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Sample records for affects ecosystem processes

  1. Soil biota can change after exotic plant invasion: Does this affect ecosystem processes?

    USGS Publications Warehouse

    Belnap, J.; Phillips, S.L.; Sherrod, S.K.; Moldenke, A.

    2005-01-01

    Invasion of the exotic annual grass Bromus tectorum into stands of the native perennial grass Hilaria jamesii significantly reduced the abundance of soil biota, especially microarthropods and nematodes. Effects of invasion on active and total bacterial and fungal biomass were variable, although populations generally increased after 50+ years of invasion. The invasion of Bromus also resulted in a decrease in richness and a species shift in plants, microarthropods, fungi, and nematodes. However, despite the depauperate soil fauna at the invaded sites, no effects were seen on cellulose decomposition rates, nitrogen mineralization rates, or vascular plant growth. When Hilaria was planted into soils from not-invaded, recently invaded, and historically invaded sites (all currently or once dominated by Hilaria), germination and survivorship were not affected. In contrast, aboveground Hilaria biomass was significantly greater in recently invaded soils than in the other two soils. We attributed the Hilaria response to differences in soil nutrients present before the invasion, especially soil nitrogen, phosphorus, and potassium, as these nutrients were elevated in the soils that produced the greatest Hilaria biomass. Our data suggest that it is not soil biotic richness per se that determines soil process rates or plant productivity, but instead that either (1) the presence of a few critical soil food web taxa can keep ecosystem function high, (2) nutrient loss is very slow in this ecosystem, and/or (3) these processes are microbially driven. However, the presence of Bromus may reduce key soil nutrients over time and thus may eventually suppress native plant success. ?? 2005 by the Ecological Society of America.

  2. Nutrient addition differentially affects ecological processes of Avicennia germinans in nitrogen versus phosphorus limited mangrove ecosystems

    USGS Publications Warehouse

    Feller, Ilka C.; Lovelock, C.E.; McKee, K.L.

    2007-01-01

    Nutrient over-enrichment is a major threat to marine environments, but system-specific attributes of coastal ecosystems may result in differences in their sensitivity and susceptibility to eutrophication. We used fertilization experiments in nitrogen (N)- and phosphorus (P)-limited mangrove forests to test the hypothesis that alleviating different kinds of nutrient limitation may have different effects on ecosystem structure and function in natural systems. We compared a broad range of ecological processes to determine if these systems have different thresholds where shifts might occur in nutrient limitation. Growth responses indicated N limitation in Avicennia germinans (black mangrove) forests in the Indian River Lagoon (IRL), Florida, and P limitation at Twin Cays, Belize. When nutrient deficiency was relieved, A. germinans grew out of its stunted form by increasing wood relative to leaf biomass and shoot length relative to lateral growth. At the P-limited site, P enrichment (+P) increased specific leaf area, N resorption, and P uptake, but had no effect on P resorption. At the N-limited site, +N increased both N and P resorption, but did not alter biomass allocation. Herbivory was greater at the P-limited site and was unaffected by +P, whereas +N led to increased herbivory at the N-limited site. The responses to nutrient enrichment depended on the ecological process and limiting nutrient and suggested that N- versus P-limited mangroves do have different thresholds. +P had a greater effect on more ecological processes at Twin Cays than did +N at the IRL, which indicated that the P-limited site was more sensitive to nutrient loading. Because of this sensitivity, eutrophication is more likely to cause a shift in nutrient limitation at P-limited Twin Cays than N-limited IRL. ?? 2007 Springer Science+Business Media, LLC.

  3. Implications for Ecosystem Services of Watershed Processes that affect the Transport and Transformations of Mercury in an Adirondack Stream Basin

    NASA Astrophysics Data System (ADS)

    Burns, D. A.; Riva-Murray, K.; Bradley, P. M.

    2012-12-01

    Mercury (Hg) is a potent neurotoxin that can affect the health of humans and wildlife through the ingestion of methyl Hg. Mercury contamination of ecosystems originates from human activities such as mining, coal burning and other industrial emissions, and the use of Hg-containing products. Natural sources such as volcanic and geothermal emissions and the weathering of Hg-bearing minerals also contribute to Hg contamination, but are believed to be minor sources in most ecosystems. Various ecosystem disturbances including fires, forest harvesting, and the submergence of land by impoundment may also contribute to Hg ecosystem contamination by mobilizing stores that have previously originated from the sources described above. Mercury from a mix of regional and global emissions sources is transported in the atmosphere to remote landscapes that are distant from local emissions sources. The Adirondacks of New York State is a forested, mountainous region characterized by abundant lakes and streams, and is distant from local emissions sources. Recreational fishing, wildlife viewing, hiking, and hunting are valued ecosystem services in this region. Here, we report on the relevance to ecosystem services of findings based on five years of Hg data collection of stream water, groundwater, invertebrates, and fish in the upper Hudson River basin in the central part of the Adirondack region. The New York State Dept. of Health has issued fish consumption advisories for the entire Adirondacks based on elevated levels previously measured in lakes and rivers of this region. Our work seeks improved understanding and models of the landscape sources and watershed processes that control the transformation of Hg to its methyl form (MeHg), the transport of MeHg to streams, and bioaccumulation of MeHg in aquatic food webs. Mean annual atmospheric Hg deposition was 6.3 μg/m2/yr during 2007-09, compared to mean annual filtered total Hg stream yields of 1.66 μg/m2/yr and filtered MeHg stream

  4. Determining place and process: functional traits of ectomycorrhizal fungi that affect both community structure and ecosystem function.

    PubMed

    Koide, Roger T; Fernandez, Christopher; Malcolm, Glenna

    2014-01-01

    There is a growing interest amongst community ecologists in functional traits. Response traits determine membership in communities. Effect traits influence ecosystem function. One goal of community ecology is to predict the effect of environmental change on ecosystem function. Environmental change can directly and indirectly affect ecosystem function. Indirect effects are mediated through shifts in community structure. It is difficult to predict how environmental change will affect ecosystem function via the indirect route when the change in effect trait distribution is not predictable from the change in response trait distribution. When response traits function as effect traits, however, it becomes possible to predict the indirect effect of environmental change on ecosystem function. Here we illustrate four examples in which key attributes of ectomycorrhizal fungi function as both response and effect traits. While plant ecologists have discussed response and effect traits in the context of community structuring and ecosystem function, this approach has not been applied to ectomycorrhizal fungi. This is unfortunate because of the large effects of ectomycorrhizal fungi on ecosystem function. We hope to stimulate further research in this area in the hope of better predicting the ecosystem- and landscape-level effects of the fungi as influenced by changing environmental conditions.

  5. Ash in fire affected ecosystems

    NASA Astrophysics Data System (ADS)

    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

  6. Ash in fire affected ecosystems

    NASA Astrophysics Data System (ADS)

    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

  7. Oceanographic and behavioural processes affecting invertebrate larval dispersal and supply in the western Iberia upwelling ecosystem

    NASA Astrophysics Data System (ADS)

    Queiroga, Henrique; Cruz, Teresa; dos Santos, Antonina; Dubert, Jesus; González-Gordillo, Juan Ignácio; Paula, José; Peliz, Álvaro; Santos, A. Miguel P.

    2007-08-01

    The present review addresses recent findings made in the western Iberia ecosystem on the behavioural and physical interactions that regulate dispersal, supply to coastal habitats and settlement of invertebrate larvae. These studies used the barnacle Chthamalus spp. and the crab Carcinus maenas as model organisms. The observations made on the Iberian shelf showed extensive diel vertical migrations along the water column by representatives of both groups that have never been reported before. The interaction of the diel vertical migration with the two-layer flow structure of upwelling/downwelling circulation suggests a mechanism that may help to retain larvae in shelf waters during upwelling conditions. Measurements of daily supply of C. maenas megalopae to estuaries separated by 500 km disclosed a semilunar pattern, with highest supply around highest amplitude tides, indicating that supply of megalopae to estuaries is accomplished by selective tidal stream transport. Relaxation of equatorward winds also played a role in supply, by enhancing translocation of megalopae to the nearshore. Concerning Chthamalus larvae, the observations on daily settlement made at rocky shores also separated by 500 km showed unclear patterns between locations and years. The relationship of settlement with water temperature, tidal range and upwelling indices indicated that supply of barnacle cyprids may be controlled by multiple mechanisms, viz. upwelling/downwelling circulation, internal tidal bores and sea breezes.

  8. The light: nutrient ratio in lakes: the balance of energy and materials affects ecosystem structure and process.

    PubMed

    Sterner, R W; Elser, J J; Fee, E J; Guildford, S J; Chrzanowski, T H

    1997-12-01

    The amounts of solar energy and materials are two of the chief factors determining ecosystem structure and process. Here, we examine the relative balance of light and phosphorus in a set of freshwater pelagic ecosystems. We calculated a ratio of light: phosphorus by putting mixed-layer mean light in the numerator and total P concentration in the denominator. This light: phosphorus ratio was a good predictor of the C:P ratio of particulate matter (seston), with a positive correlation demonstrated between these two ratios. We argue that the balance between light and nutrients controls "nutrient use efficiency" at the base of the food web in lakes. Thus, when light energy is high relative to nutrient availability, the base of the food web is carbon rich and phosphorus poor. In the opposite case, where light is relatively less available compared to nutrients, the base of the food web is relatively P rich. The significance of this relationship lies in the fact that the composition of sestonic material is known to influence a large number of ecosystem processes such as secondary production, nutrient cycling, and (we hypothesize) the relative strength of microbial versus grazing processes. Using the central result of increased C:P ratio with an increased light: phosphorus ratio, we make specific predictions of how ecosystem structure and process should vary with light and nutrient balance. Among these predictions, we suggest that lake ecosystems with low light: phosphorus ratios should have several trophic levels simultaneously carbon or energy limited, while ecosystems with high light: phosphorus ratios should have several trophic levels simultaneously limited by phosphorus. Our results provide an alternative perspective to the question of what determines nutrient use efficiency in ecosystems.

  9. Biogeochemical processes underpin ecosystem services

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Elemental cycling is critical to the function of ecosystems and delivery of key ecosystem services because many of these elements are essential nutrients or detrimental toxicants that directly affect the health of organisms and ecosystems. A team of authors from North Carolina State University and ...

  10. Subterranean ventilation: a key but poorly known process affecting the carbon balance of semi-arid ecosystems

    NASA Astrophysics Data System (ADS)

    López Ballesteros, Ana; Sánchez Cañete, Enrique P.; Serrano Ortiz, Penélope; Kowalski, Andrew S.; Oyonarte, Cecilio; Domingo, Francisco

    2016-04-01

    Subterranean ventilation, conceived as the advective transport of CO2-rich air from the vadose zone to the atmosphere through a porous media (i.e. soil or snow; Sánchez-Cañete et al., 2013), has arisen as an important process contributing to the carbon (C) balance of Mediterranean ecosystems (Kowalski et al., 2008; Sánchez-Cañete et al., 2011; Serrano-Ortiz et al., 2014), apart from other well-known biotic processes (i.e. plant photosynthesis, autotrophic and heterotrophic respiration). Recent studies have linked this subterranean CO2 release to fluctuations in the friction velocity or wind speed under drought conditions when water-free soil pores enable air transport (Rey et al., 2012a, 2013), however, barometric pressure variations has been suggested as another important driver (Sánchez-Cañete et al., 2013). In this study, we investigate this process in newly studied semi-arid grassland located in SE Spain, as the ideal ecosystem to do so given the great length of the dry season and the slight biotic activity limited to the winter season. Preliminary results, based on unpublished analyzed eddy covariance data and subterranean CO2 molar fraction measurements, confirm the presence of ventilation events from May to October for seven years 2009-2015. During these events, increases in the friction velocity correlates with sizeable CO2 emissions of up to ca.10 μmol m‑2 s‑1, and CO2 molar fraction regularly drops 2000-3000 ppm just after the turbulence peak, at several depths below the soil surface (0.15 and 1.5 m). Additionally, during the driest period (July-August), the friction velocity explains from 37% to 57% of the net C emission variability. On the other hand, the model residuals do not show a significant relationship, neither with air pressure nor with soil water content. Overall, the results found in this newly monitored site demonstrate, as shown by past research, the relevance of subterranean ventilation as a key process in the C balance of

  11. Subterranean ventilation: a key but poorly known process affecting the carbon balance of semi-arid ecosystems

    NASA Astrophysics Data System (ADS)

    López Ballesteros, Ana; Sánchez Cañete, Enrique P.; Serrano Ortiz, Penélope; Kowalski, Andrew S.; Oyonarte, Cecilio; Domingo, Francisco

    2016-04-01

    Subterranean ventilation, conceived as the advective transport of CO2-rich air from the vadose zone to the atmosphere through a porous media (i.e. soil or snow; Sánchez-Cañete et al., 2013), has arisen as an important process contributing to the carbon (C) balance of Mediterranean ecosystems (Kowalski et al., 2008; Sánchez-Cañete et al., 2011; Serrano-Ortiz et al., 2014), apart from other well-known biotic processes (i.e. plant photosynthesis, autotrophic and heterotrophic respiration). Recent studies have linked this subterranean CO2 release to fluctuations in the friction velocity or wind speed under drought conditions when water-free soil pores enable air transport (Rey et al., 2012a, 2013), however, barometric pressure variations has been suggested as another important driver (Sánchez-Cañete et al., 2013). In this study, we investigate this process in newly studied semi-arid grassland located in SE Spain, as the ideal ecosystem to do so given the great length of the dry season and the slight biotic activity limited to the winter season. Preliminary results, based on unpublished analyzed eddy covariance data and subterranean CO2 molar fraction measurements, confirm the presence of ventilation events from May to October for seven years 2009-2015. During these events, increases in the friction velocity correlates with sizeable CO2 emissions of up to ca.10 μmol m-2 s-1, and CO2 molar fraction regularly drops 2000-3000 ppm just after the turbulence peak, at several depths below the soil surface (0.15 and 1.5 m). Additionally, during the driest period (July-August), the friction velocity explains from 37% to 57% of the net C emission variability. On the other hand, the model residuals do not show a significant relationship, neither with air pressure nor with soil water content. Overall, the results found in this newly monitored site demonstrate, as shown by past research, the relevance of subterranean ventilation as a key process in the C balance of

  12. Processes affecting oxygen isotope ratios of atmospheric and ecosystem sulfate in two contrasting forest catchments in Central Europe.

    PubMed

    Novák, Martin; Mitchell, Myron J; Jacková, Iva; Buzek, Frantisek; Schweigstillová, Jana; Erbanová, Lucie; Prikryl, Richard; Fottová, Daniela

    2007-02-01

    Sulfate aerosols are harmful as respirable particles. They also play a role as cloud condensation nuclei and have radiative effects on global climate. A combination of delta18O-SO4 data with catchment sulfur mass balances was used to constrain processes affecting S cycling in the atmosphere and spruce forests of the Czech Republic. Extremely high S fluxes via spruce throughfall and runoff were measured at Jezeri (49 and 80 kg S ha(-1) yr(-1), respectively). The second catchment, Na Lizu, was 10 times less polluted. In both catchments, delta18O-SO4 decreased in the following order: open-area precipitation > throughfall > runoff. The delta18O-SO4 values of throughfall exhibited a seasonal pattern at both sites, with maxima in summer and minima in winter. This seasonal pattern paralleled delta18O-H2O values, which were offset by -18 per thousand. Sulfate in throughfall was predominantly formed by heterogeneous (aqueous) oxidation of SO2. Wet-deposited sulfate in an open area did not show systematic delta18O-SO4 trends, suggesting formation by homogeneous (gaseous) oxidation and/or transport from large distances. The percentage of incoming S that is organically cycled in soil was similar under the high and the low pollution. High-temperature 18O-rich sulfate was not detected, which contrasts with North American industrial sites.

  13. Processes affecting oxygen isotope ratios of atmospheric and ecosystem sulfate in two contrasting forest catchments in Central Europe

    SciTech Connect

    Martin Novak; Myron J. Mitchell; Iva Jackova; Frantisek Buzek; Jana Schweigstillova; Lucie Erbanova; Richard Prikryl; Daniela Fottova

    2007-02-15

    Sulfate aerosols are harmful as respirable particles. They also play a role as cloud condensation nuclei and have radiative effects on global climate. A combination of {delta}{sup 18}O-SO{sub 4} data with catchment sulfur mass balances was used to constrain processes affecting S cycling in the atmosphere and spruce forests of the Czech Republic. Extremely high S fluxes via spruce throughfall and runoff were measured at Jezeri (49 and 80 kg S ha{sup -1} yr{sup -1}, respectively). The second catchment, Na Lizu, was 10 times less polluted. In both catchments, {delta}{sup 18}O-SO{sub 4} decreased in the following order: open-area precipitation {gt} throughfall {gt} runoff. The 180-SO{sub 4} values of throughfall exhibited a seasonal pattern at both sites, with maxima in summer and minima in winter. This seasonal pattern paralleled {delta}{sup 18}O-H{sub 2}O values, which were offset by -18{per_thousand}. Sulfate in throughfall was predominantly formed by heterogeneous (aqueous) oxidation of SO{sub 2}. Wet-deposited sulfate in an open area did not show systematic {delta}{sup 18}O-SO{sub 4} trends, suggesting formation by homogeneous (gaseous) oxidation and/or transport from large distances. The percentage of incoming S that is organically cycled in soil was similar under the high and the low pollution. High-temperature {sup 18}O-rich sulfate was not detected, which contrasts with North American industrial sites. 29 refs., 4 figs., 3 tabs.

  14. Fire as an ecosystem process: Chapter 3

    USGS Publications Warehouse

    Keeley, Jon E.; Safford, Hugh D.

    2016-01-01

    This long-anticipated reference and sourcebook for California’s remarkable ecological abundance provides an integrated assessment of each major ecosystem type—its distribution, structure, function, and management. A comprehensive synthesis of our knowledge about this biologically diverse state, Ecosystems of California covers the state from oceans to mountaintops using multiple lenses: past and present, flora and fauna, aquatic and terrestrial, natural and managed. Each chapter evaluates natural processes for a specific ecosystem, describes drivers of change, and discusses how that ecosystem may be altered in the future. This book also explores the drivers of California’s ecological patterns and the history of the state’s various ecosystems, outlining how the challenges of climate change and invasive species and opportunities for regulation and stewardship could potentially affect the state’s ecosystems. The text explicitly incorporates both human impacts and conservation and restoration efforts and shows how ecosystems support human well-being. Edited by two esteemed ecosystem ecologists and with overviews by leading experts on each ecosystem, this definitive work will be indispensable for natural resource management and conservation professionals as well as for undergraduate or graduate students of California’s environment and curious naturalists.

  15. Nutrient recycling affects autotroph and ecosystem stoichiometry.

    PubMed

    Ballantyne, Ford; Menge, Duncan N L; Ostling, Annette; Hosseini, Parviez

    2008-04-01

    Stoichiometric nutrient ratios are the consequence of myriad interacting processes, both biotic and abiotic. Theoretical explanations for autotroph stoichiometry have focused on species' nutrient requirements but have not addressed the role of nutrient availability in determining autotroph stoichiometry. Remineralization of organic N and P supplies a significant fraction of inorganic N and P to autotrophs, making nutrient recycling a potentially important process influencing autotroph stoichiometry. To quantitatively investigate the relationship between available N and P, autotroph N:P, and nutrient recycling, we analyze a stoichiometrically explicit model of autotroph growth, incorporating Michaelis-Menten-Monod nutrient uptake kinetics, Droop growth, and Liebig's law of the minimum. If autotroph growth is limited by a single nutrient, increased recycling of the limiting nutrient pushes autotrophs toward colimitation and alters both autotroph and environmental stoichiometry. We derive a steady state relationship between input stoichiometry, autotroph N:P, and the stoichiometry of organic losses that allows us to estimate the relative recycling of N to P within an ecosystem. We then estimate relative N and P recycling for a marine, an aquatic, and two terrestrial ecosystems. Preferential P recycling, in conjunction with greater relative P retention at the organismal and ecosystem levels, presents a strong case for the importance of P to biomass production across ecosystems.

  16. Biogeochemical Processes in Microbial Ecosystems

    NASA Technical Reports Server (NTRS)

    DesMarais, David J.

    2001-01-01

    The hierarchical organization of microbial ecosystems determines process rates that shape Earth's environment, create the biomarker sedimentary and atmospheric signatures of life, and define the stage upon which major evolutionary events occurred. In order to understand how microorganisms have shaped the global environment of Earth and, potentially, other worlds, we must develop an experimental paradigm that links biogeochemical processes with ever-changing temporal and spatial distributions of microbial populations and their metabolic properties. Additional information is contained in the original extended abstract.

  17. Biogeochemical Processes in Microbial Ecosystems

    NASA Technical Reports Server (NTRS)

    DesMarais, David J.; DeVincenzi, Donald L. (Technical Monitor)

    2001-01-01

    The hierarchical organization of microbial ecosystems determines process rates that shape Earth's environment, create the biomarker sedimentary and atmospheric signatures of life and define the stage upon which major evolutionary events occurred. In order to understand how microorganisms have shaped the global environment of Earth and potentially, other worlds, we must develop an experimental paradigm that links biogeochemical processes with ever-changing temporal and spatial distributions of microbial population, and their metabolic properties. Photosynthetic microbial mats offer an opportunity to define holistic functionality at the millimeter scale. At the same time, their Biogeochemistry contributes to environmental processes on a planetary scale. These mats are possibly direct descendents of the most ancient biological communities; communities in which oxygenic photosynthesis might have been invented. Mats provide one of the best natural systems to study how microbial populations associate to control dynamic biogeochemical gradients. These are self-sustaining, complete ecosystems in which light energy absorbed over a diel (24 hour) cycle drives the synthesis of spatially-organized, diverse biomass. Tightly-coupled microorganisms in the mat have specialized metabolisms that catalyze transformations of carbon, nitrogen. sulfur, and a host of other elements.

  18. Neotropical Amphibian Declines Affect Stream Ecosystem Properties

    NASA Astrophysics Data System (ADS)

    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.

  19. Process-Based Thinking in Ecosystem Education

    ERIC Educational Resources Information Center

    Jordan, Rebecca C.; Gray, Steven A.; Brooks, Wesley R.; Honwad, Sameer; Hmelo-Silver, Cindy E.

    2013-01-01

    Understanding complex systems such as ecosystems is difficult for young K-12 students, and students' representations of ecosystems are often limited to nebulously defined relationships between macro-level structural components inherent to the ecosystem in focus (rainforest, desert, pond, etc.) instead of generalizing processes across ecosystems…

  20. Plant ecology. Anthropogenic environmental changes affect ecosystem stability via biodiversity.

    PubMed

    Hautier, Yann; Tilman, David; Isbell, Forest; Seabloom, Eric W; Borer, Elizabeth T; Reich, Peter B

    2015-04-17

    Human-driven environmental changes may simultaneously affect the biodiversity, productivity, and stability of Earth's ecosystems, but there is no consensus on the causal relationships linking these variables. Data from 12 multiyear experiments that manipulate important anthropogenic drivers, including plant diversity, nitrogen, carbon dioxide, fire, herbivory, and water, show that each driver influences ecosystem productivity. However, the stability of ecosystem productivity is only changed by those drivers that alter biodiversity, with a given decrease in plant species numbers leading to a quantitatively similar decrease in ecosystem stability regardless of which driver caused the biodiversity loss. These results suggest that changes in biodiversity caused by drivers of environmental change may be a major factor determining how global environmental changes affect ecosystem stability.

  1. Linking ecosystem processes to sustainable wetland management

    USGS Publications Warehouse

    Euliss, Ned H.; Smith, Loren M.; Wilcox, Douglas A.; Browne, Bryant A.

    2009-01-01

    As a result of concern over problems associated with the future of managed wetlands in North America, nearly two dozen wetland scientists and managers met in February 2006 at Bosque del Apache National Wildlife Refuge in New Mexico and discussed a sustainable approach to wetland management. This approach links science with management by focusing on underlying wetland processes. From that meeting, several papers were developed and published in Wetlands to address these concerns (Euliss et al. 2008, Smith et al. 2008, Wilcox 2008). This article summarizes our first paper, Euliss et al. (2008), and a future Newsletter article will summarize Smith et al. (2008). Realization of the role that complex interactions play in maintaining ecosystems, coupled with increasing demands of humans for ecosystem services, has prompted much interest in ecosystem management. Not surprisingly, sustainability of ecosystems has become an explicitly stated goal of many natural resource agencies and, in some cases, has been legislatively mandated to ensure provision of resources for future generations. However, examples of sustainable ecosystem management are uncommon because management goals often focus on specific deliverables rather than processes that sustain ecosystems. This paper has three sections: (1) perspectives in which we provide a bit of history, (2), ecological consequences of a static view, and (3) suggestions to aid wetland managers link management goals with critical ecosystem processes responsible for provision of wetland services.

  2. Salvage logging, ecosystem processes, and biodiversity conservation.

    PubMed

    Lindenmayer, D B; Noss, R F

    2006-08-01

    We summarize the documented and potential impacts of salvage logging--a form of logging that removes trees and other biological material from sites after natural disturbance. Such operations may reduce or eliminate biological legacies, modify rare postdisturbance habitats, influence populations, alter community composition, impair natural vegetation recovery, facilitate the colonization of invasive species, alter soil properties and nutrient levels, increase erosion, modify hydrological regimes and aquatic ecosystems, and alter patterns of landscape heterogeneity These impacts can be assigned to three broad and interrelated effects: (1) altered stand structural complexity; (2) altered ecosystem processes and functions; and (3) altered populations of species and community composition. Some impacts may be different from or additional to the effects of traditional logging that is not preceded by a large natural disturbance because the conditions before, during, and after salvage logging may differ from those that characterize traditional timber harvesting. The potential impacts of salvage logging often have been overlooked, partly because the processes of ecosystem recovery after natural disturbance are still poorly understood and partly because potential cumulative effects of natural and human disturbance have not been well documented. Ecologically informed policies regarding salvage logging are needed prior to major natural disturbances so that when they occur ad hoc and crisis-mode decision making can be avoided. These policies should lead to salvage-exemption zones and limits on the amounts of disturbance-derived biological legacies (e.g., burned trees, logs) that are removed where salvage logging takes place. Finally, we believe new terminology is needed. The word salvage implies that something is being saved or recovered, whereas from an ecological perspective this is rarely the case.

  3. Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS)

    NASA Technical Reports Server (NTRS)

    Masek, Jeffrey G.

    2006-01-01

    The Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS) project is creating a record of forest disturbance and regrowth for North America from the Landsat satellite record, in support of the carbon modeling activities. LEDAPS relies on the decadal Landsat GeoCover data set supplemented by dense image time series for selected locations. Imagery is first atmospherically corrected to surface reflectance, and then change detection algorithms are used to extract disturbance area, type, and frequency. Reuse of the MODIS Land processing system (MODAPS) architecture allows rapid throughput of over 2200 MSS, TM, and ETM+ scenes. Initial ("Beta") surface reflectance products are currently available for testing, and initial continental disturbance products will be available by the middle of 2006.

  4. Pressure and Buoyancy in Aquatic Ecosystems. Physical Processes in Terrestrial and Aquatic Ecosystems, Transport Processes.

    ERIC Educational Resources Information Center

    Cowan, Christina E.

    This module is part of a series 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 module explores some of the characteristics of aquatic organisms which can be…

  5. The Atmospheric Signatures of Terrestrial Ecosystem Processes: Results From a Coupled Atmosphere-Ecosystem Model

    NASA Astrophysics Data System (ADS)

    Medvigy, D.; Moorcroft, P. R.

    2003-12-01

    Global-scale analyses of weekly CO2 flask samples have shown that a number of terrestrial regions are significantly affecting the rate at which carbon dioxide is building up in the atmosphere. However, the observations used in these studies come primarily from stations that sample the marine boundary layer in order to eliminate variance due to terrestrial fluxes, making it difficult to identify the processes responsible for the observed patterns of terrestrial CO2 flux. To address this issue, we have developed a regional-scale, coupled atmosphere-ecosystem model capable of assimilating observations from a diverse array of data sources, including eddy-flux measurements of surface CO2 fluxes, measurements of atmospheric CO2 concentrations obtained from aircraft and tall towers, and observations of canopy structure and dynamics obtained from satellite observations and forest inventory data. The model consists of a newly-developed, mass-conserving version of the mesoscale Regional Atmospheric Modeling System model (RAMS) coupled to the Ecosystem Demography Model (ED), which is able to represent the influence of both long-term and short-term processes on patterns of terrestrial CO2 flux. We are using the coupled RAMS-ED model to perform forward and inverse modeling studies of regional carbon budgets within the North American continent. Preliminary results highlight the model's ability to connect regional patterns of atmospheric CO2 to the underlying state of the ecosystems within a region.

  6. Factors Affecting the Tutoring Process.

    ERIC Educational Resources Information Center

    Hartman, Hope J.

    1990-01-01

    Analyzes factors internal to the tutor and tutee (i.e., cognition, metacognition, and affect) and external to them (e.g., teacher/tutor background knowledge, educational environment, content to be learned, socioeconomic status, family background, and cultural forces) that influence the tutoring process. Suggests a theoretical framework for…

  7. Community history affects the predictability of microbial ecosystem development

    PubMed Central

    Pagaling, Eulyn; Strathdee, Fiona; Spears, Bryan M; Cates, Michael E; Allen, Rosalind J; Free, Andrew

    2014-01-01

    Microbial communities mediate crucial biogeochemical, biomedical and biotechnological processes, yet our understanding of their assembly, and our ability to control its outcome, remain poor. Existing evidence presents conflicting views on whether microbial ecosystem assembly is predictable, or inherently unpredictable. We address this issue using a well-controlled laboratory model system, in which source microbial communities colonize a pristine environment to form complex, nutrient-cycling ecosystems. When the source communities colonize a novel environment, final community composition and function (as measured by redox potential) are unpredictable, although a signature of the community's previous history is maintained. However, when the source communities are pre-conditioned to their new habitat, community development is more reproducible. This situation contrasts with some studies of communities of macro-organisms, where strong selection under novel environmental conditions leads to reproducible community structure, whereas communities under weaker selection show more variability. Our results suggest that the microbial rare biosphere may have an important role in the predictability of microbial community development, and that pre-conditioning may help to reduce unpredictability in the design of microbial communities for biotechnological applications. PMID:23985743

  8. Ecosystem carbon storage capacity as affected by disturbance regimes: A general theoretical model

    SciTech Connect

    Weng, Ensheng; Luo, Yiqi; Wang, Weile; Wang, Han; Hayes, Daniel J; McGuire, A. David; Hastings, Alan; Schimel, David

    2012-01-01

    Disturbances have been recognized as a key factor shaping terrestrial ecosystem states and dynamics. A general model that quantitatively describes the relationship between carbon storage and disturbance regime is critical for better understanding large scale terrestrial ecosystem carbon dynamics. We developed a model (REGIME) to quantify ecosystem carbon storage capacities (E[x]) under varying disturbance regimes with an analytical solution E[x] = U {center_dot} {tau}{sub E} {center_dot} {lambda}{lambda} + s {tau} 1, where U is ecosystem carbon influx, {tau}{sub E} is ecosystem carbon residence time, and {tau}{sub 1} is the residence time of the carbon pool affected by disturbances (biomass pool in this study). The disturbance regime is characterized by the mean disturbance interval ({lambda}) and the mean disturbance severity (s). It is a Michaelis-Menten-type equation illustrating the saturation of carbon content with mean disturbance interval. This model analytically integrates the deterministic ecosystem carbon processes with stochastic disturbance events to reveal a general pattern of terrestrial carbon dynamics at large scales. The model allows us to get a sense of the sensitivity of ecosystems to future environmental changes just by a few calculations. According to the REGIME model, for example, approximately 1.8 Pg C will be lost in the high-latitude regions of North America (>45{sup o} N) if fire disturbance intensity increases around 5.7 time the current intensity to the end of the twenty-first century, which will require around 12% increases in net primary productivity (NPP) to maintain stable carbon stocks. If the residence time decreased 10% at the same time additional 12.5% increases in NPP are required to keep current C stocks. The REGIME model also lays the foundation for analytically modeling the interactions between deterministic biogeochemical processes and stochastic disturbance events.

  9. Going underground: root traits as drivers of ecosystem processes.

    PubMed

    Bardgett, Richard D; Mommer, Liesje; De Vries, Franciska T

    2014-12-01

    Ecologists are increasingly adopting trait-based approaches to understand how community change influences ecosystem processes. However, most of this research has focussed on aboveground plant traits, whereas it is becoming clear that root traits are important drivers of many ecosystem processes, such as carbon (C) and nutrient cycling, and the formation and structural stability of soil. Here, we synthesise emerging evidence that illustrates how root traits impact ecosystem processes, and propose a pathway to unravel the complex roles of root traits in driving ecosystem processes and their response to global change. Finally, we identify research challenges and novel technologies to address them. PMID:25459399

  10. Does consideration of water routing affect simulated water and carbon dynamics in terrestrial ecosystems?

    NASA Astrophysics Data System (ADS)

    Tang, G.; Schneiderman, E. M.; Band, L. E.; Hwang, T.; Pierson, D. C.; Pradhanang, S. M.; Zion, M. S.

    2013-10-01

    The cycling of carbon in terrestrial ecosystems is closely coupled with the cycling of water. An important mechanism connecting ecological and hydrological processes in terrestrial ecosystems is lateral flow of water along landscapes. Few studies, however, have examined explicitly how consideration of water routing affects simulated water and carbon dynamics in terrestrial ecosystems. The objective of this study is to explore how consideration of water routing in a process-based hydroecological model affects simulated water and carbon dynamics. To achieve that end, we rasterized the regional hydroecological simulation systems (RHESSys) and employed the rasterized RHESSys (R-RHESSys) in a forested watershed. We performed and compared two contrasting simulations, one with and another without water routing. We found that R-RHESSys is able to correctly simulate major hydrological and ecological variables regardless of whether water routing is considered. When water routing was neglected, however, soil water table depth and saturation deficit were simulated to be smaller and spatially more homogeneous. As a result, evaporation, forest productivity and soil heterotrophic respiration also were simulated to be spatially more homogeneous compared to simulation with water routing. When averaged for the entire watershed, however, differences in simulated water and carbon fluxes are not significant between the two simulations. Overall, the study demonstrated that consideration of water routing enabled R-RHESSys to better capture our preconception of the spatial patterns of water table depth and saturation deficit across the watershed. Because the spatial pattern of soil moisture is fundamental to water efflux from land to the atmosphere, forest productivity and soil microbial activity, ecosystem and carbon cycle models, therefore, need to explicitly represent water routing in order to accurately quantify the magnitudes and patterns of water and carbon fluxes in terrestrial

  11. Mammal population regulation, keystone processes and ecosystem dynamics.

    PubMed Central

    Sinclair, A R E

    2003-01-01

    The theory of regulation in animal populations is fundamental to understanding the dynamics of populations, the causes of mortality and how natural selection shapes the life history of species. In mammals, the great range in body size allows us to see how allometric relationships affect the mode of regulation. Resource limitation is the fundamental cause of regulation. Top-down limitation through predators is determined by four factors: (i). body size; (ii). the diversity of predators and prey in the system; (iii). whether prey are resident or migratory; and (iv). the presence of alternative prey for predators. Body size in mammals has two important consequences. First, mammals, particularly large species, can act as keystones that determine the diversity of an ecosystem. I show how keystone processes can, in principle, be measured using the example of the wildebeest in the Serengeti ecosystem. Second, mammals act as ecological landscapers by altering vegetation succession. Mammals alter physical structure, ecological function and species diversity in most terrestrial biomes. In general, there is a close interaction between allometry, population regulation, life history and ecosystem dynamics. These relationships are relevant to applied aspects of conservation and pest management. PMID:14561329

  12. Biomass is the main driver of changes in ecosystem process rates during tropical forest succession.

    PubMed

    Lohbeck, Madelon; Poorter, Lourens; Martínez-Ramos, Miguel; Bongers, Frans

    2015-05-01

    Over half of the world's forests are disturbed, and the rate at which ecosystem processes recover after disturbance is important for the services these forests can provide. We analyze the drivers' underlying changes in rates of key ecosystem processes (biomass productivity, litter productivity, actual litter decomposition, and potential litter decomposition) during secondary succession after shifting cultivation in wet tropical forest of Mexico. We test the importance of three alternative drivers of ecosystem processes: vegetation biomass (vegetation quantity hypothesis), community-weighted trait mean (mass ratio hypothesis), and functional diversity (niche complementarity hypothesis) using structural equation modeling. This allows us to infer the relative importance of different mechanisms underlying ecosystem process recovery. Ecosystem process rates changed during succession, and the strongest driver was aboveground biomass for each of the processes. Productivity of aboveground stem biomass and leaf litter as well as actual litter decomposition increased with initial standing vegetation biomass, whereas potential litter decomposition decreased with standing biomass. Additionally, biomass productivity was positively affected by community-weighted mean of specific leaf area, and potential decomposition was positively affected by functional divergence, and negatively by community-weighted mean of leaf dry matter content. Our empirical results show that functional diversity and community-weighted means are of secondary importance for explaining changes in ecosystem process rates during tropical forest succession. Instead, simply, the amount of vegetation in a site is the major driver of changes, perhaps because there is a steep biomass buildup during succession that overrides more subtle effects of community functional properties on ecosystem processes. We recommend future studies in the field of biodiversity and ecosystem functioning to separate the effects of

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

    PubMed

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

    2015-01-01

    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. PMID:25766381

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

    PubMed

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  16. Regulation of ecosystem processes by arthropod communities

    SciTech Connect

    Seastedt, T.R.; Crossley, D.A. Jr.

    1983-09-01

    Arthropods or their activities regulate the amounts of forms of mass and nutrients in terrestrial ecosystems. Canopy arthropods have the largest impacts on mobile elements such as potassium, while soil detritivores control mineralization rates of less mobile elements such as nitrogen, phosphorus and calcium. Nominal (base-line) herbivory and detritivory combine to speed nutrient cycling and reduce standing crops of decaying plant materials. 42 references, 1 figure, 3 tables.

  17. Same pattern, different mechanism: Locking onto the role of key species in seafloor ecosystem process

    NASA Astrophysics Data System (ADS)

    Woodin, Sarah Ann; Volkenborn, Nils; Pilditch, Conrad A.; Lohrer, Andrew M.; Wethey, David S.; Hewitt, Judi E.; Thrush, Simon F.

    2016-05-01

    Seafloor biodiversity is a key mediator of ecosystem functioning, but its role is often excluded from global budgets or simplified to black boxes in models. New techniques allow quantification of the behavior of animals living below the sediment surface and assessment of the ecosystem consequences of complex interactions, yielding a better understanding of the role of seafloor animals in affecting key processes like primary productivity. Combining predictions based on natural history, behavior of key benthic species and environmental context allow assessment of differences in functioning and process, even when the measured ecosystem property in different systems is similar. Data from three sedimentary systems in New Zealand illustrate this. Analysis of the behaviors of the infaunal ecosystem engineers in each system revealed three very different mechanisms driving ecosystem function: density and excretion, sediment turnover and surface rugosity, and hydraulic activities and porewater bioadvection. Integrative metrics of ecosystem function in some cases differentiate among the systems (gross primary production) and in others do not (photosynthetic efficiency). Analyses based on behaviors and activities revealed important ecosystem functional differences and can dramatically improve our ability to model the impact of stressors on ecosystem and global processes.

  18. Same pattern, different mechanism: Locking onto the role of key species in seafloor ecosystem process.

    PubMed

    Woodin, Sarah Ann; Volkenborn, Nils; Pilditch, Conrad A; Lohrer, Andrew M; Wethey, David S; Hewitt, Judi E; Thrush, Simon F

    2016-01-01

    Seafloor biodiversity is a key mediator of ecosystem functioning, but its role is often excluded from global budgets or simplified to black boxes in models. New techniques allow quantification of the behavior of animals living below the sediment surface and assessment of the ecosystem consequences of complex interactions, yielding a better understanding of the role of seafloor animals in affecting key processes like primary productivity. Combining predictions based on natural history, behavior of key benthic species and environmental context allow assessment of differences in functioning and process, even when the measured ecosystem property in different systems is similar. Data from three sedimentary systems in New Zealand illustrate this. Analysis of the behaviors of the infaunal ecosystem engineers in each system revealed three very different mechanisms driving ecosystem function: density and excretion, sediment turnover and surface rugosity, and hydraulic activities and porewater bioadvection. Integrative metrics of ecosystem function in some cases differentiate among the systems (gross primary production) and in others do not (photosynthetic efficiency). Analyses based on behaviors and activities revealed important ecosystem functional differences and can dramatically improve our ability to model the impact of stressors on ecosystem and global processes. PMID:27230562

  19. Same pattern, different mechanism: Locking onto the role of key species in seafloor ecosystem process

    PubMed Central

    Woodin, Sarah Ann; Volkenborn, Nils; Pilditch, Conrad A.; Lohrer, Andrew M.; Wethey, David S.; Hewitt, Judi E.; Thrush, Simon F.

    2016-01-01

    Seafloor biodiversity is a key mediator of ecosystem functioning, but its role is often excluded from global budgets or simplified to black boxes in models. New techniques allow quantification of the behavior of animals living below the sediment surface and assessment of the ecosystem consequences of complex interactions, yielding a better understanding of the role of seafloor animals in affecting key processes like primary productivity. Combining predictions based on natural history, behavior of key benthic species and environmental context allow assessment of differences in functioning and process, even when the measured ecosystem property in different systems is similar. Data from three sedimentary systems in New Zealand illustrate this. Analysis of the behaviors of the infaunal ecosystem engineers in each system revealed three very different mechanisms driving ecosystem function: density and excretion, sediment turnover and surface rugosity, and hydraulic activities and porewater bioadvection. Integrative metrics of ecosystem function in some cases differentiate among the systems (gross primary production) and in others do not (photosynthetic efficiency). Analyses based on behaviors and activities revealed important ecosystem functional differences and can dramatically improve our ability to model the impact of stressors on ecosystem and global processes. PMID:27230562

  20. Not all ski slopes are created equal: disturbance intensity affects ecosystem properties.

    PubMed

    Burt, Jennifer W; Rice, Kevin J

    2009-12-01

    In mountain regions around the world, downhill ski areas represent a significant source of anthropogenic disturbance while also providing recreation and revenue. Ski-run creation always results in some level of disturbance, but disturbance intensity varies greatly with construction method. Ski runs may be established either by clearing (cutting and removing tall vegetation) or by clearing and then machine-grading (leveling the soil surface with heavy equipment). To quantify how these different intensities of initial disturbance affect ecosystem properties, we extensively surveyed vegetation, soils, and environmental characteristics on cleared ski runs, graded ski runs, and adjacent reference forests across seven large downhill ski resorts in the northern Sierra Nevada, USA. We found that the greater disturbance intensity associated with grading resulted in greater impacts on all ecosystem properties considered, including plant community composition and diversity, soil characteristics relating to processes of nutrient cycling and retention, and measures of erosion potential. We also found that cleared ski runs retained many ecological similarities to reference forests and might even offer some added benefits by possessing greater plant species and functional diversity than either forests or graded runs. Because grading is more damaging to multiple indicators of ecosystem function, clearing rather than grading should be used to create ski slopes wherever practical.

  1. The importance of plant genotype and contemporary evolution for terrestrial ecosystem processes.

    PubMed

    Fitzpatrick, Connor R; Agrawal, Anurag A; Basiliko, Nathan; Hastings, Amy P; Isaac, Marney E; Preston, Michael; Johnson, Marc T J

    2015-10-01

    Plant genetic variation and evolutionary dynamics are predicted to impact ecosystem processes but these effects are poorly understood. Here we test the hypothesis that plant genotype and contemporary evolution influence the flux of energy and nutrients through soil, which then feedback to affect seedling performance in subsequent generations. We conducted a multiyear field evolution experiment using the native biennial plant Oenothera biennis. This experiment was coupled with experimental assays to address our hypothesis and quantify the relative importance of evolutionary and ecological factors on multiple ecosystem processes. Plant genotype, contemporary evolution, spatial variation, and herbivory affected ecosystem processes (e.g., leaf decay, soil respiration, seedling performance, N cycling), but their relative importance varied between specific ecosystem variables. Insect herbivory and evolution also contributed to a feedback that affected seedling biomass of O. biennis in the next generation. Our results show that heritable variation among plant genotypes can be an important factor affecting local ecosystem processes, and while effects of contemporary evolution were detectable and sometimes strong, they were often contingent on other ecological, factors. PMID:26649385

  2. Toxins in transgenic crop byproducts may affect headwater stream ecosystems.

    PubMed

    Rosi-Marshall, E J; Tank, J L; Royer, T V; Whiles, M R; Evans-White, M; Chambers, C; Griffiths, N A; Pokelsek, J; Stephen, M L

    2007-10-01

    Corn (Zea mays L.) that has been genetically engineered to produce the Cry1Ab protein (Bt corn) is resistant to lepidopteran pests. Bt corn is widely planted in the midwestern United States, often adjacent to headwater streams. We show that corn byproducts, such as pollen and detritus, enter headwater streams and are subject to storage, consumption, and transport to downstream water bodies. Laboratory feeding trials showed that consumption of Bt corn byproducts reduced growth and increased mortality of nontarget stream insects. Stream insects are important prey for aquatic and riparian predators, and widespread planting of Bt crops has unexpected ecosystem-scale consequences. PMID:17923672

  3. Emotional processing affects movement speed.

    PubMed

    Hälbig, Thomas D; Borod, Joan C; Frisina, Pasquale G; Tse, Winona; Voustianiouk, Andrei; Olanow, C Warren; Gracies, Jean-Michel

    2011-09-01

    Emotions can affect various aspects of human behavior. The impact of emotions on behavior is traditionally thought to occur at central, cognitive and motor preparation stages. Using EMG to measure the effects of emotion on movement, we found that emotional stimuli differing in valence and arousal elicited highly specific effects on peripheral movement time. This result has conceptual implications for the emotion-motion link and potentially practical implications for neurorehabilitation and professional environments where fast motor reactions are critical.

  4. Process-based Principles for Restoring Dynamic River Ecosystems

    NASA Astrophysics Data System (ADS)

    Pess, G. R.; Beechie, T. J.; Pollock, M. M.

    2006-12-01

    Process-based restoration focuses on re-establishing natural rates and magnitudes of geomorphological, hydrological, and biological processes that sustain biodiversity and biological productivity in dynamic river ecosystems. It contrasts with traditional restoration practices, which focus on creating specific habitat characteristics that meet perceived "good" or "minimum" habitat conditions or standards. Process-based restoration relies on the understanding that habitat-forming processes are dynamic and comprise a shifting mosaic of diverse habitats. Local animal populations or communities are adapted to this dynamic habitat mosaic. Fundamental principles underlying process-based restoration are: (1) restoration must address biophysical processes that drive ecosystem change, and (2) the scale of restoration must be relevant to the appropriate landscape and biological process scales. Restoration efforts that re-establish natural rates and magnitudes of system processes promote ecosystem recovery, and help avoid common pitfalls of traditional restoration practices such as creating habitats that are outside the range of a site's natural potential, fixing habitats in space and time, and building habitats that are ultimately overwhelmed by untreated or uncontrollable system drivers. Restoring such processes also allows dynamic riverine ecosystems to express their natural potential, which generates the natural range of habitat conditions to which biological communities are adapted. Non-point processes such as erosion often require restoration at the scale of watersheds to effectively restore river ecosystems, whereas reach-level processes such as the maintenance of connected floodplain habitats can be effective at smaller spatial scales. Flow restoration in regulated rivers should consider the full range of environmentally important flows (e.g., low flow to floods). Biological processes such as the life-history scales of migratory animals (e.g., anadromous salmon) may be

  5. Local adaptation in Trinidadian guppies alters ecosystem processes.

    PubMed

    Bassar, Ronald D; Marshall, Michael C; López-Sepulcre, Andrés; Zandonà, Eugenia; Auer, Sonya K; Travis, Joseph; Pringle, Catherine M; Flecker, Alexander S; Thomas, Steven A; Fraser, Douglas F; Reznick, David N

    2010-02-23

    Theory suggests evolutionary change can significantly influence and act in tandem with ecological forces via ecological-evolutionary feedbacks. This theory assumes that significant evolutionary change occurs over ecologically relevant timescales and that phenotypes have differential effects on the environment. Here we test the hypothesis that local adaptation causes ecosystem structure and function to diverge. We demonstrate that populations of Trinidadian guppies (Poecilia reticulata), characterized by differences in phenotypic and population-level traits, differ in their impact on ecosystem properties. We report results from a replicated, common garden mesocosm experiment and show that differences between guppy phenotypes result in the divergence of ecosystem structure (algal, invertebrate, and detrital standing stocks) and function (gross primary productivity, leaf decomposition rates, and nutrient flux). These phenotypic effects are further modified by effects of guppy density. We evaluated the generality of these effects by replicating the experiment using guppies derived from two independent origins of the phenotype. Finally, we tested the ability of multiple guppy traits to explain observed differences in the mesocosms. Our findings demonstrate that evolution can significantly affect both ecosystem structure and function. The ecosystem differences reported here are consistent with patterns observed across natural streams and argue that guppies play a significant role in shaping these ecosystems. PMID:20133670

  6. The First Law of Thermodynamics for Ecosystems. Physical Processes in Terrestrial and Aquatic Ecosystems, Thermodynamics.

    ERIC Educational Resources Information Center

    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 module and a comparison module are concerned with elementary concepts of thermodynamics as…

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

    PubMed

    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.

  8. Nitrogen Additions Affect Root Dynamics in a Boreal Forest Ecosystem

    NASA Astrophysics Data System (ADS)

    Turner, K. M.; Treseder, K. K.

    2004-12-01

    As with many ecosystems, North American boreal forests are increasingly subjected to anthropogenic nitrogen deposition. To examine potential effects on plant growth, we created nitrogen fertilization plots in three sites along an Alaskan fire chronosequence composed of forests aged 5, 17, and 80 years. Each site had been exposed to two years of nitrogen fertilization, with four control plots and four nitrogen plots per site. General observations indicate that aboveground net primary productivity appears to be nitrogen limited in each site. We hypothesized that nitrogen fertilization would positively influence root dynamics as well, with nitrogen additions resulting in an increase in standing root biomass and length. To test our hypothesis, we used a minirhizotron camera to collect sequential images of roots in the top 10 cm of soil in both nitrogen fertilized and control plots in each site. Images were collected monthly during the growing season, with a total of five sampling times between May 2003 and May 2004. We then analyzed the images with WinRhizotron root measurement software. Nitrogen fertilization had varying effects on root biomass among the three sites, with a significant site by N interaction (P = 0.039). A decrease in root biomass was observed in the 5 and 80 year old sites, dropping from 207 g/m2 to 79 g/m2 and from 230 g/m2 to 129 g/m2 for the youngest and oldest sites, respectively. In contrast, root biomass increased from 52 g/m2 to 107 g/m2 in the 17 year old site. (Values are for the top 10 cm of soil only, and likely underestimate total root stocks.) Patterns in standing root lengths diverged from those of root biomass, with a 2.5-fold overall increase under nitrogen fertilization across all sites (P = 0.004). There were no significant differences among sites in nitrogen response. Standing root biomass and length differed from one another in their responses to nitrogen fertilization because nitrogen additions decreased specific root weight (as g

  9. Microbes as Engines of Ecosystem Function: When Does Community Structure Enhance Predictions of Ecosystem Processes?

    PubMed

    Graham, Emily B; Knelman, Joseph E; Schindlbacher, Andreas; Siciliano, Steven; Breulmann, Marc; Yannarell, Anthony; Beman, J M; Abell, Guy; Philippot, Laurent; Prosser, James; Foulquier, Arnaud; Yuste, Jorge C; Glanville, Helen C; Jones, Davey L; Angel, Roey; Salminen, Janne; Newton, Ryan J; Bürgmann, Helmut; Ingram, Lachlan J; Hamer, Ute; Siljanen, Henri M P; Peltoniemi, Krista; Potthast, Karin; Bañeras, Lluís; Hartmann, Martin; Banerjee, Samiran; Yu, Ri-Qing; Nogaro, Geraldine; Richter, Andreas; Koranda, Marianne; Castle, Sarah C; Goberna, Marta; Song, Bongkeun; Chatterjee, Amitava; Nunes, Olga C; Lopes, Ana R; Cao, Yiping; Kaisermann, Aurore; Hallin, Sara; Strickland, Michael S; Garcia-Pausas, Jordi; Barba, Josep; Kang, Hojeong; Isobe, Kazuo; Papaspyrou, Sokratis; Pastorelli, Roberta; Lagomarsino, Alessandra; Lindström, Eva S; Basiliko, Nathan; Nemergut, Diana R

    2016-01-01

    Microorganisms are vital in mediating the earth's biogeochemical cycles; yet, despite our rapidly increasing ability to explore complex environmental microbial communities, the relationship between microbial community structure and ecosystem processes remains poorly understood. Here, we address a fundamental and unanswered question in microbial ecology: 'When do we need to understand microbial community structure to accurately predict function?' We present a statistical analysis investigating the value of environmental data and microbial community structure independently and in combination for explaining rates of carbon and nitrogen cycling processes within 82 global datasets. Environmental variables were the strongest predictors of process rates but left 44% of variation unexplained on average, suggesting the potential for microbial data to increase model accuracy. Although only 29% of our datasets were significantly improved by adding information on microbial community structure, we observed improvement in models of processes mediated by narrow phylogenetic guilds via functional gene data, and conversely, improvement in models of facultative microbial processes via community diversity metrics. Our results also suggest that microbial diversity can strengthen predictions of respiration rates beyond microbial biomass parameters, as 53% of models were improved by incorporating both sets of predictors compared to 35% by microbial biomass alone. Our analysis represents the first comprehensive analysis of research examining links between microbial community structure and ecosystem function. Taken together, our results indicate that a greater understanding of microbial communities informed by ecological principles may enhance our ability to predict ecosystem process rates relative to assessments based on environmental variables and microbial physiology. PMID:26941732

  10. Microbes as Engines of Ecosystem Function: When Does Community Structure Enhance Predictions of Ecosystem Processes?

    PubMed

    Graham, Emily B; Knelman, Joseph E; Schindlbacher, Andreas; Siciliano, Steven; Breulmann, Marc; Yannarell, Anthony; Beman, J M; Abell, Guy; Philippot, Laurent; Prosser, James; Foulquier, Arnaud; Yuste, Jorge C; Glanville, Helen C; Jones, Davey L; Angel, Roey; Salminen, Janne; Newton, Ryan J; Bürgmann, Helmut; Ingram, Lachlan J; Hamer, Ute; Siljanen, Henri M P; Peltoniemi, Krista; Potthast, Karin; Bañeras, Lluís; Hartmann, Martin; Banerjee, Samiran; Yu, Ri-Qing; Nogaro, Geraldine; Richter, Andreas; Koranda, Marianne; Castle, Sarah C; Goberna, Marta; Song, Bongkeun; Chatterjee, Amitava; Nunes, Olga C; Lopes, Ana R; Cao, Yiping; Kaisermann, Aurore; Hallin, Sara; Strickland, Michael S; Garcia-Pausas, Jordi; Barba, Josep; Kang, Hojeong; Isobe, Kazuo; Papaspyrou, Sokratis; Pastorelli, Roberta; Lagomarsino, Alessandra; Lindström, Eva S; Basiliko, Nathan; Nemergut, Diana R

    2016-01-01

    Microorganisms are vital in mediating the earth's biogeochemical cycles; yet, despite our rapidly increasing ability to explore complex environmental microbial communities, the relationship between microbial community structure and ecosystem processes remains poorly understood. Here, we address a fundamental and unanswered question in microbial ecology: 'When do we need to understand microbial community structure to accurately predict function?' We present a statistical analysis investigating the value of environmental data and microbial community structure independently and in combination for explaining rates of carbon and nitrogen cycling processes within 82 global datasets. Environmental variables were the strongest predictors of process rates but left 44% of variation unexplained on average, suggesting the potential for microbial data to increase model accuracy. Although only 29% of our datasets were significantly improved by adding information on microbial community structure, we observed improvement in models of processes mediated by narrow phylogenetic guilds via functional gene data, and conversely, improvement in models of facultative microbial processes via community diversity metrics. Our results also suggest that microbial diversity can strengthen predictions of respiration rates beyond microbial biomass parameters, as 53% of models were improved by incorporating both sets of predictors compared to 35% by microbial biomass alone. Our analysis represents the first comprehensive analysis of research examining links between microbial community structure and ecosystem function. Taken together, our results indicate that a greater understanding of microbial communities informed by ecological principles may enhance our ability to predict ecosystem process rates relative to assessments based on environmental variables and microbial physiology.

  11. Affect, Behavioural Schemas and the Proving Process

    ERIC Educational Resources Information Center

    Selden, Annie; McKee, Kerry; Selden, John

    2010-01-01

    In this largely theoretical article, we discuss the relation between a kind of affect, behavioural schemas and aspects of the proving process. We begin with affect as described in the mathematics education literature, but soon narrow our focus to a particular kind of affect--nonemotional cognitive feelings. We then mention the position of feelings…

  12. Can plant phloem properties affect the link between ecosystem assimilation and respiration?

    NASA Astrophysics Data System (ADS)

    Mencuccini, M.; Hölttä, T.; Sevanto, S.; Nikinmaa, E.

    2012-04-01

    Phloem transport of carbohydrates in plants under field conditions is currently not well understood. This is largely the result of the lack of techniques suitable for measuring phloem physiological properties continuously under field conditions. This lack of knowledge is currently hampering our efforts to link ecosystem-level processes of carbon fixation, allocation and use, especially belowground. On theoretical grounds, the properties of the transport pathway from canopy to roots must be important in affecting the link between carbon assimilation and respiration, but it is unclear whether their effect is partially or entirely masked by processes occurring in other parts of the ecosystem. One can also predict the characteristic time scales over which these effects should occur and, as consequence, predict whether the transfer of turgor and osmotic signals from the site of carbon assimilation to the sites of carbon use are likely to control respiration. We will present two sources of evidence suggesting that the properties of the phloem transport system may affect processes that are dependent on the supply of carbon substrate, such as root or soil respiration. Firstly, we will summarize the results of a literature survey on soil and ecosystem respiration where the speed of transfer of photosynthetic sugars from the plant canopy to the soil surface was determined. Estimates of the transfer speed could be grouped according to whether the study employed isotopic or canopy soil flux-based techniques. These two groups provided very different estimates of transfer times likely because transport of sucrose molecules, and pressure-concentration waves, in phloem differed. Secondly, we will argue that simultaneous measurements of bark and xylem diameters provide a novel tool to determine the continuous variations of phloem turgor in vivo in the field. We will present a model that interprets these changes in xylem and live bark diameters and present data testing the model

  13. Nutrient Enrichment and Food Web Composition Affect Ecosystem Metabolism in an Experimental Seagrass Habitat

    PubMed Central

    Spivak, Amanda C.; Canuel, Elizabeth A.; Duffy, J. Emmett; Richardson, J. Paul

    2009-01-01

    Background Food web composition and resource levels can influence ecosystem properties such as productivity and elemental cycles. In particular, herbivores occupy a central place in food webs as the species richness and composition of this trophic level may simultaneously influence the transmission of resource and predator effects to higher and lower trophic levels, respectively. Yet, these interactions are poorly understood. Methodology/Principal Findings Using an experimental seagrass mesocosm system, we factorially manipulated water column nutrient concentrations, food chain length, and diversity of crustacean grazers to address two questions: (1) Does food web composition modulate the effects of nutrient enrichment on plant and grazer biomasses and stoichiometry? (2) Do ecosystem fluxes of dissolved oxygen and nutrients more closely reflect above-ground biomass and community structure or sediment processes? Nutrient enrichment and grazer presence generally had strong effects on biomass accumulation, stoichiometry, and ecosystem fluxes, whereas predator effects were weaker or absent. Nutrient enrichment had little effect on producer biomass or net ecosystem production but strongly increased seagrass nutrient content, ecosystem flux rates, and grazer secondary production, suggesting that enhanced production was efficiently transferred from producers to herbivores. Gross ecosystem production (oxygen evolution) correlated positively with above-ground plant biomass, whereas inorganic nutrient fluxes were unrelated to plant or grazer biomasses, suggesting dominance by sediment microbial processes. Finally, grazer richness significantly stabilized ecosystem processes, as predators decreased ecosystem production and respiration only in the zero- and one- species grazer treatments. Conclusions/Significance Overall, our results indicate that consumer presence and species composition strongly influence ecosystem responses to nutrient enrichment, and that increasing

  14. Forest Ecosystem Processes at the Watershed Scale: Ecosystem services, feedback and evolution in developing mountainous catchments

    NASA Astrophysics Data System (ADS)

    Band, Larry

    2010-05-01

    significant increase in population in the Southern Appalachians, with new building of second homes in steep headwaters, requiring significant expansion in high altitude roads, in contrast with traditional valley bottom development. With additional increases in hydrologic extremes (heavy precipitation and drought), and progressive changes in forest composition there has been increases in hazard from flash flooding, landslide activity and degraded water quality. The evaluation of integrated watershed impacts of the expected changes in climate and land management requires an interdisciplinary approach including direct feedbacks between ecological, hydrological, geomorphic and atmospheric processes within the framework of an adapting social system. Advances in this type of interdisciplinary research require a network of ecohydrologic observatories generating long term, multi-dimensional data, and a science community working across the interface of multiple fields. Adding individual and institutional behavior as an input or interactive component of watershed ecosystems remains a challenge that spans ecological, hydrological and social science.

  15. Turbulence and Fluid Flow: Perspectives. Physical Processes in Terrestrial and Aquatic Ecosystems, Transport Processes.

    ERIC Educational Resources Information Center

    Simpson, James R.

    This module is part of a series on Physical Processes in Terrestrial and Aquatic Ecosystems. The 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.…

  16. Thermodynamics of Irreversible Processes. Physical Processes in Terrestrial and Aquatic Ecosystems, Transport Processes.

    ERIC Educational Resources Information Center

    Levin, Michael; Gallucci, V. F.

    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 module describes the application of irreversible thermodynamics to biology. It begins with…

  17. Physical processes mediating climate impacts in shelf sea ecosystems

    NASA Astrophysics Data System (ADS)

    Holt, Jason; Schrum, Corinna; Cannaby, Heather; Allen, Icarus; Artioli, Yuri; Butenschon, Momme; Daewel, Ute; Fach, Bettina; Pushpadas, Dhanya; Salihoglu, Baris; Wakelin, Sarah

    2013-04-01

    How global scale climate change might impact coastal and shelf seas is far from straightforward. A myriad of physical processes can potentially act as vectors transferring the larger scale oceanic and atmospheric variability and change to shelf sea physics, biogeochemistry and lower trophic level ecosystems. These act on a wide range of time scales, being strongly dependent on the prevailing conditions of an individual shelf sea basin. Examples of the physical processes include upper ocean warming, seasonal/permanent stratification, wind mixing, convective mixing, light climate, terrestrial input, circulation and ocean-shelf exchange. These potentially impact ecosystem processes such as primary production, plankton community structured, bloom timing, and mid-water production. However, different processes often act in a different sense and are not necessarily additive, leading to damping or amplification effects. During the MEECE project (www.meece.eu) we conducted a series of coordinated downscaled coupled physics-ecosystem model experiments to explore these issues. Here, we review the prevailing physical processes, contrasting five very different shelf sea regions: North Sea, Celtic seas, Baltic Sea, Black sea and Barents Sea, using results from three different model systems: POLCOMS-ERSEM, ECOSMO, BIMS-ECO. Using this ensemble of simulations, along with process sensitivity studies and multiple forcing studies, we are able to identify which physical processes are important in which region, and how they interact. This builds up a picture of contrasting vulnerability of these regions to different vectors of change.

  18. Geologic processes influence the effects of mining on aquatic ecosystems

    USGS Publications Warehouse

    Schmidt, Travis S.; Clements, William H.; Wanty, Richard B.; Verplanck, Philip L.; Church, Stanley E.; San Juan, Carma A.; Fey, David L.; Rockwell, Barnaby W.; DeWitt, Ed H.; Klein, Terry L.

    2012-01-01

    Geologic processes strongly influence water and sediment quality in aquatic ecosystems but rarely are geologic principles incorporated into routine biomonitoring studies. We test if elevated concentrations of metals in water and sediment are restricted to streams downstream of mines or areas that may discharge mine wastes. We surveyed 198 catchments classified as “historically mined” or “unmined,” and based on mineral-deposit criteria, to determine whether water and sediment quality were influenced by naturally occurring mineralized rock, by historical mining, or by a combination of both. By accounting for different geologic sources of metals to the environment, we were able to distinguish aquatic ecosystems limited by metals derived from natural processes from those due to mining. Elevated concentrations of metals in water and sediment were not restricted to mined catchments; depauperate aquatic communities were found in unmined catchments. The type and intensity of hydrothermal alteration and the mineral deposit type were important determinants of water and sediment quality as well as the aquatic community in both mined and unmined catchments. This study distinguished the effects of different rock types and geologic sources of metals on ecosystems by incorporating basic geologic processes into reference and baseline site selection, resulting in a refined assessment. Our results indicate that biomonitoring studies should account for natural sources of metals in some geologic environments as contributors to the effect of mines on aquatic ecosystems, recognizing that in mining-impacted drainages there may have been high pre-mining background metal concentrations.

  19. Geologic processes influence the effects of mining on aquatic ecosystems.

    PubMed

    Schmidt, Travis S; Clements, William H; Wanty, Richard B; Verplanck, Philip L; Church, Stanley E; San Juan, Carma A; Fey, David L; Rockwell, Barnaby W; DeWitt, Ed H; Klein, Terry L

    2012-04-01

    Geologic processes strongly influence water and sediment quality in aquatic ecosystems but rarely are geologic principles incorporated into routine biomonitoring studies. We test if elevated concentrations of metals in water and sediment are restricted to streams downstream of mines or areas that may discharge mine wastes. We surveyed 198 catchments classified as "historically mined" or "unmined," and based on mineral-deposit criteria, to determine whether water and sediment quality were influenced by naturally occurring mineralized rock, by historical mining, or by a combination of both. By accounting for different geologic sources of metals to the environment, we were able to distinguish aquatic ecosystems limited by metals derived from natural processes from those due to mining. Elevated concentrations of metals in water and sediment were not restricted to mined catchments; depauperate aquatic communities were found in unmined catchments. The type and intensity of hydrothermal alteration and the mineral deposit type were important determinants of water and sediment quality as well as the aquatic community in both mined and unmined catchments. This study distinguished the effects of different rock types and geologic sources of metals on ecosystems by incorporating basic geologic processes into reference and baseline site selection, resulting in a refined assessment. Our results indicate that biomonitoring studies should account for natural sources of metals in some geologic environments as contributors to the effect of mines on aquatic ecosystems, recognizing that in mining-impacted drainages there may have been high pre-mining background metal concentrations. PMID:22645817

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

    PubMed

    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.

  1. Multiple dimensions of biodiversity and ecosystem processes: Exploring the joint influence of intraspecific, specific and interspecific diversity.

    PubMed

    Eduardo, Anderson A

    2016-09-01

    The positive influence of biodiversity on ecosystem processes was the focus of intense debate in ecology throughout the recent decades, becoming accepted and treated as a new paradigm in contemporary ecology. However, the available literature in this research field extensively explores species richness as an unidimensional measure for biodiversity. The present study explores how different components of biological diversity (number of genotypes, species, and functional groups) can influence an ecosystem process (biomass fixation). A mathematical model was employed and the simulation results showed that species richness per se does not affect the ecosystem productivity. Genotypic richness affected positively the ecosystem, but only if the genotypes are functionally complementary. The functional groups richness always affected positively the simulated ecosystem process. When together, richness at the different components of biological diversity showed stronger effect on ecosystem, and the scenarios with high species, genotypes and functional groups richness were the most productive ones. The results also allowed to observe that the ecosystems which are diverse in terms of functional groups and genotypes can be less susceptible to species loss. Finally, it is argued that a multiple dimension approach to biodiversity is relevant to advance the current knowledge on the relation between biodiversity and ecosystem functioning.

  2. Biotic Processes Regulating the Carbon Balance of Desert Ecosystems

    SciTech Connect

    R. S. Nowak; J. Arnone; L. Fenstermaker; and S. D. Smith

    2005-07-26

    This project provided the funding to operate and maintain the Nevada Desert FACE Facility. This support funds the CO{sub 2}, system repairs and maintenance, basic physical and biological site information, and personnel that are essential for the experiment to continue. They have continued to assess the effects of elevated CO{sub 2} on three key processes: (1) leaf- to plant-level responses of desert vegetation to elevated atmospheric CO{sub 2}; (2) ecosystem-level responses; and (3) integration of plant and ecosystem processes to understand carbon balance of deserts. The focus is the seminal interactions among atmospheric CO{sub 2}, water, and nitrogen that drive desert responses to elevated CO{sub 2} and explicitly address processes that occur across scales (biological, spatial, and temporal).

  3. Plant Species and Functional Group Combinations Affect Green Roof Ecosystem Functions

    PubMed Central

    Lundholm, Jeremy; MacIvor, J. Scott; MacDougall, Zachary; Ranalli, Melissa

    2010-01-01

    Background 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. Methodology/Principal Findings 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. Conclusions/Significance 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

  4. Microbes as Engines of Ecosystem Function: When Does Community Structure Enhance Predictions of Ecosystem Processes?

    PubMed Central

    Graham, Emily B.; Knelman, Joseph E.; Schindlbacher, Andreas; Siciliano, Steven; Breulmann, Marc; Yannarell, Anthony; Beman, J. M.; Abell, Guy; Philippot, Laurent; Prosser, James; Foulquier, Arnaud; Yuste, Jorge C.; Glanville, Helen C.; Jones, Davey L.; Angel, Roey; Salminen, Janne; Newton, Ryan J.; Bürgmann, Helmut; Ingram, Lachlan J.; Hamer, Ute; Siljanen, Henri M. P.; Peltoniemi, Krista; Potthast, Karin; Bañeras, Lluís; Hartmann, Martin; Banerjee, Samiran; Yu, Ri-Qing; Nogaro, Geraldine; Richter, Andreas; Koranda, Marianne; Castle, Sarah C.; Goberna, Marta; Song, Bongkeun; Chatterjee, Amitava; Nunes, Olga C.; Lopes, Ana R.; Cao, Yiping; Kaisermann, Aurore; Hallin, Sara; Strickland, Michael S.; Garcia-Pausas, Jordi; Barba, Josep; Kang, Hojeong; Isobe, Kazuo; Papaspyrou, Sokratis; Pastorelli, Roberta; Lagomarsino, Alessandra; Lindström, Eva S.; Basiliko, Nathan; Nemergut, Diana R.

    2016-01-01

    Microorganisms are vital in mediating the earth’s biogeochemical cycles; yet, despite our rapidly increasing ability to explore complex environmental microbial communities, the relationship between microbial community structure and ecosystem processes remains poorly understood. Here, we address a fundamental and unanswered question in microbial ecology: ‘When do we need to understand microbial community structure to accurately predict function?’ We present a statistical analysis investigating the value of environmental data and microbial community structure independently and in combination for explaining rates of carbon and nitrogen cycling processes within 82 global datasets. Environmental variables were the strongest predictors of process rates but left 44% of variation unexplained on average, suggesting the potential for microbial data to increase model accuracy. Although only 29% of our datasets were significantly improved by adding information on microbial community structure, we observed improvement in models of processes mediated by narrow phylogenetic guilds via functional gene data, and conversely, improvement in models of facultative microbial processes via community diversity metrics. Our results also suggest that microbial diversity can strengthen predictions of respiration rates beyond microbial biomass parameters, as 53% of models were improved by incorporating both sets of predictors compared to 35% by microbial biomass alone. Our analysis represents the first comprehensive analysis of research examining links between microbial community structure and ecosystem function. Taken together, our results indicate that a greater understanding of microbial communities informed by ecological principles may enhance our ability to predict ecosystem process rates relative to assessments based on environmental variables and microbial physiology. PMID:26941732

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

    PubMed

    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

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

    PubMed

    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

  7. Roles of benthic algae in the structure, function, and assessment of stream ecosystems affected by acid mine drainage.

    PubMed

    Smucker, Nathan J; Drerup, Samuel A; Vis, Morgan L

    2014-06-01

    Tens of thousands of stream kilometers worldwide are degraded by a legacy of acid loads, high metal concentrations, and altered habitat caused by acid mine drainage (AMD) from abandoned underground and surface mines. As the primary production base in streams, the condition of algal-dominated periphyton communities is particularly important to nutrient cycling, energy flow, and higher trophic levels. Here, we synthesize current knowledge regarding how AMD-associated stressors affect (i) algal communities and their use as ecological indicators, (ii) their functional roles in stream ecosystems, and (iii) how these findings inform management decisions and evaluation of restoration effectiveness. A growing body of research has found ecosystem simplification caused by AMD stressors. Species diversity declines, productivity decreases, and less efficient nutrient uptake and retention occur as AMD severity increases. New monitoring approaches, indices of biological condition, and attributes of algal community structure and function effectively assess AMD severity and effectiveness of management practices. Measures of ecosystem processes, such as nutrient uptake rates, extracellular enzyme activities, and metabolism, are increasingly being used as assessment tools, but remain in their infancy relative to traditional community structure-based approaches. The continued development, testing, and implementation of functional measures and their use alongside community structure metrics will further advance assessments, inform management decisions, and foster progress toward restoration goals. Algal assessments will have important roles in making progress toward improving and sustaining the water quality, ecological condition, and ecosystem services of streams in regions affected by the legacy of unregulated coal mining. PMID:26988317

  8. Microbes as engines of ecosystem function: When does community structure enhance predictions of ecosystem processes?

    DOE PAGES

    Graham, Emily B.; Knelman, Joseph E.; Schindlbacher, Andreas; Siciliano, Steven; Breulmann, Marc; Yannarell, Anthony; Beman, J. M.; Abell, Guy; Philippot, Laurent; Prosser, James; et al

    2016-02-24

    In this study, microorganisms are vital in mediating the earth’s biogeochemical cycles; yet, despite our rapidly increasing ability to explore complex environmental microbial communities, the relationship between microbial community structure and ecosystem processes remains poorly understood. Here, we address a fundamental and unanswered question in microbial ecology: ‘When do we need to understand microbial community structure to accurately predict function?’ We present a statistical analysis investigating the value of environmental data and microbial community structure independently and in combination for explaining rates of carbon and nitrogen cycling processes within 82 global datasets. Environmental variables were the strongest predictors of processmore » rates but left 44% of variation unexplained on average, suggesting the potential for microbial data to increase model accuracy. Although only 29% of our datasets were significantly improved by adding information on microbial community structure, we observed improvement in models of processes mediated by narrow phylogenetic guilds via functional gene data, and conversely, improvement in models of facultative microbial processes via community diversity metrics. Our results also suggest that microbial diversity can strengthen predictions of respiration rates beyond microbial biomass parameters, as 53% of models were improved by incorporating both sets of predictors compared to 35% by microbial biomass alone. Our analysis represents the first comprehensive analysis of research examining links between microbial community structure and ecosystem function. Taken together, our results indicate that a greater understanding of microbial communities informed by ecological principles may enhance our ability to predict ecosystem process rates relative to assessments based on environmental variables and microbial physiology.« less

  9. How does vineyard management intensity affect ecosystem services and disservices - insights from a meta-analysis

    NASA Astrophysics Data System (ADS)

    Winter, Silvia; Zaller, Johann G.; Kratschmer, Sophie; Pachinger, Bärbel; Strauss, Peter; Bauer, Thomas; Paredes, Daniel; Gómez, José A.; Guzmán, Gema; Landa, Blanca; Nicolai, Annegret; Burel, Francoise; Cluzeau, Daniel; Popescu, Daniela; Bunea, Claudiu-Ioan; Potthoff, Martin; Guernion, Muriel; Batáry, Péter

    2016-04-01

    Viticultural agro-ecosystems provide a range of different ecosystem services which are affected by management decisions of winegrowers. At the global scale, vineyards are often high intensity agricultural systems with bare soil or inter-row vegetation consisting of only a few plant species. These systems primarily aim at optimizing wine production by reducing competition for water and nutrients between grapevines and weeds and by preventing the outbreak of pests and diseases. At the same time, this kind of management is often associated with ecosystem disservices such as high rates of soil erosion, degradation of soil structure and fertility, contamination of groundwater and decline of biodiversity. Recently, several initiatives across the world tried to overcome detrimental effects of that management style by creating biodiversity friendly vineyards. The consequences of establishing divers cover crop mixes or tolerating spontaneous vegetation in vineyards for ecosystem services (including yield) overstretching local case studies has not been investigated yet. This meta-analysis will provide an overview of all published studies comparing the effects of different vineyard management practices on a range of different ecosystem services like biodiversity, pest control, pollination, soil conservation and carbon sequestration. The aggregated effect size will point out which management measures can provide the best overall net sum of ecosystem services. This meta-analysis is part of the transdisciplinary BiodivERsA project VineDivers and will ultimately lead into management and policy recommendations for various stakeholder groups engaged in viticulture.

  10. Biological Production in Lakes. Physical Processes in Terrestrial and Aquatic Ecosystems, Ecological Processes.

    ERIC Educational Resources Information Center

    Walters, R. A.; Carey, G. F.

    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. Primary production in aquatic ecosystems is carried out by phytoplankton, microscopic plants…

  11. Scaling and predicting solute transport processes in riverine ecosystems

    NASA Astrophysics Data System (ADS)

    Gonzalez-Pinzon, R.; Haggerty, R.; Camacho Botero, L. A.

    2012-12-01

    In the last three decades, research on solute transport and nutrient processing has revealed complex interactions between landscapes and stream ecosystems, and numerous attempts to scale and predict these processes have been primarily limited by the difficulty of measuring and extrapolating hydrodynamic and geomorphic characteristics. We hypothesize that there should be predictable patterns in the way that streams interact with their landscapes, because those interactions are in the form of energy, mass and momentum, which are conservative and interrelated properties. Therefore, despite local hydrogeomorphic characteristics define the actual extent of solute transport processes in a given riverine ecosystem, the physical imprints marked-up in breakthrough curves (BTCs) should have scaling properties. To evaluate our hypothesis we created an extensive database that includes 133 BTCs from conservative tracer experiments conducted under different hydrologic conditions (1 lt/s to 1197 m3/s), different experimental conditions (10s of meters to 10s of kilometers), different geographic positions (South and North America, Europe, Australia, Antarctica), and different types of lotic environments, i.e., urban manmade channels, forested headwater streams, desert-like streams, hyporheic wells, and major rivers. We investigated the existence of patterns in conservative solute transport using a model-independent approach, i.e., temporal moments of the histories of tracer experiments. Our results show that the normalized first absolute moment is correlated with the second and third moments with R2>0.99 for all riverine ecosystems. Most importantly, the first central temporal moment of the distributions (mean travel time) is correlated with the second (variance) with an R2>0.93, and the correlation between the second central moment and the third central moment (skewness) takes the form of the coefficient of skewness (CSK) with an R2>0.98, defining a statistically averaged CSK= 1

  12. Affective processing in bilingual speakers: disembodied cognition?

    PubMed

    Pavlenko, Aneta

    2012-01-01

    A recent study by Keysar, Hayakawa, and An (2012) suggests that "thinking in a foreign language" may reduce decision biases because a foreign language provides a greater emotional distance than a native tongue. The possibility of such "disembodied" cognition is of great interest for theories of affect and cognition and for many other areas of psychological theory and practice, from clinical and forensic psychology to marketing, but first this claim needs to be properly evaluated. The purpose of this review is to examine the findings of clinical, introspective, cognitive, psychophysiological, and neuroimaging studies of affective processing in bilingual speakers in order to identify converging patterns of results, to evaluate the claim about "disembodied cognition," and to outline directions for future inquiry. The findings to date reveal two interrelated processing effects. First-language (L1) advantage refers to increased automaticity of affective processing in the L1 and heightened electrodermal reactivity to L1 emotion-laden words. Second-language (L2) advantage refers to decreased automaticity of affective processing in the L2, which reduces interference effects and lowers electrodermal reactivity to negative emotional stimuli. The differences in L1 and L2 affective processing suggest that in some bilingual speakers, in particular late bilinguals and foreign language users, respective languages may be differentially embodied, with the later learned language processed semantically but not affectively. This difference accounts for the reduction of framing biases in L2 processing in the study by Keysar et al. (2012). The follow-up discussion identifies the limits of the findings to date in terms of participant populations, levels of processing, and types of stimuli, puts forth alternative explanations of the documented effects, and articulates predictions to be tested in future research. PMID:23163422

  13. Climate Extremes and Land-Use Change: Effects on Ecosystem Processes and Services

    NASA Astrophysics Data System (ADS)

    Bahn, Michael; Erb, Karlheinz; Hasibeder, Roland; Mayr, Stefan; Niedertscheider, Maria; Oberhuber, Walter; Tappeiner, Ulrike; Tasser, Erich; Viovy, Nicolas; Wieser, Gerhard

    2016-04-01

    Extreme climatic events, in particular droughts and heatwaves, have significant impacts on ecosystem carbon and water cycles and a range of related ecosystem services. It is expected that in the coming decades the return intervals and severities of extreme droughts will increase substantially and may result in the passing of thresholds of ecosystem functioning, potentially causing legacy effects, which are so far poorly understood. Observational evidence suggests that different land cover types (forest, grassland) are differently influenced by extreme drought, but there is a lack of knowledge whether and how future, increasingly severe climate extremes will affect their concurrent and lagged responses, as well as land-use decisions determining future shifts in land cover. The ClimLUC project aims to understand how extreme summer drought affects carbon and water dynamics of mountain ecosystems under different land uses, and to analyse implications for ecosystem service provisioning. Overall, we hypothesize that land-use change alters the effects of extreme summer drought on ecosystem processes and the related services, grassland responding more rapidly and strongly but being more resilient to extreme drought than forest. To address the aims and hypotheses, we will 1) test experimentally how (a) a managed, (b) an abandoned mountain grassland and (c) an adjacent subalpine forest respond to a progressive extreme drought and will analyse threshold responses of carbon and water dynamics and their implications for ecosystem services (timber and fodder production, carbon sequestration, water provisioning); 2) quantify carry-over effects of the extreme event on ecosystem processes and services; 3) project and attribute future carbon and water cycle responses to extreme drought and related socio-economic changes, based on a process-based dynamic general vegetation model; 4) analyse the interrelation between land-use changes and the occurrence and severity of past and future

  14. Small but Powerful: Top Predator Local Extinction Affects Ecosystem Structure and Function in an Intermittent Stream

    PubMed Central

    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

  15. Soil restoration with organic amendments: linking cellular functionality and ecosystem processes

    NASA Astrophysics Data System (ADS)

    Bastida, F.; Selevsek, N.; Torres, I. F.; Hernández, T.; García, C.

    2015-10-01

    A hot topic in recent decades, the application of organic amendments to arid-degraded soils has been shown to benefit microbially-mediated processes. However, despite the importance of soils for global sustainability, a gap has not been addressed yet in soil science: is there any connection between ecosystem-community processes, cellular functionality, and microbial lifestyles (i.e. oligotrophy-copiotrophy) in restored soils? Together with classical ecosystem indicators (fatty-acids, extracellular-enzyme activities, basal respiration), state-of-the-art metaproteomics was applied to fill this gap in a model-restoration experiment initiated 10-years ago by the addition of sewage-sludge and compost. Organic amendment strongly impacted ecosystem processes. Furthermore, the type of material used induced differences in the cellular functionalities through variations in the percentages of proteins involved in translation, transcription, energy production and C-fixation. We conclude that the long-term impact of organic restoration goes beyond ecosystem processes and affects cellular functionalities and phyla-lifestyles coupled with differences in microbial-community structures.

  16. Soil restoration with organic amendments: linking cellular functionality and ecosystem processes.

    PubMed

    Bastida, F; Selevsek, N; Torres, I F; Hernández, T; García, C

    2015-10-27

    A hot topic in recent decades, the application of organic amendments to arid-degraded soils has been shown to benefit microbially-mediated processes. However, despite the importance of soils for global sustainability, a gap has not been addressed yet in soil science: is there any connection between ecosystem-community processes, cellular functionality, and microbial lifestyles (i.e. oligotrophy-copiotrophy) in restored soils? Together with classical ecosystem indicators (fatty-acids, extracellular-enzyme activities, basal respiration), state-of-the-art metaproteomics was applied to fill this gap in a model-restoration experiment initiated 10-years ago by the addition of sewage-sludge and compost. Organic amendment strongly impacted ecosystem processes. Furthermore, the type of material used induced differences in the cellular functionalities through variations in the percentages of proteins involved in translation, transcription, energy production and C-fixation. We conclude that the long-term impact of organic restoration goes beyond ecosystem processes and affects cellular functionalities and phyla-lifestyles coupled with differences in microbial-community structures.

  17. Soil restoration with organic amendments: linking cellular functionality and ecosystem processes

    PubMed Central

    Bastida, F.; Selevsek, N.; Torres, I. F.; Hernández, T.; García, C.

    2015-01-01

    A hot topic in recent decades, the application of organic amendments to arid-degraded soils has been shown to benefit microbially-mediated processes. However, despite the importance of soils for global sustainability, a gap has not been addressed yet in soil science: is there any connection between ecosystem-community processes, cellular functionality, and microbial lifestyles (i.e. oligotrophy-copiotrophy) in restored soils? Together with classical ecosystem indicators (fatty-acids, extracellular-enzyme activities, basal respiration), state-of-the-art metaproteomics was applied to fill this gap in a model-restoration experiment initiated 10-years ago by the addition of sewage-sludge and compost. Organic amendment strongly impacted ecosystem processes. Furthermore, the type of material used induced differences in the cellular functionalities through variations in the percentages of proteins involved in translation, transcription, energy production and C-fixation. We conclude that the long-term impact of organic restoration goes beyond ecosystem processes and affects cellular functionalities and phyla-lifestyles coupled with differences in microbial-community structures. PMID:26503516

  18. Soil restoration with organic amendments: linking cellular functionality and ecosystem processes.

    PubMed

    Bastida, F; Selevsek, N; Torres, I F; Hernández, T; García, C

    2015-01-01

    A hot topic in recent decades, the application of organic amendments to arid-degraded soils has been shown to benefit microbially-mediated processes. However, despite the importance of soils for global sustainability, a gap has not been addressed yet in soil science: is there any connection between ecosystem-community processes, cellular functionality, and microbial lifestyles (i.e. oligotrophy-copiotrophy) in restored soils? Together with classical ecosystem indicators (fatty-acids, extracellular-enzyme activities, basal respiration), state-of-the-art metaproteomics was applied to fill this gap in a model-restoration experiment initiated 10-years ago by the addition of sewage-sludge and compost. Organic amendment strongly impacted ecosystem processes. Furthermore, the type of material used induced differences in the cellular functionalities through variations in the percentages of proteins involved in translation, transcription, energy production and C-fixation. We conclude that the long-term impact of organic restoration goes beyond ecosystem processes and affects cellular functionalities and phyla-lifestyles coupled with differences in microbial-community structures. PMID:26503516

  19. Microbial interactions affecting the natural transformation of Bacillus subtilis in a model aquatic ecosystem.

    PubMed

    Matsui, Kazuaki; Ishii, Nobuyoshi; Kawabata, Zen'ichiro

    2003-08-01

    The involvement of microbial interactions in natural transformation of bacteria was evaluated using an aquatic model system. For this purpose, the naturally transformable Bacillus subtilis was used as the model bacterium which was co-cultivated with the protist Tetrahymena thermophila (a consumer) and/or the photosynthetic alga Euglena gracilis (a producer). Co-cultivation with as few as 10(2) individuals ml(-1) of T. thermophila lowered the number of transformants to less than the detectable level (<1x10(0) ml(-1)), while co-cultivation with E. gracilis did not. Metabolites from co-cultures of T. thermophila and B. subtilis also decreased the number of transformants to less than the detectable level, while metabolites from co-culture of T. thermophila and B. subtilis with E. gracilis did not. Thus, the introduction of transformation inhibitory factor(s) by the grazing of T. thermophila and the attenuation of this inhibitory factor(s) by E. gracilis is indicated. These observations suggest that biological components do affect the natural transformation of B. subtilis. The study described is the first to suggest that ecological interactions are responsible not only for the carbon and energy cycles, but also for the processes governing horizontal transfer of genes, in microbial ecosystems.

  20. Ecosystem change in the southern Benguela and the underlying processes

    NASA Astrophysics Data System (ADS)

    Blamey, Laura K.; Shannon, Lynne J.; Bolton, John J.; Crawford, Robert J. M.; Dufois, Francois; Evers-King, Hayley; Griffiths, Charles L.; Hutchings, Laurence; Jarre, Astrid; Rouault, Mathieu; Watermeyer, Katherine E.; Winker, Henning

    2015-04-01

    Overfishing and human-induced climate change are putting severe pressure on marine ecosystems. In the southern Benguela, most of South Africa's commercial fisheries have a long history of exploitation and this, coupled with spatio-temporal changes in key species over the last three decades has severely impacted some of South Africa's fisheries and ecosystems. This review summarizes these spatio-temporal changes and investigates possible drivers thereof. It incorporates both past and current research, with a large portion of the latter having formed part of the University of Cape Town's Ma-Re BASICS (Marine Research in the Benguela and Agulhas Systems for supporting Interdisciplinary Climate-change Science) 2010-2013 program. Almost all described changes involve a temporal decline or a spatial shift in species. Fishing seems to have played a role in many of the observed stock declines, for example through geographically disproportionate catches in relation to stock distribution. In some cases, changes in the physical environment seem to have played an additional role, e.g., rock lobsters on the west coast have been affected by fishing as well as changes in the physical environment. In almost all cases these changes have taken place since the 1980s/1990s, except for one or two resources, which have experienced declines since at least the mid 20th century. Spatial shifts in species have either involved an eastward expansion of cool-water species, including kelps, rock lobster and pelagic fish, or a retraction of warm-water species such as the brown mussel, suggesting a cooling of inshore waters along the south-west coast since the 1980s. This suggested cooling is revealed in ocean temperature (SST Pathfinder), wind and upwelling data for the Cape Peninsula and south-west coast region during the same period. The absence or inconsistency of long-term data is problematic when trying to identify drivers of ecosystem change, and actual ecosystem change itself. We discuss

  1. South Florida wetlands ecosystem; biogeochemical processes in peat

    USGS Publications Warehouse

    Orem, William; ,

    1996-01-01

    The South Florida wetlands ecosystem is an environment of great size and ecological diversity (figs. 1 and 2). The landscape diversity and subtropical setting of this ecosystem provide a habitat for an abundance of plants and wildlife, some of which are unique to South Florida. South Florida wetlands are currently in crisis, however, due to the combined effects of agriculture, urbanization, and nearly 100 years of water management. Serious problems facing this ecosystem include (1) phosphorus contamination producing nutrient enrichment, which is causing changes in the native vegetation, (2) methylmercury contamination of fish and other wildlife, which poses a potential threat to human health, (3) changes in the natural flow of water in the region, resulting in more frequent drying of wetlands, loss of organic soils, and a reduction in freshwater flow to Florida Bay, (4) hypersalinity, massive algal blooms, and seagrass loss in parts of Florida Bay, and (5) a decrease in wildlife populations, especially those of wading birds. This U.S. Geological Survey (USGS) project focuses on the role of organic-rich sediments (peat) of South Florida wetlands in regulating the concentrations and impact of important chemical species in the environment. The cycling of carbon, nitrogen, phosphorus, and sulfur in peat is an important factor in the regulation of water quality in the South Florida wetlands ecosystem. These elements are central to many of the contamination issues facing South Florida wetlands, such as nutrient enrichment, mercury toxicity, and loss of peat. Many important chemical and biological reactions occur in peat and control the fate of chemical species in wetlands. Wetland scientists often refer to these reactions as biogeochemical processes, because they are chemical reactions usually mediated by microorganisms in a geological environment. An understanding of the biogeochemical processes in peat of South Florida wetlands will provide a basis for evaluating the

  2. Suppression of savanna ants alters invertebrate composition and influences key ecosystem processes.

    PubMed

    Parr, C L; Eggleton, P; Davies, A B; Evans, T A; Holdsworth, S

    2016-06-01

    In almost every ecosystem, ants (Hymenoptera: Formicidae) are the dominant terrestrial invertebrate group. Their functional value was highlighted by Wilson (1987) who famously declared that invertebrates are the "little things that run the world." However, while it is generally accepted that ants fulfil important functions, few studies have tested these assumptions and demonstrated what happens in their absence. We report on a novel large-scale field experiment in undisturbed savanna habitat where we examined how ants influence the abundance of other invertebrate taxa in the system, and affect the key processes of decomposition and herbivory. Our experiment demonstrated that ants suppressed the abundance and activity of beetles, millipedes, and termites, and also influenced decomposition rates and levels of herbivory. Our study is the first to show that top-down control of termites by ants can have important ecosystem consequences. Further studies are needed to elucidate the effects ant communities have on other aspects of the ecosystem (e.g., soils, nutrient cycling, the microbial community) and how their relative importance for ecosystem function varies among ecosystem types (e.g., savanna vs. forest).

  3. Suppression of savanna ants alters invertebrate composition and influences key ecosystem processes.

    PubMed

    Parr, C L; Eggleton, P; Davies, A B; Evans, T A; Holdsworth, S

    2016-06-01

    In almost every ecosystem, ants (Hymenoptera: Formicidae) are the dominant terrestrial invertebrate group. Their functional value was highlighted by Wilson (1987) who famously declared that invertebrates are the "little things that run the world." However, while it is generally accepted that ants fulfil important functions, few studies have tested these assumptions and demonstrated what happens in their absence. We report on a novel large-scale field experiment in undisturbed savanna habitat where we examined how ants influence the abundance of other invertebrate taxa in the system, and affect the key processes of decomposition and herbivory. Our experiment demonstrated that ants suppressed the abundance and activity of beetles, millipedes, and termites, and also influenced decomposition rates and levels of herbivory. Our study is the first to show that top-down control of termites by ants can have important ecosystem consequences. Further studies are needed to elucidate the effects ant communities have on other aspects of the ecosystem (e.g., soils, nutrient cycling, the microbial community) and how their relative importance for ecosystem function varies among ecosystem types (e.g., savanna vs. forest). PMID:27459790

  4. Cognitive and Affective Processes Underlying Career Change

    ERIC Educational Resources Information Center

    Muja, Naser; Appelbaum, Steven H.

    2012-01-01

    Purpose: Aligning social identity and career identity has become increasingly complex due to growth in the pursuit of meaningful careers that offer very long-term personal satisfaction and stability. This paper aims to explore the complex cognitive and affective thought process involved in the conscious planning of voluntary career change.…

  5. Lead contamination of an old shooting range affecting the local ecosystem--A case study with a holistic approach.

    PubMed

    Rantalainen, Minna-Liisa; Torkkeli, Minna; Strömmer, Rauni; Setälä, Heikki

    2006-10-01

    The aim of this case study was to uncover the consequences of lead pellet-derived heavy lead contamination at a cast-off shooting range in southern Finland, covering aspects from soil chemistry and biology up to ecosystem level. The observed changes in the soil properties of the most contaminated areas suggest that the contamination may be disturbing processes of decomposition and nutrient mineralisation. Also two functionally important groups of soil organisms, microbes (as analysed using the PLFA analysis) and enchytraeid worms, were negatively affected by the contamination. Furthermore, there was an indication of reduced pine litter production at the contaminated areas. On the other hand, lead contamination appears not to have affected pine growth or soil-dwelling nematodes and microarthropods, and the general outlook of the whole ecosystem is that of a healthy forest. Thus, the boreal forest ecosystem studied as a whole appears to bear strong resistance to contamination, despite negative effects of lead on many of its components. This resistance may result from e.g. low bioavailability of lead, avoidance of the most contaminated soil horizons and microsites by the organisms, and functional redundancy and development of lead-tolerant populations amongst the organisms. The relative importance of these factors and the mechanisms behind them will be investigated in forthcoming studies.

  6. Landsat ecosystem disturbance adaptive processing system (LEDAPS) algorithm description

    USGS Publications Warehouse

    Schmidt, Gail; Jenkerson, Calli; Masek, Jeffrey; Vermote, Eric; Gao, Feng

    2013-01-01

    The Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS) software was originally developed by the National Aeronautics and Space Administration–Goddard Space Flight Center and the University of Maryland to produce top-of-atmosphere reflectance from LandsatThematic Mapper and Enhanced Thematic Mapper Plus Level 1 digital numbers and to apply atmospheric corrections to generate a surface-reflectance product.The U.S. Geological Survey (USGS) has adopted the LEDAPS algorithm for producing the Landsat Surface Reflectance Climate Data Record.This report discusses the LEDAPS algorithm, which was implemented by the USGS.

  7. Macrofauna assemblage composition and soil moisture interact to affect soil ecosystem functions

    NASA Astrophysics Data System (ADS)

    Collison, E. J.; Riutta, T.; Slade, E. M.

    2013-02-01

    Changing climatic conditions and habitat fragmentation are predicted to alter the soil moisture conditions of temperate forests. It is not well understood how the soil macrofauna community will respond to changes in soil moisture, and how changes to species diversity and community composition may affect ecosystem functions, such as litter decomposition and soil fluxes. Moreover, few studies have considered the interactions between the abiotic and biotic factors that regulate soil processes. Here we attempt to disentangle the interactive effects of two of the main factors that regulate soil processes at small scales - moisture and macrofauna assemblage composition. The response of assemblages of three common temperate soil invertebrates (Glomeris marginata Villers, Porcellio scaber Latreille and Philoscia muscorum Scopoli) to two contrasting soil moisture levels was examined in a series of laboratory mesocosm experiments. The contribution of the invertebrates to the leaf litter mass loss of two common temperate tree species of contrasting litter quality (easily decomposing Fraxinus excelsior L. and recalcitrant Quercus robur L.) and to soil CO2 fluxes were measured. Both moisture conditions and litter type influenced the functioning of the invertebrate assemblages, which was greater in high moisture conditions compared with low moisture conditions and on good quality vs. recalcitrant litter. In high moisture conditions, all macrofauna assemblages functioned at equal rates, whereas in low moisture conditions there were pronounced differences in litter mass loss among the assemblages. This indicates that species identity and assemblage composition are more important when moisture is limited. We suggest that complementarity between macrofauna species may mitigate the reduced functioning of some species, highlighting the importance of maintaining macrofauna species richness.

  8. Forest Fragmentation and Selective Logging Have Inconsistent Effects on Multiple Animal-Mediated Ecosystem Processes in a Tropical Forest

    PubMed Central

    Schleuning, Matthias; Farwig, Nina; Peters, Marcell K.; Bergsdorf, Thomas; Bleher, Bärbel; Brandl, Roland; Dalitz, Helmut; Fischer, Georg; Freund, Wolfram; Gikungu, Mary W.; Hagen, Melanie; Garcia, Francisco Hita; Kagezi, Godfrey H.; Kaib, Manfred; Kraemer, Manfred; Lung, Tobias; Schaab, Gertrud; Templin, Mathias; Uster, Dana; Wägele, J. Wolfgang; Böhning-Gaese, Katrin

    2011-01-01

    Forest fragmentation and selective logging are two main drivers of global environmental change and modify biodiversity and environmental conditions in many tropical forests. The consequences of these changes for the functioning of tropical forest ecosystems have rarely been explored in a comprehensive approach. In a Kenyan rainforest, we studied six animal-mediated ecosystem processes and recorded species richness and community composition of all animal taxa involved in these processes. We used linear models and a formal meta-analysis to test whether forest fragmentation and selective logging affected ecosystem processes and biodiversity and used structural equation models to disentangle direct from biodiversity-related indirect effects of human disturbance on multiple ecosystem processes. Fragmentation increased decomposition and reduced antbird predation, while selective logging consistently increased pollination, seed dispersal and army-ant raiding. Fragmentation modified species richness or community composition of five taxa, whereas selective logging did not affect any component of biodiversity. Changes in the abundance of functionally important species were related to lower predation by antbirds and higher decomposition rates in small forest fragments. The positive effects of selective logging on bee pollination, bird seed dispersal and army-ant raiding were direct, i.e. not related to changes in biodiversity, and were probably due to behavioural changes of these highly mobile animal taxa. We conclude that animal-mediated ecosystem processes respond in distinct ways to different types of human disturbance in Kakamega Forest. Our findings suggest that forest fragmentation affects ecosystem processes indirectly by changes in biodiversity, whereas selective logging influences processes directly by modifying local environmental conditions and resource distributions. The positive to neutral effects of selective logging on ecosystem processes show that the

  9. Hydrologically driven ecosystem processes determine the distribution and persistence of ecosystem-specialist predators under climate change.

    PubMed

    Carroll, Matthew J; Heinemeyer, Andreas; Pearce-Higgins, James W; Dennis, Peter; West, Chris; Holden, Joseph; Wallage, Zoe E; Thomas, Chris D

    2015-01-01

    Climate change has the capacity to alter physical and biological ecosystem processes, jeopardizing the survival of associated species. This is a particular concern in cool, wet northern peatlands that could experience warmer, drier conditions. Here we show that climate, ecosystem processes and food chains combine to influence the population performance of species in British blanket bogs. Our peatland process model accurately predicts water-table depth, which predicts abundance of craneflies (keystone invertebrates), which in turn predicts observed abundances and population persistence of three ecosystem-specialist bird species that feed on craneflies during the breeding season. Climate change projections suggest that falling water tables could cause 56-81% declines in cranefly abundance and, hence, 15-51% reductions in the abundances of these birds by 2051-2080. We conclude that physical (precipitation, temperature and topography), biophysical (evapotranspiration and desiccation of invertebrates) and ecological (food chains) processes combine to determine the distributions and survival of ecosystem-specialist predators. PMID:26227623

  10. Hydrologically driven ecosystem processes determine the distribution and persistence of ecosystem-specialist predators under climate change

    PubMed Central

    Carroll, Matthew J.; Heinemeyer, Andreas; Pearce-Higgins, James W.; Dennis, Peter; West, Chris; Holden, Joseph; Wallage, Zoe E.; Thomas, Chris D.

    2015-01-01

    Climate change has the capacity to alter physical and biological ecosystem processes, jeopardizing the survival of associated species. This is a particular concern in cool, wet northern peatlands that could experience warmer, drier conditions. Here we show that climate, ecosystem processes and food chains combine to influence the population performance of species in British blanket bogs. Our peatland process model accurately predicts water-table depth, which predicts abundance of craneflies (keystone invertebrates), which in turn predicts observed abundances and population persistence of three ecosystem-specialist bird species that feed on craneflies during the breeding season. Climate change projections suggest that falling water tables could cause 56–81% declines in cranefly abundance and, hence, 15–51% reductions in the abundances of these birds by 2051–2080. We conclude that physical (precipitation, temperature and topography), biophysical (evapotranspiration and desiccation of invertebrates) and ecological (food chains) processes combine to determine the distributions and survival of ecosystem-specialist predators. PMID:26227623

  11. Hydrologically driven ecosystem processes determine the distribution and persistence of ecosystem-specialist predators under climate change.

    PubMed

    Carroll, Matthew J; Heinemeyer, Andreas; Pearce-Higgins, James W; Dennis, Peter; West, Chris; Holden, Joseph; Wallage, Zoe E; Thomas, Chris D

    2015-07-31

    Climate change has the capacity to alter physical and biological ecosystem processes, jeopardizing the survival of associated species. This is a particular concern in cool, wet northern peatlands that could experience warmer, drier conditions. Here we show that climate, ecosystem processes and food chains combine to influence the population performance of species in British blanket bogs. Our peatland process model accurately predicts water-table depth, which predicts abundance of craneflies (keystone invertebrates), which in turn predicts observed abundances and population persistence of three ecosystem-specialist bird species that feed on craneflies during the breeding season. Climate change projections suggest that falling water tables could cause 56-81% declines in cranefly abundance and, hence, 15-51% reductions in the abundances of these birds by 2051-2080. We conclude that physical (precipitation, temperature and topography), biophysical (evapotranspiration and desiccation of invertebrates) and ecological (food chains) processes combine to determine the distributions and survival of ecosystem-specialist predators.

  12. Ecosystem experiments

    SciTech Connect

    Mooney, H.A.; Medina, E.; Schindler, D.W.; Schulze, E.D.; Walker, B.H.

    1991-01-01

    Large scale, human-induced modifications to terrestrial and hydrological systems have been a major factor in contributing to global change. The objective of this book is to explore the potential of ecosystem experimentation as a tool to understanding and predicting more precisely the consequences of our changing biosphere. The papers in this book are the result of two SCOPE workshops to evaluated understanding of the response of ecosystems to large scale perturbations and to design ecosystem experiments to study the impace of increased atmospheric carbon dioxide concentrations on ecosystem processes. The general topics addressed include the following: how changes in driving variables affect different biotic interactions within ecosystems; the human role in modifying forest structure and the resulting ecosystem processes; the role of ecosystem experiments in the study of controlling factors such as hydrological controls, temperature, and biotic controlles; analysis of ecosystem dynamics as a complex and chaotic system; role of ecosystem experiments in the study of the impact of acid deposition; role of ecosystem experimentation in the study of global change impace on the biosphere and the biospheric feedbacks to global environmental change.

  13. Microphysical Processes Affecting the Pinatubo Volcanic Plume

    NASA Technical Reports Server (NTRS)

    Hamill, Patrick; Houben, Howard; Young, Richard; Turco, Richard; Zhao, Jingxia

    1996-01-01

    In this paper we consider microphysical processes which affect the formation of sulfate particles and their size distribution in a dispersing cloud. A model for the dispersion of the Mt. Pinatubo volcanic cloud is described. We then consider a single point in the dispersing cloud and study the effects of nucleation, condensation and coagulation on the time evolution of the particle size distribution at that point.

  14. Stress modulation of cognitive and affective processes.

    PubMed

    Campeau, Serge; Liberzon, Israel; Morilak, David; Ressler, Kerry

    2011-09-01

    This review summarizes the major discussion points of a symposium on stress modulation of cognitive and affective processes, which was held during the 2010 workshop on the neurobiology of stress (Boulder, CO, USA). The four discussants addressed a number of specific cognitive and affective factors that are modulated by exposure to acute or repeated stress. Dr David Morilak discussed the effects of various repeated stress situations on cognitive flexibility, as assessed with a rodent model of attentional set-shifting task, and how performance on slightly different aspects of this test is modulated by different prefrontal regions through monoaminergic neurotransmission. Dr Serge Campeau summarized the findings of several studies exploring a number of factors and brain regions that regulate habituation of various autonomic and neuroendocrine responses to repeated audiogenic stress exposures. Dr Kerry Ressler discussed a body of work exploring the modulation and extinction of fear memories in rodents and humans, especially focusing on the role of key neurotransmitter systems including excitatory amino acids and brain-derived neurotrophic factor. Dr Israel Liberzon presented recent results on human decision-making processes in response to exogenous glucocorticoid hormone administration. Overall, these discussions are casting a wider framework on the cognitive/affective processes that are distinctly regulated by the experience of stress and some of the brain regions and neurotransmitter systems associated with these effects.

  15. Stress modulation of cognitive and affective processes.

    PubMed

    Campeau, Serge; Liberzon, Israel; Morilak, David; Ressler, Kerry

    2011-09-01

    This review summarizes the major discussion points of a symposium on stress modulation of cognitive and affective processes, which was held during the 2010 workshop on the neurobiology of stress (Boulder, CO, USA). The four discussants addressed a number of specific cognitive and affective factors that are modulated by exposure to acute or repeated stress. Dr David Morilak discussed the effects of various repeated stress situations on cognitive flexibility, as assessed with a rodent model of attentional set-shifting task, and how performance on slightly different aspects of this test is modulated by different prefrontal regions through monoaminergic neurotransmission. Dr Serge Campeau summarized the findings of several studies exploring a number of factors and brain regions that regulate habituation of various autonomic and neuroendocrine responses to repeated audiogenic stress exposures. Dr Kerry Ressler discussed a body of work exploring the modulation and extinction of fear memories in rodents and humans, especially focusing on the role of key neurotransmitter systems including excitatory amino acids and brain-derived neurotrophic factor. Dr Israel Liberzon presented recent results on human decision-making processes in response to exogenous glucocorticoid hormone administration. Overall, these discussions are casting a wider framework on the cognitive/affective processes that are distinctly regulated by the experience of stress and some of the brain regions and neurotransmitter systems associated with these effects. PMID:21790481

  16. Loss of Rare Fish Species from Tropical Floodplain Food Webs Affects Community Structure and Ecosystem Multifunctionality in a Mesocosm Experiment

    PubMed Central

    Pendleton, Richard M.; Hoeinghaus, David J.; Gomes, Luiz C.; Agostinho, Angelo A.

    2014-01-01

    Experiments with realistic scenarios of species loss from multitrophic ecosystems may improve insight into how biodiversity affects ecosystem functioning. Using 1000 L mesocoms, we examined effects of nonrandom species loss on community structure and ecosystem functioning of experimental food webs based on multitrophic tropical floodplain lagoon ecosystems. Realistic biodiversity scenarios were developed based on long-term field surveys, and experimental assemblages replicated sequential loss of rare species which occurred across all trophic levels of these complex food webs. Response variables represented multiple components of ecosystem functioning, including nutrient cycling, primary and secondary production, organic matter accumulation and whole ecosystem metabolism. Species richness significantly affected ecosystem function, even after statistically controlling for potentially confounding factors such as total biomass and direct trophic interactions. Overall, loss of rare species was generally associated with lower nutrient concentrations, phytoplankton and zooplankton densities, and whole ecosystem metabolism when compared with more diverse assemblages. This pattern was also observed for overall ecosystem multifunctionality, a combined metric representing the ability of an ecosystem to simultaneously maintain multiple functions. One key exception was attributed to time-dependent effects of intraguild predation, which initially increased values for most ecosystem response variables, but resulted in decreases over time likely due to reduced nutrient remineralization by surviving predators. At the same time, loss of species did not result in strong trophic cascades, possibly a result of compensation and complexity of these multitrophic ecosystems along with a dominance of bottom-up effects. Our results indicate that although rare species may comprise minor components of communities, their loss can have profound ecosystem consequences across multiple trophic

  17. Loss of rare fish species from tropical floodplain food webs affects community structure and ecosystem multifunctionality in a mesocosm experiment.

    PubMed

    Pendleton, Richard M; Hoeinghaus, David J; Gomes, Luiz C; Agostinho, Angelo A

    2014-01-01

    Experiments with realistic scenarios of species loss from multitrophic ecosystems may improve insight into how biodiversity affects ecosystem functioning. Using 1000 L mesocoms, we examined effects of nonrandom species loss on community structure and ecosystem functioning of experimental food webs based on multitrophic tropical floodplain lagoon ecosystems. Realistic biodiversity scenarios were developed based on long-term field surveys, and experimental assemblages replicated sequential loss of rare species which occurred across all trophic levels of these complex food webs. Response variables represented multiple components of ecosystem functioning, including nutrient cycling, primary and secondary production, organic matter accumulation and whole ecosystem metabolism. Species richness significantly affected ecosystem function, even after statistically controlling for potentially confounding factors such as total biomass and direct trophic interactions. Overall, loss of rare species was generally associated with lower nutrient concentrations, phytoplankton and zooplankton densities, and whole ecosystem metabolism when compared with more diverse assemblages. This pattern was also observed for overall ecosystem multifunctionality, a combined metric representing the ability of an ecosystem to simultaneously maintain multiple functions. One key exception was attributed to time-dependent effects of intraguild predation, which initially increased values for most ecosystem response variables, but resulted in decreases over time likely due to reduced nutrient remineralization by surviving predators. At the same time, loss of species did not result in strong trophic cascades, possibly a result of compensation and complexity of these multitrophic ecosystems along with a dominance of bottom-up effects. Our results indicate that although rare species may comprise minor components of communities, their loss can have profound ecosystem consequences across multiple trophic

  18. Quantifying Ecological Memory of Plant and Ecosystem Processes in Variable Environments

    NASA Astrophysics Data System (ADS)

    Ogle, K.; Barron-Gafford, G. A.; Bentley, L.; Cable, J.; Lucas, R.; Huxman, T. E.; Loik, M. E.; Smith, S. D.; Tissue, D.

    2010-12-01

    Precipitation, soil water, and other factors affect plant and ecosystem processes at multiple time scales. A common assumption is that water availability at a given time directly affects processes at that time. Recent work, especially in pulse-driven, semiarid systems, shows that antecedent water availability, averaged over several days to a couple weeks, can be just as or more important than current water status. Precipitation patterns of previous seasons or past years can also impact plant and ecosystem functioning in many systems. However, we lack an analytical framework for quantifying the importance of and time-scale over which past conditions affect current processes. This study explores the ecological memory of a variety of plant and ecosystem processes. We use memory as a metaphor to describe the time-scale over which antecedent conditions affect the current process. Existing approaches for incorporating antecedent effects arbitrarily select the antecedent integration period (e.g., the past 2 weeks) and the relative importance of past conditions (e.g., assign equal or linearly decreasing weights to past events). In contrast, we utilize a hierarchical Bayesian approach to integrate field data with process-based models, yielding posterior distributions for model parameters, including the duration of the ecological memory (integration period) and the relative importance of past events (weights) to this memory. We apply our approach to data spanning diverse temporal scales and four semiarid sites in the western US: leaf-level stomatal conductance (gs, sub-hourly scale), soil respiration (Rs, hourly to daily scale), and net primary productivity (NPP) and tree-ring widths (annual scale). For gs, antecedent factors (daily rainfall and temperature, hourly vapor pressure deficit) and current soil water explained up to 72% of the variation in gs in the Chihuahuan Desert, with a memory of 10 hours for a grass and 4 days for a shrub. Antecedent factors (past soil water

  19. Impact of Chronic Hypercortisolemia on Affective Processing

    PubMed Central

    Langenecker, Scott A.; Weisenbach, Sara L.; Giordani, Bruno; Briceno, Emily M.; GuidottiBreting, Leslie M.; Schallmo, Michael-Paul; Leon, Hadia M.; Noll, Douglas C.; Zubieta, Jon-Kar; Schteingart, David E.; Starkman, Monica N.

    2011-01-01

    Cushing syndrome (CS) is the classic condition of cortisol dysregulation, and cortisol dysregulation is the prototypic finding in Major Depressive Disorder (MDD). We hypothesized that subjects with active CS would show dysfunction in frontal and limbic structures relevant to affective networks, and also manifest poorer facial affect identification accuracy, a finding reported in MDD.Twenty-one patients with confirmed CS (20 ACTH-dependent and 1 ACTH-independent) were compared to 21 healthy controlsubjects. Identification of affective facial expressions (Facial Emotion Perception Test) was conducted in a 3 Tesla GE fMRI scanner using BOLD fMRI signal. The impact of disease (illness duration, current hormone elevation and degree of disruption of circadian rhythm), performance, and comorbid conditions secondary to hypercortisolemia were evaluated.CS patients made more errors in categorizing facial expressions and had less activation in left anterior superior temporal gyrus, a region important in emotion processing. CS patients showed higher activation in frontal, medial, and subcortical regions relative to controls. Two regions of elevated activation in CS, left middle frontal and lateral posterior/pulvinar areas, were positively correlated with accuracy in emotion identification in the CS group, reflecting compensatory recruitment. In addition, within the CSgroup, greater activation in left dorsal anterior cingulatewas related to greater severity of hormone dysregulation. In conclusion, cortisol dysregulation in CS patients is associated with problems in accuracy of affective discrimination and altered activation of brain structures relevant to emotion perception, processing and regulation, similar to the performance decrements and brain regions shown to be dysfunctional in MDD. PMID:21787793

  20. Ecosystem Modeling of Biological Processes to Global Budgets

    NASA Technical Reports Server (NTRS)

    Christopher, Potter S.; Condon, Estelle (Technical Monitor)

    2000-01-01

    biosphere effects on atmospheric composition is the ecosystem level. These assumptions are the foundation for developing modern emission budgets for biogenic gases such as carbon dioxide, methane, carbon monoxide, isoprene, nitrous and nitric oxide, and ammonia. Such emission budgets commonly include information on seasonal flux patterns, typical diurnal profiles, and spatial resolution of at least one degree latitude/longitude for the globe. On the basis of these budgets, it is possible to compute 'base emission rates' for the major biogenic trace gases from both terrestrial and ocean sources, which may be useful benchmarks for defining the gas production rates of organisms, especially those from early Earth history, which are required to generate a detectable signal on a global atmosphere. This type of analysis is also the starting point for evaluation of the 'biological processes to global gas budget' extrapolation procedure described above for early Earth ecosystems.

  1. Irrigation agriculture affects organic matter decomposition in semi-arid terrestrial and aquatic ecosystems.

    PubMed

    Arroita, Maite; Causapé, Jesús; Comín, Francisco A; Díez, Joserra; Jimenez, Juan José; Lacarta, Juan; Lorente, Carmen; Merchán, Daniel; Muñiz, Selene; Navarro, Enrique; Val, Jonatan; Elosegi, Arturo

    2013-12-15

    Many dryland areas are being converted into intensively managed irrigation crops, what can disrupt the hydrological regime, degrade soil and water quality, enhance siltation, erosion and bank instability, and affect biological communities. Still, the impacts of irrigation schemes on the functioning of terrestrial and aquatic ecosystems are poorly understood. Here we assess the effects of irrigation agriculture on breakdown of coarse organic matter in soil and water. We measured breakdown rates of alder and holm oak leaves, and of poplar sticks in terrestrial and aquatic sites following a gradient of increasing irrigation agriculture in a semi-arid Mediterranean basin transformed into irrigation agriculture in 50% of its surface. Spatial patterns of stick breakdown paralleled those of leaf breakdown. In soil, stick breakdown rates were extremely low in non-irrigated sites (0.0001-0.0003 day(-1)), and increased with the intensity of agriculture (0.0018-0.0044 day(-1)). In water, stick breakdown rates ranged from 0.0005 to 0.001 day(-1), and increased with the area of the basin subject to irrigation agriculture. Results showed that irrigation agriculture affects functioning of both terrestrial and aquatic ecosystems, accelerating decomposition of organic matter, especially in soil. These changes can have important consequences for global carbon budgets.

  2. Irrigation agriculture affects organic matter decomposition in semi-arid terrestrial and aquatic ecosystems.

    PubMed

    Arroita, Maite; Causapé, Jesús; Comín, Francisco A; Díez, Joserra; Jimenez, Juan José; Lacarta, Juan; Lorente, Carmen; Merchán, Daniel; Muñiz, Selene; Navarro, Enrique; Val, Jonatan; Elosegi, Arturo

    2013-12-15

    Many dryland areas are being converted into intensively managed irrigation crops, what can disrupt the hydrological regime, degrade soil and water quality, enhance siltation, erosion and bank instability, and affect biological communities. Still, the impacts of irrigation schemes on the functioning of terrestrial and aquatic ecosystems are poorly understood. Here we assess the effects of irrigation agriculture on breakdown of coarse organic matter in soil and water. We measured breakdown rates of alder and holm oak leaves, and of poplar sticks in terrestrial and aquatic sites following a gradient of increasing irrigation agriculture in a semi-arid Mediterranean basin transformed into irrigation agriculture in 50% of its surface. Spatial patterns of stick breakdown paralleled those of leaf breakdown. In soil, stick breakdown rates were extremely low in non-irrigated sites (0.0001-0.0003 day(-1)), and increased with the intensity of agriculture (0.0018-0.0044 day(-1)). In water, stick breakdown rates ranged from 0.0005 to 0.001 day(-1), and increased with the area of the basin subject to irrigation agriculture. Results showed that irrigation agriculture affects functioning of both terrestrial and aquatic ecosystems, accelerating decomposition of organic matter, especially in soil. These changes can have important consequences for global carbon budgets. PMID:23891536

  3. Fluid Dynamics Applied to Streams. Physical Processes in Terrestrial and Aquatic Ecosystems, Transport Processes.

    ERIC Educational Resources Information Center

    Cowan, Christina E.

    This module is part of a series 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 module deals specifically with concepts that are basic to fluid flow and…

  4. Transpiration and Leaf Temperature. Physical Processes in Terrestrial and Aquatic Ecosystems, Transport Processes.

    ERIC Educational Resources Information Center

    Gates, David M.

    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 introduces two models of the thermal energy budget of a leaf. Typical values for…

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

    ERIC Educational Resources Information Center

    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…

  6. Light and Sound: Evolutionary Aspects. Physical Processes in Terrestrial and Aquatic Ecosystems, Transport Processes.

    ERIC Educational Resources Information Center

    Roseman, Leonard 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 module is concerned with the exchange of energy between an organism and its environment in…

  7. Realistic changes in seaweed biodiversity affect multiple ecosystem functions on a rocky shore.

    PubMed

    Bracken, Matthew E S; Williams, Susan L

    2013-09-01

    Given current threats to biodiversity, understanding the effects of diversity changes on the functions and services associated with intact ecosystems is of paramount importance. However, limited realism in most biodiversity studies makes it difficult to link the large and growing body of evidence for important functional consequences of biodiversity change to real-world losses of biodiversity. Here, we explored two methods of incorporating realism into biodiversity research: (1) the use of two-, five-, and eight-species assemblages that mimicked those that we observed in surveys of seaweed biodiversity patterns on a northern California (USA) rocky shore and the explicit comparison of those assemblages to random assemblages compiled from the same local species pool; and (2) the measurement of two fundamental ecosystem functions, nitrate uptake and photosynthesis, both of which contribute to growth of primary producers. Specifically, we measured nitrate uptake rates of seaweed assemblages as a function of initial nitrate concentrations and photosynthetic rates as a function of irradiance levels for both realistic and random assemblages of seaweeds. We only observed changes in ecosystem functioning along a richness gradient for realistic assemblages, and both maximum nitrate uptake rates (V(max)) and photosynthetic light use efficiency values (alpha(p) = P(max)/I(K)) were higher in realistic assemblages than in random assemblages. Furthermore, the parameter affected by changes in richness depended on the function being measured. Both V(max) and alpha(p) declined with increasing richness in nonrandom assemblages due to a combination of species identity effects (for V(max) and overyielding effects (for both V(max) and alpha(p)). In contrast, neither nitrate uptake efficiency values (alpha(N) = V(max)/K(s)), nor maximum photosynthetic rates (Pmax) changed along the gradient in seaweed species richness. Furthermore, overyielding was only evident in realistic assemblages

  8. Current ecosystem processes in steppe near Lake Baikal

    NASA Astrophysics Data System (ADS)

    Vanteeva, Julia

    2015-04-01

    The steppes and forest steppes complexes of Priol'khonie at the Lake Baikal (southern Siberia, Russia) were studied in this research. Recreational activity has a significant impact on the Priol'khonie region. During soviet time this area was actively used for agriculture. Nowadays, this territory is the part of Pribaikalskyi National Park and special protection is needed. As the landscapes satisfy different human demands there are many land-management conflicts. The specific climate and soil conditions and human activity lead to erosion processes on study area. Sediment loads are transferred into the Lake Baikal and cause water pollution. Consequently, vegetation cover and phytomass play an important role for regulating hydrological processes in the ecosystems. The process of phytomass formation and its proactive role playing on sedimentation and mitigate silt detaching by rill and inter-rill erosion are considered in the research as important indicators of the ecosystem functions for steppe landscapes. These indicators were studied for the different land cover types identified on the area because the study area has a large variety of steppe and forest steppe complexes, differing in the form of relief, soil types, vegetation species composition and degree of land degradation. The fieldwork was conducted in the study area in the July and August of 2013. Thirty-two experimental sites (10 x 10 m) which characterized different types of ecosystem were established. The level of landscape degradation was estimated. The method of clipping was used for the valuation of above-ground herbaceous phytomass. The phytomass of tree stands was calculated using the volume-conversion rates for forest-steppe complexes. For the quantification of transferred silt by inter-rill erosion in different conditions (vegetation, slope, soil type, anthropogenic load) a portable rainfall simulator was created with taking into account the characteristics of the study area. The aboveground

  9. Factors affecting the process performance of biofiltration

    SciTech Connect

    Kopchynski, D.M.; Farmer, R.W.; Maier, W.J.

    1996-11-01

    Biofiltration is an emerging biological treatment technology for the removal of airborne VOCs from industrial process waste streams. Removal of air-phase VOCs by biofiltration is accomplished by contacting a process airstream with an active microbial biofilm attached to a solid phase packing. VOCs that partition into the biofilm are aerobically oxidized to the endproducts of water, carbon dioxide and salts. A multiple reactor biofiltration pilot plant test program has been in progress at the University of Minnesota Environmental Engineering Laboratories since 1992. The primary goal of the program is to study factors that affect biofiltration process performance. Initial results of this test program were reported in a previous conference paper and master`s thesis. This paper presents the results of more recent studies that focus on the effects of: (1) biofilm accumulation (which in turn causes a decrease in biofilter bed porosity and packing bed surface area), (2) rates of nutrient addition, and (3) chemical properties of the target contaminant, on biofiltration removal performance. Removal performance was evaluated by determining biofilter removal capacities and efficiencies for various substrate feeds. The performance parameters were measured under constant contaminant inlet concentrations and under constant temperature. Three VOCs were selected for study and they are: MEK, (methyl ethyl ketone), xylene, and hexane. MEK, xylene, and hexane were chosen because they are representative of widely used industrial solvents and they have significantly different Henry`s law constants relative to each other (the MEK value < Xylene value < Hexane value). Henry`s law constants quantify the partitioning of a chemical between the air and water-biofilm phase and therefore can be used to correlate the effect of chemical properties on biofilter removal capacities. This paper also introduces a new model for the biofiltration process.

  10. Insights into the Processing of Carbon by Early Microbial Ecosystems

    NASA Technical Reports Server (NTRS)

    DesMarais, D.; Bebout, B.; Carpenter, S.; Discipulo, S.; Londry, K.; Habicht, K.; Turk, K.

    2003-01-01

    Interactions between Earth and the biosphere that were crucial for early biological evolution also influenced substantially the processes that circulate C between its reservoirs in the atmosphere, ocean, crust and mantle. The C-13 C-12 values of crustal carbonates and organics have recorded changes both in biological discrimination and in the relative rates of burial of organics and carbonates. A full interpretation of these patterns needs further isotopic studies of microbial ecosystems and individual anaerobes. Thus we measured carbon isotope discrimination during autotrophic and heterotrophic growth of pure cultures of sulfate-reducing bacteria and archaea (SRB and SRA). Discrimination during CO2 assimilation is significantly larger than during heterotrophic growth on lactate or acetate. SRB grown lithoautotrophically consumed less than 3% of available CO2 and exhibited substantial discrimination, as follows: Desulfobacterium autotrophicum (alpha 1.0100 to 1.0123), Desulfobacter hydrogenophilus (alpha = 0.0138), and Desulfotomuculum acetoxidans (alpha = 1.0310). Mixotrophic growth of Desulfovibrio desulfuricans on acetate and CO2 resulted in biomass with delta C-13 composition intermediate to that of the substrates. We have recently extended these experiments to include the thermophilic SRA Archeoglobus spp. Ecological forces also influence isotopic discrimination. Accordingly, we quantified the flow of C and other constituents in modern marine cyanobacterial mats, whose ancestry extends back billions of years. Such ecosystem processes shaped the biosignatures that entered sediments and atmospheres. At Guerrero Negro, BCS, Mexico, we examined mats dominated by Microcoleus (subtidal) and Lyngbya (intertidal to supratidal) cyanobacteria. During 24 hour cycles, we observed the exchange of O2 and dissolved inorganic C (DIC) between mats and the overlying water. Microcoleus mats assimilated near-equal amounts of DIC during the day as they released at night, but

  11. Ecosystem structure, function, and composition in rangelands are negatively affected by livestock grazing.

    PubMed

    Eldridge, David J; Poore, Alistair G B; Ruiz-Colmenero, Marta; Letnic, Mike; Soliveres, Santiago

    2016-06-01

    Reports of positive or neutral effects of grazing on plant species richness have prompted calls for livestock grazing to be used as a tool for managing land for conservation. Grazing effects, however, are likely to vary among different response variables, types, and intensity of grazing, and across abiotic conditions. We aimed to examine how grazing affects ecosystem structure, function, and composition. We compiled a database of 7615 records reporting an effect of grazing by sheep and cattle on 278 biotic and abiotic response variables for published studies across Australia. Using these data, we derived three ecosystem measures based on structure, function, and composition, which were compared against six contrasts of grazing pressure, ranging from low to heavy, two different herbivores (sheep, cattle), and across three different climatic zones. Grazing reduced structure (by 35%), function (24%), and composition (10%). Structure and function (but not composition) declined more when grazed by sheep and cattle together than sheep alone. Grazing reduced plant biomass (40%), animal richness (15%), and plant and animal abundance, and plant and litter cover (25%), but had no effect on plant richness nor soil function. The negative effects of grazing on plant biomass, plant cover, and soil function were more pronounced in drier environments. Grazing effects on plant and animal richness and composition were constant, or even declined, with increasing aridity. Our study represents a comprehensive continental assessment of the implications of grazing for managing Australian rangelands. Grazing effects were largely negative, even at very low levels of grazing. Overall, our results suggest that livestock grazing in Australia is unlikely to produce positive outcomes for ecosystem structure, function, and composition or even as a blanket conservation tool unless reduction in specific response variables is an explicit management objective.

  12. Revealing how species loss affects ecosystem function: the trait-based Price Equation partition.

    PubMed

    Fox, Jeremy W; Harpole, W Stanley

    2008-01-01

    Species loss can alter ecosystem function. Recent work proposes a general theoretical framework, the "Price Equation partition," for understanding how species loss affects ecosystem functions that comprise the summed contributions of individual species (e.g., primary production). The Price Equation partition shows how the difference in function between a pre-species-loss site and a post-loss site can be partitioned into effects of random loss of species richness (species-richness effect; SRE), nonrandom loss of high- or low-functioning species (species-composition effect; SCE), and post-loss changes in the functional contributions of the remaining species (context-dependence effect; CDE). However, the Price Equation partition is silent on the underlying determinants of species' functional contributions. Here we extend the Price Equation partition by using multiple regression to describe how species' functional contributions depend on species' traits. This allows us to reexpress the SCE and CDE in terms of nonrandom loss of species with particular traits (trait-based SCE), and post-loss changes in species' traits and in the relationship between species' traits and species' functional contributions (trait-based CDE). We apply this new trait-based Price Equation partition to studies of species loss from grassland plant communities and protist microcosm food webs. In both studies, post-loss changes in the relationship between species' traits and their functional contributions alter ecosystem function more than nonrandom loss of species with particular traits. The protist microcosm data also illustrate how the trait-based Price Equation partition can be applied when species' functional contributions depend in part on the traits of other species. To do this, we define "synecological" traits that quantify how unique species are (e.g., in diet) compared to other species. Context dependence in the protist microcosm experiment arises in part because species loss alters the

  13. Ecosystem structure, function, and composition in rangelands are negatively affected by livestock grazing.

    PubMed

    Eldridge, David J; Poore, Alistair G B; Ruiz-Colmenero, Marta; Letnic, Mike; Soliveres, Santiago

    2016-06-01

    Reports of positive or neutral effects of grazing on plant species richness have prompted calls for livestock grazing to be used as a tool for managing land for conservation. Grazing effects, however, are likely to vary among different response variables, types, and intensity of grazing, and across abiotic conditions. We aimed to examine how grazing affects ecosystem structure, function, and composition. We compiled a database of 7615 records reporting an effect of grazing by sheep and cattle on 278 biotic and abiotic response variables for published studies across Australia. Using these data, we derived three ecosystem measures based on structure, function, and composition, which were compared against six contrasts of grazing pressure, ranging from low to heavy, two different herbivores (sheep, cattle), and across three different climatic zones. Grazing reduced structure (by 35%), function (24%), and composition (10%). Structure and function (but not composition) declined more when grazed by sheep and cattle together than sheep alone. Grazing reduced plant biomass (40%), animal richness (15%), and plant and animal abundance, and plant and litter cover (25%), but had no effect on plant richness nor soil function. The negative effects of grazing on plant biomass, plant cover, and soil function were more pronounced in drier environments. Grazing effects on plant and animal richness and composition were constant, or even declined, with increasing aridity. Our study represents a comprehensive continental assessment of the implications of grazing for managing Australian rangelands. Grazing effects were largely negative, even at very low levels of grazing. Overall, our results suggest that livestock grazing in Australia is unlikely to produce positive outcomes for ecosystem structure, function, and composition or even as a blanket conservation tool unless reduction in specific response variables is an explicit management objective. PMID:27509764

  14. Biophysical interactions in fluvial ecosystems: effects of submerged aquatic macrophytes on hydro-morphological processes and ecosystem functioning

    NASA Astrophysics Data System (ADS)

    Cornacchia, Loreta; Davies, Grieg; Grabowski, Robert; van der Wal, Daphne; van de Koppel, Johan; Wharton, Geraldene; Bouma, Tjeerd

    2016-04-01

    Strong mutual interactions occur at the interface between biota and physical processes in biogeomorphic ecosystems, possibly resulting in self-organized spatial patterns. While these interactions and feedbacks have been increasingly studied in a wide range of landscapes previously, they are still poorly understood in lower energy fluvial systems. Consequently, their impact on the functioning of aquatic ecosystems is largely unknown. In this study we investigate the role of aquatic macrophytes as biological engineers of flow and sediment in lowland streams dominated by water crowfoot (Ranunculus spp.). Using field measurements from two annual growth cycles, we demonstrate that seasonally-changing macrophyte cover maintains relative constant flow rates, both within and between vegetation, despite temporal changes in channel flow discharge. By means of a mathematical model representing the interaction between hydrodynamics and vegetation dynamics, we reveal that scale-dependent feedbacks between plant growth and flow redistribution explain the influence of macrophytes on stabilizing flow rates. Our analysis reveals important implications for ecosystem functions. The creation of fast-flowing channels allows an adequate conveyance of water throughout the annual cycle; yet, patches also have a significant influence on sediment dynamics leading to heterogeneous habitats, thereby facilitating other species. As a last step we investigate the consequences on stream ecosystem functioning, by exploring the relationship between changes in macrophyte cover and the provision of different ecosystem functions (e.g. water conveyance, sediment trapping). Our results highlight that self-organization promotes the combination of multiple ecosystem functions through its effects on hydrological and morphological processes within biogeomorphic ecosystems.

  15. Foundation species loss affects vegetation structure more than ecosystem function in a northeastern USA forest.

    PubMed

    Orwig, David A; Barker Plotkin, Audrey A; Davidson, Eric A; Lux, Heidi; Savage, Kathleen E; Ellison, Aaron M

    2013-01-01

    Loss of foundation tree species rapidly alters ecological processes in forested ecosystems. Tsuga canadensis, an hypothesized foundation species of eastern North American forests, is declining throughout much of its range due to infestation by the nonnative insect Adelges tsugae and by removal through pre-emptive salvage logging. In replicate 0.81-ha plots, T. canadensis was cut and removed, or killed in place by girdling to simulate adelgid damage. Control plots included undisturbed hemlock and mid-successional hardwood stands that represent expected forest composition in 50-100 years. Vegetation richness, understory vegetation cover, soil carbon flux, and nitrogen cycling were measured for two years prior to, and five years following, application of experimental treatments. Litterfall and coarse woody debris (CWD), including snags, stumps, and fallen logs and branches, have been measured since treatments were applied. Overstory basal area was reduced 60%-70% in girdled and logged plots. Mean cover and richness did not change in hardwood or hemlock control plots but increased rapidly in girdled and logged plots. Following logging, litterfall immediately decreased then slowly increased, whereas in girdled plots, there was a short pulse of hemlock litterfall as trees died. CWD volume remained relatively constant throughout but was 3-4× higher in logged plots. Logging and girdling resulted in small, short-term changes in ecosystem dynamics due to rapid regrowth of vegetation but in general, interannual variability exceeded differences among treatments. Soil carbon flux in girdled plots showed the strongest response: 35% lower than controls after three years and slowly increasing thereafter. Ammonium availability increased immediately after logging and two years after girdling, due to increased light and soil temperatures and nutrient pulses from leaf-fall and reduced uptake following tree death. The results from this study illuminate ecological processes underlying

  16. Biogeochemical processes driving mercury cycling in estuarine ecosystems

    NASA Astrophysics Data System (ADS)

    Schartup, A. T.

    2015-12-01

    Mercury (Hg) is a naturally occurring element that has been enriched in the environment through human activities, particularly in the coastal zone. Bioaccumulation of methylmercury (MeHg) in marine fishposes health risks for fish-consuming populations and is a worldwide health concern. A broader understanding of major environmental processes controlling Hg cycling and MeHg production and bioaccumulation in estuaries is therefore needed. Recent fieldwork and modeling show diverse sources of MeHg production in estuaries. We present geochemical modeling results for Hg and MeHg acrossmultiple estuaries with contrasting physical, chemical and biological characteristics. We report new measurements of water column and sediment mercury speciation and methylation data from the subarctic (Lake Melville, Labrador Canada) and temperate latitudes (Long Island Sound, Delaware Bay, Chesapeake Bay). We find that benthic sediment is a relatively small source of MeHg to the water column in all systems. Water column methylation drives MeHg levels in Lake Melville, whereas in more impacted shallow systems such as Chesapeake Bay and Long Island Sound, external inputs and sediment resuspension are more dominant. All systems are a net source of MeHg to the ocean through tidal exchange. In light of these inter-system differences, we will evaluate timescales of coastal ecosystem responses to changes in Hg loading that can help predict potential responses to future perturbations.

  17. Glyphosate herbicide affects belowground interactions between earthworms and symbiotic mycorrhizal fungi in a model ecosystem

    PubMed Central

    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

  18. Glyphosate herbicide affects belowground interactions between earthworms and symbiotic mycorrhizal fungi in a model ecosystem

    NASA Astrophysics Data System (ADS)

    Zaller, Johann G.; Heigl, Florian; Ruess, Liliane; Grabmaier, Andrea

    2014-07-01

    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.

  19. Glyphosate herbicide affects belowground interactions between earthworms and symbiotic mycorrhizal fungi in a model ecosystem.

    PubMed

    Zaller, Johann G; Heigl, Florian; Ruess, Liliane; Grabmaier, Andrea

    2014-07-09

    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.

  20. Effects of Consumer Interactions on Benthic Resources and Ecosystem Processes in a Neotropical Stream

    PubMed Central

    Marshall, Michael C.; Binderup, Andrew J.; Zandonà, Eugenia; Goutte, Sandra; Bassar, Ronald D.; El-Sabaawi, Rana W.; Thomas, Steven A.; Flecker, Alexander S.; Kilham, Susan S.; Reznick, David N.; Pringle, Cathy M.

    2012-01-01

    The effect of consumers on their resources has been demonstrated in many systems but is often confounded by trophic interactions with other consumers. Consumers may also have behavioral and life history adaptations to each other and to co-occurring predators that may additionally modulate their particular roles in ecosystems. We experimentally excluded large consumers from tile periphyton, leaves and natural benthic substrata using submerged electrified frames in three stream reaches with overlapping consumer assemblages in Trinidad, West Indies. Concurrently, we assessed visits to (non-electrified) control frames by the three most common large consumers–primarily insectivorous killifish (Rivulus hartii), omnivorous guppies (Poecilia reticulata) and omnivorous crabs (Eudaniela garmani). Consumers caused the greatest decrease in final chlorophyll a biomass and accrual rates the most in the downstream reach containing all three focal consumers in the presence of fish predators. Consumers also caused the greatest increase in leaf decay rates in the upstream reach containing only killifish and crabs. In the downstream reach where guppies co-occur with predators, we found significantly lower benthic invertebrate biomass in control relative to exclosure treatments than the midstream reach where guppies occur in the absence of predators. These data suggest that differences in guppy foraging, potentially driven by differences in their life history phenotype, may affect ecosystem structure and processes as much as their presence or absence and that interactions among consumers may further mediate their effects in these stream ecosystems. PMID:23028865

  1. Effects of consumer interactions on benthic resources and ecosystem processes in a neotropical stream.

    PubMed

    Marshall, Michael C; Binderup, Andrew J; Zandonà, Eugenia; Goutte, Sandra; Bassar, Ronald D; El-Sabaawi, Rana W; Thomas, Steven A; Flecker, Alexander S; Kilham, Susan S; Reznick, David N; Pringle, Cathy M

    2012-01-01

    The effect of consumers on their resources has been demonstrated in many systems but is often confounded by trophic interactions with other consumers. Consumers may also have behavioral and life history adaptations to each other and to co-occurring predators that may additionally modulate their particular roles in ecosystems. We experimentally excluded large consumers from tile periphyton, leaves and natural benthic substrata using submerged electrified frames in three stream reaches with overlapping consumer assemblages in Trinidad, West Indies. Concurrently, we assessed visits to (non-electrified) control frames by the three most common large consumers-primarily insectivorous killifish (Rivulus hartii), omnivorous guppies (Poecilia reticulata) and omnivorous crabs (Eudaniela garmani). Consumers caused the greatest decrease in final chlorophyll a biomass and accrual rates the most in the downstream reach containing all three focal consumers in the presence of fish predators. Consumers also caused the greatest increase in leaf decay rates in the upstream reach containing only killifish and crabs. In the downstream reach where guppies co-occur with predators, we found significantly lower benthic invertebrate biomass in control relative to exclosure treatments than the midstream reach where guppies occur in the absence of predators. These data suggest that differences in guppy foraging, potentially driven by differences in their life history phenotype, may affect ecosystem structure and processes as much as their presence or absence and that interactions among consumers may further mediate their effects in these stream ecosystems. PMID:23028865

  2. Heat Transfer Processes for the Thermal Energy Balance of Organisms. Physical Processes in Terrestrial and Aquatic Ecosystems, Transport Processes.

    ERIC Educational Resources Information Center

    Stevenson, R. D.

    This module is part of a series 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 module describes heat transfer processes involved in the exchange of heat…

  3. Urbanization affects stream ecosystem function by altering hydrology, chemistry, and biotic richness.

    PubMed

    Chadwick, Michael A; Dobberfuhl, Dean R; Benke, Arthur C; Huryn, Alexander D; Suberkropp, Keller; Thiele, John E

    2006-10-01

    Catchment urbanization can alter physical, chemical, and biological attributes of stream ecosystems. In particular, changes in land use may affect the dynamics of organic matter decomposition, a measure of ecosystem function. We examined leaf-litter decomposition in 18 tributaries of the St. Johns River, Florida, USA. Land use in all 18 catchments ranged from 0% to 93% urban which translated to 0% to 66% total impervious area (TIA). Using a litter-bag technique, we measured mass loss, fungal biomass, and macroinvertebrate biomass for two leaf species (red maple [Acer rubrum] and sweetgum [Liquidambar styraciflua]). Rates of litter mass loss, which ranged from 0.01 to 0.05 per day for red maple and 0.006 to 0.018 per day for sweetgum, increased with impervious catchment area to levels of approximately 30-40% TIA and then decreased as impervious catchment area exceeded 40% TIA. Fungal biomass was also highest in streams draining catchments with intermediate levels of TIA. Macroinvertebrate biomass ranged from 17 to 354 mg/bag for red maple and from 15 to 399 mg/bag for sweetgum. Snail biomass and snail and total invertebrate richness were strongly related to breakdown rates among streams regardless of leaf species. Land-use and physical, chemical, and biological variables were highly intercorrelated. Principal-components analysis was therefore used to reduce the variables into several orthogonal axes. Using stepwise regression, we found that flow regime, snail biomass, snail and total invertebrate richness, and metal and nutrient content (which varied in a nonlinear manner with impervious surface area) were likely factors affecting litter breakdown rates in these streams.

  4. Occurrence of perchloroethylene in surface water and fish in a river ecosystem affected by groundwater contamination.

    PubMed

    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. Guidelines, processes and tools for coastal ecosystem restoration, with examples from the United States

    SciTech Connect

    Thom, Ronald M.; Diefenderfer, Heida L.; Adkins, Jeffery E.; Judd, Chaeli; Anderson, Michael G.; Buenau, Kate E.; Borde, Amy B.; Johnson, Gary E.

    2011-02-01

    This paper presents a systematic approach to coastal restoration projects in five phases: planning, implementation, performance assessment, adaptive management, and dissemination of results. Twenty features of the iterative planning process are synthesized. The planning process starts with a vision, a description of the ecosystem and landscape, and goals. A conceptual model and planning objectives are developed, a site is selected using prioritization techniques, and numerical models contribute to preliminary designs as needed. Performance criteria and reference sites are selected and the monitoring program is designed. The monitoring program is emphasized as a tool to assess project performance and identify problems affecting progression toward project goals, in an adaptive management framework. Key approaches to aspects of the monitoring program are reviewed and detailed with project examples. Within the planning process, cost analysis involves budgeting, scheduling, and financing. Finally, documentation is peer reviewed prior to making construction plans and final costing.

  6. Physical processes mediating climate change impacts on regional sea ecosystems

    NASA Astrophysics Data System (ADS)

    Holt, J.; Schrum, C.; Cannaby, H.; Daewel, U.; Allen, I.; Artioli, Y.; Bopp, L.; Butenschon, M.; Fach, B. A.; Harle, J.; Pushpadas, D.; Salihoglu, B.; Wakelin, S.

    2014-02-01

    Regional seas are exceptionally vulnerable to climate change, yet are the most directly societally important regions of the marine environment. The combination of widely varying conditions of mixing, forcing, geography (coastline and bathymetry) and exposure to the open-ocean makes these seas subject to a wide range of physical processes that mediates how large scale climate change impacts on these seas' ecosystems. In this paper we explore these physical processes and their biophysical interactions, and the effects of atmospheric, oceanic and terrestrial change on them. Our aim is to elucidate the controlling dynamical processes and how these vary between and within regional seas. We focus on primary production and consider the potential climatic impacts: on long term changes in elemental budgets, on seasonal and mesoscale processes that control phytoplankton's exposure to light and nutrients, and briefly on direct temperature response. We draw examples from the MEECE FP7 project and five regional models systems using ECOSMO, POLCOMS-ERSEM and BIMS_ECO. These cover the Barents Sea, Black Sea, Baltic Sea, North Sea, Celtic Seas, and a region of the Northeast Atlantic, using a common global ocean-atmosphere model as forcing. We consider a common analysis approach, and a more detailed analysis of the POLCOMS-ERSEM model. Comparing projections for the end of the 21st century with mean present day conditions, these simulations generally show an increase in seasonal and permanent stratification (where present). However, the first order (low- and mid-latitude) effect in the open ocean projections of increased permanent stratification leading to reduced nutrient levels, and so to reduced primary production, is largely absent, except in the NE Atlantic. Instead, results show a highly heterogeneous picture of positive and negative change arising from the varying mixing and circulation conditions. Even in the two highly stratified, deep water seas (Black and Baltic Seas) the

  7. Assessing simulated ecosystem processes for climate variability research at Glacier National Park, USA

    USGS Publications Warehouse

    White, J.D.; Running, S.W.; Thornton, P.E.; Keane, R.E.; Ryan, K.C.; Fagre, D.B.; Key, C.H.

    1998-01-01

    Glacier National Park served as a test site for ecosystem analyses than involved a suite of integrated models embedded within a geographic information system. The goal of the exercise was to provide managers with maps that could illustrate probable shifts in vegetation, net primary production (NPP), and hydrologic responses associated with two selected climatic scenarios. The climatic scenarios were (a) a recent 12-yr record of weather data, and (b) a reconstituted set that sequentially introduced in repeated 3-yr intervals wetter-cooler, drier-warmer, and typical conditions. To extrapolate the implications of changes in ecosystem processes and resulting growth and distribution of vegetation and snowpack, the model incorporated geographic data. With underlying digital elevation maps, soil depth and texture, extrapolated climate, and current information on vegetation types and satellite-derived estimates of a leaf area indices, simulations were extended to envision how the park might look after 120 yr. The predictions of change included underlying processes affecting the availability of water and nitrogen. Considerable field data were acquired to compare with model predictions under current climatic conditions. In general, the integrated landscape models of ecosystem processes had good agreement with measured NPP, snowpack, and streamflow, but the exercise revealed the difficulty and necessity of averaging point measurements across landscapes to achieve comparable results with modeled values. Under the extremely variable climate scenario significant changes in vegetation composition and growth as well as hydrologic responses were predicted across the park. In particular, a general rise in both the upper and lower limits of treeline was predicted. These shifts would probably occur along with a variety of disturbances (fire, insect, and disease outbreaks) as predictions of physiological stress (water, nutrients, light) altered competitive relations and hydrologic

  8. Ecosystem services: developing sustainable management paradigms based on wetland functions and processes

    USGS Publications Warehouse

    Euliss, Ned H.; Mushet, David M.; Smith, Loren M.; Conner, William H.; Burkett, Virginia R.; Wilcox, Douglas A.; Hester, Mark W.; Zheng, Haochi

    2013-01-01

    In the late nineteenth century and twentieth century, there was considerable interest and activity to develop the United States for agricultural, mining, and many other purposes to improve the quality of human life standards and prosperity. Most of the work to support this development was focused along disciplinary lines with little attention focused on ecosystem service trade-offs or synergisms, especially those that transcended boundaries of scientific disciplines and specific interest groups. Concurrently, human population size has increased substantially and its use of ecosystem services has increased more than five-fold over just the past century. Consequently, the contemporary landscape has been highly modified for human use, leaving behind a fragmented landscape where basic ecosystem functions and processes have been broadly altered. Over this period, climate change also interacted with other anthropogenic effects, resulting in modern environmental problems having a complexity that is without historical precedent. The challenge before the scientific community is to develop new science paradigms that integrate relevant scientific disciplines to properly frame and evaluate modern environmental problems in a systems-type approach to better inform the decision-making process. Wetland science is a relatively new discipline that grew out of the conservation movement of the early twentieth century. In the United States, most of the conservation attention in the earlier days was on wildlife, but a growing human awareness of the importance of the environment led to the passage of the National Environmental Policy Act in 1969. Concurrently, there was a broadening interest in conservation science, and the scientific study of wetlands gradually gained acceptance as a scientific discipline. Pioneering wetland scientists became formally organized when they formed The Society of Wetland Scientists in 1980 and established a publication outlet to share wetland research

  9. Linking Belowground Plant Traits With Ecosystem Processes: A Multi-Biome Perspective

    NASA Astrophysics Data System (ADS)

    Iversen, C. M.; Norby, R. J.; Childs, J.; McCormack, M. L.; Walker, A. P.; Hanson, P. J.; Warren, J.; Sloan, V. L.; Sullivan, P. F.; Wullschleger, S.; Powell, A. S.

    2015-12-01

    Fine plant roots are short-lived, narrow-diameter roots that play an important role in ecosystem carbon, water, and nutrient cycling in biomes ranging from the tundra to the tropics. Root ecologists make measurements at a millimeter scale to answer a question with global implications: In response to a changing climate, how do fine roots modulate the exchange of carbon between soils and the atmosphere and how will this response affect our future climate? In a Free-Air CO2 Enrichment experiment in Oak Ridge, TN, elevated [CO2] caused fine roots to dive deeper into the soil profile in search of limiting nitrogen, which led to increased soil C storage in deep soils. In contrast, the fine roots of trees and shrubs in an ombrotrophic bog are constrained to nutrient-poor, oxic soils above the average summer water table depth, though this may change with warmer, drier conditions. Tundra plant species are similarly constrained to surface organic soils by permafrost or waterlogged soils, but have many adaptations that alter ecosystem C fluxes, including aerenchyma that oxygenate the rhizosphere but also allow direct methane flux to the atmosphere. FRED, a global root trait database, will allow terrestrial biosphere models to represent the complexity of root traits across the globe, informing both model representation of ecosystem C and nutrient fluxes, but also the gaps where measurements are needed on plant-soil interactions (for example, in the tropical biome). While the complexity of mm-scale measurements may never have a place in large-scale global models, close collaboration between empiricists and modelers can help to guide the scaling of important, yet small-scale, processes to quantify their important roles in larger-scale ecosystem fluxes.

  10. Grazing-induced losses of biodiversity affect the transpiration of an arid ecosystem.

    PubMed

    Verón, Santiago R; Paruelo, José M; Oesterheld, Martín

    2011-02-01

    Degradation processes often lead to species loss. Such losses would impact on ecosystem functioning depending on the extinction order and the functional and structural aspects of species. For the Patagonian arid steppe, we used a simulation model to study the effects of species loss on the rate and variability (i.e. stability) of transpiration as a key attribute of ecosystem functioning. We addressed (1) the differences between the overgrazing extinction order and other potential orders, and (2) the role of biomass abundance, biomass distribution, and functional diversity on the effect of species loss due to overgrazing. We considered a community composed of ten species which were assigned an order of extinction due to overgrazing based on their preference by livestock. We performed four model simulations to test for overgrazing effects through different combinations of species loss, and reductions of biomass and functional diversity. In general, transpiration rate and variability were positively associated to species richness and remained fairly constant until half the species were lost by overgrazing. The extinction order by overgrazing was the most conservative of all possible orders. The amount of biomass was more important than functional diversity in accounting for the impacts of species richness on transpiration. Our results suggest that, to prevent Patagonian steppes from shifting to stable, low-production systems (by overgrazing), maintaining community biomass is more important than preserving species richness or species functional diversity. PMID:20865282

  11. Linking trajectories of land change, land degradation processes and ecosystem services.

    PubMed

    Smiraglia, D; Ceccarelli, T; Bajocco, S; Salvati, L; Perini, L

    2016-05-01

    Land Degradation (LD) is a complex phenomenon resulting in a progressive reduction in the capacity of providing ecosystem services (ES). Landscape transformations promoting an unsustainable use of land often reveal latent processes of LD. An evaluation carried out in respect to the different ecosystem services is nowadays regarded as the most appropriate approach for assessing the effects of LD. The aim of this study is to develop an evaluation framework for identifying the linkages between land changes, LD processes and ES and suggesting Sustainable Land Management (SLM) options suited to reverse (or mitigate) LD impact. A SWOT analysis was carried out with the aim to identify internal and external factors that are favorable (or unfavorable) to achieve the proposed SLM actions. The study areas are the Fortore valley and the Valpadana, in Italy. The main trajectory identified for the Fortore valley is related to land abandonment due to population aging and the progressive emigration started in the 1950s. The most relevant LD processes are soil erosion and geomorphological instability, affecting regulating services such as natural hazard and erosion control. SLM options should consider interventions to contrast geomorphological instability, the promotion of climate smart agriculture and of typical products, and an efficient water resources management. The main trajectories identified for Valpadana are related to urban expansion and farmland abandonment and, as a consequence, land take due to anthropogenic pressure and woodland expansion as the main LD process. The reduction of food production was identified as the most relevant provisioning service affected. SLM should envisage best practices finalized to water saving and soil consumption reduction: efficient irrigation solutions, climate smart agriculture and zero sealing practices. This study highlights the diagnostic value of the suggested approach where LD processes are elicited from land change trajectories

  12. Linking trajectories of land change, land degradation processes and ecosystem services.

    PubMed

    Smiraglia, D; Ceccarelli, T; Bajocco, S; Salvati, L; Perini, L

    2016-05-01

    Land Degradation (LD) is a complex phenomenon resulting in a progressive reduction in the capacity of providing ecosystem services (ES). Landscape transformations promoting an unsustainable use of land often reveal latent processes of LD. An evaluation carried out in respect to the different ecosystem services is nowadays regarded as the most appropriate approach for assessing the effects of LD. The aim of this study is to develop an evaluation framework for identifying the linkages between land changes, LD processes and ES and suggesting Sustainable Land Management (SLM) options suited to reverse (or mitigate) LD impact. A SWOT analysis was carried out with the aim to identify internal and external factors that are favorable (or unfavorable) to achieve the proposed SLM actions. The study areas are the Fortore valley and the Valpadana, in Italy. The main trajectory identified for the Fortore valley is related to land abandonment due to population aging and the progressive emigration started in the 1950s. The most relevant LD processes are soil erosion and geomorphological instability, affecting regulating services such as natural hazard and erosion control. SLM options should consider interventions to contrast geomorphological instability, the promotion of climate smart agriculture and of typical products, and an efficient water resources management. The main trajectories identified for Valpadana are related to urban expansion and farmland abandonment and, as a consequence, land take due to anthropogenic pressure and woodland expansion as the main LD process. The reduction of food production was identified as the most relevant provisioning service affected. SLM should envisage best practices finalized to water saving and soil consumption reduction: efficient irrigation solutions, climate smart agriculture and zero sealing practices. This study highlights the diagnostic value of the suggested approach where LD processes are elicited from land change trajectories

  13. Units of nature or processes across scales? The ecosystem concept at age 75.

    PubMed

    Currie, William S

    2011-04-01

    The ecosystem has served as a central organizational concept in ecology for nearly a half century and continues to evolve. As a level in the biotic hierarchy, ecosystems are often viewed as ecological communities integrated with their abiotic environments. This has always been imperfect because of a mismatch of scales between communities and ecosystem processes as they are made operational for field study. Complexity theory has long been forecasted to provide a renewed foundation for ecosystem theory but has been slow to do so. Partly this has arisen from a difficulty in translating theoretical tenets into operational terms for testing in field studies. Ecosystem science has become an important applied science for studying global change and human environmental impacts. Vigorous and important directions in the study of ecosystems today include a growing focus on human-dominated landscapes and development of the concept of ecosystem services for human resource supply and well-being. Today, terrestrial ecosystems are viewed less as well-defined entities or as a level in the biotic hierarchy. Instead, ecosystem processes are being increasingly viewed as the elements in a hierarchy. These occur alongside landscape processes and socioeconomic processes, which combine to form coupled social-ecological systems across a range of scales.

  14. How stock of origin affects performance of individuals across a meta-ecosystem: an example from sockeye salmon.

    PubMed

    Griffiths, Jennifer R; Schindler, Daniel E; Seeb, Lisa W

    2013-01-01

    Connectivity among diverse habitats can buffer populations from adverse environmental conditions, influence the functioning of meta-ecosystems, and ultimately affect the reliability of ecosystem services. This stabilizing effect on populations is proposed to derive from complementarity in growth and survival conditions experienced by individuals in the different habitats that comprise meta-ecosystems. Here we use the fine scale differentiation of salmon populations between diverse lake habitats to assess how rearing habitat and stock of origin affect the body condition of juvenile sockeye salmon. We use genetic markers (single nucleotide polymorphisms) to assign individuals of unknown origin to stock group and in turn characterize ecologically relevant attributes across habitats and stocks. Our analyses show that the body condition of juvenile salmon is related to the productivity of alternative habitats across the watershed, irrespective of their stock of origin. Emigrants and residents with genetic origins in the high productivity lake were also differentiated by their body condition, poor and high respectively. These emigrants represented a substantial proportion of juvenile sockeye salmon rearing in the lower productivity lake habitat. Despite emigrants originating from the more productive lake, they did not differ in body condition from the individuals spawned in the lower productivity, recipient habitat. Genetic tools allowed us to assess the performance of different stocks groups across the diverse habitats comprising their meta-ecosystem. The ability to characterize the ecological consequences of meta-ecosystem connectivity can help develop strategies to protect and restore ecosystems and the services they provide to humans. PMID:23505539

  15. How Stock of Origin Affects Performance of Individuals across a Meta-Ecosystem: An Example from Sockeye Salmon

    PubMed Central

    Griffiths, Jennifer R.; Schindler, Daniel E.; Seeb, Lisa W.

    2013-01-01

    Connectivity among diverse habitats can buffer populations from adverse environmental conditions, influence the functioning of meta-ecosystems, and ultimately affect the reliability of ecosystem services. This stabilizing effect on populations is proposed to derive from complementarity in growth and survival conditions experienced by individuals in the different habitats that comprise meta-ecosystems. Here we use the fine scale differentiation of salmon populations between diverse lake habitats to assess how rearing habitat and stock of origin affect the body condition of juvenile sockeye salmon. We use genetic markers (single nucleotide polymorphisms) to assign individuals of unknown origin to stock group and in turn characterize ecologically relevant attributes across habitats and stocks. Our analyses show that the body condition of juvenile salmon is related to the productivity of alternative habitats across the watershed, irrespective of their stock of origin. Emigrants and residents with genetic origins in the high productivity lake were also differentiated by their body condition, poor and high respectively. These emigrants represented a substantial proportion of juvenile sockeye salmon rearing in the lower productivity lake habitat. Despite emigrants originating from the more productive lake, they did not differ in body condition from the individuals spawned in the lower productivity, recipient habitat. Genetic tools allowed us to assess the performance of different stocks groups across the diverse habitats comprising their meta-ecosystem. The ability to characterize the ecological consequences of meta-ecosystem connectivity can help develop strategies to protect and restore ecosystems and the services they provide to humans. PMID:23505539

  16. Building an Innovation Ecosystem: Process, Culture and Competencies

    ERIC Educational Resources Information Center

    Smith, Kenneth R.

    2006-01-01

    For almost three decades we have optimized our organizations for efficiency and quality. We now look to innovation as the source of competitive advantage--for individuals, for organizations and for society. This paper examines the three components of an innovation ecosystem and their implications for corporations, universities and public policy.…

  17. Discontinuity in the responses of ecosystem processes and multifunctionality to altered soil community composition

    PubMed Central

    Bradford, Mark A.; Wood, Stephen A.; Bardgett, Richard D.; Black, Helaina I. J.; Bonkowski, Michael; Eggers, Till; Grayston, Susan J.; Kandeler, Ellen; Manning, Peter; Setälä, Heikki; Jones, T. Hefin

    2014-01-01

    Ecosystem management policies increasingly emphasize provision of multiple, as opposed to single, ecosystem services. Management for such “multifunctionality” has stimulated research into the role that biodiversity plays in providing desired rates of multiple ecosystem processes. Positive effects of biodiversity on indices of multifunctionality are consistently found, primarily because species that are redundant for one ecosystem process under a given set of environmental conditions play a distinct role under different conditions or in the provision of another ecosystem process. Here we show that the positive effects of diversity (specifically community composition) on multifunctionality indices can also arise from a statistical fallacy analogous to Simpson’s paradox (where aggregating data obscures causal relationships). We manipulated soil faunal community composition in combination with nitrogen fertilization of model grassland ecosystems and repeatedly measured five ecosystem processes related to plant productivity, carbon storage, and nutrient turnover. We calculated three common multifunctionality indices based on these processes and found that the functional complexity of the soil communities had a consistent positive effect on the indices. However, only two of the five ecosystem processes also responded positively to increasing complexity, whereas the other three responded neutrally or negatively. Furthermore, none of the individual processes responded to both the complexity and the nitrogen manipulations in a manner consistent with the indices. Our data show that multifunctionality indices can obscure relationships that exist between communities and key ecosystem processes, leading us to question their use in advancing theoretical understanding—and in management decisions—about how biodiversity is related to the provision of multiple ecosystem services. PMID:25246582

  18. Discontinuity in the responses of ecosystem processes and multifunctionality to altered soil community composition.

    PubMed

    Bradford, Mark A; Wood, Stephen A; Bardgett, Richard D; Black, Helaina I J; Bonkowski, Michael; Eggers, Till; Grayston, Susan J; Kandeler, Ellen; Manning, Peter; Setälä, Heikki; Jones, T Hefin

    2014-10-01

    Ecosystem management policies increasingly emphasize provision of multiple, as opposed to single, ecosystem services. Management for such "multifunctionality" has stimulated research into the role that biodiversity plays in providing desired rates of multiple ecosystem processes. Positive effects of biodiversity on indices of multifunctionality are consistently found, primarily because species that are redundant for one ecosystem process under a given set of environmental conditions play a distinct role under different conditions or in the provision of another ecosystem process. Here we show that the positive effects of diversity (specifically community composition) on multifunctionality indices can also arise from a statistical fallacy analogous to Simpson's paradox (where aggregating data obscures causal relationships). We manipulated soil faunal community composition in combination with nitrogen fertilization of model grassland ecosystems and repeatedly measured five ecosystem processes related to plant productivity, carbon storage, and nutrient turnover. We calculated three common multifunctionality indices based on these processes and found that the functional complexity of the soil communities had a consistent positive effect on the indices. However, only two of the five ecosystem processes also responded positively to increasing complexity, whereas the other three responded neutrally or negatively. Furthermore, none of the individual processes responded to both the complexity and the nitrogen manipulations in a manner consistent with the indices. Our data show that multifunctionality indices can obscure relationships that exist between communities and key ecosystem processes, leading us to question their use in advancing theoretical understanding--and in management decisions--about how biodiversity is related to the provision of multiple ecosystem services.

  19. Food web pathway determines how selenium affects aquatic ecosystems: a San Francisco Bay case study.

    PubMed

    Stewart, A Robin; Luoma, Samuel N; Schlekat, Christian E; Doblin, Martina A; Hieb, Kathryn A

    2004-09-01

    Chemical contaminants disrupt ecosystems, but specific effects may be under-appreciated when poorly known processes such as uptake mechanisms, uptake via diet, food preferences, and food web dynamics are influential. Here we show that a combination of food web structure and the physiology of trace element accumulation explain why some species in San Francisco Bay are threatened by a relatively low level of selenium contamination and some are not. Bivalves and crustacean zooplankton form the base of two dominant food webs in estuaries. The dominant bivalve Potamocorbula amurensis has a 10-fold slower rate constant of loss for selenium than do common crustaceans such as copepods and the mysid Neomysis mercedis (rate constant of loss, ke = 0.025, 0.155, and 0.25 d(-1), respectively). The result is much higher selenium concentrations in the bivalve than in the crustaceans. Stable isotope analyses show that this difference is propagated up the respective food webs in San Francisco Bay. Several predators of bivalves have tissue concentrations of selenium that exceed thresholds thought to be associated with teratogenesis or reproductive failure (liver Se >15 microg g(-1) dry weight). Deformities typical of selenium-induced teratogenesis were observed in one of these species. Concentrations of selenium in tissues of predators of zooplankton are less than the thresholds. Basic physiological and ecological processes can drive wide differences in exposure and effects among species, but such processes are rarely considered in traditional evaluations of contaminant impacts. PMID:15461158

  20. Food web pathway determines how selenium affects aquatic ecosystems: A San francisco Bay case study

    USGS Publications Warehouse

    Stewart, A.R.; Luoma, S.N.; Schlekat, C.E.; Doblin, M.A.; Hieb, K.A.

    2004-01-01

    Chemical contaminants disrupt ecosystems, but specific effects may be under-appreciated when poorly known processes such as uptake mechanisms, uptake via diet, food preferences, and food web dynamics are influential. Here we show that a combination of food web structure and the physiology of trace element accumulation explain why some species in San Francisco Bay are threatened by a relatively low level of selenium contamination and some are not. Bivalves and crustacean Zooplankton form the base of two dominant food webs in estuaries. The dominant bivalve Potamocorbula amurensis has a 10-fold slower rate constant of loss for selenium than do common crustaceans such as copepods and the mysid Neomysis mercedis (rate constant of loss, ke = 0.025, 0.155, and 0.25 d-1, respectively). The result is much higher selenium concentrations in the bivalve than in the crustaceans. Stable isotope analyses show that this difference is propagated up the respective food webs in San Francisco Bay. Several predators of bivalves have tissue concentrations of selenium that exceed thresholds thought to be associated with teratogenesis or reproductive failure (liver Se > 15 ??g g-1 dry weight). Deformities typical of selenium-induced teratogenesis were observed in one of these species. Concentrations of selenium in tissues of predators of Zooplankton are less than the thresholds. Basic physiological and ecological processes can drive wide differences in exposure and effects among species, but such processes are rarely considered in traditional evaluations of contaminant impacts.

  1. Municipal sludge metal contamination of old-field ecosystems: Do liming and tilling affect remediation

    SciTech Connect

    Benninger-Truax, M.; Taylor, D.H. . Dept. of Zoology)

    1993-10-01

    Mechanisms of ecosystem recovery following 11 years of sewage sludge disposal were addressed by examining the effects of tilling and/or liming on soil chemistry and the heavy metal (Cd, Cu, Pb, and Zn) concentrations in soil, earthworms, vegetation, spiders, and crickets. In 1989 and 1990, subplots in each of three former 0.1-ha, long-term treatments (sludge, fertilizer, and control) were either unmanipulated or manipulated via tilling and/or liming. Liming significantly increased the pH of soil from the long-term sludge and fertilizer plots, and the combination of tilling and liming affected the heavy metal concentrations in earthworms, as lower concentrations of Cd, Cu, Pb, and Zn were found in earthworms collected from subplots that had been both tilled and limed. However, most observed significant differences in heavy metal concentrations reflected the long-term treatments, as heavy metal concentrations tended to be greater in the soil and biota collected from sludge-treated plots. Thus, heavy metals remained in the soil in forms available to the biota, regardless of the cessation of sludge application or subplot manipulations (liming and/or tilling) for two years following cessation of sludge application.

  2. Quantifying causal mechanisms to determine how protected areas affect poverty through changes in ecosystem services and infrastructure.

    PubMed

    Ferraro, Paul J; Hanauer, Merlin M

    2014-03-18

    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.

  3. Quantifying causal mechanisms to determine how protected areas affect poverty through changes in ecosystem services and infrastructure.

    PubMed

    Ferraro, Paul J; Hanauer, Merlin M

    2014-03-18

    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

  4. The functional value of Caribbean coral reef, seagrass and mangrove habitats to ecosystem processes.

    PubMed

    Harborne, Alastair R; Mumby, Peter J; Micheli, Fiorenza; Perry, Christopher T; Dahlgren, Craig P; Holmes, Katherine E; Brumbaugh, Daniel R

    2006-01-01

    Caribbean coral reef habitats, seagrass beds and mangroves provide important goods and services both individually and through functional linkages. A range of anthropogenic factors are threatening the ecological and economic importance of these habitats and it is vital to understand how ecosystem processes vary across seascapes. A greater understanding of processes will facilitate further insight into the effects of disturbances and assist with assessing management options. Despite the need to study processes across whole seascapes, few spatially explicit ecosystem-scale assessments exist. We review the empirical literature to examine the role of different habitat types for a range of processes. The importance of each of 10 generic habitats to each process is defined as its "functional value" (none, low, medium or high), quantitatively derived from published data wherever possible and summarised in a single figure. This summary represents the first time the importance of habitats across an entire Caribbean seascape has been assessed for a range of processes. Furthermore, we review the susceptibility of each habitat to disturbances to investigate spatial patterns that might affect functional values. Habitat types are considered at the scale discriminated by remotely-sensed imagery and we envisage that functional values can be combined with habitat maps to provide spatially explicit information on processes across ecosystems. We provide examples of mapping the functional values of habitats for populations of three commercially important species. The resulting data layers were then used to generate seascape-scale assessments of "hot spots" of functional value that might be considered priorities for conservation. We also provide an example of how the literature reviewed here can be used to parameterise a habitat-specific model investigating reef resilience under different scenarios of herbivory. Finally, we use multidimensional scaling to provide a basic analysis of the

  5. Dominance, Biomass and Extinction Resistance Determine the Consequences of Biodiversity Loss for Multiple Coastal Ecosystem Processes

    PubMed Central

    Davies, Thomas W.; Jenkins, Stuart R.; Kingham, Rachel; Kenworthy, Joseph; Hawkins, Stephen J.; Hiddink, Jan G.

    2011-01-01

    Key ecosystem processes such as carbon and nutrient cycling could be deteriorating as a result of biodiversity loss. However, currently we lack the ability to predict the consequences of realistic species loss on ecosystem processes. The aim of this study was to test whether species contributions to community biomass can be used as surrogate measures of their contribution to ecosystem processes. These were gross community productivity in a salt marsh plant assemblage and an intertidal macroalgae assemblage; community clearance of microalgae in sessile suspension feeding invertebrate assemblage; and nutrient uptake in an intertidal macroalgae assemblage. We conducted a series of biodiversity manipulations that represented realistic species extinction sequences in each of the three contrasting assemblages. Species were removed in a subtractive fashion so that biomass was allowed to vary with each species removal, and key ecosystem processes were measured at each stage of community disassembly. The functional contribution of species was directly proportional to their contribution to community biomass in a 1∶1 ratio, a relationship that was consistent across three contrasting marine ecosystems and three ecosystem processes. This suggests that the biomass contributed by a species to an assemblage can be used to approximately predict the proportional decline in an ecosystem process when that species is lost. Such predictions represent “worst case scenarios” because, over time, extinction resilient species can offset the loss of biomass associated with the extinction of competitors. We also modelled a “best case scenario” that accounts for compensatory responses by the extant species with the highest per capita contribution to ecosystem processes. These worst and best case scenarios could be used to predict the minimum and maximum species required to sustain threshold values of ecosystem processes in the future. PMID:22163297

  6. Dominance, biomass and extinction resistance determine the consequences of biodiversity loss for multiple coastal ecosystem processes.

    PubMed

    Davies, Thomas W; Jenkins, Stuart R; Kingham, Rachel; Kenworthy, Joseph; Hawkins, Stephen J; Hiddink, Jan G

    2011-01-01

    Key ecosystem processes such as carbon and nutrient cycling could be deteriorating as a result of biodiversity loss. However, currently we lack the ability to predict the consequences of realistic species loss on ecosystem processes. The aim of this study was to test whether species contributions to community biomass can be used as surrogate measures of their contribution to ecosystem processes. These were gross community productivity in a salt marsh plant assemblage and an intertidal macroalgae assemblage; community clearance of microalgae in sessile suspension feeding invertebrate assemblage; and nutrient uptake in an intertidal macroalgae assemblage. We conducted a series of biodiversity manipulations that represented realistic species extinction sequences in each of the three contrasting assemblages. Species were removed in a subtractive fashion so that biomass was allowed to vary with each species removal, and key ecosystem processes were measured at each stage of community disassembly. The functional contribution of species was directly proportional to their contribution to community biomass in a 1:1 ratio, a relationship that was consistent across three contrasting marine ecosystems and three ecosystem processes. This suggests that the biomass contributed by a species to an assemblage can be used to approximately predict the proportional decline in an ecosystem process when that species is lost. Such predictions represent "worst case scenarios" because, over time, extinction resilient species can offset the loss of biomass associated with the extinction of competitors. We also modelled a "best case scenario" that accounts for compensatory responses by the extant species with the highest per capita contribution to ecosystem processes. These worst and best case scenarios could be used to predict the minimum and maximum species required to sustain threshold values of ecosystem processes in the future. PMID:22163297

  7. Nitrogen and carbon cycling in a grassland community ecosystem as affected by elevated atmospheric CO2

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increasing global atmospheric CO2 concentration has led to concerns regarding its potential effects on terrestrial ecosystem and the long-term storage of C and N in soil. This study examined responses to elevated CO2 in a grass ecosystem invaded with a leguminous shrub Acacia farnesiana (L.) Willd (...

  8. Predicted climate change alters the indirect effect of predators on an ecosystem process.

    PubMed

    Lensing, Janet R; Wise, David H

    2006-10-17

    Changes in rainfall predicted to occur with global climate change will likely alter rates of leaf-litter decomposition through direct effects on primary decomposers. In a field experiment replicated at two sites, we show that altered rainfall may also change how cascading trophic interactions initiated by arthropod predators in the leaf litter indirectly influence litter decomposition. On the drier site there was no interaction between rainfall and the indirect effect of predators on decomposition. In contrast, on the moister site spiders accelerated the disappearance rate of deciduous leaf litter under low rainfall, but had no, or possibly a negative, indirect effect under high rainfall. Thus, changes resulting from the more intense hydrological cycle expected to occur with climate change will likely influence how predators indirectly affect an essential ecosystem process. PMID:17023538

  9. Dilution, Not Load, Affects Distractor Processing

    ERIC Educational Resources Information Center

    Wilson, Daryl E.; Muroi, Miya; MacLeod, Colin M.

    2011-01-01

    Lavie and Tsal (1994) proposed that spare attentional capacity is allocated involuntarily to the processing of irrelevant stimuli, thereby enabling interference. Under this view, when task demands increase, spare capacity should decrease and distractor interference should decrease. In support, Lavie and Cox (1997) found that increasing perceptual…

  10. Sound Affects the Speed of Visual Processing

    ERIC Educational Resources Information Center

    Keetels, Mirjam; Vroomen, Jean

    2011-01-01

    The authors examined the effects of a task-irrelevant sound on visual processing. Participants were presented with revolving clocks at or around central fixation and reported the hand position of a target clock at the time an exogenous cue (1 clock turning red) or an endogenous cue (a line pointing toward 1 of the clocks) was presented. A…

  11. Biochemical processes in sagebrush ecosystems: Interactions with terrain

    NASA Technical Reports Server (NTRS)

    Matson, P. (Principal Investigator); Reiners, W.; Strong, L.

    1985-01-01

    The objectives of a biogeochemical study of sagebrush ecosystems in Wyoming and their interactions with terrain are as follows: to describe the vegetational pattern on the landscape and elucidate controlling variables, to measure the soil properties and chemical cycling properties associated with the vegetation units, to associate soil properties with vegetation properties as measured on the ground, to develop remote sensing capabilities for vegetation and surface characteristics of the sagebrush landscape, to develop a system of sensing snow cover and indexing seasonal soil to moisture; and to develop relationships between temporal Thematic Mapper (TM) data and vegetation phenological state.

  12. Auditory motion affects visual biological motion processing.

    PubMed

    Brooks, A; van der Zwan, R; Billard, A; Petreska, B; Clarke, S; Blanke, O

    2007-02-01

    The processing of biological motion is a critical, everyday task performed with remarkable efficiency by human sensory systems. Interest in this ability has focused to a large extent on biological motion processing in the visual modality (see, for example, Cutting, J. E., Moore, C., & Morrison, R. (1988). Masking the motions of human gait. Perception and Psychophysics, 44(4), 339-347). In naturalistic settings, however, it is often the case that biological motion is defined by input to more than one sensory modality. For this reason, here in a series of experiments we investigate behavioural correlates of multisensory, in particular audiovisual, integration in the processing of biological motion cues. More specifically, using a new psychophysical paradigm we investigate the effect of suprathreshold auditory motion on perceptions of visually defined biological motion. Unlike data from previous studies investigating audiovisual integration in linear motion processing [Meyer, G. F. & Wuerger, S. M. (2001). Cross-modal integration of auditory and visual motion signals. Neuroreport, 12(11), 2557-2560; Wuerger, S. M., Hofbauer, M., & Meyer, G. F. (2003). The integration of auditory and motion signals at threshold. Perception and Psychophysics, 65(8), 1188-1196; Alais, D. & Burr, D. (2004). No direction-specific bimodal facilitation for audiovisual motion detection. Cognitive Brain Research, 19, 185-194], we report the existence of direction-selective effects: relative to control (stationary) auditory conditions, auditory motion in the same direction as the visually defined biological motion target increased its detectability, whereas auditory motion in the opposite direction had the inverse effect. Our data suggest these effects do not arise through general shifts in visuo-spatial attention, but instead are a consequence of motion-sensitive, direction-tuned integration mechanisms that are, if not unique to biological visual motion, at least not common to all types of

  13. Potential climate change impacts on temperate forest ecosystem processes

    USGS Publications Warehouse

    Peters, Emily B.; Wythers, Kirk R.; Zhang, Shuxia; Bradford, John B.; Reich, Peter B.

    2013-01-01

    Large changes in atmospheric CO2, temperature and precipitation are predicted by 2100, yet the long-term consequences for carbon, water, and nitrogen cycling in forests are poorly understood. We applied the PnET-CN ecosystem model to compare the long-term effects of changing climate and atmospheric CO2 on productivity, evapotranspiration, runoff, and net nitrogen mineralization in current Great Lakes forest types. We used two statistically downscaled climate projections, PCM B1 (warmer and wetter) and GFDL A1FI (hotter and drier), to represent two potential future climate and atmospheric CO2 scenarios. To separate the effects of climate and CO2, we ran PnET-CN including and excluding the CO2 routine. Our results suggest that, with rising CO2 and without changes in forest type, average regional productivity could increase from 67% to 142%, changes in evapotranspiration could range from –3% to +6%, runoff could increase from 2% to 22%, and net N mineralization could increase 10% to 12%. Ecosystem responses varied geographically and by forest type. Increased productivity was almost entirely driven by CO2 fertilization effects, rather than by temperature or precipitation (model runs holding CO2 constant showed stable or declining productivity). The relative importance of edaphic and climatic spatial drivers of productivity varied over time, suggesting that productivity in Great Lakes forests may switch from being temperature to water limited by the end of the century.

  14. Large-scale regional comparisons of ecosystem processes: Methods and approaches

    NASA Astrophysics Data System (ADS)

    Legendre, Louis; Niquil, Nathalie

    2013-01-01

    Large-scale regional marine ecosystems can be compared for various processes that include their structure and biodiversity, functioning, services, and effects on biogeochemical processes. The comparisons can proceed from data up, or from conceptual models down, or from a combination of models and data. This study proposes a typology of methods and approaches that are currently used, or could possibly be used for making large-scale ecosystem comparisons. The various methods and approaches are illustrated with examples drawn from the literature.

  15. Low temperature alteration processes affecting ultramafic bodies

    USGS Publications Warehouse

    Nesbitt, H.W.; Bricker, O.P.

    1978-01-01

    At low temperatures, in the presence of an aqueous solution, olivine and orthopyroxene are not stable relative to the hydrous phases brucite, serpentine and talc. Alteration of dunite and peridotite to serpentine or steatite bodies must therefore proceed via non-equilibrium processes. The compositions of natural solutions emanating from dunites and peridotites demonstrate that the dissolution of forsterite and/or enstatite is rapid compared with the precipitation of the hydrous phases; consequently, dissolution of anhydrous minerals controls the chemistry of such solutions. In the presence of an aqueous phase, precipitation of hydrous minerals is the rate-controlling step. Brucite-bearing and -deficient serpentinites alter at low temperature by non-equilibrium processes, as evidenced by the composition of natural solutions from these bodies. The solutions approach equilibrium with the least stable hydrous phase and, as a consequence, are supersaturated with other hydrous phases. Dissolution of the least stable phase is rapid compared to precipitation of other phases, so that the dissolving mineral controls the solution chemistry. Non-equilibrium alteration of anhydrous ultramafic bodies continues until at least one anhydrous phase equilibrates with brucite, chrysotile or talc. The lowest temperature (at a given pressure) at which this happens is defined by the reaction: 3H2O + 2Mg2SiO4 ??? Mg3Si2O5(OH)4 + Mg(OH)2 (Johannes, 1968, Contrib. Mineral. Petrol. 19, 309-315) so that non-equilibrium alteration may occur well into greenschist facies metamorphic conditions. ?? 1978.

  16. How does wind-throw disturbance affect the carbon budget of an upland spruce forest ecosystem?

    NASA Astrophysics Data System (ADS)

    Lindauer, Matthias; Schmid, Hans Peter; Grote, Rüdiger; Mauder, Matthias; Wolpert, Benjamin; Steinbrecher, Rainer

    2014-05-01

    Forests, especially in mid-latitudes are generally designated as large carbon sinks. However, stand-replacing disturbance events like fires, insect-infestations, or severe wind-storms can shift an ecosystem from carbon sink to carbon source within short time and keep it as this for a long time. In Addition, extreme weather situations which promote the occurrence of ecosystem disturbances are likely to increase in the future due to climate change. The development and competition of different vegetation types (spruce vs. grass) as well as soil organic matter (SOM), and their contribution to the net ecosystem exchange (NEE), in such disturbed forest ecosystems are largely unknown. In a large wind-throw area (ca. 600 m diameter, due to cyclone Kyrill in January 2007) within a mature upland spruce forest, where dead-wood has not been removed, in the Bavarian Forest National Park (Lackenberg, 1308 m a.s.l., Bavaria, Germany), fluxes of CO2, water vapor and energy have been measured with the Eddy Covariance (EC) method since 2009. Model simulations (MoBiLE) were used to estimate the GPP components from trees and grassland as well as to differentiate between soil and plant respiration, and to get an idea about the long term behavior of the ecosystems carbon exchange. For 2009, 2010, 2011, 2012, and 2013 estimates of annual Net Ecosystem Exchange (NEE) showed that the wind-throw was a marked carbon source. However, the few remaining trees and newly emerging vegetation (grass, sparse young spruce, etc.) lead to an already strong Gross Ecosystem Production (GEP). Model simulations conformed well with the measurements. To our knowledge, we present the worldwide first long-term measurements of NEE within a non-cleared wind-throw-disturbed forest ecosystem.

  17. Comparing soil biogeochemical processes in novel and natural boreal forest ecosystems

    NASA Astrophysics Data System (ADS)

    Quideau, S. A.; Swallow, M. J. B.; Prescott, C. E.; Grayston, S. J.; Oh, S.-W.

    2013-04-01

    Emulating the variability that exists in the natural landscape prior to disturbance should be a goal of soil reconstruction and land reclamation efforts following resource extraction. Long-term ecosystem sustainability within reclaimed landscapes can only be achieved with the re-establishment of biogeochemical processes between reconstructed soils and plants. In this study, we assessed key soil biogeochemical attributes (nutrient availability, organic matter composition, and microbial communities) in reconstructed, novel, anthropogenic ecosystems covering different reclamation treatments following open-cast mining for oil extraction. We compared the attributes to those present in a range of natural soils representative of mature boreal forest ecosystems in the same area of northern Alberta. Soil nutrient availability was determined in situ with resin probes, organic matter composition was described with 13C nuclear magnetic resonance spectroscopy and soil microbial community structure was characterized using phospholipid fatty acid analysis. Significant differences among natural ecosystems were apparent in nutrient availability and seemed more related to the dominant tree cover than to soil type. When analyzed together, all natural forests differed significantly from the novel ecosystems, in particular with respect to soil organic matter composition. However, there was some overlap between the reconstructed soils and some of the natural ecosystems in nutrient availability and microbial communities, but not in organic matter characteristics. Hence, our results illustrate the importance of considering the range of natural landscape variability, and including several soil biogeochemical attributes when comparing novel, anthropogenic ecosystems to the mature ecosystems that constitute ecological targets.

  18. Comparing soil biogeochemical processes in novel and natural boreal forest ecosystems

    NASA Astrophysics Data System (ADS)

    Quideau, S. A.; Swallow, M. J. B.; Prescott, C. E.; Grayston, S. J.; Oh, S.-W.

    2013-08-01

    Emulating the variability that exists in the natural landscape prior to disturbance should be a goal of soil reconstruction and land reclamation efforts following resource extraction. Long-term ecosystem sustainability within reclaimed landscapes can only be achieved with the re-establishment of biogeochemical processes between reconstructed soils and plants. In this study, we assessed key soil biogeochemical attributes (nutrient availability, organic matter composition, and microbial communities) in reconstructed, novel, anthropogenic ecosystems, covering different reclamation treatments following open-cast mining for oil extraction. We compared the attributes to those present in a range of natural soils representative of mature boreal forest ecosystems in the same area of Northern Alberta. Soil nutrient availability was determined in situ with resin probes, organic matter composition was described with 13C nuclear magnetic resonance spectroscopy and soil microbial community structure was characterized using phospholipid fatty acid analysis. Significant differences among natural ecosystems were apparent in nutrient availability and seemed more related to the dominant tree cover than to soil type. When analyzed together, all natural forests differed significantly from the novel ecosystems, in particular with respect to soil organic matter composition. However, there was some overlap between the reconstructed soils and some of the natural ecosystems in nutrient availability and microbial communities, but not in organic matter characteristics. Hence, our results illustrate the importance of considering the range of natural landscape variability and including several soil biogeochemical attributes when comparing novel, anthropogenic ecosystems to the mature ecosystems that constitute ecological targets.

  19. Cloud Processed CCN Affect Cloud Microphysics

    NASA Astrophysics Data System (ADS)

    Hudson, J. G.; Noble, S. R., Jr.; Tabor, S. S.

    2015-12-01

    Variations in the bimodality/monomodality of CCN spectra (Hudson et al. 2015) exert opposite effects on cloud microphysics in two aircraft field projects. The figure shows two examples, droplet concentration, Nc, and drizzle liquid water content, Ld, against classification of CCN spectral modality. Low ratings go to balanced separated bimodal spectra, high ratings go to single mode spectra, strictly monomodal 8. Intermediate ratings go merged modes, e.g., one mode a shoulder of another. Bimodality is caused by mass or hygroscopicity increases that go only to CCN that made activated cloud droplets. In the Ice in Clouds Experiment-Tropical (ICE-T) small cumuli with lower Nc, greater droplet mean diameters, MD, effective radii, re, spectral widths, σ, cloud liquid water contents, Lc, and Ld were closer to more bimodal (lower modal ratings) below cloud CCN spectra whereas clouds with higher Nc, smaller MD, re, σ, and Ld were closer to more monomodal CCN (higher modal ratings). In polluted stratus clouds of the MArine Stratus/Stratocumulus Experiment (MASE) clouds that had greater Nc, and smaller MD, re, σ, Lc, and Ld were closer to more bimodal CCN spectra whereas clouds with lower Nc, and greater MD, re, σ, Lc, and Ld were closer to more monomodal CCN. These relationships are opposite because the dominant ICE-T cloud processing was coalescence whereas chemical transformations (e.g., SO2 to SO4) were dominant in MASE. Coalescence reduces Nc and thus also CCN concentrations (NCCN) when droplets evaporate. In subsequent clouds the reduced competition increases MD and σ, which further enhance coalescence and drizzle. Chemical transformations do not change Nc but added sulfate enhances droplet and CCN solubility. Thus, lower critical supersaturation (S) CCN can produce more cloud droplets in subsequent cloud cycles, especially for the low W and effective S of stratus. The increased competition reduces MD, re, and σ, which inhibit coalescence and thus reduce drizzle

  20. Studies of dynamical processes affecting global climate

    SciTech Connect

    Keller, C.; Cooper, D.; Eichinger, W.

    1998-12-31

    This is the final report of a three-year, Laboratory Directed Research and Development project at the Los Alamos National Laboratory (LANL). The main objective was, by a combined theoretical and observational approach, to develop improved models of dynamic processes in the oceans and atmosphere and to incorporate them into large climate codes, chiefly in four main areas: numerical physics, chemistry, water vapor, and ocean-atmosphere interactions. Main areas of investigation included studies of: cloud parameterizations for global climate codes, Lidar and the planetary boundary layer, chemistry, climate variability using coupled ocean-atmospheric models, and numerical physical methods. This project employed a unique approach that included participation of a number of University of California faculty, postdoctoral fellows and graduate students who collaborated with Los Alamos research staff on specific tasks, thus greatly enhancing the research output. Overall accomplishments during the sensing of the atmospheric planetary were: (1) first two- and three-dimensional remote sensing of the atmospheric planetary boundary layer using Lidars, (2) modeling of 20-year cycle in both pressure and sea surface temperatures in North Pacific, (3) modeling of low frequency internal variability, (4) addition of aerosols to stratosphere to simulate Pinatubo effect on ozone, (5) development of fast, comprehensive chemistry in the troposphere for urban pollution studies, (6) new prognostic cloud parameterization in global atmospheric code remedied problems with North Pacific atmospheric circulation and excessive equatorial precipitation, (7) development of a unique aerosol analysis technique, the aerosol time-of-flight mass spectrometer (ATOFMS), which allows real-time analysis of the size and chemical composition of individual aerosol particles, and (8) numerical physics applying Approximate Inertial Manifolds to ocean circulation. 14 refs., 6 figs.

  1. Factors Affecting Trophic Control of Community Structure and Ecosystem Functioning in Experimental Mesocosms of Seagrass (Zostera marina L.)

    NASA Astrophysics Data System (ADS)

    Lefcheck, J.; Duffy, J.

    2008-12-01

    Nutrient loading of coastal and estuarine waters threatens seagrass communities by promoting the growth of micro- and macroalgae, which then reduce the availability of light and nutrients. However, populations of invertebrate mesograzers are able to mitigate the negative impact of eutrophication through top-down control. We performed a factorial mesocosm experiment to examine the interactive relationships between light, nutrients, and mesograzer presence in structuring experimental ecosystems of eelgrass (Zostera marina). We found that mesograzer presence strongly reduced epiphytic algal biomass in every case, which remains consistent with previous mesocosm studies. We also observed a synergistic light-by-nutrient interaction that enhanced both epiphyte biomass and mesograzer abundance. The timing of this relationship is suggestive of weaker bottom-up control. Unlike previous studies, we found that light alone rarely affected either epiphyte biomass or mesograzer abundance. We believe that this result may be due to a combination of macroalgal shading and persistent grazing. Further processing of primary and secondary producer biomasses and elemental ratios, as well as the completion of feeding assays to gauge mesograzer feeding rates on different types of algae, will serve to reinforce these conclusions and to better define the relationship between these factors.

  2. Implicit affectivity and rapid processing of affective body language: An fMRI study.

    PubMed

    Suslow, Thomas; Ihme, Klas; Quirin, Markus; Lichev, Vladimir; Rosenberg, Nicole; Bauer, Jochen; Bomberg, Luise; Kersting, Anette; Hoffmann, Karl-Titus; Lobsien, Donald

    2015-10-01

    Previous research has revealed affect-congruity effects for the recognition of affects from faces. Little is known about the impact of affect on the perception of body language. The aim of the present study was to investigate the relationship of implicit (versus explicit) affectivity with the recognition of briefly presented affective body expressions. Implicit affectivity, which can be measured using indirect assessment methods, has been found to be more predictive of spontaneous physiological reactions than explicit (self-reported) affect. Thirty-four healthy women had to label the expression of body postures (angry, fearful, happy, or neutral) presented for 66 ms and masked by a neutral body posture in a forced-choice format while undergoing functional magnetic resonance imaging (fMRI). Participants' implicit affectivity was assessed using the Implicit Positive and Negative Affect Test. Measures of explicit state and trait affectivity were also administered. Analysis of the fMRI data was focused on a subcortical network involved in the rapid perception of affective body expressions. Only implicit negative affect (but not explicit affect) was correlated with correct labeling performance for angry body posture. As expected, implicit negative affect was positively associated with activation of the subcortical network in response to fearful and angry expression (compared to neutral expression). Responses of the caudate nucleus to affective body expression were especially associated with its recognition. It appears that processes of rapid recognition of affects from body postures could be facilitated by an individual's implicit negative affect. PMID:26032148

  3. Elaboration Likelihood and the Counseling Process: The Role of Affect.

    ERIC Educational Resources Information Center

    Stoltenberg, Cal D.; And Others

    The role of affect in counseling has been examined from several orientations. The depth of processing model views the efficiency of information processing as a function of the extent to which the information is processed. The notion of cognitive processing capacity states that processing information at deeper levels engages more of one's limited…

  4. Characterizing Zinc Speciation in Soils from a Smelter-Affected Boreal Forest Ecosystem.

    PubMed

    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. PMID:27065416

  5. An elevational gradient in snowpack chemical loading at Glacier National Park, Montana: implications for ecosystem processes

    USGS Publications Warehouse

    Fagre, Daniel; Tonnessen, Kathy; Morris, Kristi; Ingersoll, George; McKeon, Lisa; Holzer, Karen

    2000-01-01

    The accumulation and melting of mountain snowpacks are major drivers of ecosystem processes in the Rocky Mountains. These include the influence of snow water equivalent (SWE) timing and amount of release on soil moisture for annual tree growth, and alpine stream discharge and temperature that control aquatic biota life histories. Snowfall also brings with it atmospheric deposition. Snowpacks will hold as much as 8 months of atmospheric deposition for release into mountain ecosystems during the spring melt. These pulses of chemicals influence soil microbiota and biogeochemical processes affecting mountain vegetation growth. Increased atmospheric nitrogen inputs recently have been documented in remote parts of Colorado's mountain systems but no baseline data exist for the Northern Rockies. We examined patterns of SWE and snow chemistry in an elevational gradient stretching from west to east over the continental divide in Glacier National Park in March 1999 and 2000. Sites ranged from 1080m to 2192m at Swiftcurrent Pass. At each site, two vertically-integrated columns of snow were sampled from snowpits up to 600cm deep and analyzed for major cations and anions. Minor differences in snow chemistry, on a volumetric basis, existed over the elvational gradient. Snowpack chemical loading estimates were calculated for NH4, SO4 and NO3 and closely followed elevational increases in SWE. NO3 (in microequivalents/square meter) ranged from 1,000 ueq/m2 at low elevation sites to 8,000+ ueq/m2 for high elevation sites. Western slopes received greater amounts of SWE and chemical loads for all tested compounds.

  6. Evaluating assumptions and parameterization underlying process-based ecosystem models: the case of LPJ-GUESS

    NASA Astrophysics Data System (ADS)

    Pappas, C.; Fatichi, S.; Leuzinger, S.; Burlando, P.

    2012-04-01

    Dynamic vegetation models have been widely used for analyzing ecosystem dynamics and climate feedbacks. Their performance has been tested extensively against observations and by model intercomparison studies. In the present study, the LPJ-GUESS state-of-the-art ecosystem model was evaluated with respect to its structure, hypothesis, and parameterization by performing a global sensitivity analysis (GSA). The study aims at examining potential model limitations, particularly with regards to regional and watershed scale applications. A detailed GSA based on variance decomposition is presented to investigate the structural assumptions of the model and to highlight processes and parameters that cause the highest variability in the outputs. First order and total sensitivity indexes were calculated for each of the parameters using Sobol's methodology. In order to elucidate the role of climate on model sensitivity synthetic climate scenarios were generated based on climatic data from Switzerland. The results clearly indicate a very high sensitivity of LPJ-GUESS to photosynthetic parameters. Intrinsic quantum efficiency alone is able to explain about 60% of the variability in vegetation carbon fluxes and pools for most of the investigated climate conditions. Processes related to light were also found important together with parameters affecting plant structure (growth, establishment and mortality). The model shows minor sensitivity to hydrological and soil texture parameters, questioning its skills in representing spatial vegetation heterogeneity at regional or watershed scales. We conclude that LPJ-GUESS' structure and possibly the one of other, structurally similar, dynamic vegetation models may need to be reconsidered. Specifically, the oversensitivity of the photosynthetic component deserves a particular attention, as this seems to contradict an increasing number of observations suggesting that photosynthesis may be a consequence rather than the driver of plant growth.

  7. The Ecohydrological Consequences of Woody Plant Encroachment: How Accessibility to Deep Soil Water Resources Affects Ecosystem Carbon and Water Exchange

    NASA Astrophysics Data System (ADS)

    Scott, R. L.; Huxman, T. E.; Barron-Gafford, G.; Jenerette, D.; Young, J. M.

    2013-12-01

    Woody plant encroachment into grassland systems, a process that has increased rapidly over the last century, has potentially broad ecohydrological consequences by affecting the way ecosystems use water and cycle carbon. This study examines the influence of precipitation- and groundwater-derived water availability by comparing eddy covariance measurements of water vapor and carbon dioxide fluxes over a riparian grassland, shrubland, and woodland, and an upland grassland site in southeastern Arizona USA. Compared to the upland grassland, the riparian sites exhibited greater net carbon uptake (NEP) and higher evapotranspiration (ET) across a longer portion of the year. Among the riparian sites, however, the grassland was less able to take advantage of the stable groundwater supply. Increasing woody plant density facilitated greater water and carbon exchange that became increasingly decoupled from incident precipitation (P). How groundwater accessibility affected NEP was more complex than ET. Respiration (Reco) costs were higher for the riparian grassland so, while it had a similar ET and gross carbon uptake (GEP) to the shrubland, its NEP was substantially less. Also, riparian grassland fluxes were much more variable due to flooding that occurred at the site, which could stimulate or inhibit NEP. Woodland NEP was largest but surprisingly similar to the less mature and dense shrubland even while having much greater GEP. Woodland NEP responded negatively to P, due to the stimulation of Reco likely due to greater amounts of aboveground and soil carbon. With many areas of the world experiencing woody plants encroachment, encroachment into areas where there are additional deep soil water sources, such as in riparian settings or in areas of deep soil moisture recharge, will likely increase carbon sequestration but at the expense of higher water use.

  8. Ecological Processes of Isolated Wetlands: Ecosystem Services and the Significant Nexus (Invited)

    NASA Astrophysics Data System (ADS)

    Lengler, U.; De Lucia, M.; Kuehn, M.

    2011-12-01

    Geographically isolated wetlands occur throughout the US and are characterized by a wetland system completely surrounded by uplands. Examples include prairie potholes, woodland seasonal (i.e., vernal) pools, cypress domes, playas, and other such systems. Decisions by the US Supreme Court in 2001 and 2006 have affected the jurisdictional status of geographically isolated wetlands such that those failing to have a demonstrable 'significant nexus' to navigable waters may have no federal protection under the Clean Water Act. These systems are typically small and, as such, may be under-counted in assessments of area and abundance. Areal extent is a portion of the information required to characterize the functions associated with geographically isolated wetlands and understanding both site-specific and larger-scale processes are also required to better quantify those functions. In addition, quantifying anthropogenic effects on system processing informs our understanding of the contributions and the connectivity of geographically isolated wetlands to other waters. This presentation focuses on both efforts to quantify the contribution of geographically isolated wetlands to system-scale processes, focusing on nutrient assimilation and hydrologic storage, as well as concurrent research to identify their locations at multiple scales. Findings from this research may help elucidate the link between geographically isolated wetlands and other systems, and may inform discussions on ecosystem services provided by geographically isolated wetlands.

  9. Ecological Processes of Isolated Wetlands: Ecosystem Services and the Significant Nexus (Invited)

    NASA Astrophysics Data System (ADS)

    Lane, C.; Autrey, B.; D'Amico, E.

    2013-12-01

    Geographically isolated wetlands occur throughout the US and are characterized by a wetland system completely surrounded by uplands. Examples include prairie potholes, woodland seasonal (i.e., vernal) pools, cypress domes, playas, and other such systems. Decisions by the US Supreme Court in 2001 and 2006 have affected the jurisdictional status of geographically isolated wetlands such that those failing to have a demonstrable 'significant nexus' to navigable waters may have no federal protection under the Clean Water Act. These systems are typically small and, as such, may be under-counted in assessments of area and abundance. Areal extent is a portion of the information required to characterize the functions associated with geographically isolated wetlands and understanding both site-specific and larger-scale processes are also required to better quantify those functions. In addition, quantifying anthropogenic effects on system processing informs our understanding of the contributions and the connectivity of geographically isolated wetlands to other waters. This presentation focuses on both efforts to quantify the contribution of geographically isolated wetlands to system-scale processes, focusing on nutrient assimilation and hydrologic storage, as well as concurrent research to identify their locations at multiple scales. Findings from this research may help elucidate the link between geographically isolated wetlands and other systems, and may inform discussions on ecosystem services provided by geographically isolated wetlands.

  10. Ecosystem processes and nitrogen export in northern U.S. watersheds.

    USGS Publications Warehouse

    Stottlemyer, R.

    2001-01-01

    There is much interest in the relationship of atmospheric nitrogen (N) inputs to ecosystem outputs as an indicator of possible "nitrogen saturation" by human activity. Longer-term, ecosystem-level mass balance studies suggest that the relationship is not clear and that other ecosystem processes may dominate variation in N outputs. We have been studying small, forested watershed ecosystems in five northern watersheds for periods up to 35 years. Here I summarize the research on ecosystem processes and the N budget. During the past 2 decades, average wet-precipitation N inputs ranged from about 0.1 to 6 kg N ha(-1) year(-1) among sites. In general, sites with the lowest N inputs had the highest output-to-input ratios. In the Alaska watersheds, streamwater N output exceeded inputs by 70 to 250%. The ratio of mean monthly headwater nitrate (NO3-) concentration to precipitation NO3- concentration declined with increased precipitation concentration. A series of ecosystem processes have been studied and related to N outputs. The most important appear to be seasonal change in hydrologic flowpath, soil freezing, seasonal forest-floor inorganic N pools resulting from over-winter mineralization beneath the snowpack, spatial variation in watershed forest-floor inorganic N pools, the degree to which snowmelt percolates soils, and gross soil N mineralization rates.

  11. How a clogged canal affects ecological and human health in a tropical urban wetland ecosystem

    EPA Science Inventory

    The coastal city of San Juan, Puerto Rico is a tropical urban ecosystem woven among a series of interconnected bays, lagoons, drains, canals, and mangroves. As the city has expanded, infilling and urban development by the region’s poorest residents has choked an important c...

  12. International conference on physiological process studies in the Arctic: (Implications for ecosystems response to climate change)

    SciTech Connect

    Chapin, F.S. II.

    1991-01-01

    The conference on physiological process studies in the Arctic was held in Toronto, Canada, to summarize the current understanding of plant physiological processes in the Arctic. Participants reviewed the current understanding of arctic ecophysiology and discussed the role of physiology in controlling ecosystem processes such as productivity and nutrient cycling. Emphasis was placed on ways in which ecophysiological studies might provide insight into possible responses of arctic ecosystems to global climatic change. The major conclusions of the workshop were that, although we know a great deal about the adaptations of arctic plants to their physical environment, the biotic interactions among plants and between plants and other organisms are more important in governing the distribution of plants in the Arctic. Future research in arctic physiological ecology should emphasize biotic interactions, feedbacks and time lags that modify plant response to environment, and the roles that plants play as regulators of ecosystem processes.

  13. Inferring Group Processes from Computer-Mediated Affective Text Analysis

    SciTech Connect

    Schryver, Jack C; Begoli, Edmon; Jose, Ajith; Griffin, Christopher

    2011-02-01

    Political communications in the form of unstructured text convey rich connotative meaning that can reveal underlying group social processes. Previous research has focused on sentiment analysis at the document level, but we extend this analysis to sub-document levels through a detailed analysis of affective relationships between entities extracted from a document. Instead of pure sentiment analysis, which is just positive or negative, we explore nuances of affective meaning in 22 affect categories. Our affect propagation algorithm automatically calculates and displays extracted affective relationships among entities in graphical form in our prototype (TEAMSTER), starting with seed lists of affect terms. Several useful metrics are defined to infer underlying group processes by aggregating affective relationships discovered in a text. Our approach has been validated with annotated documents from the MPQA corpus, achieving a performance gain of 74% over comparable random guessers.

  14. Emotion-specific load disrupts concomitant affective processing.

    PubMed

    Vermeulen, Nicolas; Niedenthal, Paula M; Pleyers, Gordy; Bayot, Marie; Corneille, Olivier

    2014-01-01

    Findings in the neuroimaging literature suggest that separate brain circuitries are involved when individuals perform emotional compared to nonemotional working memory (WM) tasks. Here we test this hypothesis with behavioural measures. We predicted that the conceptual processing of affect would be disrupted more by concurrent affective than nonaffective load. Participants performed a conceptual task in which they verified affective versus sensory properties of concepts, and a second, concurrent, working memory (n-back) task in which the target stimuli were facial expressions. Results revealed that storing and updating affective (as compared with identity) features of facial expressions altered performance more for affective than for sensory properties of concepts. The findings are supportive of the ideas that affective resources exist and that these resources are specifically used during the processing and representation of affective properties of objects and events.

  15. A trait-based framework for predicting when and where microbial adaptation to climate change will affect ecosystem functioning

    USGS Publications Warehouse

    Wallenstein, Matthew D.; Hall, Edward K.

    2012-01-01

    As the earth system changes in response to human activities, a critical objective is to predict how biogeochemical process rates (e.g. nitrification, decomposition) and ecosystem function (e.g. net ecosystem productivity) will change under future conditions. A particular challenge is that the microbial communities that drive many of these processes are capable of adapting to environmental change in ways that alter ecosystem functioning. Despite evidence that microbes can adapt to temperature, precipitation regimes, and redox fluctuations, microbial communities are typically not optimally adapted to their local environment. For example, temperature optima for growth and enzyme activity are often greater than in situ temperatures in their environment. Here we discuss fundamental constraints on microbial adaptation and suggest specific environments where microbial adaptation to climate change (or lack thereof) is most likely to alter ecosystem functioning. Our framework is based on two principal assumptions. First, there are fundamental ecological trade-offs in microbial community traits that occur across environmental gradients (in time and space). These trade-offs result in shifting of microbial function (e.g. ability to take up resources at low temperature) in response to adaptation of another trait (e.g. limiting maintenance respiration at high temperature). Second, the mechanism and level of microbial community adaptation to changing environmental parameters is a function of the potential rate of change in community composition relative to the rate of environmental change. Together, this framework provides a basis for developing testable predictions about how the rate and degree of microbial adaptation to climate change will alter biogeochemical processes in aquatic and terrestrial ecosystems across the planet.

  16. Implicit Processing of Visual Emotions Is Affected by Sound-Induced Affective States and Individual Affective Traits

    PubMed Central

    Quarto, Tiziana; Blasi, Giuseppe; Pallesen, Karen Johanne; Bertolino, Alessandro; Brattico, Elvira

    2014-01-01

    The ability to recognize emotions contained in facial expressions are affected by both affective traits and states and varies widely between individuals. While affective traits are stable in time, affective states can be regulated more rapidly by environmental stimuli, such as music, that indirectly modulate the brain state. Here, we tested whether a relaxing or irritating sound environment affects implicit processing of facial expressions. Moreover, we investigated whether and how individual traits of anxiety and emotional control interact with this process. 32 healthy subjects performed an implicit emotion processing task (presented to subjects as a gender discrimination task) while the sound environment was defined either by a) a therapeutic music sequence (MusiCure), b) a noise sequence or c) silence. Individual changes in mood were sampled before and after the task by a computerized questionnaire. Additionally, emotional control and trait anxiety were assessed in a separate session by paper and pencil questionnaires. Results showed a better mood after the MusiCure condition compared with the other experimental conditions and faster responses to happy faces during MusiCure compared with angry faces during Noise. Moreover, individuals with higher trait anxiety were faster in performing the implicit emotion processing task during MusiCure compared with Silence. These findings suggest that sound-induced affective states are associated with differential responses to angry and happy emotional faces at an implicit stage of processing, and that a relaxing sound environment facilitates the implicit emotional processing in anxious individuals. PMID:25072162

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

    PubMed

    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.

  18. The Humboldt Current System: Ecosystem components and processes, fisheries, and sediment studies

    NASA Astrophysics Data System (ADS)

    Montecino, Vivian; Lange, Carina B.

    2009-12-01

    In the Humboldt Current System (HCS), biological and non-biological components, ecosystem processes, and fisheries are known to be affected by multi-decadal, inter-annual, annual, and intra-seasonal scales. The interplay between atmospheric variability, the poleward undercurrent, the shallow oxygen minimum zone (OMZ), and the fertilizing effect of coastal upwelling and overall high primary production rates drive bio-physical interactions, the carbon biomass, and fluxes of gases and particulate and dissolved matter through the water column. Coastal upwelling (permanent and seasonally modulated off Peru and northern Chile, and markedly seasonal between 30°S and 40°S) is the key process responsible for the high biological productivity in the HCS. At present, the western coast of South America produces more fish per unit area than any other region in the world ocean (i.e. ∼7.5 × 10 6 t of anchoveta were landed in 2007). Climate changes on different temporal scales lead to alterations in the distribution ranges of anchoveta and sardine populations and shifts in their dominance throughout the HCS. The factors affecting the coastal marine ecosystem that reverberate in the fisheries are crucial from a social perspective, since the economic consequences of mismanagement can be severe. Fish remains are often well-preserved in sediment settings under the hypoxic conditions of the OMZ off Peru and Chile, and reveal multi-decadal variability and centennial-scale changes in fish populations. Sediment studies from the Chilean continental margin encompassing the last 20,000 years of deposition reveal changes in sub-surface conditions in the HCS during deglaciation, interpreted to include: a major reorganization of the OMZ; a deglacial increase in denitrification decoupled from local marine productivity; and higher deglacial and Holocene paleoproductivities compared to the Last Glacial Maximum in central-south Chile (35-37°S) while this scheme is reversed for north

  19. Fine sediment as environmental stressor affecting freshwater mussel behavior and ecosystem services.

    PubMed

    Lummer, Eva-Maria; Auerswald, Karl; Geist, Juergen

    2016-11-15

    Fine sediment pollution is considered a major stressor for aquatic ecosystems and their biodiversity. In particular, fine sediments have been suggested to play a crucial role in the declines of freshwater mussels which are considered keystone fauna of streams and rivers. Whereas the effects of deposited fine sediments on recruitment failure are well known, effects of suspended fine sediments on adult mussel behavior are less studied. Therefore the aim of this study was to investigate the effects of fine sediment exposure on freshwater mussel behavior and on mussel-dependent ecosystem services. Unio pictorum mussels were used to test three behavioral endpoints: Hall activity, transition frequency and relative water clearance rate. Mussels were exposed to fine sediments of different particle size classes (<45μm, 45-63μm, 63-125μm) and different concentration (0-10gL(-1)) of the smallest particle size class. Hall sensor technology and turbidity measurements were used to detect mussel behavior in presence of suspended sediments. Results revealed that mussels improve clearance of suspended particles out of the water column by 35%, independent of particle size class and concentration. Transition frequency was determined an unsuitable behavioral endpoint for non-soluble substances. Contrary to previous studies, we could demonstrate that fine sediments do not interfere with filtration by mussels and that mussels have a great influence on water purification, providing a valuable ecosystem service. PMID:27422724

  20. Unmasking the effect of a precipitation pulse on the biological processes composing Net Ecosystem Carbon Exchange

    NASA Astrophysics Data System (ADS)

    Lopez-Ballesteros, Ana; Sanchez-Cañete, Enrique P.; Serrano-Ortiz, Penelope; Oyonarte, Cecilio; Kowalski, Andrew S.; Perez-Priego, Oscar; Domingo, Francisco

    2015-04-01

    Drylands occupy 47.2% of the global terrestrial area and are key ecosystems that significantly determine the inter-annual variability of the global carbon balance. However, it is still necessary to delve into the functional behavior of arid and semiarid ecosystems due to the complexity of drivers and interactions between underpinning processes (whether biological or abiotic) that modulate net ecosystem CO2 exchange (NEE). In this context, water inputs are crucial to biological organisms survival in arid ecosystems and frequently arrive via rain events that are commonly stochastic and unpredictable (i.e. precipitation pulses) and strongly control arid land ecosystem structure and function. The eddy covariance technique can be used to investigate the effect of precipitation pulses on NEE, but provide limited understanding of what exactly happens after a rain event. The chief reasons are that, firstly, we cannot measure separately autotrophic and heterotrophic components, and secondly, the partitioning techniques widely utilized to separate Gross Primary Production and Total Ecosystem Respiration, do not work properly in these water-limited ecosystems, resulting in biased estimations of plant and soil processes. Consequently, it is essential to combine eddy covariance measurements with other techniques to disentangle the different biological processes composing NEE that are activated by a precipitation pulse. Accordingly, the main objectives of this work were: (i) to quantify the contribution of precipitation pulse events to annual NEE using the eddy covariance technique in a semiarid steppe located in Almería (Spain), and (ii) to simulate a realistic precipitation pulse in order to understand its effect on the ecosystem, soil and plant CO2 exchanges by using a transitory-state closed canopy chamber, soil respiration chambers and continuous monitoring CO2 sensors inserted in the subsoil. Preliminary results showed, as expected, a delay between soil and plant

  1. Positive and negative affective processing exhibit dissociable functional hubs during the viewing of affective pictures.

    PubMed

    Zhang, Wenhai; Li, Hong; Pan, Xiaohong

    2015-02-01

    Recent resting-state functional magnetic resonance imaging (fMRI) studies using graph theory metrics have revealed that the functional network of the human brain possesses small-world characteristics and comprises several functional hub regions. However, it is unclear how the affective functional network is organized in the brain during the processing of affective information. In this study, the fMRI data were collected from 25 healthy college students as they viewed a total of 81 positive, neutral, and negative pictures. The results indicated that affective functional networks exhibit weaker small-worldness properties with higher local efficiency, implying that local connections increase during viewing affective pictures. Moreover, positive and negative emotional processing exhibit dissociable functional hubs, emerging mainly in task-positive regions. These functional hubs, which are the centers of information processing, have nodal betweenness centrality values that are at least 1.5 times larger than the average betweenness centrality of the network. Positive affect scores correlated with the betweenness values of the right orbital frontal cortex (OFC) and the right putamen in the positive emotional network; negative affect scores correlated with the betweenness values of the left OFC and the left amygdala in the negative emotional network. The local efficiencies in the left superior and inferior parietal lobe correlated with subsequent arousal ratings of positive and negative pictures, respectively. These observations provide important evidence for the organizational principles of the human brain functional connectome during the processing of affective information.

  2. The "Point Zero": Monitoring of biogeochemical patterns and processes in an initial ecosystem (Lusatia, Germany)

    NASA Astrophysics Data System (ADS)

    Veste, M.; Biemelt, D.; Fischer, A.; Gerwin, W.; Schaaf, W.

    2009-04-01

    Ecosystems are highly complex systems composed of many different abiotic and biotic compartments that are closely linked by interacting processes and co-develop over long-term periods. Most integrating studies have been carried out in 'climax' ecosystems and only limited knowledge exists about the initial phase of ecosystem development although it is hypothesized that the conditions at ´point zeró and the processes of the initial phase determine and control further development. ‘Point zero' of the ecosystem development was analysed at e.g. volcanic regions of Hawaii, Mount St. Helens and Iceland and also in glacier retreat areas in the Arctic, Antarctic and the Alps. The attempt to study patterns and processes of initial ecosystem development at an artificial catchment is a novel approach to disentangle the complex interactions and feedback mechanisms typically found in mature ecosystems and to understand the relevance and importance of initial conditions on further development and future state of an ecosystem. The watershed approach allows to integrate the relevant processes with related pattern and structure development over temporal and spatial scales and to derive thresholds and stages in state and functioning at the catchment level. To allow the clear definition of as homogeneous as possible starting conditions at ´point zeró and to be able to integrate spatially distributed processes and patterns to larger units, an artificial catchment was constructed in the mining area of Lusatia, Germany. This artificial catchment ´Hühnerwasseŕ with an area of about 6 ha was constructed as a 2-4 m layer of post-glacial sandy to loamy sediments overlying a 1-2 m layer of Tertiary clay that forms a shallow pan and seals the whole catchment at the base. A comprehensive monitoring program is carried out in the catchment including: meteorology, atmospheric bulk deposition, dust deposition, grid soil sampling, soil solution chemistry (ions, DOC, TOC, grain size, etc

  3. Is the Climate of Bering Sea Warming and Affecting the Ecosystem?

    NASA Astrophysics Data System (ADS)

    Overland, James E.; Stabeno, Phyllis J.

    2004-08-01

    Observations from the Bering Sea are good indicators of decadal shifts in climate, as the Bering is a transition region between the cold, dry Arctic air mass to the north, and the moist, relatively warm maritime air mass to the south. The Bering Sea is also a transition region between Arctic and sub-Arctic ecosystems; this boundary can be loosely identified with the extent of winter sea-ice cover. Like a similar transition zone in the eastern North Atlantic, the Bering Sea is experiencing a northward biogeographical shift in response to changing temperature and atmospheric forcing. If this shift continues over the next decade, it will have major impacts on commercial and subsistence harvests as Arctic species are displaced by sub-Arctic species. The stakes are enormous, as this rich and diverse ecosystem currently provides 47% of the U.S. fishery production by weight, and is home to 80% of the U.S. sea bird population, 95% of northern fur seals, and major populations of Steller sea lions, walrus, and whales.

  4. Programmer's Guide for FFORM. Physical Processes in Terrestrial and Aquatic Ecosystems, Computer Programs and Graphics Capabilities.

    ERIC Educational Resources Information Center

    Anderson, Lougenia; Gales, Larry

    This module is part of a series 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. FFORM is a portable format-free input subroutine package written in ANSI Fortran IV…

  5. Foundations of Physical Theory, I: Force and Energy. Physical Processes in Terrestrial and Aquatic Ecosystems, Fundamentals.

    ERIC Educational Resources Information Center

    Pearson, Nolan E.

    This module is part of a series 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 module is one of two units on the foundations of physical theory and the…

  6. Calculus - Differentiation. Physical Processes in Terrestrial and Aquatic Ecosystems, Applied Mathematics.

    ERIC Educational Resources Information Center

    Hertzberg, Richard C.

    This module is part of a series 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 module is used to introduce the biology student to differential calculus, a…

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

    ERIC Educational Resources Information Center

    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…

  8. TRANSLOCATION OF NUTRIENTS BY FRESHWATER MUSSELS – ALTERATION OF ECOSYSTEM AND COMMUNITY PROCESSES

    EPA Science Inventory

    Nutrient demand and availability is a major driver of ecosystem processes. We examined the impact of freshwater mussels, a highly imperiled faunal group, on nitrogen (N) and phosphorus (P) cycling and storage in three Oklahoma streams. We found that filter-feeding by freshwater m...

  9. Modelling hydrological processes and analysing water-related ecosystem services of Western Siberian lowland basins

    NASA Astrophysics Data System (ADS)

    Schmalz, Britta; Kiesel, Jens; Kruse, Marion; Pfannerstill, Matthias; Sheludkov, Artyom; Khoroshavin, Vitaliy; Veshkurseva, Tatyana; Müller, Felix; Fohrer, Nicola

    2015-04-01

    For discussing and planning sustainable land management of river basins, stakeholders need suitable information on spatio-temporal patterns of hydrological components and ecosystem services. The ecosystem services concept, i.e., services provided by ecosystems that contribute to human welfare benefits, contributes comprehensive information for sustainable river management. This study shows an approach to use ecohydrological modelling results for quantifying and assessing water-related ecosystem services in three lowland river basins in Western Siberia, a region which is of global significance in terms of carbon sequestration, agricultural production and biodiversity preservation. Using the ecohydrological model SWAT, the three basins Pyschma (16762 km²), Vagai (3348 km²) and Loktinka (373 km²) were modelled following a gradient from the landscape units taiga, pre-taiga to forest steppe. For a correct representation of the Siberian lowland hydrology, the consideration of snow melt and retention of surface runoff as well as the implementation of a second groundwater aquifer was of great importance. Good to satisfying model performances were obtained for the extreme hydrological conditions. The simulated SWAT output variables of different hydrological processes were used as indicators for the two regulating services water flow and erosion regulation. The model results were translated into a relative ecosystem service valuation scale. The resulting ecosystem service maps show different spatial and seasonal patterns. Although the high resolution modelling results are averaged out within the aggregated relative valuation scale, seasonal differences can be depicted: during snowmelt, low relevant regulation can be determined, especially for water flow regulation, but a very high relevant regulation was calculated for the vegetation period during summer and for the winter period. The SWAT model serves as a suitable quantification method for the assessment of water

  10. Animal Thermoregulation and the Operative Environmental (Equivalent) Temperature. Physical Processes in Terrestrial and Aquatic Ecosystems, Transport Process.

    ERIC Educational Resources Information Center

    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. Thermoregulation is defined as the ability of an organism to modify its body temperature. This…

  11. Heat Balance of a Sheep in the Sun. Physical Processes in Terrestrial and Aquatic Ecosystems, Transport Processes.

    ERIC Educational Resources Information Center

    Hatheway, W. H.

    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. Specifically, this module develops a method for calculating the exchange of heat between an…

  12. Visualizing microbial dechlorination processes in underground ecosystem by statistical correlation and network analysis approach.

    PubMed

    Yamazawa, Akira; Date, Yasuhiro; Ito, Keijiro; Kikuchi, Jun

    2014-03-01

    Microbial ecosystems are typified by diverse microbial interactions and competition. Consequently, the microbial networks and metabolic dynamics of bioprocesses catalyzed by these ecosystems are highly complex, and their visualization is regarded as essential to bioengineering technology and innovation. Here we describe a means of visualizing the variants in a microbial community and their metabolic profiles. The approach enables previously unidentified bacterial functions in the ecosystems to be elucidated. We investigated the anaerobic bioremediation of chlorinated ethene in a soil column experiment as a case study. Microbial community and dechlorination profiles in the ecosystem were evaluated by denaturing gradient gel electrophoresis (DGGE) fingerprinting and gas chromatography, respectively. Dechlorination profiles were obtained from changes in dechlorination by microbial community (evaluated by data mining methods). Individual microbes were then associated with their dechlorination profiles by heterogenous correlation analysis. Our correlation-based visualization approach enables deduction of the roles and functions of bacteria in the dechlorination of chlorinated ethenes. Because it estimates functions and relationships between unidentified microbes and metabolites in microbial ecosystems, this approach is proposed as a control-logic tool by which to understand complex microbial processes. PMID:24095212

  13. Climatic Versus Biotic Constraints on Carbon and Water Fluxes in Seasonally Drought-affected Ponderosa Pine Ecosystems. Chapter 2

    NASA Technical Reports Server (NTRS)

    Schwarz, P. A.; Law, B. E.; Williams, M.; Irvine, J.; Kurpius, M.; Moore, D.

    2005-01-01

    We investigated the relative importance of climatic versus biotic controls on gross primary production (GPP) and water vapor fluxes in seasonally drought-affected ponderosa pine forests. The study was conducted in young (YS), mature (MS), and old stands (OS) over 4 years at the AmeriFlux Metolius sites. Model simulations showed that interannual variation of GPP did not follow the same trends as precipitation, and effects of climatic variation were smallest at the OS (50%), and intermediate at the YS (<20%). In the young, developing stand, interannual variation in leaf area has larger effects on fluxes than climate, although leaf area is a function of climate in that climate can interact with age-related shifts in carbon allocation and affect whole-tree hydraulic conductance. Older forests, with well-established root systems, appear to be better buffered from effects of seasonal drought and interannual climatic variation. Interannual variation of net ecosystem exchange (NEE) was also lowest at the OS, where NEE is controlled more by interannual variation of ecosystem respiration, 70% of which is from soil, than by the variation of GPP, whereas variation in GPP is the primary reason for interannual changes in NEE at the YS and MS. Across spatially heterogeneous landscapes with high frequency of younger stands resulting from natural and anthropogenic disturbances, interannual climatic variation and change in leaf area are likely to result in large interannual variation in GPP and NEE.

  14. Progressive nitrogen limitation of ecosystem processes under elevated CO2 in a warm-temperate forest.

    PubMed

    Finzi, Adrien C; Moore, David J P; DeLucia, Evan H; Lichter, John; Hofmockel, Kirsten S; Jackson, Robert B; Kim, Hyun-Seok; Matamala, Roser; McCarthy, Heather R; Oren, Ram; Pippen, Jeffrey S; Schlesinger, William H

    2006-01-01

    A hypothesis for progressive nitrogen limitation (PNL) proposes that net primary production (NPP) will decline through time in ecosystems subjected to a step-function increase in atmospheric CO2. The primary mechanism driving this response is a rapid rate of N immobilization by plants and microbes under elevated CO2 that depletes soils of N, causing slower rates of N mineralization. Under this hypothesis, there is little long-term stimulation of NPP by elevated CO2 in the absence of exogenous inputs of N. We tested this hypothesis using data on the pools and fluxes of C and N in tree biomass, microbes, and soils from 1997 through 2002 collected at the Duke Forest free-air CO2 enrichment (FACE) experiment. Elevated CO2 stimulated NPP by 18-24% during the first six years of this experiment. Consistent with the hypothesis for PNL, significantly more N was immobilized in tree biomass and in the O horizon under elevated CO2. In contrast to the PNL hypothesis, microbial-N immobilization did not increase under elevated CO2, and although the rate of net N mineralization declined through time, the decline was not significantly more rapid under elevated CO2. Ecosystem C-to-N ratios widened more rapidly under elevated CO2 than ambient CO2 indicating a more rapid rate of C fixation per unit of N, a processes that could delay PNL in this ecosystem. Mass balance calculations demonstrated a large accrual of ecosystem N capital. Is PNL occurring in this ecosystem and will NPP decline to levels under ambient CO2? The answer depends on the relative strength of tree biomass and O-horizon N immobilization vs. widening C-to-N ratios and ecosystem-N accrual as processes that drive and delay PNL, respectively. Only direct observations through time will definitively answer this question.

  15. Developing a participatory process to include ecosystem services in landscape planing

    NASA Astrophysics Data System (ADS)

    Onaindia, Miren; Palacios-Agundez, Igone; Rodríguez-Loinaz, Gloria; Peña, Lorena; Madariaga, Iosu; Ametzaga, Ibone

    2015-04-01

    This work develops an approach that integrates scientific knowledge on ecosystem services and stakeholders demands to get guidelines for landscape planning strategies in the region of Biscay (Basque Country, northern Spain). In the conducted participatory process, forest multi-functionality was considered as a practicable good alternative. This process identified also a knowledge gap on the synergies and trade-offs between biodiversity, timber production and carbon storage, guiding the directions of the research actions. The results from developed spatial analysis converged with those from the participatory process in the adequacy of promoting, where possible and appropriate, natural forest ecosystems restoration. The ongoing stepwise learning strategy is already showing its effectiveness for decision making, with concrete examples of how the results obtained with the applied approach are being included in planning and decision-making processes.

  16. Water ecosystem service function assessment based on eco-hydrological process in Luanhe Basin,China

    NASA Astrophysics Data System (ADS)

    Zhang, C.; Hao, C.; Qin, T.; Wang, G.; Weng, B.

    2012-12-01

    At present, ecological water are mainly occupied by a rapid development of social economic and population explosion, which seriously threat the ecological security and water security in watershed and regional scale. Due to the lack of a unified standard of measuring the benefit of water resource, social economic and ecosystem, the water allocation can't take place in social economic and ecosystem. The function which provided by water in terrestrial, aquatic and social economic system can be addressed through water ecosystem service function research, and it can guide the water allocation in water resource management. The function which provided by water in terrestrial, aquatic and social economic system can be addressed through water ecosystem service function research, and it can guide the water allocation in water resource management. Throughout the researches of water ecosystem service, a clear identification of the connection of water ecosystem service function has not been established, and eco-economic approach can't meet the practical requirement of water allocation. Based on "nature-artificiality" dual water cycle theory and eco-hydrological process, this paper proposes a connection and indicator system of water ecosystem service function. In approach, this paper establishes an integrated assessment approach through prototype observation technology, numerical simulation, physical simulation and modern geographic information technology. The core content is to couple an eco-hydrological model, which involves the key processes of distributed hydrological model (WEP), ecological model (CLM-DGVM), in terms of eco-hydrological process. This paper systematically evaluates the eco-hydrological process and evolution of Luanhe Basin in terms of precipitation, ET, runoff, groundwater, ecosystem's scale, form and distribution. According to the results of eco-hydrological process, this paper assesses the direct and derived service function. The result indicates that the

  17. Relationship between auditory processing and affective prosody in schizophrenia.

    PubMed

    Jahshan, Carol; Wynn, Jonathan K; Green, Michael F

    2013-02-01

    Patients with schizophrenia have well-established deficits in their ability to identify emotion from facial expression and tone of voice. In the visual modality, there is strong evidence that basic processing deficits contribute to impaired facial affect recognition in schizophrenia. However, few studies have examined the auditory modality for mechanisms underlying affective prosody identification. In this study, we explored links between different stages of auditory processing, using event-related potentials (ERPs), and affective prosody detection in schizophrenia. Thirty-six schizophrenia patients and 18 healthy control subjects received tasks of affective prosody, facial emotion identification, and tone matching, as well as two auditory oddball paradigms, one passive for mismatch negativity (MMN) and one active for P300. Patients had significantly reduced MMN and P300 amplitudes, impaired auditory and visual emotion recognition, and poorer tone matching performance, relative to healthy controls. Correlations between ERP and behavioral measures within the patient group revealed significant associations between affective prosody recognition and both MMN and P300 amplitudes. These relationships were modality specific, as MMN and P300 did not correlate with facial emotion recognition. The two ERP waves accounted for 49% of the variance in affective prosody in a regression analysis. Our results support previous suggestions of a relationship between basic auditory processing abnormalities and affective prosody dysfunction in schizophrenia, and indicate that both relatively automatic pre-attentive processes (MMN) and later attention-dependent processes (P300) are involved with accurate auditory emotion identification. These findings provide support for bottom-up (e.g., perceptually based) cognitive remediation approaches.

  18. In the dark: A review of ecosystem processes during the Arctic polar night

    NASA Astrophysics Data System (ADS)

    Berge, Jørgen; Renaud, Paul E.; Darnis, Gerald; Cottier, Finlo; Last, Kim; Gabrielsen, Tove M.; Johnsen, Geir; Seuthe, Lena; Weslawski, Jan Marcin; Leu, Eva; Moline, Mark; Nahrgang, Jasmine; Søreide, Janne E.; Varpe, Øystein; Lønne, Ole Jørgen; Daase, Malin; Falk-Petersen, Stig

    2015-12-01

    Several recent lines of evidence indicate that the polar night is key to understanding Arctic marine ecosystems. First, the polar night is not a period void of biological activity even though primary production is close to zero, but is rather characterized by a number of processes and interactions yet to be fully understood, including unanticipated high levels of feeding and reproduction in a wide range of taxa and habitats. Second, as more knowledge emerges, it is evident that a coupled physical and biological perspective of the ecosystem will redefine seasonality beyond the "calendar perspective". Third, it appears that many organisms may exhibit endogenous rhythms that trigger fitness-maximizing activities in the absence of light-based cues. Indeed a common adaptation appears to be the ability to utilize the dark season for reproduction. This and other processes are most likely adaptations to current environmental conditions and community and trophic structures of the ecosystem, and may have implications for how Arctic ecosystems can change under continued climatic warming.

  19. Bioaccumulation of mercury in benthic communities of a river ecosystem affected by mercury mining.

    PubMed

    Zizek, Suzana; Horvat, Milena; Gibicar, Darija; Fajon, Vesna; Toman, Mihael J

    2007-05-15

    The presence of mercury in the river Idrijca (Slovenia) is mainly due to 500 years of mercury mining in this region. In order to understand the cycling of mercury in the Idrijca ecosystem it is crucial to investigate the role of biota. This study is part of an ongoing investigation of mercury biogeochemistry in the river Idrijca, focusing on the accumulation and speciation of mercury in the lower levels of the food chain, namely filamentous algae, periphyton and macroinvertebrates. Mercury analysis and speciation in the biota and in water were performed during the spring, summer and autumn seasons at four locations on the river, representing different degrees of mercury contamination. Total (THg) and methyl mercury (MeHg) were measured. The results showed that the highest THg concentrations in biota correlate well with THg levels in sediments and water. The level of MeHg is spatially and seasonally variable, showing higher values at the most contaminated sites during the summer and autumn periods. The percentage of Hg as MeHg increases with the trophic level from water (0.1-0.8%), algae (0.5-1.3%), periphyton (1.6-8.8%) to macroinvertebrates (0.1-100%), which indicates active transformation, accumulation and magnification of mercury in the benthic organism of this heavily contaminated torrential river.

  20. Phenology, Ecosystem Processes, and Climate Change: What We Are Learning from the Phenocam Network

    NASA Astrophysics Data System (ADS)

    Richardson, A. D.

    2014-12-01

    Phenology has been shown to be a robust integrator of the effects of year-to-year climate variability and longer-term climate change on natural systems. At the level of organisms, phenology plays a critical role in processes related to growth, reproduction, and competition. At the level of ecosystems, phenology is important because of implications for productivity, carbon sequestration, nutrient cycling, and feedbacks to the climate system. At decadal-to-century time scales, climate change will indirectly cause additional shifts in ecosystem phenology via shifts in community composition and structure. There is a demonstrated need to better document biological responses to a changing world, and improved phenological monitoring will contribute to achieving this goal. In this talk, I will describe a collaborative research network called "PhenoCam" (http://phenocam.sr.unh.edu/). PhenoCam uses networked digital cameras - webcams - for phenological monitoring in a range of ecosystems (over 100 sites, and 300+ site-years of archived data) across the North American continent. These sites range from coastal wetlands of the southeast to mountain highlands of the northwest, and from the hot deserts of Arizona to the cold of arctic Alaska. Images are captured every 30 minutes, are uploaded to the PhenoCam server for display in real-time, and are then processed to yield measures of vegetation greenness. I will discuss how we are using data from PhenoCam (1) to improve understanding of the environmental controls on phenology at organism-to-ecosystem scales; (2) to relate ecosystem processes (e.g. carbon and water fluxes measured via eddy covariance) to phenology; and (3) to develop predictive models and forecast future climate change impacts on phenology.

  1. Non-linear interactions determine the impact of sea-level rise on estuarine benthic biodiversity and ecosystem processes.

    PubMed

    Yamanaka, Tsuyuko; Raffaelli, David; White, Piran C L

    2013-01-01

    Sea-level rise induced by climate change may have significant impacts on the ecosystem functions and ecosystem services provided by intertidal sediment ecosystems. Accelerated sea-level rise is expected to lead to steeper beach slopes, coarser particle sizes and increased wave exposure, with consequent impacts on intertidal ecosystems. We examined the relationships between abundance, biomass, and community metabolism of benthic fauna with beach slope, particle size and exposure, using samples across a range of conditions from three different locations in the UK, to determine the significance of sediment particle size beach slope and wave exposure in affecting benthic fauna and ecosystem function in different ecological contexts. Our results show that abundance, biomass and oxygen consumption of intertidal macrofauna and meiofauna are affected significantly by interactions among sediment particle size, beach slope and wave exposure. For macrofauna on less sloping beaches, the effect of these physical constraints is mediated by the local context, although for meiofauna and for macrofauna on intermediate and steeper beaches, the effects of physical constraints dominate. Steeper beach slopes, coarser particle sizes and increased wave exposure generally result in decreases in abundance, biomass and oxygen consumption, but these relationships are complex and non-linear. Sea-level rise is likely to lead to changes in ecosystem structure with generally negative impacts on ecosystem functions and ecosystem services. However, the impacts of sea-level rise will also be affected by local ecological context, especially for less sloping beaches. PMID:23861863

  2. Non-Linear Interactions Determine the Impact of Sea-Level Rise on Estuarine Benthic Biodiversity and Ecosystem Processes

    PubMed Central

    Yamanaka, Tsuyuko; Raffaelli, David; White, Piran C. L.

    2013-01-01

    Sea-level rise induced by climate change may have significant impacts on the ecosystem functions and ecosystem services provided by intertidal sediment ecosystems. Accelerated sea-level rise is expected to lead to steeper beach slopes, coarser particle sizes and increased wave exposure, with consequent impacts on intertidal ecosystems. We examined the relationships between abundance, biomass, and community metabolism of benthic fauna with beach slope, particle size and exposure, using samples across a range of conditions from three different locations in the UK, to determine the significance of sediment particle size beach slope and wave exposure in affecting benthic fauna and ecosystem function in different ecological contexts. Our results show that abundance, biomass and oxygen consumption of intertidal macrofauna and meiofauna are affected significantly by interactions among sediment particle size, beach slope and wave exposure. For macrofauna on less sloping beaches, the effect of these physical constraints is mediated by the local context, although for meiofauna and for macrofauna on intermediate and steeper beaches, the effects of physical constraints dominate. Steeper beach slopes, coarser particle sizes and increased wave exposure generally result in decreases in abundance, biomass and oxygen consumption, but these relationships are complex and non-linear. Sea-level rise is likely to lead to changes in ecosystem structure with generally negative impacts on ecosystem functions and ecosystem services. However, the impacts of sea-level rise will also be affected by local ecological context, especially for less sloping beaches. PMID:23861863

  3. Non-linear interactions determine the impact of sea-level rise on estuarine benthic biodiversity and ecosystem processes.

    PubMed

    Yamanaka, Tsuyuko; Raffaelli, David; White, Piran C L

    2013-01-01

    Sea-level rise induced by climate change may have significant impacts on the ecosystem functions and ecosystem services provided by intertidal sediment ecosystems. Accelerated sea-level rise is expected to lead to steeper beach slopes, coarser particle sizes and increased wave exposure, with consequent impacts on intertidal ecosystems. We examined the relationships between abundance, biomass, and community metabolism of benthic fauna with beach slope, particle size and exposure, using samples across a range of conditions from three different locations in the UK, to determine the significance of sediment particle size beach slope and wave exposure in affecting benthic fauna and ecosystem function in different ecological contexts. Our results show that abundance, biomass and oxygen consumption of intertidal macrofauna and meiofauna are affected significantly by interactions among sediment particle size, beach slope and wave exposure. For macrofauna on less sloping beaches, the effect of these physical constraints is mediated by the local context, although for meiofauna and for macrofauna on intermediate and steeper beaches, the effects of physical constraints dominate. Steeper beach slopes, coarser particle sizes and increased wave exposure generally result in decreases in abundance, biomass and oxygen consumption, but these relationships are complex and non-linear. Sea-level rise is likely to lead to changes in ecosystem structure with generally negative impacts on ecosystem functions and ecosystem services. However, the impacts of sea-level rise will also be affected by local ecological context, especially for less sloping beaches.

  4. Higher biodiversity is required to sustain multiple ecosystem processes across temperature regimes.

    PubMed

    Perkins, Daniel M; Bailey, R A; Dossena, Matteo; Gamfeldt, Lars; Reiss, Julia; Trimmer, Mark; Woodward, Guy

    2015-01-01

    Biodiversity loss is occurring rapidly worldwide, yet it is uncertain whether few or many species are required to sustain ecosystem functioning in the face of environmental change. The importance of biodiversity might be enhanced when multiple ecosystem processes (termed multifunctionality) and environmental contexts are considered, yet no studies have quantified this explicitly to date. We measured five key processes and their combined multifunctionality at three temperatures (5, 10 and 15 °C) in freshwater aquaria containing different animal assemblages (1-4 benthic macroinvertebrate species). For single processes, biodiversity effects were weak and were best predicted by additive-based models, i.e. polyculture performances represented the sum of their monoculture parts. There were, however, significant effects of biodiversity on multifunctionality at the low and the high (but not the intermediate) temperature. Variation in the contribution of species to processes across temperatures meant that greater biodiversity was required to sustain multifunctionality across different temperatures than was the case for single processes. This suggests that previous studies might have underestimated the importance of biodiversity in sustaining ecosystem functioning in a changing environment.

  5. Higher biodiversity is required to sustain multiple ecosystem processes across temperature regimes

    PubMed Central

    Perkins, Daniel M; Bailey, R A; Dossena, Matteo; Gamfeldt, Lars; Reiss, Julia; Trimmer, Mark; Woodward, Guy

    2015-01-01

    Biodiversity loss is occurring rapidly worldwide, yet it is uncertain whether few or many species are required to sustain ecosystem functioning in the face of environmental change. The importance of biodiversity might be enhanced when multiple ecosystem processes (termed multifunctionality) and environmental contexts are considered, yet no studies have quantified this explicitly to date. We measured five key processes and their combined multifunctionality at three temperatures (5, 10 and 15 °C) in freshwater aquaria containing different animal assemblages (1–4 benthic macroinvertebrate species). For single processes, biodiversity effects were weak and were best predicted by additive-based models, i.e. polyculture performances represented the sum of their monoculture parts. There were, however, significant effects of biodiversity on multifunctionality at the low and the high (but not the intermediate) temperature. Variation in the contribution of species to processes across temperatures meant that greater biodiversity was required to sustain multifunctionality across different temperatures than was the case for single processes. This suggests that previous studies might have underestimated the importance of biodiversity in sustaining ecosystem functioning in a changing environment. PMID:25131335

  6. Extreme events and the terrestrial carbon cycle - mechanisms, processes and impacts on different ecosystem types-

    NASA Astrophysics Data System (ADS)

    Frank, Dorothea; Reichstein, Markus

    2013-04-01

    Severe droughts, heat waves, extreme precipitation or storms can impact the structure, composition, and functioning of terrestrial ecosystems and thus their carbon cycling and carbon sequestration potential. Besides direct impacts on the carbon fluxes of photosynthesis and respiration, extreme events may also trigger further partially lagged phenomena such as heat wave and drought related fires, pest and pathogen outbreaks following heavy storm caused windthrow or drought stress reduced plant health. Extreme events have the potential to cause rapid carbon losses from accumulated stocks, as well as long-lasting impacts on the carbon cycle due to direct and lagged effects on plant growth and mortality, going often beyond the duration of the extreme event itself. Extreme events have the potential to impact the terrestrial ecosystem carbon balance through a single factor or as a combination of factors, and forests, grassland and croplands are differently affected by the various types of extremes.

  7. Climate change and Southern Ocean ecosystems I: how changes in physical habitats directly affect marine biota.

    PubMed

    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.

  8. Developing Worksheet Based on Science Process Skills: Factors Affecting Solubility

    ERIC Educational Resources Information Center

    Karsli, Fethiye; Sahin, Cigdem

    2009-01-01

    The purpose of this study is to develop a worksheet about the factors affecting solubility, which could be useful for the prospective science teachers (PST) to remind and regain their science process skills (SPS). The pilot study of the WS was carried out with 32 first grade PST during the 2007-2008 academic year in the education department at…

  9. Feedbacks between structures and processes during initial ecosystem development in an artificial catchment

    NASA Astrophysics Data System (ADS)

    Schaaf, Wolfgang; Elemer, Michael; Gerwin, Werner; Fischer, Anton; Zaplata, Markus; Neneov, Rossen

    2013-04-01

    We studied the role of strutures and processes and their feedbacks during initial ecosystem development in the artificial catchment Chicken Creek. During the first seven years, considerable changes within the catchment were observed. Both internal and external factors could be identified as driving forces for the formation of structures and patterns in the artificial catchment. Initial structures formed by the construction process and initial substrate characteristics were decisive for the distribution and flow of water. External factors like episodic events triggered erosion and dissection during this initial phase, promoted by the low vegetation cover and the unconsolidated sandy substrate. The transformation of the initial geo-system into areas with evolving terrestrial or aquatic characteristics and from a very episodic to a more permanent stream network and discharge, together with the observed vegetation dynamics increased site diversity and heterogeneity with respect to water and nutrient availability and transformation processes compared to the more homogenous conditions at point zero. The processes and feedback mechanisms in the initial development of a new landscape may deviate in rates, intensity and dominance from those known from mature ecosystems. It is therefore crucial to understand these early phases of ecosystem development and to disentangle the increasingly complex interactions between the evolving terrestrial and aquatic, biotic and abiotic compartments of the system. Artificially created catchments could be a suitable tool to study these initial developments at the landscape scale under known, designed and defined boundary conditions.

  10. Regional processes in mangrove ecosystems: Spatial scaling relationships, biomass, and turnover rates following catastrophic disturbance

    USGS Publications Warehouse

    Ward, G.A.; Smith, T. J.; Whelan, K.R.T.; Doyle, T.W.

    2006-01-01

    Physiological processes and local-scale structural dynamics of mangroves are relatively well studied. Regional-scale processes, however, are not as well understood. Here we provide long-term data on trends in structure and forest turnover at a large scale, following hurricane damage in mangrove ecosystems of South Florida, U.S.A. Twelve mangrove vegetation plots were monitored at periodic intervals, between October 1992 and March 2005. Mangrove forests of this region are defined by a -1.5 scaling relationship between mean stem diameter and stem density, mirroring self-thinning theory for mono-specific stands. This relationship is reflected in tree size frequency scaling exponents which, through time, have exhibited trends toward a community average that is indicative of full spatial resource utilization. These trends, together with an asymptotic standing biomass accumulation, indicate that coastal mangrove ecosystems do adhere to size-structured organizing principles as described for upland tree communities. Regenerative dynamics are different between areas inside and outside of the primary wind-path of Hurricane Andrew which occurred in 1992. Forest dynamic turnover rates, however, are steady through time. This suggests that ecological, more-so than structural factors, control forest productivity. In agreement, the relative mean rate of biomass growth exhibits an inverse relationship with the seasonal range of porewater salinities. The ecosystem average in forest scaling relationships may provide a useful investigative tool of mangrove community biomass relationships, as well as offer a robust indicator of general ecosystem health for use in mangrove forest ecosystem management and restoration. ?? Springer 2006.

  11. Comparison of seasonal soil microbial process in snow-covered temperate ecosystems of northern China.

    PubMed

    Zhang, Xinyue; Wang, Wei; Chen, Weile; Zhang, Naili; Zeng, Hui

    2014-01-01

    More than half of the earth's terrestrial surface currently experiences seasonal snow cover and soil frost. Winter compositional and functional investigations in soil microbial community are frequently conducted in alpine tundra and boreal forest ecosystems. However, little information on winter microbial biogeochemistry is known from seasonally snow-covered temperate ecosystems. As decomposer microbes may differ in their ability/strategy to efficiently use soil organic carbon (SOC) within different phases of the year, understanding seasonal microbial process will increase our knowledge of biogeochemical cycling from the aspect of decomposition rates and corresponding nutrient dynamics. In this study, we measured soil microbial biomass, community composition and potential SOC mineralization rates in winter and summer, from six temperate ecosystems in northern China. Our results showed a clear pattern of increased microbial biomass C to nitrogen (N) ratio in most winter soils. Concurrently, a shift in soil microbial community composition occurred with higher fungal to bacterial biomass ratio and gram negative (G-) to gram positive (G+) bacterial biomass ratio in winter than in summer. Furthermore, potential SOC mineralization rate was higher in winter than in summer. Our study demonstrated a distinct transition of microbial community structure and function from winter to summer in temperate snow-covered ecosystems. Microbial N immobilization in winter may not be the major contributor for plant growth in the following spring.

  12. Managed island ecosystems

    USGS Publications Warehouse

    McEachern, Kathryn; Atwater, Tanya; Collins, Paul W.; Faulkner, Kate R.; Richards, Daniel V.

    2016-01-01

    This long-anticipated reference and sourcebook for California’s remarkable ecological abundance provides an integrated assessment of each major ecosystem type—its distribution, structure, function, and management. A comprehensive synthesis of our knowledge about this biologically diverse state, Ecosystems of California covers the state from oceans to mountaintops using multiple lenses: past and present, flora and fauna, aquatic and terrestrial, natural and managed. Each chapter evaluates natural processes for a specific ecosystem, describes drivers of change, and discusses how that ecosystem may be altered in the future. This book also explores the drivers of California’s ecological patterns and the history of the state’s various ecosystems, outlining how the challenges of climate change and invasive species and opportunities for regulation and stewardship could potentially affect the state’s ecosystems. The text explicitly incorporates both human impacts and conservation and restoration efforts and shows how ecosystems support human well-being. Edited by two esteemed ecosystem ecologists and with overviews by leading experts on each ecosystem, this definitive work will be indispensable for natural resource management and conservation professionals as well as for undergraduate or graduate students of California’s environment and curious naturalists.

  13. Investigating facial affect processing in psychosis: a study using the Comprehensive Affective Testing System.

    PubMed

    Rossell, Susan L; Van Rheenen, Tamsyn E; Joshua, Nicole R; O'Regan, Alison; Gogos, Andrea

    2014-08-01

    Facial affect processing (FAP) deficits in schizophrenia (SZ) and bipolar disorder (BD) have been widely reported; although effect sizes vary across studies, and there are limited direct comparisons of the two groups. Further, there is debate as to the influence of both psychotic and mood symptoms on FAP. This study aimed to address these limitations by recruiting groups of psychosis patients with either a diagnosis of SZ or BD and comparing them to healthy controls (HC) on a well validated battery of four FAP subtests: affect discrimination, name affect, select affect and match affect. Overall, both groups performed more poorly than controls in terms of accuracy. In SZ, this was largely driven by impairments on three of the four subtests. The BD patients showed impaired performance specifically on the match affect subtest, a task that had a high cognitive load. FAP performance in the psychosis patients was correlated with severity of positive symptoms and mania. This study confirmed that FAP deficits are a consistent finding in SZ that occur independent of task specific methodology; whilst FAP deficits in BD are more subtle. Further work in this group is needed to replicate these results.

  14. From neurons to epidemics: How trophic coherence affects spreading processes

    NASA Astrophysics Data System (ADS)

    Klaise, Janis; Johnson, Samuel

    2016-06-01

    Trophic coherence, a measure of the extent to which the nodes of a directed network are organised in levels, has recently been shown to be closely related to many structural and dynamical aspects of complex systems, including graph eigenspectra, the prevalence or absence of feedback cycles, and linear stability. Furthermore, non-trivial trophic structures have been observed in networks of neurons, species, genes, metabolites, cellular signalling, concatenated words, P2P users, and world trade. Here, we consider two simple yet apparently quite different dynamical models—one a susceptible-infected-susceptible epidemic model adapted to include complex contagion and the other an Amari-Hopfield neural network—and show that in both cases the related spreading processes are modulated in similar ways by the trophic coherence of the underlying networks. To do this, we propose a network assembly model which can generate structures with tunable trophic coherence, limiting in either perfectly stratified networks or random graphs. We find that trophic coherence can exert a qualitative change in spreading behaviour, determining whether a pulse of activity will percolate through the entire network or remain confined to a subset of nodes, and whether such activity will quickly die out or endure indefinitely. These results could be important for our understanding of phenomena such as epidemics, rumours, shocks to ecosystems, neuronal avalanches, and many other spreading processes.

  15. From neurons to epidemics: How trophic coherence affects spreading processes.

    PubMed

    Klaise, Janis; Johnson, Samuel

    2016-06-01

    Trophic coherence, a measure of the extent to which the nodes of a directed network are organised in levels, has recently been shown to be closely related to many structural and dynamical aspects of complex systems, including graph eigenspectra, the prevalence or absence of feedback cycles, and linear stability. Furthermore, non-trivial trophic structures have been observed in networks of neurons, species, genes, metabolites, cellular signalling, concatenated words, P2P users, and world trade. Here, we consider two simple yet apparently quite different dynamical models-one a susceptible-infected-susceptible epidemic model adapted to include complex contagion and the other an Amari-Hopfield neural network-and show that in both cases the related spreading processes are modulated in similar ways by the trophic coherence of the underlying networks. To do this, we propose a network assembly model which can generate structures with tunable trophic coherence, limiting in either perfectly stratified networks or random graphs. We find that trophic coherence can exert a qualitative change in spreading behaviour, determining whether a pulse of activity will percolate through the entire network or remain confined to a subset of nodes, and whether such activity will quickly die out or endure indefinitely. These results could be important for our understanding of phenomena such as epidemics, rumours, shocks to ecosystems, neuronal avalanches, and many other spreading processes. PMID:27368799

  16. Bark Beetle Impacts on Ecosystem Processes are Over Quickly and Muted Spatially

    NASA Astrophysics Data System (ADS)

    Ewers, B. E.; Norton, U.; Borkhuu, B.; Reed, D. E.; Peckham, S. D.; Biederman, J. A.; King, A.; Gochis, D. J.; Brooks, P. D.; Harpold, A. A.; Frank, J. M.; Massman, W. J.; Mackay, D. S.; Pendall, E. G.

    2013-12-01

    The recent epidemic of bark beetles across western North America has impacted conifers from low to high elevations from New Mexico to Yukon. The mechanism of mortality is clear, with both mountain pine and spruce beetles killing trees by introducing xylem occluding blue stain fungi which dramatically stops transpiration. The visual impact of this outbreak is stunning, with mortality of canopy trees over 90% in some stands. However, emerging work shows that the impact on ecosystem processes is not as dramatic. We hypothesize that increased soil water and nitrogen sets up rapid succession of plant communities, which quickly restores ecosystem processing of water, carbon and nitrogen, while spatial patchiness of mortality and belowground responses mutes the impact as spatial scale increases from stands to watersheds. In support of our hypothesis we found 1) Soil nitrogen and moisture increase within one growing season but decrease to the same as uninfested stands five years later. 2) Soil respiration is correlated with live tree basal area suggesting a large component of autotrophic respiration. 3) Once stands have more than 50% basal area mortality, seedling density increases up to five fold and total non-tree understory cover increased two fold both within five years after infestation. 4) Ecosystem scale estimates of water vapor fluxes do not decline as rapidly as overstory leaf area. 5) Stable isotopes of snow, soil and stream water suggest that increased below canopy evapotranspiration nearly compensates for reduced canopy transpiration. 6) Nested watershed data shows that precipitation variations are much more important in regulating streamflow than changes in canopies from bark beetle induced mortality. These results were tested in the Terrestrial Regional Ecosystem Exchange Simulator (TREES) model. TREES was able to predict annual changes in the carbon fluxes but had difficulty simulating soil moisture and annual water budgets likely due to inadequate abiotic

  17. Native shrub reestablishment in exotic annual grasslands: do ecosystem processes recover?

    PubMed

    Yelenik, S G; Levine, J M

    2010-04-01

    The impacts of exotic plant species on ecosystem processes are well established, motivating numerous efforts to facilitate native-species recovery. Nonetheless, how the return of native species influences ecosystem processes and how these changes feed back to influence the recovery process are poorly understood. We examined these questions in exotic annual grasslands on Santa Cruz Island, California, USA, where the removal of nonnative herbivores has led to the recovery of the native shrubs Artemisia californica and Eriogonum arborescens. To examine the influence of shrub colonization on nutrient cycling, and the mechanisms by which these changes arise, we measured available nitrogen and phosphorus, and quantified nitrogen mineralization and litterfall rates under shrubs and grasses in the field and in experimental monoculture plots. Both native shrubs altered nitrogen cycling as they colonized the grassland, but they did so in opposite directions. Eriogonum depressed nitrogen pools and mineralization rates via large inputs of nitrogen-poor litter. In contrast Artemisia increased nitrogen and phosphorus pools and nitrogen mineralization rates. Last, to determine if shrub effects on soils favor shrubs or grasses, we conducted a nitrogen and phosphorus fertilization experiment in the field. Only the exotic grass was significantly limited by nitrogen. Thus the depressed nitrogen availability associated with Eriogonum colonization is more harmful to exotic grasses than to the native shrub. By contrast, the elevated nitrogen associated with recovering Artemisia favors grasses over the shrub, possibly hindering recovery of the native. Mechanistic studies of the ecosystem ,impacts of native-plant recovery are useful for managers wishing to predict which native species return ecosystem function, and whether such changes feed back to influence native recovery. PMID:20437958

  18. Belowground processes regulate ecosystem nitrogen retention during a multi-year forest dieback event

    NASA Astrophysics Data System (ADS)

    Nave, L. E.; Le Moine, J.; Gough, C. M.; Vogel, C.; Nadelhoffer, K. J.; Curtis, P.

    2013-12-01

    In the absence of disturbances, forests typically have strong retention capacity for nitrogen (N), which is internally recycled between soil, microbial and plant pools. However, disturbances that trigger senescence or mortality of forest vegetation may alter internal N cycling processes and lead to the loss of ecosystem N retention capacity. Here, we present an assessment of the role played by belowground processes in governing ecosystem N cycling and retention during an experimental disturbance that killed the dominant canopy taxa in a Great Lakes forest over a 4-year period. After applying stem girdling to hasten the age-related senescence of the dominant taxa (Populus and Betula spp.; ~35% of the basal area), we observed a 38% decrease in stand-level allocation of nonstructural carbohydrates to fine roots, which triggered a tenfold increase in the rate of fine root turnover and increased soil NH4+ and NO3- availability. Elevated soil N availability decreased mycorrhizal hyphal foraging and N uptake, effectively down-regulating the role of symbiotic fungi in the N nutrition of the residual (longer-lived) tree taxa. However, even as residual trees took up less N from mycorrhizal sources, their overall N uptake increased and served to offset the loss of the dominant taxa. The net result of this offset was that canopy N stocks remained constant through the disturbance period and there was no appreciable loss of ecosystem N stocks due to leaching or gaseous export. In sum, the cascade of changes in root, microbial, and soil processes during this experiment indicates that these interdependent components of the belowground system comprised a mechanism responsible for retention and redistribution of ecosystem N stocks during the disturbance period.

  19. Electrophysiological differences in the processing of affect misattribution.

    PubMed

    Hashimoto, Yohei; Minami, Tetsuto; Nakauchi, Shigeki

    2012-01-01

    The affect misattribution procedure (AMP) was proposed as a technique to measure an implicit attitude to a prime image [1]. In the AMP, neutral symbols (e.g., a Chinese pictograph, called the target) are presented, following an emotional stimulus (known as the prime). Participants often misattribute the positive or negative affect of the priming images to the targets in spite of receiving an instruction to ignore the primes. The AMP effect has been investigated using behavioral measures; however, it is difficult to identify when the AMP effect occurs in emotional processing-whether the effect may occur in the earlier attention allocation stage or in the later evaluation stage. In this study, we examined the neural correlates of affect misattribution, using event-related potential (ERP) dividing the participants into two groups based on their tendency toward affect misattribution. The ERP results showed that the amplitude of P2 was larger for the prime at the parietal location in participants showing a low tendency to misattribution than for those showing a high tendency, while the effect of judging neutral targets amiss according to the primes was reflected in the late processing of targets (LPP). In addition, the topographic pattern analysis revealed that EPN-like component to targets was correlated with the difference of AMP tendency as well as P2 to primes and LPP to targets. Taken together, the mechanism of the affective misattribution was closely related to the attention allocation processing. Our findings provide neural evidence that evaluations of neutral targets are misattributed to emotional primes.

  20. Health Impact Assessment (HIA) and EnviroAtlas: Integrating Ecosystem Services into the Decision-Making Process-Guide

    EPA Science Inventory

    This document was created to highlight the many ways that the U.S. EPA EnviroAtlas suite of ecosystem services tools can be used to aid in the Health Impact Assessment (HIA) process. Ecosystems provide numerous services and benefits to individuals, communities, businesses, and ot...

  1. Spelling-to-sound correspondences affect acronym recognition processes.

    PubMed

    Playfoot, David; Izura, Cristina

    2015-01-01

    A large body of research has examined the factors that affect the speed with which words are recognized in lexical decision tasks. Nothing has yet been reported concerning the important factors in differentiating acronyms (e.g., BBC, HIV, NASA) from nonwords. It appears that this task poses little problem for skilled readers, in spite of the fact that acronyms have uncommon, even illegal, spellings in English. We used regression techniques to examine the role of a number of lexical and nonlexical variables known to be important in word processing in relation to lexical decision for acronym targets. Findings indicated that acronym recognition is affected by age of acquisition and imageability. In a departure from findings in word recognition, acronym recognition was not affected by frequency. Lexical decision responses for acronyms were also affected by the relationship between spelling and sound-a pattern not usually observed in word recognition. We argue that the complexity of acronym recognition means that the process draws phonological information in addition to semantics. PMID:25337636

  2. Elaboration of a video processing platform to analyze the temporal dynamics of hydrothermal ecosystems

    NASA Astrophysics Data System (ADS)

    Aron, M.; Sarrazin, J.; Sarradin, P.; Mercier, G.

    2010-12-01

    Located on oceanic ridges, hydrothermal ecosystems are characterized by strong physicochemical gradients and the presence of a unique fauna, sustained by microbial chemosynthesis. Several studies have shown that the spatial distribution and composition of vent faunal assemblages were strongly correlated to geological, physical and chemical processes at different spatial and temporal scales, but almost no data are available on the temporal dynamics of these peculiar ecosystems. The objective of our research is to develop a video processing platform to automatically extract the biological, physical and geological data from video imagery in order to study the dynamics of the fauna and its habitat in hydrothermal ecosystems. The video data was acquired from the Tempo-mini module deployed at 100m depth in the Saanich inlet (BC, Canada) and connected to the VENUS cable observatory (http://www.venus.uvic.ca/). This submarine color video-camera acquired four months of video footage, representing 487944 images of typical benthic habitat. A first manual extraction of the data allowed us to identify the key data available on a small subset of the video sequences. The objective of the new processing tool is to automatically extract these key data on the whole dataset, using unsupervized or lightly supervized image processing technique adapted to the specificity of submarines images. Firstly, all the moving objects in the video frames were segmented and labelled, allowing us to use statistical methods to process very large datasets. Secondly, computer vision techniques were used in order to get metric and 3D information from the images. For example, the speed of the moving objects and the image surface area were computed. The method implies the calibration of the camera with a calibration target, i.e. computing the projective geometric properties of the camera and the scene. Lastly, the developed tools will be integrated in a user-friendly processing platform that will be used

  3. Processes affecting the oceanic distributions of dissolved calcium and alkalinity

    SciTech Connect

    Shiller, A.M.; Gieskes, J.M.

    1980-05-20

    Recent studies of the CO/sub 2/ system have suggested that chemical processes in addition to the dissolution and precipitation of calcium carbonate affect the oceanic calcium and alkalinity distributions. Calcium and alkalinity data from the North Pacific have been examined both by using the simple physical-chemical model of previous workers and by a study involving the broader oceanographic context of these data. The simple model is shown to be an inadequate basis for these studies. Although a proton flux associated with organic decomposition may affect the alkalinity, previously reported deviations of calcium-alkalinity correlations from expected trends appear to be related to boundary processes that have been neglected rather than to this proton flux. The distribution of calcium in the surface waters of the Pacific Ocean is examined.

  4. African dust carries microbes across the ocean: are they affecting human and ecosystem health?

    USGS Publications Warehouse

    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.

  5. Groundwater-ocean interaction and its effects on coastal ecological processes - are there groundwater-dependant ecosystems in the coastal zone?

    NASA Astrophysics Data System (ADS)

    Stieglitz, T. C.

    2013-05-01

    Hydrological land-ocean connectivity is an important driver of coastal ecosystems. Rivers are obvious and visible pathways for terrestrial runoff. The critical role of surface water discharge from rivers to coastal ecosystems has been well documented. Hidden from view, 'downstream' effects of coastal (supra-tidal, intertidal and submarine) groundwater discharge are far less well understood. Whilst hydrological and geochemical processes associated with coastal groundwater discharge have received an increasing amount of scientific attention over the past decade or so, the effects of groundwater flow on productivity, composition, diversity and functioning of coastal ecosystems along the world's shorelines have received little attention to date. Coastal groundwater discharge includes both terrestrial (fresh) groundwater fluxes and the recirculation of seawater through sediments, analogous to hyporheic flow in rivers. I will present an overview over relevant coastal hydrological processes, and will illustrate their ecological effects on examples from diverse tropical coastal ecosystems, e.g. (1) perennial fresh groundwater discharge from coastal sand dune systems permitting growth of freshwater-dependent vegetation in the intertidal zone of the Great Barrier Reef (Australia), (2) recirculation of seawater through mangrove forest floors directly affecting tree health and providing a pathway for carbon export from these ecosystems, (3) the local hydrology of groundwater-fed coastal inlets on Mexico's Yucatan peninsula affecting the movement behaviour of and habitat use by the queen conch Strombus gigas, an economically important species in the Caribbean region. These examples for hydrological-ecological coupling in the coastal zone invite the question if we should not consider these coastal ecosystems to be groundwater-dependent, in analogy to groundwater-dependency in freshwater aquatic systems.

  6. Consequences of a simulated rapid ocean acidification event for benthic ecosystem processes and functions.

    PubMed

    Murray, Fiona; Widdicombe, Stephen; McNeill, C Louise; Solan, Martin

    2013-08-30

    Whilst the biological consequences of long-term, gradual changes in acidity associated with the oceanic uptake of atmospheric carbon dioxide (CO2) are increasingly studied, the potential effects of rapid acidification associated with a failure of sub-seabed carbon storage infrastructure have received less attention. This study investigates the effects of severe short-term (8days) exposure to acidified seawater on infaunal mediation of ecosystem processes (bioirrigation and sediment particle redistribution) and functioning (nutrient concentrations). Following acidification, individuals of Amphiura filiformis exhibited emergent behaviour typical of a stress response, which resulted in altered bioturbation, but limited changes in nutrient cycling. Under acidified conditions, A. filiformis moved to shallower depths within the sediment and the variability in occupancy depth reduced considerably. This study indicated that rapid acidification events may not be lethal to benthic invertebrates, but may result in behavioural changes that could have longer-term implications for species survival, ecosystem structure and functioning.

  7. How will ocean acidification affect Baltic sea ecosystems? an assessment of plausible impacts on key functional groups.

    PubMed

    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.

  8. Microbial processes in marine ecosystem models: state of the art and future prospective

    NASA Astrophysics Data System (ADS)

    Polimene, L.; Butenschon, M.; Blackford, J.; Allen, I.

    2012-12-01

    Heterotrophic bacteria play a key role in the marine biogeochemistry being the main consumer of dissolved organic matter (DOM) and the main producer of carbon dioxide (CO2) by respiration. Quantifying the carbon and energy fluxes within bacteria (i.e. production, respiration, overflow metabolism etc.) is therefore crucial for the assessment of the global ocean carbon and nutrient cycles. Consequently, the description of bacteria dynamic in ecosystem models is a key (although challenging) issue which cannot be overlooked if we want to properly simulate the marine environment. We present an overview of the microbial processes described in the European Sea Regional Ecosystem Model (ERSEM), a state of the art biogeochemical model resolving carbon and nutrient cycles (N, P, Si and Fe) within the low trophic levels (up to mesozooplankton) of the marine ecosystem. The description of the theoretical assumptions and philosophy underpinning the ERSEM bacteria sub-model will be followed by the presentation of some case studies highlighting the relevance of resolving microbial processes in the simulation of ecosystem dynamics at a local scale. Recent results concerning the implementation of ERSEM on a global ocean domain will be also presented. This latter exercise includes a comparison between simulations carried out with the full bacteria sub-model and simulations carried out with an implicit parameterization of bacterial activity. The results strongly underline the importance of explicitly resolved bacteria in the simulation of global carbon fluxes. Finally, a summary of the future developments along with issues still open on the topic will be presented and discussed.

  9. Disturbance Distance: Combining a process based ecosystem model and remote sensing data to map the vulnerability of U.S. forested ecosystems to potentially altered disturbance rates

    NASA Astrophysics Data System (ADS)

    Dolan, K. A.

    2015-12-01

    Disturbance plays a critical role in shaping the structure and function of forested ecosystems as well as the ecosystem services they provide, including but not limited to: carbon storage, biodiversity habitat, water quality and flow, and land atmosphere exchanges of energy and water. In addition, recent studies suggest that disturbance rates may increase in the future under altered climate and land use scenarios. Thus understanding how vulnerable forested ecosystems are to potential changes in disturbance rates is of high importance. This study calculated the theoretical threshold rate of disturbance for which forest ecosystems could no longer be sustained (λ*) across the Coterminous U.S. using an advanced process based ecosystem model (ED). Published rates of disturbance (λ) in 50 study sites were obtained from the North American Forest Disturbance (NAFD) program. Disturbance distance (λ* - λ) was calculated for each site by differencing the model based threshold under current climate conditions and average observed rates of disturbance over the last quarter century. Preliminary results confirm all sample forest sites have current average rates of disturbance below λ*, but there were interesting patterns in the recorded disturbance distances. In general western sites had much smaller disturbance distances, suggesting higher vulnerability to change, while eastern sites showed larger buffers. Ongoing work is being conducted to assess the vulnerability of these sites in the context of potential future changes by propagating scenarios of future climate and land-use change through the analysis.

  10. Modeling of hydroecological feedbacks predicts distinct classes of landscape pattern, process, and restoration potential in shallow aquatic ecosystems

    USGS Publications Warehouse

    Larsen, Laurel G.; Harvey, Judson W.

    2011-01-01

    In general, the stability of different wetland pattern types is most strongly related to factors controlling the erosion and deposition of sediment at vegetation patch edges, the magnitude of sediment redistribution by flow, patch elevation relative to water level, and the variability of erosion rates in vegetation patches with low flow-resistance. As we exemplify in our case-study of the Everglades ridge and slough landscape, feedback between flow and vegetation also causes hysteresis in landscape evolution trajectories that will affect the potential for landscape restoration. Namely, even if the hydrologic conditions that historically produced higher flows are restored, degraded portions of the ridge and slough landscape are unlikely to revert to their former patterning. As wetlands and floodplains worldwide become increasingly threatened by climate change and urbanization, the greater mechanistic understanding of landscape pattern and process that our analysis provides will improve our ability to forecast and manage the behavior of these ecosystems.

  11. Neural Correlates of Affect Processing and Aggression in Methamphetamine Dependence

    PubMed Central

    Payer, Doris E.; Lieberman, Matthew D.; London, Edythe D.

    2012-01-01

    Context Methamphetamine abuse is associated with high rates of aggression, but few studies have addressed the contributing neurobiological factors. Objective To quantify aggression, investigate function of the amygdala and prefrontal cortex, and assess relationships between brain function and behavior in methamphetamine-dependent individuals. Design In a case-control study, aggression and brain activation were compared between methamphetamine-dependent and control participants. Setting Participants were recruited from the general community to an academic research center. Participants Thirty-nine methamphetamine-dependent volunteers (16 women) who were abstinent for 7 to 10 days and 37 drug-free control volunteers (18 women) participated in the study; subsets completed self-report and behavioral measures. Functional magnetic resonance imaging (fMRI) was performed on 25 methamphetamine-dependent and 23 control participants. Main outcome measures We measured self-reported and perpetrated aggression, and self-reported alexithymia. Brain activation was assessed using fMRI during visual processing of facial affect (affect matching), and symbolic processing (affect labeling), the latter representing an incidental form of emotion regulation. Results Methamphetamine-dependent participants self-reported more aggression and alexithymia than control participants and escalated perpetrated aggression more following provocation. Alexithymia scores correlated with measures of aggression. During affect matching, fMRI showed no differences between groups in amygdala activation, but found lower activation in methamphetamine-dependent than control participants in bilateral ventral inferior frontal gyrus. During affect labeling, participants recruited dorsal inferior frontal gyrus and exhibited decreased amygdala activity, consistent with successful emotion regulation; there was no group difference in this effect. The magnitude of decrease in amygdala activity during affect labeling

  12. Application of ultrasound processed images in space: assessing diffuse affectations

    NASA Astrophysics Data System (ADS)

    Pérez-Poch, A.; Bru, C.; Nicolau, C.

    The purpose of this study was to evaluate diffuse affectations in the liver using texture image processing techniques. Ultrasound diagnose equipments are the election of choice to be used in space environments as they are free from hazardous effects on health. However, due to the need for highly trained radiologists to assess the images, this imaging method is mainly applied on focal lesions rather than on non-focal ones. We have conducted a clinical study on 72 patients with different degrees of chronic hepatopaties and a group of control of 18 individuals. All subjects' clinical reports and results of biopsies were compared to the degree of affectation calculated by our computer system , thus validating the method. Full statistical results are given in the present paper showing a good correlation (r=0.61) between pathologist's report and analysis of the heterogenicity of the processed images from the liver. This computer system to analyze diffuse affectations may be used in-situ or via telemedicine to the ground.

  13. Habitat complexity influences fine scale hydrological processes and the incidence of stormwater runoff in managed urban ecosystems.

    PubMed

    Ossola, Alessandro; Hahs, Amy Kristin; Livesley, Stephen John

    2015-08-15

    Urban ecosystems have traditionally been considered to be pervious features of our cities. Their hydrological properties have largely been investigated at the landscape scale and in comparison with other urban land use types. However, hydrological properties can vary at smaller scales depending upon changes in soil, surface litter and vegetation components. Management practices can directly and indirectly affect each of these components and the overall habitat complexity, ultimately affecting hydrological processes. This study aims to investigate the influence that habitat components and habitat complexity have upon key hydrological processes and the implications for urban habitat management. Using a network of urban parks and remnant nature reserves in Melbourne, Australia, replicate plots representing three types of habitat complexity were established: low-complexity parks, high-complexity parks, and high-complexity remnants. Saturated soil hydraulic conductivity in low-complexity parks was an order of magnitude lower than that measured in the more complex habitat types, due to fewer soil macropores. Conversely, soil water holding capacity in low-complexity parks was significantly higher compared to the two more complex habitat types. Low-complexity parks would generate runoff during modest precipitation events, whereas high-complexity parks and remnants would be able to absorb the vast majority of rainfall events without generating runoff. Litter layers on the soil surface would absorb most of precipitation events in high-complexity parks and high-complexity remnants. To minimize the incidence of stormwater runoff from urban ecosystems, land managers could incrementally increase the complexity of habitat patches, by increasing canopy density and volume, preserving surface litter and maintaining soil macropore structure.

  14. Simulations of Ecosystem Hydrological Processes Using a Unified Multi-Scale Model

    SciTech Connect

    Yang, Xiaofan; Liu, Chongxuan; Fang, Yilin; Hinkle, Ross; Li, Hongyi; Bailey, Vanessa L.; Bond-Lamberty, Benjamin

    2015-01-24

    This paper presents a unified multi-scale model (UMSM) that we developed to simulate hydrological processes in an ecosystem containing both surface water and groundwater. The UMSM approach modifies the Navier–Stokes equation by adding a Darcy force term to formulate a single set of equations to describe fluid momentum and uses a generalized equation to describe fluid mass balance. The advantage of the approach is that the single set of the equations can describe hydrological processes in both surface water and groundwater where different models are traditionally required to simulate fluid flow. This feature of the UMSM significantly facilitates modelling of hydrological processes in ecosystems, especially at locations where soil/sediment may be frequently inundated and drained in response to precipitation, regional hydrological and climate changes. In this paper, the UMSM was benchmarked using WASH123D, a model commonly used for simulating coupled surface water and groundwater flow. Disney Wilderness Preserve (DWP) site at the Kissimmee, Florida, where active field monitoring and measurements are ongoing to understand hydrological and biogeochemical processes, was then used as an example to illustrate the UMSM modelling approach. The simulations results demonstrated that the DWP site is subject to the frequent changes in soil saturation, the geometry and volume of surface water bodies, and groundwater and surface water exchange. All the hydrological phenomena in surface water and groundwater components including inundation and draining, river bank flow, groundwater table change, soil saturation, hydrological interactions between groundwater and surface water, and the migration of surface water and groundwater interfaces can be simultaneously simulated using the UMSM. Overall, the UMSM offers a cross-scale approach that is particularly suitable to simulate coupled surface and ground water flow in ecosystems with strong surface water and groundwater interactions.

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

    SciTech Connect

    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.

  16. Environmental changes affect the assembly of soil bacterial community primarily by mediating stochastic processes.

    PubMed

    Zhang, Ximei; Johnston, Eric R; Liu, Wei; Li, Linghao; Han, Xingguo

    2016-01-01

    Both 'species fitness difference'-based deterministic processes, such as competitive exclusion and environmental filtering, and 'species fitness difference'-independent stochastic processes, such as birth/death and dispersal/colonization, can influence the assembly of soil microbial communities. However, how both types of processes are mediated by anthropogenic environmental changes has rarely been explored. Here we report a novel and general pattern that almost all anthropogenic environmental changes that took place in a grassland ecosystem affected soil bacterial community assembly primarily through promoting or restraining stochastic processes. We performed four experiments mimicking 16 types of environmental changes and separated the compositional variation of soil bacterial communities caused by each environmental change into deterministic and stochastic components, with a recently developed method. Briefly, because the difference between control and treatment communities is primarily caused by deterministic processes, the deterministic change was quantified as (mean compositional variation between treatment and control) - (mean compositional variation within control). The difference among replicate treatment communities is primarily caused by stochastic processes, so the stochastic change was estimated as (mean compositional variation within treatment) - (mean compositional variation within control). The absolute of the stochastic change was greater than that of the deterministic change across almost all environmental changes, which was robust for both taxonomic and functional-based criterion. Although the deterministic change may become more important as environmental changes last longer, our findings showed that changes usually occurred through mediating stochastic processes over 5 years, challenging the traditional determinism-dominated view.

  17. A Screening-Level Approach for Comparing Risks Affecting Aquatic Ecosystem Services over Socio-Environmental Gradients

    NASA Astrophysics Data System (ADS)

    Harmon, T. C.; Conde, D.; Villamizar, S. R.; Reid, B.; Escobar, J.; Rusak, J.; Hoyos, N.; Scordo, F.; Perillo, G. M.; Piccolo, M. C.; Zilio, M.; Velez, M.

    2015-12-01

    Assessing risks to aquatic ecosystems services (ES) is challenging and time-consuming, and effective strategies for prioritizing more detailed assessment efforts are needed. We propose a screening-level risk analysis (SRA) approach that scales ES risk using socioeconomic and environmental indices to capture anthropic and climatic pressures, as well as the capacity for institutional responses to those pressures. The method considers ES within a watershed context, and uses expert input to prioritize key services and the associated pressures that threaten them. The SRA approach focuses on estimating ES risk affect factors, which are the sum of the intensity factors for all hazards or pressures affecting the ES. We estimate the pressure intensity factors in a novel manner, basing them on the nation's (i) human development (proxied by Inequality-adjusted Human Development Index, IHDI), (ii) environmental regulatory and monitoring state (Environmental Performance Index, EPI) and (iii) the current level of water stress in the watershed (baseline water stress, BWS). Anthropic intensity factors for future conditions are derived from the baseline values based on the nation's 10-year trend in IHDI and EPI; ES risks in nations with stronger records of change are rewarded more/penalized less in estimates for good/poor future management scenarios. Future climatic intensity factors are tied to water stress estimates based on two general circulation model (GCM) outcomes. We demonstrate the method for an international array of six sites representing a wide range of socio-environmental settings. The outcomes illustrate novel consequences of the scaling scheme. Risk affect factors may be greater in a highly developed region under intense climatic pressure, or in less well-developed regions due to human factors (e.g., poor environmental records). As a screening-level tool, the SRA approach offers considerable promise for ES risk comparisons among watersheds and regions so that

  18. Processing of affective speech prosody is impaired in Asperger syndrome.

    PubMed

    Korpilahti, Pirjo; Jansson-Verkasalo, Eira; Mattila, Marja-Leena; Kuusikko, Sanna; Suominen, Kalervo; Rytky, Seppo; Pauls, David L; Moilanen, Irma

    2007-09-01

    Many people with the diagnosis of Asperger syndrome (AS) show poorly developed skills in understanding emotional messages. The present study addressed discrimination of speech prosody in children with AS at neurophysiological level. Detection of affective prosody was investigated in one-word utterances as indexed by the N1 and the mismatch negativity (MMN) of auditory event-related potentials (ERPs). Data from fourteen boys with AS were compared with those for thirteen typically developed boys. These results suggest atypical neural responses to affective prosody in children with AS and their fathers, especially over the RH, and that this impairment can already be seen at low-level information processes. Our results provide evidence for familial patterns of abnormal auditory brain reactions to prosodic features of speech.

  19. Estimating California ecosystem carbon change using process model and land cover disturbance data: 1951-2000

    USGS Publications Warehouse

    Liu, J.; Vogelmann, J.E.; Zhu, Z.; Key, C.H.; Sleeter, B.M.; Price, D.T.; Chen, J.M.; Cochrane, M.A.; Eidenshink, J.C.; Howard, S.M.; Bliss, N.B.; Jiang, H.

    2011-01-01

    Land use change, natural disturbance, and climate change directly alter ecosystem productivity and carbon stock level. The estimation of ecosystem carbon dynamics depends on the quality of land cover change data and the effectiveness of the ecosystem models that represent the vegetation growth processes and disturbance effects. We used the Integrated Biosphere Simulator (IBIS) and a set of 30- to 60-m resolution fire and land cover change data to examine the carbon changes of California's forests, shrublands, and grasslands. Simulation results indicate that during 1951-2000, the net primary productivity (NPP) increased by 7%, from 72.2 to 77.1TgCyr-1 (1 teragram=1012g), mainly due to CO2 fertilization, since the climate hardly changed during this period. Similarly, heterotrophic respiration increased by 5%, from 69.4 to 73.1TgCyr-1, mainly due to increased forest soil carbon and temperature. Net ecosystem production (NEP) was highly variable in the 50-year period but on average equalled 3.0TgCyr-1 (total of 149TgC). As with NEP, the net biome production (NBP) was also highly variable but averaged -0.55TgCyr-1 (total of -27.3TgC) because NBP in the 1980s was very low (-5.34TgCyr-1). During the study period, a total of 126Tg carbon were removed by logging and land use change, and 50Tg carbon were directly removed by wildland fires. For carbon pools, the estimated total living upper canopy (tree) biomass decreased from 928 to 834TgC, and the understory (including shrub and grass) biomass increased from 59 to 63TgC. Soil carbon and dead biomass carbon increased from 1136 to 1197TgC. Our analyses suggest that both natural and human processes have significant influence on the carbon change in California. During 1951-2000, climate interannual variability was the key driving force for the large interannual changes of ecosystem carbon source and sink at the state level, while logging and fire were the dominant driving forces for carbon balances in several specific

  20. Agricultural management affects evolutionary processes in a migratory songbird

    USGS Publications Warehouse

    Perlut, N.G.; Freeman-Gallant, C. R.; Strong, A.M.; Donovan, T.M.; Kilpatrick, C.W.; Zalik, N.J.

    2008-01-01

    Hay harvests have detrimental ecological effects on breeding songbirds, as harvesting results in nest failure. Importantly, whether harvesting also affects evolutionary processes is not known. We explored how hay harvest affected social and genetic mating patterns, and thus, the overall opportunity for sexual selection and evolutionary processes for a ground-nesting songbird, the Savannah sparrow (Passerculus sandwichensis). On an unharvested field, 55% of females were in polygynous associations, and social polygyny was associated with greater rates of extra-pair paternity (EPP). In this treatment, synchrony explained variation in EPP rates, as broods by more synchronous females had more EPP than broods by asynchronous females. In contrast, on a harvested field, simultaneous nest failure caused by haying dramatically decreased the overall incidence of EPP by increasing the occurrence of social monogamy and, apparently, the ability of polygynous males to maintain paternity in their own nests. Despite increased social and genetic monogamy, these haying-mediated changes in mating systems resulted in greater than twofold increase in the opportunity for sexual selection. This effect arose, in part, from a 30% increase in the variance associated with within-pair fertilization success, relative to the unharvested field. This effect was caused by a notable increase (+110%) in variance associated with the quality of social mates following simultaneous nest failure. Because up to 40% of regional habitat is harvested by early June, these data may demonstrate a strong population-level effect on mating systems, sexual selection, and consequently, evolutionary processes. ?? 2008 The Authors.

  1. Processes affecting the remediation of chromium-contaminated sites.

    PubMed Central

    Palmer, C D; Wittbrodt, P R

    1991-01-01

    The remediation of chromium-contaminated sites requires knowledge of the processes that control the migration and transformation of chromium. Advection, dispersion, and diffusion are physical processes affecting the rate at which contaminants can migrate in the subsurface. Heterogeneity is an important factor that affects the contribution of each of these mechanisms to the migration of chromium-laden waters. Redox reactions, chemical speciation, adsorption/desorption phenomena, and precipitation/dissolution reactions control the transformation and mobility of chromium. The reduction of CrVI to CrIII can occur in the presence of ferrous iron in solution or in mineral phases, reduced sulfur compounds, or soil organic matter. At neutral to alkaline pH, the CrIII precipitates as amorphous hydroxides or forms complexes with organic matter. CrIII is oxidized by manganese dioxide, a common mineral found in many soils. Solid-phase precipitates of hexavalent chromium such as barium chromate can serve either as sources or sinks for CrVI. Adsorption of CrVI in soils increases with decreasing chromium concentration, making it more difficult to remove the chromium as the concentration decreases during pump-and-treat remediation. Knowledge of these chemical and physical processes is important in developing and selecting effective, cost-efficient remediation designs for chromium-contaminated sites. PMID:1935849

  2. Species effects on ecosystem processes are modified by faunal responses to habitat composition.

    PubMed

    Bulling, Mark T; Solan, Martin; Dyson, Kirstie E; Hernandez-Milian, Gema; Luque, Patricia; Pierce, Graham J; Raffaelli, Dave; Paterson, David M; White, Piran C L

    2008-12-01

    Heterogeneity is a well-recognized feature of natural environments, and the spatial distribution and movement of individual species is primarily driven by resource requirements. In laboratory experiments designed to explore how different species drive ecosystem processes, such as nutrient release, habitat heterogeneity is often seen as something which must be rigorously controlled for. Most small experimental systems are therefore spatially homogeneous, and the link between environmental heterogeneity and its effects on the redistribution of individuals and species, and on ecosystem processes, has not been fully explored. In this paper, we used a mesocosm system to investigate the relationship between habitat composition, species movement and sediment nutrient release for each of four functionally contrasting species of marine benthic invertebrate macrofauna. For each species, various habitat configurations were generated by selectively enriching patches of sediment with macroalgae, a natural source of spatial variability in intertidal mudflats. We found that the direction and extent of faunal movement between patches differs with species identity, density and habitat composition. Combinations of these factors lead to concomitant changes in nutrient release, such that habitat composition effects are modified by species identity (in the case of NH4-N) and by species density (in the case of PO4-P). It is clear that failure to accommodate natural patterns of spatial heterogeneity in such studies may result in an incomplete understanding of system behaviour. This will be particularly important for future experiments designed to explore the effects of species richness on ecosystem processes, where the complex interactions reported here for single species may be compounded when species are brought together in multi-species combinations.

  3. Effects of climate and lifeform on dry matter yield (epsilon) from simulations using BIOME BGC. [ecosystem process model for vegetation biomass production using daily absorbed photosynthetically active radiation

    NASA Technical Reports Server (NTRS)

    Hunt, E. R., Jr.; Running, Steven W.

    1992-01-01

    An ecosystem process simulation model, BIOME-BGC, is used in a sensitivity analysis to determine the factors that may cause the dry matter yield (epsilon) and annual net primary production to vary for different ecosystems. At continental scales, epsilon is strongly correlated with annual precipitation. At a single location, year-to-year variation in net primary production (NPP) and epsilon is correlated with either annual precipitation or minimum air temperatures. Simulations indicate that forests have lower epsilon than grasslands. The most sensitive parameter affecting forest epsilon is the total amount of living woody biomass, which affects NPP by increasing carbon loss by maintenance respiration. A global map of woody biomass should significantly improve estimates of global NPP using remote sensing.

  4. Biodiversity and ecosystem processes in shallow coastal waters: an experimental approach

    NASA Astrophysics Data System (ADS)

    Raffaelli, D.; Emmerson, M.; Solan, M.; Biles, C.; Paterson, D.

    2003-03-01

    The relationship between biodiversity and ecological processes is currently the focus of considerable research effort, made all the more urgent by the rate of biodiversity loss world-wide. Rigorous experimental approaches to this question have been dominated by terrestrial ecologists, but shallow-water marine systems offer great opportunities by virtue of their relative ease of manipulation, fast response times and well-understood effects of macrofauna on sediment processes. In this paper, we describe a series of experiments whereby species richness has been manipulated in a controlled way and the concentrations of nutrients (ammonium, nitrate and phosphate) in the overlying water measured under these different treatments. The results indicate variable effects of species and location on ecosystem processes, and are discussed in the context of emerging mainstream ecological theory on biodiversity and ecosystem relations. Extensions of the application of the experimental approach to species-rich, large-scale benthic systems are discussed and the potential for novel analyses of existing data sets is highlighted.

  5. Effects of processing style on responsiveness to affective stimuli and processing fluency.

    PubMed

    Dijkstra, Koen A; van der Pligt, Joop; van Kleef, Gerben A

    2014-01-01

    In the present study, we provide direct evidence for effects of global versus local processing on responsiveness to and reliance on affective information in judgement and decision-making. Results of Experiments 1 and 2 showed an increased responsiveness to affective stimuli among participants in a global processing mode. Experiment 3 showed similar effects for processing fluency; participants adopting a global processing style showed an increased reliance on fluency. Experiment 4 replicated our findings in a more mundane judgement task in which participants judged apartments. We discuss our findings in relation to the distinction between intuitive versus deliberative modes of thinking.

  6. Integration of coral reef ecosystem process studies and remote sensing: Chapter 5

    USGS Publications Warehouse

    Brook, John; Yates, Kimberly; Halley, Robert

    2006-01-01

    anthropogenic causes (Brown, 1988). Models of coral reef ecosystems, parameterized by process measurements and scaled in time-space using remote sensing, have the potential to address pressing research questions that are central to devising valid management strategies (Grigg el al., 1984; Hatcher, 1997b). To attain this goal, ecosystem-level models that integrate studies of physical and chemical forcing with observed biological and geological responses are required. This interdisciplinary approach to understanding reef biogeochemical dynamics can allow investigations that integrate the scales of time and space (Hatcher, 1997a), thereby enabling prediction of coral reef change (Andréfouët and Payri, 2001). In turn, prediction of holistic ecosystem function within various environmental focusing scenarios has substantial promise in mitigating future disturbance. Indeed, management of coral reefs at the ecosystem level has been suggested as the only meaningful approach to preserving coral reefs (Bohnsack and Ault, 1996; Christensen et al., 1996).

  7. Development of brain mechanisms for processing affective touch

    PubMed Central

    Björnsdotter, Malin; Gordon, Ilanit; Pelphrey, Kevin A.; Olausson, Håkan; Kaiser, Martha D.

    2014-01-01

    Affective tactile stimulation plays a key role in the maturation of neural circuits, but the development of brain mechanisms processing touch is poorly understood. We therefore used functional magnetic resonance imaging (fMRI) to study brain responses to soft brush stroking of both glabrous (palm) and hairy (forearm) skin in healthy children (5–13 years), adolescents (14–17 years), and adults (25–35 years). Adult-defined regions-of-interests in the primary somatosensory cortex (SI), secondary somatosensory cortex (SII), insular cortex and right posterior superior temporal sulcus (pSTS) were significantly and similarly activated in all age groups. Whole-brain analyses revealed that responses in the ipsilateral SII were positively correlated with age in both genders, and that responses in bilateral regions near the pSTS correlated significantly and strongly with age in females but not in males. These results suggest that brain mechanisms associated with both sensory-discriminative and affective-motivational aspects of touch are largely established in school-aged children, and that there is a general continuing maturation of SII and a female-specific increase in pSTS sensitivity with age. Our work establishes a groundwork for future comparative studies of tactile processing in developmental disorders characterized by disrupted social perception such as autism. PMID:24550800

  8. Processes affecting the distribution and speciation of selenium in seawater

    SciTech Connect

    Cutter, G.A.

    1982-01-01

    The analyses of dissolved selenium species in the Pacific Ocean and anoxic waters of the Saanich Inlet, selenium in fluxing particles, and the regeneration of selenium from biogenic matter has been undertaken in order to evaluate the processes affecting selenium in the ocean. Analyses of oceanic surface waters show selenite to be severely depleted, and the degree of selenate depletion, a function of the oceanic regime (i.e. most depleted in oligotrophic regions). Both species are enriched in deeper waters with an approximately 60:40 ratio of Se +6 to +4. A major species in surface waters and the upper thermocline is organic selenide. A secondary maximum of organic selenide is seen in the suboxic oxygen minimum of the eastern tropical Pacific, while selenite shows a negative anomaly. The regeneration of selenium from biogenic matter shows a multistep behavior, with organic selenide being released rapidly and primarily, selenite and selenate being produced by the slow oxidation of this fraction. Selenium in the ocean is affected by several processes. First organisms preferentially take-up selenite over selenate. This incorporation of selenium into biological material involves reduction to selenide. As selenium is regenerated from biogenic matter, first organic selenide is released, which in turn oxidizes to selenite, which then oxidizes very slowly to selenate. Finally, selenium does appear to undergo redox reactions in anoxic systems, but the products of the reactions remain unidentified.

  9. Methylmercury in Marine Ecosystems: Spatial Patterns and Processes of Production, Bioaccumulation, and Biomagnification

    PubMed Central

    Chen, Celia; Amirbahman, Aria; Fisher, Nicholas; Harding, Gareth; Lamborg, Carl; Nacci, Diane; Taylor, David

    2008-01-01

    The spatial variation of MeHg production, bioaccumulation and biomagnification in marine food webs is poorly characterized but critical to understanding the links between sources and higher trophic levels such as fish that are ultimately vectors of human and wildlife exposure. This paper discusses both large and local scale processes controlling Hg supply, methylation, bioaccumulation and transfer in marine ecosystems. While global estimates of Hg supply suggest important open ocean reservoirs of MeHg, only coastal processes and food webs are known sources of MeHg production, bioaccumulation, and bioadvection. The patterns observed to date suggest that not all sources and biotic receptors are spatially linked and that physical and ecological processes are important in transferring MeHg from source regions to bioaccumulation in marine food webs and from lower to higher trophic levels. PMID:19015919

  10. Nutrient vectors and riparian nutrient processing in African semiarid savanna ecosystems

    USGS Publications Warehouse

    Jacobs, Shayne M.; Bechtold, J.S.; Biggs, Harry C.; Grimm, N. B.; McClain, M.E.; Naiman, R.J.; Perakis, Steven S.; Pinay, G.; Scholes, M.C.

    2007-01-01

    This review article describes vectors for nitrogen and phosphorus delivery to riparian zones in semiarid African savannas, the processing of nutrients in the riparian zone and the effect of disturbance on these processes. Semiarid savannas exhibit sharp seasonality, complex hillslope hydrology and high spatial heterogeneity, all of which ultimately impact nutrient fluxes between riparian, upland and aquatic environments. Our review shows that strong environmental drivers such as fire and herbivory enhance nitrogen, phosphorus and sediment transport to lower slope positions by shaping vegetative patterns. These vectors differ significantly from other arid and semiarid ecosystems, and from mesic ecosystems where the impact of fire and herbivory are less pronounced and less predictable. Also unique is the presence of sodic soils in certain hillslopes, which substantially alters hydrological flowpaths and may act as a trap where nitrogen is immobilized while sediment and phosphorus transport is enhanced. Nutrients and sediments are also deposited in the riparian zone during seasonal, intermittent floods while, during the dry season, subsurface movement of water from the stream into riparian soils and vegetation further enrich riparian zones with nutrients. As is found in mesic ecosystems, nutrients are immobilized in semiarid riparian corridors through microbial and plant uptake, whereas dissimilatory processes such as denitrification may be important where labile nitrogen and carbon are in adequate supply and physical conditions are suitablea??such as in seeps, wallows created by animals, ephemeral wetlands and stream edges. Interaction between temporal hydrologic connectivity and spatial heterogeneity are disrupted by disturbances such as large floods and extended droughts, which may convert certain riparian patches from sinks to sources for nitrogen and phosphorus. In the face of increasing anthropogenic pressure, the scientific challenges are to provide a basic

  11. Affective and executive network processing associated with persuasive antidrug messages.

    PubMed

    Ramsay, Ian S; Yzer, Marco C; Luciana, Monica; Vohs, Kathleen D; MacDonald, Angus W

    2013-07-01

    Previous research has highlighted brain regions associated with socioemotional processes in persuasive message encoding, whereas cognitive models of persuasion suggest that executive brain areas may also be important. The current study aimed to identify lateral prefrontal brain areas associated with persuasive message viewing and understand how activity in these executive regions might interact with activity in the amygdala and medial pFC. Seventy adolescents were scanned using fMRI while they watched 10 strongly convincing antidrug public service announcements (PSAs), 10 weakly convincing antidrug PSAs, and 10 advertisements (ads) unrelated to drugs. Antidrug PSAs compared with nondrug ads more strongly elicited arousal-related activity in the amygdala and medial pFC. Within antidrug PSAs, those that were prerated as strongly persuasive versus weakly persuasive showed significant differences in arousal-related activity in executive processing areas of the lateral pFC. In support of the notion that persuasiveness involves both affective and executive processes, functional connectivity analyses showed greater coactivation between the lateral pFC and amygdala during PSAs known to be strongly (vs. weakly) convincing. These findings demonstrate that persuasive messages elicit activation in brain regions responsible for both emotional arousal and executive control and represent a crucial step toward a better understanding of the neural processes responsible for persuasion and subsequent behavior change.

  12. Major hydrogeochemical processes in an acid mine drainage affected estuary.

    PubMed

    Asta, Maria P; Calleja, Maria Ll; Pérez-López, Rafael; Auqué, Luis F

    2015-02-15

    This study provides geochemical data with the aim of identifying and quantifying the main processes occurring in an Acid Mine Drainage (AMD) affected estuary. With that purpose, water samples of the Huelva estuary were collected during a tidal half-cycle and ion-ion plots and geochemical modeling were performed to obtain a general conceptual model. Modeling results indicated that the main processes responsible for the hydrochemical evolution of the waters are: (i) the mixing of acid fluvial water with alkaline ocean water; (ii) precipitation of Fe oxyhydroxysulfates (schwertmannite) and hydroxides (ferrihydrite); (iii) precipitation of Al hydroxysulfates (jurbanite) and hydroxides (amorphous Al(OH)3); (iv) dissolution of calcite; and (v) dissolution of gypsum. All these processes, thermodynamically feasible in the light of their calculated saturation states, were quantified by mass-balance calculations and validated by reaction-path calculations. In addition, sorption processes were deduced by the non-conservative behavior of some elements (e.g., Cu and Zn). PMID:25530015

  13. Biogeochemical cycles of Chernobyl-born radionuclides in the contaminated forest ecosystems: long-term dynamics of the migration processes

    NASA Astrophysics Data System (ADS)

    Shcheglov, Alexey; Tsvetnova, Ol'ga; Klyashtorin, Alexey

    2013-04-01

    Biogeochemical migration is a dominant factor of the radionuclide transport through the biosphere. In the early XX century, V.I. Vernadskii, a Russian scientist known, noted about a special role living things play in transport and accumulation of natural radionuclide in various environments. The role of biogeochemical processes in migration and redistribution of technogenic radionuclides is not less important. In Russia, V. M. Klechkovskii and N.V. Timofeev-Ressovskii showed some important biogeochemical aspects of radionuclide migration by the example of global fallout and Kyshtym accident. Their followers, R.M. Alexakhin, M.A. Naryshkin, N.V. Kulikov, F.A. Tikhomirov, E.B. Tyuryukanova, and others also contributed a lot to biogeochemistry of radionuclides. In the post-Chernobyl period, this area of knowledge received a lot of data that allowed building the radioactive element balance and flux estimation in various biogeochemical cycles [Shcheglov et al., 1999]. Regrettably, many of recent radioecological studies are only focused on specific radionuclide fluxes or pursue some applied tasks, missing the holistic approach. Most of the studies consider biogeochemical fluxes of radioactive isotopes in terms of either dose estimation or radionuclide migration rates in various food chains. However, to get a comprehensive picture and develop a reliable forecast of environmental, ecological, and social consequences of radioactive pollution in a vast contaminated area, it is necessary to investigate all the radionuclide fluxes associated with the biogeochemical cycles in affected ecosystems. We believe such an integrated approach would be useful to study long-term environmental consequences of the Fukushima accident as well. In our long-term research, we tried to characterize the flux dynamics of the Chernobyl-born radionuclides in the contaminated forest ecosystems and landscapes as a part of the integrated biogeochemical process. Our field studies were started in June of

  14. Towards Predictive Modeling of Information Processing in Microbial Ecosystems With Quorum-Sensing Interactions

    NASA Astrophysics Data System (ADS)

    Yusufaly, Tahir; Boedicker, James

    Bacteria communicate using external chemical signals in a process known as quorum sensing. However, the efficiency of this communication is reduced by both limitations on the rate of diffusion over long distances and potential interference from neighboring strains. Therefore, having a framework to quantitatively predict how spatial structure and biodiversity shape information processing in bacterial colonies is important, both for understanding the evolutionary dynamics of natural microbial ecosystems, and for the rational design of synthetic ecosystems with desired computational properties. As a first step towards these goals, we implement a reaction-diffusion model to study the dynamics of a LuxI/LuxR quorum sensing circuit in a growing bacterial population. The spatiotemporal concentration profile of acyl-homoserine lactone (AHL) signaling molecules is analyzed, and used to define a measure of physical and functional signaling network connectivity. From this, we systematically investigate how different initial distributions of bacterial populations influence the subsequent efficiency of collective long-range signal propagation in the population. We compare our results with known experimental data, and discuss limitations and extensions to our modeling framework.-/abstract-

  15. The "Musical Emotional Bursts": a validated set of musical affect bursts to investigate auditory affective processing.

    PubMed

    Paquette, Sébastien; Peretz, Isabelle; Belin, Pascal

    2013-01-01

    The Musical Emotional Bursts (MEB) consist of 80 brief musical executions expressing basic emotional states (happiness, sadness and fear) and neutrality. These musical bursts were designed to be the musical analog of the Montreal Affective Voices (MAV)-a set of brief non-verbal affective vocalizations portraying different basic emotions. The MEB consist of short (mean duration: 1.6 s) improvisations on a given emotion or of imitations of a given MAV stimulus, played on a violin (10 stimuli × 4 [3 emotions + neutral]), or a clarinet (10 stimuli × 4 [3 emotions + neutral]). The MEB arguably represent a primitive form of music emotional expression, just like the MAV represent a primitive form of vocal, non-linguistic emotional expression. To create the MEB, stimuli were recorded from 10 violinists and 10 clarinetists, and then evaluated by 60 participants. Participants evaluated 240 stimuli [30 stimuli × 4 (3 emotions + neutral) × 2 instruments] by performing either a forced-choice emotion categorization task, a valence rating task or an arousal rating task (20 subjects per task); 40 MAVs were also used in the same session with similar task instructions. Recognition accuracy of emotional categories expressed by the MEB (n:80) was lower than for the MAVs but still very high with an average percent correct recognition score of 80.4%. Highest recognition accuracies were obtained for happy clarinet (92.0%) and fearful or sad violin (88.0% each) MEB stimuli. The MEB can be used to compare the cerebral processing of emotional expressions in music and vocal communication, or used for testing affective perception in patients with communication problems. PMID:23964255

  16. Breathing and affective picture processing across the adult lifespan.

    PubMed

    Gomez, Patrick; Filippou, Dimitra; Pais, Bruno; von Gunten, Armin; Danuser, Brigitta

    2016-09-01

    The present study investigated differences between healthy younger, middle-aged, and older adults in their respiratory responses to pictures of different valence and arousal. Expiratory time shortened and end-tidal PCO2 decreased with increasing arousal in all age groups; yet, compared to younger adults, older adults' overall change from baseline was smaller for expiratory time and larger for end-tidal PCO2. Contrary to their younger counterparts, older adults' inspiratory time did not shorten with increasing arousal. Inspiratory duty cycle did not covary with affective ratings for younger adults, increased with unpleasantness for middle-aged adults, and increased with arousal for older adults. Thoracic breathing increased with increasing unpleasantness only among older adults. Age had no effects on mean inspiratory flow and minute ventilation, which both augmented as arousal increased. We discuss how age effects on respiratory response magnitude and pattern may depend on age-associated biological changes or reflect age-related differences in emotional processing.

  17. Processes Controlling Temporal Changes in Agriculturally-Affected Groundwater

    NASA Astrophysics Data System (ADS)

    Burow, K. R.; Belitz, K.; Jurgens, B. C.

    2014-12-01

    The National Water Quality Assessment (NAWQA) program of the U.S. Geological Survey includes assessment of groundwater-quality changes with time. To better understand changes at a national scale, NAWQA has implemented smaller scale flow-path studies to evaluate the processes affecting these changes. Flow path studies are designed to sample groundwater of different ages. Wells are sampled for a suite of constituents, including tracers of groundwater age. In the 1990s, a 4.6 km transect of monitoring wells was installed near Fresno in the southern Central Valley of California. The region is dominated by intensive agriculture. The wells were sampled in 1994-95, 2003, and 2013 to provide data on changes in water quality and groundwater age. In 2013, the flow path was extended to a regional scale (30 km) by using existing production wells. Preliminary interpretation of the local-scale flow path indicates that nitrate concentrations in the upper 25 m of the aquifer are higher than the USEPA Maximum Contaminant Level (MCL) for drinking water and variably increase or decrease with time. At intermediate depths (25-40 m), nitrate concentrations are lower and show small to moderate increases. The legacy pesticide 1,2-dibromo-3-chloropropane (DBCP) is degrading at a half-life of about 4-6 years. DBCP is present above the MCL at intermediate depths even though it is has been banned from use for more than 30 years. Both nitrate and DBCP appear to be moving vertically downward through the aquifer. Whereas uranium concentrations are generally below the MCL in the local-scale flow path, concentrations increase along the regional transect, with concentrations nearly an order of magnitude above the MCL in some wells. Further evaluation of processes affecting these constituents (such as source, redox, and mobilization factors) will provide important insight that can be applied to other regions and will assist local water managers.

  18. Can benthic community structure be used to predict the process of bioturbation in real ecosystems?

    NASA Astrophysics Data System (ADS)

    Queirós, Ana M.; Stephens, Nicholas; Cook, Richard; Ravaglioli, Chiara; Nunes, Joana; Dashfield, Sarah; Harris, Carolyn; Tilstone, Gavin H.; Fishwick, James; Braeckman, Ulrike; Somerfield, Paul J.; Widdicombe, Stephen

    2015-09-01

    Disentangling the roles of environmental change and natural environmental variability on biologically mediated ecosystem processes is paramount to predict future marine ecosystem functioning. Bioturbation, the biogenic mixing of sediments, has a regulating role in marine biogeochemical processes. However, our understanding of bioturbation as a community level process and of its environmental drivers is still limited by loose use of terminology, and a lack of consensus about what bioturbation is. To help resolve these challenges, this empirical study investigated the links between four different attributes of bioturbation (bioturbation depth, activity and distance, and biodiffusive transport); the ability of an index of bioturbation (BPc) to predict each of them; and their relation to seasonality, in a shallow coastal system - the Western Channel Observatory, UK. Bioturbation distance depended on changes in benthic community structure, while the other three attributes were more directly influenced by seasonality in food availability. In parallel, BPc successfully predicted bioturbation distance but not the other attributes of bioturbation. This study therefore highlights that community bioturbation results from this combination of processes responding to environmental variability at different time-scales. However, community level measurements of bioturbation across environmental variability are still scarce, and BPc is calculated using commonly available data on benthic community structure and the functional classification of invertebrates. Therefore, BPc could be used to support the growth of landscape scale bioturbation research, but future uses of the index need to consider which bioturbation attributes the index actually predicts. As BPc predicts bioturbation distance, estimated here using a random-walk model applicable to community settings, studies using either of the metrics should be directly comparable and contribute to a more integrated future for

  19. Impacts of introduced Rangifer on ecosystem processes of maritime tundra on subarctic islands

    USGS Publications Warehouse

    Ricca, Mark; Miles, A. Keith; Van Vuren, Dirk H.; Eviner, Valerie T.

    2016-01-01

    Introductions of mammalian herbivores to remote islands without predators provide a natural experiment to ask how temporal and spatial variation in herbivory intensity alter feedbacks between plant and soil processes. We investigated ecosystem effects resulting from introductions of Rangifer tarandus (hereafter “Rangifer”) to native mammalian predator- and herbivore-free islands in the Aleutian archipelago of Alaska. We hypothesized that the maritime tundra of these islands would experience either: (1) accelerated ecosystem processes mediated by positive feedbacks between increased graminoid production and rapid nitrogen cycling; or (2) decelerated processes mediated by herbivory that stimulated shrub domination and lowered soil fertility. We measured summer plant and soil properties across three islands representing a chronosequence of elapsed time post-Rangifer introduction (Atka: ~100 yr; Adak: ~50; Kagalaska: ~0), with distinct stages of irruptive population dynamics of Rangifer nested within each island (Atka: irruption, K-overshoot, decline, K-re-equilibration; Adak: irruption, K-overshoot; Kagalaska: initial introduction). We also measured Rangifer spatial use within islands (indexed by pellet group counts) to determine how ecosystem processes responded to spatial variation in herbivory. Vegetation community response to herbivory varied with temporal and spatial scale. When comparing temporal effects using the island chronosequence, increased time since herbivore introduction led to more graminoids and fewer dwarf-shrubs, lichens, and mosses. Slow-growingCladonia lichens that are highly preferred winter forage were decimated on both long-termRangifer-occupied islands. In addition, linear relations between more concentrated Rangifer spatial use and reductions in graminoid and forb biomass within islands added spatial heterogeneity to long-term patterns identified by the chronosequence. These results support, in part, the hypothesis that

  20. Insecticide use in hybrid onion seed production affects pre- and postpollination processes.

    PubMed

    Gillespie, Sandra; Long, Rachael; Seitz, Nicola; Williams, Neal

    2014-02-01

    Research on threats to pollination service in agro-ecosystems has focused primarily on the negative impacts of land use change and agricultural practices such as insecticide use on pollinator populations. Insecticide use could also affect the pollination process, through nonlethal impacts on pollinator attraction and postpollination processes such as pollen viability or pollen tube growth. Hybrid onion seed (Allium cepa L., Alliaceae) is an important pollinator-dependent crop that has suffered yield declines in California, concurrent with increased insecticide use. Field studies suggest that insecticide use reduces pollination service in this system. We conducted a field experiment manipulating insecticide use to examine the impacts of insecticides on 1) pollinator attraction, 2) pollen/stigma interactions, and 3) seed set and seed quality. Select insecticides had negative impacts on pollinator attraction and pollen/stigma interactions, with certain products dramatically reducing pollen germination and pollen tube growth. Decreased pollen germination was not associated with reduced seed set; however, reduced pollinator attraction was associated with lower seed set and seed quality, for one of the two female lines examined. Our results highlight the importance of pesticide effects on the pollination process. Overuse may lead to yield reductions through impacts on pollinator behavior and postpollination processes. Overall, in hybrid onion seed production, moderation in insecticide use is advised when controlling onion thrips, Thrips tabaci, on commercial fields. PMID:24665681

  1. Processes of community development and responses of ecosystems to climate change

    SciTech Connect

    Redente, E.F.

    1989-05-26

    Our studies focus on attempting to understand the role of decomposer-primary producer linkages in successional dynamics. We are testing a series of hypotheses that relate changes in plant species composition during succession to changes in activity and structure of the soil microfloral and faunal community, dynamics of soil organic matter, and availability of soil nutrients. As these successional patterns are identified, they are being applied to understanding specific processes and mechanics involved in ecosystem development during recovery from moderate and severe disturbances. These findings are then being used in conjunction with simulation models to assess potential effects of climate change on ecosystems. Our research involves field studies in northwestern Colorado and southeastern Washington, laboratory studies, and simulation modeling. Ongoing projects include studies of response patterns of primary producer and soil microbial communities to nutrient additions (N, P, and sucrose), the function of mycorrhizal fungi in plant community development, and the dynamics of litter decomposition under semiarid conditions. New studies are being implemented to investigate the significance of nutrient transfers from VAM fungi to plants and plant-root exudate interactions, and to relate this to understanding their roles in succession.

  2. RELATIONSHIPS BETWEEN CULTURABLE SOIL MICROBIAL POPULATIONS AND GROSS NITROGEN TRANSFORMATION PROCESSES IN A CLAY LOAM SOIL ACROSS ECOSYSTEMS

    EPA Science Inventory

    The size and quality of soil organic matter (SOM) pool can vary between ecosystems and can affect many soil properties. The objective of this study was to examine the relationship between gross N transformation rates and microbial populations and to investigate the role that SOM...

  3. Interactions between geomorphology and ecosystem processes in travertine streams: Implications for decommissioning a dam on Fossil Creek, Arizona

    NASA Astrophysics Data System (ADS)

    Marks, Jane C.; Parnell, Roderic; Carter, Cody; Dinger, Eric C.; Haden, G. Allen

    2006-07-01

    Travertine deposits of calcium carbonate can dominate channel geomorphology in streams where travertine deposition creates a distinct morphology characterized by travertine terraces, steep waterfalls, and large pools. Algae and microorganisms can facilitate travertine deposition, but how travertine affects material and energy flow in stream ecosystems is less well understood. Nearly a century of flow diversion for hydropower production has decimated the natural travertine formations in Fossil Creek, Arizona. The dam will be decommissioned in 2005. Returning carbonate-rich spring water to the natural stream channel should promote travertine deposition. How will the recovery of travertine affect the ecology of the creek? To address this question, we compared primary production, decomposition, and the abundance and diversity of invertebrates and fish in travertine and riffle/run reaches of Fossil Creek, Arizona. We found that travertine supports higher primary productivity, faster rates of leaf litter decomposition, and higher species richness of the native invertebrate assemblage. Observations from snorkeling in the stream indicate that fish density is also higher in the travertine reach. We postulate that restoring travertine to Fossil Creek will increase stream productivity, rates of litter processing, and energy flow up the food web. Higher aquatic productivity could fundamentally shift the nature of the stream from a sink to a source of energy for the surrounding terrestrial landscape.

  4. Soil and sediments micromorphology: reconstruction of palaeoenvironments, anthropogenic processes, or more recent human impact on ecosystems

    NASA Astrophysics Data System (ADS)

    Gérard, Martine; Trombino, Luca; Stoops, Georges

    2014-05-01

    Soils and sediments registered the environmental changes in time and space, but also display components inherited from human activities, both in archaeological and in modern times. Micromorphological investigations carried out on undisturbed samples of soil and sediments by microscopic and ultramicroscopic techniques, correlated with mineralogy, geochemistry or biology, allow us to interpret the processes behind the formation of regoliths, sediments and anthropogenic deposits, from which a relative chronology, specific environmental conditions and/or extent of human impact may be deduced. The traditional optical microscopy observations, carried on the thin section groundmass and pedofeatures, provide clues on the different processes behind soils and sediments genesis (weathering, supergene, low T hydrothermal, anthropogenic) and their impact on ecosystems or on palaeoenvironments. In more recent times, the improvements in electron microscope imaging technology permit to make detailed observations up to the nanoscale, opening a new domain of observations to micromorphologists, both as regard of the micromass and of the thinner pedofeatures. Moreover, the optimisation of the microgeochemical mapping techniques, with spatially resolved chemical, isotopic or mineralogical analyses, is another powerful tool to gain insight in chemical migration fronts: the limit of the original rock fabric disappearance may be bypassed. In order to illustrate micromorphological researches in natural and man-influenced ecosystems, and to combine researches at different scales, several optical and electronic images of soils and sediments groundmass, associated to their microgeochemical characteristics will be presented, with selected examples taken from the climatic record of paleosols, the impact of hydrothermal alteration on saprolites, the neo-formation of minerals related to weathering process evolution, the protosoil formation in natural and human waste deposits, and the forensic

  5. Dust and canopy effects on snowpack melt and ecosystem processes in a subalpine forest

    NASA Astrophysics Data System (ADS)

    Maurer, G. E.; Bowling, D. R.

    2013-12-01

    Dust deposition lowers the albedo of mountain snowpacks and can significantly impact the rate of spring snowpack melt. Recent research has shown that aeolian dust deposition may significantly advance the timing of snowmelt and spring runoff in the hydrologic basins of the western U.S. These studies have focused on alpine and subalpine snowpacks with little to no overstory vegetation cover. We conducted a manipulative experiment to assess the impacts of dust deposition on snowpack melt and ecosystem processes in a subalpine conifer forest. From mid-March to the snow all gone date in 2010-2012, we scattered dust in forested plots at weekly to bi-weekly frequency. This roughly doubled the ambient dust loading at the site. In control and dust-addition treatments we measured the springtime decline in snow water equivalent, continuous soil temperature and moisture, and litter mass loss (decomposition) and soil respiration below the snowpack and during the warm season. Xylem water potential in conifers was also measured during the warm season. We found that the effect of dust deposition on the melt rate was dependent on the openness of the canopy within our forest, as were differences in the timing and magnitude of soil moisture changes. Ecosystem processes were similar in dust-addition and control plots and were responsive to soil temperature and moisture variations below the snowpack and during the warm season. From this we conclude that the effect of aeolian dust deposition on snowpack energy balance, and associated ecohydrological processes, varies with canopy structure in subalpine forests.

  6. How processing digital elevation models can affect simulated water budgets

    USGS Publications Warehouse

    Kuniansky, E.L.; Lowery, M.A.; Campbell, B.G.

    2009-01-01

    For regional models, the shallow water table surface is often used as a source/sink boundary condition, as model grid scale precludes simulation of the water table aquifer. This approach is appropriate when the water table surface is relatively stationary. Since water table surface maps are not readily available, the elevation of the water table used in model cells is estimated via a two-step process. First, a regression equation is developed using existing land and water table elevations from wells in the area. This equation is then used to predict the water table surface for each model cell using land surface elevation available from digital elevation models (DEM). Two methods of processing DEM for estimating the land surface for each cell are commonly used (value nearest the cell centroid or mean value in the cell). This article demonstrates how these two methods of DEM processing can affect the simulated water budget. For the example presented, approximately 20% more total flow through the aquifer system is simulated if the centroid value rather than the mean value is used. This is due to the one-third greater average ground water gradients associated with the centroid value than the mean value. The results will vary depending on the particular model area topography and cell size. The use of the mean DEM value in each model cell will result in a more conservative water budget and is more appropriate because the model cell water table value should be representative of the entire cell area, not the centroid of the model cell.

  7. Similar Local and Landscape Processes Affect Both a Common and a Rare Newt Species

    PubMed Central

    Denoël, Mathieu; Perez, Amélie; Cornet, Yves; Ficetola, Gentile Francesco

    2013-01-01

    Although rare species are often the focus of conservation measures, more common species may experience similar decline and suffer from the same threatening processes. We tested this hypothesis by examining, through an information-theoretic approach, the importance of ecological processes at multiple scales in the great crested newt Triturus cristatus, regionally endangered and protected in Europe, and the more common smooth newt, Lissotriton vulgaris. Both species were similarly affected by the same processes, i.e. suitability of aquatic and terrestrial components of their habitat at different scales, connectivity among breeding sites, and the presence of introduced fish. T. cristatus depended more on water depth and aquatic vegetation than L. vulgaris. The results show that environmental pressures threaten both common and rare species, and therefore the more widespread species should not be neglected in conservation programs. Because environmental trends are leading to a deterioration of aquatic and terrestrial habitat features required by newt populations, populations of the common species may follow the fate of the rarest species. This could have substantial conservation implications because of the numerical importance of common species in ecosystems and because commonness could be a transient state moving towards rarity. On the other hand, in agreement with the umbrella species concept, targeting conservation efforts on the most demanding species would also protect part of the populations of the most common species. PMID:23658765

  8. Mapping ecological processes and ecosystem services for prioritizing restoration efforts in a semi-arid Mediterranean river basin.

    PubMed

    Trabucchi, Mattia; O'Farrell, Patrick J; Notivol, Eduardo; Comín, Francisco A

    2014-06-01

    Semi-arid Mediterranean regions are highly susceptible to desertification processes which can reduce the benefits that people obtain from healthy ecosystems and thus threaten human wellbeing. The European Union Biodiversity Strategy to 2020 recognizes the need to incorporate ecosystem services into land-use management, conservation, and restoration actions. The inclusion of ecosystem services into restoration actions and plans is an emerging area of research, and there are few documented approaches and guidelines on how to undertake such an exercise. This paper responds to this need, and we demonstrate an approach for identifying both key ecosystem services provisioning areas and the spatial relationship between ecological processes and services. A degraded semi-arid Mediterranean river basin in north east Spain was used as a case study area. We show that the quantification and mapping of services are the first step required for both optimizing and targeting of specific local areas for restoration. Additionally, we provide guidelines for restoration planning at a watershed scale; establishing priorities for improving the delivery of ecosystem services at this scale; and prioritizing the sub-watersheds for restoration based on their potential for delivering a combination of key ecosystem services for the entire basin.

  9. Mapping Ecological Processes and Ecosystem Services for Prioritizing Restoration Efforts in a Semi-arid Mediterranean River Basin

    NASA Astrophysics Data System (ADS)

    Trabucchi, Mattia; O'Farrell, Patrick J.; Notivol, Eduardo; Comín, Francisco A.

    2014-06-01

    Semi-arid Mediterranean regions are highly susceptible to desertification processes which can reduce the benefits that people obtain from healthy ecosystems and thus threaten human wellbeing. The European Union Biodiversity Strategy to 2020 recognizes the need to incorporate ecosystem services into land-use management, conservation, and restoration actions. The inclusion of ecosystem services into restoration actions and plans is an emerging area of research, and there are few documented approaches and guidelines on how to undertake such an exercise. This paper responds to this need, and we demonstrate an approach for identifying both key ecosystem services provisioning areas and the spatial relationship between ecological processes and services. A degraded semi-arid Mediterranean river basin in north east Spain was used as a case study area. We show that the quantification and mapping of services are the first step required for both optimizing and targeting of specific local areas for restoration. Additionally, we provide guidelines for restoration planning at a watershed scale; establishing priorities for improving the delivery of ecosystem services at this scale; and prioritizing the sub-watersheds for restoration based on their potential for delivering a combination of key ecosystem services for the entire basin.

  10. Contrasting effects of hemiparasites on ecosystem processes: can positive litter effects offset the negative effects of parasitism?

    PubMed Central

    Suding, Katharine N.

    2010-01-01

    Hemiparasites are known to influence community structure and ecosystem functioning, but the underlying mechanisms are not well studied. Variation in the impacts of hemiparasites on diversity and production could be due to the difference in the relative strength of two interacting pathways: direct negative effects of parasitism and positive effects on N availability via litter. Strong effects of parasitism should result in substantial changes in diversity and declines in productivity. Conversely, strong litter effects should result in minor changes in diversity and increased productivity. We conducted field-based surveys to determine the association of Castillejaoccidentalis with diversity and productivity in the alpine tundra. To examine litter effects, we compared the decomposition of Castilleja litter with litter of four other abundant plant species, and examined the decomposition of those four species when mixed with Castilleja. Castilleja was associated with minor changes in diversity but almost a twofold increase in productivity and greater foliar N in co-occurring species. Our decomposition trials suggest litter effects are due to both the rapid N loss of Castilleja litter and the effects of mixing Castilleja litter with co-occurring species. Castilleja produces litter that accelerates decomposition in the alpine tundra, which could accelerate the slow N cycle and boost productivity. We speculate that these positive effects of litter outweigh the effects of parasitism in nutrient-poor systems with long-lived hemiparasites. Determining the relative importance of parasitism and litter effects of this functional group is crucial to understand the strong but variable roles hemiparasites play in affecting community structure and ecosystem processes. PMID:20658151

  11. Interactive effects of winter weather variation and nitrogen deposition on alpine moist meadow ecosystem processes in the Rocky Mountains

    NASA Astrophysics Data System (ADS)

    Churchill, A. C.

    2015-12-01

    Alpine climate change in the Rocky Mountains has been linked to changes in precipitation patterns between summer and winter periods, and in total amounts of accumulation over the year. Annual variation in alpine snowpack can have important effects on concentrations and amounts of nitrogen (N) deposition entering the alpine from the atmosphere, as between one third to one half of N deposition occurs in association with precipitation, and high elevations primarily receive precipitation in the form of winter snow. Variation in snowpack further affects the amount and timing of water available to vegetation during the growing season, which can have large implications for alpine ecosystem responses in association with N deposition. To examine the potential interactive effects of variation in winter weather and N deposition, we established five sites along an ambient gradient of N deposition in the Rocky Mountains and collected measurements of N cycling between 2012 and 2014. This time frame included a year with low snow pack (2012), a year with average snow pack (2013), and a year with high snow pack (2014) among sites in the study, and allowed for us to examine candidate dynamic climatic drivers that may create variation in ecosystem processes associated with N. We found that soil water nitrate concentrations following snow melt were highly different for 4 sites along the N deposition gradient between 2013 and 2014. Growing season resin extractable N, however, was unaffected by inter-annual changes in winter precipitation. One possible explanation for no change in resin N may be associated with high inter-annual variation in plant community composition. There were significant differences in the species composition between 2012 and 2013, as well as shifts in the concentrations of N found in dominant plant species tissue. Our results suggest that plants will be important controls on biogeochemical responses of alpine moist meadows under variation in winter precipitation.

  12. Tropical forest carbon balance in a warmer world: a critical review spanning microbial- to ecosystem-scale processes.

    PubMed

    Wood, Tana E; Cavaleri, Molly A; Reed, Sasha C

    2012-11-01

    Tropical forests play a major role in regulating global carbon (C) fluxes and stocks, and even small changes to C cycling in this productive biome could dramatically affect atmospheric carbon dioxide (CO(2) ) concentrations. Temperature is expected to increase over all land surfaces in the future, yet we have a surprisingly poor understanding of how tropical forests will respond to this significant climatic change. Here we present a contemporary synthesis of the existing data and what they suggest about how tropical forests will respond to increasing temperatures. Our goals were to: (i) determine whether there is enough evidence to support the conclusion that increased temperature will affect tropical forest C balance; (ii) if there is sufficient evidence, determine what direction this effect will take; and, (iii) establish what steps should to be taken to resolve the uncertainties surrounding tropical forest responses to increasing temperatures. We approach these questions from a mass-balance perspective and therefore focus primarily on the effects of temperature on inputs and outputs of C, spanning microbial- to ecosystem-scale responses. We found that, while there is the strong potential for temperature to affect processes related to C cycling and storage in tropical forests, a notable lack of data combined with the physical, biological and chemical diversity of the forests themselves make it difficult to resolve this issue with certainty. We suggest a variety of experimental approaches that could help elucidate how tropical forests will respond to warming, including large-scale in situ manipulation experiments, longer term field experiments, the incorporation of a range of scales in the investigation of warming effects (both spatial and temporal), as well as the inclusion of a diversity of tropical forest sites. Finally, we highlight areas of tropical forest research where notably few data are available, including temperature effects on: nutrient cycling

  13. Tropical forest carbon balance in a warmer world: a critical review spanning microbial- to ecosystem-scale processes

    USGS Publications Warehouse

    Wood, Tana E.; Cavaleri, Molly A.; Reed, Sasha C.

    2012-01-01

    Tropical forests play a major role in regulating global carbon (C) fluxes and stocks, and even small changes to C cycling in this productive biome could dramatically affect atmospheric carbon dioxide (CO2) concentrations. Temperature is expected to increase over all land surfaces in the future, yet we have a surprisingly poor understanding of how tropical forests will respond to this significant climatic change. Here we present a contemporary synthesis of the existing data and what they suggest about how tropical forests will respond to increasing temperatures. Our goals were to: (i) determine whether there is enough evidence to support the conclusion that increased temperature will affect tropical forest C balance; (ii) if there is sufficient evidence, determine what direction this effect will take; and, (iii) establish what steps should to be taken to resolve the uncertainties surrounding tropical forest responses to increasing temperatures. We approach these questions from a mass-balance perspective and therefore focus primarily on the effects of temperature on inputs and outputs of C, spanning microbial- to ecosystem-scale responses. We found that, while there is the strong potential for temperature to affect processes related to C cycling and storage in tropical forests, a notable lack of data combined with the physical, biological and chemical diversity of the forests themselves make it difficult to resolve this issue with certainty. We suggest a variety of experimental approaches that could help elucidate how tropical forests will respond to warming, including large-scale in situ manipulation experiments, longer term field experiments, the incorporation of a range of scales in the investigation of warming effects (both spatial and temporal), as well as the inclusion of a diversity of tropical forest sites. Finally, we highlight areas of tropical forest research where notably few data are available, including temperature effects on: nutrient cycling

  14. Emotional Language Processing: How Mood Affects Integration Processes during Discourse Comprehension

    ERIC Educational Resources Information Center

    Egidi, Giovanna; Nusbaum, Howard C.

    2012-01-01

    This research tests whether mood affects semantic processing during discourse comprehension by facilitating integration of information congruent with moods' valence. Participants in happy, sad, or neutral moods listened to stories with positive or negative endings during EEG recording. N400 peak amplitudes showed mood congruence for happy and sad…

  15. Processes Affecting Nitrogen Speciation in a Karst Aquifer

    NASA Astrophysics Data System (ADS)

    Mahler, B. J.; Musgrove, M.; Wong, C. I.

    2011-12-01

    Like many karst aquifers, the Barton Springs segment of the Edwards aquifer, in central Texas, is in an area undergoing rapid growth in population, and there is concern as to how increased amounts of wastewater might affect groundwater quality. We measured concentrations and estimated loads of nitrogen (N) species in recharge to and discharge from the Barton Springs segment of the Edwards aquifer, central Texas, to evaluate processes affecting the transport and fate of N species in groundwater. Water samples were collected during 17 months (November 2008-March 2010) from five streams that contribute about 85% of recharge to the aquifer segment and from Barton Springs, the principal point of discharge from the segment. The sampling period spanned a range of climatic conditions from exceptional drought to above-normal rainfall. Samples were analyzed for N species (organic N + ammonia, ammonia, nitrate + nitrite, nitrite); loads of organic N and nitrate were estimated with LOADEST, a regression-based model that uses a time series of streamflow and measured constituent concentrations to estimate constituent loads. Concentrations of organic nitrogen and dissolved oxygen were higher and concentrations of nitrate were lower in surface water than in spring discharge, consistent with conversion of organic nitrogen to nitrate and associated consumption of dissolved oxygen in the aquifer. During the period of the study, the estimated load of organic N in recharge from streams (average daily load [adl] of 39 kg/d) was about 10 times that in Barton Springs discharge (adl of 9.4 kg/d), whereas the estimated load of nitrate in recharge from streams (adl of 123 kg/d) was slightly less than that in Barton Springs discharge (adl of 148 kg/d). The total average N load in recharge from streams and discharge from Barton Springs was not significantly different (adl of 162 and 157 kg/d, respectively), indicating that surface-water recharge can account for all of the N in Barton Springs

  16. Fish biodiversity sampling in stream ecosystems: a process for evaluating the appropriate types and amount of gear

    USGS Publications Warehouse

    Smith, Joseph M.; Wells, Sarah P.; Mather, Martha E.; Muth, Robert M.

    2014-01-01

    When researchers and managers initiate sampling on a new stream or river system, they do not know how effective each gear type is and whether their sampling effort is adequate. Although the types and amount of gear may be different for other studies, systems, and research questions, the five-step process described here for making sampling decisions and evaluating sampling efficiency can be applied widely to any system to restore, manage, and conserve aquatic ecosystems. It is believed that incorporating this gear-evaluation process into a wide variety of studies and ecosystems will increase rigour within and across aquatic biodiversity studies.

  17. Ozone deposition in a mixed forest ecosystem - temporal variation and removal processes

    NASA Astrophysics Data System (ADS)

    Pokorska, Olga; Gruening, Carsten; Goded, Ignacio

    2016-04-01

    Forests are a major sink for tropospheric ozone, however the fate of ozone within the forest canopy is still not well understood. In this study we will present results of 3 years ozone flux measurements at eddy covariance flux tower in Ispra (Northern Italy) over mixed forest ecosystem. The main tree species in this ecosystem are Quercus robur (80%), Alnus glutinosa (10%), Populus alba (5%) and Carpinus betulus (3%). The measurements were carried out continuously from January 2013 till December 2015. Flux measurements at the canopy level with the eddy covariance technique were complemented with measurements of meteorological parameters and measurements of VOCs (Volatile Organic Compounds) using PTR-MS (Proton Transfer Reaction - Mass Spectrometry) during an intensive observation period. Continuous measurements produced a big dataset which allowed us to investigate the controls on ozone fluxes and to do multiyear comparisons. Patterns of ozone concentration, ozone fluxes and ozone deposition velocity over forest canopy will be presented in relation to physiological activity of the trees and time of the year. Current research is mainly aimed at better understanding of the contribution of destruction processes within the canopy. Therefore, the collected data were used to calculate the partitioning of total ozone fluxes between stomatal and non-stomatal sinks. We found that the stomatal uptake contributed less that non-stomatal uptake to the total ozone flux during the growing seasons. In particular, non-stomatal ozone removal by reactions with isoprene and other VOCs will be discussed. We will present contribution and change of individual ozone deposition sinks over the years in response to environmental parameters.

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

    PubMed

    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.

  19. Effects Of Fungal-Mineral Interactions On Chemical Weathering And Denudation Processes - Observations From Experimental Ecosystems

    NASA Astrophysics Data System (ADS)

    Balogh, Z.; Keller, C.; Dickinson, J.

    2003-12-01

    A mesoscale (`sandbox') lysimeter experiment was performed at Hubbard Brook Experimental Forest, New Hampshire, to study plant-growth influences on chemical weathering and chemical denudation. Weathering was estimated by mass balance for 5 and 15-year intervals, and denudation was monitored as the product of drainage flow and concentration for 20 years in large (7.5x7.5x1.5m) fully lined sandboxes a.) planted with red pine (Pinus resinosa Ait.), and b.) kept free of vascular vegetation. Mass-balance equations included base cations (Ca, Mg, and K) in precipitation inputs and drainage outputs, and changes of base cation contents in biomass and soil. Scanning Electron Microscopy (SEM) and Environmental-SEM studies of the coarse sandbox soils were used for detection of mycorrhizal fungal association with roots, fungal development and attachment features on mineral grain surfaces. In the non-vascular system chemical weathering and denudation fluxes did not change significantly during the monitored period, but denudation fluxes were 1.3-1.4 times higher than weathering fluxes. In the vascular ecosystem the chemical weathering flux was 3 and 1.8 times greater than the denudation flux over 5 and 15 years, respectively, but both rates decreased over time. In our experiment the pines retarded denudation and accelerated weathering relative to the nonvascular system, thereby increasing available nutrient pools. The SEM and ESEM studies indicated more weathering features (etch pits, cracks, wholes, channels, and secondary minerals) in the mineral surfaces of the vascular system associated with the mycorrhizal fungal hyphae. Profiles of base-cation concentrations in soil water suggest that hyphal-mineral surface attachment might also insulate cation uptake from bulk soil water and hydrologic loss. The sandbox study offers insight into short-term effects of ecosystems on global biogeochemical processes.

  20. Sources and Processes Affecting Particulate Matter Pollution over North China

    NASA Astrophysics Data System (ADS)

    Zhang, L.; Shao, J.; Lu, X.; Zhao, Y.; Gong, S.; Henze, D. K.

    2015-12-01

    Severe fine particulate matter (PM2.5) pollution over North China has received broad attention worldwide in recent years. Better understanding the sources and processes controlling pollution over this region is of great importance with urgent implications for air quality policy. We will present a four-dimensional variational (4D-Var) data assimilation system using the GEOS-Chem chemical transport model and its adjoint model at 0.25° × 0.3125° horizontal resolution, and apply it to analyze the factors affecting PM2.5 concentrations over North China. Hourly surface observations of PM2.5 and sulfur dioxide (SO2) from the China National Environmental Monitoring Center (CNEMC) can be assimilated into the model to evaluate and constrain aerosol (primary and precursors) emissions. Application of the data assimilation system to the APEC period (the Asia-Pacific Economic Cooperation summit; 5-11 November 2014) shows that 46% of the PM2.5 pollution reduction during APEC ("The APEC Blue") can be attributed to meteorology conditions and the rest 54% to emission reductions due to strict emission controls. Ammonia emissions are shown to significantly contribute to PM2.5 over North China in the fall. By converting sulfuric acid and nitric acid to longer-lived ammonium sulfate and ammonium nitrate aerosols, ammonia plays an important role in promoting their regional transport influences. We will also discuss the pathways and mechanisms of external long-range transport influences to the PM2.5 pollution over North China.

  1. Addiction Motivation Reformulated: An Affective Processing Model of Negative Reinforcement

    ERIC Educational Resources Information Center

    Baker, Timothy B.; Piper, Megan E.; McCarthy, Danielle E.; Majeskie, Matthew R.; Fiore, Michael C.

    2004-01-01

    This article offers a reformulation of the negative reinforcement model of drug addiction and proposes that the escape and avoidance of negative affect is the prepotent motive for addictive drug use. The authors posit that negative affect is the motivational core of the withdrawal syndrome and argue that, through repeated cycles of drug use and…

  2. Processes Affecting Carbon Fluxes of Grassland Ecosystems Under Elevated CO{sub 2}

    SciTech Connect

    Owensby, C.E.; Ham, J.M.; Rice, C.W.; Knapp, A.K.

    1998-03-14

    Final report of a project which exposed native tallgrass prairie to twice-ambient atmospheric CO{sub 2}. Improved water use efficiency increased biomass production and increased soil organic matter. Twice ambient CO{sub 2} decreased canopy evapotranspiration by 22%, but, maintained an increased net carbon sequestration.

  3. Phylogenetic beta diversity in bacterial assemblages across ecosystems: deterministic versus stochastic processes

    SciTech Connect

    Wang, Jianjun; Shen, Jianhaua; Wu, Yucheng; Tu, Chen; Soininen , Janne; Stegen, James C.; He, Jizheng; Liu, Xingqi; Zhang, Lu; Zhang, Enlou

    2013-02-28

    Increasing evidence emerged for non-random spatial distributions for microbes, but the underlying processes resulting in microbial assemblage variation among and within Earth’s ecosystems is still lacking. For instance, some studies showed that the deterministic processes by habitat specialization are important, while other studies hold that bacterial communities are assembled by neutral forces. Here we examine the relative importance of deterministic and stochastic processes for bacterial communities from subsurface environments, as well as stream biofilm, lake water, lake sediment and soil using pyrosequencing of 16S rRNA gene. We show that there is a general pattern in phylogenetic signal in species niches across recent evolutionary time for all studied habitats, enabling us to infer the influences of community assembly processes from patterns of phylogenetic turnover in community composition. The phylogenetic dissimilarities among habitat types were significantly higher than within them, and the communities were clustered according to their original habitat types. For communities within habitat types, the highest phylogenetic turnover rate through space was observed in subsurface environments, followed by stream biofilm on mountainsides, whereas the sediment assemblages across regional scales showed the lowest turnover rate. Quantifying phylogenetic turnover as the deviation from a null expectation suggested that measured environmental variables imposed strong selection on bacterial communities for nearly all sample groups, and for three sample groups, that spatial distance reflects unmeasured environmental variables that impose selection, as opposed to spatial isolation. Such characterization of spatial and environmental variables proved essential for proper interpretation of partial mantel results based on observed beta diversity metrics. In summary, our results clearly indicate a dominant role of deterministic processes on bacterial assemblages and

  4. Modelling the impact of soil erosion on element transfer processes in agro-ecosystems

    NASA Astrophysics Data System (ADS)

    Shi, Pu; Della Peruta, Raniero; Keller, Armin; Schulin, Rainer

    2014-05-01

    Soil erosion is the main cause for loss of soil fertility worldwide. It can lead to degradation of soil structure, pollution of water bodies, decrease in crop productivity, and excessive accumulation of nutrients and trace elements in locations where eroded sediments are re-deposited. Research into the element transfer in fields and landscapes associated with erosion has hitherto focused on the assessment of element mobilization and nutrient export into aquatic ecosystems. Less is known about the role of erosion in element redistribution within terrestrial environments. Hence, we are developing a GIS-linked model that describes and visualizes areal patterns of particle-bound element transfer processes at the field to catchment scale, adapting and combining existing process-based mechanistic models of soil erosion, soil hydrology, sediment transport, crop growth, soil nutrient turnover and soil pollutant dynamics. The model will be tested in a case study of selected catchment in the framework of the Swiss National Research Program 'Sustainable Use of Soil as a Resource' (NRP 68). The goal is to create a tool that can be used to aid monitoring nutrient and pollutant fluxes associated with erosion in agricultural landscapes, in particular to identify hot spots of excessive pollutant accumulation related to the deposition of eroded sediments on agricultural land for different scenarios of land use and climate change, and to support the evaluation of land management strategies aiming to control them.

  5. Amazon Column CO2 & CO Observations to Elucidate Tropical Ecosystem Processes

    NASA Astrophysics Data System (ADS)

    Dubey, M. K.; Parker, H. A.; Myers, K.; Wennberg, P. O.; Wunch, D.; Allen, N.; Kawa, S. R.; Keppel-Aleks, G.; Miller, J. B.; O'Dell, C.; Feist, D. G.; Osterman, G. B.

    2015-12-01

    The Amazon basin stores 150-200 PgC, exchanges 18 PgC with the atmosphere every year and has taken up 0.42-0.65 PgC/y over the past two decades. Despite its global significance, the response of the tropical carbon cycle to climate variability and change is ill constrained. The complex interplay of radiation, water and ecosystem phenology remains unresolved in tropical ecosystem models. We use high frequency regional scale TCCON observations of column CO2, CO and CH4 near Manaus, Brazil that began in October 2014 to understand the aforementioned interplay of processes. We observe a robust mean daily column CO2 uptake of about 1.8 ppm (5 ppm to 0.5 ppm) over 8 hours and evaluate how it changes as we transition to the dry season. Back-trajectory calculations show that the daily CO2 uptake footprint is terrestrial and influenced by the heterogeneity of the Amazon rain forests. The column CO falls from above 120 ppb to below 80 ppb as we transition from the biomass burning to wet seasons. The daily mean column CO2 rises by 3 ppm from October through June. Removal of biomass burning and secular CO2 increase during this period implies an increase of 3.5 ppm that is attributed to tropical biospheric processes (respiration and photosynthesis). This is consistent with ground-based and eddy flux observations that indicate that tree phenology (e.g. leaf flushing) plays an important role in the tropical carbon cycle in regions that are not water limited and is not considered in current models. We compare our observations with output from carbon cycle models with assimilated meteorology (e.g. NASA's CASA/GFED) and find they under predict the daily drawdown of CO2 by a factor of 2.5. We plan to perform comparisons with other models (e.g. CLM) and also determine the net carbon flux from the Amazon basin by combining back-trajectory analysis and observations of column CO2 made at Ascension Island that is upwind of our site.

  6. Gaining insight into river ecosystem processes from a large-scale flow experiment

    NASA Astrophysics Data System (ADS)

    Harrison, L.; Pike, A.; Boughton, D. A.

    2015-12-01

    In rivers throughout the world, anthropogenic impacts related to large dams have altered or eliminated the habitat necessary for many aquatic organisms. Flow experiments, both planned and unplanned, provide unique opportunities to evaluate the extent to which alternative dam operations can provide downstream ecological benefits. Here we use an unanticipated, reservoir release on the Santa Ynez River in southern California to investigate how a large flood influenced river ecosystem processes. We directly measured the flood-induced, topographic changes over 80 km of the river and floodplain using two high-resolution field and remote sensing data sets that bracketed the flood event. DEM-differencing of the pre- and post-flood topography was used to calculate shifts in the active channel planform and the net volumetric fluxes in gravel storage along the channel and floodplain. LiDAR and image-based habitat mapping was conducted to quantify the proportion of different habitat units before and after the flood. Large-scale geomorphic changes were observed as a result of the flood, including lateral migration of the river channel, gravel bar formation and the development of off-channel chute habitat. Spatial patterns of gravel storage changed with distance from the dam, with the upper 20 km experiencing a net sediment deficit and the lower 60 km undergoing net deposition. The longitudinal trends in gravel transport and storage reflect differences in the channel gradient, valley confinement and density of floodplain vegetation. We found that the flood nearly doubled the extent of pool habitat, primarily by converting runs to pools and by incising new pools adjacent to valley walls and terraces. The increase in the number of pools was predicted to have positive impacts on steelhead habitat, by providing a broader range of water depths and micro-habitats utilized by different age classes. Results from this study highlight the value of using flow pulses as opportunities to

  7. Benthic processes affecting contaminant transport in Upper Klamath Lake, Oregon

    USGS Publications Warehouse

    Kuwabara, James S.; Topping, Brent R.; Carter, James L.; Carlson, Rick A; Parchaso, Francis; Fend, Steven V.; Stauffer-Olsen, Natalie; Manning, Andrew J.; Land, Jennie M.

    2016-09-30

    Executive SummaryMultiple sampling trips during calendar years 2013 through 2015 were coordinated to provide measurements of interdependent benthic processes that potentially affect contaminant transport in Upper Klamath Lake (UKL), Oregon. The measurements were motivated by recognition that such internal processes (for example, solute benthic flux, bioturbation and solute efflux by benthic invertebrates, and physical groundwater-surface water interactions) were not integrated into existing management models for UKL. Up until 2013, all of the benthic-flux studies generally had been limited spatially to a number of sites in the northern part of UKL and limited temporally to 2–3 samplings per year. All of the benthic invertebrate studies also had been limited to the northern part of the lake; however, intensive temporal (weekly) studies had previously been completed independent of benthic-flux studies. Therefore, knowledge of both the spatial and temporal variability in benthic flux and benthic invertebrate distributions for the entire lake was lacking. To address these limitations, we completed a lakewide spatial study during 2013 and a coordinated temporal study with weekly sampling of benthic flux and benthic invertebrates during 2014. Field design of the spatially focused study in 2013 involved 21 sites sampled three times as the summer cyanobacterial bloom developed (that is, May 23, June 13, and July 3, 2013). Results of the 27-week, temporally focused study of one site in 2014 were summarized and partitioned into three periods (referred to herein as pre-bloom, bloom and post-bloom periods), each period involving 9 weeks of profiler deployments, water column and benthic sampling. Partitioning of the pre-bloom, bloom, and post-bloom periods were based on water-column chlorophyll concentrations and involved the following date intervals, respectively: April 15 through June 10, June 17 through August 13, and August 20 through October 16, 2014. To examine

  8. Balancing Broad Ideas with Context: An Evaluation of Student Accuracy in Describing Ecosystem Processes after a System-Level Intervention

    ERIC Educational Resources Information Center

    Jordan, Rebecca C.; Brooks, Wesley R.; Hmelo-Silver, Cindy; Eberbach, Catherine; Sinha, Suparna

    2014-01-01

    Promoting student understanding of ecosystem processes is critical to biological education. Yet, teaching complex life systems can be difficult because systems are dynamic and often behave in a non-linear manner. In this paper, we discuss assessment results from a middle school classroom intervention in which a conceptual representation framework…

  9. User's Guide for Subroutine PLOT3D. Physical Processes in Terrestrial and Aquatic Ecosystems, Computer Programs and Graphics Capabilities.

    ERIC Educational Resources Information Center

    Gales, Larry

    This module is part of a series 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. PLOT3D is a subroutine package which generates a variety of three dimensional hidden…

  10. Programmer's Guide for Subroutine PRNT3D. Physical Processes in Terrestrial and Aquatic Ecosystems, Computer Programs and Graphics Capabilities.

    ERIC Educational Resources Information Center

    Gales, Larry

    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. PRNT3D is a subroutine package which generates a variety of printed plot displays. The displays…

  11. User's Guide for Subroutine PRNT3D. Physical Processes in Terrestrial and Aquatic Ecosystems, Computer Programs and Graphics Capabilities.

    ERIC Educational Resources Information Center

    Gales, Larry

    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. PRNT3D is a subroutine package which generates a variety of printer plot displays. The displays…

  12. Programmer's Guide for Subroutine PLOT3D. Physical Processes in Terrestrial and Aquatic Ecosystems, Computer Programs and Graphics Capabilities.

    ERIC Educational Resources Information Center

    Gales, Larry

    This module is part of a series 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. PLOT3D is a subroutine package which generates a variety of three-dimensional hidden…

  13. Modeling of hydroecological feedbacks predicts distinct classes of landscape pattern, process, and restoration potential in shallow aquatic ecosystems

    NASA Astrophysics Data System (ADS)

    Larsen, Laurel G.; Harvey, Judson W.

    2011-03-01

    It is widely recognized that interactions between vegetation and flow cause the emergence of channel patterns that are distinct from the standard Schumm classification of river channels. Although landscape pattern is known to be linked to ecosystem services such as habitat provision, pollutant removal, and sustaining biodiversity, the mechanisms responsible for the development and stability of different landscape patterns in shallow, vegetated flows have remained poorly understood. Fortunately, recent advances have made possible large-scale models of flow through vegetated environments that can be run over a range of environmental variables and over timescales of millennia. We describe a new, quasi-3D cellular automata model that couples simulations of shallow-water flow, bed shear stresses, sediment transport, and vegetation dynamics in an efficient manner. That efficiency allowed us to apply the model widely in order to determine how different hydroecological feedbacks control landscape pattern and process in various types of wetlands and floodplains. Distinct classes of landscape pattern were uniquely associated with specific types of allogenic and autogenic drivers in wetland flows. Regular, anisotropically patterned wetlands were dominated by allogenic processes (i.e., processes driven by periodic high water levels and flow velocities that redistribute sediment), relative to autogenic processes (e.g., vegetation production, peat accretion, and gravitational erosion). These anistropically patterned wetlands are therefore particularly prone to hydrologic disturbance. Other classes of wetlands that emerged from simulated interactions included maze-patterned, amorphous, and topographically noisy marshes, open marsh with islands, banded string-pool sequences perpendicular to flow, parallel deep and narrow channels flanked by marsh, and ridge-and-slough patterned marsh oriented parallel to flow. Because vegetation both affects and responds to the balance between the

  14. Impact of photochemical processing of DOC on the bacterioplankton respiratory quotient in aquatic ecosystems

    NASA Astrophysics Data System (ADS)

    Allesson, Lina; Ström, Lena; Berggren, Martin

    2016-07-01

    Many studies assume a respiratory quotient (RQ = molar ratio of CO2 produced to O2 consumed) close to 1 when calculating bacterioplankton respiration. However, evidence suggests that RQ depends on the chemical composition of the respired substrate pool that may be altered by photochemical production of oxygen-rich substrates, resulting in elevated RQs. Here we conducted a novel study of the impact of photochemical processing of dissolved organic carbon (DOC) on RQ. We monitored the bacterial RQ in bioassays of both ultraviolet light irradiated and nonirradiated humic lake water, using optic gas-pressure sensors. In the experimentally irradiated samples the average RQ value was significantly higher (3.4-3.5 [±0.4 standard error (SE)]) than that in the dark controls (1.3 [±0.1 SE]). Our results show that the RQ is systematically higher than 1 when the bacterial metabolism in large part is based on photoproducts. By assuming an RQ of 1, bacterioplankton respiration in freshwater ecosystems may be greatly underestimated.

  15. Aquatic ecosystems in Central Colorado are influenced by mineral forming processes and historical mining

    USGS Publications Warehouse

    Schmidt, T.S.; Church, S.E.; Clements, W.H.; Mitchell, K.A.; Fey, D. L.; Wanty, R.B.; Verplanck, P.L.; San, Juan C.A.; Klein, T.L.; deWitt, E.H.; Rockwell, B.W.

    2009-01-01

    Stream water and sediment toxicity to aquatic insects were quantified from central Colorado catchments to distinguish the effect of geologic processes which result in high background metals concentrations from historical mining. Our sampling design targeted small catchments underlain by rocks of a single lithology, which allowed the development of biological and geochemical baselines without the complication of multiple rock types exposed in the catchment. By accounting for geologic sources of metals to the environment, we were able to distinguish between the environmental effects caused by mining and the weathering of different mineralized areas. Elevated metal concentrations in water and sediment were not restricted to mined catchments. Impairment of aquatic communities also occurred in unmined catchments influenced by hydrothermal alteration. Hydrothermal alteration style, deposit type, and mining were important determinants of water and sediment quality and aquatic community structure. Weathering of unmined porphyry Cu-Mo occurrences resulted in water (median toxic unit (TU) = 108) and sediment quality (TU = 1.9) that exceeded concentrations thought to be safe for aquatic ecosystems (TU = 1). Metalsensitive aquatic insects were virtually absent from streams draining catchments with porphyry Cu-Mo occurrences (1.1 individuals/0.1 m2 ). However, water and sediment quality (TU = 0.1, 0.5 water and sediment, respectively) and presence of metalsensitive aquatic insects (204 individuals/0.1 m2 ) for unmined polymetallic vein occurrences were indistinguishable from that for unmined and unaltered streams (TU = 0.1, 0.5 water and sediment, respectively; 201 individuals/0.1 m2 ). In catchments with mined quartz-sericite-pyrite altered polymetallic vein deposits, water (TU = 8.4) and sediment quality (TU = 3.1) were degraded and more toxic to aquatic insects (36 individuals/0.1 m2 ) than water (TU = 0.4) and sediment quality (TU = 1.7) from mined propylitically altered

  16. Genotypic variation in tomatoes affecting processing and antioxidant attributes.

    PubMed

    Siddiqui, Mohammed Wasim; Ayala-Zavala, J F; Dhua, R S

    2015-01-01

    Tomatoes are widely consumed either raw or after processing and can provide a significant proportion of the total antioxidants in the diet associated with beneficial health properties. Over the last two or three decades an increasing interest for processing and antioxidant attributes in tomatoes has arisen. The screening of processing attributes of tomatoes is subject of a large number of articles; however, special interest has been addressed to the biochemical composition. The postharvest and industrial processing of tomato in tomato-based products includes several steps. Processing and antioxidant characteristics of the raw fruit are important considering the processing steps and final product. To respond to consumer and industrial complaints, breeders should know the range of genetic variability available in tomato resources, including local genotypes, for improving the mentioned attributes. Characterization and conservation of traditional and modern varieties is a major goal for their preservation and utilization. The bioactive contents have an impact on the processed destines so their stability must be contemplated while selecting the tomato fruits for processing. The endeavor of this review was to examine comprehensively the variation in processing and antioxidant attributes among tomatoes. Role of tomato peel in terms of bioactive contents and information on high pigment (hp) tomato mutants are also touched to some extent. Probably, patterns of variation identified/discussed in this paper would give impetus for planning breeding strategies to develop and improve the new processing cultivars with good antioxidant status.

  17. Do microbial processes regulate the stability of a coral atoll's enclosed pelagic ecosystem?

    EPA Science Inventory

    Complex marine ecosystems contain multiple feedback cycles that can cause unexpected responses to perturbations. To better predict these responses, complicated models are increasingly being developed to enable the study of feedback cycles. However, the sparseness of ecological da...

  18. A probabilistic process model for pelagic marine ecosystems informed by Bayesian inverse analysis

    EPA Science Inventory

    Marine ecosystems are complex systems with multiple pathways that produce feedback cycles, which may lead to unanticipated effects. Models abstract this complexity and allow us to predict, understand, and hypothesize. In ecological models, however, the paucity of empirical data...

  19. THE EFFECTS OF ECOSYSTEM RESTORATION ON NITROGEN PROCESSING IN AN URBAN MID-ATLANTIC PIEDMONT STREAM

    EPA Science Inventory

    Elevated nitrate levels in streams and groundwater pose human and ecological threats. The US Environmental Protection Agency, US Geological Survey, Institute of Ecosystem Studies, and Baltimore County Dept. of Environmental Protection and Resource Management are collaborating on...

  20. How Word Frequency Affects Morphological Processing in Monolinguals and Bilinguals

    ERIC Educational Resources Information Center

    Lehtonen, Minna; Laine, Matti

    2003-01-01

    The present study investigated processing of morphologically complex words in three different frequency ranges in monolingual Finnish speakers and Finnish-Swedish bilinguals. By employing a visual lexical decision task, we found a differential pattern of results in monolinguals vs. bilinguals. Monolingual Finns seemed to process low frequency and…

  1. Factors Affecting Location Decisions of Food Processing Plants

    NASA Astrophysics Data System (ADS)

    Turhan, Sule; Canan Ozbag, Basak; Cetin, Bahattin

    The main aim of this study is to examine the determinants of location choices for food processing plants using the results of 59 personal surveys. The 61.3% of the food processing plants that were interviewed are small scale plants, 9.1% are large scale plants and 29.6% are medium scale plants. Sixteen of the firms process vegetables, 12 process poultry, 12 process dairy and 9 process seafood products. Business climate factors are divided into six categories (market, infrastructure, raw material, labor, personal and environmental) and 17 specific location factors are considered. The survey responses are analyzed by types of raw materials processed and by plant size. 43.7, 55.3 and 42.2% of the respondents cited categories of Market, Raw Material and Infrastructure respectively as important, while 44.3, 50.7 and 74.4% of the respondents cited, labor, personal and environmental regulation categories of as not important. Thus survey findings indicate that plant location choices are mainly driven by market, raw material and infra structural factors. Environmental factors such as environmental regulations and permissions are relatively insignificant.

  2. Drying process strongly affects probiotics viability and functionalities.

    PubMed

    Iaconelli, Cyril; Lemetais, Guillaume; Kechaou, Noura; Chain, Florian; Bermúdez-Humarán, Luis G; Langella, Philippe; Gervais, Patrick; Beney, Laurent

    2015-11-20

    Probiotic formulations are widely used and are proposed to have a variety of beneficial effects, depending on the probiotic strains present in the product. The impact of drying processes on the viability of probiotics is well documented. However, the impact of these processes on probiotics functionality remains unclear. In this work, we investigated variations in seven different bacterial markers after various desiccation processes. Markers were composed of four different viability evaluation (combining two growth abilities and two cytometric measurements) and in three in vitro functionalities: stimulation of IL-10 and IL-12 production by PBMCs (immunomodulation) and bacterial adhesion to hexadecane. We measured the impact of three drying processes (air-drying, freeze-drying and spray-drying), without the use of protective agents, on three types of probiotic bacteria: Bifidobacterium bifidum, Lactobacillus plantarum and Lactobacillus zeae. Our results show that the bacteria respond differently to the three different drying processes, in terms of viability and functionality. Drying methods produce important variations in bacterial immunomodulation and hydrophobicity, which are correlated. We also show that adherence can be stimulated (air-drying) or inhibited (spray-drying) by drying processes. Results of a multivariate analysis show no direct correlation between bacterial survival and functionality, but do show a correlation between probiotic responses to desiccation-rewetting and the process used to dry the bacteria.

  3. Non-equilbrium dynamics of ecosystem processes in a changing world

    NASA Astrophysics Data System (ADS)

    Reid, Joseph Pignatello

    The relatively mild and stable climate of the last 10,000 years betrays a history of environmental variability and rapid changes. Humans have recently accelerated global environmental change, ushering in the Anthropocene. Meeting accelerating demands for food, energy, and goods and services has accelerated species extinctions, shows of reactive nitrogen and phosphorus, and warming of the atmosphere. I address the over- arching question of how ecosystems will respond to changing and variable environments through several focused studies. Each study examines an ecosystem response to ex- pected environmental changes in the future. To address how the changing environment affects the sizes and turnover rates of slowly and quickly cycling soil carbon pools, I analyzed the responses of grassland soils to simulated species diversity loss, increased deposition of nitrogen and increased atmospheric CO2. I used a soil respiration experiment to fit models of soil carbon pool turnover to respired carbon dioxide. Species diversity, nitrogen deposition and atmospheric CO2 had no effect on the total soil carbon after 8 years of treatments. Although total soil carbon did not change, the rates of cycling in the fast and slow pools changed in response to elevated CO2 and diversity loss treatments. Nitrogen treatments increased the size of the slowly cycling carbon pool. Precipitation variability has increased around most of the world since the industrial revolution. I used plant mesocosms in a greenhouse experiment to manipulate rainfall variability and mycorrhizal associations. I hypothesized that 1) rewetting events re- sult in higher nitrogen uxes from dry soils than moist soils, 2) a repeated pattern of events caused by low-frequency simulated rainfall results in higher nitrogen uxes and 3) the better ability of ectomycorrhizal fungi relative to arbuscular mycorrhizal fungi to decompose and assimilate organic nitrogen reduces leaching losses of nitrogen caused by both rewetting

  4. Non-equilbrium dynamics of ecosystem processes in a changing world

    NASA Astrophysics Data System (ADS)

    Reid, Joseph Pignatello

    The relatively mild and stable climate of the last 10,000 years betrays a history of environmental variability and rapid changes. Humans have recently accelerated global environmental change, ushering in the Anthropocene. Meeting accelerating demands for food, energy, and goods and services has accelerated species extinctions, shows of reactive nitrogen and phosphorus, and warming of the atmosphere. I address the over- arching question of how ecosystems will respond to changing and variable environments through several focused studies. Each study examines an ecosystem response to ex- pected environmental changes in the future. To address how the changing environment affects the sizes and turnover rates of slowly and quickly cycling soil carbon pools, I analyzed the responses of grassland soils to simulated species diversity loss, increased deposition of nitrogen and increased atmospheric CO2. I used a soil respiration experiment to fit models of soil carbon pool turnover to respired carbon dioxide. Species diversity, nitrogen deposition and atmospheric CO2 had no effect on the total soil carbon after 8 years of treatments. Although total soil carbon did not change, the rates of cycling in the fast and slow pools changed in response to elevated CO2 and diversity loss treatments. Nitrogen treatments increased the size of the slowly cycling carbon pool. Precipitation variability has increased around most of the world since the industrial revolution. I used plant mesocosms in a greenhouse experiment to manipulate rainfall variability and mycorrhizal associations. I hypothesized that 1) rewetting events re- sult in higher nitrogen uxes from dry soils than moist soils, 2) a repeated pattern of events caused by low-frequency simulated rainfall results in higher nitrogen uxes and 3) the better ability of ectomycorrhizal fungi relative to arbuscular mycorrhizal fungi to decompose and assimilate organic nitrogen reduces leaching losses of nitrogen caused by both rewetting

  5. Benthic processes affecting contaminant transport in Upper Klamath Lake, Oregon

    USGS Publications Warehouse

    Kuwabara, James S.; Topping, Brent R.; Carter, James L.; Carlson, Rick A; Parchaso, Francis; Fend, Steven V.; Stauffer-Olsen, Natalie; Manning, Andrew J.; Land, Jennie M.

    2016-09-30

    Executive SummaryMultiple sampling trips during calendar years 2013 through 2015 were coordinated to provide measurements of interdependent benthic processes that potentially affect contaminant transport in Upper Klamath Lake (UKL), Oregon. The measurements were motivated by recognition that such internal processes (for example, solute benthic flux, bioturbation and solute efflux by benthic invertebrates, and physical groundwater-surface water interactions) were not integrated into existing management models for UKL. Up until 2013, all of the benthic-flux studies generally had been limited spatially to a number of sites in the northern part of UKL and limited temporally to 2–3 samplings per year. All of the benthic invertebrate studies also had been limited to the northern part of the lake; however, intensive temporal (weekly) studies had previously been completed independent of benthic-flux studies. Therefore, knowledge of both the spatial and temporal variability in benthic flux and benthic invertebrate distributions for the entire lake was lacking. To address these limitations, we completed a lakewide spatial study during 2013 and a coordinated temporal study with weekly sampling of benthic flux and benthic invertebrates during 2014. Field design of the spatially focused study in 2013 involved 21 sites sampled three times as the summer cyanobacterial bloom developed (that is, May 23, June 13, and July 3, 2013). Results of the 27-week, temporally focused study of one site in 2014 were summarized and partitioned into three periods (referred to herein as pre-bloom, bloom and post-bloom periods), each period involving 9 weeks of profiler deployments, water column and benthic sampling. Partitioning of the pre-bloom, bloom, and post-bloom periods were based on water-column chlorophyll concentrations and involved the following date intervals, respectively: April 15 through June 10, June 17 through August 13, and August 20 through October 16, 2014. To examine

  6. Process Formulations And Curing Conditions That Affect Saltstone Properties

    SciTech Connect

    Reigel, M. M.; Pickenheim, B. R.; Daniel, W. E.

    2012-09-28

    The first objective of this study was to analyze saltstone fresh properties to determine the feasibility of reducing the formulation water to premix (w/p) ratio while varying the amount of extra water and admixtures used during processing at the Saltstone Production Facility (SPF). The second part of this study was to provide information for understanding the impact of curing conditions (cure temperature, relative humidity (RH)) and processing formulation on the performance properties of cured saltstone.

  7. Studies of dynamical processes affecting the distribution of stratospheric ozone

    NASA Technical Reports Server (NTRS)

    Bowman, Kenneth P.

    1993-01-01

    The purpose of the research was to understand large-scale tracer transport processes in the stratosphere. Two approaches were taken. The first is analysis of tracer observations, especially satellite observations of ozone concentration and total column ozone. The second is numerical simulation of tracer transport processes. Topics researched include: quasi-biennial oscillation (QBO) and stratospheric ozone; mixing in the polar vortices; polar stratospheric clouds (PSC) properties from Antarctic lidar data; and statistical methods for numerical experiments.

  8. Technical Report: Investigation of Carbon Cycle Processes within a Managed Landscape: An Ecosystem Manipulation and Isotope Tracer Approach

    SciTech Connect

    Griffis, Timothy J; Baker, John M; Billmark, Kaycie

    2009-06-01

    The goal of this research is to provide a better scientific understanding of carbon cycle processes within an agricultural landscape characteristic of the Upper Midwest. This project recognizes the need to study processes at multiple spatial and temporal scales to reduce uncertainty in ecosystem and landscape-scale carbon budgets to provide a sound basis for shaping future policy related to carbon management. Specifically, this project has attempted to answer the following questions: 1. Would the use of cover crops result in a shift from carbon neutral to significant carbon gain in corn-soybean rotation ecosystems of the Upper Midwest? 2. Can stable carbon isotope analyses be used to partition ecosystem respiration into its autotrophic and heterotrophic components? 3. Can this partitioning be used to better understand the fate of crop residues to project changes in the soil carbon reservoir? 4. Are agricultural ecosystems of the Upper Midwest carbon neutral, sinks, or sources? Can the proposed measurement and modeling framework help address landscape-scale carbon budget uncertainties and help guide future carbon management policy?

  9. A multitrophic model to quantify the effects of marine viruses on microbial food webs and ecosystem processes.

    PubMed

    Weitz, Joshua S; Stock, Charles A; Wilhelm, Steven W; Bourouiba, Lydia; Coleman, Maureen L; Buchan, Alison; Follows, Michael J; Fuhrman, Jed A; Jover, Luis F; Lennon, Jay T; Middelboe, Mathias; Sonderegger, Derek L; Suttle, Curtis A; Taylor, Bradford P; Frede Thingstad, T; Wilson, William H; Eric Wommack, K

    2015-06-01

    Viral lysis of microbial hosts releases organic matter that can then be assimilated by nontargeted microorganisms. Quantitative estimates of virus-mediated recycling of carbon in marine waters, first established in the late 1990s, were originally extrapolated from marine host and virus densities, host carbon content and inferred viral lysis rates. Yet, these estimates did not explicitly incorporate the cascade of complex feedbacks associated with virus-mediated lysis. To evaluate the role of viruses in shaping community structure and ecosystem functioning, we extend dynamic multitrophic ecosystem models to include a virus component, specifically parameterized for processes taking place in the ocean euphotic zone. Crucially, we are able to solve this model analytically, facilitating evaluation of model behavior under many alternative parameterizations. Analyses reveal that the addition of a virus component promotes the emergence of complex communities. In addition, biomass partitioning of the emergent multitrophic community is consistent with well-established empirical norms in the surface oceans. At steady state, ecosystem fluxes can be probed to characterize the effects that viruses have when compared with putative marine surface ecosystems without viruses. The model suggests that ecosystems with viruses will have (1) increased organic matter recycling, (2) reduced transfer to higher trophic levels and (3) increased net primary productivity. These model findings support hypotheses that viruses can have significant stimulatory effects across whole-ecosystem scales. We suggest that existing efforts to predict carbon and nutrient cycling without considering virus effects are likely to miss essential features of marine food webs that regulate global biogeochemical cycles.

  10. Food-web constraints on biodiversity–ecosystem functioning relationships

    PubMed Central

    Thébault, Elisa; Loreau, Michel

    2003-01-01

    The consequences of biodiversity loss for ecosystem functioning and ecosystem services have aroused considerable interest during the past decade. Recent work has focused mainly on the impact of species diversity within single trophic levels, both experimentally and theoretically. Experiments have usually showed increased plant biomass and productivity with increasing plant diversity. Changes in biodiversity, however, may affect ecosystem processes through trophic interactions among species as well. An important current challenge is to understand how these trophic interactions affect the relationship between biodiversity and ecosystem functioning. Here we present a mechanistic model of an ecosystem with multiple trophic levels in which plants compete for a limiting soil nutrient. In contrast to previous studies that focused on single trophic levels, we show that plant biomass does not always increase with plant diversity and that changes in biodiversity can lead to complex if predictable changes in ecosystem processes. Our analysis demonstrates that food-web structure can profoundly influence ecosystem properties. PMID:14638942

  11. The Climate Space Concept: Analysis of the Steady State Heat Energy Budget of Animals. Physical Processes in Terrestrial and Aquatic Ecosystems, Transport Processes.

    ERIC Educational Resources Information Center

    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. Several modules in the thermodynamic series considered the application of the First Law to…

  12. Developing a Data Driven Process-Based Model for Remote Sensing of Ecosystem Production

    NASA Astrophysics Data System (ADS)

    Elmasri, B.; Rahman, A. F.

    2010-12-01

    Estimating ecosystem carbon fluxes at various spatial and temporal scales is essential for quantifying the global carbon cycle. Numerous models have been developed for this purpose using several environmental variables as well as vegetation indices derived from remotely sensed data. Here we present a data driven modeling approach for gross primary production (GPP) that is based on a process based model BIOME-BGC. The proposed model was run using available remote sensing data and it does not depend on look-up tables. Furthermore, this approach combines the merits of both empirical and process models, and empirical models were used to estimate certain input variables such as light use efficiency (LUE). This was achieved by using remotely sensed data to the mathematical equations that represent biophysical photosynthesis processes in the BIOME-BGC model. Moreover, a new spectral index for estimating maximum photosynthetic activity, maximum photosynthetic rate index (MPRI), is also developed and presented here. This new index is based on the ratio between the near infrared and the green bands (ρ858.5/ρ555). The model was tested and validated against MODIS GPP product and flux measurements from two eddy covariance flux towers located at Morgan Monroe State Forest (MMSF) in Indiana and Harvard Forest in Massachusetts. Satellite data acquired by the Advanced Microwave Scanning Radiometer (AMSR-E) and MODIS were used. The data driven model showed a strong correlation between the predicted and measured GPP at the two eddy covariance flux towers sites. This methodology produced better predictions of GPP than did the MODIS GPP product. Moreover, the proportion of error in the predicted GPP for MMSF and Harvard forest was dominated by unsystematic errors suggesting that the results are unbiased. The analysis indicated that maintenance respiration is one of the main factors that dominate the overall model outcome errors and improvement in maintenance respiration estimation

  13. Species assembly in model ecosystems, II: Results of the assembly process.

    PubMed

    Capitán, José A; Cuesta, José A; Bascompte, Jordi

    2011-01-21

    In the companion paper of this set (Capitán and Cuesta, 2010) we have developed a full analytical treatment of the model of species assembly introduced in Capitán et al. (2009). This model is based on the construction of an assembly graph containing all viable configurations of the community, and the definition of a Markov chain whose transitions are the transformations of communities by new species invasions. In the present paper we provide an exhaustive numerical analysis of the model, describing the average time to the recurrent state, the statistics of avalanches, and the dependence of the results on the amount of available resource. Our results are based on the fact that the Markov chain provides an asymptotic probability distribution for the recurrent states, which can be used to obtain averages of observables as well as the time variation of these magnitudes during succession, in an exact manner. Since the absorption times into the recurrent set are found to be comparable to the size of the system, the end state is quickly reached (in units of the invasion time). Thus, the final ecosystem can be regarded as a fluctuating complex system where species are continually replaced by newcomers without ever leaving the set of recurrent patterns. The assembly graph is dominated by pathways in which most invasions are accepted, triggering small extinction avalanches. Through the assembly process, communities become less resilient (e.g., have a higher return time to equilibrium) but become more robust in terms of resistance against new invasions.

  14. Do differences in food web structure between organic and conventional farms affect the ecosystem service of pest control?

    PubMed

    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.

  15. Personality interacts with implicit affect to predict performance in analytic versus holistic processing.

    PubMed

    Kazén, Miguel; Kuhl, Julius; Quirin, Markus

    2015-06-01

    Both theoretical approaches and empirical evidence suggest that negative affect fosters analytic processing, whereas positive affect fosters holistic processing, but these effects are inconsistent. We aim to show that (a) differences in affect regulation abilities ("action orientation") and (b) implicit more so than self-reported affect assessment need to be considered to advance our understanding of these processes. Forty participants were asked to verify whether a word was correctly or incorrectly spelled to measure analytic processing, as well as to intuitively assess whether sets of three words were coherent (remote associates task) to measure holistic processing. As expected, implicit but not explicit negative affect interacted with low action orientation ("state orientation") to predict higher d' performance in word spelling, whereas implicit but not explicit positive affect interacted with high action orientation to predict higher d' performance in coherence judgments for word triads. Results are interpreted according to personality systems interaction theory. These findings suggest that affect and affect changes should be measured explicitly and implicitly to investigate affect-cognition interactions. Moreover, they suggest that good affect regulators benefit from positive affect for holistic processing, whereas bad affect regulators benefit from negative affect for analytical processing. PMID:24725069

  16. Psychometric Characteristics of the EEAA (Scale of Affective Strategies in the Learning Process)

    ERIC Educational Resources Information Center

    Villardón-Gallego, Lourdes; Yániz, Concepción

    2014-01-01

    Introduction: Affective strategies for coping with affective states linked to the learning process may be oriented toward controlling emotions or toward controlling motivation. Both types affect performance, directly and indirectly. The objective of this research was to design an instrument for measuring the affective strategies used by university…

  17. Changing Ecosystem Service Values Following Technological Change

    NASA Astrophysics Data System (ADS)

    Honey-Rosés, Jordi; Schneider, Daniel W.; Brozović, Nicholas

    2014-06-01

    Research on ecosystem services has focused mostly on natural areas or remote places, with less attention given to urban ecosystem services and their relationship with technological change. However, recent work by urban ecologists and urban designers has more closely examined and appreciated the opportunities associated with integrating natural and built infrastructures. Nevertheless, a perception remains in the literature on ecosystem services that technology may easily and irreversibly substitute for services previously obtained from ecosystems, especially when the superiority of the engineered system motivated replacement in the first place. We emphasize that the expected tradeoff between natural and manufactured capital is false. Rather, as argued in other contexts, the adoption of new technologies is complementary to ecosystem management. The complementarity of ecosystem services and technology is illustrated with a case study in Barcelona, Spain where the installation of sophisticated water treatment technology increased the value of the ecosystem services found there. Interestingly, the complementarity between natural and built infrastructures may remain even for the very ecosystems that are affected by the technological change. This finding suggests that we can expect the value of ecosystem services to co-evolve with new technologies. Technological innovation can generate new opportunities to harness value from ecosystems, and the engineered structures found in cities may generate more reliance on ecosystem processes, not less.

  18. Can Process Portfolios Affect Students' Writing Self-Efficacy?

    ERIC Educational Resources Information Center

    Nicolaidou, Iolie

    2012-01-01

    Can process portfolios that support students in goal setting, reflection, self-evaluation and feedback have a positive impact on students' writing self-efficacy? This article presents the findings of a yearlong study conducted in three 4th grade elementary classes in Cyprus where paper-based and web-based portfolios were implemented to help…

  19. Factors Affecting the Processing of Epoxy Film Adhesives

    NASA Technical Reports Server (NTRS)

    Pike, R. A.

    1985-01-01

    The increasing awareness that adhesive performance is controlled not only by the condition of the adherend surface but also the condition or state of the adhesive and the process parameters used during fabrication is expected to result in improved reliability, as well as bond performance. The critical process variables which have been found to control adhesive bond formation and ultimate bond strength in 250F and 350F curing epoxy adhesives are described in terms of fabrication parameters and adhesive characteristics. These include the heat-up rate and cure temperature during processing and the adhesive moisture content and age condition (degree of advancement). The diagnostic methods used to delineate the effects of these process variables on adhesive performance are illustrated. These are dielectric, thermomechanical (TMA) and dynamic mechanical (DMA) analyses. Correlation of test results with measured mechanical tensile lap shear strengths of bonded joints is presented and the results briefly discussed in terms of the additives and hardeners used in the adhesive systems.

  20. Stimulus Characteristics Affect Humor Processing in Individuals with Asperger Syndrome

    ERIC Educational Resources Information Center

    Samson, Andrea C.; Hegenloh, Michael

    2010-01-01

    The present paper aims to investigate whether individuals with Asperger syndrome (AS) show global humor processing deficits or whether humor comprehension and appreciation depends on stimulus characteristics. Non-verbal visual puns, semantic and Theory of Mind cartoons were rated on comprehension, funniness and the punchlines were explained. AS…

  1. Distal Prosodic Context Affects Word Segmentation and Lexical Processing

    ERIC Educational Resources Information Center

    Dilley, Laura C.; McAuley, J. Devin

    2008-01-01

    Three experiments investigated the role of distal (i.e., nonlocal) prosody in word segmentation and lexical processing. In Experiment 1, prosodic characteristics of the initial five syllables of eight-syllable sequences were manipulated; the final portions of these sequences were lexically ambiguous (e.g., "note bookworm", "notebook worm"). Distal…

  2. The conservation of the Shahr-e-Zohak archaeological site (central Afghanistan): Geomorphological processes and ecosystem-based mitigation

    NASA Astrophysics Data System (ADS)

    Margottini, Claudio; Fidolini, Francesco; Iadanza, Carla; Trigila, Alessandro; Ubelmann, Yves

    2015-06-01

    The archaeological remains of Shahr-e Zohak are part of the Bamiyan valley, which has been recognized by UNESCO as World Heritage and is famous for hosting the main heritage of the Buddhist culture in Afghanistan. The site comprises the remains of the Zohak fortress, which is placed on a steep hill at the confluence of the Bamiyan and Kalu rivers. The fortress is protected by ramparts, built along the steep cliffs bounding the site, which are equipped with several watchtowers. The citadel is protected by three more orders of walls and is located on the topmost part of the hill. All the structures are made of mudbricks placed on top of stony foundations. Due to the prolonged exposure to weathering, the lack of conservation measures and the misuse during war periods, many constructions collapsed or are prone to collapse. A new topography (1 m contour lines) of the site was produced using drone-derived 3D photogrammetry combined with GPS data. Then a detailed geomorphological survey of the whole site was carried out in order to identify the main geomorphic processes acting on the land surface and structures. GIS analysis allowed defining the internal drainage system of the studied area. The site is affected by incised erosional phenomena on the eastern side, while the hilltop is mainly hit by diffuse erosion and soil mobilization during snowmelt. Monument deterioration is coupled with the lack of an adequate drainage system to collect runoff. Ramparts located on the steep hillslopes are severely affected by gully erosion and siphoning, which cause depressions infilled by eroded and weathered building material. The access path is locally eroded or buried by debris cones. The western margin of the plateau has been rapidly retreating due to collapses, while the citadel is in danger due to diffuse or gully erosional processes developed on all its sides. A mitigation strategy with low environmental impact (ecosystem-based approach) is proposed in order to adopt sustainable

  3. DayCent-Chem Simulations of Ecological and Biogeochemical Processes of Eight Mountain Ecosystems in the United States

    USGS Publications Warehouse

    Hartman, Melannie D.; Baron, Jill S.; Clow, David W.; Creed, Irena F.; Driscoll, Charles T.; Ewing, Holly A.; Haines, Bruce D.; Knoepp, Jennifer; Lajtha, Kate; Ojima, Dennis S.; Parton, William J.; Renfro, Jim; Robinson, R. Bruce; Van Miegroet, Helga; Weathers, Kathleen C.; Williams, Mark W.

    2009-01-01

    deposition as a result of dry and fog inputs. The uncertainties related to weathering reactions, deposition, soil cation exchange capacity, and groundwater contributions influenced how well the simulated acid neutralizing capacity (ANC) and pH estimates compared to observed values. Daily discharge was well represented by the model for most sites. The chapters of this report describe the parameterization for each site and summarize model results for ecosystem variables, stream discharge, and stream chemistry. This intersite comparison exercise provided insight about important and possibly not well understood processes.

  4. Critical processes affecting Cryptosporidium oocyst survival in the environment.

    PubMed

    King, B J; Monis, P T

    2007-03-01

    Cryptosporidium are parasitic protozoans that cause gastrointestinal disease and represent a significant risk to public health. Cryptosporidium oocysts are prevalent in surface waters as a result of human, livestock and native animal faecal contamination. The resistance of oocysts to the concentrations of chlorine and monochloramine used to disinfect potable water increases the risk of waterborne transmission via drinking water. In addition to being resistant to commonly used disinfectants, it is thought that oocysts can persist in the environment and be readily mobilized by precipitation events. This paper will review the critical processes involved in the inactivation or removal of oocysts in the terrestrial and aquatic environments and consider how these processes will respond in the context of climate change. PMID:17096874

  5. Brain responses during sentence reading: visual input affects central processes.

    PubMed

    Gunter, T C; Friederici, A D; Hahne, A

    1999-10-19

    The effect of visual contrast on sentence reading was investigated using event-related brain potentials (ERPs). Under the low contrast condition semantic integration as reflected in the N400 ERP component was delayed to some degree. The left anterior negativity (LAN) reflecting initial syntactic processes, in contrast, seemed to change its characteristics as a function of visual input. In the high contrast condition the LAN preceded the P200 component whereas in the low contrast condition it was present after this component. These ERP-data from word-by-word sentence reading together with prior results from sentence listening suggest that the physical characteristics of the input must fall within a certain optimal range to guarantee ERP-effects of fast initial syntactic processes.

  6. Biotic Processes Regulating the Carbon Balance of Desert Ecosystems - Final Report

    SciTech Connect

    Nowak, Robert S; Smith, Stanley D; Evans, Dave; Ogle, Kiona; Fenstermaker, Lynn

    2012-12-13

    Our results from the 10-year elevated atmospheric CO{sub 2} concentration study at the Nevada Desert FACE (Free-air CO{sub 2} Enrichment) Facility (NDFF) indicate that the Mojave Desert is a dynamic ecosystem with the capacity to respond quickly to environmental changes. The Mojave Desert ecosystem is accumulating carbon (C), and over the 10-year experiment, C accumulation was significantly greater under elevated [CO{sub 2}] than under ambient, despite great fluctuations in C inputs from year to year and even apparent reversals in which [CO{sub 2}] treatment had greater C accumulations.

  7. An Ecosystem Model for the Simulation of Physical and Biological Oceanic Processes-IDAPAK User's Guide and Applications

    NASA Technical Reports Server (NTRS)

    McClain, Charles R.; Arrigo, Kevin; Murtugudde, Ragu; Signorini, Sergio R.; Tai, King-Sheng

    1998-01-01

    This TM describes the development, testing, and application of a 4-component (phytoplankton, zooplankton, nitrate, and ammonium) ecosystem model capable of simulating oceanic biological processes. It also reports and documents an in-house software package (Interactive Data Analysis Package - IDAPAK) for interactive data analysis of geophysical fields, including those related to the forcing, verification, and analysis of the ecosystem model. Two regions were studied in the Pacific: the Warm Pool (WP) in the Equatorial Pacific (165 deg. E at the equator) and at Ocean Weather Station P (OWS P) in the Northeast Pacific (50 deg. N, 145 deg. W). The WP results clearly indicate that the upwelling at 100 meters correlates well with surface blooms. The upwelling events in late 1987 and 1990 produced dramatic increases in the surface layer values of all 4 ecosystem components, whereas the spring-summer deep mixing events, do not seem to incur a significant response in any of the ecosystem quantities. The OWS P results show that the monthly profiles of temperature, the annual cycles of solar irradiance, and 0- to 50-m integrated nitrate accurately reproduce observed values. Annual primary production is 190 gC/m(exp 2)/yr, which is consistent with recent observations but is much greater than earlier estimates.

  8. Wetlands serve as natural sources for improvement of stream ecosystem health in regions affected by acid deposition.

    PubMed

    Pound, Katrina L; Lawrence, Gregory B; Passy, Sophia I

    2013-09-01

    For over 40 years, acid deposition has been recognized as a serious international environmental problem, but efforts to restore acidified streams and biota have had limited success. The need to better understand the effects of different sources of acidity on streams has become more pressing with the recent increases in surface water organic acids, or 'brownification,' associated with climate change and decreased inorganic acid deposition. Here, we carried out a large scale multi-seasonal investigation in the Adirondacks, one of the most acid-impacted regions in the United States, to assess how acid stream producers respond to local and watershed influences and whether these influences can be used in acidification remediation. We explored the pathways of wetland control on aluminum chemistry and diatom taxonomic and functional composition. We demonstrate that streams with larger watershed wetlands have higher organic content, lower concentrations of acidic anions, and lower ratios of inorganic to organic monomeric aluminum, all beneficial for diatom biodiversity and guilds producing high biomass. Although brownification has been viewed as a form of pollution, our results indicate that it may be a stimulating force for biofilm producers with potentially positive consequences for higher trophic levels. Our research also reveals that the mechanism of watershed control of local stream diatom biodiversity through wetland export of organic matter is universal in running waters, operating not only in hard streams, as previously reported, but also in acid streams. Our findings that the negative impacts of acid deposition on Adirondack stream chemistry and biota can be mitigated by wetlands have important implications for biodiversity conservation and stream ecosystem management. Future acidification research should focus on the potential for wetlands to improve stream ecosystem health in acid-impacted regions and their direct use in stream restoration, for example, through

  9. Wetlands serve as natural sources for improvement of stream ecosystem health in regions affected by acid deposition

    USGS Publications Warehouse

    Pound, Katrina L; Lawrence, Gregory B.; Passy, Sophia I.

    2013-01-01

    For over 40 years, acid deposition has been recognized as a serious international environmental problem, but efforts to restore acidified streams and biota have had limited success. The need to better understand the effects of different sources of acidity on streams has become more pressing with the recent increases in surface water organic acids, or 'brownification' associated with climate change and decreased inorganic acid deposition. Here, we carried out a large scale multi-seasonal investigation in the Adirondacks, one of the most acid-impacted regions in the United States, to assess how acid stream producers respond to local and watershed influences and whether these influences can be used in acidification remediation. We explored the pathways of wetland control on aluminum chemistry and diatom taxonomic and functional composition. We demonstrate that streams with larger watershed wetlands have higher organic content, lower concentrations of acidic anions, and lower ratios of inorganic to organic monomeric aluminum, all beneficial for diatom biodiversity and guilds producing high biomass. Although brownification has been viewed as a form of pollution, our results indicate that it may be a stimulating force for biofilm producers with potentially positive consequences for higher trophic levels. Our research also reveals that the mechanism of watershed control of local stream diatom biodiversity through wetland export of organic matter is universal in running waters, operating not only in hard streams, as previously reported, but also in acid streams. Our findings that the negative impacts of acid deposition on Adirondack stream chemistry and biota can be mitigated by wetlands have important implications for biodiversity conservation and stream ecosystem management. Future acidification research should focus on the potential for wetlands to improve stream ecosystem health in acid-impacted regions and their direct use in stream restoration, for example, through

  10. Wetlands serve as natural sources for improvement of stream ecosystem health in regions affected by acid deposition.

    PubMed

    Pound, Katrina L; Lawrence, Gregory B; Passy, Sophia I

    2013-09-01

    For over 40 years, acid deposition has been recognized as a serious international environmental problem, but efforts to restore acidified streams and biota have had limited success. The need to better understand the effects of different sources of acidity on streams has become more pressing with the recent increases in surface water organic acids, or 'brownification,' associated with climate change and decreased inorganic acid deposition. Here, we carried out a large scale multi-seasonal investigation in the Adirondacks, one of the most acid-impacted regions in the United States, to assess how acid stream producers respond to local and watershed influences and whether these influences can be used in acidification remediation. We explored the pathways of wetland control on aluminum chemistry and diatom taxonomic and functional composition. We demonstrate that streams with larger watershed wetlands have higher organic content, lower concentrations of acidic anions, and lower ratios of inorganic to organic monomeric aluminum, all beneficial for diatom biodiversity and guilds producing high biomass. Although brownification has been viewed as a form of pollution, our results indicate that it may be a stimulating force for biofilm producers with potentially positive consequences for higher trophic levels. Our research also reveals that the mechanism of watershed control of local stream diatom biodiversity through wetland export of organic matter is universal in running waters, operating not only in hard streams, as previously reported, but also in acid streams. Our findings that the negative impacts of acid deposition on Adirondack stream chemistry and biota can be mitigated by wetlands have important implications for biodiversity conservation and stream ecosystem management. Future acidification research should focus on the potential for wetlands to improve stream ecosystem health in acid-impacted regions and their direct use in stream restoration, for example, through

  11. Modeling compensatory responses of ecosystem-scale water fluxes in forests affected by pine and spruce beetle mortality

    NASA Astrophysics Data System (ADS)

    Millar, D.; Ewers, B. E.; Peckham, S. D.; Mackay, D. S.; Frank, J. M.; Massman, W. J.; Reed, D. E.

    2015-12-01

    Mountain pine beetle (Dendroctonus ponderosae) and spruce beetle (Dendroctonus rufipennis) epidemics have led to extensive mortality in lodgepole pine (Pinus contorta) and Engelmann spruce (Picea engelmannii) forests in the Rocky Mountains of the western US. In both of these tree species, mortality results from hydraulic failure within the xylem, due to blue stain fungal infection associated with beetle attack. However, the impacts of these disturbances on ecosystem-scale water fluxes can be complex, owing to their variable and transient nature. In this work, xylem scaling factors that reduced whole-tree conductance were initially incorporated into a forest ecohydrological model (TREES) to simulate the impact of beetle mortality on evapotranspiration (ET) in both pine and spruce forests. For both forests, simulated ET was compared to observed ET fluxes recorded using eddy covariance techniques. Using xylem scaling factors, the model overestimated the impact of beetle mortality, and observed ET fluxes were approximately two-fold higher than model predictions in both forests. The discrepancy between simulated and observed ET following the onset of beetle mortality may be the result of spatial and temporal heterogeneity of plant communities within the foot prints of the eddy covariance towers. Since simulated ET fluxes following beetle mortality in both forests only accounted for approximately 50% of those observed in the field, it is possible that newly established understory vegetation in recently killed tree stands may play a role in stabilizing ecosystem ET fluxes. Here, we further investigate the unaccounted for ET fluxes in the model by breaking it down into multiple cohorts that represent live trees, dying trees, and understory vegetation that establishes following tree mortality.

  12. Understanding processes affecting mineral deposits in humid environments

    USGS Publications Warehouse

    Seal, Robert R., II; Ayuso, Robert A.

    2011-01-01

    Recent interdisciplinary studies by the U.S. Geological Survey have resulted in substantial progress toward understanding the influence that climate and hydrology have on the geochemical signatures of mineral deposits and the resulting mine wastes in the eastern United States. Specific areas of focus include the release, transport, and fate of acid, metals, and associated elements from inactive mines in temperate coastal areas and of metals from unmined mineral deposits in tropical to subtropical areas; the influence of climate, geology, and hydrology on remediation options for abandoned mines; and the application of radiogenic isotopes to uniquely apportion source contributions that distinguish natural from mining sources and extent of metal transport. The environmental effects of abandoned mines and unmined mineral deposits result from a complex interaction of a variety of chemical and physical factors. These include the geology of the mineral deposit, the hydrologic setting of the mineral deposit and associated mine wastes, the chemistry of waters interacting with the deposit and associated waste material, the engineering of a mine as it relates to the reactivity of mine wastes, and climate, which affects such factors as temperature and the amounts of precipitation and evapotranspiration; these factors, in turn, influence the environmental behavior of mineral deposits. The role of climate is becoming increasingly important in environmental investigations of mineral deposits because of the growing concerns about climate change.

  13. Diesel oil volatilization processes affected by selected porous media.

    PubMed

    Ma, Yanfei; Zheng, Xilai; Anderson, S H; Lu, Jie; Feng, Xuedong

    2014-03-01

    Volatilization plays an important role in attenuating petroleum products in contaminated soils. The objective of this study was to evaluate the influence of wind speed, vessel diameter and mean grain size of porous media on diesel oil volatilization. Experiments were conducted to investigate the volatilization behavior of diesel oil from porous media by weighing contaminated samples pre- and post-volatilization. Three selected field porous media materials were evaluated: Silty Clay Loam, Fine Sand, and Coarse Sand along with six individual sand fractions of the Coarse Sand. Results indicate that increasing wind speed accelerates the diesel oil volatilization process, especially for wind speeds below 2.10ms(-1). The low-carbon components of diesel oil volatilize more rapidly, with the effects of wind speed more pronounced on C10 to C15 volatilization than on C16 and higher. The volatilization rate coefficient of diesel oil increases with decreasing mean grain size of porous media, and with increasing vessel diameter. A power function expressed the relationship with mean grain size. All processes (wind speed, vessel diameter, and mean grain size) were included in an equation which explained over 92% of the measured diesel oil volatilization rate coefficient variations for the experiments. Diesel oil volatilization appears to be boundary-layer regulated to some extent.

  14. Does Signal Degradation Affect Top-Down Processing of Speech?

    PubMed

    Wagner, Anita; Pals, Carina; de Blecourt, Charlotte M; Sarampalis, Anastasios; Başkent, Deniz

    2016-01-01

    Speech perception is formed based on both the acoustic signal and listeners' knowledge of the world and semantic context. Access to semantic information can facilitate interpretation of degraded speech, such as speech in background noise or the speech signal transmitted via cochlear implants (CIs). This paper focuses on the latter, and investigates the time course of understanding words, and how sentential context reduces listeners' dependency on the acoustic signal for natural and degraded speech via an acoustic CI simulation.In an eye-tracking experiment we combined recordings of listeners' gaze fixations with pupillometry, to capture effects of semantic information on both the time course and effort of speech processing. Normal-hearing listeners were presented with sentences with or without a semantically constraining verb (e.g., crawl) preceding the target (baby), and their ocular responses were recorded to four pictures, including the target, a phonological (bay) competitor and a semantic (worm) and an unrelated distractor.The results show that in natural speech, listeners' gazes reflect their uptake of acoustic information, and integration of preceding semantic context. Degradation of the signal leads to a later disambiguation of phonologically similar words, and to a delay in integration of semantic information. Complementary to this, the pupil dilation data show that early semantic integration reduces the effort in disambiguating phonologically similar words. Processing degraded speech comes with increased effort due to the impoverished nature of the signal. Delayed integration of semantic information further constrains listeners' ability to compensate for inaudible signals. PMID:27080670

  15. The HIV Tat protein affects processing of ribosomal RNA precursor

    PubMed Central

    Ponti, Donatella; Troiano, Maria; Bellenchi, Gian Carlo; Battaglia, Piero A; Gigliani, Franca

    2008-01-01

    Background Inside the cell, the HIV Tat protein is mainly found in the nucleus and nucleolus. The nucleolus, the site of ribosome biogenesis, is a highly organized, non-membrane-bound sub-compartment where proteins with a high affinity for nucleolar components are found. While it is well known that Tat accumulates in the nucleolus via a specific nucleolar targeting sequence, its function in this compartment it still unknown. Results To clarify the significance of the Tat nucleolar localization, we induced the expression of the protein during oogenesis in Drosophila melanogaster strain transgenic for HIV-tat gene. Here we show that Tat localizes in the nucleoli of Drosophila oocyte nurse cells, where it specifically co-localizes with fibrillarin. Tat expression is accompanied by a significant decrease of cytoplasmic ribosomes, which is apparently related to an impairment of ribosomal rRNA precursor processing. Such an event is accounted for by the interaction of Tat with fibrillarin and U3 snoRNA, which are both required for pre-rRNA maturation. Conclusion Our data contribute to understanding the function of Tat in the nucleolus, where ribosomal RNA synthesis and cell cycle control take place. The impairment of nucleolar pre-rRNA maturation through the interaction of Tat with fibrillarin-U3snoRNA complex suggests a process by which the virus modulates host response, thus contributing to apoptosis and protein shut-off in HIV-uninfected cells. PMID:18559082

  16. Integrating ecosystems measurements from multiple eddy-covariance sites to a simple model of ecosystem process - Are there possibilities for a uniform model calibration?

    NASA Astrophysics Data System (ADS)

    Minunno, Francesco; Peltoniemi, Mikko; Launiainen, Samuli; Mäkelä, Annikki

    2014-05-01

    Biogeochemical models quantify the material and energy flux exchanges between biosphere, atmosphere and soil, however there is still considerable uncertainty underpinning model structure and parametrization. The increasing availability of data from of multiple sources provides useful information for model calibration and validation at different space and time scales. We calibrated a simplified ecosystem process model PRELES to data from multiple sites. In this work we had the following objective: to compare a multi-site calibration and site-specific calibrations, in order to test if PRELES is a model of general applicability, and to test how well one parameterization can predict ecosystem fluxes. Model calibration and evaluation were carried out by the means of the Bayesian method; Bayesian calibration (BC) and Bayesian model comparison (BMC) were used to quantify the uncertainty in model parameters and model structure. Evapotranspiration (ET) and gross primary production (GPP) measurements collected in 9 sites of Finland and Sweden were used in the study; half dataset was used for model calibrations and half for the comparative analyses. 10 BCs were performed; the model was independently calibrated for each of the nine sites (site-specific calibrations) and a multi-site calibration was achieved using the data from all the sites in one BC. Then 9 BMCs were carried out, one for each site, using output from the multi-site and the site-specific versions of PRELES. Similar estimates were obtained for the parameters at which model outputs are most sensitive. Not surprisingly, the joint posterior distribution achieved through the multi-site calibration was characterized by lower uncertainty, because more data were involved in the calibration process. No significant differences were encountered in the prediction of the multi-site and site-specific versions of PRELES, and after BMC, we concluded that the model can be reliably used at regional scale to simulate carbon and

  17. Secondary Students' Dynamic Modeling Processes: Analyzing, Reasoning About, Synthesizing, and Testing Models of Stream Ecosystems.

    ERIC Educational Resources Information Center

    Stratford, Steven J.; Krajeik, Joseph; Soloway, Elliot

    This paper presents the results of a study of the cognitive strategies in which ninth-grade science students engaged as they used a learner-centered dynamic modeling tool (called Model-It) to make original models based upon stream ecosystem scenarios. The research questions were: (1) In what Cognitive Strategies for Modeling (analyzing, reasoning,…

  18. Ecosystem Research in EPA: Process Studies, Field Investigations, and Integrated Environmental Modeling

    EPA Science Inventory

    The Ecosystems Research Division (ERD) is located in Athens, GA, USA. The research goals of ERD is to assess and quantify pathways and transformations of contaminants in the environment and to determine how physical changes (e.g., development, mining roads, green infrastructure, ...

  19. Evaluating potential indicators of ecosystem processes across local gradients in a temperate grassland

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Science-based information is needed to identify indicators of ecosystem services that may then be used to monitor natural resources and quantify effects of management. Here our aim was to perform a local gradient study to elucidate correlative associations between vegetation and multiple soil prope...

  20. THE EFFECTS OF ECOSYSTEM RESTORATION ON NITROGEN PROCESSING IN AN URBAN MID-ATLANTIC PIEDMONT STREAM

    EPA Science Inventory

    Elevated nitrate levels in streams and groundwater pose human and ecological threats. The US EPA, USGS, Institute of Ecosystem Studies, and Baltimore County Dept. of Environmental Protection are collaborating on a multi-year study of the impacts of stream restoration on nitrogen...

  1. Acute physical exercise affected processing efficiency in an auditory attention task more than processing effectiveness.

    PubMed

    Dutke, Stephan; Jaitner, Thomas; Berse, Timo; Barenberg, Jonathan

    2014-02-01

    Research on effects of acute physical exercise on performance in a concurrent cognitive task has generated equivocal evidence. Processing efficiency theory predicts that concurrent physical exercise can increase resource requirements for sustaining cognitive performance even when the level of performance is unaffected. This hypothesis was tested in a dual-task experiment. Sixty young adults worked on a primary auditory attention task and a secondary interval production task while cycling on a bicycle ergometer. Physical load (cycling) and cognitive load of the primary task were manipulated. Neither physical nor cognitive load affected primary task performance, but both factors interacted on secondary task performance. Sustaining primary task performance under increased physical and/or cognitive load increased resource consumption as indicated by decreased secondary task performance. Results demonstrated that physical exercise effects on cognition might be underestimated when only single task performance is the focus.

  2. Iodine Affects Differentiation and Migration Process in Trophoblastic Cells.

    PubMed

    Olivo-Vidal, Zendy Evelyn; Rodríguez, Roció Coutiño; Arroyo-Helguera, Omar

    2016-02-01

    Iodine deficiency is associated with oxidative stress increase and preeclampsia during gestation, suggesting that iodine concentration plays an important role in the normal placenta physiology. The question raised is to analyze the effect of iodine deficiency on oxidative stress, viability, differentiation, and migration process and changes in the expression of differentiation and migration markers. Iodine deprivation was done using potassium perchlorate (KCLO4) to block sodium iodide symporter (NIS) transporter and 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid DIDS to inhibit pendrine (PEN) transport for 3-48 h. Then trophoblast cells were treated with low iodine doses of 5-500 μM and high iodine doses of 100-5000 μM. Oxidative stress, viability, and human chorionic gonadotropin (hGC) were measured by colorimetric methods. Migration throphoblast cells were evaluated by both wound healing and Boyden chamber assays. Changes in mRNA expression were analyzed by real-time RT-PCR. Iodine deprivation induces a significant increase of reactive oxygen species (ROS), viability, and migration process vs control cells. We found a significant overregulation in the mRNA's peroxisome proliferator-activated receptor (PPAR-gamma), Snail, and matrix metalloproteinase-9 (MMP-9) mRNA's in cells deprived of iodine, as well as a down glial cell missing-1 (GCM-1) regulation, hGC, pregnancy-associated plasma protein-A (PAPP-A), and E-cadherin mRNA expression. The expression of hypoxic induction factor alpha (HIFα) mRNA does not change with iodine deprivation. In cells deprived of iodine, supplementing low iodine doses (5-500 μM) does not induce any significant changes in viability. However, ROS and migration process were decreased, although we found an increased human chorionic gonadotropin (hCG) secretion as a differentiation marker. In addition, we found that PPAR-gamma, Snail, and MPP-9 mRNAs expression are downregulated with low iodine doses, in contrast with GCM-1, PAPP

  3. Incorporating Ecosystem Experiments and Observations into Process Models of Forest Carbon and Water Cycles: Challenges and Solutions

    NASA Astrophysics Data System (ADS)

    Ward, E. J.; Thomas, R. Q.; Sun, G.; McNulty, S. G.; Domec, J. C.; Noormets, A.; King, J. S.

    2015-12-01

    Numerous studies, both experimental and observational, have been conducted over the past two decades in an attempt to understand how water and carbon cycling in terrestrial ecosystems may respond to changes in climatic conditions. These studies have produced a wealth of detailed data on key processes driving these cycles. In parallel, sophisticated models of these processes have been formulated to answer a variety of questions relevant to natural resource management. Recent advances in data assimilation techniques offer exciting new possibilities to combine this wealth of ecosystem data with process models of ecosystem function to improve prediction and quantify associated uncertainty. Using forests of the southeastern United States as our focus, we will specify how fine-scale physiological (e.g. half-hourly sap flux) can be scaled up with quantified error for use in models of stand growth and hydrology. This approach represents an opportunity to leverage current and past research from experiments including throughfall displacement × fertilization (PINEMAP), irrigation × fertilization (SETRES), elevated CO­2­ (Duke and ORNL FACE) and a variety of observational studies in both conifer and hardwood forests throughout the region, using a common platform for data assimilation and prediction. As part of this discussion, we will address variation in dominant species, stand structure, site age, management practices, soils and climate that represent both challenges to the development of a common analytical approach and opportunities to address questions of interest to policy makers and natural resource managers.

  4. Silicification of Thermophilic Biofilms: Do Aquificales Affect the Mineralisation Process?

    NASA Astrophysics Data System (ADS)

    Konhauser, K.; Lalonde, S.; Aguiar, P.; Reysenbach, A.

    2003-12-01

    In geothermal environments, biomineralisation is an inevitable consequence of microbes growing in solute-rich waters. The process of silicification is of particular interest due to (1) apparent discrepancies between natural and laboratory silicification rates and (2) siliceous microfossils currently serve as the earliest physical evidence for life on Earth. Although mesophilic microbe-silica interactions have been studied in great detail, there is a paucity of information on the role that thermophiles play in the silicification process, i.e., does their metabolism in any way facilitate silicification and do their cellular remains fossilise? To help resolve some of these uncertainties, a thermophilic, biofilm-forming member of the Aquificales order, Sulfurihydrogenobium azorense, was grown in the presence of various concentrations of silica, ranging from undersaturated to those extremely supersaturated with respect to amorphous silica. Since the chemolithoautotrophic Aquificales use of a wide range and combination of electron donors and acceptors, the bacteria cultured were grown in the presence of H2 with O2, S and Fe(III) as terminal electron acceptors. This study focused on the rates of pH-induced silica polymerisation during a 48 hour interval, when the soluble silica phase was at its most reactive stage, and when the greatest amount of silica immobilisation was likely to occur. S. azorense was found to have no detectable effect on the polymerisation rate of silica under any condition tested, nor did it cause silica to precipitate in undersaturated conditions. In addition, transmission electron microscopy showed that although silica did indeed precipitate from solution, there was no obvious association between solid-phase silica and the cells walls. This suggests that under high silica levels there is such a strong chemical driving force for silica polymerisation, homogeneous nucleation, and ultimately silica precipitation that there is no obvious need for

  5. Quantitative evolution of volcanic surfaces affected by erosional processes

    NASA Astrophysics Data System (ADS)

    Lahitte, Pierre; Boillot-Airaksinen, Kim; Germa, Aurélie; Lavigne, Franck

    2016-04-01

    Variations through time of erosion dynamics, a key point to investigate correlation between climates and landform evolution, still remains poorly documented. One of the main issue in this type of study is the difficulty in determining for how long the erosion has operated. For this purpose, volcanic contexts are particularly suitable for defining the temporal dynamics governing erosion since the age of volcanic activity also constrains the age of emplacement of the surface today eroded, and thus the erosion duration. Furthermore, quantitative analysis of river profiles offers the opportunity to discriminate, among the wide variety of geological phenomena influencing erosion, their respective influence. Quantification of erosion processes and constrain of their signature on reliefs can be addressed by a morphometric approach of river profiles in volcanic environment through the analysis of digital topography (DEM). Break in slope zones, the so-called knickpoints, are usually related to a retreat of the point between the relict channel, upstream, and the adjusted channel, downstream. They are induced by either a lithological contrast, a change in the base level, uplift or eustatism, or a rejuvenation of the age of the volcanic surface. The stream long-profile and its watershed is also investigated by their concavity and hypsometric indexes to determine for how long the complexity and its heterogeneity along the valley incision remain visible. The present study focusses on the erosion of volcanoes in the Lesser Antilles, Reunion Island and Lombok Island (Indonesia). All located in tropical environments, these volcanoes offer a wide diversity of age (30 - 0 Ma) and lithology for investigating the respective influence of geological processes that have induced a large variety of shapes and volcanic history that we try to correlate to geometry of river profiles.

  6. Effects of landcover, water redistribution, and temperature on ecosystem processes in the South Plate Basin

    USGS Publications Warehouse

    Baron, J. S.; Hartman, M.D.; Kittel, T. G. F.; Band, L.E.; Ojima, D. S.; Lammers, R.B.

    1998-01-01

    Over one-third of the land area in the South Platte Basin of Colorado, Nebraska, and Wyoming, has been converted to croplands. Irrigated cropland now comprises 8% of the basin, while dry croplands make up 31%. We used the RHESSys model to compare the changes in plant productivity and vegetation-related hydrological processes that occurred as a result of either land cover alteration or directional temperature changes (−2°C, +4°C). Land cover change exerted more control over annual plant productivity and water fluxes for converted grasslands, while the effect of temperature changes on productivity and water fluxes was stronger in the mountain vegetation. Throughout the basin, land cover change increased the annual loss of water to the atmosphere by 114 mm via evaporation and transpiration, an increase of 37%. Both irrigated and nonirrigated grains became active earlier in the year than shortgrass steppe, leading to a seasonal shift in water losses to the atmosphere. Basin-wide photosynthesis increased by 80% due to grain production. In contrast, a 4°C warming scenario caused annual transpiration to increase by only 3% and annual evaporation to increase by 28%, for a total increase of 71 mm. Warming decreased basin-wide photosynthesis by 16%. There is a large elevational range from east to west in the South Platte Basin, which encompasses the western edge of the Great Plains and the eastern front of the Rocky Mountains. This elevational gain is accompanied by great changes in topographic complexity, vegetation type, and climate. Shortgrass steppe and crops found at elevations between 850 and 1800 m give way to coniferous forests and tundra between 1800 and 4000 m. Climate is increasingly dominated by winter snow precipitation with increasing elevation, and the timing of snowmelt influences tundra and forest ecosystem productivity, soil moisture, and downstream discharge. Mean annual precipitation of <500 mm on the plains below 1800 m is far less than potential

  7. Root dynamics in an artificially constructed regenerating longleaf pine ecosystem are affected by atmospheric CO(2) enrichment.

    PubMed

    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

  8. Early Social Experience Affects the Development of Eye Gaze Processing.

    PubMed

    Senju, Atsushi; Vernetti, Angélina; Ganea, Natasa; Hudry, Kristelle; Tucker, Leslie; Charman, Tony; Johnson, Mark H

    2015-12-01

    Eye gaze is a key channel of non-verbal communication in humans. Eye contact with others is present from birth, and eye gaze processing is crucial for social learning and adult-infant communication. However, little is known about the effect of selectively different experience of eye contact and gaze communication on early social and communicative development. To directly address this question, we assessed 14 sighted infants of blind parents (SIBPs) longitudinally at 6-10 and 12-16 months. Face scanning and gaze following were assessed using eye tracking. In addition, naturalistic observations were made when the infants were interacting with their blind parent and with an unfamiliar sighted adult. Established measures of emergent autistic-like behaviors and standardized tests of cognitive, motor, and linguistic development were also collected. These data were then compared with those obtained from a group of infants of sighted parents. Despite showing typical social skills development overall, infants of blind parents allocated less attention to adult eye movements and gaze direction, an effect that increased between 6-10 and 12-16 months of age. The results suggest that infants adjust their use of adults' eye gaze depending on gaze communication experience from early in life. The results highlight that human functional brain development shows selective experience-dependent plasticity adaptive to the individual's specific social environment.

  9. Nitrogen and phosphorus in the Upper Mississippi River: Transport, processing, and effects on the river ecosystem

    USGS Publications Warehouse

    Houser, J.N.; Richardson, W.B.

    2010-01-01

    Existing research on nutrients (nitrogen and phosphorus) in the Upper Mississippi River (UMR) can be organized into the following categories: (1) Long-term changes in nutrient concentrations and export, and their causes; (2) Nutrient cycling within the river; (3) Spatial and temporal patterns of river nutrient concentrations; (4) Effects of elevated nutrient concentrations on the river; and (5) Actions to reduce river nutrient concentrations and flux. Nutrient concentration and flux in the Mississippi River have increased substantially over the last century because of changes in land use, climate, hydrology, and river management and engineering. As in other large floodplain rivers, rates of processes that cycle nitrogen and phosphorus in the UMR exhibit pronounced spatial and temporal heterogeneity because of the complex morphology of the river. This spatial variability in nutrient processing creates clear spatial patterns in nutrient concentrations. For example, nitrate concentrations generally are much lower in off-channel areas than in the main channel. The specifics of in-river nutrient cycling and the effects of high rates of nutrient input on UMR have been less studied than the factors affecting nutrient input to the river and transport to the Gulf of Mexico, and important questions concerning nutrient cycling in the UMR remain. Eutrophication and resulting changes in river productivity have only recently been investigated the UMR. These recent studies indicate that the high nutrient concentrations in the river may affect community composition of aquatic vegetation (e. g., the abundance of filamentous algae and duckweeds), dissolved oxygen concentrations in off-channel areas, and the abundance of cyanobacteria. Actions to reduce nutrient input to the river include changes in land-use practices, wetland restoration, and hydrological modifications to the river. Evidence suggests that most of the above methods can contribute to reducing nutrient concentration in

  10. Bayesian methods for spatial upscaling of process-based forest ecosystem models

    NASA Astrophysics Data System (ADS)

    van Oijen, M.; Cameron, D.; Reinds, G.; Thomson, A.

    2010-12-01

    Forest ecosystem models are common tools in environmental research: 78 different ones are listed by REM (http://ecobas.org/www-server/index.html). They tend to be process-based, parameter-rich simulators of biogeochemical fluxes at the point-support scale. Model inputs (weather, soil) should thus be provided at point-support too, rather than as regional averages. The high computational demand and point-support hampers the use of the models for larger regions. Models have been applied regionally, but without assessment of uncertainties due to upscaling from point to region. Bayesian methods are increasingly used to quantify parametric and structural uncertainties of forest models (Van Oijen et al. 2005), made possible by improvement in computing power and calibration algorithms such as MCMC. We present two case-studies of regional model application where we used MCMC to quantify uncertainties. The first study concerns Bayesian calibration of the VSD soil acidification model using European forest monitoring data (Reinds et al. 2008). Single-site calibration, applied separately to 122 sites, effectively converted prior parameter uncertainty into spatial variability. In contrast, multiple-site calibration, using the data from all sites simultaneously to estimate a common parameter vector, led to asymptotic collapse of the parameter distribution. The narrow posterior parameter distribution caused 20-100% higher values of NRMSE on 60 test sites than using nearest-neighbour single-site calibration results. Next, we applied the forest model BASFOR to the U.K. at a 20 x 20 km grid, to calculate carbon accumulation in biomass and soil (Van Oijen & Thomson 2010), as part of the U.K.’s Greenhouse Gas Inventory. For each grid cell, the model was run multiple times by taking different samples from the parameter distribution determined by a preceding Bayesian calibration. This allowed us to draw up a map of the spatial distribution of model output uncertainty. Uncertainty was

  11. Processes affecting the CO2 concentrations measured in Greenland ice

    NASA Astrophysics Data System (ADS)

    Anklin, Martin; Barnola, Jean-Marc; Schwander, Jakob; Stauffer, Bernhard; Raynaud, Dominique

    1995-09-01

    Detailed CO2 measurements on ice cores from Greenland and Antarctica show different mean CO2 concentrations for samples at the same gas age. The deviation between Antarctic and Greenland CO2 records raises up to 20 ppmv during the last millennium. Based on the present knowledge of the global carbon cycle we can exclude such a high mean interhemispheric difference of the CO2 concentration between high northern and southern latitudes. Diffusive mixing of the air in the firn smoothes out short term variations of the atmospheric CO2 Concentration. Nevertheless, we observe short term CO2 variations in Greenland ice in the range of 10 20 ppmv, which cannot represent atmospheric CO2 variations. Due to the low temperature at Summit, meltlayers can be excluded for most of the ice and they cannot account for the frequent anomalous short term CO2 variations and the elevated mean CO2 concentration in the Greenland ice. In this work we give some clues, that in situ production of CO2 in Greenland ice could build up excess CO2 after pore close of. Possible chemical reactions are the oxidation of organic carbon and the reaction between acidity and carbonate. We conclude that the carbonate-acidity reaction is the most probable process to explain the excess CO2 in the bubbles. The reaction could take place in very small liquid-like veins in cold ice, where the mobility of impurities is higher than in the ice lattice. At present, there exists no technique to measure the carbonate concentration in the ice directly. However, a comparison of CO2 analyses performed with a dry- and a wet-extraction technique allows to estimate the carbonate content of the ice. This estimate indicates a carbonate concentration in Greenland ice of about 0.4±0.2µmol/l and a much lower concentration in Antarctic ice.

  12. ECOSYSTEM GROWTH AND DEVELOPMENT

    EPA Science Inventory

    Thermodynamically, ecosystem growth and development is the process by which energy throughflow and stored biomass increase. Several proposed hypotheses describe the natural tendencies that occur as an ecosystem matures, and here, we consider five: minimum entropy production, maxi...

  13. Volcano ecology at Chaiten, Chile: geophysical processes interact with forest ecosystems

    NASA Astrophysics Data System (ADS)

    Swanson, F. J.; Crisafulli, C.; Jones, J. A.; Lara, A.

    2010-12-01

    The May 2008 eruption of Chaiten Volcano (Chile) offers many insights into volcano ecology -ecological responses to volcanic and associated hydrologic processes and ecosystem development in post-eruption landscapes. Varied intensities of pyroclastic density currents (PDC) and thickness of tephra fall deposits (to 50+ cm) created strong gradients of disturbance in several hundred square kilometers of native forest in a sector north to southeast from the volcano. A gradient from tree removal to toppled forest to standing, scorched forest extends 1.5 km northward from the caldera rim along the trajectory of a PDC. Close to the vent (e.g., 2 km NE from rim) a rain of ca. 10 cm of gravel tephra stripped foliage and twigs from tree canopies; farther away (23 km SE) 10 cm of fine tephra loaded the canopy, causing extensive fall of limbs >8 cm diameter. Even in the severely disturbed, north-flank PDC zone, surviving bamboo, ferns, and other herbs sprouted from pre-eruption soil and other refugia; sprouts of new foliage appeared on the boles and major limbs of several species of toppled and scorched, standing trees; animals including vertebrates (rodents and amphibians) and terrestrial invertebrates (e.g., insects and arachnids) either survived or quickly recolonized; and a diverse fungal community began decomposing the vast dead wood resource. During the second growing season we documented the presence of some plant species that had colonized by seed. Within two years after the eruption secondary ecological disturbances resulting from channel change and overbank deposition of fluvially transported tephra created new patches of damaged forest in riparian zones of streams draining the north flank and along the Rio Rayas and Rio Chaiten. These features parallel observations in the intensively-studied, post-1980-eruption landscape of Mount St. Helens over a similar time period. However, several aspects of ecological response to the two eruptions differ because of differences

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

    PubMed

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

    2008-12-01

    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.

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

    PubMed

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

    2008-12-01

    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. PMID:18707753

  16. Process contributions of Australian ecosystems to interannual variations in the carbon cycle

    NASA Astrophysics Data System (ADS)

    Haverd, Vanessa; Smith, Benjamin; Trudinger, Cathy

    2016-05-01

    New evidence is emerging that semi-arid ecosystems dominate interannual variability (IAV) of the global carbon cycle, largely via fluctuating water availability associated with El Niño/Southern Oscillation. Recent evidence from global terrestrial biosphere modelling and satellite-based inversion of atmospheric CO2 point to a large role of Australian ecosystems in global carbon cycle variability, including a large contribution from Australia to the record land sink of 2011. However the specific mechanisms governing this variability, and their bioclimatic distribution within Australia, have not been identified. Here we provide a regional assessment, based on best available observational data, of IAV in the Australian terrestrial carbon cycle and the role of Australia in the record land sink anomaly of 2011. We find that IAV in Australian net carbon uptake is dominated by semi-arid ecosystems in the east of the continent, whereas the 2011 anomaly was more uniformly spread across most of the continent. Further, and in contrast to global modelling results suggesting that IAV in Australian net carbon uptake is amplified by lags between production and decomposition, we find that, at continental scale, annual variations in production are dampened by annual variations in decomposition, with both fluxes responding positively to precipitation anomalies.

  17. Richness, biomass, and nutrient content of a wetland macrophyte community affect soil nitrogen cycling in a diversity-ecosystem functioning experiment

    USGS Publications Warehouse

    Korol, Alicia R.; Ahn, Changwoo; Noe, Gregory

    2016-01-01

    The development of soil nitrogen (N) cycling in created wetlands promotes the maturation of multiple biogeochemical cycles necessary for ecosystem functioning. This development proceeds from gradual changes in soil physicochemical properties and influential characteristics of the plant community, such as competitive behavior, phenology, productivity, and nutrient composition. In the context of a 2-year diversity experiment in freshwater mesocosms (0, 1, 2, 3, or 4 richness levels), we assessed the direct and indirect impacts of three plant community characteristics – species richness, total biomass, and tissue N concentration – on three processes in the soil N cycle – soil net ammonification, net nitrification, and denitrification potentials. Species richness had a positive effect on net ammonification potential (NAP) through higher redox potentials and likely faster microbial respiration. All NAP rates were negative, however, due to immobilization and high rates of ammonium removal. Net nitrification was inhibited at higher species richness without mediation from the measured soil properties. Higher species richness also inhibited denitrification potential through increased redox potential and decreased nitrification. Both lower biomass and/or higher tissue ratios of carbon to nitrogen, characteristics indicative of the two annual plants, were shown to have stimulatory effects on all three soil N processes. The two mediating physicochemical links between the young macrophyte community and microbial N processes were soil redox potential and temperature. Our results suggest that early-successional annual plant communities play an important role in the development of ecosystem N multifunctionality in newly created wetland soils.

  18. Generalizability of Gottman and Colleagues' Affective Process Models Of Couples' Relationship Outcomes

    ERIC Educational Resources Information Center

    Kim, Hyoun K.; Capaldi, Deborah M.; Crosby, Lynn

    2007-01-01

    The generalizability of the affective process models of J. M. Gottman et al. (1998) was examined using a community-based sample of 85 married or cohabiting couples with at-risk backgrounds. Predictive associations between affective processes assessed at about age 21 years and relationship status and satisfaction assessed approximately 2.5 years…

  19. Environmental Impacts of the Use of Ecosystem Services: Case Study of Birdwatching

    NASA Astrophysics Data System (ADS)

    Kronenberg, Jakub

    2014-09-01

    The main reason for promoting the concept of ecosystem services lies in its potential to contribute to environmental conservation. Highlighting the benefits derived from ecosystems fosters an understanding of humans' dependence on nature, as users of ecosystem services. However, the act of using ecosystem services may not be environmentally neutral. As with the use of products and services generated within an economy, the use of ecosystem services may lead to unintended environmental consequences throughout the `ecosystem services supply chain.' This article puts forward a framework for analyzing environmental impacts related to the use of ecosystem services, indicating five categories of impact: (1) direct impacts (directly limiting the service's future availability); and four categories of indirect impacts, i.e., on broader ecosystem structures and processes, which can ultimately also affect the initial service: (2) impacts related to managing ecosystems to maximize the delivery of selected services (affecting ecosystems' capacity to provide other services); (3) impacts associated with accessing ecosystems to use their services (affecting other ecosystem components); (4) additional consumption of products, infrastructure or services required to use a selected ecosystem service, and their life-cycle environmental impacts; and (5) broader impacts on the society as a whole (environmental awareness of ecosystem service users and other stakeholders). To test the usefulness of this framework, the article uses the case study of birdwatching, which demonstrates all of the above categories of impacts. The article justifies the need for a broader consideration of environmental impacts related to the use of ecosystem services.

  20. Environmental impacts of the use of ecosystem services: case study of birdwatching.

    PubMed

    Kronenberg, Jakub

    2014-09-01

    The main reason for promoting the concept of ecosystem services lies in its potential to contribute to environmental conservation. Highlighting the benefits derived from ecosystems fosters an understanding of humans' dependence on nature, as users of ecosystem services. However, the act of using ecosystem services may not be environmentally neutral. As with the use of products and services generated within an economy, the use of ecosystem services may lead to unintended environmental consequences throughout the 'ecosystem services supply chain.' This article puts forward a framework for analyzing environmental impacts related to the use of ecosystem services, indicating five categories of impact: (1) direct impacts (directly limiting the service's future availability); and four categories of indirect impacts, i.e., on broader ecosystem structures and processes, which can ultimately also affect the initial service: (2) impacts related to managing ecosystems to maximize the delivery of selected services (affecting ecosystems' capacity to provide other services); (3) impacts associated with accessing ecosystems to use their services (affecting other ecosystem components); (4) additional consumption of products, infrastructure or services required to use a selected ecosystem service, and their life-cycle environmental impacts; and (5) broader impacts on the society as a whole (environmental awareness of ecosystem service users and other stakeholders). To test the usefulness of this framework, the article uses the case study of birdwatching, which demonstrates all of the above categories of impacts. The article justifies the need for a broader consideration of environmental impacts related to the use of ecosystem services. PMID:24993794

  1. Up-scaling Stream Ecosystem Processes to Predict the Effects of Land Cover Change at a Watershed Scale in the Atlantic Tropical Rainforest.

    NASA Astrophysics Data System (ADS)

    Tromboni, F.; Feijó de Lima, R.; Silva-Júnior, E. F.; Lourenço-Amorim, C.; Zandoná, E.; Moulton, T. P.; Da Silva, B. S.; Silva-Araújo, M.; Thomas, S. A.

    2015-12-01

    Riparian land-cover change (LCC) causes a cascade of subsequent hierarchical effects that propagate through abiotic compartments until reaching the biota, altering stream ecosystem functioning. Due to the movement of water downstream, these lateral effects co-occur with longitudinal influences. We investigated both the lateral and longitudinal effects of deforestation in four streams in the Atlantic tropical rainforest of Brazil. We collected physical-chemical, geomorphic, hydrological data and samples of macroinvertebrates assemblages. We then categorized land cover at different scales (from different riparian and reach buffer sizes to sub and total watershed) using a SPOT-5 satellite image and ArcGIS. We also carried out a series of experiments along the streams to understand: 1) the mechanisms by which LCC affects periphyton and how these changes alter metabolism and nutrient uptake rates; 2) the downstream distance at which periphyton and the associated variables change in the transitions from one riparian category to the other. We used (i) a path analysis to test if our hypothesized land-cover cascade model described our data and (ii) non-linear models to describe the longitudinal effect on each variable. Our results showed that deforestation produced a range of physical changes at different spatial scale, longitudinally altering periphyton taxonomic composition (taxa depending on light), stoichiometry (nutritionally richer with increasing deforestation) and growth rates (greater in deforested). Macroinvertebrate assemblages behaved similarly to chlorophyll a in response to forest loss. Respiration rate increased with deforestation probably due to higher nutrient concentrations but primary production did not increase. Models were used to upscale LCC impacts on ecosystem processes from local scale experiments to landscape and our work has important implications for socio-economic decisions concerning ecosystem management and conservation.

  2. 76 FR 30509 - Court Orders and Legal Processes Affecting Thrift Savings Plan Accounts

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-26

    ... Part 1653 Court Orders and Legal Processes Affecting Thrift Savings Plan Accounts AGENCY: Federal... finalize the process by which TSP accounts may be garnished efficiently--consistent with law and regulation... is trying to process more than 7,000 child support orders. If the Agency processes these orders...

  3. The constructed catchment 'Chicken Creek' - a landscape observatory to analyze processes and feedback mechanisms during initial ecosystem development

    NASA Astrophysics Data System (ADS)

    Elmer, Michael; Schaaf, Wolfgang; Gerwin, Werner; Hinz, Christoph

    2014-05-01

    We investigated the initial development of the landscape observatory 'Chicken Creek', Germany, an artificial catchment with well known boundary conditions and inner structures (Gerwin et al., 2011). Over a period of nine years, we observed considerable changes within the site (Elmer et al., 2013). Both internal and external factors could be identified as driving forces for the formation of structures and patterns in the catchment. Over time, secondary structures and patterns evolved and became more and more important. Invading biota and vegetation succession initialized feedback mechanisms resulting in pattern and habitat formation as well as in increased differentiation, heterogeneity and complexity that are typical characteristics of ecosystems (Schaaf et al., 2013). The processes and feedback mechanisms in the initial development of a new landscape may deviate in rates, intensity, and dominance from those known from mature ecosystems. It is therefore crucial to understand these early phases of ecosystem development and to disentangle the increasingly complex interactions between the evolving terrestrial and aquatic, biotic, and abiotic compartments of the system. Elmer M, Gerwin W, Schaaf W, Zaplata MK, Hohberg K, Nenov R, Bens O, Hüttl RF (2013): Dynamics of initial ecosystem development at the artificial catchment Chicken Creek, Lusatia, Germany. Environ Earth Sci 69, 491-505. Gerwin W, Schaaf W, Biemelt D, Winter S, Fischer A, Veste M, Hüttl RF (2011): Overview and first results of ecological monitoring at the artificial watershed Chicken Creek (Germany). Phys Chem Earth 36, 61-73. Schaaf W, Elmer M, Fischer A, Gerwin W, Nenov R, Pretsch H, Seifert S, Winter S, Zaplata MK (2013): Monitoring the formation of structures and patterns during initial development of an artificial catchment. Environ Monit Assess 185, 5965-5986.

  4. Continental Margins: Linking Ecosystems

    NASA Astrophysics Data System (ADS)

    Kelly-Gerreyn, Boris; Rabalais, Nancy; Middelburg, Jack; Roy, Sylvie; Liu, Kon-Kee; Thomas, Helmuth; Zhang, Jing

    2008-02-01

    Impacts of Global, Local and Human Forcings on Biogeochemical Cycles and Ecosystems, IMBER/LOICZ Continental Margins Open Science Conference; Shanghai, China, 17-21 September 2007; More than 100 scientists from 25 countries came together to address global, regional, local, and human pressures interactively affecting continental margin biogeochemical cycles, marine food webs, and society. Continental margins cover only 12% of the global ocean area yet account for more than 30% of global oceanic primary production. In addition, continental margins are the most intensely used regions of the world's ocean for natural commodities, including productive fisheries and mineral and petroleum resources. The land adjacent to continental margins hosts about 50% of the world's population, which will bear many direct impacts of global change on coastal margins. Understanding both natural and human-influenced alterations of biogeochemical cycles and ecosystems on continental margins and the processes (including feedbacks) that threaten sustainability of these systems is therefore of global interest.

  5. Ecosystem change and stability over multiple decades in the Swedish subarctic: complex processes and multiple drivers

    PubMed Central

    Callaghan, Terry V; Jonasson, Christer; Thierfelder, Tomas; Yang, Zhenlin; Hedenås, Henrik; Johansson, Margareta; Molau, Ulf; Van Bogaert, Rik; Michelsen, Anders; Olofsson, Johan; Gwynn-Jones, Dylan; Bokhorst, Stef; Phoenix, Gareth; Bjerke, Jarle W.; Tømmervik, Hans; Christensen, Torben R.; Hanna, Edward; Koller, Eva K.; Sloan, Victoria L.

    2013-01-01

    The subarctic environment of northernmost Sweden has changed over the past century, particularly elements of climate and cryosphere. This paper presents a unique geo-referenced record of environmental and ecosystem observations from the area since 1913. Abiotic changes have been substantial. Vegetation changes include not only increases in growth and range extension but also counterintuitive decreases, and stability: all three possible responses. Changes in species composition within the major plant communities have ranged between almost no changes to almost a 50 per cent increase in the number of species. Changes in plant species abundance also vary with particularly large increases in trees and shrubs (up to 600%). There has been an increase in abundance of aspen and large changes in other plant communities responding to wetland area increases resulting from permafrost thaw. Populations of herbivores have responded to varying management practices and climate regimes, particularly changing snow conditions. While it is difficult to generalize and scale-up the site-specific changes in ecosystems, this very site-specificity, combined with projections of change, is of immediate relevance to local stakeholders who need to adapt to new opportunities and to respond to challenges. Furthermore, the relatively small area and its unique datasets are a microcosm of the complexity of Arctic landscapes in transition that remains to be documented. PMID:23836792

  6. Role of Boreal Vegetation in Controlling Ecosystem Processes and Feedbacks to Climate

    NASA Technical Reports Server (NTRS)

    Chapin, F. S., III; Hooper, D. U.; Hobbie, S. E.; Verville, J. H.

    1997-01-01

    In the field, dark respiration rates are greatest in cores from more northerly locations. This is due in part to greater amounts of dwarf shrub biomass in the more northerly cores, but also to differences in soil organic matter quality. Laboratory incubations of these soils under common conditions show some evidence for greater pools of available carbon in soils from more northerly tundra sites, although the most northerly site does not fit this pattern for reasons which are unclear at this time. While field measurements of cores transplanted among different vegetation types at the same location (Toolik Lake) show relatively small differences in whole ecosystem carbon flux, laboratory incubation of these same soils shows that there are large differences in soil respiration rates under common conditions. This is presumably due to differences in organic matter quality. Microenvironmental site factors (temperature, soil moisture, degree of anaerobiosis, etc.) may be responsible for evening out these differences in the field. These site factors, which differ with slope, aspect, and drainage within a given location along the latitudinal gradient, appear to exert at least as strong a control over carbon fluxes as do macroclimatic factors among sites across the latitudinal gradient. While our field measurements indicate that, in the short term, warming will tend to increase ecosystem losses Of CO2 via respiration more than they will increase plant gross assimilation, the degree to which different topographically-defined plant communities will respond is likely to vary.

  7. Deposition and processing of airborne nitrogen pollutants in Mediterranean-type ecosystems of southern California

    SciTech Connect

    Riggan P.J.; Lockwood, R.N.; Lopez, E.N.

    1985-09-01

    Atmospheric nitrogen deposition, associated with chronic urban air pollution, has produced stream water nitrate concentrations as high as 7.0 mg of N L/sup -1/ in chaparral watershed in the San Gabriel Mountains of Los Angeles County, CA. Stream water (NO/sub 3//sup -/) and discharge were greatest at high flow and may contribute significantly to existing groundwater NO/sub 3//sup -/ pollution. Annual NO/sub 3//sup -/ discharge ranged from 0.04 to 10.0 kg of N ha/sup -1/ over 4 years. Canopy throughfall and precipitation inputs of 23.3 and 8.2 kg of N ha/sup -1/ year/sup -1/ were high relative to other undisturbed ecosystems nationwide. Dry deposition was apparently a major source of the throughfall nitrogen. NO/sub 3//sup -/ concentrations from nearby, relatively unpolluted watersheds were lower by 1-3 orders of magnitude. NO/sub 3//sup -/ yield was elevated on watersheds where chaparral was converted to grassland in 1960 and may be greatly accelerated after wildfire because of high postfire NH/sub 4//sup +/ concentrations and rapid nitrification in terrestrial and aquatic ecosystems.

  8. Plant Host Species and Geographic Distance Affect the Structure of Aboveground Fungal Symbiont Communities, and Environmental Filtering Affects Belowground Communities in a Coastal Dune Ecosystem.

    PubMed

    David, Aaron S; Seabloom, Eric W; May, Georgiana

    2016-05-01

    Microbial symbionts inhabit tissues of all plants and animals. Their community composition depends largely on two ecological processes: (1) filtering by abiotic conditions and host species determining the environments that symbionts are able to colonize and (2) dispersal-limitation determining the pool of symbionts available to colonize a given host and community spatial structure. In plants, the above- and belowground tissues represent such distinct habitats for symbionts that we expect different effects of filtering and spatial structuring on their symbiont communities. In this study, we characterized above- and belowground communities of fungal endophytes--fungi living asymptomatically within plants--to understand the contributions of filtering and spatial structure to endophyte community composition. We used a culture-based approach to characterize endophytes growing in leaves and roots of three species of coastal beachgrasses in dunes of the USA Pacific Northwest. For leaves, endophyte isolation frequency and OTU richness depended primarily on plant host species. In comparison, for roots, both isolation frequency and OTU richness increased from the nutrient-poor front of the dune to the higher-nutrient backdune. Endophyte community composition in leaves exhibited a distance-decay relationship across the region. In a laboratory assay, faster growth rates and lower spore production were more often associated with leaf- than root-inhabiting endophytes. Overall, our results reveal a greater importance of biotic filtering by host species and dispersal-limitation over regional geographic distances for aboveground leaf endophyte communities and stronger effects of abiotic environmental filtering and locally patchy distributions for belowground root endophyte communities. PMID:26626912

  9. Science for managing ecosystem services: Beyond the Millennium Ecosystem Assessment.

    PubMed

    Carpenter, Stephen R; Mooney, Harold A; Agard, John; Capistrano, Doris; Defries, Ruth S; Díaz, Sandra; Dietz, Thomas; Duraiappah, Anantha K; Oteng-Yeboah, Alfred; Pereira, Henrique Miguel; Perrings, Charles; Reid, Walter V; Sarukhan, José; Scholes, Robert J; Whyte, Anne

    2009-02-01

    The Millennium Ecosystem Assessment (MA) introduced a new framework for analyzing social-ecological systems that has had wide influence in the policy and scientific communities. Studies after the MA are taking up new challenges in the basic science needed to assess, project, and manage flows of ecosystem services and effects on human well-being. Yet, our ability to draw general conclusions remains limited by focus on discipline-bound sectors of the full social-ecological system. At the same time, some polices and practices intended to improve ecosystem services and human well-being are based on untested assumptions and sparse information. The people who are affected and those who provide resources are increasingly asking for evidence that interventions improve ecosystem services and human well-being. New research is needed that considers the full ensemble of processes and feedbacks, for a range of biophysical and social systems, to better understand and manage the dynamics of the relationship between humans and the ecosystems on which they rely. Such research will expand the capacity to address fundamental questions about complex social-ecological systems while evaluating assumptions of policies and practices intended to advance human well-being through improved ecosystem services. PMID:19179280

  10. Science for managing ecosystem services: Beyond the Millennium Ecosystem Assessment

    PubMed Central

    Carpenter, Stephen R.; Mooney, Harold A.; Agard, John; Capistrano, Doris; DeFries, Ruth S.; Díaz, Sandra; Dietz, Thomas; Duraiappah, Anantha K.; Oteng-Yeboah, Alfred; Pereira, Henrique Miguel; Perrings, Charles; Reid, Walter V.; Sarukhan, José; Scholes, Robert J.; Whyte, Anne

    2009-01-01

    The Millennium Ecosystem Assessment (MA) introduced a new framework for analyzing social–ecological systems that has had wide influence in the policy and scientific communities. Studies after the MA are taking up new challenges in the basic science needed to assess, project, and manage flows of ecosystem services and effects on human well-being. Yet, our ability to draw general conclusions remains limited by focus on discipline-bound sectors of the full social–ecological system. At the same time, some polices and practices intended to improve ecosystem services and human well-being are based on untested assumptions and sparse information. The people who are affected and those who provide resources are increasingly asking for evidence that interventions improve ecosystem services and human well-being. New research is needed that considers the full ensemble of processes and feedbacks, for a range of biophysical and social systems, to better understand and manage the dynamics of the relationship between humans and the ecosystems on which they rely. Such research will expand the capacity to address fundamental questions about complex social–ecological systems while evaluating assumptions of policies and practices intended to advance human well-being through improved ecosystem services. PMID:19179280

  11. The interactive effects of fire and diversity on short-term responses of ecosystem processes in experimental mediterranean grasslands.

    PubMed

    Dimitrakopoulos, Panayiotis G; Siamantziouras, Akis-Stavros D; Galanidis, Alexandros; Mprezetou, Irene; Troumbis, Andreas Y

    2006-06-01

    We conducted a field experiment using constructed communities to test whether species richness contributed to the maintenance of ecosystem processes under fire disturbance. We studied the effects of diversity components (i.e., species richness and species composition) upon productivity, structural traits of vegetation, decomposition rates, and soil nutrients between burnt and unburnt experimental Mediterranean grassland communities. Our results demonstrated that fire and species richness had interactive effects on aboveground biomass production and canopy structure components. Fire increased biomass production of the highest-richness communities. The effects of fire on aboveground biomass production at different levels of species richness were derived from changes in both vertical and horizontal canopy structure of the communities. The most species-rich communities appeared to be more resistant to fire in relation to species-poor ones, due to both compositional and richness effects. Interactive effects of fire and species richness were not important for belowground processes. Decomposition rates increased with species richness, related in part to increased levels of canopy structure traits. Fire increased soil nutrients and long-term decomposition rate. Our results provide evidence that composition within richness levels had often larger effects on the stability of aboveground ecosystem processes in the face of fire disturbance than species richness per se. PMID:16514480

  12. Diagnosis of Processes Controlling Dissolved Organic Carbon (DOC) Export in a Subarctic Region by a Dynamic Ecosystem Model

    NASA Astrophysics Data System (ADS)

    Tang, J.

    2015-12-01

    Permafrost thawing in high latitudes allows more soil organic carbon (SOC) to become hydrologically accessible. This can increase dissolved organic carbon (DOC) exports and carbon release to the atmosphere as CO2 and CH4, with a positive feedback to regional and global climate warming. However, this portion of carbon loss through DOC export is often neglected in ecosystem models. In this paper, we incorporate a set of DOC-related processes (DOC production, mineralization, diffusion, sorption-desorption and leaching) into an Arctic-enabled version of the dynamic ecosystem model LPJ-GUESS (LPJ-GUESS WHyMe) to mechanistically model the DOC export, and to link this flux to other ecosystem processes. The extended LPJ-GUESS WHyMe with these DOC processes is applied to the Stordalen catchment in northern Sweden. The relative importance of different DOC-related processes for mineral and peatland soils for this region have been explored at both monthly and annual scales based on a detailed variance-based Sobol sensitivity analysis. For mineral soils, the annual DOC export is dominated by DOC fluxes in snowmelt seasons and the peak in spring is related to the runoff passing through top organic rich layers. Two processes, DOC sorption-desorption and production, are found to contribute most to the annual variance in DOC export. For peatland soils, the DOC export during snowmelt seasons is constrained by frozen soils and the processes of DOC production and mineralization, determining the magnitudes of DOC desorption in snowmelt seasons as well as DOC sorption in the rest of months, play the most important role in annual variances of DOC export. Generally, the seasonality of DOC fluxes is closely correlated with runoff seasonality in this region. The current implementation has demonstrated that DOC-related processes in the framework of LPJ-GUESS WHyMe are at an appropriate level of complexity to represent the main mechanism of DOC dynamics in soils. The quantified contributions

  13. Potential for real-time understanding of coupled hydrologic and biogeochemical processes in stream ecosystems: Future integration of telemetered data with process models for glacial meltwater streams

    NASA Astrophysics Data System (ADS)

    McKnight, Diane M.; Cozzetto, Karen; Cullis, James D. S.; Gooseff, Michael N.; Jaros, Christopher; Koch, Joshua C.; Lyons, W. Berry; Neupauer, Roseanna; Wlostowski, Adam

    2015-08-01

    While continuous monitoring of streamflow and temperature has been common for some time, there is great potential to expand continuous monitoring to include water quality parameters such as nutrients, turbidity, oxygen, and dissolved organic material. In many systems, distinguishing between watershed and stream ecosystem controls can be challenging. The usefulness of such monitoring can be enhanced by the application of quantitative models to interpret observed patterns in real time. Examples are discussed primarily from the glacial meltwater streams of the McMurdo Dry Valleys, Antarctica. Although the Dry Valley landscape is barren of plants, many streams harbor thriving cyanobacterial mats. Whereas a daily cycle of streamflow is controlled by the surface energy balance on the glaciers and the temporal pattern of solar exposure, the daily signal for biogeochemical processes controlling water quality is generated along the stream. These features result in an excellent outdoor laboratory for investigating fundamental ecosystem process and the development and validation of process-based models. As part of the McMurdo Dry Valleys Long-Term Ecological Research project, we have conducted field experiments and developed coupled biogeochemical transport models for the role of hyporheic exchange in controlling weathering reactions, microbial nitrogen cycling, and stream temperature regulation. We have adapted modeling approaches from sediment transport to understand mobilization of stream biomass with increasing flows. These models help to elucidate the role of in-stream processes in systems where watershed processes also contribute to observed patterns, and may serve as a test case for applying real-time stream ecosystem models.

  14. Effects of acidic deposition on nutrient uptake, nutrient cycling and growth processes of vegetation in the spruce-fir ecosystem

    SciTech Connect

    McLaughlin, S.B.; Garten, C.T.; Wullschleger, S.D.

    1996-10-16

    This report summarizes progress in three years of field research designed to evaluate biological and chemical indicators of the current and future health of the Southern Appalachian spruce-fir ecosystem. The emphasis of this research has been on the identification and understanding of mechanisms through which current levels of acidic deposition are impacting ecosystem processes. The identification of these principal mechanisms and key biological indicators of change was designed to improve our capabilities to detect, monitor, and assess the effects of air quality regulations and attendant future air quality changes on ecosystem response. Individual research tasks focused on the following research areas: (1) the significance of foliar uptake of atmospheric sources of nitrogen in relationship to plant utilization of N from available soil reserves; (2) linkages between atmospheric inputs to the soil surface, solution chemistry, and decomposition in the upper organic soil horizons; (3) effects of soil solution chemistry on uptake of cations and aluminum by fine roots; and (4) the effects of varying rates of calcium supply on carbon metabolism of Fraser fir and red spruce, and the relationship between calcium levels in wood cells and integrity of wood formed in bole and branches. Each of the individual tasks was designed to focus upon a mechanism or process that we consider critical to understanding chemical and biological linkages. These linkages will be important determinants in understanding the basis of past and potential future responses of the high elevation Southern Appalachian Forest to acidic deposition and other co-occurring environmental stresses. This report contains (1) background and rationale for the research undertaken in 1992-94; (2) a summary of principal research findings; (3) publications from this research; and (4) characterization of data sets produced by this research which will be the basis of future research, analyses and/or publications.

  15. Nutrient limitation on ecosystem productivity and processes of mature and old-growth subtropical forests in China.

    PubMed

    Hou, Enqing; Chen, Chengrong; McGroddy, Megan E; Wen, Dazhi

    2012-01-01

    Nitrogen (N) is considered the dominant limiting nutrient in temperate regions, while phosphorus (P) limitation frequently occurs in tropical regions, but in subtropical regions nutrient limitation is poorly understood. In this study, we investigated N and P contents and N:P ratios of foliage, forest floors, fine roots and mineral soils, and their relationships with community biomass, litterfall C, N and P productions, forest floor turnover rate, and microbial processes in eight mature and old-growth subtropical forests (stand age >80 yr) at Dinghushan Biosphere Reserve, China. Average N:P ratios (mass based) in foliage, litter (L) layer and mixture of fermentation and humus (F/H) layer, and fine roots were 28.3, 42.3, 32.0 and 32.7, respectively. These values are higher than the critical N:P ratios for P limitation proposed (16-20 for foliage, ca. 25 for forest floors). The markedly high N:P ratios were mainly attributed to the high N concentrations of these plant materials. Community biomass, litterfall C, N and P productions, forest floor turnover rate and microbial properties were more strongly related to measures of P than N and frequently negatively related to the N:P ratios, suggesting a significant role of P availability in determining ecosystem production and productivity and nutrient cycling at all the study sites except for one prescribed disturbed site where N availability may also be important. We propose that N enrichment is probably a significant driver of the potential P limitation in the study area. Low P parent material may also contribute to the potential P limitation. In general, our results provided strong evidence supporting a significant role for P availability, rather than N availability, in determining ecosystem primary productivity and ecosystem processes in subtropical forests of China.

  16. Nutrient Limitation on Ecosystem Productivity and Processes of Mature and Old-Growth Subtropical Forests in China

    PubMed Central

    Hou, Enqing; Chen, Chengrong; McGroddy, Megan E.; Wen, Dazhi

    2012-01-01

    Nitrogen (N) is considered the dominant limiting nutrient in temperate regions, while phosphorus (P) limitation frequently occurs in tropical regions, but in subtropical regions nutrient limitation is poorly understood. In this study, we investigated N and P contents and N:P ratios of foliage, forest floors, fine roots and mineral soils, and their relationships with community biomass, litterfall C, N and P productions, forest floor turnover rate, and microbial processes in eight mature and old-growth subtropical forests (stand age >80 yr) at Dinghushan Biosphere Reserve, China. Average N:P ratios (mass based) in foliage, litter (L) layer and mixture of fermentation and humus (F/H) layer, and fine roots were 28.3, 42.3, 32.0 and 32.7, respectively. These values are higher than the critical N:P ratios for P limitation proposed (16–20 for foliage, ca. 25 for forest floors). The markedly high N:P ratios were mainly attributed to the high N concentrations of these plant materials. Community biomass, litterfall C, N and P productions, forest floor turnover rate and microbial properties were more strongly related to measures of P than N and frequently negatively related to the N:P ratios, suggesting a significant role of P availability in determining ecosystem production and productivity and nutrient cycling at all the study sites except for one prescribed disturbed site where N availability may also be important. We propose that N enrichment is probably a significant driver of the potential P limitation in the study area. Low P parent material may also contribute to the potential P limitation. In general, our results provided strong evidence supporting a significant role for P availability, rather than N availability, in determining ecosystem primary productivity and ecosystem processes in subtropical forests of China. PMID:23284873

  17. Wood phenology: from organ-scale processes to terrestrial ecosystem models

    NASA Astrophysics Data System (ADS)

    Delpierre, Nicolas; Guillemot, Joannès

    2016-04-01

    In temperate and boreal trees, a dormancy period prevents organ development during adverse climatic conditions. Whereas the phenology of leaves and flowers has received considerable attention, to date, little is known regarding the phenology of other tree organs such as wood, fine roots, fruits and reserve compounds. In this presentation, we review both the role of environmental drivers in determining the phenology of wood and the models used to predict its phenology in temperate and boreal forest trees. Temperature is a key driver of the resumption of wood activity in spring. There is no such clear dominant environmental cue involved in the cessation of wood formation in autumn, but temperature and water stress appear as prominent factors. We show that wood phenology is a key driver of the interannual variability of wood growth in temperate tree species. Incorporating representations of wood phenology in a terrestrial ecosystem model substantially improved the simulation of wood growth under current climate.

  18. Study of individual and group affective processes in the crew of a simulated mission to Mars: Positive affectivity as a valuable indicator of changes in the crew affectivity

    NASA Astrophysics Data System (ADS)

    Poláčková Šolcová, Iva; Lačev, Alek; Šolcová, Iva

    2014-07-01

    The success of a long-duration space mission depends on various technical demands as well as on the psychological (cognitive, affective, and motivational) adaptation of crewmembers and the quality of interactions within the crew. We examined the ways crewmembers of a 520-day simulated spaceflight to Mars (held in the Institute for Biomedical Problems, in Moscow) experienced and regulated their moods and emotions. Results show that crewmembers experienced predominantly positive emotions throughout their 520-day isolation and the changes in mood of the crewmembers were asynchronous and balanced. The study suggests that during the simulation, crewmembers experienced and regulated their emotions differently than they usually do in their everyday life. In isolation, crewmembers preferred to suppress and neutralize their negative emotions and express overtly only emotions with positive valence. Although the affective processes were almost invariable throughout the simulation, two periods of time when the level of positive emotions declined were identified. Regarding the findings, the paper suggests that changes in positive affectivity could be a more valuable indicator of human experience in demanding but professional environments than changes in negative affectivity. Finally, the paper discusses the phenomenology of emotions during a real space mission.

  19. Separating drought effects from roof artifacts on ecosystem processes in a grassland drought experiment.

    PubMed

    Vogel, Anja; Fester, Thomas; Eisenhauer, Nico; Scherer-Lorenzen, Michael; Schmid, Bernhard; Weisser, Wolfgang W; Weigelt, Alexandra

    2013-01-01

    1: Given the predictions of increased drought probabilities under various climate change scenarios, there have been numerous experimental field studies simulating drought using transparent roofs in different ecosystems and regions. Such roofs may, however, have unknown side effects, called artifacts, on the measured variables potentially confounding the experimental results. A roofed control allows the quantification of potential artifacts, which is lacking in most experiments. 2: We conducted a drought experiment in experimental grasslands to study artifacts of transparent roofs and the resulting effects of artifacts on ecosystems relative to drought on three response variables (aboveground biomass, litter decomposition and plant metabolite profiles). We established three drought treatments, using (1) transparent roofs to exclude rainfall, (2) an unroofed control treatment receiving natural rainfall and (3) a roofed control, nested in the drought treatment but with rain water reapplied according to ambient conditions. 3: Roofs had a slight impact on air (+0.14°C during night) and soil temperatures (-0.45°C on warm days, +0.25°C on cold nights), while photosynthetically active radiation was decreased significantly (-16%). Aboveground plant community biomass was reduced in the drought treatment (-41%), but there was no significant difference between the roofed and unroofed control, i.e., there were no measurable roof artifact effects. 4: Compared to the unroofed control, litter decomposition was decreased significantly both in the drought treatment (-26%) and in the roofed control treatment (-18%), suggesting artifact effects of the transparent roofs. Moreover, aboveground metabolite profiles in the model plant species Medicago x varia were different from the unroofed control in both the drought and roofed control treatments, and roof artifact effects were of comparable magnitude as drought effects. 5: Our results stress the need for roofed control treatments

  20. Separating Drought Effects from Roof Artifacts on Ecosystem Processes in a Grassland Drought Experiment

    PubMed Central

    Vogel, Anja; Fester, Thomas; Eisenhauer, Nico; Scherer-Lorenzen, Michael; Schmid, Bernhard; Weisser, Wolfgang W.; Weigelt, Alexandra

    2013-01-01

    1 Given the predictions of increased drought probabilities under various climate change scenarios, there have been numerous experimental field studies simulating drought using transparent roofs in different ecosystems and regions. Such roofs may, however, have unknown side effects, called artifacts, on the measured variables potentially confounding the experimental results. A roofed control allows the quantification of potential artifacts, which is lacking in most experiments. 2 We conducted a drought experiment in experimental grasslands to study artifacts of transparent roofs and the resulting effects of artifacts on ecosystems relative to drought on three response variables (aboveground biomass, litter decomposition and plant metabolite profiles). We established three drought treatments, using (1) transparent roofs to exclude rainfall, (2) an unroofed control treatment receiving natural rainfall and (3) a roofed control, nested in the drought treatment but with rain water reapplied according to ambient conditions. 3 Roofs had a slight impact on air (+0.14°C during night) and soil temperatures (−0.45°C on warm days, +0.25°C on cold nights), while photosynthetically active radiation was decreased significantly (−16%). Aboveground plant community biomass was reduced in the drought treatment (−41%), but there was no significant difference between the roofed and unroofed control, i.e., there were no measurable roof artifact effects. 4 Compared to the unroofed control, litter decomposition was decreased significantly both in the drought treatment (−26%) and in the roofed control treatment (−18%), suggesting artifact effects of the transparent roofs. Moreover, aboveground metabolite profiles in the model plant species Medicago x varia were different from the unroofed control in both the drought and roofed control treatments, and roof artifact effects were of comparable magnitude as drought effects. 5 Our results stress the need for roofed control

  1. Glomalin-related soil protein in a Mediterranean ecosystem affected by a copper smelter and its contribution to Cu and Zn sequestration.

    PubMed

    Cornejo, Pablo; Meier, Sebastián; Borie, Gilda; Rillig, Matthias C; Borie, Fernando

    2008-11-15

    The amount of glomalin-related soil protein (GRSP), a glycoprotein produced by arbuscular mycorrhizal fungi (AMF), its contribution to the sequestering of Cu and Zn in the soil, and the microsite variation of other soil traits (pH, water-stable aggregates--[WSA], soil organic carbon--[SOC]) was studied in a semi-arid Mediterranean ecosystem near a copper smelter and affected by deposit of metal-rich particles since 1964. Rhizospheric (R) and non-rhizospheric (NR) soil of four representative plants (Argemone subfusiformis, Baccharis linearis, Oenothera affinis and Polypogon viridis) was analyzed. The results showed a strong variability in GRSP (6.6-36.8 mg g(-1)), Cu content (62-831 mg kg(-1) for the total Cu and 5.8-326 mg kg(-1) for the available Cu) and pH (4.2-5.5) in the different plant and rhizospheric zones analyzed. A strong relationship between the GRSP with the soil Cu and Zn contents was found (r=0.89 and 0.76 for Cu and Zn respectively, p<0.001). The GRSP-bound Cu ranged from 3.76 to 89.0 mg g(-1) soil and represents 1.44-27.5% of the total Cu content in soil. Moreover, the WSA reached 89% in P. viridis R. For this plant, the C contained in GRSP represented up to 89% of SOC, and this coincided with the most extreme conditions of soil degradation within the ecosystem (the highest content of heavy metals and low pH values). This study provides evidence on the role of the GRSP in Cu and Zn sequestration and suggests a highly efficient mechanism of AMF to mitigate stress leading to stabilization of soils highly polluted by mining activities. PMID:18762323

  2. 10 years of BAWLing into affective and aesthetic processes in reading: what are the echoes?

    PubMed

    Jacobs, Arthur M; Võ, Melissa L-H; Briesemeister, Benny B; Conrad, Markus; Hofmann, Markus J; Kuchinke, Lars; Lüdtke, Jana; Braun, Mario

    2015-01-01

    Reading is not only "cold" information processing, but involves affective and aesthetic processes that go far beyond what current models of word recognition, sentence processing, or text comprehension can explain. To investigate such "hot" reading processes, standardized instruments that quantify both psycholinguistic and emotional variables at the sublexical, lexical, inter-, and supralexical levels (e.g., phonological iconicity, word valence, arousal-span, or passage suspense) are necessary. One such instrument, the Berlin Affective Word List (BAWL) has been used in over 50 published studies demonstrating effects of lexical emotional variables on all relevant processing levels (experiential, behavioral, neuronal). In this paper, we first present new data from several BAWL studies. Together, these studies examine various views on affective effects in reading arising from dimensional (e.g., valence) and discrete emotion features (e.g., happiness), or embodied cognition features like smelling. Second, we extend our investigation of the complex issue of affective word processing to words characterized by a mixture of affects. These words entail positive and negative valence, and/or features making them beautiful or ugly. Finally, we discuss tentative neurocognitive models of affective word processing in the light of the present results, raising new issues for future studies.

  3. 10 years of BAWLing into affective and aesthetic processes in reading: what are the echoes?

    PubMed Central

    Jacobs, Arthur M.; Võ, Melissa L.-H.; Briesemeister, Benny B.; Conrad, Markus; Hofmann, Markus J.; Kuchinke, Lars; Lüdtke, Jana; Braun, Mario

    2015-01-01

    Reading is not only “cold” information processing, but involves affective and aesthetic processes that go far beyond what current models of word recognition, sentence processing, or text comprehension can explain. To investigate such “hot” reading processes, standardized instruments that quantify both psycholinguistic and emotional variables at the sublexical, lexical, inter-, and supralexical levels (e.g., phonological iconicity, word valence, arousal-span, or passage suspense) are necessary. One such instrument, the Berlin Affective Word List (BAWL) has been used in over 50 published studies demonstrating effects of lexical emotional variables on all relevant processing levels (experiential, behavioral, neuronal). In this paper, we first present new data from several BAWL studies. Together, these studies examine various views on affective effects in reading arising from dimensional (e.g., valence) and discrete emotion features (e.g., happiness), or embodied cognition features like smelling. Second, we extend our investigation of the complex issue of affective word processing to words characterized by a mixture of affects. These words entail positive and negative valence, and/or features making them beautiful or ugly. Finally, we discuss tentative neurocognitive models of affective word processing in the light of the present results, raising new issues for future studies. PMID:26089808

  4. Soil enzyme inhibition by condensed litter tannins may drive ecosystem structure and processes: the case of Kalmia angustifolia.

    PubMed

    Joanisse, G D; Bradley, R L; Preston, C M; Munson, A D

    2007-01-01

    Kalmia angustifolia is an ericaceous shrub that can rapidly spread on recently harvested boreal forest sites, causing a slow-down in soil nutrient cycling and reduced growth of spruce seedlings. It has been hypothesized that tannins released from Kalmia litter suppress soil enzyme activity, and are thus important in controlling ecosystem structure and processes. Here the effects of different concentrations of tannins extracted from both Kalmia and black spruce (Picea mariana) foliage were tested on enzyme activities of soil extracts. Then the effects of various Kalmia-black spruce litter mixtures on soil enzyme activity were investigated. Lastly, the correlation between Kalmia cover in the field and soil enzyme activity was measured. Both tannin types suppressed beta-glucosidase and acid phosphatase activities, and the magnitude of these effects was concentration-dependent. beta-glucosidase and amidase activity decreased linearly with an increasing Kalmia : spruce litter ratio added to soil. A field survey of 24 sites revealed a negative relationship between percentage Kalmia cover and beta-glucosidase activity. Collectively, results of the three experiments converge to support the claim that enzyme inhibition by litter tannins has evolved as an important mechanism controlling ecosystem processes and structure following Kalmia invasion on recently disturbed forest sites.

  5. Ecosystem Processes at the Watershed Scale: Stability and Resilience of Catchment Spatial Structure and Function to Disturbance

    NASA Astrophysics Data System (ADS)

    Baron, J.; Mast, A.; Clow, D. W.; Wetherbee, G. A.

    2014-12-01

    Ecohydrological systems evolve spontaneously in response to geologic, hydroclimate and biodiversity drivers. The stability and resilience of these systems to multiple disturbances can be addressed over specific temporal extents, potentially embedded within long term transience in response to geologic or climate change. The limits of ecohydrological resilience of system state in terms of vegetation canopy and soil catenae and the space/time distribution of water, carbon and nutrient cycling is determined by a set of critical feedbacks and potential substitutions of plant functional forms in response to disturbance. The ability of forest systems to return to states functionally similar to states prior to major disturbance, or combinations of multiple disturbances, is a critical question given increasing hydroclimate extremes, biological invasions, and human disturbance. Over the past century, forest landscape ecological patterns appear to have the ability to recover from significant disturbance and re-establish similar hydrological and ecological function in humid, biodiverse regions such as the southern Appalachians, and potentially drier forest ecosystems. Understanding and prediction of past and future long term dynamics requires explicit representation of spatial and temporal feedbacks and dependencies between hydrological, ecosystem and geomorphic processes, and the spatial pattern of species or plant functional type (PFT). Comprehensive models of watershed ecohydrological resilience requires careful balance between the level of process and parameter detail between the interacting components, relative to the structure, organization, space and time scales of the landscape.

  6. Ecosystem Processes at the Watershed Scale: Stability and Resilience of Catchment Spatial Structure and Function to Disturbance

    NASA Astrophysics Data System (ADS)

    Band, L. E.

    2015-12-01

    Ecohydrological systems evolve spontaneously in response to geologic, hydroclimate and biodiversity drivers. The stability and resilience of these systems to multiple disturbances can be addressed over specific temporal extents, potentially embedded within long term transience in response to geologic or climate change. The limits of ecohydrological resilience of system state in terms of vegetation canopy and soil catenae and the space/time distribution of water, carbon and nutrient cycling is determined by a set of critical feedbacks and potential substitutions of plant functional forms in response to disturbance. The ability of forest systems to return to states functionally similar to states prior to major disturbance, or combinations of multiple disturbances, is a critical question given increasing hydroclimate extremes, biological invasions, and human disturbance. Over the past century, forest landscape ecological patterns appear to have the ability to recover from significant disturbance and re-establish similar hydrological and ecological function in humid, biodiverse regions such as the southern Appalachians, and potentially drier forest ecosystems. Understanding and prediction of past and future long term dynamics requires explicit representation of spatial and temporal feedbacks and dependencies between hydrological, ecosystem and geomorphic processes, and the spatial pattern of species or plant functional type (PFT). Comprehensive models of watershed ecohydrological resilience requires careful balance between the level of process and parameter detail between the interacting components, relative to the structure, organization, space and time scales of the landscape.

  7. Introduction: SIPEX-2: A study of sea-ice physical, biogeochemical and ecosystem processes off East Antarctica during spring 2012

    NASA Astrophysics Data System (ADS)

    Meiners, Klaus M.; Golden, Ken M.; Heil, Petra; Lieser, Jan L.; Massom, Rob; Meyer, Bettina; Williams, Guy D.

    2016-09-01

    This editorial introduces a suite of articles resulting from the second Sea Ice Physics and Ecosystems eXperiment (SIPEX-2) voyage by presenting some background information on the study area and Antarctic sea-ice conditions, and summarising the key findings from the project. Using the Australian icebreaker RV Aurora Australis, SIPEX-2 was conducted in the area between 115-125°E and 62-66°S off East Antarctica during September to November 2012. This region had been sampled during two previous experiments, i.e. ARISE in 2003 (Massom et al., 2006a) and SIPEX in 2007 (Worby et al., 2011a). The 2012 voyage combined traditional and newly developed sampling methods with satellite and other data to measure sea-ice physical properties and processes on large scales, which provided context for biogeochemical and ecological case studies. The specific goals of the SIPEX-2 project were to: (i) measure the spatial variability in sea-ice and snow-cover properties over small- to regional-length scales; (ii) improve understanding of sea-ice kinematic processes; and (iii) advance knowledge of the links between sea-ice physical characteristics, sea-ice biogeochemical cycling and ice-associated food-web dynamics. Our field-based activities were designed to inform modelling approaches and to improve our capability to assess impacts of predicted changes in Antarctic sea ice on Southern Ocean biogeochemical cycles and ecosystem function.

  8. Key factors, Soil N Processes, and nitrite accumulation affecting nitrous oxide emissions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A better understanding of the key factors affecting nitrous oxide (N2O) emission and potential mitigation strategies is essential for sustainable agriculture. The objective of this study was to examine the important factors affecting N2O emissions, soil processes involved, and potential mitigation s...

  9. Searching for Judy: How Small Mysteries Affect Narrative Processes and Memory

    ERIC Educational Resources Information Center

    Love, Jessica; McKoon, Gail; Gerrig, Richard J.

    2010-01-01

    Current theories of text processing say little about how authors' narrative choices, including the introduction of small mysteries, can affect readers' narrative experiences. Gerrig, Love, and McKoon (2009) provided evidence that 1 type of small mystery--a character introduced without information linking him or her to the story--affects readers'…

  10. Factors affecting the transfer of radiocaesium from soil to roe deer in forest ecosystems of southern Germany.

    PubMed

    Kiefer, P; Pröhl, G; Müller, H; Lindner, G; Drissner, J; Zibold, G

    1996-11-29

    soil layers and the biological processes therein with respect to the bioavailability of caesium. On the two sites, the values at the lower boundary are more typical for animals that have access to agricultural areas, whereas the higher values were observed in autumn and for animals grazing distant from agricultural areas.

  11. Ecohydrological optimization of pattern and processes in water-limited ecosystems: A trade-off-based hypothesis

    NASA Astrophysics Data System (ADS)

    Caylor, Kelly K.; Scanlon, Todd M.; Rodriguez-Iturbe, Ignacio

    2009-08-01

    The complex interactions between plants, soils, and climates in semiarid ecosystems make it difficult to define specific ecohydrological optimization mechanisms that underlie observed spatiotemporal patterns of vegetation structure. There remains a clear need to develop conceptual models that are capable of interpreting and predicting spatial pattern formation in savannas (and similar dry woodland ecosystems), as well as metrics for assessing optimization or organization of patterns, as one scales from individual canopies to landscapes and beyond. In this article, we propose a unifying hypothesis regarding ecohydrological optimization of pattern and processes, namely, that vegetation patterns in water-limited environments are constrained in their ability to maximize water use by a need to simultaneously minimize water stress. We use this trade-off-based hypothesis to infer the function of dryland ecosystems under a wide range of scales and applications. Specifically, we examine spatial and temporal aspects of ecohydrological organization of vegetation patterns for three different cases: (1) patterns of regional-scale temporal organization across a regional climate gradient, (2) patterns of landscape-scale spatial organization within a semiarid drainage basin, and (3) patterns of individual-scale structural organization across varying soil textures. Although the insight gained from each of these examples is derived from specific modeling approaches, each of which contains its own unique set of assumptions and limitations, they are unified by our proposed ecohydrological trade-off approach that simultaneously considers both plant water deficit and plant water use as a diagnostic tool for assessing vegetation patterns in water-limited environments. It is our hope that the ongoing development of coupled ecological and hydrological models capable of assessing a diversity of interactions between plants, soils, and climates will lead to the emergence of more generalized

  12. How do how internal and external processes affect the behaviors of coupled marsh mudflat systems; infill, stabilize, retreat, or drown?

    NASA Astrophysics Data System (ADS)

    Carr, J. A.; Mariotti, G.; Wiberg, P.; Fagherazzi, S.; McGlathery, K.

    2013-12-01

    Intertidal coastal environments are prone to changes induced by sea level rise, increases in storminess, and anthropogenic disturbances. It is unclear how changes in external drivers may affect the dynamics of low energy coastal environments because their response is non-linear, and characterized by many thresholds and discontinuities. As such, process-based modeling of the ecogeomorphic processes underlying the dynamics of these ecosystems is useful, not only to predict their change through time, but also to generate new hypotheses and research questions. Here, a three-point dynamic model was developed to investigate how internal and external processes affect the behavior of coupled marsh mudflat systems. The model directly incorporates ecogeomorphological feedbacks between wind waves, salt marsh vegetation, allochthonous sediment loading, tidal flat vegetation and sea level rise. The model was applied to examine potential trajectories of salt marshes on the Eastern seaboard of the United States, including those in the Plum Island Ecosystems (PIE), Virginia Coast Reserve (VCR) and Georgia Coastal Ecosystems (GCE) long term ecological research (LTER) sites. While these sites are undergoing similar rates of relative sea level rise (RSLR), they have distinct differences in site specific environmental drivers including tides, wind waves, allochthonous sediment supply and the presence or absence of seagrass. These differences lead to the emergence of altered behaviors in the coupled salt marsh-tidal flat system. For marsh systems without seagrass or significant riverine sediment supply, conditions similar to those at PIE, results indicated that horizontal and vertical marsh evolution respond in opposing ways to wave induced processes. Marsh horizontal retreat is triggered by large mudflats and strong winds, whereas small mudflats and weak winds reduce the sediment supply to the salt marsh, decreasing its capability to keep pace with sea level rise. Marsh expansion and

  13. Modeling Elevation and Aspect Controls on Emerging Ecohydrologic Processes and Ecosystem Patterns Using the Component-based Landlab Framework

    NASA Astrophysics Data System (ADS)

    Nudurupati, S. S.; Istanbulluoglu, E.; Adams, J. M.; Hobley, D. E. J.; Gasparini, N. M.; Tucker, G. E.; Hutton, E. W. H.

    2014-12-01

    Topography plays a commanding role on the organization of ecohydrologic processes and resulting vegetation patterns. In southwestern United States, climate conditions lead to terrain aspect- and elevation-controlled ecosystems, with mesic north-facing and xeric south-facing vegetation types; and changes in biodiversity as a function of elevation from shrublands in low desert elevations, to mixed grass/shrublands in mid elevations, and forests at high elevations and ridge tops. These observed patterns have been attributed to differences in topography-mediated local soil moisture availability, micro-climatology, and life history processes of plants that control chances of plant establishment and survival. While ecohydrologic models represent local vegetation dynamics in sufficient detail up to sub-hourly time scales, plant life history and competition for space and resources has not been adequately represented in models. In this study we develop an ecohydrologic cellular automata model within the Landlab component-based modeling framework. This model couples local vegetation dynamics (biomass production, death) and plant establishment and competition processes for resources and space. This model is used to study the vegetation organization in a semiarid New Mexico catchment where elevation and hillslope aspect play a defining role on plant types. Processes that lead to observed plant types across the landscape are examined by initializing the domain with randomly assigned plant types and systematically changing model parameters that couple plant response with soil moisture dynamics. Climate perturbation experiments are conducted to examine the plant response in space and time. Understanding the inherently transient ecohydrologic systems is critical to improve predictions of climate change impacts on ecosystems.

  14. Hotter Drought, Disturbance Process Thresholds, and Reorganization of Forest Ecosystems and Watersheds in the Southwestern USA, and Beyond

    NASA Astrophysics Data System (ADS)

    Allen, C. D.

    2015-12-01

    Extensive high-severity wildfires and drought-induced tree mortality (including drought-and-heat-related insect pest outbreaks), along with associated major alterations of watershed conditions and hydrological processes, have intensified over the last two decades in Southwest USA forests and woodlands—on a scale unseen regionally since at least pre-1900, and quite possibly not for millennia, based on diverse lines of paleo-ecological and geomorphic evidence. Historical land-use patterns, decadal-scale climate variability (e.g., drought linked to the Pacific Decadal Oscillation), and warming temperatures in recent decades (resulting in "hotter drought" conditions) have been important interactive drivers of observed nonlinear threshold changes in these forest disturbance processes. In response, Southwest forest landscapes have been rapidly transitioning toward more open and drought-tolerant ecosystems, with altered ecohydrological patterns. If regional temperatures increase as projected by climate models, multiple lines of evidence (experiments, observations, empirical models, process models) suggest that Southwest drought stress after ca. 2050 will increasingly exceed that of the most severe droughts in the past 1,000 years, putting current historical forests at grave risk—in particular the tallest (& often the oldest) trees and forests. These findings point toward the emergence of increasingly novel vegetation patterns over the course of this century. Forests globally exhibit great diversity in environmental drivers, histories, dominant ecological patterns and processes, biodiversity, etc., which are expected to produce diverse forest responses (and levels of resilience) to projected global changes in climate and human uses this century. Even given this planetary diversity of forests and expected global change responses, the observed reorganization of forests underway in the Southwest USA - driven by the convergence of changes in land use patterns, disturbance

  15. Influences of physical processes on the ecosystem in Jiaozhou Bay: A coupled physical and biological model experiment

    NASA Astrophysics Data System (ADS)

    Chen, Changsheng; Ji, Rubao; Zheng, Lianyuan; Zhu, Mingyuan; Rawson, Mac

    1999-12-01

    In this paper we have used a three-dimensional coupled physical and biological model to examine the marine ecosystem of Jiaozhou Bay. Physical processes included (1) the M2 tide, (2) river discharges, and (3) winds. The biological model described a simple, phosphorous-based, lower trophic food web system. The model results showed that tidal mixing had a direct impact on temporal and spatial distributions of nutrients and phytoplankton as well as on shellfish aquaculture. Nutrients and phytoplankton were well mixed vertically by tidal motion. Their concentrations were highest around northwestern and northern regions of the bay near river sources and decreased with water depth from the inner bay to the outer bay. A phytoplankton bloom can occur around the northwestern coast due to the "accumulation" of nutrients under southeasterly wind conditions. The flux analysis suggests that in summer the nutrients in Jiaozhou Bay was directly supplied and maintained by physical processes, but the temporal variation of phytoplankton was controlled dominantly by biological processes associated with nutrient uptake, grazing by zooplankton, and consumption by shellfish. Shellfish aquaculture can modify the bay-scale balance of the ecosystem in Jiaozhou Bay. The loss of phytoplankton in shellfish aquaculture sites tended to be compensated by advection and diffusion from the surrounding waters. A large consumption of phytoplankton by shellfish can cause a net flux of phytoplankton from the Yellow Sea to Jiaozhou Bay, although there was a net nutrient flux flowing out of the bay. The physical mechanism for the water exchange between Jiaozhou Bay and the Yellow Sea was controlled mainly by a chaotic process associated with nonlinear interactions between oscillating tidal currents and double residual eddies.

  16. Inferring differential evolutionary processes of plant persistence traits in Northern Hemisphere Mediterranean fire-prone ecosystems

    USGS Publications Warehouse

    Pausas, J.G.; Keeley, J.E.; Verdu, M.

    2006-01-01

    1 Resprouting capacity (R) and propagule-persistence (P) are traits that are often considered to have evolved where there are predictable crown fires. Because several indicators suggest a stronger selective pressure for such traits in California than in the Mediterranean Basin, we hypothesize that plant species should have evolved to become R+ and P+ more frequently in California than in the Mediterranean Basin. 2 To test this hypothesis we studied the phylogenetic association between R and P states in both California and the Mediterranean Basin using published molecular phylogenies. 3 The results suggest that R and P evolved differently in the two regions. The occurrence of the states differs significantly between regions for trait P, but not for trait R. The different patterns (towards R+ and P+ in California and towards R+ and P- in the Mediterranean Basin) are reflected in the higher abundance and the wider taxonomic distribution of species with both persistence traits (R+P+ species) in California. 4 The differential acquisition of fire persistence mechanisms at the propagule level (P+) supports the idea that fire selective pressures has been higher in California than in the Mediterranean Basin. 5 Our comparative phylogenetic-informed analysis contributes to an understanding of the differential role of the Quaternary climate in determining fire persistence traits in different Mediterranean-type ecosystems and, thus, to the debate on the evolutionary convergence of traits. ?? 2006 British Ecological Society.

  17. Disturbance Distance: Using a process based ecosystem model to estimate and map potential thresholds in disturbance rates that would give rise to fundamentally altered ecosystems

    NASA Astrophysics Data System (ADS)

    Dolan, K. A.; Hurtt, G. C.; Fisk, J.; Flanagan, S.; LePage, Y.; Sahajpal, R.

    2014-12-01

    Disturbance plays a critical role in shaping the structure and function of forested ecosystems as well as the ecosystem services they provide, including but not limited to: carbon storage, biodiversity habitat, water quality and flow, and land atmosphere exchanges of energy and water. As recent studies highlight novel disturbance regimes resulting from pollution, invasive pests and climate change, there is a need to include these alterations in predictions of future forest function and structure. The Ecosystem Demography (ED) model is a mechanistic model of forest ecosystem dynamics in which individual-based forest dynamics can be efficiently implemented over regional to global scales due to advanced scaling methods. We utilize ED to characterize the sensitivity of potential vegetation structure and function to changes in rates of density independent mortality. Disturbance rate within ED can either be altered directly or through the development of sub-models. Disturbance sub-models in ED currently include fire, land use and hurricanes. We use a tiered approach to understand the sensitivity of North American ecosystems to changes in background density independent mortality. Our first analyses were conducted at half-degree spatial resolution with a constant rate of disturbance in space and time, which was altered between runs. Annual climate was held constant at the site level and the land use and fire sub-models were turned off. Results showed an ~ 30% increase in non-forest area across the US when disturbance rates were changed from 0.6% a year to 1.2% a year and a more than 3.5 fold increase in non-forest area when disturbance rates doubled again from 1.2% to 2.4%. Continued runs altered natural background disturbance rates with the existing fire and hurricane sub models turned on as well as historic and future land use. By quantify differences between model outputs that characterize ecosystem structure and function related to the carbon cycle across the US, we

  18. The Impact of Affect on Out-Group Judgments Depends on Dominant Information-Processing Styles: Evidence From Incidental and Integral Affect Paradigms.

    PubMed

    Isbell, Linda M; Lair, Elicia C; Rovenpor, Daniel R

    2016-04-01

    Two studies tested the affect-as-cognitive-feedback model, in which positive and negative affective states are not uniquely associated with particular processing styles, but rather serve as feedback about currently accessible processing styles. The studies extend existing work by investigating (a) both incidental and integral affect, (b) out-group judgments, and (c) downstream consequences. We manipulated processing styles and either incidental (Study 1) or integral (Study 2) affect and measured perceptions of out-group homogeneity. Positive (relative to negative) affect increased out-group homogeneity judgments when global processing was primed, but under local priming, the effect reversed (Studies 1 and 2). A similar interactive effect emerged on attributions, which had downstream consequences for behavioral intentions (Study 2). These results demonstrate that both incidental and integral affect do not directly produce specific processing styles, but rather influence thinking by providing feedback about currently accessible processing styles. PMID:26984013

  19. Interaction of the methane cycle and processes in wetland ecosystems in a climate model of intermediate complexity

    NASA Astrophysics Data System (ADS)

    Eliseev, A. V.; Mokhov, I. I.; Arzhanov, M. M.; Demchenko, P. F.; Denisov, S. N.

    2008-04-01

    The climate model of the Institute of Atmospheric Physics of the Russian Academy of Sciences (IAP RAS CM) has been supplemented with a module of soil thermal physics and the methane cycle, which takes into account the response of methane emissions from wetland ecosystems to climate changes. Methane emissions are allowed only from unfrozen top layers of the soil, with an additional constraint in the depth of the simulated layer. All wetland ecosystems are assumed to be water-saturated. The molar amount of the methane oxidized in the atmosphere is added to the simulated atmospheric concentration of CO2. A control preindustrial experiment and a series of numerical experiments for the 17th-21st centuries were conducted with the model forced by greenhouse gases and tropospheric sulfate aerosols. It is shown that the IAP RAS CM generally reproduces preindustrial and current characteristics of both seasonal thawing/freezing of the soil and the methane cycle. During global warming in the 21st century, the permafrost area is reduced by four million square kilometers. By the end of the 21st century, methane emissions from wetland ecosystems amount to 130-140 Mt CH4/year for the preindustrial and current period increase to 170-200 MtCH4/year. In the aggressive anthropogenic forcing scenario A2, the atmospheric methane concentration grows steadily to ≈3900 ppb. In more moderate scenarios A1B and B1, the methane concentration increases until the mid-21st century, reaching ≈2100-2400 ppb, and then decreases. Methane oxidation in air results in a slight additional growth of the atmospheric concentration of carbon dioxide. Allowance for the interaction between processes in wetland ecosystems and the methane cycle in the IAP RAS CM leads to an additional atmospheric methane increase of 10-20% depending on the anthropogenic forcing scenario and the time. The causes of this additional increase are the temperature dependence of integral methane production and the longer duration

  20. Processes of community development and responses of ecosystems to climate change. Progress report, September 28, 1988--September 27, 1989

    SciTech Connect

    Redente, E.F.

    1989-05-26

    Our studies focus on attempting to understand the role of decomposer-primary producer linkages in successional dynamics. We are testing a series of hypotheses that relate changes in plant species composition during succession to changes in activity and structure of the soil microfloral and faunal community, dynamics of soil organic matter, and availability of soil nutrients. As these successional patterns are identified, they are being applied to understanding specific processes and mechanics involved in ecosystem development during recovery from moderate and severe disturbances. These findings are then being used in conjunction with simulation models to assess potential effects of climate change on ecosystems. Our research involves field studies in northwestern Colorado and southeastern Washington, laboratory studies, and simulation modeling. Ongoing projects include studies of response patterns of primary producer and soil microbial communities to nutrient additions (N, P, and sucrose), the function of mycorrhizal fungi in plant community development, and the dynamics of litter decomposition under semiarid conditions. New studies are being implemented to investigate the significance of nutrient transfers from VAM fungi to plants and plant-root exudate interactions, and to relate this to understanding their roles in succession.

  1. Information-Processing and Perceptions of Control: How Attribution Style Affects Task-Relevant Processing

    ERIC Educational Resources Information Center

    Yeigh, Tony

    2007-01-01

    This study investigated the effects of perceived controllability on information processing within Weiner's (1985, 1986) attributional model of learning. Attributional style was used to identify trait patterns of controllability for 37 university students. Task-relevant feedback on an information-processing task was then manipulated to test for…

  2. The “Musical Emotional Bursts”: a validated set of musical affect bursts to investigate auditory affective processing

    PubMed Central

    Paquette, Sébastien; Peretz, Isabelle; Belin, Pascal

    2013-01-01

    The Musical Emotional Bursts (MEB) consist of 80 brief musical executions expressing basic emotional states (happiness, sadness and fear) and neutrality. These musical bursts were designed to be the musical analog of the Montreal Affective Voices (MAV)—a set of brief non-verbal affective vocalizations portraying different basic emotions. The MEB consist of short (mean duration: 1.6 s) improvisations on a given emotion or of imitations of a given MAV stimulus, played on a violin (10 stimuli × 4 [3 emotions + neutral]), or a clarinet (10 stimuli × 4 [3 emotions + neutral]). The MEB arguably represent a primitive form of music emotional expression, just like the MAV represent a primitive form of vocal, non-linguistic emotional expression. To create the MEB, stimuli were recorded from 10 violinists and 10 clarinetists, and then evaluated by 60 participants. Participants evaluated 240 stimuli [30 stimuli × 4 (3 emotions + neutral) × 2 instruments] by performing either a forced-choice emotion categorization task, a valence rating task or an arousal rating task (20 subjects per task); 40 MAVs were also used in the same session with similar task instructions. Recognition accuracy of emotional categories expressed by the MEB (n:80) was lower than for the MAVs but still very high with an average percent correct recognition score of 80.4%. Highest recognition accuracies were obtained for happy clarinet (92.0%) and fearful or sad violin (88.0% each) MEB stimuli. The MEB can be used to compare the cerebral processing of emotional expressions in music and vocal communication, or used for testing affective perception in patients with communication problems. PMID:23964255

  3. Combined use of isotopic and hydrometric data to conceptualize ecohydrological processes in a high-elevation tropical ecosystem

    USGS Publications Warehouse

    Mosquera, Giovanny M; Celleri, Rolando; Lazo, Patricio X; Vache, Kellie B; Perakis, Steven; Crespo, Patricio

    2016-01-01

    Few high-elevation tropical catchments worldwide are gauged and even fewer are studied using combined hydrometric and isotopic data. Consequently, we lack information needed to understand processes governing rainfall-runoff dynamics and to predict their influence on downstream ecosystem functioning. To address this need, we present a combination of hydrometric and water stable isotopic observations in the wet Andean páramo ecosystem of the Zhurucay Ecohydrological Observatory (7.53 km2). The catchment is located in the Andes of south Ecuador between 3400 and 3900 m a.s.l. Water samples for stable isotopic analysis were collected during 2 years (May 2011 – May 2013), while rainfall and runoff measurements were continuously recorded since late 2010. The isotopic data reveal that Andosol soils predominantly situated on hillslopes drain laterally to Histosols (Andean páramo wetlands) mainly located at the valley bottom. Histosols, in turn, feed water to creeks and small rivers throughout the year, establishing hydrologic connectivity between wetlands and the drainage network. Runoff is primarily comprised of pre-event water stored in the Histosols, which is replenished by rainfall that infiltrates through the Andosols. Contributions from the mineral horizon and the top of the fractured bedrock are small and only seem to influence discharge in small catchments during low flow generation (non-exceedance flows < Q35). Variations in source contributions are controlled by antecedent soil moisture, rainfall intensity, and duration of rainy periods. Saturated hydraulic conductivity of the soils, higher than the year-round low precipitation intensity, indicates that Hortonian overland flow rarely occurs during high intensity precipitation events. Deep groundwater contributions to discharge seem to be minimal. These results suggest that, in this high-elevation tropical ecosystem: 1) subsurface flow is a dominant hydrological process and 2) (Histosols) wetlands are the major

  4. How Does Tele-Mental Health Affect Group Therapy Process? Secondary Analysis of a Noninferiority Trial

    ERIC Educational Resources Information Center

    Greene, Carolyn J.; Morland, Leslie A.; Macdonald, Alexandra; Frueh, B. Christopher; Grubbs, Kathleen M.; Rosen, Craig S.

    2010-01-01

    Objective: Video teleconferencing (VTC) is used for mental health treatment delivery to geographically remote, underserved populations. However, few studies have examined how VTC affects individual or group psychotherapy processes. This study compares process variables such as therapeutic alliance and attrition among participants receiving anger…

  5. Ecological and Dynamical Study of the Creative Process and Affects of Scientific Students Working in Groups

    ERIC Educational Resources Information Center

    Peilloux, Aurélien; Botella, Marion

    2016-01-01

    Although creativity has drawn the attention of researchers during the past century, collaborative processes have barely been investigated. In this article, the collective dimension of a creative process is investigated, based on a dynamic and ecological approach that includes an affective component. "Dynamic" means that the creative…

  6. The Mechanism of Valence-Space Metaphors: ERP Evidence for Affective Word Processing

    PubMed Central

    Xie, Jiushu; Wang, Ruiming; Chang, Song

    2014-01-01

    Embodied cognition contends that the representation and processing of concepts involve perceptual, somatosensory, motoric, and other physical re-experiencing information. In this view, affective concepts are also grounded in physical information. For instance, people often say “feeling down” or “cheer up” in daily life. These phrases use spatial information to understand affective concepts. This process is referred to as valence-space metaphor. Valence-space metaphors refer to the employment of spatial information (lower/higher space) to elaborate affective concepts (negative/positive concepts). Previous studies have demonstrated that processing affective words affects performance on a spatial detection task. However, the mechanism(s) behind this effect remain unclear. In the current study, we hypothesized that processing affective words might produce spatial information. Consequently, spatial information would affect the following spatial cue detection/discrimination task. In Experiment 1, participants were asked to remember an affective word. Then, they completed a spatial cue detection task while event-related potentials were recorded. The results indicated that the top cues induced enhanced amplitude of P200 component while participants kept positive words relative to negative words in mind. On the contrary, the bottom cues induced enhanced P200 amplitudes while participants kept negative words relative to positive words in mind. In Experiment 2, we conducted a behavioral experiment that employed a similar paradigm to Experiment 1, but used arrows instead of dots to test the attentional nature of the valence-space metaphor. We found a similar facilitation effect as found in Experiment 1. Positive words facilitated the discrimination of upper arrows, whereas negative words facilitated the discrimination of lower arrows. In summary, affective words might activate spatial information and cause participants to allocate their attention to corresponding

  7. The mechanism of valence-space metaphors: ERP evidence for affective word processing.

    PubMed

    Xie, Jiushu; Wang, Ruiming; Chang, Song

    2014-01-01

    Embodied cognition contends that the representation and processing of concepts involve perceptual, somatosensory, motoric, and other physical re-experiencing information. In this view, affective concepts are also grounded in physical information. For instance, people often say "feeling down" or "cheer up" in daily life. These phrases use spatial information to understand affective concepts. This process is referred to as valence-space metaphor. Valence-space metaphors refer to the employment of spatial information (lower/higher space) to elaborate affective concepts (negative/positive concepts). Previous studies have demonstrated that processing affective words affects performance on a spatial detection task. However, the mechanism(s) behind this effect remain unclear. In the current study, we hypothesized that processing affective words might produce spatial information. Consequently, spatial information would affect the following spatial cue detection/discrimination task. In Experiment 1, participants were asked to remember an affective word. Then, they completed a spatial cue detection task while event-related potentials were recorded. The results indicated that the top cues induced enhanced amplitude of P200 component while participants kept positive words relative to negative words in mind. On the contrary, the bottom cues induced enhanced P200 amplitudes while participants kept negative words relative to positive words in mind. In Experiment 2, we conducted a behavioral experiment that employed a similar paradigm to Experiment 1, but used arrows instead of dots to test the attentional nature of the valence-space metaphor. We found a similar facilitation effect as found in Experiment 1. Positive words facilitated the discrimination of upper arrows, whereas negative words facilitated the discrimination of lower arrows. In summary, affective words might activate spatial information and cause participants to allocate their attention to corresponding locations

  8. Changing vegetation self organisation affecting eco-hydrological and geomorphological processes under invasion of blue bush in SE South Africa

    NASA Astrophysics Data System (ADS)

    Cammeraat, L. H.; Kakembo, V.

    2012-04-01

    In southeastern South Africa sub-humid grasslands on abandoned soils are spontaneously being invaded by the exotic shrub Pteronia incana (Blue bush) originating from the semi-arid and arid Karoo region. This results eventually in soil loss and rill and gully erosion and consequently loss in agricultural production affecting the local rural economy. Degradation of soils is occurring following replacement of grassland by unpalatable shrubs and altering the spatial organization of the vegetation. This in consequence is changing the eco-hydrological response of the hillslopes leading to a dramatic increase of runoff and erosion. However the reason for this spontaneous vegetation replacement is not clear. Various explanations have been proposed and discussed such as overgrazing, vegetation cover and rainfall, drought or climatic change or exposition. The study presented aims at quantifying the observed changes in the plant and bare spot patterns and which may help us unraveling vegetation self organisation processes in relation to environmental disturbances. We analyzed high resolution low altitude images of vegetation patterns in combination with high resolution digital terrain model analysis. We applied this procedure for different patterns reflecting a time series covering the observed changing patterns. These reflect changing interactions between the (re-) organization of the plant patterns during the bushy invasion and incorporated the interaction between vegetation, water redistribution and soil properties. By doing so we may be able to unravel critical processes as indicated by changes in vegetation patterns that might enable us to mitigate degradation of dryland ecosystems.

  9. Ecological issues related to N deposition to natural ecosystems: research needs.

    PubMed

    Adams, Mary Beth

    2003-06-01

    There has and continues to be concern about the effects of elevated nitrogen (N) deposition on natural ecosystems. In this paper, research on natural ecosystems, including wetlands, heathlands, grasslands, steppe, naturally regenerated forests and deserts, is evaluated to determine what is known about nitrogen cycling in these ecosystems, the effects of elevated nitrogen on them and to identify research gaps. Aquatic ecosystems are not included in this review, except as they are part of the larger ecosystem. Research needs fall into several categories: (1) improved understanding and quantification of the N cycle, particularly relatively unstudied processes such as dry deposition, N fixation and decomposition/mineralization; (2) carbon cycling as affected by increased N deposition; (3) effects on arid ecosystems and other "neglected" ecosystems; (4) effects on complex ecosystems and interactions with other pollutants; (5) indicators and assessment tools for natural ecosystems. PMID:12676207

  10. Ecological issues related to N deposition to natural ecosystems: research needs.

    PubMed

    Adams, Mary Beth

    2003-06-01

    There has and continues to be concern about the effects of elevated nitrogen (N) deposition on natural ecosystems. In this paper, research on natural ecosystems, including wetlands, heathlands, grasslands, steppe, naturally regenerated forests and deserts, is evaluated to determine what is known about nitrogen cycling in these ecosystems, the effects of elevated nitrogen on them and to identify research gaps. Aquatic ecosystems are not included in this review, except as they are part of the larger ecosystem. Research needs fall into several categories: (1) improved understanding and quantification of the N cycle, particularly relatively unstudied processes such as dry deposition, N fixation and decomposition/mineralization; (2) carbon cycling as affected by increased N deposition; (3) effects on arid ecosystems and other "neglected" ecosystems; (4) effects on complex ecosystems and interactions with other pollutants; (5) indicators and assessment tools for natural ecosystems.

  11. Impacts of soil faunal community composition on model grassland ecosystems.

    PubMed

    Bradford, M A; Jones, T H; Bardgett, R D; Black, H I J; Boag, B; Bonkowski, M; Cook, R; Eggers, T; Gange, A C; Grayston, S J; Kandeler, E; McCaig, A E; Newington, J E; Prosser, J I; Setälä, H; Staddon, P L; Tordoff, G M; Tscherko, D; Lawton, J H

    2002-10-18

    Human impacts, including global change, may alter the composition of soil faunal communities, but consequences for ecosystem functioning are poorly understood. We constructed model grassland systems in the Ecotron controlled environment facility and manipulated soil community composition through assemblages of different animal body sizes. Plant community composition, microbial and root biomass, decomposition rate, and mycorrhizal colonization were all markedly affected. However, two key ecosystem processes, aboveground net primary productivity and net ecosystem productivity, were surprisingly resistant to these changes. We hypothesize that positive and negative faunal-mediated effects in soil communities cancel each other out, causing no net ecosystem effects.

  12. Process coupling and control over the response of net ecosystem CO2 exchange to climate variability and insect disturbance in subalpine forests of the Western US

    NASA Astrophysics Data System (ADS)

    Monson, R. K.; Moore, D. J.; Trahan, N. A.; Scott-Denton, L.; Burns, S. P.; Hu, J.; Bowling, D. R.

    2011-12-01

    Following ten years of studies in subalpine forest ecosystems of the Western US, we have concluded that the tight coupling between gross primary productivity (GPP) and the autotrophic component of soil respiration (Ra) drives responses of net ecosystem CO2 exchange (NEE) to climate variability and insect disturbance. This insight has been gained through long-term eddy flux observations, manipulative plot experiments, analyses of dynamics in the stable isotope compositions of CO2 and H2O, and chamber gas-exchange measurements. Using past observations from these studies, we deployed model-data assimilation techniques and forecast weather/climate modeling to estimate how the coupling between GPP and Ra is likely to affect future (Year 2100) dynamics in NEE. The amount of winter snow and its melting dynamics in the spring represents the dominant control over interannual variation in GPP. Using the SIPNET ecosystem process model, combined with knowledge about the stable isotope content of different water sources, we estimated that approximately 75% of growing season GPP is coupled to the use of snowmelt water, whereas approximately 25% is coupled to summer rain. The tight coupling between GPP and winter snow pack drives a similar tight coupling between soil respiration (Rs) and winter snow pack. Manipulation of snow pack on forest plots has shown that Rs increases with increased snow pack, and this effect disappears when trees are girdled, which stops the transfer of GPP to roots and the soil rhizosphere. Higher-than-normal winter snowpacks cause the carbon isotope ratios of soil-respired CO2 to be depleted in 13C, reflecting a signal of lower photosynthetic water-use efficiency in the GPP that is transferred to the soil rhizosphere. Large-scale forest disturbance due to catastrophic tree mortality from mountain pine beetle attack causes an initial (2-3 year) reduction in Rs, which is attributable to the loss of GPP and its effect on Ra. This near-term reduction in Rs

  13. Fishing for ecosystem services

    USGS Publications Warehouse

    Pope, Kevin L.; Pegg, Mark A.; Cole, Nicholas W.; Siddons, Stephen F.; Fedele, Alexis D.; Harmon, Brian S.; Ruskamp, Ryan L.; Turner, Dylan R.; Uerling, Caleb C.

    2016-01-01

    Ecosystems are commonly exploited and manipulated to maximize certain human benefits. Such changes can degrade systems, leading to cascading negative effects that may be initially undetected, yet ultimately result in a reduction, or complete loss, of certain valuable ecosystem services. Ecosystem-based management is intended to maintain ecosystem quality and minimize the risk of irreversible change to natural assemblages of species and to ecosystem processes while obtaining and maintaining long-term socioeconomic benefits. We discuss policy decisions in fishery management related to commonly manipulated environments with a focus on influences to ecosystem services. By focusing on broader scales, managing for ecosystem services, and taking a more proactive approach, we expect sustainable, quality fisheries that are resilient to future disturbances. To that end, we contend that: (1) management always involves tradeoffs; (2) explicit management of fisheries for ecosystem services could facilitate a transition from reactive to proactive management; and (3) adaptive co-management is a process that could enhance management for ecosystem services. We propose adaptive co-management with an ecosystem service framework where actions are implemented within ecosystem boundaries, rather than political boundaries, through strong interjurisdictional relationships.

  14. On whether mirror neurons play a significant role in processing affective prosody.

    PubMed

    Ramachandra, Vijayachandra

    2009-02-01

    Several behavioral and neuroimaging studies have indicated that both right and left cortical structures and a few subcortical ones are involved in processing affective prosody. Recent investigations have shown that the mirror neuron system plays a crucial role in several higher-level functions such as empathy, theory of mind, language, etc., but no studies so far link the mirror neuron system with affective prosody. In this paper is a speculation that the mirror neuron system, which serves as a common neural substrate for different higher-level functions, may play a significant role in processing affective prosody via its connections with the limbic lobe. Actual research must apply electrophysiological and neuroimaging techniques to assess whether the mirror neuron systems underly affective prosody in humans.

  15. Ecotoxicology of tropical marine ecosystems

    SciTech Connect

    Peters, E.C.; Gassman, N.J.; Firman, J.C.; Richmond, R.H.; Power, E.A.

    1997-01-01

    The negative effects of chemical contaminants on tropical marine ecosystems are of increasing concern as human populations expand adjacent to these communities. Watershed streams and ground water carry a variety of chemicals from agricultural, industrial, and domestic activities, while winds and currents transport pollutants from atmospheric and oceanic sources to these coastal ecosystems. The implications of the limited information available on impacts of chemical stressors on mangrove forests, seagrass meadows, and coral reefs are discussed in the context of ecosystem management and ecological risk assessment. Three classes of pollutants have received attention: heavy metals, petroleum, and synthetic organics. Heavy metals have been detected in all three ecosystems, causing physiological stress, reduced reproductive success, and outright mortality in associated invertebrates and fishes. Oil spills have been responsible for the destruction of entire coastal shallow-water communities, with recovery requiring years. Herbicides are particularly detrimental to mangroves and seagrasses and adversely affect the animal-algal symbioses in corals. Pesticides interfere with chemical cues responsible for key biological processes, including reproduction and recruitment of a variety of organisms. Information is lacking with regard to long-term recovery, indicator species, and biomarkers for tropical communities. Critical areas that are beginning to be addressed include the development of appropriate benchmarks for risk assessment, baseline monitoring criteria, and effective management strategies to protect tropical marine ecosystems in the face of mounting anthropogenic disturbance.

  16. Extreme sensory processing patterns and their relation with clinical conditions among individuals with major affective disorders.

    PubMed

    Engel-Yeger, Batya; Muzio, Caterina; Rinosi, Giorgio; Solano, Paola; Geoffroy, Pierre Alexis; Pompili, Maurizio; Amore, Mario; Serafini, Gianluca

    2016-02-28

    Previous studies highlighted the involvement of sensory perception in emotional processes. However, the role of extreme sensory processing patterns expressed in hyper- or hyposensitivity was not thoroughly considered. The present study, in real life conditions, examined the unique sensory processing patterns of individuals with major affective disorders and their relationship with psychiatric symptomatology. The sample consisted of 105 participants with major affective conditions ranging in age from 20 to 84 years (mean=56.7±14.6). All participants completed the Temperament Evaluation of Memphis, Pisa, Paris and San Diego (TEMPS-A), the second version of the Beck Depression Inventory (BDI-II), and Adolescent/Adult Sensory Profile (AASP). Sensory sensitivity/avoiding hypersensitivity patterns and low registration (a hyposensitivity pattern) were prevalent among our sample as compared to normative data. About seventy percent of the sample showed lower seeking tendency. Stepwise regression analyses revealed that depression and anxious/cyclothymic affective temperaments were predicted by sensory sensory/avoiding. Anxious and irritable affective temperaments were predicted by low registration. Hyperthymic affective temperament and lower severity of depression were predicted by sensation seeking. Hyposensitivity or hypersensitivity may be "trait" markers of individuals with major affective disorders. Interventions should refer to the individual unique sensory profiles and their behavioral and functional impact in the context of real life.

  17. Affective priming effects of musical sounds on the processing of word meaning.

    PubMed

    Steinbeis, Nikolaus; Koelsch, Stefan

    2011-03-01

    Recent studies have shown that music is capable of conveying semantically meaningful concepts. Several questions have subsequently arisen particularly with regard to the precise mechanisms underlying the communication of musical meaning as well as the role of specific musical features. The present article reports three studies investigating the role of affect expressed by various musical features in priming subsequent word processing at the semantic level. By means of an affective priming paradigm, it was shown that both musically trained and untrained participants evaluated emotional words congruous to the affect expressed by a preceding chord faster than words incongruous to the preceding chord. This behavioral effect was accompanied by an N400, an ERP typically linked with semantic processing, which was specifically modulated by the (mis)match between the prime and the target. This finding was shown for the musical parameter of consonance/dissonance (Experiment 1) and then extended to mode (major/minor) (Experiment 2) and timbre (Experiment 3). Seeing that the N400 is taken to reflect the processing of meaning, the present findings suggest that the emotional expression of single musical features is understood by listeners as such and is probably processed on a level akin to other affective communications (i.e., prosody or vocalizations) because it interferes with subsequent semantic processing. There were no group differences, suggesting that musical expertise does not have an influence on the processing of emotional expression in music and its semantic connotations.

  18. No effect of inversion on attentional and affective processing of facial expressions.

    PubMed

    Lipp, Ottmar V; Price, Sarah M; Tellegen, Cassandra L

    2009-04-01

    The decrease in recognition performance after face inversion has been taken to suggest that faces are processed holistically. Three experiments, 1 with schematic and 2 with photographic faces, were conducted to assess whether face inversion also affected visual search for and implicit evaluation of facial expressions of emotion. The 3 visual search experiments yielded the same differences in detection speed between different facial expressions of emotion for upright and inverted faces. Threat superiority effects, faster detection of angry than of happy faces among neutral background faces, were evident in 2 experiments. Face inversion did not affect explicit or implicit evaluation of face stimuli as assessed with verbal ratings and affective priming. Happy faces were evaluated as more positive than angry, sad, or fearful/scheming ones regardless of orientation. Taken together these results seem to suggest that the processing of facial expressions of emotion is not impaired if holistic processing is disrupted.

  19. Intuitive (in)coherence judgments are guided by processing fluency, mood and affect.

    PubMed

    Sweklej, Joanna; Balas, Robert; Pochwatko, Grzegorz; Godlewska, Małgorzata

    2014-01-01

    Recently proposed accounts of intuitive judgments of semantic coherence assume that processing fluency results in a positive affective response leading to successful assessment of semantic coherence. The present paper investigates whether processing fluency may indicate semantic incoherence as well. In two studies, we employ a new paradigm in which participants have to detect an incoherent item among semantically coherent words. In Study 1, we show participants accurately indicating an incoherent item despite not being able to provide an accurate solution to coherent words. Further, this effect is modified by affective valence of solution words that are not retrieved from memory. Study 2 replicates those results and extend them by showing that mood moderates incoherence judgments independently of affective valence of solutions. The results support processing fluency account of intuitive semantic coherence judgments and show that it is not fluency per se but fluency variations that drive judgments.

  20. The Global Ecosystem Dynamics Investigation

    NASA Astrophysics Data System (ADS)

    Dubayah, R.; Goetz, S. J.; Blair, J. B.; Fatoyinbo, T. E.; Hansen, M.; Healey, S. P.; Hofton, M. A.; Hurtt, G. C.; Kellner, J.; Luthcke, S. B.; Swatantran, A.

    2014-12-01

    Spaceborne lidar has been identified as a key technology by the international ecosystem science community because it enables accurate estimates of canopy structure and biomass and forms the basis for fusion approaches that extend the capabilities of existing and planned radar missions, such as the NASA-ISRO SAR and the ESA BIOMASS mission. The Global Ecosystems Dynamics Investigation Lidar (GEDI Lidar) was recently selected by NASA's Earth Ventures Instrument (EVI) program. From its vantage point on the International Space Station, GEDI Lidar provides high-resolution observations of forest vertical structure and addresses three, core science questions: What is the aboveground carbon balance of the land surface? What role will the land surface play in mitigating atmospheric CO2 in the coming decades? How does ecosystem structure affect habitat quality and biodiversity? GEDI informs these science questions by making billions of lidar waveform observations of canopy structure over its nominal one year mission length. The instrument uses three laser transmitters to produce 14 parallel tracks of 25 m footprints. These canopy measurements are then used to measure biomass and in fusion with radar and other remote sensing data to quantify changes in biomass resulting from disturbance and recovery. GEDI further marries ecosystem structure from lidar with ecosystem modeling to predict the sequestration potential of existing forests and to evaluate the impact of policy-driven afforestation and reforestation actions on sequestering additional carbon. Lastly, GEDI's observations of ecosystem structure provide a mapping of critical habitat metrics at the fine scales required for understanding the patterns, processes, and controls on biodiversity and habitat quality. The selection of GEDI Lidar, when combined with the rapid advancement of new radar missions and the availability of long-term land cover archives from passive optical sensors, ushers in an exciting new era of land

  1. Principles of ecosystem sustainability

    SciTech Connect

    Chapin, F.S. III; Torn, M.S.; Tateno, Masaki

    1996-12-01

    Many natural ecosystems are self-sustaining, maintaining an characteristic mosaic of vegetation types of hundreds to thousands of years. In this article we present a new framework for defining the conditions that sustain natural ecosystems and apply these principles to sustainability of managed ecosystems. A sustainable ecosystem is one that, over the normal cycle of disturbance events, maintains its characteristics diversity of major functional groups, productivity, and rates of biogeochemical cycling. These traits are determined by a set of four {open_quotes}interactive controls{close_quotes} (climate, soil resource supply, major functional groups of organisms, and disturbance regime) that both govern and respond to ecosystem processes. Ecosystems cannot be sustained unless the interactive controls oscillate within stable bounds. This occurs when negative feedbacks constrain changes in these controls. For example, negative feedbacks associated with food availability and predation often constrain changes in the population size of a species. Linkages among ecosystems in a landscape can contribute to sustainability by creating or extending the feedback network beyond a single patch. The sustainability of managed systems can be increased by maintaining interactive controls so that they form negative feedbacks within ecosystems and by using laws and regulations to create negative feedbacks between ecosystems and human activities, such as between ocean ecosystems and marine fisheries. Degraded ecosystems can be restored through practices that enhance positive feedbacks to bring the ecosystem to a state where the interactive controls are commensurate with desired ecosystem characteristics. The possible combinations of interactive controls that govern ecosystem traits are limited by the environment, constraining the extent to which ecosystems can be managed sustainably for human purposes. 111 refs., 3 figs., 2 tabs.

  2. Affective processing of loved familiar faces: integrating central and peripheral electrophysiological measures.

    PubMed

    Guerra, Pedro; Vico, Cynthia; Campagnoli, Rafaela; Sánchez, Alicia; Anllo-Vento, Lourdes; Vila, Jaime

    2012-07-01

    A major problem in the electrophysiological studies of emotional processing linked to recognition of familiar faces is the unambiguous differentiation of effects due to emotional valence, arousal, and familiarity. The present paper summarizes a set of three studies aimed at investigating the affective processing of loved familiar faces using Lang's picture-viewing paradigm, with a special emphasis on teasing apart the individual contributions of affective valence, undifferentiated emotional arousal, and familiarity The results of the three studies support the conclusion that viewing the faces of familiar loved ones elicits an intense positive emotional reaction that cannot be explained either by familiarity or arousal alone. PMID:21689694

  3. Pan-Eurasian experiment (PEEX) establishing a process towards high level Pan-Eurasian atmosphere-ecosystem observation networks

    NASA Astrophysics Data System (ADS)

    Lappalainen, Hanna K.; Petäjä, Tuukka; Zaytzeva, Nina; Viisanen, Yrjö; Kotlyakov, Vladimir; Kasimov, Nikolay; Bondur, Valery; Matvienko, Gennady; Zilitinkevich, Sergej; Kulmala, Markku

    2014-05-01

    Pan-Eurasian Experiment (PEEX) is a new multidisciplinary research approach aiming at resolving the major uncertainties in the Earth system science and global sustainability questions in the Arctic and boreal Pan-Eurasian regions (Kulmala et al. 2011). The main goal of PEEX Research agenda is to contribute to solving the scientific questions that are specifically important for the Pan-Eurasian region in the coming years, in particular the global climate change and its consequences to nature and human society. Pan Eurasian region represents one the Earth most extensive areas of boreal forest (taiga) and the largest natural wetlands, thus being a significant source area of trace gas emissions, biogenic aerosol particles, and source and sink area for the greenhouse gas (GHG) exchange in a global scale (Guenther et al. 1995, Timkovsky et al. 2010, Tunved et al. 2006, Glagolev et al. 2010). One of the first activities of the PEEX initiative is to establish a process towards high level Pan-Eurasian Observation Networks. Siberian region is currently lacking a coordinated, coherent ground based atmosphere-ecosystem measurement network, which would be crucial component for observing and predicting the effects of climate change in the Northern Pan- Eurasian region The vision of the Pan-Eurasion network will be based on a hierarchical SMEAR-type (Stations Measuring Atmosphere-Ecosystem Interactions) integrated land-atmosphere observation system (Hari et al. 2009). A suite of stations have been selected for the Preliminary Phase of PEEX Observation network. These Preliminary Phase stations includes the SMEAR-type stations in Finland (SMEAR-I-II-II-IV stations), in Estonia (SMEAR-Järviselja) and in China (SMEAR-Nanjing) and selected stations in Russia and ecosystem station network in China. PEEX observation network will fill in the current observational gap in the Siberian region and bring the Siberian observation setup into international context with the with standardized or

  4. The natural history of Enewetak Atoll: Volume 1, The ecosystem: Environments, biotas, and processes

    SciTech Connect

    Devaney, D.M.; Reese, E.S.; Burch, B.L.; Helfrich, P.

    1987-01-01

    The two volumes of The Natural History of Enewetak Atoll summarize research done at the Mid-Pacific Research Laboratory from 1954 to 1984 under the auspices of the Department of Energy. The history of the laboratory and the reasons for its support by the United States Department of Energy are described in Chapter 1 of Volume 1. Volume 1 provides a synthesis of the research carried out under the subject headings of the respective chapters. Certain of the chapters, e.g., those on geology, subtidal and intertidal environments and ecology, and those on reef processes and trophic relationships, summarize a great diversity of research carried out by many scientists for many years. In contrast, the chapters on meteorology and oceanography summarize research carried out under one integrated program involving fewer scientists working over a shorter period. Individual chapters are processed separately for the data base.

  5. Low spatial frequency filtering modulates early brain processing of affective complex pictures.

    PubMed

    Alorda, Catalina; Serrano-Pedraza, Ignacio; Campos-Bueno, J Javier; Sierra-Vázquez, Vicente; Montoya, Pedro

    2007-11-01

    Recent research on affective processing has suggested that low spatial frequency information of fearful faces provide rapid emotional cues to the amygdala, whereas high spatial frequencies convey fine-grained information to the fusiform gyrus, regardless of emotional expression. In the present experiment, we examined the effects of low (LSF, <15 cycles/image width) and high spatial frequency filtering (HSF, >25 cycles/image width) on brain processing of complex pictures depicting pleasant, unpleasant, and neutral scenes. Event-related potentials (ERP), percentage of recognized stimuli and response times were recorded in 19 healthy volunteers. Behavioral results indicated faster reaction times in response to unpleasant LSF than to unpleasant HSF pictures. Unpleasant LSF pictures and pleasant unfiltered pictures also elicited significant enhancements of P1 amplitudes at occipital electrodes as compared to neutral LSF and unfiltered pictures, respectively; whereas no significant effects of affective modulation were found for HSF pictures. Moreover, mean ERP amplitudes in the time between 200 and 500ms post-stimulus were significantly greater for affective (pleasant and unpleasant) than for neutral unfiltered pictures; whereas no significant affective modulation was found for HSF or LSF pictures at those latencies. The fact that affective LSF pictures elicited an enhancement of brain responses at early, but not at later latencies, suggests the existence of a rapid and preattentive neural mechanism for the processing of motivationally relevant stimuli, which could be driven by LSF cues. Our findings confirm thus previous results showing differences on brain processing of affective LSF and HSF faces, and extend these results to more complex and social affective pictures.

  6. Early visual processing deficits in patients with schizophrenia during spatial frequency-dependent facial affect processing.

    PubMed

    Kim, Do-Won; Shim, Miseon; Song, Myeong Ju; Im, Chang-Hwan; Lee, Seung-Hwan

    2015-02-01

    Abnormal facial emotion recognition is considered as one of the key symptoms of schizophrenia. Only few studies have considered deficits in the spatial frequency (SF)-dependent visual pathway leading to abnormal facial emotion recognition in schizophrenia. Twenty-one patients with schizophrenia and 19 matched healthy controls (HC) were recruited for this study. Event-related potentials (ERP) were measured during presentation of SF-modulated face stimuli and their source imaging was analyzed. The patients showed reduced P100 amplitude for low-spatial frequency (LSF) pictures of fearful faces compared with the HC group. The P100 amplitude for high-spatial frequency (HSF) pictures of neutral faces was increased in the schizophrenia group, but not in the HC group. The neural source activities of the LSF fearful faces and HSF neutral faces led to hypo- and hyperactivation of the frontal lobe of subjects from the schizophrenia group and HC group, respectively. In addition, patients with schizophrenia showed enhanced N170 activation in the right hemisphere in the LSF condition, while the HC group did not. Our results suggest that deficits in the LSF-dependent visual pathway, which involves magnocellular neurons, impair early visual processing leading to dysfunctional facial emotion recognition in schizophrenia. Moreover, it suggests impaired bottom-up processing rather than top-down dysfunction for facial emotion recognition in these patients.

  7. Biogeochemical hotspots within forested landscapes: quantifying the functional role of vernal pools in ecosystem processes

    NASA Astrophysics Data System (ADS)

    Capps, K. A.; Rancatti, R.; Calhoun, A.; Hunter, M.

    2013-12-01

    Biogeochemical hotspots are characterized as small areas within a landscape matrix that show comparably high chemical reaction rates relative to surrounding areas. For small, natural features to generate biogeochemical hotspots within a landscape, their contribution to nutrient dynamics must be significant relative to nutrient demand of the surrounding landscape. In northeastern forests in the US, vernal pools are abundant, small features that typically fill in spring with snow melt and precipitation and dry by the end of the summer. Ephemeral flooding alters soil moisture and the depth of the oxic/anoxic boundary in the soil, which may affect leaf-litter decomposition rates and nutrient dynamics including denitrification. Additionally, pool-breeding organisms may influence nutrient dynamics via consumer-driven nutrient remineralization. We studied the effects of vernal pools on rates of leaf-litter decomposition and denitrification in forested habitats in Maine. Our results indicate leaf-litter decomposition and denitrification rates in submerged habitats of vernal pools were greater than in upland forest habitat. Our data also suggest pool-breeding organisms, such as wood frogs, may play an important role in nutrient dynamics within vernal pools. Together, the results suggest vernal pools may function as biogeochemical hotspots within forested landscapes.

  8. Tree species and functional traits but not species richness affect interrill erosion processes in young subtropical forests

    NASA Astrophysics Data System (ADS)

    Seitz, S.; Goebes, P.; Song, Z.; Bruelheide, H.; Härdtle, W.; Kühn, P.; Li, Y.; Scholten, T.

    2016-01-01

    Soil erosion is seriously threatening ecosystem functioning in many parts of the world. In this context, it is assumed that tree species richness and functional diversity of tree communities can play a critical role in improving ecosystem services such as erosion control. An experiment with 170 micro-scale run-off plots was conducted to investigate the influence of tree species and tree species richness as well as functional traits on interrill erosion in a young forest ecosystem. An interrill erosion rate of 47.5 Mg ha-1 a-1 was calculated. This study provided evidence that different tree species affect interrill erosion differently, while tree species richness did not affect interrill erosion in young forest stands. Thus, different tree morphologies have to be considered, when assessing soil erosion under forest. High crown cover and leaf area index reduced interrill erosion in initial forest ecosystems, whereas rising tree height increased it. Even if a leaf litter cover was not present, the remaining soil surface cover by stones and biological soil crusts was the most important driver for soil erosion control. Furthermore, soil organic matter had a decreasing influence on interrill erosion. Long-term monitoring of soil erosion under closing tree canopies is necessary, and a wide range of functional tree traits should be considered in future research.

  9. How does conversion of natural tropical rainforest ecosystems affect soil bacterial and fungal communities in the Nile river watershed of Uganda?

    PubMed

    Alele, Peter O; Sheil, Douglas; Surget-Groba, Yann; Lingling, Shi; Cannon, Charles H

    2014-01-01

    Uganda's forests are globally important for their conservation values but are under pressure from increasing human population and consumption. In this study, we examine how conversion of natural forest affects soil bacterial and fungal communities. Comparisons in paired natural forest and human-converted sites among four locations indicated that natural forest soils consistently had higher pH, organic carbon, nitrogen, and calcium, although variation among sites was large. Despite these differences, no effect on the diversity of dominant taxa for either bacterial or fungal communities was detected, using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). Composition of fungal communities did generally appear different in converted sites, but surprisingly, we did not observe a consistent pattern among sites. The spatial distribution of some taxa and community composition was associated with soil pH, organic carbon, phosphorus and sodium, suggesting that changes in soil communities were nuanced and require more robust metagenomic methods to understand the various components of the community. Given the close geographic proximity of the paired sampling sites, the similarity between natural and converted sites might be due to continued dispersal between treatments. Fungal communities showed greater environmental differentiation than bacterial communities, particularly according to soil pH. We detected biotic homogenization in converted ecosystems and substantial contribution of β-diversity to total diversity, indicating considerable geographic structure in soil biota in these forest communities. Overall, our results suggest that soil microbial communities are relatively resilient to forest conversion and despite a substantial and consistent change in the soil environment, the effects of conversion differed widely among sites. The substantial difference in soil chemistry, with generally lower nutrient quantity in converted sites, does bring

  10. How Does Conversion of Natural Tropical Rainforest Ecosystems Affect Soil Bacterial and Fungal Communities in the Nile River Watershed of Uganda?

    PubMed Central

    Alele, Peter O.; Sheil, Douglas; Surget-Groba, Yann; Lingling, Shi; Cannon, Charles H.

    2014-01-01

    Uganda's forests are globally important for their conservation values but are under pressure from increasing human population and consumption. In this study, we examine how conversion of natural forest affects soil bacterial and fungal communities. Comparisons in paired natural forest and human-converted sites among four locations indicated that natural forest soils consistently had higher pH, organic carbon, nitrogen, and calcium, although variation among sites was large. Despite these differences, no effect on the diversity of dominant taxa for either bacterial or fungal communities was detected, using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). Composition of fungal communities did generally appear different in converted sites, but surprisingly, we did not observe a consistent pattern among sites. The spatial distribution of some taxa and community composition was associated with soil pH, organic carbon, phosphorus and sodium, suggesting that changes in soil communities were nuanced and require more robust metagenomic methods to understand the various components of the community. Given the close geographic proximity of the paired sampling sites, the similarity between natural and converted sites might be due to continued dispersal between treatments. Fungal communities showed greater environmental differentiation than bacterial communities, particularly according to soil pH. We detected biotic homogenization in converted ecosystems and substantial contribution of β-diversity to total diversity, indicating considerable geographic structure in soil biota in these forest communities. Overall, our results suggest that soil microbial communities are relatively resilient to forest conversion and despite a substantial and consistent change in the soil environment, the effects of conversion differed widely among sites. The substantial difference in soil chemistry, with generally lower nutrient quantity in converted sites, does bring

  11. How does conversion of natural tropical rainforest ecosystems affect soil bacterial and fungal communities in the Nile river watershed of Uganda?

    PubMed

    Alele, Peter O; Sheil, Douglas; Surget-Groba, Yann; Lingling, Shi; Cannon, Charles H

    2014-01-01

    Uganda's forests are globally important for their conservation values but are under pressure from increasing human population and consumption. In this study, we examine how conversion of natural forest affects soil bacterial and fungal communities. Comparisons in paired natural forest and human-converted sites among four locations indicated that natural forest soils consistently had higher pH, organic carbon, nitrogen, and calcium, although variation among sites was large. Despite these differences, no effect on the diversity of dominant taxa for either bacterial or fungal communities was detected, using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). Composition of fungal communities did generally appear different in converted sites, but surprisingly, we did not observe a consistent pattern among sites. The spatial distribution of some taxa and community composition was associated with soil pH, organic carbon, phosphorus and sodium, suggesting that changes in soil communities were nuanced and require more robust metagenomic methods to understand the various components of the community. Given the close geographic proximity of the paired sampling sites, the similarity between natural and converted sites might be due to continued dispersal between treatments. Fungal communities showed greater environmental differentiation than bacterial communities, particularly according to soil pH. We detected biotic homogenization in converted ecosystems and substantial contribution of β-diversity to total diversity, indicating considerable geographic structure in soil biota in these forest communities. Overall, our results suggest that soil microbial communities are relatively resilient to forest conversion and despite a substantial and consistent change in the soil environment, the effects of conversion differed widely among sites. The substantial difference in soil chemistry, with generally lower nutrient quantity in converted sites, does bring

  12. 40 CFR 63.1037 - Alternative means of emission limitation: Enclosed-vented process units or affected facilities.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... negative pressure at all times while the process unit or affected facility is in operation to ensure that... limitation: Enclosed-vented process units or affected facilities. 63.1037 Section 63.1037 Protection of...-vented process units or affected facilities. (a) Use of closed vent system and control device....

  13. The sound of emotions-Towards a unifying neural network perspective of affective sound processing.

    PubMed

    Frühholz, Sascha; Trost, Wiebke; Kotz, Sonja A

    2016-09-01

    Affective sounds are an integral part of the natural and social environment that shape and influence behavior across a multitude of species. In human primates, these affective sounds span a repertoire of environmental and human sounds when we vocalize or produce music. In terms of neural processing, cortical and subcortical brain areas constitute a distributed network that supports our listening experience to these affective sounds. Taking an exhaustive cross-domain view, we accordingly suggest a common neural network that facilitates the decoding of the emotional meaning from a wide source of sounds rather than a traditional view that postulates distinct neural systems for specific affective sound types. This new integrative neural network view unifies the decoding of affective valence in sounds, and ascribes differential as well as complementary functional roles to specific nodes within a common neural network. It also highlights the importance of an extended brain network beyond the central limbic and auditory brain systems engaged in the processing of affective sounds.

  14. The sound of emotions-Towards a unifying neural network perspective of affective sound processing.

    PubMed

    Frühholz, Sascha; Trost, Wiebke; Kotz, Sonja A

    2016-09-01

    Affective sounds are an integral part of the natural and social environment that shape and influence behavior across a multitude of species. In human primates, these affective sounds span a repertoire of environmental and human sounds when we vocalize or produce music. In terms of neural processing, cortical and subcortical brain areas constitute a distributed network that supports our listening experience to these affective sounds. Taking an exhaustive cross-domain view, we accordingly suggest a common neural network that facilitates the decoding of the emotional meaning from a wide source of sounds rather than a traditional view that postulates distinct neural systems for specific affective sound types. This new integrative neural network view unifies the decoding of affective valence in sounds, and ascribes differential as well as complementary functional roles to specific nodes within a common neural network. It also highlights the importance of an extended brain network beyond the central limbic and auditory brain systems engaged in the processing of affective sounds. PMID:27189782

  15. "Responses of Soil Microorganisms and Microbial Mediated Processes During Succession to Elevated CO2 in Mediterranean-Type Ecosystems".

    SciTech Connect

    Dr. Michael Allen

    2000-11-27

    Summary Hypothesis 1. Mycorrhizal fungal types, diversity and activity will increase under elevated CO2. Generally activity increased and composition changed. No change in types was observed. It is important to note that overall nutrient cycling was affected by elevated CO2, largely by increasing turnover, not standing crop. These changes were not apparent at any one sampling date, but could only be determined over the longer course of the experiment. Hypothesis 2. Mycorrhizal fungal types, diversity and activity will decrease under NOx addition. Mycorrhizae showed no change in the % infection of mycorrhizae. However, the species composition changed and the relative form of N predominating changed, as increasing N turnover was apparent. Hypothesis 3. Mycorrhizal fungal types, diversity and activity will decline precipitously under elevated CO2 coupled with NOx additions. There are no CO2 X NOx field study facilities in our region. However, we undertook some small-scale plot fertilization studies. At the Michigan open-topped chambers, and in growth chamber studies we found that added N plus CO2 increased the allocation of C to the bacterial food web causing more rapid nutrient cycling and fewer mycorrhizae. Preliminary results indicate that the NO3 fertilization overwhelmed any CO2 effect and no significant interactions were found. We will re-evaluate how to undertake these studies. Hypothesis 4. Mycorrhizal fungal types, diversity and activity will decline under El Nino years and during La Nina years compared with more ?normal? years. Mycorrhizal activity was dramatically affected by precipitation. During wet, El Nino years, EM predominated with a shift to AM during dry, La Nina years. The total amount of fungal hyphae was higher during wetter years. These data suggest that understanding mycorrhizae by climate/CO2/ NOx interactions will be crucial in determining the patterns and rates of nutrient and carbon dynamics in ecosystems.

  16. The cocoa bean fermentation process: from ecosystem analysis to starter culture development.

    PubMed

    De Vuyst, L; Weckx, S

    2016-07-01

    Cocoa bean fermentation is still a spontaneous curing process to facilitate drying of nongerminating cocoa beans by pulp removal as well as to stimulate colour and flavour development of fermented dry cocoa beans. As it is carried out on farm, cocoa bean fermentation is subjected to various agricultural and operational practices and hence fermented dry cocoa beans of variable quality are obtained. Spontaneous cocoa bean fermentations carried out with care for approximate four days are characterized by a succession of particular microbial activities of three groups of micro-organisms, namely yeasts, lactic acid bacteria (LAB) and acetic acid bacteria (AAB), which results in well-fermented fully brown cocoa beans. This has been shown through a plethora of studies, often using a multiphasic experimental approach. Selected strains of several of the prevailing microbial species have been tested in appropriate cocoa pulp simulation media to unravel their functional roles and interactions as well as in small plastic vessels containing fresh cocoa pulp-bean mass to evaluate their capacity to dominate the cocoa bean fermentation process. Various starter cultures have been proposed for successful fermentation, encompassing both cocoa-derived and cocoa nonspecific strains of (hybrid) yeasts, LAB and AAB, some of which have been implemented on farms successfully.

  17. Product-to-parent reversion processes: Stream-hyporheic spiraling increases ecosystem exposure and environmental persistence

    NASA Astrophysics Data System (ADS)

    Ward, A. S.; Cwiertny, D. M.; Kolodziej, E. P.

    2014-12-01

    The product-to-parent reversion of metabolites of trenbolone acetate (TBA), a steroidal growth promoter used widely in beef cattle production, was recently observed to occur in environmental waters. The rapid forward reaction is by direct photolysis (i.e., photohydration), with the much slower reversion reaction occurring via dehydration in the dark. The objective of this study is to quantify the potential effect of this newly discovered reversible process on TBA metabolite concentrations and total bioactivity exposure in fluvial systems. Here, we demonstrate increased persistence of TBA metabolites in the stream and hyporheic zone due to the reversion process, increasing chronic and acute exposure to these endocrine-active compounds along a stream. The perpetually dark hyporheic zone is a key location for reversion in the system, ultimately providing a source of the parent compound to the stream and increasing mean in-stream concentration of 17α-trenbolone (17α-TBOH) by 40% of the input concentration under representative fluvial conditions. As such, regulatory frameworks for compounds undergoing product-to-parent reversion will require new approaches for assessing total exposure to bioactive compounds. Further, we demonstrate generalized cases for prediction of exposure for species with product-to-parent reversion in stream-hyporheic systems.

  18. The cocoa bean fermentation process: from ecosystem analysis to starter culture development.

    PubMed

    De Vuyst, L; Weckx, S

    2016-07-01

    Cocoa bean fermentation is still a spontaneous curing process to facilitate drying of nongerminating cocoa beans by pulp removal as well as to stimulate colour and flavour development of fermented dry cocoa beans. As it is carried out on farm, cocoa bean fermentation is subjected to various agricultural and operational practices and hence fermented dry cocoa beans of variable quality are obtained. Spontaneous cocoa bean fermentations carried out with care for approximate four days are characterized by a succession of particular microbial activities of three groups of micro-organisms, namely yeasts, lactic acid bacteria (LAB) and acetic acid bacteria (AAB), which results in well-fermented fully brown cocoa beans. This has been shown through a plethora of studies, often using a multiphasic experimental approach. Selected strains of several of the prevailing microbial species have been tested in appropriate cocoa pulp simulation media to unravel their functional roles and interactions as well as in small plastic vessels containing fresh cocoa pulp-bean mass to evaluate their capacity to dominate the cocoa bean fermentation process. Various starter cultures have been proposed for successful fermentation, encompassing both cocoa-derived and cocoa nonspecific strains of (hybrid) yeasts, LAB and AAB, some of which have been implemented on farms successfully. PMID:26743883

  19. Modelling carbon responses of tundra ecosystems to historical and projected climate: A comparison of a plot- and a global-scale ecosystem model to identify process-based uncertainties

    USGS Publications Warehouse

    Clein, J.S.; Kwiatkowski, B.L.; McGuire, A.D.; Hobbie, J.E.; Rastetter, E.B.; Melillo, J.M.; Kicklighter, D.W.

    2000-01-01

    We are developing a process-based modelling approach to investigate how carbon (C) storage of tundra across the entire Arctic will respond to projected climate change. To implement the approach, the processes that are least understood, and thus have the most uncertainty, need to be identified and studied. In this paper, we identified a key uncertainty by comparing the responses of C storage in tussock tundra at one site between the simulations of two models - one a global-scale ecosystem model (Terrestrial Ecosystem Model, TEM) and one a plot-scale ecosystem model (General Ecosystem Model, GEM). The simulations spanned the historical period (1921-94) and the projected period (1995-2100). In the historical period, the model simulations of net primary production (NPP) differed in their sensitivity to variability in climate. However, the long-term changes in C storage were similar in both simulations, because the dynamics of heterotrophic respiration (RH) were similar in both models. In contrast, the responses of C storage in the two model simulations diverged during the projected period. In the GEM simulation for this period, increases in RH tracked increases in NPP, whereas in the TEM simulation increases in RH lagged increases in NPP. We were able to make the long-term C dynamics of the two simulations agree by parameterizing TEM to the fast soil C pools of GEM. We concluded that the differences between the long-term C dynamics of the two simulations lay in modelling the role of the recalcitrant soil C. These differences, which reflect an incomplete understanding of soil processes, lead to quite different projections of the response of pan-Arctic C storage to global change. For example, the reference parameterization of TEM resulted in an estimate of cumulative C storage of 2032 g C m-2 for moist tundra north of 50??N, which was substantially higher than the 463 g C m-2 estimated for a parameterization of fast soil C dynamics. This uncertainty in the depiction of

  20. Combined unilateral lesions of the amygdala and orbital prefrontal cortex impair affective processing in rhesus monkeys.

    PubMed

    Izquierdo, Alicia; Murray, Elisabeth A

    2004-05-01

    The amygdala and orbital prefrontal cortex (PFo) interact as part of a system for affective processing. To assess whether there is a hemispheric functional specialization for the processing of emotion or reward or both in nonhuman primates, rhesus monkeys (Macaca mulatta) with combined lesions of the amygdala and PFo in one hemisphere, either left or right, were compared with unoperated controls on a battery of tasks that tax affective processing, including two tasks that tax reward processing and two that assess emotional reactions. Although the two operated groups did not differ from each other, monkeys with unilateral lesions, left and right, showed altered reward-processing abilities as evidenced by attenuated reinforcer devaluation effects and an impairment in object reversal learning relative to controls. In addition, both operated groups showed blunted emotional reactions to a rubber snake. By contrast, monkeys with unilateral lesions did not differ from controls in their responses to an unfamiliar human (human "intruder"). Although the results provide no support for a hemispheric specialization of function, they yield the novel finding that unilateral lesions of the amygdala-orbitofrontal cortical circuit in monkeys are sufficient to significantly disrupt affective processing. PMID:14711973

  1. Aeolian process effects on vegetation communities in an arid grassland ecosystem.

    PubMed

    Alvarez, Lorelei J; Epstein, Howard E; Li, Junran; Okin, Gregory S

    2012-04-01

    Many arid grassland communities are changing from grass dominance to shrub dominance, but the mechanisms involved in this conversion process are not completely understood. Aeolian processes likely contribute to this conversion from grassland to shrubland. The purpose of this research is to provide information regarding how vegetation changes occur in an arid grassland as a result of aeolian sediment transport. The experimental design included three treatment blocks, each with a 25 × 50 m area where all grasses, semi-shrubs, and perennial forbs were hand removed, a 25 × 50 m control area with no manipulation of vegetation cover, and two 10 × 25 m plots immediately downwind of the grass-removal and control areas in the prevailing wind direction, 19° north of east, for measuring vegetation cover. Aeolian sediment flux, soil nutrients, and soil seed bank were monitored on each treatment area and downwind plot. Grass and shrub cover were measured on each grass-removal, control, and downwind plot along continuous line transects as well as on 5 × 10 m subplots within each downwind area over four years following grass removal. On grass-removal areas, sediment flux increased significantly, soil nutrients and seed bank were depleted, and Prosopis glandulosa shrub cover increased compared to controls. Additionally, differential changes for grass and shrub cover were observed for plots downwind of vegetation-removal and control areas. Grass cover on plots downwind of vegetation-removal areas decreased over time (2004-2007) despite above average rainfall throughout the period of observation, while grass cover increased downwind of control areas; P. glandulosa cover increased on plots downwind of vegetation-removal areas, while decreasing on plots downwind of control areas. The relationships between vegetation changes and aeolian sediment flux were significant and were best described by a logarithmic function, with decreases in grass cover and increases in shrub cover

  2. [A field study of the effects of elevated CO2 concentration on physiology an ecosystem processes in Chesapeake Bay Wetland]. [Annual] progress report, 1989--1990

    SciTech Connect

    Not Available

    1990-12-31

    Research during 1988--1989 focused on several new aspects of the response of the salt marsh ecosystem to elevated CO{sub 2} of the effect of CO{sub 2} on biomass production into above and belowground tissues, nitrogen content, light response of photosynthesis of single leaves, leaf water potential and carbon dioxide and water vapor exchange between the plant canopy and the ambient air. Result from the work in 87 and 88 had shown that the C{sub 3} plant, Scirpus olneyi, responded vigorously to elevated CO{sub 2} but the two C{sub 4} species, Spartina patens and Distichlis spicata did not. The responses of photosynthesis were also reflected in the canopy and ecosystem processes: Carbon accumulated in the C{sub 3} community into belowground tissues but not in the C{sub 4} community suggesting that the main factor in the ecosystem responses would be photosynthesis and that the environmental controls on this process would determine the long-term ecosystem responses to rising CO{sub 2}. The main question at the outset of this project was: How much more carbon will be accumulated in the salt marsh ecosystem in a high CO{sub 2} atmosphere than is being accumulated under present CO{sub 2} concentration? This experiment has raised the possibility that rising CO{sub 2} will make the salt marsh ecosystem a bigger sink for carbon than we have previously thought it to be. By extrapolation, this finding suggests that other, terrestrial ecosystems may also become larger sinks for carbon.

  3. Facial Affect Processing and Depression Susceptibility: Cognitive Biases and Cognitive Neuroscience

    ERIC Educational Resources Information Center

    Bistricky, Steven L.; Ingram, Rick E.; Atchley, Ruth Ann

    2011-01-01

    Facial affect processing is essential to social development and functioning and is particularly relevant to models of depression. Although cognitive and interpersonal theories have long described different pathways to depression, cognitive-interpersonal and evolutionary social risk models of depression focus on the interrelation of interpersonal…

  4. Social Information Processing in Children: Specific Relations to Anxiety, Depression, and Affect

    ERIC Educational Resources Information Center

    Luebbe, Aaron M.; Bell, Debora J.; Allwood, Maureen A.; Swenson, Lance P.; Early, Martha C.

    2010-01-01

    Two studies examined shared and unique relations of social information processing (SIP) to youth's anxious and depressive symptoms. Whether SIP added unique variance over and above trait affect in predicting internalizing symptoms was also examined. In Study 1, 215 youth (ages 8-13) completed symptom measures of anxiety and depression and a…

  5. 43 CFR 2.4 - Does where you send your request affect its processing?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... OF INFORMATION ACT; RECORDS AND TESTIMONY How To Make a Request § 2.4 Does where you send your request affect its processing? (a) A request to a particular bureau component (for example, a request addressed to a regional or field office) will be presumed to seek only records from that...

  6. 43 CFR 2.6 - How will fee information affect the processing of your request?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... FREEDOM OF INFORMATION ACT; RECORDS AND TESTIMONY How To Make a Request § 2.6 How will fee information... 43 Public Lands: Interior 1 2013-10-01 2013-10-01 false How will fee information affect the... associated with processing the request, that you will pay fees up to a specified amount, and/or that you...

  7. 43 CFR 2.6 - How will fee information affect the processing of your request?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... FREEDOM OF INFORMATION ACT; RECORDS AND TESTIMONY How To Make a Request § 2.6 How will fee information... 43 Public Lands: Interior 1 2014-10-01 2014-10-01 false How will fee information affect the... associated with processing the request, that you will pay fees up to a specified amount, and/or that you...

  8. 43 CFR 2.4 - Does where you send your request affect its processing?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... OF INFORMATION ACT; RECORDS AND TESTIMONY How To Make a Request § 2.4 Does where you send your request affect its processing? (a) A request to a particular bureau component (for example, a request addressed to a regional or field office) will be presumed to seek only records from that...

  9. Factors Affecting Christian Parents' School Choice Decision Processes: A Grounded Theory Study

    ERIC Educational Resources Information Center

    Prichard, Tami G.; Swezey, James A.

    2016-01-01

    This study identifies factors affecting the decision processes for school choice by Christian parents. Grounded theory design incorporated interview transcripts, field notes, and a reflective journal to analyze themes. Comparative analysis, including open, axial, and selective coding, was used to reduce the coded statements to five code families:…

  10. Approaching the Affective Factors of Information Seeking: The Viewpoint of the Information Search Process Model

    ERIC Educational Resources Information Center

    Savolainen, Reijo

    2015-01-01

    Introduction: The article contributes to the conceptual studies of affective factors in information seeking by examining Kuhlthau's information search process model. Method: This random-digit dial telephone survey of 253 people (75% female) living in a rural, medically under-serviced area of Ontario, Canada, follows-up a previous interview study…

  11. Transactional Distance among Open University Students: How Does it Affect the Learning Process?

    ERIC Educational Resources Information Center

    Kassandrinou, Amanda; Angelaki, Christina; Mavroidis, Ilias

    2014-01-01

    This study examines the presence of transactional distance among students, the factors affecting it, as well as the way it influences the learning process of students in a blended distance learning setting in Greece. The present study involved 12 postgraduate students of the Hellenic Open University (HOU). A qualitative research was conducted,…

  12. Processes affecting the transport of nitrogen in groundwater and factors related to slope position

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nitrate (NO3-) pollution of water resources has been a major problem for years, causing contaminated water supplies, harmful effects on human health, and widespread eutrophication of fresh water resources. The main objectives of this study were to: 1) understand the processes affecting NO3- transpor...

  13. Atypical Sensory Processing in Adolescents with an Autism Spectrum Disorder and Their Non-Affected Siblings

    ERIC Educational Resources Information Center

    De la Marche, Wouter; Steyaert, Jean; Noens, Ilse

    2012-01-01

    Atypical sensory processing is common in autism spectrum disorders (ASD). Specific profiles have been proposed in different age groups, but no study has focused specifically on adolescents. Identifying traits of ASD that are shared by individuals with ASD and their non-affected family members can shed light on the genetic underpinnings of ASD.…

  14. Linkages Between Biotic and Abiotic Belowground Processes in a Mojave Desert Ecosystem: Responses to Experimental Nitrogen and Water Additions

    NASA Astrophysics Data System (ADS)

    Verburg, P. S.; Marion, G. M.; Young, A. C.; Glanzmann, I.; Stevenson, B.; Arnone, J. A.; Nowak, R. S.

    2007-05-01

    Fine roots play a critical role in nutrient acquisition and water uptake. Yet it is unclear how fine roots in arid environments respond to increased nitrogen deposition and rainfall, two important global change factors in arid lands in the southwestern United States. In addition it is unclear how changes in root activity may impact soil CO2 concentrations, an important parameter affecting carbonate dynamics. We measured fine root length density (RLD) and soil CO2 concentrations for two years in experimentally manipulated plots in a Mojave Desert ecosystem. The study was conducted at the Mojave Global Change Facility located at the Nevada Test Site 60 miles northwest of Las Vegas. The treatments included: 1) three 25 mm water additions during the summer, 2) one nitrogen addition in the fall equivalent to 40 kg per hectare per year, 3) a combined water and nitrogen addition and, 4) untreated controls. Root data were collected using minirhizotron imaging approximately every 90 days underneath shrubs and intershrub areas. Soil CO2 concentrations were collected at the same sampling times and locations at 10, 40 and 90 cm depth using gas wells. The RLD showed clear seasonal patterns with the fastest increase in RLD occurring between February and April. During the winter the increase in RLD was higher underneath shrubs than in intershrub areas but during the summer months increases in RLD were similar under shrubs and in intershrub areas. Water additions slightly increased root mortality during the summer but this increase in mortality was not large enough to cause consistent differences in RLD between control and irrigated plots. Nitrogen addition had no effect on root dynamics in any of the plots. In contrast to RLD, irrigation consistently increased soil CO2 concentrations at all depths during the summer even when roots were not actively growing anymore. We speculate that the increased mortality under irrigation causes increased heterotrophic respiration which may

  15. Carbon isotope fractionation reveals distinct process of CH4 emission from different compartments of paddy ecosystem

    PubMed Central

    Zhang, Guangbin; Yu, Haiyang; Fan, Xianfang; Ma, Jing; Xu, Hua

    2016-01-01

    Carbon isotopic fractionations in the processes of CH4 emission from paddy field remain poorly understood. The δ13C-values of CH4 in association with production, oxidation and transport of CH4 in different pools of a paddy field were determined, and the stable carbon isotope fractionations were calibrated to assess relative contribution of acetate to CH4 production (fac) and fraction of CH4 oxidized (fox) by different pathways. The apparent isotope fractionation for CO2 conversion to CH4 (αapp) was 1.041–1.056 in the soil and 1.046–1.080 on the roots, indicating that fac was 10–60% and 0–50%, respectively. Isotope fractionation associated with CH4 oxidation (αox) was 1.021 ± 0.007 in the soil and 1.013 ± 0.005 on the roots, and the transport fractionation (εtransport) by rice plants was estimated to be −16.7‰ ~ −11.1‰. Rhizospheric fox was about 30–100%, and it was more important at the beginning but decreased fast towards the end of season. Large value of fox was also observed at the soil-water interface and soil and roots surfaces, respectively. The results demonstrate that carbon isotopic fractionations which might be different in different conditions were sensitive to the estimations of fac and fox in paddy field. PMID:27251886

  16. Carbon isotope fractionation reveals distinct process of CH4 emission from different compartments of paddy ecosystem

    NASA Astrophysics Data System (ADS)

    Zhang, Guangbin; Yu, Haiyang; Fan, Xianfang; Ma, Jing; Xu, Hua

    2016-06-01

    Carbon isotopic fractionations in the processes of CH4 emission from paddy field remain poorly understood. The δ13C-values of CH4 in association with production, oxidation and transport of CH4 in different pools of a paddy field were determined, and the stable carbon isotope fractionations were calibrated to assess relative contribution of acetate to CH4 production (fac) and fraction of CH4 oxidized (fox) by different pathways. The apparent isotope fractionation for CO2 conversion to CH4 (αapp) was 1.041–1.056 in the soil and 1.046–1.080 on the roots, indicating that fac was 10–60% and 0–50%, respectively. Isotope fractionation associated with CH4 oxidation (αox) was 1.021 ± 0.007 in the soil and 1.013 ± 0.005 on the roots, and the transport fractionation (εtransport) by rice plants was estimated to be ‑16.7‰ ~ ‑11.1‰. Rhizospheric fox was about 30–100%, and it was more important at the beginning but decreased fast towards the end of season. Large value of fox was also observed at the soil-water interface and soil and roots surfaces, respectively. The results demonstrate that carbon isotopic fractionations which might be different in different conditions were sensitive to the estimations of fac and fox in paddy field.

  17. Rapid communication: Global-local processing affects recognition of distractor emotional faces.

    PubMed

    Srinivasan, Narayanan; Gupta, Rashmi

    2011-03-01

    Recent studies have shown links between happy faces and global, distributed attention as well as sad faces to local, focused attention. Emotions have been shown to affect global-local processing. Given that studies on emotion-cognition interactions have not explored the effect of perceptual processing at different spatial scales on processing stimuli with emotional content, the present study investigated the link between perceptual focus and emotional processing. The study investigated the effects of global-local processing on the recognition of distractor faces with emotional expressions. Participants performed a digit discrimination task with digits at either the global level or the local level presented against a distractor face (happy or sad) as background. The results showed that global processing associated with broad scope of attention facilitates recognition of happy faces, and local processing associated with narrow scope of attention facilitates recognition of sad faces. The novel results of the study provide conclusive evidence for emotion-cognition interactions by demonstrating the effect of perceptual processing on emotional faces. The results along with earlier complementary results on the effect of emotion on global-local processing support a reciprocal relationship between emotional processing and global-local processing. Distractor processing with emotional information also has implications for theories of selective attention.

  18. Columbia River Estuary Ecosystem Classification Ecosystem Complex

    USGS Publications Warehouse

    Cannon, Charles M.; Ramirez, Mary F.; Heatwole, Danelle W.; Burke, Jennifer L.; Simenstad, Charles A.; O'Connor, Jim E.; Marcoe, Keith Marcoe

    2012-01-01

    Estuarine ecosystems are controlled by a variety of processes that operate at multiple spatial and temporal scales. Understanding the hierarchical nature of these