spatial and temporal observations and projections that are available or consistent at a regional level; (2) stakeholders will not use such a website unless it is visually appealing and easy to find the information they want; (3) some stakeholders need background while others want to go immediately to data, and some want maps while others want text or tables. This article also compares what has been learned across case studies of Cape May County, New Jersey, Cape Cod, Massachusetts, and Hampton Roads, Virginia, relating specifically to sea-level rise. Lessons include: (1) groups can be affected differently by physical dangers compared with economic dangers; (2) decisions will differ according to decision makers’ preferences about waiting and risk tolerance; (3) future scenarios and maps can help assess the impacts of dangers to emergency evacuation routes, homes, and infrastructure, and the natural environment; (4) residents’ and decisionmakers’ perceptions are affected by information about potential local impacts from global climate change.
Fossil fuels in the 21st century
AMBIO 34:8 621-627
An overview of the importance of fossil fuels in supplying the energy requirements of the 21st century, their future supply, and the impact of their use on global climate is presented. Current and potential alternative energy sources are considered. It is concluded that even with substantial increases in energy derived from other sources, fossil fuels will remain a major energy source for much Of the 21st century and the sequestration of CO2 will be an increasingly important requirement.
Fates of eroded soil organic carbon: Mississippi basin case study
Smith, SV Sleezer, RO Renwick, WH Buddemeier, R
ECOLOGICAL APPLICATIONS 15:6 1929-1940
We have developed a mass balance analysis of organic carbon (OC) across the five major river subsystems of the Mississippi (MS) Basin (an area of 3.2 X 10(6) km(2)) This largely agricultural landscape undergoes a bulk soil erosion rate of similar to 480 t center dot km(-2)center dot yr(-1) (similar to 1500 x 10(6) t/yr, across the MS Basin), and a,soil organic carbon (SOC) erosion rate of similar to 7 t center dot km(-2 center dot)yr(-1) (similar to 22 x 10(6) t/yr). Erosion translocates upland SOC to alluvial deposits, water impoundments, and the ocean. Soil erosion is generally considered to be a net source of CO2 release to the atmosphere in global budgets. However, our results indicate that SOC erosion and relocation of soil apparently can reduce the net SOC oxidation rate of the original upland SOC while promoting neu replacement of eroded SOC in upland soils that were eroded. Soil erosion at the MS Basin scale is, therefore, a net CO2 sink rather than a source.
Analysing countries’ contribution to climate change: scientific and policy-related choices
den Elzen, M Fuglestvedt, J Hohne, N Trudinger, C Lowe, J Matthews, B Romstad, B de Campos, CP Andronova, N
ENVIRONMENTAL SCIENCE & POLICY 8:6 614-636
This paper evaluates the influence of different policy-related and scientific choices on the calculated regional contributions to global climate change (the “Brazilian Proposal”). Policy-related choices include the time period of emissions, the mix of greenhouse gases and different indicators of climate change impacts. The scientific choices include historical emissions and model representations of the climate system. We generated and compared results of several simple climate models. We find that the relative contributions of different nations to global climate change-from emissions of greenhouse gases alone-are quite robust, despite the varying model complexity and differences in calculated absolute changes. For the default calculations, the average calculated contributions to the global mean surface temperature increase in 2000 are about 40% from OECD, 14% from Eastern Europe and Former Soviet Union, 24% from Asia and 22% from Africa and Latin America. Policy-related choices, such as time period of emissions, climate change indicator and gas mix generally have larger influence on the results than scientific choices. More specifically, choosing a later attribution start date (1990 instead of 1890) for historical emissions, decreases the contributions of regions that started emitting early, such as the OECD countries by 6 percentage points, whereas it increases the contribution of late emitters such as Asia by 8 percentage points. However, only including the fossil CO, emissions instead of the emissions of all Kyoto gases (fossil and land use change), increases the OECD contributions by 21 percentage points and decreases the contribution of Asia by 14 percentage points. (c) 2005 Elsevier Ltd. All rights reserved.
Seductive simulations? Uncertainty distribution around climate models
SOCIAL STUDIES OF SCIENCE 35:6 895-922
This paper discusses the distribution of certainty around General Circulation Models (GCMs) - computer models used to project possible global climatic changes due to human emissions of greenhouse gases. It examines the trope of distance underpinning Donald MacKenzie’s concept of ‘certainty trough’, and calls for a more multi-dimensional and dynamic conceptualization of how uncertainty is distributed around technology. The certainty trough describes the level of certainty attached to particular technoscientific constructions as distance increases from the site of knowledge production, and proposes that producers of a given technology and its products are the best judges of their accuracy. Processes and dynamics associated with GCM modeling challenge the simplicity of the certainty trough diagram, mainly because of difficulties with distinguishing between knowledge producers and users, and because GCMs involve multiple sites of production. This case study also challenges the assumption that knowledge producers always are the best judges of the accuracy of their models. Drawing on participant observation and interviews with climate modelers and the atmospheric scientists with whom they interact, the study discusses how modelers, and to some extent knowledge producers in general, are sometimes less able than some users to identify shortcomings of their models.
American risk perceptions: Is climate change dangerous?
RISK ANALYSIS 25:6 1433-1442
Public risk perceptions can fundamentally compel or constrain political, economic, and social action to address particular risks. Public support or opposition to climate policies (e.g., treaties, regulations, taxes, subsidies) will be greatly influenced by public perceptions of the risks and dangers posed by global climate change. This article describes results from a national study (2003) that examined the risk perceptions and connotative meanings of global warming in the American mind and found that Americans perceived climate change as a moderate risk that will predominantly impact geographically and temporally distant people and places. This research also identified several distinct interpretive communities, including naysayers and alarmists, with widely divergent perceptions of climate change risks. Thus, “dangerous” climate change is a concept contested not only among scientists and policymakers, but among the American public as well.
A conceptual model of ecological interactions in the mangrove estuaries of the Florida Everglades
Davis, SM Childers, DL Lorenz, JJ Wanless, HR Hopkins, TE
WETLANDS 25:4 832-842
A brackish water ecotone of coastal bays and lakes, mangrove forests, salt marshes, tidal creeks, and upland hammocks separates Florida Bay, Biscayne Bay, and the Gulf of Mexico from the freshwater Everglades. The Everglades mangrove estuaries are characterized by salinity gradients that vary spatially with topography and vary seasonally and inter-annually with rainfall, tide, and freshwater flow from the Everglades. Because of their location at the lower end of the Everglades drainage basin, Everglades mangrove estuaries have been affected by upstream water management practices that have altered the freshwater heads and flows and that affect salinity gradients. Additionally, interannual variation in precipitation patterns, particularly those caused to El Nino events, control freshwater inputs and salinity dynamics in these estuaries. Two major external drivers on this system are water management activities and global climate change. These drivers lead to two major ecosystem stressors: reduced freshwater flow volume and duration, and sea-level rise. Major ecological attributes include mangrove forest production, soil accretion, and resilience; coastal lake submerged aquatic vegetation; resident mangrove fish populations; wood stork (Mycteria americana) and roseate spoonbill (Platelea ajaja) nesting colonies; and estuarine crocodilian populations. Causal linkages between stressors and attributes include coastal transgression, hydroperiods, salinity gradients, and the “white zone” freshwater/estuarine interface. The functional estuary and its ecological attributes, as influenced by sea level and freshwater flow, must be viewed as spatially dynamic, with a possible near-term balancing of transgression but ultimately a long-term continuation of inland movement. Regardless of the spatio-temporal timing of this transgression, a salinity gradient supportive of ecologically functional Everglades mangrove estuaries will be required to maintain the integrity of the South Florida ecosystem.
Fine-scale predictions of distributions of Chagas disease vectors in the state of Guanajuato, Mexico
Lopez-Cardenas, J Bravo, FEG Schettino, PMS Solorzano, JCG Barba, ER Mendez, JM Sanchez-Cordero, V Peterson, AT Ramsey, JM
JOURNAL OF MEDICAL ENTOMOLOGY 42:6 1068-1081
One of the most daunting challenges for Chagas disease surveillance and control in Mexico is the lack of community level data on vector distributions. Although many states now have assembled representative domestic triatomine collections, only two triatomine specimens bad been collected and reported previously from the state of Guanajuato. Field personnel from the state’s Secretaria de Salud conducted health promotion activities in 43 of the 46 counties in the state and received donations of a total of 2,522 triatomine specimens between 1998 and 2002. All specimens were identified, and live insects examined for Trypanosoma cruzi. In an effort to develop fine-scale distributional data for Guanajuato, collection localities were georeferenced and ecological niches were modeled for each species by using evolutionary-computing approaches. Five species were collected: Triatoma mexicana (Herrich-Schaeffer), Triatoma longipennis (Usinger), Triatoma pallidipennis (Stal), Triatoma barberi (Usinger), and Triatoma dimidiata (Latreille) from 201 communities located at elevations of 870 - 2,200 m. Based on collection success, T mexicana had the broadest dispersion, although niche mapping indicates that T barberi represents the greatest risk for transmission of Chagas disease in the state. T dimidiata was represented in collections by a single adult collected from one village outside the predicted area for all species. For humans, In estimated 3,755,380 individuals are at risk for vector transmission in the state, with an incidence of 3,500 new cases per year; overall seroprevalences of 2.6% indicate that 97,640 individuals are infected with T cruzi at present, including 29,300 chronic cases.
Fine-scale processes regulate the response of extreme events to global climate change
Diffenbaugh, NS Pal, JS Trapp, RJ Giorgi, F
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 102:44 15774-15778
We find that extreme temperature and precipitation events are likely to respond substantially to anthropogenically enhanced greenhouse forcing and that fine-scale climate system modifiers are likely to play a critical role in the net response. At present, such events impact a wide variety of natural and human systems, and future changes in their frequency and/or magnitude could have dramatic ecological, economic, and sociological consequences. Our results indicate that fine-scale snow albedo effects influence the response of both hot and cold events and that peak increases in extreme hot events are amplified by surface moisture feedbacks. Likewise, we find that extreme precipitation is enhanced on the lee side of rain shadows and over coastal areas dominated by convective precipitation. We project substantial, spatially heterogeneous increases in both hot and wet events over the contiguous United States by the end of the next century, suggesting that consideration of fine-scale processes is critical for accurate assessment of local- and regional-scale vulnerability to climate change.
Trace metal analysis in arctic aerosols by an inductively coupled plasma-time of flight-mass spectrometer combined with an inductively heated vaporizer
Ludke, C Skole, J Taubner, K Kriews, M
SPECTROCHIMICA ACTA PART B-ATOMIC SPECTROSCOPY 60:11 1412-1422
Two newly developed instruments were combined to analyze the trace metal content in size separated arctic aerosols during the measurement campaign ASTAR 2004 (Arctic Study of Tropospheric Aerosols, Clouds and Radiation 2004) at Spitsbergen in May-June 2004. The aim of this extensive aerosol measurement campaign was to obtain a database for model-calculations of arctic aerosol, which play an important role in the global climate change. The ASTAR project was centered on two aircraft measurement campaigns, scheduled from 2004 to 2005, addressing both aerosol and cloud measurements, combined with ground-based and satellite observations. In the present paper one example for the analysis of ground-based aerosol particles is described. The sampling of aerosol particles was performed in a well-known manner by impaction of the particles on cleaned graphite targets. By means of a cascade impactor eight size classes between 0.35 and 16.6 mu m aerodynamic diameters were separated. To analyze the metal content in the aerosol particles the targets were rapidly heated up to 2700 degrees C in an inductively heated vaporizer system (IHVS). An argon flow transports the vaporized sample material into the inductively coupled plasma (ICP) used as ionization source for the time of flight-mass spectrometer (TOF-MS). The simultaneous extraction of the ions from the plasma, as realized in the TOF instrument, allows to obtain the full mass spectrum of the sample during the vaporization pulse without any limitation in the number of elements detected. With optimized experimental parameters the element content in arctic aerosol particles was determined in a mass range between Li-7 and Bi-209. Comparing the size distribution of the elemental content of the aerosol particles, two different meteorological situations were verified. For calibration acidified reference solutions were placed on the cleaned target inside the IHVS. The limits of detection (LOD) for the element mass on the target range between 2 and 200 pg for the elements studied, except Na, Mg, and Cr, which are influenced by high background. (c) 2005 Elsevier B.V. All rights reserved.
Global climate change and the equity-efficiency puzzle
Manne, AS Stephan, G
ENERGY 30:14 2525-2536
There is a broad consensus that the costs of abatement of global climate change can be reduced efficiently through the assignment of quota rights and through international trade in these rights. There is, however, no consensus on whether the initial assignment of emissions permits can affect the Pareto-optimal global level of abatement. This paper provides some insight into the equity-efficiency puzzle. Qualitative results are obtained from a small-scale model; then quantitative evidence of separability is obtained from MERGE, a multiregion integrated assessment model. It is shown that if all the costs of climate change can be expressed in terms of GDP losses, Pareto-efficient abatement strategies are independent of the initial allocation of emissions rights. This is the case sometimes described as ‘market damages’. If, however, different regions assign different values to nonmarket damages such as species losses, different sharing rules may affect the Pareto-optimal level of greenhouse gas abatement. Separability may then be demonstrated only in specific cases (e.g. identical welfare functions or quasi-linearity of preferences or small shares of wealth devoted to abatement). (c) 2004 Elsevier Ltd. All rights reserved.
From regional to global dynamics structure of the climatic proxy
Wan, SQ Feng, GL Dong, WJ Li, JP
ACTA PHYSICA SINICA 54:11 5487-5493
Global change science is a new research domain nowadays, and one of the most important studies of which is the climate change,to which great attention is paid by all governments in world. It is mainly based on the climatic proxy that we can study the past climate change. Although many achievements have been obtained, majority of the results are limited to the external characteristics of the proxy due to lagged analysis methods. For example, we judge if the climate is flood/drought or cold/warm through linear trend of the time series, however, we do not know whether it is a natural variation or the result of external forces, the mechanism is not uncovered. Because complexity of the open global climate system, there are different characteristics among the climatic proxies from different region of the world, from which it is difficult to reveal the intrinsic general principles i.e. the globality. For the further study on the past climate change, especially to reveal the rules of the global climate change in past 2000a and predict future climate change, a new method making use of the dynamical lag correlation exponent (named Q index in the text), a dynamics exponent based on the phase-space reconstruction, is introduced in this paper, which can effectively discern the similarities or differences between the dynamics of the two series. With Q index, we analyze the dynamics structure of some typical climatic proxies. The results show that the dynamics of climatic proxies are almost similar, and the regional climate keeps the same change with the global. In other words, regional climate is controlled by the global climate change. Besides, there are two dynamics jump periods (namely 700-900a and 1300-1700a) in past 2000a of the climate system, which may correspond to the periods of the medieval warm period and the little ice age, respectively.
Flood risk, uncertainty, and scientific information for decision making - Lessons from an interdisciplinary project
Morss, RE Wilhelmi, OV Downton, MW Gruntfest, E
BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY 86:11 1593-+
The magnitude of flood damage in the United States, combined with the uncertainty in current estimates of flood risk, suggest that society could benefit from improved scientific information about flood risk. To help address this perceived need, a group of researchers initiated an interdisciplinary study of climate variability, scientific uncertainty, and hydrometeorological information for flood-risk decision making, focused on Colorado’s Rocky Mountain Front Range urban corridor. We began by investigating scientific research directions that were likely to benefit flood-risk estimation and management, through consultation with climatologists, hydrologists, engineers, and planners. In doing so, we identified several challenges involved in generating new scientific information to aid flood management in the presence of significant scientific and societal uncertainty. This essay presents lessons learned from this study, along with our observations on the complex interactions among scientific information, uncertainty, and societal decision making. It closes by proposing a modification to the “end to end” approach to conducting societally relevant scientific research. Although we illustrate points using examples from flood management, the concepts may be applicable to other arenas, such as global climate change.
Refugial forests of the southern Appalachians: photosynthesis and survival in current-year Abies fraseri seedlings
Johnson, DM Smith, WK
TREE PHYSIOLOGY 25:11 1379-1387
Fraser fir (Abies fraseri (Pursh) Poiret) is an endemic, high-elevation conifer confined to six relict mountain-top communities in the southern Appalachian Mountains, USA. High adult mortality has occurred over the past 50 years, possibly the result of an introduced insect (Adelges piceae Ratzeburg), air pollution, or both. Knowledge of the mechanisms of and limitations to seedling establishment may allow reestablisment and perpetuation of this unique community type, notwithstanding global climate change. We monitored seedling emergence and mortality in relation to photosynthetic performance and water relations in microsites differing in canopy openness (sunlight exposure) over the summer of 2004. Abundance of cotyledonous seedlings in early summer was 2.3 times greater (849 versus 366 seedlings m(-2)) in microsites with lower sky exposure (greater canopy closure) than in microsites with greater sky exposure (greater canopy openness). In contrast, late-season abundance and survival were greater in areas beneath more open canopies than in areas beneath less open canopies (3.3 times and 11.7 times greater, respectively). However, newly emerged seedling survival in a completely open site (no overhead canopy) was zero, despite an initial density of 124 seedlings m(-2). Seedling water status was similar in open- and closed-canopy sites (-0.52 and -0.74 MPa, respectively). Photosynthetic carbon gain was higher in newly emerged seedlings at open canopy than at closed canopy sites, especially during early morning. Based on photosynthetic light response curves and measured sunlight regimes, seedlings in open canopy sites were estimated to assimilate 3.3-4.5 times more carbon than seedlings at closed sites. Reductions in carbon gain of closed-site seedlings, primarily a result of limited sunlight, corresponded to substantial increases in seedling mortality (98 versus 79% in open canopy sites). Thus, sunlight exposure, which reflects overstory canopy structure, appears to be an important factor influencing newly emerged seedling survival and distribution.
Direct constraints on Antarctic Peninsula Ice Sheet grounding events between 5.12 and 7.94 Ma
Bart, PJ Egan, D Warny, SA
JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE 110:F4 -
How has the Antarctic Ice Sheet responded to or influenced global climate change? This simple question has been difficult to address because the long-term records of the ice sheet’s fluctuations are poorly constrained with geologic data from Antarctica. Thus studies to date have not convincingly established how specific Antarctic Ice Sheet events correlate with climatic, eustatic, or other phenomena known from low-latitude and deep-sea records. This study focused on documenting the direct record of ice sheet advance and retreat to the Antarctic Peninsula’s shelf edge. On the peninsula’s outer shelf, seismic reflectors interpreted to be subglacial unconformities were correlated with published results from Ocean Drilling Program Leg 178. Lithologic and chronologic control at two drill sites provided ground truth for the seismic interpretation and the timing of the Antarctic Peninsula Ice Sheet grounding events. This synthesis showed that grounded ice advanced to the shelf edge on at least 12 occasions between 5.12 and 7.94 Ma.
Variation of karst spring discharge in the recent five decades as an indicator of global climate change: A case study at Shanxi, northern China
Guo, QH Wang, YX Ma, T Li, LX
SCIENCE IN CHINA SERIES D-EARTH SCIENCES 48:11 2001-2010
Karst in Shanxi Province is representative of that in northern China, and karst water systems discharge in the form of springs that are among the most important sources for local water supply. Since the 1950s, attenuation has been the major trend of discharge variation of most karst springs at Shanxi. Based on the case study of 7 karst springs including Niangziguan, Xin’an, Guozhuang, Shentou, Jinci, Lancun, and Hongshan springs, the discharge variation process of karst springs was divided into natural fluctuation phase and anthropogenic impact phase. Discharge attenuation of the 7 karst springs was controlled mainly by climate and human activities, with their contributions being respectively about 60% and 40%. According to the difference of the effect of climate and human activities for each spring, attenuation modes of spring discharge fall into three types: natural process dominated attenuation type, exploitation induced process dominated attenuation type, and mixed attenuation type. The total restored discharge variation of 7 karst springs matched well with the global air temperature change in 1956-2000, clearly indicating the trend of global warming and aridity in the last several decades, and the analysis of discharge variation processes of karst springs can be used as a new tool for global change studies.
A model to predict climate-change impact on fish catch in the world oceans
Biswas, BK Svirezhev, YA Bala, BK
IEEE TRANSACTIONS ON SYSTEMS MAN AND CYBERNETICS PART A-SYSTEMS AND HUMANS 35:6 773-783
Water temperature plays a very important role in fish production. The assessment of the impact of water-temperature changes on fish catches in world fishery is essential for the sustainable management of world fishery resources. Fish catch includes different species, but using information analysis, it is shown that total fish catch can be used without significant loss of information about the dynamic properties of the system. A new method for the forecasting of the fish catch of the major fishing areas in the world’s oceans under global climate change (temperature) has been developed. This method predicts the tendency (increase or decrease) for fish catch, with quantitative predictor’s power, if the temperature is known. This method has been applied to the Indian Ocean to assess the climate-change impact on fish catch. Based on the temperatures predicted using the CLIMate-BiospheRE model for the years 2000-2100, a decrease of fish catch in the Indian Ocean, with the confidence of the predictor’s power at >= 90%, has been predicted.
Soil carbon sequestration for sustaining agricultural production and improving the environment with particular reference to Brazil
JOURNAL OF SUSTAINABLE AGRICULTURE 26:4 23-42
Agricultural ecosystems generally contain less soil organic carbon (SOC) pool than their potential capacity because of the low return and high rate of mineralization of biosolids, and severe losses due to accelerated erosion and leaching. Conversion of natural to agricultural ecosystems usually causes depletion of 50 to 75 percent of the antecedent SOC pool, thereby creating a potential sink capacity of as much as 35 to 40 Mg C/ha. The depletion of SOC pool leads to decline in soil quality and resilience with attendant reduction in biomass productivity, decreased capacity to degrade and filter pollutants, increased risks of soil degradation by erosion and other processes, and increase in emission of greenhouse gases (GHGs). The magnitude of depletion of SOC pool is greater for soils of the tropics than temperate regions, and for farms which are resource-based and managed with low-input than those managed with science-based and judicious off-farm inputs. The SOC sequestration, increasing SOC pool through conversion to an appropriate land use and adoption of recommended management practices (RMPs), can reverse soil degradation trends, improve soil quality and resilience, increase biomass production and decrease emission of GHGs. A strong link exists between the labile fraction of SOC pool and soil biodiversitythe activity and species diversity of soil fauna (micro, meso and macro) and micro-organisms. Soil biodiversity is usually higher under pastures and planted fallow systems than under crops, and is likely to increase with adoption of conservation tillage and mulch farming, integrated nutrient management and manuring, mixed farming systems and integrated pest management (IPM) techniques. The gross rates of SOC sequestration through adoption of RMPs range from 400 to 800 kg/ha/y for cool and humid regions and 100 to 200 kg/ha/y for dry and warm climates. The potential of soil C sequestration in Brazil is estimated at about 50 Tg C/y. In addition, 60 Tg C/y emitted by erosion-induced mineralization can also be avoided through effective erosion control measures.
Climate changes and tree phylogeography in the Mediterranean
Petit, RJ Hampe, A Cheddadi, R
TAXON 54:4 877-885
The Mediterranean Basin is expected to be more strongly affected by ongoing global climate change than most other regions of the earth. Given the magnitude of forecasted trends, there are great concerns for the particularly rich biodiversity found in the region. Studies of the consequences of past climate shifts on biodiversity represent one of the best sources of data to validate models of the ecological and evolutionary consequences of future changes. Here we review recent findings from palaeoecology, phylogeography and climate change research to (1) explore possible antecedents of the predicted climate warming in the younger geological history of the Mediterranean Basin, (2) assess how tree populations have reacted to them, and (3) evaluate the significance of the evolutionary heritage that is at stake. A major question of our retrospective approach is whether Quaternary tree extinctions took place primarily during glacial or during interglacial episodes. Available data are scanty and somewhat conflicting. In contrast, abundant phylogeographic evidence clearly indicates that the bulk of genetic diversity in European temperate tree species is almost invariably located in the southernmost part of their range. Long-term persistence of isolated populations have been common phenomena in the Mediterranean, to the point that the current genetic structure in this area probably often reflects population divergence that pre-dates the onset of the Mediterranean climate in the Pliocene. In particular, Tertiary migrations into the Mediterranean of tree taxa originating from Asia seem to have left their footprints in the current genetic structure in these slowly evolving organisms. Moreover, phylogeographic studies point to heterogeneous rates of molecular evolution across lineages that are inversely related with their stability. We conclude that relict tree populations in the Mediterranean Basin represent an evolutionary heritage of disproportionate significance for the conservation of European plant biodiversity.
Photoreactivation in two freshwater ciliates: differential responses to variations in UV-B flux and temperature
Sanders, RW Macaluso, AL Sardina, TJ Mitchell, DL
AQUATIC MICROBIAL ECOLOGY 40:3 283-292
The effects of UV-B radiation on 2 ciliate species (Glaucoma sp. and Cyclidium sp.) from a clear oligotrophic lake were examined under laboratory conditions with and without photoreactivating radiation (PRR: UV-A and visible light). Glaucoma sp. was exposed to 3 UV-B intensities at 4 temperatures to simulate a range of environmentally relevant conditions. Population growth of Glaucoma sp. declined with increasing levels of UV-B exposure in treatments receiving PRR; blocking PRR generally resulted in 100% mortality. Occurrence of cyclobutane pyrimidine dimers (CPDs [mb DNA](-1)) was significantly reduced in Glaucoma sp. receiving PRR relative to those without PRR. These data indicate that photoenzymatic repair is a major component of UV-B tolerance in Glaucoma. At UV-B levels that Glaucoma sp. tolerated, Cyclidium sp. suffered 100% mortality and accumulated a similar level of CPDs whether or not PRR was blocked. Incubation of the 2 ciliates under UV-transparent and UV-blocking acrylics in the oligotrophic lake confirmed their relative sensitivities to UV radiation (UVR). Photoenzymatic repair in Glaucoma sp. was more efficient at 20 degrees C than at 10, 15 and 25 degrees C. The temperature-dependent nature of photoenzymatic repair underscores the need to consider the interactive effects of temperature and UVR on biota, particularly in the face of global climate change and rising incident UVR due to ozone depletion.
Paleoceanographic records and sea ice extension history on the slope of the northern Bering Sea over the last 100 ka BP
Wang, RJ Li, X Xiao, WS Xia, PF Chen, RH
ACTA OCEANOLOGICA SINICA 24:6 117-126
Quantitative analytic results of the biogenic components in Core B2-9 from the northern Bering Sea slope indicate that the coarse fraction and opal content, serving as proxies of surface productivity, have increased stepwise since the marine isotope stage(MIS)5.3, reflecting periodic enhancement in surface productivity. The surface productivity attained its highest level during the Holocene, followed by MIS 3.2 to 2 and then MIS 5.3 to 3.3 with a lowest level. High total organic carbon(TOC) contents, together with high C/N ratios, which stand mostly between 7 and 20, show that the TOC was deposited from mixing sources. Therefore,one has to be cautious to use TOC as a proxy of surface productivity. The high TOC and C/N ratio during MIS 5.1, 3.3 to 3.2 and the Holocene reflect that the terrigenous organic matter input increased during interglacial periods. Increases in the fine- and silt-grained terrigenous components from MIS 5.3 to the middle Holocene imply that with the cooling climate, sea ice on the Bering Sea slope extended continuously. Ice-rafted and charcoal detritus increased during glacial, interstadial and the last deglaciation periods and decreased during interglacial periods, suggesting that sea ice on the slope increased and melted, respectively, during glacial and interglacial periods. The extension of sea ice during glacial periods,which was linked with the climate over the North American Continent, responded to global climate change during late Quaternary glacial and interglacial cycles.
Derivation of quantitative management objectives for annual instream water temperatures in the Sabie River using a biological index
Rivers-Moore, NA Jewitt, GPW Weeks, DC
WATER SA 31:4 473-481
Adaptive management of river systems assumes uncertainty and makes provision for system variability. Inherent within this management approach is that perceived limits of ‘acceptable’ system variability are regarded not only as testable hypotheses, but also as playing a central role in maintaining biodiversity. While the Kruger National Park currently functions as a flagship conservation area in South Africa, projected increases in air temperatures as a consequence of global climate change present challenges in conserving this biodiversity inside the established land boundaries. Within the rivers of the Kruger National Park, a management goal of maintaining biodiversity requires a clearer understanding of system variability. One component of this is water temperature, an important water quality parameter defining the distribution patterns of aquatic organisms. In this study, Chiloglanis anoterus Crass (1960) (Pisces: Mochokidae) was selected as a biological indicator of changes in annual water temperatures within the Sabie River in the southern Kruger National Park. Relative abundances of C. anoterus were determined using standard electro-fishing surveys. The presence or absence of C. anoterus was linked to cumulative annual heat units using a logistic regression model, and a critical annual cumulative water temperature threshold estimated. A correlative relationship between this temperature threshold and a biological index using a C. anoterus condition factor provides river ecologists with a tool to assess ecologically significant warming trends in Sabie River water temperatures. A similar approach could be applied with relative ease to other Southern African river systems. Further testing of this hypothesis is suggested, as part of the adaptive management cycle.
Possible impact of urbanization on the thermal climate of some large cities in Mexico
ATMOSFERA 18:4 249-252
Urbanization has been the dominant demographic trend during the second half of the 20th century in Mexico. In 2000 there were 69 cities with more than 100,000 inhabitants of which 9 of them exceeded one million population, totalizing 53.4 million. Using time series of mean monthly temperature for about a dozen available stations, this paper sets out to examine temperature changes occurring during the late 20th century. Since it is well established that urban warming is mainly a nocturnal phenomenon minimum temperature series were selected after a test for homogeneity. Trend analysis was applied to the minimum temperature series and a linear regression coefficient was obtained. Tests of significance were performed. Most of the positive trends proved to be significant (>90%). Although temperature trend variability amongst the individual cities was large (from 0.02 degrees C/decade to 0.74 degrees C/decade) average temperature increase in large (>= 10(6) inhabitants) cities was (0.57 degrees C/decade) considerably higher than that corresponding to medium size urban centers where on the average temperature increase was 0.37 degrees C/decade. These temperature increases express not only the urbanization effect but also that due to global climate change (of the order of 0.07 degrees C/decade) and natural variability. In concluding it may be said that increasing urbanization in Mexico has originated a positive trend in urban temperatures which has implications for human comfort and health.
Alterations in the production and concentration of selected alkaloids as a function of rising atmospheric carbon dioxide and air temperature: implications for ethno-pharmacology
Ziska, LH Emche, SD Johnson, EL George, K Reed, DR Sicher, RC
GLOBAL CHANGE BIOLOGY 11:10 1798-1807
The influence of recent and projected changes in atmospheric carbon dioxide concentration [CO2] with and without concurrent increases in air temperature was determined with respect to growth characteristics and production of secondary compounds (alkaloids) in tobacco (Nicotiana tabacum L.) and jimson weed (Datura stramonium L.) over a ca. 50-day period. Rising [CO2] above that present at the beginning of the 20th century resulted in consistent, significant increases in leaf area, and above ground dry weight (both species), but decreased leaf area ratio (LAR) and specific leaf area (SLA) in jimson weed. Increased temperature resulted in earlier development and increased leaf area for both species, but increases in above ground final dry weight were observed only for jimson weed. The secondary compounds evaluated included the alkaloids, nicotine, atropine and scopolamine. These compounds are generally recognized as having impacts with respect to herbivory as well as human physiology. Rising [CO2] reduced the concentration of nicotine in tobacco; but had no effect on atropine, and increased the concentration of scopolamine in jimson weed. However, because of the stimulatory effect of [CO2] on growth, the amount of all three secondary compounds increased on a per plant basis in both species. Temperature per se had no effect on nicotine or scopolamine concentration, but significantly increased the concentration and amounts of atropine per plant. Overall, the underlying mechanism of CO2 induced changes in secondary compounds remains unclear; however, these data suggest that the increase in [CO2] and temperature associated with global climate change may have significant effects not only with respect to herbivory, but on the production of secondary compounds of pharmacological impact.
Influence of land use on plant community composition and diversity in Highland Sourveld grassland in the southern Drakensberg, South Africa
JOURNAL OF APPLIED ECOLOGY 42:5 975-988
1. Biodiversity conservation of grasslands in the face of transformation and global climate change will depend mainly on rangelands because of insufficient conservation areas in regions suited to agriculture. Transformed vegetation (pastures, crops and plantations) is not expected to conserve much biodiversity. This study examined the impact of land use on the plant diversity and community composition of the southern Drakensberg grasslands in South Africa, which are threatened with complete transformation to pastures, crops and plantations. 2. The main land uses in this high rainfall region are: ranching or dairy production under private tenure using indigenous grassland, pastures (Eragrostis curvula, kikuyu and ryegrass) and maize; plantation forestry; communal tenure (maize and rangelands); and conservation. 3. Plant diversity and composition were assessed using Whittaker plots. Transformed cover types were depauperate in species and ranged from kikuyu (1.4 species m(-2)) and ryegrass (2.9), to pine plantation (3.1), E. curvula pasture (3.1), commercial maize (3.2) and communal maize (7.8). With the exception of pine plantations, these communities supported mostly exotic (50 of 70 species) or ruderal indigenous species and made little contribution to plant species conservation. Abandoned communal cropland reverted to an indigenous grassland almost devoid of exotic species within c. 20 years. 4. It was predicted that frequently cultivated sites (maize and ryegrass) would support less diversity than long-lived pastures (kikuyu and E. curvula). This was contradicted by the relatively high species diversity of communal maize fields, which was attributed to a lack of herbicides, and the depauperate communities of kikuyu and of E. curvula pasture, which were attributed, respectively, to a dense growth form and a severe mowing regime. 5. Pine plantations harboured fourfold more indigenous species per plot (27) than other transformed types. Species were mostly shade-tolerant grassland relics that had persisted for 12 years since planting, and some forest colonizers. Indigenous species were unlikely to be maintained because of aggressive invasion by the exotic Rubus cuneifolius and severe disturbance associated with tree harvest and replanting. 6. The richness of indigenous grasslands was expected to differ in response to grazing pressure but they differed only in composition. Grasslands were dominated by grasses, despite the richness of herbaceous species. The dominance of Themeda triandra was reduced under livestock grazing in favour of more grazing-tolerant species. Exotic species were inconspicuous except for the dicotyledon Richardia brasiliensis, a subdominant under communal grazing. 7. Southern Drakensberg grasslands are probably now stocked with livestock six- to 35-fold higher than during pre-settlement times. A grassland protected for c. 50 years supported twofold greater richness (101 species plot(-1)) than grazed grasslands, suggesting that a 150-year history of increased mammalian grazing had already reduced plant diversity. 8. Synthesis and applications. Land acquisition is costly, thus conservation of plant diversity in the southern Drakensberg requires a policy that inhibits transformation of rangelands. This can be achieved by enhancing their economic viability without changing the vegetation composition. Their inherent value must be recognized, such as for water production. The viability of commercial ranches can be improved by increasing their size. Conservation efforts need to be focused on plant taxa that only occur on unprotected rangelands.
Changes of anti-oxidative enzymes and MDA content under soil water deficits among 10 wheat (Triticum aestivum L.) genotypes at maturation stage
Shao, HB Liang, ZS Shao, MA
COLLOIDS AND SURFACES B-BIOINTERFACES 45:1 7-13
Drought is a world-spread problem seriously influencing grain production and quality, the loss of which is the total for other natural disasters, with increasing global climate change making the situation more serious. Wheat is the staple food for more than 35% of world population, so wheat anti-drought physiology study is of importance to wheat production and biological breeding for the sake of coping with abiotic and biotic conditions. Much research is involved in this hot topic, but the pace of progress is not so large because of drought resistance being a multiple-gene-control quantitative character and wheat genome being larger (16,000 Mb). On the other hand, stress adaptive mechanisms are quite different, with stress degree, time course, materials, soil quality status and experimental plots, thus increasing the complexity of the issue in question. Additionally, a little study is related to the whole life circle of wheat, which cannot provide a comprehensive understanding of its anti-drought machinery. We selected 10 kinds of wheat genotypes as materials, which have potential to be applied in practice, and measured change of relative physiological indices through wheat whole growing-developmental circle (i.e. seedling, tillering and maturing). Here, we reported the anti-oxidative results of maturation stage (the results of seedling and tillering stage have been published) in terms of activities of POD, SOD, CAT and MDA content as follows: (1) 10 wheat genotypes can be grouped into three kinds (A-C, respectively) according to their changing trend of the measured indices; (2) A group performed better resistance drought under the condition of treatment level 1 (appropriate level), whose activities of anti-oxidative enzymes (POD, SOD, CAT) were higher and MDA lower; (3) B group exhibited stronger anti-drought under treatment level 2 (light-stress level), whose activities of anti-oxidative enzymes were higher and MDA lower; (4) C group expressed anti-drought to some extent under treatment level 3 (serious-stress level), whose activities of anti-oxidative enzymes were stronger, MDA lower; (5) these results demonstrated that different wheat genotypes have different physiological mechanisms to adapt themselves to changing drought stress, whose molecular basis is discrete gene expression profiling (transcriptom); (6) our results also showed that the concept and method accepted and adopted by most researchers [T.C. Hsiao, Plant response to water stress, Ann. Rev. Plant Physiol. 24 (1973) 519-570], that 75% FC is a proper supply for higher plants, was doubted, because this level could not reflect the true suitable level of different wheat genotypes. The study in this respect is the key to wheat anti-drought and biological-saving water agriculture; (7) our research can provide insights into physiological mechanisms of crop anti-drought and direct practical materials for wheat anti-drought breeding; (8) the physiological study of wheat is more urgent up-to-date and molecular aspects are needed, but cannot substitute this important part. The combination of both is an important strategy and a key and (9) POD, SOD and CAT activities and MDA content of different wheat genotypes had quite different changing trend at different stages and under different soil water stress conditions, which was linked with their origin of cultivation and individual soil water threshold. (c) 2005 Elsevier B.V. All rights reserved.
Growing typhoon influence on east Asia
Wu, LG Wang, B Geng, SQ
GEOPHYSICAL RESEARCH LETTERS 32:18 -
Numerical model studies have suggested that the ongoing global climate change will likely affect tropical cyclone activity. Since the global warming has been underway, it is meaningful to ask: Are there evidences of observed changes in tropical cyclone activity? Using best-track data from 1965 to 2003, we show for the first time that over the past four decades the two prevailing typhoon tracks in the western North Pacific (WNP) have shifted westward significantly; thus the subtropical East Asia has experienced increasing typhoon influence; but the typhoon influence over the South China Sea has considerably decreased. Our trajectory model simulation indicates that the long-term shifts in the typhoon tracks result primarily from the changes in the mean translation velocity of typhoons or the large-scale steering flow, which is associated with the westward expansion and strengthening of the WNP subtropical high.
Changes in tropical cyclone number, duration, and intensity in a warming environment
Webster, PJ Holland, GJ Curry, JA Chang, HR
SCIENCE 309:5742 1844-1846
We examined the number of tropical cyclones and cyclone days as well as tropical cyclone intensity over the past 35 years, in an environment of increasing sea surface temperature. A large increase was seen in the number and proportion of hurricanes reaching categories 4 and 5. The largest increase occurred in the North Pacific, Indian, and Southwest Pacific Oceans, and the smallest percentage increase occurred in the North Atlantic Ocean. These increases have taken place while the number of cyclones and cyclone days has decreased in all basins except the North Atlantic during the past decade.
The contribution of sulfuric acid and non-volatile compounds on the growth of freshly formed atmospheric aerosols
Wehner, B Petaja, T Boy, M Engler, C Birmili, W Tuch, T Wiedensohler, A Kulmala, M
GEOPHYSICAL RESEARCH LETTERS 32:17 -
The formation of atmospheric aerosol particles ( homogeneous nucleation, forming of stable clusters similar to 1 nm in size), their subsequent growth to detectable sizes (> 3 nm), and to the size of cloud condensation nuclei, remains one of the least understood atmospheric processes upon which global climate change critically depends. However, a quantitative model explanation for the growth of freshly formed aerosols has been missing. In this study, we present observations explaining the nucleation mode ( 3 - 25 nm) growth. Aerosol particles typically grow from 3 nm to 60 - 70 nm during a day, while their non-volatile cores grow by 10 - 20 nm as well. The total particle growth rate is 2 - 8 nm/h while the non-volatile core material can explain 20 - 40%. According to our results, sulfuric acid can explain the remainder of the growth, until the particle diameter is around 10 - 20 nm. After that secondary organic compounds significantly take part in growth process.
The role of plants and land management in sequestering soil carbon in temperate arable and grassland ecosystems
Rees, RM Bingham, IJ Baddeley, JA Watson, CA
GEODERMA 128:1-2 130-154
Global climate change and concerns about soil quality have led to a widespread interest in the opportunities that are available to sequester carbon in soils. To achieve a better understanding of the changes in C storage, we need to be able to accurately measure and model inputs and losses of C from soils. This in turn requires a thorough understanding of the biological processes involved and the way in which they are influenced by the soil’s physical and chemical environment. The amount of C present in a soil is determined by the difference between C addition and C loss. Because these fluxes are large relative to changes in C storage, net storage can be very difficult to measure, particularly in the short term. Carbon is added to soil from plant and animal materials deposited on the soil surface. It is known that approximately 50% of C assimilated by young plants can be transferred below ground; some is used for root construction and maintenance as well as root respiration; some organic C is lost to the soil through exudation and root turnover. A comparison of eight studies has shown that the input to the soil of root derived organic C during a growing season can range between 0.1 and 2.8 t C ha(-1). Quantifying inputs from different processes has proved difficult and the relative importance of exudation and root death under field conditions remains uncertain. The chemical composition of substrates released by exudation and root death is known to be very different. Exudates contain high concentrations of soluble organic substrates and as a consequence are highly labile, whereas additions of C from root death have structural organic substrates with lower potential decomposition rates. Losses of C from soil occur as a consequence of plant and microbial respiration. However, identifying the source of evolved CO2, whether it be from root or microbial respiration, is much more difficult. Some new methods using isotopic labelling and pool dilution have been developed to separate plant and microbial respiration, and despite difficulties, these promise to provide valuable information on the processes of C input and loss from soils.At a field scale measurements and models would suggest that soil and crop management can play a significant role in determining the extent of C sequestration by soils and the proportion of labile C present. A comparison of 11 field studies showed that soil respiration varies between 4 and 26 t C ha(-1) year(-1), with management such as tillage, drainage, grazing and manure application exerting a strong influence on the magnitude of fluxes. Net ecosystem exchange of C has been shown to be at least an order of magnitude lower than respiratory losses in comparable studies, but land management is important in determining the direction and magnitude of the C flux. Recent studies have suggested that although the overall quantity of C stored in European soils is increasing, this increase is confined largely to forested areas and that many cropped soils are losing soil organic matter. It is has been suggested that that the biological potential for C storage in European cropland lies between 9 and 120 Mt C year(-1). In order to take advantage of this potential and to develop management systems that promote C storage we need to achieve a better understanding of the processes of C input and loss, and develop improved models using pools that coincide with measurable soil C fractions. (c) 2004 Elsevier B.V. All rights reserved.
Transient future climate over the western United States using a regional climate model
Snyder, MA Sloan, LC
EARTH INTERACTIONS 9: -
Regional climate models (RCMs) have improved our understanding of the effects of global climate change on specific regions. The need for realistic forcing has led to the use of fully coupled global climate models (GCMs) to produce boundary conditions for RCMs. The advantages of using fully coupled GCM output is that the global-scale interactions of all components of the climate system ( ocean, sea ice, land surface, and atmosphere) are considered. This study uses an RCM, driven by a fully coupled GCM, to examine the climate of a region centered over California for the time periods 1980 - 99 and 2080 - 99. Statistically significant increases in mean monthly temperatures by up to 7 degrees C are found for the entire state. Large changes in precipitation occur in northern California in February ( increase of up to 4 mm day(-1) or 30%) and March ( decrease of up to 3 mm day(-1) or 25%). However, in most months, precipitation changes between the cases were not statistically significant. Statistically significant decreases in snow accumulation of over 100 mm (50%) occur in some months. Temperature increases lead to decreases in snow accumulation that impact the hydrologic budget by shifting spring and summer runoff into the winter months, reinforcing results of other studies that used different models and driving conditions.
Solanki, SK Krivova, NA Wenzler, T
INFLUENCE OF THE SUN’S RADIATION AND PARTICLES ON THE EARTH’S ATMOSPHERE AND CLIMATE 35:3 376-383
Measurements of solar irradiance have revealed variations at all the sampled time scales (ranging from minutes to the length of the solar cycle). One important task of models is to identify the causes of the observed (total and spectral) irradiance variations. Another major aim is to reconstruct irradiance over time scales longer than sampled by direct measurements in order to consider if and to what extent solar irradiance variations may be responsible for global climate change. Here, we describe recent efforts to model solar irradiance over the current and the previous two solar cycles. These irradiance models are remarkably successful in reproducing the observed total and spectral irradiance, although further improvements are still possible. (c) 2005 COSPAR. Published by Elsevier Ltd. All rights reserved.
Plant growth and water use efficiency of four Chinese conifer tree species under different air humidity
Zheng, Y Shimizu, H
PHYTON-ANNALES REI BOTANICAE 45:4 575-582
Air humidity is an important controlling factor for the establishment of tree seedlings. It is predicted that the annual amount of rainfall will decline in some parts of China due to the global climate change in the foreseeable future. There is limited information on the potential responses of this region’s forest to the global climate change. Our study investigated the responses of four major Chinese conifer tree species to air humidity variations. Seedlings of Pinus massoniana Lamb. var. massoniana, Pinus tabulaeformis Carr. var. tabulaeformis, Platycladus orientalis (Linn.) Franco cv. Sieboldii and Cunninghamia lanceolata (Lamb.) Hook were grown in controlled environment chambers under four different air humidity (RH: 40, 50, 60 and 70% or VPD: 2.4, 2.0, 1.6 and 1.2 kPa). Results showed that the growth of these four species responded to air humidity differently. P. massoniana was the most sensitive species, P. tabulaeformis and P. orientalis were less sensitive and C. lanceolata was the least sensitive species. However, the biomass increment (Delta biomass) and the relative growth rate (RGR) over the experimental period were higher under the RH 70% treatment than that under the 40% treatment for all the four species. Delta biomass and RGR were reduced by 54% and 47%, respectively, under the RH 40% treatment compared with those under the RH 70% treatment for P. massoniana, 24% and 12% for P. tabulaeformis, 22 % and 16 % for P. orientalis, 9% and 5% for C. lanceolata. The decreased growth under drier air conditions was partially due to the closure of leaf stomata and subsequently the depression of photosynthesis. Plants under higher humidity conditions had higher water use efficiency (WUE). There was a positive linear relationship between WUE and RH in all the four species. Our results may suggest that if air humidity becomes lower in some regions of China in the future, the area of distribution for the humidity sensitive species P. Massoniana may become smaller or this species may move to higher humidity region while the other three species will be less affected by this change.
The quantitative effects of population density and winter weather on the body condition of white-tailed deer (Odocoileus virginianus) in Nova Scotia, Canada
Garroway, CJ Broders, HG
CANADIAN JOURNAL OF ZOOLOGY-REVUE CANADIENNE DE ZOOLOGIE 83:9 1246-1256
Understanding the underlying mechanisms that cause variation in survival and the reproductive success of animals is essential for predicting variation in population parameters. To gain an understanding of the effects of density and winter weather severity on white-tailed deer, Odocoileus virginianus (Zimmermann, 1780), we examined the effects of current-year deer density and cumulative weekly average values for snow depth, rainfall, and the number of degrees below -15 degrees C until the time of death, as well as cumulative effects of density and snow depth over the previous one and two winters, on the body condition of adult females, adult males, and fawns. Model selection using Akaike’s Information Criterion and multi-model inference suggested that snow depth was the best predictor of body condition for all three age/sex groups. Winter rainfall was the next most influential predictor for adult females and adult males but was not important in determining fawn body condition. Temperature had the least influence on the body condition of all three age/sex groups. Deer density during the winter of death had minimal effects for all groups and we found no evidence that cumulative multiyear variables influenced body condition. We hypothesize that cohort variation may better explain previous findings showing effects of multiyear variables. A model for estimating the proportion of animals in poor body condition for each age/sex group is presented.
A hydrologic contribution to risk assessment for the Caspian Sea
Helms, M Evdakov, O Ihringer, E Nestmann, F
LIMNOLOGICA 35:3 114-122
The Caspian Sea (CS), the world’s largest inland sea, may also be considered as large-scale limnic system. Due to strong fluctuations of its water level during the 20th century and the flooding of vast areas in a highly vulnerable coastal zone, economic and environmental risk potentials have to be considered. Since the major water input into the CS is attributed to the Volga river, the understanding of its long-term flow process is necessary for an appropriate risk assessment for the CS and its coastal area. Therefore, a top-down approach based on statistical analyses of long-term Volga flow series is pursued. For the series of annual mean flow (MQ) of the Volga river basin during the 20th century, a complex oscillation pattern was identified. Analyses for multiple gauges in the Volga river basin and Eurasian reference basins revealed that this oscillation pattern resulted from the superposition of oscillations with periods of similar to 30 years (MQ) in the western part of the Volga river basin, and similar to 14 years (flow volume of snowmelt events) and similar to 20 years (flow volume of summer and autumn) in the eastern part of the Volga river basin (Kama river basin). Almost synchronous minima or maxima of these oscillations occurred just in the periods of substantial changes of the Caspian Sea level (CSL). It can thus be assumed that the described mechanism is fundamental for an understanding of the CSL development during the 20th century. Regarding the global climate change, it is still difficult to predict reliably the development of the CSL for the 21st century. Consequently, we suggest an ongoing, interdisciplinary research co-operation among climatology, hydrology, hydraulics, ecology and spatial data management. (c) 2005 Elsevier GmbH. All rights reserved.
Characterization of microsatellite loci in Schoenoplectus americanus (Cyperaceae)
Blum, MJ McLachlan, JS Saunders, CJ Herrick, JD
MOLECULAR ECOLOGY NOTES 5:3 661-663
Schoenoplectus americanus is a model organism for studying ecological and ecosystem responses of salt marsh plant communities to global climate change. Here we characterize 16 microsatellite loci in S. americanus to facilitate studies on the genetic basis of phenotypic responses to changing climate conditions such as elevated atmospheric carbon dioxide. Most loci also amplified in the morphologically similar sister species, Schoenoplectus pungens. Five loci exhibited species-specific alleles or distinct allelic size distributions that discriminate S. americanus from S. pungens.
Rates of soil creep, worldwide: weak climatic controls and potential feedback
Oehm, B Hallet, B
ZEITSCHRIFT FUR GEOMORPHOLOGIE 49:3 353-372
The rate of soil creep sets the tempo at which material is transferred from hill-slopes to fluvial systems over major portions of terrestrial landscapes. Hence, soil creep rates affect the rates of landscape evolution and delivery of terrigenous material to floodplains and eventually to the oceans. Herein, we compile data from all sources worldwide that arc readily available in the literature, and derive common, quantitative characteristics of soil creep from digitized soil displacement profiles that permit estimates of soil flux and comparison between diverse studies. We also search for systematic variations of creep rates with climate and explore potential feedbacks between creep rates and climate. Significant creep is found in a range of environments worldwide and is fueled by diverse physical and biological processes. The considerable inter-site variability overwhelms the dependence of creep rates on hillslope gradient and obscures, but does not conceal, the climate influence. We speculate that the general tendency for rapid creep to be associated with colder climates could exacerbate global climate change. A global rise in temperature, for example, could slow the sequestration of atmospheric CO2 as creep rates decrease by slowing two distinct pedogcnic processes: mineral weathering, which is sensitive function of processes that create and freshen mineral surfaces, and the subaerial delivery of organic carbon stored in soils to rivers and long-lived reservoirs.
Animal-borne sensors successfully capture the real-time thermal properties of ocean basins
McMahon, CR Autret, E Houghton, JDR Lovell, P Myers, AE Hays, GC
LIMNOLOGY AND OCEANOGRAPHY-METHODS 3: 392-398
Climate change is perhaps the most pressing and urgent environmental issue facing the world today. However our ability to predict and quantify the consequences of this change is severely limited by the paucity of in situ oceanographic measurements. Marine animals equipped with sophisticated oceanographic data loggers to study their behavior offer one solution to this problem because marine animals range widely across the world’s ocean basins and visit remote and often inaccessible locations. However, unlike the information being collected from conventional oceanographic sensing equipment, which has been validated, the data collected from instruments deployed on marine animals over long periods has not. This is the first long-term study to validate in situ oceanographic data collected by animal oceanographers. We compared the ocean temperatures collected by leatherback turtles (Dermochelys coriacea) in the Atlantic Ocean with the ARGO network of ocean floats and could find no systematic errors that could be ascribed to sensor instability. Animal-borne sensors allowed water temperature to be monitored across a range of depths, over entire ocean basins, and, importantly, over long periods and so will play a key role in assessing global climate change through improved monitoring of global temperatures. This finding is especially pertinent given recent international calls for the development and implementation of a comprehensive Earth observation system ( see http://iwgeo.ssc.nasa.gov/documents.asp?s=review) that includes the use of novel techniques for monitoring and understanding ocean and climate interactions to address strategic environmental and societal needs.
Prediction of expected global climate change by forecasting of galactic cosmic ray intensity time variation in near future based on solar magnetic field data
Belov, AV Dorman, LI Gushchina, RT Obridko, VN Shelting, BD Yanke, VG
INFLUENCE OF THE SUN’S RADIATION AND PARTICLES ON THE EARTH’S ATMOSPHERE AND CLIMATE 35:3 491-495
A method of prediction of expected part of global climate change caused by cosmic ray (CR) by forecasting of galactic cosmic ray intensity time variation in near future based on solar activity data prediction and determined parameters of convection-diffusion and drift mechanisms is presented. This gave possibility to make prediction of expected part of global climate change, caused by long-term cosmic ray intensity variation. In this paper, we use the model of cosmic ray modulation in the Heliosphere, which considers a relation between long-term cosmic ray variations with parameters of the solar magnetic field. The later now can be predicted with good accuracy. By using this prediction, the expected cosmic ray variations in the near Earth space also can be estimated with a good accuracy. It is shown that there are two possibilities: (1) to predict cosmic ray intensity for 1-6 months by using a delay of long-term cosmic ray variations relatively to effects of the solar activity and (2) to predict cosmic ray intensity for the next solar cycle. For the second case, the prediction of the global solar magnetic field characteristics is crucial. For both cases, reliable long-term cosmic ray and solar activity data as well as solar magnetic field are necessary. For solar magnetic field, we used results of two magnetographs (from Stanford and Kitt Peak Observatories). The obtained forecasting of long-term cosmic ray intensity variation we use for estimation of the part of global climate change caused by cosmic ray intensity changing (influenced on global cloudiness covering). (c) 2005 COSPAR. Published by Elsevier Ltd. All rights reserved.
Estimation of long-term cosmic ray intensity variation in near future and prediction of their contribution in expected global climate change
INFLUENCE OF THE SUN’S RADIATION AND PARTICLES ON THE EARTH’S ATMOSPHERE AND CLIMATE 35:3 496-503
On the basis of results obtained in our paper [Dorman, L.I. Long-term cosmic ray intensity variation and part of global climate change, controlled by solar activity through cosmic rays, Paper D2.1/C2.2/E3.1-0097-04. Adv. Space Res., 2004 (accepted)], we determine: the dimension of the Heliosphere (modulation region), radial diffusion coefficient and other parameters of convection-diffusion; drift mechanisms of long-term variations of cosmic ray (CR) dependence on particle energy; level of solar activity (SA); and generally, the solar magnetic field. We obtain this important information on the basis of CR and SA data in the past, taking into account the theory of convection-diffusion and global drift modulation of galactic CR in the Heliosphere. By using these results and other regularly published predictions of expected SA variation in the near future, as well as predictions of the next SA cycle, we may make predictions of long-term cosmic ray intensity variation expected in the near future (up to 10-12 years). In [Dorman, L.I. Long-term cosmic ray intensity variation and part of global climate change, controlled by solar activity through cosmic rays, Paper D2.1/C2.2/E3.1-0097-04. Adv. Space Res., 2004 (accepted)], properties of connections between long-term variation in CR intensity and some part of a global climate change were estimated, controlled by solar activity through CR. We show that in this way we may make predictions of some part of a global climate change expected in the near future (up to 10-12 years and maybe more, depending upon the period during which definite predictions of SA can be made), controlled by solar activity through CR. In this case, estimations of expected long-term changes in the planetary distribution of cutoff rigidities, which also influence CR intensity, as well as CR-influenced effects on global climate variation, become important. (c) 2005 COSPAR. Published by Elsevier Ltd. All rights reserved.
Model of the net primary productivity of terrestrial ecosystems in china and its response to climate change
Zheng, YR Xie, ZX Jiang, LH Chen, LJ Yu, YJ Zhou, GS Shimizu, H
PHYTON-ANNALES REI BOTANICAE 45:4 193-200
The present study proposed to distinguish agricultural vegetation from natural vegetation when modelling net primary productivity (NPP), and developed a NPP model specifically for agricultural vegetation in China. The new model and the ZHOU & ZHANG model 1996 were then used to simulate NPP for agricultural land and natural ecosystems in China, respectively. The results showed that the overall accuracy improved when simulating the present NPP. As a general trend, NPP declined from southeast to northwest, with the lowest NPP in the Xinjiang Autonomous region. Except in extremely and or extremely humid areas, agricultural NPP was usually lower than natural NPP, especially in northeastern China and the North China plain. The two models were also used to simulate NPP in China under three climatic change scenarios. The results demonstrated that if air temperature increased by 2 degrees C and rainfall decreased by 20 %, both low NPP and high NPP area would decrease, resulting in an increase of medium NPP area. The other two scenarios, characterized by a temperature increase of 2 degrees C, combined with precipitation increase of 20 % and with precipitation unchanged, showed a decrease in low NPP area and a increase in medium and high NPP area, however, the former resulted in a greater medium NPP increase. In conclusion, our approach supplied better predictions than those based on only a natural NPP model.
Sensitivity analysis of the tree distribution model PHENOFIT to climatic input characteristics: implications for climate impact assessment
Morin, X Chuine, I
GLOBAL CHANGE BIOLOGY 11:9 1493-1503
Species distributions are already affected by climate change. Forecasting their long-term evolution requires models with thoroughly assessed validation. Our aim here is to demonstrate that the sensitivity of such models to climate input characteristics may complicate their validation and introduce uncertainties in their predictions. In this study, we conducted a sensitivity analysis of a process-based tree distribution model PHENOFIT to climate input characteristics. This analysis was conducted for two North American trees which differ greatly in their distribution and eight different types of climate input for the historic period which differ in their spatial (local or gridded data) and temporal (daily vs. monthly) resolution as well as their type (locally recorded, extrapolated or simulated by General Circulation Models). We show that the climate data resolution (spatial and temporal) and their type, highly affect the model predictions. The sensitivity analysis also revealed, the importance, for global climate change impact assessment, of (i) the daily variability of temperatures in modeling the biological processes shaping species distribution, (ii) climate data at high latitudes and elevations and (iii) climate data with high spatial resolution.
On climate response to changes in the cosmic ray flux and radiative budget
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 110:A8 -
We examine the results linking cosmic ray flux ( CRF) variations to global climate change. We then proceed to study various periods over which there are estimates for the radiative forcing, temperature change and CRF variations relative to today. These include the Phanerozoic as a whole, the Cretaceous, the Eocene, the Last Glacial Maximum, the 20th century, as well as the 11- yr solar cycle. This enables us to place quantitative limits on climate sensitivity to both changes in the CRF, and the radiative budget, F, under equilibrium. Under the assumption that the CRF is indeed a climate driver, the sensitivity to variations in the globally averaged relative change in the tropospheric ionization I is consistently fitted with mu &3bond; ( dT(global)/ dI) approximate to 7.5 +/- 2 degrees K. Additionally, the sensitivity to radiative forcing changes is lambda &3bond; dT(global)/ dF = 0.35 +/- 0.09 degrees KW(-1)m(2), at the current temperature, while its temperature derivative is undetectable with (d lambda/ dT)(0) = - 0.01 +/- 0.04 m(2)W(-1). If the observed CRF/ climate link is ignored, the best sensitivity obtained is lambda = 0.54 +/- 0.12 degrees KW-1 m(2) and ( d lambda/ dT)(0) = - 0.02 +/- 0.05 m(2) W-1. Note that this analysis assumes that different climate conditions can be described with at most a linear function of T; however, the exact sensitivity probably depends on various additional factors. Moreover, l was mostly obtained through comparison of climate states notably different from each other, and thus only describes an average sensitivity. Subject to the above caveats and those described in the text, the CRF/ climate link therefore implies that the increased solar luminosity and reduced CRF over the previous century should have contributed a warming of 0.47 +/- 0.19 degrees K, while the rest should be mainly attributed to anthropogenic causes. Without any effect of cosmic rays, the increase in solar luminosity would correspond to an increased temperature of 0.16 +/- 0.04 degrees K.
Snow and glacier cover assessment in the high mountains of Sikkim Himalaya
HYDROLOGICAL PROCESSES 19:12 2375-2383
This study highlights the assessment of snow and glacier cover for possible inferences of global climate change impacts in high mountains like the Himalaya. The test catchment of the River Tista lies in the Sikkim state of the Indian Himalayan region, with steep mountains crossing nearly all ecozones, from subtropical to glacial. River flows are highly fluctuating, especially during the peak rainy season and snowmelt periods. Annual rainfall patterns are non-uniform and can cause large floods. Runoff and discharge downstream are highly dependent upon snow and glacier extent. The temporary storage of frozen water brings about a delay in seasonal runoff. Snow cover built up in the higher regions during the winter months melts in the spring-summer-autumn cycles and contributes to groundwater recharge. A spatial baseline inventory of snow cover/glacier, the permanent snowline and its short-term temporal changes in the remote high-mountain areas have been analysed using multidate Indian Remote Sensing Satellite data of 1992 to 1997. A geographic information system-based overlay has led to inferences on snow cover characteristics and the alignment, dimension, slope disposition, heights of the snout and associated features of each of the glaciers. Snow and glacier recession are to be monitored in future on a long-term basis to derive correlations with climate-change parameters. Copyright (c) 2005 John Wiley & Sons, Ltd.
The science, politics and economics of global climate change: Implications for the carbon sink projects
CURRENT SCIENCE 89:3 464-474
Drier summers cancel out the CO2 uptake enhancement induced by warmer springs
Angert, A Biraud, S Bonfils, C Henning, CC Buermann, W Pinzon, J Tucker, CJ Fung, I
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 102:31 10823-10827
An increase in photosynthetic activity of the northern hemisphere terrestrial vegetation, as derived from satellite observations, has been reported in previous studies. The amplitude of the seasonal cycle of the annually detrended atmospheric CO2 in the northern hemisphere (an indicator of biospheric activity) also increased during that period. We found, by analyzing the annually detrended CO2 record by season, that early summer (June) CO2 concentrations indeed decreased from 1985 to 1991, and they have continued to decrease from 1994 up to 2002. This decrease indicates accelerating springtime net CO2 uptake. However, the CO2 minimum concentration in late summer (an indicator of net growing-season uptake) showed no positive trend since 1994, indicating that lower net CO2 uptake during summer cancelled out the enhanced uptake during spring. Using a recent satellite normalized difference vegetation index data set and climate data, we show that this lower summer uptake is probably the result of hotter and drier summers in both mid and high latitudes, demonstrating that a warming climate does not necessarily lead to higher CO2 growing-season uptake, even in high-latitude ecosystems that are considered to be temperature limited.
Marmots on Great Basin mountaintops: Using genetics to test a biogeographic paradigm
Floyd, CH Van Vuren, DH May, B
ECOLOGY 86:8 2145-2153
Boreal mammals in the Great Basin have long been viewed as island-bound Pleistocene relicts because they occupy island-like patches of montane habitat separated by desert lowlands that presumably are impermeable to dispersal. Recent work, however, raised the possibility that dispersal among mountain ranges is an important process in the biogeography of boreal mammals in the Great Basin. We test this proposition using genetic variation in a representative species, the yellow-bellied marmot (Marinota flaviventris). A total of 332 marmots was sampled from 10 ranges and genotyped at six microsatellite loci. If the intervening desert lowlands are impermeable barriers to dispersal, then there should be no relationship between genetic distance and geographic distance among mountaintop populations, and genetic diversity should be diminished because gene flow would not be available to replace alleles lost over thousands of generations of isolation. Our results did not support these predictions. There was a strong correlation between genetic and geographic distance, demonstrating an isolation-by-distance pattern, and genetic diversity was high. Our results suggest that marmot populations in the Great Basin may be linked by dispersal, providing a mechanism to replenish genetic variation lost by drift. However, global climate change over the next several decades could make the desert lowlands more difficult to traverse, eventually transforming the boreal faunas of Great Basin mountaintops into the isolated relicts they were originally portrayed to be.
Are long-distance migrants constrained in their evolutionary response to environmental change? Causes of variation in the timing of autumn migration in a blackcap (S-atricapilla) and two garden warbler (Sylvia borin) populations
Pulido, F Widmer, M
BIRD HORMONES AND BIRD MIGRATIONS: ANALYZING HORMONES IN DROPPINGS AND EGG YOLKS AND ASSESSING ADAPTATIONS IN LONG-DISTANCE MIGRATION 1046: 228-241
Long-distance migratory birds often show little phenotypic variation in the timing of life-history events like breeding, molt, or migration. It has been hypothesized that this could result from low levels of heritable variation. If this were true, the adaptability of long-distance migratory birds would be limited, which would explain the vulnerability of this group of birds to environmental changes. The amount of phenotypic, environmental, and genetic variation in the onset of autumn migratory activity was assessed in two garden warbler (Sylvia borin) populations differing in breeding phenology and the length of the breeding season with the aim of investigating the effects of selection on the adaptability of long-distance migrants. High heritabilities and additive genetic variance components for the timing of autumn migration were found in both populations. Although genetic variation in the mountain population was lower than in the lowlands, this difference was not statistically significant. Moreover, no evidence was found for reduced levels of genetic variation in the garden warbler as compared to its sister species, the blackcap (S. atricapilla). Environmental variation, however, was markedly reduced in the garden warbler, suggesting that low levels of phenotypic variation typically found in long-distance migrants may be a consequence of environmental canalization of migratory traits. The buffering of environmental variation may be an adaptive response to strong stabilizing selection on the timing of migration. High environmental canalization of migration phenology in long-distance migrants could potentially explain low rates of immediate phenotypic change in response to environmental change.
Warming in Arctic intermediate and deep waters around Chukchi Plateau and its adjacent regions in 1999
Zhao, JP Gao, GP Jiao, YT
SCIENCE IN CHINA SERIES D-EARTH SCIENCES 48:8 1312-1320
Based on the data measured during Arctic scientific expedition of China in 1999, the characteristics of temperature and salinity distributions around the Chukchi Plateau and its adjacent regions have been studied. It was found that the intermediate water with temperature higher than 0.5 degrees C existed in all parts of a 640 km section with a maximum temperature of 0.85 degrees C indicating a strong signal of the warming in Arctic Intermediate Water in 1999. Two important phenomena are described in this paper. First, the temperature of warm water was horizontally nonuniform. In the area of Chukchi Plateau, the temperature was higher, the layer of warm water was thicker and the depth of the warm water core was shallower than those in the area of continental slope. The horizontal nonuniformity of the temperature distribution of warming water implies that the upward heat flux should also be nonuniform, thus exerting different effects on sea ice thickness, ice extent, and air-sea heat exchange. The mechanism to generate higher temperature in the plateau region was the bypassing of current around the plateau area caused by the special local topography, which restricted water exchange across the plateau and conserved heat in the water body. Second, the deep water down to 1400 m was also warming with a temperature increase of 0.2 degrees C. The warming in deep water reflects the occurrence of complicated heat redistribution processes in the intermediate water, which altered the thermal structure in the upper 1400 m. The warming data embody the obvious impact of global climate change on the Arctic Ocean and further studies are wanted.
Rates of erosion and topographic evolution of the Sierra Nevada, California, inferred from cosmogenic Al-26 and Be-10 concentrations
Stock, GM Anderson, RS Finkel, RC
EARTH SURFACE PROCESSES AND LANDFORMS 30:8 985-1006
Concentrations of cosmogenic Al-26 and Be-10 in cave sediments and bedrock surfaces, combined with studies of landscape morphology, elucidate the topographic history of the southern Sierra Nevada over the past 5 Ma. Caves dated by Al-26/Be-10 in buried sediments reveal that river incision rates were moderate to slow between c. 5 and 3 Ma (<= 0.07 mm a(-1)), accelerated between 3 and 1.5 Ma (c. 0.3 ram a(-1)), and then have subsequently become much slower (c. 0.02 mm a(-1)). Although the onset of accelerated incision coincides in time with both,postulated Pliocene tectonism and pronounced global climate change, we argue that it primarily represents the response to a discrete tectonic event between 3 and 5 Ma. Dated cave positions reveal that, prior to 3 Ma, river canyons displayed up to 1.6 km of local relief, suggesting that Pliocene rock uplift elevated pre-existing topography. Renewed incision beginning c. 3 Ma deepened canyons by up to 400 m, creating narrow inner gorges. Tributary streams exhibit strong convexities, indicating that the transient erosional response to Pliocene uplift has not yet propagated into upland surfaces. Concentrations of Al-26 and Be-10 in bare bedrock show that upland surfaces are eroding at slow rates of c. 0.01 mm a(-1). Over the past c. 3 Ma, upland surfaces eroded slowly while adjacent rivers incised rapidly, increasing local relief. Although relief production probably drove at least modest crestal uplift, considerable pre-Pliocene relief and low spatially averaged erosion rates suggest that climatically driven rock uplift is not sufficient to explain ail uplift implied by tilted markers at the western edge of the range. Despite the recent pulse of erosion, spatially averaged erosion rates are low, and have probably acted to preserve the broad topographic form of the Sierra Nevada throughout much of the late Cenozoic. Copyright (c) 2005 John Wiley & Sons, Ltd.
The case for carbon capture and storage
Stephens, JC Van der Zwaan, B
ISSUES IN SCIENCE AND TECHNOLOGY 22:1 68-76
Human activity releases approximately 25 billion tons of carbon dioxide into the atmosphere every year, building up the levels of greenhouse gases that are responsible for global climate change. The world’s forests store about 2 or 3 billion tons of that output annually, and the ocean absorbs 7 billion tons. Itis estimated that another 5 to 10 billion tons, as much as 40% of man-made carbon dioxide, could be removed from the atmosphere and safely stored away. Methods of storage are being researched, for example underground geological storage. Issues of safety and cost and feasibility need to be addressed before the government can push for carbon capture and storage.
Early tectonic uplift of the northern Tibetan Plateau
Dai, SA Fang, XM Song, CH Gao, JP Gao, DL Li, JJ
CHINESE SCIENCE BULLETIN 50:15 1642-1652
The Hexi Corridor is the northmost foreland basin of the Tibetan Plateau and its formation is controlled by the northern marginal fault of Tibet, Altyn Tagh Fault (ATF)-North Qilian Shan marginal Fault (NQF), and the southern Kuantan Shan-Longshou Shan Fault (KLF). So its study is important to understanding the mechanism of Tibet formation and its influence on global climate change. The oldest Cenozoic sediments in the Corridor is the Huoshaogou Formation which consists of terrigenous fine conglomerate, sandstone, sandy mudstone and mudstone, depositing in alluvial to lacustrine and fan delta sedimentary environments. Detailed paleomagnetic measurements of this sequence at Yumen clearly reveal eleven pairs of normal and reversed polarities. Fossil mammals found around the section support that most of the observed polarities can be well correlated with chrons between 13n and 18r of the standard geomagnetic polarity time scale, yielding ages of 40.2-33.35 Ma. The mean declinations of this sequence and its immediately above stratigraphy indicate an 18.3 degrees rapid clockwise rotation of the Hexi Corridor. Since this sequence has been strongly folded and is capped by an angular unconformity, we think that the presence of the thick alluvial fan conglomeration at the bottom of the foreland basin may indicate the initial deformation and uplift of the northern Qilian Shan. This process could occur at latest at 40.2 Ma, driven by the faults NQF and KLF that thrust onto the Hexi corridor respectively from its southern and northern margins. These faults are in an early response to the collision of India with Asia, while the unconformable termination and rotation of the Huoshaogou Formation at similar to 33.35 Ma indicate other early episode of rapid tectonic deformation and uplift of the northern Tibet.
Drought, tree rings, and reservoir design
JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION 41:4 949-958
Droughts constitute one of the most important factors affecting the design and operation of water resources infrastructure. Hydrologists ascertain their duration, severity, and pattern of recurrence from instrumental records of precipitation or streamflow. Under suitable conditions, and with proper analysis, tree rings obtained from long living, climate sensitive species of trees can extend instrumental records of streamflow and precipitation over periods spanning several centuries. Those tree-ring “reconstructions” provide a valuable insight about climate variability and drought occurrence in the Holocene, and yield long term hydrological data useful in the design of water infrastructure. This work presents a derivation of drought risk based on a renewal model of drought recurrence, a brief review of the basic theory of tree-ring reconstructions, and a stochastic model for optimizing the design of water supply reservoirs. Examples illustrate the methodology developed in this work and the supporting role that tree-ring reconstructed streamflow can play in characterizing hydrologic variability.
A 25 m.y. isotopic record of paleodiet and environmental change from fossil mammals and paleosols from the NE margin of the Tibetan Plateau
Wang, Y Deng, T
EARTH AND PLANETARY SCIENCE LETTERS 236:1-2 322-338
We use the carbon and oxygen isotopic compositions of fossil tooth enamel and paleosols to reconstruct the late Cenozoic history of vegetation and environmental change in the Linxia Basin at the northeastern margin of the Tibetan Plateau. The delta(13)C values of fossil enamel from a diverse group of herbivores and of paleosol carbonate and organic matter indicate that C4 grasses were either absent or insignificant in the Linxia Basin prior to similar to 2-3 Ma and only became a significant component of local ecosystems in the Quaternary. This is in striking contrast to what was observed in Pakistan, Nepal, Africa and the Americas where C4 plants expanded rapidly in the late Miocene as indicated by a positive delta(13)C shift in mammalian tooth enamel and paleosols. The delta(18)O results from the same herbivore species show several significant shifts in climate in the late Cenozoic. Most notably, a positive delta(18)O shift after similar to 7 Ma indicates a shift to warmer and/or drier conditions and is comparable in timing and direction to the delta(18)O shift observed in paleosol carbonates in Pakistan and Nepal. This late Miocene climate change observed in the Indian sub-continent and in the Linxia Basin, however, seems to be a regional manifestation of a global climate change. The lack of evidence for C4 plants in the Linxia Basin prior to similar to 2-3 Ma suggests that the East Asian summer monsoon, which brings precipitation into northern China during the summer and creates optimal conditions for the growth of C4 grasses, was probably not strong enough to affect this part of China throughout much of the Neogene. This implies that the Himalayan-Tibetan Plateau may not have reached the present-day elevation across its vast extent to support a strong East Asian monsoon system before similar to 2-3 Ma. Our data also suggest that regional climatic conditions played an important role in controlling the expansion of C4 plants. (c) 2005 Elsevier B.V. All rights reserved.
Arctic surface, cloud, and radiation properties based on the AVHRR Polar Pathfinder dataset. Part II: Recent trends
Wang, XJ Key, JR
JOURNAL OF CLIMATE 18:14 2575-2593
Over the past 20 yr, some Arctic surface and cloud properties have changed significantly. Results of an analysis of satellite data show that the Arctic has warmed and become cloudier in spring and summer but has cooled and become less cloudy in winter. The annual rate of surface temperature change is 0.057 degrees C for the Arctic region north of 60 degrees N. The surface broadband albedo has decreased significantly in autumn, especially over the Arctic Ocean, indicating a later freeze-up and snowfall. The surface albedo has decreased at an annual rate of -0.15% (absolute). Cloud fraction has decreased at an annual rate of -0.6% (absolute) in winter and increased at annual rates of 0.32% and 0.16% in spring and summer, respectively. On an annual time scale, there is no trend in cloud fraction. During spring and summer, changes in sea ice albedo that result from surface warming tend to modulate the radiative effect of increasing cloud cover. On an annual time scale, the all-wave cloud forcing at the surface has decreased at an annual rate of -0.335 W m(-2). indicating an increased cooling by clouds. There are large correlations between surface temperature anomalies and climate indices such as the Arctic Oscillation (AO) index for some areas, implying linkages between global climate change and Arctic climate change.
Does inland aquatic biodiversity have a future in Asian developing countries?
HYDROBIOLOGIA 542: 69-75
Inland aquatic ecosystems and their biodiversity in Asia represent a wide spectrum along a complex continuum of interacting ecological, economic, socio-cultural and political gradients all of which determine their present and future. Whereas the diversity of biophysical environments ensures a rich inland aquatic biodiversity, their present status has been greatly influenced by human societies that have depended on them for millennia. Besides high population densities and developmental pressures, socio-cultural factors, economic considerations and various policies concerning land and water resources are major factors responsible for the degradation of habitats and loss of biodiversity. The looming global climate change may only worsen the situation unless remedial measures are taken on a large scale and urgently. The future of aquatic biodiversity in Asian countries will depend upon a radical change in national policies on water, and upon research that can support the development of appropriate policies.
Species-energy relationship in the deep sea: a test using the Quaternary fossil record
Hunt, G Cronin, TM Roy, K
ECOLOGY LETTERS 8:7 739-747
Little is known about the processes regulating species richness in deep-sea communities. Here we take advantage of natural experiments involving climate change to test whether predictions of the species-energy hypothesis hold in the deep sea. In addition, we test for the relationship between temperature and species richness predicted by a recent model based on biochemical kinetics of metabolism. Using the deep-sea fossil record of benthic foraminifera and statistical meta-analyses of temperature-richness and productivity-richness relationships in 10 deep-sea cores, we show that temperature but not productivity is a significant predictor of species richness over the past c. 130 000 years. Our results not only show that the temperature-richness relationship in the deep-sea is remarkably similar to that found in terrestrial and shallow marine habitats, but also that species richness tracks temperature change over geological time, at least on scales of c. 100 000 years. Thus, predicting biotic response to global climate change in the deep sea would require better understanding of how temperature regulates the occurrences and geographical ranges of species.
What affects the magnitude of change in first arrival dates of migrant birds?
Tryjanowski, P Kuzniak, S Sparks, TH
JOURNAL OF ORNITHOLOGY 146:3 200-205
We analysed which among four factors (mean first arrival date, migration distance, changes in population size, detectability of species) influenced the magnitude of change (regression coefficient) in the first arrival dates of 30 migrant bird species in western Poland during 1983-2003. An examination suggested that several of these factors could be important: the regression coefficient was positively related to mean first arrival date (early species advancing their arrival date more) and negatively with change in population size (species in decline changing less). Moreover, significant differences in regression coefficient were detected between short and long distance migrants and between low detectable and highly detectable species. Undertaking a principal components analysis on the four factors produced an axis explaining 59% of the variance and whose positive values were associated with late arriving, long distance and low detectable species which were more likely to be in decline. However, the multi-collinearity of these factors is a problem that cannot be resolved here and we recommend that further work from different areas is needed to tease apart these effects.
Gradient analysis, the next generation: towards more plant-relevant explanatory variables
Lookingbill, TR Urban, DL
CANADIAN JOURNAL OF FOREST RESEARCH-REVUE CANADIENNE DE RECHERCHE FORESTIERE 35:7 1744-1753
The long history of gradient analysis is anchored in the observation that species turnover can be described along elevation gradients. This model is unsatisfying in that elevation is not directly relevant to plants and the ubiquitous “elevation gradient” is composed of multiple intertwined environmental factors. We offer an approach to landscape-scale vegetation analysis that disentangles the elevation gradient into its constituent parts through focused field sampling and statistical analysis. We illustrate the approach for an old-growth watershed in the Oregon Western Cascades. Our initial model of this system supports the common observation that forest community types are highly associated with specific elevation bands. By replacing elevation and other crude environmental proxy variables with estimates of more direct and resource gradients (radiation, temperature, and soil moisture), we create a vegetative model with stronger explanatory power than the proxy model in both cross-validation analysis and validation using an independent data set. The resulting model is also more biologically interpretable, which provides more meaningful insight into potential forest response to environmental change (e.g., global climate change scenarios). Acquiring a better mechanistic understanding of the relationship between plant communities and environmental predictor variables presents the next great challenge to community ecologists conducting gradient studies at landscape scales.
Elevation, substrate, and the potential for climate-induced tree migration in the White Mountains, New Hampshire, USA
Lee, TD Barrett, JP Hartman, B
FOREST ECOLOGY AND MANAGEMENT 212:1-3 75-91
We assessed the potential for climate-induced migration of tree species along elevation gradients in the White Mountains of New Hampshire. To do so, we determined the extent to which tree species abundances were associated with elevation, site, and substrate-related variables over a range of elevations (530-880 m) that included the transition from northern hardwoods to spruce-fir forest in the White Mountain National Forest (USA). One-hundred and ten, 400 m(2) plots were established along three elevational transects; transects were separated from each other by at least 9 km. In each plot, site and substrate characteristics were measured and all stems >= 2.5 cm dbh were tallied. Species importance values were calculated and those of the five most abundant tree species -balsam fir, red spruce, sugar maple, American beech, and yellow birch - were regressed on elevation and site-substrate characteristics. Plots were ordinated using detrended correspondence analysis and their first and second axis scores were regressed on elevation and site-substrate characteristics. Both elevation and site-substrate characteristics - parent material type in particular - were important predictors of importance value. Balsam fir and red spruce abundance increased with elevation and, at all elevations, reached greatest abundance on shallow-to-rock parent materials. Fir showed greater abundance on north-facing than on south-facing slopes. Sugar maple and American beech declined with elevation and both, but especially sugar maple, were associated with fine and compact tills. Yellow birch, which did not show any association with substrate characteristics, increased to about 770 m, then declined. The frequency of different parent material types changed with elevation, with deep, fine and compact tills becoming less frequent - and shallow soils (rock within 50 cm of soil surface) becoming more frequent - with elevation. If the tree species-substrate associations described here are causal, then the elevational patterns of species abundance observed today are a consequence of both edaphic and climatic factors. As a consequence, vegetation response to climatic warming may be complex. While warming may result in upward migration of yellow birch and American beech, sugar maple, confronted with reduced availability of suitable substrate at high elevations, will likely show little upward response. Red spruce and balsam fir may persist on thin soils at lower elevations unless displaced by eastern hemlock. Thus, climatic warming will likely alter traditionally recognized tree assemblages in this region. (c) 2005 Elsevier B.V. All rights reserved.
Genetic diversity and regional identity in the Australian remnant Nothofagus moorei
Taylor, KJ Lowe, AJ Hunter, RJ Ridgway, T Gresshoff, PM Rossetto, M
AUSTRALIAN JOURNAL OF BOTANY 53:5 437-444
Nothofagus moorei (F. Muell.) Krasser has a disjunct and narrow distribution in south-eastern Australian cool temperate rainforest. To assess the conservation-genetic priorities for this species, the genetic diversity of 20 populations sampled from the largest remnant patches at northern and southern distributional extremes, the McPherson and Barrington ranges (a total of 146 individuals), was investigated by using inter simple sequence repeats (ISSR). Regeneration in northern regions of N. moorei has been documented to be predominantly by vegetative means, but our results indicate little evidence of clonality outside the multi-stemmed rings of trees. In addition, genetic diversity was considerably higher in the northern (McPherson, h = 0.1613) than in the southern range (Barrington, h = 0.1159), and genetic differentiation was significantly positively correlated with geographic distance in the former region, but not the latter. Total intraspecific variation was moderate, as measured by Shannon’s diversity index, I = 0.2719, and Nei’s gene diversity, h = 0.1672, and is considered at the high end of spectrum for estimates of narrow endemic species. An analysis of molecular variation indicated that the majority of genetic variation is partitioned among individuals within population (60%; P < 0.001), rather than among populations within regions (10%; P < 0.001). However, a large and significant component of the measured diversity was partitioned between northern and southern regions (29%; P < 0.001). Several hypotheses are outlined to explain these differences and management implications are discussed. However, given the narrow range, poor dispersal mechanism and restriction to cool temperate rainforest, the continued existence of N. moorei is most threatened by environmental instability and habitat loss resulting from global climate change. In this context the northern regions of the species are most at risk and extinction of such populations would lead to a significant loss of genetic variation for the species as a whole.
Alluvial stratigraphic evidence for channel incision during the Mediaeval Warm Period on the central Great Plains, USA
Daniels, JM Knox, JC
HOLOCENE 15:5 736-747
Alluvial valley fills from tributaries to the upper Republican River, southwest Nebraska, USA, provide soil- and morpho-stratigraphic evidence for an episode of channel incision that occurred between c. I 100 and 800 C-14 yr BP, based on 11 new radiocarbon ages. This local episode of channel incision correlates with other alluvial stratigraphic studies from the central Great Plains and demonstrates regionally synchronous fluvial behaviour. Proxy records of palaeohydrologic conditions in and around the Great Plains (including lacustrine, aeolian and geomorphological sources) indicate that channel incision correlates with a multicentennial episode of common, widespread drought. Temporally, this drought episode corresponds to the period recognized in many regions as the Mediaeval Warm Period (MWP). Therefore, this research demonstrates: (1) a relationship in the semi-arid central Great Plains between drought and increased fluvial incision; and (2) a local/regional geomorphic response to a particular episode of global climate change.
A multigenerational game model to analyze sustainable development
ANNALS OF OPERATIONS RESEARCH 137:1-4 369-386
This paper deals with a multigeneration game that provides a new rationale for representing time preference in very long term cost benefit analysis, as it happens typically in the economics of global climate change. One defines an intergenerational game where each generation has a random life duration and transfers the control of the economic system to the next generation at the end of its life. The payoff to a generation is a discounted sum of the expected consumption by the whole infinite sequence of generations, starting with the current one. The equilibrium is characterized by a dynamic programming equation; a unique solution is proved to exist; a numerical technique is proposed and implemented on a continuous time simplified version of the model DICE94. The results show the influence of this form of altruism on the asymptotic steady states of the economy subject to a global climate change effect.
Equity and justice in climate change adaptation amongst natural-resource-dependent societies
Thomas, DSG Twyman, C
GLOBAL ENVIRONMENTAL CHANGE-HUMAN AND POLICY DIMENSIONS 15:2 115-124
Issues of equity and justice are high on international agendas dealing with the impacts of global climate change. But what are the implications of climate change for equity and justice amongst vulnerable groups at local and sub-national levels? We ask this question for three reasons: (a) there is a considerable literature suggesting that the poorest and most vulnerable groups will disproportionately experience the negative effects of 21st century climate change; (b) such changes are likely to impact significantly on developing world countries, where natural-resource dependency is high; and (c) international conventions increasingly recognise the need to centrally engage resource stakeholders in agendas in order to achieve their desired aims, as part of more holistic approaches to sustainable development. These issues however have implications for distributive and procedural justice, particularly when considered within the efforts of the UNFCCC. The issues are examined through an evaluation of key criteria relating to climate change scenarios and vulnerability in the developing world, and second through two southern African case studies that explore the ways in which livelihoods are differentially impacted by (i) inequitable natural-resource use policies, (ii) community-based natural-resource management programmes. Finally, we consider the placement of climate change amongst the package of factors affecting equity in natural-resource use, and whether this placement creates a case for considering climate change as ‘special’ amongst livelihood disturbing factors in the developing world. (C) 2004 Elsevier Ltd. All rights reserved.
Impacts of climate and land-cover changes in arid lands of Central Asia
Lioubimtseva, E Cole, R Adams, JM Kapustin, G
JOURNAL OF ARID ENVIRONMENTS 62:2 285-308
Despite the growing understanding of the global climate change, great uncertainties exist in the prediction of responses of and regions to global and regional, natural and human-induced climate change. Meteorological data series show a steady increase of annual and winter temperatures in Central Asia since the beginning of the 20th century that might have a strong potential impact on the region’s natural ecosystems, agricultural crops, and human health. Analyses of the NOAA AVHRR temporal series since the 1980s showed a decrease in aridity from 1991-2000 compared to 1982-1990. While most climate models agree that the temperature in and Central Asia will increase by 1-2 degrees C by 2030-2050, precipitation projections vary from one model to another and projected changes in the aridity index for different model runs show no consistent trend for this region. Local and regional human impacts in and zones can significantly modify surface albedo, as well as water exchange and nutrient cycles that could have impacts on the climatic system both at the regional and global scales. (c) 2005 Elsevier Ltd. All rights reserved.
A regional, multi-sectoral and integrated assessment of the impacts of climate and socio-economic change in the UK
Holman, IP Rounsevell, MDA Shackley, S Harrison, PA Nicholls, RJ Berry, PM Audsley, E
CLIMATIC CHANGE 71:1-2 9-41
Policy makers and stakeholders are increasingly demanding impact assessments which produce policy-relevant guidance on the local impacts of global climate change. The ‘Regional Climate Change Impact and Response Studies in East Anglia and North West England’ (RegIS) study developed a methodology for stakeholder-led, regional climate change impact assessment that explicitly evaluated local and regional (sub-national) scale impacts and adaptation options, and cross-sectoral interactions between four major sectors driving landscape change (agriculture, biodiversity, coasts and floodplains and water resources). The ‘Drivers-Pressure-State-Impact-Response’ (DPSIR) approach provided a structure for linking the modelling and scenario techniques. A 5 x 5 km grid was chosen for numerical modelling input (climate and socio-economic scenarios) and output, as a compromise between the climate scenario resolution (10 x 10 km) and the detailed spatial resolution output desired by stakeholders. Fundamental methodological issues have been raised by RegIS which reflect the difficulty of multi-sectoral modelling studies at local scales. In particular, the role of scenarios, error propagation in linked models, model validity, transparency and transportability as well as the use of integrated assessment to evaluate adaptation options to climate change are examined. Integrated assessments will provide new insights which will compliment those derived by more detailed sectoral assessments.
The mystery of masting in trees
Koenig, WD Knops, JMH
AMERICAN SCIENTIST 93:4 340-347
This article describes the ecological and economic consequences of masting anddiscusses what causes seed production to vary so widely. A review of the latest research into proposed mechanisms that govern the synchronous production ofseed across geographic areas, and on the uncertain effects of global climate change on ecosystems in which masting plays a crucial role, is presented.
Variations in tropical convection as an amplifier of global climate change at the millennial scale
Ivanochko, TS Ganeshram, RS Brummer, GJA Ganssen, G Jung, SJA Moreton, SG Kroon, D
EARTH AND PLANETARY SCIENCE LETTERS 235:1-2 302-314
The global expression of millennial-scale climatic change during the glacial period and the persistence of this signal in Holocene records point to atmospheric teleconnections as the mechanism propagating rapid climate variations. We suggest rearrangements in the tropical convection system globally affected the concentration and location of atmospheric water vapour and modulated terrestrial and marine emissions of CH4 and N2O, providing a tropical mechanism of amplifying and perpetuating millennial-scale climate changes. A multi-proxy reconstruction reflecting various aspects of the intensity of the Arabian Sea Summer Monsoon shows strong millennial-scale variability over the past 90 kyr in which low intensity is associated with a southern shift of the Intertropical Convergence Zone (ITCZ) and an eastward shift in the equatorial convergence zone. The monsoon reconstruction, which is based on new data from a Somali margin sediment core, is supported by previously reported tropical paleoclimatic records and suggests that global scale millennial climatic variability is in part driven by modulations in the tropical hydrological cycle and tropical emissions of the greenhouse gases CH4 and N2O. (c) 2005 Elsevier B.V. All rights reserved.
North Atlantic weather oscillation and human infectious diseases in the Czech Republic, 1951-2003
EUROPEAN JOURNAL OF EPIDEMIOLOGY 20:3 263-270
Longitudinal correlation between the North Atlantic Oscillation large-scale weather system (NAO) and the annual incidence rate of 14 viral, bacterial and protozoan national notifiable human diseases in the Czech Republic was examined. In simple correlation, cases of salmonellosis, erysipelas, infectious mononucleosis and toxoplasmosis were positively correlated with the winter NAO index, while hepatitis A and shigellosis were negatively correlated, and the other diseases tested (rubella, mumps, chickenpox., tick-borne encephalitis, Lyme borreliosis, leptospirosis, tularemia and scarlet fever) were uncorrelated with NAO. However, 8 of the 14 diseases also revealed a significant time trend, either increasing (infectious mononucleosis, salmonellosis, erysipelas, toxoplasmosis) or decreasing (hepatitis A, scarlet fever, leptospirosis, shigellosis) during the period. When the effect of NAO on incidence of the diseases was then controlled for calendar year using partial correlation analysis and detrended regression, only toxoplasmosis and infectious mononucleosis were found significantly positively correlated with the NAO when the index was lagged 1 or 2 years, and leptospirosis was correlated negatively with a lag of 2 years. Large-scale weather changes as described by NAO therefore do not seem to be a crucial factor in the fluctuation of annual incidence rate of the majority of tested infectious diseases in the Czech Republic, while other factors, especially social and public health circumstances, are obviously more important.
Responses of deciduous forest trees to severe drought in Central Europe
Leuzinger, S Zotz, G Asshoff, R Korner, C
TREE PHYSIOLOGY 25:6 641-650
In 2003, Central Europe experienced the warmest summer on record combined with unusually low precipitation. We studied plant water relations and phenology in a 100-year-old mixed deciduous forest on a slope (no ground water table) near Basel using the Swiss Canopy Crane (SCC). The drought lasted from early June to mid September. We studied five deciduous tree species; half of the individuals were exposed to elevated CO2 concentration ([CO2]) (530 ppm) using a free-air, atmospheric CO2-enrichment system. In late July, after the first eight weeks of drought, mean predawn leaf water potential about 30 m above ground was -0.9 MPa across all trees, dropping to a mean of -1.5 MPa in mid-August when the top 1 m of the soil profile had no plant accessible moisture. Mean stomatal conductance and rates of maximum net photosynthesis decreased considerably in mid-August across all species. However, daily peak values of sap flow remained surprisingly constant over the whole period in Quercus petraea (Matt.) Liebl., and decreased to only about half of the early summer maxima in Fagus sylvatica L. and Carpinus betulus L. (stomatal down-regulation of flux). Although we detected no differences in most parameters between CO2-treated and control trees, predawn leaf water potential tended to be less negative in trees exposed to elevated [CO2]. Leaf longevity was greater in 2003 compared with the previous years, but the seasonal increase in stem basal area reached only about 75% of that in previous years. Our data suggest that the investigated tree species, particularly Q. petraea, did not experience severe water stress. However, an increased frequency of such exceptionally dry summers may have a more serious impact than a single event and would give Q. petraea a competitive advantage in the long run.
Effects of shore height, wave exposure and geographical distance on thermal niche width of intertidal fauna
Davenport, J Davenport, JL
MARINE ECOLOGY-PROGRESS SERIES 292: 41-50
Environmental temperature is a controlling factor in ecology and is influenced by global climate change. Upper/lower thermal limits for 10 species of. sessile/sedentary invertebrates were established on a single rocky shore. Two species with different reproductive strategies (Littorina littorea, Nucella lapillus) from 3 Scottish and 3 Irish shores were investigated to test effects of small scale (< 10 km) or larger scale (ca. 500 km) distances, and shore height on upper lethal temperature. At 3 sheltered and 3 exposed shores in Ireland, thermal responses of N. lapillus from the middle of their vertical distribution were compared. Amongst the 10 species from a single shore, thermal niche width rose asymptotically with maximum height of distribution on the shore and maximum emersion time. Median upper lethal temperature and median lower lethal temperature were closely correlated. For 8 species on the middle and upper shore, there were significant linear relationships between shore height and the variables upper lethal temperature, lower lethal temperature and thermal niche width. L. littorea upper lethal temperature was found not to vary with shore height, varied little over small geographical distances, but was significantly higher in Ireland than in Scotland. N, lapillus upper lethal temperature was higher in animals collected from the upper limit of distribution on the shore than in dogwhelks from the lower limit of distribution, was higher in animals taken from sheltered shores than from exposed shores and showed significant local differences. Upper lethal temperature was higher in Scottish than Irish dogwhelks.
Uncertainty assessment of spatial patterns of soil organic carbon density using sequential indicator simulation, a case study of Hebei province, China
Zhao, YC Shi, XZ Yu, DS Wang, HJ Sun, WX
CHEMOSPHERE 59:11 1527-1535
The spatial patterns of soil organic carbon (SOC) are closely related to the global climate change. In quantifying the spatial patterns of SOC density, the concept of uncertainty of the SOC density values at unsampled locations is particularly important because such uncertainty can be propagated into the subsequent global climate change modelling and has fundamental impacts on the ultimate results of the model. A total of 361 SOC density data of topsoil (0-20 cm) in Hebei province and sequential indicator simulation (SIS) were applied to perform a conditional stochastic simulation in this study to quantitatively assess the uncertainty of mapping SOC density. The results showed that a great variation exists in the SOC density data. The conditional variance of 500 realizations generated by SIS was larger in mountainous areas of the study area where the SOC density fluctuated the most, and the uncertainty was smaller on the plain area where SOC density was consistently small. Realizations generated by SIS can represent the possible spatial patterns of SOC density without smoothing effect. A set of realizations can be used to explore all possible spatial patterns of SOC density and provide a visual and quantitative measure of the spatial uncertainty of mapping SOC density. With a given threshold of SOC density, SIS can quantitatively assess both local uncertainty and spatial uncertainty of SOC density that is greater the threshold. (c) 2005 Elsevier Ltd. All rights reserved.
Detriments to post-bleaching recovery of corals
McClanahan, TR Maina, J Starger, CJ Herron-Perez, P Dusek, E
CORAL REEFS 24:2 230-246
Predicting the response of coral reefs to large-scale mortality induced by climate change will depend greatly on the factors that influence recovery after bleaching events. We experimentally transplanted hard corals from a shallow reef with highly variable seawater temperature ( 23 - 36 degrees C) to three unfished marine parks and three. shed reefs with variable coral predator abundance and benthic cover. The transplanted corals were fragmented colonies collected from a reef that was relatively undisturbed by the 1997 - 1998 warm-water temperature anomaly, one of the most extreme thermal events of the past century, and it was assumed that they would represent corals likely to succeed in the future temperature environment. We examined the effects of four taxa, two fragment sizes, an acclimation period, benthic cover components, predators and tourists on the survival of the coral fragments. We found the lowest survival of transplants occurred in the unfished marine parks and this could be attributed to predation and not tourist damage. The density of small coral recruits approximately 6 months after the spawning season was generally moderate ( similar to 40 - 60/m(2)), and not different on fished and unfished reefs. Coral recovery between 1998 and 2002 was variable ( 0 - 25%), low ( mean of 6.5%), and not different between fished and unfished reefs. There was high variability in coral mortality among the three unfished areas despite low variation in estimates of predator biomass, with the highest predation occurring in the Malindi MNP, a site with high coralline algal cover. Stepwise multiple regression analysis with 14 variables of coral predators and substratum showed that coralline algae was positively, and turf algae negatively associated with mortality of the transplants, with all other variables being statistically insignificant. This suggests that alternate food resources and predator choices are more important than predator biomass in determining coral survival. Nonetheless, large predatory fish in areas dominated by coralline algae may considerably retard recovery of eurythermal corals. This will not necessarily retard total hard coral recovery, as other more predator-tolerant taxa can recover. Based on the results, global climate change will not necessarily favor eurythermal over stenothermal coral taxa in remote or unfished reefs, where predation is a major cause of coral mortality.
Fire in African savanna: Testing the impact of incomplete combustion on pyrogenic emissions estimates
Smith, AMS Wooster, MJ Drake, NA Dipotso, FM Perry, GLW
ECOLOGICAL APPLICATIONS 15:3 1074-1082
African savannah fires are key sources of trace gases and aerosols, yet their true magnitude remains relatively poorly constrained. Here we present a detailed investigation of the amount of unburned material remaining in the ash produced by such fires, and examine whether this quantity needs to be considered when calculating atmospheric emissions. Emissions estimates for individual fires are usually based upon a calculation of the amount of fuel biomass combusted, usually estimated via a “simple subtraction” of the pre- and post-fire fuel loads. However, certain studies have concluded that this approach leads to gross overestimation of emissions, by perhaps 100%, due to the fact that a proportion of unburned fuel normally remains in the “charred” ash and that the simple subtraction method fails to take this fully into account. Whilst this latter point is true, we show that the mathematical relationship used previously to calculate the implications of this for emissions calculation is flawed. We demonstrate a new first-principles derivation of the quantity of mass combusted, taking into account any fuel remaining in the ash via measurement of ash mass loss on ignition (LOI). Using data from dry-season experimental fires in Botswana, we compared estimates of biomass combusted calculated via our LOI-based method to those obtained via the simple subtraction approach. We found a mean difference of < 10%, far less than the factor of 2 difference obtained when using the previous erroneous formula. Similar results are obtained for carbon and nitrogen emissions, and the findings are further supported by reassessment of previous data from early-to-mid-dry season savanna fires in Tanzania. These results indicate that the simple subtraction method overestimates emissions by far less than previously suggested, and that the method is likely to provide sufficient accuracy in most situations where emissions calculations are required. For fires where very substantial amounts of unburned material are expected to remain within the ash, and where an LOI-based approach to emissions calculation may therefore be particularly warranted, it is important that the correct formula derived herein is used, since errors inherent in the previous formula increase with increasing ash LOI.
Forecasting climate change effects on salamander distribution in the highlands of central Mexico
Parra-Olea, G Martinez-Meyer, E de Leon, GFP
BIOTROPICA 37:2 202-208
A generalized decline of amphibian populations is occurring worldwide. The causes for such a decline are not completely understood; however, climate change has been identified as a possible cause for amphibian extinction, among others. Ecological niche modeling has proven to be a useful tool to predict potential distribution of species in the context of climatic changes. In this paper, we used the Genetic Algorithm for Rule-set Prediction (GARP) to model the potential distributions of two species of plethodontid salamanders: Pseudoeurycea cephalica and P leprosa. We projected their potential distributions under climatic scenarios expected in 50 yr based on a conservative scenario of global climate change and assuming a moderate dispersal ability for both species. Our analyses suggest that climate change effects may pose an additional long-term risk to both species of plethodontid salamanders, with a more dramatic scenario in the case of P leprosa. By the year 2050, this species may lose almost 75 percent of its distributional area, and this projection is even worse when deforestation (in the way it is occurring at present) is considered within the predicted model. Our results concur with those obtained for species with limited dispersal capability because they do not track changing climates, but rather face a loss of distributional area. The survival of these species is not secure, even though their potential distributional area falls within a considerable number of natural protected areas.
Interdisciplinary oceanographic observations: the wave of the future
Dickey, TD Bidigare, RR
SCIENTIA MARINA 69: Suppl. 1 23-42
Oceanographic measurements, though difficult and expensive, are essential for effective study, stewardship, preservation, and management of our oceanic and atmospheric systems. Ocean sciences have been driven by technologies enabling new observations, discoveries, and modelling of diverse interdisciplinary phenomena. Despite rapid advances in ocean sampling capabilities, the numbers of disciplinary variables that are necessary to solve oceanographic problems are large and increasing. In addition, the time and space scales of key processes span over ten orders of magnitude; presently, there remain major spectral gaps in our sampling. Thus, undersampling presents the main limitation to our understanding of global climate change; variability in fish biomass and regime shifts; and episodic and extreme events. Fortunately, recent advances in ocean platforms and in situ autonomous sampling systems and satellite sensors are enabling unprecedented rates of data acquisition as well as the expansion of temporal and spatial coverage. Consequently, improved sampling strategies will lead to a reduction in ocean forecasting error for predictions of a multitude of atmospheric and oceanic processes. Nonetheless, major challenges remain to massively increase the variety and quantity of ocean measurements and to effectively coordinate, synthesize, and distribute oceanographic data sets. In particular, numbers of measurements are limited by the costs of instruments and their deployment as well as data processing and production of useful data products and visualizations. Looking forward, many novel and innovative technologies involving computing, nanotechnology, robotics, information and telemetry technologies, space sciences, and molecular biology are being developed at a fast pace for numerous applications (Kaku, 1997; Kurzweil, 1999). It is anticipated that several of these can and will be transitioned to the ocean sciences and will prove to be extremely beneficial for oceanographers in the next few decades. Already, autonomous, ‘robotic’ in situ sampling, high spectral resolution optical and chemical instrumentation, multi-frequency acoustics, and biomolecular techniques are being utilized by a limited number of oceanographers. Also, increased temporal and spatial sampling capabilities for expanding numbers of interdisciplinary variables are being accelerated thanks to both new technologies and utilization of data assimilation models coupled with autonomous sampling platforms. Data networks coupled with internet connectivity are rapidly increasing access to and utilization of data sets. In this essay, we review recent technological progress for solving some key oceanographic problems and highlight some of the foreseeable challenges and opportunities of ocean science technologies and their applications.
Risk in irrigation water supply and the effects on food production
JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION 41:3 679-692
This paper examines irrigation water supply deficit and associated risk indicators due to random climate events and potential effects on irrigated food production during the period 1996 to 2025 for seven river basins in the USA, China, and India. An integrated water and food model with global scope is applied for the analysis. The global climate regime during 1961 to 1990 is used to generate 30 climatic scenarios for the time period 1996 to 2025, and these scenarios are applied to the model in order to characterize the randomness of precipitation, runoff, and evapotranspiration, which affects both irrigation water supply and demand. The risk with random climate events is represented by reliability, variability, and vulnerability from different perspectives. Regarding irrigation water supply, Colorado will bear an increasingly unstable situation although the average water supply relative to the demand will maintain at a relatively high level; selected basins in China and India indicate that significantly lower levels of reliability and more deleterious affects from drought can be expected, but under a less variable condition due to assumed water storage increase. From 1996 to 2025, the effects of water deficits on irrigated food production are characterized with a nonlinear phenomenon and food production loss will be more sensitive to irrigation water supply deficit in the future. Future work following this paper needs to consider the impact of global climate change and the water quality of the irrigation return flow and result verification by local studies.
Water-saving approaches for improving wheat production
Deng, XP Shan, L Inanaga, S Inoue, M
JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 85:8 1379-1388
The greatest fear of global climate change is drought. World-wide, 61% of countries receive rainfall of less than 500 mm annually; domestication of wheat first occurred in such a semiarid region of southwestern Asia, and it seems that wheat foods originally came from dryland gardens. Wheat plants respond to drought through morphological, physiological and metabolic modifications in all plant parts. At the cellular level, plant responses to water deficit may result from cell damage, whereas other responses may correspond to adaptive processes. Although a large number of drought-induced genes have been identified in a wide range of wheat varieties, a molecular basis for wheat plant tolerance to water stress remains far from being completely understood. The rapid translocation of abscissic acid (ABA) in shoots via xylem flux, and the increase of ABA concentration in wheat plant parts cot-relate with the major physiological changes that occur during plant response to drought. It is widely accepted that ABA mediates general adaptive responses to drought. For a relatively determinate target stress environment, and with stable genotype x environment interaction, the probability for achieving progress is high. This approach will be possible only after we learn more about the physiology and genetics of wheat plant responses to water stress and their interactions. The difficulties encountered by molecular biologists in attempting to improve crop drought tolerance are due to our ignorance in agronomy and crop physiology and not to lack of knowledge or technical expertise in molecular biology. (c) 2005 Society of Chemical Industry.
Ecosystem and paleohydrological response to Quaternary climate change in the Bonneville Basin, Utah
Balch, DP Cohen, AS Schnurrenberger, DW Haskell, BJ Garces, BLV Beck, JW Cheng, H Edwards, RL
PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY 221:1-2 99-122
We report the results of a detailed paleoecological study of the Bonneville basin covering the last similar to 280,000 yr. Our study used fossil ostracodes and a sedimentological record obtained from the August 2000 GLAD800 drilling operation at Great Salt Lake. We analyzed 125 samples, taken at similar to 1 in intervals from Site 4 (GSL00-4), for ostracodes and other paleoecologic and sedimentologic indicators of environmental change. Multivariate analyses applied to the ostracode data and qualitative analyses of fossil and sedimentological data indicate an alternation between three major environments at the core site over the cored interval: (1) shallow saline or hypersaline lakes; (2) salt or freshwater marshes;, and (3) occasional deep freshwater lakes. These environmental changes are consistent with shoreline studies of regional lake level fluctuations, but provide considerable new detail on both the timing and environmental conditions associated with the various lake phases. Our age model (using C-14, U- series, tephra and biostratigraphic chronologies) allowed us to associate the core’s record of regional paleohydrology with the marine oxygen isotope stages of global climate change. The core contains continuous records for the last four glacial/interglacial sequences. Salt/freshwater marshes were common during the interglacials and deep freshwater conditions correspond with maximum global ice volume in OIS 2, and before a maximum in global ice during OIS 6. Immediately following deep lake phases, crashes in lake level from rapid desiccation resulted in the deposition of thick evaporite units. Our study suggests that the climate of the Great Salt Lake catchment appears to have been drier during OIS 6 than during OIS 2. We compare our record of environmental change during OIS 6 glaciation with other records from the western United States and find that the overall pattern of climate was similar throughout the West, but differences in the timing of climate change (i.e. when a region became drier or moister) are common. (c) 2005 Elsevier B.V. All rights reserved.
Dynamic changes of anti-oxidative enzymes of 10 wheat genotypes at soil water deficits
Shao, HB Liang, ZS Shao, MA Sun, Q
COLLOIDS AND SURFACES B-BIOINTERFACES 42:3-4 187-195
Drought is a world-spread problem seriously influencing crop production and quality, the loss of which is the total for other natural disasters, with increasing global climate change making the situation more serious. Wheat is the staple food for more than 35% of world population, so wheat anti-drought physiology study is of importance to wheat production and biological breeding for the sake of coping with abiotic and biotic conditions. Much research is involved in this hot topic, but the pace of progress is not so large because of drought resistance being a multiple-gene-control quantitative character and wheat genome being larger (16,000 Mb). On the other hand, stress adaptive mechanisms are quite different, with stress degree, different growth and developmental stages, time course, materials and experimental plots, thus increasing the complexity of the issue in question. Additionally, a little study is related to the whole life circle of wheat, which cannot provide a comprehensive understanding of its anti-drought machinery. We selected 10 kinds of wheat genotypes as materials, which have potential to be applied in practice, and measured change of relative physiological indices through wheat whole growing developmental circle (i.e. seedling, tillage and maturing). Here, we reported the dynamic anti-oxidative results of whole stage (i.e. seedling, tillage and maturing) in terms of activities of POD, SOD, CAT of 10 wheat genotypes as follows: (1) 10 wheat genotypes can be grouped into three kinds (A, B and C, respectively) according to their changing trend of the measured indices; (2) A group performed better resistance drought under the condition of treatment level 1, whose activities of anti-oxidative enzymes (POD, SOD, CAT) were higher; (3) B group exhibited stronger anti-drought under treatment level 2, whose activities of anti-oxidative enzymes were higher; (4) C group expressed anti-drought to some extent under treatment level 3, whose activities of anti-oxidative enzymes were stronger, MDA lower; (5) these results demonstrated that different wheat genotypes have different physiological mechanisms to adapt themselves to changing drought stress, whose molecular basis is discrete gene expression profiling (transcriptom); (6) our results also showed that the concept and method accepted and adopted by most researchers that 75% FC is a proper supply for higher plants - was doubted because this level could not reflect the true suitable level of different wheat genotypes; (7) our research can provide insights into physiological mechanisms of crop anti-drought and direct practical materials for wheat anti-drought breeding; (8) POD, SOD and CAT activities of different wheat genotypes had quite different changing trend at different stages and under different soil water stress conditions, which was linked with their origin of cultivation and individual soil water stress threshold; (9) our primary results also firstly displayed that the changing trend for wheat adapting to environmental stress during life circle was an S-shaped curve, which is, by chance, consistent with Plant Growth Grand Periodicity Curve. (C) 2005 Elsevier B.V. All rights reserved.
A cosmogenic nuclide chronology of the last glacial transition in North-West Nelson, New Zealand - New insights in Southern Hemisphere climate forcing during the last deglaciation
Shulmeister, J Fink, D Augustinus, PC
EARTH AND PLANETARY SCIENCE LETTERS 233:3-4 455-466
We present a new glacial chronology for the last glacial interglacial transition, c. 20 to 10 ka, from the Cobb Valley, NW Nelson, New Zealand, based on a suite of Be-10 and Al-26 cosmogenic exposure ages. This chronology describes one of the most comprehensive deglaciation sequences from a late Quaternary valley system in the Southern Hemisphere. We chronicle the decay from the last (local) glacial maximum as follows: onset of the last deglaciation that commenced no earlier than 18-19 ka, followed by numerous short-term still-stands and/or minor re-advances over the ensuing 3-4 kyr, and complete evacuation of ice by 14 ka. We find no evidence to indicate a late glacial re-advance commensurate with the Northern Hemisphere Younger Dryas chronozone. The absence of a major glacial re-advance in this valley during the latter stages of the last glacial interglacial transition (LGIT) precludes a thermal decline in excess of about 3 degrees C and suggests no decline. The absence of late LGIT re-advances in the mountains of North-West Nelson, while deglacial readvances occurred in the main ranges of the Southern Alps can be best explained if westerly wind forcing rather than large-scale thermal decline is the primary control on glacier fluctuations, at least during the deglaciation. These findings challenge models of global climate change predicated on synchrony of millennial-scale glacial transitions due to thermal changes between Northern and Southern Hemispheres. (C) 2005 Elsevier B.V, All rights reserved.
Changes of anti-oxidative enzymes and membrane peroxidation for soil water deficits among 10 wheat genotypes at seedling
Shao, HB Liang, ZS Shao, MA Wang, BC
COLLOIDS AND SURFACES B-BIOINTERFACES 42:2 107-113
Drought is one of the major factors limiting crop production globally, with increasing global climate change making the situation more serious. Wheat is the staple food for more than 35% of world population, so wheat anti-drought physiology study is of importance to wheat production and biological breeding for the sake of coping with abiotic and biotic conditions. Much research is involved in this hot topic, but the pace of progress is not so large because of drought resistance being a multiple-gene-control quantitative character and wheat genome being larger (16,000 Mb). On the other hand, stress adaptive mechanisms are quite different, with stress degree, time course, materials, and experimental plots, thus increasing the complexity of the issue in question. Additionally, a little study is related to the whole life circle of wheat, which cannot provide a comprehensive understanding of its anti-drought machinery. We selected 10 kinds of wheat genotypes as materials, which have potential to be applied in practice, and measured relative change of anti-oxidative enzymes and membrane peroxidation through wheat whole growth-developmental circle (i.e. seedling, tillering and maturing). Here, we firstly reported the results of seedling stage as follows: (1) 10 wheat genotypes can be grouped into three kinds (A-C, respectively) according to their changing trend of the measured indices; (2) A performed better resistance drought under the condition of treatment level 1 (appropriate level), whose activities of anti-oxidative enzymes (POD, SOD, CAT) were higher and MDA lower and chlorophyll a + b higher; (3) B exhibited stronger anti-drought under treatment level 2 (light stress level), whose activities of anti-oxidative enzymes were higher, MDA lower and chlorophyll higher; (4) C expressed anti-drought to some extent under treatment level 3 (serious stress), whose activities of anti-oxidative enzymes were stronger, MDA lower and chlorophyll higher; (5) these results demonstrated that different wheat genotypes have different physiological mechanisms to adapt themselves to changing drought stress, whose molecular basis is discrete gene expression profiling (transcriptom); (6) our results also showed that the concept accepted by most researchers, 70-75% QF [T.C. Hsiao, Plant responses to water stress, Ann. Rev. Plant Physiol. 24 (1973) 519-570] is a proper supply for plants, was doubted, because this level could not reflect the true suitable level of wheat. The study in this respect is the key to wheat anti-drought and biological saving-water; (7) our research can provide insights into physiological mechanisms of crop anti-drought and direct practical materials for wheat anti-drought breeding. © 2005 Elsevier B.V. All rights reserved.
Year-round measurements of net ecosystem CO2 flux over a montane larch forest in Mongolia
Li, SG Asanuma, J Kotani, A Eugster, W Davaa, G Oyunbaatar, D Sugita, M
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 110:D9 -
Mongolian boreal forest merits special attention since it is located in the transitional area between the southern Siberian boreal forest and the Asian steppe zone, a vulnerable region being potentially affected by global warming and anthropogenic activities. This paper presents the first full-year-long continuous measurements of net ecosystem CO2 flux (NEE) made over a montane larch (Larix sibirica Ledeb.) forest in Mongolia from 25 March 2003 to 24 March 2004 (366 days) using the eddy covariance technique. The hourly maximum uptake was -10.1 μ mol m(-2) s(-1). The maximum daily uptake of -4.0 g C m(-2) d(-1) (negative NEE values denote net carbon uptake by the canopy from the atmosphere) occurred in July. The annual cumulative NEE was -85 g C m(-2), indicating that the forest acted as a net sink of CO2. We examined the responses of NEE to environmental conditions in the growing season from May to September. Both daytime 30-min mean and daily integrated NEE responded to incident photosynthetically active radiation (PAR) in a rectangular hyperbolic fashion. Model results show that the apparent quantum yield (α) was -0.0133 &PLUSMN; 0.0011 mmol CO2 per μ mol of photons, and the bulk light use efficiency (LUE) on the daily basis was -6.7 mmol CO2 per mole of PAR photons over the entire growing season for this forest. Additionally, daily integrated NEE was also a linear function of the normalized difference vegetation index (NDVI), a linear function of mean daily air temperature (T-a), and a quadratic polynomial function of daily means of the atmospheric water vapor pressure deficit (VPD). Among these factors, LAI (as measured by NDVI) was dominant in affecting the dynamics of NEE, followed by T-a. Lower T-a was limiting the growth rate of this montane larch forest. As daily means of VPD exceeded 1.2 kPa, net CO2 uptake by the canopy declined. Nevertheless, water stress was not observed as a problem for the forest growth.
Latitudinal gradients of parasite species richness in primates
Nunn, CL Altizer, SM Sechrest, W Cunningham, AA
DIVERSITY AND DISTRIBUTIONS 11:3 249-256
Infectious disease risk is thought to increase in the tropics, but little is known about latitudinal gradients of parasite diversity. We used a comparative data set encompassing 330 parasite species reported from 119 primate hosts to examine latitudinal gradients in the diversity of micro and macroparasites per primate host species. Analyses conducted with and without controlling for host phylogeny showed that parasite species richness increased closer to the equator for protozoan parasites, but not for viruses or helminths. Relative to other major parasite groups, protozoa reported from wild primates were transmitted disproportionately by arthropod vectors. Within the protozoa, our results revealed that vector-borne parasites showed a highly significant latitudinal gradient in species richness. This higher diversity of vector-borne protozoa near the tropics could be influenced by a greater abundance or diversity of biting arthropods in the tropics, or by climatic effects on vector behaviour and parasite development. Many vector-borne diseases, such as leishmaniasis, trypanosomiasis, and malaria pose risks to both humans and wildlife, and nearly one-third of the protozoan parasites from free-living primates in our data set have been reported to infect humans. Because the geographical distribution and prevalence of many vector-borne parasites are expected to increase because of global warming, these results are important for predicting future parasite-mediated threats to biodiversity and human health.
Economic reform, energy, and development: the case of Mexican manufacturing
Aguayo, F Gallagher, KP
ENERGY POLICY 33:7 829-837
Given increasing concern over global climate change and national security there is a burgeoning interest in examining the relationship between economic growth and energy use in developed and developing countries. More specifically, decoupling energy use per unit of gross domestic product (GDP) has fast come to be seen as in the interests of national economies and the world as a whole. Recent attention has been paid to the dramatic decreases in the energy intensity of the Chinese economy, which fell by 55% between 1975 and 1995. Do other developing economies follow similar trajectories? This paper examines the energy intensity of the Mexican economy for the period 1988-1998. Although the long-term trend in Mexican energy intensity is rising, the energy intensity of the Mexican economy began to decline in 1988. This paper explores the factors that have contributed to this reduction. Diminishing Mexican energy use per unit of GDP has been driven by significant decreases in industrial energy intensity. We show that these changes have resulted from changes in the composition of Mexican industrial structure and technological change. (C) 2003 Elsevier Ltd. All rights reserved.
World crop residues production and implications of its use as a biofuel
ENVIRONMENT INTERNATIONAL 31:4 575-584
Reducing and off-setting anthropogenic emissions of CO, and other greenhouse gases (GHGs) are important strategies of mitigating the greenhouse effect. Thus, the need for developing carbon (C) neutral and renewable sources of energy is more than ever before. Use of crop residue as a possible source of feedstock for bioenergy production must be critically and objectively assessed because of its positive impact on soil C sequestration.. soil quality maintenance and ecosystem functions. The amount of crop residue produced in the US is estimated at 367x10(6) Mg/year for 9 cereal crops, 450x10(6) Mg/year for 14 cereals and legumes, and 488x10(6) Mg/year for 21 crops. The amount of crop residue produced in the world is estimated at 2802x10(6) Mg/year for cereal crops, 3107x10(6) Mg/year for 17 cereals and legumes, and 3758x10(6) Mg/year for 27 food crops. The fuel value of the total annual residue produced is estimated at 1.5x10(15) kcal, about I billion barrels (bbl) of diesel equivalent, or about 8 quads for the US; and 11.3x10(15) kcal, about 7.5 billion bbl of diesel or 60 quads for the world. However, even a partial removal (30-40%) of crop residue from land can exacerbate soil erosion hazard, deplete the SOC pool, accentuate emission of CO, and other GHGs from soil to the atmosphere, and exacerbate the risks of global climate change. Therefore, establishing bioenergy plantations of site-specific species with potential of producing 10-15 Mg biomass/year is an option that needs to be considered. This option will require 40-60 million hectares of land in the US and about 250 million hectares worldwide to establish bioenergy plantations. (c) 2004 Elsevier Ltd. All rights reserved.
Synthesis of industrial utility systems: cost-effective de-carbonisation
Varbanov, P Perry, S Klemes, J Smith, R
APPLIED THERMAL ENGINEERING 25:7 985-1001
The production processes on industrial sites require large amounts of heating, cooling and power for their operation. Therefore, the optimal synthesis of utility systems is of central interest to engineers in the process industries. Recently, the problem of the global climate change has brought forward the question of reducing significantly the emissions of greenhouse gases into the atmosphere. In this paper, a new approach is presented for cost-effective de-carbonisation of new utility systems in the process industries. This is based on improved models of utility equipment components and an improved model and procedure for optimal synthesis of utility systems. (C) 2004 Elsevier Ltd. All rights reserved.
Linkage mapping of osmotic stress induced genes of oak
Porth, I Scotti-Saintagne, C Barreneche, T Kremer, A Burg, K
TREE GENETICS & GENOMES 1:1 31-40
Water stress affecting long-lived trees is an important challenge in forestry. Due to global climate change, forest trees will be threatened by extreme conditions like flooding or drought. It is necessary to understand differences in stress tolerance within certain species and to investigate putative relations on genomic level. In this study, osmotic stress induced genes of Quercus ssp. were positioned on two genetic linkage maps of oak. An intra-specific cross 3P*A4 of Quercus robur consisting of 88 offspring and an inter-specific cross 11P*QS29 of Q. robur and Q. petraea comprising 72 full-sibs were analyzed for the inheritance of 14 loci represented by 34 individual single nucleotide polymorphisms. Seven genes in the intra-cross, as well as other six genes in the inter-cross could be mapped and one gene could not be localised due to the severe distortion of the segregation. The collection of expressed sequences involved ribosomal proteins, members of the oxylase/oxygenase gene family, betaine aldehyde dehydrogenase, Dc3 promoter-binding factor, a putative member of the nodulin family, glutathione-S-transferase and proteins with unknown functions. In the inter-cross, two linked markers exhibited 89% deficiency of heterozygosity. Thirteen genes were positioned on ten different oak chromosomes and can serve as orthologous markers in comparative mapping studies within Fagaceae.
Impacts of flooding and climate change on urban transportation: A systemwide performance assessment of the Boston Metro Area
Suarez, P Anderson, W Mahal, V Lakshmanan, TR
TRANSPORTATION RESEARCH PART D-TRANSPORT AND ENVIRONMENT 10:3 231-244
Global climate change is likely to affect urban infrastructure through sea level rise and increased frequency of extreme events. This paper assesses the potential impact of climate change on the system-wide performance of transportation networks using the Boston Metro Area as a case study. The methodology integrates projected changes in land use, demographic and climatic conditions into the urban transportation modeling system in order to explore the relative impacts of global warming on the system performance due to additional riverine and coastal flooding. Results indicate almost a doubling in delays and lost trips. These impacts are significant, but probably not large enough to justify a major effort for adapting the physical infrastructure to expected climatic conditions, except for some key links. (c) 2005 Elsevier Ltd. All rights reserved.
Carbon cycling and budget in a forested basin of southwestern Hokkaido, northern Japan
Shibata, H Hiura, T Tanaka, Y Takagi, K Koike, T
ECOLOGICAL RESEARCH 20:3 325-331
Quantification of annual carbon sequestration is very important in order to assess the function of forest ecosystems in combatting global climate change and the ecosystem responses to those changes. Annual cycling and budget of carbon in a forested basin was investigated to quantify the carbon sequestration of a cool-temperate deciduous forest ecosystem in the Horonai stream basin, Tomakomai Experimental Forest, northern Japan. Net ecosystem exchange, soil respiration, biomass increment, litterfall, soil-solution chemistry, and stream export were observed in the basin from 1999-2001 as a part of IGBP-TEMA project. We found that 258 g C m(-2) year(-1) was sequestered annually as net ecosystem exchange (NEE) in the forested basin. Discharge of carbon to the stream was 4 g C m(-2) year(-1) (about 2% of NEE) and consisted mainly of dissolved inorganic carbon (DIC). About 43% of net ecosystem productivity (NEP) was retained in the vegetation, while about 57% of NEP was sequestered in soil, suggesting that the movement of sequestered carbon from above-ground to belowground vegetation was an important process for net carbon accumulation in soil. The derived organic carbon from aboveground vegetation that moved to the soil mainly accumulated in the solid phase of the soil, with the result that the export of dissolved organic carbon to the stream was smaller than that of dissolved inorganic carbon. Our results indicated that the aboveground and belowground interaction of carbon fluxes was an important process for determining the rate and retention time of the carbon sequestration in a cool-temperate deciduous forest ecosystem in the southwestern part of Hokkaido, northern Japan.
A method for estimating vulnerability of Douglas-fir growth to climate change in the northwestern US
Littell, JS Peterson, DL
FORESTRY CHRONICLE 81:3 369-374
Borrowing from landscape ecology, atmospheric science, and integrated assessment, we aim to understand the complex interactions that determine productivity in montane forests and utilize such relationships to forecast montane forest vulnerability under global climate change. Specifically, we identify, relationships for precipitation and temperature that govern the spatiotemporal variability in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) growth by seeking similarities in patterns of growth/climate models across a significant portion of the climatological range of the species. In the 21(st) century and beyond, sustainable forestry will depend on successful adaptation to the impacts of climate change and climate variability on forest structure and function. The combination of these foci will allow improved prediction of the fate of montane forests over a wide range of biogeoclimatic conditions in western North America and thus allow improved management strategies for adapting to climate change. We describe a multi-disciplinary strategy for analyzing growth variability as a function of climate over a broad range of local-to-regional influences and demonstrate the efficacy of this sampling method in defining regional gradients of growth-limiting factors.
Trends in twentieth-century tree growth at high elevations in the Sierra Nevada and White Mountains, USA
Bunn, AG Graumlich, LJ Urban, DL
HOLOCENE 15:4 481-488
We analysed a multispecies tree-ring data base to assess the degree to which twentieth-century growth trends reflect tree growth of the last millennium. We examined similar to 1000-yr chronologies for five species of high-elevation conifers at 13 sites in western North America. Using non-parametric ordination and cluster analysis, we decomposed the variability at annual to decadal timescales into two dimensions, both of which are significantly correlated to temperature and precipitation variation. Tree-ring sites map onto the ordination axes according to species and relative position on the landscape. A spectral analysis of the ordination axes indicates a secular trend and significant quasi-periodic variation on scales of years to decades. Further, we find that the pattern of high-elevation conifer growth rates during the last half of the twentieth century are different than any time in the past 1000 years, indicating a distinct biological signature of global climate change.
Polychaete (Spirobranchus giganteus) loading on South African corals
Floros, CD Samways, MJ Armstrong, B
AQUATIC CONSERVATION-MARINE AND FRESHWATER ECOSYSTEMS 15:3 289-298
1. Spirobranchus giganteus is a ubiquitous serpulid polychaete that is an obligate associate of living coral. At Sodwana Bay, South Africa, it is a conspicuous associate of Acropora clathrata plates. 2. This study explores the relationship between S. giganteus abundance and factors hypothesized to represent stress to the corals, in particular coral bleaching, diving intensity and exposure to destructive wave action as a function of depth. In addition, plate size was investigated to increase understanding of habitat selection by S. giganteus. 3. There was no significant correlation between diving intensity and S. giganteus abundance on the three reefs studied, suggesting either that the current level of diving intensity causes no stress or that S. giganteus does not indicate stress. 4. Depth influenced the size distribution of A. clathrata plates, with the larger plates being at greatest depths ( > 0.4 m(2) at depths > 14 m). 5. Extremely high S. giganteus densities 2 (most plates with number of individuals > 50 m(-2), maximum number of individuals 413.63 m(-2) at 9m depth on one reef) were recorded at depths > 14m, with density increasing overall with depth. 6. The high densities of S. giganteus on A. clathrata plates are possibly because the plates are a physically elevated platform above the reef, where factors such as predation, competition and smothering by sand are far less important than on the reef surface. In turn, upwelling of nutrients and dependent plankton may encourage S. giganteus to maintain high population levels. 7. Climatic or other stresses are not considered currently to be responsible for these high S. giganteus densities. Rather, the worm data reflect a healthy upwelling, which may change as the coral reef becomes stressed with global climate change. Copyright (c) 2005 John Wiley & Sons, Ltd.
The costs of mitigating carbon emissions in China: findings from China MARKAL-MACRO modeling
ENERGY POLICY 33:7 885-896
In this paper MARKAL-MACRO, an integrated energy-environment-economy model, is used to generate China’s reference scenario for future energy development and carbon emission through the year 2050. The results show that with great efforts on structure adjustment, energy efficiency improvement and energy substitution, China’s primary energy consumption is expected to be 4818 Mtce and carbon emission 2394 MtC by 2050 with annual decrease rate of 3% for the carbon intensity per GDP during the period 2000-2050. On the basis of this reference scenario, China’s marginal abatement cost curves of carbon for the year 2010, 2020 and 2030 are derived from the model, and the impacts of carbon emission abatement on GDP are also simulated. The results are compared with those from other sources. The research shows that the marginal abatement costs vary from 12USS/tC to 216USS/tC and the rates of GDP losses relative to reference range from 0.1% to 2.54% for the reduction rates between 5% and 45%. Both the marginal abatement costs and the rates of GDP losses further enlarge on condition that the maximum capacity of nuclear power is constrained to 240GW or 160GW by 2050. The paper concludes that China’s costs of carbon abatement is rather high in case of carbon emissions are further cut beyond the reference scenario, and China’s carbon abatement room is limited due to her coal-dominant energy resource characteristic. As economic development still remains the priority and per capita income as well as per capita carbon emission are far below the world average, it will be more realistic for China to make continuous contribution to combating global climate change by implementing sustainable development strategy domestically and playing an active role in the international carbon mitigation cooperation mechanisms rather than accepting a carbon emission ceiling. (C) 2003 Elsevier Ltd. All rights reserved.
A South American bioinvasion case history: Limnoperna fortunei (Dunker, 1857), the golden mussel
Darrigran, G Damborenea, C
AMERICAN MALACOLOGICAL BULLETIN 20:1-2 105-112
Two factors combine in this age of globalization to favor the establishment of alien species in natural environments: human activities and global climate change. This paper reviews the recent invasion of the golden mussel, Limnoperna fortunei, in South America, including its impacts in natural and human environments. This case study allows the identification of the likely impacts that morphologically and functionally similar invasive species will have in similar environments, such as in North America, which is considered to be at high risk of invasion by L. fortunei.
Large temperature variability in the southern African tropics since the Last Glacial Maximum
Powers, LA Johnson, TC Werne, JP Castanada, IS Hopmans, EC Damste, JSS Schouten, S
GEOPHYSICAL RESEARCH LETTERS 32:8 -
The role of the tropics in global climate change is actively debated, particularly in regard to the timing and magnitude of thermal and hydrological response. Continuous, high-resolution temperature records through the Last Glacial Maximum (LGM) from tropical oceans have provided much insight but surface temperature reconstructions do not exist from tropical continental environments. Here we used the TEX86 paleotemperature proxy to reconstruct mean annual lake surface temperatures through the Last Glacial Maximum (LGM) in Lake Malawi, East Africa (9&DEG;-14&DEG; S). We find a &SIM; 3.5&DEG; C overall warming since the LGM, with temperature reversals of &SIM; 2&DEG; C during the Younger Dryas (12.5 ka BP) and at 8.2 ka BP. Maximum Holocene temperatures of &SIM; 29&DEG; C were found at 5 ka BP, a period preceding severe drought in Africa. These results suggest a substantial thermal response of southeastern tropical Africa to deglaciation and to varying conditions during the Holocene.
Origin of the highly elevated Pyrenean peneplain
Babault, J Van den Driessche, J Bonnet, S Castelltort, S Crave, A
TECTONICS 24:2 -
 Peneplanation of mountain ranges is generally considered the result of long-term erosional processes that smooth relief and lower elevation near sea level. Therefore peneplain remnants at high elevation in mountain ranges are used to infer posttectonic surface uplift. Such an interpretation has been proposed for the Pyrenees where high-elevation, low-relief erosional surfaces rose up to more than 2000 m. Because the Pyrenean foreland basins are filled with very thick continental deposits, which have buried the early jagged landscape, we challenge this hypothesis by pointing out that relief applanation does not necessarily require elevation lowering. We propose an alternative interpretation in which piedmont aggradation of detrital sediment that comes from erosion of the high chain induces the rise of the base level of the range, therefore reducing strongly the erosive efficiency of the drainage system and resulting in the progressive smoothing of the relief. Such a process allows a high-elevation, low-relief erosional surface to develop at the scale of the range. In the Pyrenees, occurrence of high-elevation, low-relief erosional surface remnants does not imply a posttectonic uplift, but is instead due to the dissection of the initial Miocene high-elevation, low-relief surface by the recent drainage system, the erosive activity of which has been enhanced by global climate change from the late Pliocene onward.
Sustainability-guided promotion of renewable electricity generation
Madlener, R Stagl, S
ECOLOGICAL ECONOMICS 53:2 147-167
in recent years, the threat of global climate change, high fuel import dependence, and rapidly rising electricity demand levels have intensified the quest for more sustainable energy systems. This in turn has increased the need for policy makers to promote electricity generation from renewable energy sources. Guaranteed prices coupled with a buy-back obligation for electricity fed into the grid is a popular renewables promotion instrument, especially in Europe. More recently, driven mainly by electricity market liberalisation efforts, quota targets for the share of renewables in combination with tradable ‘green’ certificates (TGC) have received considerable attention. TGC offer a greater theoretical potential for economic efficiency gains, due to price competition and the greater flexibility assigned to the obliged parties. While guaranteed prices and TGC schemes support the operation of renewable energy technology systems, bidding schemes for renewable energy generation capacity are used to raise economic efficiency on the plant construction side. All of these policy instruments suffer from the shortcoming that they do not explicitly account for the often widely varying environmental, social and economic impacts of the technologies concerned. In this paper, we propose a methodology for the design of renewable energy policy instruments that is based on integrated assessment. In particular, we argue that using participatory multicriteria evaluation as part of the design of renewable energy promotion policies would make it possible: (1) to differentiate the level of promotion in a systematic and transparent manner according to their socio-ecological economic impact, and (2) to explicitly account for the preferences of stakeholders. A further problem of existing TGC and bidding schemes is that diversity of supply could be severely diminished, if few low-cost technologies were allowed to dominate the renewable energy market. To ensure a certain diversity of technologies, our scheme suggests the use of different technology bands for technologies that are relatively homogeneous with respect to their maturity. (c) 2004 Elsevier B.V. All rights reserved.
Implications of global climatic change and energy cost and availability for the restoration of the Mississippi delta
Day, JW Barras, J Clairain, E Johnston, J Justic, D Kemp, GP Ko, JY Lane, R Mitsch, WJ Steyer, G Templet, P Yanez-Arancibia, A
ECOLOGICAL ENGINEERING 24:4 253-265
Over the past several thousand years, inputs from the Mississippi River formed the Mississippi delta, an area of about 25,000 km(2). Over the past century, however, there has been a high loss of coastal wetlands of about 4800 km(2). The main causes of this loss are the near complete isolation of the river from the delta, mostly due to the construction of flood control levees, and pervasive hydrological disruption of the deltaic plain. There is presently a large-scale State-Federal program to restore the delta that includes construction of water control structures in the flood control levees to divert river water into deteriorating wetlands and pumping of dredged sediment, often for long distances, for marsh creation. Global climate change and decreasing availability and increasing cost of energy are likely to have important implications for delta restoration. Coastal restoration efforts will have to be more intensive to offset the impacts of climate change including accelerated sea level rise and changes in precipitation patterns. Future coastal restoration efforts should also focus on less energy-intensive, ecologically engineered management techniques that use the energies of nature as much as possible. Diversions may be as important for controlling salinity as for providing sediments and nutrients for restoring coastal wetlands. Energy-intensive pumping-dredged sediments for coastal restoration will likely become much more expensive in the future. (c) 2005 Elsevier B.V. All rights reserved.
Multi-scale observation and cross-scale mechanistic modeling on terrestrial ecosystem carbon cycle
Cao, MK Yu, GR Liu, JY Li, KR
SCIENCE IN CHINA SERIES D-EARTH SCIENCES 48: Suppl. 1 17-32
To predict global climate change and to implement the Kyoto Protocol for stabilizing atmospheric greenhouse gases concentrations require quantifying spatio-temporal variations in the terrestrial carbon sink accurately. During the past decade multi-scale ecological experiment and observation networks have been established using various new technologies (e.g. controlled environmental facilities, eddy covariance techniques and quantitative remote sensing), and have obtained a large amount of data about terrestrial ecosystem carbon cycle. However, uncertainties in the magnitude and spatio-temporal variations of the terrestrial carbon sink and in understanding the underlying mechanisms have not been reduced significantly. One of the major reasons is that the observations and experiments were conducted at individual scales independently, but it is the interactions of factors and processes at different scales that determine the dynamics of the terrestrial carbon sink. Since experiments and observations are always conducted at specific scales, to understand cross-scale interactions requires mechanistic analysis that is best to be achieved by mechanistic modeling. However, mechanistic ecosystem models are mainly based on data from single-scale experiments and observations and hence have no capacity to simulate mechanistic cross-scale interconnection and interactions of ecosystem processes. New-generation mechanistic ecosystem models based on new ecological theoretical framework are needed to quantify the mechanisms from micro-level fast eco-physiological responses to macro-level slow acclimation in the pattern and structure in disturbed ecosystems. Multi-scale data-model fusion is a recently emerging approach to assimilate multi-scale observational data into mechanistic, dynamic modeling, in which the structure and parameters of mechanistic models for simulating cross-scale interactions are optimized using multi-scale observational data. The models are validated and evaluated at different spatial and temporal scales and real-time observational data are assimilated continuously into dynamic modeling for predicting and forecasting ecosystem changes realistically. In summary, a breakthrough in terrestrial carbon sink research requires using approaches of multi-scale observations and cross-scale modeling to understand and quantify interconnections and interactions among ecosystem processes at different scales and their controls over ecosystem carbon cycle.
Leaf mineral nutrition of Arctic plants in response to warming and deeper snow in northern Alaska
Welker, JM Fahnestock, JT Sullivan, PF Chimner, RA
OIKOS 109:1 167-177
Articulating the consequences of global climate change on terrestrial ecosystem biogeochemistry is a critical component of Arctic system studies. Leaf mineral nutrition responses of tundra plants is an important measure of changes in organismic and ecosystem attributes because leaf nitrogen and carbon contents effect photosynthesis, primary production, carbon budgets, leaf litter, and soil organic matter decomposition as well as herbivore forage quality. In this study, we used a long term experiment where snow depth and summer temperatures were increased independently and together to articulate how a series of climate change scenarios would affect leaf N, leaf C, and leaf C: N for vegetation in dry and moist tussock tundra in northern Alaska, USA. Our findings were: 1) moist tundra vegetation is much more responsive to this suite of climate change scenarios than dry tundra with up to a 25% increase in leaf N; 2) life forms exhibit divergence in leaf C, N, and C:N with deciduous shrubs and graminoids having almost identical leaf N contents; 3) for some species, leaf mineral nutrition responses to these climate change scenarios are tundra type dependent (Betula), but for others (Vaccinium vitis-idaea), strong responses are exhibited regardless of tundra type; and 4) the seasonal patterns and magnitudes of leaf C and leaf N in deciduous and evergreen shrubs were responsive to conditions of deeper snow in winter. Leaf N is was generally higher immediately after emergence from the deep snow experimental treatments and leaf N was higher during the subsequent summer and fall, and the leaf C:N were lower, especially in deciduous shrubs. These findings indicate that coupled increases in snow depth and warmer summer temperatures will alter the magnitudes and patterns of leaf mineral nutrition and that the longterm consequences of these changes may feed-forward and affect ecosystem processes.
Gaia’s breath - global methane exhalations
Kvenvolden, KA Rogers, BW
MARINE AND PETROLEUM GEOLOGY 22:4 579-590
Methane (CH4) is the most abundant organic compound in the Earth’s atmosphere, where it acts as a greenhouse gas and thus has implications for global climate change. The current atmospheric CH4 budget, however, does not take into account geologically-sourced CH4 seepage. Geological sources of CH4 include natural macro- and micro-seeps, mud volcanoes, and other miscellaneous sources such as gas hydrates, magmatic volcanoes, geothermal regions, and mid-ocean ridges. Macro-seeps contribute similar to 25 Tg (teragrams) CH4/yr to the atmosphere, whereas, micro-seepage contributes perhaps 7 Tg CH4/yr. Mud volcanoes emit similar to 5 Tg CH4/yr, and miscellaneous sources emit similar to 8 Tg CH4/yr to the atmosphere. Thus, the total contribution to the atmosphere from geological sources is estimated to be 45 Tg CH4/yr, which is significant to the atmospheric organic carbon cycle and should be included in any global inventory of atmospheric CH4. We argue that the atmospheric CH4 global inventory of the Interplanetary Panel on Climate Change must be adjusted in order to incorporate geologically-sourced CH4 from naturally occurring seepage. Published by Elsevier Ltd.
Denitrification and N2O emission from forested and cultivated alluvial clay soil
Ullah, S Breitenbeck, GA Faulkner, SP
BIOGEOCHEMISTRY 73:3 499-513
Restored forested wetlands reduce N loads in surface discharge through plant uptake and denitrification. While removal of reactive N reduces impact on receiving waters, it is unclear whether enhanced denitrification also enhances emissions of the ‘greenhouse’ gas N2O, thus compromising the water-quality benefits of restoration. This Study compares denitrification rates and N2O:N-2 emission ratios from Sharkey clay soil in a mature bottomland forest to those from all adjacent cultivated site in the Lower Mississippi Alluvial Valley. Potential denitrification of forested soil was 2.4 times of cultivated soil. Using intact soil cores, denitrification rates of forested soil were 5.2, 6.6 and 2.0 times those of cultivated soil at 70, 85 and 100% water-filled pore space (WFPS), respectively. When NO3 was added, N2O emissions from forested soil were 2.2 times those of cultivated soil at 70% WFPS. At 85 and 100% WFPS, N2O emissions were not significantly different despite much greater denitrification rates in the forested soil because N2O:N-2 emission ratios declined more rapidly in forested soil as WFPS increased. These findings suggest that restoration of forested wetlands to reduce NO3 in surface discharge will not contribute significantly to the atmospheric burden of N2O.
Coevolution and biogeography among Nematodirinae (Nematoda : Trichostrongylina) Lagomorpha and Artiodactyla (Mammalia): Exploring determinants of history and structure for the northern fauna across the Holarctic
JOURNAL OF PARASITOLOGY 91:2 358-369
Nematodes of the subfamily Nematodirinae are characteristic components of a Holarctic fauna. The topology of a generic-level phylogenetic hypothesis, patterns of diversity. and geographic distributions for respective nematode taxa in conjunction with data for host occurrence are consistent with primary distributions determined across Beringia for species of Murielus, Rauschia, Nematodirus, and Nematodirella. Ancestral hosts are represented by Lagomorpha, with evidence for a minimum of 1 host-switching-event and subsequent radiation in the Artiodactyla. Diversification may reflect vicariance of respective faunas along with episodic or cyclical range expansion and isolation across Beringia during the late Tertiary and Quaternary. Secondarily, species of Nematodirus attained a distribution in the Neotropical region with minimal diversification of an endemic fauna represented by Nematodirus molini among tayassuids, Nematodirus lamae among camelids and Nematodirus urichi in cervids during the Pleistocene. Nematodirines are a core component of an Arctic-Boreal fauna of zooparasitic nematodes (defined by latitude and altitude) adapted to transmission in extreme environments characterized by seasonally low temperatures and varying degrees of desiccation. The history and distribution of this fauna is examined in the context of biotic and abiotic determinants for geographic colonization and host switching with an exploration of predicted responses of complex host-parasite systems to ecological perturbation under a regime of global climate change.
Variation in leaf litter nutrients of a Costa Rican rain forest is related to precipitation
Wood, TE Lawrence, D Clark, DA
BIOGEOCHEMISTRY 73:2 417-437
By assessing current leaf litter nutrient dynamics, we may be able to predict responses of nutrient cycling in tropical ecosystems to future environmental change. The goal of this study was to assess whether nutrient cycling is related to seasonal variation in rainfall in a wet tropical forest. We examined leaf litter of an old-growth tropical rain forest in N.E. Costa Rica over a 4-year period to explore seasonal and inter-annual changes in leaf litter nutrient concentrations, and to evaluate potential short- and long-term drivers of variation in litter nutrient concentration, particularly that of phosphorus (P) and nitrogen (N). We also examined the temporal dynamics of calcium, potassium, and magnesium in the leaf litter. Leaf litter [P] and %N changed significantly with time, both seasonally and inter-annually. Seasonal changes in leaf litter [P] were strongly positively correlated with rainfall from the previous 2 weeks; cations, however, were inversely related to this measure of current rainfall, while %N was not related to rainfall. We propose that the positive relationship between current rainfall and leaf litter [P] is due to a response by the vegetation to an increase in nutrient availability and uptake. In contrast, given the negative relationship between current rainfall and cation concentrations, leaching from live leaf tissue is a more likely driver of short-term changes in cations. Should global climate change include altered rainfall patterns in this biome, one class of ecosystem-level responses could be significant changes in P and cation cycling.
Improved scheme for determining the thermal centroid of the oceanic warm pool using sea surface temperature data
Chen, G Fang, LX
JOURNAL OF OCEANOGRAPHY 61:2 295-299
During the past two decades, concern about the western Pacific Warm Pool (WP) has been growing following the recognition of its significant role in global climate change and its close association with El Nino-Southern Oscillation phenomena. A fundamental issue in WP related studies is to locate its centroid and track its trajectory. The method used by some previous researchers for estimating the WP position seems to oversimplify the problem to a purely geometric one. This, however, is found to be systematically biased in both zonal and meridional directions. A new scheme for determining the WP centroid, which takes into account the thermal structure of the surface water, is proposed, resulting in a significant improvement in precise tracking of the WP trajectory compared to previous results.
Decomposition of soybean grown under elevated concentrations of CO2 and O-3
Booker, FL Prior, SA Torbert, HA Fiscus, EL Pursley, WA Hu, SJ
GLOBAL CHANGE BIOLOGY 11:4 685-698
A critical global climate change issue is how increasing concentrations of atmospheric CO2 and ground-level O-3 will affect agricultural productivity. This includes effects on decomposition of residues left in the field and availability of mineral nutrients to subsequent crops. To address questions about decomposition processes, a 2-year experiment was conducted to determine the chemistry and decomposition rate of aboveground residues of soybean (Glycine max (L.) Merr.) grown under reciprocal combinations of low and high concentrations of CO2 and O-3 in open-top field chambers. The CO2 treatments were ambient (370 mu mol mol(-1)) and elevated (714 mu mol mol(-1)) levels (daytime 12 h averages). Ozone treatments were charcoal-filtered air (21 nmol mol(-1)) and nonfiltered air plus 1.5 times ambient O-3 (74 nmol mol(-1)) 12 h day(-1). Elevated CO2 increased aboveground postharvest residue production by 28-56% while elevated O-3 suppressed it by 15-46%. In combination, inhibitory effects of added O-3 on biomass production were largely negated by elevated CO2. Plant residue chemistry was generally unaffected by elevated CO2, except for an increase in leaf residue lignin concentration. Leaf residues from the elevated O-3 treatments had lower concentrations of nonstructural carbohydrates, but higher N, fiber, and lignin levels. Chemical composition of petiole, stem, and pod husk residues was only marginally affected by the elevated gas treatments. Treatment effects on plant biomass production, however, influenced the content of chemical constituents on an areal basis. Elevated CO2 increased the mass per square meter of nonstructural carbohydrates, phenolics, N, cellulose, and lignin by 24-46%. Elevated O-3 decreased the mass per square meter of these constituents by 30-48%, while elevated CO2 largely ameliorated the added O-3 effect. Carbon mineralization rates of component residues from the elevated gas treatments were not significantly different from the control. However, N immobilization increased in soils containing petiole and stem residues from the elevated CO2, O-3, and combined gas treatments. Mass loss of decomposing leaf residue from the added O-3 and combined gas treatments was 48% less than the control treatment after 20 weeks, while differences in decomposition of petiole, stem, and husk residues among treatments were minor. Decreased decomposition of leaf residues was correlated with lower starch and higher lignin levels. However, leaf residues only comprised about 20% of the total residue biomass assayed so treatment effects on mass loss of total aboveground residues were relatively small. The primary influence of elevated atmospheric CO2 and O-3 concentrations on decomposition processes is apt to arise from effects on residue mass input, which is increased by elevated CO2 and suppressed by O-3.
Surface air temperature variability over Turkey and its connection to large-scale upper air circulation via multivariate techniques
Tatli, H Dalfes, HN Mentes, SS
INTERNATIONAL JOURNAL OF CLIMATOLOGY 25:3 331-350
The problem of statistical linkages between large-scale and local-scale processes is investigated through noise reduction by singular spectrum analysis (SSA) and spatial principal component analysis in order to construct appropriate statistical models for estimating the local-scale climate variables from large-scale climate processes. This paper presents an approach for downscaling monthly temperature series over Turkey by upper air circulations derived from the National Centers for Environmental Prediction-National Center for Atmospheric Research Reanalysis data sets (500 hPa geopotential heights and 500-1000 hPa thicknesses). The proposed approach consists of three stages. First, the available data sets are separated into deterministic, statistical components and random components by SSA. Second, the deterministic components are saved and the random components are eliminated by spatial principal component analysis. Subsequently, the statistical components are combined with the deterministic components constituting a noise-free data set. Furthermore, so-called Sampson correlation patterns are determined between the noise-free large-scale and the local-scale variables for interpreting the large-scale process impacts on local-scale features. Third, the significant redundancy variates based on canonical correlation analysis are extracted in order to identify the statistical downscaling model for temperature series of 62 stations in Turkey. The results show that the interpretation of the local-scale processes with the noise-free data sets is more significant than with the raw data sets. Copyright (c) 2005 Royal Meteorological Society.
Temperature dependence of carbon-13 kinetic isotope effects of importance to global climate change
Lin, H Zhao, Y Ellingson, BA Pu, JZ Truhlar, DG
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 127:9 2830-2831
Comparison of climate space and phylogeny of Marmota (Mammalia : Rodentia) indicates a connection between evolutionary history and climate preference
PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES 272:1562 519-526
Palaeobiologists have investigated the evolutionary responses of extinct organisms to climate change, and have also used extinct organisms to reconstruct palaeoclimates. There is evidence of a disconnection between climate change and evolution that suggests that organisms may not be accurate palaeoclimate indicators. Here, marmots (Marmota sp.) are used as a case study to examine whether similarity of climate preferences is correlated with evolutionary relatedness of species. This study tests for a relationship between phylogenetic distance and ‘climate distance’ of species within a clade. There should be a significant congruence between maximum likelihood distance and standardized Euclidian distance between climates if daughter species tend to stay in environments similar to parent species. Marmots make a good test case because there are many extant species, their phylogenies are well established and individual survival is linked to climatic factors. A Mantel test indicates a significant correlation between climate and phylogenetic distance matrices, but this relationship explains only a small fraction of the variance (regression R-2 = 0.114). These results suggest that (i) closely related species of marmots tend to stay in similar environments; (ii) marmots may be more susceptible than many mammals to global climate change; and (iii) because of the considerable noise in this system, the correlation cannot be used for detailed palaeoclimate reconstruction.
Synergistic effects associated with climate change and the development of rocky shore molluscs
Przeslawski, R Davis, AR Benkendorff, K
GLOBAL CHANGE BIOLOGY 11:3 515-522
Global climate change and ozone layer thinning will simultaneously expose organisms to increasingly stressful conditions. Early life stages of marine organisms, particularly eggs and larvae, are considered most vulnerable to environmental extremes. Here, we exposed encapsulated embryos of three common rocky shore gastropods to simultaneous combinations of ecologically realistic levels of ultraviolet radiation (UVR), water temperature stress and salinity stress to identify potential interactions and associated impacts of climate change. We detected synergistic effects with increases in mortality and retardation in development associated with the most physiologically stressful conditions. The effects of UVR were particularly marked, with mortality increasing up to 12-fold under stressful conditions. Importantly, the complex outcomes observed on applying multiple stressors could not have been predicted from examining environmental variables in isolation. Hence, we are probably dramatically underestimating the ecological impacts of climate change by failing to consider the complex interplay of combinations of environmental variables with organisms.
Effects of large-scale climatic fluctuations on survival and production of young in a Neotropical migrant songbird, the yellow warbler Dendroica petechia
Mazerolle, DF Dufour, KW Hobson, KA den Haan, HE
JOURNAL OF AVIAN BIOLOGY 36:2 155-163
Migrant songbirds are vulnerable to changes in climatic conditions on both the breeding and wintering grounds. For North American Neotropical migrants, the El Nino/Southern Oscillation (ENSO), via its effects on global precipitation and temperature, modulates the productivity of their temperate and tropical terrestrial ecosystems used during the course of their annual cycle. We evaluated how a densely nesting population of yellow warblers Dendroica petechia in a riparian forest in southern Manitoba, Canada, responded to the El Nino/Southern Oscillation (ENSO) between 1992 and 2001. Standardized mist netting was used to estimate apparent annual survival of adults and production of young. Both adult survival and the production of young were positively correlated with the Southern Oscillation Index (SOI). More specifically, values of both these demographic parameters were lowest during El Nino years and highest during La Nina years. These findings demonstrate the influence of climate on populations of Neotropical migrants in North America. The more frequent El Ninos predicted to result from future global climate change could negatively affect populations of yellow warblers and other Neotropical migrants breeding in this region.
Rainfall exclusion in an eastern amazonian forest alters soil water movement and depth of water uptake
Romero-Saltos, H Sternberg, LDSL Moreira, MZ Nepstad, DC
AMERICAN JOURNAL OF BOTANY 92:3 443-455
Deuterium-labeled water was used to study the effect of the Tapajos Throughfall Exclusion Experiment (TTEE) on soil moisture movement and on depth of water uptake by trees of Coussarea racemosa, Sclerolobium chrysophyllum, and Eschweilera pedicellata. The TTEE simulates an extended dry season in an eastern Amazonian rainforest, a plausible scenario if the El Nino phenomenon changes with climate change. The TTEE excludes 60% of the wet season throughfall from a 1-ha plot (treatment), while the control 1-ha plot receives precipitation year-round. Mean percolation rate of the label peak in the control plot was greater than in the treatment plot during the wet season (0.75 vs. 0.07 m/mo). The rate was similar for both plots during the dry season (ca. 0. 15 m/mo), indicative that both plots have similar topsoil structure. Interestingly, the label peak in the control plot during the dry season migrated upward an average distance of 64 cm. We show that water probably moved upward through soil pores-i.e., it did not involve roots (hydraulic lift)-most likely because of a favorable gradient of total (matric + gravitational) potential coupled with sufficient unsaturated hydraulic conductivity. Water probably also moved upward in the treatment plot, but was not detectable; the label in this plot did not percolate below 1 m or beyond the depth of plant water uptake. During the dry season, trees in the rainfall exclusion plot, regardless of species, consistently absorbed water significantly deeper, but never below 1.5-2 m, than trees in the control plot, and therefore may represent expected root function of this understory/subcanopy tree community during extended dry periods.
One- and three-hour PM2.5 characterization, speciation, and source apportionment using continuous and integrated samplers
Long, RW Modey, WK Smith, PS Smith, R Merrill, C Pratt, J Stubbs, A Eatough, NL Eatough, DJ Malm, WC Wilson, WE
AEROSOL SCIENCE AND TECHNOLOGY 39:3 238-248
Ammonium nitrate and semivolatile organic compounds (SVOC) are significant components of fine particles in many urban atmospheres. These components, however, are not properly measured by current EPA accepted methods, such as the R&P TEOM monitor, due to loss of semivolatile material (SVM) from particles in the heated environment of the filter during sampling. The accurate determination of semivolatile material is important due to the possible effects of these species on human health, visibility, and global climate change. The concentration and composition of fine particulate material were determined using a combination of continuous and integrated samplers at the Brigham Young University-EPA Environmental Monitoring for Public Access and Community Tracking (BYU-EPA EMPACT) monitoring site in Salt Lake City, Utah over a six-day sampling period (30 January to 4 February) during the winter of 2001. Continuous samples were collected using a RAMS (total PM2.5 mass), a TEOM monitor (nonvolatile PM2.5 mass), an Aethalometer (elemental carbon), a TSI CPC (particle count), and a Nephelometer (light scattering by particles, bsp). Fine particle composition and mass were determined on a three-hour basis using the PC-BOSS diffusion denuder sampler. Total PM2.5 mass-determined with the RAMS agreed with constructed mass determined from the chemical composition measured in collocated PC-BOSS-integrated samples. Results from this study indicate that semivolatile material (ammonium nitrate and semivolatile organic compounds) is a significant component of fine particle mass. Semivolatile organic compounds were the major contributor to light scattering during the six-day sampling period. Semivolatile nitrate, but not organic material, was suggested to be hygroscopic by the nephelometric data. The majority of the SVM observed appeared to be secondary material formed from photochemical reactions of the organic and NOx emissions from mobile sources and wood smoke combustion.
Global warming and the mining of oceanic methane hydrate
Lai, CCA Dietrich, DE Bowman, MJ
TOPICS IN CATALYSIS 32:3-4 95-99
The impacts of global warming oil the environment. economy and society are presently receiving much attention by the international community. However, the extent to which anthropogenic factors are the main cause of global warming, is still being, debated. There are obviously large stakes associated with the validity of any theory since that will indicate what actions need to be taken to protect the human race’s only home-Earth. Most studies of global warming have investigated the rates and quantities of carbon dioxide emitted into the atmosphere since the beginning of the industrial revolution. In this paper, We focus on the earth’s carbon budget and the associated energy transfer between various components of the climate system. This research invokes some new concepts: (i) certain biochemical processes which strongly interact with geophysical processes in climate system: (ii) a hypothesis that internal processes in the oceans rather than in the atmosphere are Lit the center of global warming; (iii) chemical energy stored in biochemical processes call significantly affect ocean dynamics and therefore the climate system. Based oil those concepts. we propose a new hypothesis for global warming. We also propose I revolutionary strategy to deal with global climate change and provide domestic energy security at the same time. Recent ocean exploration indicates that huge deposits of oceanic methane hydrate deposits exist on the seafloor on continental margins. Methane hydrate transforms into water and methane gas when it dissociates. So, this potentially could provide the United States with energy security if the technology for mining in the 200-mile EEZ is developed and is economically viable. Further, methane hydrate is a relatively environmentally, benign, clean fuel. Such technology would help industry reduce carbon dioxide emissions to the atmosphere, I rid thus reduce global warming by harnessing, the energy from the deep sea.
Relay cropping for improved air and water quality
Schepers, JS Francis, DD Shanahan, JF
ZEITSCHRIFT FUR NATURFORSCHUNG C-A JOURNAL OF BIOSCIENCES 60:3-4 186-189
Using plants to extract excess nitrate from soil is important in protecting against eutrophication of standing water, hypoxic conditions in lakes and oceans, or elevated nitrate concentrations in domestic water supplies. Global climate change issues have raised new concerns about nitrogen (N) management as it relates to crop production even though there may not be an immediate threat to water quality. Carbon dioxide (CO2) emissions are frequently considered the primary cause of global climate change, but under anaerobic conditions, animals can contribute by expelling methane (CH4) as do soil microbes. In terms of the potential for global climate change, CH4 is similar to 25 times more harmful than CO2. This differential effect is minuscule compared to when nitrous oxide (N2O) is released into the atmosphere because it is similar to 300 times more harmful than CO2. N2O losses from soil have been positively correlated with residual N (nitrate, NO3) concentrations in soil. It stands to reason that phytoremediation via nitrate scavenger crops is one approach to help protect air quality, as well as soil and water quality. Winter wheat was inserted into a seed corn/soybean rotation to utilize soil nitrate and thereby reduce the potential for nitrate leaching and N2O emissions. The net effect of the 2001-2003 relay cropping sequence was to produce three crops in two years, scavenge 130 kg N/ha from the root zone, produce an extra 2 Mg residue/ha, and increase producer profitability by similar to$ 250/ha.
Climate change impacts for the conterminous USA: An integrated assessment - Part 4: Water resources
Thomson, AM Brown, RA Rosenberg, NJ Srinivasan, R Izaurralde, RC
CLIMATIC CHANGE 69:1 67-88
Global climate change will impact the hydrologic cycle by increasing the capacity of the atmosphere to hold moisture. Anticipated impacts are generally increased evaporation at low latitudes and increased precipitation at middle and high latitudes. General Circulation Models (GCMs) used to simulate climate disagree on whether the U.S. as a whole and its constituent regions will receive more or less precipitation as global warming occurs. The impacts on specific regions will depend on changes in weather patterns and are certain to be complex. Here we apply the suite of 12 potential climate change scenarios, previously described in Part 1, to the Hydrologic Unit Model of the United States (HUMUS) to simulate water supply in the conterminous United States in reference to a baseline scenario. We examine the sufficiency of this water supply to meet changing demands of irrigated agriculture. The changes in water supply driven by changes in climate will likely be most consequential in the semi-arid western parts of the country where water yield is currently scarce and the resource is intensively managed. Changes of greater than +/-50% with respect to present day water yield are projected in parts of the Midwest and Southwest U.S. Interannual variability in the water supply is likely to increase where conditions become drier and to decrease under wetter conditions.
Summary of a workshop on the development of health models and scenarios: Strategies for the future
Ebi, KL Gamble, JL
ENVIRONMENTAL HEALTH PERSPECTIVES 113:3 335-338
A workshop was convened in July 2003 by the Global Change Research Program, Office of Research and Development at the U.S. Environmental Protection Agency, to review current strategies for developing human health models and scenarios in the context of global environmental change, particularly global climate change, and to outline a research agenda that effectively characterizes the interplay of global change with the health of human populations. The research agenda developed at the workshop focused on three issues: a) the development of health models, b) the development of health scenarios, and c) the use of health models and health scenarios to inform policy. The agenda identified research gaps as well as barriers to the development and use of models and scenarios. This report summarizes the workshop findings.
Soil carbon and the mitigation of global climate change
QUIMICA NOVA 28:2 329-334
SOIL CARBON AND THE MITIGATION OF GLOBAL CLIMATE CHANGE. The soils of the world contain more carbon than the combined total amounts occurring in vegetation and the atmosphere. Hence soils are a major reservoir of carbon in terrestrial ecosystems and an important sink. Recently, emphasis has been placed on the need to sequester carbon from atmospheric carbon dioxide into soil organic matter because of international concerns about greenhouse gas emissions and global climate change. The best strategies to built-up carbon stocks in the soil are basically those that increase the input of organic matter to the soil, and/or decrease the rate of soil organic matter decomposition. Grain crop systems based on soil ploughing and harrowing lead to Co-2 emissions combined with tremendous soil losses. In Brazil, no-tillage system was introduced to combat soil erosion by water and this soil management led to the build-up of soil carbon stocks with simultaneous high crop yields. However, the present procedure used to quantify carbon stocks in soils is laborious and of high cost. The use of infrared spectroscopy is very promising as an alternative low-cost method of soil carbon determination.
The Brazilian air transportation sector in the context of global climate change: CO2 emissions and mitigation alternatives
Simoes, AF Schaeffer, R
ENERGY CONVERSION AND MANAGEMENT 46:4 501-513
The purpose of this study is to discuss the participation of Brazilian air transportation within the context of global climate change. It first briefly presents an inventory of CO:! emissions caused by airborne activities in Brazil and then shows a trend projection through to 2023, indicating the progress of these emissions, with eight possible mitigation strategies. The abatement potential for each of these strategies is also investigated. It is estimated that joint implementation of all these strategies within a typical projection of broad based sustainability (based on renewable energy sources with fair social., economic and technological development) could result in an annual reduction in CO2 emissions caused by airborne activities in Brazil up to 28.5% (compared to the trend projection for 2023). It is also estimated that the emissions avoided through joint implementation of the mitigation alternatives analyzed may well reach 82,000 Gg (or 10(9) g) of CO2 from 2003 through 2023. (C) 2004 Elsevier Ltd. All rights reserved.
Effect of temperature, elevated carbon dioxide, and drought during seed development on the isoflavone content of dwarf soybean [Glycine max (L.) Merrill] grown in controlled environments
Caldwell, CR Britz, SJ Mirecki, RM
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 53:4 1125-1129
The effects of elevated temperature, carbon dioxide, and water stress on the isoflavone content of seed from a dwarf soybean line [Glycine max (L.) Merrill] were determined, using controlled environment chambers. Increasing the temperature from 18 degreesC during seed development to 23 degreesC decreased total isoflavone content by about 65%. A further 5 degreesC increase to 28 degreesC decreased the total isoflavone content by about 90%. Combining treatments at elevated temperature with elevated CO2 (700 ppm) and water stress to determine the possible consequences of global climate change on soybean seed isoflavone content indicated that elevated CO2 at elevated temperatures could partially reverse the effects of temperature on soybean seed isoflavone content. The addition of drought stress to plants grown at 23 degreesC and elevated CO2 returned the total isoflavone levels to the control values obtained at 18 degreesC and 400 ppm CO2. The promotive effects of drought and elevated CO2 at 23 degreesC on the 6”-O-malonygenistin and genistin levels were additive. The individual isoflavones often had different responses to the various growth conditions during seed maturation, modifying the proportions of the principal isoflavones. Therefore, subtle changes in certain environmental factors may change the isoflavone content of commercially grown soybean, altering the nutritional values of soy products.
Arctic sea ice trends and narwhal vulnerability
Laidre, KL Heide-Jorgensen, MP
BIOLOGICAL CONSERVATION 121:4 509-517
Conservation measures related to global climate change require that species vulnerability be incorporated into population risk models, especially for those that are highly susceptible to rapid or extreme changes due to specialized adaptation. In the case of Arctic cetaceans, effects of climate change on habitat and prey availability have been subject to intense speculation. Climate perturbations may have significant impacts on the fitness and success of this group, yet measuring these parameters for conservation purposes is complicated by remote and offshore preferences. The narwhal (Monodon monoceros) in Baffin Bay occupies a habitat where reversed (increasing) regional sea ice trends have been detected over 50 years. We used a combination of long-term narwhal satellite tracking data and remotely sensed sea ice concentrations to detect localized habitat trends and examine potential vulnerability. Spatial and temporal variability in the fraction of open water were examined on two narwhal wintering grounds between November and April, 1978-2001 using approximate sea ice concentrations derived from microwave SSMR/SSMI passive brightness temperatures. Less than 3% open water was available to narwhals between 15 January and 15 April, and reached minima of 0.5% open water at the end of March (125 km(2) out of a 25,000 km(2) area). Decreasing trends in the fraction of open water, together with increasing trends in interannual variability, were detected on both wintering grounds, significantly in northern Baffin Bay (-0.04% per year, SE 0.02). The limited number of leads and cracks available to narwhals during the winter, in combination with localized decreasing trends in open water and high site fidelity, suggests vulnerability to changes in Arctic sea ice conditions. Increasing risk of ice entrapments, many of which may go undetected in remote offshore areas, should be incorporated into population risk assessments as this may exceed the natural response capacity of the species. (C) 2004 Elsevier Ltd. All rights reserved.
Terrestrial C sequestration at elevated-CO2 and temperature: The role of dissolved organic N loss
Rastetter, EB Perakis, SS Shaver, GR Agren, GI
ECOLOGICAL APPLICATIONS 15:1 71-86
We used a simple model of carbon-nitrogen (C-N) interactions in terrestrial ecosystems to examine the responses to elevated CO2 and to elevated CO2 Plus warming in ecosystems that had the same total nitrogen loss but that differed in the ratio of dissolved organic nitrogen (DON) to dissolved inorganic nitrogen (DIN) loss. We postulate that DIN losses can be curtailed by higher N demand in response to elevated CO2, but that DON losses cannot. We also examined simulations in which DON losses were held constant, were proportional to the amount of soil organic matter, were proportional to the soil C:N ratio, or were proportional to the rate of decomposition. We found that the mode of N loss made little difference to the short-term (<60 years) rate of carbon sequestration by the ecosystem, but high DON losses resulted in much lower carbon sequestration in the long term than did low DON losses. In the short term, C sequestration was fueled by an internal redistribution of N froth soils to vegetation and by increases in the C:N ratio of soils and vegetation. This sequestration was about three times larger with elevated CO2 and warming than with elevated CO2 alone. After year 60, C sequestration was fueled by a net accumulation of N in the ecosystem, and the rate of sequestration was about the same with elevated CO, and warming as with elevated CO2 alone. With high DON losses, the ecosystem either sequestered C slowly after year 60 (when DON losses were constant or proportional to soil organic matter) or lost C (when DON losses were proportional to the soil C:N ratio or to decomposition). We conclude that changes in long-term C sequestration depend not only on the magnitude of N losses, but also on the form of those losses.
Responses of a beaded Arctic stream to short-term N and P fertilisation
Benstead, JP Deegan, LA Peterson, BJ Huryn, AD Bowden, WB Suberkropp, K Buzby, KM Green, AC Vacca, JA
FRESHWATER BIOLOGY 50:2 277-290
1. Oligotrophic Arctic streams are likely to be sensitive to changes in hydrology and nutrient inputs predicted to occur as a consequence of future climate and land use change. To investigate the potential consequences of nutrient enrichment for low-order Arctic streams, we added ammonium-N and phosphorous to a second-order beaded, tundra stream on Alaska’s north slope. We measured responses in nutrient chemistry, chlorophyll a standing crop, and in the breakdown and macroinvertebrate colonisation of leaf litter over a 38-day summer period. 2. During the addition, nutrient concentrations immediately downstream of the dripper averaged 6.4 mum ammonium-N and 0.45 muM soluble reactive P. Concentrations upstream of the dripper averaged 0.54 muM ammonium-N and 0.03 muM soluble reactive P. Uptake of both nutrients was rapid. Concentrations were reduced on average to 28 % (ammonium-N) and 15 % (inorganic P) of maximum values within 1500 m. Standing crops of chlorophyll a on standardised samplers were significantly higher by the end of the experiment. Breakdown rates of senescent willow (Salix sp.) and sedge (Carex sp.) litter and associated fungal biomass were also significantly increased by nutrient addition. 3. Fertilisation resulted in four- to sevenfold higher macroinvertebrate abundance and two-to fourfold higher macroinvertebrate biomass in litter bags, as well as an increase in late-summer body mass of larval Nemoura stoneflies. 4. Our results are consistent with those of similar studies of larger streams in the high-Arctic region. Based on our short-term experiment, increased inputs of nutrients into these ecosystems, whether caused by climate change or more local disturbance, are likely to have profound ecological consequences. Longer-term effects of enrichment, and their interaction with other components of future change in climate or land use, are more difficult to assess.
Brazilian energy policies side-effects on CO2 emissions reduction
Szklo, AS Schaeffer, R Schuller, ME Chandler, W
ENERGY POLICY 33:3 349-364
This study focuses on some of the programs and measures Brazil has undertaken over the past two or three decades in order to mitigate economic or environmental problems, which have also had positive effects on the reduction of the country’s carbon dioxide emissions. Results show that, in the year 2000 alone, some 11% in CO2 emissions from energy use in Brazil have been reduced compared to what would have been emitted that year had the actions reviewed here not been implemented in good time. As these actions have not been motivated as a strategy to curb global climate change, if their benefits related to avoided carbon emissions are not fully appraised in the near future, chances are that these policies may be discontinued. For instance, in the case of the business-as-usual scenario drawn up by the Ministry of Mines and Energy in 2001, the discontinuity of the policies analyzed here would result in CO2 emissions 20% higher by 2020, compared to what would happen were these policies kept over the long term. Therefore, the perspective presented here spotlights some of the hidden benefits of the programs and measures underway in the country, justifying their continuation or even intensification. (C) 2003 Elsevier Ltd. All rights reserved.
Aerosol properties and their spatial and temporal variations over North China in spring 2001
Xia, XA Chen, HB Wang, PC Zong, XM Qiu, JH Gouloub, P
TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY 57:1 28-39
Aerosol properties and their spatial and temporal variations over North China were analysed based on ground- based radiometer data for spring 2001. On the basis of the retrievals from sun/ sky radiance and broad- band radiation measurements at four AERONET stations and eight first- class radiation stations over North China, the analysis comprised a detailed description of aerosol loading, size and absorption in this period. The impact of dust events on aerosol properties over the downwind region was emphasized. Heavy aerosol loading and notable temporal variation over North China were revealed by both datasets. The average aerosol optical depth at 750 nm at the eight radiation stations ranged from 0.32 in Ejinaqi to 0.68 in Beijing, with the averaged coefficient of variation being 70%. Aerosol optical depth was dominantly contributed to by dust over western China, with 68% ( +/- 5%) of aerosol optical depth at 550 nm being attributed to large dust aerosols. A dramatic increase in aerosol optical depth associated with the remarkable decrease in the Angstrom wavelength exponent was observed in Beijing and Xianghe during the dust episode. This indicated that a huge number of large particles were emitted into the atmosphere during the dust period, with the result that the contribution to aerosol optical depth from coarse particles approached the value observed in the dust source region. Anthropogenic pollution also frequently contributed to the high aerosol optical depth in Beijing and Xianghe, but this was characterized by fine particles, with more than 70% of aerosol optical depth at 550 nm being attributed to fine particles. Pure desert aerosol in Chinese dust source regions absorbs much less solar radiation than predicted by known aerosol models. The retrieved single- scattering albedo was around 0.98 ( +/- 0.01) and had little wavelength dependence, which is in agreement with the ground- based and satellite retrievals in other dust source regions. Contrarily, anthropogenic aerosol exhibits much stronger absorption in the urban region, with the single- scattering albedo ranging from 0.89 +/- 0.04 (at 440 nm) to 0.83 +/- 0.05 (at 1020 nm). Due to the large difference in the absorption between dust and anthropogenic aerosol, the consequence of the input of a large volume of dust aerosols is not only to enhance the aerosol loading but also to reduce the aerosol absorption. Retrievals in Beijing showed that the single- scattering albedo increased to about 0.90 and had little spectral dependence when anthropogenic pollution and a dust event together affected Beijing; as for the pure dust period, it ranged from 0.92 at 440 nm to 0.97 at 1020 nm. The significant decrease in the aerosol absorption due to the dust outbreak can result in a decrease in aerosol atmospheric heating efficiency; this warrants further research since the increasing trend of aerosol loading with strong absorption in China is supposed to play an active role in regional and global climate change and the hydrological cycle.
Effects of carbon markets on the optimal management of slash pine (Pinus elliottii) plantations
Stainback, GA Alavalapati, JRR
SOUTHERN JOURNAL OF APPLIED FORESTRY 29:1 27-32
Global climate change is a growing concern among many policy makers. This concern has led to substantial interest in using forests as one option to mitigate climate change. In this article, the effect of internalizing carbon sequestration benefits on the optimal management of slash pine plantations is explored. Results suggest that without carbon bene is, it is optimal to use herbicide and bedding but not fertilizer because the increase in timber yield does notjustib7 the high cost offertilizer. With carbon benefits, however, the use of fertilizer becomes profitable. Thus a carbon market would likely induce plantation owners to increase their management intensity, which may in turn also have significant impacts on the amount of carbon sequestered. For example, by allowing the management regime to vary in addition to rotation age, the amount of carbon sequestered decreased from 204 to 164 metric tons of carbon per acre when carbon prices increased from $40 to $200 per metric ton. Thus increasing carbon sequestration on the intensive margin may be less feasible than previously supposed, but increasing on the extensive margin may be highly practicable.
Interactive effects of carbon dioxide, temperature, and ultraviolet-B radiation on soybean (Glycine max L.) flower and pollen morphology, pollen production, germination, and tube lengths
Koti, S Reddy, KR Reddy, VR Kakani, VG Zhao, DL
JOURNAL OF EXPERIMENTAL BOTANY 56:412 725-736
Plant reproduction is highly vulnerable to global climate change components such as carbon dioxide concentration ([CO2]), temperature (T), and ultraviolet-B (UV-B) radiation. The objectives of this study were to determine the effects of season-long exposure to treatments of [CO2] at 360 (control) and 720 mumol mol(-1) (+CO2), temperature at 30/22degreesC (control) and 38/30degreesC (+T) and UV-B radiation 0 (control) and 10 W m(-2) d(-1) (+UV-B) on flower and pollen morphology, pollen production, germination, and tube lengths of six soybean genotypes (D 88-5320, D 90-9216, Stalwart III, PI 471938, DG 5630RR, and DP 4933RR) in sunlit, controlled environment chambers. The control treatment had 360 mumol mol(-1) [CO2] at 30/22degreesC and 0 W UV-B. Plants grown either at +UV-B or +T, alone or in combination, produced smaller flowers with shorter standard petal and staminal column lengths. Flowers so produced had less pollen with poor pollen germination and shorter tube lengths. Pollen produced by the flowers of these plants appeared shrivelled without apertures and with disturbed exine ornamentation even at +CO2 conditions. The damaging effects of +T and +UV-B were not ameliorated by +CO2 conditions. Based on the total stress response index (TSRI), pooled individual component responses over all the treatments, the genotypes were classified as tolerant (DG 5630RR, D 88-5320: TSRI >-790), intermediate (D 90-9216, PI 471938: TSRI <-790 to >-1026), and sensitive (Stalwart III, DP 4933RR: TSRI <-1026). The differences in sensitivity identified among genotypes imply the options for selecting genotypes with tolerance to environmental stresses projected to occur in the future climates.
Effects of water stress and high nocturnal temperature on photosynthesis and nitrogen level of a perennial grass Leymus chinensis
Xu, ZZ Zhou, GS
PLANT AND SOIL 269:1-2 131-139
Water deficit and high temperature are important environmental factors restricting plant growth and photosynthesis. The two stresses often occur simultaneously, but their interactions on photosynthesis and nitrogen level have been less studied. In the present experiment, we measured photosynthetic parameters, stomatal density, and nitrogen levels, as well as soluble sugar content of leaves of a perennial grass, Leymus chinensis, experiencing two day/night temperature regimes of 30/20 degrees C and 30/25 degrees C, and five different soil moisture contents (the soil relative-water content ranged from 80% to 25 %). Leaf relative water content, leaf biomass, whole plant biomass, the ratio between the leaf biomass and total plant biomass, and the photosynthetic rate, as well as water-use efficiency decreased at high night temperature, especially under severe water stress conditions. Stomatal index was also increased by soil water stress except very severe water stress, and high nocturnal temperature decreased the leaf stomatal index under soil water stress. Nocturnal warming decreased nitrogen concentration in the leaves and increased it in the roots, particularly when plants were subjected to severe water stress. There were significant positive correlations between the photosynthetic rate and both soluble sugar concentration and nitrogen concentration at low nocturnal temperature. It is suggested that nocturnal warming significantly exacerbates the adverse effects of soil water stress, and their synergistic interactions might reduce the plant productivity and constrain its distribution in the region dominated by L. chinensis, based on predictions of global climate change.
Australia-wide predictions of soil properties using, decision trees
Henderson, BL Bui, EN Moran, CJ Simon, DAP
GEODERMA 124:3-4 383-398
This paper describes the construction of Australia-wide soil property predictions from a compiled national soils point database. Those properties considered include pH, organic carbon, total phosphorus, total nitrogen, thickness. texture, and clay content. Many of these soil properties are used directly in environmental process modelling including global climate change models. Models are constructed at the 250-m resolution using decision trees. These relate the soil property to the environment through a suite of environmental predictors at the locations where measurements are observed. These models are then used to extend predictions to the continental extent by applying the rules derived to the exhaustively available environmental predictors. The methodology and performance is described in detail for pH and summarized for other properties. Environmental variables are found to be important predictors, even at the 250-m resolution at which they are available here as they can describe the broad changes in soil property. (C) 2004 Elsevier B.V. All rights reserved.
Morphogenesis of the branching reef coral Madracis mirabilis
Kaandorp, JA Sloot, PMA Merks, RMH Bak, RPM Vermeij, MJA Maier, C
PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES 272:1559 127-133
Understanding external deciding factors in growth and morphology of reef corals is essential to elucidate the role of corals in marine ecosystems, and to explain their susceptibility to pollution and global climate change. Here, we extend on a previously presented model for simulating the growth and form of a branching coral and we compare the simulated morphologies to three-dimensional (313) images of the coral species Madracis mirabilis. Simulation experiments and isotope analyses of M. mirabilis skeletons indicate that external gradients of dissolved inorganic carbon (DIC) determine the morphogenesis of branching, phototrophic corals. In the simulations we use a first principle model of accretive growth based on local interactions between the polyps. The only species-specific information in the model is the average size of a polyp. From flow tank and simulation studies it is known that a relatively large stagnant and diffusion dominated region develops within a branching colony. We have used this information by assuming in our model that growth is entirely driven by a difftision-limited process, where DIC supply represents the limiting factor. With such model constraints it is possible to generate morphologies that are virtually indistinguishable from the 3D images of the actual colonies.
Global biomass mapping for an improved understanding of the CO2 balance - the Earth observation mission Carbon-3D
Hese, S Lucht, W Schmullius, C Barnsley, M Dubayah, R Knorr, D Neumann, K Riedel, T Schroter, K
REMOTE SENSING OF ENVIRONMENT 94:1 94-104
Understanding global climate change and developing strategies for sustainable use of our environmental resources are major scientific and political challenges. In response to an announcement of the German Aerospace Center (DLR) for a national Earth observation (EO) mission, the Friedrich-Schiller University Jena and the JenaOptronik GmbH proposed the EO mission Carbon-3D. The data products of this mission will for the first time accurately estimate aboveground biomass globally, one of the most important parameters of the carbon cycle. Simultaneous acquisition of multiangle optical with Light Detection and Ranging (LIDAR) observations is unprecedented. The optical imager extrapolates the laser-retrieved height profiles to biophysical vegetation maps. This innovative mission will reduce uncertainties about net effects of deforestation and forest regrowth on atmospheric CO2 concentrations and will also provide key biophysical information for biosphere models. (C) 2004 Elsevier Inc. All rights reserved.
Climate change impacts and vegetation response on the island of Madagascar
Ingram, JC Dawson, TP
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY OF LONDON SERIES A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES 363:1826 55-59
The island of Madagascar has been labelled the world’s number one conservation ‘hot spot’ because of increasing anthropogenic degradation of its natural habitats, which support a high level of species endemism. However, climatic phenomena may also have a significant impact upon the island’s flora and fauna. An analysis of 18 years of monthly satellite images from the National Oceanographic and Atmospheric Administration’s (NOAA) Advanced Very High Resolution Radiometer (AVHRR) have demonstrated that there is a dynamic pattern in Madagascar’s vegetative cover both annually and seasonally throughout 1982-1999. Over interannual time-scales, we show that this vegetation response, calculated using the normalized difference vegetation index (NDVI), has a strong negative correlation with the El Nino Southern Oscillation (ENSO), which can be attributable to drought events and associated wildfires. Global climate change is predicted to increase the frequency of the ENSO phenomenon, resulting in further decline of Madagascar’s natural environment.
Plausible impact of global climate change on water resources in the Tarim River Basin
Chen, YN Xu, ZX
SCIENCE IN CHINA SERIES D-EARTH SCIENCES 48:1 65-73
Combining the temperature and precipitation data from 77 climatological stations and the climatic and hydrological change data from three headstreams of the Tarim River: Hotan, Yarkant, and Aksu in the study area, the plausible association between climate change and the variability of water resources in the Tarim River Basin in recent years was investigated, the long-term trend of the hydrological time series including temperature, precipitation, and streamflow was detected, and the possible association between the El Nino/Southern Oscillation (ENSO) and these three kinds of time series was tested. The results obtained in this study show that during the past years, the temperature experienced a significant monotonic increase at the speed of 5%, nearly 1 degrees C rise; the precipitation showed a significant decrease in the 1970s, and a significant increase in the 1980s and 1990s, the average annual precipitation was increased with the magnitude of 6.8 mm per decade. A step change occurred in both temperature and precipitation time series around 1986, which may be influenced by the global climate change. Climate change resulted in the increase of the streamflow at the headwater of the Tarim River, but the anthropogenic activities such as over-depletion of the surface water resulted in the decrease of the streamflow at the lower reaches of the Tarim River. The study result also showed that there is no significant association between the ENSO and the temperature, precipitation and streamflow.
Four new species of Lobulia (Lacertilia : Scincidae) from high altitude in New Guinea
Greer, AE Allison, A Cogger, HG
HERPETOLOGICAL MONOGRAPHS :19 153-179
Four new species of scincid lizards in the genus Lobulia are described from high elevations (>= 2350 m) in New Guinea. Some of the features that may permit these skinks to live at high elevation are: dark color pattern, “tinted” lower eyelids and live-bearing reproductive mode. All of the species may be threatened by global climate warming. The generic concept of Lobulia is discussed and a key to the species provided.
Mapping environments at risk under different global climate change scenarios
Saxon, E Baker, B Hargrove, W Hoffman, F Zganjar, C
ECOLOGY LETTERS 8:1 53-60
All global circulation models based on Intergovernmental Panel on Climate Change (IPCC) scenarios project profound changes, but there is no consensus on how to map their environmental consequences. Our multivariate representation of environmental space combines stable topographic and edaphic attributes with dynamic climatic attributes. We divide that environmental space into 500 unique domains and map their current locations and their projected locations in 2100 under contrasting emissions scenarios. The environmental domains found across half the study area today disappear under the higher emissions scenario, but persist somewhere in it under the lower emissions scenario. Locations affected least and those affected most under each scenario are mapped. This provides an explicit framework for designing conservation networks to include both areas at least risk (potential refugia) and areas at greatest risk, where novel communities may form and where sentinel ecosystems can be monitored for signs of stress.
Selective adsorption of a substance derived from saccharides onto synthetic resin particles
Hattori, H Tajima, K Chang, HT Murayama, T Furuya, E
ADSORPTION-JOURNAL OF THE INTERNATIONAL ADSORPTION SOCIETY 11: Suppl. 1 917-920
Most, if not all, of the chemicals and chemical products are made using crude oils as the feedstock. However, this feedstock is decreasing and the utilization of it is causing global climate change. An alternative feedstock must be developed to alleviate these problems. Saccharides (sugars) meet these requirements partly because many useful intermediates and products can be obtained in the presence of an acid. In the case when D-fructose reacts with concentrate hydrochloric acid, 5-hydroxymethyl-furfural (HMF) is formed as the primary product. HMF is well known as one of many useful chemicals from biomass. However, it reacts further to form a HMF dimmer, and it also decomposes to smaller molecules such as levulinic acid. This kind of complex reaction is difficult to control through process variables including temperature, time, pressure, and solvent, in order to obtain selectively a specific product. In this study, a method of direct reaction control using adsorption in the same vessel. The results show that HMF dimmer can be selectively adsorbed onto synthetic resin particles. The results are almost the same as those obtained from a phenolics-carbonaceous adsorbent system.
Monitoring the oceanic flow between Africa and Antarctica: Report of the first GoodHope cruise
Ansorge, IJ Speich, S Lutjeharms, JRE Goni, GJ Rautenbach, CJD Froneman, PW Rouault, M Garzoli, S
SOUTH AFRICAN JOURNAL OF SCIENCE 101:1-2 29-35
THE SOUTHERN OCEAN PLAYS A MAJOR role in the global oceanic circulation, as a component of the Meridional Overturning Circulation, and it is postulated that it has a great influence on present-day climate. However, our understanding of its complex three-dimensional dynamics and of the impact of its variability on the climate system is rudimentary. The newly constituted, international GoodHope research venture aims to address this knowledge gap by establishing a programme of regular observations across the Southern Ocean between the African and Antarctic continents. The objectives of this programme are fivefold: (1) to improve understanding of Indo-Atlantic inter-ocean exchanges and their impact on the global thermohaline circulation and thus on global climate change; (2) to understand in more detail the influence these exchanges have on the climate variability of the southern African subcontinent; (3) to monitor the variability of the main Southern Ocean frontal systems associated with the Antarctic Circumpolar Current; (4) to study air-sea exchanges and their role on the global heat budget, with particular emphasis on the intense exchanges occurring within the Agulhas Retroflection region south of South Africa, and (5) to examine the role of major frontal systems as areas of elevated biological activity and as biogeographical barriers to the distribution of plankton. We present here preliminary results on the physical and biological structure of the frontal systems using the first GoodHope transect that was completed during February-March 2004.
Discrepancy of global climate change over continents and oceans
Byshev, VI Neiman, VG Romanov, YA
DOKLADY EARTH SCIENCES 400:1 77-83
Preserving biodiversity under current and future climates: a case study
Coulston, JW Riitters, KH
GLOBAL ECOLOGY AND BIOGEOGRAPHY 14:1 31-38
Aim The conservation of biological and genetic diversity is a major goal of reserve systems at local, regional, and national levels. The International Union for the Conservation of Nature and Natural Resources suggests a 12% threshold (area basis) for adequate protection of biological and genetic diversity of a plant community. However, thresholds based on area may protect only a small portion of the total diversity if the locations are chosen without regard to the variation within the community. The objectives of this study were to demonstrate methods to apply a coarse-filter approach for identifying gaps in the current reserve system of the Psuedotsuga menziesii (Douglas-fir) forest type group based on current climatic conditions and a global climate change scenario. Location Western United States. Method We used an ecological envelope approach that was based on seven bioclimatic factors, two topographic factors, and two edaphic factors. Multivariate factor analysis was then used to reduce the envelope to two dimensions. The relative density of habitat and protected areas were identified in each part of the envelope based on the current climate and potential future climate. We used this information to identify gaps in the reserve system. Results Although the protected areas occurred in all parts of the envelope, most existed in colder and drier areas. This was true for both the current climate and potential future climate. Main conclusion To protect more of the ecological envelope, future conservation efforts would be most effective in western Oregon, north-western Washington, and north-western California.
Global climate change and soil carbon stocks; predictions from two contrasting models for the turnover of organic carbon in soil
Jones, C McConnell, C Coleman, K Cox, P Falloon, P Jenkinson, D Powlson, D
GLOBAL CHANGE BIOLOGY 11:1 154-166
Enhanced release of CO2 to the atmosphere from soil organic carbon as a result of increased temperatures may lead to a positive feedback between climate change and the carbon cycle, resulting in much higher CO2 levels and accelerated global warming. However, the magnitude of this effect is uncertain and critically dependent on how the decomposition of soil organic C (heterotrophic respiration) responds to changes in climate. Previous studies with the Hadley Centre’s coupled climate-carbon cycle general circulation model (GCM) (HadCM3LC) used a simple, single-pool soil carbon model to simulate the response. Here we present results from numerical simulations that use the more sophisticated ‘RothC’ multipool soil carbon model, driven with the same climate data. The results show strong similarities in the behaviour of the two models, although RothC tends to simulate slightly smaller changes in global soil carbon stocks for the same forcing. RothC simulates global soil carbon stocks decreasing by 54 Gt C by 2100 in a climate change simulation compared with an 80 Gt C decrease in HadCM3LC. The multipool carbon dynamics of RothC cause it to exhibit a slower magnitude of transient response to both increased organic carbon inputs and changes in climate. We conclude that the projection of a positive feedback between climate and carbon cycle is robust, but the magnitude of the feedback is dependent on the structure of the soil carbon model.