WorldWideScience

Sample records for terrestrial ecosystem affected

  1. Terrestrial ecosystems and biodiversity

    CSIR Research Space (South Africa)

    Davis-Reddy, Claire

    2017-10-01

    Full Text Available Ecoregions Terrestrial Biomes Protected Areas Climate Risk and Vulnerability: A Handbook for Southern Africa | 75 7.2. Non-climatic drivers of ecosystem change 7.2.1. Land-use change, habitat loss and fragmentation Land-use change and landscape... concentrations of endemic plant and animal species, but these mainly occur in areas that are most threatened by human activity. Diverse terrestrial ecosystems in the region include tropical and sub-tropical forests, deserts, savannas, grasslands, mangroves...

  2. Radionuclides in terrestrial ecosystems

    International Nuclear Information System (INIS)

    Bocock, K.L.

    1981-01-01

    This report summarizes information on the distribution and movement of radionuclides in semi-natural terrestrial ecosystems in north-west England with particular emphasis on inputs to, and outputs from ecosystems; on plant and soil aspects; and on radionuclides in fallout and in discharges by the nuclear industry. (author)

  3. Radionuclides in terrestrial ecosystems

    International Nuclear Information System (INIS)

    Howard, B.J.; Kennedy, V.H.; Nelson, A.

    1983-06-01

    A bibliographical database has been developed to provide quick access to research and background literature in the field of radioecology. This is a development of an earlier database described by Nelson (Bocock 1981). ITE's particular fields of interest have led to a subject bias in the bibliography towards studies in Cumbria, especially those concerned with radionuclides originating from the reprocessing plant at Sellafield, and towards ecological research studies that are complementary to radionuclide studies. Other subjects covered, include the chemistry of radionuclides, budgets and transfers within ecosystems and techniques for the analysis of environmental samples. ITE's research objectives have led to the establishment of a specialized database which is intended to complement rather than compete with the large international databases made available by suppliers such as IRS-DIALTECH or DIALOG. Currently the database holds about 1900 references which are stored on a 2 1/2 megabyte hard disk on a Digital PDP11/34 computer operating under a time shared system. The references follow a standard format. (author)

  4. Parallel Computing for Terrestrial Ecosystem Carbon Modeling

    International Nuclear Information System (INIS)

    Wang, Dali; Post, Wilfred M.; Ricciuto, Daniel M.; Berry, Michael

    2011-01-01

    Terrestrial ecosystems are a primary component of research on global environmental change. Observational and modeling research on terrestrial ecosystems at the global scale, however, has lagged behind their counterparts for oceanic and atmospheric systems, largely because the unique challenges associated with the tremendous diversity and complexity of terrestrial ecosystems. There are 8 major types of terrestrial ecosystem: tropical rain forest, savannas, deserts, temperate grassland, deciduous forest, coniferous forest, tundra, and chaparral. The carbon cycle is an important mechanism in the coupling of terrestrial ecosystems with climate through biological fluxes of CO 2 . The influence of terrestrial ecosystems on atmospheric CO 2 can be modeled via several means at different timescales. Important processes include plant dynamics, change in land use, as well as ecosystem biogeography. Over the past several decades, many terrestrial ecosystem models (see the 'Model developments' section) have been developed to understand the interactions between terrestrial carbon storage and CO 2 concentration in the atmosphere, as well as the consequences of these interactions. Early TECMs generally adapted simple box-flow exchange models, in which photosynthetic CO 2 uptake and respiratory CO 2 release are simulated in an empirical manner with a small number of vegetation and soil carbon pools. Demands on kinds and amount of information required from global TECMs have grown. Recently, along with the rapid development of parallel computing, spatially explicit TECMs with detailed process based representations of carbon dynamics become attractive, because those models can readily incorporate a variety of additional ecosystem processes (such as dispersal, establishment, growth, mortality etc.) and environmental factors (such as landscape position, pest populations, disturbances, resource manipulations, etc.), and provide information to frame policy options for climate change

  5. Do high levels of diffuse and chronic metal pollution in sediments of Rhine and Meuse floodplains affect structure and functioning of terrestrial ecosystems?

    International Nuclear Information System (INIS)

    Rozema, Jelte; Notten, Martje J.M.; Aerts, Rien; Gestel, Cornelis A.M. van; Hobbelen, Peter H.F.; Hamers, Timo H.M.

    2008-01-01

    This paper (re)considers the question if chronic and diffuse heavy metal pollution (cadmium, copper, lead and zinc) affects the structure and functioning of terrestrial ecosystems of Biesbosch National Park, the floodplain area of rivers Meuse and Rhine. To reach this aim, we integrated the results of three projects on: 1. the origin, transfer and effects of heavy metals in a soil-plant-snail food chain; 2. the impact of bioavailability on effects of heavy metals on the structure and functioning of detritivorous communities; 3. the risk assessment of heavy metals for an herbivorous and a carnivorous small mammal food chain. Metal pollution levels of the Biesbosch floodplain soils are high. The bioavailability of metals in the soils is low, causing low metal levels in plant leaves. Despite this, metal concentrations in soil dwelling detritivores and in land snails at polluted locations are elevated in comparison to animals from 'non-polluted' reference sites. However, no adverse effects on ecosystem structure (species richness, density, biomass) and functioning (litter decomposition, leaf consumption, reproduction) have been found. Sediment metal pollution may pose a risk to the carnivorous small mammal food chain, in which earthworms with elevated metal concentrations are eaten by the common shrew. Additional measurements near an active metal smelter, however, show reduced leaf consumption rates and reduced reproduction by terrestrial snails, reflecting elevated metal bioavailability at this site. Since future management may also comprise reintroduction of tidal action in the Biesbosch area, changes in metal bioavailability, and as a consequence future ecosystem effects, cannot be excluded

  6. Terrestrial ecosystems in a changing world

    Energy Technology Data Exchange (ETDEWEB)

    Canadell, J.G. [CSIRO Marine and Atmospheric Research, Canberra, ACT (Australia). Global Carbon Project; Pataki, D.E. [California Univ., Irvine, CA (United States). Dept. of Earth System Science]|[California Univ., Irvine, CA (United States). Dept. of Ecology and Evolutionary Biology; Pitelka, L.F. (eds.) [Maryland Univ., Frostburg, MD (United States). Appalachian Lab.

    2007-07-01

    Over 100 authors present 25 contributions on the impacts of global change on terrestrial ecosystems including: * key processes of the earth system such as the CO2 fertilization effect, shifts in disturbances and biome distribution, the saturation of the terrestrial carbon sink, and changes in functional biodiversity, * ecosystem services such the production of wheat, pest control, and carbon storage in croplands, and * sensitive regions in the world threaten by rapid changes in climate and land use such as high latitudes ecosystems, tropical forest in Southeast Asia, and ecosystems dominated by Monsoon climate. The book also explores new research developments on spatial thresholds and nonlinearities, the key role of urban development in global biogeochemical processes, and the integration of natural and social sciences to address complex problems of the human-environment system. (orig.)

  7. Enchytraeids as indicator organisms for chemical stress in terrestrial ecosystems

    NARCIS (Netherlands)

    Didden, W.; Römbke, J.

    2001-01-01

    This review article surveys the available data on enchytraeid sensitivity toward chemical stress, and the effects of chemical stress on enchytraeid communities in terrestrial ecosystems. The factors affecting bioavailability of stressors to enchytraeids and the nature of direct and indirect effects

  8. Radionuclide transport processes in terrestrial ecosystems

    International Nuclear Information System (INIS)

    Whicker, F.W.

    1983-01-01

    Some major principles and the status of knowledge concerning the transport of radionuclides through terrestrial ecosystems are reviewed. Fundamental processes which control the flow of radionuclides between ecosystem components such as air, soil, plants, and animals are described, with emphasis on deposition, resuspension, plant uptake, ingestion, and assimilation. Properties of radionuclides, organisms, and ecosystems are examined in relation to their influence on the accumulation of radioactive materials by plants and animals. The effects of the physicochemical nature of the radionuclide; morphology, physiology, and behavior of the organism; and soil, nutrient, and trophic characteristics of the ecosystem are highlighted. Observations in natural ecosystems on radionuclides such as 137 Cs, 90 Sr, 131 I, 3 H, and 239 Pu are used to illustrate current concepts. An assessment of the degree to which the processes controlling radionuclide behavior are understood and of our ability to simulate and predict such behavior with computerized models is offered. Finally, brief comments are made on research needs

  9. Vulnerability of the global terrestrial ecosystems to climate change.

    Science.gov (United States)

    Li, Delong; Wu, Shuyao; Liu, Laibao; Zhang, Yatong; Li, Shuangcheng

    2018-05-27

    Climate change has far-reaching impacts on ecosystems. Recent attempts to quantify such impacts focus on measuring exposure to climate change but largely ignore ecosystem resistance and resilience, which may also affect the vulnerability outcomes. In this study, the relative vulnerability of global terrestrial ecosystems to short-term climate variability was assessed by simultaneously integrating exposure, sensitivity, and resilience at a high spatial resolution (0.05°). The results show that vulnerable areas are currently distributed primarily in plains. Responses to climate change vary among ecosystems and deserts and xeric shrublands are the most vulnerable biomes. Global vulnerability patterns are determined largely by exposure, while ecosystem sensitivity and resilience may exacerbate or alleviate external climate pressures at local scales; there is a highly significant negative correlation between exposure and sensitivity. Globally, 61.31% of the terrestrial vegetated area is capable of mitigating climate change impacts and those areas are concentrated in polar regions, boreal forests, tropical rainforests, and intact forests. Under current sensitivity and resilience conditions, vulnerable areas are projected to develop in high Northern Hemisphere latitudes in the future. The results suggest that integrating all three aspects of vulnerability (exposure, sensitivity, and resilience) may offer more comprehensive and spatially explicit adaptation strategies to reduce the impacts of climate change on terrestrial ecosystems. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  10. Divergent apparent temperature sensitivity of terrestrial ecosystem respiration

    Science.gov (United States)

    Bing Song; Shuli Niu; Ruise Luo; Yiqi Luo; Jiquan Chen; Guirui Yu; Janusz Olejnik; Georg Wohlfahrt; Gerard Kiely; Ako Noormets; Leonardo Montagnani; Alessandro Cescatti; Vincenzo Magliulo; Beverly Elizabeth Law; Magnus Lund; Andrej Varlagin; Antonio Raschi; Matthias Peichl; Mats B. Nilsson; Lutz Merbold

    2014-01-01

    Recent studies revealed convergent temperature sensitivity of ecosystem respiration (Re) within aquatic ecosystems and between terrestrial and aquatic ecosystems. We do not know yet whether various terrestrial ecosystems have consistent or divergent temperature sensitivity. Here, we synthesized 163 eddy covariance flux sites across the world and...

  11. Direct and terrestrial vegetation-mediated effects of environmental change on aquatic ecosystem processes

    Science.gov (United States)

    Becky A. Ball; John S. Kominoski; Heather E. Adams; Stuart E. Jones; Evan S. Kane; Terrance D. Loecke; Wendy M. Mahaney; Jason P. Martina; Chelse M. Prather; Todd M.P. Robinson; Christopher T. Solomon

    2010-01-01

    Global environmental changes have direct effects on aquatic ecosystems, as well as indirect effects through alterations of adjacent terrestrial ecosystem structure and functioning. For example, shifts in terrestrial vegetation communities resulting from global changes can affect the quantity and quality of water, organic matter, and nutrient inputs to aquatic...

  12. Resource subsidies between stream and terrestrial ecosystems under global change

    Science.gov (United States)

    Larsen, Stefano; Muehlbauer, Jeffrey D.; Marti Roca, Maria Eugenia

    2016-01-01

    Streams and adjacent terrestrial ecosystems are characterized by permeable boundaries that are crossed by resource subsidies. Although the importance of these subsidies for riverine ecosystems is increasingly recognized, little is known about how they may be influenced by global environmental change. Drawing from available evidence, in this review we propose a conceptual framework to evaluate the effects of global change on the quality and spatiotemporal dynamics of stream–terrestrial subsidies. We illustrate how changes to hydrological and temperature regimes, atmospheric CO2 concentration, land use and the distribution of nonindigenous species can influence subsidy fluxes by affecting the biology and ecology of donor and recipient systems and the physical characteristics of stream–riparian boundaries. Climate-driven changes in the physiology and phenology of organisms with complex life cycles will influence their development time, body size and emergence patterns, with consequences for adjacent terrestrial consumers. Also, novel species interactions can modify subsidy dynamics via complex bottom-up and top-down effects. Given the seasonality and pulsed nature of subsidies, alterations of the temporal and spatial synchrony of resource availability to consumers across ecosystems are likely to result in ecological mismatches that can scale up from individual responses, to communities, to ecosystems. Similarly, altered hydrology, temperature, CO2 concentration and land use will modify the recruitment and quality of riparian vegetation, the timing of leaf abscission and the establishment of invasive riparian species. Along with morphological changes to stream–terrestrial boundaries, these will alter the use and fluxes of allochthonous subsidies associated with stream ecosystems. Future research should aim to understand how subsidy dynamics will be affected by key drivers of global change, including agricultural intensification, increasing water use and biotic

  13. How lichens impact on terrestrial community and ecosystem properties.

    Science.gov (United States)

    Asplund, Johan; Wardle, David A

    2017-08-01

    Lichens occur in most terrestrial ecosystems; they are often present as minor contributors, but in some forests, drylands and tundras they can make up most of the ground layer biomass. As such, lichens dominate approximately 8% of the Earth's land surface. Despite their potential importance in driving ecosystem biogeochemistry, the influence of lichens on community processes and ecosystem functioning have attracted relatively little attention. Here, we review the role of lichens in terrestrial ecosystems and draw attention to the important, but often overlooked role of lichens as determinants of ecological processes. We start by assessing characteristics that vary among lichens and that may be important in determining their ecological role; these include their growth form, the types of photobionts that they contain, their key functional traits, their water-holding capacity, their colour, and the levels of secondary compounds in their thalli. We then assess how these differences among lichens influence their impacts on ecosystem and community processes. As such, we consider the consequences of these differences for determining the impacts of lichens on ecosystem nutrient inputs and fluxes, on the loss of mass and nutrients during lichen thallus decomposition, and on the role of lichenivorous invertebrates in moderating decomposition. We then consider how differences among lichens impact on their interactions with consumer organisms that utilize lichen thalli, and that range in size from microfauna (for which the primary role of lichens is habitat provision) to large mammals (for which lichens are primarily a food source). We then address how differences among lichens impact on plants, through for example increasing nutrient inputs and availability during primary succession, and serving as a filter for plant seedling establishment. Finally we identify areas in need of further work for better understanding the role of lichens in terrestrial ecosystems. These include

  14. Terrestrial invertebrates in the Rhynie chert ecosystem.

    Science.gov (United States)

    Dunlop, Jason A; Garwood, Russell J

    2018-02-05

    The Early Devonian Rhynie and Windyfield cherts remain a key locality for understanding early life and ecology on land. They host the oldest unequivocal nematode worm (Nematoda), which may also offer the earliest evidence for herbivory via plant parasitism. The trigonotarbids (Arachnida: Trigonotarbida) preserve the oldest book lungs and were probably predators that practiced liquid feeding. The oldest mites (Arachnida: Acariformes) are represented by taxa which include mycophages and predators on nematodes today. The earliest harvestman (Arachnida: Opiliones) includes the first preserved tracheae, and male and female genitalia. Myriapods are represented by a scutigeromorph centipede (Chilopoda: Scutigeromorpha), probably a cursorial predator on the substrate, and a putative millipede (Diplopoda). The oldest springtails (Hexapoda: Collembola) were probably mycophages, and another hexapod of uncertain affinities preserves a gut infill of phytodebris. The first true insects (Hexapoda: Insecta) are represented by a species known from chewing (non-carnivorous?) mandibles. Coprolites also provide insights into diet, and we challenge previous assumptions that several taxa were spore-feeders. Rhynie appears to preserve a largely intact community of terrestrial animals, although some expected groups are absent. The known fossils are (ecologically) consistent with at least part of the fauna found around modern Icelandic hot springs.This article is part of a discussion meeting issue 'The Rhynie cherts: our earliest terrestrial ecosystem revisited'. © 2017 The Author(s).

  15. Remote sensing the vulnerability of vegetation in natural terrestrial ecosystems

    Science.gov (United States)

    Alistair M. S. Smith; Crystal A. Kolden; Wade T. Tinkham; Alan F. Talhelm; John D. Marshall; Andrew T. Hudak; Luigi Boschetti; Michael J. Falkowski; Jonathan A. Greenberg; John W. Anderson; Andrew Kliskey; Lilian Alessa; Robert F. Keefe; James R. Gosz

    2014-01-01

    Climate change is altering the species composition, structure, and function of vegetation in natural terrestrial ecosystems. These changes can also impact the essential ecosystem goods and services derived from these ecosystems. Following disturbances, remote-sensing datasets have been used to monitor the disturbance and describe antecedent conditions as a means of...

  16. Using Ant Communities For Rapid Assessment Of Terrestrial Ecosystem Health

    Energy Technology Data Exchange (ETDEWEB)

    Wike, L

    2005-06-01

    relative health of the ecosystem. The IBI, though originally for Midwestern streams, has been successfully adapted to other ecoregions and taxa (macroinvertebrates, Lombard and Goldstein, 2004) and has become an important tool for scientists and regulatory agencies alike in determining health of stream ecosystems. The IBI is a specific type of a larger group of methods and procedures referred to as Rapid Bioassessment (RBA). These protocols have the advantage of directly measuring the organisms affected by system perturbations, thus providing an integrated evaluation of system health because the organisms themselves integrate all aspects of their environment and its condition. In addition to the IBI, the RBA concept has also been applied to seep wetlands (Paller et al. 2005) and terrestrial systems (O'Connell et al. 1998, Kremen et al. 1993, Rodriguez et al. 1998, Rosenberg et al. 1986). Terrestrial RBA methods have lagged somewhat behind those for aquatic systems because terrestrial systems are less distinctly defined and seem to have a less universal distribution of an all-inclusive taxon, such as fish in the IBI, upon which to base an RBA. In the last decade, primarily in Australia, extensive development of an RBA using ant communities has shown great promise. Ants have the same advantage for terrestrial RBAs that fish do for aquatic systems in that they are an essential and ubiquitous component of virtually all terrestrial ecosystems. They occupy a broad range of niches, functional groups, and trophic levels and they possess one very important characteristic that makes them ideal for RBA because, similar to the fishes, there is a wide range of tolerance to conditions within the larger taxa. Within ant communities there are certain groups, genera, or species that may be very robust and abundant under even the harshest impacts. There are also taxa that are very sensitive to disturbance and change and their presence or absence is also indicative of the local

  17. Herbivores Enforce Sharp Boundaries Between Terrestrial and Aquatic Ecosystems

    NARCIS (Netherlands)

    Sarneel, Judith M.; Huig, N.; Veen, G. F.; Rip, W.; Bakker, E. S.

    2014-01-01

    The transitions between ecosystems (ecotones) are often biodiversity hotspots, but we know little about the forces that shape them. Today, often sharp boundaries with low diversity are found between terrestrial and aquatic ecosystems. This has been attributed to environmental factors that hamper

  18. Microplastics as an emerging threat to terrestrial ecosystems.

    Science.gov (United States)

    de Souza Machado, Anderson Abel; Kloas, Werner; Zarfl, Christiane; Hempel, Stefan; Rillig, Matthias C

    2018-04-01

    Microplastics (plastics plastic litter or from direct environmental emission. Their potential impacts in terrestrial ecosystems remain largely unexplored despite numerous reported effects on marine organisms. Most plastics arriving in the oceans were produced, used, and often disposed on land. Hence, it is within terrestrial systems that microplastics might first interact with biota eliciting ecologically relevant impacts. This article introduces the pervasive microplastic contamination as a potential agent of global change in terrestrial systems, highlights the physical and chemical nature of the respective observed effects, and discusses the broad toxicity of nanoplastics derived from plastic breakdown. Making relevant links to the fate of microplastics in aquatic continental systems, we here present new insights into the mechanisms of impacts on terrestrial geochemistry, the biophysical environment, and ecotoxicology. Broad changes in continental environments are possible even in particle-rich habitats such as soils. Furthermore, there is a growing body of evidence indicating that microplastics interact with terrestrial organisms that mediate essential ecosystem services and functions, such as soil dwelling invertebrates, terrestrial fungi, and plant-pollinators. Therefore, research is needed to clarify the terrestrial fate and effects of microplastics. We suggest that due to the widespread presence, environmental persistence, and various interactions with continental biota, microplastic pollution might represent an emerging global change threat to terrestrial ecosystems. © 2017 John Wiley & Sons Ltd.

  19. Radionuclides in an arctic terrestrial ecosystem affected by atmospheric release from the Kraton-3 accidental underground nuclear explosion. 2001-2002

    International Nuclear Information System (INIS)

    Ramzaev, V.; Golikov, V.; Mishine, A.; Kaduka, M.; Burtcev, I.; Gedeonov, A.; Bulatenkov, Y.U.; Strand, P.; Brown, J.

    2004-01-01

    Current distributions of artificial radionuclides (ARN) were studied in the main compartments of a larch-tree forest lethally affected by a radioactive release from the Kraton-3 peaceful underground nuclear explosion (65.9 deg N, 112.3 deg E; Yakutia, Russia; 1978). Samples of soil, fungi, lichens, mosses, grasses, shrubs and trees were obtained at points belonging to four zones categorised by the severity of the ecosystem damage. Sampling was supplemented by dose rate measurements in air and mapping. The area of forest characterised by 100% lethality to adult larches (Larix gmelinii) and with partial, visually-detectable damage of other more radio-resistance species (e.g. lichens, mosses) covers a territory of approximately 1.2 km 2 . Elevated levels of long-lived ARN were found at all sampling sites. Maximum registered levels of the ground contamination with radionuclides of Cs, Sr and Pu were three orders of magnitude higher than those expected from global fallout. The ratios of 137 Cs to some other significant radionuclides in the ground contamination were as follows [mean (range)]: 90 Sr - 0.57(0.02-0.93); 239,240 Pu 44(25-72); 60 Co 470(220-760). Twenty-three years after a discrete contamination event, 90-95% of the total deposited radiocesium and plutonium has still remained in the lichen-moss on-ground cover and in the top 5 cm organic soil layer. At the same time, vertical and horizontal migrations of 90 Sr in soil were more pronounced. Strong surface contamination with 137 Cs, 90 Sr and plutonium was detected at the twigs and bark of the dead larches. The young larches that grew at the contaminated area following the initial destruction of the forest demonstrated a substantial ability to accumulate 137 Cs, 90 Sr and plutonium via roots, while the bushes selectively accumulated mainly radiostrontium. In contrast, some fungi concentrated mostly radiocesium. The levels of gamma dose rate in air and the environmental contamination with 137 Cs were found to

  20. Terrestrial ecosystems: an ecological content for radionuclide research

    International Nuclear Information System (INIS)

    Heal, O.W.; Horrill, A.D.

    1983-01-01

    The distribution and retention of radionuclides within terrestrial ecosystems varies greatly with both the radionuclide and the environmental conditions. Physico-chemical conditions, particularly those of the soil, strongly influence element retention but superimposed and interacting with these conditions are the biological processes which control the dynamics of the labile fraction of most elements. Net ecosystem production expresses the complementary biological processes of primary production and decomposition which control the internal element dynamics and the balance of inputs to and outputs from terrestrial ecosystems. Analysis of ecosystem structure and function has shown that although research often concentrates on relatively stable stages of ecosystem development, element retention is high during the early stages of ecosystem succession through the accumulation of plant biomass and dead organic matter. Element output tends to increase with time reaching a balance with inputs in mature ecosystems. Following disturbance, plant uptake tends to be reduced and decomposition stimulated, resulting in increased output until secondary succession and accumulation is re-established. Research on element dynamics in ecosystems indicates that major factors influencing the mobility of radionuclides in terrestrial systems will be the successional state of the ecosystem and intensity of disturbance. (author)

  1. Some effects of pollutants in terrestrial ecosystems

    Science.gov (United States)

    Stickel, W.H.; McIntyre, A.D.; Mills, C.F.

    1975-01-01

    occur when persistent chemicals enter organisms that eliminate them poorly. However, loss of chemicals in the food chain must be more common than accumulation. The great concentration from water to aquatic organism is chiefly a physical phenomenon, not a food chain effect, but it affords high starting levels for these chains. Terrestrial food chains often start at a high level with heavily contaminated, struggling prey. Litter feeders are another important base. Vegetation may be contaminated enough to be dangerous to animals that eat it. Dermal and respiratory routes of intoxication occur in the wild, but the oral route is far more important at most times and places. The organisms that govern soil fertility and texture are affected more by cultivation than by pesticides. Above ground, growing knowledge of resistance, species differences, and biological controls is leading to integrated control, in which use of chemicals is limited and specific. We do not know what is happening to most nontarget invertebrates. Amphibians and reptiles may be killed by applications of insecticides, but are not highly sensitive and can carry large residues. Effects of these residues on reproduction are little known. Heavy kills of birds by pesticides still occur in the field. Fish-eating and bird-eating birds also undergo shell thinning and related reproductive troubles in many areas, sometimes to the point of population decline and local or regional extermination. DDE most often correlates with shell thinning in the wild and in experiments. No other known chemical approaches DDE in causing severe and lasting shell thinning. Herbivorous birds seem to be largely immune to this effect. It is uncertain how much dieldrin and PCBs contribute to embryotoxicity in carnivorous birds. Mammals may be killed by the more toxic pesticides, but some of the commonest small rodents are so resistant, and lose their residues so rapidly, that they are of little

  2. Terrestrial ecosystem responses to global change: A research strategy

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-09-01

    Uncertainty about the magnitude of global change effects on terrestrial ecosystems and consequent feedbacks to the atmosphere impedes sound policy planning at regional, national, and global scales. A strategy to reduce these uncertainties must include a substantial increase in funding for large-scale ecosystem experiments and a careful prioritization of research efforts. Prioritization criteria should be based on the magnitude of potential changes in environmental properties of concern to society, including productivity; biodiversity; the storage and cycling of carbon, water, and nutrients; and sensitivity of specific ecosystems to environmental change. A research strategy is proposed that builds on existing knowledge of ecosystem responses to global change by (1) expanding the spatial and temporal scale of experimental ecosystem manipulations to include processes known to occur at large scales and over long time periods; (2) quantifying poorly understood linkages among processes through the use of experiments that manipulate multiple interacting environmental factors over a broader range of relevant conditions than did past experiments; and (3) prioritizing ecosystems for major experimental manipulations on the basis of potential positive and negative impacts on ecosystem properties and processes of intrinsic and/or utilitarian value to humans and on feedbacks of terrestrial ecosystems to the atmosphere.

  3. Endogenous circadian regulation of carbon dioxide exchange in terrestrial ecosystems

    Science.gov (United States)

    We tested the hypothesis that diurnal changes in terrestrial CO2 exchange are driven exclusively by the direct effect of the physical environment on plant physiology. We failed to corroborate this assumption, finding instead large diurnal fluctuations in whole ecosystem carbon assimilation across a ...

  4. Global simulation of interactions between groundwater and terrestrial ecosystems

    Science.gov (United States)

    Braakhekke, M. C.; Rebel, K.; Dekker, S. C.; Smith, B.; Van Beek, L. P.; Sutanudjaja, E.; van Kampenhout, L.; Wassen, M. J.

    2016-12-01

    In many places in the world ecosystems are influenced by the presence of a shallow groundwater table. In these regions upward water flux due to capillary rise increases soil moisture availability in the root zone, which has strong positive effect on evapotranspiration. Additionally it has important consequences for vegetation dynamics and fluxes of carbon and nitrogen. Under water limited conditions shallow groundwater stimulates vegetation productivity, and soil organic matter decomposition while under saturated conditions groundwater may have a negative effect on these processes due to lack of oxygen. Furthermore, since plant species differ with respect to their root distribution, preference for moisture conditions, and resistance to oxygen stress, shallow groundwater also influences vegetation type. Finally, processes such as denitrification and methane production occur under strictly anaerobic conditions and are thus strongly influenced by moisture availability. Most global hydrological models and several land surface models simulate groundwater table dynamics and their effects on land surface processes. However, these models typically have relatively simplistic representation of vegetation and do not consider changes in vegetation type and structure and are therefore less suitable to represent effects of groundwater on biogeochemical fluxes. Dynamic global vegetation models (DGVMs), describe land surface from an ecological perspective, combining detailed description of vegetation dynamics and structure and biogeochemical processes. These models are thus more appropriate to simulate the ecological and biogeochemical effects of groundwater interactions. However, currently virtually all DGVMs ignore these effects, assuming that water tables are too deep to affect soil moisture in the root zone. We have implemented a tight coupling between the dynamic global ecosystem model LPJ-GUESS and the global hydrological model PCR-GLOBWB. Using this coupled model we aim to

  5. Microplastics in the Terrestrial Ecosystem: Implications for Lumbricus terrestris (Oligochaeta, Lumbricidae).

    Science.gov (United States)

    Huerta Lwanga, Esperanza; Gertsen, Hennie; Gooren, Harm; Peters, Piet; Salánki, Tamás; van der Ploeg, Martine; Besseling, Ellen; Koelmans, Albert A; Geissen, Violette

    2016-03-01

    Plastic debris is widespread in the environment, but information on the effects of microplastics on terrestrial fauna is completely lacking. Here, we studied the survival and fitness of the earthworm Lumbricus terrestris (Oligochaeta, Lumbricidae) exposed to microplastics (Polyethylene, digestion of ingested organic matter, microplastic was concentrated in cast, especially at the lowest dose (i.e., 7% in litter) because that dose had the highest proportion of digestible organic matter. Whereas 50 percent of the microplastics had a size of earthworms. These concentration-transport and size-selection mechanisms may have important implications for fate and risk of microplastic in terrestrial ecosystems.

  6. Global variation of carbon use efficiency in terrestrial ecosystems

    Science.gov (United States)

    Tang, Xiaolu; Carvalhais, Nuno; Moura, Catarina; Reichstein, Markus

    2017-04-01

    Carbon use efficiency (CUE), defined as the ratio between net primary production (NPP) and gross primary production (GPP), is an emergent property of vegetation that describes its effectiveness in storing carbon (C) and is of significance for understanding C biosphere-atmosphere exchange dynamics. A constant CUE value of 0.5 has been widely used in terrestrial C-cycle models, such as the Carnegie-Ames-Stanford-Approach model, or the Marine Biological Laboratory/Soil Plant-Atmosphere Canopy Model, for regional or global modeling purposes. However, increasing evidence argues that CUE is not constant, but varies with ecosystem types, site fertility, climate, site management and forest age. Hence, the assumption of a constant CUE of 0.5 can produce great uncertainty in estimating global carbon dynamics between terrestrial ecosystems and the atmosphere. Here, in order to analyze the global variations in CUE and understand how CUE varies with environmental variables, a global database was constructed based on published data for crops, forests, grasslands, wetlands and tundra ecosystems. In addition to CUE data, were also collected: GPP and NPP; site variables (e.g. climate zone, site management and plant function type); climate variables (e.g. temperature and precipitation); additional carbon fluxes (e.g. soil respiration, autotrophic respiration and heterotrophic respiration); and carbon pools (e.g. stem, leaf and root biomass). Different climate metrics were derived to diagnose seasonal temperature (mean annual temperature, MAT, and maximum temperature, Tmax) and water availability proxies (mean annual precipitation, MAP, and Palmer Drought Severity Index), in order to improve the local representation of environmental variables. Additionally were also included vegetation phenology dynamics as observed by different vegetation indices from the MODIS satellite. The mean CUE of all terrestrial ecosystems was 0.45, 10% lower than the previous assumed constant CUE of 0

  7. Asynchronous exposure to global warming: freshwater resources and terrestrial ecosystems

    International Nuclear Information System (INIS)

    Gerten, Dieter; Lucht, Wolfgang; Ostberg, Sebastian; Heinke, Jens; Kundzewicz, Zbigniew W; Rastgooy, Johann; Schellnhuber, Hans Joachim; Kowarsch, Martin; Kreft, Holger; Warren, Rachel

    2013-01-01

    This modelling study demonstrates at what level of global mean temperature rise (ΔT g ) regions will be exposed to significant decreases of freshwater availability and changes to terrestrial ecosystems. Projections are based on a new, consistent set of 152 climate scenarios (eight ΔT g trajectories reaching 1.5–5 ° C above pre-industrial levels by 2100, each scaled with spatial patterns from 19 general circulation models). The results suggest that already at a ΔT g of 2 ° C and mainly in the subtropics, higher water scarcity would occur in >50% out of the 19 climate scenarios. Substantial biogeochemical and vegetation structural changes would also occur at 2 ° C, but mainly in subpolar and semiarid ecosystems. Other regions would be affected at higher ΔT g levels, with lower intensity or with lower confidence. In total, mean global warming levels of 2 ° C, 3.5 ° C and 5 ° C are simulated to expose an additional 8%, 11% and 13% of the world population to new or aggravated water scarcity, respectively, with >50% confidence (while ∼1.3 billion people already live in water-scarce regions). Concurrently, substantial habitat transformations would occur in biogeographic regions that contain 1% (in zones affected at 2 ° C), 10% (3.5 ° C) and 74% (5 ° C) of present endemism-weighted vascular plant species, respectively. The results suggest nonlinear growth of impacts along with ΔT g and highlight regional disparities in impact magnitudes and critical ΔT g levels. (letter)

  8. Terrestrial carbon cycle affected by non-uniform climate warming

    International Nuclear Information System (INIS)

    Jianyang Xia; Yiqi Luo; Jiquan Chen; Shilong Piao; Ciais, Philippe; Shiqiang Wan

    2014-01-01

    Feedbacks between the terrestrial carbon cycle and climate change could affect many ecosystem functions and services, such as food production, carbon sequestration and climate regulation. The rate of climate warming varies on diurnal and seasonal timescales. A synthesis of global air temperature data reveals a greater rate of warming in winter than in summer in northern mid and high latitudes, and the inverse pattern in some tropical regions. The data also reveal a decline in the diurnal temperature range over 51% of the global land area and an increase over only 13%, because night-time temperatures in most locations have risen faster than daytime temperatures. Analyses of satellite data, model simulations and in situ observations suggest that the impact of seasonal warming varies between regions. For example, spring warming has largely stimulated ecosystem productivity at latitudes between 30 degrees and 90 degrees N, but suppressed productivity in other regions. Contrasting impacts of day- and night-time warming on plant carbon gain and loss are apparent in many regions. We argue that ascertaining the effects of non-uniform climate warming on terrestrial ecosystems is a key challenge in carbon cycle research. (authors)

  9. The carbon balance of terrestrial ecosystems of China

    Directory of Open Access Journals (Sweden)

    Pilli R

    2009-05-01

    Full Text Available A comment is made on a recent letter published on Nature, in which different methodologies are applied to estimate the carbon balance of terrestrial ecosystems of China. A global carbon sink of 0.19-0.26 Pg per year is estimated during the 1980s and 1990s, and it is estimated that in 2006 terrestrial ecosystems have absorbed 28-37 per cent of global carbon emissions in China. Most of the carbon absorption is attributed to large-scale plantation made since the 1980s and shrub recovery. These results will certainly be valuable in the frame of the so-called “REDD” (Reducing Emissions from Deforestation forest Degradation in developing countries mechanism (UN convention on climate change UNFCCC.

  10. Land use related silica dynamics in terrestrial ecosystems.

    OpenAIRE

    Clymans, Wim

    2012-01-01

    Silicon (Si) provides the base component for well-balanced food-webs in aquatic systems. Here, together with nitrogen and phosphorous Si determines phytoplankton composition, and plays a major role in eutrophication problems and carbon sequestration. Rivers are the primary source of Si for the oceans, and is ultimately derived from mineral weathering. However there is growing evidence illustrating the importance of biological Si cycling in terrestrial ecosystems. Riverine Si fluxes will be af...

  11. Terrestrial Ecosystem Responses to Global Change: A Research Strategy

    Energy Technology Data Exchange (ETDEWEB)

    Ecosystems Working Group,

    1998-09-23

    Uncertainty about the magnitude of global change effects on terrestrial ecosystems and consequent feedbacks to the atmosphere impedes sound policy planning at regional, national, and global scales. A strategy to reduce these uncertainties must include a substantial increase in funding for large-scale ecosystem experiments and a careful prioritization of research efforts. Prioritization criteria should be based on the magnitude of potential changes in environmental properties of concern to society, including productivity; biodiversity; the storage and cycling of carbon, water, and nutrients; and sensitivity of specific ecosystems to environmental change. A research strategy is proposed that builds on existing knowledge of ecosystem responses to global change by (1) expanding the spatial and temporal scale of experimental ecosystem manipulations to include processes known to occur at large scales and over long time periods; (2) quantifying poorly understood linkages among processes through the use of experiments that manipulate multiple interacting environmental factors over a broader range of relevant conditions than did past experiments; and (3) prioritizing ecosystems for major experimental manipulations on the basis of potential positive and negative impacts on ecosystem properties and processes of intrinsic and/or utilitarian value to humans and on feedbacks of terrestrial ecosystems to the atmosphere. Models and experiments are equally important for developing process-level understanding into a predictive capability. To support both the development and testing of mechanistic ecosystem models, a two-tiered design of ecosystem experiments should be used. This design should include both (1) large-scale manipulative experiments for comprehensive testing of integrated ecosystem models and (2) multifactor, multilevel experiments for parameterization of process models across the critical range of interacting environmental factors (CO{sub 2}, temperature, water

  12. Pulses, linkages, and boundaries of coupled aquatic-terrestrial ecosystems

    Science.gov (United States)

    Tockner, K.

    2009-04-01

    Riverine floodplains are linked ecosystems where terrestrial and aquatic habitats overlap, creating a zone where they interact, the aquatic-terrestrial interface. The interface or boundary between aquatic and terrestrial habitats is an area of transition, contact or separation; and connectivity between these habitats may be defined as the ease with which organisms, matter or energy traverse these boundaries. Coupling of aquatic and terrestrial systems generates intertwining food webs, and we may predict that coupled systems are more productive than separated ones. For example, riparian consumers (aquatic and terrestrial) have alternative prey items external to their respective habitats. Such subsidized assemblages occupy a significant higher trophic position than assemblages in unsubsidized areas. Further, cross-habitat linkages are often pulsed; and even small pulses of a driver (e.g. short-term increases in flow) can cause major resource pulses (i.e. emerging aquatic insects) that control the recipient community. For example, short-term additions of resources, simulating pulsed inputs of aquatic food to terrestrial systems, suggest that due to resource partitioning and temporal separation among riparian arthropod taxa the resource flux from the river to the riparian zone increases with increasing riparian consumer diversity. I will discuss the multiple transfer and transformation processes of matter and organisms across aquatic-terrestrial habitats. Key landscape elements along river corridors are vegetated islands that function as instream riparian areas. Results from Central European rivers demonstrate that islands are in general more natural than fringing riparian areas, contribute substantially to total ecotone length, and create diverse habitats in the aquatic and terrestrial realm. In braided rivers, vegetated islands are highly productive landscape elements compared to the adjacent aquatic area. However, aquatic habitats exhibit a much higher decomposition

  13. Impacts of droughts on carbon sequestration by China's terrestrial ecosystems from 2000 to 2011

    Science.gov (United States)

    Liu, Y.; Zhou, Y.; Ju, W.; Wang, S.; Wu, X.; He, M.; Zhu, G.

    2014-05-01

    In recent years, China's terrestrial ecosystems have experienced frequent droughts. How these droughts have affected carbon sequestration by the terrestrial ecosystems is still unclear. In this study, the process-based Boreal Ecosystem Productivity Simulator (BEPS) model, driven by remotely sensed vegetation parameters, was employed to assess the effects of droughts on net ecosystem productivity (NEP) of terrestrial ecosystems in China from 2000 to 2011. Droughts of differing severity, as indicated by a standard precipitation index (SPI), hit terrestrial ecosystems in China extensively in 2001, 2006, 2009, and 2011. The national total annual NEP exhibited the slight decline of -11.3 Tg C yr-2 during the aforementioned years of extensive droughts. The NEP reduction ranged from 61.1 Tg C yr-1 to 168.8 Tg C yr-1. National and regional total NEP anomalies were correlated with the annual mean SPI, especially in Northwest China, North China, Central China, and Southwest China. The reductions in annual NEP in 2001 and 2011 might have been caused by a larger decrease in annual gross primary productivity (GPP) than in annual ecosystem respiration (ER). The reductions experienced in 2009 might be due to a decrease in annual GPP and an increase in annual ER, while reductions in 2006 could stem from a larger increase in ER than in GPP. The effects of droughts on NEP lagged up to 3-6 months, due to different responses of GPP and ER. In eastern China, where is humid and warm, droughts have predominant and short-term lagged influences on NEP. In western regions, cold and arid, the drought effects on NEP were relatively weaker but prone to lasting longer.

  14. Terrestrial Ecosystems - Land Surface Forms of the Conterminous United States

    Science.gov (United States)

    Cress, Jill J.; Sayre, Roger G.; Comer, Patrick; Warner, Harumi

    2009-01-01

    As part of an effort to map terrestrial ecosystems, the U.S. Geological Survey has generated land surface form classes to be used in creating maps depicting standardized, terrestrial ecosystem models for the conterminous United States, using an ecosystems classification developed by NatureServe . A biophysical stratification approach, developed for South America and now being implemented globally, was used to model the ecosystem distributions. Since land surface forms strongly influence the differentiation and distribution of terrestrial ecosystems, they are one of the key input layers in this biophysical stratification. After extensive investigation into various land surface form mapping methodologies, the decision was made to use the methodology developed by the Missouri Resource Assessment Partnership (MoRAP). MoRAP made modifications to Hammond's land surface form classification, which allowed the use of 30-meter source data and a 1-km2 window for analyzing the data cell and its surrounding cells (neighborhood analysis). While Hammond's methodology was based on three topographic variables, slope, local relief, and profile type, MoRAP's methodology uses only slope and local relief. Using the MoRAP method, slope is classified as gently sloping when more than 50 percent of the area in a 1-km2 neighborhood has slope less than 8 percent, otherwise the area is considered moderately sloping. Local relief, which is the difference between the maximum and minimum elevation in a neighborhood, is classified into five groups: 0-15 m, 16-30 m, 31-90 m, 91-150 m, and >150 m. The land surface form classes are derived by combining slope and local relief to create eight landform classes: flat plains (gently sloping and local relief = 90 m), low hills (not gently sloping and local relief = 150 m). However, in the USGS application of the MoRAP methodology, an additional local relief group was used (> 400 m) to capture additional local topographic variation. As a result, low

  15. Ash in fire affected ecosystems

    Science.gov (United States)

    Pereira, Paulo; Jordan, Antonio; Cerda, Artemi; Martin, Deborah

    2015-04-01

    Ash in fire affected ecosystems Ash lefts an important footprint in the ecosystems and has a key role in the immediate period after the fire (Bodi et al., 2014; Pereira et al., 2015). It is an important source of nutrients for plant recover (Pereira et al., 2014a), protects soil from erosion and controls soil hydrological process as runoff, infiltration and water repellency (Cerda and Doerr, 2008; Bodi et al., 2012, Pereira et al., 2014b). Despite the recognition of ash impact and contribution to ecosystems recuperation, it is assumed that we still have little knowledge about the implications of ash in fire affected areas. Regarding this situation we wanted to improve our knowledge in this field and understand the state of the research about fire ash around world. The special issue about "The role of ash in fire affected ecosystems" currently in publication in CATENA born from the necessity of joint efforts, identify research gaps, and discuss future cooperation in this interdisciplinary field. This is the first special issue about fire ash in the international literature. In total it will be published 10 papers focused in different aspects of the impacts of ash in fire affected ecosystems from several parts of the world: • Fire reconstruction using charcoal particles (Burjachs and Espositio, in press) • Ash slurries impact on rheological properties of Runoff (Burns and Gabet, in press) • Methods to analyse ash conductivity and sorbtivity in the laboratory and in the field (Balfour et al., in press) • Termogravimetric and hydrological properties of ash (Dlapa et al. in press) • Effects of ash cover in water infiltration (Leon et al., in press) • Impact of ash in volcanic soils (Dorta Almenar et al., in press; Escuday et al., in press) • Ash PAH and Chemical extracts (Silva et al., in press) • Microbiology (Barreiro et al., in press; Lombao et al., in press) We believe that this special issue will contribute importantly to the better understanding of

  16. The roles of productivity and ecosystem size in determining food chain length in tropical terrestrial ecosystems.

    Science.gov (United States)

    Young, Hillary S; McCauley, Douglas J; Dunbar, Robert B; Hutson, Michael S; Ter-Kuile, Ana Miller; Dirzo, Rodolfo

    2013-03-01

    Many different drivers, including productivity, ecosystem size, and disturbance, have been considered to explain natural variation in the length of food chains. Much remains unknown about the role of these various drivers in determining food chain length, and particularly about the mechanisms by which they may operate in terrestrial ecosystems, which have quite different ecological constraints than aquatic environments, where most food chain length studies have been thus far conducted. In this study, we tested the relative importance of ecosystem size and productivity in influencing food chain length in a terrestrial setting. We determined that (1) there is no effect of ecosystem size or productive space on food chain length; (2) rather, food chain length increases strongly and linearly with productivity; and (3) the observed changes in food chain length are likely achieved through a combination of changes in predator size, predator behavior, and consumer diversity along gradients in productivity. These results lend new insight into the mechanisms by which productivity can drive changes in food chain length, point to potential for systematic differences in the drivers of food web structure between terrestrial and aquatic systems, and challenge us to consider how ecological context may control the drivers that shape food chain length.

  17. Evaluation of atmospheric aerosol and tropospheric ozone effects on global terrestrial ecosystem carbon dynamics

    Science.gov (United States)

    Chen, Min

    period of 2003-2010. Ecosystem heterotrophic respiration (RH) was negatively affected by the aerosol loading. These results support previous conclusions of the advantage of aerosol light scattering effect on plant productions in other studies but suggest there is strong spatial variation. This study finds indirect aerosol effects on terrestrial ecosystem carbon dynamics through affecting plant phenology, thermal and hydrological environments. All these evidences suggested that the aerosol direct radiative effect on global terrestrial ecosystem carbon dynamics should be considered to better understand the global carbon cycle and climate change. An ozone sub-model is developed in this dissertation and fully coupled with iTem. The coupled model, named iTemO3 considers the processes of ozone stomatal deposition, plant defense to ozone influx, ozone damage and plant repairing mechanism. By using a global atmospheric chemical transport model (GACTM) estimated ground-level ozone concentration data, the model estimated global annual stomatal ozone deposition is 234.0 Tg O3 yr-1 and indicates which regions have high ozone damage risk. Different plant functional types, sunlit and shaded leaves are shown to have different responses to ozone. The model predictions suggest that ozone has caused considerable change on global terrestrial ecosystem carbon storage and carbon exchanges over the study period 2004-2008. The study suggests that uncertainty of the key parameters in iTemO3 could result in large errors in model predictions. Thus more experimental data for better model parameterization is highly needed.

  18. The terrestrial ecosystem program for the Yucca Mountain Project

    International Nuclear Information System (INIS)

    Ostler, W.K.; O'Farrell, T.P.

    1994-01-01

    DOE has implemented a program to monitor and mitigate impacts associated with site Characterization Activities at Yucca Mountain on the environment. This program has a sound experimental and statistical base. Monitoring data has been collected for parts of the program since 1989. There have been numerous changes in the Terrestrial Ecosystems Program since 1989 that reflect changes in the design and locations of Site Characterization Activities. There have also been changes made in the mitigation techniques implemented to protect important environmental resources based on results from the research efforts at Yucca Mountain. These changes have strengthened DOE efforts to ensure protection of the environmental during Site Characterization. DOE,has developed and implemented an integrated environmental program that protects the biotic environment and will restore environmental quality at Yucca Mountain

  19. Function of Wildfire-Deposited Pyrogenic Carbon in Terrestrial Ecosystems

    Directory of Open Access Journals (Sweden)

    Melissa R. A. Pingree

    2017-08-01

    Full Text Available Fire is an important driver of change in most forest, savannah, and prairie ecosystems and fire-altered organic matter, or pyrogenic carbon (PyC, conveys numerous functions in soils of fire-maintained terrestrial ecosystems. Although an exceptional number of recent review articles and books have addressed agricultural soil application of charcoal or biochar, few reviews have addressed the functional role of naturally formed PyC in fire-maintained ecosystems. Recent advances in molecular spectroscopic techniques have helped strengthen our understanding of PyC as a ubiquitous, complex material that is capable of altering soil chemical, physical, and biological properties and processes. The uniquely recalcitrant nature of PyC in soils is partly a result of its stable C = C double-bonded, graphene-like structure and C-rich, N-poor composition. This attribute allows it to persist in soils for hundreds to thousands of years and represent net ecosystem C sequestration in fire-maintained ecosystems. The rapid formation of PyC during wildfire or anthropogenic fire events short-circuits the normally tortuous pathway of recalcitrant soil C formation. Existing literature also suggests that PyC provides an essential role in the cycling of certain nutrients, greatly extending the timeframe by which fires influence soil processes and facilitating recovery in ecosystems where organic matter inputs are low and post-fire surface soil bacterial and fungal activity is reduced. The high surface area of PyC allows for the adsorption a broad spectrum of organic compounds that directly or indirectly influence microbial processes after fire events. Adsorption capacity and microsite conditions created by PyC yields a “charosphere” effect in soil with heightened microbial activity in the vicinity of PyC. In this mini-review, we explore the function of PyC in natural and semi-natural settings, provide a mechanistic approach to understanding these functions, and examine

  20. USING ANT COMMUNITIES FOR RAPID ASSESSMENT OF TERRESTRIAL ECOSYSTEM HEALTH

    Energy Technology Data Exchange (ETDEWEB)

    Wike, L; Doug Martin, D; Michael Paller, M; Eric Nelson, E

    2007-01-12

    Ecosystem health with its near infinite number of variables is difficult to measure, and there are many opinions as to which variables are most important, most easily measured, and most robust, Bioassessment avoids the controversy of choosing which physical and chemical parameters to measure because it uses responses of a community of organisms that integrate all aspects of the system in question. A variety of bioassessment methods have been successfully applied to aquatic ecosystems using fish and macroinvertebrate communities. Terrestrial biotic index methods are less developed than those for aquatic systems and we are seeking to address this problem here. This study had as its objective to examine the baseline differences in ant communities at different seral stages from clear cut back to mature pine plantation as a precursor to developing a bioassessment protocol. Comparative sampling was conducted at four seral stages; clearcut, 5 year, 15 year and mature pine plantation stands. Soil and vegetation data were collected at each site. All ants collected were preserved in 70% ethyl alcohol and identified to genus. Analysis of the ant data indicates that ants respond strongly to the habitat changes that accompany ecological succession in managed pine forests and that individual genera as well as ant community structure can be used as an indicator of successional change. Ants exhibited relatively high diversity in both early and mature seral stages. High ant diversity in the mature seral stages was likely related to conditions on the forest floor which favored litter dwelling and cool climate specialists.

  1. Application of a terrestrial ecosystem model (ORCHIDEE-STICS) in simulating energy and CO2 fluxes in Asian rice croplands

    Science.gov (United States)

    Wang, X.; Piao, S.; Ciais, P.; Vuichard, N.

    2012-12-01

    Process-based terrestrial ecosystem models have shown great potentials in predicting the response of managed ecosystems to environmental changes. However, the simulated water and carbon fluxes over rice ecosystems in tropical Asia are still subject to large uncertainties, partly due to poorly constrained parameters in the models. Here, a terrestrial ecosystem model incorporating a more realistic crop module (ORCHIDEE-STICS) was calibrated against in-situ flux data and observed and remotely sensed leaf area indexes over rice ecosystems in Asia. The key parameters adjusted include maximum photosynthetic carboxylation rate (Vcmax) and electron transport rate (Vjmax), temperature sensitivity of heterotrophic respiration (Q10) and a series of critical thresholds for different crop development stages. Compared with the observations, the calibrated model more realistically simulated the seasonal and year-to-year variation of the observed water and carbon fluxes with reductions in the root mean square difference and better timing in the crop development stages. Sensitivity tests further reveal that management practices like the timing of transplanting and draining could affect the seasonal and inter-annual variation of the net carbon exchange, suggesting that the absence of explicit accounting the change of management practices in the terrestrial ecosystem models may induce large uncertainties in predicting cropland ecosystem response to future climate change.

  2. Isotopic identification of nitrogen hotspots across natural terrestrial ecosystems

    Directory of Open Access Journals (Sweden)

    E. Bai

    2012-08-01

    Full Text Available Nitrogen (N influences local biological processes, ecosystem productivity, the composition of the atmospheric-climate system, and the human endeavour as a whole. Here we use natural variations in N isotopes, coupled with two models, to trace global pathways of N loss from the land to the water and atmosphere. We show that denitrification accounts for approximately 35 % of total N losses from the natural soil, with NO, N2O, and N2 fluxes equal to 15.7 ± 4.7 Tg N yr−1, 10.2 ± 3.0 Tg N yr−1, and 21.0 ± 6.1 Tg N yr−1, respectively. Our analysis points to tropical regions as the major "hotspot" of nitrogen export from the terrestrial biosphere, accounting for 71 % of global N losses from the natural land surface. The poorly studied Congo Basin is further identified as one of the major natural sources of atmospheric N2O. Extra-tropical areas, by contrast, lose a greater fraction of N via leaching pathways (~77 % of total N losses than do tropical biomes, likely contributing to N limitations of CO2 uptake at higher latitudes. Our results provide an independent constraint on global models of the N cycle among different regions of the unfertilized biosphere.

  3. Developing Conceptual Models for Assessing Climate Change Impacts to Contaminant Availability in Terrestrial Ecosystems

    Science.gov (United States)

    2015-03-01

    Greenberg 2005), effects of dredged material (PIANC 2006), and ecosystem restoration (Fischenich 2008) among others. The process of developing a conceptual...Impacts to Contaminant Availability in Terrestrial Ecosystems by Burton C. Suedel, Nathan R. Beane, Eric R. Britzke, Cheryl R. Montgomery, and...are generally project or problem specific. Building a CM includes determining the components of the ecosystem , identifying relationships linking these

  4. How do persistent organic pollutants be coupled with biogeochemical cycles of carbon and nutrients in terrestrial ecosystems under global climate change?

    Energy Technology Data Exchange (ETDEWEB)

    Teng, Ying [Chinese Academy of Sciences, Nanjing (China). Key Lab. of Soil Environment and Pollution Remediation; Griffith Univ., Nathan, QLD (Australia). Environmetnal Futures Centre and School of Biomolecular and Physical Sciences; Xu, Zhihong; Reverchon, Frederique [Griffith Univ., Nathan, QLD (Australia). Environmetnal Futures Centre and School of Biomolecular and Physical Sciences; Luo, Yongming [Chinese Academy of Sciences, Nanjing (China). Key Lab. of Soil Environment and Pollution Remediation

    2012-03-15

    Global climate change (GCC), especially global warming, has affected the material cycling (e.g., carbon, nutrients, and organic chemicals) and the energy flows of terrestrial ecosystems. Persistent organic pollutants (POPs) were regarded as anthropogenic organic carbon (OC) source, and be coupled with the natural carbon (C) and nutrient biogeochemical cycling in ecosystems. The objective of this work was to review the current literature and explore potential coupling processes and mechanisms between POPs and biogeochemical cycles of C and nutrients in terrestrial ecosystems induced by global warming. Global warming has caused many physical, chemical, and biological changes in terrestrial ecosystems. POPs environmental fate in these ecosystems is controlled mainly by temperature and biogeochemical processes. Global warming may accelerate the re-emissions and redistribution of POPs among environmental compartments via soil-air exchange. Soil-air exchange is a key process controlling the fate and transportation of POPs and terrestrial ecosystem C at regional and global scales. Soil respiration is one of the largest terrestrial C flux induced by microbe and plant metabolism, which can affect POPs biotransformation in terrestrial ecosystems. Carbon flow through food web structure also may have important consequences for the biomagnification of POPs in the ecosystems and further lead to biodiversity loss induced by climate change and POPs pollution stress. Moreover, the integrated techniques and biological adaptation strategy help to fully explore the coupling mechanisms, functioning and trends of POPs and C and nutrient biogeochemical cycling processes in terrestrial ecosystems. There is increasing evidence that the environmental fate of POPs has been linked with biogeochemical cycles of C and nutrients in terrestrial ecosystems under GCC. However, the relationships between POPs and the biogeochemical cycles of C and nutrients are still not well understood. Further

  5. Microbial characterization of toluene-degrading denitrifying consortia obtained from terrestrial and marine ecosystems.

    Science.gov (United States)

    An, Y-J; Joo, Y-H; Hong, I-Y; Ryu, H-W; Cho, K-S

    2004-10-01

    The degradation characteristics of toluene coupled to nitrate reduction were investigated in enrichment culture and the microbial communities of toluene-degrading denitrifying consortia were characterized by denaturing gradient gel electrophoresis (DGGE) technique. Anaerobic nitrate-reducing bacteria were enriched from oil-contaminated soil samples collected from terrestrial (rice field) and marine (tidal flat) ecosystems. Enriched consortia degraded toluene in the presence of nitrate as a terminal electron acceptor. The degradation rate of toluene was affected by the initial substrate concentration and co-existence of other hydrocarbons. The types of toluene-degrading denitrifying consortia depended on the type of ecosystem. The clone RS-7 obtained from the enriched consortium of the rice field was most closely related to a toluene-degrading and denitrifying bacterium, Azoarcus denitrificians (A. tolulyticus sp. nov.). The clone TS-11 detected in the tidal flat enriched consortium was affiliated to Thauera sp. strain S2 (T. aminoaromatica sp. nov.) that was able to degrade toluene under denitrifying conditions. This indicates that environmental factors greatly influence microbial communities obtained from terrestrial (rice field) and marine (tidal flat) ecosystems.

  6. Linking Biological Responses of Terrestrial N Eutrophication to the Final Ecosystem Goods and Services Classification System

    Science.gov (United States)

    Bell, M. D.; Clark, C.; Blett, T.

    2015-12-01

    The response of a biological indicator to N deposition can indicate that an ecosystem has surpassed a critical load and is at risk of significant change. The importance of this exceedance is often difficult to digest by policy makers and public audiences if the change is not linked to a familiar ecosystem endpoint. A workshop was held to bring together scientists, resource managers, and policy makers with expertise in ecosystem functioning, critical loads, and economics in an effort to identify the ecosystem services impacted by air pollution. This was completed within the framework of the Final Ecosystem Goods and Services (FEGS) Classification System to produce a product that identified distinct interactions between society and the effects of nitrogen pollution. From each change in a biological indicator, we created multiple ecological production functions to identify the cascading effects of the change to a measureable ecosystem service that a user interacts with either by enjoying, consuming, or appreciating the good or service, or using it as an input in the human economy. This FEGS metric was then linked to a beneficiary group that interacts with the service. Chains detailing the links from the biological indicator to the beneficiary group were created for aquatic and terrestrial acidification and eutrophication at the workshop, and here we present a subset of the workshop results by highlighting for 9 different ecosystems affected by terrestrial eutrophication. A total of 213 chains that linked to 37 unique FEGS metrics and impacted 15 beneficiary groups were identified based on nitrogen deposition mediated changes to biological indicators. The chains within each ecosystem were combined in flow charts to show the complex, overlapping relationships among biological indicators, ecosystem services, and beneficiary groups. Strength of relationship values were calculated for each chain based on support for the link in the scientific literature. We produced the

  7. Trends in land surface phenology and atmospheric CO2 seasonality in the Northern Hemisphere terrestrial ecosystems

    Science.gov (United States)

    Gonsamo, A.; Chen, J. M.

    2017-12-01

    Northern terrestrial ecosystems have shown global warming-induced advances in start, delays in end, and thus increased lengths of growing season and gross photosynthesis in recent decades. The tradeoffs between seasonal dynamics of two opposing fluxes, CO2 uptake through photosynthesis and release through respiration, determine the influence of the terrestrial ecosystems on the atmospheric CO2 concentration and 13C/12C isotope ratio seasonality. Atmospheric CO2 and 13C/12C seasonality is controlled by vegetation phenology, but is not identical because growth will typically commence some time before and terminate some time after the net carbon exchange changes sign in spring and autumn, respectively. Here, we use 34-year satellite normalized difference vegetation index (NDVI) observations to determine how changes in vegetation productivity and phenology affect both the atmospheric CO2 and 13C/12C seasonality. Differences and similarities in recent trends of CO2 and 13C/12C seasonality and vegetation phenology will be discussed. Furthermore, we use the NDVI observations, and atmospheric CO2 and 13C/12C data to show the trends and variability of the timing of peak season plant activity. Preliminary results show that the peak season plant activity of the Northern Hemisphere extra-tropical terrestrial ecosystems is shifting towards spring, largely in response to the warming-induced advance of the start of growing season. Besides, the spring-ward shift of the peak plant activity is contributing the most to the increasing peak season productivity. In other words, earlier start of growing season is highly linked to earlier arrival of peak of season and higher NDVI. Changes in the timing of peak season plant activity are expected to disrupt the synchrony of biotic interaction and exert strong biophysical feedbacks on climate by modifying the surface albedo and energy budget.

  8. Mitigation of greenhouse gases emissions impact and their influence on terrestrial ecosystem.

    Science.gov (United States)

    Wójcik Oliveira, K.; Niedbała, G.

    2018-05-01

    Nowadays, one of the most important challenges faced by the humanity in the current century is the increasing temperature on Earth, caused by a growing emission of greenhouse gases into the atmosphere. Terrestrial ecosystems, as an important component of the carbon cycle, play an important role in the sequestration of carbon, which is a chance to improve the balance of greenhouse gases. Increasing CO2 absorption by terrestrial ecosystems is one way to reduce the atmospheric CO2 emissions. Sequestration of CO2 by terrestrial ecosystems is not yet fully utilized method of mitigating CO2 emission to the atmosphere. Terrestrial ecosystems, especially forests, are essential for the regulation of CO2 content in the atmosphere and more attention should be paid to seeking the natural processes of CO2 sequestration.

  9. A terrestrial ecosystem model (SOLVEG) coupled with atmospheric gas and aerosol exchange processes

    International Nuclear Information System (INIS)

    Katata, Genki; Ota, Masakazu

    2017-01-01

    In order to predict the impact of atmospheric pollutants (gases and aerosols) to the terrestrial ecosystem, new schemes for calculating the processes of dry deposition of gases and aerosols, and water and carbon cycles in terrestrial ecosystems were implemented in the one-dimensional atmosphere-SOiL-VEGetation model, SOLVEG. We made performance tests at various vegetation areas to validate the newly developed schemes. In this report, the detail in each modeled process is described with an instruction how to use the modified SOLVEG. The framework of 'terrestrial ecosystem model' was developed for investigation of a change in water, energy, and carbon cycles associated with global warming and air pollution and its impact on terrestrial ecosystems. (author)

  10. Responses of terrestrial ecosystems' net primary productivity to future regional climate change in China.

    Science.gov (United States)

    Zhao, Dongsheng; Wu, Shaohong; Yin, Yunhe

    2013-01-01

    The impact of regional climate change on net primary productivity (NPP) is an important aspect in the study of ecosystems' response to global climate change. China's ecosystems are very sensitive to climate change owing to the influence of the East Asian monsoon. The Lund-Potsdam-Jena Dynamic Global Vegetation Model for China (LPJ-CN), a global dynamical vegetation model developed for China's terrestrial ecosystems, was applied in this study to simulate the NPP changes affected by future climate change. As the LPJ-CN model is based on natural vegetation, the simulation in this study did not consider the influence of anthropogenic activities. Results suggest that future climate change would have adverse effects on natural ecosystems, with NPP tending to decrease in eastern China, particularly in the temperate and warm temperate regions. NPP would increase in western China, with a concentration in the Tibetan Plateau and the northwest arid regions. The increasing trend in NPP in western China and the decreasing trend in eastern China would be further enhanced by the warming climate. The spatial distribution of NPP, which declines from the southeast coast to the northwest inland, would have minimal variation under scenarios of climate change.

  11. Responses of terrestrial ecosystems' net primary productivity to future regional climate change in China.

    Directory of Open Access Journals (Sweden)

    Dongsheng Zhao

    Full Text Available The impact of regional climate change on net primary productivity (NPP is an important aspect in the study of ecosystems' response to global climate change. China's ecosystems are very sensitive to climate change owing to the influence of the East Asian monsoon. The Lund-Potsdam-Jena Dynamic Global Vegetation Model for China (LPJ-CN, a global dynamical vegetation model developed for China's terrestrial ecosystems, was applied in this study to simulate the NPP changes affected by future climate change. As the LPJ-CN model is based on natural vegetation, the simulation in this study did not consider the influence of anthropogenic activities. Results suggest that future climate change would have adverse effects on natural ecosystems, with NPP tending to decrease in eastern China, particularly in the temperate and warm temperate regions. NPP would increase in western China, with a concentration in the Tibetan Plateau and the northwest arid regions. The increasing trend in NPP in western China and the decreasing trend in eastern China would be further enhanced by the warming climate. The spatial distribution of NPP, which declines from the southeast coast to the northwest inland, would have minimal variation under scenarios of climate change.

  12. Dual role of lignin in plant litter decomposition in terrestrial ecosystems.

    Science.gov (United States)

    Austin, Amy T; Ballaré, Carlos L

    2010-03-09

    Plant litter decomposition is a critical step in the formation of soil organic matter, the mineralization of organic nutrients, and the carbon balance in terrestrial ecosystems. Biotic decomposition in mesic ecosystems is generally negatively correlated with the concentration of lignin, a group of complex aromatic polymers present in plant cell walls that is recalcitrant to enzymatic degradation and serves as a structural barrier impeding microbial access to labile carbon compounds. Although photochemical mineralization of carbon has recently been shown to be important in semiarid ecosystems, litter chemistry controls on photodegradative losses are not understood. We evaluated the importance of litter chemistry on photodegradation of grass litter and cellulose substrates with varying levels of lignin [cellulose-lignin (CL) substrates] under field conditions. Using wavelength-specific light attenuation filters, we found that light-driven mass loss was promoted by both UV and visible radiation. The spectral dependence of photodegradation correlated with the absorption spectrum of lignin but not of cellulose. Field incubations demonstrated that increasing lignin concentration reduced biotic decomposition, as expected, but linearly increased photodegradation. In addition, lignin content in CL substrates consistently decreased in photodegradative incubations. We conclude that lignin has a dual role affecting litter decomposition, depending on the dominant driver (biotic or abiotic) controlling carbon turnover. Under photodegradative conditions, lignin is preferentially degraded because it acts as an effective light-absorbing compound over a wide range of wavelengths. This mechanistic understanding of the role of lignin in plant litter decomposition will allow for more accurate predictions of carbon dynamics in terrestrial ecosystems.

  13. The Limits of Acclimation of land plants in a Terrestrial Ecosystems Model

    Science.gov (United States)

    Kothavala, Zavareh

    2014-05-01

    In this study, we examine the role of the terrestrial carbon cycle and the ability of different plant types to acclimate to a changing climate at the centennial scale using a global ecosystems model with updated biogeochemical processes related to moisture, carbon, and nitrogen. Elevated level of atmospheric carbon dioxide (CO2) increases CO2 fertilization, resulting in more CO2 uptake by vegetation, whereas the concomitant warming increases autotrophic and heterotrophic respiration, releasing CO2 to the atmosphere. Additionally, warming will enhance photosynthesis if current temperatures are below the optimal temperature for plant growth, while it will reduce photosynthesis if current temperatures are above the optimal temperature for plant growth. We present a series of ensemble simulations to evaluate the ability of plants to acclimate to changing conditions over the last century and how this affects the terrestrial carbon sink. A set of experiments related to (a) the varying relationship between CO2 fertilization and the half saturation constant, (b) the factors related to gross primary productivity and maintenance respiration, and (c) the variables related to heterotrophic respiration, were conducted with thirteen plant functional types. The experiments were performed using the Terrestrial Ecosystem Model (TEM) with a present-day vegetation distribution without the effects of natural or human disturbance, and a closed Nitrogen cycle, at a half-degree resolution over the globe. The experiment design consisted of eight scenarios that are consistent with past and future ecosystem conditions, presented in other scientific studies. The significance of model trends related to runoff, soil moisture, soil carbon, Net Primary Productivity (NPP), crop yield, and Net Ecosystem Productivity (NEP) for different seasons, as well as surface temperature, precipitation, vapor pressure, and photosynthetically active radiation are analyzed for various ecosystems at the global

  14. Assessing net ecosystem carbon exchange of U S terrestrial ecosystems by integrating eddy covariance flux measurements and satellite observations

    Energy Technology Data Exchange (ETDEWEB)

    Zhuang, Qianlai [Purdue University; Law, Beverly E. [Oregon State University; Baldocchi, Dennis [University of California, Berkeley; Ma, Siyan [University of California, Berkeley; Chen, Jiquan [University of Toledo, Toledo, OH; Richardson, Andrew [Harvard University; Melillo, Jerry [Marine Biological Laboratory; Davis, Ken J. [Pennsylvania State University; Hollinger, D. [USDA Forest Service; Wharton, Sonia [University of California, Davis; Falk, Matthias [University of California, Davis; Paw, U. Kyaw Tha [University of California, Davis; Oren, Ram [Duke University; Katulk, Gabriel G. [Duke University; Noormets, Asko [North Carolina State University; Fischer, Marc [Lawrence Berkeley National Laboratory (LBNL); Verma, Shashi [University of Nebraska; Suyker, A. E. [University of Nebraska, Lincoln; Cook, David R. [Argonne National Laboratory (ANL); Sun, G. [USDA Forest Service; McNulty, Steven G. [USDA Forest Service; Wofsy, Steve [Harvard University; Bolstad, Paul V [University of Minnesota; Burns, Sean [University of Colorado, Boulder; Monson, Russell K. [University of Colorado, Boulder; Curtis, Peter [Ohio State University, The, Columbus; Drake, Bert G. [Smithsonian Environmental Research Center, Edgewater, MD; Foster, David R. [Harvard University; Gu, Lianhong [ORNL; Hadley, Julian L. [Harvard University; Litvak, Marcy [University of New Mexico, Albuquerque; Martin, Timothy A. [University of Florida, Gainesville; Matamala, Roser [Argonne National Laboratory (ANL); Meyers, Tilden [NOAA, Oak Ridge, TN; Oechel, Walter C. [San Diego State University; Schmid, H. P. [Indiana University; Scott, Russell L. [USDA ARS; Torn, Margaret S. [Lawrence Berkeley National Laboratory (LBNL)

    2011-01-01

    More accurate projections of future carbon dioxide concentrations in the atmosphere and associated climate change depend on improved scientific understanding of the terrestrial carbon cycle. Despite the consensus that U.S. terrestrial ecosystems provide a carbon sink, the size, distribution, and interannual variability of this sink remain uncertain. Here we report a terrestrial carbon sink in the conterminous U.S. at 0.63 pg C yr 1 with the majority of the sink in regions dominated by evergreen and deciduous forests and savannas. This estimate is based on our continuous estimates of net ecosystem carbon exchange (NEE) with high spatial (1 km) and temporal (8-day) resolutions derived from NEE measurements from eddy covariance flux towers and wall-to-wall satellite observations from Moderate Resolution Imaging Spectroradiometer (MODIS). We find that the U.S. terrestrial ecosystems could offset a maximum of 40% of the fossil-fuel carbon emissions. Our results show that the U.S. terrestrial carbon sink varied between 0.51 and 0.70 pg C yr 1 over the period 2001 2006. The dominant sources of interannual variation of the carbon sink included extreme climate events and disturbances. Droughts in 2002 and 2006 reduced the U.S. carbon sink by 20% relative to a normal year. Disturbances including wildfires and hurricanes reduced carbon uptake or resulted in carbon release at regional scales. Our results provide an alternative, independent, and novel constraint to the U.S. terrestrial carbon sink.

  15. The adaptation rate of terrestrial ecosystems as a critical factor in global climate dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Fuessler, J S; Gassmann, F [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    A conceptual climate model describing regional two-way atmosphere-vegetation interaction has been extended by a simple qualitative scheme of ecosystem adaptation to drought stress. The results of this explorative study indicate that the role of terrestrial vegetation under different forcing scenarios depends crucially on the rate of the ecosystems adaptation to drought stress. The faster the adaptation of important ecosystems such as forests the better global climate is protected from abrupt climate changes. (author) 1 fig., 3 refs.

  16. Microplastics in the terrestrial ecosystem: Implications for Lumbricus terrestris (Oligochaeta, Lumbricidae)

    NARCIS (Netherlands)

    Huerta Lwanga, Esperanza; Gertsen, H.F.; Gooren, H.; Peters, P.D.; Salanki, T.E.; Ploeg, van der M.J.C.; Besseling, E.; Koelmans, A.A.; Geissen, V.

    2016-01-01

    Plastic debris is widespread in the environment, but information on the effects of microplastics on terrestrial fauna is completely lacking. Here, we studied the survival and fitness of the earthworm Lumbricus terrestris (Oligochaeta, Lumbricidae) exposed to microplastics (Polyethylene, <150 μm)

  17. Importance of terrestrial arthropods as subsidies in lowland Neotropical rain forest stream ecosystems

    Science.gov (United States)

    Small, Gaston E.; Torres, Pedro J.; Schwizer, Lauren M.; Duff, John H.; Pringle, Catherine M.

    2013-01-01

    The importance of terrestrial arthropods has been documented in temperate stream ecosystems, but little is known about the magnitude of these inputs in tropical streams. Terrestrial arthropods falling from the canopy of tropical forests may be an important subsidy to tropical stream food webs and could also represent an important flux of nitrogen (N) and phosphorus (P) in nutrient-poor headwater streams. We quantified input rates of terrestrial insects in eight streams draining lowland tropical wet forest in Costa Rica. In two focal headwater streams, we also measured capture efficiency by the fish assemblage and quantified terrestrially derived N- and P-excretion relative to stream nutrient uptake rates. Average input rates of terrestrial insects ranged from 5 to 41 mg dry mass/m2/d, exceeding previous measurements of aquatic invertebrate secondary production in these study streams, and were relatively consistent year-round, in contrast to values reported in temperate streams. Terrestrial insects accounted for half of the diet of the dominant fish species, Priapicthys annectens. Although terrestrially derived fish excretion was found to be a small flux relative to measured nutrient uptake rates in the focal streams, the efficient capture and processing of terrestrial arthropods by fish made these nutrients available to the local stream ecosystem. This aquatic-terrestrial linkage is likely being decoupled by deforestation in many tropical regions, with largely unknown but potentially important ecological consequences.

  18. Terrestrial Ecosystem Responses to Species Gains and Losses

    NARCIS (Netherlands)

    Wardle, D.A.; Bardgett, R.D.; Callaway, R.; Putten, van der W.H.

    2011-01-01

    Ecosystems worldwide are losing some species and gaining others, resulting in an interchange of species that is having profound impacts on how these ecosystems function. However, research on the effects of species gains and losses has developed largely independently of one another. Recent conceptual

  19. Terrestrial ecosystem responses to species gains and losses

    NARCIS (Netherlands)

    Wardle, D.A.; Bardgett, R.D.; Callaway, R.M.; Van der Putten, W.H.

    2011-01-01

    Ecosystems worldwide are losing some species and gaining others, resulting in an interchange of species that is having profound impacts on how these ecosystems function. However, research on the effects of species gains and losses has developed largely independently of one another. Recent conceptual

  20. Comparing marine and terrestrial ecosystems: Implications for the design of coastal marine reserves

    Science.gov (United States)

    Carr, M.H.; Neigel, J.E.; Estes, J.A.; Andelman, S.; Warner, R.R.; Largier, J. L.

    2003-01-01

    Concepts and theory for the design and application of terrestrial reserves is based on our understanding of environmental, ecological, and evolutionary processes responsible for biological diversity and sustainability of terrestrial ecosystems and how humans have influenced these processes. How well this terrestrial-based theory can be applied toward the design and application of reserves in the coastal marine environment depends, in part, on the degree of similarity between these systems. Several marked differences in ecological and evolutionary processes exist between marine and terrestrial ecosystems as ramifications of fundamental differences in their physical environments (i.e., the relative prevalence of air and water) and contemporary patterns of human impacts. Most notably, the great extent and rate of dispersal of nutrients, materials, holoplanktonic organisms, and reproductive propagules of benthic organisms expand scales of connectivity among near-shore communities and ecosystems. Consequently, the "openness" of marine populations, communities, and ecosystems probably has marked influences on their spatial, genetic, and trophic structures and dynamics in ways experienced by only some terrestrial species. Such differences appear to be particularly significant for the kinds of organisms most exploited and targeted for protection in coastal marine ecosystems (fishes and macroinvertebrates). These and other differences imply some unique design criteria and application of reserves in the marine environment. In explaining the implications of these differences for marine reserve design and application, we identify many of the environmental and ecological processes and design criteria necessary for consideration in the development of the analytical approaches developed elsewhere in this Special Issue.

  1. Biogeochemical cycling in terrestrial ecosystems of the Caatinga Biome.

    Science.gov (United States)

    Menezes, R S C; Sampaio, E V S B; Giongo, V; Pérez-Marin, A M

    2012-08-01

    The biogeochemical cycles of C, N, P and water, the impacts of land use in the stocks and flows of these elements and how they can affect the structure and functioning of Caatinga were reviewed. About half of this biome is still covered by native secondary vegetation. Soils are deficient in nutrients, especially N and P. Average concentrations of total soil P and C in the top layer (0-20 cm) are 196 mg kg(-1) and 9.3 g kg(-1), corresponding to C stocks around 23 Mg ha(-1). Aboveground biomass of native vegetation varies from 30 to 50 Mg ha(-1), and average root biomass from 3 to 12 Mg ha(-1). Average annual productivities and biomass accumulation in different land use systems vary from 1 to 7 Mg ha(-1) year(-1). Biological atmospheric N2 fixation is estimated to vary from 3 to 11 kg N ha(-1) year-1 and 21 to 26 kg N ha(-1) year(-1) in mature and secondary Caatinga, respectively. The main processes responsible for nutrient and water losses are fire, soil erosion, runoff and harvest of crops and animal products. Projected climate changes in the future point to higher temperatures and rainfall decreases. In face of the high intrinsic variability, actions to increase sustainability should improve resilience and stability of the ecosystems. Land use systems based on perennial species, as opposed to annual species, may be more stable and resilient, thus more adequate to face future potential increases in climate variability. Long-term studies to investigate the potential of the native biodiversity or adapted exotic species to design sustainable land use systems should be encouraged.

  2. Implications of Uncertainty in Fossil Fuel Emissions for Terrestrial Ecosystem Modeling

    Science.gov (United States)

    King, A. W.; Ricciuto, D. M.; Mao, J.; Andres, R. J.

    2017-12-01

    Given observations of the increase in atmospheric CO2, estimates of anthropogenic emissions and models of oceanic CO2 uptake, one can estimate net global CO2 exchange between the atmosphere and terrestrial ecosystems as the residual of the balanced global carbon budget. Estimates from the Global Carbon Project 2016 show that terrestrial ecosystems are a growing sink for atmospheric CO2 (averaging 2.12 Gt C y-1 for the period 1959-2015 with a growth rate of 0.03 Gt C y-1 per year) but with considerable year-to-year variability (standard deviation of 1.07 Gt C y-1). Within the uncertainty of the observations, emissions estimates and ocean modeling, this residual calculation is a robust estimate of a global terrestrial sink for CO2. A task of terrestrial ecosystem science is to explain the trend and variability in this estimate. However, "within the uncertainty" is an important caveat. The uncertainty (2σ; 95% confidence interval) in fossil fuel emissions is 8.4% (±0.8 Gt C in 2015). Combined with uncertainty in other carbon budget components, the 2σ uncertainty surrounding the global net terrestrial ecosystem CO2 exchange is ±1.6 Gt C y-1. Ignoring the uncertainty, the estimate of a general terrestrial sink includes 2 years (1987 and 1998) in which terrestrial ecosystems are a small source of CO2 to the atmosphere. However, with 2σ uncertainty, terrestrial ecosystems may have been a source in as many as 18 years. We examine how well global terrestrial biosphere models simulate the trend and interannual variability of the global-budget estimate of the terrestrial sink within the context of this uncertainty (e.g., which models fall outside the 2σ uncertainty and in what years). Models are generally capable of reproducing the trend in net terrestrial exchange, but are less able to capture interannual variability and often fall outside the 2σ uncertainty. The trend in the residual carbon budget estimate is primarily associated with the increase in atmospheric CO2

  3. The impacts of past climate change on terrestrial and aquatic ecosystems

    International Nuclear Information System (INIS)

    Bradshaw, R.H.W.; Anderson, N.J.

    2001-01-01

    The last two million years of global history have been dominated by the impacts of rapid climate change. This influence is not immediately obvious to most biologists whose observations rarely extend beyond a period of a few years, but becomes apparent when interpreting long-term data sets whether they be population studies or palaeoecological data. It is appropriate therefore to consider how terrestrial and aquatic ecosystems have responded to climate change during the Quaternary when speculating about response to future climatic developments. In this chapter we discuss and illustrate the complex interactions between climate and anthropogenic influence on terrestrial and aquatic ecosystems during the Holocene. Climate influences ecosystems both directly (e.g. physiological responses or lake thermal stratification) and indirectly (e.g. via fire frequency or catchment hydrology). Lake sediments can be used to study both past climatic change directly and the effects of past climatic variability. In this chapter we present summary examples of the influence of past climate change on terrestrial and aquatic ecosystems as well showing how lake sediment records can provide proxy records of past climate change. The geological record from the last 18 000 years documents large changes in terrestrial and aquatic ecosystems that are primarily driven by climatic change, but are modified by internal ecosystem processes. These changes are comparable in magnitude and rapidity to those predicted for the near future. Species at their distributional limits are particularly sensitive to climate change and contractions of range can be sudden in response to extreme climatic events such as the storm of December 1999 that damaged Picea trees far more than tree species that lay within their natural range limits. Palaeoecological records provide compelling evidence for direct climate forcing of aquatic and terrestrial ecosystems but importantly also permit comparative analyses of impacts

  4. Shifting species interactions in terrestrial dryland ecosystems under altered water availability and climate change

    Science.gov (United States)

    McCluney, Kevin E.; Belnap, Jayne; Collins, Scott L.; González, Angélica L.; Hagen, Elizabeth M.; Holland, J. Nathaniel; Kotler, Burt P.; Maestre, Fernando T.; Smith, Stanley D.; Wolf, Blair O.

    2012-01-01

    Species interactions play key roles in linking the responses of populations, communities, and ecosystems to environmental change. For instance, species interactions are an important determinant of the complexity of changes in trophic biomass with variation in resources. Water resources are a major driver of terrestrial ecology and climate change is expected to greatly alter the distribution of this critical resource. While previous studies have documented strong effects of global environmental change on species interactions in general, responses can vary from region to region. Dryland ecosystems occupy more than one-third of the Earth's land mass, are greatly affected by changes in water availability, and are predicted to be hotspots of climate change. Thus, it is imperative to understand the effects of environmental change on these globally significant ecosystems. Here, we review studies of the responses of population-level plant-plant, plant-herbivore, and predator-prey interactions to changes in water availability in dryland environments in order to develop new hypotheses and predictions to guide future research. To help explain patterns of interaction outcomes, we developed a conceptual model that views interaction outcomes as shifting between (1) competition and facilitation (plant-plant), (2) herbivory, neutralism, or mutualism (plant-herbivore), or (3) neutralism and predation (predator-prey), as water availability crosses physiological, behavioural, or population-density thresholds. We link our conceptual model to hypothetical scenarios of current and future water availability to make testable predictions about the influence of changes in water availability on species interactions. We also examine potential implications of our conceptual model for the relative importance of top-down effects and the linearity of patterns of change in trophic biomass with changes in water availability. Finally, we highlight key research needs and some possible broader impacts

  5. Using the CARDAMOM framework to retrieve global terrestrial ecosystem functioning properties

    Science.gov (United States)

    Exbrayat, Jean-François; Bloom, A. Anthony; Smallman, T. Luke; van der Velde, Ivar R.; Feng, Liang; Williams, Mathew

    2016-04-01

    Terrestrial ecosystems act as a sink for anthropogenic emissions of fossil-fuel and thereby partially offset the ongoing global warming. However, recent model benchmarking and intercomparison studies have highlighted the non-trivial uncertainties that exist in our understanding of key ecosystem properties like plant carbon allocation and residence times. It leads to worrisome differences in terrestrial carbon stocks simulated by Earth system models, and their evolution in a warming future. In this presentation we attempt to provide global insights on these properties by merging an ecosystem model with remotely-sensed global observations of leaf area and biomass through a data-assimilation system: the CARbon Data MOdel fraMework (CARDAMOM). CARDAMOM relies on a Markov Chain Monte Carlo algorithm to retrieve confidence intervals of model parameters that regulate ecosystem properties independently of any prior land-cover information. The MCMC method thereby enables an explicit representation of the uncertainty in land-atmosphere fluxes and the evolution of terrestrial carbon stocks through time. Global experiments are performed for the first decade of the 21st century using a 1°×1° spatial resolution. Relationships emerge globally between key ecosystem properties. For example, our analyses indicate that leaf lifespan and leaf mass per area are highly correlated. Furthermore, there exists a latitudinal gradient in allocation patterns: high latitude ecosystems allocate more carbon to photosynthetic carbon (leaves) while plants invest more carbon in their structural parts (wood and root) in the wet tropics. Overall, the spatial distribution of these ecosystem properties does not correspond to usual land-cover maps and are also partially correlated with disturbance regimes. For example, fire-prone ecosystems present statistically significant higher values of carbon use efficiency than less disturbed ecosystems experiencing similar climatic conditions. These results

  6. The terrestrial ecosystems at Forsmark and Laxemar-Simpevarp. SR-Site Biosphere

    Energy Technology Data Exchange (ETDEWEB)

    Loefgren, Anders [ed.; EcoAnalytica, Haegersten (Sweden)

    2010-12-15

    The ecosystem is in most cases the link between radionuclides released from a repository and the exposure of humans and other biota to them. This report describes the terrestrial ecosystems in the Forsmark and Laxemar-Simpevarp areas by summarizing and performing cross-disciplinary analyses of data from a large number of reports produced during the site investigations, Figure 1-2. The report describes the terrestrial landscape, divided here into the three main categories: forests, wetlands and agriculture land, by identifying properties that are important for element accumulation and transport

  7. Deep Atomic Binding (DAB) Approach in Interpretation of Fission Products Behavior in Terrestrial and Water Ecosystems

    International Nuclear Information System (INIS)

    Ajlouni, Abdul-Wali M.S.

    2006-01-01

    A large number of studies and models were established to explain the fission products (FP) behavior within terrestrial and water ecosystems, but a number of behaviors were non understandable, which always attributed to unknown reasons. According to DAB hypothesis, almost all fission products behaviors in terrestrial and water ecosystems could be interpreted in a wide coincidence. The gab between former models predictions, and field behavior of fission products after accidents like Chernobyl have been explained. DAB represents a tool to reduce radio-phobia as well as radiation protection expenses. (author)

  8. The terrestrial ecosystems at Forsmark and Laxemar-Simpevarp. SR-Site Biosphere

    International Nuclear Information System (INIS)

    Loefgren, Anders

    2010-12-01

    The ecosystem is in most cases the link between radionuclides released from a repository and the exposure of humans and other biota to them. This report describes the terrestrial ecosystems in the Forsmark and Laxemar-Simpevarp areas by summarizing and performing cross-disciplinary analyses of data from a large number of reports produced during the site investigations, Figure 1-2. The report describes the terrestrial landscape, divided here into the three main categories: forests, wetlands and agriculture land, by identifying properties that are important for element accumulation and transport

  9. Divergent apparent temperature sensitivity of terrestrial ecosystem respiration

    Czech Academy of Sciences Publication Activity Database

    Song, B.; Niu, S.; Luo, R.; Chen, J.; Yu, G.; Olejnik, Janusz; Wohlfahrt, G.; Kiely, G.; Noormels, A.; Montagnani, L.; Cescatti, A.; Magliulo, V.; Law, B. E.; Lund, M.; Varlagin, A.; Raschi, A.; Peichl, M.; Nilsson, M.; Merbold, L.

    2014-01-01

    Roč. 7, č. 5 (2014), s. 419-428 ISSN 1752-9921 Institutional support: RVO:67179843 Keywords : activation energy * ecosystem respiration * index of water availability * gross primary productivity Subject RIV: EH - Ecology, Behaviour Impact factor: 2.646, year: 2014

  10. Endogenous circadian regulation of carbon dioxide exchange in terrestrial ecosystems

    Science.gov (United States)

    Victor Resco de Dios; Michael L. Goulden; Kiona Ogle; Andrew D. Richardson; David Y. Hollinger; Eric A. Davidson; Josu G. Alday; Greg A. Barron-Gafford; Arnaud Carrara; Andrew S. Kowalski; Walt C. Oechel; Borja R. Reverter; Russell L. Scott; Ruth K. Varner; Ruben Diaz-Sierra; Jose M. Moreno

    2012-01-01

    It is often assumed that daytime patterns of ecosystem carbon assimilation are mostly driven by direct physiological responses to exogenous environmental cues. Under limited environmental variability, little variation in carbon assimilation should thus be expected unless endogenous plant controls on carbon assimilation, which regulate photosynthesis in time, are active...

  11. [Effects and mechanism of freeze-thawing cycles on key processes of nitrogen cycle in terrestrial ecosystem].

    Science.gov (United States)

    Wang, Li-qin; Qi, Yu-chun; Dong, Yun-she; Peng, Qin; Guo, Shu-fang; He, Yun-long; Yan, Zhong-qing

    2015-11-01

    As a widespread natural phenomenon in the soil of middle and high latitude as well as high altitude, freeze-thawing cycles have a great influence on the nitrogen cycle of terrestrial ecosystem in non-growing season. Freeze-thawing cycles can alter the physicochemical and biological properties of the soil, which thereby affect the migration and transformation of soil nitrogen. The impacts of freeze-thawing cycles on key processes of nitrogen cycle in terrestrial ecosystem found in available studies remain inconsistent, the mechanism is still not clear, and the research methods also need to be further explored and innovated. So it is necessary to sum up and analyze the existing achievements in order to better understand the processes of soil nitrogen cycle subjected to freeze-thawing cycles. This paper reviewed the research progress in China and abroad about the effects and mechanisms of freeze-thawing cycles on key processes of nitrogen cycle in terrestrial ecosystem, including mineralization, immobilization, nitrification and denitrification, N leakage and gaseous loss, and analyzed the deficiencies of extant research. The possible key research topics that should be urgently paid more attention to in the future were also discussed.

  12. Do global change experiments overestimate impacts on terrestrial ecosystems?

    DEFF Research Database (Denmark)

    Leuzinger, Sebastian; Luo, Yiqi; Beier, Claus

    2011-01-01

    In recent decades, many climate manipulation experiments have investigated biosphere responses to global change. These experiments typically examined effects of elevated atmospheric CO2, warming or drought (driver variables) on ecosystem processes such as the carbon and water cycle (response...... of the responses to decline with higher-order interactions, longer time periods and larger spatial scales. This means that on average, both positive and negative global change impacts on the biosphere might be dampened more than previously assumed....

  13. Effects of fluorine on crops, soil exoenzyme activities, and earthworms in terrestrial ecosystems.

    Science.gov (United States)

    Chae, Yooeun; Kim, Dokyung; An, Youn-Joo

    2018-04-30

    Fluorine can flow into the environment after leakage or spill accidents and these excessive amounts can cause adverse effects on terrestrial ecosystems. Using three media (filter paper, soil, and filter-paper-on-soil), we investigated the toxic effects of fluorine on the germination and growth of crops (barley, mung bean, sorghum, and wheat), on the activities of soil exoenzymes (acid phosphatase, arylsulfatase, fluorescein diacetate hydrolase, and urease) and on the survival, abnormality, and cytotoxicity of Eisenia andrei earthworms. The germination and growth of crops were affected by fluorine as exposure concentration increased. The activities of the four enzymes after 0-, 3-, 10-, and 20-day periods varied as exposure concentration increased. According to in vivo and in vitro earthworm assays, E. andrei mortality, abnormality, and cytotoxicity increased with increasing fluorine concentration. Overall, fluorine significantly affected each tested species in the concentration ranges used in this study. The activities of soil exoenzymes were also affected by soil fluorine concentration, although in an inconsistent manner. Albeit the abnormally high concentrations of fluorine in soil compared to that observed under natural conditions, its toxicity was much restrained possibly due to the adsorption of fluorine on soil particles and its combination with soil cations. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. [Assessment of shallow groundwater nitrate concentrations in typical terrestrial ecosystems of Chinese Ecosystem Research Network (CERN) during 2004-2009].

    Science.gov (United States)

    Xu, Zhi-Wei; Zhang, Xin-Yu; Sun, Xiao-Min; Yuan, Guo-Fu; Wang, Sheng-Zhong; Liu, Wen-Hua

    2011-10-01

    The nitrate-N (NO3(-) -N) concentrations of 38 shallow groundwater wells from 31 of the typical terrestrial ecosystems on Chinese Ecosystem Research Network (CERN) were assessed using the monitoring data from 2004 to 2009. The results showed that the average values of NO3(-) -N concentrations were significantly higher in the agricultural (4.85 mg x L(-1) +/- 0.42 mg x L(-1)), desert (oasis) (3.72 mg x L(-1) +/- 0.42 mg x L(-1)) and urban ecosystems (3.77 mg x L(-1) 0.51 mg x L(-1)) than in the grass (1.59 mg x L(-1) +/- 0.35 mg L(-1)) and forest ecosystems (0.39 mg x L(-1) +/- 0.03 mg x L(-1)). Nitrate was the major form of nitrogen, with between 56% to 88% of nitrogen in the nitrate-N form in the shallow groundwater of desert (oasis), urban and agricultural ecosystems. Nitrate-N concentrations for some agricultural ecosystems (Ansai, Yanting, Yucheng) and desert (oasis) ecosystems (Cele, Linze, Akesu) analysis exceeded the 10 mg x L(-1) World Health Organization drinking water standards between 14.3% and 84.6%. Significant seasonality was found in Ansai, Fengqiu, Yanting agricultural ecosystems and the Beijing urban ecosystem using the relatively high frequency monitoring data, with the higher nitrate concentrations usually found during summer and winter months. The monitoring results indicated that the shallow groundwater of agricultural ecosystems was contaminated by agricultural management practices, i.e. fertilization, while the shallow groundwater of forest ecosystems was under natural condition with no contamination from human activities.

  15. Carbon Sequestration in Terrestrial Ecosystems: A Status Report on R and D Progress

    International Nuclear Information System (INIS)

    Jacobs, G.K.

    2001-01-01

    Sequestration of carbon in terrestrial ecosystems is a low-cost option that may be available in the near-term to mitigate increasing atmospheric CO(sub 2) concentrations, while providing additional benefits. Storing carbon in terrestrial ecosystems can be achieved through maintenance of standing aboveground biomass, utilization of aboveground biomass in long-lived products, or protection of carbon (organic and inorganic) compounds present in soils. There are potential co-benefits from efforts to sequester carbon in terrestrial ecosystems. For example, long-lived valuable products (wood) are produced, erosion would be reduced, soil productivity could be improved through increased capacity to retain water and nutrients, and marginal lands could be improved and riparian ecosystems restored. Another unique feature of the terrestrial sequestration option is that it is the only option that is ''reversible'' should it become desirable or permissible. For example, forests that are created are thus investments which could be harvested should CO(sub 2) emissions be reduced in other ways to acceptable levels 50-100 years from now

  16. Effects of nitrogen deposition on carbon cycle in terrestrial ecosystems of China

    DEFF Research Database (Denmark)

    Chen, Hao; Li, Dejun; Gurmesa, Geshere Abdisa

    2015-01-01

    Nitrogen (N) deposition in China has increased greatly, but the general impact of elevated N deposition on carbon (C) dynamics in Chinese terrestrial ecosystems is not well documented. In this study we used a meta-analysis method to compile 88 studies on the effects of N deposition C cycling...... and rate of N addition. Overall, our findings suggest that 1) decreased below-ground plant C pool may limit long-term soil C sequestration; and 2) it is better to treat N-rich and N-limited ecosystems differently in modeling effects of N deposition on ecosystem C cycle....

  17. Hyperspectral Remote Sensing of Terrestrial Ecosystem Productivity from ISS

    Science.gov (United States)

    Huemmrich, K. F.; Campbell, P. K. E.; Gao, B. C.; Flanagan, L. B.; Goulden, M.

    2017-12-01

    Data from the Hyperspectral Imager for Coastal Ocean (HICO), mounted on the International Space Station (ISS), were used to develop and test algorithms for remotely retrieving ecosystem productivity. The ISS orbit introduces both limitations and opportunities for observing ecosystem dynamics. Twenty six HICO images were used from four study sites representing different vegetation types: grasslands, shrubland, and forest. Gross ecosystem production (GEP) data from eddy covariance were matched with HICO-derived spectra. Multiple algorithms were successful relating spectral reflectance with GEP, including: Spectral Vegetation Indices (SVI), SVI in a light use efficiency model framework, spectral shape characteristics through spectral derivatives and absorption feature analysis, and statistical models leading to Multiband Hyperspectral Indices (MHI) from stepwise regressions and Partial Least Squares Regression (PLSR). Algorithms were able to achieve r2 better than 0.7 for both GEP at the overpass time and daily GEP. These algorithms were successful using a diverse set of observations combining data from multiple years, multiple times during growing season, different times of day, with different view angles, and different vegetation types. The demonstrated robustness of the algorithms presented in this study over these conditions provides some confidence in mapping spatial patterns of GEP, describing variability within fields as well as the regional patterns based only on spectral reflectance information. The ISS orbit provides periods with multiple observations collected at different times of the day within a period of a few days. Diurnal GEP patterns were estimated comparing the half-hourly average GEP from the flux tower against HICO estimates of GEP (r2=0.87) if morning, midday, and afternoon observations were available for average fluxes in the time period.

  18. Past Changes in Arctic Terrestrial Ecosystems, Climate and UV Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Callaghan, Terry V. [Abisko Scientific Research Station, Abisko (Sweden); Bjoern, Lars Olof [Lund Univ. (Sweden). Dept. of Cell and Organism Biology; Chernov, Yuri [Russian Academy of Sciences, Moscow (Russian Federation). A.N. Severtsov Inst. of Evolutionary Morphology and Animal Ecology] (and others)

    2004-11-01

    At the last glacial maximum, vast ice sheets covered many continental areas. The beds of some shallow seas were exposed thereby connecting previously separated landmasses. Although some areas were ice-free and supported a flora and fauna, mean annual temperatures were 10-13 deg C colder than during the Holocene. Within a few millennia of the glacial maximum, deglaciation started, characterized by a series of climatic fluctuations between about 18,000 and 11,400 years ago. Following the general thermal maximum in the Holocene, there has been a modest overall cooling trend, superimposed upon which have been a series of millennial and centennial fluctuations in climate such as the 'Little Ice Age' spanning approximately the late 13th to early 19th centuries. Throughout the climatic fluctuations of the last 150,000 years, Arctic ecosystems and biota have been close to their minimum extent within the most recent 10,000 years. They suffered loss of diversity as a result of extinctions during the most recent large-magnitude rapid global warming at the end of the last glacial stage. Consequently, Arctic ecosystems and biota such as large vertebrates are already under pressure and are particularly vulnerable to current and projected future global warming. Evidence from the past indicates that the treeline will very probably advance, perhaps rapidly, into tundra areas, as it did during the early Holocene, reducing the extent of tundra and increasing the risk of species extinction. Species will very probably extend their ranges northwards, displacing Arctic species as in the past. However, unlike the early Holocene, when lower relative sea level allowed a belt of tundra to persist around at least some parts of the Arctic basin when treelines advanced to the present coast, sea level is very likely to rise in future, further restricting the area of tundra and other treeless Arctic ecosystems. The negative response of current Arctic ecosystems to global climatic

  19. Effects of nitrogen deposition on carbon cycle in terrestrial ecosystems of China: A meta-analysis

    International Nuclear Information System (INIS)

    Chen, Hao; Li, Dejun; Gurmesa, Geshere A.; Yu, Guirui; Li, Linghao; Zhang, Wei; Fang, Huajun; Mo, Jiangming

    2015-01-01

    Nitrogen (N) deposition in China has increased greatly, but the general impact of elevated N deposition on carbon (C) dynamics in Chinese terrestrial ecosystems is not well documented. In this study we used a meta-analysis method to compile 88 studies on the effects of N deposition C cycling on Chinese terrestrial ecosystems. Our results showed that N addition did not change soil C pools but increased above-ground plant C pool. A large decrease in below-ground plant C pool was observed. Our result also showed that the impacts of N addition on ecosystem C dynamics depend on ecosystem type and rate of N addition. Overall, our findings suggest that 1) decreased below-ground plant C pool may limit long-term soil C sequestration; and 2) it is better to treat N-rich and N-limited ecosystems differently in modeling effects of N deposition on ecosystem C cycle. - Highlights: • Meta-analysis was used to address the effects of N addition on C cycle. • N addition caused an large decease in belowground plant C pool. • N-rich and N-limited ecosystems had different responses to N addition. - N addition caused a large decrease in below-ground plant C pool.

  20. Impacts of Environmental Nanoparticles on Chemical, Biological and Hydrological Processes in Terrestrial Ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Qafoku, Nikolla

    2012-01-01

    This chapter provides insights on nanoparticle (NP) influence or control on the extent and timescales of single or coupled physical, chemical, biological and hydrological reactions and processes that occur in terrestrial ecosystems. Examples taken from the literature that show how terrestrial NPs may determine the fate of the aqueous and sorbed (adsorbed or precipitated) chemical species of nutrients and contaminants, are also included in this chapter. Specifically, in the first section, chapter objectives, term definitions and discussions on size-dependent properties, the origin and occurrence of NP in terrestrial ecosystems and NP toxicity, are included. In the second section, the topic of the binary interactions of NPs of different sizes, shapes, concentrations and ages with the soil solution chemical species is covered, focusing on NP formation, stability, aggregation, ability to serve as sorbents, or surface-mediated precipitation catalysts, or electron donors and acceptors. In the third section, aspects of the interactions in the ternary systems composed of environmental NP, nutrient/contaminant chemical species, and the soil/sediment matrix are discussed, focusing on the inhibitory and catalytic effects of environmental NP on nutrient/contaminant advective mobility and mass transfer, adsorption and desorption, dissolution and precipitation and redox reactions that occur in terrestrial ecosystems. These three review sections are followed by a short summary of future research needs and directions, the acknowledgements, the list of the references, and the figures.

  1. Stimulation of terrestrial ecosystem carbon storage by nitrogen addition: a meta-analysis.

    Science.gov (United States)

    Yue, Kai; Peng, Yan; Peng, Changhui; Yang, Wanqin; Peng, Xin; Wu, Fuzhong

    2016-01-27

    Elevated nitrogen (N) deposition alters the terrestrial carbon (C) cycle, which is likely to feed back to further climate change. However, how the overall terrestrial ecosystem C pools and fluxes respond to N addition remains unclear. By synthesizing data from multiple terrestrial ecosystems, we quantified the response of C pools and fluxes to experimental N addition using a comprehensive meta-analysis method. Our results showed that N addition significantly stimulated soil total C storage by 5.82% ([2.47%, 9.27%], 95% CI, the same below) and increased the C contents of the above- and below-ground parts of plants by 25.65% [11.07%, 42.12%] and 15.93% [6.80%, 25.85%], respectively. Furthermore, N addition significantly increased aboveground net primary production by 52.38% [40.58%, 65.19%] and litterfall by 14.67% [9.24%, 20.38%] at a global scale. However, the C influx from the plant litter to the soil through litter decomposition and the efflux from the soil due to microbial respiration and soil respiration showed insignificant responses to N addition. Overall, our meta-analysis suggested that N addition will increase soil C storage and plant C in both above- and below-ground parts, indicating that terrestrial ecosystems might act to strengthen as a C sink under increasing N deposition.

  2. Microbial ecology of Thailand tsunami and non-tsunami affected terrestrials.

    Science.gov (United States)

    Somboonna, Naraporn; Wilantho, Alisa; Jankaew, Kruawun; Assawamakin, Anunchai; Sangsrakru, Duangjai; Tangphatsornruang, Sithichoke; Tongsima, Sissades

    2014-01-01

    The effects of tsunamis on microbial ecologies have been ill-defined, especially in Phang Nga province, Thailand. This ecosystem was catastrophically impacted by the 2004 Indian Ocean tsunami as well as the 600 year-old tsunami in Phra Thong island, Phang Nga province. No study has been conducted to elucidate their effects on microbial ecology. This study represents the first to elucidate their effects on microbial ecology. We utilized metagenomics with 16S and 18S rDNA-barcoded pyrosequencing to obtain prokaryotic and eukaryotic profiles for this terrestrial site, tsunami affected (S1), as well as a parallel unaffected terrestrial site, non-tsunami affected (S2). S1 demonstrated unique microbial community patterns than S2. The dendrogram constructed using the prokaryotic profiles supported the unique S1 microbial communities. S1 contained more proportions of archaea and bacteria domains, specifically species belonging to Bacteroidetes became more frequent, in replacing of the other typical floras like Proteobacteria, Acidobacteria and Basidiomycota. Pathogenic microbes, including Acinetobacter haemolyticus, Flavobacterium spp. and Photobacterium spp., were also found frequently in S1. Furthermore, different metabolic potentials highlighted this microbial community change could impact the functional ecology of the site. Moreover, the habitat prediction based on percent of species indicators for marine, brackish, freshwater and terrestrial niches pointed the S1 to largely comprise marine habitat indicating-species.

  3. Effects of nitrogen deposition on carbon cycle in terrestrial ecosystems of China: A meta-analysis.

    Science.gov (United States)

    Chen, Hao; Li, Dejun; Gurmesa, Geshere A; Yu, Guirui; Li, Linghao; Zhang, Wei; Fang, Huajun; Mo, Jiangming

    2015-11-01

    Nitrogen (N) deposition in China has increased greatly, but the general impact of elevated N deposition on carbon (C) dynamics in Chinese terrestrial ecosystems is not well documented. In this study we used a meta-analysis method to compile 88 studies on the effects of N deposition C cycling on Chinese terrestrial ecosystems. Our results showed that N addition did not change soil C pools but increased above-ground plant C pool. A large decrease in below-ground plant C pool was observed. Our result also showed that the impacts of N addition on ecosystem C dynamics depend on ecosystem type and rate of N addition. Overall, our findings suggest that 1) decreased below-ground plant C pool may limit long-term soil C sequestration; and 2) it is better to treat N-rich and N-limited ecosystems differently in modeling effects of N deposition on ecosystem C cycle. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Biodiversity of Terrestrial Ecosystems in Tropical to Temperate Australia

    Directory of Open Access Journals (Sweden)

    Raymond L. Specht

    2012-01-01

    Full Text Available During the short period of annual foliage growth in evergreen plant communities, aerodynamic fluxes (frictional, thermal, evaporative in the atmosphere as it flows over and through a plant community determine the Foliage Projective Covers and leaf attributes in overstorey and understorey strata. The number of leaves produced on each vertical foliage shoot depends on available soil water and nutrients during this growth period. The area of all leaves exposed to solar radiation determines net photosynthetic fixation of the plant community throughout the year. In turn, the species richness (number of species per hectare of both plants and resident vertebrates is determined. The species richness of unicellular algae and small multicellular isopods in permanent freshwater lagoons in Northern Australia may possibly have been increased by radiation released from nearby uranium deposits. Evolution of new angiosperms probably occurred in refugia during periods of extreme drought. When favourable climates were restored, the vegetation expanded to result in high Gamma Biodiversity (number of plant species per region but with each major plant community having essentially the same species richness (number of plant species per hectare. The probable effects of pollution and Global Warming on biodiversity in Australian ecosystems, that experience seasonal drought, are discussed.

  5. Quantifying terrestrial ecosystem carbon dynamics in the Jinsha watershed, Upper Yangtze, China from 1975 to 2000

    Science.gov (United States)

    Zhao, Shuqing; Liu, Shuguang; Yin, Runsheng; Li, Zhengpeng; Deng, Yulin; Tan, Kun; Deng, Xiangzheng; Rothstein, David; Qi, Jiaguo

    2010-01-01

    Quantifying the spatial and temporal dynamics of carbon stocks in terrestrial ecosystems and carbon fluxes between the terrestrial biosphere and the atmosphere is critical to our understanding of regional patterns of carbon budgets. Here we use the General Ensemble biogeochemical Modeling System to simulate the terrestrial ecosystem carbon dynamics in the Jinsha watershed of China’s upper Yangtze basin from 1975 to 2000, based on unique combinations of spatial and temporal dynamics of major driving forces, such as climate, soil properties, nitrogen deposition, and land use and land cover changes. Our analysis demonstrates that the Jinsha watershed ecosystems acted as a carbon sink during the period of 1975–2000, with an average rate of 0.36 Mg/ha/yr, primarily resulting from regional climate variation and local land use and land cover change. Vegetation biomass accumulation accounted for 90.6% of the sink, while soil organic carbon loss before 1992 led to a lower net gain of carbon in the watershed, and after that soils became a small sink. Ecosystem carbon sink/source patterns showed a high degree of spatial heterogeneity. Carbon sinks were associated with forest areas without disturbances, whereas carbon sources were primarily caused by stand-replacing disturbances. It is critical to adequately represent the detailed fast-changing dynamics of land use activities in regional biogeochemical models to determine the spatial and temporal evolution of regional carbon sink/source patterns.

  6. Solar radiation uncorks the lignin bottleneck on plant litter decomposition in terrestrial ecosystems

    Science.gov (United States)

    Austin, A.; Ballare, C. L.; Méndez, M. S.

    2015-12-01

    Plant litter decomposition is an essential process in the first stages of carbon and nutrient turnover in terrestrial ecosystems, and together with soil microbial biomass, provide the principal inputs of carbon for the formation of soil organic matter. Photodegradation, the photochemical mineralization of organic matter, has been recently identified as a mechanism for previously unexplained high rates of litter mass loss in low rainfall ecosystems; however, the generality of this process as a control on carbon cycling in terrestrial ecosystems is not known, and the indirect effects of photodegradation on biotic stimulation of carbon turnover have been debated in recent studies. We demonstrate that in a wide range of plant species, previous exposure to solar radiation, and visible light in particular, enhanced subsequent biotic degradation of leaf litter. Moreover, we demonstrate that the mechanism for this enhancement involves increased accessibility for microbial enzymes to plant litter carbohydrates due to a reduction in lignin content. Photodegradation of plant litter reduces the structural and chemical bottleneck imposed by lignin in secondary cell walls. In litter from woody plant species, specific interactions with ultraviolet radiation obscured facilitative effects of solar radiation on biotic decomposition. The generalized positive effect of solar radiation exposure on subsequent microbial activity is mediated by increased accessibility to cell wall polysaccharides, which suggests that photodegradation is quantitatively important in determining rates of mass loss, nutrient release and the carbon balance in a broad range of terrestrial ecosystems.

  7. Shifting species interactions in terrestrial dryland ecosystems under altered water availability and climate change.

    Science.gov (United States)

    McCluney, Kevin E; Belnap, Jayne; Collins, Scott L; González, Angélica L; Hagen, Elizabeth M; Nathaniel Holland, J; Kotler, Burt P; Maestre, Fernando T; Smith, Stanley D; Wolf, Blair O

    2012-08-01

    Species interactions play key roles in linking the responses of populations, communities, and ecosystems to environmental change. For instance, species interactions are an important determinant of the complexity of changes in trophic biomass with variation in resources. Water resources are a major driver of terrestrial ecology and climate change is expected to greatly alter the distribution of this critical resource. While previous studies have documented strong effects of global environmental change on species interactions in general, responses can vary from region to region. Dryland ecosystems occupy more than one-third of the Earth's land mass, are greatly affected by changes in water availability, and are predicted to be hotspots of climate change. Thus, it is imperative to understand the effects of environmental change on these globally significant ecosystems. Here, we review studies of the responses of population-level plant-plant, plant-herbivore, and predator-prey interactions to changes in water availability in dryland environments in order to develop new hypotheses and predictions to guide future research. To help explain patterns of interaction outcomes, we developed a conceptual model that views interaction outcomes as shifting between (1) competition and facilitation (plant-plant), (2) herbivory, neutralism, or mutualism (plant-herbivore), or (3) neutralism and predation (predator-prey), as water availability crosses physiological, behavioural, or population-density thresholds. We link our conceptual model to hypothetical scenarios of current and future water availability to make testable predictions about the influence of changes in water availability on species interactions. We also examine potential implications of our conceptual model for the relative importance of top-down effects and the linearity of patterns of change in trophic biomass with changes in water availability. Finally, we highlight key research needs and some possible broader impacts

  8. Lateral diffusion of nutrients by mammalian herbivores in terrestrial ecosystems.

    Directory of Open Access Journals (Sweden)

    Adam Wolf

    Full Text Available Animals translocate nutrients by consuming nutrients at one point and excreting them or dying at another location. Such lateral fluxes may be an important mechanism of nutrient supply in many ecosystems, but lack quantification and a systematic theoretical framework for their evaluation. This paper presents a mathematical framework for quantifying such fluxes in the context of mammalian herbivores. We develop an expression for lateral diffusion of a nutrient, where the diffusivity is a biologically determined parameter depending on the characteristics of mammals occupying the domain, including size-dependent phenomena such as day range, metabolic demand, food passage time, and population size. Three findings stand out: (a Scaling law-derived estimates of diffusion parameters are comparable to estimates calculated from estimates of each coefficient gathered from primary literature. (b The diffusion term due to transport of nutrients in dung is orders of magnitude large than the coefficient representing nutrients in bodymass. (c The scaling coefficients show that large herbivores make a disproportionate contribution to lateral nutrient transfer. We apply the diffusion equation to a case study of Kruger National Park to estimate the conditions under which mammal-driven nutrient transport is comparable in magnitude to other (abiotic nutrient fluxes (inputs and losses. Finally, a global analysis of mammalian herbivore transport is presented, using a comprehensive database of contemporary animal distributions. We show that continents vary greatly in terms of the importance of animal-driven nutrient fluxes, and also that perturbations to nutrient cycles are potentially quite large if threatened large herbivores are driven to extinction.

  9. Byers Peninsula: A reference site for coastal, terrestrial and limnetic ecosystem studies in maritime Antarctica

    Science.gov (United States)

    Quesada, A.; Camacho, A.; Rochera, C.; Velázquez, D.

    2009-11-01

    This article describes the development of an international and multidisciplinary project funded by the Spanish Polar Programme on Byers Peninsula (Livingston Island, South Shetlands). The project adopted Byers Peninsula as an international reference site for coastal and terrestrial (including inland waters) research within the framework of the International Polar Year initiative. Over 30 scientists from 12 countries and 26 institutions participated in the field work, and many others participated in the processing of the samples. The main themes investigated were: Holocene changes in climate, using both lacustrine sediment cores and palaeo-nests of penguins; limnology of the lakes, ponds, rivers and wetlands; microbiology of microbial mats, ecology of microbial food webs and viral effects on aquatic ecosystems; ornithology, with investigations on a Gentoo penguin rookery ( Pygoscelis papua) as well as the flying ornithofauna; biocomplexity and life cycles of species from different taxonomic groups; analysis of a complete watershed unit from a landscape perspective; and human impacts, specifically the effect of trampling on soil characteristics and biota. Byers Peninsula offers many features as an international reference site given it is one of the largest ice-free areas in the Antarctic Peninsula region, it has a variety of different landscape units, and it hosts diverse aquatic ecosystems. Moreover, the Byers Peninsula is a hotspot for Antarctic biodiversity, and because of its high level of environmental protection, it has been very little affected by human activities. Finally, the proximity to the Spanish polar installations on Livingston Island and the experience derived from previous expeditions to the site make it logistically feasible as a site for ongoing monitoring and research.

  10. Modeling Carbon Turnover in Five Terrestrial Ecosystems in the Boreal Zone Using Multiple Criteria of Acceptance

    International Nuclear Information System (INIS)

    Karlberg, Louise; Gustafsson, David; Jansson, Per-Erik

    2006-01-01

    Estimates of carbon fluxes and turnover in ecosystems are key elements in the understanding of climate change and in predicting the accumulation of trace elements in the biosphere. In this paper we present estimates of carbon fluxes and turnover times for five terrestrial ecosystems using a modeling approach. Multiple criteria of acceptance were used to parameterize the model, thus incorporating large amounts of multi-faceted empirical data in the simulations in a standardized manner. Mean turnover times of carbon were found to be rather similar between systems with a few exceptions, even though the size of both the pools and the fluxes varied substantially. Depending on the route of the carbon through the ecosystem, turnover times varied from less than one year to more than one hundred, which may be of importance when considering trace element transport and retention. The parameterization method was useful both in the estimation of unknown parameters, and to identify variability in carbon turnover in the selected ecosystems

  11. Conversion of native terrestrial ecosystems in Hawai‘i to novel grazing systems: a review

    Science.gov (United States)

    Leopold, Christina R.; Hess, Steven C.

    2017-01-01

    The remote oceanic islands of Hawai‘i exemplify the transformative effects that non-native herbivorous mammals can bring to isolated terrestrial ecosystems. We reviewed published literature containing systematically collected, analyzed, and peer-reviewed original data specifically addressing direct effects of non-native hoofed mammals (ungulates) on terrestrial ecosystems, and indirect effects and interactions on ecosystem processes in Hawai‘i. The effects of ungulates on native vegetation and ecosystems were addressed in 58 original studies and mostly showed strong short-term regeneration of dominant native trees and understory ferns after ungulate removal, but unassisted recovery was dependent on the extent of previous degradation. Ungulates were associated with herbivory, bark-stripping, disturbance by hoof action, soil erosion, enhanced nutrient cycling from the interaction of herbivory and grasses, and increased pyrogenicity and competition between native plants and pasture grasses. No studies demonstrated that ungulates benefitted native ecosystems except in short-term fire-risk reduction. However, non-native plants became problematic and continued to proliferate after release from herbivory, including at least 11 species of non-native pasture grasses that had become established prior to ungulate removal. Competition from non-native grasses inhibited native species regeneration where degradation was extensive. These processes have created novel grazing systems which, in some cases, have irreversibly altered Hawaii’s terrestrial ecology. Non-native plant control and outplanting of rarer native species will be necessary for recovery where degradation has been extensive. Lack of unassisted recovery in some locations should not be construed as a reason to not attempt restoration of other ecosystems.

  12. The terrestrial ecosystems at Forsmark and Laxemar-Simpevarp. Site descriptive modelling SDM site

    Energy Technology Data Exchange (ETDEWEB)

    Loefgren, Anders [EcoAnalytica, Haegersten (Sweden); ed.

    2008-12-15

    This report describes the terrestrial ecosystems in the Forsmark and Laxemar-Simpevarp areas by summarizing ecological data and data from disciplines such as hydrology, quaternary geology and chemistry. The description therefore includes a number of different processes that drive element fluxes in the ecosystems, such as net primary production, heterotrophic respiration, transpiration, and horizontal transport from land to streams and lakes. Moreover, the human appropriation of the landscape is described with regard to land use and potential and actual utilization of food resources both today and in a historical perspective

  13. The fate of mercury in Arctic terrestrial and aquatic ecosystems, a review

    DEFF Research Database (Denmark)

    Douglas, Thomas A.; Loseto, Lisa L.; MacDonald, Robie W.

    2012-01-01

    the fate of Hg in most ecosystems, and the role of trophic processes in controlling Hg in higher order animals are also included. Case studies on Eastern Beaufort Sea beluga (Delphinapterus leucas) and landlocked Arctic char (Salvelinus alpinus) are presented as examples of the relationship between...... into non-biological archives is also addressed. The review concludes by identifying major knowledge gaps in our understanding, including: (1) the rates of Hg entry into marine and terrestrial ecosystems and the rates of inorganic and MeHg uptake by Arctic microbial and algal communities; (2...

  14. The terrestrial ecosystems at Forsmark and Laxemar-Simpevarp. Site descriptive modelling SDM site

    International Nuclear Information System (INIS)

    Loefgren, Anders

    2008-12-01

    This report describes the terrestrial ecosystems in the Forsmark and Laxemar-Simpevarp areas by summarizing ecological data and data from disciplines such as hydrology, quaternary geology and chemistry. The description therefore includes a number of different processes that drive element fluxes in the ecosystems, such as net primary production, heterotrophic respiration, transpiration, and horizontal transport from land to streams and lakes. Moreover, the human appropriation of the landscape is described with regard to land use and potential and actual utilization of food resources both today and in a historical perspective

  15. Potential Applications of Gosat Based Carbon Budget Products to Refine Terrestrial Ecosystem Model

    Science.gov (United States)

    Kondo, M.; Ichii, K.

    2011-12-01

    Estimation of carbon exchange in terrestrial ecosystem associates with difficulties due to complex entanglement of physical and biological processes: thus, the net ecosystem productivity (NEP) estimated from simulation often differs among process-based terrestrial ecosystem models. In addition to complexity of the system, validation can only be conducted in a point scale since reliable observation is only available from ground observations. With a lack of large spatial data, extension of model simulation to a global scale results in significant uncertainty in the future carbon balance and climate change. Greenhouse gases Observing SATellite (GOSAT), launched by the Japanese space agency (JAXA) in January, 2009, is the 1st operational satellite promised to deliver the net land-atmosphere carbon budget to the terrestrial biosphere research community. Using that information, the model reproducibility of carbon budget is expected to improve: hence, gives a better estimation of the future climate change. This initial analysis is to seek and evaluate the potential applications of GOSAT observation toward the sophistication of terrestrial ecosystem model. The present study was conducted in two processes: site-based analysis using eddy covariance observation data to assess the potential use of terrestrial carbon fluxes (GPP, RE, and NEP) to refine the model, and extension of the point scale analysis to spatial using Carbon Tracker product as a prototype of GOSAT product. In the first phase of the experiment, it was verified that an optimization routine adapted to a terrestrial model, Biome-BGC, yielded the improved result with respect to eddy covariance observation data from AsiaFlux Network. Spatial data sets used in the second phase were consists of GPP from empirical algorithm (e.g. support vector machine), NEP from Carbon Tracker, and RE from the combination of these. These spatial carbon flux estimations was used to refine the model applying the exactly same

  16. [Roles of soil dissolved organic carbon in carbon cycling of terrestrial ecosystems: a review].

    Science.gov (United States)

    Li, Ling; Qiu, Shao-Jun; Liu, Jing-Tao; Liu, Qing; Lu, Zhao-Hua

    2012-05-01

    Soil dissolved organic carbon (DOC) is an active fraction of soil organic carbon pool, playing an important role in the carbon cycling of terrestrial ecosystems. In view of the importance of the carbon cycling, this paper summarized the roles of soil DOC in the soil carbon sequestration and greenhouse gases emission, and in considering of our present ecological and environmental problems such as soil acidification and climate warming, discussed the effects of soil properties, environmental factors, and human activities on the soil DOC as well as the response mechanisms of the DOC. This review could be helpful to the further understanding of the importance of soil DOC in the carbon cycling of terrestrial ecosystems and the reduction of greenhouse gases emission.

  17. Temporary streams in temperate zones: recognizing, monitoring and restoring transitional aquatic-terrestrial ecosystems

    OpenAIRE

    Stubbington, Rachel; England, Judy; Wood, Paul J.; Sefton, Catherine E.M.

    2017-01-01

    Temporary streams are defined by periodic flow cessation, and may experience partial or complete loss of surface water. The ecology and hydrology of these transitional aquatic-terrestrial ecosystems have received unprecedented attention in recent years. Research has focussed on the arid, semi-arid, and Mediterranean regions in which temporary systems are the dominant stream type, and those in cooler, wetter temperate regions with an oceanic climate influence are also receiving increasing atte...

  18. Linkages Among Water Vapor Flows, Food Production, and Terrestrial Ecosystem Services

    Directory of Open Access Journals (Sweden)

    Johan Rockström

    1999-12-01

    Full Text Available Global freshwater assessments have not addressed the linkages among water vapor flows, agricultural food production, and terrestrial ecosystem services. We perform the first bottom-up estimate of continental water vapor flows, subdivided into the major terrestrial biomes, and arrive at a total continental water vapor flow of 70,000 km3/yr (ranging from 56,000 to 84,000 km3/yr. Of this flow, 90% is attributed to forests, including woodlands (40,000 km3/yr, wetlands (1400 km3/yr, grasslands (15,100 km3/yr, and croplands (6800 km3/yr. These terrestrial biomes sustain society with essential welfare-supporting ecosystem services, including food production. By analyzing the freshwater requirements of an increasing demand for food in the year 2025, we discover a critical trade-off between flows of water vapor for food production and for other welfare-supporting ecosystem services. To reduce the risk of unintentional welfare losses, this trade-off must become embedded in intentional ecohydrological landscape management.

  19. Photodegradation alleviates the lignin bottleneck for carbon turnover in terrestrial ecosystems.

    Science.gov (United States)

    Austin, Amy T; Méndez, M Soledad; Ballaré, Carlos L

    2016-04-19

    A mechanistic understanding of the controls on carbon storage and losses is essential for our capacity to predict and mitigate human impacts on the global carbon cycle. Plant litter decomposition is an important first step for carbon and nutrient turnover, and litter inputs and losses are essential in determining soil organic matter pools and the carbon balance in terrestrial ecosystems. Photodegradation, the photochemical mineralization of organic matter, has been recently identified as a mechanism for previously unexplained high rates of litter mass loss in arid lands; however, the global significance of this process as a control on carbon cycling in terrestrial ecosystems is not known. Here we show that, across a wide range of plant species, photodegradation enhanced subsequent biotic degradation of leaf litter. Moreover, we demonstrate that the mechanism for this enhancement involves increased accessibility to plant litter carbohydrates for microbial enzymes. Photodegradation of plant litter, driven by UV radiation, and especially visible (blue-green) light, reduced the structural and chemical bottleneck imposed by lignin in secondary cell walls. In leaf litter from woody species, specific interactions with UV radiation obscured facilitative effects of solar radiation on biotic decomposition. The generalized effect of sunlight exposure on subsequent microbial activity, mediated by increased accessibility to cell wall polysaccharides, suggests that photodegradation is quantitatively important in determining rates of mass loss, nutrient release, and the carbon balance in a broad range of terrestrial ecosystems.

  20. Water Use Efficiency of China's Terrestrial Ecosystems and Responses to Drought

    Science.gov (United States)

    Liu, Y.; Xiao, J.; Ju, W.; Zhou, Y.; Wang, S.; Wu, X.

    2015-12-01

    Yibo Liu1, 2, Jingfeng Xiao2, Weimin Ju3, Yanlian Zhou4, Shaoqiang Wang5, Xiaocui Wu31 Jiangsu Key Laboratory of Agricultural Meteorology, School of Applied Meteorology, Nanjing University of Information Science and Technology, Nanjing, 210044, China, 2Earth Systems Research Center, Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, NH 03824, USA, 3 International Institute for Earth System Sciences, Nanjing University, Nanjing, 210023, China, 4 School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing, 210023, China, 5 Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China Water use efficiency (WUE) measures the trade-off between carbon gain and water loss of terrestrial ecosystems, and better understanding its dynamics and controlling factors is essential for predicting ecosystem responses to climate change. We assessed the magnitude, spatial patterns, and trends of WUE of China's terrestrial ecosystems and its responses to drought using a process-based ecosystem model. During the period from 2000 to 2011, the national average annual WUE (net primary productivity (NPP)/evapotranspiration (ET)) of China was 0.79 g C kg-1 H2O. Annual WUE decreased in the southern regions because of the decrease in NPP and increase in ET and increased in most northern regions mainly because of the increase in NPP. Droughts usually increased annual WUE in Northeast China and central Inner Mongolia but decreased annual WUE in central China. "Turning-points" were observed for southern China where moderate and extreme drought reduced annual WUE and severe drought slightly increased annual WUE. The cumulative lagged effect of drought on monthly WUE varied by region. Our findings have implications for ecosystem management and climate policy making. WUE is expected to continue to change under future climate

  1. Effects of Climate and Ecosystem Disturbances on Biogeochemical Cycling in a Semi-Natural Terrestrial Ecosystem

    International Nuclear Information System (INIS)

    Beier, Claus; Schmidt, Inger Kappel; Kristensen, Hanne Lakkenborg

    2004-01-01

    The effects of increased temperature and potential ecosystem disturbances on biogeochemical cycling were investigated by manipulation of temperature in a mixed Calluna/grass heathland in Denmark. A reflective curtain covered the vegetation during the night to reduce the heat loss of IR radiation from the ecosystem to the atmosphere. This 'night time warming' was done for 3 years and warmed the air and soil by 1.1 deg. C. Warming was combined with ecosystem disturbances, including infestation by Calluna heather beetles (Lochmaea suturalis Thompson) causing complete defoliation of Calluna leaves during the summer 2000, and subsequent harvesting of all aboveground biomass during the autumn. Small increases in mineralisation rates were induced by warming and resulted in increased leaching of nitrogen from the organic soil layer. The increased nitrogen leaching from the organic soil layer was re-immobilised in the mineral soil layer as warming stimulated plant growth and thereby increased nitrogen immobilisation. Contradictory to the generally moderate effects of warming, the heather beetle infestation had very strong effects on mineralisation rates and the plant community. The grasses completely out-competed the Calluna plants which had not re-established two years after the infestation, probably due to combined effects of increased nutrient availability and the defoliation of Calluna. On the short term, ecosystem disturbances may have very strong effects on internal ecosystem processes and plant community structure compared to the more long-term effects of climate change

  2. Assessing antiquity and turnover of terrestrial ecosystems in eastern North America using fossil pollen data: A preliminary study

    International Nuclear Information System (INIS)

    Liu Yao; Jackson, Stephen T; Brewer, Simon; Williams, John W

    2010-01-01

    We explored formal approaches to identifying and interpreting the antiquity and turnover of terrestrial ecosystems in eastern North America using pollen records. Preliminary results of cluster analyses, receiver-operating characteristic (ROC) analyses, and likelihood estimation of ecosystem analog in a simple Bayesian model allow assessment of modern ecosystem antiquities and past ecosystem turnovers. Approaches discussed in this study thus provide a vehicle for further studies.

  3. Modeled responses of terrestrial ecosystems to elevated atmospheric CO2: a comparison of simulations by the biogeochemistry models of the Vegetation/Ecosystem Modeling and Analysis Project (VEMAP).

    Science.gov (United States)

    Pan, Yude; Melillo, Jerry M; McGuire, A David; Kicklighter, David W; Pitelka, Louis F; Hibbard, Kathy; Pierce, Lars L; Running, Steven W; Ojima, Dennis S; Parton, William J; Schimel, David S

    1998-04-01

    Although there is a great deal of information concerning responses to increases in atmospheric CO 2 at the tissue and plant levels, there are substantially fewer studies that have investigated ecosystem-level responses in the context of integrated carbon, water, and nutrient cycles. Because our understanding of ecosystem responses to elevated CO 2 is incomplete, modeling is a tool that can be used to investigate the role of plant and soil interactions in the response of terrestrial ecosystems to elevated CO 2 . In this study, we analyze the responses of net primary production (NPP) to doubled CO 2 from 355 to 710 ppmv among three biogeochemistry models in the Vegetation/Ecosystem Modeling and Analysis Project (VEMAP): BIOME-BGC (BioGeochemical Cycles), Century, and the Terrestrial Ecosystem Model (TEM). For the conterminous United States, doubled atmospheric CO 2 causes NPP to increase by 5% in Century, 8% in TEM, and 11% in BIOME-BGC. Multiple regression analyses between the NPP response to doubled CO 2 and the mean annual temperature and annual precipitation of biomes or grid cells indicate that there are negative relationships between precipitation and the response of NPP to doubled CO 2 for all three models. In contrast, there are different relationships between temperature and the response of NPP to doubled CO 2 for the three models: there is a negative relationship in the responses of BIOME-BGC, no relationship in the responses of Century, and a positive relationship in the responses of TEM. In BIOME-BGC, the NPP response to doubled CO 2 is controlled by the change in transpiration associated with reduced leaf conductance to water vapor. This change affects soil water, then leaf area development and, finally, NPP. In Century, the response of NPP to doubled CO 2 is controlled by changes in decomposition rates associated with increased soil moisture that results from reduced evapotranspiration. This change affects nitrogen availability for plants, which

  4. Simultaneous reproduction of global carbon exchange and storage of terrestrial forest ecosystems

    Science.gov (United States)

    Kondo, M.; Ichii, K.

    2012-12-01

    Understanding the mechanism of the terrestrial carbon cycle is essential for assessing the impact of climate change. Quantification of both carbon exchange and storage is the key to the understanding, but it often associates with difficulties due to complex entanglement of environmental and physiological factors. Terrestrial ecosystem models have been the major tools to assess the terrestrial carbon budget for decades. Because of its strong association with climate change, carbon exchange has been more rigorously investigated by the terrestrial biosphere modeling community. Seeming success of model based assessment of carbon budge often accompanies with the ill effect, substantial misrepresentation of storage. In practice, a number of model based analyses have paid attention solely on terrestrial carbon fluxes and often neglected carbon storage such as forest biomass. Thus, resulting model parameters are inevitably oriented to carbon fluxes. This approach is insufficient to fully reduce uncertainties about future terrestrial carbon cycles and climate change because it does not take into account the role of biomass, which is equivalently important as carbon fluxes in the system of carbon cycle. To overcome this issue, a robust methodology for improving the global assessment of both carbon budget and storage is needed. One potentially effective approach to identify a suitable balance of carbon allocation proportions for each individual ecosystem. Carbon allocations can influence the plant growth by controlling the amount of investment acquired from photosynthesis, as well as carbon fluxes by controlling the carbon content of leaves and litter, both are active media for photosynthesis and decomposition. Considering those aspects, there may exist the suitable balance of allocation proportions enabling the simultaneous reproduction of carbon budget and storage. The present study explored the existence of such suitable balances of allocation proportions, and examines the

  5. Bayesian calibration of terrestrial ecosystem models: a study of advanced Markov chain Monte Carlo methods

    Science.gov (United States)

    Lu, Dan; Ricciuto, Daniel; Walker, Anthony; Safta, Cosmin; Munger, William

    2017-09-01

    Calibration of terrestrial ecosystem models is important but challenging. Bayesian inference implemented by Markov chain Monte Carlo (MCMC) sampling provides a comprehensive framework to estimate model parameters and associated uncertainties using their posterior distributions. The effectiveness and efficiency of the method strongly depend on the MCMC algorithm used. In this work, a differential evolution adaptive Metropolis (DREAM) algorithm is used to estimate posterior distributions of 21 parameters for the data assimilation linked ecosystem carbon (DALEC) model using 14 years of daily net ecosystem exchange data collected at the Harvard Forest Environmental Measurement Site eddy-flux tower. The calibration of DREAM results in a better model fit and predictive performance compared to the popular adaptive Metropolis (AM) scheme. Moreover, DREAM indicates that two parameters controlling autumn phenology have multiple modes in their posterior distributions while AM only identifies one mode. The application suggests that DREAM is very suitable to calibrate complex terrestrial ecosystem models, where the uncertain parameter size is usually large and existence of local optima is always a concern. In addition, this effort justifies the assumptions of the error model used in Bayesian calibration according to the residual analysis. The result indicates that a heteroscedastic, correlated, Gaussian error model is appropriate for the problem, and the consequent constructed likelihood function can alleviate the underestimation of parameter uncertainty that is usually caused by using uncorrelated error models.

  6. Artificial Light at Night Affects Organism Flux across Ecosystem Boundaries and Drives Community Structure in the Recipient Ecosystem

    Directory of Open Access Journals (Sweden)

    Alessandro Manfrin

    2017-10-01

    Full Text Available Artificial light at night (ALAN is a widespread alteration of the natural environment that can affect the functioning of ecosystems. ALAN can change the movement patterns of freshwater animals that move into the adjacent riparian and terrestrial ecosystems, but the implications for local riparian consumers that rely on these subsidies are still unexplored. We conducted a 2-year field experiment to quantify changes of freshwater-terrestrial linkages by installing streetlights in a previously light-naïve riparian area adjacent to an agricultural drainage ditch. We compared the abundance and community composition of emerging aquatic insects, flying insects, and ground-dwelling arthropods with an unlit control site. Comparisons were made within and between years using two-way generalized least squares (GLS model and a BACI design (Before-After Control-Impact. Aquatic insect emergence, the proportion of flying insects that were aquatic in origin, and the total abundance of flying insects all increased in the ALAN-illuminated area. The abundance of several night-active ground-dwelling predators (Pachygnatha clercki, Trochosa sp., Opiliones increased under ALAN and their activity was extended into the day. Conversely, the abundance of nocturnal ground beetles (Carabidae decreased under ALAN. The changes in composition of riparian predator and scavenger communities suggest that the increase in aquatic-to-terrestrial subsidy flux may cascade through the riparian food web. The work is among the first studies to experimentally manipulate ALAN using a large-scale field experiment, and provides evidence that ALAN can affect processes that link adjacent ecosystems. Given the large number of streetlights that are installed along shorelines of freshwater bodies throughout the globe, the effects could be widespread and represent an underestimated source of impairment for both aquatic and riparian systems.

  7. High resolution measurement of light in terrestrial ecosystems using photodegrading dyes.

    Directory of Open Access Journals (Sweden)

    Javier Roales

    Full Text Available Incoming solar radiation is the main determinant of terrestrial ecosystem processes, such as primary production, litter decomposition, or soil mineralization rates. Light in terrestrial ecosystems is spatially and temporally heterogeneous due to the interaction among sunlight angle, cloud cover and tree-canopy structure. To integrate this variability and to know light distribution over time and space, a high number of measurements are needed, but tools to do this are usually expensive and limited. An easy-to-use and inexpensive method that can be used to measure light over time and space is needed. We used two photodegrading fluorescent organic dyes, rhodamine WT (RWT and fluorescein, for the quantification of light. We measured dye photodegradation as the decrease in fluorescence across an irradiance gradient from full sunlight to deep shade. Then, we correlated it to accumulated light measured with PAR quantum sensors and obtained a model for this behavior. Rhodamine WT and fluorescein photodegradation followed an exponential decay curve with respect to accumulated light. Rhodamine WT degraded slower than fluorescein and remained unaltered after exposure to temperature changes. Under controlled conditions, fluorescence of both dyes decreased when temperatures increased, but returned to its initial values after cooling to the pre-heating temperature, indicating no degradation. RWT and fluorescein can be used to measure light under a varying range of light conditions in terrestrial ecosystems. This method is particularly useful to integrate solar radiation over time and to measure light simultaneously at different locations, and might be a better alternative to the expensive and time consuming traditional light measurement methods. The accuracy, low price and ease of this method make it a powerful tool for intensive sampling of large areas and for developing high resolution maps of light in an ecosystem.

  8. A review on the role of organic inputs in maintaining the soil carbon pool of the terrestrial ecosystem.

    Science.gov (United States)

    Bhattacharya, Satya Sundar; Kim, Ki-Hyun; Das, Subhasish; Uchimiya, Minori; Jeon, Byong Hun; Kwon, Eilhann; Szulejko, Jan E

    2016-02-01

    Among the numerous sources of greenhouse gases, emissions of CO2 are considerably affected by changes in the extent and type of land use, e.g., intensive agriculture, deforestation, urbanization, soil erosion, or wetland drainage. As a feasible option to control emissions from the terrestrial ecosystems, the scientific community has explored the possibility of enhancing soil carbon (C) storage capacity. Thus, restoration of damaged lands through conservation tillage, crop rotation, cover cropping, reforestation, sub-soiling of compacted lands, sustainable water management practices, and organic manuring are the major antidotes against attenuation of soil organic C (SOC) stocks. In this research, we focused on the effect of various man-made activities on soil biotic organics (e.g., green-, farm-yard manure, and composts) to understand how C fluxes from various sources contribute to the establishment of a new equilibrium in the terrestrial ecosystems. Although such inputs substitute a portion of chemical fertilizers, they all undergo activities that augment the rate and extent of decay to deplete the SOC bank. Here, we provide perspectives on the balancing factors that control the mineralization rate of organic matter. Our arguments are placed in the background of different land use types and their impacts on forests, agriculture, urbanization, soil erosion, and wetland destruction. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Nitrogen and phosphorus limitation over long-term ecosystem development in terrestrial ecosystems.

    Directory of Open Access Journals (Sweden)

    Duncan N L Menge

    Full Text Available Nutrient limitation to net primary production (NPP displays a diversity of patterns as ecosystems develop over a range of timescales. For example, some ecosystems transition from N limitation on young soils to P limitation on geologically old soils, whereas others appear to remain N limited. Under what conditions should N limitation and P limitation prevail? When do transitions between N and P limitation occur? We analyzed transient dynamics of multiple timescales in an ecosystem model to investigate these questions. Post-disturbance dynamics in our model are controlled by a cascade of rates, from plant uptake (very fast to litter turnover (fast to plant mortality (intermediate to plant-unavailable nutrient loss (slow to weathering (very slow. Young ecosystems are N limited when symbiotic N fixation (SNF is constrained and P weathering inputs are high relative to atmospheric N deposition and plant N:P demand, but P limited under opposite conditions. In the absence of SNF, N limitation is likely to worsen through succession (decades to centuries because P is mineralized faster than N. Over long timescales (centuries and longer this preferential P mineralization increases the N:P ratio of soil organic matter, leading to greater losses of plant-unavailable N versus P relative to plant N:P demand. These loss dynamics favor N limitation on older soils despite the rising organic matter N:P ratio. However, weathering depletion favors P limitation on older soils when continual P inputs (e.g., dust deposition are low, so nutrient limitation at the terminal equilibrium depends on the balance of these input and loss effects. If NPP switches from N to P limitation over long time periods, the transition time depends most strongly on the P weathering rate. At all timescales SNF has the capacity to overcome N limitation, so nutrient limitation depends critically on limits to SNF.

  10. The response of terrestrial ecosystems to global climate change: Towards an integrated approach

    International Nuclear Information System (INIS)

    Rustad, Lindsey E.

    2008-01-01

    Accumulating evidence points to an anthropogenic 'fingerprint' on the global climate change that has occurred in the last century. Climate change has, and will continue to have, profound effects on the structure and function of terrestrial ecosystems. As such, there is a critical need to continue to develop a sound scientific basis for national and international policies regulating carbon sequestration and greenhouse gas emissions. This paper reflects on the nature of current global change experiments, and provides recommendations for a unified multidisciplinary approach to future research in this dynamic field. These recommendations include: (1) better integration between experiments and models, and amongst experimental, monitoring, and space-for-time studies; (2) stable and increased support for long-term studies and multi-factor experiments; (3) explicit inclusion of biodiversity, disturbance, and extreme events in experiments and models; (4) consideration of timing vs intensity of global change factors in experiments and models; (5) evaluation of potential thresholds or ecosystem 'tipping points'; and (6) increased support for model-model and model-experiment comparisons. These recommendations, which reflect discussions within the TERACC international network of global change scientists, will facilitate the unraveling of the complex direct and indirect effects of global climate change on terrestrial ecosystems and their components

  11. The Stoichiometry of Nutrient Release by Terrestrial Herbivores and Its Ecosystem Consequences

    Directory of Open Access Journals (Sweden)

    Judith Sitters

    2017-04-01

    Full Text Available It is widely recognized that the release of nutrients by herbivores via their waste products strongly impacts nutrient availability for autotrophs. The ratios of nitrogen (N and phosphorus (P recycled through herbivore release (i.e., waste N:P are mainly determined by the stoichiometric composition of the herbivore's food (food N:P and its body nutrient content (body N:P. Waste N:P can in turn impact autotroph nutrient limitation and productivity. Herbivore-driven nutrient recycling based on stoichiometric principles is dominated by theoretical and experimental research in freshwater systems, in particular interactions between algae and invertebrate herbivores. In terrestrial ecosystems, the impact of herbivores on nutrient cycling and availability is often limited to studying carbon (C:N and C:P ratios, while the role of terrestrial herbivores in mediating N:P ratios is also likely to influence herbivore-driven nutrient recycling. In this review, we use rules and predictions on the stoichiometry of nutrient release originating from algal-based aquatic systems to identify the factors that determine the stoichiometry of nutrient release by herbivores. We then explore how these rules can be used to understand the stoichiometry of nutrient release by terrestrial herbivores, ranging from invertebrates to mammals, and its impact on plant nutrient limitation and productivity. Future studies should focus on measuring both N and P when investigating herbivore-driven nutrient recycling in terrestrial ecosystems, while also taking the form of waste product (urine or feces and other pathways by which herbivores change nutrients into account, to be able to quantify the impact of waste stoichiometry on plant communities.

  12. Net primary productivity of China's terrestrial ecosystems from a process model driven by remote sensing.

    Science.gov (United States)

    Feng, X; Liu, G; Chen, J M; Chen, M; Liu, J; Ju, W M; Sun, R; Zhou, W

    2007-11-01

    The terrestrial carbon cycle is one of the foci in global climate change research. Simulating net primary productivity (NPP) of terrestrial ecosystems is important for carbon cycle research. In this study, China's terrestrial NPP was simulated using the Boreal Ecosystem Productivity Simulator (BEPS), a carbon-water coupled process model based on remote sensing inputs. For these purposes, a national-wide database (including leaf area index, land cover, meteorology, vegetation and soil) at a 1 km resolution and a validation database were established. Using these databases and BEPS, daily maps of NPP for the entire China's landmass in 2001 were produced, and gross primary productivity (GPP) and autotrophic respiration (RA) were estimated. Using the simulated results, we explore temporal-spatial patterns of China's terrestrial NPP and the mechanisms of its responses to various environmental factors. The total NPP and mean NPP of China's landmass were 2.235 GtC and 235.2 gCm(-2)yr(-1), respectively; the total GPP and mean GPP were 4.418 GtC and 465 gCm(-2)yr(-1); and the total RA and mean RA were 2.227 GtC and 234 gCm(-2)yr(-1), respectively. On average, NPP was 50.6% of GPP. In addition, statistical analysis of NPP of different land cover types was conducted, and spatiotemporal patterns of NPP were investigated. The response of NPP to changes in some key factors such as LAI, precipitation, temperature, solar radiation, VPD and AWC are evaluated and discussed.

  13. Terrestrial ecosystems, increased solar ultraviolet radiation, and interactions with other climate change factors.

    Science.gov (United States)

    Caldwell, M M; Bornman, J F; Ballaré, C L; Flint, S D; Kulandaivelu, G

    2007-03-01

    There have been significant advances in our understanding of the effects of UV-B radiation on terrestrial ecosystems, especially in the description of mechanisms of plant response. A further area of highly interesting research emphasizes the importance of indirect UV radiation effects on plants, pathogens, herbivores, soil microbes and ecosystem processes below the surface. Although photosynthesis of higher plants and mosses is seldom affected by enhanced or reduced UV-B radiation in most field studies, effects on growth and morphology (form) of higher plants and mosses are often manifested. This can lead to small reductions in shoot production and changes in the competitive balance of different species. Fungi and bacteria are generally more sensitive to damage by UV-B radiation than are higher plants. However, the species differ in their UV-B radiation sensitivity to damage, some being affected while others may be very tolerant. This can lead to changes in species composition of microbial communities with subsequent influences on processes such as litter decomposition. Changes in plant chemical composition are commonly reported due to UV-B manipulations (either enhancement or attenuation of UV-B in sunlight) and may lead to substantial reductions in consumption of plant tissues by insects. Although sunlight does not penetrate significantly into soils, the biomass and morphology of plant root systems of plants can be modified to a much greater degree than plant shoots. Root mass can exhibit sizeable declines with more UV-B. Also, UV-B-induced changes in soil microbial communities and biomass, as well as altered populations of small invertebrates have been reported and these changes have important implications for mineral nutrient cycling in the soil. Many new developments in understanding the underlying mechanisms mediating plant response to UV-B radiation have emerged. This new information is helpful in understanding common responses of plants to UV-B radiation

  14. Disruption of the terrestrial plant ecosystem at the Cretaceous-Tertiary boundary, western interior

    Science.gov (United States)

    Tschudy, R.H.; Pillmore, C.L.; Orth, C.J.; Gilmore, J.S.; Knight, J.D.

    1984-01-01

    The palynologically defined Cretaceous-Tertiary boundary in the western interior of North America occurs at the top of an iridium-rich clay layer. The boundary is characterized by the abrupt disappearance of certain pollen species, immediately followed by a pronounced, geologically brief change in the ratio of fern spores to angiosperm pollen. The occurrence of these changes at two widely separated sites implies continentwide disruption of the terrestrial ecosystem, probably caused by a major catastrophic event at the end of the period.

  15. Mercury Exposure Affects the Reproductive Success of a Free-living Terrestrial Songbird, the Carolina Wren, (Thryothrus ludovicianus)

    Science.gov (United States)

    The impacts of mercury contamination on aquatic-feeding wildlife are well-established, but recent attention has focused on the effects of mercury on species in terrestrial ecosystems. Despite mounting evidence of mercury accumulation in terrestrial ecosystems, there is little dat...

  16. The greenhouse gas balance of Italy. An insight on managed and natural terrestrial ecosystems

    International Nuclear Information System (INIS)

    Valentini, Riccardo; Miglietta, Franco

    2015-01-01

    Comprehensively addresses the full greenhouse gases budget of the Italian landscape. Presents the results of the national project CARBOITALY. Provides new data and analyses in the framework of climate policies. The book addresses in a comprehensive way the full greenhouse gases budget of the Italian landscape, focusing on land use and terrestrial ecosystems. In recent years there has been a growing interest in the role of terrestrial ecosystems with regard to the carbon cycle and only recently a regional approach has been considered for its specificity in terms of new methodologies for observations and models and its relevance for national policies on mitigation and adaptation to climate changes. In terms of methods this book describes the role of flux networks and data-driven models, airborne regional measurements of fluxes and specific sectoral approaches related to important components of the human and natural landscapes. There is also a growing need on the part of institutions, agencies and policy stakeholders for new data and analyses enabling them to improve their national inventories of greenhouse gases and their compliance with the UNFCCC process. In this respect the data presented is a basis for a full carbon accounting and available to relevant stakeholders for improvements and/or verification of national inventories. The wealth of research information is the result of a national project, CARBOITALY, which involved 15 Italian institutions and several researchers to provide new data and analyses in the framework of climate policies.

  17. The greenhouse gas balance of Italy. An insight on managed and natural terrestrial ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Valentini, Riccardo [Tuscia Univ., Viterbo (Italy). Dept. for Innovation in Biological, Agro-Food and Forest System (DIBAF); Euro-Mediterranean Center on Climate Changes (CMCC), Viterbo (Italy). Impacts on Agriculture, Forest and Natural Ecosystem Division (IAFENT); Miglietta, Franco (ed.) [National Research Council of Italy (CNR) and Edmund Mach Foundation, San Michele all' Adige (Italy). FoxLab Inst. of Biometeorology

    2015-04-01

    Comprehensively addresses the full greenhouse gases budget of the Italian landscape. Presents the results of the national project CARBOITALY. Provides new data and analyses in the framework of climate policies. The book addresses in a comprehensive way the full greenhouse gases budget of the Italian landscape, focusing on land use and terrestrial ecosystems. In recent years there has been a growing interest in the role of terrestrial ecosystems with regard to the carbon cycle and only recently a regional approach has been considered for its specificity in terms of new methodologies for observations and models and its relevance for national policies on mitigation and adaptation to climate changes. In terms of methods this book describes the role of flux networks and data-driven models, airborne regional measurements of fluxes and specific sectoral approaches related to important components of the human and natural landscapes. There is also a growing need on the part of institutions, agencies and policy stakeholders for new data and analyses enabling them to improve their national inventories of greenhouse gases and their compliance with the UNFCCC process. In this respect the data presented is a basis for a full carbon accounting and available to relevant stakeholders for improvements and/or verification of national inventories. The wealth of research information is the result of a national project, CARBOITALY, which involved 15 Italian institutions and several researchers to provide new data and analyses in the framework of climate policies.

  18. Characteristics of terrestrial and aquatic ecosystems of two locations in Deaf Smith and Swisher Counties, Texas

    International Nuclear Information System (INIS)

    1984-11-01

    According to the Civilian Radioactive Waste Management Program and the Nuclear Waste Policy Act of 1982 (P.L. 97-425), a potential nuclear waste repository site must be chosen with consideration of potential impacts on terrestrial and aquatic ecosystems. This report is a preliminary environmental characterization of two locations in the Texas Panhandle, one in Deaf Smith County and the other in Swisher County, that have been recommended for further study. A description of important natural areas is offered as a basis for comparative studies of the two locations and for the identification and screening of potential repository sites. Information on current land uses, potential habitats, and expected plant and wildlife species is provided to assist field investigators in the collection of baseline data in support of further siting activities. The results of limited field surveys are also included. The report is in two parts. Part I contains a characterization of terrestrial ecological resources based upon limited field surveys aimed at verifying the presence of plant communities and wildlife habitats. It also presents inventories of species with special status, species with recreational and economic importance, and species of ecological value to important or special-status species. Part II presents information on aquatic ecosystems and resources derived primarily from a review of the literature, interviews, and limited field surveys. 21 figures, 18 tables

  19. Biological nitrogen fixation: rates, patterns and ecological controls in terrestrial ecosystems

    Science.gov (United States)

    Vitousek, Peter M.; Menge, Duncan N.L.; Reed, Sasha C.; Cleveland, Cory C.

    2013-01-01

    New techniques have identified a wide range of organisms with the capacity to carry out biological nitrogen fixation (BNF)—greatly expanding our appreciation of the diversity and ubiquity of N fixers—but our understanding of the rates and controls of BNF at ecosystem and global scales has not advanced at the same pace. Nevertheless, determining rates and controls of BNF is crucial to placing anthropogenic changes to the N cycle in context, and to understanding, predicting and managing many aspects of global environmental change. Here, we estimate terrestrial BNF for a pre-industrial world by combining information on N fluxes with 15N relative abundance data for terrestrial ecosystems. Our estimate is that pre-industrial N fixation was 58 (range of 40–100) Tg N fixed yr−1; adding conservative assumptions for geological N reduces our best estimate to 44 Tg N yr−1. This approach yields substantially lower estimates than most recent calculations; it suggests that the magnitude of human alternation of the N cycle is substantially larger than has been assumed.

  20. Inter-annual variabilities in biogeophysical feedback of terrestrial ecosystem to atmosphere using a land surface model

    Science.gov (United States)

    Seo, C.; Hong, S.; Jeong, H. M.; Jeon, J.

    2017-12-01

    Biogeophysical processes of terrestrial ecosystem such as water vapor and energy flux are the key features to understand ecological feedback to atmospheric processes and thus role of terrestrial ecosystem in climate system. For example, it has been recently known that the ecological feedback through water vapor and energy flux results in regulating regional weathers and climates which is one of the fundamental functions of terrestrial ecosystem. In regional scale, water vapor flux has been known to give negative feedback to atmospheric warming, while energy flux from the surface has been known to positive feedback. In this study, we explored the inter-annual variabilities in these two biogeophysical features to see how the climate regulating functions of terrestrial ecosystem have been changed with climate change. We selected a land surface model involving vegetation dynamics that is forced by atmospheric data from NASA including precipitation, temperature, wind, surface pressure, humidity, and incoming radiations. From the land surface model, we simulated 60-year water vapor and energy fluxes from 1961 to 2010, and calculates feedbacks of terrestrial ecosystem as in radiation amount into atmosphere. Then, we analyzed the inter-annual variabilities in the feedbacks. The results showed that some mid-latitude areas showing very high variabilities in precipitation showed higher positive feedback and/or lower negative feedback. These results suggest deterioration of the biogeophyisical factor of climate regulating function over those regions.

  1. Neotropical Amphibian Declines Affect Stream Ecosystem Properties

    Science.gov (United States)

    Connelly, S.; Pringle, C. M.; Bixby, R. J.; Whiles, M. R.; Lips, K. R.; Brenes, R.; Colon-Gaud, J. C.; Kilham, S.; Hunte-Brown, M.

    2005-05-01

    Global declines of amphibians are well documented, yet effects of these dramatic losses on ecosystem structure and function are poorly understood. As part of a larger collaborative project, we compared two upland Panamanian streams. Both streams are biologically and geologically similar; however, one stream (Fortuna) has recently experienced almost complete extirpation of stream-dwelling frogs, while the other (Cope) still has intact populations. We experimentally excluded tadpoles from localized areas in each stream. We then compared chlorophyll a, algal community composition, ash-free dry mass (AFDM), inorganic matter, and insect assemblages in control and exclusion areas. Additionally, we sampled the natural substrate of both streams monthly for chlorophyll a, algal community composition, AFDM, and inorganic matter. At Cope, chlorophyll a, AFDM, and inorganic matter were greater in areas where tadpoles were excluded than in their presence. Numbers of dominant algal species (e.g., Nupela praecipua and Eunotia siolii) were greater in the exclusion versus control treatments. Monthly sampling of natural substrate indicated higher chlorophyll a and AFDM at Cope compared to Fortuna. Our data suggest that stream-dwelling anuran larvae have significant impacts on algal communities. These results also have implications for predicting the relevance of short-term experimental manipulations to long-term, whole-stream processes.

  2. Rare earth elements in freshwater, marine, and terrestrial ecosystems in the eastern Canadian Arctic.

    Science.gov (United States)

    MacMillan, Gwyneth Anne; Chételat, John; Heath, Joel P; Mickpegak, Raymond; Amyot, Marc

    2017-10-18

    Few ecotoxicological studies exist for rare earth elements (REEs), particularly field-based studies on their bioaccumulation and food web dynamics. REE mining has led to significant environmental impacts in several countries (China, Brazil, U.S.), yet little is known about the fate and transport of these contaminants of emerging concern. Northern ecosystems are potentially vulnerable to REE enrichment from prospective mining projects at high latitudes. To understand how REEs behave in remote northern food webs, we measured REE concentrations and carbon and nitrogen stable isotope ratios (∂ 15 N, ∂ 13 C) in biota from marine, freshwater, and terrestrial ecosystems of the eastern Canadian Arctic (N = 339). Wildlife harvesting and tissue sampling was partly conducted by local hunters through a community-based monitoring project. Results show that REEs generally follow a coherent bioaccumulation pattern for sample tissues, with some anomalies for redox-sensitive elements (Ce, Eu). Highest REE concentrations were found at low trophic levels, especially in vegetation and aquatic invertebrates. Terrestrial herbivores, ringed seal, and fish had low total REE levels in muscle tissue (∑REE for 15 elements <0.1 nmol g -1 ), yet accumulation was an order of magnitude higher in liver tissues. Age- and length-dependent REE accumulation also suggest that REE uptake is faster than elimination for some species. Overall, REE bioaccumulation patterns appear to be species- and tissue-specific, with limited potential for biomagnification. This study provides novel data on the behaviour of REEs in ecosystems and will be useful for environmental impact assessment of REE enrichment in northern regions.

  3. Rainfall changes affect the algae dominance in tank bromeliad ecosystems

    Science.gov (United States)

    Pires, Aliny Patricia Flauzino; Leal, Juliana da Silva; Peeters, Edwin T. H. M.

    2017-01-01

    Climate change and biodiversity loss have been reported as major disturbances in the biosphere which can trigger changes in the structure and functioning of natural ecosystems. Nonetheless, empirical studies demonstrating how both factors interact to affect shifts in aquatic ecosystems are still unexplored. Here, we experimentally test how changes in rainfall distribution and litter diversity affect the occurrence of the algae-dominated condition in tank bromeliad ecosystems. Tank bromeliads are miniature aquatic ecosystems shaped by the rainwater and allochthonous detritus accumulated in the bases of their leaves. Here, we demonstrated that changes in the rainfall distribution were able to reduce the chlorophyll-a concentration in the water of bromeliad tanks affecting significantly the occurrence of algae-dominated conditions. On the other hand, litter diversity did not affect the algae dominance irrespective to the rainfall scenario. We suggest that rainfall changes may compromise important self-reinforcing mechanisms responsible for maintaining high levels of algae on tank bromeliads ecosystems. We summarized these results into a theoretical model which suggests that tank bromeliads may show two different regimes, determined by the bromeliad ability in taking up nutrients from the water and by the total amount of light entering the tank. We concluded that predicted climate changes might promote regime shifts in tropical aquatic ecosystems by shaping their structure and the relative importance of other regulating factors. PMID:28422988

  4. The Rise of the Anthroposphere since 50,000 Years: An Ecological Replacement of Megaherbivores by Humans in Terrestrial Ecosystems?

    Directory of Open Access Journals (Sweden)

    Hervé Bocherens

    2018-01-01

    Full Text Available Megaherbivores fulfilled a number of important ecological functions in terrestrial ecosystems and behaved as ecological engineers since 300 million years until around 12,000 years ago. These essential ecological functions include opening vegetation cover, selective seed dispersal and nutrient recycling and spreading. Thanks to these effects, megaherbivores change the vegetation structure where they live, with cascading effects on smaller herbivores and also on climate. The late Pleistocene extinction strongly impacted the megaherbivores almost all over the world and led to the loss of these important ecological functions in terrestrial ecosystems. These functions were partially restored by agriculturist humans through an ecological replacement that occurred through an ecological shift within the species Homo sapiens. A better understanding of the differences and similarities between the ecological impacts of megaherbivores and those of agricultural humans should help to predict the future of terrestrial ecosystems.

  5. Recent Changes in Global Photosynthesis and Terrestrial Ecosystem Respiration Constrained From Multiple Observations

    Science.gov (United States)

    Li, Wei; Ciais, Philippe; Wang, Yilong; Yin, Yi; Peng, Shushi; Zhu, Zaichun; Bastos, Ana; Yue, Chao; Ballantyne, Ashley P.; Broquet, Grégoire; Canadell, Josep G.; Cescatti, Alessandro; Chen, Chi; Cooper, Leila; Friedlingstein, Pierre; Le Quéré, Corinne; Myneni, Ranga B.; Piao, Shilong

    2018-01-01

    To assess global carbon cycle variability, we decompose the net land carbon sink into the sum of gross primary productivity (GPP), terrestrial ecosystem respiration (TER), and fire emissions and apply a Bayesian framework to constrain these fluxes between 1980 and 2014. The constrained GPP and TER fluxes show an increasing trend of only half of the prior trend simulated by models. From the optimization, we infer that TER increased in parallel with GPP from 1980 to 1990, but then stalled during the cooler periods, in 1990-1994 coincident with the Pinatubo eruption, and during the recent warming hiatus period. After each of these TER stalling periods, TER is found to increase faster than GPP, explaining a relative reduction of the net land sink. These results shed light on decadal variations of GPP and TER and suggest that they exhibit different responses to temperature anomalies over the last 35 years.

  6. Levels and transfer of 210Po and 210Pb in Nordic terrestrial ecosystems

    DEFF Research Database (Denmark)

    Brown, J.E.; Gjelsvik, R.; Roos, Per

    2011-01-01

    concentrations of the main dose forming radionuclides 210Po and 210Pb in biota from terrestrial ecosystems thus providing insight into the behaviour of these radioisotopes. Samples of soil, plants and animals were collected at Dovrefjell, Central Norway and Olkiluoto, Finland. Soil profiles from Dovrefjell...... exhibited an approximately exponential fall in 210Pb activity concentrations from elevated levels in humus/surface soils to “supported” levels at depth. Activity concentrations of 210Po in fauna (invertebrates, mammals, birds) ranged between 2 and 123 Bq kg−1 d.w. and in plants and lichens between 20...... and 138 Bq kg−1 d.w.. The results showed that soil humus is an important reservoir for 210Po and 210Pb and that fauna in close contact with this media may also exhibit elevated levels of 210Po. Concentration ratios appear to have limited applicability with regards to prediction of activity concentrations...

  7. Green Ocean Amazon 2014/15 Terrestrial Ecosystem Project (Geco) Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Jardine, Kolby [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2016-06-01

    In conjunction with the U.S. Department of Energy (DOE)’s Atmospheric Radiation Measurement (ARM) Climate Research Facility GoAmazon campaign, the Terrestrial Ecosystem Science (TES)-funded Green Ocean Amazon (GoAmazon 2014/15) terrestrial ecosystem project (Geco) was designed to: • evaluate the strengths and weaknesses of leaf-level algorithms for biogenic volatile organic compounds (BVOCs) emissions in Amazon forests near Manaus, Brazil, and • conduct mechanistic field studies to characterize biochemical and physiological processes governing leaf- and landscape-scale tropical forest BVOC emissions, and the influence of environmental drivers that are expected to change with a warming climate. Through a close interaction between modeling and observational activities, including the training of MS and PhD graduate students, post-doctoral students, and technicians at the National Institute for Amazon Research (INPA), the study aimed at improving the representation of BVOC-mediated biosphere-atmosphere interactions and feedbacks under a warming climate. BVOCs can form cloud condensation nuclei (CCN) that influence precipitation dynamics and modify the quality of down welling radiation for photosynthesis. However, our ability to represent these coupled biosphere-atmosphere processes in Earth system models suffers from poor understanding of the functions, identities, quantities, and seasonal patterns of BVOC emissions from tropical forests as well as their biological and environmental controls. The Model of Emissions of Gases and Aerosols from Nature (MEGAN), the current BVOC sub-model of the Community Earth System Model (CESM), was evaluated to explore mechanistic controls over BVOC emissions. Based on that analysis, a combination of observations and experiments were studied in forests near Manaus, Brazil, to test existing parameterizations and algorithm structures in MEGAN. The model was actively modified as needed to improve tropical BVOC emission simulations on

  8. Modelling accumulation of radionuclides in terrestrial ecosystems originating from a long-term groundwater contamination

    Energy Technology Data Exchange (ETDEWEB)

    Gaerdenaes, Annemieke I. [Dept. of Soil and Environment, Swedish University of Agricultural Sciences (SLU), P.O. Box 7001, 750 07 Uppsala (Sweden); Eckersten, Henrik [Dept. of Ecology and Crop Production, SLU, P.O. Box 7042, 750 07 Uppsala (Sweden); Reinlert, Andre [Dept. of Physical Geography and Ecosystems Analysis, Lund University, 223 62 Lund (Sweden); MMT, Sven Kaellfelts Gata 11 SE 426 71 Vaestra Froelunda (Sweden); Gustafsson, David; Jansson, Per-Erik [Dept. Land and Water Resources, KTH, SE 100 44, Stockholm (Sweden); Ekstroem, Per-Anders [Facilia AB, Gustavlundsvaegen 151A, 167 51 Bromma (Sweden); Greger, Maria [Dept. of Ecology, Environment and Plant Sciences, Stockholm University, 106 91 Stockholm (Sweden)

    2014-07-01

    This study was conducted as part of the risk assessment of final deposits of nuclear fuel waste. The overall objective is to assess the possible accumulation of radionuclides in terrestrial ecosystems after an eventual long-term groundwater contamination. The specific objectives are to assess: i) What proportion of the contamination will accumulate in the soil-plant-system? ii) Where in the soil-plant- system will it accumulate? iii) Which ecosystem characteristics and radionuclides properties are important for the accumulation? and iv) Under which circumstances do losses from the ecosystems occur? We developed the dynamic model Tracey (Gaerdenaes et al. 2009) describing cycling of radionuclides in terrestrial ecosystems with high temporal resolution (1 day). The model is a multi-compartmental model in which fluxes and storage of radionuclides are described for different plant parts and soil pools in each of the 10 soil layers. The radionuclide fluxes are driven either by water or carbon fluxes. The water and the carbon fluxes are simulated with the dynamic, bio-geophysical Coup Model (Jansson and Karlberg, 2004). Tracey includes two root uptake approaches of radionuclides; (i) passive uptake driven by root water uptake and (ii) active uptake driven by plant growth. A linear approach describes the adsorption of radionuclides to soil particles and organic matter. Tracey was applied on two ecosystems with contrasting hydrology, the mixed Pinus-Picea forests found in the dry, elevated areas and the Alnus forests found in the wet, low-land areas of Uppland in central east Sweden. Different varieties of the two forest types were created by varying the root depth and radiation use efficiency. The climate was cold-temperate and based on 30-year daily weather data from Uppsala. The assumed groundwater contamination was close to 1 mg of an unspecified radionuclide per m2 and year. This load corresponds to 1 Bq per m{sup 2} and year of {sup 238}U, a common long

  9. Multiproxy evidence for terrestrial and aquatic ecosystem responses during the 8.2 ka cold event as recorded at Højby Sø, Denmark

    DEFF Research Database (Denmark)

    Hede, Mikkel Ulfeldt; Rasmussen, Peter; Noe-Nygaard, Nanna

    2010-01-01

    ecosystems to the 8.2 ka cold event. A reduced pollen production by thermophilous deciduous tree taxa in the period c. 8250–8000 cal yr BP reveal that the forest ecosystem was affected by low temperatures during the summer and winter/early-spring seasons. This finding is consistent with the timing of the 8.......2 ka cold event as registered in the Greenland ice cores. At Højby Sø, the climate anomaly appears to have started 200–250 yr earlier than the 8.2 ka cold event as the lake proxy data provide strong evidence for a precipitation-induced distinct increase in catchment soil erosion beginning around 8500...... cal yr BP. Alteration of the terrestrial environment then resulted in a major aquatic ecosystem change with nutrient enrichment of the lake and enhanced productivity, which lasted until c. 7900 cal yr BP. Keywords: 8.2 ka cold event; Lake sediments; Palaeoclimate; Pollen; Macrofossils; Geochemistry...

  10. The behavior of 89Sr and tritium water (HTO) in a model terrestrial-aquatic ecosystem

    International Nuclear Information System (INIS)

    Zhang Yongxi; Wang Shouxiang; Chen Chuangqun; Sun Zhiming; Huang Dan; Hu Bingmin

    1993-08-01

    The effect of land polluted by 89 Sr on water body and the immigration of HTO from water body to land were studied in a modelling terrestrial-aquatic ecosystem. The results are as follows: (1) The 89 Sr in soil quickly migrated to common bean plants and its concentration in common bean plants was increasing with the time, but the concentration of 89 Sr in soil was exponentially declining with the depth. About 5% of 89 Sr was migrated to water body by rainfall then distributed to other components, and it can be concentrated by aquatics in a certain degree. (2) when HTO entered into the water body, it would migrate to other components of the ecosystem. and the HTO in the pool was linearly decreasing with the time. However, the concentration of HTO in the sediments and aquatics would firstly increase then reached the peak and went down. The tritium of HTO was existed in two forms in the sediments and aquatics, free water (HTO) and bound tritium. HTO was also migrated to the adjacent land soil and absorbed by land crop plants, within one and half months the land system contained 24% of the total tritium in the aquatic system

  11. Deriving Vegetation Dynamics of Natural Terrestrial Ecosystems from MODIS NDVI/EVI Data over Turkey.

    Science.gov (United States)

    Evrendilek, Fatih; Gulbeyaz, Onder

    2008-09-01

    The 16-day composite MODIS vegetation indices (VIs) at 500-m resolution for the period between 2000 to 2007 were seasonally averaged on the basis of the estimated distribution of 16 potential natural terrestrial ecosystems (NTEs) across Turkey. Graphical and statistical analyses of the time-series VIs for the NTEs spatially disaggregated in terms of biogeoclimate zones and land cover types included descriptive statistics, correlations, discrete Fourier transform (DFT), time-series decomposition, and simple linear regression (SLR) models. Our spatio-temporal analyses revealed that both MODIS VIs, on average, depicted similar seasonal variations for the NTEs, with the NDVI values having higher mean and SD values. The seasonal VIs were most correlated in decreasing order for: barren/sparsely vegetated land > grassland > shrubland/woodland > forest; (sub)nival > warm temperate > alpine > cool temperate > boreal = Mediterranean; and summer > spring > autumn > winter. Most pronounced differences between the MODIS VI responses over Turkey occurred in boreal and Mediterranean climate zones and forests, and in winter (the senescence phase of the growing season). Our results showed the potential of the time-series MODIS VI datasets in the estimation and monitoring of seasonal and interannual ecosystem dynamics over Turkey that needs to be further improved and refined through systematic and extensive field measurements and validations across various biomes.

  12. Ground-based grasslands data to support remote sensing and ecosystem modeling of terrestrial primary production

    Science.gov (United States)

    Olson, R. J.; Scurlock, J. M. O.; Turner, R. S.; Jennings, S. V.

    1995-01-01

    Estimating terrestrial net primary production (NPP) using remote-sensing tools and ecosystem models requires adequate ground-based measurements for calibration, parameterization, and validation. These data needs were strongly endorsed at a recent meeting of ecosystem modelers organized by the International Geosphere-Biosphere Program's (IGBP's) Data and Information System (DIS) and its Global Analysis, Interpretation, and Modelling (GAIM) Task Force. To meet these needs, a multinational, multiagency project is being coordinated by the IGBP DIS to compile existing NPP data from field sites and to regionalize NPP point estimates to various-sized grid cells. Progress at Oak Ridge National Laboratory (ORNL) on compiling NPP data for grasslands as part of the IGBP DIS data initiative is described. Site data and associated documentation from diverse field studies are being acquired for selected grasslands and are being reviewed for completeness, consistency, and adequacy of documentation, including a description of sampling methods. Data are being compiled in a database with spatial, temporal, and thematic characteristics relevant to remote sensing and global modeling. NPP data are available from the ORNL Distributed Active Archive Center (DAAC) for biogeochemical dynamics. The ORNL DAAC is part of the Earth Observing System Data and Information System, of the US National Aeronautics and Space Administration.

  13. Ground-based grasslands data to support remote sensing and ecosystem modeling of terrestrial primary production

    Energy Technology Data Exchange (ETDEWEB)

    Olson, R.J.; Turner, R.S. [Oak Ridge National Lab., TN (United States); Scurlock, J.M.O. [King`s College London, (England); Jennings, S.V. [Tennessee Univ., Knoxville, TN (United States)

    1995-12-31

    Estimating terrestrial net primary production (NPP) using remote- sensing tools and ecosystem models requires adequate ground-based measurements for calibration, parameterization, and validation. These data needs were strongly endorsed at a recent meeting of ecosystem modelers organized by the International Geosphere-Biosphere Programme`s (IGBP`s) Data and Information System (DIS) and its Global Analysis, Interpretation, and Modelling (GAIM) Task Force. To meet these needs, a multinational, multiagency project is being coordinated by the IGBP DIS to compile existing NPP data from field sites and to regionalize NPP point estimates to various-sized grid cells. Progress at Oak Ridge National Laboratory (ORNL) on compiling NPP data for grasslands as part of the IGBP DIS data initiative is described. Site data and associated documentation from diverse field studies are being acquired for selected grasslands and are being reviewed for completeness, consistency, and adequacy of documentation, including a description of sampling methods. Data are being compiled in a database with spatial, temporal, and thematic characteristics relevant to remote sensing and global modeling. NPP data are available from the ORNL Distributed Active Archive Center (DAAC) for biogeochemical dynamics. The ORNL DAAC is part of the Earth Observing System Data and Information System, of the US National Aeronautics and Space Administration.

  14. Direct and indirect effects of climatic variations on the interannual variability in net ecosystem exchange across terrestrial ecosystems

    Directory of Open Access Journals (Sweden)

    Junjiong Shao

    2016-08-01

    Full Text Available Climatic variables not only directly affect the interannual variability (IAV in net ecosystem exchange of CO2 (NEE but also indirectly drive it by changing the physiological parameters. Identifying these direct and indirect paths can reveal the underlying mechanisms of carbon (C dynamics. In this study, we applied a path analysis using flux data from 65 sites to quantify the direct and indirect climatic effects on IAV in NEE and to evaluate the potential relationships among the climatic variables and physiological parameters that represent physiology and phenology of ecosystems. We found that the maximum photosynthetic rate was the most important factor for the IAV in gross primary productivity (GPP, which was mainly induced by the variation in vapour pressure deficit. For ecosystem respiration (RE, the most important drivers were GPP and the reference respiratory rate. The biome type regulated the direct and indirect paths, with distinctive differences between forests and non-forests, evergreen needleleaf forests and deciduous broadleaf forests, and between grasslands and croplands. Different paths were also found among wet, moist and dry ecosystems. However, the climatic variables can only partly explain the IAV in physiological parameters, suggesting that the latter may also result from other biotic and disturbance factors. In addition, the climatic variables related to NEE were not necessarily the same as those related to GPP and RE, indicating the emerging difficulty encountered when studying the IAV in NEE. Overall, our results highlight the contribution of certain physiological parameters to the IAV in C fluxes and the importance of biome type and multi-year water conditions, which should receive more attention in future experimental and modelling research.

  15. Radioactive characterization of the terrestrial ecosystem in the area of location of the Juragua Nuclear Power Plant

    International Nuclear Information System (INIS)

    Sibello Hernandez, R.Y.; Alonso Hernandez, C.M.; Diaz Asencio, M.; Cartas Aguila, H. A.

    1999-01-01

    In this work the results are exposed obtained by the Laboratory of Environmental Surveillance in the radioactive characterization of the existent terrestrial ecosystem in the area of location of the Juragua Nuclear Power Plants in Cienfuegos, Cuba, starting from 1986 and up to 1993

  16. Terrestrial Carbon Sinks in the Brazilian Amazon and Cerrado Region Predicted from MODIS Satellite Data and Ecosystem Modeling

    Science.gov (United States)

    A simulation model based on satellite observations of monthly vegetation cover from the Moderate Resolution Imaging Spectroradiometer (MODIS) was used to estimate monthly carbon fluxes in terrestrial ecosystems of Brazilian Amazon and Cerrado regions over the period 2000-2004. Pr...

  17. Solar ultraviolet radiation and ozone depletion-driven climate change: effects on terrestrial ecosystems.

    Science.gov (United States)

    Bornman, J F; Barnes, P W; Robinson, S A; Ballaré, C L; Flint, S D; Caldwell, M M

    2015-01-01

    In this assessment we summarise advances in our knowledge of how UV-B radiation (280-315 nm), together with other climate change factors, influence terrestrial organisms and ecosystems. We identify key uncertainties and knowledge gaps that limit our ability to fully evaluate the interactive effects of ozone depletion and climate change on these systems. We also evaluate the biological consequences of the way in which stratospheric ozone depletion has contributed to climate change in the Southern Hemisphere. Since the last assessment, several new findings or insights have emerged or been strengthened. These include: (1) the increasing recognition that UV-B radiation has specific regulatory roles in plant growth and development that in turn can have beneficial consequences for plant productivity via effects on plant hardiness, enhanced plant resistance to herbivores and pathogens, and improved quality of agricultural products with subsequent implications for food security; (2) UV-B radiation together with UV-A (315-400 nm) and visible (400-700 nm) radiation are significant drivers of decomposition of plant litter in globally important arid and semi-arid ecosystems, such as grasslands and deserts. This occurs through the process of photodegradation, which has implications for nutrient cycling and carbon storage, although considerable uncertainty exists in quantifying its regional and global biogeochemical significance; (3) UV radiation can contribute to climate change via its stimulation of volatile organic compounds from plants, plant litter and soils, although the magnitude, rates and spatial patterns of these emissions remain highly uncertain at present. UV-induced release of carbon from plant litter and soils may also contribute to global warming; and (4) depletion of ozone in the Southern Hemisphere modifies climate directly via effects on seasonal weather patterns (precipitation and wind) and these in turn have been linked to changes in the growth of plants

  18. Convergence and Divergence in a Multi-Model Ensemble of Terrestrial Ecosystem Models in North America

    Science.gov (United States)

    Dungan, J. L.; Wang, W.; Hashimoto, H.; Michaelis, A.; Milesi, C.; Ichii, K.; Nemani, R. R.

    2009-12-01

    In support of NACP, we are conducting an ensemble modeling exercise using the Terrestrial Observation and Prediction System (TOPS) to evaluate uncertainties among ecosystem models, satellite datasets, and in-situ measurements. The models used in the experiment include public-domain versions of Biome-BGC, LPJ, TOPS-BGC, and CASA, driven by a consistent set of climate fields for North America at 8km resolution and daily/monthly time steps over the period of 1982-2006. The reference datasets include MODIS Gross Primary Production (GPP) and Net Primary Production (NPP) products, Fluxnet measurements, and other observational data. The simulation results and the reference datasets are consistently processed and systematically compared in the climate (temperature-precipitation) space; in particular, an alternative to the Taylor diagram is developed to facilitate model-data intercomparisons in multi-dimensional space. The key findings of this study indicate that: the simulated GPP/NPP fluxes are in general agreement with observations over forests, but are biased low (underestimated) over non-forest types; large uncertainties of biomass and soil carbon stocks are found among the models (and reference datasets), often induced by seemingly “small” differences in model parameters and implementation details; the simulated Net Ecosystem Production (NEP) mainly responds to non-respiratory disturbances (e.g. fire) in the models and therefore is difficult to compare with flux data; and the seasonality and interannual variability of NEP varies significantly among models and reference datasets. These findings highlight the problem inherent in relying on only one modeling approach to map surface carbon fluxes and emphasize the pressing necessity of expanded and enhanced monitoring systems to narrow critical structural and parametrical uncertainties among ecosystem models.

  19. Diagnosing phosphorus limitations in natural terrestrial ecosystems in carbon cycle models

    Science.gov (United States)

    Sun, Yan; Peng, Shushi; Goll, Daniel S.; Ciais, Philippe; Guenet, Bertrand; Guimberteau, Matthieu; Hinsinger, Philippe; Janssens, Ivan A.; Peñuelas, Josep; Piao, Shilong; Poulter, Benjamin; Violette, Aurélie; Yang, Xiaojuan; Yin, Yi; Zeng, Hui

    2017-07-01

    Most of the Earth System Models (ESMs) project increases in net primary productivity (NPP) and terrestrial carbon (C) storage during the 21st century. Despite empirical evidence that limited availability of phosphorus (P) may limit the response of NPP to increasing atmospheric CO2, none of the ESMs used in the previous Intergovernmental Panel on Climate Change assessment accounted for P limitation. We diagnosed from ESM simulations the amount of P need to support increases in carbon uptake by natural ecosystems using two approaches: the demand derived from (1) changes in C stocks and (2) changes in NPP. The C stock-based additional P demand was estimated to range between -31 and 193 Tg P and between -89 and 262 Tg P for Representative Concentration Pathway (RCP) 2.6 and RCP8.5, respectively, with negative values indicating a P surplus. The NPP-based demand, which takes ecosystem P recycling into account, results in a significantly higher P demand of 648-1606 Tg P for RCP2.6 and 924-2110 Tg P for RCP8.5. We found that the P demand is sensitive to the turnover of P in decomposing plant material, explaining the large differences between the NPP-based demand and C stock-based demand. The discrepancy between diagnosed P demand and actual P availability (potential P deficit) depends mainly on the assumptions about availability of the different soil P forms. Overall, future P limitation strongly depends on both soil P availability and P recycling on ecosystem scale.

  20. Aspects of the carbon cycle in terrestrial ecosystems of Northeastern Smaaland

    Energy Technology Data Exchange (ETDEWEB)

    Tagesson, Torbern [Lund Univ., Geobiosphere Science Centre (Sweden). Physical Geography and Ecosystems Analysis

    2006-02-15

    Boreal and temperate ecosystems of the northern hemisphere are important for the future development of global climate. In this study, the carbon cycle has been studied in a pine forest, a meadow, a spruce forest and two deciduous forests in the Simpevarp investigation area in southern Sweden (57 deg 5 min N, 34 deg 55 min E). Ground respiration and ground Gross Primary Production (GPP) has been measured three times during spring 2004 with the closed chamber technique. Soil temperature, soil moisture and Photosynthetically Active Radiation (PAR) were also measured. An exponential regression with ground respiration against soil temperature was used to extrapolate respiration over spring 2004. A logarithmic regression with ground GPP against PAR was used to extrapolate GPP in meadow over spring 2004. Ground respiration is affected by soil temperature in all ecosystems but pine, but still it only explains a small part of the variation in respiration and this indicates that other abiotic factors also have an influence. Soil moisture affects respiration in spruce and one of the deciduous ecosystems. A comparison between measured and extrapolated ground respiration indicated that soil temperature could be used to extrapolate ground respiration. PAR is the main factor influencing GPP in all ecosystems but pine, still it could not be used to extrapolate GPP in meadow since too few measurements were done and they were from different periods of spring. Soil moisture did not have any significant effect on GPP. A Dynamic Global Vegetation Model, a DGVM called LPJ-GUESS, was downscaled to the Simpevarp investigation area. The downscaled DGVM was evaluated against measured respiration and soil organic acids for all five ecosystems. In meadow, it was evaluated against Net Primary Production, NPP. For the forest ecosystems, it was evaluated against tree layer carbon pools. The evaluation indicated that the DGVM is reasonably well downscaled to the Simpevarp investigation area and

  1. Aspects of the carbon cycle in terrestrial ecosystems of Northeastern Smaaland

    International Nuclear Information System (INIS)

    Tagesson, Torbern

    2006-02-01

    Boreal and temperate ecosystems of the northern hemisphere are important for the future development of global climate. In this study, the carbon cycle has been studied in a pine forest, a meadow, a spruce forest and two deciduous forests in the Simpevarp investigation area in southern Sweden (57 deg 5 min N, 34 deg 55 min E). Ground respiration and ground Gross Primary Production (GPP) has been measured three times during spring 2004 with the closed chamber technique. Soil temperature, soil moisture and Photosynthetically Active Radiation (PAR) were also measured. An exponential regression with ground respiration against soil temperature was used to extrapolate respiration over spring 2004. A logarithmic regression with ground GPP against PAR was used to extrapolate GPP in meadow over spring 2004. Ground respiration is affected by soil temperature in all ecosystems but pine, but still it only explains a small part of the variation in respiration and this indicates that other abiotic factors also have an influence. Soil moisture affects respiration in spruce and one of the deciduous ecosystems. A comparison between measured and extrapolated ground respiration indicated that soil temperature could be used to extrapolate ground respiration. PAR is the main factor influencing GPP in all ecosystems but pine, still it could not be used to extrapolate GPP in meadow since too few measurements were done and they were from different periods of spring. Soil moisture did not have any significant effect on GPP. A Dynamic Global Vegetation Model, a DGVM called LPJ-GUESS, was downscaled to the Simpevarp investigation area. The downscaled DGVM was evaluated against measured respiration and soil organic acids for all five ecosystems. In meadow, it was evaluated against Net Primary Production, NPP. For the forest ecosystems, it was evaluated against tree layer carbon pools. The evaluation indicated that the DGVM is reasonably well downscaled to the Simpevarp investigation area and

  2. Implications of Climate Change for Northern Canada: Freshwater, Marine, and Terrestrial Ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Prowse, Terry D.; Wrona, Fred J. (Water and Climate Impacts Research Centre, Environment Canada, Dept. of Geography, Univ. of Victoria, Victoria, BC (Canada)). e-mail: terry.prowse@ec.gc.caa; Furgal, Chris (Indigenous Environmental Studies Program, Trent Univ., Peterborough, ON (Canada)); Reist, James D. (Fisheries and Oceans Canada, 501 Univ. Crescent, Winnipeg, MB (Canada))

    2009-07-15

    Climate variability and change is projected to have significant effects on the physical, chemical, and biological components of northern Canadian marine, terrestrial, and freshwater systems. As the climate continues to change, there will be consequences for biodiversity shifts and for the ranges and distribution of many species with resulting effects on availability, accessibility, and quality of resources upon which human populations rely. This will have implications for the protection and management of wildlife, fish, and fisheries resources; protected areas; and forests. The northward migration of species and the disruption and competition from invading species are already occurring and will continue to affect marine, terrestrial, and freshwater communities. Shifting environmental conditions will likely introduce new animal-transmitted diseases and redistribute some existing diseases, affecting key economic resources and some human populations. Stress on populations of iconic wildlife species, such as the polar bear, ringed seals, and whales, will continue as a result of changes in critical sea-ice habitat interactions. Where these stresses affect economically and culturally important species, they will have significant effects on people and regional economies. Further integrated, field-based monitoring and research programs, and the development of predictive models are required to allow for more detailed and comprehensive projections of change to be made, and to inform the development and implementation of appropriate adaptation, wildlife, and habitat conservation and protection strategies

  3. Effect of climate warming on the annual terrestrial net ecosystem CO2 exchange globally in the boreal and temperate regions.

    Science.gov (United States)

    Zhang, Zhiyuan; Zhang, Renduo; Cescatti, Alessandro; Wohlfahrt, Georg; Buchmann, Nina; Zhu, Juan; Chen, Guanhong; Moyano, Fernando; Pumpanen, Jukka; Hirano, Takashi; Takagi, Kentaro; Merbold, Lutz

    2017-06-08

    The net ecosystem CO 2 exchange is the result of the imbalance between the assimilation process (gross primary production, GPP) and ecosystem respiration (RE). The aim of this study was to investigate temperature sensitivities of these processes and the effect of climate warming on the annual terrestrial net ecosystem CO 2 exchange globally in the boreal and temperate regions. A database of 403 site-years of ecosystem flux data at 101 sites in the world was collected and analyzed. Temperature sensitivities of rates of RE and GPP were quantified with Q 10 , defined as the increase of RE (or GPP) rates with a temperature rise of 10 °C. Results showed that on the annual time scale, the intrinsic temperature sensitivity of GPP (Q 10sG ) was higher than or equivalent to the intrinsic temperature sensitivity of RE (Q 10sR ). Q 10sG was negatively correlated to the mean annual temperature (MAT), whereas Q 10sR was independent of MAT. The analysis of the current temperature sensitivities and net ecosystem production suggested that temperature rise might enhance the CO 2 sink of terrestrial ecosystems both in the boreal and temperate regions. In addition, ecosystems in these regions with different plant functional types should sequester more CO 2 with climate warming.

  4. A lake classification concept for a more accurate global estimate of the dissolved inorganic carbon export from terrestrial ecosystems to inland waters

    Science.gov (United States)

    Engel, Fabian; Farrell, Kaitlin J.; McCullough, Ian M.; Scordo, Facundo; Denfeld, Blaize A.; Dugan, Hilary A.; de Eyto, Elvira; Hanson, Paul C.; McClure, Ryan P.; Nõges, Peeter; Nõges, Tiina; Ryder, Elizabeth; Weathers, Kathleen C.; Weyhenmeyer, Gesa A.

    2018-04-01

    The magnitude of lateral dissolved inorganic carbon (DIC) export from terrestrial ecosystems to inland waters strongly influences the estimate of the global terrestrial carbon dioxide (CO2) sink. At present, no reliable number of this export is available, and the few studies estimating the lateral DIC export assume that all lakes on Earth function similarly. However, lakes can function along a continuum from passive carbon transporters (passive open channels) to highly active carbon transformers with efficient in-lake CO2 production and loss. We developed and applied a conceptual model to demonstrate how the assumed function of lakes in carbon cycling can affect calculations of the global lateral DIC export from terrestrial ecosystems to inland waters. Using global data on in-lake CO2 production by mineralization as well as CO2 loss by emission, primary production, and carbonate precipitation in lakes, we estimated that the global lateral DIC export can lie within the range of {0.70}_{-0.31}^{+0.27} to {1.52}_{-0.90}^{+1.09} Pg C yr-1 depending on the assumed function of lakes. Thus, the considered lake function has a large effect on the calculated lateral DIC export from terrestrial ecosystems to inland waters. We conclude that more robust estimates of CO2 sinks and sources will require the classification of lakes into their predominant function. This functional lake classification concept becomes particularly important for the estimation of future CO2 sinks and sources, since in-lake carbon transformation is predicted to be altered with climate change.

  5. Effects of active forest fire on terrestrial ecosystem production and greenhouse gas emissions

    Science.gov (United States)

    Sannigrahi, Srikanta; Rahmat, Shahid; Bhatt, Sandeep; Rana, Virendra

    2017-04-01

    The forest fire is one of the most catalysing agents which degrade an ecosystems leading to the loss of net and gross primary productivity (NPP & GPP) and carbon sequestration service. Additionally, it can suppress the efficiency of service providing capacity of an ecosystem throughout the time and space. Remote sensing-based forest fire estimation in a diverse ecosystem is very much essential for mitigating the biodiversity and productivity losses due to the forest fire. Satellite-based Land Surface Temperature (LST) has been calculated for the pre-fire and fire years to identify the burn severity hotspot across all eco-regions in the Lower Himalaya region. Several burn severity indices: Normalized Burn Ratio (NBR), Burnt Area Index (BAI), Normalized Multiband Drought Index (NMDI), Soil Adjusted Vegetation Index (SAVI), Global Environmental Monitoring Index (GEMI), Enhance Vegetation Index (EVI) have been used in this study to quantify the spatial and temporal changes (delta) of the selected indices. Two Light Use Efficiency (LUE) models: Carnegie- Ames-Stanford-Approach (CASA) and Vegetation Photosynthesis Model (VPM) have been used to quantify the terrestrial Net Primary Productivity (NPP) in the pre-fire and fire years across all biomes of the region. A novel approach has been preceded in this field to demonstrate the correlation between forest fire density (FFD) and NPP. A strong positive correlation was found between burn severity indices and predicted NPP: BAI and NPP (r = 0.49), NBR and NPP: (r = 0.58), EVI and NPP: (r = 0.72), SAVI and NPP: (r = 0.67), whereas, a negative association has noted between the NMDI and NPP: (r = -0.36) during the both studied years. Results have shown that the NPP is highly correlated with the forest fire density (R2 = 0.75, RMSE = 5.03 gC m-2 month-1). The estimated LST of the individual fire days has witnessed a sharp temperature increase by > 6oC - 9oC in comparison to the non-fire days clearly indicates high fire risk (in

  6. Change in terrestrial ecosystem water-use efficiency over the last three decades.

    Science.gov (United States)

    Huang, Mengtian; Piao, Shilong; Sun, Yan; Ciais, Philippe; Cheng, Lei; Mao, Jiafu; Poulter, Ben; Shi, Xiaoying; Zeng, Zhenzhong; Wang, Yingping

    2015-06-01

    facilitate mechanistic understanding of the carbon-water interactions over terrestrial ecosystems under global change. © 2015 John Wiley & Sons Ltd.

  7. Hexabromocyclododecane affects benthic-pelagic coupling in an experimental ecosystem

    International Nuclear Information System (INIS)

    Bradshaw, Clare; Näslund, Johan; Hansen, Joakim; Kozlowsky-Suzuki, Betina; Sundström, Bo; Gustafsson, Kerstin

    2015-01-01

    Hexabromocyclododecane (HBCDD) is an additive brominated flame retardant and a recognized PBT chemical. However, little is known about its effects on coastal species, and even less on ecosystem effects. We investigated the dose–response effects of HBCDD over 8 months in 1000 L experimental mesocosms assembled from coastal Baltic Sea ecosystem components. HBCDD was added via spiked plankton material and a range of structural and functional endpoints were measured during the experiment. Increasing HBCDD concentration decreased the biomass of large Macoma balthica, resulting in a decreased recirculation of nutrients to the water. Changes in plankton communities were also observed, either due to direct toxic HBCDD effects or indirect via changes in benthic-pelagic coupling of nutrients. Such complex ecosystem responses can only be quantified and understood by using realistic experimental set-ups, and including knowledge of system-specific ecological interactions. This is the first study of HBCDD effects on ecosystem level. - Graphical abstract: HBCDD caused direct effects on the population structure of sediment-dwelling Macoma balthica and on the plankton community. Indirect HBCDD effects via reduced nutrient remineralization by M. balthica affected nutrient levels in the water, likely leading to additional changes in plankton community structure. Seasonal effects were large and affected the whole system including nutrient dynamics as well as plankton community structure. Display Omitted - Highlights: • HBCDD caused effects on benthic population structure and ecosystem function. • Large seasonal effects highlight the importance of using relevant experimental conditions. • A realistic exposure pathway was applied by using HBCDD enriched plankton material. • This is the first study of HBCDD effects on ecosystem level, coupling benthic and pelagic communities. - HBCDD has a dose-dependent effect on benthic-pelagic coupling.

  8. Enhanced water use efficiency in global terrestrial ecosystems under increasing aerosol loadings

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Xiaoliang; Chen, Min; Liu, Yaling; Miralles, Diego G.; Wang, Faming

    2017-05-01

    Aerosols play a crucial role in the climate system, affecting incoming radiation and cloud formation. Based on a modelling framework that couples ecosystem processes with the atmospheric transfer of radiation, we analyze the effect of aerosols on surface incoming radiation, gross primary productivity (GPP), water losses from ecosystems through evapotranspiration (ET) and ecosystem water use efficiency (WUE, defined as GPP/ET) for 2003–2010 and validate them at global FLUXNET sites. The total diffuse radiation increases under relatively low or intermediate aerosol loadings, but decreases under more polluted conditions. We find that aerosol-induced changes in GPP depend on leaf area index, aerosol loading and cloudiness. Specifically, low and moderate aerosol loadings cause increases in GPP for all plant types, while heavy aerosol loadings result in enhancement (decrease) in GPP for dense (sparse) vegetation. On the other hand, ET is mainly negatively affected by aerosol loadings due to the reduction in total incoming radiation. Finally, WUE shows a consistent rise in all plant types under increasing aerosol loadings. Overall, the simulated daily WUE compares well with observations at 43 eddy-covariance tower sites (R2=0.84 and RMSE=0.01gC (kg H2O)-1) with better performance at forest sites. In addition to the increasing portions of diffuse light, the rise in WUE is also favored by the reduction in radiation- and heat-stress caused by the aerosols, especially for wet and hot climates.

  9. Reed beds may facilitate transfer of tributyltin from aquatic to terrestrial ecosystems through insect vectors in the Archipelago Sea, SW Finland.

    Science.gov (United States)

    Lilley, Thomas M; Meierjohann, Axel; Ruokolainen, Lasse; Peltonen, Jani; Vesterinen, Eero; Kronberg, Leif; Nikinmaa, Mikko

    2012-08-01

    Due to their adsorptive behavior, organotin compounds (OTCs), such as tributyltin (TBT), are accumulated in aquatic sediments. They resist biodegradation and, despite a ban in 2008, are a potential source for future exposure. Sediment OTCs have mostly been measured from sites of known high concentrations such as ports, shipping lanes, and marine dredging waste sites. The possible flow of OTCs from marine to terrestrial ecosystems, however, has not been studied. In the present study, the authors assessed whether sediments in common reed beds (Phragmites australis) accumulate TBT and whether chironomid (Diptera: Chironomidae) communities developing in reed-bed sediments act as vectors in the transfer of TBT from aquatic to terrestrial ecosystems in the Airisto channel, Archipelago Sea. The authors also investigated whether distance from the only known source and depth and TBT concentration of the adjacent shipping lane affect reed-bed concentrations. Thirty-six sites along the Airisto channel were sampled at 2-km intervals with triplicate samples from reed beds and the adjacent shipping lane for sediment and seven reed-bed sites for chironomids, and these were analyzed with an solid phase extraction liquid chromatography tamdem mass spectrometry method. The closer to the source the sample site was, the higher the measured TBT concentrations were; and the deeper the shipping lane, the lower the concentration of TBT in reed-bed sediments. The chironomid TBT concentrations correlated with reed-bed sediment TBT concentrations and showed evidence of accumulation. Therefore, TBT may be transferred, through the food web, from aquatic to terrestrial ecosystems relatively close to a source through ecosystem boundaries, such as common reed beds, which are areas of high insect biomass production in the Archipelago Sea. Copyright © 2012 SETAC.

  10. Improving the Characterization of Arctic Coastline Ecosystem Change near Utqiagvik, Alaska Utilizing Multiyear Terrestrial Laser Scanning

    Science.gov (United States)

    Escarzaga, S. M.; Cody, R. P.; Vargas, S. A., Jr.; Fuson, T.; Hodge, B. E.; Tweedie, C. E.

    2017-12-01

    The Arctic Ocean comprises the largest coastline on Earth and is undergoing environmental change on a level disproportionate to those in lower-latitudes. In the US Arctic, coastal erosion rates along the North Slope of Alaska show that they are among highest in the nation at an average rate of 1.4 meters per year. Despite their importance to biogeochemical cycling, Native village infrastructure and providing pristine species habitat, Arctic coastlines and near shore environments are relatively understudied due to logistical challenges of conducting fieldwork in these locations. This study expands on past efforts which showed dGPS foot surveys work well at describing planar erosion on less complex permafrost bluff types like those seen on the higher-energy coasts east of Utqiagvik, Alaska along the Beaufort Sea where the main mechanism of erosion happens by block failure caused by wave action. However, coastal bluffs along the Chukchi Sea to the west are more complex and variable in terms of form and mechanisms of erosion. Here, where wide beaches tend to buffer wave action, thermal erosion and permafrost slumping produce slower erosion rates. Terrestrial Laser Scanning (TLS) has been applied across a multitude of terrain types, including coastlines spanning various ecosystems. Additionally, this approach allows 3D modeling of fine scale geomorphological features which can facilitate modeling of erosion rates in these areas. This study utilizes a six year time series of TLS on a section of coastal permafrost bluff along the Chukchi Sea south of Utqiagvik. The aim of the work presented is to better understand spatio-temporal trends of coastal bluff face erosion, bluff top subsidence and how these landscape microtopographic changes are coupled to ecosystem changes and land cover types. Preliminary analysis suggests a high rate of stability of the bluff face over the TLS record with most of the detectable permafrost subsidence happening closer to the coastal bluff edge.

  11. A new Cretaceous terrestrial ecosystem from Gondwana with the description of a new sauropod dinosaur

    Directory of Open Access Journals (Sweden)

    Jorge O. Calvo

    2007-09-01

    Full Text Available A unique site at the northern area of Patagonia (Neuquén, Argentina reveals a terrestrial ecosystem preserved in a detail never reported before in a Late Cretaceous deposit. An extraordinary diversity and abundance of fossils was found concentrated in a 0.5 m horizon in the same quarry, including a new titanosaur sauropod, Futalognkosaurus dukei n.gen., n.sp, which is the most complete giant dinosaur known so far. Several plant leaves, showing a predominance of angiosperms over gymnosperms that likely constituted the diet of F. dukei were found too. Other dinosaurs (sauropods, theropods, ornithopods, crocodylomorphs, pterosaurs, and fishes were also discovered, allowing a partial reconstruction of this Gondwanan continental ecosystem.Um depósito fóssil na região norte da Patagônia (Neuquén, Argentina revela um ecossistema nunca antes registrado a este nível de detalhes em depósitos do Cretáceo Superior. Uma diversidade e abundância extraordinária de fósseis encontra-se concentrada em uma camada de 0,5 m no mesmo sítio, incluindo um novo saurópodo titanossaurídeo, Futalognkosaurus dukei n. gen, n. sp., que é o mais completo dinossauro gigante encontrado até a presente data. Foram descobertas váriasfolhas de plantas indicando a predominância de angiospermas sobre gimnospermas que possivelmente formavam a base da dieta de F. dukei. Outros dinossauros (saurópodes, terópodes, ornitópodes, crocodilomorfos, pterossauros e peixes foram também encontrados possibilitando a reconstrução parcialdeste ecossistema continental do Gondwana.

  12. Experimental terrestrial soil-core microcosm test protocol. A method for measuring the potential ecological effects, fate, and transport of chemicals in terrestrial ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Van Voris, P.; Tolle, D.A.; Arthur, M.F.

    1985-06-01

    In order to protect the environment properly and have a realistic appraisal of how a chemical will act in the environment, tests of ecological effects and chemical fate must be performed on complex assemblages of biotic and abiotic components (i.e., microcosms) as well as single species. This protocol is one which could be added to a series of tests recently developed as guidelines for Section 4 of the Toxic Substances Control Act (P.L. 94-469; U.S.C., Section 2601-2629). The terrestrial soil-core microcosm is designed to supply site-specific and possibly regional information on the probable chemical fate and ecological effects resulting from release of a chemical substance to a terrestrial ecosystem. The EPA will use the data resulting from this test system to compare the potential hazards of a chemical with others that have been previously evaluated.

  13. Terrestrial Carbon Sinks in the Brazilian Amazon and Cerrado Region Predicted from MODIS Satellite Data and Ecosystem Modeling

    Science.gov (United States)

    Potter, C.; Klooster, S.; Huete, A.; Genovese, V.; Bustamante, M.; Ferreira, L. Guimaraes; deOliveira, R. C., Jr.; Zepp, R.

    2009-01-01

    A simulation model based on satellite observations of monthly vegetation cover from the Moderate Resolution Imaging Spectroradiometer (MODIS) was used to estimate monthly carbon fluxes in terrestrial ecosystems of Brazilian Amazon and Cerrado regions over the period 2000-2004. Net ecosystem production (NEP) flux for atmospheric CO2 in the region for these years was estimated. Consistently high carbon sink fluxes in terrestrial ecosystems on a yearly basis were found in the western portions of the states of Acre and Rondonia and the northern portions of the state of Par a. These areas were not significantly impacted by the 2002-2003 El Nino event in terms of net annual carbon gains. Areas of the region that show periodically high carbon source fluxes from terrestrial ecosystems to the atmosphere on yearly basis were found throughout the state of Maranhao and the southern portions of the state of Amazonas. As demonstrated though tower site comparisons, NEP modeled with monthly MODIS Enhanced Vegetation Index (EVI) inputs closely resembles the measured seasonal carbon fluxes at the LBA Tapajos tower site. Modeling results suggest that the capacity for use of MODIS Enhanced Vegetation Index (EVI) data to predict seasonal uptake rates of CO2 in Amazon forests and Cerrado woodlands is strong.

  14. Shifts of community composition and population density substantially affect ecosystem function despite invariant richness

    NARCIS (Netherlands)

    Spaak, Jurg W.; Baert, Jan M.; Baird, Donald J.; Eisenhauer, Nico; Maltby, Lorraine; Pomati, Francesco; Radchuk, Viktoriia; Rohr, Jason R.; Brink, van den Paul J.; Laender, De Frederik

    2017-01-01

    There has been considerable focus on the impacts of environmental change on ecosystem function arising from changes in species richness. However, environmental change may affect ecosystem function without affecting richness, most notably by affecting population densities and community

  15. An evaluation of the ecological and environmental security on China's terrestrial ecosystems.

    Science.gov (United States)

    Zhang, Hongqi; Xu, Erqi

    2017-04-11

    With rapid economic growth, industrialization, and urbanization, various ecological and environmental problems occur, which threaten and undermine the sustainable development and domestic survival of China. On the national scale, our progress remains in a state of qualitative or semi-quantitative evaluation, lacking a quantitative evaluation and a spatial visualization of ecological and environmental security. This study collected 14 indictors of water, land, air, and biodiversity securities to compile a spatial evaluation of ecological and environmental security in terrestrial ecosystems of China. With area-weighted normalization and scaling transformations, the veto aggregation (focusing on the limit indicator) and balanced aggregation (measuring balanced performance among different indicators) methods were used to aggregate security evaluation indicators. Results showed that water, land, air, and biodiversity securities presented different spatial distributions. A relatively serious ecological and environmental security crisis was found in China, but presented an obviously spatial variation of security evaluation scores. Hotspot areas at the danger level, which are scattered throughout the entirety of the country, were identified. The spatial diversities and causes of ecological and environmental problems in different regions were analyzed. Spatial integration of regional development and proposals for improving the ecological and environmental security were put forward.

  16. Levels and transfer of 210Po and 210Pb in Nordic terrestrial ecosystems

    International Nuclear Information System (INIS)

    Brown, J.E.; Gjelsvik, R.; Roos, P.; Kalas, J.A.; Outola, I.; Holm, E.

    2011-01-01

    Recent developments regarding environmental impact assessment methodologies for radioactivity have precipitated the need for information on levels of naturally occurring radionuclides within and transfer to wild flora and fauna. The objectives of this study were therefore to determine activity concentrations of the main dose forming radionuclides 210 Po and 210 Pb in biota from terrestrial ecosystems thus providing insight into the behaviour of these radioisotopes. Samples of soil, plants and animals were collected at Dovrefjell, Central Norway and Olkiluoto, Finland. Soil profiles from Dovrefjell exhibited an approximately exponential fall in 210 Pb activity concentrations from elevated levels in humus/surface soils to 'supported' levels at depth. Activity concentrations of 210 Po in fauna (invertebrates, mammals, birds) ranged between 2 and 123 Bq kg -1 d.w. and in plants and lichens between 20 and 138 Bq kg -1 d.w. The results showed that soil humus is an important reservoir for 210 Po and 210 Pb and that fauna in close contact with this media may also exhibit elevated levels of 210 Po. Concentration ratios appear to have limited applicability with regards to prediction of activity concentrations of 210 Po in invertebrates and vertebrates. Biokinetic models may provide a tool to explore in a more mechanistic way the behaviour of 210 Po in this system.

  17. Levels and transfer of {sup 210}Po and {sup 210}Pb in Nordic terrestrial ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Brown, J.E., E-mail: justin.brown@nrpa.n [Norwegian Radiation Protection Authority, PO Box 55, N-1332, Osteras (Norway); Gjelsvik, R. [Norwegian Radiation Protection Authority, PO Box 55, N-1332, Osteras (Norway); Roos, P. [RISO-DTU P.O. Box 49 DK-4000 Roskilde (Denmark); Kalas, J.A. [Norwegian Institute for Nature Research (NINA), Tungasletta 2, 7485 Trondheim (Norway); Outola, I. [STUK, Laippatie 4/P.O. BOX 14, 00881 Helsinki (Finland); Holm, E. [Norwegian Radiation Protection Authority, PO Box 55, N-1332, Osteras (Norway)

    2011-05-15

    Recent developments regarding environmental impact assessment methodologies for radioactivity have precipitated the need for information on levels of naturally occurring radionuclides within and transfer to wild flora and fauna. The objectives of this study were therefore to determine activity concentrations of the main dose forming radionuclides {sup 210}Po and {sup 210}Pb in biota from terrestrial ecosystems thus providing insight into the behaviour of these radioisotopes. Samples of soil, plants and animals were collected at Dovrefjell, Central Norway and Olkiluoto, Finland. Soil profiles from Dovrefjell exhibited an approximately exponential fall in {sup 210}Pb activity concentrations from elevated levels in humus/surface soils to 'supported' levels at depth. Activity concentrations of {sup 210}Po in fauna (invertebrates, mammals, birds) ranged between 2 and 123 Bq kg{sup -1} d.w. and in plants and lichens between 20 and 138 Bq kg{sup -1} d.w. The results showed that soil humus is an important reservoir for {sup 210}Po and {sup 210}Pb and that fauna in close contact with this media may also exhibit elevated levels of {sup 210}Po. Concentration ratios appear to have limited applicability with regards to prediction of activity concentrations of {sup 210}Po in invertebrates and vertebrates. Biokinetic models may provide a tool to explore in a more mechanistic way the behaviour of {sup 210}Po in this system.

  18. Fogwater deposition modeling for terrestrial ecosystems: A review of developments and measurements

    Science.gov (United States)

    Katata, Genki

    2014-07-01

    Recent progress in modeling fogwater (and low cloud water) deposition over terrestrial ecosystems during fogwater droplet interception by vegetative surfaces is reviewed. Several types of models and parameterizations for fogwater deposition are discussed with comparing assumptions, input parameter requirements, and modeled processes. The relationships among deposition velocity of fogwater (Vd) in model results, wind speed, and plant species structures associated with literature values are gathered for model validation. Quantitative comparisons between model results and observations in forest environments revealed differences as large as 2 orders of magnitude, which are likely caused by uncertainties in measurement techniques over heterogeneous landscapes. Results from the literature review show that Vd values ranged from 2.1 to 8.0 cm s-1 for short vegetation, whereas Vd = 7.7-92 cm s-1 and 0-20 cm s-1 for forests measured by throughfall-based methods and the eddy covariance method, respectively. This review also discusses the current understanding of the impacts of fogwater deposition on atmosphere-land interactions and over complex terrain based on results from numerical studies. Lastly, future research priorities in innovative modeling and observational approaches for model validation are outlined.

  19. Global Monthly CO2 Flux Inversion Based on Results of Terrestrial Ecosystem Modeling

    Science.gov (United States)

    Deng, F.; Chen, J.; Peters, W.; Krol, M.

    2008-12-01

    Most of our understanding of the sources and sinks of atmospheric CO2 has come from inverse studies of atmospheric CO2 concentration measurements. However, the number of currently available observation stations and our ability to simulate the diurnal planetary boundary layer evolution over continental regions essentially limit the number of regions that can be reliably inverted globally, especially over continental areas. In order to overcome these restrictions, a nested inverse modeling system was developed based on the Bayesian principle for estimating carbon fluxes of 30 regions in North America and 20 regions for the rest of the globe. Inverse modeling was conducted in monthly steps using CO2 concentration measurements of 5 years (2000 - 2005) with the following two models: (a) An atmospheric transport model (TM5) is used to generate the transport matrix where the diurnal variation n of atmospheric CO2 concentration is considered to enhance the use of the afternoon-hour average CO2 concentration measurements over the continental sites. (b) A process-based terrestrial ecosystem model (BEPS) is used to produce hourly step carbon fluxes, which could minimize the limitation due to our inability to solve the inverse problem in a high resolution, as the background of our inversion. We will present our recent results achieved through a combination of the bottom-up modeling with BEPS and the top-down modeling based on TM5 driven by offline meteorological fields generated by the European Centre for Medium Range Weather Forecast (ECMFW).

  20. Predicting ecosystem dynamics at regional scales: an evaluation of a terrestrial biosphere model for the forests of northeastern North America.

    Science.gov (United States)

    Medvigy, David; Moorcroft, Paul R

    2012-01-19

    Terrestrial biosphere models are important tools for diagnosing both the current state of the terrestrial carbon cycle and forecasting terrestrial ecosystem responses to global change. While there are a number of ongoing assessments of the short-term predictive capabilities of terrestrial biosphere models using flux-tower measurements, to date there have been relatively few assessments of their ability to predict longer term, decadal-scale biomass dynamics. Here, we present the results of a regional-scale evaluation of the Ecosystem Demography version 2 (ED2)-structured terrestrial biosphere model, evaluating the model's predictions against forest inventory measurements for the northeast USA and Quebec from 1985 to 1995. Simulations were conducted using a default parametrization, which used parameter values from the literature, and a constrained model parametrization, which had been developed by constraining the model's predictions against 2 years of measurements from a single site, Harvard Forest (42.5° N, 72.1° W). The analysis shows that the constrained model parametrization offered marked improvements over the default model formulation, capturing large-scale variation in patterns of biomass dynamics despite marked differences in climate forcing, land-use history and species-composition across the region. These results imply that data-constrained parametrizations of structured biosphere models such as ED2 can be successfully used for regional-scale ecosystem prediction and forecasting. We also assess the model's ability to capture sub-grid scale heterogeneity in the dynamics of biomass growth and mortality of different sizes and types of trees, and then discuss the implications of these analyses for further reducing the remaining biases in the model's predictions.

  1. [Characteristics of terrestrial ecosystem primary productivity in East Asia based on remote sensing and process-based model].

    Science.gov (United States)

    Zhang, Fang-Min; Ju, Wei-Min; Chen, Jing-Ming; Wang, Shao-Qiang; Yu, Gui-Rui; Han, Shi-Jie

    2012-02-01

    Based on the bi-linearly interpolated meteorological reanalysis data from National Centers for Environmental Prediction, USA and by using the leaf area index data derived from the GIMMS NDVI to run the process-based Boreal Ecosystems Productivity Simulator (BEPS) model, this paper simulated and analyzed the spatiotemporal characteristics of the terrestrial ecosystem gross primary productivity (GPP) and net primary productivity (NPP) in East Asia in 2000-2005. Before regional simulating and calculating, the observation GPP data of different terrestrial ecosystem in 15 experimental stations of AsiaFlux network and the inventory measurements of NPP at 1300 sampling sites were applied to validate the BEPS GPP and NPP. The results showed that BEPS could well simulate the changes in GPP and NPP of different terrestrial ecosystems, with the R2 ranging from 0.86 to 0.99 and the root mean square error (RMSE) from 0.2 to 1.2 g C x m(-2) x d(-1). The simulated values by BEPS could explain 78% of the changes in annual NPP, and the RMSE was 118 g C x m(-2) x a(-1). In 2000-2005, the averaged total GPP and total NPP of the terrestrial ecosystems in East Asia were 21.7 and 10.5 Pg C x a(-1), respectively, and the GPP and NPP exhibited similar spatial and temporal variation patterns. During the six years, the total NPP of the terrestrial ecosystems varied from 10.2 to 10.7 Pg C x a(-1), with a coefficient of variation being 2. 2%. High NPP (above 1000 g C x m(-2) x a(-1)) occurred in the southeast island countries, while low NPP (below 30 g C x m(-2) x a(-1)) occurred in the desert area of Northwest China. The spatial patterns of NPP were mainly attributed to the differences in the climatic variables across East Asia. The NPP per capita also varied greatly among different countries, which was the highest (70217 kg C x a(-1)) in Mongolia, far higher than that (1921 kg C x a(-1)) in China, and the lowest (757 kg C x a(-1)) in India.

  2. Intercomparison of Terrestrial Laser Scanning Instruments for Assessing Forested Ecosystems: A Brisbane Field Experiment

    Science.gov (United States)

    Armston, J.; Newnham, G.; Strahler, A. H.; Schaaf, C.; Danson, M.; Gaulton, R.; Zhang, Z.; Disney, M.; Sparrow, B.; Phinn, S. R.; Schaefer, M.; Burt, A.; Counter, S.; Erb, A.; Goodwin, N.; Hancock, S.; Howe, G.; Johansen, K.; Li, Z.; Lollback, G.; Martel, J.; Muir, J.; Paynter, I.; Saenz, E.; Scarth, P.; Tindall, D.; Walker, L.; Witte, C.; Woodgate, W.; Wu, S.

    2013-12-01

    During 28th July - 3rd August, 2013, an international group of researchers brought five terrestrial laser scanners (TLS) to long-term monitoring plots in three eucalyptus-dominated woodland sites near Brisbane, Queensland, Australia, to acquire scans at common locations for calibration and intercomparison.They included: DWEL - a dual-wavelength full-waveform laser scanner (Boston U., U. Massachusetts Lowell, U. Massachusetts Boston, USA) SALCA - a dual-wavelength full-waveform laser scanner (U. Salford, UK) CBL - a canopy biomass lidar, a small ultraportable low-cost multiple discrete return scanner (U. Massachusetts Boston, USA) Riegl VZ400 - a survey-grade commercial waveform scanner (Queensland Government and TERN, U. Queensland, Australia) FARO Focus 3D - a lightweight commercial phase-shift ranging laser scanner (U. Southern Queensland) Two plots were scanned at Karawatha Forest Park, a Terrestrial Ecosystem Research Network (TERN) Supersite, and one plot at D'Aguilar National Park. At each 50 x 100 m plot, a center scan point was surrounded by four scan points located 25 m away in a cross pattern allowing for 3-D reconstructions of scan sites in the form of point clouds. At several center points, multiple instrument configurations (i.e. different beam divergence, angular resolution, pulse rate) were acquired to test the impact of instrument specifications on separation of woody and non-woody materials and estimation of vegetation structure parameters. Three-dimensional Photopoint photographic panoramas were also acquired, providing reconstructions of stems in the form of point clouds using photogrammetric correlation methods. Calibrated reflectance targets were also scanned to compare instrument geometric and radiometric performance. Ancillary data included hemispherical photos, TRAC LAI/clumping measurements, spectra of leaves, bark, litter, and other target components. Wet and dry leaf weights determined water content. Planned intercomparison topics and

  3. Terrestrial ecosystem collapse associated to the K-Pg boundary and dinosaur extinction: palynological evidences

    Science.gov (United States)

    Bercovici, A.; Vajda, V.; Lyson, T. R.; Chester, S. G. B.; Sargis, E. J.; Pearson, D. A.; Joyce, W. G.

    2012-04-01

    We report here the discovery of the stratigraphically youngest in situ dinosaur specimen. This ceratopsian brow horn was found in southeastern Montana, in the Western Interior of the United States in a poorly rooted, silty mudstone floodplain deposit and only 13 centimeters below the palynologically defined K-Pg boundary. The boundary is identified using three criteria: 1) substantial decrease in diversity and abundance of Cretaceous pollen and spore taxa that completely disappear from the palynological record a few meters above the boundary, 2) the presence of a "fern spike", and 3) palynostratigraphical correlation to a nearby section where primary extraterrestrial impact markers are present (e.g., iridium anomaly, spherules and shocked quartz). The palynological record in the rock sequence immediately following the K-Pg boundary consistently indicates a sudden and major loss of the Cretaceous components across the North American record. During this rapid decline, the palynological assemblages are dominated by freshwater ferns (Azolla) and algae (usually Pediastrum sp. and Penetetrapites sp.) indicating generalized flooding in the area. The onset of the Paleocene sedimentation is subsequently announced by the presence of variegated beds, multiple lignite seams and small scale meandering river systems, starting with palynological associations that attest for reworking and erosion. The destabilization of terrestrial ecosystems is coincident with the markers of the K-Pg boundary, supporting a catastrophic event taking place over a very short duration. The in situ ceratopsian brow horn demonstrates that a gap devoid of non-avian dinosaur fossils in the last meters of the Cretaceous is artificial and thus inconsistent with the hypothesis that non-avian dinosaurs were extinct prior to the K-Pg boundary asteroid impact event.

  4. The spatiotemporal variation in evapotranspiration of terrestrial ecosystems in China between 1982-2015

    Science.gov (United States)

    Lian, X.; Piao, S.; Li, X.

    2017-12-01

    Evapotranspiration (ET) is one of the most important fluxes in the terrestrial ecosystem, and play a vital role in regulating atmosphere-hydrosphere-biosphere interaction. Several studies have suggested that global ET has significantly increased in the past several decades, and that such increase has exhibited big spatial variability, but there are few detailed studies on the spatio-temporal change in ET over China. Combining remote-sensing and ground-based observations with a machine learning approach (model tree ensemble, MTE), this study investigate the spatiotemporal variation in ET in China during 1982 and 2015. Our results showed that mean annual ET in China is 552±14mm year-1, which is within range of estimates by previous studies (from 430 mm year-1 to 555 mm year-1). ET spatially decreases from southeast to northwest, with highest value appeared in humidity regions (more than 1400 mm year-1) and lowest value in arid regions (less than 200 mm year-1). Over the past three decades, ET in China significantly increased by 1.07 mm year-2 with remarkable spatial heterogeneity. The largest increase in ET appears in the eastern periphery of SiChuan Basin, which may be related to increase in temperature, solar radiation as well as enhancing vegetation productivity. Only 20% of study area show decrease in ET, which is mainly located in parts of the southeast, southwest and northeast of China. The regional decrease in ET is likely to be contributed by decrease in solar radiation and relative humidity. Although our finding of the significant increase in China's ET at the country scale is supported by five different ET products, there are still less agreement on the change in ET at the regional scale among different ET products.

  5. Radiological bioconcentration factors for aquatic, terrestrial, and wetland ecosystems at the Savannah River Site

    International Nuclear Information System (INIS)

    Cummins, C.L.

    1994-09-01

    As a result of operations at the Savannah River Site (SRS), over 50 radionuclides have been released to the atmosphere and to onsite streams and seepage basins. Now, many of these radionuclides are available to aquatic and/or terrestrial organisms for uptake and cycling through the food chain. Knowledge about the uptake and cycling of these radionuclides is now crucial in evaluating waste management and clean-up alternatives for the site. Numerous studies have been conducted at the SRS over the past forty years to study the uptake and distribution of radionuclides in the Savannah River Site environment. In many instances, bioconcentration factors have been calculated to quantify the uptake of a radionuclide by an organism from the surrounding medium (i.e., soil or water). In the past, it has been common practice to use bioconcentration factors from the literature because site-specific data were not readily available. However, because of the variability of bioconcentration factors due to experimental or environmental conditions, site-specific data should be used when available. This report compiles and summarizes site-specific bioconcentration factors for selected radionuclides released at the Savannah River Site (SRS). An extensive literature search yielded site-specific bioconcentration factors for cesium, strontium, cobalt, plutonium, americium, curium, and tritium. These eight radionuclides have been the primary radionuclides studied at SRS because of their long half lives or because they are major contributors to radiological dose from exposure. For most radionuclides, it was determined that the site-specific bioconcentration factors were higher than those reported in literature. This report also summarizes some conditions that affect radionuclide bioavailability to and bioconcentration by aquatic and terrestrial organisms

  6. The role of UV-B radiation in aquatic and terrestrial ecosystems - an experimental and functional analysis of the evolution of UV-absorbing componist.

    NARCIS (Netherlands)

    Rozema, J.; Bjorn, L.O.; Bornman, J.F.; Gaberscik, A.; Hader, D.P.; Trost, T.; Germ, M.; Klisch, M.; Groniger, A.; Sinha, R.P.; Lebert, M.; He, Y.Y.; Buffoni-Hall, R.; Bakker, N.; van de Staaij, J.W.M.; Meijkamp, B.B.

    2002-01-01

    We analysed and compared the functioning of UV-B screening pigments in plants from marine, fresh water and terrestrial ecosystems, along the evolutionary line of cyanobacteria, unicellular algae, primitive multicellular algae, charophycean algae, lichens, mosses and higher plants, including

  7. Exploring industry specific social welfare maximizing rates of water pollution abatement in linked terrestrial and marine ecosystems

    NARCIS (Netherlands)

    Roebeling, P.C.; Hendrix, E.M.T.; Grieken, van M.E.

    2009-01-01

    Marine ecosystems are severely affected by water pollution originating from coastal catchments, while these ecosystems are of vital importance from an environmental as well as an economic perspective. To warrant sustainable economic development of coastal regions, we need to balance the marginal

  8. Isotopic tracers for net primary productivity for a terrestrial ecosystem: a case study of the Volta River basin

    International Nuclear Information System (INIS)

    Hayford, E.K.; Odamtten, G.T.; Enu-Kwesi, L.

    2006-01-01

    The coupling effect of vapour release and CO2 uptake during photosynthesis plays an important role in the carbon and hydrologic cycles. The water use efficiency (WUE) for transpiration was used in calculating the net primary productivity (NPP) for terrestrial ecosystem. Three parameters were used in calculating the water and carbon balance of the River Volta watershed. These are 1) stable isotopes of hydrogen and oxygen, 2) long-term data on precipitation and evapotranspiration, and 3) stoichiometric relations of water and carbon. Results indicate that soils in the watershed annually respire 0.199 Pg C, and that the NPP is +0.029 Pg C yr-1. This implies an annual change in CO2 to the atmosphere within the watershed. Annually, River Volta watershed receives about 380 km3 of rainfall; approximately 50 per cent of which is returned to the atmosphere through plant transpiration. Associated with annual transpiration flux is a carbon flux of 0.170 x 1015 g C yr-1 or 428 g C m-2 yr-1 from the terrestrial ecosystem. Modeled estimates of heterotrophic soil respiration exceeds slightly the estimated NPP values, implying that carbon flux to and from the Volta river watershed is close to being in balance. In other words, the watershed releases annually more carbon dioxide to the atmosphere than it takes. Apart from the terrestrial carbon flux, the balance of photosynthesis and respiration in the Volta lake was also examined. The lake was found to release carbon dioxide to the atmosphere although the magnitude of the flux is smaller than that of the terrestrial ecosystem. (au)

  9. Modeling coupled interactions of carbon, water, and ozone exchange between terrestrial ecosystems and the atmosphere. I: Model description

    International Nuclear Information System (INIS)

    Nikolov, Ned; Zeller, Karl F.

    2003-01-01

    A new biophysical model (FORFLUX) is presented to link ozone deposition with carbon and water cycles in terrestrial ecosystems. - A new biophysical model (FORFLUX) is presented to study the simultaneous exchange of ozone, carbon dioxide, and water vapor between terrestrial ecosystems and the atmosphere. The model mechanistically couples all major processes controlling ecosystem flows trace gases and water implementing recent concepts in plant eco-physiology, micrometeorology, and soil hydrology. FORFLUX consists of four interconnected modules-a leaf photosynthesis model, a canopy flux model, a soil heat-, water- and CO 2 - transport model, and a snow pack model. Photosynthesis, water-vapor flux and ozone uptake at the leaf level are computed by the LEAFC3 sub-model. The canopy module scales leaf responses to a stand level by numerical integration of the LEAFC3 model over canopy leaf area index (LAI). The integration takes into account (1) radiative transfer inside the canopy, (2) variation of foliage photosynthetic capacity with canopy depth, (3) wind speed attenuation throughout the canopy, and (4) rainfall interception by foliage elements. The soil module uses principles of the diffusion theory to predict temperature and moisture dynamics within the soil column, evaporation, and CO 2 efflux from soil. The effect of soil heterogeneity on field-scale fluxes is simulated employing the Bresler-Dagan stochastic concept. The accumulation and melt of snow on the ground is predicted using an explicit energy balance approach. Ozone deposition is modeled as a sum of three fluxes- ozone uptake via plant stomata, deposition to non-transpiring plant surfaces, and ozone flux into the ground. All biophysical interactions are computed hourly while model projections are made at either hourly or daily time step. FORFLUX represents a comprehensive approach to studying ozone deposition and its link to carbon and water cycles in terrestrial ecosystems

  10. Removal of terrestrial DOC in aquatic ecosystems of a temperate river network

    Science.gov (United States)

    Wollheim, W.M.; Stewart, R. J.; Aiken, George R.; Butler, Kenna D.; Morse, Nathaniel B.; Salisbury, J.

    2015-01-01

    Surface waters play a potentially important role in the global carbon balance. Dissolved organic carbon (DOC) fluxes are a major transfer of terrestrial carbon to river systems, and the fate of DOC in aquatic systems is poorly constrained. We used a unique combination of spatially distributed sampling of three DOC fractions throughout a river network and modeling to quantify the net removal of terrestrial DOC during a summer base flow period. We found that aquatic reactivity of terrestrial DOC leading to net loss is low, closer to conservative chloride than to reactive nitrogen. Net removal occurred mainly from the hydrophobic organic acid fraction, while hydrophilic and transphilic acids showed no net change, indicating that partitioning of bulk DOC into different fractions is critical for understanding terrestrial DOC removal. These findings suggest that river systems may have only a modest ability to alter the amounts of terrestrial DOC delivered to coastal zones.

  11. Information indices as a tool for quantifying development of below-ground terrestrial ecosystems

    NARCIS (Netherlands)

    Holtkamp, R.; Tobor-Kaplon, M.A.

    2007-01-01

    Information indices from ecosystem network analysis (ENA) describe the size and organization of an ecosystem and are claimed to quantify ecosystem development [Ulanowicz, R.E., 1986, Growth and Development, Springler-Verslag, New York, 203 pp.]. To date, these indices were not used to describe a

  12. Dynamics of dissolved organic matter in fjord ecosystems: Contributions of terrestrial dissolved organic matter in the deep layer

    Science.gov (United States)

    Yamashita, Youhei; McCallister, S. Leigh; Koch, Boris P.; Gonsior, Michael; Jaffé, Rudolf

    2015-06-01

    Annually, rivers and inland water systems deliver a significant amount of terrestrial organic matter (OM) to the adjacent coastal ocean in both particulate and dissolved forms; however, the metabolic and biogeochemical transformations of OM during its seaward transport remains one of the least understood components of the global carbon cycle. This transfer of terrestrial carbon to marine ecosystems is crucial in maintaining trophic dynamics in coastal areas and critical in global carbon cycling. Although coastal regions have been proposed as important sinks for exported terrestrial materials, most of the global carbon cycling data, have not included fjords in their budgets. Here we present distributional patterns on the quantity and quality of dissolved OM in Fiordland National Park, New Zealand. Specifically, we describe carbon dynamics under diverse environmental settings based on dissolved organic carbon (DOC) depth profiles, oxygen concentrations, optical properties (fluorescence) and stable carbon isotopes. We illustrate a distinct change in the character of DOC in deep waters compared to surface and mid-depth waters. Our results suggest that, both, microbial reworking of terrestrially derived plant detritus and subsequent desorption of DOC from its particulate counterpart (as verified in a desorption experiment) are the main sources of the humic-like enriched DOC in the deep basins of the studied fjords. While it has been suggested that short transit times and protection of OM by mineral sorption may ultimately result in significant terrestrial carbon burial and preservation in fjords, our data suggests the existence of an additional source of terrestrial OM in the form of DOC generated in deep, fjord water.

  13. Scale dependence of absorption of photosynthetically active radiation in terrestrial ecosystems

    International Nuclear Information System (INIS)

    Asner, G.P.; Wessman, C.A.; Archer, S.

    1998-01-01

    The fraction of photosynthetically active radiation absorbed by plant canopies (fAPAR) is a critical biophysical variable for extrapolating ecophysiological measurements from the leaf to landscape scale. Quantification of fAPAR determinants at the landscape level is needed to improve the interpretation of remote sensing data, to facilitate its use in constraining ecosystem process models, and to improve synoptic-scale links between carbon and nutrient cycles. Most canopy radiation budget studies have focused on light attenuation in plant canopies, with little regard for the importance of the scale-dependent biophysical and structural factors (e.g., leaf and stem optical properties, leaf and stem area, and extent of vegetation structural types) that ultimately determine fAPAR at canopy and landscape scales. Most studies have also assumed that nonphotosynthetic vegetation (litter and stems) contributes little to fAPAR. Using a combined field measurement and radiative transfer modeling approach, we quantified (a) the relative role of the leaf-, canopy-, and landscape-level factors that determine fAPAR in terrestrial ecosystems and (b) the magnitude of PAR absorption by grass litter and woody plant stems. Variability in full spectral-range (400–2500 nm) reflectance/transmittance and PAR (400–700 nm) absorption at the level of individual leaf, stem, and litter samples was quantified for a wide array of broadleaf arborescent and grass species along a 900-km north–south Texas savanna transect. Among woody growth forms, leaf reflectance and transmittance spectra were statistically comparable between populations, species within a genus, and functional types (deciduous vs. evergreen, legume vs. nonlegume). Within the grass life-form, spectral properties were statistically comparable between species and C 3 /C 4 physiologies. We found that tissue-level PAR absorption among species, genera, functional groups, and growth forms and between climatologically diverse regions

  14. Radionuclides in the terrestrial ecosystem near a Canadian uranium mill -- Part 2: Small mammal food chains and bioavailability

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, P.A.

    2000-06-01

    Food chain transfer through the soil-vegetation-small mammal food chain was measured by concentration ratios (CRs) for uranium, {sup 226}Ra, {sup 210}Pb, and {sup 210}Po at three sites near the Key Lake uranium mill in northern Saskatchewan. Plant/soil CRs, animal carcass/GI tract CRs, and animal/soil CRs were depressed at sites impacted by mill and tailings dusts relative to a nearby control site. Thus, radionuclides associated with large particulates in tailings and/or ore dusts may be less bioavailable to terrestrial plants and animals than natural sources of radioactive dust. These results show that reliance on default food chain transfer parameters, obtained from uncontaminated terrestrial ecosystems, may overpredict impacts at uranium mine and mill sites. Given the omnivorous diet of small mammals and birds, animal/soil CRs are recommended as the most cost-effective and robust means of predicting animal concentrations from environmental monitoring data at uranium mill facilities.

  15. Radionuclides in the terrestrial ecosystem near a Canadian uranium mill -- Part 2: Small mammal food chains and bioavailability

    International Nuclear Information System (INIS)

    Thomas, P.A.

    2000-01-01

    Food chain transfer through the soil-vegetation-small mammal food chain was measured by concentration ratios (CRs) for uranium, 226 Ra, 210 Pb, and 210 Po at three sites near the Key Lake uranium mill in northern Saskatchewan. Plant/soil CRs, animal carcass/GI tract CRs, and animal/soil CRs were depressed at sites impacted by mill and tailings dusts relative to a nearby control site. Thus, radionuclides associated with large particulates in tailings and/or ore dusts may be less bioavailable to terrestrial plants and animals than natural sources of radioactive dust. These results show that reliance on default food chain transfer parameters, obtained from uncontaminated terrestrial ecosystems, may overpredict impacts at uranium mine and mill sites. Given the omnivorous diet of small mammals and birds, animal/soil CRs are recommended as the most cost-effective and robust means of predicting animal concentrations from environmental monitoring data at uranium mill facilities

  16. Early Cretaceous terrestrial ecosystems in East Asia based on food-web and energy-flow models

    Science.gov (United States)

    Matsukawa, M.; Saiki, K.; Ito, M.; Obata, I.; Nichols, D.J.; Lockley, M.G.; Kukihara, R.; Shibata, K.

    2006-01-01

    In recent years, there has been global interest in the environments and ecosystems around the world. It is helpful to reconstruct past environments and ecosystems to help understand them in the present and the future. The present environments and ecosystems are an evolving continuum with those of the past and the future. This paper demonstrates the contribution of geology and paleontology to such continua. Using fossils, we can make an estimation of past population density as an ecosystem index based on food-web and energy-flow models. Late Mesozoic nonmarine deposits are distributed widely on the eastern Asian continent and contain various kinds of fossils such as fishes, amphibians, reptiles, dinosaurs, mammals, bivalves, gastropods, insects, ostracodes, conchostracans, terrestrial plants, and others. These fossil organisms are useful for late Mesozoic terrestrial ecosystem reconstruction using food-web and energy-flow models. We chose Early Cretaceous fluvio-lacustrine basins in the Choyr area, southeastern Mongolia, and the Tetori area, Japan, for these analyses and as a potential model for reconstruction of other similar basins in East Asia. The food-web models are restored based on taxa that occurred in these basins. They form four or five trophic levels in an energy pyramid consisting of rich primary producers at its base and smaller biotas higher in the food web. This is the general energy pyramid of a typical ecosystem. Concerning the population densities of vertebrate taxa in 1 km2 in these basins, some differences are recognized between Early Cretaceous and the present. For example, Cretaceous estimates suggest 2.3 to 4.8 times as many herbivores and 26.0 to 105.5 times the carnivore population. These differences are useful for the evaluation of past population densities of vertebrate taxa. Such differences may also be caused by the different metabolism of different taxa. Preservation may also be a factor, and we recognize that various problems occur in

  17. Biome-BGC: Terrestrial Ecosystem Process Model, Version 4.1.1

    Data.gov (United States)

    National Aeronautics and Space Administration — Biome-BGC is a computer program that estimates fluxes and storage of energy, water, carbon, and nitrogen for the vegetation and soil components of terrestrial...

  18. A model using marginal efficiency of investment to analyse carbon and nitrogen interactions in terrestrial ecosystems (ACONITE Version 1)

    Science.gov (United States)

    Thomas, R. Q.; Williams, M.

    2014-04-01

    Carbon (C) and nitrogen (N) cycles are coupled in terrestrial ecosystems through multiple processes including photosynthesis, tissue allocation, respiration, N fixation, N uptake, and decomposition of litter and soil organic matter. Capturing the constraint of N on terrestrial C uptake and storage has been a focus of the Earth System modelling community. However there is little understanding of the trade-offs and sensitivities of allocating C and N to different tissues in order to optimize the productivity of plants. Here we describe a new, simple model of ecosystem C-N cycling and interactions (ACONITE), that builds on theory related to plant economics in order to predict key ecosystem properties (leaf area index, leaf C : N, N fixation, and plant C use efficiency) using emergent constraints provided by marginal returns on investment for C and/or N allocation. We simulated and evaluated steady-state ecosystem stocks and fluxes in three different forest ecosystems types (tropical evergreen, temperate deciduous, and temperate evergreen). Leaf C : N differed among the three ecosystem types (temperate deciduous database describing plant traits. Gross primary productivity (GPP) and net primary productivity (NPP) estimates compared well to observed fluxes at the simulation sites. Simulated N fixation at steady-state, calculated based on relative demand for N and the marginal return on C investment to acquire N, was an order of magnitude higher in the tropical forest than in the temperate forest, consistent with observations. A sensitivity analysis revealed that parameterization of the relationship between leaf N and leaf respiration had the largest influence on leaf area index and leaf C : N. Also, a widely used linear leaf N-respiration relationship did not yield a realistic leaf C : N, while a more recently reported non-linear relationship performed better. A parameter governing how photosynthesis scales with day length had the largest influence on total vegetation C

  19. A model using marginal efficiency of investment to analyze carbon and nitrogen interactions in terrestrial ecosystems (ACONITE Version 1)

    Science.gov (United States)

    Thomas, R. Q.; Williams, M.

    2014-09-01

    Carbon (C) and nitrogen (N) cycles are coupled in terrestrial ecosystems through multiple processes including photosynthesis, tissue allocation, respiration, N fixation, N uptake, and decomposition of litter and soil organic matter. Capturing the constraint of N on terrestrial C uptake and storage has been a focus of the Earth System Modeling community. However, there is little understanding of the trade-offs and sensitivities of allocating C and N to different tissues in order to optimize the productivity of plants. Here we describe a new, simple model of ecosystem C-N cycling and interactions (ACONITE), that builds on theory related to plant economics in order to predict key ecosystem properties (leaf area index, leaf C : N, N fixation, and plant C use efficiency) based on the outcome of assessments of the marginal change in net C or N uptake associated with a change in allocation of C or N to plant tissues. We simulated and evaluated steady-state ecosystem stocks and fluxes in three different forest ecosystems types (tropical evergreen, temperate deciduous, and temperate evergreen). Leaf C : N differed among the three ecosystem types (temperate deciduous database describing plant traits. Gross primary productivity (GPP) and net primary productivity (NPP) estimates compared well to observed fluxes at the simulation sites. Simulated N fixation at steady-state, calculated based on relative demand for N and the marginal return on C investment to acquire N, was an order of magnitude higher in the tropical forest than in the temperate forest, consistent with observations. A sensitivity analysis revealed that parameterization of the relationship between leaf N and leaf respiration had the largest influence on leaf area index and leaf C : N. A parameter governing how photosynthesis scales with day length had the largest influence on total vegetation C, GPP, and NPP. Multiple parameters associated with photosynthesis, respiration, and N uptake influenced the rate of N

  20. Spatial distribution of caesium-137 in soil cover of background terrestrial ecosystems, Central European Russia

    Energy Technology Data Exchange (ETDEWEB)

    Paramonova, Tatiana A. [Radioecology and Ecotoxicology Department of Soil Science Faculty, Moscow State Lomonosov University, 119234 Moscow (Russian Federation); Shamshurina, Evgenia N. [Laboratory of soil erosion and fluvial processes of Geography Faculty, Moscow State Lomonosov University, 119234 Moscow (Russian Federation)

    2014-07-01

    ¹³⁷Cs - the main long-living anthropogenic radionuclide - arrived in mass at Russian terrestrial ecosystems after nuclear tests in the atmosphere in 1960-yy. and after Chernobyl accident in 1986 y., but in spite of a long period since these events soil cover contamination by ¹³⁷Cs is considered as extremely resistant due to its firmly fixation by soil solid matter and a long half-life of the radionuclide. Wide-scale investigation in maximal diversity of natural, semi-natural and anthropogenic landscapes of Central European Russia (more than 400 soils samples from Vologda, Yaroslavl, Ivanovo, Tver regions which are representative for the southern taiga zone) demonstrates that modern average specific activity of ¹³⁷Cs in the upper 15-cm layer of soil is 11±3 Bq/kg (contamination density 0.05±0.01 Ci/km²), that is fully ecologically acceptable. It is important that the average concentrations of ¹³⁷Cs in the soil cover of individual regions are close to each other. The most likely these average values are approximate assessment of background radioactive contamination of soils in central European Russia outside of the immediate Chernobyl trace. At the same time approximately 3% of soils are characterized by elevated ¹³⁷Cs content - 62-98 Bq/kg (0.24-0.43 Ci/km²), that indicates the presence of low radioactive spots on the territory and may be considered as local Chernobyl fallout. All of them attribute with forest soils which are commonly characterized by considerably more high accumulation of ¹³⁷Cs (18±5 Bq/kg, 0.06±0.01 Ci/km²) due to advanced absorbing surface of trees. Agricultural lands (plagued or under meadows) and soils of industrial plots with scarce vegetation contain only 6±2 Bq/kg (0.03±0.01 Ci/km²) of ¹³⁷Cs. About 84-92% of ¹³⁷Cs are concentrated in the upper 15-cm layer of natural soils or in Ap horizon of plagued soils, thus vertical migration of radionuclide is very slow in spite of ~30 years after Chernobyl

  1. Mapping and Quantifying Biodiversity and Ecosystem Services Related to Terrestrial Vertebrates: A National Approach

    Science.gov (United States)

    Biodiversity is crucial for the functioning of ecosystems and the products and services from which we transform natural assets of the Earth for human survival, security, and well-being. The ability to assess, report, map, and forecast the life support functions of ecosystems is a...

  2. A National Approach to Map and Quantify Terrestrial Vertebrate Biodiversity within an Ecosystem Services Framework

    Science.gov (United States)

    Biodiversity is crucial for the functioning of ecosystems and the products and services from which we transform natural assets of the Earth for human survival, security, and well-being. The ability to assess, report, map, and forecast the life support functions of ecosystems is a...

  3. Risk assessment for human health and terrestrial ecosystem under chronic radioactive pollution near regional radioactive waste storage

    Science.gov (United States)

    Lavrentyeva, G. V.; Katkova, M. N.; Shoshina, R. R.; Synzynys, B. I.

    2017-01-01

    An impact of the radioactive waste storage facility at the regional population was assessed under supervision of IAEA. It was made in accordance with the methodology for assessment of doses and risks to human storage using different scenarios of radionuclides releases into the environment. The following scenarios were considered: leakage of fluid, resuspension of dust, fire, flooding. Thy evaluation of radiation doses received and the risks to the human showed that the risk has been acceptable for all scenarios. An approach for an ecological risk assessment for terrestrial ecosystem is presented as five modules: selection of the ecosystem-receptor of radiation effects; determination of reference species of living organisms and their survival indices; the critical load as an absorbed dose rate is calculated from the dependence between the absorbed Sr-90 radiation dose rate and the coefficient of radioactive strontium accumulation in mollusc shells; the critical dose; risk is assessed from a part of the ecosystem territory with increased mollusc loading; uncertainties appeared at each stage of risk assessment are characterized. The risk of exposure to the repository on the ecosystem should be characterized as unacceptable.

  4. Risk assessment for human health and terrestrial ecosystem under chronic radioactive pollution near regional radioactive waste storage

    International Nuclear Information System (INIS)

    Lavrentyeva, G V; Katkova, M N; Shoshina, R R; Synzynys, B I

    2017-01-01

    An impact of the radioactive waste storage facility at the regional population was assessed under supervision of IAEA. It was made in accordance with the methodology for assessment of doses and risks to human storage using different scenarios of radionuclides releases into the environment. The following scenarios were considered: leakage of fluid, resuspension of dust, fire, flooding. Thy evaluation of radiation doses received and the risks to the human showed that the risk has been acceptable for all scenarios. An approach for an ecological risk assessment for terrestrial ecosystem is presented as five modules: selection of the ecosystem-receptor of radiation effects; determination of reference species of living organisms and their survival indices; the critical load as an absorbed dose rate is calculated from the dependence between the absorbed Sr-90 radiation dose rate and the coefficient of radioactive strontium accumulation in mollusc shells; the critical dose; risk is assessed from a part of the ecosystem territory with increased mollusc loading; uncertainties appeared at each stage of risk assessment are characterized. The risk of exposure to the repository on the ecosystem should be characterized as unacceptable. (paper)

  5. Changes of evapotranspiration and water yield in China's terrestrial ecosystems during the period from 2000 to 2010

    Science.gov (United States)

    Liu, Y.; Zhou, Y.; Ju, W.; Chen, J.; Wang, S.; He, H.; Wang, H.; Guan, D.; Zhao, F.; Li, Y.; Hao, Y.

    2013-04-01

    Terrestrial carbon and water cycles are interactively linked at various spatial and temporal scales. Evapotranspiration (ET) plays a key role in the terrestrial water cycle and altering carbon sequestration of terrestrial ecosystems. The study of ET and its response to climate and vegetation changes is critical in China since water availability is a limiting factor for the functioning of terrestrial ecosystems in vast arid and semiarid regions. In this study, the process-based Boreal Ecosystem Productivity Simulator (BEPS) model was employed in conjunction with a newly developed leaf area index (LAI) dataset and other spatial data to simulate daily ET and water yield at a spatial resolution of 500 m over China for the period from 2000 to 2010. The spatial and temporal variations of ET and water yield and influences of temperature, precipitation, land cover types, and LAI on ET were analyzed. The validations with ET measured at 5 typical ChinaFLUX sites and inferred using statistical hydrological data in 10 basins showed that the BEPS model was able to simulate daily and annual ET well at site and basin scales. Simulated annual ET exhibited a distinguishable southeast to northwest decreasing gradient, corresponding to climate conditions and vegetation types. It increased with the increase of LAI in 74% of China's landmass and was positively correlated with temperature in most areas of southwest, south, east, and central China and with precipitation in the arid and semiarid areas of northwest and north China. In the Tibet Plateau and humid southeast China, the increase in precipitation might cause ET to decrease. The national mean annual ET varied from 345.5 mm yr-1 in 2001 to 387.8 mm yr-1 in 2005, with an average of 369.8 mm yr-1 during the study period. The overall increase rate of 1.7 mm yr-2 (r = 0.43 p = 0.19) was mainly driven by the increase of total ET in forests. During the period from 2006 to 2009, precipitation and LAI decreased widely and consequently

  6. Global Trends in Exposure to Light Pollution in Natural Terrestrial Ecosystems

    Directory of Open Access Journals (Sweden)

    Jonathan Bennie

    2015-03-01

    Full Text Available The rapid growth in electric light usage across the globe has led to increasing presence of artificial light in natural and semi-natural ecosystems at night. This occurs both due to direct illumination and skyglow - scattered light in the atmosphere. There is increasing concern about the effects of artificial light on biological processes, biodiversity and the functioning of ecosystems. We combine intercalibrated Defense Meteorological Satellite Program’s Operational Linescan System (DMSP/OLS images of stable night-time lights for the period 1992 to 2012 with a remotely sensed landcover product (GLC2000 to assess recent changes in exposure to artificial light at night in 43 global ecosystem types. We find that Mediterranean-climate ecosystems have experienced the greatest increases in exposure, followed by temperate ecosystems. Boreal, Arctic and montane systems experienced the lowest increases. In tropical and subtropical regions, the greatest increases are in mangroves and subtropical needleleaf and mixed forests, and in arid regions increases are mainly in forest and agricultural areas. The global ecosystems experiencing the greatest increase in exposure to artificial light are already localized and fragmented, and often of particular conservation importance due to high levels of diversity, endemism and rarity. Night time remote sensing can play a key role in identifying the extent to which natural ecosystems are exposed to light pollution.

  7. Future of African terrestrial biodiversity and ecosystems under anthropogenic climate change

    Science.gov (United States)

    Midgley, Guy F.; Bond, William J.

    2015-09-01

    Projections of ecosystem and biodiversity change for Africa under climate change diverge widely. More than other continents, Africa has disturbance-driven ecosystems that diversified under low Neogene CO2 levels, in which flammable fire-dependent C4 grasses suppress trees, and mega-herbivore action alters vegetation significantly. An important consequence is metastability of vegetation state, with rapid vegetation switches occurring, some driven by anthropogenic CO2-stimulated release of trees from disturbance control. These have conflicting implications for biodiversity and carbon sequestration relevant for policymakers and land managers. Biodiversity and ecosystem change projections need to account for both disturbance control and direct climate control of vegetation structure and function.

  8. Geospatial variability of soil CO2-C exchange in the main terrestrial ecosystems of Keller Peninsula, Maritime Antarctica.

    Science.gov (United States)

    Thomazini, A; Francelino, M R; Pereira, A B; Schünemann, A L; Mendonça, E S; Almeida, P H A; Schaefer, C E G R

    2016-08-15

    Soils and vegetation play an important role in the carbon exchange in Maritime Antarctica but little is known on the spatial variability of carbon processes in Antarctic terrestrial environments. The objective of the current study was to investigate (i) the soil development and (ii) spatial variability of ecosystem respiration (ER), net ecosystem CO2 exchange (NEE), gross primary production (GPP), soil temperature (ST) and soil moisture (SM) under four distinct vegetation types and a bare soil in Keller Peninsula, King George Island, Maritime Antarctica, as follows: site 1: moss-turf community; site 2: moss-carpet community; site 3: phanerogamic antarctic community; site 4: moss-carpet community (predominantly colonized by Sanionia uncinata); site 5: bare soil. Soils were sampled at different layers. A regular 40-point (5×8 m) grid, with a minimum separation distance of 1m, was installed at each site to quantify the spatial variability of carbon exchange, soil moisture and temperature. Vegetation characteristics showed closer relation with soil development across the studied sites. ER reached 2.26μmolCO2m(-2)s(-1) in site 3, where ST was higher (7.53°C). A greater sink effect was revealed in site 4 (net uptake of 1.54μmolCO2m(-2)s(-1)) associated with higher SM (0.32m(3)m(-3)). Spherical models were fitted to describe all experimental semivariograms. Results indicate that ST and SM are directly related to the spatial variability of CO2 exchange. Heterogeneous vegetation patches showed smaller range values. Overall, poorly drained terrestrial ecosystems act as CO2 sink. Conversely, where ER is more pronounced, they are associated with intense soil carbon mineralization. The formations of new ice-free areas, depending on the local soil drainage condition, have an important effect on CO2 exchange. With increasing ice/snow melting, and resulting widespread waterlogging, increasing CO2 sink in terrestrial ecosystems is expected for Maritime Antarctica. Copyright

  9. Characterisation of perfluorooctane sulfonate (PFOS) in a terrestrial ecosystem near a fluorochemical plant in Flanders, Belgium

    NARCIS (Netherlands)

    D'Hollander, W.; De Bruyn, L.; Hagenaars, A; de Voogt, P.; Bervoets, L.

    2014-01-01

    Bioaccumulation of perfluorooctane sulfonate (PFOS) in a restricted terrestrial food chain was investigated with the omnivorous wood mouse (Apodemus sylvaticus) on top of the studied food chain. The levels detected are very high compared with literature as a result of the presence of fluorochemical

  10. Merging paleobiology with conservation biology to guide the future of terrestrial ecosystems.

    Science.gov (United States)

    Barnosky, Anthony D; Hadly, Elizabeth A; Gonzalez, Patrick; Head, Jason; Polly, P David; Lawing, A Michelle; Eronen, Jussi T; Ackerly, David D; Alex, Ken; Biber, Eric; Blois, Jessica; Brashares, Justin; Ceballos, Gerardo; Davis, Edward; Dietl, Gregory P; Dirzo, Rodolfo; Doremus, Holly; Fortelius, Mikael; Greene, Harry W; Hellmann, Jessica; Hickler, Thomas; Jackson, Stephen T; Kemp, Melissa; Koch, Paul L; Kremen, Claire; Lindsey, Emily L; Looy, Cindy; Marshall, Charles R; Mendenhall, Chase; Mulch, Andreas; Mychajliw, Alexis M; Nowak, Carsten; Ramakrishnan, Uma; Schnitzler, Jan; Das Shrestha, Kashish; Solari, Katherine; Stegner, Lynn; Stegner, M Allison; Stenseth, Nils Chr; Wake, Marvalee H; Zhang, Zhibin

    2017-02-10

    Conservation of species and ecosystems is increasingly difficult because anthropogenic impacts are pervasive and accelerating. Under this rapid global change, maximizing conservation success requires a paradigm shift from maintaining ecosystems in idealized past states toward facilitating their adaptive and functional capacities, even as species ebb and flow individually. Developing effective strategies under this new paradigm will require deeper understanding of the long-term dynamics that govern ecosystem persistence and reconciliation of conflicts among approaches to conserving historical versus novel ecosystems. Integrating emerging information from conservation biology, paleobiology, and the Earth sciences is an important step forward on the path to success. Maintaining nature in all its aspects will also entail immediately addressing the overarching threats of growing human population, overconsumption, pollution, and climate change. Copyright © 2017, American Association for the Advancement of Science.

  11. The effects of land cover and land use change on the contemporary carbon balance of the arctic and boreal terrestrial ecosystems of northern Eurasia

    Science.gov (United States)

    Hayes, Daniel J.; McGuire, A. David; Kicklighter, David W.; Burnside , Todd J.; Melillo, Jerry M.

    2010-01-01

    Recent changes in climate, disturbance regimes and land use and management systems in Northern Eurasia have the potential to disrupt the terrestrial sink of atmospheric CO2 in a way that accelerates global climate change. To determine the recent trends in the carbon balance of the arctic and boreal ecosystems of this region, we performed a retrospective analysis of terrestrial carbon dynamics across northern Eurasia over a recent 10-year period using a terrestrial biogeochemical process model. The results of the simulations suggest a shift in direction of the net flux from the terrestrial sink of earlier decades to a net source on the order of 45 Tg C year−1between 1997 and 2006. The simulation framework and subsequent analyses presented in this study attribute this shift to a large loss of carbon from boreal forest ecosystems, which experienced a trend of decreasing precipitation and a large area burned during this time period.

  12. Outdoor Terrestrial Model Ecosystems are suitable to detect pesticide effects on soil fauna: design and method development.

    Science.gov (United States)

    Scholz-Starke, B; Nikolakis, A; Leicher, T; Lechelt-Kunze, C; Heimbach, F; Theissen, B; Toschki, A; Ratte, H T; Schäffer, A; Ross-Nickoll, M

    2011-11-01

    Terrestrial Model Ecosystems (TME) were developed as one higher-tier option to detect and assess effects of pesticides on soil communities in a 1 year study using lindane (gamma-HCH) as a persistent and toxic reference pesticide. TME contained intact soil cores (diameter 300 mm, height 400 mm) including indigenous soil communities of undisturbed grassland. Forty units were placed outdoors between spring 2005 and 2006. The TME experiment was designed to provide data that fulfill the requirements of the revised European regulation on plant protection products (regulation 1107/2009/EEC replacing guideline 91/414/EC) with a focus on structural endpoints such as soil organisms and their community structure in case higher-tier evaluation is triggered. The key objective was to evaluate the dynamics and stability of species-diverse microarthropod communities of undisturbed grassland over at least 1 year after application. In grassland soils, less selection pressure towards insensitive species compared to arable land was presumed. Sufficient numbers of organisms and numerous TME replicates ensured that a statistical evaluation could be performed to estimate the sensitivity of the organisms upon application of lindane applied at high rates of 7.5 and 75 kg ai/ha. The application rates resulted in nominal concentrations of 10 and 100 mg ai/kg dry soil referred to the top 5 cm soil layer of 10 TME each; 20 untreated TME served as controls and were used to study the natural dynamics and the variability of populations under field conditions. Results showed that the grassland from which the soil cores were sampled contained communities of soil organisms marked by typical diversity of improved grassland. Lindane applied at excessive rates caused clear dose-related and long-lasting effects on the communities of microarthropods. On the contrary, lumbricids, the total feeding activity (bait lamina) and the growth of plant biomass were not affected up to 1 year after application

  13. Restoration of Degraded Salt Affected Lands to Productive Forest Ecosystem

    Science.gov (United States)

    Singh, Yash; Singh, Gurbachan; Singh, Bajrang; Cerdà, Artemi

    2017-04-01

    Soil system determines the fluxes of energy and matter in the Earth and is the source of goods, services and resources to the humankind (Keesstra et al., 2012; Brevik et al., 2015; Keesstra et al., 2016). To restore and rehabilitate the soil system is a key strategy to recover the services the soils offers (Celentano et al., 2016; Galati et al., 2016; Parras-Alcantara et al., 2016). Transformation of degraded sodic lands in biodiversity rich productive forest ecosystem is a challenging task before the researchers all over the world. The soils of the degraded sites remain almost unfavorable for the normal growth, development and multiplication of organisms; all our attempts tend to alleviate the soil constraints. Land degradation due to presence of salts in the soil is an alarming threat to agricultural productivity and sustainability, particularly in arid and semiarid regions of the world (Tanji, 1990; Qadir et al., 2006). According to the FAO Land and Nutrition Management Service (2008), over 6% of the world's lands are affected by salinity, which accounts for more than 800 million ha in 100 countries. This is due to natural causes, extensive utilization of land (Egamberdieva et al., 2008), poor drainage systems and limited availability of irrigation water which causes salinization in many irrigated soils (Town et al., 2008).In India, about 6.73 million ha are salt affected which spread in 194 districts out of 584 districts in India and represents 2.1% of the geographical area of the country (Mandal et al., 2009).Out of these, 2.8 million ha are sodic in nature and primarily occurring in the Indo-Gangetic alluvial plains. These lands are degraded in structural, chemical, nutritional, hydrological and microbiological characteristics. The reclamation of salt affected soils with chemical amendments like gypsum and phospho-gypsum are in practice for the cultivation field crops under agricultural production. Forest development on such lands although takes considerable

  14. Soil CO2 dynamics and fluxes as affected by tree harvest in an experimental sand ecosystem.

    Science.gov (United States)

    C.K. Keller; T.M. White; R. O' Brien; J.L. Smith

    2006-01-01

    Soil CO2 production is a key process in ecosystem C exchange, and global change predictions require understanding of how ecosystem disturbance affects this process. We monitored CO2 levels in soil gas and as bicarbonate in drainage from an experimental red pine ecosystem, for 1 year before and 3 years after its aboveground...

  15. Geospatial Analysis of Climate-Related Changes in North American Arctic Ecosystems and Implications for Terrestrial Flora and Fauna

    Science.gov (United States)

    Amirazodi, S.; Griffin, R.

    2016-12-01

    Climate change induces range shifts among many terrestrial species in Arctic regions. At best, warming often forces poleward migration if a stable environment is to be maintained. At worst, marginal ecosystems may disappear entirely without a contiguous shift allowing migratory escape to similar environs. These changing migration patterns and poleward range expansion push species into higher latitudes where ecosystems are less stable and more sensitive to change. This project focuses on ecosystem geography and interspecies relationships and interactions by analyzing seasonality and changes over time in variables including the following: temperature, precipitation, vegetation, physical boundaries, population demographics, permafrost, sea ice, and food and water availability. Publicly available data from remote sensing platforms are used throughout, and processed with both commercially available and open sourced GIS tools. This analysis describes observed range changes for selected North American species, and attempts to provide insight into the causes and effects of these phenomena. As the responses to climate change are complex and varied, the goal is to produce the aforementioned results in an easily understood set of geospatial representations to better support decision making regarding conservation prioritization and enable adaptive responses and mitigation strategies.

  16. Assessment of land use impact on water-related ecosystem services capturing the integrated terrestrial-aquatic system.

    Science.gov (United States)

    Maes, Wouter H; Heuvelmans, Griet; Muys, Bart

    2009-10-01

    Although the importance of green (evaporative) water flows in delivering ecosystem services has been recognized, most operational impact assessment methods still focus only on blue water flows. In this paper, we present a new model to evaluate the effect of land use occupation and transformation on water quantity. Conceptually based on the supply of ecosystem services by terrestrial and aquatic ecosystems, the model is developed for, but not limited to, land use impact assessment in life cycle assessment (LCA) and requires a minimum amount of input data. Impact is minimal when evapotranspiration is equal to that of the potential natural vegetation, and maximal when evapotranspiration is zero or when it exceeds a threshold value derived from the concept of environmental water requirement. Three refinements to the model, requiring more input data, are proposed. The first refinement considers a minimal impact over a certain range based on the boundary evapotranspiration of the potential natural vegetation. In the second refinement the effects of evaporation and transpiration are accounted for separately, and in the third refinement a more correct estimate of evaporation from a fully sealed surface is incorporated. The simplicity and user friendliness of the proposed impact assessment method are illustrated with two examples.

  17. Transfer of radiocesium through natural ecosystems to foodstuffs of terrestrial origin in Finland

    International Nuclear Information System (INIS)

    Rantavaara, A.H.

    1990-01-01

    Since autumn 1986, the dietary radiocesium received in Finland from terrestrial wild products has not shown any marked change. After 1987, the relative contribution of game meat, wild berries and mushrooms to the intake started to increase, due to the decrease in intake via agricultural and garden products after 1986, and via freshwater fish after 1987. The estimates for the total intake of 137 Cs in the three 12-month periods after April 1986 were 34, 33 and 22 Bq d -1 . The contributions of wild products of terrestrial origin to the intake were 9, 9 and 13 per cent. The contribution of freshwater fish was considerable when estimated on the basis of normal consumption of fish for human food: 18, 40 and 38%. (author)

  18. Quantifying regional changes in terrestrial carbon storage by extrapolation from local ecosystem models

    Energy Technology Data Exchange (ETDEWEB)

    King, A W

    1991-12-31

    A general procedure for quantifying regional carbon dynamics by spatial extrapolation of local ecosystem models is presented Monte Carlo simulation to calculate the expected value of one or more local models, explicitly integrating the spatial heterogeneity of variables that influence ecosystem carbon flux and storage. These variables are described by empirically derived probability distributions that are input to the Monte Carlo process. The procedure provides large-scale regional estimates based explicitly on information and understanding acquired at smaller and more accessible scales.Results are presented from an earlier application to seasonal atmosphere-biosphere CO{sub 2} exchange for circumpolar ``subarctic`` latitudes (64{degree}N-90{degree}N). Results suggest that, under certain climatic conditions, these high northern ecosystems could collectively release 0.2 Gt of carbon per year to the atmosphere. I interpret these results with respect to questions about global biospheric sinks for atmospheric CO{sub 2} .

  19. Representation of Ecosystem Services by Terrestrial Protected Areas: Chile as a Case Study

    Science.gov (United States)

    Durán, América P.; Casalegno, Stefano; Marquet, Pablo A.; Gaston, Kevin J.

    2013-01-01

    Protected areas are increasingly considered to play a key role in the global maintenance of ecosystem processes and the ecosystem services they provide. It is thus vital to assess the extent to which existing protected area systems represent those services. Here, for the first time, we document the effectiveness of the current Chilean protected area system and its planned extensions in representing both ecosystem services (plant productivity, carbon storage and agricultural production) and biodiversity. Additionally, we evaluate the effectiveness of protected areas based on their respective management objectives. Our results show that existing protected areas in Chile do not contain an unusually high proportion of carbon storage (14.9%), agricultural production (0.2%) or biodiversity (11.8%), and also represent a low level of plant productivity (Normalized Difference Vegetation Index of 0.38). Proposed additional priority sites enhance the representation of ecosystem services and biodiversity, but not sufficiently to attain levels of representation higher than would be expected for their area of coverage. Moreover, when the species groups were assessed separately, amphibians was the only one well represented. Suggested priority sites for biodiversity conservation, without formal protection yet, was the only protected area category that over-represents carbon storage, agricultural production and biodiversity. The low representation of ecosystem services and species’ distribution ranges by the current protected area system is because these protected areas are heavily biased toward southern Chile, and contain large extents of ice and bare rock. The designation and management of proposed priority sites needs to be addressed in order to increase the representation of ecosystem services within the Chilean protected area system. PMID:24376559

  20. Simulated sensitivity of African terrestrial ecosystem photosynthesis to rainfall frequency, intensity, and rainy season length

    Science.gov (United States)

    Guan, Kaiyu; Good, Stephen P.; Caylor, Kelly K.; Medvigy, David; Pan, Ming; Wood, Eric F.; Sato, Hisashi; Biasutti, Michela; Chen, Min; Ahlström, Anders; Xu, Xiangtao

    2018-02-01

    There is growing evidence of ongoing changes in the statistics of intra-seasonal rainfall variability over large parts of the world. Changes in annual total rainfall may arise from shifts, either singly or in a combination, of distinctive intra-seasonal characteristics -i.e. rainfall frequency, rainfall intensity, and rainfall seasonality. Understanding how various ecosystems respond to the changes in intra-seasonal rainfall characteristics is critical for predictions of future biome shifts and ecosystem services under climate change, especially for arid and semi-arid ecosystems. Here, we use an advanced dynamic vegetation model (SEIB-DGVM) coupled with a stochastic rainfall/weather simulator to answer the following question: how does the productivity of ecosystems respond to a given percentage change in the total seasonal rainfall that is realized by varying only one of the three rainfall characteristics (rainfall frequency, intensity, and rainy season length)? We conducted ensemble simulations for continental Africa for a realistic range of changes (-20% ~ +20%) in total rainfall amount. We find that the simulated ecosystem productivity (measured by gross primary production, GPP) shows distinctive responses to the intra-seasonal rainfall characteristics. Specifically, increase in rainfall frequency can lead to 28% more GPP increase than the same percentage increase in rainfall intensity; in tropical woodlands, GPP sensitivity to changes in rainy season length is ~4 times larger than to the same percentage changes in rainfall frequency or intensity. In contrast, shifts in the simulated biome distribution are much less sensitive to intra-seasonal rainfall characteristics than they are to total rainfall amount. Our results reveal three major distinctive productivity responses to seasonal rainfall variability—‘chronic water stress’, ‘acute water stress’ and ‘minimum water stress’ - which are respectively associated with three broad spatial patterns of

  1. Spatial and temporal patterns of CH4 and N2O fluxes in terrestrial ecosystems of North America during 1979–2008: application of a global biogeochemistry model

    Directory of Open Access Journals (Sweden)

    C. Lu

    2010-09-01

    Full Text Available Continental-scale estimations of terrestrial methane (CH4 and nitrous oxide (N2O fluxes over a long time period are crucial to accurately assess the global balance of greenhouse gases and enhance our understanding and prediction of global climate change and terrestrial ecosystem feedbacks. Using a process-based global biogeochemical model, the Dynamic Land Ecosystem Model (DLEM, we quantified simultaneously CH4 and N2O fluxes in North America's terrestrial ecosystems from 1979 to 2008. During the past 30 years, approximately 14.69 ± 1.64 T g C a−1 (1 T g = 1012 g of CH4, and 1.94 ± 0.1 T g N a−1 of N2O were released from terrestrial ecosystems in North America. At the country level, both the US and Canada acted as CH4 sources to the atmosphere, but Mexico mainly oxidized and consumed CH4 from the atmosphere. Wetlands in North America contributed predominantly to the regional CH4 source, while all other ecosystems acted as sinks for atmospheric CH4, of which forests accounted for 36.8%. Regarding N2O emission in North America, the US, Canada, and Mexico contributed 56.19%, 18.23%, and 25.58%, respectively, to the continental source over the past 30 years. Forests and croplands were the two ecosystems that contributed most to continental N2O emission. The inter-annual variations of CH4 and N2O fluxes in North America were mainly attributed to year-to-year climatic variability. While only annual precipitation was found to have a significant effect on annual CH4 flux, both mean annual temperature and annual precipitation were significantly correlated to annual N2O flux. The regional estimates and spatiotemporal patterns of terrestrial ecosystem CH4 and N2O fluxes in North America generated in this study provide useful information for global change research and policy making.

  2. Carbon dioxide exchange in the High Arctic - examples from terrestrial ecosystems

    DEFF Research Database (Denmark)

    Grøndahl, L.

    of the growing season, which in combination with high temperatures increased uptake rates. The dry heath ecosystem in general gained carbon during the summer season in the order of magnitude -1.4 gCm-2 up to 32 gCm-2. This result is filling out a gap of knowledge on the response of high Arctic ecosystems...... the measurements conducted in the valley to a regional level. Including information on temporal and spatial variability in air temperature and radiation, together with NDVI and a vegetation map a regional estimate of the CO2 exchange during the summer was provided, elaborating the NDVI based estimate on net carbon...

  3. El Niño effects on the dynamics of terrestrial ecosystems

    NARCIS (Netherlands)

    Holmgren, M.; Scheffer, M.; Ezcurra, E.; Gutiérrez, J.R.; Mohren, G.M.J.

    2001-01-01

    New studies are showing that the El Niño Southern Oscillation (ENSO) has major implications for the functioning of different ecosystems, ranging from deserts to tropical rain forests. ENSO-induced pulses of enhanced plant productivity can cascade upward through the food web invoking unforeseen

  4. Applications of the First Law to Ecological Systems. Physical Processes in Terrestrial and Aquatic Ecosystems, Thermodynamics.

    Science.gov (United States)

    Stevenson, R. D.

    These materials were designed to be used by life science students for instruction in the application of physical theory to ecosystem operation. Most modules contain computer programs which are built around a particular application of a physical process. This report describes concepts presented in another module called "The First Law of…

  5. Modelling carbon and water flows in terrestrial ecosystems in the boreal zone - examples from Oskarshamn

    Energy Technology Data Exchange (ETDEWEB)

    Karlberg, Louise [Stockholm Environment Institute (SEI), Stockholm (Sweden); Gu stafsson, David; Jansson, Per-Erik [Royal Inst. of Technology, Dept. of Land and Water Resources Engineering, Stockholm (Sweden)

    2007-12-15

    Carbon budgets and mean residence times were estimated in four hypothetical ecosystems. The greatest uncertainties in the estimations lie in the calculation of fluxes to and from the field layer. A parametrisation method based on multiple criteria, synthesising a wide range of empirical knowledge on ecosystem behaviour, proved to be useful both in the estimation of unknown parameters, to demonstrate model sensitivity, and to identify processes where our current knowledge is limited. The parameterizations derived from the study of the hypothetical systems were used to estimate site-specific carbon and water budgets for four ecosystems located within the Oskarshamn study-area. Measured soil respiration was used to calibrate the simulations. An analysis of the simulated carbon fluxes indicated that two of the ecosystems, namely the grassland and the spruce forest, were net sources of carbon dioxide, while the alder and the pine forest were net sinks of CO{sub 2}. In the former case, this was interpreted as a result of recent drainage of the organogenic soils and the concurrent increase in decomposition. The results from the study conformed rather well with results from a previous study on carbon budgets from the Oskarshamn study area.

  6. Modelling carbon and water flows in terrestrial ecosystems in the boreal zone - examples from Oskarshamn

    International Nuclear Information System (INIS)

    Karlberg, Louise; Gu stafsson, David; Jansson, Per-Erik

    2007-12-01

    Carbon budgets and mean residence times were estimated in four hypothetical ecosystems. The greatest uncertainties in the estimations lie in the calculation of fluxes to and from the field layer. A parametrisation method based on multiple criteria, synthesising a wide range of empirical knowledge on ecosystem behaviour, proved to be useful both in the estimation of unknown parameters, to demonstrate model sensitivity, and to identify processes where our current knowledge is limited. The parameterizations derived from the study of the hypothetical systems were used to estimate site-specific carbon and water budgets for four ecosystems located within the Oskarshamn study-area. Measured soil respiration was used to calibrate the simulations. An analysis of the simulated carbon fluxes indicated that two of the ecosystems, namely the grassland and the spruce forest, were net sources of carbon dioxide, while the alder and the pine forest were net sinks of CO 2 . In the former case, this was interpreted as a result of recent drainage of the organogenic soils and the concurrent increase in decomposition. The results from the study conformed rather well with results from a previous study on carbon budgets from the Oskarshamn study area

  7. Game animals and small terrestrial mammals - Suitable bioindicators for the pollution assessment in agrarian ecosystems

    Czech Academy of Sciences Publication Activity Database

    Vávrová, M.; Zlámalová Gargošová, H.; Šucman, E.; Večerek, V.; Kořínek, P.; Zukal, Jan; Zejda, Jan; Sebestiánová, N.; Kubištová, I.

    2003-01-01

    Roč. 12, č. 2 (2003), s. 165-172 ISSN 1018-4619 R&D Projects: GA AV ČR KSK6005114 Keywords : bioindicator s * agrarian ecosystems * pollution Subject RIV: EH - Ecology, Behaviour Impact factor: 0.325, year: 2003 http://www.psp-parlar.de/details_artikel.asp?tabelle=FEBArtikel&artikel_id=234&jahr=2003

  8. Responses of Terrestrial Herpetofauna to Persistent, Novel Ecosystems Resulting from Mountaintop Removal Mining

    Science.gov (United States)

    Jennifer M. Williams; Donald J. Brown; Petra B. Wood

    2017-01-01

    Mountaintop removal mining is a large-scale surface mining technique that removes entire floral and faunal communities, along with soil horizons located above coal seams. In West Virginia, the majority of this mining occurs on forested mountaintops. However, after mining ceases the land is typically reclaimed to grasslands and shrublands, resulting in novel ecosystems...

  9. Soil Heat Flow. Physical Processes in Terrestrial and Aquatic Ecosystems, Transport Processes.

    Science.gov (United States)

    Simpson, James R.

    These materials were designed to be used by life science students for instruction in the application of physical theory to ecosystem operation. Most modules contain computer programs which are built around a particular application of a physical process. Soil heat flow and the resulting soil temperature distributions have ecological consequences…

  10. Assessment of long-term effects of climate change on biodiversity and vulnerability of terrestrial ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Oene, H.; Berendse, F.; De Kovel, C.G.F. [Nature Consevation and Plant Ecology Group, Wageningen University, Wageningen (Netherlands); Alkemade, J.R.M.; Bakkenes, M.; Ihle, F. [National Institute of Public Health and the Environment RIVM, Bilthoven (Netherlands)

    1999-07-01

    The aim of this project was to analyze the effects of climatic change on plant species diversity and ecosystem functioning. The direct effects of climatic change on plant species diversity are analyzed using a species based probabilistic Model (EUROMOVE) that relates the probability of occurrence of ca 1400 European plant species to climatic variables as the mean temperature of the coldest month, the effective temperature sum, the annual precipitation, the annual potential and actual evapotranspiration, the length of the growing season, and the mean growing season temperature. The indirect effects of raised C0{sub 2} levels and increased temperatures on ecosystem functioning and the consequences of these indirect effects for plant diversity are analyzed by combining a mechanistic simulation model (NUCOM) with regression models. NUCOM predicts the effects of environmental changes on dominant plant species composition and ecosystem variables. The predicted ecosystem variables are linked to plant species diversity of subordinate species by regression models, using Ellenberg indices for N availability, soil acidity, soil moisture, and light intensity. With these two approaches, the consequences of climatic change scenarios (IPCC Baseline A, IPCC Stabilization 450) and N deposition scenarios (reduced, constant) are analyzed for Europe (EUROMOVE) and part of the Netherlands (NUCOM). The results showed that the direct effects of climatic change may have large impact on plant species diversity and distribution. The indirect effects of climatic change on plant diversity appeared minor but effects of changes in soil moisture are not included. Other environmental changes like eutrofication and human impact have large effect on ecosystem variables and plant species diversity. Reductions in nitrogen emission have a positive effect but take time to become apparent. 49 refs.

  11. Sensitivity of terrestrial ecosystems to elevated atmospheric CO{sub 2}: Comparisons of model simulation studies to CO{sub 2} effect

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Y. [Marine Biological Lab., Woods Hole, MA (United States)

    1995-06-01

    In the context of a project to compare terrestrial ecosystem models, the Vegetation/Ecosystem Modeling and Analysis Project (VEMAP), we have analyzed how three biogeochemistry models link plant growth to doubled atmospheric CO{sub 2}. A common set of input data was used to drive three biogeochemistry models, BIOME-BGC, CENTURY and TEM. For the continental United States the simulation results show that with doubled CO{sub 2}, NPP increased by 8.7%, 5.0% and 10.8% for TEM, CENTURY and BIOME-BGC, respectively. At the biome level the range of NPP estimates varied considerably among models. TEM-simulated enhancement of NPP ranged from 2% to 28%; CENTURY, from 2% to 9%; and BIOME-BGC, from 4% to 27%. A transect analysis across several biomes along a latitude at 41.5 N shows that the TEM-simulated CO{sub 2} enhancement of NPP ranged from 0% to 22%; CENTURY, from 1% to 10% and BIOME-BGC, from 1% to 63%. In this study, we have investigated the underlying mechanisms of the three models to reveal how increased CO{sub 2} affects photosynthesis rate, water using efficiency and nutrient cycles. The relative importance of these mechanisms in each of the three biogeochemistry models will be discussed.

  12. Environmental research programme. Ecological research. Annual report 1994. Urban-industrial landscapes, forests, agricultural landscapes, river and lake landscapes, terrestrial ecosystem research, environmental pollution and health

    International Nuclear Information System (INIS)

    1995-01-01

    In the annual report 1994 of the Federal Ministry of Research and Technology, the points of emphasis of the ecological research programme and their financing are discussed. The individual projects in the following subject areas are described in detail: urban-industrial landscapes, forests, agricultural landscapes, river and lake landscapes, other ecosystems and landscapes, terrestrial ecosystem research, environmental pollution and human health and cross-sectional activities in ecological research. (vhe) [de

  13. Trace metallic elements in Helix aspersa terrestrial snails of a semiarid ecosystem

    International Nuclear Information System (INIS)

    Gaso P, M.I.; Segovia, N.; Zarazua, G.; Montes, F.; Morton, O.; Armienta, M.A.; Hernandez, E.

    2001-01-01

    The concentration of some major elements and traces in soil samples and of Helix aspersa eatable terrestrial snails were analysed at the Radioactive Wastes Storage Center (CADER) and in other reference sites. The methodology includes the use of an atomic absorption spectrophotometer, an X-ray fluorescence equipment and an Icp-mass spectroscope. The concentrations of some toxic elements (Ba, Cd, Cr, Ni, Pb and V) in the soft tissue of the snails were greater than the toxic levels reported in the literature for such trace elements. The snails compared with another wild eatable foods present transfer coefficients soil-snail high relatively. (Author)

  14. Radiological bioconcentration factors for aquatic, terrestrial, and wetland ecosystems at the Savannah River site

    International Nuclear Information System (INIS)

    Friday, G.P.; Cummins, C.L.; Schwartzman, A.L.

    1996-01-01

    Since the early 1950s, the Savannah River Site (SRS) released over 50 radionuclides into the environment while producing nuclear defense materials. These releases directly exposed aquatic and terrestrial biota to ionizing radiation from surface water, soil, and sediment, and also indirectly by the ingestion of items in the food chain. As part of new missions to develop waste management strategies and identify cost-effective environmental restoration options, knowledge concerning the uptake and distribution of these radionuclides is essential. This report compiles and summarizes site-specific bioconcentration factors for selected radionuclides released at SRS

  15. Radiological bioconcentration factors for aquatic, terrestrial, and wetland ecosystems at the Savannah River site

    Energy Technology Data Exchange (ETDEWEB)

    Friday, G.P.; Cummins, C.L.; Schwartzman, A.L.

    1996-12-31

    Since the early 1950s, the Savannah River Site (SRS) released over 50 radionuclides into the environment while producing nuclear defense materials. These releases directly exposed aquatic and terrestrial biota to ionizing radiation from surface water, soil, and sediment, and also indirectly by the ingestion of items in the food chain. As part of new missions to develop waste management strategies and identify cost-effective environmental restoration options, knowledge concerning the uptake and distribution of these radionuclides is essential. This report compiles and summarizes site-specific bioconcentration factors for selected radionuclides released at SRS.

  16. Integration of Long term experiments on terrestrial ecosystem in AnaEE-France Research Infrastructure : concept and adding value

    Science.gov (United States)

    Chanzy, André; Chabbi, Abad; Houot, Sabine; Lafolie, François; Pichot, Christian; Raynal, Hélène; Saint-André, Laurent; Clobert, Jean; Greiveldinger, Lucile

    2015-04-01

    Continental ecosystems represent a critical zone that provide key ecological services to human populations like biomass production, that participate to the regulation of the global biogeochemical cycles and contribute and contribute to the maintenance of air and water quality. Global changes effects on continental ecosystems are likely to impact the fate of humanity, which is thus facing numerous challenges, such as an increasing demand for food and energy, competition for land and water use, or rapid climate warming. Hence, scientific progress in our understanding of the continental critical zone will come from studies that address how biotic and abiotic processes react to global changes. Long term experiments are required to take into account ecosystem inertia and feedback loops and to characterize trends and threshold in ecosystem dynamics. In France, 20 long-term experiments on terrestrial ecosystems are gathered within a single Research Infrastructure: ANAEE-France (http://www.anaee-s.fr), which is a part of AnaEE-Europe (http://www.anaee.com/). Each experiment consist in applying differentiated pressures on different plot over a long period (>20 years) representative of a range of management options. The originality of such infrastructure is a combination of experimental set up and long-term monitoring of simultaneous measurements of key ecosystem variables and parameters through a multi-disciplinary approach and replications of each treatment that improve the statistical strength of the results. The sites encompass gradients of climate conditions, ecosystem complexity and/or management, and can be used for calibration/validation of ecosystem functioning models as well as for the design of ecosystem management strategies. Gathering those experiments in a single research infrastructure is an important issue to enhance their visibility and increase the number of hosting scientific team by offering a range of services. These are: • Access to the ongoing long

  17. Nitrogen inputs accelerate phosphorus cycling rates across a wide variety of terrestrial ecosystems.

    Science.gov (United States)

    Marklein, Alison R; Houlton, Benjamin Z

    2012-02-01

    • Biologically essential elements--especially nitrogen (N) and phosphorus (P)--constrain plant growth and microbial functioning; however, human activities are drastically altering the magnitude and pattern of such nutrient limitations on land. Here we examine interactions between N and P cycles of P mineralizing enzyme activities (phosphatase enzymes) across a wide variety of terrestrial biomes. • We synthesized results from 34 separate studies and used meta-analysis to evaluate phosphatase activity with N, P, or N×P fertilization. • Our results show that N fertilization enhances phosphatase activity, from the tropics to the extra-tropics, both on plant roots and in bulk soils. By contrast, P fertilization strongly suppresses rates of phosphatase activity. • These results imply that phosphatase enzymes are strongly responsive to changes in local nutrient cycle conditions. We also show that plant phosphatases respond more strongly to fertilization than soil phosphatases. The tight coupling between N and P provides a mechanism for recent observations of N and P co-limitation on land. Moreover, our results suggest that terrestrial plants and microbes can allocate excess N to phosphatase enzymes, thus delaying the onset of single P limitation to plant productivity as can occur via human modifications to the global N cycle. © 2011 The Authors. New Phytologist © 2011 New Phytologist Trust.

  18. Ecosystem responses to reduced and oxidised nitrogen inputs in European terrestrial habitats

    Energy Technology Data Exchange (ETDEWEB)

    Stevens, C.J. [Department of Life Sciences, The Open University, Walton Hall, Milton Keynes, MK7 6AA (United Kingdom); Manning, P. [School of Agriculture Food and Rural Development, Newcastle University, Newcastle upon Tyne, Tyne and Wear, NE1 7RU (United Kingdom); Van den Berg, L.J.L. [Environment Department, University of York, Heslington, York, YO 5DD (United Kingdom); De Graaf, M.C.C. [University of Applied Sciences, HAS Den Bosch, PO BOX 90108, 5200 MA ' s-Hertogenbosch (Netherlands); Wieger Wamelink, G.W. [Alterra, Droevendaalsesteeg 3a, P.O. Box 47, 6700 AA Wageningen (Netherlands); Boxman, A.W.; Vergeer, P.; Lamers, L.P.M. [Department of Aquatic Ecology and Environmental Biology, University of Nijmegen, P.O. Box 9010, NL-6500 GL, Nijmegen (Netherlands); Bleeker, A. [Energy research Centre of the Netherlands, Petten, NH, 1755 ZG (Netherlands); Arroniz-Crespo, M. [Departamento de Biologia Vegetal II, Facultad de Farmacia, Universidad Complutense de Madrid, 28040, Madrid (Spain); Limpens, J. [Nature Conservation and Plant Ecology Group, Wageningen University, Bornsesteeg 69, 6708 PD Wageningen (Netherlands); Bobbink, R. [Ware Research Centre, Radboud University Nijmegen, PO Box 9010, 6500 GL Nijmegen (Netherlands); Dorland, E. [Staatsbosbeheer, PO Box 1300, 3970 BH, Driebergen (Netherlands)

    2011-03-15

    While it is well established that ecosystems display strong responses to elevated nitrogen deposition, the importance of the ratio between the dominant forms of deposited nitrogen (NHx and NOy) in determining ecosystem response is poorly understood. As large changes in the ratio of oxidised and reduced nitrogen inputs are occurring, this oversight requires attention. One reason for this knowledge gap is that plants experience a different NHx:NOy ratio in soil to that seen in atmospheric deposits because atmospheric inputs are modified by soil transformations, mediated by soil pH. Consequently species of neutral and alkaline habitats are less likely to encounter high NH4+ concentrations than species from acid soils. We suggest that the response of vascular plant species to changing ratios of NHx:NOy deposits will be driven primarily by a combination of soil pH and nitrification rates. Testing this hypothesis requires a combination of experimental and survey work in a range of systems.

  19. Impacts of urbanization on carbon balance in terrestrial ecosystems of the Southern United States

    International Nuclear Information System (INIS)

    Zhang Chi; Tian Hanqin; Chen, Guangsheng; Chappelka, Arthur; Xu Xiaofeng; Ren Wei; Hui Dafeng; Liu Mingliang; Lu Chaoqun; Pan, Shufen; Lockaby, Graeme

    2012-01-01

    Using a process-based Dynamic Land Ecosystem Model, we assessed carbon dynamics of urbanized/developed lands in the Southern United States during 1945–2007. The results indicated that approximately 1.72 (1.69–1.77) Pg (1P = 10 15 ) carbon was stored in urban/developed lands, comparable to the storage of shrubland or cropland in the region. Urbanization resulted in a release of 0.21 Pg carbon to the atmosphere during 1945–2007. Pre-urbanization vegetation type and time since land conversion were two primary factors determining the extent of urbanization impacts on carbon dynamics. After a rapid decline of carbon storage during land conversion, an urban ecosystem gradually accumulates carbon and may compensate for the initial carbon loss in 70–100 years. The carbon sequestration rate of urban ecosystem diminishes with time, nearly disappearing in two centuries after land conversion. This study implied that it is important to take urbanization effect into account for assessing regional carbon balance. - Highlights: ► A series of spatial and temporal urban/developed land maps were generated. ► Urbanization effects on regional carbon dynamics were studied with a process-based Dynamic Land Ecosystem Model (DLEM). ► Carbon storage of urban/developed land was comparable to that stored in cropland and shrubland in the Southern United States. ► Pre-urbanization vegetation type and time since land conversion were two primary factors determining the extent of urbanization impacts on carbon dynamics. ► Urbanization resulted in carbon emission, but established urban areas may gradually accumulate carbon over time. - Urbanization has resulted in carbon release to the atmosphere, but established urban areas may gradually accumulate carbon over time.

  20. Multi-proxy reconstructions and the power of integration across marine, terrestrial, and freshwater ecosystems. (Invited)

    Science.gov (United States)

    Black, B.

    2013-12-01

    Over the past decade, dendrochronology (tree-ring analysis) techniques have been increasingly applied to growth increments of various bivalve, fish, and coral species. In particular, the use of crossdating ensures that all increments in a dataset have assigned the correct calendar year of formation and that the resulting chronology is exactly placed in time. Such temporal alignment facilitates direct comparisons among chronologies that span diverse taxa and ecosystems, illustrating the pervasive, synchronizing influence of climate from alpine forests to the continental slope. Such an approach can be particularly beneficial to reconstructions in that each species captures climate signals from its unique 'perspective' of life history and habitat. For example, combinations of tree-ring data and chronologies for the long-lived bivalve Pacific geoduck (Panopea generosa) capture substantially more variance in regional sea surface temperatures than either proxy could explain alone. Just as importantly, networks of chronologies spanning multiple trophic levels can help identify climate variables critical to ecosystem functioning, which can then be targeted to generate most biologically relevant reconstructions possible. Along the west coast of North America, fish and bivalve chronologies in combination with records of seabird reproductive success indicate that winter sea-level pressure is closely associated with California Current productivity, which can be hind-cast over the past six centuries using coastal tree-ring chronologies. Thus, multiple proxies not only increase reconstruction skill, but also help isolate climate variables most closely linked to ecosystem structure and functioning.

  1. Ecosystem responses to reduced and oxidised nitrogen inputs in European terrestrial habitats

    International Nuclear Information System (INIS)

    Stevens, Carly J.; Manning, Pete; Berg, Leon J.L. van den; Graaf, Maaike C.C. de; Wamelink, G.W. Wieger; Boxman, Andries W.; Bleeker, Albert; Vergeer, Philippine; Arroniz-Crespo, Maria; Limpens, Juul; Lamers, Leon P.M.; Bobbink, Roland; Dorland, Edu

    2011-01-01

    While it is well established that ecosystems display strong responses to elevated nitrogen deposition, the importance of the ratio between the dominant forms of deposited nitrogen (NH x and NO y ) in determining ecosystem response is poorly understood. As large changes in the ratio of oxidised and reduced nitrogen inputs are occurring, this oversight requires attention. One reason for this knowledge gap is that plants experience a different NH x :NO y ratio in soil to that seen in atmospheric deposits because atmospheric inputs are modified by soil transformations, mediated by soil pH. Consequently species of neutral and alkaline habitats are less likely to encounter high NH 4 + concentrations than species from acid soils. We suggest that the response of vascular plant species to changing ratios of NH x :NO y deposits will be driven primarily by a combination of soil pH and nitrification rates. Testing this hypothesis requires a combination of experimental and survey work in a range of systems. - Changing ratios of NH x and NO y in deposition has important consequences for ecosystem function.

  2. Terrestrial ecosystem process model Biome-BGCMuSo v4.0: summary of improvements and new modeling possibilities

    Science.gov (United States)

    Hidy, Dóra; Barcza, Zoltán; Marjanović, Hrvoje; Zorana Ostrogović Sever, Maša; Dobor, Laura; Gelybó, Györgyi; Fodor, Nándor; Pintér, Krisztina; Churkina, Galina; Running, Steven; Thornton, Peter; Bellocchi, Gianni; Haszpra, László; Horváth, Ferenc; Suyker, Andrew; Nagy, Zoltán

    2016-12-01

    The process-based biogeochemical model Biome-BGC was enhanced to improve its ability to simulate carbon, nitrogen, and water cycles of various terrestrial ecosystems under contrasting management activities. Biome-BGC version 4.1.1 was used as a base model. Improvements included addition of new modules such as the multilayer soil module, implementation of processes related to soil moisture and nitrogen balance, soil-moisture-related plant senescence, and phenological development. Vegetation management modules with annually varying options were also implemented to simulate management practices of grasslands (mowing, grazing), croplands (ploughing, fertilizer application, planting, harvesting), and forests (thinning). New carbon and nitrogen pools have been defined to simulate yield and soft stem development of herbaceous ecosystems. The model version containing all developments is referred to as Biome-BGCMuSo (Biome-BGC with multilayer soil module; in this paper, Biome-BGCMuSo v4.0 is documented). Case studies on a managed forest, cropland, and grassland are presented to demonstrate the effect of model developments on the simulation of plant growth as well as on carbon and water balance.

  3. Effects of long-range transported acidification on the bio-diversity in terrestrial ecosystems; Effekter av langtransporterte forsuringer paa biodiversitet i terrestriske oekosystemer

    Energy Technology Data Exchange (ETDEWEB)

    Hoeiland, K [Oslo Univ. (Norway)

    1996-01-01

    The conference paper deals with the environmental effects of long-range transported pollutants on the biodiversity in the terrestrial ecosystems. The paper discusses different chemical substances existing in the atmosphere and their influence on vegetation together with the effects on biodiversity from acidification. 4 refs.

  4. Ring-testing and field-validation of a terrestrial model ecosystem TME) - An instrument for testing potentially harmful substances: conceptual approach and study design.

    NARCIS (Netherlands)

    Knacker, T.; van Gestel, C.A.M.; Jones, S.E.; Soares, A.M.V.M.; Schallnass, H.-J.; Förster, B.; Edwards, C.A.

    2004-01-01

    During spring and summer 1999 a ring-test and field-validation study with an open, intact Terrestrial Model Ecosystem (TME) was conducted at four different European sites (Amsterdam, The Netherlands; Bangor, U.K.; Coimbra, Portugal; Flörsheim, Germany). The objective of the study was to establish a

  5. Ring-testing and field-validation of a terrestrial model ecosystem (TME) - An instrument for testing potentially harmful substances: effects of carbendazim on enchytraeids.

    NARCIS (Netherlands)

    Moser, T.; van Gestel, C.A.M.; Jones, S.E.; Koolhaas, J.E.; Rodrigues, J.M.L.; Römbke, J.

    2004-01-01

    The effects of the fungicide carbendazim (applied in the formulation Derosal®) on enchytraeids were determined in Terrestrial Model Ecosystem (TME) tests and field-validation studies. TMEs consisted of intact soil columns (diameter 17.5 cm; length 40 cm) taken from a grassland or, in one case, from

  6. Ring-testing and field-validation of a terrestrial model ecosystem - An instrument for testing potentially harmful substances: effects of carbendazim on nutrient cycling.

    NARCIS (Netherlands)

    van Gestel, C.A.M.; Koolhaas, J.E.; Schallnass, H.-J.; Rodrigues, J.M.L.; Jones, S.E.

    2004-01-01

    The effect of the fungicide carbendazim (applied in the formulation Derosal®) on nutrient cycling in soil was determined in Terrestrial Model Ecosystem (TME) tests and corresponding field-validation studies, which were performed in four different countries (United Kingdom, Germany, Portugal, and The

  7. Ring-testing and field-validation of a terrestrial model ecosystem (TME) - An instrument for testing potentially harmful substances: effects of carbendazim on soil microarthropod communities.

    NARCIS (Netherlands)

    Koolhaas, J.E.; van Gestel, C.A.M.; Römbke, J.; Soares, A.M.V.M.; Jones, S.E.

    2004-01-01

    The effects of the fungicide carbendazim (applied in the formulation Derosal) on soil microarthropod communities was determined in three Terrestrial Model Ecosystem (TME) tests and a field-validation study for a period of 16 weeks after application. TMEs consisted of intact soil columns (diameter

  8. The use of the multivariate Principal Response Curve (PRC) for community analysis: a case study on the effects of carbendazim on enchytraeids in Terrestrial Model Ecosystems (TME).

    NARCIS (Netherlands)

    Moser, T.; Römbke, J.; Schallnass, H.-J.; van Gestel, C.A.M.

    2007-01-01

    The effects of the fungicide carbendazim (formulation Derosal®) on enchytraeids were determined in Terrestrial Model Ecosystem (TME) tests. TMEs consisted of intact soil columns (diameter 17.5 cm; length 40 cm) taken from three grassland sites (Amsterdam (The Netherlands), Bangor (Wales, England)

  9. Ring-testing and field-validation of a terrestrial model ecosystem (TME) - An instrument for testing potentially harmful substances: effects of carbendazim on nematodes.

    NARCIS (Netherlands)

    Moser, T.; Schallnass, H.-J.; Jones, S.E.; van Gestel, C.A.M.; Koolhaas, J.E.; Rodrigues, J.M.L.; Römbke, J.

    2004-01-01

    The effects of the fungicide carbendazim (applied in the formulation Derosal®) on nematodes was determined in Terrestrial Model Ecosystem (TME) tests and field-validation studies. TMEs consisted of intact soil columns (diameter 17.5 cm; length 40 cm) taken from a grassland or, in one case, from an

  10. Estimating radionuclide transfer to wild species-data requirements and availability for terrestrial ecosystems

    International Nuclear Information System (INIS)

    Beresford, N A; Broadley, M R; Howard, B J; Barnett, C L; White, P J

    2004-01-01

    Assessment of the transfer of radionuclides to wild species is an important component in the estimation of predicted doses to biota. Reviews of available data for the many potential radionuclide-biota combinations which may be required for environmental assessments highlight many data gaps for terrestrial species. Here, we discuss different approaches which have been suggested to compensate for these data gaps. All of the reviewed approaches have merit; however, there is a requirement for transparency in methodology and data provenance which in some instances is currently missing. Furthermore, there is a need to validate the various methodologies to enable their use with confidence. The requirements of improving our ability to predict radionuclide transfer to wild species are discussed and recommendations made

  11. Habitats at Risk. Global Warming and Species Loss in Globally Significant Terrestrial Ecosystems

    International Nuclear Information System (INIS)

    Malcolm, J.R.; Liu, Canran; Miller, L.B.; Allnutt, T.; Hansen, L.

    2002-02-01

    In this study, a suite of models of global climate and vegetation change is used to investigate three important global warming-induced threats to the terrestrial Global 200 ecoregions: (1) Invasions by new habitat types (and corresponding loss of original habitat types); (2) Local changes of habitat types; (3) High rates of required species migration. Seven climate models (general circulation models or GCMs) and two vegetation models (BIOME3 and MAPSS) were used to produce 14 impact scenarios under the climate associated with a doubling of atmospheric CO2 concentrations, which is expected to occur in less than 100 years. Previous analyses indicated that most of the variation among the impact scenarios was attributable to the particular vegetation model used, hence the authors provide results separately for the two models. The models do not provide information on biodiversity per se, but instead simulate current and future potential distributions of major vegetation types (biomes) such as tundra and broadleaf tropical rain forest

  12. Optimization of Terrestrial Ecosystem Model Parameters Using Atmospheric CO2 Concentration Data With the Global Carbon Assimilation System (GCAS)

    Science.gov (United States)

    Chen, Zhuoqi; Chen, Jing M.; Zhang, Shupeng; Zheng, Xiaogu; Ju, Weiming; Mo, Gang; Lu, Xiaoliang

    2017-12-01

    The Global Carbon Assimilation System that assimilates ground-based atmospheric CO2 data is used to estimate several key parameters in a terrestrial ecosystem model for the purpose of improving carbon cycle simulation. The optimized parameters are the leaf maximum carboxylation rate at 25°C (Vmax25), the temperature sensitivity of ecosystem respiration (Q10), and the soil carbon pool size. The optimization is performed at the global scale at 1° resolution for the period from 2002 to 2008. The results indicate that vegetation from tropical zones has lower Vmax25 values than vegetation in temperate regions. Relatively high values of Q10 are derived over high/midlatitude regions. Both Vmax25 and Q10 exhibit pronounced seasonal variations at middle-high latitudes. The maxima in Vmax25 occur during growing seasons, while the minima appear during nongrowing seasons. Q10 values decrease with increasing temperature. The seasonal variabilities of Vmax25 and Q10 are larger at higher latitudes. Optimized Vmax25 and Q10 show little seasonal variabilities at tropical regions. The seasonal variabilities of Vmax25 are consistent with the variabilities of LAI for evergreen conifers and broadleaf evergreen forests. Variations in leaf nitrogen and leaf chlorophyll contents may partly explain the variations in Vmax25. The spatial distribution of the total soil carbon pool size after optimization is compared favorably with the gridded Global Soil Data Set for Earth System. The results also suggest that atmospheric CO2 data are a source of information that can be tapped to gain spatially and temporally meaningful information for key ecosystem parameters that are representative at the regional and global scales.

  13. A hierarchical analysis of terrestrial ecosystem model Biome-BGC: Equilibrium analysis and model calibration

    Energy Technology Data Exchange (ETDEWEB)

    Thornton, Peter E [ORNL; Wang, Weile [ORNL; Law, Beverly E. [Oregon State University; Nemani, Ramakrishna R [NASA Ames Research Center

    2009-01-01

    The increasing complexity of ecosystem models represents a major difficulty in tuning model parameters and analyzing simulated results. To address this problem, this study develops a hierarchical scheme that simplifies the Biome-BGC model into three functionally cascaded tiers and analyzes them sequentially. The first-tier model focuses on leaf-level ecophysiological processes; it simulates evapotranspiration and photosynthesis with prescribed leaf area index (LAI). The restriction on LAI is then lifted in the following two model tiers, which analyze how carbon and nitrogen is cycled at the whole-plant level (the second tier) and in all litter/soil pools (the third tier) to dynamically support the prescribed canopy. In particular, this study analyzes the steady state of these two model tiers by a set of equilibrium equations that are derived from Biome-BGC algorithms and are based on the principle of mass balance. Instead of spinning-up the model for thousands of climate years, these equations are able to estimate carbon/nitrogen stocks and fluxes of the target (steady-state) ecosystem directly from the results obtained by the first-tier model. The model hierarchy is examined with model experiments at four AmeriFlux sites. The results indicate that the proposed scheme can effectively calibrate Biome-BGC to simulate observed fluxes of evapotranspiration and photosynthesis; and the carbon/nitrogen stocks estimated by the equilibrium analysis approach are highly consistent with the results of model simulations. Therefore, the scheme developed in this study may serve as a practical guide to calibrate/analyze Biome-BGC; it also provides an efficient way to solve the problem of model spin-up, especially for applications over large regions. The same methodology may help analyze other similar ecosystem models as well.

  14. Transfer of radionuclides by terrestrial food products from semi-natural ecosystems to humans

    International Nuclear Information System (INIS)

    Howard, B.J.

    1996-01-01

    The potential radiological significance of radionuclide transfer to humans via foodstuffs derived from semi-natural ecosystems has become apparent since the Chernobyl accident. Foodchain models developed before this time usually did not take such transfers into account. The processes leading to contamination of food in these environments are complex and current understanding of the transfer mechanisms is incomplete. For these reasons the approach adopted in Chapter 3 is to represent, by means of aggregated parameters, the empirical relationships between ground deposits and concentration in the food product. 107 refs, 2 figs, 9 tabs

  15. Behavior of pyrophite shrubs in mediterranean terrestrial ecosystems (i): Population and reproductive model.

    Science.gov (United States)

    Usó-Doménech, Josep-Lluis; Nescolarde-Selva, Josué-Antonio; Lloret-Climent, Miguel; González-Franco, Lucía

    2018-03-01

    The mathematical submodel ULEX is used to study the dynamic behavior of the green, floral and woody biomass of the main pyrophite shrub species, the gorse (Ulex parviflorus Pourret), and its relationship with other shrub species, typical of a Mediterranean ecosystem. The focus are the ecological conditions of post-fire stage growth, and its efficacy as a protective cover against erosion processes in the short, medium and long term, both in normal conditions and at the limits of desertification conditions. The model sets a target to observe the behavior and to anticipate and consequently intervene with adequate protection, restoration and management measures. Copyright © 2018 Elsevier Inc. All rights reserved.

  16. Ecosystem Warming Affects CO2 Flux in an Agricultural Soil

    Science.gov (United States)

    Global warming seems likely based on present-day climate predictions. Our objective was to characterize and quantify the interactive effects of ecosystem warming (i.e., canopy temperature, TS), soil moisture content ('S) and microbial biomass (BM: bacteria, fungi) on the intra-row soil CO2 flux (FS)...

  17. How does whole ecosystem warming of a peatland affect methane production and consumption?

    Science.gov (United States)

    Hopple, A.; Brunik, K.; Keller, J.; Pfeifer-Meister, L.; Woerndle, G.; Zalman, C.; Hanson, P.; Bridgham, S. D.

    2017-12-01

    Peatlands are among Earth's most important terrestrial ecosystems due to their massive soil carbon (C) stores and significant release of methane (CH4) into the atmosphere. Methane has a sustained-flux global warming potential 45-times greater than carbon dioxide (CO2), and the accuracy of Earth system model projections relies on our mechanistic understanding of peatland CH4 cycling in the context of environmental change. The objective of this study was to determine, under in situ conditions, how heating of the peat profile affects ecosystem-level anaerobic C cycling. We assessed the response of CO2 and CH4 production, as well as the anaerobic oxidation of CH4 (AOM), in a boreal peatland following 13 months of deep peat heating (DPH) and 16 months of subsequent whole-ecosystem warming (surface and deep heating; WEW) as part of the Spruce and Peatland Responses Under Changing Environments (SPRUCE) project in northern Minnesota, USA. The study uses a regression-based experimental design including 5 temperature treatments that warmed the entire 2 m peat profile from 0 to +9 °C above ambient temperature. Soil cores were collected at multiple depths (25-200 cm) from each experimental chamber at the SPRUCE site and anaerobically incubated at in situ temperatures for 1-2 weeks. Methane and CO2 production in surface peat were positively correlated with elevated temperature, but no consistent temperature response was found at depth (75-200 cm) following DPH. However, during WEW, we observed significant increases in both surface and deep peat methanogenesis with increasing temperature. Surface peat had greater CH4 production rates than deeper peat, implying that the increased CH4 emissions observed in the field were largely driven by surface peat warming. The CO2:CH4 ratio was inversely correlated with temperature across all depths following 16 months of WEW, indicating that the entire peat profile is becoming more methanogenic with warming. We also observed AOM throughout

  18. Partition of some key regulating services in terrestrial ecosystems: Meta-analysis and review

    Energy Technology Data Exchange (ETDEWEB)

    Viglizzo, E.F., E-mail: evigliz@cpenet.com.ar [INTA, EEA Anguil, Grupo de Investigaciones en Gestión Ambiental (GIGA), Av. Spinetto 785, 6300 Santa Rosa, La Pampa (Argentina); INCITAP-CONICET, Ruta 35, km 335, 6300 Santa Rosa, La Pampa (Argentina); UNLPam, Facultad de Ciencias Exactas y Naturales, Av. Uruguay 151, 6300 Santa Rosa, La Pampa (Argentina); Jobbágy, E.G. [CONICET, Andes 950, 5700 San Luis, San Luis (Argentina); Grupo de Estudios Ambientales IMASL, Ejército de los, Andes 950, 5700 San Luis, San Luis (Argentina); Ricard, M.F. [INCITAP-CONICET, Ruta 35, km 335, 6300 Santa Rosa, La Pampa (Argentina); UNLPam, Facultad de Ciencias Exactas y Naturales, Av. Uruguay 151, 6300 Santa Rosa, La Pampa (Argentina); Paruelo, J.M. [Laboratorio de Análisis Regional y Teledetección, Departamento de Métodos Cuantitativos Sistemas de información, Facultad de Agronomía and IFEVA, Universidad de Buenos Aires and CONICET, Av. San Martín 4453, 1417 Buenos Aires (Argentina)

    2016-08-15

    Our knowledge about the functional foundations of ecosystem service (ES) provision is still limited and more research is needed to elucidate key functional mechanisms. Using a simplified eco-hydrological scheme, in this work we analyzed how land-use decisions modify the partition of some essential regulatory ES by altering basic relationships between biomass stocks and water flows. A comprehensive meta-analysis and review was conducted based on global, regional and local data from peer-reviewed publications. We analyzed five datasets comprising 1348 studies and 3948 records on precipitation (PPT), aboveground biomass (AGB), AGB change, evapotranspiration (ET), water yield (WY), WY change, runoff (R) and infiltration (I). The conceptual framework was focused on ES that are associated with the ecological functions (e.g., intermediate ES) of ET, WY, R and I. ES included soil protection, carbon sequestration, local climate regulation, water-flow regulation and water recharge. To address the problem of data normality, the analysis included both parametric and non-parametric regression analysis. Results demonstrate that PPT is a first-order biophysical factor that controls ES release at the broader scales. At decreasing scales, ES are partitioned as result of PPT interactions with other biophysical and anthropogenic factors. At intermediate scales, land-use change interacts with PPT modifying ES partition as it the case of afforestation in dry regions, where ET and climate regulation may be enhanced at the expense of R and water-flow regulation. At smaller scales, site-specific conditions such as topography interact with PPT and AGB displaying different ES partition formats. The probable implications of future land-use and climate change on some key ES production and partition are discussed. - Highlights: • The partition of regulatory services in ecosystems poses a major policy challenge. • We examined how partitions occur at the hydrosphere

  19. Partition of some key regulating services in terrestrial ecosystems: Meta-analysis and review

    International Nuclear Information System (INIS)

    Viglizzo, E.F.; Jobbágy, E.G.; Ricard, M.F.; Paruelo, J.M.

    2016-01-01

    Our knowledge about the functional foundations of ecosystem service (ES) provision is still limited and more research is needed to elucidate key functional mechanisms. Using a simplified eco-hydrological scheme, in this work we analyzed how land-use decisions modify the partition of some essential regulatory ES by altering basic relationships between biomass stocks and water flows. A comprehensive meta-analysis and review was conducted based on global, regional and local data from peer-reviewed publications. We analyzed five datasets comprising 1348 studies and 3948 records on precipitation (PPT), aboveground biomass (AGB), AGB change, evapotranspiration (ET), water yield (WY), WY change, runoff (R) and infiltration (I). The conceptual framework was focused on ES that are associated with the ecological functions (e.g., intermediate ES) of ET, WY, R and I. ES included soil protection, carbon sequestration, local climate regulation, water-flow regulation and water recharge. To address the problem of data normality, the analysis included both parametric and non-parametric regression analysis. Results demonstrate that PPT is a first-order biophysical factor that controls ES release at the broader scales. At decreasing scales, ES are partitioned as result of PPT interactions with other biophysical and anthropogenic factors. At intermediate scales, land-use change interacts with PPT modifying ES partition as it the case of afforestation in dry regions, where ET and climate regulation may be enhanced at the expense of R and water-flow regulation. At smaller scales, site-specific conditions such as topography interact with PPT and AGB displaying different ES partition formats. The probable implications of future land-use and climate change on some key ES production and partition are discussed. - Highlights: • The partition of regulatory services in ecosystems poses a major policy challenge. • We examined how partitions occur at the hydrosphere

  20. Bounding uncertainty in volumetric geometric models for terrestrial lidar observations of ecosystems.

    Science.gov (United States)

    Paynter, Ian; Genest, Daniel; Peri, Francesco; Schaaf, Crystal

    2018-04-06

    Volumetric models with known biases are shown to provide bounds for the uncertainty in estimations of volume for ecologically interesting objects, observed with a terrestrial laser scanner (TLS) instrument. Bounding cuboids, three-dimensional convex hull polygons, voxels, the Outer Hull Model and Square Based Columns (SBCs) are considered for their ability to estimate the volume of temperate and tropical trees, as well as geomorphological features such as bluffs and saltmarsh creeks. For temperate trees, supplementary geometric models are evaluated for their ability to bound the uncertainty in cylinder-based reconstructions, finding that coarser volumetric methods do not currently constrain volume meaningfully, but may be helpful with further refinement, or in hybridized models. Three-dimensional convex hull polygons consistently overestimate object volume, and SBCs consistently underestimate volume. Voxel estimations vary in their bias, due to the point density of the TLS data, and occlusion, particularly in trees. The response of the models to parametrization is analysed, observing unexpected trends in the SBC estimates for the drumlin dataset. Establishing that this result is due to the resolution of the TLS observations being insufficient to support the resolution of the geometric model, it is suggested that geometric models with predictable outcomes can also highlight data quality issues when they produce illogical results.

  1. Novel approaches to study climate change effects on terrestrial ecosystems in the field

    DEFF Research Database (Denmark)

    Beier, C.; Emmett, B.; Gundersen, P.

    2004-01-01

    mimicked the way climate change, caused by increased cloudiness and increased greenhouse gas emissions, alters the heat balance of ecosystems. Drought conditions were created by automatically covering the vegetation with transparent curtains during rain events over a 2-5-month period. The experimental...... that the approach minimizes unintended artifacts with respect to water balance, moisture conditions, and light, while causing a small but significant reduction in wind speed by the curtains. Temperature measurements demonstrated that the edge effects associated with the treatments were small. Our method provides...... approach has been evaluated at four European sites across a climate gradient. All sites were dominated (more than 50%) by shrubs of the ericaceous family. Within each site, replicated 4-m X 5-m plots were established for control, warming, and drought treatments and the effect on climate variables recorded...

  2. Dynamic of biogeochemical selenium cycle in terrestrial ecosystems: retention and reactivity in soil; role of vegetation

    International Nuclear Information System (INIS)

    Di Tullo, Pamela

    2015-01-01

    This work was performed in the frame of the safety assessment program prior to the possible construction of an underground repository for nuclear waste (HAVL). To consolidate risk assessment models associated to a potential 79 Se biosphere contamination, biogeochemistry of stable selenium was investigated, aiming firstly to highlight the dynamics of Se cycling in a forest ecosystem, in terms of inventories and annual fluxes. Consequently to these first results, which suggest a clay role of soil and its organic pool in the global Se cycle, two studies based on the use of isotopically enriched tracers were further carried out in order to clarify the processes involved in (i) Se retention and reactivity in soils and (ii) incorporation of inorganic Se within organic pool of vegetal biomass. (author) [fr

  3. Understanding Late Triassic low latitude terrestrial ecosystems: new insights from the Colorado Plateau Coring Project (CPCP)

    Science.gov (United States)

    Irmis, R. B.; Olsen, P. E.; Parker, W.; Rasmussen, C.; Mundil, R.; Whiteside, J. H.

    2017-12-01

    The Chinle Formation of southwestern North America is a key paleontological archive of low paleolatitude non-marine ecosystems that existed during the Late Triassic hothouse world. These strata were deposited at 5-15°N latitude, and preserve extensive plant, invertebrate, and vertebrate fossil assemblages, including early dinosaurs; these organisms lived in an unpredictably fluctuating semi-arid to arid environment with very high atmospheric pCO2. Despite this well-studied fossil record, a full understanding of these ecosystems and their integration with other fossil assemblages globally has been hindered by a poor understanding of the Chinle Formation's age, duration, and sedimentation rates. Recently, the CPCP recovered a 520m continuous core through this formation from the northern portion of Petrified Forest National Park (PEFO) in northern Arizona, USA. This core has provided a plethora of new radioisotopic and magnetostratigraphic data from fresh, unweathered samples in unambiguous stratigraphic superposition. These constraints confirm that virtually all fossil-bearing horizons in Chinle outcrops in the vicinity of PEFO are Norian in age. Furthermore, they indicate that the palynomorph zone II and Adamanian vertebrate biozone are at least six million years long, whereas the overlying palynomorph zone III and Revueltian vertebrate biozone persisted for at least five million years, with the boundary between 216-214 Ma. This confirms that the rich late Adamanian-early Revueltian vertebrate fossil assemblages, where dinosaurs are exclusively rare, small-bodied carnivorous theropods, are contemporaneous with higher latitude assemblages in Europe, South America, and Africa where large-bodied herbivorous sauropodomorph dinosaurs are common. The age constraints also confirm that several palynomorph biostratigraphic ranges in the Chinle Formation differ from those of the same taxa in eastern North American (Newark Supergroup) and Europe. These data are consistent

  4. Responses of terrestrial herpetofauna to persistent, novel ecosystems resulting from mountaintop removal mining

    Science.gov (United States)

    Williams, Jennifer M.; Brown, Donald J.; Wood, Petra B.

    2017-01-01

    Mountaintop removal mining is a large-scale surface mining technique that removes entire floral and faunal communities, along with soil horizons located above coal seams. In West Virginia, the majority of this mining occurs on forested mountaintops. However, after mining ceases the land is typically reclaimed to grasslands and shrublands, resulting in novel ecosystems. In this study, we examined responses of herpetofauna to these novel ecosystems 10–28 y postreclamation. We quantified differences in species-specific habitat associations, (sub)order-level abundances, and habitat characteristics in four habitat types: reclaimed grassland, reclaimed shrubland, forest fragments in mined areas, and nonmined intact forest. Habitat type accounted for 33.2% of the variation in species-specific captures. With few exceptions, forest specialists were associated with intact forest and fragmented forest sites, while habitat generalists were either associated with grassland and shrubland sites or were distributed among all habitat types. At the (sub)order level, salamander (Order Urodela) captures were highest at fragmented and intact forest sites, frog and toad (Order Anura) captures were lowest at intact forest sites, and snake (Suborder Serpentes) captures were highest at shrubland sites. Habitat type was a strong predictor for estimated total abundance of urodeles, but not for anurans or snakes. Tree stem densities in grasslands differed from the other three habitat types, and large trees (>38 cm diameter at breast height) were only present at forest sites. Overstory vegetation cover was greater in forested than in reclaimed habitat types. Ground cover in reclaimed grasslands was distinct from forest treatments with generally less woody debris and litter cover and more vegetative cover. It is important to consider the distributions of habitat specialists of conservation concern when delineating potential mountaintop mine sites, as these sites will likely contain unsuitable

  5. Metagenomic insights into S(0 precipitation in a terrestrial subsurface lithoautotrophic ecosystem

    Directory of Open Access Journals (Sweden)

    Trinity eHamilton

    2015-01-01

    Full Text Available The Frasassi and Acquasanta Terme cave systems in Italy host isolated lithoautotrophic ecosystems characterized by sulfur-oxidizing biofilms with up to 50% S(0 by mass. The net contributions of microbial taxa in the biofilms to production and consumption of S(0 are poorly understood and have implications for understanding the formation of geological sulfur deposits as well as the ecological niches of sulfur-oxidizing autotrophs. Filamentous Epsilonproteobacteria are among the principal biofilm architects in Frasassi and Acquasanta Terme streams, colonizing high-sulfide, low-oxygen niches relative to other major biofilm-forming populations. Metagenomic sequencing of eight biofilm samples indicated the presence of diverse and abundant Epsilonproteobacteria. Populations of Sulfurovum-like organisms were the most abundant Epsilonproteobacteria regardless of differences in biofilm morphology, temperature, or water chemistry. After assembling and binning the metagenomic data, we retrieved four nearly-complete genomes of Sulfurovum-like organisms as well as a Sulfuricurvum spp. Analyses of the binned and assembled metagenomic data indicate that the Epsilonproteobacteria are autotrophic and therefore provide organic carbon to the isolated subsurface ecosystem. Multiple homologs of sulfide-quinone oxidoreductase (Sqr, together with incomplete or absent Sox pathways, suggest that cave Sulfurovum-like Epsilonproteobacteria oxidize sulfide incompletely to S(0 using either O2 or nitrate as a terminal electron acceptor, consistent with previous evidence that they are most successful in niches with high dissolved sulfide to oxygen ratios. In contrast, we recovered homologs of the complete complement of Sox proteins affiliated Gammaproteobacteria and with less abundant Sulfuricurvum spp. and Arcobacter spp., suggesting that these populations are capable of the complete oxidation of sulfide to sulfate. These and other genomic data presented here offer new clues

  6. The age and diversification of terrestrial New World ecosystems through Cretaceous and Cenozoic time.

    Science.gov (United States)

    Graham, Alan

    2011-03-01

    Eight ecosystems that were present in the Cretaceous about 100 Ma (million years ago) in the New World eventually developed into the 12 recognized for the modern Earth. Among the forcing mechanisms that drove biotic change during this interval was a decline in global temperatures toward the end of the Cretaceous, augmented by the asteroid impact at 65 Ma and drainage of seas from continental margins and interiors; separation of South America from Africa beginning in the south at ca. 120 Ma and progressing northward until completed 90-100 Ma; the possible emission of 1500 gigatons of methane and CO(2) attributed to explosive vents in the Norwegian Sea at ca. 55 Ma, resulting in a temperature rise of 5°-6°C in an already warm world; disruption of the North Atlantic land bridge at ca. 45 Ma at a time when temperatures were falling; rise of the Andes Mountains beginning at ca. 40 Ma; opening of the Drake Passage between South America and Antarctica at ca. 32 Ma with formation of the cold Humboldt at ca. 30 Ma; union of North and South America at ca. 3.5 Ma; and all within the overlay of evolutionary processes. These processes generated a sequence of elements (e.g., species growing in moist habitats within an overall dry environment; gallery forests), early versions (e.g., mangrove communities without Rhizophora until the middle Eocene), and essentially modern versions of present-day New World ecosystems. As a first approximation, the fossil record suggests that early versions of aquatic communities (in the sense of including a prominent angiosperm component) appeared early in the Middle to Late Cretaceous, the lowland neotropical rainforest at 64 Ma (well developed by 58-55 Ma), shrubland/chaparral-woodland-savanna and grasslands around the middle Miocene climatic optimum at ca. 15-13 Ma, deserts in the middle Miocene/early Pliocene at ca. 10 Ma, significant tundra at ca. 7-5 Ma, and alpine tundra (páramo) shortly thereafter when cooling temperatures were augmented

  7. Comparing the Influence of Wildfire and Prescribed Burns on Watershed Nitrogen Biogeochemistry Using 15N Natural Abundance in Terrestrial and Aquatic Ecosystem Components

    Science.gov (United States)

    Stephan, Kirsten; Kavanagh, Kathleen L.; Koyama, Akihiro

    2015-01-01

    We evaluated differences in the effects of three low-severity spring prescribed burns and four wildfires on nitrogen (N) biogeochemistry in Rocky Mountain headwater watersheds. We compared paired (burned/unburned) watersheds of four wildfires and three spring prescribed burns for three growing seasons post-fire. To better understand fire effects on the entire watershed ecosystem, we measured N concentrations and δ15N in both the terrestrial and aquatic ecosystems components, i.e., soil, understory plants in upland and riparian areas, streamwater, and in-stream moss. In addition, we measured nitrate reductase activity in foliage of Spiraea betulifolia, a dominant understory species. We found increases of δ15N and N concentrations in both terrestrial and aquatic ecosystem N pools after wildfire, but responses were limited to terrestrial N pools after prescribed burns indicating that N transfer from terrestrial to aquatic ecosystem components did not occur in low-severity prescribed burns. Foliar δ15N differed between wildfire and prescribed burn sites; the δ15N of foliage of upland plants was enriched by 2.9 ‰ (difference between burned and unburned watersheds) in the first two years after wildfire, but only 1.3 ‰ after prescribed burns. In-stream moss δ15N in wildfire-burned watersheds was enriched by 1.3 ‰, but there was no response by moss in prescription-burned watersheds, mirroring patterns of streamwater nitrate concentrations. S. betulifolia showed significantly higher nitrate reductase activity two years after wildfires relative to corresponding unburned watersheds, but no such difference was found after prescribed burns. These responses are consistent with less altered N biogeochemistry after prescribed burns relative to wildfire. We concluded that δ15N values in terrestrial and aquatic plants and streamwater nitrate concentrations after fire can be useful indicators of the magnitude and duration of fire effects and the fate of post

  8. Nitrogen Availability Dampens the Positive Impacts of CO2 Fertilization on Terrestrial Ecosystem Carbon and Water Cycles

    Science.gov (United States)

    He, Liming; Chen, Jing M.; Croft, Holly; Gonsamo, Alemu; Luo, Xiangzhong; Liu, Jane; Zheng, Ting; Liu, Ronggao; Liu, Yang

    2017-11-01

    The magnitude and variability of the terrestrial CO2 sink remain uncertain, partly due to limited global information on ecosystem nitrogen (N) and its cycle. Without N constraint in ecosystem models, the simulated benefits from CO2 fertilization and CO2-induced increases in water use efficiency (WUE) may be overestimated. In this study, satellite observations of a relative measure of chlorophyll content are used as a proxy for leaf photosynthetic N content globally for 2003-2011. Global gross primary productivity (GPP) and evapotranspiration are estimated under elevated CO2 and N-constrained model scenarios. Results suggest that the rate of global GPP increase is overestimated by 85% during 2000-2015 without N limitation. This limitation is found to occur in many tropical and boreal forests, where a negative leaf N trend indicates a reduction in photosynthetic capacity, thereby suppressing the positive vegetation response to enhanced CO2 fertilization. Based on our carbon-water coupled simulations, enhanced CO2 concentration decreased stomatal conductance and hence increased WUE by 10% globally over the 1982 to 2015 time frame. Due to increased anthropogenic N application, GPP in croplands continues to grow and offset the weak negative trend in forests due to N limitation. Our results also show that the improved WUE is unlikely to ease regional droughts in croplands because of increases in evapotranspiration, which are associated with the enhanced GPP. Although the N limitation on GPP increase is large, its associated confidence interval is still wide, suggesting an urgent need for better understanding and quantification of N limitation from satellite observations.

  9. Role of brown bears (Ursus arctos) in the flow of marine nitrogen into a terrestrial ecosystem.

    Science.gov (United States)

    Hilderbrand, G V; Hanley, Thomas A; Robbins, Charles T; Schwartz, C C

    1999-12-01

    We quantified the amount, spatial distribution, and importance of salmon (Oncorhynchus spp.)-derived nitrogen (N) by brown bears (Ursus arctos) on the Kenai Peninsula, Alaska. We tested and confirmed the hypothesis that the stable isotope signature (δ 15 N) of N in foliage of white spruce (Picea glauca) was inversely proportional to the distance from salmon-spawning streams (r=-0.99 and Pbrown bears, relative to their distance from a stream, were highly correlated with δ 15 N depletion of foliage across the same gradient (r=-0.98 and -0.96 and Pbrown bears were 37.2±2.9 kg/year per bear (range 23.1-56.3), of which 96% (35.7±2.7 kg/year per bear) was excreted in urine, 3% (1.1±0.1 kg/year per bear) was excreted in feces, and bear) was retained in the body. On an area basis, salmon-N redistribution rates were as high as 5.1±0.7 mg/m 2 per year per bear within 500 m of the stream but dropped off greatly with increasing distance. We estimated that 15.5-17.8% of the total N in spruce foliage within 500 m of the stream was derived from salmon. Of that, bears had distributed 83-84%. Thus, brown bears can be an important vector of salmon-derived N into riparian ecosystems, but their effects are highly variable spatially and a function of bear density.

  10. Water use by terrestrial ecosystems: temporal variability in rainforest and agricultural contributions to evapotranspiration in Mato Grosso, Brazil

    International Nuclear Information System (INIS)

    Lathuillière, Michael J; Johnson, Mark S; Donner, Simon D

    2012-01-01

    The state of Mato Grosso, Brazil, has experienced rapid land use changes from the expansion of rain-fed agriculture (primarily soybean and pasture). This study presents changes to evapotranspiration contributions from terrestrial ecosystems in Mato Grosso over the 2000–9 period. Instead of focusing on land use change to infer hydrologic change, in this paper we assess hydrologic changes using remote sensing, meteorological and agricultural production data to determine the rainforest, crop and pasture components of total evapotranspiration. Humid tropical rainforest evapotranspiration represented half of the state’s total evapotranspiration in 2000 despite occupying only 40% of the total land area. Annual evapotranspiration fluxes from rainforest declined at a rate of 16.2 km 3 y −1 (R 2 = 0.82, p-value < 0.01) as a result of deforestation between 2000 and 2009, representing a 25% decline in rainforest evapotranspiration since 2000. By 2009, rainforest cover accounted for only 40% of total evapotranspiration. Over the same period, crop evapotranspiration doubled, but this increase was offset by a decline in pasture evapotranspiration. Pasture fluxes were at least five times larger than crop evapotranspiration fluxes in 2000–9, with increases spatially focused at the agricultural frontier. The results highlight the expanding appropriation of soil moisture stocks for use in Mato Grosso’s rain-fed agroecosystems. (letter)

  11. Oxidation of atmospheric methane in Northern European soils, comparison with other ecosystems, and uncertainties in the global terrestrial sink

    DEFF Research Database (Denmark)

    Smith, K.A.; Dobbie, K.E.; Ball, B.C.

    2000-01-01

    to the oxidation. The effect of temperature was small, attributed to substrate limitation and low atmospheric concentration. Analysis of all available data for CH4 oxidation rates in situ showed similar log-normal distributions to those obtained for our results, with generally little difference between different......This paper reports the range and statistical distribution of oxidation rates of atmospheric CH4 in soils found in Northern Europe in an international study, and compares them with published data for various other ecosystems. It reassesses the size, and the uncertainty in, the global terrestrial CH4...... sink, and examines the effect of land-use change and other factors on the oxidation rate. Only soils with a very high water table were sources of CH4; all others were sinks. Oxidation rates varied from 1 to nearly 200 µg CH4 m-2 h-1; annual rates for sites measured for =1 y were 0.1-9.1 kg CH4 ha-1 y-1...

  12. Net exchanges of CO2, CH4 and N2O between the terrestrial ecosystems and the atmosphere in boreal and arctic region: Towards a full greenhouse gas budget

    Science.gov (United States)

    Zhang, B.; Tian, H.; Lu, C.; Yang, J.; Kamaljit, K.; Pan, S.

    2014-12-01

    Boreal and arctic terrestrial ecosystem is a unique ecological region due to large portion of wetland and permafrost distribution. Increasing disturbances, like permafrost-thaw, fire event, climate extreme, would greatly change the patterns and variations of greenhouse gas emission and further affect the feedback between terrestrial ecosystem and climate change. Carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) accounted for more than 85% of the radioactive forcing (RF) due to long-lived greenhouse gases. However, few studies have considered the full budget of three gases together in this region. In this study, we used a process-based model (Dynamic Land Ecosystem Model), driven by multiple global change factors, to quantify the magnitude, spatial and temporal variation of CO2, CH4 and N2O across the boreal and arctic regions. Simulated results have been evaluated against field observations, inventory-based and atmospheric inversion estimates. By implementing a set of factorial simulations, we further quantify the relative contribution of climate, atmospheric composition, fire to the CO2, CH4 and N2O fluxes. Continued warming climate potentially could shift the inter-annual and intra-annual variation of greenhouse gases fluxes. The understanding of full budget in this region could provide insights for reasonable future projection, which is also crucial for developing effective mitigation strategies.

  13. Uncertainties in carbon residence time and NPP-driven carbon uptake in terrestrial ecosystems of the conterminous USA: a Bayesian approach

    Directory of Open Access Journals (Sweden)

    Xuhui Zhou

    2012-10-01

    Full Text Available Carbon (C residence time is one of the key factors that determine the capacity of ecosystem C storage. However, its uncertainties have not been well quantified, especially at regional scales. Assessing uncertainties of C residence time is thus crucial for an improved understanding of terrestrial C sequestration. In this study, the Bayesian inversion and Markov Chain Monte Carlo (MCMC technique were applied to a regional terrestrial ecosystem (TECO-R model to quantify C residence times and net primary productivity (NPP-driven ecosystem C uptake and assess their uncertainties in the conterminous USA. The uncertainty was represented by coefficient of variation (CV. The 13 spatially distributed data sets of C pools and fluxes have been used to constrain TECO-R model for each biome (totally eight biomes. Our results showed that estimated ecosystem C residence times ranged from 16.6±1.8 (cropland to 85.9±15.3 yr (evergreen needleleaf forest with an average of 56.8±8.8 yr in the conterminous USA. The ecosystem C residence times and their CV were spatially heterogeneous and varied with vegetation types and climate conditions. Large uncertainties appeared in the southern and eastern USA. Driven by NPP changes from 1982 to 1998, terrestrial ecosystems in the conterminous USA would absorb 0.20±0.06 Pg C yr−1. Their spatial pattern was closely related to the greenness map in the summer with larger uptake in central and southeast regions. The lack of data or timescale mismatching between the available data and the estimated parameters lead to uncertainties in the estimated C residence times, which together with initial NPP resulted in the uncertainties in the estimated NPP-driven C uptake. The Bayesian approach with MCMC inversion provides an effective tool to estimate spatially distributed C residence time and assess their uncertainties in the conterminous USA.

  14. Carbon exchange between ecosystems and atmosphere in the Czech Republic is affected by climate factors

    International Nuclear Information System (INIS)

    Marek, Michal V.; Janous, Dalibor; Taufarova, Klara; Havrankova, Katerina; Pavelka, Marian; Kaplan, Veroslav; Markova, Irena

    2011-01-01

    By comparing five ecosystem types in the Czech Republic over several years, we recorded the highest carbon sequestration potential in an evergreen Norway spruce forest (100%) and an agroecosystem (65%), followed by European beech forest (25%) and a wetland ecosystem (20%). Because of a massive ecosystem respiration, the final carbon gain of the grassland was negative. Climate was shown to be an important factor of carbon uptake by ecosystems: by varying the growing season length (a 22-d longer season in 2005 than in 2007 increased carbon sink by 13%) or by the effect of short- term synoptic situations (e.g. summer hot and dry days reduced net carbon storage by 58% relative to hot and wet days). Carbon uptake is strongly affected by the ontogeny and a production strategy which is demonstrated by the comparison of seasonal course of carbon uptake between coniferous (Norway spruce) and deciduous (European beech) stands. - Highlights: → Highest carbon sequestration potential in evergreen Norway spruce forest (100%) and an agroecosystem (65%), followed by European beech forest (25%) and a wetland ecosystem (20%). → The final carbon gain of the grassland was negative (massive ecosystem respiration). → Climate is important factor of net primary productivity. → Carbon uptake is strongly affected by the ontogeny and a production strategy of ecosystem. - Identification of the apparent differences in the carbon storage by different ecosystem types.

  15. Variations and trends of terrestrial NPP and its relation to climate

    Indian Academy of Sciences (India)

    Considering global climate change, near surface temperature is the major factor affecting the terrestrial ecosystem, followed by the precipitation. This means terrestrial ecosystem NPP is more closely related to near surface temperature than precipitation. Between 1976 and 2005, NPP shows an obvious increasing temporal ...

  16. Does microbial biomass affect pelagic ecosystem efficiency? An experimental study.

    Science.gov (United States)

    Wehr, J D; Le, J; Campbell, L

    1994-01-01

    Bacteria and other microorganisms in the pelagic zone participate in the recycling of organic matter and nutrients within the water column. The microbial loop is thought to enhance ecosystem efficiency through rapid recycling and reduced sinking rates, thus reducing the loss of nutrients contained in organisms remaining within the photic zone. We conducted experiments with lake communities in 5400-liter mesocosms, and measured the flux of materials and nutrients out of the water column. A factorial design manipulated 8 nutrient treatments: 4 phosphorus levels × 2 nitrogen levels. Total sedimentation rates were greatest in high-N mesocosms; within N-surplus communities, [Symbol: see text]1 µM P resulted in 50% increase in total particulate losses. P additions without added N had small effects on nutrient losses from the photic zone; +2 µM P tanks received 334 mg P per tank, yet after 14 days lost only 69 mg more particulate-P than did control communities. Nutrient treatments resulted in marked differences in phytoplankton biomass (twofold N effect, fivefold P effect in +N mesocosms only), bacterioplankton densities (twofold N-effect, twofold P effects in -N and +N mesocosms), and the relative importance of autotrophic picoplankton (maximum in high NY mesocosms). Multiple regression analysis found that of 8 plankton and water chemistry variables, the ratio of autotrophic picoplankton to total phytoplankton (measured as chlorophyll α) explained the largest portion of the total variation in sedimentation loss rates (65% of P-flux, 57% of N-flux, 26% of total flux). In each case, systems with greater relative importance of autotrophic picoplankton had significantly reduced loss rates. In contrast, greater numbers of planktonic bacteria were associated with increased sedimentation rates and lower system efficiency. We suggest that different microbial components may have contrasting effects on the presumed enhanced efficiency provided by the microbial loop.

  17. Recording of ecological half-lives of 90Sr and 137Cs in terrestrial and aquatic ecosystems

    International Nuclear Information System (INIS)

    Proehl, G.; Fiedler, I.; Ehlken, S.

    2004-01-01

    Within this project, the long-term behaviour of 90 Sr and 137 Cs in foods, feeds and a variety of environmental was analysed. The long-term behaviour is quantified by means of the ecological half-life which integrates all processes that cause a decrease of activity in a given medium as leaching, fixation and erosion. The following results were achieved: - For plant and animal food products, the ecological half-lives are in the range of 4 to 6 and 10 to 20 years for cesium and strontium respectively. The ecological half-lives for the period 1965 to 1985 are slightly shorter than those derived from monitoring measurements performed after 1987, due to the ongoing deposition in the post weapons' fallout period. - According to the German radioecological model that is applied during licensing of nuclear installations to assess radiation exposures to the general due to planned releases, the ecological half-lives for plant food products are 26 and 13 a for cesium and strontium respectively. In radioecological model that is used within the decision support system RODOS, the ecological half-lives are 8 years for Cesium and 14 years for strontium, which agrees well with the finding of this study. - For roe deer, deer, wild boar and forest plants (including mushrooms), under Middle European conditions, the ecological half-lives are about 12 years for cesium. However, in Ukraine, the cesium levels in forest products are much more persistent; in some cases the decrease of activity is only caused by the radioactive decay. - The variability of the long-term behaviour of 137Cs and 90Sr in freshwater ecosystems is much more pronounced than for terrestrial systems. It depends strongly on the sitespecific characteristics. The observed ecological half-lives for 137Cs and 90Sr cover a wide range from several days to several years. - The data to derive ecological half-lives of cesium in soil is relatively poor. For the upper soil layer of 0-10 cm, ecological half-lives were derived

  18. Use of geochemical and isotope tracers to assess groundwater dependency of a terrestrial ecosystem: case study from southern Poland

    Science.gov (United States)

    Zurek, Anna J.; Witczak, Stanislaw; Kania, Jaroslaw; Rozanski, Kazimierz; Dulinski, Marek; Wachniew, Przemyslaw

    2015-04-01

    The presented study was aimed at better understanding of the functioning of groundwater dependent terrestrial ecosystem (GDTE) located in the south of Poland. The studied GDTE consists of a valuable forest stand (Niepolomice Forest) and associated wetland (Wielkie Bloto fen). It relies not only on shallow, unconfined aquifer but indirectly also on groundwater originating from the deeper confined aquifer, underlying the Quaternary cover and separated from it by an aquitard of variable thickness. The main objective of the study was to evaluate the contribution of groundwater to the water balance of the studied GDTE and thereby assess the potential risk to this system associated with intense exploitation of the deeper aquifer. The Wielkie Błoto fen area and the adjacent parts of Niepolomice Forest are drained by the Dluga Woda stream with 8.2 km2 of gauged catchment area. Hydrometric measurements, carried out on the Dluga Woda stream over two-year period (August 2011 - August 2013) were supplemented by chemical and isotope analyses of stream water, monitored on monthly basis. Physico-chemical parameters of the stream water (SEC, pH, Na content, Na/Cl molar ratio) and isotope tracers (deuterium, oxygen-18 and tritium) were used to quantify the expected contribution of groundwater seepage from the deeper aquifer to the water balance of the Dluga Woda catchment. The mean transit time of water through the catchment, derived from temporal variations of δ18O and tritium content in the Dluga Woda stream, was in the order of three months. This fast component of the total discharge of Dluga Woda stream is associated surface runoff and groundwater flow paths through the Quaternary cover. The slow component devoid of tritium and probably originated from the deeper Neogene aquifer is equal to approximately 30% of the total discharge. The relationships between the physico-chemical parameters of the stream water and the flow rate of Dluga Woda clearly indicate that the monitored

  19. Diagnosing and Assessing Uncertainties of the Carbon Cycle in Terrestrial Ecosystem Models from a Multi-Model Ensemble Experiment

    Science.gov (United States)

    Wang, W.; Dungan, J. L.; Hashimoto, H.; Michaelis, A.; Milesi, C.; Ichii, K.; Nemani, R. R.

    2009-12-01

    We are conducting an ensemble modeling exercise using the Terrestrial Observation and Prediction System (TOPS) to characterize structural uncertainty in carbon fluxes and stocks estimates from different ecosystem models. The experiment uses public-domain versions of Biome-BGC, LPJ, TOPS-BGC, and CASA, driven by a consistent set of climate fields for North America at 8km resolution and daily/monthly time steps over the period of 1982-2006. A set of diagnostics is developed to characterize the behavior of the models in the climate (temperature-precipitation) space, and to evaluate the simulated carbon cycle in an integrated way. The key findings of this study include that: (relative) optimal primary production is generally found in climate regions where the relationship between annual temperature (T, oC) and precipitation (P, mm) is defined by P = 50*T+500; the ratios between NPP and GPP are close to 50% on average, yet can vary between models and in different climate regions; the allocation of carbon to leaf growth represents a positive feedback to the primary production, and different approaches to constrain this process have significant impacts on the simulated carbon cycle; substantial differences in biomass stocks may be induced by small differences in the tissue turnover rate and the plant mortality; the mean residence time of soil carbon pools is strongly influenced by schemes of temperature regulations; non-respiratory disturbances (e.g., fires) are the main driver for NEP, yet its magnitudes vary between models. Overall, these findings indicate that although the structures of the models are similar, the uncertainties among them can be large, highlighting the problem inherent in relying on only one modeling approach to map surface carbon fluxes or to assess vegetation-climate interactions.

  20. Cooling tower drift studies at the Paducah, Kentucky Gaseous Diffusion Plant. [Transport of drift-derived chromium in terrestrial ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, F.G.; Hanna, S.R.; Parr, P.D.

    1979-01-01

    The transfer and fate of chromium from cooling tower drift to terrestrial ecosystems were quantified at the Department of Energy's uranium enrichment facility at Paducah, Kentucky. Chromium concentrations in plant materials (fescue grass) decreased with increasing distance from the cooing tower, ranging from 251 +- 19 ppM at 15 meters to 0.52 +- 0.07 ppM at 1500 meters. The site of drift contamination, size characteristics, and elemental content of drift particles were determined using a scanning electron microscope with energy dispersive x-ray analysis capabilities. Results indicate that elemental content in drift water (mineral residue) may not be equivalent to the content in the recirculating cooling water of the tower. This hypothesis is contrary to basic assumptions in calculating drift emissions. A laboratory study simulating throughfall from 1 to 6 inches of rain suggested that there are more exchange sites associated with litter than live foliage. Leachate from each one inch throughfall simulant removed 3% of the drift mass from litter compared to 7 to 9% from live foliage. Results suggest that differences in retention are related to chemical properties of the drift rather than physical lodging of the particle residue. To determine the potential for movement of drift-derived chromium to surface streams, soil--water samplers (wells) were placed along a distance gradient to Little Bayou Creek. Samples from two depths following rainstorms revealed the absence of vertical or horizontal movement with maximum concentrations of 0.13 ppb at 50 meters from the tower. Preliminary model estimates of drift deposition are compared to depositionmeasurements. Isopleths of the predicted deposition are useful to identify areas of maximum drift transport in the environs of the gaseous diffusion plant.

  1. Monitoring the effects of air pollution on terrestrial ecosystems in Varanger (Norway) and Nikel Pechenga (Russian Federation) using remote sensing

    International Nuclear Information System (INIS)

    Tommervik, H.; Johansen, B.E.; Pedersen, J.P.

    1995-01-01

    During the period 1988-1993, NORUT Information Technology carried out a research project on the effects of air pollution on terrestrial ecosystems in the areas of Varanger (Norway) and Nikel-Pechenga (Russia). To maintain environmental surveillance over the extensive border area, NORUT used satellite remote sensing data in combination with ground measurements. During the project, we produced vegetation cover maps for four different years (1973, 1979, 1985 and 1988), a change detection image, and a vegetation change map. One of the major changes that can be observed on the vegetation cover maps is that the area with licehn-dominated vegetation decreased from 2783 km 2 in 1973 to 538 km 2 in 1988. Comparison of the vegetation cover maps and the change detection map with the total number of emissions of SO 2 from industry shows a strong correlation between the decrease in lichen-dominated vegetation and the dramatic increase in emissions in the period 1973-1988. A correlation between the degradation of the vegetation and the SO 2 concentration in the air has also been documented. The area of severe air pollution impacts increased from approximately 400 km 2 in 1973 to more than 5000 km 2 in 1988. This study shows that the critical loads/levels of air pollution have been exceeded for lichen-dominated vegetation cover types in the eastern parts of the study area. Finally, this study concludes that the use of optical remote sensing (Landsat MSS data) to map vegetation cover changes related to the impacts of air pollution was successful, with an overall classification accuracy of about 80%

  2. Radionuclides in terrestrial ecosystems

    International Nuclear Information System (INIS)

    Allen, S.E.; Horrill, A.D.; Howard, B.J.; Lowe, V.P.W.; Parkinson, J.A.

    1983-07-01

    The subject is discussed under the headings: concentration and spatial distribution of radionuclides in grazed and ungrazed saltmarshes; incorporation of radionuclides by sheep grazing on an estuarine saltmarsh; inland transfer of radionuclides by birds feeding in the estuaries and saltmarshes at Ravenglass; radionuclides in contrasting types of coastal pastures and taken up by individual plant species found in west Cumbria; procedures developed and used for the measurement of alpha and gamma emitters in environmental materials. (U.K.)

  3. Carbon exchange between ecosystems and atmosphere in the Czech Republic is affected by climate factors.

    Science.gov (United States)

    Marek, Michal V; Janouš, Dalibor; Taufarová, Klára; Havránková, Kateřina; Pavelka, Marian; Kaplan, Věroslav; Marková, Irena

    2011-05-01

    By comparing five ecosystem types in the Czech Republic over several years, we recorded the highest carbon sequestration potential in an evergreen Norway spruce forest (100%) and an agroecosystem (65%), followed by European beech forest (25%) and a wetland ecosystem (20%). Because of a massive ecosystem respiration, the final carbon gain of the grassland was negative. Climate was shown to be an important factor of carbon uptake by ecosystems: by varying the growing season length (a 22-d longer season in 2005 than in 2007 increased carbon sink by 13%) or by the effect of short- term synoptic situations (e.g. summer hot and dry days reduced net carbon storage by 58% relative to hot and wet days). Carbon uptake is strongly affected by the ontogeny and a production strategy which is demonstrated by the comparison of seasonal course of carbon uptake between coniferous (Norway spruce) and deciduous (European beech) stands. Copyright © 2011 Elsevier Ltd. All rights reserved.

  4. How disturbances and management practices affect bird communities in a Carpathian river ecosystem?

    Science.gov (United States)

    Lacko, Jozef; Topercer, Ján; Súľovský, Marek

    2018-04-01

    We studied how interactions between disturbances, succession, human alterations and other habitat and landscape attributes affect bird community patterns in a lower reach of a large West Carpathian river Váh with complex disturbance and alteration histories. Breeding-bird communities, their habitats (54 variables) and surrounding landscapes (11 metrics) were sampled using standardized point counts with limited distances at 40 riparian sites divided among two transects along a 12.9 km river stretch. The most frequent and abundant birds were generalists typically associated with forest edge habitats, such as Parus major, Sylvia atricapilla, Fringilla coelebs, Oriolus oriolus, Phylloscopus collybita, Sturnus vulgaris, Turdus merula and Luscinia megarhynchos. Abundances show significant increase at the lower transect responding apparently to greater size and heterogeneity of riparian habitats and more abundant food supply linked to more diverse and intense human influences in a suburban zone. Both indirect (NMDS) and direct ordination (CCA) revealed remarkably large number of evenly important factors underlying riparian bird-habitat interactions. It suggests considerable environmental heterogeneity and complexity of these interactions as a likely outcome of long and complex disturbance and alteration histories of the area. Yet structure and relative importance of first two gradients (longitudinal and lateral linkages) remains simple and stable, complying well with predictions of river continuum concept and stream ecosystem theory. Of the nine statistically significant variables most strongly correlated with first two CCA axes, percentages of Helianthus tuberosus, footpaths, fields, Calystegia sepium and steep banks uphold our hypotheses predicting significant effects of invasive species, visitor disturbances, agricultural land use and unaltered river banks/bed on bird community composition and structure. A small but significant contribution of patch size standard

  5. Effects of contemporary land-use and land-cover change on the carbon balance of terrestrial ecosystems in the United States

    Science.gov (United States)

    Sleeter, Benjamin M.; Liu, Jinxun; Daniel, Colin; Rayfield, Bronwyn; Sherba, Jason; Hawbaker, Todd J.; Zhu, Zhiliang; Selmants, Paul; Loveland, Thomas R.

    2018-01-01

    Changes in land use and land cover (LULC) can have profound effects on terrestrial carbon dynamics, yet their effects on the global carbon budget remain uncertain. While land change impacts on ecosystem carbon dynamics have been the focus of numerous studies, few efforts have been based on observational data incorporating multiple ecosystem types spanning large geographic areas over long time horizons. In this study we use a variety of synoptic-scale remote sensing data to estimate the effect of LULC changes associated with urbanization, agricultural expansion and contraction, forest harvest, and wildfire on the carbon balance of terrestrial ecosystems (forest, grasslands, shrublands, and agriculture) in the conterminous United States (i.e. excluding Alaska and Hawaii) between 1973 and 2010. We estimate large net declines in the area of agriculture and forest, along with relatively small increases in grasslands and shrublands. The largest net change in any class was an estimated gain of 114 865 km2 of developed lands, an average rate of 3282 km2 yr−1. On average, US ecosystems sequestered carbon at an annual rate of 254 Tg C yr−1. In forest lands, the net sink declined by 35% over the study period, largely a result of land-use legacy, increasing disturbances, and reductions in forest area due to land use conversion. Uncertainty in LULC change data contributed to a ~16% margin of error in the annual carbon sink estimate prior to 1985 (approximately ±40 Tg C yr−1). Improvements in LULC and disturbance mapping starting in the mid-1980s reduced this uncertainty by ~50% after 1985. We conclude that changes in LULC are a critical component to understanding ecosystem carbon dynamics, and continued improvements in detection, quantification, and attribution of change have the potential to significantly reduce current uncertainties.

  6. Effects of contemporary land-use and land-cover change on the carbon balance of terrestrial ecosystems in the United States

    Science.gov (United States)

    Sleeter, Benjamin M.; Liu, Jinxun; Daniel, Colin; Rayfield, Bronwyn; Sherba, Jason; Hawbaker, Todd J.; Zhu, Zhiliang; Selmants, Paul C.; Loveland, Thomas R.

    2018-04-01

    Changes in land use and land cover (LULC) can have profound effects on terrestrial carbon dynamics, yet their effects on the global carbon budget remain uncertain. While land change impacts on ecosystem carbon dynamics have been the focus of numerous studies, few efforts have been based on observational data incorporating multiple ecosystem types spanning large geographic areas over long time horizons. In this study we use a variety of synoptic-scale remote sensing data to estimate the effect of LULC changes associated with urbanization, agricultural expansion and contraction, forest harvest, and wildfire on the carbon balance of terrestrial ecosystems (forest, grasslands, shrublands, and agriculture) in the conterminous United States (i.e. excluding Alaska and Hawaii) between 1973 and 2010. We estimate large net declines in the area of agriculture and forest, along with relatively small increases in grasslands and shrublands. The largest net change in any class was an estimated gain of 114 865 km2 of developed lands, an average rate of 3282 km2 yr‑1. On average, US ecosystems sequestered carbon at an annual rate of 254 Tg C yr‑1. In forest lands, the net sink declined by 35% over the study period, largely a result of land-use legacy, increasing disturbances, and reductions in forest area due to land use conversion. Uncertainty in LULC change data contributed to a ~16% margin of error in the annual carbon sink estimate prior to 1985 (approximately ±40 Tg C yr‑1). Improvements in LULC and disturbance mapping starting in the mid-1980s reduced this uncertainty by ~50% after 1985. We conclude that changes in LULC are a critical component to understanding ecosystem carbon dynamics, and continued improvements in detection, quantification, and attribution of change have the potential to significantly reduce current uncertainties.

  7. Nitrogen and Carbon Cycling in a Grassland Community Ecosystem as Affected by Elevated Atmospheric CO2

    Directory of Open Access Journals (Sweden)

    H. A. Torbert

    2012-01-01

    Full Text Available Increasing global atmospheric carbon dioxide (CO2 concentration has led to concerns regarding its potential effects on terrestrial ecosystems and the long-term storage of carbon (C and nitrogen (N in soil. This study examined responses to elevated CO2 in a grass ecosystem invaded with a leguminous shrub Acacia farnesiana (L. Willd (Huisache. Seedlings of Acacia along with grass species were grown for 13 months at CO2 concentrations of 385 (ambient, 690, and 980 μmol mol−1. Elevated CO2 increased both C and N inputs from plant growth which would result in higher soil C from litter fall, root turnover, and excretions. Results from the incubation indicated an initial (20 days decrease in N mineralization which resulted in no change in C mineralization. However, after 40 and 60 days, an increase in both C and N mineralization was observed. These increases would indicate that increases in soil C storage may not occur in grass ecosystems that are invaded with Acacia over the long term.

  8. Effects of enhanced ultraviolet-B radiation on terrestrial subarctic ecosystems and implications for interactions with increased atmospheric CO2

    International Nuclear Information System (INIS)

    Gehrke, C.; Johanson, U.; Bjoern, L.O.; Gwynn-Jones, D.; Callaghan, T.V.; Lee, J.A.

    1996-01-01

    Two predominating types of ecosystems in the Subarctic were exposed to simulated environmental perturbations. A heathland ecosystem was exposed to enhanced UV-B (corresponding to 15% ozone depletion) combined with either increased CO 2 (600 ppm) or additional watering. An ombrotrophic peatland ecosystem was exposed to only enhanced UV-B. Responses both at a plant species level, including different growth forms and life strategies, and at a trophic level (decomposition of organic matter) were studied. There were differences both in the magnitude and direction of plant responses to enhanced UV-B. The four dwarf shrub species in the heathland developed shorter stems, though not at a significant level in the two deciduous species. The leaves of the evergreen, thick-leaved V. vitus-idaea grew thicker under enhanced UV-B, while leaves of the two deciduous species V. myrtillus and V. uliginosum grew thinner. The heathland moss H. splendens showed reduced growth after two and three years under enhanced UV-B but when water was applied simultaneously growth was stimulated by enhanced UV-B. The peat moss S. fuscum had 20% less height increment during the first growing season under enhanced UV-B. Mosses tended to respond quicker to a change in UV-B regime than long-lived dwarf shrubs did. They responded in growth and phenological development already after a few weeks of treatment. Enhanced UV-B in the heathland affected decomposition of organic matter. It had direct negative effects on decomposer community function and structure and indirect negative effects on turnover of V. uliginosum leaf litter by changing the tissue quality of the litter. This was confirmed by studies in the field with another deciduous dwarf shrub (V. myrtillus). Increased growth due to enhanced CO 2 was recorded in V. myrtillus during the first growing season. No change in growth was apparent in any of the dwarf shrubs on a longer-term perspective but the number of flowers and berries were increased in

  9. Ecological risk assessment for the terrestrial ecosystem under chronic radioactive pollution - Ecological risk assessment for the biota on regional radioactive waste storage

    Energy Technology Data Exchange (ETDEWEB)

    Lavrentyeva, G.V.; Synzynys, B.I.; Shoshina, R.R.; Mirzeabasov, O.A. [Obninsk Institute for Nuclear Power Engineering, branch of the National Research Nuclear University MEPhI, Department of Ecology, Studgorodok,1, 249040 Obninsk, Kaluga region (Russian Federation)

    2014-07-01

    Now the methods of ecological regulation of a radiation factor from risk assessment are developed poorly. The paper attempts to assess and forecast the terrestrial ecosystem conditions under chronic ionizing radiation by calculating the critical loads. The paper is aimed at developing a methodology to assess the ecological risk for a terrestrial ecosystem under chronic radioactive pollution in a biotope of a regional radioactive waste storage. Objects and Methods: Biotope monitoring of a radioactive waste storage makes clear that the radioecological situation in this territory is stipulated by technogenic {sup 90}Sr found in soil, ground water and biota. Terrestrial mollusks of a shrubby Snail type (Bradybaena fruticum) were chosen as reference species due to their activity to accumulate {sup 90}Sr in shells and the number of colony-forming soil units (CFU) as reference indices. The number of CFU was determined by inoculation of solid medium. Soil and mollusk samples have been collected at most representative sites identified in the previous studies. To assess {sup 90}Sr content in the samples collected, radiochemical separation was used with further radionuclide activity measurements by a 'BETA-01C' scintillation beta-ray spectrometer according to a standard procedure of {sup 90}Sr content assessment from beta-radiation of its daughter radionuclide {sup 90}Y. Ecological risk was calculated from analyzed critical loads using a 'dose-effect' dependence. Statistical data processing was realized with Excell 2007 and R software programs [R Development Core Team, 2010]. The software R was also used for GIS creation. Results and Discussion: A methodology of ecological risk assessment for the terrestrial ecosystem under chronic radioactive pollution of a biotope near a regional radioactive waste storage has been developed in terms of the critical environmental loads analyzed. It consists of five stages: determination of effect indicators and assessment

  10. Small but powerful: top predator local extinction affects ecosystem structure and function in an intermittent stream.

    Science.gov (United States)

    Rodríguez-Lozano, Pablo; Verkaik, Iraima; Rieradevall, Maria; Prat, Narcís

    2015-01-01

    Top predator loss is a major global problem, with a current trend in biodiversity loss towards high trophic levels that modifies most ecosystems worldwide. Most research in this area is focused on large-bodied predators, despite the high extinction risk of small-bodied freshwater fish that often act as apex consumers. Consequently, it remains unknown if intermittent streams are affected by the consequences of top-predators' extirpations. The aim of our research was to determine how this global problem affects intermittent streams and, in particular, if the loss of a small-bodied top predator (1) leads to a 'mesopredator release', affects primary consumers and changes whole community structures, and (2) triggers a cascade effect modifying the ecosystem function. To address these questions, we studied the top-down effects of a small endangered fish species, Barbus meridionalis (the Mediterranean barbel), conducting an enclosure/exclosure mesocosm experiment in an intermittent stream where B. meridionalis became locally extinct following a wildfire. We found that top predator absence led to 'mesopredator release', and also to 'prey release' despite intraguild predation, which contrasts with traditional food web theory. In addition, B. meridionalis extirpation changed whole macroinvertebrate community composition and increased total macroinvertebrate density. Regarding ecosystem function, periphyton primary production decreased in apex consumer absence. In this study, the apex consumer was functionally irreplaceable; its local extinction led to the loss of an important functional role that resulted in major changes to the ecosystem's structure and function. This study evidences that intermittent streams can be affected by the consequences of apex consumers' extinctions, and that the loss of small-bodied top predators can lead to large ecosystem changes. We recommend the reintroduction of small-bodied apex consumers to systems where they have been extirpated, to restore

  11. Small but powerful: top predator local extinction affects ecosystem structure and function in an intermittent stream.

    Directory of Open Access Journals (Sweden)

    Pablo Rodríguez-Lozano

    Full Text Available Top predator loss is a major global problem, with a current trend in biodiversity loss towards high trophic levels that modifies most ecosystems worldwide. Most research in this area is focused on large-bodied predators, despite the high extinction risk of small-bodied freshwater fish that often act as apex consumers. Consequently, it remains unknown if intermittent streams are affected by the consequences of top-predators' extirpations. The aim of our research was to determine how this global problem affects intermittent streams and, in particular, if the loss of a small-bodied top predator (1 leads to a 'mesopredator release', affects primary consumers and changes whole community structures, and (2 triggers a cascade effect modifying the ecosystem function. To address these questions, we studied the top-down effects of a small endangered fish species, Barbus meridionalis (the Mediterranean barbel, conducting an enclosure/exclosure mesocosm experiment in an intermittent stream where B. meridionalis became locally extinct following a wildfire. We found that top predator absence led to 'mesopredator release', and also to 'prey release' despite intraguild predation, which contrasts with traditional food web theory. In addition, B. meridionalis extirpation changed whole macroinvertebrate community composition and increased total macroinvertebrate density. Regarding ecosystem function, periphyton primary production decreased in apex consumer absence. In this study, the apex consumer was functionally irreplaceable; its local extinction led to the loss of an important functional role that resulted in major changes to the ecosystem's structure and function. This study evidences that intermittent streams can be affected by the consequences of apex consumers' extinctions, and that the loss of small-bodied top predators can lead to large ecosystem changes. We recommend the reintroduction of small-bodied apex consumers to systems where they have been

  12. Spider-mediated flux of PCBs from contaminated sediments to terrestrial ecosystems and potential risks to arachnivorous birds

    Science.gov (United States)

    We investigated aquatic insect utilization and PCB exposure in riparian spiders at the Lake Hartwell superfund site (Clemson, SC , USA). We sampled sediments, adult chironomids, terrestrial insects, riparian spiders (Tetragnathidae, Araneidae, and Mecynogea lemniscata), and upla...

  13. Application of Terrestrial Ecosystem Monitoring under the CAFF Circumpolar Biodiversity Monitoring Program: Designing and Implementing Terrestrial Monitoring to Establish the Canadian High Arctic Research Station as a Flagship Arctic Environmental Monitoring Site

    Science.gov (United States)

    McLennan, D.; Kehler, D.

    2016-12-01

    The Canadian High Arctic Research Station (CHARS) is scheduled for completion in July 2017 and is the northern science component of Polar Knowledge Canada (POLAR). A mandated goal for POLAR is to establish the adjacent Experimental and Reference Area (ERA) as an Arctic Flagship monitoring site that will track change in Arctic terrestrial, freshwater and marine ecosystems. Situated in the community of Cambridge Bay, CHARS provides the opportunity to draw on the Indigenous Knowledge of local residents to help design and conduct the monitoring, and to operate 12 months a year. Monitoring at CHARS will be linked to networks nationally and internationally, and is being designed so that change in key indicators can be understood in terms of drivers and processes, modeled and scaled up regionally, and used to predict important changes in critical indicators. As a partner in the Circumpolar Biodiversity Monitoring Program (CBMP), the monitoring design for terrestrial ecosystems follows approaches outlined by the CBMP Terrestrial Expert Monitoring Group, who have listed key monitoring questions and identified a list of important Focal Ecosystem Components (FECs). To link drivers to FECs we are proposing a multi-scaled approach: 1) an Intensive Monitoring Area to establish replicated monitoring plots that track change in snow depth and condition, active layer depth, soil temperature, soil moisture, and soil solution chemistry that are spatially and temporally linked to changes in microbiological activity, CO2/CH4 net ecosystem flux, vegetation relative frequency, species composition, growth and foliar nutrient concentration, arthropod abundance, lemming abundance and health, and shorebird/songbird abundance and productivity. 2) These intensive observations are supported by watershed scale measures that will monitor, during the growing season, lemming winter nest abundance, songbird, shorebird and waterfowl staging and nesting, and other observations; in the winter we will

  14. Current and future carbon budget at Takayama site, Japan, evaluated by a regional climate model and a process-based terrestrial ecosystem model.

    Science.gov (United States)

    Kuribayashi, Masatoshi; Noh, Nam-Jin; Saitoh, Taku M; Ito, Akihiko; Wakazuki, Yasutaka; Muraoka, Hiroyuki

    2017-06-01

    Accurate projection of carbon budget in forest ecosystems under future climate and atmospheric carbon dioxide (CO 2 ) concentration is important to evaluate the function of terrestrial ecosystems, which serve as a major sink of atmospheric CO 2 . In this study, we examined the effects of spatial resolution of meteorological data on the accuracies of ecosystem model simulation for canopy phenology and carbon budget such as gross primary production (GPP), ecosystem respiration (ER), and net ecosystem production (NEP) of a deciduous forest in Japan. Then, we simulated the future (around 2085) changes in canopy phenology and carbon budget of the forest by incorporating high-resolution meteorological data downscaled by a regional climate model. The ecosystem model overestimated GPP and ER when we inputted low-resolution data, which have warming biases over mountainous landscape. But, it reproduced canopy phenology and carbon budget well, when we inputted high-resolution data. Under the future climate, earlier leaf expansion and delayed leaf fall by about 10 days compared with the present state was simulated, and also, GPP, ER and NEP were estimated to increase by 25.2%, 23.7% and 35.4%, respectively. Sensitivity analysis showed that the increase of NEP in June and October would be mainly caused by rising temperature, whereas that in July and August would be largely attributable to CO 2 fertilization. This study suggests that the downscaling of future climate data enable us to project more reliable carbon budget of forest ecosystem in mountainous landscape than the low-resolution simulation due to the better predictions of leaf expansion and shedding.

  15. Effect of trophic level on the radiocesium frequency distribution in aquatic and terrestrial ecosystems at Chornobyl and nuclear sites in the United States

    International Nuclear Information System (INIS)

    Smith, Michael H.; Tsyusko-Omeltchenko, Olga; Oleksyk, Taras K.

    2003-01-01

    There are significant linear relationship between the standard deviation and the mean of radiocesium concentration for samples of soils, sediments, plants, and animals from Chornobyl and nuclear sites in the United States. The universal occurrence of this relationship in all types of samples suggests that a non-normal frequency distribution should be expected. The slopes of these relationships are similar for fish and mammals from the two regions of the world but those for plants are not. The slopes for plants are similar for aquatic and terrestrial ecosystems within each region. We hypothesize that there are relationships between the four moments of the frequency distribution of radiocesium (mean, variance, skewness, and kurtosis), and that these relationships are caused by the functional properties of the organisms and other characteristics of the ecosystem. The way in which radiocesium was distributed across the landscape does not seem to be a factor in determining the form of the frequency distribution. (author)

  16. Terrestrial ecology

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    The main effort of the Terrestrial Ecology Division has been redirected to a comprehensive study of the Espiritu Santo Drainage Basin located in northeastern Puerto Rico. The general objective are to provide baseline ecological data for future environmental assessment studies at the local and regional levels, and to provide through an ecosystem approach data for the development of management alternatives for the wise utilization of energy, water, and land resources. The interrelationships among climate, vegetation, soils, and man, and their combined influence upon the hydrologic cycle will be described and evaluated. Environmental management involves planning and decision making, and both require an adequate data base. At present, little is known about the interworkings of a complete, integrated system such as a drainage basin. A literature survey of the main research areas confirmed that, although many individual ecologically oriented studies have been carried out in a tropical environment, few if any provide the data base required for environmental management. In view of rapidly changing socio-economic conditions and natural resources limitations, management urgently requires data from these systems: physical (climatological), biological, and cultural. This integrated drainage basin study has been designed to provide such data. The scope of this program covers the hydrologic cycle as it is affected by the interactions of the physical, biological, and cultural systems

  17. Wild food in Europe: a synthesis of knowledge and data of terrestrial wild food as an ecosystem service

    NARCIS (Netherlands)

    Schulp, C.J.E.; Thuiller, W.; Verburg, P.H.

    2014-01-01

    Wild food is an iconic ecosystem service that receives little attention in quantifying, valuating and mapping studies, due to the perceived low importance or due to lack of data. Here, we synthesize available data on the importance of wild food as ecosystem service, its spatial distribution and

  18. Uptake of Cadmium, Copper, Lead, and Zinc from Sediments by an Aquatic Macrophyte and by Terrestrial Arthropods in a Freshwater Wetland Ecosystem.

    Science.gov (United States)

    Kim, Heung-Tae; Kim, Jae Geun

    2016-08-01

    The objective of this study was to investigate trace-metal [cadmium (Cd), copper (Cu), lead (Pb), zinc (Zn)] biotransference and biomagnification in terrestrial biota at different trophic levels (primary producer-top predator) of a wetland ecosystem. We investigated whether metal concentrations in the sediment are reflected in terrestrial arthropods and aquatic plants. We sampled the floating-leaved plant Trapa japonica; its species-specific primary consumer, the leaf beetle Galerucella nipponensis; and two predatory arthropods (the water strider Gerris sp. and the wolf spider Arctosa sp.) from three wetlands with different sedimentary metal concentrations. The δ(13)C and δ(15)N signatures in the trophic link between the plants and the leaf beetles supported the specificity of their feeding relationship. The stable isotope signatures indicate that the leaf beetle could be an important link in the trophic transfer of the metals. Transference factors (TFs) were 1 for all biota, and the concentrations were positively correlated with the trophic levels. Thus, there may be Cu and Zn biomagnification in the arthropods. We noted TF 1 among the arthropods. Therefore, Cd is probably not biomagnified between T. japonica and G. nipponensis, but it might be biomagnified in the arthropods. The metal burden in terrestrial arthropods may also be influenced by uptake from the sediment by aquatic plants.

  19. Quantification of terrestrial ecosystem carbon dynamics in the conterminous United States combining a process-based biogeochemical model and MODIS and AmeriFlux data

    Directory of Open Access Journals (Sweden)

    M. Chen

    2011-09-01

    Full Text Available Satellite remote sensing provides continuous temporal and spatial information of terrestrial ecosystems. Using these remote sensing data and eddy flux measurements and biogeochemical models, such as the Terrestrial Ecosystem Model (TEM, should provide a more adequate quantification of carbon dynamics of terrestrial ecosystems. Here we use Moderate Resolution Imaging Spectroradiometer (MODIS Enhanced Vegetation Index (EVI, Land Surface Water Index (LSWI and carbon flux data of AmeriFlux to conduct such a study. We first modify the gross primary production (GPP modeling in TEM by incorporating EVI and LSWI to account for the effects of the changes of canopy photosynthetic capacity, phenology and water stress. Second, we parameterize and verify the new version of TEM with eddy flux data. We then apply the model to the conterminous United States over the period 2000–2005 at a 0.05° × 0.05° spatial resolution. We find that the new version of TEM made improvement over the previous version and generally captured the expected temporal and spatial patterns of regional carbon dynamics. We estimate that regional GPP is between 7.02 and 7.78 Pg C yr−1 and net primary production (NPP ranges from 3.81 to 4.38 Pg C yr−1 and net ecosystem production (NEP varies within 0.08–0.73 Pg C yr−1 over the period 2000–2005 for the conterminous United States. The uncertainty due to parameterization is 0.34, 0.65 and 0.18 Pg C yr−1 for the regional estimates of GPP, NPP and NEP, respectively. The effects of extreme climate and disturbances such as severe drought in 2002 and destructive Hurricane Katrina in 2005 were captured by the model. Our study provides a new independent and more adequate measure of carbon fluxes for the conterminous United States, which will benefit studies of carbon-climate feedback and facilitate policy-making of carbon management and climate.

  20. The Phanerozoic diversification of silica-cycling testate amoebae and its possible links to changes in terrestrial ecosystems

    Science.gov (United States)

    Bosak, Tanja; Lara, Enrique; Mitchell, Edward A.D.

    2015-01-01

    The terrestrial cycling of Si is thought to have a large influence on the terrestrial and marine primary production, as well as the coupled biogeochemical cycles of Si and C. Biomineralization of silica is widespread among terrestrial eukaryotes such as plants, soil diatoms, freshwater sponges, silicifying flagellates and testate amoebae. Two major groups of testate (shelled) amoebae, arcellinids and euglyphids, produce their own silica particles to construct shells. The two are unrelated phylogenetically and acquired biomineralizing capabilities independently. Hyalosphenids, a group within arcellinids, are predators of euglyphids. We demonstrate that hyalosphenids can construct shells using silica scales mineralized by the euglyphids. Parsimony analyses of the current hyalosphenid phylogeny indicate that the ability to “steal” euglyphid scales is most likely ancestral in hyalosphenids, implying that euglyphids should be older than hyalosphenids. However, exactly when euglyphids arose is uncertain. Current fossil record contains unambiguous euglyphid fossils that are as old as 50 million years, but older fossils are scarce and difficult to interpret. Poor taxon sampling of euglyphids has also prevented the development of molecular clocks. Here, we present a novel molecular clock reconstruction for arcellinids and consider the uncertainties due to various previously used calibration points. The new molecular clock puts the origin of hyalosphenids in the early Carboniferous (∼370 mya). Notably, this estimate coincides with the widespread colonization of land by Si-accumulating plants, suggesting possible links between the evolution of Arcellinid testate amoebae and the expansion of terrestrial habitats rich in organic matter and bioavailable Si. PMID:26734499

  1. Does litter size variation affect models of terrestrial carnivore extinction risk and management?

    Directory of Open Access Journals (Sweden)

    Eleanor S Devenish-Nelson

    Full Text Available Individual variation in both survival and reproduction has the potential to influence extinction risk. Especially for rare or threatened species, reliable population models should adequately incorporate demographic uncertainty. Here, we focus on an important form of demographic stochasticity: variation in litter sizes. We use terrestrial carnivores as an example taxon, as they are frequently threatened or of economic importance. Since data on intraspecific litter size variation are often sparse, it is unclear what probability distribution should be used to describe the pattern of litter size variation for multiparous carnivores.We used litter size data on 32 terrestrial carnivore species to test the fit of 12 probability distributions. The influence of these distributions on quasi-extinction probabilities and the probability of successful disease control was then examined for three canid species - the island fox Urocyon littoralis, the red fox Vulpes vulpes, and the African wild dog Lycaon pictus. Best fitting probability distributions differed among the carnivores examined. However, the discretised normal distribution provided the best fit for the majority of species, because variation among litter-sizes was often small. Importantly, however, the outcomes of demographic models were generally robust to the distribution used.These results provide reassurance for those using demographic modelling for the management of less studied carnivores in which litter size variation is estimated using data from species with similar reproductive attributes.

  2. The rise of fire: Fossil charcoal in late Devonian marine shales as an indicator of expanding terrestrial ecosystems, fire, and atmospheric change

    Science.gov (United States)

    Rimmer, Susan M.; Hawkins, Sarah J.; Scott, Andrew C.; Cressler, Walter L.

    2015-01-01

    Fossil charcoal provides direct evidence for fire events that, in turn, have implications for the evolution of both terrestrial ecosystems and the atmosphere. Most of the ancient charcoal record is known from terrestrial or nearshore environments and indicates the earliest occurrences of fire in the Late Silurian. However, despite the rise in available fuel through the Devonian as vascular land plants became larger and trees and forests evolved, charcoal occurrences are very sparse until the Early Mississippian where extensive charcoal suggests well-established fire systems. We present data from the latest Devonian and Early Mississippian of North America from terrestrial and marine rocks indicating that fire became more widespread and significant at this time. This increase may be a function of rising O2 levels and the occurrence of fire itself may have contributed to this rise through positive feedback. Recent atmospheric modeling suggests an O2 low during the Middle Devonian (around 17.5%), with O2 rising steadily through the Late Devonian and Early Mississippian (to 21–22%) that allowed for widespread burning for the first time. In Devonian-Mississippian marine black shales, fossil charcoal (inertinite) steadily increases up-section suggesting the rise of widespread fire systems. There is a concomitant increase in the amount of vitrinite (preserved woody and other plant tissues) that also suggests increased sources of terrestrial organic matter. Even as end Devonian glaciation was experienced, fossil charcoal continued to be a source of organic matter being introduced into the Devonian oceans. Scanning electron and reflectance microscopy of charcoal from Late Devonian terrestrial sites indicate that the fires were moderately hot (typically 500–600 °C) and burnt mainly surface vegetation dominated by herbaceous zygopterid ferns and lycopsids, rather than being produced by forest crown fires. The occurrence and relative abundance of fossil charcoal in

  3. Evaluating the effects of future climate change and elevated CO2 on the water use efficiency in terrestrial ecosystems of China

    Science.gov (United States)

    Zhu, Q.; Jiang, H.; Peng, C.; Liu, J.; Wei, X.; Fang, X.; Liu, S.; Zhou, G.; Yu, S.

    2011-01-01

    Water use efficiency (WUE) is an important variable used in climate change and hydrological studies in relation to how it links ecosystem carbon cycles and hydrological cycles together. However, obtaining reliable WUE results based on site-level flux data remains a great challenge when scaling up to larger regional zones. Biophysical, process-based ecosystem models are powerful tools to study WUE at large spatial and temporal scales. The Integrated BIosphere Simulator (IBIS) was used to evaluate the effects of climate change and elevated CO2 concentrations on ecosystem-level WUE (defined as the ratio of gross primary production (GPP) to evapotranspiration (ET)) in relation to terrestrial ecosystems in China for 2009–2099. Climate scenario data (IPCC SRES A2 and SRES B1) generated from the Third Generation Coupled Global Climate Model (CGCM3) was used in the simulations. Seven simulations were implemented according to the assemblage of different elevated CO2 concentrations scenarios and different climate change scenarios. Analysis suggests that (1) further elevated CO2concentrations will significantly enhance the WUE over China by the end of the twenty-first century, especially in forest areas; (2) effects of climate change on WUE will vary for different geographical regions in China with negative effects occurring primarily in southern regions and positive effects occurring primarily in high latitude and altitude regions (Tibetan Plateau); (3) WUE will maintain the current levels for 2009–2099 under the constant climate scenario (i.e. using mean climate condition of 1951–2006 and CO2concentrations of the 2008 level); and (4) WUE will decrease with the increase of water resource restriction (expressed as evaporation ratio) among different ecosystems.

  4. Critical levels and loads of atmospheric pollutants for terrestrial and aquatic ecosystems. The emergence of a scientific concept. Application potentials and their limits

    International Nuclear Information System (INIS)

    Landmann, G.

    1993-01-01

    The 'critical loads and levels' are defined as the highest atmospheric deposition rate or concentration of a gaseous pollutant, respectively, that will not cause harmful effects on sensitive elements of an ecosystem. The recent emergence of the concept of critical loads and levels is described, from the first explicit mention in 1986 to the production of the first European maps in 1991. The difficulties linked to the definition of the concept and to its english-derived terminology are discussed. The main approaches used for assessing critical loads and levels are briefly described. Important research is developed under the auspices of the Convention of Geneva (Long Range Transboundary Air Pollution Transport, UN-ECE), arising from intensive studies which have been carried out on the effects of air pollution on terrestrial and aquatic ecosystems for the past ten or fifteen years. Current knowledge is summarized, as well as the remaining gaps (and questions) which hinder the calculation of the critical thresholds. Finally, beyond the fundamental relevance of this scientifically sound and easily understood concept, its limits are pointed out. In brief, the 'critical loads and levels' concept is attractive and motivating to many scientists: it implies to apply an integrated and finalized approach, favors the prospecting of poorly known ecosystems and regions, and represents an interesting interface with decision makers

  5. Abundance, biomass production, nutrient content, and the possible role of terrestrial salamanders in Missouri Ozark forest ecosystems

    Science.gov (United States)

    R.D. Semlitsch; K.M. O' Donnell; F.R. Thompson

    2014-01-01

    The transfer of energy and nutrients largely depends on the role of animals in the movement of biomass between trophic levels and ecosystems. Despite the historical recognition that amphibians could play an important role in the movement of biomass and nutrients, very few studies have provided reliable estimates of abundance and density of amphibians to reveal their...

  6. Asymmetric warming significantly affects net primary production, but not ecosystem carbon balances of forest and grassland ecosystems in northern China.

    Science.gov (United States)

    Su, Hongxin; Feng, Jinchao; Axmacher, Jan C; Sang, Weiguo

    2015-03-13

    We combine the process-based ecosystem model (Biome-BGC) with climate change-scenarios based on both RegCM3 model outputs and historic observed trends to quantify differential effects of symmetric and asymmetric warming on ecosystem net primary productivity (NPP), heterotrophic respiration (Rh) and net ecosystem productivity (NEP) of six ecosystem types representing different climatic zones of northern China. Analysis of covariance shows that NPP is significant greater at most ecosystems under the various environmental change scenarios once temperature asymmetries are taken into consideration. However, these differences do not lead to significant differences in NEP, which indicates that asymmetry in climate change does not result in significant alterations of the overall carbon balance in the dominating forest or grassland ecosystems. Overall, NPP, Rh and NEP are regulated by highly interrelated effects of increases in temperature and atmospheric CO2 concentrations and precipitation changes, while the magnitude of these effects strongly varies across the six sites. Further studies underpinned by suitable experiments are nonetheless required to further improve the performance of ecosystem models and confirm the validity of these model predictions. This is crucial for a sound understanding of the mechanisms controlling the variability in asymmetric warming effects on ecosystem structure and functioning.

  7. Asymmetric warming significantly affects net primary production, but not ecosystem carbon balances of forest and grassland ecosystems in northern China

    Science.gov (United States)

    Su, Hongxin; Feng, Jinchao; Axmacher, Jan C.; Sang, Weiguo

    2015-03-01

    We combine the process-based ecosystem model (Biome-BGC) with climate change-scenarios based on both RegCM3 model outputs and historic observed trends to quantify differential effects of symmetric and asymmetric warming on ecosystem net primary productivity (NPP), heterotrophic respiration (Rh) and net ecosystem productivity (NEP) of six ecosystem types representing different climatic zones of northern China. Analysis of covariance shows that NPP is significant greater at most ecosystems under the various environmental change scenarios once temperature asymmetries are taken into consideration. However, these differences do not lead to significant differences in NEP, which indicates that asymmetry in climate change does not result in significant alterations of the overall carbon balance in the dominating forest or grassland ecosystems. Overall, NPP, Rh and NEP are regulated by highly interrelated effects of increases in temperature and atmospheric CO2 concentrations and precipitation changes, while the magnitude of these effects strongly varies across the six sites. Further studies underpinned by suitable experiments are nonetheless required to further improve the performance of ecosystem models and confirm the validity of these model predictions. This is crucial for a sound understanding of the mechanisms controlling the variability in asymmetric warming effects on ecosystem structure and functioning.

  8. Vertical structure and pH as factors for chitinolytic and pectinolytic microbial community of soils and terrestrial ecosystems of different climatic zones

    Science.gov (United States)

    Lukacheva, Evgeniya; Natalia, Manucharova

    2016-04-01

    Chitin is a naturally occurring fibre-forming polymer that plays a protective role in many lower animals similar to that of cellulose in plants. Also it's a compound of cell walls of fungi. Chemically it is a long-chain unbranched polysaccharide made of N-acetylglucosamine residues; it is the second most abundant organic compound in nature, after cellulose. Pectin is a structural heteropolysaccharide contained in the primary cell walls of terrestrial plants. Roots of the plants and root crops contain pectin. Chitin and pectin are widely distributed throughout the natural world. Structural and functional features of the complex microbial degradation of biopolymers one of the most important direction in microbial ecology. But there is no a lot of data concerns degradation in vertical structure of terrestrial ecosystems and detailed studies concerning certain abiotic features as pH. Microbial complexes of natural areas were analyzed only as humus horizons (A1) of the soil profile. Only small part of microbial community could be studied with this approach. It is known that ecosystems have their own structure. It is possible to allocate some vertical tiers: phylloplane, litter (soil covering), soil. We investigated chitinolytic and pectinolytic microbial communities dedicated to different layers of the ecosystems. Also it was described depending on pH dominated in certain ecosystem with certain conditions. Quantity of eukaryote and procaryote organisms increased in the test samples with chitin and pectin. Increasing of eukaryote in samples with pectin was more then in samples with chitin. Also should be noted the significant increasing of actinomycet's quantity in the samples with chitin in comparison with samples with pectin. The variety and abundance of bacteria in the litter samples increased an order of magnitude as compared to other probes. Further prokaryote community was investigated by method FISH (fluorescence in situ hybridization). FISH is a cytogenetic

  9. Radioecology of natural systems in Colordao. Fourteenth annual progress report, May 1, 1975--July 31, 1976. [Pu diffusion in terrestrial ecosystems at Rocky Flats Plant

    Energy Technology Data Exchange (ETDEWEB)

    Whicker, F.W.

    1976-08-01

    This report summarizes project activities during the period May 1, 1975 through July 31, 1976. The major study on the distribution and levels of Pu in major components of the terrestrial ecosystem at Rocky Flats was completed. Supportive studies on the ecology and pathology of small mammals and their role in Pu transport were essentially completed as well. Detailed studies on mule deer food habits, population dynamics, and movements at Rocky Flats are progressing. These studies are designed to measure the potential of mule deer in transporting Pu to uncontrolled areas. Alpha autoradiographic studies designed to measure Pu particle size and distribution and spatial patterns in soil were initiated. Field and greenhouse transport pathways from soil to vegetation are in progress and some early results reported. The status of studies on seasonal kinetics of Cs in a montane lake and stable lead geochemistry in an alpine lake watershed are also reported.

  10. EcoDoses improving radiological assessment of doses to man from terrestrial ecosystems. A status report for the NKS-B project 2003

    Energy Technology Data Exchange (ETDEWEB)

    Bergan, T. [Lavrans Skuterud, Haevard Thoerring (Norway); Liland, A. [Norwegian Radiation Protection Authority (NRPA) (Denmark)] (eds.)

    2004-05-01

    The NKS B-programme EcoDoses project started in 2003 as a collaboration between all the Nordic countries. The aim of the project is to improve the radiological assessments of doses to man from terrestrial ecosystems. The first part, conducted in 2003, has focussed on an extensive collation and review of both published and unpublished data from all the Nordic countries for the nuclear weapons fallout period and the post-Chemobyl period. This included data on radionuclides in air filters, precipitation, soil samples, milk and reindeer. Based on this, an improved model for estimating radioactive fallout based on precipitation data during the nuclear weapons fallout period has been developed. Effective ecological half- lives for 137Cs and 90Sr in milk have been calculated for the nuclear weapons fallout period. For reindeer the ecological half- lives for 137Cs have been calculated for both the nuclear weapons fallout period and the post-Chemobyl period. The data were also used to compare modelling results with observed concentrations. This was done at a workshop where the radioecological food-and-dose module in the ARGOS decision support system was used to predict transfer of deposited radionuclides to foodstuffs and subsequent radiation doses to man. The work conducted the first year is presented in this report and gives interesting, new results relevant for terrestrial radioecology. (au)

  11. Nutrients, Toxins, and Water in Terrestrial and Aquatic Ecosystems Treated with Sewage Plant Effluents. Final Report of the Upland Recharge Program

    Energy Technology Data Exchange (ETDEWEB)

    Woodwell, G. M.; Ballard, J. T.; Clinton, J.; Pecan, E. V.

    1976-01-01

    The objective of this work was to appraise the capacity of terrestrial and aquatic plant communities for absorbing and retaining nutrients and organic matter in sewage and for releasing ''clean'' water. Experimental systems included a sere representative of the Eastern Deciduous Forest, a timothy field, two Phalaris arundinacea meadows, a freshwater marsh, a pond, and a marsh-pond complex. Sewage of two qualities was applied at the rate of 5 cm per week; one treatment was equivalent to the release from a primary treatment sewage plant, the second to that from a secondary treatment plant. Under normal circumstances, without the addition of water or nutrients in sewage, the flux of nutrients into the groundwater was greatest under the agricultural communities and least under the late successional forest communities. All the terrestrial communities were net sources of most elements. Because the agricultural communities were fertilized and a substantial fraction of the fertilizer applied remained after the first year, the agricultural communities appeared to be net sinks during the first year of the experiment. The highest concentrations of nutrients in the percolate of the untreated communities commonly occurred in the earliest stages of succession. This relationship was especially conspicuous for nitrogen. Phosphorus and iron appeared to be held tightly within most ecosystems.

  12. Increased light-use efficiency in northern terrestrial ecosystems indicated by CO 2 and greening observations: INCREASE IN NH LIGHT USE EFFICIENCY

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Rebecca T. [Science and Solutions for a Changing Planet DTP, Imperial College London, London UK; AXA Chair Programme in Biosphere and Climate Impacts, Department of Life Sciences, Imperial College London, London UK; Department of Physics, Imperial College London, London UK; Prentice, Iain Colin [AXA Chair Programme in Biosphere and Climate Impacts, Department of Life Sciences, Imperial College London, London UK; Grantham Institute: Climate Change and the Environment, Imperial College London, London UK; Graven, Heather [Department of Physics, Imperial College London, London UK; Grantham Institute: Climate Change and the Environment, Imperial College London, London UK; Ciais, Philippe [Laboratoire des Sciences du Climat et de l' Environnement, Saint-Aubin France; Fisher, Joshua B. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena California USA; Hayes, Daniel J. [School of Forest Resources, University of Maine, Orono Maine USA; Huang, Maoyi [Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA; Huntzinger, Deborah N. [School of Earth Sciences and Environmental Sustainability, Northern Arizona University, Flagstaff Arizona USA; Ito, Akihiko [Center for Global Environmental Research, National Institute for Environmental Studies, Tsukuba Japan; Jain, Atul [Department of Atmospheric Sciences, University of Illinois at Urbana-Champaign, Urbana Illinois USA; Mao, Jiafu [Climate Change Science Institute and Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge Tennessee USA; Michalak, Anna M. [Department of Global Ecology, Carnegie Institution for Science, Stanford California USA; Peng, Shushi [Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing China; Poulter, Benjamin [Department of Ecology, Montana State University, Bozeman Montana USA; Ricciuto, Daniel M. [Climate Change Science Institute and Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge Tennessee USA; Shi, Xiaoying [Climate Change Science Institute and Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge Tennessee USA; Schwalm, Christopher [Woods Hole Research Center, Falmouth Massachusetts USA; Tian, Hanqin [International Center for Climate and Global Change Research, School of Forestry and Wildlife Sciences, Auburn University, Auburn Alabama USA; Zeng, Ning [Department of Atmospheric and Oceanic Science and Earth System Science Interdisciplinary Center, University of Maryland, College Park Maryland USA

    2016-11-04

    Observations show an increasing amplitude in the seasonal cycle of CO2 (ASC) north of 45°N of 56 ± 9.8% over the last 50 years and an increase in vegetation greenness of 7.5–15% in high northern latitudes since the 1980s. However, the causes of these changes remain uncertain. Historical simulations from terrestrial biosphere models in the Multiscale Synthesis and Terrestrial Model Intercomparison Project are compared to the ASC and greenness observations, using the TM3 atmospheric transport model to translate surface fluxes into CO2 concentrations. We find that the modeled change in ASC is too small but the mean greening trend is generally captured. Modeled increases in greenness are primarily driven by warming, whereas ASC changes are primarily driven by increasing CO2. We suggest that increases in ecosystem-scale light use efficiency (LUE) have contributed to the observed ASC increase but are underestimated by current models. We highlight potential mechanisms that could increase modeled LUE.

  13. Mapping of critical loads of acidity for the Italian terrestrial ecosystems; Mappa dei carichi critici di acidita' totale riferita al territorio italiano

    Energy Technology Data Exchange (ETDEWEB)

    Bonanni, P.; Brini, S.; Delmonaco, G.; Liburdi, C.; Trocciola, A.; Vetrella, G. [ENEA, Centro Ricerche Casaccia, Rome (Italy). Dipt. Ambiente

    1999-07-01

    In this report the mapping of critical loads of acidity for the Italian terrestrial ecosystems is presented. The level 0 method (Stockholm Environment Institute) has been used to determine sensitivity to acid deposition; this semi-quantitative method has been modified to address some Italian characteristics. The sensitivity of the Italian soils to acidification is not particularly elevated: there are really only few small areas with poor tolerance to acid depositions in the north-east Italy, Alpine and Prealpine region. [Italian] Nel presente relazione vengono riportati i risultati della mappatura riferita ad ecosistemi terrestri del territorio italiano, dei carichi critici per l'acidita' totale. Il calcolo dei carichi e' stato eseguito sulla base della metodologia messa a punto dallo Stockholm Environment Institute con alcune modifiche per adattarlo meglio alle caratteristiche del territorio italiano. Si dimostra che la sensibilita' dei suoli italiani all'acidificazione non sia particolarmente elevata: sono state riscontrate infatti solo alcune aree, peraltro con superficie limitata, con una scarsa tolleranza alle deposizioni acide nelle zone del Nord Est, in zona alpina e prealpina.

  14. Isotopic and anatomical evidence of an herbivorous diet in the Early Tertiary giant bird Gastornis. Implications for the structure of Paleocene terrestrial ecosystems

    Science.gov (United States)

    Angst, D.; Lécuyer, C.; Amiot, R.; Buffetaut, E.; Fourel, F.; Martineau, F.; Legendre, S.; Abourachid, A.; Herrel, A.

    2014-04-01

    The mode of life of the early Tertiary giant bird Gastornis has long been a matter of controversy. Although it has often been reconstructed as an apex predator feeding on small mammals, according to other interpretations, it was in fact a large herbivore. To determine the diet of this bird, we analyze here the carbon isotope composition of the bone apatite from Gastornis and contemporaneous herbivorous mammals. Based on 13C-enrichment measured between carbonate and diet of carnivorous and herbivorous modern birds, the carbonate δ13C values of Gastornis bone remains, recovered from four Paleocene and Eocene French localities, indicate that this bird fed on plants. This is confirmed by a morphofunctional study showing that the reconstructed jaw musculature of Gastornis was similar to that of living herbivorous birds and unlike that of carnivorous forms. The herbivorous Gastornis was the largest terrestrial tetrapod in the Paleocene biota of Europe, unlike the situation in North America and Asia, where Gastornis is first recorded in the early Eocene, and the largest Paleocene animals were herbivorous mammals. The structure of the Paleocene terrestrial ecosystems of Europe may have been similar to that of some large islands, notably Madagascar, prior to the arrival of humans.

  15. Nitrogen, organic carbon and sulphur cycling in terrestrial ecosystems: linking nitrogen saturation to carbon limitation of soil microbial processes

    Czech Academy of Sciences Publication Activity Database

    Kopáček, Jiří; Cosby, B. J.; Evans, C. D.; Hruška, J.; Moldan, F.; Oulehle, F.; Šantrůčková, H.; Tahovská, K.; Wright, R. F.

    2013-01-01

    Roč. 115, 1-3 (2013), s. 33-51 ISSN 0168-2563. [BIOGEOMON : international symposium on ecosystem behavior /7./. Northport, 15.07.2012-20.07.2012] R&D Projects: GA ČR(CZ) GAP504/12/1218 Institutional support: RVO:60077344 Keywords : nitrogen * carbon * sulphur * acidification * forest soil * modelling Subject RIV: DJ - Water Pollution ; Quality Impact factor: 3.730, year: 2013

  16. Coupling the Canadian Terrestrial Ecosystem Model (CTEM v. 2.0 to Environment and Climate Change Canada's greenhouse gas forecast model (v.107-glb

    Directory of Open Access Journals (Sweden)

    B. Badawy

    2018-02-01

    Full Text Available The Canadian Land Surface Scheme and the Canadian Terrestrial Ecosystem Model (CLASS-CTEM together form the land surface component in the family of Canadian Earth system models (CanESMs. Here, CLASS-CTEM is coupled to Environment and Climate Change Canada (ECCC's weather and greenhouse gas forecast model (GEM-MACH-GHG to consistently model atmosphere–land exchange of CO2. The coupling between the land and the atmospheric transport model ensures consistency between meteorological forcing of CO2 fluxes and CO2 transport. The procedure used to spin up carbon pools for CLASS-CTEM for multi-decadal simulations needed to be significantly altered to deal with the limited availability of consistent meteorological information from a constantly changing operational environment in the GEM-MACH-GHG model. Despite the limitations in the spin-up procedure, the simulated fluxes obtained by driving the CLASS-CTEM model with meteorological forcing from GEM-MACH-GHG were comparable to those obtained from CLASS-CTEM when it is driven with standard meteorological forcing from the Climate Research Unit (CRU combined with reanalysis fields from the National Centers for Environmental Prediction (NCEP to form CRU-NCEP dataset. This is due to the similarity of the two meteorological datasets in terms of temperature and radiation. However, notable discrepancies in the seasonal variation and spatial patterns of precipitation estimates, especially in the tropics, were reflected in the estimated carbon fluxes, as they significantly affected the magnitude of the vegetation productivity and, to a lesser extent, the seasonal variations in carbon fluxes. Nevertheless, the simulated fluxes based on the meteorological forcing from the GEM-MACH-GHG model are consistent to some extent with other estimates from bottom-up or top-down approaches. Indeed, when simulated fluxes obtained by driving the CLASS-CTEM model with meteorological data from the GEM-MACH-GHG model are used as

  17. Coupling the Canadian Terrestrial Ecosystem Model (CTEM v. 2.0) to Environment and Climate Change Canada's greenhouse gas forecast model (v.107-glb)

    Science.gov (United States)

    Badawy, Bakr; Polavarapu, Saroja; Jones, Dylan B. A.; Deng, Feng; Neish, Michael; Melton, Joe R.; Nassar, Ray; Arora, Vivek K.

    2018-02-01

    The Canadian Land Surface Scheme and the Canadian Terrestrial Ecosystem Model (CLASS-CTEM) together form the land surface component in the family of Canadian Earth system models (CanESMs). Here, CLASS-CTEM is coupled to Environment and Climate Change Canada (ECCC)'s weather and greenhouse gas forecast model (GEM-MACH-GHG) to consistently model atmosphere-land exchange of CO2. The coupling between the land and the atmospheric transport model ensures consistency between meteorological forcing of CO2 fluxes and CO2 transport. The procedure used to spin up carbon pools for CLASS-CTEM for multi-decadal simulations needed to be significantly altered to deal with the limited availability of consistent meteorological information from a constantly changing operational environment in the GEM-MACH-GHG model. Despite the limitations in the spin-up procedure, the simulated fluxes obtained by driving the CLASS-CTEM model with meteorological forcing from GEM-MACH-GHG were comparable to those obtained from CLASS-CTEM when it is driven with standard meteorological forcing from the Climate Research Unit (CRU) combined with reanalysis fields from the National Centers for Environmental Prediction (NCEP) to form CRU-NCEP dataset. This is due to the similarity of the two meteorological datasets in terms of temperature and radiation. However, notable discrepancies in the seasonal variation and spatial patterns of precipitation estimates, especially in the tropics, were reflected in the estimated carbon fluxes, as they significantly affected the magnitude of the vegetation productivity and, to a lesser extent, the seasonal variations in carbon fluxes. Nevertheless, the simulated fluxes based on the meteorological forcing from the GEM-MACH-GHG model are consistent to some extent with other estimates from bottom-up or top-down approaches. Indeed, when simulated fluxes obtained by driving the CLASS-CTEM model with meteorological data from the GEM-MACH-GHG model are used as prior estimates

  18. Large herbivores affect forest ecosystem functions by altering the structure of dung beetle communities

    Science.gov (United States)

    Iida, Taichi; Soga, Masashi; Koike, Shinsuke

    2018-04-01

    Dramatic increases in populations of large mammalian herbivores have become a major ecological issue, particularly in the northern hemisphere, due to their substantial impacts on both animal and plant communities through processes such as grazing, browsing, and trampling. However, little is known about the consequences of these population explosions on ecosystem functions. Here, we experimentally investigated how the population density of sika deer (Cervus nippon) in temperate deciduous forest areas in Japan affected the decomposition of mammal dung by dung beetles, which is a key process in forest ecosystems. We measured a range of environmental variables (e.g., vegetation cover, soil hardness) and the dung decomposition rate, measured as the amount of deer dung decomposed during one week, and sampled dung beetles at 16 study sites with three different deer densities (high/intermediate/low). We then used structural equation modeling to investigate the relationships between deer density, environmental variables, the biomass of dung beetles (classified into small or large species), and the dung decomposition rate. We found that the biomass of small species increased with increasing deer density, whereas that of large species was not related to deer density. Furthermore, the dung decomposition rate was positively related to the biomass of small species but unrelated to that of large species. Overall, our results showed that an increase in deer density affects the decomposition rate of mammal dung by changing the structure of dung beetle communities (i.e., increasing the number of small dung beetles). Such an understanding of how increases in large herbivore populations affect ecosystem functions is important for accurately evaluating the ecological consequences of their overabundance and ultimately managing their populations appropriately.

  19. Resilience of Mediterranean terrestrial ecosystems and fire severity in semiarid areas: Responses of Aleppo pine forests in the short, mid and long term.

    Science.gov (United States)

    González-De Vega, S; De Las Heras, J; Moya, D

    2016-12-15

    In recent decades, the fire regime of the Mediterranean Basin has been disturbed by various factors: climate change; forest management policies; land cover; changed landscape. Size and severity have notably increased, which in turn have increased large fires events with >500ha burned (high severity). In spite of Mediterranean ecosystems' high resilience to fire, these changes have implied more vulnerability and reduced natural recovery with irreparable long-term negative effects. Knowledge of the response of ecosystems to increasing severity, mainly in semiarid areas, is still lacking, which is needed to rehabilitate and restore burned areas. Our approach assessed the resilience concept by focusing on the recovery of ecosystem functions and services, measured as changes in the composition and diversity of plant community vegetation and structure. This will be validated in the long term as a model of ecosystem response. Also, depending on the pre-fire characteristics of vegetation, fire severity and the post-fire management, this approach will lead to tools that can be applied to implement post-fire restoration efforts in order to help decision making in planning activities. Regarding Mediterranean ecosystems' ability to recover after wildfires, this study concludes that pre-fire communities are resilient in these fire-prone areas, but the window for natural recovery in semiarid areas of Aleppo pine forest in SE Iberian Peninsula varied from 3 to 15 post-fire years. Fire severity was also key for effects on the ecosystem: the vegetation types of areas burned with low and medium severity recovered naturally, while those areas with a high-severity burn induced shrublands. We concluded that very strong regeneration activity exists in the short term, and that the negative effects of medium- and high-severity fire are evidenced in the mid and long term, which affect natural recovery. Adaptive forest management to rehabilitate and restore burned Mediterranean ecosystems

  20. Development of a data driven process-based model for remote sensing of terrestrial ecosystem productivity, evapotranspiration, and above-ground biomass

    Science.gov (United States)

    El Masri, Bassil

    2011-12-01

    Modeling terrestrial ecosystem functions and structure has been a subject of increasing interest because of the importance of the terrestrial carbon cycle in global carbon budget and climate change. In this study, satellite data were used to estimate gross primary production (GPP), evapotranspiration (ET) for two deciduous forests: Morgan Monroe State forest (MMSF) in Indiana and Harvard forest in Massachusetts. Also, above-ground biomass (AGB) was estimated for the MMSF and the Howland forest (mixed forest) in Maine. Surface reflectance and temperature, vegetation indices, soil moisture, tree height and canopy area derived from the Moderate Resolution Imagining Spectroradiometer (MODIS), the Advanced Microwave Scanning Radiometer (AMRS-E), LIDAR, and aerial imagery respectively, were used for this purpose. These variables along with others derived from remotely sensed data were used as inputs variables to process-based models which estimated GPP and ET and to a regression model which estimated AGB. The process-based models were BIOME-BGC and the Penman-Monteith equation. Measured values for the carbon and water fluxes obtained from the Eddy covariance flux tower were compared to the modeled GPP and ET. The data driven methods produced good estimation of GPP and ET with an average root mean square error (RMSE) of 0.17 molC/m2 and 0.40 mm/day, respectively for the MMSF and the Harvard forest. In addition, allometric data for the MMSF were used to develop the regression model relating AGB with stem volume. The performance of the AGB regression model was compared to site measurements using remotely sensed data for the MMSF and the Howland forest where the model AGB RMSE ranged between 2.92--3.30 Kg C/m2. Sensitivity analysis revealed that improvement in maintenance respiration estimation and remotely sensed maximum photosynthetic activity as well as accurate estimate of canopy resistance will result in improved GPP and ET predictions. Moreover, AGB estimates were

  1. Analysis of chemical factors affecting marine ecosystem around nuclear power plant

    International Nuclear Information System (INIS)

    Chun, Kwan Sik; Choi, Yoon Dong; Chun, Ki Jeong; Kim, Jin Kyu; Jung, Kyeong Chai; Lee, Yeong Keun; Park, Hyo Kook

    1994-06-01

    The ecological data of the coastal area of Youngkwang nuclear power plant from 1987 to 1993 were comprehensively analyzed, and various physical and chemical properties of sea water and sediments were measured. Major factors affecting phytoplankton standing crops were suspended substances, nitrate, and silicate. The contents of iron, chromium, copper, and sulfur in sediments sampled from the discharge channel were slightly higher than those in the other areas. In order to qantify the chemical impacts on marine ecosystem, it is desirable that a systematic survey be made through the whole year cycle to assure the consistency and confidence of the related data. (Author)

  2. Neonicotinoid insecticides negatively affect performance measures of non‐target terrestrial arthropods: a meta‐analysis

    Science.gov (United States)

    Main, Anson; Webb, Elisabeth B.; Goyne, Keith W.; Mengel, Doreen C.

    2018-01-01

    Neonicotinoid insecticides are currently the fastest‐growing and most widely used insecticide class worldwide. Valued for their versatility in application, these insecticides may cause deleterious effects in a range of non‐target (beneficial) arthropods. However, it remains unclear whether strong patterns exist in terms of their major effects, if broad measures of arthropod performance are negatively affected, or whether different functional groups are equally vulnerable. Here, we present a meta‐analysis of 372 observations from 44 field and laboratory studies that describe neonicotinoid effects on 14 arthropod orders across five broad performance measures: abundance, behavior, condition, reproductive success, and survival. Across studies, neonicotinoids negatively affected all performance metrics evaluated; however, magnitude of the effects varied. Arthropod behavior and survival were the most negatively affected and abundance was the least negatively affected. Effects on arthropod functional groups were inconsistent. Pollinator condition, reproductive success, and survival were significantly lower in neonicotinoid treatments compared to untreated controls; whereas, neonicotinoid effects on detritivores were not significant. Although magnitude of arthropod response to neonicotinoids varied among performance measures and functional groups, we documented a consistent negative relationship between exposure to neonicotinoid insecticides in published studies and beneficial arthropod performance.

  3. Ecosystem carbon storage does not vary with increasing mean annual temperature in Hawaiian tropical montane wet forests

    Science.gov (United States)

    Paul Selmants; Creighton Litton; Christian P. Giardina; Greg P. Asner

    2014-01-01

    Theory and experiment agree that climate warming will increase carbon fluxes between terrestrial ecosystems and the atmosphere. The effect of this increased exchange on terrestrial carbon storage is less predictable, with important implications for potential feedbacks to the climate system. We quantified how increased mean annual temperature (MAT) affects ecosystem...

  4. Source-pathway-receptor investigation of the fate of trace elements derived from shotgun pellets discharged in terrestrial ecosystems managed for game shooting

    International Nuclear Information System (INIS)

    Sneddon, Jennifer; Clemente, Rafael; Riby, Philip; Lepp, Nicholas W.

    2009-01-01

    Spent shotgun pellets may contaminate terrestrial ecosystems. We examined the fate of elements originating from shotgun pellets in pasture and woodland ecosystems. Two source-receptor pathways: i) soil-soil pore water-plant and ii) whole earthworm/worm gut contents - washed and unwashed small mammal hair were investigated. Concentrations of Pb and associated contaminants were higher in soils from shot areas than controls. Arsenic and lead concentrations were positively correlated in soils, soil pore water and associated biota. Element concentrations in biota were below statutory levels in all locations. Bioavailability of lead to small mammals, based on concentrations in washed body hair was low. Lead movement from soil water to higher trophic levels was minor compared to lead adsorbed onto body surfaces. Lead was concentrated in earthworm gut and some plants. Results indicate that managed game shooting presents minimal risk in terms of element transfer to soils and their associated biota. - Source-receptor pathway analysis of a managed game shooting site showed no environmental risk of trace element transfer.

  5. Using the Terrestrial Observation and Prediction System (TOPS) to Analyze Impacts of Climate Change on Ecosystems within Northern California Climate Regions

    Science.gov (United States)

    Pitts, K.; Little, M.; Loewenstein, M.; Iraci, L. T.; Milesi, C.; Schmidt, C.; Skiles, J. W.

    2011-12-01

    The projected impacts of climate change on Northern California ecosystems using model outputs from the Terrestrial Observation and Prediction System (TOPS) for the period 1950-2099 based on 1km downscaled climate data from the Geophysical Fluid Dynamics Laboratory (GFDL) model are analyzed in this study. The impacts are analyzed for the Special Report Emissions Scenarios (SRES) A1B and A2, both maintaining present levels of urbanization constant and under projected urban expansion. The analysis is in support of the Climate Adaptation Science Investigation at NASA Ames Research Center. A statistical analysis is completed for time series of temperature, precipitation, gross primary productivity (GPP), evapotranspiration, soil runoff, and vapor pressure deficit. Trends produced from this analysis show that increases in maximum and minimum temperatures lead to declines in peak GPP, length of growing seasons, and overall declines in runoff within the watershed. For Northern California, GPP is projected under the A2 scenario to decrease by 18-25% by the 2090 decade as compared to the 2000 decade. These trends indicate a higher risk to crop production and other ecosystem services, as conditions would be less hospitable to vegetation growth. The increase in dried out vegetation would then lead to a higher risk of wildfire and mudslides in the mountainous regions.

  6. Source-pathway-receptor investigation of the fate of trace elements derived from shotgun pellets discharged in terrestrial ecosystems managed for game shooting

    Energy Technology Data Exchange (ETDEWEB)

    Sneddon, Jennifer [School of Natural Sciences and Psychology, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF (United Kingdom); Clemente, Rafael, E-mail: rclemente@cebas.csic.e [School of Natural Sciences and Psychology, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF (United Kingdom); Riby, Philip [School of Pharmacy and Chemistry, Liverpool John Moores University, Liverpool L3 3AF (United Kingdom); Lepp, Nicholas W., E-mail: n.w.lepp@ljmu.ac.u [School of Natural Sciences and Psychology, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF (United Kingdom)

    2009-10-15

    Spent shotgun pellets may contaminate terrestrial ecosystems. We examined the fate of elements originating from shotgun pellets in pasture and woodland ecosystems. Two source-receptor pathways: i) soil-soil pore water-plant and ii) whole earthworm/worm gut contents - washed and unwashed small mammal hair were investigated. Concentrations of Pb and associated contaminants were higher in soils from shot areas than controls. Arsenic and lead concentrations were positively correlated in soils, soil pore water and associated biota. Element concentrations in biota were below statutory levels in all locations. Bioavailability of lead to small mammals, based on concentrations in washed body hair was low. Lead movement from soil water to higher trophic levels was minor compared to lead adsorbed onto body surfaces. Lead was concentrated in earthworm gut and some plants. Results indicate that managed game shooting presents minimal risk in terms of element transfer to soils and their associated biota. - Source-receptor pathway analysis of a managed game shooting site showed no environmental risk of trace element transfer.

  7. The relative roles of climate and land use in the degradation of a terrestrial ecosystem: a case study from Kjarardalur, West Iceland

    Science.gov (United States)

    Erlendsson, Egill; Gísladóttir, Guðrún

    2016-04-01

    Around AD 870 the virgin environment of Iceland became populated by humans and mammal land herbivores. Since then, the island has lost nearly all of its native birch woodland, resulting in dramatic degradation of landscapes and ecosystems, attributed mainly to over-exploitation of woodlands and late-medieval climate deterioration. As part of policy making in agriculture, a heated debate is ongoing over limitations to sheep grazing in pastures suffering from long-term degradation. In this context the history of climate and land use is of great importance. Those who consider grazing a minimal attribute to land degradation argue that the harsh climate conditions of the little ice age are the primary mechanism behind the current degraded landscape. Others err on the side of caution and propose a careful approach to grazing. This study forms a contribution to the historical context of the impact of grazing upon the Icelandic terrestrial ecosystem. Using the analyses of pollen and spores from coprophilous fungi as principal methods, we present data about historical environmental change from within two different land holdings in Kjarardalur Valley, West Iceland. One dataset comes from within a landholding governed by the chieftain farm Reykholt, the other comes from within the land of the indipendent farm, Norðtunga. In the past the valley was used primarily as a pasture, associated with shielings (organised seasonal grazing). Pollen data from the pasture in Kjarardalur Valley, West Iceland, demonstrate a rapid loss of birch (Betula pubescens) woodland from grazing areas owned by the major farm and institution, Reykholt. The suppressive nature of grazing is demonstrated by the expansion of woodland as soon when animal stocks are reduced, probably as a consequence of the bubonic plague after AD 1402. Resumed exploitation of resources eventually depleted all birch woodland from the Reykholt landholding and precipitated soil erosion. The trajectory of environmental change

  8. Description, calibration and sensitivity analysis of the local ecosystem submodel of a global model of carbon and nitrogen cycling and the water balance in the terrestrial biosphere

    Energy Technology Data Exchange (ETDEWEB)

    Kercher, J.R. [Lawrence Livermore National Lab., CA (United States); Chambers, J.Q. [Lawrence Livermore National Lab., CA (United States)]|[California Univ., Santa Barbara, CA (United States). Dept. of Biological Sciences

    1995-10-01

    We have developed a geographically-distributed ecosystem model for the carbon, nitrogen, and water dynamics of the terrestrial biosphere TERRA. The local ecosystem model of TERRA consists of coupled, modified versions of TEM and DAYTRANS. The ecosystem model in each grid cell calculates water fluxes of evaporation, transpiration, and runoff; carbon fluxes of gross primary productivity, litterfall, and plant and soil respiration; and nitrogen fluxes of vegetation uptake, litterfall, mineralization, immobilization, and system loss. The state variables are soil water content; carbon in live vegetation; carbon in soil; nitrogen in live vegetation; organic nitrogen in soil and fitter; available inorganic nitrogen aggregating nitrites, nitrates, and ammonia; and a variable for allocation. Carbon and nitrogen dynamics are calibrated to specific sites in 17 vegetation types. Eight parameters are determined during calibration for each of the 17 vegetation types. At calibration, the annual average values of carbon in vegetation C, show site differences that derive from the vegetation-type specific parameters and intersite variation in climate and soils. From calibration, we recover the average C{sub v} of forests, woodlands, savannas, grasslands, shrublands, and tundra that were used to develop the model initially. The timing of the phases of the annual variation is driven by temperature and light in the high latitude and moist temperate zones. The dry temperate zones are driven by temperature, precipitation, and light. In the tropics, precipitation is the key variable in annual variation. The seasonal responses are even more clearly demonstrated in net primary production and show the same controlling factors.

  9. Final Report on "Rising CO2 and Long-term Carbon Storage in Terrestrial Ecosystems: An Empirical Carbon Budget Validation"

    Energy Technology Data Exchange (ETDEWEB)

    J. Patrick Megonigal; Bert G. Drake

    2010-08-27

    The primary goal of this report is to report the results of Grant DE-FG02-97ER62458, which began in 1997 as Grant DOE-98-59-MP-4 funded through the TECO program. However, this project has a longer history because DOE also funded this study from its inception in 1985 through 1997. The original grant was focused on plant responses to elevated CO2 in an intact ecosystem, while the latter grant was focused on belowground responses. Here we summarize the major findings across the 25 years this study has operated, and note that the experiment will continue to run through 2020 with NSF support. The major conclusions of the study to date are: (1 Elevated CO2 stimulated plant productivity in the C3 plant community by ~30% during the 25 year study. The magnitude of the increase in productivity varied interannually and was sometime absent altogether. There is some evidence of down-regulation at the ecosystem level across the 25 year record that may be due to interactions with other factors such as sea-level rise or long-term changes in N supply; (2) Elevated CO2 stimulated C4 productivity by <10%, perhaps due to more efficient water use, but C3 plants at elevated CO2 did not displace C4 plants as predicted; (3) Increased primary production caused a general stimulation of microbial processes, but there were both increases and decreases in activity depending on the specific organisms considered. An increase in methanogenesis and methane emissions implies elevated CO2 may amplify radiative forcing in the case of wetland ecosystems; (4) Elevated CO2 stimulated soil carbon sequestration in the form of an increase in elevation. The increase in elevation is 50-100% of the increase in net ecosystem production caused by elevated CO2 (still under analysis). The increase in soil elevation suggests the elevated CO2 may have a positive outcome for the ability of coastal wetlands to persist despite accelerated sea level rise; (5) Crossing elevated CO2 with elevated N causes the elevated CO

  10. Ecology of anuran populations inhabiting thermally stressed aquatic ecosystems, with emphasis on larval Rana pipiens and Bufo terrestris

    International Nuclear Information System (INIS)

    Nelson, D.H.

    1974-01-01

    Field and laboratory studies were conducted to determine the responses of anuran populations to thermally stressed aquatic ecosystems. Adult and larval amphibians were sampled in and around a cool arm of a 67 ha reservoir that receives high temperature effluent from a nuclear production reactor on the Savannah River Plant (SRP) in South Carolina. Patterns for some species were compared with data from nearby unheated areas and analyzed in terms of the thermal gradient (16-45 C) extending the length of the reservoir's cool arm. The adaptation to breeding during nocturnal rainfall fortuitously confers a double advantage especially to anurans breeding in thermally stressed waters. (U.S.)

  11. Impacts of fire on nitrogen cycling in aquatic and terrestrial ecosystems in the Yukon-Kuskokwim River Delta, AK

    Science.gov (United States)

    Schade, J. D.; Jardine, L. E.; Bristol, E. M.; Navarro-Perez, E.; Melton, S.; Jimmie, J. A.; Natali, S.; Mann, P. J.; Holmes, R. M.

    2017-12-01

    Global climate change is having a disproportionate impact on northern high latitudes, including rapid increases in temperature, changes in precipitation, and increasing fire frequency and severity. Wildfires have been shown to strongly influence ecosystem processes through acceleration of permafrost thaw and increased nitrogen (N) availability, the effects of which may increase gaseous loss of carbon (C) to the atmosphere, increase primary production by alleviating N limitation, or both. The extent of these fire impacts has not been well-documented in the Arctic, particularly in areas of discontinuous permafrost. In 2015, the Yukon-Kuskokwim River Delta (YK Delta) in southwestern Alaska experienced the largest fire season in recorded history, providing an opportunity to study wildfire impacts on an area particularly vulnerable to permafrost thaw. Our objectives were to study the impacts of these fires on nitrogen availability in a range of land cover classes, including peat plateaus, channel fens, and aquatic ecosystems distributed across the landscapes. We sampled soils from several vegetation patches on burned and unburned peat plateaus, and soil and surface waters from fens, small ponds, and streams downslope of these sites. All water samples were filtered through GFF filters in the field. Soils were transported frozen to the Woods Hole Research Center and extracted in KCl. All water samples and extracts were analyzed for NH4 and NO3 concentrations. We found substantially higher concentrations of extractable NH4 in burned soils, but very little extractable NO3 in either burned or unburned soils. Water samples also showed higher NH4 in aquatic ecosystems in burned watersheds, but, in contrast to soils, showed relatively high NO3 concentrations, particularly in waters from lower landscape positions. Overall, aquatic ecosystems exhibited higher NO3: NH4 ratios than soil extractions, and increasing NO3: NH4 downslope. These results suggest significant export of

  12. Future stratospheric ozone depletion will affect a subarctic dwarf shrub ecosystem

    Energy Technology Data Exchange (ETDEWEB)

    Johanson, Ulf

    1997-02-01

    The stratospheric ozone depletion and the concomitant increase in ultraviolet-B (UV-B, 280-320 nm) radiation is of global concern due to the effects of UV-B on living organisms. To investigate the effects of increased levels of UV-B, a field irradiation system was established at a subarctic dwarf shrub heath in Northern Sweden (68 deg N). An ozone depletion of 15% under clear sky conditions was simulated over a naturally growing ecosystem. The response of both individual components and processes was studied to reveal changes in ecosystem structure and function. Species with different life strategies (evergreen or deciduous) responded differently both in magnitude and direction. The evergreen species were more responsive to UV-B regarding shoot growth, which could be due to cumulative effects in long-lived tissues, since the retardation in relative growth increased over time of exposure. Leaves of evergreen species became thicker under enhanced UV-B, while leaves of deciduous species became thinner. Decomposition studies (laboratory and in situ) showed that indirect effects of UV-B, due to changes in leaf tissue chemistry affected microbial activity and slowed down the decomposition rate. More directly, UV-B decreased the abundance of some fungal species and hence the composition of species. However, no altered decomposition rate was found when decomposition progressed under high UV-B even if the microorganisms were fewer. This could be due to the increased direct photo degradation of litter that compensates for lower microbial activity. The decomposition rate is therefore strongly dependent on the interception of UV-B at the litter layer. This research has shown that ecosystem components and processes are affected in a number of ways and that there are indications of changes in species composition in a long-term perspective due to differences in responsiveness between the different species. 128 refs, 7 figs

  13. Effects of increasing UV-B radiation and atmospheric CO2 on photosynthesis and growth: implications for terrestrial ecosystems

    International Nuclear Information System (INIS)

    Sullivan, J.H.

    1997-01-01

    Increases in UV-B radiation reaching the earth as a result of stratospheric ozone depletion will most likely accompany increases in atmospheric CO 2 concentrations. Many studies have examined the effects of each factor independently, but few have evaluated the combined effects of both UV-B radiation and elevated CO 2 . In general the results of such studies have shown independent effects on growth or seed yield. Although interspecific variation is large, high levels of UV-B radiation tends to reduce plant growth in sensitive species, while CO 2 enrichment tends to promote growth in most C 3 species. However, most previous studies have not looked at temporal effects or at the relationship between photosynthetic acclimation to CO 2 and possible photosynthetic limitations imposed by UV-B radiation. Elevated CO 2 may provide some protection against UV-B for some species. In contrast, UV-B radiation may limit the ability to exploit elevated CO 2 in other species. Interactions between the effects of CO 2 enrichment and UV-B radiation exposure have also been shown for biomass allocation. Effects on both biomass allocation and photosynthetic acclimation may be important to ecosystem structure in terms of seedling establishment, competition and reproductive output. Few studies have evaluated ecosystem processes such as decomposition or nutrient cycling. Interactive effects may be subtle and species specific but should not be ignored in the assessment of the potential impacts of increases in CO 2 and UV-B radiation on plants. (author)

  14. Spatial–temporal changes in runoff and terrestrial ecosystem water retention under 1.5 and 2 °C warming scenarios across China

    Directory of Open Access Journals (Sweden)

    R. Zhai

    2018-06-01

    Full Text Available The Paris Agreement set a long-term temperature goal of holding the global average temperature increase to below 2.0 °C above pre-industrial levels, pursuing efforts to limit this to 1.5 °C; it is therefore important to understand the impacts of climate change under 1.5 and 2.0 °C warming scenarios for climate adaptation and mitigation. Here, climate scenarios from four global circulation models (GCMs for the baseline (2006–2015, 1.5, and 2.0 °C warming scenarios (2106–2115 were used to drive the validated Variable Infiltration Capacity (VIC hydrological model to investigate the impacts of global warming on runoff and terrestrial ecosystem water retention (TEWR across China at a spatial resolution of 0.5°. This study applied ensemble projections from multiple GCMs to provide more comprehensive and robust results. The trends in annual mean temperature, precipitation, runoff, and TEWR were analyzed at the grid and basin scale. Results showed that median change in runoff ranged from 3.61 to 13.86 %, 4.20 to 17.89 %, and median change in TEWR ranged from −0.45 to 6.71 and −3.48 to 4.40 % in the 10 main basins in China under 1.5 and 2.0 °C warming scenarios, respectively, across all four GCMs. The interannual variability of runoff increased notably in areas where it was projected to increase, and the interannual variability increased notably from the 1.5 to the 2.0 °C warming scenario. In contrast, TEWR would remain relatively stable, the median change in standard deviation (SD of TEWR ranged from −10 to 10 % in about 90 % grids under 1.5 and 2.0 °C warming scenarios, across all four GCMs. Both low and high runoff would increase under the two warming scenarios in most areas across China, with high runoff increasing more. The risks of low and high runoff events would be higher under the 2.0 than under the 1.5 °C warming scenario in terms of both extent and intensity. Runoff was significantly positively

  15. Spatial-temporal changes in runoff and terrestrial ecosystem water retention under 1.5 and 2 °C warming scenarios across China

    Science.gov (United States)

    Zhai, Ran; Tao, Fulu; Xu, Zhihui

    2018-06-01

    The Paris Agreement set a long-term temperature goal of holding the global average temperature increase to below 2.0 °C above pre-industrial levels, pursuing efforts to limit this to 1.5 °C; it is therefore important to understand the impacts of climate change under 1.5 and 2.0 °C warming scenarios for climate adaptation and mitigation. Here, climate scenarios from four global circulation models (GCMs) for the baseline (2006-2015), 1.5, and 2.0 °C warming scenarios (2106-2115) were used to drive the validated Variable Infiltration Capacity (VIC) hydrological model to investigate the impacts of global warming on runoff and terrestrial ecosystem water retention (TEWR) across China at a spatial resolution of 0.5°. This study applied ensemble projections from multiple GCMs to provide more comprehensive and robust results. The trends in annual mean temperature, precipitation, runoff, and TEWR were analyzed at the grid and basin scale. Results showed that median change in runoff ranged from 3.61 to 13.86 %, 4.20 to 17.89 %, and median change in TEWR ranged from -0.45 to 6.71 and -3.48 to 4.40 % in the 10 main basins in China under 1.5 and 2.0 °C warming scenarios, respectively, across all four GCMs. The interannual variability of runoff increased notably in areas where it was projected to increase, and the interannual variability increased notably from the 1.5 to the 2.0 °C warming scenario. In contrast, TEWR would remain relatively stable, the median change in standard deviation (SD) of TEWR ranged from -10 to 10 % in about 90 % grids under 1.5 and 2.0 °C warming scenarios, across all four GCMs. Both low and high runoff would increase under the two warming scenarios in most areas across China, with high runoff increasing more. The risks of low and high runoff events would be higher under the 2.0 than under the 1.5 °C warming scenario in terms of both extent and intensity. Runoff was significantly positively correlated to precipitation, while increase in maximum

  16. Characteristic of pollution with groundwater inflow (90)Sr natural waters and terrestrial ecosystems near a radioactive waste storage.

    Science.gov (United States)

    Lavrentyeva, G V

    2014-09-01

    The studies were conducted in the territory contaminated by (90)Sr with groundwater inflow as a result of leakage from the near-surface trench-type radioactive waste storage. The vertical soil (90)Sr distribution up to the depth of 2-3 m is analyzed. The area of radioactive contamination to be calculated with a value which exceeds the minimum significant activity 1 kBq/kg for the tested soil layers: the contaminated area for the 0-5 cm soil layer amounted to 1800 ± 85 m(2), for the 5-10 cm soil layer amounted to 300 ± 12 m(2), for the 10-15 cm soil layer amounted to 180 ± 10 m(2). It is found that (90)Sr accumulation proceeds in a natural sorption geochemical barrier of the marshy terrace near flood plain. The exposure doses for terrestrial mollusks Bradybaena fruticum are presented. The excess (90)Sr interference level was registered both in the ground and surface water during winter and summer low-water periods and autumn heavy rains. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Does temperature and oxygen affect duration of intramarsupial development and juvenile growth in the terrestrial isopod Porcellio scaber (Crustacea, Malacostraca?

    Directory of Open Access Journals (Sweden)

    Terézia Horváthová

    2015-07-01

    Full Text Available According to the temperature-size rule (TSR, ectotherms developing under cold conditions experience slower growth as juveniles but reach a larger size at maturity. Whether temperature alone causes this phenomenon is unknown, but oxygen limitation can play a role in the temperature-size relationship. Oxygen may become limited under warm conditions when the resulting higher metabolism creates a greater demand for oxygen, especially in larger individuals. We examined the independent effects of oxygen concentration (10% and 22% O2 and temperature (15 °C and 22 °C on duration of ontogenic development, which takes place within the maternal brood pouch (marsupium, and juvenile growth in the terrestrial isopod common rough woodlouse (Porcellio scaber. Individuals inside the marsupium undergo the change from the aqueous to the gaseous environment. Under hypoxia, woodlice hatched from the marsupium sooner, but their subsequent growth was not affected by the level of oxygen. Marsupial development and juvenile growth were almost three times slower at low temperature, and marsupial development was longer in larger females but only in the cold treatment. These results show that temperature and oxygen are important ecological factors affecting developmental time and that the strength of the effect likely depends on the availability of oxygen in the environment.

  18. Degradation of mangroves adversely affected ecosystem and rural inhabitant in the Sindh's coastal area

    International Nuclear Information System (INIS)

    Naqvi, S.R.; Inam, Z.

    2005-01-01

    Mangroves the ecological treasure of Sindh, are facing a steady decline due to in active Government policies and lack of interest of local people. Mangroves provide important breeding Zone of to the marine biodiversity because of the reduction of silt flows, the area of active growth of delta, has been reduced from an original estimate of 2600 sq km to about 260 sq km. Similarly, the area of Mangroves from 345,000 hectares, the area is now only 205000 hectares. Pakistani Mangroves rank 6th among the mangroves spread in 92 countries. Mangroves forests act as inter face b/w land and sea. It provides nutrients to marine fisheries and is vital healthy Ecosystem. During past 50 years, nearly 100,000 hectares have been destroyed. The destruction is quite high from 1975 to 1992. It is due to water shortage in the river Indus. Degradation of mangroves adversely affected ecosystem and rural inhabitant in the coastal area. Thus to find root causes of degradation and its effects this study was made. (author)

  19. Ecosystem services as a common language for coastal ecosystem-based management.

    Science.gov (United States)

    Granek, Elise F; Polasky, Stephen; Kappel, Carrie V; Reed, Denise J; Stoms, David M; Koch, Evamaria W; Kennedy, Chris J; Cramer, Lori A; Hacker, Sally D; Barbier, Edward B; Aswani, Shankar; Ruckelshaus, Mary; Perillo, Gerardo M E; Silliman, Brian R; Muthiga, Nyawira; Bael, David; Wolanski, Eric

    2010-02-01

    Ecosystem-based management is logistically and politically challenging because ecosystems are inherently complex and management decisions affect a multitude of groups. Coastal ecosystems, which lie at the interface between marine and terrestrial ecosystems and provide an array of ecosystem services to different groups, aptly illustrate these challenges. Successful ecosystem-based management of coastal ecosystems requires incorporating scientific information and the knowledge and views of interested parties into the decision-making process. Estimating the provision of ecosystem services under alternative management schemes offers a systematic way to incorporate biogeophysical and socioeconomic information and the views of individuals and groups in the policy and management process. Employing ecosystem services as a common language to improve the process of ecosystem-based management presents both benefits and difficulties. Benefits include a transparent method for assessing trade-offs associated with management alternatives, a common set of facts and common currency on which to base negotiations, and improved communication among groups with competing interests or differing worldviews. Yet challenges to this approach remain, including predicting how human interventions will affect ecosystems, how such changes will affect the provision of ecosystem services, and how changes in service provision will affect the welfare of different groups in society. In a case study from Puget Sound, Washington, we illustrate the potential of applying ecosystem services as a common language for ecosystem-based management.

  20. Biodiversity, Community and Trophic Structure of the Suprabenthos of the Gulf of Cádiz-Guadalquivir Estuary Coupled System: Linking Pelagic-Benthic and Terrestrial-Marine Ecosystems.

    Science.gov (United States)

    Vilas, C.

    2016-02-01

    Suprabenthos biodiversity and species densities on both offshore and coastal systems are largely unknown. Main components like mysids, euphasiids or amphipods are omnivorous and constitute a major dietary component for many benthic and pelagic fishes, mammals, cephalopods and decapods. Despite their relevant ecological role linking pelagic-benthic food webs, suprabenthos have been chronically undersampled and their components underrepresented and underestimated in food web models. Many pelagic and demersal species of high commercial and ecological interest at the Gulf of Cádiz (GoC) feed at a bottom scattering layer identified from 0 to 200 m depth and up to 50 km from coast, related to the Guadalquivir Estuary (GE) influence coastal area, and present life history cycles based on a sequential use of habitats from GoC to GE nursery area, may be adapted to match the horizontal migrations of key suprabenthos prey species. In order to understand the ecological mechanisms through which the GE-GoC coupled ecosystem would influence the recruitment of these fishery resources, the suprabenthos was sampled by suprabenthic sldege (200 μm) from the shallow estuary to 75 m depth during June, August and November of 2013. We identified up to 300 species (H index 0.4-2-9 and Beta diversity 0.55), being copepods, molluscs, cumacea, cladocera, poliquets, decapods, mysids and amphipods the most important groups by biomass (mg/m3), finding densities up to 32.9 mg/m3 for copepods, 6 for mysids and up to 100 mg/m3 for decapods. Multivariate analysis determines depth as the most important variable explaining community structure, decreasing biodiversity with depth, while for sites at depths species show seasonal horizontal migrations between GoC and GE, connecting terrestrial and marine ecosystems.

  1. Neoarchean paleoweathering of tonalite and metabasalt: Implications for reconstructions of 2.69Ga early terrestrial ecosystems and paleoatmospheric chemistry

    Science.gov (United States)

    Driese, S.G.; Jirsa, M.A.; Ren, M.; Brantley, S.L.; Sheldon, N.D.; Parker, Dana C.; Schmitz, M.

    2011-01-01

    primitive microbial community) during weathering. Cu metal in the profile may document lower pO2 than present day at the surface. Comparison with previous studies of weathered tonalite and basalt (Denison, 2.45-2.22Ga) in Ontario, Canada, reveal general similarities in paleoweathering with our study, as well as important differences related to lower paleoatmospheric pO2 and terrestrial biosignature for the older Minnesota profile. A falling water table in the Alpine Lake locality is presumed to have promoted formation of this gossan-like deep-weathering system that extends to 50-m depth. ?? 2011 Elsevier B.V.

  2. Glyphosate herbicide affects belowground interactions between earthworms and symbiotic mycorrhizal fungi in a model ecosystem

    Science.gov (United States)

    Zaller, Johann G.; Heigl, Florian; Ruess, Liliane; Grabmaier, Andrea

    2014-01-01

    Herbicides containing glyphosate are widely used in agriculture and private gardens, however, surprisingly little is known on potential side effects on non-target soil organisms. In a greenhouse experiment with white clover we investigated, to what extent a globally-used glyphosate herbicide affects interactions between essential soil organisms such as earthworms and arbuscular mycorrhizal fungi (AMF). We found that herbicides significantly decreased root mycorrhization, soil AMF spore biomass, vesicles and propagules. Herbicide application and earthworms increased soil hyphal biomass and tended to reduce soil water infiltration after a simulated heavy rainfall. Herbicide application in interaction with AMF led to slightly heavier but less active earthworms. Leaching of glyphosate after a simulated rainfall was substantial and altered by earthworms and AMF. These sizeable changes provide impetus for more general attention to side-effects of glyphosate-based herbicides on key soil organisms and their associated ecosystem services. PMID:25005713

  3. Proliferation of MISS-related microbial mats following the end-Permian mass extinction in terrestrial ecosystems: Evidence from the Lower Triassic of the Yiyang area, Henan Province, North China

    Science.gov (United States)

    Tu, Chenyi; Chen, Zhong-Qiang; Retallack, Gregory J.; Huang, Yuangeng; Fang, Yuheng

    2016-03-01

    Microbially induced sedimentary structures (MISSs) are commonly present in siliciclastic shallow marine settings following the end-Permian mass extinction, but have been rarely reported in the post-extinction terrestrial ecosystems. Here, we present six types of well-preserved MISSs from the upper Sunjiagou Formation and lower Liujiagou Formation of Induan (Early Triassic) age in the Yiyang area, Henan Province, North China. These MISSs include: polygonal sand cracks, worm-like structures, wrinkle structures, sponge pore fabrics, gas domes, and leveled ripple marks. Microanalysis shows that these MISSs are characterized by thin clayey laminae and filamentous mica grains arranged parallel to bedding plane as well as oriented matrix supported quartz grains, which are indicative of biogenic origin. Facies analysis suggests that the MISS-hosting sediments were deposited in a fluvial sedimentary system during the Early Triassic, including lake delta, riverbeds/point bars, and flood plain paleoenvironments. Abundant MISSs from Yiyang indicate that microbes also proliferated in terrestrial ecosystems in the aftermath of the Permian-Triassic (P-Tr) biocrisis, like they behaved in marine ecosystems. Microbial blooms, together with dramatic loss of metazoans, may reflect environmental stress and degradation of terrestrial ecosystems or arid climate immediately after the severe Permian-Triassic ecologic crisis.

  4. Occurrence of perchloroethylene in surface water and fish in a river ecosystem affected by groundwater contamination.

    Science.gov (United States)

    Wittlingerová, Zdena; Macháčková, Jiřina; Petruželková, Anna; Zimová, Magdalena

    2016-03-01

    Long-term monitoring of the content of perchloroethylene (PCE) in a river ecosystem affected by groundwater contamination was performed at a site in the Czech Republic. The quality of surface water was monitored quarterly between 1994 and 2013, and fish were collected from the affected ecosystem to analyse the content of PCE in their tissue in 1998, 2011 and 2012. Concentrations of PCE (9-140 μg/kg) in the tissue of fish collected from the contaminated part of the river were elevated compared to the part of the river unaffected by the contamination (ND to 5 μg/kg PCE). The quality of surface water has improved as a result of groundwater remediation during the evaluated period. Before the remedial action, PCE concentrations ranged from 30 to 95 μg/L (1994-1997). Following commencement of remedial activities in September 1997, a decrease in the content of PCE in the surface water to 7.3 μg/L (1998) and further to 1 μg/L (2011) and 1.1 μg/L (2012) led to a progressive decrease in the average concentration of PCE in the fish muscle tissue from 79 μg/kg (1998) to 24 (2011) and 30 μg/kg (2012), respectively. It was determined that the bioconcentration of PCE does not have a linear dependence because the decrease in contamination in the fish muscle tissue is not directly proportional to the decrease in contamination in the river water. The observed average bioconcentration factors were 24 and 28 for the lower concentrations of PCE and 11 for the higher concentrations of PCE in the river. In terms of age, length and weight of the collected fish, weight had the greatest significance for bioconcentration, followed by the length, with age being evaluated as a less significant factor.

  5. Introduction - The impacts of the 2008 eruption of Kasatochi Volcano on terrestrial and marine ecosystems in the Aleutian Islands, Alaska

    Science.gov (United States)

    DeGange, Anthony R.; Byrd, G. Vernon; Walker, Lawrence R.; Waythomas, C.F.

    2010-01-01

    The Aleutian Islands are situated on the northern edge of the so-called “Pacific Ring of Fire,” a 40,000-km-long horseshoe-shaped assemblage of continental landmasses and islands bordering the Pacific Ocean basin that contains many of the world's active and dormant volcanoes. Schaefer et al. (2009) listed 27 historically active volcanoes in the Aleutian Islands, of which nine have had at least one major eruptive event since 1990. Volcanic eruptions are often significant natural disturbances, and ecosystem responses to volcanic eruptions may vary markedly with eruption style (effusive versus explosive), frequency, and magnitude of the eruption as well as isolation of the disturbed sites from potential colonizing organisms (del Moral and Grishin, 1999). Despite the relatively high frequency of volcanic activity in the Aleutians, the response of island ecosystems to volcanic disturbances is largely unstudied because of the region's isolation. The only ecological studies in the region that address the effects of volcanic activity were done on Bogoslof Island, a remote, highly active volcanic island in the eastern Aleutians, which grew from a submarine eruption in 1796 (Merriam, 1910; Byrd et al., 1980; Byrd and Williams, 1994). Nevertheless, in the 214 years of Bogoslof's existence, the island has been visited only intermittently.Kasatochi Island is a small (2.9 km by 2.6 km, 314 m high) volcano in the central Aleutian Islands of Alaska (52.17°N latitude, 175.51°W longitude; Fig. 1) that erupted violently on 7-8 August 2008 after a brief, but intense period of precursory seismic activity (Scott et al., 2010 [this issue]; Waythomas et al., in review). The island is part of the Aleutian arc volcanic front, and is an isolated singular island. Although the immediate offshore areas are relatively shallow (20–50 m water depth), the island is about 10 km south of the 2000 m isobath, north of which, ocean depths increase markedly. Kasatochi is located between the

  6. Climate change consequences for terrestrial ecosystem processes in NW Greeland: Results from the High Arctic Biocomplexity project

    Science.gov (United States)

    Welker, J. M.; Sullivan, P.; Rogers, M.; Sharp, E. D.; Sletten, R.; Burnham, J. L.; Hallet, B.; Hagedorn, B.; Czimiczk, C.

    2009-12-01

    Greenland is experiencing some of the fastest rates of climate warming across the Arctic including warmer summers and increases in snow fall. The effects of these new states of Greenland are however, uncertain especially for carbon, nitrogen and water biogeochemical processes, soil traits, vegetation growth patterns, mineral nutrition and plant ecophysiological processes. Since 2003 we have conducted a suite of observational and experimental measurements that have been designed to understand the fundamental nature of polar desert, polar semi-desert and fen landscapes in NW Greenland. In addition, we have established a suite of experiments to ascertain ecosystem responses to warming at multiple levels (~2030 and 2050), in conjunction with added summer rain; the consequences of added snow fall (ambient, intermediate and deep) and the effects of increases in nutrient additions (added N, P and N+P), which represent extreme warming conditions. We find that: a) the soil C pools are 6-fold larger than previously measured, b) extremely old C (up to ~30k bp) which has been buried by frost cracking and frost heaving is reaching the modern atmosphere, but in only trace amounts as measured by respired 14CO2, c) warming that simulates 2030, has only a small effect on net C sequestration but warming that simulates 2050 when combined with added summer rain, increases C sequestration by 300%, d) increases in N deposition almost immediately and completely changes the vegetation composition of polar semi-deserts shifting the NDVI values from 0.2 to 0.5 within 2 years. Our findings depict a system that is poised to contribute stronger feedbacks than previously expected as climates in NW Greenland change.

  7. The Importance of Uncertainty and Sensitivity Analysis in Process-based Models of Carbon and Nitrogen Cycling in Terrestrial Ecosystems with Particular Emphasis on Forest Ecosystems — Selected Papers from a Workshop Organized by the International Society for Ecological Modelling (ISEM) at the Third Biennal Meeting of the International Environmental Modelling and Software Society (IEMSS) in Burlington, Vermont, USA, August 9-13, 2006

    Science.gov (United States)

    Larocque, Guy R.; Bhatti, Jagtar S.; Liu, Jinxun; Ascough, James C.; Gordon, Andrew M.

    2008-01-01

    Many process-based models of carbon (C) and nitrogen (N) cycles have been developed for terrestrial ecosystems, including forest ecosystems. They address many basic issues of ecosystems structure and functioning, such as the role of internal feedback in ecosystem dynamics. The critical factor in these phenomena is scale, as these processes operate at scales from the minute (e.g. particulate pollution impacts on trees and other organisms) to the global (e.g. climate change). Research efforts remain important to improve the capability of such models to better represent the dynamics of terrestrial ecosystems, including the C, nutrient, (e.g. N) and water cycles. Existing models are sufficiently well advanced to help decision makers develop sustainable management policies and planning of terrestrial ecosystems, as they make realistic predictions when used appropriately. However, decision makers must be aware of their limitations by having the opportunity to evaluate the uncertainty associated with process-based models (Smith and Heath, 2001 and Allen et al., 2004). The variation in scale of issues currently being addressed by modelling efforts makes the evaluation of uncertainty a daunting task.

  8. EcoDoses. Improving radiological assessment of doses to man from terrestrial ecosystems. A status report for the NKS-B project 2004

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, Sven P.; Isaksson, M.; Nilsson, Elisabeth (and others)

    2005-07-01

    The NKS B-programme EcoDoses project started in 2003 as a collaboration between all the Nordic countries. The aim of the project is to improve the radiological assessments of doses to man from terrestrial ecosystems. The present report sums up the work performed in the second phase of the project. The main topics in 2004 have been: (i) A continuation of previous work with a better approach for estimating global fallout on a regional or national scale, based on a correlation between precipitation and deposition rates. (ii) Fur-ther extension of the EcoDoses milk database. Estimation of effective ecological half lives of {sup 137}Cs in cows milk focussing on suitable post-Chernobyl time-series. Modelling integrated transfer of {sup 13}7{sup C}s to cow's milk from Nordic countries. (iii) Determination of effective ecological half lives for fresh water fish from Nordic lakes. (iv) Investigate ra-dioecological sensitivity for Nordic populations. (v) Food-chain modelling using the Eco-sys-model, which is the underlying food- and dose-module in several computerised deci-sion-making systems. (au)

  9. Depletion of stratospheric ozone over the Antarctic and Arctic: Responses of plants of polar terrestrial ecosystems to enhanced UV-B, an overview

    International Nuclear Information System (INIS)

    Rozema, Jelte; Boelen, Peter; Blokker, Peter

    2005-01-01

    Depletion of stratospheric ozone over the Antarctic has been re-occurring yearly since 1974, leading to enhanced UV-B radiation. Arctic ozone depletion has been observed since 1990. Ozone recovery has been predicted by 2050, but no signs of recovery occur. Here we review responses of polar plants to experimentally varied UV-B through supplementation or exclusion. In supplementation studies comparing ambient and above ambient UV-B, no effect on growth occurred. UV-B-induced DNA damage, as measured in polar bryophytes, is repaired overnight by photoreactivation. With UV exclusion, growth at near ambient may be less than at below ambient UV-B levels, which relates to the UV response curve of polar plants. UV-B screening foils also alter PAR, humidity, and temperature and interactions of UV with environmental factors may occur. Plant phenolics induced by solar UV-B, as in pollen, spores and lignin, may serve as a climate proxy for past UV. Since the Antarctic and Arctic terrestrial ecosystems differ essentially (e.g. higher species diversity and more trophic interactions in the Arctic), generalization of polar plant responses to UV-B needs caution. - Polar plant responses to UV-B may be different in the Arctic than Antarctic regions

  10. EcoDoses. Improving radiological assessment of doses to man from terrestrial ecosystems. A status report for the NKS-B project 2004

    International Nuclear Information System (INIS)

    Nielsen, Sven P.; Isaksson, M.; Nilsson, Elisabeth

    2005-07-01

    The NKS B-programme EcoDoses project started in 2003 as a collaboration between all the Nordic countries. The aim of the project is to improve the radiological assessments of doses to man from terrestrial ecosystems. The present report sums up the work performed in the second phase of the project. The main topics in 2004 have been: (i) A continuation of previous work with a better approach for estimating global fallout on a regional or national scale, based on a correlation between precipitation and deposition rates. (ii) Fur-ther extension of the EcoDoses milk database. Estimation of effective ecological half lives of 137 Cs in cows milk focussing on suitable post-Chernobyl time-series. Modelling integrated transfer of 13 7 C s to cow's milk from Nordic countries. (iii) Determination of effective ecological half lives for fresh water fish from Nordic lakes. (iv) Investigate ra-dioecological sensitivity for Nordic populations. (v) Food-chain modelling using the Eco-sys-model, which is the underlying food- and dose-module in several computerised deci-sion-making systems. (au)

  11. Contamination of terrestrial ecosystem components with 90Sr, 137Cs, and 226Ra caused by the deterioration of the multibarrier protection of radioactive waste storages

    Science.gov (United States)

    Latynova, N. E.

    2010-03-01

    The spatial-temporal features of the radioactive contamination of terrestrial ecosystem components caused by the deterioration of the multibarrier protection of regional radioactive waste storages of the State Research Center of the Russian Federation-Leipunskii Institute of Physics and Power Engineering at the input of radionuclides into the soil and ground water were studied. The composition of the radioactive contamination was determined, and the hydrological and geochemical processes resulting in the formation of large radioactive sources were described. The natural features of the radioactive waste storage areas favoring the entry of 90Sr, 137Cs, and 226Ra into the soils and their inclusion in the biological turnover were characterized. The directions of the horizontal migration of 90Sr, 137Cs, and 226Ra and the sites of their accumulation within the superaquatic and aquatic landscapes of a near-terrace depression were studied; the factors of the 90Sr accumulation in plants and cockles were calculated. The results of the studies expand the theoretical concepts of the mechanisms, processes, and factors controlling the behavior of radionuclides at the deterioration of the multibarrier protection of radioactive waste storages. The presented experimental data can be used for solving practical problems related to environmental protection in the areas of industrial nuclear complexes.

  12. Assessing the Impacts of forest degradation on water, energy, and carbon budgets in Amazon forest using the Functionally Assembled Terrestrial Ecosystem Simulator

    Science.gov (United States)

    Huang, M.; Xu, Y.; Longo, M.; Keller, M.; Knox, R. G.; Koven, C.; Fisher, R.

    2017-12-01

    Tropical forest degradation from logging, fire, and fragmentation not only alters carbon stocks and carbon fluxes, but also impacts physical land-surface properties such as albedo and roughness length. Such impacts are poorly quantified to date due to difficulties in accessing and maintaining observational infrastructures, and the lack of proper modeling tools for capturing the interactions among biophysical properties, ecosystem demography, and biogeochemical cycling in tropical forests. As a first step to address these limitations, we implemented a selective logging module into the Functional Assembled Terrestrial Ecosystem Simulator (FATES) and parameterized the model to reproduce the selective logging experiment at the Tapajos National Forest in Brazil. The model was spun up until it reached the steady state, and simulations with and without logging were compared with the eddy covariance flux towers located at the logged and intact sites. The sensitivity of simulated water, energy, and carbon fluxes to key plant functional traits (e.g. Vcmax and leaf longevity) were quantified by perturbing their values within their documented ranges. Our results suggest that the model can reproduce water and carbon fluxes in intact forests, although sensible heat fluxes were overestimated. The effects of logging intensity and techniques on fluxes were assessed by specifying different disturbance parameters in the models (e.g., size-dependent mortality rates associated with timber harvest, collateral damage, and mechanical damage for infrastructure construction). The model projections suggest that even though the degraded forests rapidly recover water and energy fluxes compared with old-growth forests, the recovery times for carbon stocks, forest structure and composition are much longer. In addition, the simulated recovery trajectories are highly dependent on choices of values for functional traits. Our study highlights the advantages of an Earth system modeling approach

  13. Quantification of anthropogenic impact on groundwater-dependent terrestrial ecosystem using geochemical and isotope tools combined with 3-D flow and transport modelling

    Science.gov (United States)

    Zurek, A. J.; Witczak, S.; Dulinski, M.; Wachniew, P.; Rozanski, K.; Kania, J.; Postawa, A.; Karczewski, J.; Moscicki, W. J.

    2015-02-01

    Groundwater-dependent ecosystems (GDEs) have important functions in all climatic zones as they contribute to biological and landscape diversity and provide important economic and social services. Steadily growing anthropogenic pressure on groundwater resources creates a conflict situation between nature and man which are competing for clean and safe sources of water. Such conflicts are particularly noticeable in GDEs located in densely populated regions. A dedicated study was launched in 2010 with the main aim to better understand the functioning of a groundwater-dependent terrestrial ecosystem (GDTE) located in southern Poland. The GDTE consists of a valuable forest stand (Niepolomice Forest) and associated wetland (Wielkie Błoto fen). It relies mostly on groundwater from the shallow Quaternary aquifer and possibly from the deeper Neogene (Bogucice Sands) aquifer. In July 2009 a cluster of new pumping wells abstracting water from the Neogene aquifer was set up 1 km to the northern border of the fen. A conceptual model of the Wielkie Błoto fen area for the natural, pre-exploitation state and for the envisaged future status resulting from intense abstraction of groundwater through the new well field was developed. The main aim of the reported study was to probe the validity of the conceptual model and to quantify the expected anthropogenic impact on the studied GDTE. A wide range of research tools was used. The results obtained through combined geologic, geophysical, geochemical, hydrometric and isotope investigations provide strong evidence for the existence of upward seepage of groundwater from the deeper Neogene aquifer to the shallow Quaternary aquifer supporting the studied GDTE. Simulations of the groundwater flow field in the study area with the aid of a 3-D flow and transport model developed for Bogucice Sands (Neogene) aquifer and calibrated using environmental tracer data and observations of hydraulic head in three different locations on the study area

  14. Quantifying causal mechanisms to determine how protected areas affect poverty through changes in ecosystem services and infrastructure

    Science.gov (United States)

    Ferraro, Paul J.; Hanauer, Merlin M.

    2014-01-01

    To develop effective environmental policies, we must understand the mechanisms through which the policies affect social and environmental outcomes. Unfortunately, empirical evidence about these mechanisms is limited, and little guidance for quantifying them exists. We develop an approach to quantifying the mechanisms through which protected areas affect poverty. We focus on three mechanisms: changes in tourism and recreational services; changes in infrastructure in the form of road networks, health clinics, and schools; and changes in regulating and provisioning ecosystem services and foregone production activities that arise from land-use restrictions. The contributions of ecotourism and other ecosystem services to poverty alleviation in the context of a real environmental program have not yet been empirically estimated. Nearly two-thirds of the poverty reduction associated with the establishment of Costa Rican protected areas is causally attributable to opportunities afforded by tourism. Although protected areas reduced deforestation and increased regrowth, these land cover changes neither reduced nor exacerbated poverty, on average. Protected areas did not, on average, affect our measures of infrastructure and thus did not contribute to poverty reduction through this mechanism. We attribute the remaining poverty reduction to unobserved dimensions of our mechanisms or to other mechanisms. Our study empirically estimates previously unidentified contributions of ecotourism and other ecosystem services to poverty alleviation in the context of a real environmental program. We demonstrate that, with existing data and appropriate empirical methods, conservation scientists and policymakers can begin to elucidate the mechanisms through which ecosystem conservation programs affect human welfare. PMID:24567397

  15. Engineer pioneer plants respond to and affect geomorphic constraints similarly along water–terrestrial interfaces world-wide

    OpenAIRE

    Corenblit, D.; Baas, A.; Balke, T.; Bouma, T.J.; Fromard, F.; Garófano-Gómez, V.; González, E.; Gurnell, A.M.; Hortobágyi, B.; Julien, F.; Kim, D.; Lambs, L.; Stallins, J.A.; Steiger, J.; Tabacchi, E.

    2015-01-01

    Aim Within fluvial and coastal ecosystems world-wide, flows of water, wind and sediment generate a shifting landscape mosaic composed of bare substrate and pioneer and mature vegetation successional stages. Pioneer plant species that colonize these ecosystems at the land–water interface have developed specific traits in response to environmental constraints (response...

  16. Working group 7: Ecosystems

    International Nuclear Information System (INIS)

    Verheyen, R.

    1976-01-01

    The purpose of this article is to evaluate the environmental impact of nuclear power plants. The effects of ionizing radiations, of the thermal and chemical pollution on aquatic ecosystems as well as on terrestrial ecosystems have been estimated. After a general survey of such effects and their interaction, practical conclusions in regard to determined areas such as Meuse-Escaut marine and the coast have been drawn. The contamination effects of food chains have been evaluted under deliberately pessimistic conditions with regard to the choice of the radionuclide as well as of concentration factors. Following the biodegradation conditions of the surface waters, criteria for the quality of the aquatic ecosystems have been established. Finally, attention has been paid on certain factors affecting the site selection especially within the frame of the nature conservation. The effects of cooling towers have been also considered. (G.C.)

  17. The influence of grain size, grain color, and suspended-sediment concentration on light attenuation: why fine-grained terrestrial sediment is bad for coral reef ecosystems

    Science.gov (United States)

    Storlazzi, Curt; Norris, Benjamin; Rosenberger, Kurt

    2015-01-01

    Sediment has been shown to be a major stressor to coral reefs globally. Although many researchers have tested the impact of sedimentation on coral reef ecosystems in both the laboratory and the field and some have measured the impact of suspended sediment on the photosynthetic response of corals, there has yet to be a detailed investigation on how properties of the sediment itself can affect light availability for photosynthesis. We show that finer-grained and darker-colored sediment at higher suspended-sediment concentrations attenuates photosynthetically active radiation (PAR) significantly more than coarser, lighter-colored sediment at lower concentrations and provide PAR attenuation coefficients for various grain sizes, colors, and suspended-sediment concentrations that are needed for biophysical modeling. Because finer-grained sediment particles settle more slowly and are more susceptible to resuspension, they remain in the water column longer, thus causing greater net impact by reducing light essential for photosynthesis over a greater duration. This indicates that coral reef monitoring studies investigating sediment impacts should concentrate on measuring fine-grained lateritic and volcanic soils, as opposed to coarser-grained siliceous and carbonate sediment. Similarly, coastal restoration efforts and engineering solutions addressing long-term coral reef ecosystem health should focus on preferentially retaining those fine-grained soils rather than coarse silt and sand particles.

  18. Guidelines for Terrestrial Ecosystem Survey.

    Science.gov (United States)

    1980-05-01

    25 deer inhabiting forest edge. When deer populations in other habitats are determined, the size of the deer herd can be approximated. In preparing...total deer herd also can be judged. Site Selection An area should be chosen for survey from maps completed in Stages I and II on potential habitat and...Southwood, T. R. E., Ecological Methods (London: Methuen, 1966). Spencer, D. A., " Porcupine Population Fluctuations in Past Centuries Revealed by

  19. Plant species and functional group combinations affect green roof ecosystem functions.

    Science.gov (United States)

    Lundholm, Jeremy; Macivor, J Scott; Macdougall, Zachary; Ranalli, Melissa

    2010-03-12

    Green roofs perform ecosystem services such as summer roof temperature reduction and stormwater capture that directly contribute to lower building energy use and potential economic savings. These services are in turn related to ecosystem functions performed by the vegetation layer such as radiation reflection and transpiration, but little work has examined the role of plant species composition and diversity in improving these functions. We used a replicated modular extensive (shallow growing- medium) green roof system planted with monocultures or mixtures containing one, three or five life-forms, to quantify two ecosystem services: summer roof cooling and water capture. We also measured the related ecosystem properties/processes of albedo, evapotranspiration, and the mean and temporal variability of aboveground biomass over four months. Mixtures containing three or five life-form groups, simultaneously optimized several green roof ecosystem functions, outperforming monocultures and single life-form groups, but there was much variation in performance depending on which life-forms were present in the three life-form mixtures. Some mixtures outperformed the best monocultures for water capture, evapotranspiration, and an index combining both water capture and temperature reductions. Combinations of tall forbs, grasses and succulents simultaneously optimized a range of ecosystem performance measures, thus the main benefit of including all three groups was not to maximize any single process but to perform a variety of functions well. Ecosystem services from green roofs can be improved by planting certain life-form groups in combination, directly contributing to climate change mitigation and adaptation strategies. The strong performance by certain mixtures of life-forms, especially tall forbs, grasses and succulents, warrants further investigation into niche complementarity or facilitation as mechanisms governing biodiversity-ecosystem functioning relationships in green

  20. Ecological transfer mechanisms - Terrestrial

    International Nuclear Information System (INIS)

    Martin, W.E.; Raines, Gilbert E.; Bloom, S.G.; Levin, A.A.

    1969-01-01

    Radionuclides produced by nuclear excavation detonations and released to the environment may enter a variety of biogeochemical cycles and follow essentially the same transfer pathways as their stable-element counterparts. Estimation of potential internal radiation doses to individuals and/or populations living in or near fallout-contaminated areas requires analysis of the food-chain and other ecological pathways by which radionuclides released to the environment may be returned to man. A generalized materials transfer diagram, applicable to the forest, agricultural, freshwater and marine ecosystems providing food and water to the indigenous population of Panama and Colombia in regions that could be affected by nuclear excavation of a sea-level canal between the Atlantic and Pacific Oceans, is presented. Transfer mechanisms effecting the movement of stable elements and radionuclides in terrestrial ecosystems are discussed, and methods used to simulate these processes by means of mathematical models are described to show how intake values are calculated for different radionuclides in the major ecological pathways leading to man. These data provide a basis for estimating potential internal radiation doses for comparison with the radiation protection criteria established by recognized authorities; and this, in turn, provides a basis for recommending measures to insure the radiological safety of the nuclear operation plan. (author)

  1. Ecological transfer mechanisms - Terrestrial

    Energy Technology Data Exchange (ETDEWEB)

    Martin, W E; Raines, Gilbert E; Bloom, S G; Levin, A A [Battelle Memorial Institute, CoIumbus, OH (United States)

    1969-07-01

    Radionuclides produced by nuclear excavation detonations and released to the environment may enter a variety of biogeochemical cycles and follow essentially the same transfer pathways as their stable-element counterparts. Estimation of potential internal radiation doses to individuals and/or populations living in or near fallout-contaminated areas requires analysis of the food-chain and other ecological pathways by which radionuclides released to the environment may be returned to man. A generalized materials transfer diagram, applicable to the forest, agricultural, freshwater and marine ecosystems providing food and water to the indigenous population of Panama and Colombia in regions that could be affected by nuclear excavation of a sea-level canal between the Atlantic and Pacific Oceans, is presented. Transfer mechanisms effecting the movement of stable elements and radionuclides in terrestrial ecosystems are discussed, and methods used to simulate these processes by means of mathematical models are described to show how intake values are calculated for different radionuclides in the major ecological pathways leading to man. These data provide a basis for estimating potential internal radiation doses for comparison with the radiation protection criteria established by recognized authorities; and this, in turn, provides a basis for recommending measures to insure the radiological safety of the nuclear operation plan. (author)

  2. Physiological Integration Affects Expansion of an Amphibious Clonal Plant from Terrestrial to Cu-Polluted Aquatic Environments

    Science.gov (United States)

    Xu, Liang; Zhou, Zhen-Feng

    2017-03-01

    The effects of physiological integration on clonal plants growing in aquatic and terrestrial habitats have been extensively studied, but little is known about the role in the extension of amphibious clonal plants in the heterogeneous aquatic-terrestrial ecotones, especially when the water environments are polluted by heavy metals. Ramets of the amphibious clonal herb Alternanthera philoxeroides were rooted in unpolluted soil and polluted water at three concentrations of Cu. The extension of populations from unpolluted terrestrial to polluted aqueous environments mainly relied on stem elongation rather than production of new ramets. The absorbed Cu in the ramets growing in polluted water could be spread horizontally to other ramets in unpolluted soil via physiological integration and redistributed in different organs. The performances of ramets in both terrestrial and aquatic habitats were negatively correlated with Cu intensities in different organs of plants. It is concluded that physiological integration might lessen the fitness of connected ramets in heterogeneously polluted environments. The mechanical strength of the stems decreased with increasing Cu levels, especially in polluted water. We suggest that, except for direct toxicity to growth and expansion, heavy metal pollution might also increase the mechanical risk in breaking failure of plants.

  3. How clear-cutting affects fire severity and soil properties in a Mediterranean ecosystem.

    Science.gov (United States)

    Francos, Marcos; Pereira, Paulo; Mataix-Solera, Jorge; Arcenegui, Victoria; Alcañiz, Meritxell; Úbeda, Xavier

    2018-01-15

    Forest management practices in Mediterranean ecosystems are frequently employed to reduce both the risk and severity of wildfires. However, these pre-fire treatments may influence the effects of wildfire events on soil properties. The aim of this study is to examine the short-term effects of a wildfire that broke out in 2015 on the soil properties of three sites: two exposed to management practices in different years - 2005 (site M05B) and 2015 (site M15B) - and one that did not undergo any management (NMB) and to compare their properties with those recorded in a plot (Control) unaffected by the 2015 wildfire. We analyzed aggregate stability (AS), soil organic matter (SOM) content, total nitrogen (TN), carbon/nitrogen ratio (C/N), inorganic carbon (IC), pH, electrical conductivity (EC), extractable calcium (Ca), magnesium (Mg), sodium (Na), and potassium (K), microbial biomass carbon (C mic ) and basal soil respiration (BSR). In the managed plots, a clear-cutting operation was conducted, whereby part of the vegetation was cut and left covering the soil surface. The AS values recorded at the Control site were significantly higher than those recorded at M05B, whereas the TN and SOM values at NMB were significantly higher than those recorded at M05B. IC was significantly higher at M05B than at the other plots. There were no significant differences in C/N ratio between the analyzed sites. Soil pH at M05B was significantly higher than the value recorded at the Control plot. Extractable Ca was significantly higher at NMB than at both M05B and the Control, while extractable Mg was significantly lower at M05B than at NMB. Extractable K was significantly lower at the Control than at the three fire-affected plots. C mic was significantly higher at NMB than at the Control. BSR, BSR/C and BSR/C mic values at the fire-affected sites were significantly lower than those recorded at the Control. No significant differences were identified in C mic /C. Overall, a comparison of the

  4. Estimation of biogenic volatile organic compound (BVOC) emissions from the terrestrial ecosystem in China using real-time remote sensing data

    Science.gov (United States)

    Li, M.; Huang, X.; Li, J.; Song, Y.

    2012-04-01

    Because of the high emission intensity and reactivity, biogenic volatile organic compounds (BVOCs) play a significant role in the terrestrial ecosystems, human health, secondary pollution, global climate change and the global carbon cycle. Past estimations of BVOC emissions in China were based on outdated algorithms and limited meteorological data, and there have been significant inconsistences between the land surface parameters of dynamic models and those of BVOC estimation models, leading to large inaccuracies in the estimated results. To refine BVOC emission estimations for China and to further explore the role of BVOCs in atmospheric chemical processes, we used the latest algorithms of MEGAN (Model of Emissions of Gases and Aerosols from Nature) with MM5 (the Fifth-Generation Mesoscale Model) providing highly resolved meteorological data, to estimate the biogenic emissions of isoprene (C5H8) and seven monoterpene species (C10H16) in 2006. Real-time MODIS (Moderate Resolution Imaging Spectroradiometer) data were introduced to update the land surface parameters and improve the simulation performance of MM5, and to modify the influence of leaf area index (LAI) and leaf age deviation from standard conditions. In this study, the annual BVOC emissions for the whole country totaled 12.97 Tg C, a relevant value much lower than that given in global estimations but higher than the past estimations in China. Therein, the most important individual contributor was isoprene (9.36 Tg C), followed by α-pinene (1.24 Tg C yr-1) and β-pinene (0.84 Tg C yr-1). Due to the considerable regional disparity in plant distributions and meteorological conditions across China, BVOC emissions presented significant spatial-temporal variations. Spatially, isoprene emission was concentrated in South China, which is covered by large areas of broadleaf forests and shrubs. On the other hand, Southeast China was the top-ranking contributor of monoterpenes, in which the dominant vegetation

  5. Solidago canadensis invasion affects soil N-fixing bacterial communities in heterogeneous landscapes in urban ecosystems in East China.

    Science.gov (United States)

    Wang, Congyan; Jiang, Kun; Zhou, Jiawei; Wu, Bingde

    2018-03-12

    Soil nitrogen-fixing bacterial communities (SNB) can increase the level of available soil N via biological N-fixation to facilitate successful invasion of several invasive plant species (IPS). Meanwhile, landscape heterogeneity can greatly enhance regional invasibility and increase the chances of successful invasion of IPS. Thus, it is important to understand the soil micro-ecological mechanisms driving the successful invasion of IPS in heterogeneous landscapes. This study performed cross-site comparisons, via metagenomics, to comprehensively analyze the effects of Solidago canadensis invasion on SNB in heterogeneous landscapes in urban ecosystems. Rhizospheric soil samples of S. canadensis were obtained from nine urban ecosystems [Three replicate quadrats (including uninvaded sites and invaded sites) for each type of urban ecosystem]. S. canadensis invasion did not significantly affect soil physicochemical properties, the taxonomic diversity of plant communities, or the diversity and richness of SNB. However, some SNB taxa (i.e., f_Micromonosporaceae, f_Oscillatoriaceae, and f_Bacillaceae) changed significantly with S. canadensis invasion. Thus, S. canadensis invasion may alter the community structure, rather than the diversity and richness of SNB, to facilitate its invasion process. Of the nine urban ecosystems, the diversity and richness of SNB was highest in farmland wasteland. Accordingly, the community invasibility of farmland wasteland may be higher than that of the other types of urban ecosystem. In brief, landscape heterogeneity, rather than S. canadensis invasion, was the strongest controlling factor for the diversity and richness of SNB. One possible reason may be the differences in soil electrical conductivity and the taxonomic diversity of plant communities in the nine urban ecosystems, which can cause notable shifts in the diversity and richness of SNB. Copyright © 2018 Elsevier B.V. All rights reserved.

  6. Assessing how green space types affect ecosystem services delivery in Porto, Portugal

    Science.gov (United States)

    Marisa Graça; Paulo Alves; João Gonçalves; David J. Nowak; Robert Hoehn; Paulo Farinha-Marques; Mario Cunha

    2018-01-01

    Significant advances have been made in identifying, quantifying and valuing multiple urban ecosystem services (UES), yet this knowledge remains poorly implemented in urban planning and management. One of the reasons for this low implementation is the insufficient thematic and spatial detail in UES research to provide guidance for urban planners and managers....

  7. Terrestrial forest management plan for Palmyra Atoll

    Science.gov (United States)

    Hathaway, Stacie A.; McEachern, Kathryn; Fisher, Robert N.

    2011-01-01

    , and though rarely documented, beach nesting could be affected by terrestrial management actions. There are various nonnative or invasive species throughout the terrestrial ecosystem. The most notable examples of terrestrial invasive species include coconut palms (Cocos nucifera) and black rats (Rattus rattus). Although it is unclear whether they are nonnative, coconut palms are currently the most dominant plant across Palmyra Atoll. They compete with native plant species for space and resources and are potentially detrimental to sea birds dependent on native vegetation for roosting and nesting habitat. This competition in turn impacts nutrient resource availability, thereby reshaping energy flow in the ecosystem. Black rats are known to prey on ground-nesting sea birds and are likely responsible for the lack of burrowing sea bird reproduction at Palmyra Atoll. In addition, they may be facilitating the invasion of other nonnative species and negatively impacting other native fauna. Although the extent and impacts of these and other nonnative and (or) invasive species are not fully understood, the extent and impacts are clearly a threat to the native species and one of the most urgent threats to the overall ecosystem integrity of Palmyra Atoll. This 'Terrestrial Forest Management Plan for Palmyra Atoll' addresses issues related to invasive species and other problems. Priority goals are established as are associated objectives and strategies. The overarching goal is to perpetuate and where possible restore terrestrial ecosystem integrity through the following techniques: 1. Habitat management: Maintain and enhance habitat to the extent possible to sustain thriving Pisonia grandis forest, coastal strand forest, endemic grassland, self-sustaining populations of sea birds, shore birds, coconut crabs, native lizards, and native insects. 2. Monitoring and assessment: Acquire information on distribution and abundance as needed for conservation of each resour

  8. Effects of red-backed salamanders on ecosystem functions.

    Directory of Open Access Journals (Sweden)

    Daniel J Hocking

    Full Text Available Ecosystems provide a vast array of services for human societies, but understanding how various organisms contribute to the functions that maintain these services remains an important ecological challenge. Predators can affect ecosystem functions through a combination of top-down trophic cascades and bottom-up effects on nutrient dynamics. As the most abundant vertebrate predator in many eastern US forests, woodland salamanders (Plethodon spp. likely affect ecosystems functions. We examined the effects of red-backed salamanders (Plethodon cinereus on a variety of forest ecosystem functions using a combined approach of large-scale salamander removals (314-m(2 plots and small-scale enclosures (2 m(2 where we explicitly manipulated salamander density (0, 0.5, 1, 2, 4 m(-2. In these experiments, we measured the rates of litter and wood decomposition, potential nitrogen mineralization and nitrification rates, acorn germination, and foliar insect damage on red oak seedlings. Across both experimental venues, we found no significant effect of red-backed salamanders on any of the ecosystem functions. We also found no effect of salamanders on intraguild predator abundance (carabid beetles, centipedes, spiders. Our study adds to the already conflicting evidence on effects of red-backed salamander and other amphibians on terrestrial ecosystem functions. It appears likely that the impact of terrestrial amphibians on ecosystem functions is context dependent. Future research would benefit from explicitly examining terrestrial amphibian effects on ecosystem functions under a variety of environmental conditions and in different forest types.

  9. Effects of red-backed salamanders on ecosystem functions.

    Science.gov (United States)

    Hocking, Daniel J; Babbitt, Kimberly J

    2014-01-01

    Ecosystems provide a vast array of services for human societies, but understanding how various organisms contribute to the functions that maintain these services remains an important ecological challenge. Predators can affect ecosystem functions through a combination of top-down trophic cascades and bottom-up effects on nutrient dynamics. As the most abundant vertebrate predator in many eastern US forests, woodland salamanders (Plethodon spp.) likely affect ecosystems functions. We examined the effects of red-backed salamanders (Plethodon cinereus) on a variety of forest ecosystem functions using a combined approach of large-scale salamander removals (314-m(2) plots) and small-scale enclosures (2 m(2)) where we explicitly manipulated salamander density (0, 0.5, 1, 2, 4 m(-2)). In these experiments, we measured the rates of litter and wood decomposition, potential nitrogen mineralization and nitrification rates, acorn germination, and foliar insect damage on red oak seedlings. Across both experimental venues, we found no significant effect of red-backed salamanders on any of the ecosystem functions. We also found no effect of salamanders on intraguild predator abundance (carabid beetles, centipedes, spiders). Our study adds to the already conflicting evidence on effects of red-backed salamander and other amphibians on terrestrial ecosystem functions. It appears likely that the impact of terrestrial amphibians on ecosystem functions is context dependent. Future research would benefit from explicitly examining terrestrial amphibian effects on ecosystem functions under a variety of environmental conditions and in different forest types.

  10. 'One physical system': Tansley's ecosystem as Earth's critical zone.

    Science.gov (United States)

    Richter, Daniel deB; Billings, Sharon A

    2015-05-01

    Integrative concepts of the biosphere, ecosystem, biogeocenosis and, recently, Earth's critical zone embrace scientific disciplines that link matter, energy and organisms in a systems-level understanding of our remarkable planet. Here, we assert the congruence of Tansley's (1935) venerable ecosystem concept of 'one physical system' with Earth science's critical zone. Ecosystems and critical zones are congruent across spatial-temporal scales from vegetation-clad weathering profiles and hillslopes, small catchments, landscapes, river basins, continents, to Earth's whole terrestrial surface. What may be less obvious is congruence in the vertical dimension. We use ecosystem metabolism to argue that full accounting of photosynthetically fixed carbon includes respiratory CO₂ and carbonic acid that propagate to the base of the critical zone itself. Although a small fraction of respiration, the downward diffusion of CO₂ helps determine rates of soil formation and, ultimately, ecosystem evolution and resilience. Because life in the upper portions of terrestrial ecosystems significantly affects biogeochemistry throughout weathering profiles, the lower boundaries of most terrestrial ecosystems have been demarcated at depths too shallow to permit a complete understanding of ecosystem structure and function. Opportunities abound to explore connections between upper and lower components of critical-zone ecosystems, between soils and streams in watersheds, and between plant-derived CO₂ and deep microbial communities and mineral weathering. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  11. How forest management affects ecosystem services, including timber production and economic return

    DEFF Research Database (Denmark)

    Duncker, Philipp S.; Raulund-Rasmussen, Karsten; Gundersen, Per

    2012-01-01

    and services. By use of virtual but realistic datasets, we quantified, for multiple services, the effects of five forest management alternatives that form an intensity gradient. Our virtual forest management units represented Central European forest ecosystems in the submontane vegetation zone under a humid......–temperate climate with acidic soils. In this zone the European beech (Fagus sylvatica L.) is the dominant tree species. In order to assess the effects on ecosystem services, the untouched natural forest reserve served as a reference. Wherever possible, response functions were deduced to couple the various services...... via stand-level data to demonstrate trade-offs between the services. Management units comprised all development phases in the sense of a "normal forest". It was clearly illustrated that maximizing the rates of biomass production and carbon sequestration may conflict with protection of authentic...

  12. Carbon exchange between ecosystems and atmosphere in the Czech Republic is affected by climate factors

    Czech Academy of Sciences Publication Activity Database

    Marek, Michal V.; Janouš, Dalibor; Taufarová, Klára; Havránková, Kateřina; Pavelka, Marian; Kaplan, Věroslav; Marková, I.

    2011-01-01

    Roč. 159, č. 5 (2011), s. 1035-1039 ISSN 0269-7491 R&D Projects: GA MŽP(CZ) SP/1A6/108/07; GA MŠk 2B06068 Institutional research plan: CEZ:AV0Z60870520 Keywords : carbon fluxes * net ecosystem exchange * spruce forest * beech forest * Grassland * agroecosystem * wetland * climate factors Subject RIV: EH - Ecology, Behaviour Impact factor: 3.746, year: 2011

  13. How climate affects ecosystems: A Canadian perspective on what we know

    International Nuclear Information System (INIS)

    Rowe, S.; Rizzo, B.

    1990-01-01

    The effects of climate change on ecosystems is discussed from the Canadian perspective. After a brief definition of terms, the implications of ecosystem theory are elaborated on. Impact models generated from altered climatic regimes can be categorized into two methodological streams: correlation modelling and dynamic modelling. Correlation modelling characterizes change on the basis of transfer functions linking climatic parameters and indices to specific ecological units. Correlation models can be applied at the species level or at the broader ecosystem level. Dynamic models are based on life history characteristics from birth to death, tracking such details as plant abundance, height and leaf area. Such models are most useful at the local rather than global scale. In Canada a number of broad scale correlation models have been attempted. These include the potential impacts of climatic change in the Praire provinces and Northwest Territories, a study relating the growing degree day isolines to ecological boundaries established in the ecoclimatic regions of Canada map, and the incorporation of nine climatic parameters in a correlation exercise, again using the ecoclimatic regions map. 14 refs

  14. Assessment of the importance of acidic fogwater and cloudwater in affecting terrestrial vegetation: Some important case studies

    Energy Technology Data Exchange (ETDEWEB)

    Irving, P.M.; Eagar, C. (National Acid Precipitation Assessment Program, Washington, DC (USA). Office of the Director of Research; Forest Service, Broomall, PA (USA). Northeastern Forest Experiment Station)

    1989-01-01

    The purpose of this paper is to present some examples of terrestrial effects of concern as case studies to demonstrate the methodology to be used for answering questions of the NAPAP Integrated Assessment. The two examples presented, one each for forestry and crops, represent what is probably the worst case'' for possible acidic rain effects on crops and forests. Both examples revolve around hypotheses centering on stress from acidic fogwater or cloudwater. Because it is likely that additional information will become available prior to the publication of the Integrated Assessment, it should be understood that the analyses and interpretations presented on the following pages are subject to change when NAPAP publishes its final Assessment in 1990. 76 refs., 3 tabs.

  15. Riparian vegetation in the alpine connectome: Terrestrial-aquatic and terrestrial-terrestrial interactions.

    Science.gov (United States)

    Zaharescu, Dragos G; Palanca-Soler, Antonio; Hooda, Peter S; Tanase, Catalin; Burghelea, Carmen I; Lester, Richard N

    2017-12-01

    Alpine regions are under increased attention worldwide for their critical role in early biogeochemical cycles, their high sensitivity to environmental change, and as repositories of natural resources of high quality. Their riparian ecosystems, at the interface between aquatic and terrestrial environments, play important geochemical functions in the watershed and are biodiversity hotspots, despite a harsh climate and topographic setting. With climate change rapidly affecting the alpine biome, we still lack a comprehensive understanding of the extent of interactions between riparian surface, lake and catchment environments. A total of 189 glacial - origin lakes were surveyed in the Central Pyrenees to test how key elements of the lake and terrestrial environments interact at different scales to shape riparian plant composition. Secondly, we evaluated how underlying ecotope features drive the formation of natural communities potentially sensitive to environmental change and assessed their habitat distribution. At the macroscale, vegetation composition responded to pan-climatic gradients altitude and latitude, which captured in a narrow geographic area the transition between large European climatic zones. Hydrodynamics was the main catchment-scale factor connecting riparian vegetation with major water fluxes, followed by topography and geomorphology. Lake sediment Mg and Pb, and water Mn and Fe contents reflected local influences from mafic bedrock and soil water saturation. Community analysis identified four keystone ecosystems: (i) damp ecotone, (ii) snow bed-silicate bedrock, (iii) wet heath, and (iv) calcareous substrate. These communities and their connections with ecotope elements could be at risk from a number of environmental change factors including warmer seasons, snow line and lowland species advancement, increased nutrient/metal input and water level fluctuations. The results imply important natural terrestrial-aquatic linkages in the riparian environment

  16. Anthropogenic pollutants affect ecosystem services of freshwater sediments. The need for a 'triad plus x' approach

    Energy Technology Data Exchange (ETDEWEB)

    Gerbersdorf, Sabine Ulrike; Wieprecht, Silke [Stuttgart Univ. (Germany). Dept. of Hydraulic Engineering and Water Resources Management; Hollert, Henner; Brinkmann, Markus [RWTH Aachen Univ. (Germany). Dept. of Ecosystem Analysis; Schuettrumpf, Holger [RWTH Aachen Univ. (Germany). Inst. of Hydraulic Engineering and Water Resources Management; Manz, Werner [Koblenz-Landau Univ., Koblenz (Germany). Inst. for Integrated Natural Sciences

    2011-09-15

    Purpose: Freshwater sediments and their attached microbial communities (biofilms) are essential features of rivers and lakes, providing valuable ecosystem services such as nutrient recycling or self-purification which extend beyond the aquatic environment. Anthropogenic pollutants, whether from the industrial era or as a result of our contemporary lifestyles, can negatively affect these functions with hitherto unknown consequences on ecology, the economy and human health. Thus far, the singular view of the involved disciplines such as ecotoxicology, environmental microbiology, hydrology and geomorphology has prevented a deeper understanding of this emerging issue. Main features: This paper discusses briefly the progressions and the state-of-the-art methods within the disciplines of concern related to contaminated sediments, ranging from ecotoxicological test systems, microbiological/molecular approaches to unravel changes of microbial ecosystems, up to the modelling of sediment transport and sorption/desorption of associated pollutants. The first bilateral research efforts on contaminated sediments include efforts to assess ecotoxicological sediment risk including sediment mobility (i.e. ecotoxicology and engineering), enhance bioremediation potential (i.e. microbiology and ecotoxicology) or to understand biostabilisation processes of sediments by microbial assemblages (i.e. microbiology and engineering). Conclusions and perspectives: In freshwater habitats, acute, chronic and mechanism-specific toxic effects on organisms, shifts in composition, structure and functionality of benthic microbial communities, as well as the obstruction of important ecosystem services by continuously discharged and long-deposited pollutants, should be related to the in situ sediment dynamics. To achieve an improved understanding of the ecology of freshwater sediments and the impairment of their important ecosystem functions by human-derived pollutants, we suggest a 'triad plus x

  17. Changes in canopy structure and ant assemblages affect soil ecosystem variables as a foundation species declines

    DEFF Research Database (Denmark)

    Kendrick, Joseph A.; Ribbons, Relena Rose; Classen, Aimee Taylor

    2015-01-01

    in ant species composition would interact to alter soil ecosystem variables. In the Harvard Forest Hemlock Removal Experiment (HF-HeRE), established in 2003, T. canadensis in large plots were killed in place or logged and removed to mimic adelgid infestation or salvage harvesting, respectively. In 2006...... (richness and abundance) of ants increases rapidly as T. canadensis is lost from the stands. Because ants live and forage at the litter-soil interface, we hypothesized that environmental changes caused by hemlock loss (e.g., increased light and warmth at the forest floor, increased soil pH) and shifts......, we built ant exclosure subplots within all of the canopy manipulation plots to examine direct and interactive effects of canopy change and ant assemblage composition on soil and litter variables. Throughout HF-HeRE, T. canadensis was colonized by the adelgid in 2009, and the infested trees are now...

  18. Distribution of polychlorinated biphenyls in an urban riparian zone affected by wastewater treatment plant effluent and the transfer to terrestrial compartment by invertebrates.

    Science.gov (United States)

    Yu, Junchao; Wang, Thanh; Han, Shanlong; Wang, Pu; Zhang, Qinghua; Jiang, Guibin

    2013-10-01

    In this study, we investigated the distribution of polychlorinated biphenyls (PCBs) in a riparian zone affected by the effluent from a wastewater treatment plant (WWTP). River water, sediment, aquatic invertebrates and samples from the surrounding terrestrial compartment such as soil, reed plants and several land based invertebrates were collected. A relatively narrow range of δ(13)C values was found among most invertebrates (except butterflies, grasshoppers), indicating a similar energy source. The highest concentration of total PCBs was observed in zooplankton (151.1 ng/g lipid weight), and soil dwelling invertebrates showed higher concentrations than phytophagous insects at the riparian zone. The endobenthic oligochaete Tubifex tubifex (54.28 ng/g lw) might be a useful bioindicator of WWTP derived PCBs contamination. High bioaccumulation factors (BAFs) were observed in collected aquatic invertebrates, although the biota-sediment/soil accumulation factors (BSAF) remained relatively low. Emerging aquatic insects such as chironomids could carry waterborne PCBs to the terrestrial compartment via their lifecycles. The estimated annual flux of PCBs for chironomids ranged from 0.66 to 265 ng⋅m(-2)⋅y(-1). Although a high prevalence of PCB-11 and PCB-28 was found for most aquatic based samples in this riparian zone, the mid-chlorinated congeners (e.g. PCB-153 and PCB-138) became predominant among chironomids and dragonflies as well as soil dwelling invertebrates, which might suggest a selective biodriven transfer of different PCB congeners. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. Earthworm functional traits and interspecific interactions affect plant nitrogen acquisition and primary production

    NARCIS (Netherlands)

    Andriuzzi, Walter; Schmidt, Olaf; Brussaard, L.; Faber, J.H.; Bolger, T.

    2016-01-01

    We performed a greenhouse experiment to test how the functional diversity of earthworms, the dominant group of soil macro-invertebrates in many terrestrial ecosystems, affects nitrogen cycling and plant growth. Three species were chosen to represent a range of functional traits: Lumbricus terrestris

  20. Concentration and retention of Toxoplasma gondii oocysts by marine snails demonstrate a novel mechanism for transmission of terrestrial zoonotic pathogens in coastal ecosystems

    Science.gov (United States)

    Krusor, Colin; Smith, Woutrina A.; Tinker, M. Tim; Silver, Mary; Conrad, Patricia A.; Shapiro, Karen

    2015-01-01

    The parasite Toxoplasma gondii is an environmentally persistent pathogen that can cause fatal disease in humans, terrestrial warm-blooded animals and aquatic mammals. Although an association between T. gondii exposure and prey specialization on marine snails was identified in threatened California sea otters, the ability of kelp-dwelling snails to transmit terrestrially derived pathogens has not been previously investigated. The objective of this study was to measure concentration and retention of T. gondii by marine snails in laboratory aquaria, and to test for natural T. gondii contamination in field-collected snails. Following exposure to T. gondii-containing seawater, oocysts were detected by microscopy in snail faeces and tissues for 10 and 3 days respectively. Nested polymerase chain reaction was also applied as a method for confirming putative T. gondii oocysts detected in snail faeces and tissues by microscopy. Toxoplasma gondiiwas not detected in field-collected snails. Results suggest that turban snails are competent transport hosts for T. gondii. By concentrating oocysts in faecal pellets, snails may facilitate entry of T. gondii into the nearshore marine food web. This novel mechanism also represents a general pathway by which marine transmission of terrestrially derived microorganisms can be mediated via pathogen concentration and retention by benthic invertebrates.

  1. Environmental research programme. Ecological research. Annual report 1995. Urban-industrial landscapes, forests, agricultural landscapes, river and lake landscapes, terrestrial ecosystem research, environmental pollution and health

    International Nuclear Information System (INIS)

    1996-01-01

    In promoting ecology research, the federal ministry of science and technology (BMBF) pursues the aim to enhance understanding of the natural resources indispensable to the life of man, animals and plant societies and their interrelations, and to point out existing scope for action to preserve or replenish them. Consequently, ecology research makes an essential contribution towards effective nature conservancy and environmental protection. The interactions between climate and ecosystems also form an important part of this. With regard to topical environmental issues concerning agricultural landscapes, rivers and lakes, forests and urban-industrial agglomerations, system interrelations in representative ecosystems are investigated. The results are to be embodied in directives for the protection or appropriate use of these ecosystems in order to contribute towards a sustainable development of these types of landscapes. The book also evaluates and assesses which types of nuisances, interventions and modes of use represent hazards for the respective systems. (orig./VHE) [de

  2. Distribution of polychlorinated biphenyls in an urban riparian zone affected by wastewater treatment plant effluent and the transfer to terrestrial compartment by invertebrates

    International Nuclear Information System (INIS)

    Yu, Junchao; Wang, Thanh; Han, Shanlong; Wang, Pu; Zhang, Qinghua; Jiang, Guibin

    2013-01-01

    In this study, we investigated the distribution of polychlorinated biphenyls (PCBs) in a riparian zone affected by the effluent from a wastewater treatment plant (WWTP). River water, sediment, aquatic invertebrates and samples from the surrounding terrestrial compartment such as soil, reed plants and several land based invertebrates were collected. A relatively narrow range of δ 13 C values was found among most invertebrates (except butterflies, grasshoppers), indicating a similar energy source. The highest concentration of total PCBs was observed in zooplankton (151.1 ng/g lipid weight), and soil dwelling invertebrates showed higher concentrations than phytophagous insects at the riparian zone. The endobenthic oligochaete Tubifex tubifex (54.28 ng/g lw) might be a useful bioindicator of WWTP derived PCBs contamination. High bioaccumulation factors (BAFs) were observed in collected aquatic invertebrates, although the biota-sediment/soil accumulation factors (BSAF) remained relatively low. Emerging aquatic insects such as chironomids could carry waterborne PCBs to the terrestrial compartment via their lifecycles. The estimated annual flux of PCBs for chironomids ranged from 0.66 to 265 ng⋅m −2 ⋅y −1 . Although a high prevalence of PCB-11 and PCB-28 was found for most aquatic based samples in this riparian zone, the mid-chlorinated congeners (e.g. PCB-153 and PCB-138) became predominant among chironomids and dragonflies as well as soil dwelling invertebrates, which might suggest a selective biodriven transfer of different PCB congeners. Highlights: • The distribution of PCBs in an urban riparian zone around a wastewater effluent affected river was investigated. • Relatively high abundances of PCB-11 and PCB-28 were found for most samples. • Mid-chlorinated congeners (PCB-153 and PCB-138) were more accumulated in chironomids and dragonflies as well as soil dwelling invertebrates. • Emerging invertebrates can carry waterborne PCBs to the terrestrial

  3. Distribution of polychlorinated biphenyls in an urban riparian zone affected by wastewater treatment plant effluent and the transfer to terrestrial compartment by invertebrates

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Junchao [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085 (China); Environment Research Institute, Shandong University, Jinan, 250100 (China); Wang, Thanh, E-mail: bswang@rcees.ac.cn [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085 (China); Han, Shanlong [Environment Research Institute, Shandong University, Jinan, 250100 (China); Wang, Pu; Zhang, Qinghua; Jiang, Guibin [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085 (China)

    2013-10-01

    In this study, we investigated the distribution of polychlorinated biphenyls (PCBs) in a riparian zone affected by the effluent from a wastewater treatment plant (WWTP). River water, sediment, aquatic invertebrates and samples from the surrounding terrestrial compartment such as soil, reed plants and several land based invertebrates were collected. A relatively narrow range of δ{sup 13}C values was found among most invertebrates (except butterflies, grasshoppers), indicating a similar energy source. The highest concentration of total PCBs was observed in zooplankton (151.1 ng/g lipid weight), and soil dwelling invertebrates showed higher concentrations than phytophagous insects at the riparian zone. The endobenthic oligochaete Tubifex tubifex (54.28 ng/g lw) might be a useful bioindicator of WWTP derived PCBs contamination. High bioaccumulation factors (BAFs) were observed in collected aquatic invertebrates, although the biota-sediment/soil accumulation factors (BSAF) remained relatively low. Emerging aquatic insects such as chironomids could carry waterborne PCBs to the terrestrial compartment via their lifecycles. The estimated annual flux of PCBs for chironomids ranged from 0.66 to 265 ng⋅m{sup −2}⋅y{sup −1}. Although a high prevalence of PCB-11 and PCB-28 was found for most aquatic based samples in this riparian zone, the mid-chlorinated congeners (e.g. PCB-153 and PCB-138) became predominant among chironomids and dragonflies as well as soil dwelling invertebrates, which might suggest a selective biodriven transfer of different PCB congeners. Highlights: • The distribution of PCBs in an urban riparian zone around a wastewater effluent affected river was investigated. • Relatively high abundances of PCB-11 and PCB-28 were found for most samples. • Mid-chlorinated congeners (PCB-153 and PCB-138) were more accumulated in chironomids and dragonflies as well as soil dwelling invertebrates. • Emerging invertebrates can carry waterborne PCBs to the

  4. Integrating a process-based ecosystem model with Landsat imagery to assess impacts of forest disturbance on terrestrial carbon dynamics: Case studies in Alabama and Mississippi

    Science.gov (United States)

    Forest ecosystems in the southern United States are dramatically altered by three major 26 disturbances: timber harvesting, hurricane, and permanent land conversion. Understanding and quantifying effects of disturbance on forest carbon, nitrogen, and water cycles is critical for sustainable forest m...

  5. Glomalin in a mediterranean ecosystem affected by mining activities and its contribution to heavy metals sequestration

    Energy Technology Data Exchange (ETDEWEB)

    Cornejo, P.; Meier, F.; Borie, G.; Borie, F.

    2009-07-01

    Glomalin-related soil protein (GRSP), a glycoprotein produced by arbuscular mycorrhizal fungi (AMF) and usually presents in high amounts in soil, may stabilize heavy metals such as Cu an Zn in soils affected by mining activities, as large areas of central Chile. (Author)

  6. Estimates of phytomass and net primary productivity in terrestrial ecosystems of the former Soviet Union identified by classified Global Vegetation Index

    Energy Technology Data Exchange (ETDEWEB)

    Gaston, G.G.; Kolchugina, T.P. [Oregon State Univ., Corvallis, OR (United States)

    1995-12-01

    Forty-two regions with similar vegetation and landcover were identified in the former Soviet Union (FSU) by classifying Global Vegetation Index (GVI) images. Image classes were described in terms of vegetation and landcover. Image classes appear to provide more accurate and precise descriptions for most ecosystems when compared to general thematic maps. The area of forest lands were estimated at 1,330 Mha and the actual area of forest ecosystems at 875 Mha. Arable lands were estimated to be 211 Mha. The area of the tundra biome was estimated at 261 Mha. The areas of the forest-tundra/dwarf forest, taiga, mixed-deciduous forest and forest-steppe biomes were estimated t 153, 882, 196, and 144 Mha, respectively. The areas of desert-semidesert biome and arable land with irrigated land and meadows, were estimated at 126 and 237 Mha, respectively. Vegetation and landcover types were associated with the Bazilevich database of phytomass and NPP for vegetation in the FSU. The phytomass in the FSU was estimated at 97.1 Gt C, with 86.8 in forest vegetation, 9.7 in natural non-forest and 0.6 Gt C in arable lands. The NPP was estimated at 8.6 Gt C/yr, with 3.2, 4.8, and 0.6 Gt C/yr of forest, natural non-forest, and arable ecosystems, respectively. The phytomass estimates for forests were greater than previous assessments which considered the age-class distribution of forest stands in the FSU. The NPP of natural ecosystems estimated in this study was 23% greater than previous estimates which used thematic maps to identify ecosystems. 47 refs., 4 figs., 2 tabs.

  7. How sulfate-rich mine drainage affected aquatic ecosystem degradation in northeastern China, and potential ecological risk.

    Science.gov (United States)

    Zhao, Qian; Guo, Fen; Zhang, Yuan; Ma, Shuqin; Jia, Xiaobo; Meng, Wei

    2017-12-31

    Mining activity is an increasingly important stressor for freshwater ecosystems. However, the mechanism on how sulfate-rich mine drainage affects freshwater ecosystems is largely unknown, and its potential ecological risk has not been assessed so far. During 2009-2016, water and macroinvertebrate samples from 405 sample sites were collected along the mine drainage gradient from circum-neutral to alkaline waters in Hun-Tai River, Northeastern China. Results of linear regressions showed that sulfate-rich mine drainage was significantly positively correlated with the constituents typically derived from rock weathering (Ca 2+ , Mg 2+ and HCO 3 - +CO 3 2- ); the diversity of intolerant stream macroinvertebrates exhibited a steep decline along the gradient of sulfate-rich mine drainage. Meanwhile, stressor-response relationships between sulfate-rich mine drainage and macroinvertebrate communities were explored by two complementary statistical approaches in tandem (Threshold Indicator Taxa Analysis and the field-based method developed by USEPA). Results revealed that once stream sulfate concentrations in mine drainage exceeded 35mg/L, significant decline in the abundance of intolerant macroinvertebrate taxa occurred. An assessment of ecological risk posed by sulfate-rich mine drainage was conducted based on a tiered approach consisting of simple deterministic method (Hazard Quotient, HQ) to probabilistic method (Joint Probability Curve, JPC). Results indicated that sulfate-rich mine drainage posed a potential risk, and 64.62-84.88% of surface waters in Hun-Tai River exist serious risk while 5% threshold (HC 05 ) and 1% threshold (HC 01 ) were set up to protect macroinvertebrates, respectively. This study provided us a better understanding on the impacts of sulfate-rich mine drainage on freshwater ecosystems, and it would be helpful for future catchment management to protect streams from mining activity. Copyright © 2017. Published by Elsevier B.V.

  8. Climate change and Southern Ocean ecosystems I: how changes in physical habitats directly affect marine biota.

    Science.gov (United States)

    Constable, Andrew J; Melbourne-Thomas, Jessica; Corney, Stuart P; Arrigo, Kevin R; Barbraud, Christophe; Barnes, David K A; Bindoff, Nathaniel L; Boyd, Philip W; Brandt, Angelika; Costa, Daniel P; Davidson, Andrew T; Ducklow, Hugh W; Emmerson, Louise; Fukuchi, Mitsuo; Gutt, Julian; Hindell, Mark A; Hofmann, Eileen E; Hosie, Graham W; Iida, Takahiro; Jacob, Sarah; Johnston, Nadine M; Kawaguchi, So; Kokubun, Nobuo; Koubbi, Philippe; Lea, Mary-Anne; Makhado, Azwianewi; Massom, Rob A; Meiners, Klaus; Meredith, Michael P; Murphy, Eugene J; Nicol, Stephen; Reid, Keith; Richerson, Kate; Riddle, Martin J; Rintoul, Stephen R; Smith, Walker O; Southwell, Colin; Stark, Jonathon S; Sumner, Michael; Swadling, Kerrie M; Takahashi, Kunio T; Trathan, Phil N; Welsford, Dirk C; Weimerskirch, Henri; Westwood, Karen J; Wienecke, Barbara C; Wolf-Gladrow, Dieter; Wright, Simon W; Xavier, Jose C; Ziegler, Philippe

    2014-10-01

    Antarctic and Southern Ocean (ASO) marine ecosystems have been changing for at least the last 30 years, including in response to increasing ocean temperatures and changes in the extent and seasonality of sea ice; the magnitude and direction of these changes differ between regions around Antarctica that could see populations of the same species changing differently in different regions. This article reviews current and expected changes in ASO physical habitats in response to climate change. It then reviews how these changes may impact the autecology of marine biota of this polar region: microbes, zooplankton, salps, Antarctic krill, fish, cephalopods, marine mammals, seabirds, and benthos. The general prognosis for ASO marine habitats is for an overall warming and freshening, strengthening of westerly winds, with a potential pole-ward movement of those winds and the frontal systems, and an increase in ocean eddy activity. Many habitat parameters will have regionally specific changes, particularly relating to sea ice characteristics and seasonal dynamics. Lower trophic levels are expected to move south as the ocean conditions in which they are currently found move pole-ward. For Antarctic krill and finfish, the latitudinal breadth of their range will depend on their tolerance of warming oceans and changes to productivity. Ocean acidification is a concern not only for calcifying organisms but also for crustaceans such as Antarctic krill; it is also likely to be the most important change in benthic habitats over the coming century. For marine mammals and birds, the expected changes primarily relate to their flexibility in moving to alternative locations for food and the energetic cost of longer or more complex foraging trips for those that are bound to breeding colonies. Few species are sufficiently well studied to make comprehensive species-specific vulnerability assessments possible. Priorities for future work are discussed. © 2014 John Wiley & Sons Ltd.

  9. Characterizing Zinc Speciation in Soils from a Smelter-Affected Boreal Forest Ecosystem.

    Science.gov (United States)

    Hamilton, Jordan G; Farrell, Richard E; Chen, Ning; Feng, Renfei; Reid, Joel; Peak, Derek

    2016-03-01

    HudBay Minerals, Inc., has mined and/or processed Zn and Cu ore in Flin Flon, MB, Canada, since the 1930s. The boreal forest ecosystem and soil surrounding these facilities have been severely impacted by mixed metal contamination and HSO deposition. Zinc is one of the most prevalent smelter-derived contaminants and has been identified as a key factor that may be limiting revegetation. Metal toxicity is related to both total concentrations and speciation; therefore, X-ray absorption spectroscopy and X-ray fluorescence mapping were used to characterize Zn speciation in soils throughout the most heavily contaminated areas of the landscape. Zinc speciation was linked to two distinct soil types. Group I soils consist of exposed soils in weathered positions of bedrock outcrops with Zn present primarily as franklinite, a (ZnFeO) spinel mineral. Group II soils are stabilized by an invasive metal-tolerant grass species, with Zn found as a mixture of octahedral (Fe oxides) and tetrahedral Mn oxides) adsorption complexes with a franklinite component. Soil erosion influences Zn speciation through the redistribution of Zn and soil particulates from Group I landscape positions to Group II soils. Despite Group II soils having the highest concentrations of CaCl-extractable Zn, they support metal-tolerant plant growth. The metal-tolerant plants are probably preferentially colonizing these areas due to better soil and nutrient conditions as a result of soil deposition from upslope Group I areas. Zinc concentration and speciation appears to not influence the colonization by metal-tolerant grasses, but the overall soil properties and erosion effects prevent the revegetation by native boreal forest species. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  10. Environmental and Microbial Features Affecting Denitrification and Anammox Hotspots in an Estuarine Ecosystem

    Science.gov (United States)

    Lisa, J.; Song, B.; Lefcheck, J. S.; Tobias, C. R.

    2016-02-01

    Biogeochemical hotspots are characterized as a few sites that exhibit extremely high reaction rates relative to surrounding area, and often account for a high percentage of the overall reaction rates in an ecosystem. Criteria for quantitatively identifying these sites have not been well established. Further, the underlying mechanisms of hotspots have been described in terms of environmental conditions, with little attention paid to the microbial community. The objectives of this study were to establish quantitative criteria to identify denitrification and anammox hotspots, and determine the underlying microbial and environmental factors responsible for elevated N2 production. We used 15N isotope pairing incubation experiments to measure denitrification and anammox rates in the New River Estuary, NC. Quantitative PCR assays of nitrous oxide reductase (nosZ Clades I and II) and hydrazine oxidoreductase (hzo) genes were conducted to estimate denitrifier and anammox abundance. Structural Equation Modeling (SEM) was used to elucidate complex causal relationships between environmental and biological variables. Denitrification hotspots, quantitatively defined as statistical outliers, accounted for 35.6% total denitrification while comprising only 7.3% of the sites. Anammox hotspots,10.6% of the sites, accounted for 60.9% of total anammox. SEM revealed increased sediment organics at lower salinities supported higher functional gene abundance, which in turn resulted in higher N2 production. Surprisingly, denitrification rates were significantly and positively correlated with nosZ Clade II gene abundance, after accounting for the non-significant contributions of the naturally more abundant nosZ Clade I, and other environmental covariates. This is the first time that a quantitative definition of biogeochemical hotspots was put forth and used to determine the importance of anammox and denitrification hotspots in estuarine nitrogen removal capacity. Despite the low area

  11. [Multi-scenario simulation and prediction of ecosystem services as affected by urban expansion: A case study in coastal area of Tianjin, North China].

    Science.gov (United States)

    Huang, Huan-Chun; Yun, Ying-Xia; Miao, Zhan-Tang; Hao, Cui; Li, Hong-yuan

    2013-03-01

    Based on the modified Logistic-CA model, and taking the coastal area of Tianjin as a case, this paper simulated the spatial evolution patterns of ecosystem services as affected by the urban expansion in 2011-2020 under the scenarios of historical extrapolation, endogenous development, and exogenous development. Overall, the total ecosystem services of the study area under the three scenarios were generally the same, and the functional region with the lowest level ecosystem services had the identical spatial pattern. However, the spatial evolution patterns of the ecosystem services of the study area under the three scenarios had a great difference. The functional regions with lower-level ecosystem services grew in a cross-shaped pattern, with the Tanggu downtown as a center, and finally formed a full connectivity area along the Haihe River and coastal zone.

  12. Trace metallic elements in Helix aspersa terrestrial snails of a semiarid ecosystem; Elementos metalicos traza en caracoles terrestres Helix aspersa de un ecosistema semiarido

    Energy Technology Data Exchange (ETDEWEB)

    Gaso P, M.I.; Segovia, N.; Zarazua, G.; Montes, F. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico); Morton, O.; Armienta, M.A.; Hernandez, E. [IGF-UNAM, Ciudad Universitaria, 04510 Mexico D.F. (Mexico)

    2001-07-01

    The concentration of some major elements and traces in soil samples and of Helix aspersa eatable terrestrial snails were analysed at the Radioactive Wastes Storage Center (CADER) and in other reference sites. The methodology includes the use of an atomic absorption spectrophotometer, an X-ray fluorescence equipment and an Icp-mass spectroscope. The concentrations of some toxic elements (Ba, Cd, Cr, Ni, Pb and V) in the soft tissue of the snails were greater than the toxic levels reported in the literature for such trace elements. The snails compared with another wild eatable foods present transfer coefficients soil-snail high relatively. (Author)

  13. The false promises of coal exploitation: How mining affects herdsmen well-being in the grassland ecosystems of Inner Mongolia

    International Nuclear Information System (INIS)

    Dai, G.S.; Ulgiati, S.; Zhang, Y.S.; Yu, B.H.; Kang, M.Y.; Jin, Y.; Dong, X.B.; Zhang, X.S.

    2014-01-01

    The grasslands of Inner Mongolia are not only the source of the necessary resources for the survival and development of herdsmen, but also represent a significant green ecological barrier in North China. Coal-mining production is important in maintaining GDP growth in Inner Mongolia. However, over-exploitation has created serious problems, such as pollution of the environment and significant decreases in grassland ecosystem services, in addition to impacting the well-being of herdsmen and other humans. Based on questionnaires survey performed among 864 herdsmen addressing the relationship between coal exploitation in grasslands and human well-being in Xilinguole League in Inner Mongolia, we found that (1) coal resource exploitation in these grasslands does not benefit the herdsmen by increasing their income; (2) the rapid development of this resource has not obviously materially improved the life of the herdsmen; and (3) these activities have increased the risks that herdsman will have to endure in the future. Overall, coal resource exploitation in grasslands has more negative than positive effects on the well-being of herdsmen. We propose the conservation of coal resources and improvement of ecological compensation should be carried out without blindly pursuing economic growth, instead of focusing on economic development and structural adjustments. - Highlights: • Evaluation of the human well-being of the Xilinguole grassland, Inner Mongolia, China. • Impact of mining affects herdsmen well-being in grassland ecosystem. • Quantity of questionnaires survey. • Addressing the relationship between coal exploitation in grasslands and human well-being

  14. Reviewing ecosystems affected by the fallout from the Chernobyl reactor accident with respect to the resulting population exposure

    International Nuclear Information System (INIS)

    Fielitz, U.

    1999-01-01

    The research project is intended to yield information on the current radiological situation resulting from the Chernobyl fallout. Environmental materials of particular interest are game, mushrooms, berries, and forest stands in the most heavily affected forest ecosystem of the Bavarian forest area called Bayerischer Wald. This area has been intensively monitored in the period from 1988 until 1994, so that the development up to the current radiological situation can be analysed. Activities under the research project will encompass: Measurement of the radioactive contamination of specimens of the game population in the Bodenmais forest area of 7 500 hectares. Measurement of seasonal variations of the radiocesium activity in various indicator plants of the food chain of the game population. Soil sampling and radioactivity measurement at 2 cm depth intervals. The measuring work will be carried out in two areas which have been earmarked for monitoring over the last eight years (B1 and B2). The measured results will be compared with earlier data, and long-term space and time-dependent information on the transfer of radiocesium in the forest ecosystem under review will be derived. (orig./CB) [de

  15. Radiation Dose Assessment For The Biota Of Terrestrial Ecosystems In The Shoreline Zone Of The Chernobyl Nuclear Power Plant Cooling Pond

    International Nuclear Information System (INIS)

    Farfan, E.; Jannik, T.

    2011-01-01

    Radiation exposure of the biota in the shoreline area of the Chernobyl Nuclear Power Plant Cooling Pond was assessed to evaluate radiological consequences from the decommissioning of the Cooling Pond. The article addresses studies of radioactive contamination of the terrestrial faunal complex and radionuclide concentration ratios in bodies of small birds, small mammals, amphibians, and reptiles living in the area. The data were used to calculate doses to biota using the ERICA Tool software. Doses from 90 Sr and 137 Cs were calculated using the default parameters of the ERICA Tool and were shown to be consistent with biota doses calculated from the field data. However, the ERICA dose calculations for plutonium isotopes were much higher (2-5 times for small mammals and 10-14 times for birds) than the doses calculated using the experimental data. Currently, the total doses for the terrestrial biota do not exceed maximum recommended levels. However, if the Cooling Pond is allowed to drawdown naturally and the contaminants of the bottom sediments are exposed and enter the biological cycle, the calculated doses to biota may exceed the maximum recommended values. The study is important in establishing the current exposure conditions such that a baseline exists from which changes can be documented following the lowering of the reservoir water. Additionally, the study provided useful radioecological data on biota concentration ratios for some species that are poorly represented in the literature.

  16. Ecological impacts of atmospheric pollution and interactions with climate change in terrestrial ecosystems of the Mediterranean Basin: Current research and future directions.

    Science.gov (United States)

    Ochoa-Hueso, Raúl; Munzi, Silvana; Alonso, Rocío; Arróniz-Crespo, María; Avila, Anna; Bermejo, Victoria; Bobbink, Roland; Branquinho, Cristina; Concostrina-Zubiri, Laura; Cruz, Cristina; Cruz de Carvalho, Ricardo; De Marco, Alessandra; Dias, Teresa; Elustondo, David; Elvira, Susana; Estébanez, Belén; Fusaro, Lina; Gerosa, Giacomo; Izquieta-Rojano, Sheila; Lo Cascio, Mauro; Marzuoli, Riccardo; Matos, Paula; Mereu, Simone; Merino, José; Morillas, Lourdes; Nunes, Alice; Paoletti, Elena; Paoli, Luca; Pinho, Pedro; Rogers, Isabel B; Santos, Arthur; Sicard, Pierre; Stevens, Carly J; Theobald, Mark R

    2017-08-01

    Mediterranean Basin ecosystems, their unique biodiversity, and the key services they provide are currently at risk due to air pollution and climate change, yet only a limited number of isolated and geographically-restricted studies have addressed this topic, often with contrasting results. Particularities of air pollution in this region include high O 3 levels due to high air temperatures and solar radiation, the stability of air masses, and dominance of dry over wet nitrogen deposition. Moreover, the unique abiotic and biotic factors (e.g., climate, vegetation type, relevance of Saharan dust inputs) modulating the response of Mediterranean ecosystems at various spatiotemporal scales make it difficult to understand, and thus predict, the consequences of human activities that cause air pollution in the Mediterranean Basin. Therefore, there is an urgent need to implement coordinated research and experimental platforms along with wider environmental monitoring networks in the region. In particular, a robust deposition monitoring network in conjunction with modelling estimates is crucial, possibly including a set of common biomonitors (ideally cryptogams, an important component of the Mediterranean vegetation), to help refine pollutant deposition maps. Additionally, increased attention must be paid to functional diversity measures in future air pollution and climate change studies to establish the necessary link between biodiversity and the provision of ecosystem services in Mediterranean ecosystems. Through a coordinated effort, the Mediterranean scientific community can fill the above-mentioned gaps and reach a greater understanding of the mechanisms underlying the combined effects of air pollution and climate change in the Mediterranean Basin. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Changes in rainfall patterns in Mediterranean ecosystems: the MIND project

    Directory of Open Access Journals (Sweden)

    Papale D

    2007-12-01

    Full Text Available Will Mediterranean terrestrial ecosystems be affected by the expected changes in precipitation regimes? If so, by how much and in which direction? These questions are at the basis of the research performed in context of the EU MIND project, whose key objectives were: i to investigate the potential effects of increasing drought on Mediterranean terrestrial ecosystems at the process, ecosystem and regional scales and ii to assess ecosystem vulnerability to changes in rainfall patterns. A network of experimental study sites has been created in Portugal, Spain, France and Italy, where field manipulations alter the amount of water available to the ecosystem. The most up-to-date methods of ecophysiology, micrometeorology, soil ecology and remote sensing have been used to elucidate the mechanisms that regulate the response of vegetation and soil to changes in water availability. This information is providing the basis for the implementation and validation of simulation models capable of predicting the drought response of Mediterranean terrestrial ecosystems, and their vulnerability to future climate change, on a larger scale. The out-coming results are elucidating how water availability affects plant ecophysiological processes, the dynamics of soil carbon and the overall exchange of mass and energy between the land and the atmosphere. This paper focuses on some of the important, yet preliminary, results on C and energy fluxes that have been obtained at the large scale troughfall manipulation experiment (Tolfa, Italy, in a forest dominated by Arbutus unedo L.

  18. Ecosystem screening approach for pathogen-associated microorganisms affecting host disease.

    Science.gov (United States)

    Galiana, Eric; Marais, Antoine; Mura, Catherine; Industri, Benoît; Arbiol, Gilles; Ponchet, Michel

    2011-09-01

    The microbial community in which a pathogen evolves is fundamental to disease outcome. Species interacting with a pathogen on the host surface shape the distribution, density, and genetic diversity of the inoculum, but the role of these species is rarely determined. The screening method developed here can be used to characterize pathogen-associated species affecting disease. This strategy involves three steps: (i) constitution of the microbial community, using the pathogen as a trap; (ii) community selection, using extracts from the pathogen as the sole nutrient source; and (iii) molecular identification and the screening of isolates focusing on their effects on the growth of the pathogen in vitro and host disease. This approach was applied to a soilborne plant pathogen, Phytophthora parasitica, structured in a biofilm, for screening the microbial community from the rhizosphere of Nicotiana tabacum (the host). Two of the characterized eukaryotes interfered with the oomycete cycle and may affect the host disease. A Vorticella species acted through a mutualistic interaction with P. parasitica, disseminating pathogenic material by leaving the biofilm. A Phoma species established an amensal interaction with P. parasitica, strongly suppressing disease by inhibiting P. parasitica germination. This screening method is appropriate for all nonobligate pathogens. It allows the definition of microbial species as promoters or suppressors of a disease for a given biotope. It should also help to identify important microbial relationships for ecology and evolution of pathogens.

  19. Ecological impacts of atmospheric pollution and interactions with climate change in terrestrial ecosystems of the Mediterranean Basin: Current research and future directions

    International Nuclear Information System (INIS)

    Ochoa-Hueso, Raúl; Munzi, Silvana; Alonso, Rocío; Arróniz-Crespo, María; Avila, Anna; Bermejo, Victoria; Bobbink, Roland; Branquinho, Cristina; Concostrina-Zubiri, Laura; Cruz, Cristina; Cruz de Carvalho, Ricardo; De Marco, Alessandra; Dias, Teresa; Elustondo, David

    2017-01-01

    Mediterranean Basin ecosystems, their unique biodiversity, and the key services they provide are currently at risk due to air pollution and climate change, yet only a limited number of isolated and geographically-restricted studies have addressed this topic, often with contrasting results. Particularities of air pollution in this region include high O 3 levels due to high air temperatures and solar radiation, the stability of air masses, and dominance of dry over wet nitrogen deposition. Moreover, the unique abiotic and biotic factors (e.g., climate, vegetation type, relevance of Saharan dust inputs) modulating the response of Mediterranean ecosystems at various spatiotemporal scales make it difficult to understand, and thus predict, the consequences of human activities that cause air pollution in the Mediterranean Basin. Therefore, there is an urgent need to implement coordinated research and experimental platforms along with wider environmental monitoring networks in the region. In particular, a robust deposition monitoring network in conjunction with modelling estimates is crucial, possibly including a set of common biomonitors (ideally cryptogams, an important component of the Mediterranean vegetation), to help refine pollutant deposition maps. Additionally, increased attention must be paid to functional diversity measures in future air pollution and climate change studies to establish the necessary link between biodiversity and the provision of ecosystem services in Mediterranean ecosystems. Through a coordinated effort, the Mediterranean scientific community can fill the above-mentioned gaps and reach a greater understanding of the mechanisms underlying the combined effects of air pollution and climate change in the Mediterranean Basin. - Highlights: • Mediterranean Basin ecosystems are at risk due to air pollution and climate change. • A more robust monitoring network in conjunction with modelling estimates is crucial. • Monitoring networks should

  20. The importance of biological factors affecting trace metal concentration as revealed from accumulation patterns in co-occurring terrestrial invertebrates

    Energy Technology Data Exchange (ETDEWEB)

    Hendrickx, Frederik; Maelfait, Jean-Pierre; Bogaert, Nicolas; Tojal, Catarina; Du Laing, Gijs; Tack, Filip M.G.; Verloo, Marc G

    2004-02-01

    As physicochemical properties of the soil highly influence the bioavailable fraction of a particular trace metal, measured metal body burdens in a particular species are often assumed to be more reliable estimators of the contamination of the biota. To test this we compared the Cd, Cu and Zn content of three spiders (generalist predators) and two amphipods (detritivores), co-occurring in seven tidal marshes along the river Schelde, between each other and with the total metal concentrations and the concentrations of four sequential extractions of the soils. Correlations were significant in only one case and significant sitexspecies interactions for all metals demonstrate that factors affecting metal concentration were species and site specific and not solely determined by site specific characteristics. These results emphasize that site and species specific biological factors might be of the utmost importance in determining the contamination of the biota, at least for higher trophic levels. A hypothetical example clarifies these findings. - Site and species specific biological factors are important in determining contamination of biota.

  1. Life cycle stage and water depth affect flooding-induced adventitious root formation in the terrestrial species Solanum dulcamara.

    Science.gov (United States)

    Zhang, Qian; Visser, Eric J W; de Kroon, Hans; Huber, Heidrun

    2015-08-01

    Flooding can occur at any stage of the life cycle of a plant, but often adaptive responses of plants are only studied at a single developmental stage. It may be anticipated that juvenile plants may respond differently from mature plants, as the amount of stored resources may differ and morphological changes can be constrained. Moreover, different water depths may require different strategies to cope with the flooding stress, the expression of which may also depend on developmental stage. This study investigated whether flooding-induced adventitious root formation and plant growth were affected by flooding depth in Solanum dulcamara plants at different developmental stages. Juvenile plants without pre-formed adventitious root primordia and mature plants with primordia were subjected to shallow flooding or deep flooding for 5 weeks. Plant growth and the timing of adventitious root formation were monitored during the flooding treatments. Adventitious root formation in response to shallow flooding was significantly constrained in juvenile S. dulcamara plants compared with mature plants, and was delayed by deep flooding compared with shallow flooding. Complete submergence suppressed adventitious root formation until up to 2 weeks after shoots restored contact with the atmosphere. Independent of developmental stage, a strong positive correlation was found between adventitious root formation and total biomass accumulation during shallow flooding. The potential to deploy an escape strategy (i.e. adventitious root formation) may change throughout a plant's life cycle, and is largely dependent on flooding depth. Adaptive responses at a given stage of the life cycle thus do not necessarily predict how the plant responds to flooding in another growth stage. As variation in adventitious root formation also correlates with finally attained biomass, this variation may form the basis for variation in resistance to shallow flooding among plants. © The Author 2015. Published by

  2. African dust carries microbes across the ocean: are they affecting human and ecosystem health?

    Science.gov (United States)

    Kellogg, Christina A.; Griffin, Dale W.

    2003-01-01

    Atmospheric transport of dust from northwest Africa to the western Atlantic Ocean region may be responsible for a number of environmental hazards, including the demise of Caribbean corals; red tides; amphibian diseases; increased occurrence of asthma in humans; and oxygen depletion (eutrophication) in estuaries. Studies of satellite images suggest that hundreds of millions of tons of dust are trans-ported annually at relatively low altitudes across the Atlantic Ocean to the Caribbean Sea and southeastern United States. The dust emanates from the expanding Sahara/Sahel desert region in Africa and carries a wide variety of bacteria and fungi. The U.S. Geological Survey, in collaboration with the NASA/Goddard Spaceflight Center, is conducting a study to identify microbes--bacteria, fungi, viruses--transported across the Atlantic in African soil dust. Each year, millions of tons of desert dust blow off the west African coast and ride the trade winds across the ocean, affecting the entire Caribbean basin, as well as the southeastern United States. Of the dust reaching the U.S., Florida receives about 50 percent, while the rest may range as far north as Maine or as far west as Colorado. The dust storms can be tracked by satellite and take about one week to cross the Atlantic.

  3. Evaluating the potential of large-scale simulations to predict carbon fluxes of terrestrial ecosystems over a European Eddy Covariance network

    International Nuclear Information System (INIS)

    Balzarolo, M.; Boussetta, S.; Balsamo, G.; Beljaars, A.; Maignan, F.; Chevallier, F.; Poulter, B.

    2014-01-01

    This paper reports a comparison between large scale simulations of three different land surface models (LSMs), ORCHIDEE, ISBA-A-gs and CTESSEL, forced with the same meteorological data, and compared with the carbon fluxes measured at 32 eddy covariance (EC) flux tower sites in Europe. The results show that the three simulations have the best performance for forest sites and the poorest performance for cropland and grassland sites. In addition, the three simulations have difficulties capturing the seasonality of Mediterranean and sub-tropical biomes, characterized by dry summers. This reduced simulation performance is also reflected in deficiencies in diagnosed light-use efficiency (LUE) and vapour pressure deficit (VPD) dependencies compared to observations. Shortcomings in the forcing data may also play a role. These results indicate that more research is needed on the LUE and VPD functions for Mediterranean and sub-tropical biomes. Finally, this study highlights the importance of correctly representing phenology (i.e. leaf area evolution) and management (i.e. rotation-irrigation for cropland, and grazing-harvesting for grassland) to simulate the carbon dynamics of European ecosystems and the importance of ecosystem-level observations in model development and validation. (authors)

  4. Evaluating the effects of terrestrial ecosystems, climate and carbon dioxide on weathering over geological time: a global-scale process-based approach

    Science.gov (United States)

    Taylor, Lyla L.; Banwart, Steve A.; Valdes, Paul J.; Leake, Jonathan R.; Beerling, David J.

    2012-01-01

    Global weathering of calcium and magnesium silicate rocks provides the long-term sink for atmospheric carbon dioxide (CO2) on a timescale of millions of years by causing precipitation of calcium carbonates on the seafloor. Catchment-scale field studies consistently indicate that vegetation increases silicate rock weathering, but incorporating the effects of trees and fungal symbionts into geochemical carbon cycle models has relied upon simple empirical scaling functions. Here, we describe the development and application of a process-based approach to deriving quantitative estimates of weathering by plant roots, associated symbiotic mycorrhizal fungi and climate. Our approach accounts for the influence of terrestrial primary productivity via nutrient uptake on soil chemistry and mineral weathering, driven by simulations using a dynamic global vegetation model coupled to an ocean–atmosphere general circulation model of the Earth's climate. The strategy is successfully validated against observations of weathering in watersheds around the world, indicating that it may have some utility when extrapolated into the past. When applied to a suite of six global simulations from 215 to 50 Ma, we find significantly larger effects over the past 220 Myr relative to the present day. Vegetation and mycorrhizal fungi enhanced climate-driven weathering by a factor of up to 2. Overall, we demonstrate a more realistic process-based treatment of plant fungal–geosphere interactions at the global scale, which constitutes a first step towards developing ‘next-generation’ geochemical models. PMID:22232768

  5. Working group 4: Terrestrial

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    A working group at a Canada/USA symposium on climate change and the Arctic identified major concerns and issues related to terrestrial resources. The group examined the need for, and the means of, involving resource managers and users at local and territorial levels in the process of identifying and examining the impacts and consequences of climatic change. Climatic change will be important to the Arctic because of the magnitude of the change projected for northern latitudes; the apparent sensitivity of its terrestrial ecosystems, natural resources, and human support systems; and the dependence of the social, cultural, and economic welfare of Arctic communities, businesses, and industries on the health and quality of their environment. Impacts of climatic change on the physical, biological, and associated socio-economic environment are outlined. Gaps in knowledge needed to quantify these impacts are listed along with their relationships with resource management. Finally, potential actions for response and adaptation are presented

  6. Ecosystem-atmosphere interactions in the Arctic

    DEFF Research Database (Denmark)

    López-Blanco, Efrén

    The terrestrial CO2 exchange in the Arctic plays an important role in the global carbon (C) cycle. The Arctic ecosystems, containing a large amount of organic carbon (C), are experiencing on-going warming in recent decades, which is affecting the C cycling and the feedback interactions between its...... of measurement sites, particularly covering full annual cycles, but also the frequent gaps in data affected by extreme conditions and remoteness. Combining ecosystem models and field observations we are able to study the underlying processes of Arctic CO2 exchange in changing environments. The overall aim...... of the research is to use data-model approaches to analyse the patterns of C exchange and their links to biological processes in Arctic ecosystems, studied in detail both from a measurement and a modelling perspective, but also from a local to a pan-arctic scale. In Paper I we found a compensatory response...

  7. The effect of anthropogenic contaminations (PAH, PCB) on terrestrial annelids in conurban ecosystems. Final report; Einfluss von anthropogenen Schadstoffen (PAK und PCB) auf terrestrische Invertebraten urbaner Oekosysteme. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Achazi, R.K.; Beylich, A.; Chroszcz, G.; Dueker, C.; Heck, M.; Henneken, M.; Flenner, C.; Froehlich, E.; Garbers, U.; Khan, M.A.; Kreibich, M.; Kronshage, J.; Philippe, L.; Pilz, C.; Rothe, B.; Schabedoth, E.; Schaub, K.; Scheiwe, E.; Schmid, C.; Steudel, I.; Struwe, M.; Throl, C.; Wuertz, S. [Freie Univ. Berlin (Germany); Back, H.; Naehring, D.; Thielemann, U. [Gesellschaft fuer Angewandte Oekologie und Umweltplanung mbH, Nussloch (Germany)

    1997-09-23

    The project was conducted from August 1993 until May 1997. The objectives were (a) an elaboration of effect concentrations and index values for organic contaminants (PAH, PCB) and heavy metals in soil of conurbations for the community of decomposers, (b) the improvement of a biotest system for the evaluation of the habitat function of contaminated soils and (c) to obtain informations concerning a controlled utilization of contaminated areas. For that purpose field investigations in former sewage water irrigation areas of Berlin, Germany, concerning the abundance, species composition and dominance structure of terrestrial annelids (Enchytraeids, Lumbricids) were performed, as well as bioassays using contaminated soils of these sites and soils spiked with bezo(a)pyrene, fluoranthene, PCB 52, Cd and Cu and experiments on accumulation, elimination and biotransformation in annelids. 12 of the 17 sites investigated lacked earthworms, while only 2 sites lacked enchytraeids. The abundance of enchytraeids was in the range of 500 to 12.500/m{sup 2}, compared to 25.000 to 280.000/m{sup 2} on reference sites. The hostility of the soils of former irrigation fields to annelids was confirmed by lamina bait tests and by bioassays with Enchytraeus crypticus, E. albidus, E. buchholzi and Eisenia f. fetida. The ecotoxicity of the combined contaminants was enforced by the acidity and the degradation of the soils. The toxicity of organic and inorganic contaminants to terrestrial annelids was definitely proved by reproduction tests in the agar test system. The applied methods of investigation can be used for evaluation of contaminated soils. (orig.) [Deutsch] Das Projekt wurde von August 1993 bis Mai 1997 durchgefuehrt. Ziele waren die Erarbeitung (a) von Wirkschwellen fuer organische Schadstoffgruppen (PAK, PCB) und Schwermetalle im Boden fuer Destruenten urbaner Oekosysteme, (b) von Biotestsystemen zur Bewertung der Lebensraumfunktion belasteter Boeden und (c) von Hinweisen zur

  8. Unifying Dynamic Prognostic Phenology, Heterogeneous Soil and Vegetation Fluxes, and Ecosystem Biomass and Carbon Stocks To Predict the Terrestrial Carbon Cycle and Land-Atmosphere Exchanges in the Simple Biosphere Model (SiB4)

    Science.gov (United States)

    Haynes, K. D.; Baker, I. T.; Denning, S.

    2016-12-01

    Future climate projections require process-based models that incorporate the mechanisms and feedbacks controlling the carbon cycle. Over the past three decades, land surface models have been key contributors to Earth system models, evolving from predicting latent (LE) and sensible (SH) heat fluxes to energy and water budgets, momentum transfer, and terrestrial carbon exchange and storage. This study presents the latest version of the Simple Biosphere Model (SiB4), which builds on a compilation of previous versions and adds a new mechanistic-based scheme that fully predicts the terrestrial carbon cycle. The main SiB4 updates can be summarized as follows: (i) Incorporation of carbon pools that use new respiration and transfer methods, (ii) Creation of a new dynamic phenology scheme that uses mechanistic-based seasonal stages, and (iii) Unification of carbon pools, phenology and disturbance to close the carbon cycle. SiB4 removes the dependence on satellite-based vegetation indices, and instead uses a single mathematical framework to prognose self-consistent land-atmosphere exchanges of carbon, water, energy, radiation, and momentum, as well as carbon storage. Since grasslands cover 30% of land and are highly seasonal, we investigated forty grass sites. Diurnal cycles of gross primary productivity (GPP), ecosystem respiration (RE), net ecosystem exchange (NEE), LE and SH have third-quartile root mean squared (RMS) errors less than 2.0 µmol m-2 s-1, 1.9 µmol m-2 s-1, 2.0 µmol m-2 s-1, 42 W m-2, and 78 W m-2, respectively. On the synoptic timeframe, all sites have significant LE correlation coefficients of non-seasonal daily data; and all but one have significant SH correlations. Mean seasonal cycles for leaf area index (LAI), GPP, RE, LE, and SH have third-quartile normalized RMS errors less than 32%, 25%, 28%, 16%, and 48%, respectively. On multi-year timescales, daily correlations of LAI, GPP, RE, and LE are all statistically significant, with third-quartile RMS

  9. Arsenic species in ecosystems affected by arsenic-rich spring water near an abandoned mine in Korea

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Y.T. [Department of Earth System Science, Yonsei University, 134 Shinchon-Dong, Sudaemoon-Gu, Seoul 120-749 (Korea, Republic of); Nano Environment Materials Research Team, Korea Basic Science Institute, Seoul 136-600 (Korea, Republic of); Yoon, H.O., E-mail: dunee@kbsi.re.k [Nano Environment Materials Research Team, Korea Basic Science Institute, Seoul 136-600 (Korea, Republic of); Yoon, C. [Nano Environment Materials Research Team, Korea Basic Science Institute, Seoul 136-600 (Korea, Republic of); Woo, N.C., E-mail: ncwoo@yonsei.ac.k [Department of Earth System Science, Yonsei University, 134 Shinchon-Dong, Sudaemoon-Gu, Seoul 120-749 (Korea, Republic of)

    2009-12-15

    The objectives of this study were to quantitatively estimate the distribution of arsenic with its speciation and to identify potential pathways for transformation of arsenic species from samples of water, sediments, and plants in the ecosystem affected by the Cheongog Spring, where As(V) concentration reached levels up to 0.270 mg L{sup -1}. After flowing about 100 m downstream, the arsenic level showed a marked reduction to 0.044 mg L{sup -1} (about 84% removal) without noticeable changes in major water chemistry. The field study and laboratory hydroponic experiments with the dominant emergent plants along the creek (water dropwort and thunbergian smartweed) indicated that arsenic distribution, reduction, and speciation appear to be controlled by, (i) sorption onto stream sediments in exchangeable fractions, (ii) bioaccumulation by and possible release from emergent plants, and (iii) transformation of As(V) to As(III) and organic species through biological activities. - Biogeochemical reactions with emergent plants and sediments control the fate of arsenic along creeks originating from a high-As Spring.

  10. Reconciling estimates of the contemporary North American carbon balance among terrestrial biosphere models, atmospheric inversions, and a new approach for estimating net ecosystem exchange from inventory-based data

    Science.gov (United States)

    Hayes, Daniel J.; Turner, David P.; Stinson, Graham; McGuire, A. David; Wei, Yaxing; West, Tristram O.; Heath, Linda S.; de Jong, Bernardus; McConkey, Brian G.; Birdsey, Richard A.; Kurz, Werner A.; Jacobson, Andrew R.; Huntzinger, Deborah N.; Pan, Yude; Post, W. Mac; Cook, Robert B.

    2012-01-01

    We develop an approach for estimating net ecosystem exchange (NEE) using inventory-based information over North America (NA) for a recent 7-year period (ca. 2000–2006). The approach notably retains information on the spatial distribution of NEE, or the vertical exchange between land and atmosphere of all non-fossil fuel sources and sinks of CO2, while accounting for lateral transfers of forest and crop products as well as their eventual emissions. The total NEE estimate of a -327 ± 252 TgC yr-1 sink for NA was driven primarily by CO2 uptake in the Forest Lands sector (-248 TgC yr-1), largely in the Northwest and Southeast regions of the US, and in the Crop Lands sector (-297 TgC yr-1), predominantly in the Midwest US states. These sinks are counteracted by the carbon source estimated for the Other Lands sector (+218 TgC yr-1), where much of the forest and crop products are assumed to be returned to the atmosphere (through livestock and human consumption). The ecosystems of Mexico are estimated to be a small net source (+18 TgC yr-1) due to land use change between 1993 and 2002. We compare these inventory-based estimates with results from a suite of terrestrial biosphere and atmospheric inversion models, where the mean continental-scale NEE estimate for each ensemble is -511 TgC yr-1 and -931 TgC yr-1, respectively. In the modeling approaches, all sectors, including Other Lands, were generally estimated to be a carbon sink, driven in part by assumed CO2 fertilization and/or lack of consideration of carbon sources from disturbances and product emissions. Additional fluxes not measured by the inventories, although highly uncertain, could add an additional -239 TgC yr-1 to the inventory-based NA sink estimate, thus suggesting some convergence with the modeling approaches.

  11. Terrestrial Analogs to Mars

    Science.gov (United States)

    Farr, T. G.; Arcone, S.; Arvidson, R. W.; Baker, V.; Barlow, N. G.; Beaty, D.; Bell, M. S.; Blankenship, D. D.; Bridges, N.; Briggs, G.; Bulmer, M.; Carsey, F.; Clifford, S. M.; Craddock, R. A.; Dickerson, P. W.; Duxbury, N.; Galford, G. L.; Garvin, J.; Grant, J.; Green, J. R.; Gregg, T. K. P.; Guinness, E.; Hansen, V. L.; Hecht, M. H.; Holt, J.; Howard, A.; Keszthelyi, L. P.; Lee, P.; Lanagan, P. D.; Lentz, R. C. F.; Leverington, D. W.; Marinangeli, L.; Moersch, J. E.; Morris-Smith, P. A.; Mouginis-Mark, P.; Olhoeft, G. R.; Ori, G. G.; Paillou, P.; Reilly, J. F., II; Rice, J. W., Jr.; Robinson, C. A.; Sheridan, M.; Snook, K.; Thomson, B. J.; Watson, K.; Williams, K.; Yoshikawa, K.

    2002-08-01

    It is well recognized that interpretations of Mars must begin with the Earth as a reference. The most successful comparisons have focused on understanding geologic processes on the Earth well enough to extrapolate to Mars' environment. Several facets of terrestrial analog studies have been pursued and are continuing. These studies include field workshops, characterization of terrestrial analog sites, instrument tests, laboratory measurements (including analysis of Martian meteorites), and computer and laboratory modeling. The combination of all these activities allows scientists to constrain the processes operating in specific terrestrial environments and extrapolate how similar processes could affect Mars. The Terrestrial Analogs for Mars Community Panel has considered the following two key questions: (1) How do terrestrial analog studies tie in to the Mars Exploration Payload Assessment Group science questions about life, past climate, and geologic evolution of Mars, and (2) How can future instrumentation be used to address these questions. The panel has considered the issues of data collection, value of field workshops, data archiving, laboratory measurements and modeling, human exploration issues, association with other areas of solar system exploration, and education and public outreach activities.

  12. MODIS-derived terrestrial primary production [chapter 28

    Science.gov (United States)

    Maosheng Zhao; Steven Running; Faith Ann Heinsch; Ramakrishna Nemani

    2011-01-01

    Temporal and spatial changes in terrestrial biological productivity have a large impact on humankind because terrestrial ecosystems not only create environments suitable for human habitation, but also provide materials essential for survival, such as food, fiber and fuel. A recent study estimated that consumption of terrestrial net primary production (NPP; a list of...

  13. Marine and terrestrial factors affecting Adélie penguin Pygoscelis adeliae chick growth and recruitment off the western Antarctic Peninsula

    Science.gov (United States)

    Chapman, Erik W.; Hofmann, Eileen E.; Patterson, Donna L.; Ribic, Christine A.; Fraser, William R.

    2011-01-01

    An individual-based bioenergetics model that simulates the growth of an Adélie penguin Pygoscelis adeliaechick from hatching to fledging was used to assess marine and terrestrial factors that affect chick growth and fledging mass off the western Antarctic Peninsula. Simulations considered the effects on Adélie penguin fledging mass of (1) modification of chick diet through the addition of Antarctic silverfish Pleuragramma antarcticum to an all-Antarctic krillEuphausia superba diet, (2) reduction of provisioning rate which may occur as a result of an environmental stress such as reduced prey availability, and (3) increased thermoregulatory costs due to wetting of chicks which may result from increased precipitation or snow-melt in colonies. Addition of 17% Antarctic silverfish of Age-Class 3 yr (AC3) to a penguin chick diet composed of Antarctic krill increased chick fledging mass by 5%. Environmental stress that results in >4% reduction in provisioning rate or wetting of just 10% of the chick’s surface area decreased fledging mass enough to reduce the chick’s probability of successful recruitment. The negative effects of reduced provisioning and wetting on chick growth can be compensated for by inclusion of Antarctic silverfish of AC3 and older in the chick diet. Results provide insight into climate-driven processes that influence chick growth and highlight a need for field research designed to investigate factors that determine the availability of AC3 and older Antarctic silverfish to foraging Adélie penguins and the influence of snowfall on chick wetting, thermoregulation and adult provisioning rate.

  14. Equilibration of the terrestrial water, nitrogen, and carbon cycles

    OpenAIRE

    Schimel, David S.; Braswell, B. H.; Parton, W. J.

    1997-01-01

    Recent advances in biologically based ecosystem models of the coupled terrestrial, hydrological, carbon, and nutrient cycles have provided new perspectives on the terrestrial biosphere’s behavior globally, over a range of time scales. We used the terrestrial ecosystem model Century to examine relationships between carbon, nitrogen, and water dynamics. The model, run to a quasi-steady-state, shows strong correlations between carbon, water, and nitrogen fluxes that l...

  15. Terrestrial magnetosphere

    International Nuclear Information System (INIS)

    Pande, D.C.; Agarwal, D.C.

    1982-01-01

    This paper presents a review about terrestrial magnetosphere. During the last few years considerable investigation have been carried out about the properties of Solar Wind and its interaction with planetary magnetic fields. It is therefore of high importance to accumulate all the investigations in a comprehensive form. The paper reviews the property of earth's magnetosphere, magnetosheath, magneto pause, polar cusps, bow shook and plasma sheath. (author)

  16. Potential increases in natural disturbance rates could offset forest management impacts on ecosystem carbon stocks.

    Science.gov (United States)

    John B. Bradford; Nicholas R. Jensen; Grant M. Domke; Anthony W. D' Amato

    2013-01-01

    Forested ecosystems contain the majority of the world’s terrestrial carbon, and forest management has implications for regional and global carbon cycling. Carbon stored in forests changes with stand age and is affected by natural disturbance and timber harvesting. We examined how harvesting and disturbance interact to influence forest carbon stocks over the Superior...

  17. Soil and terrestrial biology studies

    International Nuclear Information System (INIS)

    Anon.

    1976-01-01

    Soil and terrestrial biology studies focused on developing an understanding of the uptake of gaseous substances from the atmosphere by plants, biodegradation of oil, and the movement of Pu in the terrestrial ecosystems of the southeastern United States. Mathematical models were developed for SO 2 and tritium uptake from the atmosphere by plants; the uptake of tritium by soil microorganisms was measured; and the relationships among the Pu content of soil, plants, and animals of the Savannah River Plant area were studied. Preliminary results are reported for studies on the biodegradation of waste oil on soil surfaces

  18. Seasonality and Management Affect Land Surface Temperature Differences Between Loblolly Pine and Switchgrass Ecosystems in Central Virginia

    Science.gov (United States)

    Ahlswede, B.; Thomas, R. Q.; O'Halloran, T. L.; Rady, J.; LeMoine, J.

    2017-12-01

    Changes in land-use and land management can have biogeochemical and biophysical effects on local and global climate. While managed ecosystems provide known food and fiber benefits, their influence on climate is less well quantified. In the southeastern United States, there are numerous types of intensely managed ecosystems but pine plantations and switchgrass fields represent two biogeochemical and biophysical extremes; a tall, low albedo forest with trees harvested after multiple decades vs. a short, higher albedo C4 grass field that is harvested annually. Despite the wide spread use of these ecosystems for timber and bioenergy, a quantitative, empirical evaluation of the net influence of these ecosystems on climate is lacking because it requires measuring both the greenhouse gas and energy balance of the ecosystems while controlling for the background weather and soil environment. To address this need, we established a pair of eddy flux towers in these ecosystems that are co-located (1.5 km apart) in Central Virginia and measured the radiative energy, non-radiative energy and carbon fluxes, along with associated biometeorology variables; the paired site has run since April 2016. During the first 1.5 years (two growing seasons), we found strong seasonality in the difference in surface temperature between the two ecosystems. In the growing seasons, both sites had similar surface temperature despite higher net radiation in pine. Following harvest of the switchgrass in September, the switchgrass temperatures increased relative to pine. In the winter, the pine ecosystem was warmer. We evaluate the drivers of these intra-annual dynamics and compare the climate influence of these biophysical differences to the differences in carbon fluxes between the sites using a suite of established climate regulation services metrics. Overall, our results show tradeoffs exist between the biogeochemical and biophysical climate services in managed ecosystems in the southeastern United

  19. Conservación de la biodiversidad en Chile: Nuevos desafíos y oportunidades en ecosistemas terrestres y marinos costeros Biodiversity conservation in Chile: New challenges and opportunities in terrestrial and marine coastal ecosystems

    Directory of Open Access Journals (Sweden)

    CARMEN JORQUERA-JARAMILLO

    2012-09-01

    Full Text Available La pérdida de la biodiversidad producida por el crecimiento demográfico, la demanda por recursos y la actividad productiva es contradictoria con el reconocimiento de su importancia. En ecosistemas terrestres, el Sistema Nacional de Áreas Protegidas del Estado (SNASPE contiene cerca del 19 % del territorio de Chile continental; aunque no representa todos los ecosistemas con especies amenazadas, puede ser complementado implementando nuevas áreas protegidas públicas (AP y privadas (APP. El desarrollo de áreas marinas protegidas (AMP es incipiente, y algunas iniciativas comparten la responsabilidad de conservación con los usuarios locales. En Chile, un conjunto de reglamentos, normas legales y tratados internacionales promueven distintas oportunidades de conservación en ecosistemas terrestres y marinos costeros, de las cuales emergen nuevos desafíos. Entre estos destacan, estandarizar la clasificación de especies según categorías de conservación en un protocolo internacional y optimizar las metodologías para seleccionar áreas prioritarias, ambos criterios indispensables para decidir qué y dónde conservar. Otro desafío es integrar el valor intrínseco de la biodiversidad con los servicios ecosistémicos que presta para instaurar una cultura participativa. Esto mejoraría la efectividad de las distintas estrategias de protección y uso sustentable de la biodiversidad al incorporar la educación y la participación ciudadana desde una perspectiva biocultural. La educación fomenta la conservación de la naturaleza al hacernos conscientes de nuestro entorno; mientras que la participación involucra a los ciudadanos como un actor más en la toma de decisiones, procurando la aplicación efectiva de las estrategias de conservación de la biodiversidad.Biodiversity loss caused by population growth, the demand of resources and productive activities is inconsistent with the recognition of its importance. In terrestrial ecosystems, the

  20. Terrestrial Steering Group. 2014. Arctic Terrestrial Biodiversity Monitoring Plan

    DEFF Research Database (Denmark)

    Aastrup, Peter; Aronsson, Mora; Barry, Tom

    capacity and information may be currently available and (b) to outline near-term required steps to begin implementing the plan and reporting on an initial set of Arctic terrestrial biodiversity focal ecosystem component attributes. The specific objectives of the workshop were to: Identify key products...... for TSG for the next two years. Identify key components of a pan-Arctic status report for priority focal ecosystem components (FEC) attributes for policy and decision makers. Develop a prioritized set of activities to meet reporting objectives. Identify key milestones and timelines for the successful...... implementation of the Arctic Terrestrial Biodiversity Monitoring Plan for the next two years. Identify expert networks required for successful implementation of the plan. Identify key gaps and opportunities for the TSG related to plan implementation and identify near-term next steps to address gaps....

  1. Depletion of Serotonin Selectively Impairs Short-Term Memory without Affecting Long-Term Memory in Odor Learning in the Terrestrial Slug "Limax Valentianus"

    Science.gov (United States)

    Santa, Tomofumi; Kirino, Yutaka; Watanabe, Satoshi; Shirahata, Takaaki; Tsunoda, Makoto

    2006-01-01

    The terrestrial slug "Limax" is able to acquire short-term and long-term memories during aversive odor-taste associative learning. We investigated the effect of the selective serotonergic neurotoxin 5,7-dihydroxytryptamine (5,7-DHT) on memory. Behavioral studies indicated that 5,7-DHT impaired short-term memory but not long-term memory. HPLC…

  2. Future directions of ecosystem science

    Science.gov (United States)

    Baron, Jill S.; Galvin, Kathleen A.

    1990-01-01

    Scientific knowledge about ecosystem structure and function has expanded greatly during the past few decades. Terrestrial and aquatic nutrient cycling, ecosystem energetics, population dynamics, belowground processes, and food webs have been studied at the plot, stand, watershed, and landscape levels at many locations around the globe. Ideas about terrestrial-atmospheric interactions and human interference in these processes have changed dramatically. There is new appreciation of the need to incorporate into ecosystem studies the interactions between human populations and the ecosystem, not only because humans affect ecosystem processes, but because these systems support human populations (Glantz 1988, Holden 1988, Parry et al. 1988, WCED 1987). Recent advances in ecosystem science are due, in part, to technological improvements in computing power, new laboratory and field physical and chemical analytical techniques, and satellite imagery for remote sensing of Earth's structure and dynamics. Modeling and geographic information systems have provided the capability for integrating multiple data sets with process simulations to generate hypotheses about regional ecosystem function. Concurrent with these scientific developments has been a growing concern about the links between the health of the environment and world-wide industrial, land, and resource-management practices. Environmental damage at the local level was widely recognized in the 1960s, prompting the environmental movement of that decade. Regional environmental problems with multiple effects and politically difficult solutions have been perceived more recently; the issue of acidic deposition provides an example of such a second-generation concern (Clark and Holling 1985). Today there is a growing awareness of global-scale environmental degradation brought about by the combined actions of all peoples on Earth (Clark 1989, Woodmansee et al. 1988). The three levels of environmental concern--local, regional

  3. Hydraulic redistribution of soil water by roots affects whole-stand evapotranspiration and net ecosystem carbon exchange

    Science.gov (United States)

    J.-C. Domec; J.S. King; A. Noormets; E. Treasure; M.J. Gavazzi; G. Sun; S.G. McNulty

    2010-01-01

    Hydraulic redistribution (HR) of water via roots from moist to drier portions of the soil occurs in many ecosystems, potentially influencing both water use and carbon assimilation. By measuring soil water content, sap flow and eddy covariance, we investigated the temporal variability of HR in a loblolly pine (Pinus taeda) plantation during months of...

  4. Do differences in food web structure between organic and conventional farms affect the ecosystem service of pest control?

    NARCIS (Netherlands)

    Macfadyen, S.; Gibson, R.; Polaszek, A.; Morris, R.J.; Craze, P.G.; Planque, R.; Symondson, W.O.C.; Memmott, J.

    2009-01-01

    While many studies have demonstrated that organic farms support greater levels of biodiversity, it is not known whether this translates into better provision of ecosystem services. Here we use a food-web approach to analyse the community structure and function at the whole-farm scale. Quantitative

  5. Are rocky shore ecosystems affected by nutrient-enriched seawater? Some preliminary results from a mesocosm experiment

    NARCIS (Netherlands)

    Bokn, T.L.; Moy, F.E.; Christie, H.; Engelbert, S.; Karez, R.; Kersting, K.; Kraufvelin, P.; Lindblad, C.; Marba, N.; Pedersen, M.F.; Sorensen, K.

    2002-01-01

    The response of rocky shore ecosystems to increased nutrient availability was examined in eight land-based mesocosms designed for hard-bottom littoral communities built at Marine Research Station Solbergstrand (Norway). The average seawater volume in each basin was 9 m3 with an average water

  6. Environmental risk assessment for invasive alien species : A case study of apple snails affecting ecosystem services in Europe

    NARCIS (Netherlands)

    Gilioli, Gianni; Schrader, Gritta; Carlsson, Nils; van Donk, Ellen; van Leeuwen, Casper H.A.; Martín, Pablo R.; Pasquali, Sara; Vilà, Montserrat; Vos, Sybren

    2017-01-01

    The assessment of the risk posed by invasive alien species (IAS) to the environment is a component of increasing importance for Pest Risk Analysis. Standardized and comprehensive procedures to assess their impacts on ecosystem services have been developed only recently. The invasive apple snails

  7. Environmental risk assessment for invasive alien species: A case study of apple snails affecting ecosystem services in Europe

    NARCIS (Netherlands)

    Gilioli, Gianni; Schrader, Gritta; Carlsson, Nils; van Donk, Ellen; van Leeuwen, Casper H.A.; Martín, Pablo R.; Pasquali, Sara; Vilà, Montserrat; Vos, Sybren

    Abstract The assessment of the risk posed by invasive alien species (IAS) to the environment is a component of increasing importance for Pest Risk Analysis. Standardized and comprehensive procedures to assess their impacts on ecosystem services have been developed only recently. The invasive apple

  8. Mercury exposure in terrestrial birds far downstream of an historical point source

    International Nuclear Information System (INIS)

    Jackson, Allyson K.; Evers, David C.; Folsom, Sarah B.; Condon, Anne M.; Diener, John; Goodrick, Lizzie F.; McGann, Andrew J.; Schmerfeld, John; Cristol, Daniel A.

    2011-01-01

    Mercury (Hg) is a persistent environmental contaminant found in many freshwater and marine ecosystems. Historical Hg contamination in rivers can impact the surrounding terrestrial ecosystem, but there is little known about how far downstream this contamination persists. In 2009, we sampled terrestrial forest songbirds at five floodplain sites up to 137 km downstream of an historical source of Hg along the South and South Fork Shenandoah Rivers (Virginia, USA). We found that blood total Hg concentrations remained elevated over the entire sampling area and there was little evidence of decline with distance. While it is well known that Hg is a pervasive and long-lasting aquatic contaminant, it has only been recently recognized that it also biomagnifies effectively in floodplain forest food webs. This study extends the area of concern for terrestrial habitats near contaminated rivers for more than 100 km downstream from a waterborne Hg point source. - Highlights: → We report blood mercury levels for terrestrial songbirds downstream of contamination. → Blood mercury levels remain elevated above reference for at least 137 km downstream. → Trends vary based on foraging guild and migration strategy. → Mercury affects terrestrial biota farther downstream than previously documented. - Blood mercury levels of forest songbirds remain elevated above reference levels for at least 137 km downstream of historical point source.

  9. Mercury exposure in terrestrial birds far downstream of an historical point source

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, Allyson K., E-mail: allyson.jackson@briloon.org [Biodiversity Research Institute, 19 Flaggy Meadow Road, Gorham, ME 04038 (United States); Institute for Integrative Bird Behavior Studies, Department of Biology, College of William and Mary, PO Box 8795, Williamsburg, VA 23187 (United States); Evers, David C.; Folsom, Sarah B. [Biodiversity Research Institute, 19 Flaggy Meadow Road, Gorham, ME 04038 (United States); Condon, Anne M. [U.S. Fish and Wildlife Service, 6669 Short Lane, Gloucester, VA 23061 (United States); Diener, John; Goodrick, Lizzie F. [Biodiversity Research Institute, 19 Flaggy Meadow Road, Gorham, ME 04038 (United States); McGann, Andrew J. [Institute for Integrative Bird Behavior Studies, Department of Biology, College of William and Mary, PO Box 8795, Williamsburg, VA 23187 (United States); Schmerfeld, John [U.S. Fish and Wildlife Service, 6669 Short Lane, Gloucester, VA 23061 (United States); Cristol, Daniel A. [Institute for Integrative Bird Behavior Studies, Department of Biology, College of William and Mary, PO Box 8795, Williamsburg, VA 23187 (United States)

    2011-12-15

    Mercury (Hg) is a persistent environmental contaminant found in many freshwater and marine ecosystems. Historical Hg contamination in rivers can impact the surrounding terrestrial ecosystem, but there is little known about how far downstream this contamination persists. In 2009, we sampled terrestrial forest songbirds at five floodplain sites up to 137 km downstream of an historical source of Hg along the South and South Fork Shenandoah Rivers (Virginia, USA). We found that blood total Hg concentrations remained elevated over the entire sampling area and there was little evidence of decline with distance. While it is well known that Hg is a pervasive and long-lasting aquatic contaminant, it has only been recently recognized that it also biomagnifies effectively in floodplain forest food webs. This study extends the area of concern for terrestrial habitats near contaminated rivers for more than 100 km downstream from a waterborne Hg point source. - Highlights: > We report blood mercury levels for terrestrial songbirds downstream of contamination. > Blood mercury levels remain elevated above reference for at least 137 km downstream. > Trends vary based on foraging guild and migration strategy. > Mercury affects terrestrial biota farther downstream than previously documented. - Blood mercury levels of forest songbirds remain elevated above reference levels for at least 137 km downstream of historical point source.

  10. Variations and trends of terrestrial NPP and its relation to climate ...

    Indian Academy of Sciences (India)

    Using global terrestrial ecosystem net primary productivity (NPP) data, we validated the simulated multi-model ensemble ..... tion on the solar radiation at six Canadian stations; Solar ... balance have enhanced the terrestrial carbon sink in the.

  11. Forest ecosystem services affected by natural disturbances, climate and land-use changes in the Tatra Mountains

    Czech Academy of Sciences Publication Activity Database

    Fleischer, P.; Pichler, V.; Holko, L.; Fleischer Jr., P.; Máliš, F.; Gömöryová, E.; Cudlín, Pavel; Holeksa, J.; Michalová, Z.; Homolová, Z.; Škvarenina, J.; Střelcová, K.; Hlaváč, P.

    2017-01-01

    Roč. 73, 1-2 (2017), s. 57-71 ISSN 0936-577X R&D Projects: GA MŠk(CZ) LO1415 Institutional support: RVO:67179843 Keywords : Forest ecosystem state * Bark beetle outbreak * Long-term research Subject RIV: EH - Ecology, Behaviour OBOR OECD: Environmental sciences (social aspects to be 5.7) Impact factor: 1.578, year: 2016

  12. Forest type effects on the retention of radiocesium in organic layers of forest ecosystems affected by the Fukushima nuclear accident

    Science.gov (United States)

    Koarashi, Jun; Atarashi-Andoh, Mariko; Matsunaga, Takeshi; Sanada, Yukihisa

    2016-12-01

    The Fukushima Daiichi nuclear power plant disaster caused serious radiocesium (137Cs) contamination of forest ecosystems over a wide area. Forest-floor organic layers play a key role in controlling the overall bioavailability of 137Cs in forest ecosystems; however, there is still an insufficient understanding of how forest types influence the retention capability of 137Cs in organic layers in Japanese forest ecosystems. Here we conducted plot-scale investigations on the retention of 137Cs in organic layers at two contrasting forest sites in Fukushima. In a deciduous broad-leaved forest, approximately 80% of the deposited 137Cs migrated to mineral soil located below the organic layers within two years after the accident, with an ecological half-life of approximately one year. Conversely, in an evergreen coniferous forest, more than half of the deposited 137Cs remained in the organic layers, with an ecological half-life of 2.1 years. The observed retention behavior can be well explained by the tree phenology and accumulation of 137Cs associated with litter materials with different degrees of degradation in the organic layers. Spatial and temporal patterns of gamma-ray dose rates depended on the retention capability. Our results demonstrate that enhanced radiation risks last longer in evergreen coniferous forests than in deciduous broad-leaved forests.

  13. Central Hardwoods ecosystem vulnerability assessment and synthesis: a report from the Central Hardwoods Climate Change Response Framework project

    Science.gov (United States)

    Leslie Brandt; Hong He; Louis Iverson; Frank R. Thompson; Patricia Butler; Stephen Handler; Maria Janowiak; P. Danielle Shannon; Chris Swanston; Matthew Albrecht; Richard Blume-Weaver; Paul Deizman; John DePuy; William D. Dijak; Gary Dinkel; Songlin Fei; D. Todd Jones-Farrand; Michael Leahy; Stephen Matthews; Paul Nelson; Brad Oberle; Judi Perez; Matthew Peters; Anantha Prasad; Jeffrey E. Schneiderman; John Shuey; Adam B. Smith; Charles Studyvin; John M. Tirpak; Jeffery W. Walk; Wen J. Wang; Laura Watts; Dale Weigel; Steve. Westin

    2014-01-01

    The forests in the Central Hardwoods Region will be affected directly and indirectly by a changing climate over the next 100 years. This assessment evaluates the vulnerability of terrestrial ecosystems in the Central Hardwoods Region of Illinois, Indiana, and Missouri to a range of future climates. Information on current forest conditions, observed climate trends,...

  14. Effects of chemicals on terrestrial ecosystems exhibiting different types of stability. Pt. 2. Application of fractal geometry to structural analysis in terrestrial ecotoxicology; Auswirkungen von Chemikalien auf terrestrische Oekosysteme unterschiedlichen Stabilitaetstyps. T. 2. Anwendung der fraktalen Geometrie zur Strukturanalyse in der terrestrischen Oekotoxikologie

    Energy Technology Data Exchange (ETDEWEB)

    Bornkamm, R.; Darius, F.

    1995-04-01

    The problem at issue in the present study was whether and how reactions of terrestial ecosystems to anthropogenic xenobiotics can be measured and interpreted. For this pupose test were performed on two types of vegetation which are primarily distinguishable by their reproductive strategies (via seeds and buds, respectively) and also represented by plants of different taxonomic classes. The chemicals used were two low-dosed herbicides (2.4.5-T and atrazine) which elicit responses on several important physiological levels of the plant organism. Strength and duration of responses differed considerably between the two plant systems studied. These observations gave rise to the question as to what can be said on the tested plant systems in general concerning the extent and reversibility of the effects brought about by these interventions. For this purpose the processes assumed to be acting within the biocoeonoces had to be formulated in a model and interpreted. The resultant model permits following the chain of events leading from an individual stress reaction to a complex response of the whole system. It was possible to compare various simulation results with the reactions found in tests on real ecosystems and in other cases to derive from the hypotheses capable of experimental verification. The authors believe that activities in terrestrial ecotoxicology should go beyond the gathering of data from empirical substance testing, which is undoubtedly a necessity for licensing procedures, by furthering basic research. Theoretical considerations make it seem unrealistic to attempt predictions on the future development of any certain ecosystem (whether with or without anthropogenic stress). Statements on the probability of effects, by contrast, to have a certain validty, provided they are based on a sufficient knowledge of type-specific responses of systems and of influences of background conditions. (orig.) [Deutsch] Fuer die Bearbeitung des Problems, ob und wie Reaktionen

  15. The Circumpolar Biodiversity Monitoring Program Terrestrial Plan

    DEFF Research Database (Denmark)

    Christensen, Tom; Payne, J.; Doyle, M.

    , understand and report on long-term change in Arctic terrestrial ecosystems and biodiversity, and to identify knowledge gaps and priorities. This poster will outline the key management questions the plan aims to address and the proposed nested, multi-scaled approach linking targeted, research based monitoring...... and coastal environments. The CBMP Terrestrial Plan is a framework to focus and coordinate monitoring of terrestrial biodiversity across the Arctic. The goal of the plan is to improve the collective ability of Arctic traditional knowledge (TK) holders, northern communities, and scientists to detect...

  16. Termites create spatial structure and govern ecosystem function by affecting N2 fixation in an East African savanna.

    Science.gov (United States)

    Fox-Dobbs, Kena; Doak, Daniel F; Brody, Alison K; Palmer, Todd M

    2010-05-01

    The mechanisms by which even the clearest of keystone or dominant species exert community-wide effects are only partially understood in most ecosystems. This is especially true when a species or guild influences community-wide interactions via changes in the abiotic landscape. Using stable isotope analyses, we show that subterranean termites in an East African savanna strongly influence a key ecosystem process: atmospheric nitrogen fixation by a monodominant tree species and its bacterial symbionts. Specifically, we applied the 15N natural abundance method in combination with other biogeochemical analyses to assess levels of nitrogen fixation by Acacia drepanolobium and its effects on co-occurring grasses and forbs in areas near and far from mounds and where ungulates were or were not excluded. We find that termites exert far stronger effects than do herbivores on nitrogen fixation. The percentage of nitrogen derived from fixation in Acacia drepanolobium trees is higher (55-80%) away from mounds vs. near mounds (40-50%). Mound soils have higher levels of plant available nitrogen, and Acacia drepanolobium may preferentially utilize soil-based nitrogen sources in lieu of fixed nitrogen when these sources are readily available near termite mounds. At the scale of the landscape, our models predict that termite/soil derived nitrogen sources influence >50% of the Acacia drepanolobium trees in our system. Further, the spatial extent of these effects combine with the spacing of termite mounds to create highly regular patterning in nitrogen fixation rates, resulting in marked habitat heterogeneity in an otherwise uniform landscape. In summary, we show that termite-associated effects on nitrogen processes are not only stronger than those of more apparent large herbivores in the same system, but also occur in a highly regular spatial pattern, potentially adding to their importance as drivers of community and ecosystem structure.

  17. The sensitivity of terrestrial carbon storage to historical climate variability and atmospheric CO2 in the United States

    Science.gov (United States)

    Tian, H.; Melillo, J. M.; Kicklighter, D. W.; McGuire, A. D.; Helfrich, J.

    1999-04-01

    We use the Terrestrial Ecosystem Model (TEM, Version 4.1) and the land cover data set of the international geosphere biosphere program to investigate how increasing atmospheric CO2 concentration and climate variability during 1900 1994 affect the carbon storage of terrestrial ecosystems in the conterminous USA, and how carbon storage has been affected by land-use change. The estimates of TEM indicate that over the past 95years a combination of increasing atmospheric CO2 with historical temperature and precipitation variability causes a 4.2% (4.3Pg C) decrease in total carbon storage of potential vegetation in the conterminous US, with vegetation carbon decreasing by 7.2% (3.2Pg C) and soil organic carbon decreasing by 1.9% (1.1Pg C). Several dry periods including the 1930s and 1950s are responsible for the loss of carbon storage. Our factorial experiments indicate that precipitation variability alone decreases total carbon storage by 9.5%. Temperature variability alone does not significantly affect carbon storage. The effect of CO2 fertilization alone increases total carbon storage by 4.4%. The effects of increasing atmospheric CO2 and climate variability are not additive. Interactions among CO2, temperature and precipitation increase total carbon storage by 1.1%. Our study also shows substantial year-to-year variations in net carbon exchange between the atmosphere and terrestrial ecosystems due to climate variability. Since the 1960s, we estimate these terrestrial ecosystems have acted primarily as a sink of atmospheric CO2 as a result of wetter weather and higher atmospheric CO2 concentrations. For the 1980s, we estimate the natural terrestrial ecosystems, excluding cropland and urban areas, of the conterminous US have accumulated 78.2 Tg C yr1 because of the combined effect of increasing atmospheric CO2 and climate variability. For the conterminous US, we estimate that the conversion of natural ecosystems to cropland and urban areas has caused a 18.2% (17.7Pg C

  18. How will ocean acidification affect Baltic sea ecosystems? an assessment of plausible impacts on key functional groups.

    Science.gov (United States)

    Havenhand, Jonathan N

    2012-09-01

    Increasing partial pressure of atmospheric CO₂ is causing ocean pH to fall-a process known as 'ocean acidification'. Scenario modeling suggests that ocean acidification in the Baltic Sea may cause a ≤ 3 times increase in acidity (reduction of 0.2-0.4 pH units) by the year 2100. The responses of most Baltic Sea organisms to ocean acidification are poorly understood. Available data suggest that most species and ecologically important groups in the Baltic Sea food web (phytoplankton, zooplankton, macrozoobenthos, cod and sprat) will be robust to the expected changes in pH. These conclusions come from (mostly) single-species and single-factor studies. Determining the emergent effects of ocean acidification on the ecosystem from such studies is problematic, yet very few studies have used multiple stressors and/or multiple trophic levels. There is an urgent need for more data from Baltic Sea populations, particularly from environmentally diverse regions and from controlled mesocosm experiments. In the absence of such information it is difficult to envision the likely effects of future ocean acidification on Baltic Sea species and ecosystems.

  19. Do differences in food web structure between organic and conventional farms affect the ecosystem service of pest control?

    Science.gov (United States)

    Macfadyen, Sarina; Gibson, Rachel; Polaszek, Andrew; Morris, Rebecca J; Craze, Paul G; Planqué, Robert; Symondson, William O C; Memmott, Jane

    2009-03-01

    While many studies have demonstrated that organic farms support greater levels of biodiversity, it is not known whether this translates into better provision of ecosystem services. Here we use a food-web approach to analyse the community structure and function at the whole-farm scale. Quantitative food webs from 10 replicate pairs of organic and conventional farms showed that organic farms have significantly more species at three trophic levels (plant, herbivore and parasitoid) and significantly different network structure. Herbivores on organic farms were attacked by more parasitoid species on organic farms than on conventional farms. However, differences in network structure did not translate into differences in robustness to simulated species loss and we found no difference in percentage parasitism (natural pest control) across a variety of host species. Furthermore, a manipulative field experiment demonstrated that the higher species richness of parasitoids on the organic farms did not increase mortality of a novel herbivore used to bioassay ecosystem service. The explanation for these differences is likely to include inherent differences in management strategies and landscape structure between the two farming systems.

  20. Evaluation Of Batu Bumbun Sanctuary Ecosystem And Management Strategy Affected By Climate Change In Mahakam Watershed Kutai Kartanegara Indonesia

    Directory of Open Access Journals (Sweden)

    Lariman

    2015-08-01

    Full Text Available Batu Bumbun Sanctuary Middle Mahakam Lake is very important for the fishermen community and Mahakam Irrawaddy Dolphin life concerned to its function as the source of fish and as the feeding ground of Irrawaddy Dolphin Orcaella brevirostris. The changes in the forest function and the climate such as rainfall and water surfaces are predicted to have caused suppression in the ecosystem of Batu Bumbun Sanctuary. The aim of this study is to evaluate the current ecosystem changes of Batu Bumbun Sanctuary and suggest a suitable management strategy as a way to conserve its function. The research was conducted during the dry season April June and rainy season November December 2014 by using survey methods. The measured parameters were including water quality DO pH temperature TSS TDS alkalinity and clarity vegetation composition rainfall water surface elevation and sediment. The data of fish community were analysed by using Shanon-Wiener index. The result showed that 1 The current condition of Batu Bumbun biophysical ecosystem has been experiencing a heavy degradation showed by a high fluctuation of the water surface in two extreme seasons such as the flood in rainy seasons and silt up in the dry season. 2 The vegetation composition in the riverbanks was composed of five species including Bungur Lagerstroemia speciosa Rambai Punai Chaetocarpus Castano carpus Kendikara Dillenia excelsa Kademba Mytragina speciosa and Rengas Gluta renghas. The dominant tree species was Putat Barringtonia asiatica and Perupuk Lophopetalum javanicum. 3 Batu Bumbun Sanctuary has been experiencing a heavy siltation caused by silt material that piles up the weeds during the rainy season. Since 1985 Batu Bumbun was predicted to have rates of silting around 8 cmyear. From those result it can be concluded that Batu Bumbun has been experiencing a heavy degradation showed by a high fluctuation of water surface vegetation composition and heavy siltation. Then the most suitable

  1. Climate control of terrestrial carbon exchange across biomes and continents

    DEFF Research Database (Denmark)

    Yi, Chuixiang; Ricciuto, Daniel; Li, Runze

    2010-01-01

    Understanding the relationships between climate and carbon exchange by terrestrial ecosystems is critical to predict future levels of atmospheric carbon dioxide because of the potential accelerating effects of positive climate–carbon cycle feedbacks. However, directly observed relationships betwe...

  2. Climate control of terrestrial carbon exchange across biomes and continents

    NARCIS (Netherlands)

    Yi, C.; Ricciuto, D.; Li, R.; Hendriks, D.M.D.; Moors, E.J.; Valentini, R.

    2010-01-01

    Understanding the relationships between climate and carbon exchange by terrestrial ecosystems is critical to predict future levels of atmospheric carbon dioxide because of the potential accelerating effects of positive climate-carbon cycle feedbacks. However, directly observed relationships between

  3. Climate control of terrestrial carbon exchange across biomes and continents

    NARCIS (Netherlands)

    Yi, C.; Jacobs, C.M.J.; Moors, E.J.; Elbers, J.A.

    2010-01-01

    Understanding the relationships between climate and carbon exchange by terrestrial ecosystems is critical to predict future levels of atmospheric carbon dioxide because of the potential accelerating effects of positive climate–carbon cycle feedbacks. However, directly observed relationships between

  4. Depletion of serotonin selectively impairs short-term memory without affecting long-term memory in odor learning in the terrestrial slug Limax valentianus.

    Science.gov (United States)

    Shirahata, Takaaki; Tsunoda, Makoto; Santa, Tomofumi; Kirino, Yutaka; Watanabe, Satoshi

    2006-01-01

    The terrestrial slug Limax is able to acquire short-term and long-term memories during aversive odor-taste associative learning. We investigated the effect of the selective serotonergic neurotoxin 5,7-dihydroxytryptamine (5,7-DHT) on memory. Behavioral studies indicated that 5,7-DHT impaired short-term memory but not long-term memory. HPLC (high-performance liquid chromatography) analysis revealed that 5,7-DHT significantly reduced serotonin content in the central nervous system. The present study suggests that acquisition, retention, and/or retrieval of short-term memory involves serotonin, and neither acquisition nor retrieval of long-term memory requires serotonin at a level as high as that required for short-term memory.

  5. Affect

    NARCIS (Netherlands)

    Cetinic, M.; Diamanti, J.; Szeman, I.; Blacker, S.; Sully, J.

    2017-01-01

    This chapter historicizes four divergent but historically contemporaneous genres of affect theory – romantic, realist, speculative, and materialist. While critics credited with the turn to affect in the 1990s wrote largely in the wake of poststructuralism from the perspective of gender and queer

  6. Water stress and harmful insects in agri-forest ecosystems

    Directory of Open Access Journals (Sweden)

    Mario Solinas

    2010-09-01

    Full Text Available Present knowledge on ecological services supplied by insects to natural terrestrial ecosystems, allow us to identify many homeostatic mechanisms regulating biological balance as well as life perpetuation of the said ecosystems; at the same time, that knowledge represents a sound referring point to understanding how those mechanisms do work so as to manage them in the anthropized ecosystems (i.e., agriculture and forests, and especially in order to identify in the latter the natural meaning of the so called insect outbreaks, so as to forecast and possibly prevent them; as well as, when needed, to conceive and formulate efficient control strategies having minimal environmental impact. Water factor is crucial with genesis, configuration and conservation of a terrestrial ecosystem (both natural or anthropized as a whole or in its individual components, but especially concerning plant life as well as plant interactions with phytophagous invertebrates, mainly insects. Insect-plant trophic interactions are principally influenced by the water conditions in the ecosystem, and the impact of phytophagous insects on crops is markedly affected. Extremely severe water stress, especially if prolonged, prevent insect life just like plant’s life but a moderate and not so prolonged water stress, while depressing plant vigour, paradoxically can improve development and multiplication of phytophagous arthropods, with severe consequences on woody plants especially, and forest trees markedly.

  7. Water stress and harmful insects in agri-forest ecosystems

    Directory of Open Access Journals (Sweden)

    Mario Solinas

    2011-02-01

    Full Text Available Present knowledge on ecological services supplied by insects to natural terrestrial ecosystems, allow us to identify many homeostatic mechanisms regulating biological balance as well as life perpetuation of the said ecosystems; at the same time, that knowledge represents a sound referring point to understanding how those mechanisms do work so as to manage them in the anthropized ecosystems (i.e., agriculture and forests, and especially in order to identify in the latter the natural meaning of the so called insect outbreaks, so as to forecast and possibly prevent them; as well as, when needed, to conceive and formulate efficient control strategies having minimal environmental impact. Water factor is crucial with genesis, configuration and conservation of a terrestrial ecosystem (both natural or anthropized as a whole or in its individual components, but especially concerning plant life as well as plant interactions with phytophagous invertebrates, mainly insects. Insect-plant trophic interactions are principally influenced by the water conditions in the ecosystem, and the impact of phytophagous insects on crops is markedly affected. Extremely severe water stress, especially if prolonged, prevent insect life just like plant’s life but a moderate and not so prolonged water stress, while depressing plant vigour, paradoxically can improve development and multiplication of phytophagous arthropods, with severe consequences on woody plants especially, and forest trees markedly.

  8. Water stress and harmful insects in agri-forest ecosystems

    Directory of Open Access Journals (Sweden)

    Mario Solinas

    Full Text Available Present knowledge on ecological services supplied by insects to natural terrestrial ecosystems, allow us to identify many homeostatic mechanisms regulating biological balance as well as life perpetuation of the said ecosystems; at the same time, that knowledge represents a sound referring point to understanding how those mechanisms do work so as to manage them in the anthropized ecosystems (i.e., agriculture and forests, and especially in order to identify in the latter the natural meaning of the so called insect outbreaks, so as to forecast and possibly prevent them; as well as, when needed, to conceive and formulate efficient control strategies having minimal environmental impact. Water factor is crucial with genesis, configuration and conservation of a terrestrial ecosystem (both natural or anthropized as a whole or in its individual components, but especially concerning plant life as well as plant interactions with phytophagous invertebrates, mainly insects. Insect-plant trophic interactions are principally influenced by the water conditions in the ecosystem, and the impact of phytophagous insects on crops is markedly affected. Extremely severe water stress, especially if prolonged, prevent insect life just like plant’s life but a moderate and not so prolonged water stress, while depressing plant vigour, paradoxically can improve development and multiplication of phytophagous arthropods, with severe consequences on woody plants especially, and forest trees markedly.

  9. Scorched Earth: how will changes in the strength of the vegetation sink to ozone deposition affect human health and ecosystems?

    Directory of Open Access Journals (Sweden)

    L. D. Emberson

    2013-07-01

    Full Text Available This study investigates the effect of ozone (O3 deposition on ground level O3 concentrations and subsequent human health and ecosystem risk under hot summer "heat wave" type meteorological events. Under such conditions, extended drought can effectively "turn off" the O3 vegetation sink leading to a substantial increase in ground level O3 concentrations. Two models that have been used for human health (the CMAQ chemical transport model and ecosystem (the DO3SE O3 deposition model risk assessment are combined to provide a powerful policy tool capable of novel integrated assessments of O3 risk using methods endorsed by the UNECE Convention on Long-Range Transboundary Air Pollution. This study investigates 2006, a particularly hot and dry year during which a heat wave occurred over the summer across much of the UK and Europe. To understand the influence of variable O3 dry deposition three different simulations were investigated during June and July: (i actual conditions in 2006, (ii conditions that assume a perfect vegetation sink for O3 deposition and (iii conditions that assume an extended drought period that reduces the vegetation sink to a minimum. The risks of O3 to human health, assessed by estimating the number of days during which running 8 h mean O3 concentrations exceeded 100 μg m−3, show that on average across the UK, there is a difference of 16 days exceedance of the threshold between the perfect sink and drought conditions. These average results hide local variation with exceedances between these two scenarios reaching as high as 20 days in the East Midlands and eastern UK. Estimates of acute exposure effects show that O3 removed from the atmosphere through dry deposition during the June and July period would have been responsible for approximately 460 premature deaths. Conversely, reduced O3 dry deposition will decrease the amount of O3 taken up by vegetation and, according to flux-based assessments of vegetation damage, will lead

  10. Climate control of terrestrial carbon exchange across biomes and continents

    Science.gov (United States)

    Chuixiang Yi; Daniel Ricciuto; Runze Li; John Wolbeck; Xiyan Xu; Mats Nilsson; John Frank; William J. Massman

    2010-01-01

    Understanding the relationships between climate and carbon exchange by terrestrial ecosystems is critical to predict future levels of atmospheric carbon dioxide because of the potential accelerating effects of positive climate-carbon cycle feedbacks. However, directly observed relationships between climate and terrestrial CO2 exchange with the atmosphere across biomes...

  11. Root dynamics in an artificially constructed regenerating longleaf pine ecosystem are affected by atmospheric CO(2) enrichment.

    Science.gov (United States)

    Pritchard, S G.; Davis, M A.; Mitchell, R J.; Prior, S A.; Boykin, D L.; Rogers, H H.; Runion, G B.

    2001-08-01

    Differential responses to elevated atmospheric CO(2) concentration exhibited by different plant functional types may alter competition for above- and belowground resources in a higher CO(2) world. Because C allocation to roots is often favored over C allocation to shoots in plants grown with CO(2) enrichment, belowground function of forest ecosystems may change significantly. We established an outdoor facility to examine the effects of elevated CO(2) on root dynamics in artificially constructed communities of five early successional forest species: (1) a C(3) evergreen conifer (longleaf pine, Pinus palustris Mill.); (2) a C(4) monocotyledonous bunch grass (wiregrass, Aristida stricta Michx.); (3) a C(3) broadleaf tree (sand post oak, Quercus margaretta); (4) a C(3) perennial herbaceous legume (rattlebox, Crotalaria rotundifolia Walt. ex Gemel); and (5) an herbaceous C(3) dicotyledonous perennial (butterfly weed, Asclepias tuberosa L.). These species are common associates in early successional longleaf pine savannahs throughout the southeastern USA and represent species that differ in life-form, growth habit, physiology, and symbiotic relationships. A combination of minirhizotrons and soil coring was used to examine temporal and spatial rooting dynamics from October 1998 to October 1999. CO(2)-enriched plots exhibited 35% higher standing root crop length, 37% greater root length production per day, and 47% greater root length mortality per day. These variables, however, were enhanced by CO(2) enrichment only at the 10-30 cm depth. Relative root turnover (flux/standing crop) was unchanged by elevated CO(2). Sixteen months after planting, root biomass of pine was 62% higher in elevated compared to ambient CO(2) plots. Conversely, the combined biomass of rattlebox, wiregrass, and butterfly weed was 28% greater in ambient compared to high CO(2) plots. There was no difference in root biomass of oaks after 16 months of exposure to elevated CO(2). Using root and shoot

  12. Impact of non-native terrestrial mammals on the structure of the terrestrial mammal food web of Newfoundland, Canada.

    Directory of Open Access Journals (Sweden)

    Justin S Strong

    Full Text Available The island of Newfoundland is unique because it has as many non-native terrestrial mammals as native ones. The impacts of non-native species on native flora and fauna can be profound and invasive species have been identified as one of the primary drivers of species extinction. Few studies, however, have investigated the effects of a non-native species assemblage on community and ecosystem properties. We reviewed the literature to build the first terrestrial mammal food web for the island of Newfoundland and then used network analyses to investigate how the timing of introductions and trophic position of non-native species has affected the structure of the terrestrial mammal food web in Newfoundland. The first non-native mammals (house mouse and brown rat became established in Newfoundland with human settlement in the late 15th and early 16th centuries. Coyotes and southern red-backed voles are the most recent mammals to establish themselves on the island in 1985 and 1998, respectively. The fraction of intermediate species increased with the addition of non-native mammals over time whereas the fraction of basal and top species declined over time. This increase in intermediate species mediated by non-native species arrivals led to an overall increase in the terrestrial mammal food web connectance and generality (i.e. mean number of prey per predator. This diverse prey base and sources of carrion may have facilitated the natural establishment of coyotes on the island. Also, there is some evidence that the introduction of non-native prey species such as the southern red-backed vole has contributed to the recovery of the threatened American marten. Long-term monitoring of the food web is required to understand and predict the impacts of the diverse novel interactions that are developing in the terrestrial mammal food web of Newfoundland.

  13. Millennium Ecosystem Assessment: MA Ecosystems

    Data.gov (United States)

    National Aeronautics and Space Administration — The Millennium Ecosystem Assessment: MA Ecosystems provides data and information on the extent and classification of ecosystems circa 2000, including coastal,...

  14. Climate, ecosystems, and planetary futures: The challenge to predict life in Earth system models.

    Science.gov (United States)

    Bonan, Gordon B; Doney, Scott C

    2018-02-02

    Many global change stresses on terrestrial and marine ecosystems affect not only ecosystem services that are essential to humankind, but also the trajectory of future climate by altering energy and mass exchanges with the atmosphere. Earth system models, which simulate terrestrial and marine ecosystems and biogeochemical cycles, offer a common framework for ecological research related to climate processes; analyses of vulnerability, impacts, and adaptation; and climate change mitigation. They provide an opportunity to move beyond physical descriptors of atmospheric and oceanic states to societally relevant quantities such as wildfire risk, habitat loss, water availability, and crop, fishery, and timber yields. To achieve this, the science of climate prediction must be extended to a more multifaceted Earth system prediction that includes the biosphere and its resources. Copyright © 2018, American Association for the Advancement of Science.

  15. Understanding and Projecting Climate and Human Impacts on Terrestrial-Coastal Carbon and Nutrient Fluxes

    Science.gov (United States)

    Lohrenz, S. E.; Cai, W. J.; Tian, H.; He, R.; Fennel, K.

    2017-12-01

    Changing climate and land use practices have the potential to dramatically alter coupled hydrologic-biogeochemical processes and associated movement of water, carbon and nutrients through various terrestrial reservoirs into rivers, estuaries, and coastal ocean waters. Consequences of climate- and land use-related changes will be particularly evident in large river basins and their associated coastal outflow regions. Here, we describe a NASA Carbon Monitoring System project that employs an integrated suite of models in conjunction with remotely sensed as well as targeted in situ observations with the objectives of describing processes controlling fluxes on land and their coupling to riverine, estuarine and ocean ecosystems. The nature of our approach, coupling models of terrestrial and ocean ecosystem dynamics and associated carbon processes, allows for assessment of how societal and human-related land use, land use change and forestry and climate-related change affect terrestrial carbon transport as well as export of materials through watersheds to the coastal margins. Our objectives include the following: 1) Provide representation of carbon processes in the terrestrial ecosystem to understand how changes in land use and climatic conditions influence the export of materials to the coastal ocean, 2) Couple the terrestrial exports of carbon, nutrients and freshwater to a coastal biogeochemical model and examine how different climate and land use scenarios influence fluxes across the land-ocean interface, and 3) Project future changes under different scenarios of climate and human impact, and support user needs related to carbon management and other activities (e.g., water quality, hypoxia, ocean acidification). This research is providing information that will contribute to determining an overall carbon balance in North America as well as describing and predicting how human- and climate-related changes impact coastal water quality including possible effects of coastal

  16. Cross-Sectoral Resource Management: How Forest Management Alternatives Affect the Provision of Biomass and Other Ecosystem Services

    Directory of Open Access Journals (Sweden)

    Susanne Frank

    2015-02-01

    Full Text Available Integrated forest management is faced with the challenge that the contribution of forests to economic and ecological planning targets must be assessed in a socio-ecological system context. This paper introduces a way to model spatio-temporal dynamics of biomass production at a regional scale in order to derive land use strategies that enhance biomass provision and avoid trade-offs for other ecosystem services. The software platform GISCAME was employed to bridge the gap between local land management decisions and regional planning by linking growth and yield models with an integrative mesoscale modeling and assessment approach. The model region is located in Saxony, Germany. Five scenarios were simulated, which aimed at testing different alternatives for adapted land use in the context of climate change and increasing biomass demand. The results showed, for example, that forest conversion towards climate-change-adapted forest types had positive effects on ecological integrity and landscape aesthetics. In contrast, negative impacts on landscape aesthetics must be expected if agricultural sites were converted into short rotation coppices. Uncertainties with stem from assumptions regarding growth and yield models were discussed. Future developmental steps which consider, for example, accessibility of the resources were identified.

  17. Winter climate change affects growing-season soil microbial biomass and activity in northern hardwood forests

    Science.gov (United States)

    Jorge Durán; Jennifer L. Morse; Peter M. Groffman; John L. Campbell; Lynn M. Christenson; Charles T. Driscoll; Timothy J. Fahey; Melany C. Fisk; Myron J. Mitchell; Pamela H. Templer

    2014-01-01

    Understanding the responses of terrestrial ecosystems to global change remains a major challenge of ecological research. We exploited a natural elevation gradient in a northern hardwood forest to determine how reductions in snow accumulation, expected with climate change, directly affect dynamics of soil winter frost, and indirectly soil microbial biomass and activity...

  18. Effect of interannual climate variability on carbon storage in Amazonian ecosystems

    Science.gov (United States)

    Tian, H.; Melillo, J.M.; Kicklighter, D.W.; McGuire, David A.; Helfrich, J. V. K.; Moore, B.; Vorosmarty, C.J.

    1998-01-01

    The Amazon Basin contains almost one-half of the world's undisturbed tropical evergreen forest as well as large areas of tropical savanna. The forests account for about 10 per cent of the world's terrestrial primary productivity and for a similar fraction of the carbon stored in land ecosystems, and short-term field measurements suggest that these ecosystems are globally important carbon sinks. But tropical land ecosystems have experienced substantial interannual climate variability owing to frequent El Nino episodes in recent decades. Of particular importance to climate change policy is how such climate variations, coupled with increases in atmospheric CO2 concentration, affect terrestrial carbon storage. Previous model analyses have demonstrated the importance of temperature in controlling carbon storage. Here we use a transient process-based biogeochemical model of terrestrial ecosystems to investigate interannual variations of carbon storage in undisturbed Amazonian ecosystems in response to climate variability and increasing atmospheric CO2 concentration during the period 1980 to 1994. In El Nino years, which bring hot, dry weather to much of the Amazon region, the ecosystems act as a source of carbon to the atmosphere (up to 0.2 petagrams of carbon in 1987 and 1992). In other years, these ecosystems act as a carbon sink (up to 0.7 Pg C in 1981 and 1993). These fluxes are large; they compare to a 0.3 Pg C per year source to the atmosphere associated with deforestation in the Amazon Basin in the early 1990s. Soil moisture, which is affected by both precipitation and temperature, and which affects both plant and soil processes, appears to be an important control on carbon storage.

  19. List identifies threatened ecosystems

    Science.gov (United States)

    Showstack, Randy

    2012-09-01

    The International Union for Conservation of Nature (IUCN) announced on 9 September that it will develop a new Red List of Ecosystems that will identify which ecosystems are vulnerable or endangered. The list, which is modeled on the group's Red List of Threatened Species™, could help to guide conservation activities and influence policy processes such as the Convention on Biological Diversity, according to the group. “We will assess the status of marine, terrestrial, freshwater, and subterranean ecosystems at local, regional, and global levels,” stated Jon Paul Rodriguez, leader of IUCN's Ecosystems Red List Thematic Group. “The assessment can then form the basis for concerted implementation action so that we can manage them sustainably if their risk of collapse is low or restore them if they are threatened and then monitor their recovery.”

  20. Impacts of elevated atmospheric CO2 on litter quality, litter decomposability and nitrogen turnover rate of two oak species in a Mediterranean forest ecosystem

    NARCIS (Netherlands)

    Fayez Raiesi Gahrooee,

    1998-01-01

    Elevated CO2 may affect litter quality of plants, and subsequently C and N cycling in terrestrial ecosystems, but changes in litter quality associated with elevated CO2 are poorly known. Abscised leaf litter of two oak species (Quercus cerris L., and Q. pubescens Willd.) exposed to long-term

  1. The circumpolar biodiversity monitoring program - Terrestrial plan

    DEFF Research Database (Denmark)

    Christensen, Tom; Payne, J.; Doyle, M.

    , northern communities, and scientists to detect, understand and report on long-term change in Arctic terrestrial ecosystems and biodiversity. This presentation will outline the key management questions the plan aims to address and the proposed nested, multi-scaled approach linking targeted, research based...... monitoring with survey-based monitoring and remotely sensed data. The CBMP Terrestrial Plan intends to build upon and expand existing monitoring networks, engaging participants across a range of capacity and interests. The presentation will summarize the recommended focal soil ecosystem components...... and attributes to monitor in the plan related to soil invertebrates. Focal Ecosystem Components (FECs) of the soil decomposer system include the soil living invertebrates such as microarthropods, enchytraeids and earthworms and the functions performed by microorganisms such as nitrification, decomposition...

  2. A framework to assess biogeochemical response to ecosystem disturbance using nutrient partitioning ratios

    Science.gov (United States)

    Kranabetter, J. Marty; McLauchlan, Kendra K.; Enders, Sara K.; Fraterrigo, Jennifer M.; Higuera, Philip E.; Morris, Jesse L.; Rastetter, Edward B.; Barnes, Rebecca; Buma, Brian; Gavin, Daniel G.; Gerhart, Laci M.; Gillson, Lindsey; Hietz, Peter; Mack, Michelle C.; McNeil, Brenden; Perakis, Steven

    2016-01-01

    Disturbances affect almost all terrestrial ecosystems, but it has been difficult to identify general principles regarding these influences. To improve our understanding of the long-term consequences of disturbance on terrestrial ecosystems, we present a conceptual framework that analyzes disturbances by their biogeochemical impacts. We posit that the ratio of soil and plant nutrient stocks in mature ecosystems represents a characteristic site property. Focusing on nitrogen (N), we hypothesize that this partitioning ratio (soil N: plant N) will undergo a predictable trajectory after disturbance. We investigate the nature of this partitioning ratio with three approaches: (1) nutrient stock data from forested ecosystems in North America, (2) a process-based ecosystem model, and (3) conceptual shifts in site nutrient availability with altered disturbance frequency. Partitioning ratios could be applied to a variety of ecosystems and successional states, allowing for improved temporal scaling of disturbance events. The generally short-term empirical evidence for recovery trajectories of nutrient stocks and partitioning ratios suggests two areas for future research. First, we need to recognize and quantify how disturbance effects can be accreting or depleting, depending on whether their net effect is to increase or decrease ecosystem nutrient stocks. Second, we need to test how altered disturbance frequencies from the present state may be constructive or destructive in their effects on biogeochemical cycling and nutrient availability. Long-term studies, with repeated sampling of soils and vegetation, will be essential in further developing this framework of biogeochemical response to disturbance.

  3. Examination of ecosystems affected by the Chernobyl reactor accident and assessment of resulting radiation exposure of the population

    International Nuclear Information System (INIS)

    Fielitz, U.

    2001-01-01

    Since 1988, within the scope of several research projects, in 7,000 samples of soil, plants, mushrooms and game from forest ecosystems, the 137 Cs activity concentration was measured, in order to investigate the dynamics of the nuclide. The investigation sites are a spruce mountain forest near the village Bodenmais (Bavaria) and an oak forest close to Fuhrberg (Lower Saxony). In both forests, unfavourable location conditions cause a relativ high transfer of 137 Cs into plants and game. Typifying for the 3 forest sites was the high intra- and interspecies variablilty of the 137 Cs activity concentration. Even 14 years after the Chernobyl-fallout at the 3 investigation sites, the average 137 Cs inventory, contained in the top 10 cm of soil was 56% and 93% in the top 20 cm. From 1987 till 1994, in the leaves of the investigated plant species the 137 Cs activity concentration decreased significant, during the following years there was little change. The effective half life of 137 Cs varies between -3 years for raspberry and -24 years for the fern Pteridium aquillinum, whereas most of the plant species show half lifes of about -5 years. In 2000, as usual mushrooms from the Bodenmais investigation site showed the highest 137 Cs contaminations. The aggregated transfer factors (T agg ) for soil → plant and soil → flesh varied with several orders of magnitude. T agg values for Soil → autotroph plant species reached from 0,0001 m 2 .kg -1 to 0,41 m 2 .kg -1 . While at the permanent study plots in Bodenmais and Fuhrberg the T agg values were of comparable quantity, at Goettingen, they were lower than two orders of magnitude. For example T agg for Cs-137 in wild boar from Bodenmais was 392 times higher than for wild boar from Goettingen. From 1987 till 2000, the 137 Cs activity in roe-deer from Bodenmais varied according to the seasons, with highest values in autumn, and lowest values in spring. In consequence of the decrease of the 137 Cs activity concentration in

  4. The Romanian legislative framework for protection of terrestrial and freshwater vertebrate tetrapodes potentially affected by activities for exploitation of wind-resources

    Directory of Open Access Journals (Sweden)

    TÖRÖK Zsolt

    2008-10-01

    Full Text Available The Romanian legislation nominates for variosus conservative statuses the following terrestrial or freshwater tetrapode species which should be included in the analyses of teh studies on the potential negative impact of wind-turbines and related infrastructures or activities: 11 species of amphibians, 16 species of reptiles, 273 species of birds and 38 species of mammals that have “strictly protected species” status (according to ActNo. 13 / 1993, which enforces the Bern Convention on conservation of wildlife; 7 species of amphibians, 5 species ofreptiles, 94 species of birds and 31 species of mammals that have “protected species” status (according to the same ActNo. 13 / 1993; 6 species of amphibians, 5 species of reptiles, 54 species of mammals of which protection needs designaton of Special Areas of Conservation (Governmental Urgency Ordinance No. 57 / 2007; 11 species of amphibians, 18 species of reptiles, 48 species of mammals having “Species of Community Interest that need strictprotection” status (Governmental Urgency Ordinance No. 57 / 2007; 6 species of amphibians, 5 species of reptiles, 67 species of birds and 6 species of mammals that have “Species of National Interest that need strict protection” status (Governmental Urgency Ordinance No. 57 / 2007. At least 122 species of birds are nominated among the species of which protection needs designaton of Special Protection Areas (Governmental Urgency Ordinance No. 57 / 2007, 112migratory waterbird species are protected by Act No. 89 / 2000, 20 migratory birds are considered as being treathened on European level (Act no. 13 / 1998 and 267 species have “unfavourable status on European level” (Act no. 13 / 1998. All 30 bat species are protected by Act No. 90 / 2000, and 25 species are also nominated in Act No. 13 / 1993 (that enforces the Bonn Convention on migratory species.

  5. Terrestrial Carbon [Environmental Pollution: Part I, Special Issue, March 2002; Part II, Special Issue Supplement to 116/3, 2002

    Energy Technology Data Exchange (ETDEWEB)

    Mickler, Robert (ed.); McNulty, Steven (ed.)

    2002-03-01

    These issues contain a total of forty-four peer reviewed science papers on terrestrial carbon presented at the Advances in Terrestrial Ecosystem Carbon Inventory, Measurements, and Monitoring Conference held in Raleigh, N.C., in October 2000.

  6. Data-driven diagnostics of terrestrial carbon dynamics over North America

    Science.gov (United States)

    Jingfeng Xiao; Scott V. Ollinger; Steve Frolking; George C. Hurtt; David Y. Hollinger; Kenneth J. Davis; Yude Pan; Xiaoyang Zhang; Feng Deng; Jiquan Chen; Dennis D. Baldocchi; Bevery E. Law; M. Altaf Arain; Ankur R. Desai; Andrew D. Richardson; Ge Sun; Brian Amiro; Hank Margolis; Lianhong Gu; Russell L. Scott; Peter D. Blanken; Andrew E. Suyker

    2014-01-01

    The exchange of carbon dioxide is a key measure of ecosystem metabolism and a critical intersection between the terrestrial biosphere and the Earth's climate. Despite the general agreement that the terrestrial ecosystems in North America provide a sizeable carbon sink, the size and distribution of the sink remain uncertain. We use a data-driven approach to upscale...

  7. Examination of ecosystems affected by the Chernobyl reactor accident and assessment of resulting radiation exposure of the population

    International Nuclear Information System (INIS)

    Fielitz, U.

    1999-01-01

    This paper deals with investigations about the behaviour of radiocaesium, carried out in two selected forest ecosystems. In 1997 and 1998 samples from soil, plants, trees and roe deer from forest areas, located near Bodenmais (Bavaria) and Fuhrberg (Lower Saxony) were measured on the 137 Cs activity. In this areas intensive studies about the behaviour of radiocaesium were already carried out from 1987 until 1994, so that long term data are available. Investigations on vertical distribution of 137 Cs in soil were leaded through on permanent 100 x 100 m study plots. Even 11 years after the Chernobyl-fallout, the activity is highest in humic horizonts, only vestiges were found deeper than 20 cm in soil profile. The majority of total activity is still present in the upper 10 cm of soil. At the permant study plot B1 in Bodenmais in 1997 there were found about 78% of the 137 Cs activity concentration (100%=100830 Bq x m -2 ) in this layer, of what 27% were located in the 4 cm thick humic layer. Comparisons of the vertical distribution in 1998, 1992 and 1997 show, that the velocity of radiocesium migration takes down with time. From 1987 until 1998 the 137 Cs activity in leaves of different plant species decreased significant. The effective half life of 137 Cs varies between 5 years for raspberry (Rubus idaeus) and 33 years for fern (Pteridium aquillinum), whereby most of the plant species show half lifes of about 10 years. The 137 Cs activity-decline slowed down from 1994 until 1998. There were considerable differences in 137 Cs activity between various plant species. 1998 for example, the concentration of 137 Cs in samples, taken at the same time from the permanent study plot B1, ranged from 380 Bq x kg -1 (dry weight) in raspberry to 16800 Bq x kg -1 in fern (Dryopteris carthusiana). In muscle flesh of roe-deer of Bodenmais from 1987 until 1998 the 137 Cs activity varied according to the seasons, the highest values were found in autumn, the lowest values in spring. In

  8. The effects of atmospheric nitrogen deposition on terrestrial and freshwater biodiversity

    Science.gov (United States)

    Baron, Jill S.; Barber, Mary C.; Adams, Mark; Agboola, Julius I.; Allen, Edith B.; Bealey, William J.; Bobbink, Roland; Bobrovsky, Maxim V.; Bowman, William D.; Branquinho, Cristina; Bustamente, Mercedes M. C.; Clark, Christopher M.; Cocking, Edward C.; Cruz, Cristina; Davidson, Eric A.; Denmead, O. Tom; Dias, Teresa; Dise, Nancy B.; Feest, Alan; Galloway, James N.; Geiser, Linda H.; Gilliam, Frank S.; Harrison, Ian J.; Khanina, Larisa G.; Lu, Xiankai; Manrique, Esteban; Ochoa-Hueso, Raul; Ometto, Jean P. H. B.; Payne, Richard; Scheuschner, Thomas; Sheppard, Lucy J.; Simpson, Gavin L.; Singh, Y. V.; Stevens, Carly J.; Strachan, Ian; Sverdrup, Harald; Tokuchi, Naoko; van Dobben, Hans; Woodin, Sarah

    2014-01-01

    This chapter reports the findings of a Working Group on how atmospheric nitrogen (N) deposition affects both terrestrial and freshwater biodiversity. Regional and global scale impacts on biodiversity are addressed, together with potential indicators. Key conclusions are that: the rates of loss in biodiversity are greatest at the lowest and initial stages of N deposition increase; changes in species compositions are related to the relative amounts of N, carbon (C) and phosphorus (P) in the plant soil system; enhanced N inputs have implications for C cycling; N deposition is known to be having adverse effects on European and North American vegetation composition; very little is known about tropical ecosystem responses, while tropical ecosystems are major biodiversity hotspots and are increasingly recipients of very high N deposition rates; N deposition alters forest fungi and mycorrhyzal relations with plants; the rapid response of forest fungi and arthropods makes them good indicators of change; predictive tools (models) that address ecosystem scale processes are necessary to address complex drivers and responses, including the integration of N deposition, climate change and land use effects; criteria can be identified for projecting sensitivity of terrestrial and aquatic ecosystems to N deposition. Future research and policy-relevant recommendations are identified.

  9. Water-carbon Links in a Tropical Forest: How Interbasin Groundwater Flow Affects Carbon Fluxes and Ecosystem Carbon Budgets

    Energy Technology Data Exchange (ETDEWEB)

    Genereux, David [North Carolina State Univ., Raleigh, NC (United States); Osburn, Christopher [North Carolina State Univ., Raleigh, NC (United States); Oberbauer, Steven [Florida Intl Univ., Miami, FL (United States); Oviedo Vargas, Diana [North Carolina State Univ., Raleigh, NC (United States); Dierick, Diego [Florida Intl Univ., Miami, FL (United States)

    2017-03-27

    This report covers the outcomes from a quantitative, interdisciplinary field investigation of how carbon fluxes and budgets in a lowland tropical rainforest are affected by the discharge of old regional groundwater into streams, springs, and wetlands in the forest. The work was carried out in a lowland rainforest of Costa Rica, at La Selva Biological Station. The research shows that discharge of regional groundwater high in dissolved carbon dioxide represents a significant input of carbon to the rainforest "from below", an input that is on average larger than the carbon input "from above" from the atmosphere. A stream receiving discharge of regional groundwater had greatly elevated emissions of carbon dioxide (but not methane) to the overlying air, and elevated downstream export of carbon from its watershed with stream flow. The emission of deep geological carbon dioxide from stream water elevates the carbon dioxide concentrations in air above the streams. Carbon-14 tracing revealed the presence of geological carbon in the leaves and stems of some riparian plants near streams that receive inputs of regional groundwater. Also, discharge of regional groundwater is responsible for input of dissolved organic matter with distinctive chemistry to rainforest streams and wetlands. The discharge of regional groundwater in lowland surface waters has a major impact on the carbon cycle in this and likely other tropical and non-tropical forests.

  10. nitrogen saturation in stream ecosystems

    OpenAIRE

    Earl, S. R.; Valett, H. M.; Webster, J. R.

    2006-01-01

    The concept of nitrogen (N) saturation has organized the assessment of N loading in terrestrial ecosystems. Here we extend the concept to lotic ecosystems by coupling Michaelis-Menten kinetics and nutrient spiraling. We propose a series of saturation response types, which may be used to characterize the proximity of streams to N saturation. We conducted a series of short-term N releases using a tracer ((NO3)-N-15-N) to measure uptake. Experiments were conducted in streams spanning a gradient ...

  11. Radio-capacity of ecosystems

    International Nuclear Information System (INIS)

    Kultakhmedov, Yu.; Kultakhmedova-Vyshnyakova, V.

    1997-01-01

    This paper consider a universal approach to ecosystems of different types, based on representation of their radio-capacity. The concept of ecosystem includes reproduction of components (bio-productivity) and conditions such as maintaining of environment quality. Radio-capacity in the case of radionuclide pollution appears in accumulation and redistribution of radionuclides in the ecosystem. As a result the radionuclides are redistributed and buried in soil or lake bottom sediments. Estimation models for the radio-capacity of water and terrestrial ecosystems are represented. The calculations of the radio-capacity factor of water ecosystems are performed, and the high radio-capacity of a freshwater reservoir (F=0.6-0.8) and extremely high radio-capacity of a reservoir cascade (F c =0.99) is shown material from the Dnieper's cascade reservoirs. The methods of radio-capacity estimation of agroecosystems, wood and marine ecosystems are developed. (authors)

  12. Response of the Eastern Mediterranean microbial ecosystem to dust and dust affected by acid processing in the atmosphere

    Directory of Open Access Journals (Sweden)

    Michael David Krom

    2016-08-01

    Full Text Available Acid processes in the atmosphere, particularly those caused by anthropogenic acid gases, increase the amount of bioavailable P in dust and hence are predicted to increase microbial biomass and primary productivity when supplied to oceanic surface waters. This is likely to be particularly important in the Eastern Mediterranean Sea (EMS, which is P limited during the winter bloom and N&P co-limited for phytoplankton in summer. However, it is not clear how the acid processes acting on Saharan dust will affect the microbial biomass and primary productivity in the EMS. Here, we carried out bioassay manipulations on EMS surface water on which Saharan dust was added as dust (Z, acid treated dust (ZA, dust plus excess N (ZN and acid treated dust with excess N (ZNA during springtime (May 2012 and measured bacterioplankton biomass, metabolic and other relevant chemical and biological parameters. We show that acid treatment of Saharan dust increased the amount of bioavailable P supplied by a factor of ~40 compared to non-acidified dust (18.4 nmoles P mg-1 dust vs. 0.45 nmoles P mg-1 dust, respectively. The increase in chlorophyll, primary and bacterial productivity for treatments Z and ZA were controlled by the amount of N added with the dust while those for treatments ZN and ZNA (in which excessive N was added were controlled by the amount of P added. These results confirm that the surface waters were N&P co-limited for phytoplankton during springtime. However, total chlorophyll and primary productivity in the acid treated dust additions (ZA and ZNA were less than predicted from that calculated from the amount of the potentially limiting nutrient added. This biological inhibition was interpreted as being due to labile trace metals being added with the acidified dust. A probable cause for this biological inhibition was the addition of dissolved Al, which forms potentially toxic Al nanoparticles when added to seawater. Thus, the effect of anthropogenic acid

  13. Ecosystem Services

    Science.gov (United States)

    Ecosystem goods and services are the many life-sustaining benefits we receive from nature and contribute to environmental and human he