The role of recurrent disturbances for ecosystem multifunctionality.

Science.gov (United States)

Villnäs, Anna; Norkko, Joanna; Hietanen, Susanna; Josefson, Alf B; Lukkari, Kaarina; Norkko, Alf

2013-10-01

Ecosystem functioning is threatened by an increasing number of anthropogenic stressors, creating a legacy of disturbance that undermines ecosystem resilience. However, few empirical studies have assessed to what extent an ecosystem can tolerate repeated disturbances and sustain its multiple functions. By inducing increasingly recurring hypoxic disturbances to a sedimentary ecosystem, we show that the majority of individual ecosystem functions experience gradual degradation patterns in response to repetitive pulse disturbances. The degradation in overall ecosystem functioning was, however, evident at an earlier stage than for single ecosystem functions and was induced after a short pulse of hypoxia (i.e., three days), which likely reduced ecosystem resistance to further hypoxic perturbations. The increasing number of repeated pulse disturbances gradually moved the system closer to a press response. In addition to the disturbance regime, the changes in benthic trait composition as well as habitat heterogeneity were important for explaining the variability in overall ecosystem functioning. Our results suggest that disturbance-induced responses across multiple ecosystem functions can serve as a warning signal for losses of the adaptive capacity of an ecosystem, and might at an early stage provide information to managers and policy makers when remediation efforts should be initiated.

The effect of turbidity on recognition and generalization of predators and non-predators in aquatic ecosystems.

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Chivers, Douglas P; Al-Batati, Fawaz; Brown, Grant E; Ferrari, Maud C O

2013-02-01

Recent anthropogenic activities have caused a considerable change in the turbidity of freshwater and marine ecosystems. Concomitant with such perturbations are changes in community composition. Understanding the mechanisms through which species interactions are influenced by anthropogenic change has come to the forefront of many ecological disciplines. Here, we examine how a change in the availability of visual information influences the behavior of prey fish exposed to potential predators and non-predators. When fathead minnows, Pimephales promelas, were conditioned to recognize predators and non-predators in clear water, they showed a highly sophisticated ability to distinguish predators from non-predators. However, when learning occurred under conditions of increased turbidity, the ability of the prey to learn and generalize recognition of predators and non-predators was severely impaired. Our work highlights that changes at the community level associated with anthropogenic perturbations may be mediated through altered trophic interactions, and highlights the need to closely examine behavioral interactions to understand how species interactions change.

The effect of turbidity on recognition and generalization of predators and non-predators in aquatic ecosystems

Science.gov (United States)

Chivers, Douglas P; Al-Batati, Fawaz; Brown, Grant E; Ferrari, Maud C O

2013-01-01

Recent anthropogenic activities have caused a considerable change in the turbidity of freshwater and marine ecosystems. Concomitant with such perturbations are changes in community composition. Understanding the mechanisms through which species interactions are influenced by anthropogenic change has come to the forefront of many ecological disciplines. Here, we examine how a change in the availability of visual information influences the behavior of prey fish exposed to potential predators and non-predators. When fathead minnows, Pimephales promelas, were conditioned to recognize predators and non-predators in clear water, they showed a highly sophisticated ability to distinguish predators from non-predators. However, when learning occurred under conditions of increased turbidity, the ability of the prey to learn and generalize recognition of predators and non-predators was severely impaired. Our work highlights that changes at the community level associated with anthropogenic perturbations may be mediated through altered trophic interactions, and highlights the need to closely examine behavioral interactions to understand how species interactions change. PMID:23467451

Anthropogenic and natural influence on disease prevalence at the humanlivestockwildlife interface in the Serengeti ecosystem, Tanzania

OpenAIRE

Fyumagwa, Robert Dominikus

2012-01-01

Anthropogenic activities in ecosystems interfere with natural processes and cause habitat fragmentation and loss. Habitat fragmentation and loss restrict wildlife movement between populations consequently reducing the gene flow and genetic diversity. Increased human encroachment on wildlife habitat compromises immunity and disturbs host-pathogen relationships resulting in disease outbreaks in naïve populations. Tick-borne and infectious diseases are considered a major threat to the health of ...

Biochemical parameters in the blood of grass snakes (Natrix natrix in ecosystems under varying degrees of anthropogenic influence

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V. Y. Gasso

2016-09-01

Full Text Available The grass snake Natrix natrix (Linnaeus, 1758 is a partly hygrophilous species, distributed throughoutUkraine. This snake may be considered as a test object for environmental biomonitoring. Modern biochemical methods make it possible to obtain new scientific data on the effects of anthropogenic pressure on reptiles. Blood is a sensitive and informative indicator of the condition of an organism as it responds quickly to most changes in exogenous and endogenous factors, and reflects negative influences on both individual and, indirectly, populations. Changes in biochemical parameters may be used as biomarkers of the state of health of reptiles in ecosystems under varying degrees of anthropogenic pressure. Due the increase in anthropogenic influence the development and introduction of new methods of perceptual research, collection of up-to-date information and development of a database of reptile biochemical parameters have become an urgent priority. We collected mature individuals of the grass snake in floodplain ecosystems on the right bank of the Dnieper River in Dnipropetrovsk city. Grass snakes from floodplain habitats on the left bank of theSamaraRiver (O.L. Belgard Prysamarskii International Biosphere Station, Novomoskovsk district, Dnipropetrovsk province were studied as the control specimens. Our study demonstrated statistically significant differences between snakes from the study sites in the amount of albumin, urea and urea nitrogen, and inorganic phosphorus, as well as in alanine aminotransferase (ALT and alkaline phosphatise (AP activity. The amount of albumin in the blood serum of specimens from the anthropogenically transformed areas was significantly lower (by 25% than in that of the snakes caught in the control habitats. Decrease of the albumin concentration usually indicates abnormal processes in the kidneys and liver. According to the changes observed in the concentration of albumin, a corresponding increase in the albumin to

Different types of interactions of links in artificial and natural ecosystems under anthropogenic pressure

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Somova, Lydia; Pisman, Tamara; Mikheeva, Galina; Pechurkin, Nickolay

The life of organisms in an ecosystem depends not only on abiotic factors, but also on the interaction of organisms in which they come with each other. The study of mechanisms of the bioregulation based on ecological - biochemical interactions of ecosystem links is necessary to know the ecosystem development, its stability, survival of ecosystem organisms. It is of high importance as for the creation of artificial ecosystems, and also for the study of natural ecosystems under anthropogenic pressure on them. To create well-functioning ecosystems is necessary to study and consider the basic types of relationships between organisms. The basic types of interactions between organisms have been studied with simple terrestrial and water ecosystems. 1. The interaction of microbiocenoses and plants were studied in experiments with agrocenoses. Microbiocenosis proposed for increase of productivity of plants and for obtaining ecologically pure production of plants has been created taking into account mutual relationships between species of microorganisms. 2. The experimental model of the atmosphere closed «autotroph - heterotroph» system in which heterotrophic link was the mixed population of yeasts (Candida utilis and Candida guilliermondii) was studied. The algae Chlorella vulgaris was used as an autotroph link. It was shown, that the competition result for heterotrophic link depended on strategy of populations of yeast in relation to a substrate and oxygen utilization. 3. As a result of experimental and theoretical modelling of a competition of algae Chlorella vulgaris and Scenedesmus quadricauda at continuous cultivation, the impossibility of their coexistence in the conditions of limitation on nitrogen was shown. 4. Pray-predator interactions between algae (Chlorella vulgaris, Scenedesmus quadricauda) and invertebrates (Paramecium caudatum, Brachionus plicatilis) were studied in experimental closed ecosystem. This work was partly supported by the Russian Foundation for

Broader perspective on ecosystem sustainability: consequences for decision making.

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Sidle, Roy C; Benson, William H; Carriger, John F; Kamai, Toshitaka

2013-06-04

Although the concept of ecosystem sustainability has a long-term focus, it is often viewed from a static system perspective. Because most ecosystems are dynamic, we explore sustainability assessments from three additional perspectives: resilient systems; systems where tipping points occur; and systems subject to episodic resetting. Whereas foundations of ecosystem resilience originated in ecology, recent discussions have focused on geophysical attributes, and it is recognized that dynamic system components may not return to their former state following perturbations. Tipping points emerge when chronic changes (typically anthropogenic, but sometimes natural) push ecosystems to thresholds that cause collapse of process and function and may become permanent. Ecosystem resetting occurs when episodic natural disasters breach thresholds with little or no warning, resulting in long-term changes to environmental attributes or ecosystem function. An example of sustainability assessment of ecosystem goods and services along the Gulf Coast (USA) demonstrates the need to include both the resilient and dynamic nature of biogeomorphic components. Mountain road development in northwest Yunnan, China, makes rivers and related habitat vulnerable to tipping points. Ecosystems reset by natural disasters are also presented, emphasizing the need to understand the magnitude frequency and interrelationships among major disturbances, as shown by (i) the 2011 Great East Japan Earthquake and resulting tsunami, including how unsustainable urban development exacerbates geodisaster propagation, and (ii) repeated major earthquakes and associated geomorphic and vegetation disturbances in Papua New Guinea. Although all of these ecosystem perturbations and shifts are individually recognized, they are not embraced in contemporary sustainable decision making.

Climate forcing by anthropogenic aerosols

Energy Technology Data Exchange (ETDEWEB)

Charlson, R J; Schwartz, S E; Hales, J M; Cess, R D; Coakley, Jr, J A; Hansen, J E; Hofmann, D J [University of Washington, Seattle, WA (USA). Inst. for Environmental Studies, Dept. of Atmospheric Sciences

1992-01-24

Although long considered to be of marginal importance to global climate change, tropospheric aerosol contributes substantially to radiative forcing, and anthropogenic sulfate aerosol in particular has imposed a major perturbation to this forcing. Both the direct scattering of short wavelength solar radiation and the modification of the shortwave reflective properties of clouds by sulfate aerosol particles increase planetary albedo, thereby exerting a cooling influence on the planet. Current climate forcing due to anthropogenic sulfate is estimated to be -1 to -2 watts per square metre, globally averaged. This perturbation is comparable in magnitude to current anthropogenic greenhouse gas forcing but opposite in sign. Thus, the aerosol forcing has likely offset global greenhouse warming to a substantial degree. However, differences in geographical and seasonal distributions of these forcings preclude any simple compensation. Aerosol effects must be taken into account in evaluating anthropogenic influences on past, current, and projected future climate and in formulating policy regarding controls on emission of greenhouse gases and sulfur dioxide. Resolution of such policy issues requires integrated research on the magnitude and geographical distribution of aerosol climate forcing and on the controlling chemical and physical processes. 73 refs., 4 figs., 2 tabs.

Climate forcing by anthropogenic aerosols.

Science.gov (United States)

Charlson, R J; Schwartz, S E; Hales, J M; Cess, R D; Coakley, J A; Hansen, J E; Hofmann, D J

1992-01-24

Although long considered to be of marginal importance to global climate change, tropospheric aerosol contributes substantially to radiative forcing, and anthropogenic sulfate aerosol in particular has imposed a major perturbation to this forcing. Both the direct scattering of shortwavelength solar radiation and the modification of the shortwave reflective properties of clouds by sulfate aerosol particles increase planetary albedo, thereby exerting a cooling influence on the planet. Current climate forcing due to anthropogenic sulfate is estimated to be -1 to -2 watts per square meter, globally averaged. This perturbation is comparable in magnitude to current anthropogenic greenhouse gas forcing but opposite in sign. Thus, the aerosol forcing has likely offset global greenhouse warming to a substantial degree. However, differences in geographical and seasonal distributions of these forcings preclude any simple compensation. Aerosol effects must be taken into account in evaluating anthropogenic influences on past, current, and projected future climate and in formulating policy regarding controls on emission of greenhouse gases and sulfur dioxide. Resolution of such policy issues requires integrated research on the magnitude and geographical distribution of aerosol climate forcing and on the controlling chemical and physical processes.

Combined effects of local habitat, anthropogenic stress, and dispersal on stream ecosystems: a mesocosm experiment.

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Turunen, Jarno; Louhi, Pauliina; Mykrä, Heikki; Aroviita, Jukka; Putkonen, Emmi; Huusko, Ari; Muotka, Timo

2018-06-06

The effects of anthropogenic stressors on community structure and ecosystem functioning can be strongly influenced by local habitat structure and dispersal from source communities. Catchment land uses increase the input of fine sediments into stream channels, clogging the interstitial spaces of benthic habitats. Aquatic macrophytes enhance habitat heterogeneity and mediate important ecosystem functions, being thus a key component of habitat structure in many streams. Therefore, the recovery of macrophytes following in-stream habitat modification may be prerequisite for successful stream restoration. Restoration success is also affected by dispersal of organisms from the source community, with potentially strongest responses in relatively isolated headwater sites that receive limited amount of dispersing individuals. We used a factorial design in a set of stream mesocosms to study the independent and combined effects of an anthropogenic stressor (sand sedimentation), local habitat (macrophytes, i.e. moss transplants) and enhanced dispersal (two levels: high vs. low) on organic matter retention, algal accrual rate, leaf decomposition and macroinvertebrate community structure. Overall, all responses were simple additive effects with no interactions between treatments. Sand reduced algal accumulation, total invertebrate density and density of a few individual taxa. Mosses reduced algal accrual rate and algae-grazing invertebrates, but enhanced organic matter retention and detritus- and filter-feeders. Mosses also reduced macroinvertebrate diversity by increasing the dominance by a few taxa. Mosses also reduced leaf-mass loss, possibly because the organic matter retained by mosses provided an additional food source for leaf-shredding invertebrates and thus reduced shredder aggregation into leaf packs. The effect of mosses on macroinvertebrate communities and ecosystem functioning was distinct irrespective of the level of dispersal, suggesting strong environmental

Comparative bacterial community analysis in relatively pristine and anthropogenically influenced mangrove ecosystems on the Red Sea.

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Ullah, Riaz; Yasir, Muhammad; Khan, Imran; Bibi, Fehmida; Sohrab, Sayed Sartaj; Al-Ansari, Ahmed; Al-Abbasi, Fahad; Al-Sofyani, Abdulmohsin A; Daur, Ihsanullah; Lee, Seon-Woo; Azhar, Esam I

2017-08-01

Mangrove habitats are ecologically important ecosystems that are under severe pressure worldwide because of environmental changes and human activities. In this study, 16S rRNA gene amplicon deep-sequencing was used to compare bacterial communities in Red Sea mangrove ecosystems at anthropogenically influenced coastal sites with those at a relatively pristine island site. In total, 32 phyla were identified from the mangrove rhizospheres, with Proteobacteria predominating at each of the studied sites; however, the relative abundance was significantly decreased at the coastal sites (Mastorah, MG-MS; Ar-Rayis, MG-AR) compared with the pristine island site near Dhahban (MG-DBI). The phyla Actinobacteria, Firmicutes, Acidobacteria, Chloroflexi, Spirochetes, and Planctomycetes were present at a relative abundance of >1% at the MG-MS and MG-AR sites, but their concentration was <1% at the MG-DBI site. A total of 1659 operational taxonomic units (OTUs) were identified at the species level, and approximately 945 OTUs were shared across the different sampling sites. Multivariate principal coordinate data analysis separated the MG-DBI site from the MG-AR and MG-MS cluster. Specific bacterial taxa were enriched at each location, and in particular, the genera Pseudoalteromonas and Cobetia were predominantly identified in the MG-DBI site compared with the anthropogenically influenced coastal sites.

Recent changes in anthropogenic reactive nitrogen compounds

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Andronache, Constantin

2014-05-01

Significant anthropogenic perturbations of the nitrogen cycle are the result of rapid population growth, with mounting need for food and energy production. The increase of reactive nitrogen compounds (such as NOx, HNO3, NH3, and N2O) has a significant impact on human health, environment, and climate. NOx emissions contribute to O3 chemistry, aerosol formation and acidic precipitation. Ammonia is a notable atmospheric pollutant that may deteriorate ecosystems and contribute to respiratory problems. It reacts with acidic gases to form aerosols or is deposited back to ecosystems. The application of fertilizers accounts for most of the N2O production, adding to greenhouse gas emissions. We analyze the change of some reactive nitrogen compounds based on observations, in eastern United States. Results show that the control of NOx and SO2 emissions over the last decades caused a significant decrease of acidic deposition. The nitrate deposition is highest in eastern US, while the ammonium ion concentration is highest in central US regions. Overall, the inorganic nitrogen wet deposition from nitrate and ammonium is enhanced in central, and eastern US. Research shows that sensitive ecosystems in northeastern regions exhibit a slow recovery from the accumulated effects of acidic deposition. Given the growing demand for nitrogen in agriculture and industry, we discuss possible pathways to reduce the impact of excess reactive nitrogen on the environment.

Impacts of Nitrogen and Phosphorus: From Genomes to Natural Ecosystems and Agriculture

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Maïté S. Guignard

2017-07-01

Full Text Available Nitrogen (N and/or phosphorus (P availability can limit growth of primary producers across most of the world's aquatic and terrestrial ecosystems. These constraints are commonly overcome in agriculture by applying fertilizers to improve yields. However, excessive anthropogenic N and P inputs impact natural environments and have far-reaching ecological and evolutionary consequences, from individual species up to entire ecosystems. The extent to which global N and P cycles have been perturbed over the past century can be seen as a global fertilization experiment with significant redistribution of nutrients across different ecosystems. Here we explore the effects of N and P availability on stoichiometry and genomic traits of organisms, which, in turn, can influence: (i plant and animal abundances; (ii trophic interactions and population dynamics; and (iii ecosystem dynamics and productivity of agricultural crops. We articulate research priorities for a deeper understanding of how bioavailable N and P move through the environment and exert their ultimate impacts on biodiversity and ecosystem services.

Timing anthropogenic stressors to mitigate their impact on marine ecosystem resilience.

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Wu, Paul Pao-Yen; Mengersen, Kerrie; McMahon, Kathryn; Kendrick, Gary A; Chartrand, Kathryn; York, Paul H; Rasheed, Michael A; Caley, M Julian

2017-11-02

Better mitigation of anthropogenic stressors on marine ecosystems is urgently needed to address increasing biodiversity losses worldwide. We explore opportunities for stressor mitigation using whole-of-systems modelling of ecological resilience, accounting for complex interactions between stressors, their timing and duration, background environmental conditions and biological processes. We then search for ecological windows, times when stressors minimally impact ecological resilience, defined here as risk, recovery and resistance. We show for 28 globally distributed seagrass meadows that stressor scheduling that exploits ecological windows for dredging campaigns can achieve up to a fourfold reduction in recovery time and 35% reduction in extinction risk. Although the timing and length of windows vary among sites to some degree, global trends indicate favourable windows in autumn and winter. Our results demonstrate that resilience is dynamic with respect to space, time and stressors, varying most strongly with: (i) the life history of the seagrass genus and (ii) the duration and timing of the impacting stress.

The disturbance-diversity relationship: integrating biodiversity conservation and resource management in anthropogenic landscapes

OpenAIRE

Sharma, Lila Nath

2016-01-01

Disturbance, natural or anthropogenic, is ubiquitous to forest and grassland ecosystems across the globe. Many of these ecosystems have evolved alongside centuries old anthropogenic disturbance regimes. Understanding how disturbance impacts biodiversity and ecosystem service delivery is a topic of paramount importance as high biodiversity is likely to provide a wide array of ecosystem goods and services to an ever-growing human population. There is a general consensus that dist...

Impact of anthropogenic climate change and human activities on environment and ecosystem services in arid regions.

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Mahmoud, Shereif H; Gan, Thian Y

2018-08-15

The implications of anthropogenic climate change, human activities and land use change (LUC) on the environment and ecosystem services in the coastal regions of Saudi Arabia were analyzed. Earth observations data was used to drive land use categories between 1970 and 2014. Next, a Markov-CA model was developed to characterize the dynamic of LUC between 2014 and 2100 and their impacts on regions' climate and environment. Non-parametric change point and trend detection algorithms were applied to temperature, precipitation and greenhouse gases data to investigate the presence of anthropogenic climate change. Lastly, climate models were used to project future climate change between 2014 and 2100. The analysis of LUC revealed that between 1970 and 2014, built up areas experienced the greatest growth during the study period, leading to a significant monotonic trend. Urban areas increased by 2349.61km 2 between 1970 and 2014, an average increase of >53.4km 2 /yr. The projected LUC between 2014 and 2100 indicate a continued increase in urban areas and irrigated cropland. Human alteration of land use from natural vegetation and forests to other uses after 1970, resulted in a loss, degradation, and fragmentation, all of which usually have devastating effects on the biodiversity of the region. Resulting in a statistically significant change point in temperature anomaly after 1968 with a warming trend of 0.24°C/decade and a downward trend in precipitation anomaly of 12.2mm/decade. Total greenhouse gas emissions including all anthropogenic sources showed a statistically significant positive trend of 78,090Kt/decade after 1991. This is reflected in the future projection of temperature anomaly between 1900 and 2100 with a future warming trend of 0.19°C/decade. In conclusion, human activities, industrial revelation, deforestation, land use transformation and increase in greenhouse gases had significant implications on the environment and ecosystem services of the study area

Quantifying Anthropogenic Dust Emissions

Science.gov (United States)

Webb, Nicholas P.; Pierre, Caroline

2018-02-01

Anthropogenic land use and land cover change, including local environmental disturbances, moderate rates of wind-driven soil erosion and dust emission. These human-dust cycle interactions impact ecosystems and agricultural production, air quality, human health, biogeochemical cycles, and climate. While the impacts of land use activities and land management on aeolian processes can be profound, the interactions are often complex and assessments of anthropogenic dust loads at all scales remain highly uncertain. Here, we critically review the drivers of anthropogenic dust emission and current evaluation approaches. We then identify and describe opportunities to: (1) develop new conceptual frameworks and interdisciplinary approaches that draw on ecological state-and-transition models to improve the accuracy and relevance of assessments of anthropogenic dust emissions; (2) improve model fidelity and capacity for change detection to quantify anthropogenic impacts on aeolian processes; and (3) enhance field research and monitoring networks to support dust model applications to evaluate the impacts of disturbance processes on local to global-scale wind erosion and dust emissions.

Anthropogenic Drivers of Ecosystem Change: an Overview

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Gerald C. Nelson

2006-12-01

Full Text Available This paper provides an overview of what the Millennium Ecosystem Assessment (MA calls "indirect and direct drivers" of change in ecosystem services at a global level. The MA definition of a driver is any natural or human-induced factor that directly or indirectly causes a change in an ecosystem. A direct driver unequivocally influences ecosystem processes. An indirect driver operates more diffusely by altering one or more direct drivers. Global driving forces are categorized as demographic, economic, sociopolitical, cultural and religious, scientific and technological, and physical and biological. Drivers in all categories other than physical and biological are considered indirect. Important direct drivers include changes in climate, plant nutrient use, land conversion, and diseases and invasive species. This paper does not discuss natural drivers such as climate variability, extreme weather events, or volcanic eruptions.

A Conceptual Model of Natural and Anthropogenic Drivers and Their Influence on the Prince William Sound, Alaska, Ecosystem.

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Harwell, Mark A; Gentile, John H; Cummins, Kenneth W; Highsmith, Raymond C; Hilborn, Ray; McRoy, C Peter; Parrish, Julia; Weingartner, Thomas

2010-07-01

Prince William Sound (PWS) is a semi-enclosed fjord estuary on the coast of Alaska adjoining the northern Gulf of Alaska (GOA). PWS is highly productive and diverse, with primary productivity strongly coupled to nutrient dynamics driven by variability in the climate and oceanography of the GOA and North Pacific Ocean. The pelagic and nearshore primary productivity supports a complex and diverse trophic structure, including large populations of forage and large fish that support many species of marine birds and mammals. High intra-annual, inter-annual, and interdecadal variability in climatic and oceanographic processes as drives high variability in the biological populations. A risk-based conceptual ecosystem model (CEM) is presented describing the natural processes, anthropogenic drivers, and resultant stressors that affect PWS, including stressors caused by the Great Alaska Earthquake of 1964 and the Exxon Valdez oil spill of 1989. A trophodynamic model incorporating PWS valued ecosystem components is integrated into the CEM. By representing the relative strengths of driver/stressors/effects, the CEM graphically demonstrates the fundamental dynamics of the PWS ecosystem, the natural forces that control the ecological condition of the Sound, and the relative contribution of natural processes and human activities to the health of the ecosystem. The CEM illustrates the dominance of natural processes in shaping the structure and functioning of the GOA and PWS ecosystems.

Fluvial gravel stabilization by net-spinning Hydropsychid caddisflies: exploring the magnitude and geographic scope of ecosystem engineering effect and evaluating resistance to anthropogenic stresses

Science.gov (United States)

Daniels, M.; Albertson, L.; Sklar, L. S.; Tumolo, B.; Mclaughlin, M. K.

2017-12-01

Several studies have demonstrated the substantial effects that organisms can have on earth surface processes. Known as ecosystem engineers, in streams these organisms maintain, modify, or create physical habitat structure by influencing fluvial processes such as gravel movement, fine sediment deposition and bank erosion. However, the ecology of ecosystem engineers and the magnitude of ecosystem engineering effects in a world increasingly influence by anthropogenically-driven changes is not well understood. Here we present a synthesis of research findings on the potential gravel stabilization effects of Hydropsychid caddisflies, a globally distributed group of net-spinning insects that live in the benthic substrate of most freshwater streams. Hydropsychid caddisflies act as ecosystem engineers because these silk structures can fundamentally alter sediment transport conditions, including sediment stability and flow currents. The silk nets spun by these insects attach gravel grains to one another, increasing the shear stress required to initiate grain entrainment. In a series of independent laboratory experiments, we investigate the gravel size fractions most affected by these silk attachments. We also investigate the role of anthropogenic environmental stresses on ecosystem engineering potential by assessing the impact of two common stressors, high fine sediment loads and stream drying, on silk structures. Finally, an extensive field survey of grain size and Hydropsychid caddisfly population densities informs a watershed-scale network model of Hydropsychid caddisfly gravel stabilizing potential. Our findings provide some of the first evidence that caddisfly silk may be a biological structure that is resilient to various forms of human-mediated stress and that the effects of animal ecosystem engineers are underappreciated as an agent of resistance and recovery for aquatic communities experiencing changes in sediment loads and hydrologic regimes.

Use of stable nitrogen isotope signatures of riparian macrophytes as an indicator of anthropogenic N inputs to river ecosystems.

Science.gov (United States)

Kohzu, Ayato; Miyajima, Toshihiro; Tayasu, Ichiro; Yoshimizu, Chikage; Hyodo, Fujio; Matsui, Kiyoshi; Nakano, Takanori; Wada, Eitaro; Fujita, Noboru; Nagata, Toshi

2008-11-01

Deterioration of aquatic ecosystems resulting from enhanced anthropogenic N loading has become an issue of increasing concern worldwide, and methods are needed to trace sources of N in rivers. Because nitrate from sewage is enriched in 15N relative to nitrate from natural soils, delta(15)N values of stream nitrate (delta(15)Nnitrate) should be an appropriate index of anthropogenic N loading to rivers, as should the delta(15)N values of riparian plants (delta(15)Nplant) because they are consumers of nitrate. We determined the delta(15)N values of stream nitrate and six species of riparian macrophytes in 31 rivers in the Lake Biwa Basin in Japan. We then tested the correlation between these values and various land-use parameters, including the percentage of land used for residential and agricultural purposes as well as for natural areas. These delta(15)N values were significantly positively correlated with land use (%) that had a high N load (i.e., residential or agricultural use) and significantly negatively correlated with forest (%). These findings indicate that delta(15)N values of stream nitrate and riparian plants might be good indicators of anthropogenic inputs of nitrogen.

Anthropogenic climate change has altered primary productivity in Lake Superior.

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O'Beirne, M D; Werne, J P; Hecky, R E; Johnson, T C; Katsev, S; Reavie, E D

2017-06-09

Anthropogenic climate change has the potential to alter many facets of Earth's freshwater resources, especially lacustrine ecosystems. The effects of anthropogenic changes in Lake Superior, which is Earth's largest freshwater lake by area, are not well documented (spatially or temporally) and predicted future states in response to climate change vary. Here we show that Lake Superior experienced a slow, steady increase in production throughout the Holocene using (paleo)productivity proxies in lacustrine sediments to reconstruct past changes in primary production. Furthermore, data from the last century indicate a rapid increase in primary production, which we attribute to increasing surface water temperatures and longer seasonal stratification related to longer ice-free periods in Lake Superior due to anthropogenic climate warming. These observations demonstrate that anthropogenic effects have become a prominent influence on one of Earth's largest, most pristine lacustrine ecosystems.

Use of fish parasite species richness indices in analyzing anthropogenically impacted coastal marine ecosystems

Science.gov (United States)

Dzikowski, R.; Paperna, I.; Diamant, A.

2003-10-01

The diversity of fish parasite life history strategies makes these species sensitive bioindicators of aquatic ecosystem health. While monoxenous (single-host) species may persist in highly perturbed, extreme environments, this is not necessarily true for heteroxenous (multiple-host) species. As many parasites possess complex life cycles and are transmitted through a chain of host species, their dependency on the latter to complete their life cycles renders them sensitive to perturbed environments. In the present study, parasite communities of grey mullet Liza aurata and Liza ramada (Mugilidae) were investigated at two Mediterranean coastal sites in northern Israel: the highly polluted Kishon Harbor (KH) and the relatively unspoiled reference site, Ma'agan Michael (MM). Both are estuarine sites in which grey mullet are one of the most common fish species. The results indicate that fish at the polluted site had significantly less trematode metacercariae than fish at the reference site. Heteroxenous gut helminths were completely absent at the polluted sampling site. Consequently, KH fish displayed lower mean parasite species richness. At the same time, KH fish mean monoxenous parasite richness was higher, although the prevalence of different monoxenous taxa was variable. Copepods had an increased prevalence while monogenean prevalence was significantly reduced at the polluted site. This variability may be attributed to the differential susceptibility of the parasites to the toxicity of different pollutants, their concentration, the exposure time and possible synergistic effects. In this study, we used the cumulative species curve model that extrapolates "true" species richness of a given habitat as a function of increasing sample size. We considered the heteroxenous and monoxenous species separately for each site, and comparison of curves yielded significant results. It is proposed to employ this approach, originally developed for estimating the "true" parasite

Challenges for present and future estimates of anthropogenic carbon in the Indian Ocean

Science.gov (United States)

Goyet, C.; Touratier, F.

One of the main challenges we face today is to determine the evolution of the penetration of anthropogenic CO2 into the Indian Ocean and its impacts on marine and human life. Anthropogenic CO2 reaches the ocean via air-sea interactions as well as riverine inputs. It is then stored in the ocean and follows the oceanic circulation. As the carbon dioxide from the atmosphere penetrates into the sea, it reacts with water and acidifies the ocean. Consequently, the whole marine ecosystem is perturbed, thus potentially affecting the food web, which has, in turn, a direct impact on seafood supply for humans. Naturally, this will mainly affect the growing number of people living in coastal areas. Although anthropogenic CO2 in the ocean is identical with natural CO2 and therefore cannot be detected alone, many approaches are available today to estimate it. Since most of the results of these methods are globally in agreement, here we chose one of these methods, the tracer using oxygen, total inorganic carbon, and total alkalinity (TrOCA) approach, to compute the 3-D distribution of the anthropogenic CO2 concentrations throughout the Indian Ocean. The results of this distribution clearly illustrate the contrast between the Arabian Sea and the Bay of Bengal. They further show the importance of the southern part of this ocean that carries some anthropogenic CO2 at great depths. In order to determine the future anthropogenic impacts on the Indian Ocean, it is urgent and necessary to understand the present state. As the seawater temperature increases, how and how fast will the ocean circulation change? What will the impacts on seawater properties be? Many people are living on the bordering coasts, how will they be affected?

Anthropogenic impacts on marine ecosystems in Antarctica.

Science.gov (United States)

Aronson, Richard B; Thatje, Sven; McClintock, James B; Hughes, Kevin A

2011-03-01

Antarctica is the most isolated continent on Earth, but it has not escaped the negative impacts of human activity. The unique marine ecosystems of Antarctica and their endemic faunas are affected on local and regional scales by overharvesting, pollution, and the introduction of alien species. Global climate change is also having deleterious impacts: rising sea temperatures and ocean acidification already threaten benthic and pelagic food webs. The Antarctic Treaty System can address local- to regional-scale impacts, but it does not have purview over the global problems that impinge on Antarctica, such as emissions of greenhouse gases. Failure to address human impacts simultaneously at all scales will lead to the degradation of Antarctic marine ecosystems and the homogenization of their composition, structure, and processes with marine ecosystems elsewhere. © 2011 New York Academy of Sciences.

Responses of Surface Ozone Air Quality to Anthropogenic Nitrogen Deposition

Science.gov (United States)

Zhang, L.; Zhao, Y.; Tai, A. P. K.; Chen, Y.; Pan, Y.

2017-12-01

Human activities have substantially increased atmospheric deposition of reactive nitrogen to the Earth's surface, inducing unintentional effects on ecosystems with complex environmental and climate consequences. One consequence remaining unexplored is how surface air quality might respond to the enhanced nitrogen deposition through surface-atmosphere exchange. We combine a chemical transport model (GEOS-Chem) and a global land model (Community Land Model) to address this issue with a focus on ozone pollution in the Northern Hemisphere. We consider three processes that are important for surface ozone and can be perturbed by addition of atmospheric deposited nitrogen: emissions of biogenic volatile organic compounds (VOCs), ozone dry deposition, and soil nitrogen oxide (NOx) emissions. We find that present-day anthropogenic nitrogen deposition (65 Tg N a-1 to the land), through enhancing plant growth (represented as increases in vegetation leaf area index (LAI) in the model), could increase surface ozone from increased biogenic VOC emissions, but could also decrease ozone due to higher ozone dry deposition velocities. Meanwhile, deposited anthropogenic nitrogen to soil enhances soil NOx emissions. The overall effect on summer mean surface ozone concentrations show general increases over the globe (up to 1.5-2.3 ppbv over the western US and South Asia), except for some regions with high anthropogenic NOx emissions (0.5-1.0 ppbv decreases over the eastern US, Western Europe, and North China). We compare the surface ozone changes with those driven by the past 20-year climate and historical land use changes. We find that the impacts from anthropogenic nitrogen deposition can be comparable to the climate and land use driven surface ozone changes at regional scales, and partly offset the surface ozone reductions due to land use changes reported in previous studies. Our study emphasizes the complexity of biosphere-atmosphere interactions, which can have important

An ecological perspective on U.S. industrial poultry production: the role of anthropogenic ecosystems on the emergence of drug-resistant bacteria from agricultural environments.

Science.gov (United States)

Davis, Meghan F; Price, Lance B; Liu, Cindy Meng-Hsin; Silbergeld, Ellen K

2011-06-01

The industrialization of food animal production, specifically the widespread use of antimicrobials, not only increased pressure on microbial populations, but also changed the ecosystems in which antimicrobials and bacteria interact. In this review, we argue that industrial food animal production (IFAP) is appropriately defined as an anthropogenic ecosystem. This paper uses an ecosystem perspective to frame an examination of these changes in the context of U.S. broiler chicken production. This perspective emphasizes multiple modes by which IFAP has altered microbiomes and also suggests a means of generating hypotheses for understanding and predicting the ecological impacts of IFAP in terms of the resistome and the flow of resistance within and between microbiomes. Copyright © 2011 Elsevier Ltd. All rights reserved.

Explaining plant-soil diversity in Alpine ecosystems: more than just time since ecosystem succession started

Science.gov (United States)

Lane, Stuart; Baetz, Nico; Borgeaud, Laure; Verrecchia, Eric; Vittoz, Pascal

2014-05-01

Ecosystem succession in Alpine environments has been a focus of research for many decades. Following from the classic ideas of Jenny (1941, 1961), following perturbation, an ecosystem (flora, fauna and soil) should evolve as a function of time at a rate conditioned by external variables (relief, climate, geology). More recently, biogeomorphologists have focused upon the notion of co-evolution of geomorphic processes with ecosystems over very short through to very long (evolutionary) time-scales. Alpine environments have been a particular focus of models of co-evolution, as a means of understanding the rate of plant colonization of previously glaciated terrain. However, work in this field has tended to adopt an over simplified view of the relationship between perturbation and succession, including: how the landform and ecosystem itself conditions the impact of a perturbation to create a complex spatial impact; and how perturbations are not simply ecosystem destroyers but can be a significant source of ecosystem resources. What this means is that at the within landform scale, there may well be a complex and dynamic topographic and sedimentological template that co-evolves with the development of soil, flora and fauna. In this paper, we present and test conceptual models for such co-evolution for an Alpine alluvial fan and an Alpine piedmont braided river. We combine detailed floristic inventory with soil inventory, survey of edaphic variables above and below ground (e.g. vertical and lateral sedimentological structure, using electrical resistance tomography) and the analysis of historical aerial imagery. The floristic inventory shows the existence of a suite of distinct plant communities within each landform. Time since last perturbation is not a useful explanatory variable of the spatial distribution of these communities because: (1) perturbation impacts are spatially variable, as conditioned by the extent distribution of topographic, edaphic and ecological

Increased sensitivity to climate change in disturbed ecosystems

DEFF Research Database (Denmark)

Kroël-Dulay, György; Ransijn, Johannes; Schmidt, Inger Kappel

2015-01-01

Human domination of the biosphere includes changes to disturbance regimes, which push many ecosystems towards early-successional states. Ecological theory predicts that early-successional ecosystems are more sensitive to perturbations than mature systems, but little evidence supports this relatio......Human domination of the biosphere includes changes to disturbance regimes, which push many ecosystems towards early-successional states. Ecological theory predicts that early-successional ecosystems are more sensitive to perturbations than mature systems, but little evidence supports...... this relationship for the perturbation of climate change. Here we show that vegetation (abundance, species richness and species composition) across seven European shrublands is quite resistant to moderate experimental warming and drought, and responsiveness is associated with the dynamic state of the ecosystem...

Anthropogenic impact on environmental filamentous fungi communities along the Mediterranean littoral.

Science.gov (United States)

Al-Yasiri, Mohammed Hashim; Normand, Anne-Cécile; Mauffrey, Jean-François; Ranque, Stéphane

2017-07-01

We hypothesised that anthropogenic influences impact the filamentous fungi community structure and that particular species or species patterns might serve as markers to characterise ecosystems. This study aimed to describe the filamentous fungi community structure in various biotopes along the Mediterranean shore that were exposed to various levels of anthropogenic influence. We sampled filamentous fungi from yellow-legged gull faecal samples at five study sites along the Mediterranean littoral in southern France. The sites were characterised by variable anthropogenic influence, ranging from building rooftops in two cities to a natural reserve. The sites also included two suburban ecoclines, one of which was exposed to sewer pollution. Filamentous fungal colonies were quantified and identified via MALDI-TOF mass spectrometry. Interestingly, we found that both fungal diversity and abundance were low in urban areas compared with suburban ecocline or environments little affected by anthropogenic influence. Furthermore, some fungal species were clearly associated with particular environments. In particular, Mucor circinelloides was associated with a natural environment with little anthropogenic impact and distant from human settlements. Whereas, Scedosporium apiospermum was associated with an ecocline polluted by sewage. Our findings indicate that particular fungal species or species combination might be used as surrogate markers of ecosystems exposed to anthropogenic pollution. © 2017 Blackwell Verlag GmbH.

Ecosystem services in ECOCLIM

DEFF Research Database (Denmark)

Sørensen, Lise Lotte; Boegh, Eva; Bendtsen, J

that actions initiated to reduce anthropogenic GHG emissions are sustainable and not destructive to existing ecosystem services. Therefore it is important to address i.e. land use change in relation to the regulating services of the ecosystems, such as carbon sequestration and climate regulation. At present...... a thorough understanding of the ecosystem processes controlling the uptake or emissions of GHG is fundamental. Here we present ECOCLIM in the context of ecosystem services and the experimental studies within ECOCLIM which will lead to an enhanced understanding of Danish ecosystems....

Sustainability Of Coastal Fringe Ecosystems Against Anthropogenic Chemical Stressors

Science.gov (United States)

Plant-dominated coastal ecosystems provide least 21 ecological services including shoreline protection, contaminant removal and nursery and breeding habitat for biota. The value of these ecological services is as great as $28000/h. These ecosystems which include intertidal wetl...

Mapping 1995 global anthropogenic emissions of mercury

NARCIS (Netherlands)

Pacyna, Jozef M.; Pacyna, Elisabeth G.; Steenhuisen, Frits; Wilson, Simon

2003-01-01

This paper presents maps of anthropogenic Hg emissions worldwide within a 1degrees x 1degrees latitude/longitude grid system in 1995. As such, the paper is designed for modelers simulating the Hg transport within air masses and Hg deposition to aquatic and terrestrial ecosystems. Maps of total Hg

Anthropogenic pollutants affect ecosystem services of freshwater sediments. The need for a 'triad plus x' approach

Energy Technology Data Exchange (ETDEWEB)

Gerbersdorf, Sabine Ulrike; Wieprecht, Silke [Stuttgart Univ. (Germany). Dept. of Hydraulic Engineering and Water Resources Management; Hollert, Henner; Brinkmann, Markus [RWTH Aachen Univ. (Germany). Dept. of Ecosystem Analysis; Schuettrumpf, Holger [RWTH Aachen Univ. (Germany). Inst. of Hydraulic Engineering and Water Resources Management; Manz, Werner [Koblenz-Landau Univ., Koblenz (Germany). Inst. for Integrated Natural Sciences

2011-09-15

Purpose: Freshwater sediments and their attached microbial communities (biofilms) are essential features of rivers and lakes, providing valuable ecosystem services such as nutrient recycling or self-purification which extend beyond the aquatic environment. Anthropogenic pollutants, whether from the industrial era or as a result of our contemporary lifestyles, can negatively affect these functions with hitherto unknown consequences on ecology, the economy and human health. Thus far, the singular view of the involved disciplines such as ecotoxicology, environmental microbiology, hydrology and geomorphology has prevented a deeper understanding of this emerging issue. Main features: This paper discusses briefly the progressions and the state-of-the-art methods within the disciplines of concern related to contaminated sediments, ranging from ecotoxicological test systems, microbiological/molecular approaches to unravel changes of microbial ecosystems, up to the modelling of sediment transport and sorption/desorption of associated pollutants. The first bilateral research efforts on contaminated sediments include efforts to assess ecotoxicological sediment risk including sediment mobility (i.e. ecotoxicology and engineering), enhance bioremediation potential (i.e. microbiology and ecotoxicology) or to understand biostabilisation processes of sediments by microbial assemblages (i.e. microbiology and engineering). Conclusions and perspectives: In freshwater habitats, acute, chronic and mechanism-specific toxic effects on organisms, shifts in composition, structure and functionality of benthic microbial communities, as well as the obstruction of important ecosystem services by continuously discharged and long-deposited pollutants, should be related to the in situ sediment dynamics. To achieve an improved understanding of the ecology of freshwater sediments and the impairment of their important ecosystem functions by human-derived pollutants, we suggest a 'triad plus x

Anthropogenic Habitats Facilitate Dispersal of an Early Successional Obligate: Implications for Restoration of an Endangered Ecosystem.

Directory of Open Access Journals (Sweden)

Katrina E Amaral

Full Text Available Landscape modification and habitat fragmentation disrupt the connectivity of natural landscapes, with major consequences for biodiversity. Species that require patchily distributed habitats, such as those that specialize on early successional ecosystems, must disperse through a landscape matrix with unsuitable habitat types. We evaluated landscape effects on dispersal of an early successional obligate, the New England cottontail (Sylvilagus transitionalis. Using a landscape genetics approach, we identified barriers and facilitators of gene flow and connectivity corridors for a population of cottontails in the northeastern United States. We modeled dispersal in relation to landscape structure and composition and tested hypotheses about the influence of habitat fragmentation on gene flow. Anthropogenic and natural shrubland habitats facilitated gene flow, while the remainder of the matrix, particularly development and forest, impeded gene flow. The relative influence of matrix habitats differed between study areas in relation to a fragmentation gradient. Barrier features had higher explanatory power in the more fragmented site, while facilitating features were important in the less fragmented site. Landscape models that included a simultaneous barrier and facilitating effect of roads had higher explanatory power than models that considered either effect separately, supporting the hypothesis that roads act as both barriers and facilitators at all spatial scales. The inclusion of LiDAR-identified shrubland habitat improved the fit of our facilitator models. Corridor analyses using circuit and least cost path approaches revealed the importance of anthropogenic, linear features for restoring connectivity between the study areas. In fragmented landscapes, human-modified habitats may enhance functional connectivity by providing suitable dispersal conduits for early successional specialists.

The role of recurrent disturbances for ecosystem multifunctionality

OpenAIRE

Villnäs, Anna; Norkko, Joanna; Hietanen, Susanna; Josefson, Alf; Lukkari, Kaarina; Norkko, Alf

2013-01-01

Ecosystem functioning is threatened by an increasing number of anthropogenic stressors, creating a legacy of disturbance that undermines ecosystem resilience. However, few empirical studies have assessed to what extent an ecosystem can tolerate repeated disturbances and sustain its multiple functions. By inducing increasingly recurring hypoxic disturbances to a sedimentary ecosystem, we show that the majority of individual ecosystem functions experience gradual degradation patterns in respons...

Simulations of the global carbon cycle and anthropogenic CO2 transient

International Nuclear Information System (INIS)

Sarmiento, J.L.

1994-01-01

This research focuses on improving the understanding of the anthropogenic carbon dioxide transient using observations and models of the past and present. In addition, an attempt is made to develop an ability to predict the future of the carbon cycle in response to continued anthropogenic perturbations and climate change. Three aspects of the anthropogenic carbon budget were investigated: (1) the globally integrated budget at the present time; (2) the time history of the carbon budget; and (3) the spatial distribution of carbon fluxes. One of the major activities of this study was the participation in the model comparison study of Enting, et al. [1994] carried out in preparation for the IPCC 1994 report

Landscape-scale distribution and density of raptor populations wintering in anthropogenic-dominated desert landscapes

Science.gov (United States)

Adam E. Duerr; Tricia A. Miller; Kerri L. Cornell Duerr; Michael J. Lanzone; Amy Fesnock; Todd E. Katzner

2015-01-01

Anthropogenic development has great potential to affect fragile desert environments. Large-scale development of renewable energy infrastructure is planned for many desert ecosystems. Development plans should account for anthropogenic effects to distributions and abundance of rare or sensitive wildlife; however, baseline data on abundance and distribution of such...

Understanding the individual to implement the ecosystem approach to fisheries management.

Science.gov (United States)

Ward, Taylor D; Algera, Dirk A; Gallagher, Austin J; Hawkins, Emily; Horodysky, Andrij; Jørgensen, Christian; Killen, Shaun S; McKenzie, David J; Metcalfe, Julian D; Peck, Myron A; Vu, Maria; Cooke, Steven J

2016-01-01

Ecosystem-based approaches to fisheries management (EAFMs) have emerged as requisite for sustainable use of fisheries resources. At the same time, however, there is a growing recognition of the degree of variation among individuals within a population, as well as the ecological consequences of this variation. Managing resources at an ecosystem level calls on practitioners to consider evolutionary processes, and ample evidence from the realm of fisheries science indicates that anthropogenic disturbance can drive changes in predominant character traits (e.g. size at maturity). Eco-evolutionary theory suggests that human-induced trait change and the modification of selective regimens might contribute to ecosystem dynamics at a similar magnitude to species extirpation, extinction and ecological dysfunction. Given the dynamic interaction between fisheries and target species via harvest and subsequent ecosystem consequences, we argue that individual diversity in genetic, physiological and behavioural traits are important considerations under EAFMs. Here, we examine the role of individual variation in a number of contexts relevant to fisheries management, including the potential ecological effects of rapid trait change. Using select examples, we highlight the extent of phenotypic diversity of individuals, as well as the ecological constraints on such diversity. We conclude that individual phenotypic diversity is a complex phenomenon that needs to be considered in EAFMs, with the ultimate realization that maintaining or increasing individual trait diversity may afford not only species, but also entire ecosystems, with enhanced resilience to environmental perturbations. Put simply, individuals are the foundation from which population- and ecosystem-level traits emerge and are therefore of central importance for the ecosystem-based approaches to fisheries management.

The Chukchi Sea zoobenthos: contemporary conditions and trends in anthropogenic influence.

Directory of Open Access Journals (Sweden)

Kirievskaya Dubrava

2017-06-01

Full Text Available The Chukchi Sea is a key region where rapid changes of the Arctic environment have been observed recently. Benthos of the Chukchi Sea is a sensitive indicator of these changes. In addition, the benthos can be used as an indicator of the anthropogenic load on the marine environment. A lot of researches have been conducted in the different parts of the Chukchi Sea. In this paper we summarized all the data collected for the last 30 years to evaluate contemporary conditions of the Chukchi Sea benthos as well as to discuss a potential response of the benthic ecosystem to the anthropogenic load. The Chukchi Sea zoobenthos is characterized by relatively high biodiversity compared to the seas of the western Arctic Ocean. The spatial distribution of zoobenthos is non-uniform. It is caused by a lot of factors: depth, bottom and sediment temperature, geochemical structure of the sediments, hydrodynamics, etc. Present environmental conditions of the Chukchi Sea biota can be considered to be close to the average long-term norms. By the reason of climate change scientists started to observe northing displacement of subarctic and temperate species of the benthic ecosystem. The Chukchi Sea is still included into the area with low anthropogenic pressure. The main potential threat for the Chukchi sea benthos results from continued oil and gas exploration and sea transport. For example, benthos around oil-wells (the Burger and the Klondike contains pollutants at a high concentration. The risk of rising anthropogenic load on the Chukchi Sea ecosystem poses the problem to additionally identify vulnerable areas of increased ecological significance for later receiving conservation status.

Small Boreal Lake Ecosystem Evolution under the Influence of Natural and Anthropogenic Factors: Results of Multidisciplinary Long-Term Study

Directory of Open Access Journals (Sweden)

Liudmila Shirokova

2016-07-01

Full Text Available Small aquatic ecosystems of the boreal zone are known to be most sensitive indicators of on-going environmental change as well as local anthropogenic pressure, while being highly vulnerable to external impacts. Compared to rather detailed knowledge of the evolution of large and small lakes in Scandinavia and Canada, and large lakes in Eurasia, highly abundant small boreal lakes of northwest Russia have received very little attention, although they may become important centers of attraction of growing rural population in the near future. Here we present the results of a multidisciplinary, multi-annual study of a small boreal humic lake of NW Russia. A shallow (3 m and a deep (16 m site of this lake were regularly sampled for a range of chemical and biological parameters. Average multi-daily, summer-time values of the epilimnion (upper oxygenated layer of the lake provided indications of possible trends in temperature, nutrients, and bacterio-plankton concentration that revealed the local pollution impact in the shallow zone and overall environmental trend in the deep sampling point of the lake. Organic phosphorus, nitrate, and lead were found to be most efficient tracers of local anthropogenic pollution, especially visible in the surface layer of the shallow site of the lake. Cycling of trace elements between the epilimnion and hypolimnion is tightly linked to dissolved organic matter speciation and size fractionation due to the dominance of organic and organo-ferric colloids. The capacity of lake self-purification depends on the ratio of primary productivity to mineralization of organic matter. This ratio remained >1 both during winter and summer periods, which suggests a high potential of lake recovery from the input of allochthonous dissolved organic matter and local anthropogenic pollution.

Fluvial response to climate variations and anthropogenic perturbations for the Ebro River, Spain in the last 4,000 years.

Science.gov (United States)

Xing, Fei; Kettner, Albert J; Ashton, Andrew; Giosan, Liviu; Ibáñez, Carles; Kaplan, Jed O

2014-03-01

Fluvial sediment discharge can vary in response to climate changes and human activities, which in return influences human settlements and ecosystems through coastline progradation and retreat. To understand the mechanisms controlling the variations of fluvial water and sediment discharge for the Ebro drainage basin, Spain, we apply a hydrological model HydroTrend. Comparison of model results with a 47-year observational record (AD 1953-1999) suggests that the model adequately captures annual average water discharge (simulated 408 m(3)s(-1) versus observed 425 m(3)s(-1)) and sediment load (simulated 0.3 Mt yr(-1) versus observed 0.28 ± 0.04 Mt yr(-1)) for the Ebro basin. A long-term (4000-year) simulation, driven by paleoclimate and anthropogenic land cover change scenarios, indicates that water discharge is controlled by the changes in precipitation, which has a high annual variability but no long-term trend. Modeled suspended sediment load, however, has an increasing trend over time, which is closely related to anthropogenic land cover variations with no significant correlation to climatic changes. The simulation suggests that 4,000 years ago the annual sediment load to the ocean was 30.5 Mt yr(-1), which increased over time to 47.2 Mt yr(-1) (AD 1860-1960). In the second half of the 20th century, the emplacement of large dams resulted in a dramatic decrease in suspended sediment discharge, eventually reducing the flux to the ocean by more than 99% (mean value changes from 38.1 Mt yr(-1) to 0.3 Mt yr(-1)). Copyright © 2013 Elsevier B.V. All rights reserved.

Preservation of natural aquatic ecosystems by application of bottom coal ash based bioreactor for in situ treatment of anthropogenic effluents

Science.gov (United States)

Anker, Y.; Nisnevitch, M.; Tal, M.; Cahan, R.; Michael, E.

2012-12-01

One consequence of global climate change is recharge decrease at sub tropical and Mediterranean regions to both the surface and the ground fresh water resources. As a general rule, when water source quantity is reduced, the level of salination, as well as chemical and biological pollutants, tends to increase. The situation is more severe whenever the drainage basin is (a) heavily populated from urban, industrial and agricultural areas, (b) has wide areas of thin or non soil cover and (c) has a karstic structure and morphology. These latter conditions are typical to many regions around the Middle East; whereas pollution hazard to Mid Eastern streams is greater than to those in more humid regions owing to their relative small size and poor dilution capacity. The consequence of this ongoing and increasing anthropogenic pollution is endangerment of natural aquatic habitats and due to decrease in fresh water supply availability also to human sustainability. The ecological impact may involve transition of ephemeral (Wadi) streams into intermittent ones with the accompanied biodiversity change or extinction once the pollution is extreme. The impact on indigenous human communities might be as severe owing to drinking water quality decrease and the consequent decrease id quantity as well as damage to dryland farming. In setting of operations applied to the Yarkon Taninim watershed (central Israel) management, a pilot biofilter facility for sustainable preservation and rehabilitation of natural fluvial ecosystems was tested. This biofilter is planned to operate through low impact concept assimilating natural treatment processes occurring during runoff recharge through a porous flow media. The facility is constructed out of several grain sizes of bottom coal ash aggregate, which was found to be a better microbial mats growing stratum, compared to common natural aggregates such as tuff and lime pebbles (and also has an EPA directive for wastewater treatment). The biofilter is

Dating the period when intensive anthropogenic activity began to influence the Sanjiang Plain, Northeast China

Science.gov (United States)

Cong, Jinxin; Gao, Chuanyu; Zhang, Yan; Zhang, Shaoqing; He, Jiabao; Wang, Guoping

2016-01-01

Dating the start of intensive anthropogenic influence on ecosystems is important for identifying the conditions necessary for ecosystem recovery. However, few studies have focused on determining when anthropogenic influences on wetland began through sedimentary archives. To fill this critical gap in our knowledge, combustion sources and emission intensities, reconstructed via black carbon (BC) and polycyclic aromatic hydrocarbons (PAHs) were analyzed in two wetlands in the Sanjiang Plain in Northeast China. 14C provided age control for the sedimentary records. By combining previous sedimentary and archaeological studies, we attempt to date the beginning of intensive anthropogenic influences on the Sanjiang Plain. Our results showed that BC deposition fluxes increased from 0.02 to 0.7 g C/m2.yr during the last 10,000 years. An upward trend was apparent during the last 500 years. Before 1200 cal yr BP, human activities were minor, such that the wetland ecosystem in the Sanjiang Plain before this period may represent the reference conditions that for the recovery of these wetlands. As the human population increased after 1200 cal yr BP, combustion sources changed and residential areas became a major source of BC and PAHs. In this way, the wetland ecosystem gradually became more heavily influenced by human activities. PMID:26907560

Dating the period when intensive anthropogenic activity began to influence the Sanjiang Plain, Northeast China

Science.gov (United States)

Cong, Jinxin; Gao, Chuanyu; Zhang, Yan; Zhang, Shaoqing; He, Jiabao; Wang, Guoping

2016-02-01

Dating the start of intensive anthropogenic influence on ecosystems is important for identifying the conditions necessary for ecosystem recovery. However, few studies have focused on determining when anthropogenic influences on wetland began through sedimentary archives. To fill this critical gap in our knowledge, combustion sources and emission intensities, reconstructed via black carbon (BC) and polycyclic aromatic hydrocarbons (PAHs) were analyzed in two wetlands in the Sanjiang Plain in Northeast China. 14C provided age control for the sedimentary records. By combining previous sedimentary and archaeological studies, we attempt to date the beginning of intensive anthropogenic influences on the Sanjiang Plain. Our results showed that BC deposition fluxes increased from 0.02 to 0.7 g C/m2.yr during the last 10,000 years. An upward trend was apparent during the last 500 years. Before 1200 cal yr BP, human activities were minor, such that the wetland ecosystem in the Sanjiang Plain before this period may represent the reference conditions that for the recovery of these wetlands. As the human population increased after 1200 cal yr BP, combustion sources changed and residential areas became a major source of BC and PAHs. In this way, the wetland ecosystem gradually became more heavily influenced by human activities.

Monitoring of impact of anthropogenic inputs on water quality of mangrove ecosystem of Uran, Navi Mumbai, west coast of India.

Science.gov (United States)

Pawar, Prabhakar R

2013-10-15

Surface water samples were collected from substations along Sheva creek and Dharamtar creek mangrove ecosystems of Uran (Raigad), Navi Mumbai, west coast of India. Water samples were collected fortnightly from April 2009 to March 2011 during spring low and high tides and were analyzed for pH, Temperature, Turbidity, Total solids (TS), Total dissolved solids (TDS), Total suspended solids (TSS), Dissolved oxygen (DO), Biochemical oxygen demand (BOD), Carbon dioxide (CO2), Chemical oxygen demand (COD), Salinity, Orthophosphate (O-PO4), Nitrite-nitrogen (NO2-N), Nitrate-nitrogen (NO3-N), and Silicates. Variables like pH, turbidity, TDS, salinity, DO, and BOD show seasonal variations. Higher content of O-PO4, NO3-N, and silicates is recorded due to discharge of domestic wastes and sewage, effluents from industries, oil tanking depots and also from maritime activities of Jawaharlal Nehru Port Trust (JNPT), hectic activities of Container Freight Stations (CFS), and other port wastes. This study reveals that water quality from mangrove ecosystems of Uran is deteriorating due to industrial pollution and that mangrove from Uran is facing the threat due to anthropogenic stress. Copyright © 2013 Elsevier Ltd. All rights reserved.

Forests planted for ecosystem restoration or conservation.

Science.gov (United States)

Constance A. Harrington

1999-01-01

Although the phrase, "planting for ecosystem restoration," is of recent origin, many of the earliest large-scale tree plantings were made for what we now refer to as "'restoration" or "conservation" goals. Forest restoration activities may be needed when ecosystems are disturbed by either natural or anthropogenic forces. Disturbances...

The transformation of vegetation vertical zonality affected by anthropogenic impact in East Fennoscandia (Russia)

Science.gov (United States)

Sidorik, Vadim; Miulgauzen, Daria

2017-04-01

Ecosystems of East Fennoscandia have been affected by intensive anthropogenic influence that resulted in their significant transformation. Study of ecosystems in the framework of vegetation vertical zonality disturbance as well as its recovery allows to understand the trends of anthropogenically induced changes. The aim of the present research is the comparative analysis of vegetation vertical zonality of the two uplands in East Fennoscandia which may be considered as unaffected and affected by anthropogenic impact. The objects of key studies carried out in the north-west of Kola Peninsula in the vicinity of the Pechenganikel Mining and Metallurgical Plant are represented by ecosystems of Kalkupya (h 357 m) and Hangaslachdenvara (h 284 m) uplands. They are characterized by the similarity in sequence of altitudinal belts due to the position on the northern taiga - forest-tundra boundary. Plant communities of Kalkupya upland have no visible signs of anthropogenic influence, therefore, they can be considered as model ecosystems of the area. The sequence of altitudinal belts is the following: - up to 200 m - pine subshrub and green moss ("zonal") forest replaced by mixed pine and birch forest near the upper boundary; - 200-300 m - birch crooked subshrub wood; - above 300 m - tundra subshrub and lichen communities. Ecosystems of Hangaslachdenvara upland have been damaged by air pollution (SO2, Ni, Cu emissions) of the Pechenganikel Plant. This impact has led to plant community suppression and formation of barren lands. Besides the soil cover was significantly disturbed, especially upper horizons. Burying of soil profiles, represented by Podzols (WRB, 2015), also manifested itself in the exploited part of the area. The vegetation cover of Hangaslachdenvara upland is the following: - up to 130 m - birch and aspen subshrub and grass forest instead of pine forest ("zonal"); - 130-200 m - barren lands instead of pine forest ("zonal"); - above 200 m - barren lands instead of

Molecular and Microbial Mechanisms Increasing Soil C Storage Under Future Rates of Anthropogenic N Deposition

Energy Technology Data Exchange (ETDEWEB)

Zak, Donald R. [Univ. of Michigan, Ann Arbor, MI (United States)

2017-11-17

A growing body of evidence reveals that anthropogenic N deposition can reduce the microbial decay of plant detritus and increase soil C storage across a wide range of terrestrial ecosystems. This aspect of global change has the potential to constrain the accumulation of anthropogenic CO₂ in the Earth’s atmosphere, and hence slow the pace of climate warming. The molecular and microbial mechanisms underlying this biogeochemical response are not understood, and they are not a component of any coupled climate-biogeochemical model estimating ecosystem C storage, and hence, the future climate of an N-enriched Earth. Here, we report the use of genomic-enabled approaches to identify the molecular underpinnings of the microbial mechanisms leading to greater soil C storage in response to anthropogenic N deposition, thereby enabling us to better anticipate changes in soil C storage.

Past and Future of the Anthropogenic Biosphere

Science.gov (United States)

Ellis, E. C.

2010-12-01

Human populations and their use of land have now transformed most of the terrestrial biosphere into anthropogenic biomes (anthromes). As anthromes have emerged as the dominant global forms of ecological pattern and process, human interactions with terrestrial ecosystems have become a key earth system process, determining the structure and functioning of the biosphere. This presentation explores Ester Boserup’s land use intensification theories as models for understanding the emergence and dynamics of anthromes and their ecological processes, including their biogeochemistry and community structure, from the mostly wild biosphere of the Holocene to the primarily anthropogenic biosphere of the present and future. Existing global models and data for human population growth and land use over the Holocene differ in their portrayal of the global transition to a mostly anthropogenic biosphere. Yet there is little doubt that human populations have continued to grow over the long term and that anthromes have been increasingly important global ecological systems for millennia. This is conclusive evidence that human interactions with ecosystems can be sustained over the long-term, albeit under conditions that may no longer be realizable by either Earth or human systems. The classic Malthusian paradigm, in which human population growth outstrips natural resources leading to population collapse is unsupported by historical observations at global scale. Boserupian intensification is the better model, providing a robust theoretical foundation in which socio-ecological systems evolve as human populations increase, towards increasingly efficient use of limiting natural resources and enhanced production of anthropogenic ecological services such as food. This is not a story of technical advance, but rather of the forced adoption of ever more energy-intensive technical solutions in support of ever increasing population demands. And it does explain historical changes in the biosphere

Natural and anthropogenic hydrocarbons in the White sea ecosystem

International Nuclear Information System (INIS)

Nemirovskaya, I.; Shevchenko, V.; Bogunov, A.

2006-01-01

An investigation of aliphatic hydrocarbons (AHC) and polycyclic aromatic hydrocarbons (PAH) concentrations in the White Sea was presented. The study was conducted to determine natural and anthropogenic hydrocarbon (HC) concentrations in order to aid in future zoning plans. Hydrocarbons were extracted from samples of aerosols, ice, water, particulate matter, phyto- and zooplankton, and bottom sediments. Results of the study suggested that HC concentrations in aerosols above the White Sea were lower than in marine aerosols above the southeastern Atlantic and lower than Alkane concentrations in aerosols in the Mediterranean Sea. A study of PAH behaviour in Northern Dvina estuaries showed that the submicron fractions contained light polyarenes. Particulate matter collected in sedimentation traps was enriched in phenanthrene, fluoranthene, and pyrene. Aliphatic HC enrichment was due to the presence of phytoplankton and other microorganisms. Between 54 per cent and 85 per cent of initial organic matter was consumed during diagenesis in the bottom sediments, indicating a high rate of HC transformation. It was suggested that the majority of oil HC transported with river water is precipitated. Fluoranthene was the dominant PAH in the study, and was assumed to be caused by natural transformation of PAH composition during distant atmospheric transport. Pyrogenic contamination of the bottom sediments was attributed to an aluminium plant. It was concluded that the detection of significant amounts of HC is not direct evidence of their anthropogenic origins. 31 refs., 3 tabs., 7 figs

Causes and consequences of ecosystem service regionalization in a coastal suburban watershed

Science.gov (United States)

Wollheim, Wilfred M.; Mark B. Green,; Pellerin, Brian A.; Morse, Nathaniel B.; Hopkinson, Charles S.

2015-01-01

The demand for ecosystem services and the ability of natural ecosystems to provide those services evolve over time as population, land use, and management practices change. Regionalization of ecosystem service activity, or the expansion of the area providing ecosystem services to a population, is a common response in densely populated coastal regions, with important consequences for watershed water and nitrogen (N) fluxes to the coastal zone. We link biophysical and historical information to explore the causes and consequences of change in ecosystem service activity—focusing on water provisioning and N regulation—from 1850 to 2010 in a coastal suburban watershed, the Ipswich River watershed in northeastern Massachusetts, USA. Net interbasin water transfers started in the late 1800s due to regionalization of water supply for use by larger populations living outside the Ipswich watershed boundaries, reaching a peak in the mid-1980s. Over much of the twentieth century, about 20 % of river runoff was diverted from reaching the estuary, with greater proportions during drought years. Ongoing regionalization of water supply has contributed to recent declines in diversions, influenced by socioecological feedbacks resulting from the river drying and fish kills. Similarly, the N budget has been greatly perturbed since the suburban era began in the 1950s due to food and lawn fertilizer imports and human waste release. However, natural ecosystems are able to remove most of this anthropogenic N, mitigating impacts on the coastal zone. We propose a conceptual model whereby the amount and type of ecosystem services provided by coastal watersheds in urban regions expand and contract over time as regional population expands and ecosystem services are regionalized. We hypothesize that suburban watersheds can be hotspots of ecosystem service sources because they retain sufficient ecosystem function to still produce services that meet increasing demand from the local population

Nitrogen spiraling in stream ecosystems spanning a gradient of chronic nitrogen loading

OpenAIRE

Earl, Stevan Ross

2004-01-01

This dissertation is a study of the relationships between nitrogen (N) availability and spiraling (the paired processes of nutrient cycling and advective transport) in stream ecosystems. Anthropogenic activities have greatly increased rates of N loading to aquatic ecosystems. However, streams may be important sites for retention, removal, and transformation of N. In order to identify controls on NO3-N spiraling in anthropogenically impacted streams, I examined relationships among NO3-N spi...

Anthropogenic transformation of the terrestrial biosphere.

Science.gov (United States)

Ellis, Erle C

2011-03-13

Human populations and their use of land have transformed most of the terrestrial biosphere into anthropogenic biomes (anthromes), causing a variety of novel ecological patterns and processes to emerge. To assess whether human populations and their use of land have directly altered the terrestrial biosphere sufficiently to indicate that the Earth system has entered a new geological epoch, spatially explicit global estimates of human populations and their use of land were analysed across the Holocene for their potential to induce irreversible novel transformation of the terrestrial biosphere. Human alteration of the terrestrial biosphere has been significant for more than 8000 years. However, only in the past century has the majority of the terrestrial biosphere been transformed into intensively used anthromes with predominantly novel anthropogenic ecological processes. At present, even were human populations to decline substantially or use of land become far more efficient, the current global extent, duration, type and intensity of human transformation of ecosystems have already irreversibly altered the terrestrial biosphere at levels sufficient to leave an unambiguous geological record differing substantially from that of the Holocene or any prior epoch. It remains to be seen whether the anthropogenic biosphere will be sustained and continue to evolve.

Aquatic noise pollution: implications for individuals, populations, and ecosystems.

Science.gov (United States)

Kunc, Hansjoerg P; McLaughlin, Kirsty Elizabeth; Schmidt, Rouven

2016-08-17

Anthropogenically driven environmental changes affect our planet at an unprecedented scale and are considered to be a key threat to biodiversity. According to the World Health Organization, anthropogenic noise is one of the most hazardous forms of anthropogenically driven environmental change and is recognized as a major global pollutant. However, crucial advances in the rapidly emerging research on noise pollution focus exclusively on single aspects of noise pollution, e.g. on behaviour, physiology, terrestrial ecosystems, or on certain taxa. Given that more than two-thirds of our planet is covered with water, there is a pressing need to get a holistic understanding of the effects of anthropogenic noise in aquatic ecosystems. We found experimental evidence for negative effects of anthropogenic noise on an individual's development, physiology, and/or behaviour in both invertebrates and vertebrates. We also found that species differ in their response to noise, and highlight the potential underlying mechanisms for these differences. Finally, we point out challenges in the study of aquatic noise pollution and provide directions for future research, which will enhance our understanding of this globally present pollutant. © 2016 The Author(s).

Simulations of the global carbon cycle and anthropogenic CO{sub 2} transient. Annual report

Energy Technology Data Exchange (ETDEWEB)

Sarmiento, J.L.

1994-07-01

This research focuses on improving the understanding of the anthropogenic carbon dioxide transient using observations and models of the past and present. In addition, an attempt is made to develop an ability to predict the future of the carbon cycle in response to continued anthropogenic perturbations and climate change. Three aspects of the anthropogenic carbon budget were investigated: (1) the globally integrated budget at the present time; (2) the time history of the carbon budget; and (3) the spatial distribution of carbon fluxes. One of the major activities of this study was the participation in the model comparison study of Enting, et al. [1994] carried out in preparation for the IPCC 1994 report.

Temporal development of coastal ecosystems in the Baltic Sea over the past two decades

DEFF Research Database (Denmark)

Olsson, Jens; Tomczak, Maciej; Ojaveer, Henn

2015-01-01

Coastal areas are among the most biologically productive aquatic systems worldwide, but face strong and variable anthropogenic pressures. Few studies have, however, addressed the temporal development of coastal ecosystems in an integrated context. This study represents an assessment of the develo...... in the capacity of currently available monitoring data to support integrated assessments and the implementation of an integrated ecosystem-based approach to the management of the Baltic Sea coastal ecosystems......Coastal areas are among the most biologically productive aquatic systems worldwide, but face strong and variable anthropogenic pressures. Few studies have, however, addressed the temporal development of coastal ecosystems in an integrated context. This study represents an assessment...

The effects of acid perturbation on a controlled ecosystem

Energy Technology Data Exchange (ETDEWEB)

Kollig, H.P.; Hall, T.L.

1982-02-01

Duplicate, 8-compartment, continuous-flow microcosms were used to study the effects of acid addition on community function, algal community structure, and degradation of a plasticizer, diethyl phthalate. Inputs of HCl decreased the alkalinity (measured as CaCO/sub 3/) from 25 to 8 mgl/sup -1/, creating diurnal H/sup +/ activity curves that indicated that the ecosystem was being severely stressed. Removal of excess acid was accompanied by a return to a normal diurnal pH cycle. Nutrient concentrations and 0/sub 2/ production did not give a definite indication of stress resulting from the addition of acid. Algal community structure and total biomass were not affected by acid inputs. Also, degradation rates of diethyl phtalate by the aquatic bacteria were similar for the control and the acid-stressed systems. These studies indicate that acid inputs can significantly disrupt normal ecosystem function, such as diurnal pH cycling, without having a measurable impact on other parameters usually monitored in aquatic ecosystems.

Coral Ecosystem Resilience, Conservation and Management on the Reefs of Jamaica in the Face of Anthropogenic Activities and Climate Change

Directory of Open Access Journals (Sweden)

M. James C. Crabbe

2010-06-01

Full Text Available Knowledge of factors that are important in reef resilience and integrity help us understand how reef ecosystems react following major anthropogenic and environmental disturbances. The North Jamaican fringing reefs have shown some recent resilience to acute disturbances from hurricanes and bleaching, in addition to the recurring chronic stressors of over-fishing and land development. Factors that can improve coral reef resilience are reviewed, and reef rugosity is shown to correlate with coral cover and growth, particularly for branching Acropora species. The biodiversity index for the Jamaican reefs was lowered after the 2005 mass bleaching event, as were the numbers of coral colonies, but both had recovered by 2009. The importance of coastal zone reef management strategies and the economic value of reefs are discussed, and a protocol is suggested for future management of Jamaican reefs.

Estimation of lead sources in a Japanese cedar ecosystem using stable isotope analysis

International Nuclear Information System (INIS)

Itoh, Yuko; Noguchi, Kyotaro; Takahashi, Masamichi; Okamoto, Toru; Yoshinaga, Shuichiro

2007-01-01

Anthropogenic Pb affects the environment worldwide. To understand its effect on forest ecosystem, Pb isotope ratios were determined in precipitation, various components of vegetation, the forest floor, soil and parent material in a Japanese cedar (Cryptomeria japonica D. Don) forest stand. The average 206 Pb/ 207 Pb ratio in bulk precipitation was 1.14 ± 0.01 (mean ± SD), whereas that in the subsoil (20-130 cm) was 1.18 ± 0.01. Intermediate ratios ranging from 1.15 to 1.16 were observed in the vegetation, the forest floor, and the surface soil (0-10 cm). Using the 206 Pb/ 207 Pb ratios, the contribution of anthropogenic sources to Pb accumulated in the forest were estimated by the simple binary mixing model. Sixty-two percent of the Pb in the forest floor, 71% in the vegetation, and 55% in the surface soil (0-10 cm) originated from anthropogenic sources, but only 16% in the sub-surface soil (10-20 cm) was anthropogenic. These results suggest that internal Pb cycling occurs mainly between surface soil and vegetation in a Japanese cedar ecosystem, and that anthropogenic Pb strongly influences Pb cycling. Although the Japanese cedar ecosystem has a shallow forest floor, very little atmospherically derived Pb migrated downward over 10 cm in depth

What is Novel About Novel Ecosystems: Managing Change in an Ever-Changing World

Science.gov (United States)

Truitt, Amy M.; Granek, Elise F.; Duveneck, Matthew J.; Goldsmith, Kaitlin A.; Jordan, Meredith P.; Yazzie, Kimberly C.

2015-06-01

Influenced by natural climatic, geological, and evolutionary changes, landscapes and the ecosystems within are continuously changing. In addition to these natural pressures, anthropogenic drivers have increasingly influenced ecosystems. Whether affected by natural or anthropogenic processes, ecosystems, ecological communities, and ecosystem functioning are dynamic and can lead to "novel" or "emerging" ecosystems. Current literature identifies several definitions of these ecosystems but lacks an unambiguous definition and framework for categorizing what constitutes a novel ecosystem and for informing decisions around best management practices. Here we explore the various definitions used for novel ecosystems, present an unambiguous definition, and propose a framework for identifying the most appropriate management option. We identify and discuss three approaches for managing novel ecosystems: managing against, tolerating, and managing for these systems, and we provide real-world examples of each approach. We suggest that this framework will allow managers to make thoughtful decisions about which strategy is most appropriate for each unique situation, to determine whether the strategy is working, and to facilitate decision-making when it is time to modify the management approach.

Characterization of dissolved organic matter in a coral reef ecosystem subjected to anthropogenic pressures (La Réunion Island, Indian Ocean) using multi-dimensional fluorescence spectroscopy.

Science.gov (United States)

Tedetti, Marc; Cuet, Pascale; Guigue, Catherine; Goutx, Madeleine

2011-05-01

La Saline fringing reef is the most important coral reef complex of La Réunion Island (southwestern Indian Ocean; 21°07'S, 55°32'E). This ecosystem is subjected to anthropogenic pressures through river inputs and submarine groundwater discharge (SGD). The goal of this study was to characterize the pool of fluorescent dissolved organic matter (FDOM) in different water bodies of La Saline fringing reef ecosystem using excitation-emission matrix (EEM) spectrofluorometry. From EEMs, we identified the different fluorophores by the peak picking technique and determined two fluorescence indices issued from the literature: the humification index (HIX) and the biological index (BIX). The main known fluorophores were present within the sample set: humic-like A, humic-like C, marine humic-like M, tryptophan-like T1 and T2, and tyrosine-like B1 and B2. In some samples, unknown fluorophores ("U") were also detected. The surface oceanic waters located beyond the reef front displayed a typical oligotrophic marine signature, with a dominance of autochthonous/biological material (presence of peaks: T1>B1>A>T2>M>C; HIX: 0.9±0.4; BIX: 2.3±1.1). In the reef waters, the autochthonous/biological fingerprint also dominated even though the content in humic substances was higher (same relative distribution of peaks; HIX: 1.6±0.6; BIX: 1.0±0.1). Sedimentary and volcanic SGD showed very different patterns with a strong terrestrial source for the former (A>T1>C>B1 and A>C>B1; HIX: 9.8±2.0; BIX: 0.8±0.0) and a weak terrestrial source for the latter (A>B1>U3>B2>C and A>U4>C; HIX: 2.4±0.3; BIX: 0.9±0.0). In the Hermitage River, both humic substances and protein-like material were abundant (T1>A>U5>B1>C>B2; HIX: 2.3; BIX: 1.4). We provide evidences for the presence of anthropogenic DOM in some of these water bodies. Some oceanic samples (presence of peaks U1 and U2) were likely contaminated by oil-derived PAHs from ships navigating around the reef front, whereas the Hermitage River was

Gulf of Mexico Ecosystem Status Report

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Gulf of Mexico is one of the most ecologically and economically valuable marine ecosystems in the world and is affected by a variety of natural and anthropogenic...

Response diversity determines the resilience of ecosystems to environmental change.

Science.gov (United States)

Mori, Akira S; Furukawa, Takuya; Sasaki, Takehiro

2013-05-01

A growing body of evidence highlights the importance of biodiversity for ecosystem stability and the maintenance of optimal ecosystem functionality. Conservation measures are thus essential to safeguard the ecosystem services that biodiversity provides and human society needs. Current anthropogenic threats may lead to detrimental (and perhaps irreversible) ecosystem degradation, providing strong motivation to evaluate the response of ecological communities to various anthropogenic pressures. In particular, ecosystem functions that sustain key ecosystem services should be identified and prioritized for conservation action. Traditional diversity measures (e.g. 'species richness') may not adequately capture the aspects of biodiversity most relevant to ecosystem stability and functionality, but several new concepts may be more appropriate. These include 'response diversity', describing the variation of responses to environmental change among species of a particular community. Response diversity may also be a key determinant of ecosystem resilience in the face of anthropogenic pressures and environmental uncertainty. However, current understanding of response diversity is poor, and we see an urgent need to disentangle the conceptual strands that pervade studies of the relationship between biodiversity and ecosystem functioning. Our review clarifies the links between response diversity and the maintenance of ecosystem functionality by focusing on the insurance hypothesis of biodiversity and the concept of functional redundancy. We provide a conceptual model to describe how loss of response diversity may cause ecosystem degradation through decreased ecosystem resilience. We explicitly explain how response diversity contributes to functional compensation and to spatio-temporal complementarity among species, leading to long-term maintenance of ecosystem multifunctionality. Recent quantitative studies suggest that traditional diversity measures may often be uncoupled from

Plankton food-web functioning in anthropogenically impacted coastal waters (SW Mediterranean Sea): An ecological network analysis

Science.gov (United States)

Meddeb, Marouan; Grami, Boutheïna; Chaalali, Aurélie; Haraldsson, Matilda; Niquil, Nathalie; Pringault, Olivier; Sakka Hlaili, Asma

2018-03-01

The study is the first attempt to (i) model spring food webs in three SW Mediterranean ecosystems which are under different anthropogenic pressures and (ii) to project the consequence of this stress on their function. Linear inverse models were built using the Monte Carlo method coupled with Markov Chains to characterize the food-web status of the Lagoon, the Channel (inshore waters under high eutrophication and chemical contamination) and the Bay of Bizerte (offshore waters under less anthropogenic pressure). Ecological network analysis was used for the description of structural and functional properties of each food web and for inter-ecosystem comparisons. Our results showed that more carbon was produced by phytoplankton in the inshore waters (966-1234 mg C m-2 d-1) compared to the Bay (727 mg C m-2 d-1). The total ecosystem carbon inputs into the three food webs was supported by high primary production, which was mainly due to >10 μm algae. However, the three carbon pathways were characterized by low detritivory and a high herbivory which was mainly assigned to protozooplankton. This latter was efficient in channelling biogenic carbon. In the Lagoon and the Channel, foods webs acted almost as a multivorous structure with a tendency towards herbivorous one, whereas in the Bay the herbivorous pathway was more dominant. Ecological indices revealed that the Lagoon and the Channel food webs/systems had high total system throughput and thus were more active than the Bay. The Bay food web, which had a high relative ascendency value, was more organized and specialized. This inter-ecosystem difference could be due to the varying levels of anthropogenic impact among sites. Indeed, the low value of Finn's cycling index indicated that the three systems are disturbed, but the Lagoon and the Channel, with low average path lengths, appeared to be more stressed, as both sites have undergone higher chemical pollution and nutrient loading. This study shows that ecosystem models

Anthropogenic infrastructure as a component of urbogeosystems

Directory of Open Access Journals (Sweden)

Oleksii Chuiev

2017-11-01

Full Text Available This article deals with the definition of the concept of "anthropogenic infrastructure" and attempts to find its place in the structure of urbogeosystems. The concept itself can not be called new, as many foreign authors have already used it, but the final definition never happened. The reasons why city studies are becoming more relevant in the face of ever-accelerating urbanization are briefly presented. Prerequisites for the emergence of the urban environment and approaches to its study are given. A special attention is paid to the consideration of urbosystems and their component structure. The main four components are described, which include the technosphere, biosphere, population and abiotic nature. The causes of the appearance of urban ecosystems and their specific features are analyzed. Based on the deficiencies of the "Urbosphere", "Urbosystem" and "Urboecosystem", the notion of "Urbogeosystem" is formed once again. Since architectural and construction objects are key components of such systems, their integration into anthropogenic infrastructure allows us to operate with a more general concept. Functional zones of the city, which are part of the anthropogenic infrastructure, are described. These include residential, industrial, forest and park areas. Examples of the use and functioning of each of the zones are given. An attempt has been made to estimate the boundaries of urbogeosystems. The existing approaches to the classification of anthropogenic infrastructure are analyzed. For one of them, it is advisable to allocate separately "hard" and "soft" infrastructure by the nature of the tasks of society, which they are called upon to satisfy. An alternative approach is to divide the anthropogenic infrastructure into "human" and "physical" ones. If the first satisfies the socio-cultural needs of people, the second is used for production, development, establishment of communications, transportation. It is proved why it is expedient to

Life around the North Water ecosystem

DEFF Research Database (Denmark)

Hastrup, Kirsten Blinkenberg; Andersen, Astrid Oberborbeck; Grønnow, Bjarne

2018-01-01

The formation of the North Water in Smith Sound about 4500 years ago, as evidenced by the establishment of bird colonies and human presence, also initiated a long-term anthropogenic agent as part of this High Arctic ecosystem. Different epochs have influenced the human occupation in the area: imm...... ramifications that extend beyond the High Arctic, and include human activity. The challenge is to determine what is internal and what is external to an ecosystem....

Assessing confidence in management adaptation approaches for climate-sensitive ecosystems

International Nuclear Information System (INIS)

West, J M; Julius, S H; Weaver, C P

2012-01-01

A number of options are available for adapting ecosystem management to improve resilience in the face of climatic changes. However, uncertainty exists as to the effectiveness of these options. A report prepared for the US Climate Change Science Program reviewed adaptation options for a range of federally managed systems in the United States. The report included a qualitative uncertainty analysis of conceptual approaches to adaptation derived from the review. The approaches included reducing anthropogenic stressors, protecting key ecosystem features, maintaining representation, replicating, restoring, identifying refugia and relocating organisms. The results showed that the expert teams had the greatest scientific confidence in adaptation options that reduce anthropogenic stresses. Confidence in other approaches was lower because of gaps in understanding of ecosystem function, climate change impacts on ecosystems, and management effectiveness. This letter discusses insights gained from the confidence exercise and proposes strategies for improving future assessments of confidence for management adaptations to climate change. (letter)

Nitrogen Dynamics in European Forest Ecosystems: Considerations regarding Anthropogenic Nitrogen Depositions

OpenAIRE

Agren, G.I.; Kauppi, P.

1983-01-01

This study deals with the nutrient cycle of forest ecosystems over large geographic regions in Europe as affected by nitrogen deposition. The view is taken that the nitrogen cycle of a forest ecosystem has a maximum capacity for circulating nitrogen. Two different cases are defined: case (1) in which the nutrient cycle functions below its maximum capacity, and case (2) in which the circulation operates at the maximum level.

First evidence of agro-pastoral farming and anthropogenic impact in the Taman Peninsula, Russia

Science.gov (United States)

Kaniewski, David; Giaime, Matthieu; Marriner, Nick; Morhange, Christophe; Otto, Thierry; Porotov, Alexey V.; Van Campo, Elise

2015-04-01

Debate on the complex coevolution that has shaped interactions between forested ecosystems and humans through constantly evolving land-use practices over the past millennia has long been centered on the Mediterranean because this area is seen as the cradle for the birth and growth of agricultural activities. Here, we argue that the transition from hunting-gathering by Mesolithic foragers to the food-producing economy of Neolithic farmers was a main trigger of biological changes not only in the Mediterranean but also in the Black Sea and Azov Sea coasts through woodcutting, herding, fire and agriculture. Although the ecological erosion was clearly focused on forested ecosystems, this process seems to have fostered an increased biodiversity. We show, by focusing on the fertile coast of the Azov Sea, that (i) the first evidence of cereal cultivation and human-induced fire occurred in southern Russia 7000 years ago; (ii) the early development of agriculture was a major but discontinuous process; (iii) the coastal ecosystems were rapidly disturbed by anthropogenic activities; and (iv) the Neolithic was a critical threshold for the forested ecosystems of the coastal area. The impact of early anthropogenic pressures seems to have been largely neglected or underestimated for the period encompassing the Neolithic cultural phase.

Impacts of aerosol lead to natural ecosystems

International Nuclear Information System (INIS)

Murozumi, Masayo; Nakamura, Seiji; Yoshida, Katsumi

1982-01-01

Impacts of aerosol lead have changed the concentration and isotopic ratios of the element circulating in remote ecosystems in the Hidaka and Tarumae mountains. Concentrations of lead in successive each 10 years ring veneer of Cercidiphyllum Japonica show that amount of the element residing on the bark and supwood layers has increased by a factor of 2 or more in comparison with that of the core part. The isotopic ratios of lead in the basement rocks and soils under the ecosystems converge to a certain narrow spot along the isochron Iine of the element, and distinguish their geochronogical characteristics from other leads of different sources. In these ecosystems, however, the lead isotopic ratios of materials exposed to the atmosphere are similar to those of foreign and anthropogenic aerosol lead but are evidently dissimilar to those of the rocks and soils. Furthermore, the lead isotopic ratios in yearly ring veneers of Ceridiphyllum Japonica and Ostrya Japonica show a certain differentiation towards the bark from the core, i.e., an approach to those of anthropogenic aerosol lead from those of the basement rocks and soils, as listed in Table 7. The lead burden per hectare in these remote ecosystems has increased to 4 g by the impact of 2 g of aerosol lead. (author)

Functional changes in littoral macroinvertebrate communities in response to watershed-level anthropogenic stress.

Directory of Open Access Journals (Sweden)

Katya E Kovalenko

Full Text Available Watershed-scale anthropogenic stressors have profound effects on aquatic communities. Although several functional traits of stream macroinvertebrates change predictably in response to land development and urbanization, little is known about macroinvertebrate functional responses in lakes. We assessed functional community structure, functional diversity (Rao's quadratic entropy and voltinism in macroinvertebrate communities sampled across the full gradient of anthropogenic stress in Laurentian Great Lakes coastal wetlands. Functional diversity and voltinism significantly decreased with increasing development, whereas agriculture had smaller or non-significant effects. Functional community structure was affected by watershed-scale development, as demonstrated by an ordination analysis followed by regression. Because functional community structure affects energy flow and ecosystem function, and functional diversity is known to have important implications for ecosystem resilience to further environmental change, these results highlight the necessity of finding ways to remediate or at least ameliorate these effects.

Chaotic behavior of a three-species Beddington-type system with impulsive perturbations

International Nuclear Information System (INIS)

Wang Weiming; Wang Hailing; Li Zhenqing

2008-01-01

In this paper, a three-species food chain system with Beddington-type functional response and impulsive perturbations on the top predator is established. Subsequently, using Maple, the influence of the impulsive perturbations on the inherent oscillation is investigated, which shows rich dynamics. The work is useful for studying the dynamic and complexity of ecosystems

Anthropogenic impact on diazotrophic diversity in the mangrove rhizosphere revealed by nifH pyrosequencing.

Science.gov (United States)

Jing, Hongmei; Xia, Xiaomin; Liu, Hongbin; Zhou, Zhi; Wu, Chen; Nagarajan, Sanjay

2015-01-01

Diazotrophs in the mangrove rhizosphere play a major role in providing new nitrogen to the mangrove ecosystem and their composition and activity are strongly influenced by anthropogenic activity and ecological conditions. In this study, the diversity of the diazotroph communities in the rhizosphere sediment of five tropical mangrove sites with different levels of pollution along the north and south coastline of Singapore were studied by pyrosequencing of the nifH gene. Bioinformatics analysis revealed that in all the studied locations, the diazotroph communities comprised mainly of members of the diazotrophic cluster I and cluster III. The detected cluster III diazotrophs, which were composed entirely of sulfate-reducing bacteria, were more abundant in the less polluted locations. The metabolic capacities of these diazotrophs indicate the potential for bioremediation and resiliency of the ecosystem to anthropogenic impact. In heavily polluted locations, the diazotrophic community structures were markedly different and the diversity of species was significantly reduced when compared with those in a pristine location. This, together with the increased abundance of Marinobacterium, which is a bioindicator of pollution, suggests that anthropogenic activity has a negative impact on the genetic diversity of diazotrophs in the mangrove rhizosphere.

Anthropogenic climate change affects meteorological drought risk in Europe

International Nuclear Information System (INIS)

Gudmundsson, L; Seneviratne, S I

2016-01-01

Drought constitutes a significant natural hazard in Europe, impacting societies and ecosystems across the continent. Climate model simulations with increasing greenhouse gas concentrations project increased drought risk in southern Europe, and on the other hand decreased drought risk in the north. Observed changes in water balance components and drought indicators resemble the projected pattern. However, assessments of possible causes of the reported regional changes have so far been inconclusive. Here we investigate whether anthropogenic emissions have altered past and present meteorological (precipitation) drought risk. For doing so we first estimate the magnitude of 20 year return period drought years that would occur without anthropogenic effects on the climate. Subsequently we quantify to which degree the occurrence probability, i.e. the risk, of these years has changed if anthropogenic climate change is accounted for. Both an observational and a climate model-based assessment suggest that it is >95% likely that human emissions have increased the probability of drought years in the Mediterranean, whereas it is >95% likely that the probability of dry years has decreased in northern Europe. In central Europe the evidence is inconclusive. The results highlight that anthropogenic climate change has already increased drought risk in southern Europe, stressing the need to develop efficient mitigation measures. (letter)

Emissions of biogenic VOC from forest ecosystems in central Europe: Estimation and comparison with anthropogenic emission inventory

International Nuclear Information System (INIS)

Zemankova, Katerina; Brechler, Josef

2010-01-01

This paper describes a method of estimating emission fluxes of biogenic volatile organic compounds (BVOCs) based on the approach proposed by and the high-resolution Corine land-cover 2000 database (1 x 1 km resolution). The computed emission fluxes for the Czech Republic (selected for analysis as being representative of a heavily cultivated, central European country) are compared with anthropogenic emissions, both for the entire country and for individual administrative regions. In some regions, BVOC emissions are as high as anthropogenic emissions; however, in most regions the BVOC emissions are approximately 50% of the anthropogenic emissions. The yearly course of BVOC emissions (represented by monoterpenes and isoprene) is presented, along with the spatial distribution of annual mean values. Differences in emission distributions during winter (January) and summer (June) are also considered. - The amount of the biogenic VOCs emitted over the central Europe is comparable with the anthropogenic VOC emissions from this region.

β-Diversity, Community Assembly, and Ecosystem Functioning.

Science.gov (United States)

Mori, Akira S; Isbell, Forest; Seidl, Rupert

2018-05-25

Evidence is increasing for positive effects of α-diversity on ecosystem functioning. We highlight here the crucial role of β-diversity - a hitherto underexplored facet of biodiversity - for a better process-level understanding of biodiversity change and its consequences for ecosystems. A focus on β-diversity has the potential to improve predictions of natural and anthropogenic influences on diversity and ecosystem functioning. However, linking the causes and consequences of biodiversity change is complex because species assemblages in nature are shaped by many factors simultaneously, including disturbance, environmental heterogeneity, deterministic niche factors, and stochasticity. Because variability and change are ubiquitous in ecosystems, acknowledging these inherent properties of nature is an essential step for further advancing scientific knowledge of biodiversity-ecosystem functioning in theory and practice. Copyright © 2018 Elsevier Ltd. All rights reserved.

Oceanic nitrogen cycling and N2O flux perturbations in the Anthropocene

Science.gov (United States)

Landolfi, A.; Somes, C. J.; Koeve, W.; Zamora, L. M.; Oschlies, A.

2017-08-01

There is currently no consensus on how humans are affecting the marine nitrogen (N) cycle, which limits marine biological production and CO2 uptake. Anthropogenic changes in ocean warming, deoxygenation, and atmospheric N deposition can all individually affect the marine N cycle and the oceanic production of the greenhouse gas nitrous oxide (N2O). However, the combined effect of these perturbations on marine N cycling, ocean productivity, and marine N2O production is poorly understood. Here we use an Earth system model of intermediate complexity to investigate the combined effects of estimated 21st century CO2 atmospheric forcing and atmospheric N deposition. Our simulations suggest that anthropogenic perturbations cause only a small imbalance to the N cycle relative to preindustrial conditions (˜+5 Tg N y-1 in 2100). More N loss from water column denitrification in expanded oxygen minimum zones (OMZs) is counteracted by less benthic denitrification, due to the stratification-induced reduction in organic matter export. The larger atmospheric N load is offset by reduced N inputs by marine N2 fixation. Our model predicts a decline in oceanic N2O emissions by 2100. This is induced by the decrease in organic matter export and associated N2O production and by the anthropogenically driven changes in ocean circulation and atmospheric N2O concentrations. After comprehensively accounting for a series of complex physical-biogeochemical interactions, this study suggests that N flux imbalances are limited by biogeochemical feedbacks that help stabilize the marine N inventory against anthropogenic changes. These findings support the hypothesis that strong negative feedbacks regulate the marine N inventory on centennial time scales.

Simulated anthropogenic CO2 storage and acidification of the Mediterranean Sea

Directory of Open Access Journals (Sweden)

J. Palmiéri

2015-02-01

Full Text Available Constraints on the Mediterranean Sea's storage of anthropogenic CO2 are limited, coming only from data-based approaches that disagree by more than a factor of two. Here we simulate this marginal sea's anthropogenic carbon storage by applying a perturbation approach in a high-resolution regional model. Our model simulates that, between 1800 and 2001, basin-wide CO2 storage by the Mediterranean Sea has increased by 1.0 Pg C, a lower limit based on the model's weak deep-water ventilation, as revealed by evaluation with CFC-12. Furthermore, by testing a data-based approach (transit time distribution in our model, comparing simulated anthropogenic CO2 to values computed from simulated CFC-12 and physical variables, we conclude that the associated basin-wide storage of 1.7 Pg, published previously, must be an upper bound. Out of the total simulated storage of 1.0 Pg C, 75% comes from the air–sea flux into the Mediterranean Sea and 25% comes from net transport from the Atlantic across the Strait of Gibraltar. Sensitivity tests indicate that the Mediterranean Sea's higher total alkalinity, relative to the global-ocean mean, enhances the Mediterranean's total inventory of anthropogenic carbon by 10%. Yet the corresponding average anthropogenic change in surface pH does not differ significantly from the global-ocean average, despite higher total alkalinity. In Mediterranean deep waters, the pH change is estimated to be between −0.005 and −0.06 pH units.

The biodiversity-dependent ecosystem service debt.

Science.gov (United States)

Isbell, Forest; Tilman, David; Polasky, Stephen; Loreau, Michel

2015-02-01

Habitat destruction is driving biodiversity loss in remaining ecosystems, and ecosystem functioning and services often directly depend on biodiversity. Thus, biodiversity loss is likely creating an ecosystem service debt: a gradual loss of biodiversity-dependent benefits that people obtain from remaining fragments of natural ecosystems. Here, we develop an approach for quantifying ecosystem service debts, and illustrate its use to estimate how one anthropogenic driver, habitat destruction, could indirectly diminish one ecosystem service, carbon storage, by creating an extinction debt. We estimate that c. 2-21 Pg C could be gradually emitted globally in remaining ecosystem fragments because of plant species loss caused by nearby habitat destruction. The wide range for this estimate reflects substantial uncertainties in how many plant species will be lost, how much species loss will impact ecosystem functioning and whether plant species loss will decrease soil carbon. Our exploratory analysis suggests that biodiversity-dependent ecosystem service debts can be globally substantial, even when locally small, if they occur diffusely across vast areas of remaining ecosystems. There is substantial value in conserving not only the quantity (area), but also the quality (biodiversity) of natural ecosystems for the sustainable provision of ecosystem services. © 2014 John Wiley & Sons Ltd/CNRS.

Retrospective analysis of bottlenose dolphin foraging: a legacy of anthropogenic ecosystem disturbance

Science.gov (United States)

Rossman, Sam; Barros, Nélio B.; Ostrom, Peggy H.; Stricker, Craig A.; Hohn, Aleta A.; Gandhi, Hasand; Wells, Randall S.

2013-01-01

We used stable isotope analysis to investigate the foraging ecology of coastal bottlenose dolphins (Tursiops truncatus) in relation to a series of anthropogenic disturbances. We first demonstrated that stable isotopes are a faithful indicator of habitat use by comparing muscle isotope values to behavioral foraging data from the same individuals. δ13C values increased, while δ34S and δ15N values decreased with the percentage of feeding observations in seagrass habitat. We then utilized stable isotope values of muscle to assess temporal variation in foraging habitat from 1991 to 2010 and collagen from tooth crown tips to assess the time period 1944 to 2007. From 1991 to 2010, δ13C values of muscle decreased while δ34S values increased indicating reduced utilization of seagrass habitat. From 1944 to 1989 δ13C values of the crown tip declined significantly, likely due to a reduction in the coverage of seagrass habitat and δ15N values significantly increased, a trend we attribute to nutrient loading from a rapidly increasing human population. Our results demonstrate the utility of using marine mammal foraging habits to retrospectively assess the extent to which anthropogenic disturbance impacts coastal food webs.

The unnatural history of Kāne‘ohe Bay: coral reef resilience in the face of centuries of anthropogenic impacts

Directory of Open Access Journals (Sweden)

Keisha D. Bahr

2015-05-01

Full Text Available Kāneʻohe Bay, which is located on the on the NE coast of Oʻahu, Hawaiʻi, represents one of the most intensively studied estuarine coral reef ecosystems in the world. Despite a long history of anthropogenic disturbance, from early settlement to post European contact, the coral reef ecosystem of Kāneʻohe Bay appears to be in better condition in comparison to other reefs around the world. The island of Moku o Loʻe (Coconut Island in the southern region of the bay became home to the Hawaiʻi Institute of Marine Biology in 1947, where researchers have since documented the various aspects of the unique physical, chemical, and biological features of this coral reef ecosystem. The first human contact by voyaging Polynesians occurred at least 700 years ago. By A.D. 1250 Polynesians voyagers had settled inhabitable islands in the region which led to development of an intensive agricultural, fish pond and ocean resource system that supported a large human population. Anthropogenic disturbance initially involved clearing of land for agriculture, intentional or accidental introduction of alien species, modification of streams to supply water for taro culture, and construction of massive shoreline fish pond enclosures and extensive terraces in the valleys that were used for taro culture. The arrival by the first Europeans in 1778 led to further introductions of plants and animals that radically changed the landscape. Subsequent development of a plantation agricultural system led to increased human immigration, population growth and an end to traditional land and water management practices. The reefs were devastated by extensive dredge and fill operations as well as rapid growth of human population, which led to extensive urbanization of the watershed. By the 1960’s the bay was severely impacted by increased sewage discharge along with increased sedimentation due to improper grading practices and stream channelization, resulting in extensive loss of

The unnatural history of Kāne'ohe Bay: coral reef resilience in the face of centuries of anthropogenic impacts.

Science.gov (United States)

Bahr, Keisha D; Jokiel, Paul L; Toonen, Robert J

2015-01-01

Kāne'ohe Bay, which is located on the on the NE coast of O'ahu, Hawai'i, represents one of the most intensively studied estuarine coral reef ecosystems in the world. Despite a long history of anthropogenic disturbance, from early settlement to post European contact, the coral reef ecosystem of Kāne'ohe Bay appears to be in better condition in comparison to other reefs around the world. The island of Moku o Lo'e (Coconut Island) in the southern region of the bay became home to the Hawai'i Institute of Marine Biology in 1947, where researchers have since documented the various aspects of the unique physical, chemical, and biological features of this coral reef ecosystem. The first human contact by voyaging Polynesians occurred at least 700 years ago. By A.D. 1250 Polynesians voyagers had settled inhabitable islands in the region which led to development of an intensive agricultural, fish pond and ocean resource system that supported a large human population. Anthropogenic disturbance initially involved clearing of land for agriculture, intentional or accidental introduction of alien species, modification of streams to supply water for taro culture, and construction of massive shoreline fish pond enclosures and extensive terraces in the valleys that were used for taro culture. The arrival by the first Europeans in 1778 led to further introductions of plants and animals that radically changed the landscape. Subsequent development of a plantation agricultural system led to increased human immigration, population growth and an end to traditional land and water management practices. The reefs were devastated by extensive dredge and fill operations as well as rapid growth of human population, which led to extensive urbanization of the watershed. By the 1960's the bay was severely impacted by increased sewage discharge along with increased sedimentation due to improper grading practices and stream channelization, resulting in extensive loss of coral cover. The reefs of K�

Water addition regulates the metabolic activity of ammonia oxidizers responding to environmental perturbations in dry subhumid ecosystems.

Science.gov (United States)

Hu, Hang-Wei; Macdonald, Catriona A; Trivedi, Pankaj; Holmes, Bronwyn; Bodrossy, Levente; He, Ji-Zheng; Singh, Brajesh K

2015-02-01

Terrestrial arid and semi-arid ecosystems (drylands) constitute about 41% of the Earth's land surface and are predicted to experience increasing fluctuations in water and nitrogen availability. Mounting evidence has confirmed the significant importance of ammonia-oxidizing archaea (AOA) and bacteria (AOB) in nitrification, plant nitrogen availability and atmospheric N2 O emissions, but their responses to environmental perturbations in drylands remain largely unknown. Here we evaluate how the factorial combinations of irrigation and fertilization in forests and land-use change from grassland to forest affects the dynamics of AOA and AOB following a 6-year dryland field study. Potential nitrification rates and AOA and AOB abundances were significantly higher in the irrigated plots, accompanied by considerable changes in community compositions, but their responses to fertilization alone were not significant. DNA-stable isotope probing results showed increased (13) CO2 incorporation into the amoA gene of AOA, but not of AOB, in plots receiving water addition, coupled with significantly higher net mineralization and nitrification rates. High-throughput microarray analysis revealed that active AOA assemblages belonging to Nitrosopumilus and Nitrosotalea were increasingly labelled by (13) CO2 following irrigation. However, no obvious effects of land-use changes on nitrification rates or metabolic activity of AOA and AOB could be observed under dry conditions. We provide evidence that water addition had more important roles than nitrogen fertilization in influencing the autotrophic nitrification in dryland ecosystems, and AOA are increasingly involved in ammonia oxidation when dry soils become wetted. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

Reviews and syntheses: Anthropogenic perturbations to carbon fluxes in Asian river systems - concepts, emerging trends, and research challenges

Science.gov (United States)

Park, Ji-Hyung; Nayna, Omme K.; Begum, Most S.; Chea, Eliyan; Hartmann, Jens; Keil, Richard G.; Kumar, Sanjeev; Lu, Xixi; Ran, Lishan; Richey, Jeffrey E.; Sarma, Vedula V. S. S.; Tareq, Shafi M.; Xuan, Do Thi; Yu, Ruihong

2018-05-01

Human activities are drastically altering water and material flows in river systems across Asia. These anthropogenic perturbations have rarely been linked to the carbon (C) fluxes of Asian rivers that may account for up to 40-50 % of the global fluxes. This review aims to provide a conceptual framework for assessing the human impacts on Asian river C fluxes, along with an update on anthropogenic alterations of riverine C fluxes. Drawing on case studies conducted in three selected rivers (the Ganges, Mekong, and Yellow River) and other major Asian rivers, the review focuses on the impacts of river impoundment and pollution on CO2 outgassing from the rivers draining South, Southeast, and East Asian regions that account for the largest fraction of river discharge and C exports from Asia and Oceania. A critical examination of major conceptual models of riverine processes against observed trends suggests that to better understand altered metabolisms and C fluxes in anthropogenic land-water-scapes, or riverine landscapes modified by human activities, the traditional view of the river continuum should be complemented with concepts addressing spatial and temporal discontinuities created by human activities, such as river impoundment and pollution. Recent booms in dam construction on many large Asian rivers pose a host of environmental problems, including increased retention of sediment and associated C. A small number of studies that measured greenhouse gas (GHG) emissions in dammed Asian rivers have reported contrasting impoundment effects: decreased GHG emissions from eutrophic reservoirs with enhanced primary production vs. increased emissions from the flooded vegetation and soils in the early years following dam construction or from the impounded reaches and downstream estuaries during the monsoon period. These contrasting results suggest that the rates of metabolic processes in the impounded and downstream reaches can vary greatly longitudinally over time as a

Quantifying the pedo-ecohydrological structure and function of degraded, grassland ecosystems

Science.gov (United States)

Brazier, Richard E.

2015-04-01

Grassland ecosystems cover significant areas of the terrestrial land mass, across a range of geoclimates, from arctic tundra, through temperate and semi-arid landscapes. In very few locations, such grasslands may be termed 'pristine' in that they remain undamaged by human activities and resilient to changing climates. In far more cases, grasslands are being degraded, often irreversibly so, with significant implications for a number of ecosystem services related to water resources, soil quality, nutrient cycles, and therefore both global food and water security. This paper draws upon empirical research that has been undertaken over the last decade to characterise a range of different grasslands in terms of soil properties, vegetation structure and geomorphology and to understand how these structures or patterns might interact or control how the grassland ecosystems function. Particular emphasis is placed upon quantifying fluxes of water, within and from grasslands, but also fluxes of sediment, via the processes of soil erosion and finally fluxes of the macronutrients Nitrogen, Phosphorus and Carbon from the landscape to surface waters. Data are presented from semi-arid grasslands, which are subject to severe encroachment by woody species, temperate upland grasslands that have been 'improved' via drainage to support grazing, temperate lowland grasslands, that are unimproved (Culm or Rhôs pastures) and finally intensively managed grasslands in temperate regions, that have been significantly modified via land management practices to improve productivity. It is hypothesised that, once degraded, the structure and function of these very diverse grassland ecosystems follows the same negative trajectory, resulting in depleted soil depths, nutrient storage capacities and therefore reduced plant growth and long-term carbon sequestration. Results demonstrate that similar, but highly complex and non-linear responses to perturbation of the ecosystem are observed, regardless of

Acceleration of modern acidification in the South China Sea driven by anthropogenic CO2

Science.gov (United States)

Liu, Yi; Peng, Zicheng; Zhou, Renjun; Song, Shaohua; Liu, Weiguo; You, Chen-Feng; Lin, Yen-Po; Yu, Kefu; Wu, Chung-Che; Wei, Gangjian; Xie, Luhua; Burr, George S.; Shen, Chuan-Chou

2014-01-01

Modern acidification by the uptake of anthropogenic CO2 can profoundly affect the physiology of marine organisms and the structure of ocean ecosystems. Centennial-scale global and regional influences of anthropogenic CO2 remain largely unknown due to limited instrumental pH records. Here we present coral boron isotope-inferred pH records for two periods from the South China Sea: AD 1048–1079 and AD 1838–2001. There are no significant pH differences between the first period at the Medieval Warm Period and AD 1830–1870. However, we find anomalous and unprecedented acidification during the 20th century, pacing the observed increase in atmospheric CO2. Moreover, pH value also varies in phase with inter-decadal changes in Asian Winter Monsoon intensity. As the level of atmospheric CO2 keeps rising, the coupling global warming via weakening the winter monsoon intensity could exacerbate acidification of the South China Sea and threaten this expansive shallow water marine ecosystem. PMID:24888785

Disturbance, Functional Diversity and Ecosystem Processes: Does Species Identity Matter?

OpenAIRE

Emrick III, Verl Roy

2013-01-01

The role of disturbance is widely recognized as a fundamental driver of ecological organization from individual species to entire landscapes. Anthropogenic disturbances from military training provide a unique opportunity to examine effects of disturbance on vegetation dynamics, physicochemical soil properties, and ecosystem processes. Additionally, plant functional diversity has been suggested as the key to ecosystem processes such as productivity and nutrient dynamics. I investigated how dis...

Sediment bacterial community structures and their predicted functions implied the impacts from natural processes and anthropogenic activities in coastal area.

Science.gov (United States)

Su, Zhiguo; Dai, Tianjiao; Tang, Yushi; Tao, Yile; Huang, Bei; Mu, Qinglin; Wen, Donghui

2018-06-01

Coastal ecosystem structures and functions are changing under natural and anthropogenic influences. In this study, surface sediment samples were collected from disturbed zone (DZ), near estuary zone (NEZ), and far estuary zone (FEZ) of Hangzhou Bay, one of the most seriously polluted bays in China. The bacterial community structures and predicted functions varied significantly in different zones. Firmicutes were found most abundantly in DZ, highlighting the impacts of anthropogenic activities. Sediment total phosphorus was most influential on the bacterial community structures. Predicted by PICRUSt analysis, DZ significantly exceeded FEZ and NEZ in the subcategory of Xenobiotics Biodegradation and Metabolism; and DZ enriched all the nitrate reduction related genes, except nrfA gene. Seawater salinity and inorganic nitrogen, respectively as the representative natural and anthropogenic factor, performed exact-oppositely in nitrogen metabolism functions. The changes of bacterial community compositions and predicted functions provide a new insight into human-induced pollution impacts on coastal ecosystem. Copyright © 2018 Elsevier Ltd. All rights reserved.

Megafauna of vulnerable marine ecosystems in French mediterranean submarine canyons: Spatial distribution and anthropogenic impacts

Science.gov (United States)

Fabri, M.-C.; Pedel, L.; Beuck, L.; Galgani, F.; Hebbeln, D.; Freiwald, A.

2014-06-01

Vulnerable Marine Ecosystems (VME) in the deep Mediterranean Sea have been identified by the General Fisheries Commission for the Mediterranean as consisting of communities of Scleractinia (Lophelia pertusa and Madrepora oculata), Pennatulacea (Funiculina quadrangularis) and Alcyonacea (Isidella elongata). This paper deals with video data recorded in the heads of French Mediterranean canyons. Quantitative observations were extracted from 101 video films recorded during the MEDSEACAN cruise in 2009 (Aamp/Comex). Qualitative information was extracted from four other cruises (two Marum/Comex cruises in 2009 and 2011 and two Ifremer cruises in 1995 and 2010) to support the previous observations in the Cassidaigne and Lacaze-Duthiers canyons. All the species, fishing impacts and litter recognized in the video films recorded from 180 to 700 m depth were mapped using GIS. The abundances and distributions of benthic fishing resources (marketable fishes, Aristeidae, Octopodidae), Vulnerable Marine Species, trawling scars and litter of 17 canyons were calculated and compared, as was the open slope between the Stoechades and Toulon canyons. Funiculina quadrangularis was rarely observed, being confined for the most part to the Marti canyon and, I. elongata was abundant in three canyons (Bourcart, Marti, Petit-Rhône). These two cnidarians were encountered in relatively low abundances, and it may be that they have been swept away by repeated trawling. The Lacaze-Duthiers and Cassidaigne canyons comprised the highest densities and largest colony sizes of scleractinian cold-water corals, whose distribution was mapped in detail. These colonies were often seen to be entangled in fishing lines. The alcyonacean Callogorgia verticillata was observed to be highly abundant in the Bourcart canyon and less abundant in several other canyons. This alcyonacean was also severely affected by bottom fishing gears and is proposed as a Vulnerable Marine Species. Our studies on anthropogenic

Maintaining and restoring sustainable ecosystems in southern Nevada [Chapter 7] (Executive Summary)

Science.gov (United States)

Jeanne C. Chambers; Burton K. Pendleton; Donald W. Sada; Steven M. Ostoja; Matthew L.. Brooks

2013-01-01

Resource managers in southern Nevada are faced with the challenge of determining appropriate goals and objectives and developing viable approaches for maintaining and restoring sustainable ecosystems in the face of rapid socio-ecological and environmental change. Many of southern Nevada’s ecosystems are being subjected to anthropogenic stressors that span global,...

Climate change, cranes, and temperate floodplain ecosystems

Science.gov (United States)

King, Sammy L.

2010-01-01

Floodplain ecosystems provide important habitat to cranes globally. Lateral, longitudinal, vertical, and temporal hydrologic connectivity in rivers is essential to maintaining the functions and values of these systems. Agricultural development, flood control, water diversions, dams, and other anthropogenic activities have greatly affected hydrologic connectivity of river systems worldwide and altered the functional capacity of these systems. Although the specific effects of climate change in any given area are unknown, increased intensity and frequency of flooding and droughts and increased air and water temperatures are among many potential effects that can act synergistically with existing human modifications in these systems to create even greater challenges in maintaining ecosystem productivity. In this paper, I review basic hydrologic and geomorphic processes of river systems and use three North American rivers (Guadalupe, Platte, and Rio Grande) that are important to cranes as case studies to illustrate the challenges facing managers tasked with balancing the needs of cranes and people in the face of an uncertain climatic future. Each river system has unique natural and anthropogenic characteristics that will affect conservation strategies. Mitigating the effects of climate change on river systems necessitates an understanding of river/floodplain/landscape linkages, which include people and their laws as well as existing floodplain ecosystem conditions.

Birth of a closed universe, and the anthropogenic principle

International Nuclear Information System (INIS)

Zel'dovich, Y.

1981-01-01

A scenario is proposed for the evolution of the universe, starting with the quantum birth of a closed world at a minimum in the self-consistent de Sitter cosmological solution with vacuum polarization. The closure of the universe and the permanently supercritical value of its density follow directly from a single condition: that quantum birth take place. The perturbations must be small in order that the de Sitter phase may be sufficiently prolonged to ensure a protracted Friedmann plasma-matter expansion. Thus a universe having the properties we observe may in fact have been singled out by the anthropogenic principle

Anthropogenic impacts on mosquito populations in North America over the past century

Science.gov (United States)

Rochlin, Ilia; Faraji, Ary; Ninivaggi, Dominick V.; Barker, Christopher M.; Kilpatrick, A. Marm

2016-12-01

The recent emergence and spread of vector-borne viruses including Zika, chikungunya and dengue has raised concerns that climate change may cause mosquito vectors of these diseases to expand into more temperate regions. However, the long-term impact of other anthropogenic factors on mosquito abundance and distributions is less studied. Here, we show that anthropogenic chemical use (DDT; dichlorodiphenyltrichloroethane) and increasing urbanization were the strongest drivers of changes in mosquito populations over the last eight decades in areas on both coasts of North America. Mosquito populations have increased as much as tenfold, and mosquito communities have become two- to fourfold richer over the last five decades. These increases are correlated with the decay in residual environmental DDT concentrations and growing human populations, but not with temperature. These results illustrate the far-reaching impacts of multiple anthropogenic disturbances on animal communities and suggest that interactions between land use and chemical use may have unforeseen consequences on ecosystems.

Top-down control as important as nutrient enrichment for eutrophication effects in North Atlantic coastal ecosystems

NARCIS (Netherlands)

Ostman, Orjan; Eklof, Johan; Eriksson, Britas Klemens; Olsson, Jens; Moksnes, Per-Olav; Bergstrom, Ulf

Seagrass and seaweed habitats constitute hotspots for diversity and ecosystem services in coastal ecosystems. These habitats are subject to anthropogenic pressures, of which eutrophication is one major stressor. Eutrophication favours fast-growing ephemeral algae over perennial macroalgae and

The importance of invertebrates when considering the impacts of anthropogenic noise.

Science.gov (United States)

Morley, Erica L; Jones, Gareth; Radford, Andrew N

2014-02-07

Anthropogenic noise is now recognized as a major global pollutant. Rapidly burgeoning research has identified impacts on individual behaviour and physiology through to community disruption. To date, however, there has been an almost exclusive focus on vertebrates. Not only does their central role in food webs and in fulfilling ecosystem services make imperative our understanding of how invertebrates are impacted by all aspects of environmental change, but also many of their inherent characteristics provide opportunities to overcome common issues with the current anthropogenic noise literature. Here, we begin by explaining why invertebrates are likely to be affected by anthropogenic noise, briefly reviewing their capacity for hearing and providing evidence that they are capable of evolutionary adaptation and behavioural plasticity in response to natural noise sources. We then discuss the importance of quantifying accurately and fully both auditory ability and noise content, emphasizing considerations of direct relevance to how invertebrates detect sounds. We showcase how studying invertebrates can help with the behavioural bias in the literature, the difficulties in drawing strong, ecologically valid conclusions and the need for studies on fitness impacts. Finally, we suggest avenues of future research using invertebrates that would advance our understanding of the impact of anthropogenic noise.

Emissions of biogenic VOC from forest ecosystems in central Europe: estimation and comparison with anthropogenic emission inventory.

Science.gov (United States)

Zemankova, Katerina; Brechler, Josef

2010-02-01

This paper describes a method of estimating emission fluxes of biogenic volatile organic compounds (BVOCs) based on the approach proposed by Guenther et al. (1995) and the high-resolution Corine land-cover 2000 database (1x1km resolution). The computed emission fluxes for the Czech Republic (selected for analysis as being representative of a heavily cultivated, central European country) are compared with anthropogenic emissions, both for the entire country and for individual administrative regions. In some regions, BVOC emissions are as high as anthropogenic emissions; however, in most regions the BVOC emissions are approximately 50% of the anthropogenic emissions. The yearly course of BVOC emissions (represented by monoterpenes and isoprene) is presented, along with the spatial distribution of annual mean values. Differences in emission distributions during winter (January) and summer (June) are also considered. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

The impact of anthropogenic and biogenic emissions on surface ozone concentrations in Istanbul.

Science.gov (United States)

Im, Ulas; Poupkou, Anastasia; Incecik, Selahattin; Markakis, Konstantinos; Kindap, Tayfun; Unal, Alper; Melas, Dimitros; Yenigun, Orhan; Topcu, Sema; Odman, M Talat; Tayanc, Mete; Guler, Meltem

2011-03-01

Surface ozone concentrations at Istanbul during a summer episode in June 2008 were simulated using a high resolution and urban scale modeling system coupling MM5 and CMAQ models with a recently developed anthropogenic emission inventory for the region. Two sets of base runs were performed in order to investigate for the first time the impact of biogenic emissions on ozone concentrations in the Greater Istanbul Area (GIA). The first simulation was performed using only the anthropogenic emissions whereas the second simulation was performed using both anthropogenic and biogenic emissions. Biogenic NMVOC emissions were comparable with anthropogenic NMVOC emissions in terms of magnitude. The inclusion of biogenic emissions significantly improved the performance of the model, particularly in reproducing the low night time values as well as the temporal variation of ozone concentrations. Terpene emissions contributed significantly to the destruction of the ozone during nighttime. Biogenic NMVOCs emissions enhanced ozone concentrations in the downwind regions of GIA up to 25ppb. The VOC/NO(x) ratio almost doubled due to the addition of biogenic NMVOCs. Anthropogenic NO(x) and NMVOCs were perturbed by ±30% in another set of simulations to quantify the sensitivity of ozone concentrations to the precursor emissions in the region. The sensitivity runs, as along with the model-calculated ozone-to-reactive nitrogen ratios, pointed NO(x)-sensitive chemistry, particularly in the downwind areas. On the other hand, urban parts of the city responded more to changes in NO(x) due to very high anthropogenic emissions. Copyright © 2010 Elsevier B.V. All rights reserved.

Attribution of irreversible loss to anthropogenic climate change

Science.gov (United States)

Huggel, Christian; Bresch, David; Hansen, Gerrit; James, Rachel; Mechler, Reinhard; Stone, Dáithí; Wallimann-Helmer, Ivo

2016-04-01

of land area due to coastal and hillslope erosion and sea level change; loss of plant and animal species, loss of ecosystems and biodiversity; loss of human lives, homelands, and cultural identity. Attribution to anthropogenic climate change is analyzed based on recent progress following from the IPCC AR5. Generally, high confidence in attributing irreversible loss to anthropogenic climate change is found in physical systems and more specifically in cryosphere environments, both in mountain and polar regions. Detected loss in terrestrial ecosystems has typically low confidence in attribution whereas loss in some ocean ecosystems (corals) has high confidence. Impacts in human systems that may be classified as irreversible loss are of low confidence in terms of attribution except for the Arctic where higher confidence for a relation with anthropogenic emissions was found. Our analysis suggests that scientific progress in detection and attribution is now at a level that would likely allow policy, or courts, to define mechanisms, or take decisions, as related to irreversible loss in many cryosphere systems. On the other hand, policy may need to consider that at least in the near future it will be difficult to establish clear tracks between irreversible loss in most human systems and anthropogenic climate change, a domain, which however is at the forefront of discussions. We end our discussion with setting out ideas for further clarification of different categories of irreversible loss, including in human systems, and the role of attribution in any policy or legal mechanism in order to help in the development of just and sensible solutions.

Cities as Novel Biomes;Recognizing Urban Ecosystem Services as Anthropogenic

Directory of Open Access Journals (Sweden)

Stephanie ePincetl

2015-12-01

Full Text Available Urban Ecosystem Science is now an established science, arising along side the historic shift of humans to becoming in majority urban dwellers. In this Perspective I suggest there is a need to develop a new framework for UES as embedded in distinct urban biomes that can be classified by city-type and typologized. UES are largely the artifact of human decision making from what to plant where, to determining the urban infrastructure type in which UES will be placed. Developing urban typologies by climate zone, level of development, size and history will better enable the understanding of UES. I attempt to show the rise of the importance of nature, and of urban nature following the development of industrial city, and the importance of human intent in creating these urban ecosystems over time. If humans choose to manage cities through increasing UES, this will require coupled shifts, the shift in rules and regulations, goals and processes and shifts in urban form, infrastructure and function – socio-technical-ecological changes – driven by human decision-making. Such efforts will vary widely by city -- by urban biome.

Reviews and syntheses: Anthropogenic perturbations to carbon fluxes in Asian river systems – concepts, emerging trends, and research challenges

Directory of Open Access Journals (Sweden)

J.-H. Park

2018-05-01

Full Text Available Human activities are drastically altering water and material flows in river systems across Asia. These anthropogenic perturbations have rarely been linked to the carbon (C fluxes of Asian rivers that may account for up to 40–50 % of the global fluxes. This review aims to provide a conceptual framework for assessing the human impacts on Asian river C fluxes, along with an update on anthropogenic alterations of riverine C fluxes. Drawing on case studies conducted in three selected rivers (the Ganges, Mekong, and Yellow River and other major Asian rivers, the review focuses on the impacts of river impoundment and pollution on CO2 outgassing from the rivers draining South, Southeast, and East Asian regions that account for the largest fraction of river discharge and C exports from Asia and Oceania. A critical examination of major conceptual models of riverine processes against observed trends suggests that to better understand altered metabolisms and C fluxes in anthropogenic land-water-scapes, or riverine landscapes modified by human activities, the traditional view of the river continuum should be complemented with concepts addressing spatial and temporal discontinuities created by human activities, such as river impoundment and pollution. Recent booms in dam construction on many large Asian rivers pose a host of environmental problems, including increased retention of sediment and associated C. A small number of studies that measured greenhouse gas (GHG emissions in dammed Asian rivers have reported contrasting impoundment effects: decreased GHG emissions from eutrophic reservoirs with enhanced primary production vs. increased emissions from the flooded vegetation and soils in the early years following dam construction or from the impounded reaches and downstream estuaries during the monsoon period. These contrasting results suggest that the rates of metabolic processes in the impounded and downstream reaches can vary greatly longitudinally

Environmental and Anthropogenic Factors Influencing Salamanders in Riparian Forests: A Review

Directory of Open Access Journals (Sweden)

Hannah L. Clipp

2014-11-01

Full Text Available Salamanders and riparian forests are intimately interconnected. Salamanders are integral to ecosystem functions, contributing to vertebrate biomass and complex food webs in riparian forests. In turn, these forests are critical ecosystems that perform many environmental services, facilitate high biodiversity and species richness, and provide habitat to salamander populations. Due to the global decline of amphibians, it is important to understand, as thoroughly and holistically as possible, the roles of environmental parameters and the impact of human activities on salamander abundance and diversity in riparian forests. To determine the population responses of salamanders to a variety of environmental factors and anthropogenic activities, we conducted a review of published literature that compared salamander abundance and diversity, and then summarized and synthesized the data into general patterns. We identify stream quality, leaf litter and woody debris, riparian buffer width, and soil characteristics as major environmental factors influencing salamander populations in riparian forests, describe and explain salamander responses to those factors, and discuss the effects of anthropogenic activities such as timber harvest, prescribed fires, urbanization, road construction, and habitat fragmentation. This review can assist land and natural resource managers in anticipating the consequences of human activities and preparing strategic conservation plans.

Particularities of pathogenic microorganism development at anthropogenic influence and estimate of their adaptation potential by means of radiobiological method

International Nuclear Information System (INIS)

Shilina, Yu.V.; Gushcha, N.I.; Dyachenko, A.I.; Dmitriev, A.P.; Molozhava, O.S.; Romashko, V.M.

2008-01-01

Influence of anthropogenic factors on ecosystems causes their structure disturbance and reduction of species variety. Some resistance nonspecific forms of pathogenic microorganisms, which have high adaptation potential, become dominant. Thus their aggressiveness can increase. (authors)

Structure, functioning, and cumulative stressors of Mediterranean deep-sea ecosystems

Science.gov (United States)

Tecchio, Samuele; Coll, Marta; Sardà, Francisco

2015-06-01

Environmental stressors, such as climate fluctuations, and anthropogenic stressors, such as fishing, are of major concern for the management of deep-sea ecosystems. Deep-water habitats are limited by primary productivity and are mainly dependent on the vertical input of organic matter from the surface. Global change over the latest decades is imparting variations in primary productivity levels across oceans, and thus it has an impact on the amount of organic matter landing on the deep seafloor. In addition, anthropogenic impacts are now reaching the deep ocean. The Mediterranean Sea, the largest enclosed basin on the planet, is not an exception. However, ecosystem-level studies of response to varying food input and anthropogenic stressors on deep-sea ecosystems are still scant. We present here a comparative ecological network analysis of three food webs of the deep Mediterranean Sea, with contrasting trophic structure. After modelling the flows of these food webs with the Ecopath with Ecosim approach, we compared indicators of network structure and functioning. We then developed temporal dynamic simulations varying the organic matter input to evaluate its potential effect. Results show that, following the west-to-east gradient in the Mediterranean Sea of marine snow input, organic matter recycling increases, net production decreases to negative values and trophic organisation is overall reduced. The levels of food-web activity followed the gradient of organic matter availability at the seafloor, confirming that deep-water ecosystems directly depend on marine snow and are therefore influenced by variations of energy input, such as climate-driven changes. In addition, simulations of varying marine snow arrival at the seafloor, combined with the hypothesis of a possible fishery expansion on the lower continental slope in the western basin, evidence that the trawling fishery may pose an impact which could be an order of magnitude stronger than a climate

Human activities cause distinct dissolved organic matter composition across freshwater ecosystems

Science.gov (United States)

Williams, Clayton J.; Frost, Paul C.; Morales-Williams, Ana M.; Larson, James H.; Richardson, William B.; Chiandet, Aisha S.; Xenopoulos, Marguerite A.

2016-01-01

Dissolved organic matter (DOM) composition in freshwater ecosystems is influenced by interactions between physical, chemical, and biological processes that are controlled, at one level, by watershed landscape, hydrology, and their connections. Against this environmental template, humans may strongly influence DOM composition. Yet, we lack a comprehensive understanding of DOM composition variation across freshwater ecosystems differentially affected by human activity. Using optical properties, we described DOM variation across five ecosystem groups of the Laurentian Great Lakes Region: large lakes, Kawartha Lakes, Experimental Lakes Area, urban stormwater ponds, and rivers (n = 184 sites). We determined how between ecosystem variation in DOM composition related to watershed size, land use and cover, water quality measures (conductivity, dissolved organic carbon (DOC), nutrient concentration, chlorophyll a), and human population density. The five freshwater ecosystem groups had distinctive DOM composition from each other. These significant differences were not explained completely through differences in watershed size nor spatial autocorrelation. Instead, multivariate partial least squares regression showed that DOM composition was related to differences in human impact across freshwater ecosystems. In particular, urban/developed watersheds with higher human population densities had a unique DOM composition with a clear anthropogenic influence that was distinct from DOM composition in natural land cover and/or agricultural watersheds. This nonagricultural, human developed impact on aquatic DOM was most evident through increased levels of a microbial, humic-like parallel factor analysis component (C6). Lotic and lentic ecosystems with low human population densities had DOM compositions more typical of clear water to humic-rich freshwater ecosystems but C6 was only present at trace to background levels. Consequently, humans are strongly altering the quality of DOM in

Damped trophic cascades driven by fishing in model marine ecosystems

DEFF Research Database (Denmark)

Andersen, Ken Haste; Pedersen, Martin

2010-01-01

The largest perturbation on upper trophic levels of many marine ecosystems stems from fishing. The reaction of the ecosystem goes beyond the trophic levels directly targeted by the fishery. This reaction has been described either as a change in slope of the overall size spectrum or as a trophic...... cascade triggered by the removal of top predators. Here we use a novel size- and trait-based model to explore how marine ecosystems might react to perturbations from different types of fishing pressure. The model explicitly resolves the whole life history of fish, from larvae to adults. The results show...... that fishing does not change the overall slope of the size spectrum, but depletes the largest individuals and induces trophic cascades. A trophic cascade can propagate both up and down in trophic levels driven by a combination of changes in predation mortality and food limitation. The cascade is damped...

A Framework to Quantify the Strength of the Ecological Links Between an Environmental Stressor and Final Ecosystem Services

Science.gov (United States)

Anthropogenic stressors such as climate change, fire, and pollution are driving shifts in ecosystem function and resilience. Scientists generally rely on biological indicators of these stressors to signal that ecosystem conditions have been altered beyond an acceptable amount. Ho...

Coupling ecosystems exposure to nitrogen and species sensitivity to hypoxia: modelling marine eutrophication in LCIA

DEFF Research Database (Denmark)

Cosme, Nuno Miguel Dias; Koski, Marja; Hauschild, Michael Zwicky

Characterisation modelling in Life Cycle Impact Assessment (LCIA) quantifies impacts of anthropogenic emissions by applying substance-specific impact potentials, or Characterisation Factors (CF), to the amount of substances emitted. Nitrogen (N) emissions from human activities enrich coastal marine...... ecosystems and promote planktonic growth that may lead to marine eutrophication impacts. Excessive algal biomass and dissolved oxygen (DO) depletion typify the ecosystem response to the nutrient input. The present novel method couples a mechanistic model of coastal biological processes that determines...... the ecosystem response (exposure) to anthropogenic N enrichment (eXposure Factor, XF [kgO2·kgN-1]) with the sensitivity of species exposed to oxygen-depleted waters (Effect Factor, EF [(PAF)·m3·kgO2-1], expressed as a Potentially Affected Fraction (PAF) of species). Thus, the coupled indicator (XF*EF, [(PAF)·m3...

Anthropogenic Effects on Forest Ecosystems at Various Spatio-Temporal Scales

Directory of Open Access Journals (Sweden)

Michael Bredemeier

2002-01-01

Full Text Available The focus in this review of long-term effects on forest ecosystems is on human impact. As a classification of this differentiated and complex matter, three domains of long-term effects with different scales in space and time are distinguished: 1- Exploitation and conversion history of forests in areas of extended human settlement 2- Long-range air pollution and acid deposition in industrialized regions 3- Current global loss of forests and soil degradation.

Management Strategy Evaluation Applied to Coral Reef Ecosystems in Support of Ecosystem-Based Management.

Directory of Open Access Journals (Sweden)

Mariska Weijerman

Full Text Available Ecosystem modelling is increasingly used to explore ecosystem-level effects of changing environmental conditions and management actions. For coral reefs there has been increasing interest in recent decades in the use of ecosystem models for evaluating the effects of fishing and the efficacy of marine protected areas. However, ecosystem models that integrate physical forcings, biogeochemical and ecological dynamics, and human induced perturbations are still underdeveloped. We applied an ecosystem model (Atlantis to the coral reef ecosystem of Guam using a suite of management scenarios prioritized in consultation with local resource managers to review the effects of each scenario on performance measures related to the ecosystem, the reef-fish fishery (e.g., fish landings and coral habitat. Comparing tradeoffs across the selected scenarios showed that each scenario performed best for at least one of the selected performance indicators. The integrated 'full regulation' scenario outperformed other scenarios with four out of the six performance metrics at the cost of reef-fish landings. This model application quantifies the socio-ecological costs and benefits of alternative management scenarios. When the effects of climate change were taken into account, several scenarios performed equally well, but none prevented a collapse in coral biomass over the next few decades assuming a business-as-usual greenhouse gas emissions scenario.

Management Strategy Evaluation Applied to Coral Reef Ecosystems in Support of Ecosystem-Based Management.

Science.gov (United States)

Weijerman, Mariska; Fulton, Elizabeth A; Brainard, Russell E

2016-01-01

Ecosystem modelling is increasingly used to explore ecosystem-level effects of changing environmental conditions and management actions. For coral reefs there has been increasing interest in recent decades in the use of ecosystem models for evaluating the effects of fishing and the efficacy of marine protected areas. However, ecosystem models that integrate physical forcings, biogeochemical and ecological dynamics, and human induced perturbations are still underdeveloped. We applied an ecosystem model (Atlantis) to the coral reef ecosystem of Guam using a suite of management scenarios prioritized in consultation with local resource managers to review the effects of each scenario on performance measures related to the ecosystem, the reef-fish fishery (e.g., fish landings) and coral habitat. Comparing tradeoffs across the selected scenarios showed that each scenario performed best for at least one of the selected performance indicators. The integrated 'full regulation' scenario outperformed other scenarios with four out of the six performance metrics at the cost of reef-fish landings. This model application quantifies the socio-ecological costs and benefits of alternative management scenarios. When the effects of climate change were taken into account, several scenarios performed equally well, but none prevented a collapse in coral biomass over the next few decades assuming a business-as-usual greenhouse gas emissions scenario.

From theoretical to actual ecosystem services: mapping beneficiaries and spatial flows in ecosystem service assessments

Directory of Open Access Journals (Sweden)

Kenneth J. Bagstad

2014-06-01

Full Text Available Ecosystem services mapping and modeling has focused more on supply than demand, until recently. Whereas the potential provision of economic benefits from ecosystems to people is often quantified through ecological production functions, the use of and demand for ecosystem services has received less attention, as have the spatial flows of services from ecosystems to people. However, new modeling approaches that map and quantify service-specific sources (ecosystem capacity to provide a service, sinks (biophysical or anthropogenic features that deplete or alter service flows, users (user locations and level of demand, and spatial flows can provide a more complete understanding of ecosystem services. Through a case study in Puget Sound, Washington State, USA, we quantify and differentiate between the theoretical or in situ provision of services, i.e., ecosystems' capacity to supply services, and their actual provision when accounting for the location of beneficiaries and the spatial connections that mediate service flows between people and ecosystems. Our analysis includes five ecosystem services: carbon sequestration and storage, riverine flood regulation, sediment regulation for reservoirs, open space proximity, and scenic viewsheds. Each ecosystem service is characterized by different beneficiary groups and means of service flow. Using the ARtificial Intelligence for Ecosystem Services (ARIES methodology we map service supply, demand, and flow, extending on simpler approaches used by past studies to map service provision and use. With the exception of the carbon sequestration service, regions that actually provided services to people, i.e., connected to beneficiaries via flow paths, amounted to 16-66% of those theoretically capable of supplying services, i.e., all ecosystems across the landscape. These results offer a more complete understanding of the spatial dynamics of ecosystem services and their effects, and may provide a sounder basis for

Anomalous, extreme weather disrupts obligate seed dispersal mutualism: snow in a subtropical forest ecosystem.

Science.gov (United States)

Zhou, Youbing; Newman, Chris; Chen, Jin; Xie, Zongqiang; Macdonald, David W

2013-09-01

Ongoing global climate change is predicted to increase the frequency and magnitude of extreme weather events, impacting population dynamics and community structure. There is, however, a critical lack of case studies considering how climatic perturbations affect biotic interactions. Here, we document how an obligate seed dispersal mutualism was disrupted by a temporally anomalous and meteorologically extreme interlude of unseasonably frigid weather, with accompanying snowstorms, in subtropical China, during January-February 2008. Based on the analysis of 5892 fecal samples (representing six mammalian seed dispersers), this event caused a substantial disruption to the relative seed dispersal function for the raisin tree Hovenia dulcis from prestorm 6.29 (2006) and 11.47 (2007), down to 0.35 during the storm (2008). Crucially, this was due to impacts on mammalian seed dispersers and not due to a paucity of fruit, where 4.63 fruit per branch were available in January 2008, vs. 3.73 in 2006 and 3.58 in 2007. An induced dietary shift occurred among omnivorous carnivores during this event, from the consumption fruit to small mammals and birds, reducing their role in seed dispersal substantially. Induced range shift extinguished the functionality of herbivorous mammals completely, however, seed dispersal function was compensated in part by three omnivorous carnivores during poststorm years, and thus while the mutualism remained intact it was enacted by a narrower assemblage of species, rendering the system more vulnerable to extrinsic perturbations. The storm's extended effects also had anthropogenic corollaries - migrating ungulates becoming exposed to heightened levels of illegal hunting - causing long-term modification to the seed dispersal community and mutualism dynamics. Furthermore, degraded forests proved especially vulnerable to the storm's effects. Considering increasing climate variability and anthropogenic disturbance, the impacts of such massive, aberrant

Tipping elements in the Arctic marine ecosystem.

Science.gov (United States)

Duarte, Carlos M; Agustí, Susana; Wassmann, Paul; Arrieta, Jesús M; Alcaraz, Miquel; Coello, Alexandra; Marbà, Núria; Hendriks, Iris E; Holding, Johnna; García-Zarandona, Iñigo; Kritzberg, Emma; Vaqué, Dolors

2012-02-01

The Arctic marine ecosystem contains multiple elements that present alternative states. The most obvious of which is an Arctic Ocean largely covered by an ice sheet in summer versus one largely devoid of such cover. Ecosystems under pressure typically shift between such alternative states in an abrupt, rather than smooth manner, with the level of forcing required for shifting this status termed threshold or tipping point. Loss of Arctic ice due to anthropogenic climate change is accelerating, with the extent of Arctic sea ice displaying increased variance at present, a leading indicator of the proximity of a possible tipping point. Reduced ice extent is expected, in turn, to trigger a number of additional tipping elements, physical, chemical, and biological, in motion, with potentially large impacts on the Arctic marine ecosystem.

Variations of Ecosystem Service Value in Response to Land-Use Change in the Kashgar Region, Northwest China

OpenAIRE

Aynur Mamat; Ümüt Halik; Aihemaitijiang Rouzi

2018-01-01

Increasing anthropogenic activities have significantly altered ecosystems in arid oasis regions. Estimating the impact on a wide range of ecosystem services is important for decision making and the sustainable development of these regions. This study analyzed time-series Landsat data to determine the influences of oasis land-use changes on the ecosystem services in the Kashgar region in Northwest China. The following results were found. The total value of the ecosystem services in the Kashgar...

Changes in food web structure and ecosystem functioning of a large, shallow Chinese lake during the 1950s, 1980s and 2000s

NARCIS (Netherlands)

Kong, Xiangzhen; He, Wei; Liu, Wenxiu; Yang, Bin; Xu, Fuliu; Jørgensen, Sven Erik; Mooij, W.M.

2016-01-01

Food web structure dynamics and ecosystem functioning are strongly linked, and both are indispensable in evaluating ecosystem development in lakes under multiple anthropogenic stressors. However, model-based approaches concerning the changes in food web structure and ecosystem functioning in a

Trace gases and other potential perturbations to global climate

International Nuclear Information System (INIS)

Wang, W.; Wuebbles, D.J.; Washington, W.M.; Isaacs, R.G.; Molnar, G.

1986-01-01

We review the various natural and anthropogenic factors that may affect the climate. The purpose is to summarize our understanding of these factors and their potential future climatic effects so that CO 2 -induced climate change can be viewed in a proper context. The factors we discuss include trace gases, anthropogenic and volcanic aerosols, variation of solar constant, change of surface characteristics, and releases of waste heat. We discuss the origins of the various natural and anthropogenic perturbations, the physical and chemical processes and their interactions, model sensitivity calculations, and model projections of their potential future climatic effects. The discussions center on trace gases because of their potentially large climatic effects. It appears that the increases of atmospheric trace gases of other kinds in addition to CO 2 could have important climatic effects. The model calculations suggest that the combined effect of these other trace gases, and the associated change of atmospheric ozone and water vapor distributions, could potentially warm the climate by an amount comparable in magnitude to the effect of doubling the CO 2 . Aerosols of anthropogenic origins may have substantial effects on regional climate, while the volcanic aerosols may have an effect on large-scale climate for up to a few years after injection. Changes of surface characteristics and releases of waste heat may also have substantial effects on the regional climate, but these effects are most likely to be small when compared with the effect of CO 2 increase. Changes of solar constant could have an effect on the global scale, but the time scale is much longer. There is much more that needs to be learned with regard to the above mentioned natural and anthropogenic factors that may affect the climate. A brief summary of those needs is presented

People, pollution and pathogens - Global change impacts in mountain freshwater ecosystems.

Science.gov (United States)

Schmeller, Dirk S; Loyau, Adeline; Bao, Kunshan; Brack, Werner; Chatzinotas, Antonis; De Vleeschouwer, Francois; Friesen, Jan; Gandois, Laure; Hansson, Sophia V; Haver, Marilen; Le Roux, Gaël; Shen, Ji; Teisserenc, Roman; Vredenburg, Vance T

2018-05-01

Mountain catchments provide for the livelihood of more than half of humankind, and have become a key destination for tourist and recreation activities globally. Mountain ecosystems are generally considered to be less complex and less species diverse due to the harsh environmental conditions. As such, they are also more sensitive to the various impacts of the Anthropocene. For this reason, mountain regions may serve as sentinels of change and provide ideal ecosystems for studying climate and global change impacts on biodiversity. We here review different facets of anthropogenic impacts on mountain freshwater ecosystems. We put particular focus on micropollutants and their distribution and redistribution due to hydrological extremes, their direct influence on water quality and their indirect influence on ecosystem health via changes of freshwater species and their interactions. We show that those changes may drive pathogen establishment in new environments with harmful consequences for freshwater species, but also for the human population. Based on the reviewed literature, we recommend reconstructing the recent past of anthropogenic impact through sediment analyses, to focus efforts on small, but highly productive waterbodies, and to collect data on the occurrence and variability of microorganisms, biofilms, plankton species and key species, such as amphibians due to their bioindicator value for ecosystem health and water quality. The newly gained knowledge can then be used to develop a comprehensive framework of indicators to robustly inform policy and decision making on current and future risks for ecosystem health and human well-being. Copyright © 2017 Elsevier B.V. All rights reserved.

From theoretical to actual ecosystem services: mapping beneficiaries and spatial flows in ecosystem service assessments

Science.gov (United States)

Bagstad, Kenneth J.; Villa, Ferdinando; Batker, David; Harrison-Cox, Jennifer; Voigt, Brian; Johnson, Gary W.

2014-01-01

Ecosystem services mapping and modeling has focused more on supply than demand, until recently. Whereas the potential provision of economic benefits from ecosystems to people is often quantified through ecological production functions, the use of and demand for ecosystem services has received less attention, as have the spatial flows of services from ecosystems to people. However, new modeling approaches that map and quantify service-specific sources (ecosystem capacity to provide a service), sinks (biophysical or anthropogenic features that deplete or alter service flows), users (user locations and level of demand), and spatial flows can provide a more complete understanding of ecosystem services. Through a case study in Puget Sound, Washington State, USA, we quantify and differentiate between the theoretical or in situ provision of services, i.e., ecosystems’ capacity to supply services, and their actual provision when accounting for the location of beneficiaries and the spatial connections that mediate service flows between people and ecosystems. Our analysis includes five ecosystem services: carbon sequestration and storage, riverine flood regulation, sediment regulation for reservoirs, open space proximity, and scenic viewsheds. Each ecosystem service is characterized by different beneficiary groups and means of service flow. Using the ARtificial Intelligence for Ecosystem Services (ARIES) methodology we map service supply, demand, and flow, extending on simpler approaches used by past studies to map service provision and use. With the exception of the carbon sequestration service, regions that actually provided services to people, i.e., connected to beneficiaries via flow paths, amounted to 16-66% of those theoretically capable of supplying services, i.e., all ecosystems across the landscape. These results offer a more complete understanding of the spatial dynamics of ecosystem services and their effects, and may provide a sounder basis for economic

Bacterial diversity in relatively pristine and anthropogenically-influenced mangrove ecosystems (Goa, India)

Digital Repository Service at National Institute of Oceanography (India)

Fernandes, S.O.; Kirchman, D.L.; Michotey, V.D.; Bonin, P.C.; LokaBharathi, P.A.

at both locations comprising 43-46% of total tags. The Tuvem ecosystem was characterized by an abundance of members belonging to the class Deltaproteobacteria (21%), ~ 2100 phylotypes and 1561 operational taxonomic units (OTUs) sharing > 97% similarity...

Spring flood pH decline in northern Sweden: Towards an operational model separating natural acidity from anthropogenic acidification

Energy Technology Data Exchange (ETDEWEB)

Laudon, H.

1999-10-01

The spring flood is a defining feature of the ecosystem in northern Sweden. In this region, spring flood is an occasion for dramatic hydrochemical changes that profoundly effect the biodiversity of the aquatic ecosystem. Spring flood is also the period most susceptible to anthropogenic acidification. A belief in the anthropogenic component to pH decline during spring flood has been an important factor in spending over half a billion crowns to lime surface waters in Northern Sweden during the last decade. The natural component of episodic pH decline during spring flood, however, has received less attention. The main objective of this work is to present an operational model for separating and quantifying the anthropogenic and natural contributions of episodic acidification during high flow events in Northern Sweden. The key assumptions in this model are that baseflow ANC has not been affected by anthropogenic acidification, that DOC has not changed due to modern land-use practice and that natural dilution during hydrological episodes can be quantified. The limited data requirements of 10-15 stream water samples before and during spring flood make the model suitable for widespread use in environmental monitoring programs. This makes it possible to distinguish trends of human impact as well as natural pH decline in space and time. Modeling results from northern Sweden demonstrate that the natural driving mechanisms of dilution and organic acidity were the dominant factors in the episodic acidification of spring flood in the region. The anthropogenic contribution to spring pH decline was similar in size to the natural contribution in only two of the more than 30 events where this model was applied. Natural factors alone were found to cause pH values below 4.5 in some streams. Anthropogenic sources of acidity can be superimposed on this natural dynamics. In the sites studied, the magnitude of the anthropogenic ANC decline was correlated to the winter deposition of

Assessment of the influence of anthropogenic factors on elements of the ecological network in Vojvodina (Serbia using the Leopold matrix

Directory of Open Access Journals (Sweden)

Kicošev Vesna

2015-01-01

Full Text Available Salt steppes and marshes represent the most valuable ecosystems in the world, providing numerous ecosystem services that are extremely vulnerable to anthropogenic influences. These types of habitat in the territory of Serbia are most dominant in Banat and a significant portion of them is under protection or in the process of becoming protected. The section surrounding the protected areas of Slano Kopovo Special Nature Reserve, Rusanda Nature Park and Okanj Bara Special Nature Reserve with the non-building area of Novi Bečej, Kumane, Melenci, Elemir and Taraš cadastral municipalities, has been chosen for the analysis. The aim of this paper was to assess the influence of specific anthropogenic factors on the elements of an ecological network using the analytical method that can generate the required results in a manner suitable for presentation to various stakeholders. To achieve this aim, the Leopold matrix model, used for assessing anthropogenic influence on the environment, has been chosen. The specificity of this issue of protecting and preserving elements of an ecological network resulted in the need to isolate and evaluate the factors affecting the preservation of habitats and functionality of ecosystems, unlike the concept of Leopold matrix, which treats all factors as equally important in the process of evaluation. Evaluation results indicate significant effects of historical, perennial manner of using the area and other resources in the non-building area.

Quantification of anthropogenic impact on groundwater-dependent terrestrial ecosystem using geochemical and isotope tools combined with 3-D flow and transport modelling

Science.gov (United States)

Zurek, A. J.; Witczak, S.; Dulinski, M.; Wachniew, P.; Rozanski, K.; Kania, J.; Postawa, A.; Karczewski, J.; Moscicki, W. J.

2015-02-01

Groundwater-dependent ecosystems (GDEs) have important functions in all climatic zones as they contribute to biological and landscape diversity and provide important economic and social services. Steadily growing anthropogenic pressure on groundwater resources creates a conflict situation between nature and man which are competing for clean and safe sources of water. Such conflicts are particularly noticeable in GDEs located in densely populated regions. A dedicated study was launched in 2010 with the main aim to better understand the functioning of a groundwater-dependent terrestrial ecosystem (GDTE) located in southern Poland. The GDTE consists of a valuable forest stand (Niepolomice Forest) and associated wetland (Wielkie Błoto fen). It relies mostly on groundwater from the shallow Quaternary aquifer and possibly from the deeper Neogene (Bogucice Sands) aquifer. In July 2009 a cluster of new pumping wells abstracting water from the Neogene aquifer was set up 1 km to the northern border of the fen. A conceptual model of the Wielkie Błoto fen area for the natural, pre-exploitation state and for the envisaged future status resulting from intense abstraction of groundwater through the new well field was developed. The main aim of the reported study was to probe the validity of the conceptual model and to quantify the expected anthropogenic impact on the studied GDTE. A wide range of research tools was used. The results obtained through combined geologic, geophysical, geochemical, hydrometric and isotope investigations provide strong evidence for the existence of upward seepage of groundwater from the deeper Neogene aquifer to the shallow Quaternary aquifer supporting the studied GDTE. Simulations of the groundwater flow field in the study area with the aid of a 3-D flow and transport model developed for Bogucice Sands (Neogene) aquifer and calibrated using environmental tracer data and observations of hydraulic head in three different locations on the study area

Symbiotic bacteria of helminths: what role may they play in ecosystems under anthropogenic stress?

Science.gov (United States)

Morley, N J

2016-11-01

Symbiotic bacteria are a common feature of many animals, particularly invertebrates, from both aquatic and terrestrial habitats. These bacteria have increasingly been recognized as performing an important role in maintaining invertebrate health. Both ecto- and endoparasitic helminths have also been found to harbour a range of bacterial species which provide a similar function. The part symbiotic bacteria play in sustaining homeostasis of free-living invertebrates exposed to anthropogenic pressure (climate change, pollution), and the consequences to invertebrate populations when their symbionts succumb to poor environmental conditions, are increasingly important areas of research. Helminths are also susceptible to environmental stress and their symbiotic bacteria may be a key aspect of their responses to deteriorating conditions. This article summarizes the ecophysiological relationship helminths have with symbiotic bacteria and the role they play in maintaining a healthy parasite and the relevance of specific changes that occur in free-living invertebrate-bacteria interactions under anthropogenic pressure to helminths and their bacterial communities. It also discusses the importance of understanding the mechanistic sensitivity of helminth-bacteria relationships to environmental stress for comprehending the responses of parasites to challenging conditions.

Perturbation vectors to evaluate air quality using lichens and bromeliads: a Brazilian case study.

Science.gov (United States)

Monna, F; Marques, A N; Guillon, R; Losno, R; Couette, S; Navarro, N; Dongarra, G; Tamburo, E; Varrica, D; Chateau, C; Nepomuceno, F O

2017-10-17

Samples of one lichen species, Parmotrema crinitum, and one bromeliad species, Tillandsia usneoides, were collected in the state of Rio de Janeiro, Brazil, at four sites differently affected by anthropogenic pollution. The concentrations of aluminum, cadmium, copper, iron, lanthanum, lead, sulfur, titanium, zinc, and zirconium were determined by inductively coupled plasma-atomic emission spectroscopy. The environmental diagnosis was established by examining compositional changes via perturbation vectors, an underused family of methods designed to circumvent the problem of closure in any compositional dataset. The perturbation vectors between the reference site and the other three sites were similar for both species, although body concentration levels were different. At each site, perturbation vectors between lichens and bromeliads were approximately the same, whatever the local pollution level. It should thus be possible to combine these organisms, though physiologically different, for air quality surveys, after making all results comparable with appropriate correction. The use of perturbation vectors seems particularly suitable for assessing pollution level by biomonitoring, and for many frequently met situations in environmental geochemistry, where elemental ratios are more relevant than absolute concentrations.

Predicting community and ecosystem outcomes of mycorrhizal responses to global change.

NARCIS (Netherlands)

Johnson, N.C.; Angelard, C.; Sanders, I.R.; Kiers, E.T.

2013-01-01

Mycorrhizal symbioses link the biosphere with the lithosphere by mediating nutrient cycles and energy flow though terrestrial ecosystems. A more mechanistic understanding of these plant-fungal associations may help ameliorate anthropogenic changes to C and N cycles and biotic communities. We explore

An impact of deforestation by extreme weather events on Sphagnum peatland ecosystem

Science.gov (United States)

Slowinski, M. M.; Łuców, D.; Kołaczek, P.; Tjallingii, R.; Lane, C. S.; Slowinska, S.; Tyszkowski, S.; Łokas, E.; Theuerkauf, M.; Brauer, A.; Lamentowicz, M.

2017-12-01

An increase in extreme weather phenomena has been observed over the last decades as a result of global climate warming. Terrestrial ecosystems are influenced by different types of disturbances such as e.g. deforestation, land-use, fragmentation, fire, floods or storms. Disturbance triggers may be natural or anthropogenic, but usually we observe negative feedback loops and interconnected causal factors. Here we investigate the effects of a tornado event on the peatland ecosystem of the Tuchola Pinewoods, Northern Poland. Deforestation by tornado events can cause severe perturbations of the hydrology and erosion that, in turn, affects adjacent lakes and peatlands. Martwe peatland provide an exceptional opportunity to study the impact of such extreme events, as it was struck by a tornado in 2012. Our research is focused on lake-peatland ecosystems that were directly affected by this tornado, and we consider the general transformation of the vegetation (mainly forests) over the last 150 years. Extensive clearing of the forest occurred in the nineteenth century due to human activity, and we compare this with the impact of the 2012 tornado. Accurate reconstructions will rely on a broad range of palaeoecological techniques such as pollen, macro-remains and testate amoebae, but also on geochemistry, i.e. μXRF scanning. The chronology of the records is based on 210Pb and radiocarbon dating and will incorporate correlations using (crypto)tephra markers of the Eyjafjöll (2010) and Askja (1875) eruptions. We expect to observe that disturbance (tornado-induced deforestation) affects the short-term changes in peatland productivity and biodiversity, through a cascading "top-down" effect. This research addresses the emerging issue of the impact of extreme phenomena and more general climate changes on peatland ecosystems, which will potentially help to inform adaptations to the environmental consequences of extreme events in the future. This project is funded by the Polish

Whole-ecosystem experimental manipulations of tropical forests

OpenAIRE

Fayle, Tom M; Turner, Edgar Clive; Basset, Yves; Ewers, Robert M; Reynolds, Glen; Novotny, Vojtech

2015-01-01

Tropical forests are highly diverse systems involving extraordinary numbers of interactions between species, with each species responding in a different way to the abiotic environment. Understanding how these systems function and predicting how they respond to anthropogenic global change is extremely challenging. We argue for the necessity of ‘whole-ecosystem’ experimental manipulations, in which the entire ecosystem is targeted, either to reveal the functioning of the...

An Earth system view on boundaries for human perturbation of the N and P cycles

Science.gov (United States)

Cornell, Sarah; de Vries, Wim

2015-04-01

The appropriation and transformation of land, water, and living resources can alter Earth system functioning, and potentially undermine the basis for the sustainability of our societies. Human activities have greatly increased the flows of reactive forms of nitrogen (N) and phosphorus (P) in the Earth system. These non-substitutable nutrient elements play a fundamental role in the human food system. Furthermore, the current mode of social and economic globalization, and its effect on the present-day energy system, also has large effects including large NOx-N emissions through combustion. Until now, this perturbation of N and P cycles has been treated largely as a local/regional issue, and managed in terms of direct impacts (water, land or air pollution). However, anthropogenic N and P cycle changes affect physical Earth system feedbacks (through greenhouse gas and aerosol changes) and biogeochemical feedbacks (via ecosystem changes, links to the carbon cycle, and altered nutrient limitation) with impacts that can be far removed from the direct sources. While some form of N and P management at the global level seems likely to be needed for continued societal development, the current local-level and sectorial management is often problematically simplistic, as seen in the tensions between divergent N management needs for climate change mitigation, air pollution control, food production, and ecosystem conservation. We require a step change in understanding complex biogeochemical, physical and socio-economic interactions in order to analyse these effects together, and inform policy trade-offs to minimize emergent systemic risks. Planetary boundaries for N and P cycle perturbation have recently been proposed. We discuss the current status of these precautionary boundaries and how we may improve on these preliminary assessments. We present an overview of the human perturbation of the global biogeochemical cycles of N and P and its interaction with the functioning of the

Water environments: anthropogenic pressures and ecosystem changes in the Atlantic drainage basins of Brazil.

Science.gov (United States)

Marques, Marcia; da Costa, Monica F; Mayorga, Maria Irles de O; Pinheiro, Patrícia R

2004-02-01

Densely occupied drainage basins and coastal zones in developing countries that are facing economic growth are likely to suffer from moderate to severe environmental impacts regarding different issues. The catchment basins draining towards the Atlantic coast from northeastern to southern Brazil include a wide range of climatic zones and diverse ecosystems. Within its borders lies the Atlantic rain forest, significant extensions of semiarid thorn forests (caatinga), vast tree and scrub woodlands (cerrado) and most of the 6670 km of the Brazilian coast and its marine ecosystems. In recent decades, human activities have increasingly advanced over these natural resources. Littoralization has imposed a burden on coastal habitats and communities. Most of the native vegetation of the cerrado and caatinga was removed and only 7% of the original Atlantic rainforest still exists. Estuaries, bays and coastal lagoons have been irreversibly damaged. Land uses, damming and water diversion have become the major driving forces for habitat loss and aquatic ecosystem modification. Regardless of the contrast between the drought-affected northeastern Brazil and the much more prosperous and industrialized southeastern/southern Brazil, the impacts on habitat and communities were found equally severe in both cases. Attempts to halt environmental degradation have not been effective. Instead of focusing on natural resources separately, it is suggested that more integrated environmental policies that focus on aquatic ecosystems integrity are introduced.

Nitrogen cycle and ecosystem services in the Brazilian La Plata Basin: anthropogenic influence and climate change.

Science.gov (United States)

Watanabe, M; Ortega, E; Bergier, I; Silva, J S V

2012-08-01

The increasing human demand for food, raw material and energy has radically modified both the landscape and biogeochemical cycles in many river basins in the world. The interference of human activities on the Biosphere is so significant that it has doubled the amount of reactive nitrogen due to industrial fertiliser production (Haber-Bosch), fossil fuel burning and land-use change over the last century. In this context, the Brazilian La Plata Basin contributes to the alteration of the nitrogen cycle in South America because of its huge agricultural and grazing area that meets the demands of its large urban centres - Sao Paulo, for instance - and also external markets abroad. In this paper, we estimate the current inputs and outputs of anthropogenic nitrogen (in kg N.km(-2).yr(-1)) in the basin. In the results, we observe that soybean plays a very important role in the Brazilian La Plata, since it contributes with an annual entrance of about 1.8 TgN due to biological nitrogen fixation. Moreover, our estimate indicates that the export of soybean products accounts for roughly 1.0 TgN which is greater than the annual nitrogen riverine exports from Brazilian Parana, Paraguay and Uruguay rivers together. Complimentarily, we built future scenarios representing changes in the nitrogen cycle profile considering two scenarios of climate change for 2070-2100 (based on IPCC's A2 and B2) that will affect land-use, nitrogen inputs, and loss of such nutrients in the basin. Finally, we discuss how both scenarios will affect human well-being since there is a connection between nitrogen cycle and ecosystem services that affect local and global populations, such as food and fibre production and climate regulation.

Nitrogen cycle and ecosystem services in the Brazilian La Plata Basin: anthropogenic influence and climate change

Directory of Open Access Journals (Sweden)

M Watanabe

Full Text Available The increasing human demand for food, raw material and energy has radically modified both the landscape and biogeochemical cycles in many river basins in the world. The interference of human activities on the Biosphere is so significant that it has doubled the amount of reactive nitrogen due to industrial fertiliser production (Haber-Bosch, fossil fuel burning and land-use change over the last century. In this context, the Brazilian La Plata Basin contributes to the alteration of the nitrogen cycle in South America because of its huge agricultural and grazing area that meets the demands of its large urban centres - Sao Paulo, for instance - and also external markets abroad. In this paper, we estimate the current inputs and outputs of anthropogenic nitrogen (in kg N.km-2.yr-1 in the basin. In the results, we observe that soybean plays a very important role in the Brazilian La Plata, since it contributes with an annual entrance of about 1.8 TgN due to biological nitrogen fixation. Moreover, our estimate indicates that the export of soybean products accounts for roughly 1.0 TgN which is greater than the annual nitrogen riverine exports from Brazilian Parana, Paraguay and Uruguay rivers together. Complimentarily, we built future scenarios representing changes in the nitrogen cycle profile considering two scenarios of climate change for 2070-2100 (based on IPCC's A2 and B2 that will affect land-use, nitrogen inputs, and loss of such nutrients in the basin. Finally, we discuss how both scenarios will affect human well-being since there is a connection between nitrogen cycle and ecosystem services that affect local and global populations, such as food and fibre production and climate regulation.

CLASSIFICATION OF ANTHROPOGENIC TRANSFORMATIONS SOILS URBOECOSYSTEMS OF DNEPROPETROVSK

Directory of Open Access Journals (Sweden)

YAKOVYSHYNA T.F.

2015-12-01

Full Text Available Raising of problem. The functioning of the city, as artificially created system of the result of the anthropogenic activity, promotes degradation and, sometimes, destruction of the environment, with change it to the technogenic replacement. First of all suffers the soil, as a basic component of any ecosystem, where the circulation of materials close, because it is a powerful biogeochemical barrier to their migration, able to deposit toxicants a long time through its protective functions. The leading role of the formation of the urban soil plays an anthropogenic factor, which is able to influence directly – the destruction of the soil profile due to construction activity and indirectly – with aerogenic or hydrogenous pollution xenobiotics contained in the emissions and discharges of the industrial enterprises; and it is determined by the type of economic use and history of area developing. The variability of using the urban soil is reflected in the soil profile and contributed to the creation of the organic-mineral layer by the mixing, mound, burial and (or contamination of the different substances on the surface. Therefore, classification of the urban soils by the anthropogenic destruction degree of the soil profile is very important scientific and practical task for the urban ecology to the achievement standards of the ecological safety of the modern city, because the restoring of their protective functions is impossible without knowledge of the morphological structure. Purpose. Classify the anthropogenical soils of city Dnipropetrovsk disturbed by the construction activities by the determining of the morphological characteristics of the soil profile structure with separation of the anthropogenic and technogenic surface formations compared to the zonal soil – ordinery chernozem. Conclusion. Within urboecosystem city Dnipropetrovsk long-term human impact to the zonal soil – chernozem led to its transformation into urbanozem witch

Natural and Anthropogenically Perturbed Biogenic Aerosol over Tropical South East Asia

Science.gov (United States)

Coe, H.; Robinson, N.; Allan, J. D.; Hewitt, C. N.

2014-12-01

Tropical forested regions are of interest as sources of atmospheric aerosol since they cover very large areas of the tropics and are a source of a large amount of volatile organic compounds which act as precursors for particle formation. Natural forest regions offer the potential to study the background state of the tropics and so potentially gain some insight into the pre-perturbed atmosphere. However, over the last decade in South East Asia, a considerable fraction of the native tropical deciduous forest has been deforested and replanted with palm oil plantations. This changes the range of volatile organic compounds that are emitted and act as sources of secondary organic aerosol. A suite of intensive ground and airborne measurements were made over both tropical forest and oil palm plantations in Sabah, Malaysia as part of the "Oxidant and Particle Photochemical Processes above a South East Asian tropical rainforest (OP3) during 2008. These data will be used together with recent improvements in our understanding of aerosol formation from biogenic compounds to discuss aerosol formation in tropical regions and the influence of human influence through widespread palm oil agriculture.

Tritium in water ecosystems of Ural

International Nuclear Information System (INIS)

Chebotina, M.Ya.; Nikolin, O.A.

2005-01-01

The paper provides the data on tritium monitoring in water ecosystems of the Ural region. The study area comprises the Beloyarsk Atomic Power Plant (cooling reservoir and the Olkhovsk bog-river ecosystem), a territory around the 'Mayak' Enterprise, and control territory, for comparison, located in the North of Sverdlovsk region. It was found that a large area in the Ural region, particularly near the power plant and the 'Mayak,, was characterized by increased tritium content in water as compared with technogenic background is typical for control areas. It may be considered that nearly all the tritium within the study area including control ones are of anthropogenic origin taking into account the act that the global background level for the radionuclide is 1 Bq/l.(author)

Are seagrass beds indicators of anthropogenic nutrient stress in the rocky intertidal?

International Nuclear Information System (INIS)

Honig, Susanna E.; Mahoney, Brenna; Glanz, Jess S.; Hughes, Brent B.

2017-01-01

It is well established that anthropogenic nutrient inputs harm estuarine seagrasses, but the influence of nutrients in rocky intertidal ecosystems is less clear. In this study, we investigated the effect of anthropogenic nutrient loading on Phyllospadix spp., a rocky intertidal seagrass, at local and regional scales. At sites along California, Washington, and Oregon, we demonstrated a significant, negative correlation of urban development and Phyllospadix bed thickness. These results were echoed locally along an urban gradient on the central California coast, where Phyllospadix shoot δ 15 N was negatively associated with Phyllospadix bed thickness, and experimentally, where nutrient additions in mesocosms reduced Phyllospadix shoot formation and increased epiphytic cover on Phyllospadix shoots. These findings provide evidence that coastal development can threaten rocky intertidal seagrasses through increased epiphytism. Considering that seagrasses provide vital ecosystem services, mitigating eutrophication and other factors associated with development in the rocky intertidal coastal zone should be a management priority. - Highlights: • The effect of nutrient loading on rocky intertidal seagrasses is not well studied. • Regionally, development was negatively associated with Phyllospadix bed thickness. • Locally, shoot δ 15 N was negatively associated with Phyllospadix bed thickness. • Mesocosms with added nutrients had a net loss in shoots and increased epiphytes. • Nutrient loading may have a negative effect on intertidal seagrass bed health.

Island biogeography and landscape structure: Integrating ecological concepts in a landscape perspective of anthropogenic impacts in temporary wetlands

International Nuclear Information System (INIS)

Angeler, David G.; Alvarez-Cobelas, Miguel

2005-01-01

Although our understanding of environmental risk assessment in temporary wetlands has been improved by the use of multi-species toxicity testing, we still know little of how landscape variables mediate the strength of, and recovery from, anthropogenic stress in such ecosystems. To bridge this research gap, we provide a theoretical framework of the response of temporary wetlands to anthropogenic disturbance along a habitat-isolation continuum based on island biogeography theory, landscape ecology and dispersal and colonization strategies of temporary wetland organisms. - Environmental risk assessment in temporary wetlands may benefit from consideration of island biogeography theory and landscape structure

Red Sea Acropora hemprichii Bacterial Population Dynamics under Adverse Anthropogenic Conditions

KAUST Repository

Lizcano, Javier

2012-08-01

Reef-building corals are cornerstones of life in the oceans. Understanding their interactions with microorganisms and their surrounding physicochemical conditions is important to comprehend reef functioning and ultimately protect coral reef ecosystems. Corals associate with a complex and specific array of microorganisms that supposedly affect their physiology and therefore can significantly determine the condition of a coral ecosystem. As environmental conditions may shape bacterial diversity and ecology in the coral symbiosis, ecosystem changes might have unfavorable consequences for the holobiont, to date poorly understood. Here, we were studying microbial community changes in A. hemprichii as a consequence of simulated eutrophication and overfishing over a period of 16 weeks by using in situ caging and slow release fertilizer treatments in an undisturbed Red Sea reef (22.18ºN, 38.57ºW). We used 16S rDNA amplicon sequencing to evaluate the individual and combined effects of overnutrification and fishing pressure, two of the most common local threats to coral reefs. With our data we hope to better understand bacterial population dynamics under anthropogenic influences and its role in coral resilience. Projecting further, this data will be useful to better predict the consequences of human activity on reef ecosystems.

A comparative analysis of hydrologic responses of tropical deciduous and temperate deciduous watershed ecosystems to climatic change

Science.gov (United States)

James M. Vose; Jose Manuel Maass

1999-01-01

Long-term monitoring of ecological and hydrological processes is critical to understanding ecosystem function and responses to anthropogenic and natural disturbances. Much of the world's knowledge of ecosystem responses to disturbance comes from long-term studies on gaged watersheds. However, there are relatively few long-term sites due to the large cost and...

Application of artificial intelligence to risk analysis for forested ecosystems

Science.gov (United States)

Daniel L. Schmoldt

2001-01-01

Forest ecosystems are subject to a variety of natural and anthropogenic disturbances that extract a penalty from human population values. Such value losses (undesirable effects) combined with their likelihoods of occurrence constitute risk. Assessment or prediction of risk for various events is an important aid to forest management. Artificial intelligence (AI)...

Anthropogenic shift of planktonic food web structure in a coastal lagoon by freshwater flow regulation

Science.gov (United States)

Hemraj, Deevesh A.; Hossain, A.; Ye, Qifeng; Qin, Jian G.; Leterme, Sophie C.

2017-03-01

Anthropogenic modification of aquatic systems has diverse impacts on food web interactions and ecosystem states. To reverse the adverse effects of modified freshwater flow, adequate management of discharge is required, especially due to higher water requirements and abstractions for human use. Here, we look at the effects of anthropogenically controlled freshwater flow regimes on the planktonic food web of a Ramsar listed coastal lagoon that is under recovery from degradation. Our results show shifts in water quality and plankton community interactions associated to changes in water flow. These shifts in food web interactions represent modifications in habitat complexity and water quality. At high flow, phytoplankton-zooplankton interactions dominate the food web. Conversely, at low flow, bacteria, viruses and nano/picoplankton interactions are more dominant, with a substantial switch of the food web towards heterotrophy. This switch can be associated with excess organic matter loading, decomposition of dead organisms, and synergistic and antagonistic interactions. We suggest that a lower variability in flow amplitude could be beneficial for the long-term sustaining of water quality and food web interactions, while improving the ecosystem health of systems facing similar stresses as the Coorong.

'Ecological value added' in an integrated ecosystem-economy model. An indicator for sustainability

International Nuclear Information System (INIS)

Kratena, Kurt

2004-01-01

This paper sets up an input-output system of the relevant ecosystem flows that determine the carbon cycle in the global ecosystem. Introducing energy as the value added component in the ecosystem allows to calculate ecosystem prices expressed in 'energy values'. Linking the ecosystem with the economy in an integrated input-output model then allows to calculate prices of economic activities and of ecosystem activities. In analogy to the 'Ecological Footprint', where productive land is needed to absorb anthropogenic emissions, in this integrated input-output model additional carbon sinks are introduced for emission absorption. These carbon sinks need solar energy input, i.e. 'ecological value added'. Emission absorption as well as GDP therefore become activities valued in the numeraire of the integrated system, i.e.'energy values'. From that sustainability indicators can be derived

Ecological consequences of human niche construction: Examining long-term anthropogenic shaping of global species distributions.

Science.gov (United States)

Boivin, Nicole L; Zeder, Melinda A; Fuller, Dorian Q; Crowther, Alison; Larson, Greger; Erlandson, Jon M; Denham, Tim; Petraglia, Michael D

2016-06-07

The exhibition of increasingly intensive and complex niche construction behaviors through time is a key feature of human evolution, culminating in the advanced capacity for ecosystem engineering exhibited by Homo sapiens A crucial outcome of such behaviors has been the dramatic reshaping of the global biosphere, a transformation whose early origins are increasingly apparent from cumulative archaeological and paleoecological datasets. Such data suggest that, by the Late Pleistocene, humans had begun to engage in activities that have led to alterations in the distributions of a vast array of species across most, if not all, taxonomic groups. Changes to biodiversity have included extinctions, extirpations, and shifts in species composition, diversity, and community structure. We outline key examples of these changes, highlighting findings from the study of new datasets, like ancient DNA (aDNA), stable isotopes, and microfossils, as well as the application of new statistical and computational methods to datasets that have accumulated significantly in recent decades. We focus on four major phases that witnessed broad anthropogenic alterations to biodiversity-the Late Pleistocene global human expansion, the Neolithic spread of agriculture, the era of island colonization, and the emergence of early urbanized societies and commercial networks. Archaeological evidence documents millennia of anthropogenic transformations that have created novel ecosystems around the world. This record has implications for ecological and evolutionary research, conservation strategies, and the maintenance of ecosystem services, pointing to a significant need for broader cross-disciplinary engagement between archaeology and the biological and environmental sciences.

Shifts in alpine lakes' ecosystems in Japan driven by increasing Asian dusts

Science.gov (United States)

Tsugeki, N. K.; Tani, Y.; Ueda, S.; Agusa, T.; Toyoda, K.; Kuwae, M.; Oda, H.; Tanabe, S.; Urabe, J.

2011-12-01

Recently in East Asia the amount of fossil fuel combustion have increased with economic growth. It has caused a problem of trans-boundary air pollution in the whole of eastern Asia. Furthermore, Asian dust storms contribute episodically to the global aerosol load. However, the effects of increased Asian dusts on aquatic ecosystems are not well understood. If biologically important nutrients such as nitrogen (N) and phosphorus (P) are transported via air dust, the atmospheric deposition of the dust may have serious impacts on recipient aquatic ecosystems because the biological production is limited by these nutrient elements. A previous report using sedimentary records has evaluated that atmospheric P inputs to the alpine lakes in the United States increased fivefold following the increased western settlement to this country during the nineteenth century. Since P is the most deficient nutrient for production in many lakes increase in P loading through atmospheric deposition of anthropogenically-derived dust might greatly affect the lake ecosystems. We examined fossil pigments and zooplankton remains from Pb-dated sediments taken from a high mountain lake of Hourai-Numa, located in the Towada-Hachimantai National Park of Japan, to uncover historical changes in the phyto- and zooplankton community over the past 100 years. Simultaneously, we measured the biogeochemical variables of TOC, TN, TP, δ13C, δ15N, and 206Pb/207Pb, 208Pb/207Pb in the sediments to identify environmental factors causing such changes. As a result, despite little anthropogenic activities in the watersheds, alpine lakes in Japan Islands increased algal and herbivore plankton biomasses by 3-6 folds for recent years depending on terrestrial the surrounded vegetations and landscape conditions. Biological and biogeochemical proxies recorded in the lake sediments indicate that this eutrophication occurred after the 1990s when P deposition increased due to atmospheric loading transported from Asian

The importance of benthic-pelagic coupling for marine ecosystem functioning in a changing world

DEFF Research Database (Denmark)

Griffiths, Jennifer R.; Kadin, Martina; Nascimento, Francisco J. A.

2017-01-01

and function is strongly affected by anthropogenic pressures, however there are large gaps in our understanding of the responses of inorganic nutrient and organic matter fluxes between benthic habitats and the water column. We illustrate the varied nature of physical and biological benthic-pelagic coupling...... processes and their potential sensitivity to three anthropogenic pressures - climate change, nutrient loading, and fishing - using the Baltic Sea as a case study, and summarize current knowledge on the exchange of inorganic nutrients and organic material between habitats. Traditionally measured benthic......Benthic-pelagic coupling is manifested as the exchange of energy, mass, or nutrients between benthic and pelagic habitats. It plays a prominent role in aquatic ecosystems and it is crucial to functions from nutrient cycling to energy transfer in food webs. Coastal and estuarine ecosystem structure...

Statistical partitioning of a three-year time series of direct urban net CO2 flux measurements into biogenic and anthropogenic components

Science.gov (United States)

Menzer, Olaf; McFadden, Joseph P.

2017-12-01

Eddy covariance flux measurements are increasingly used to quantify the net carbon dioxide exchange (FC) in urban areas. FC represents the sum of anthropogenic emissions, biogenic carbon release from plant and soil respiration, and carbon uptake by plant photosynthesis. When FC is measured in natural ecosystems, partitioning into respiration and photosynthesis is a well-established procedure. In contrast, few studies have partitioned FC at urban flux tower sites due to the difficulty of accounting for the temporal and spatial variability of the multiple sources and sinks. Here, we partitioned a three-year time series of flux measurements from a suburban neighborhood of Minneapolis-Saint Paul, Minnesota, USA. We segregated FC into one subset that captured fluxes from a residential neighborhood and into another subset that covered a golf course. For both land use types we modeled anthropogenic flux components based on winter data and extrapolated them to the growing season, to estimate gross primary production (GPP) and ecosystem respiration (Reco) at half-hourly, daily, monthly and annual scales. During the growing season, GPP had the largest magnitude (up to - 9.83 g C m-2 d-1) of any component CO2 flux, biogenic or anthropogenic, and both GPP and Reco were more dynamic seasonally than anthropogenic fluxes. Owing to the balancing of Reco against GPP, and the limitations of the growing season in a cold temperate climate zone, the net biogenic flux was only 1.5%-4.5% of the anthropogenic flux in the dominant residential land use type, and between 25%-31% of the anthropogenic flux in highly managed greenspace. Still, the vegetation sink at our site was stronger than net anthropogenic emissions on 16-20 days over the residential area and on 66-91 days over the recreational area. The reported carbon flux sums and dynamics are a critical step toward developing models of urban CO2 fluxes within and across cities that differ in vegetation cover.

Predicting the impacts of anthropogenic disturbances on marine populations

DEFF Research Database (Denmark)

Nabe-Nielsen, Jacob; van Beest, Floris; Grimm, Volker

Marine ecosystems are increasingly exposed to anthropogenic disturbances that cause animals to change behavior and move away from potential foraging grounds. Here we present a process-based modeling framework for assessing population consequences of such sub-lethal behavioral effects. It builds...... on how disturbances influence animal movements, and how this in turn affect their foraging and energetics. The animals’ tendency to move away from disturbances is directly related to the experienced noise level. The reduced foraging in noisy areas affects the animals’ energy budget, fitness...... that determine animal fitness, are expected to have high predictive power in novel environments, making them ideal tools for marine management....

Evaluation of anthropogenic influences on the Luhuitou fringing reef via spatial and temporal analyses (from isotopic values)

Science.gov (United States)

Cao, D.; Cao, W.; Yu, K.; Wu, G.; Yang, J.; Su, X.; Wang, F.

2017-05-01

Coral reefs have suffered remarkable declines worldwide. Nutrient overenrichment is considered to be one of the primary local causes. The Luhuitou fringing reef in southern China is a well-known tourist destination that is subject to enormous coastal renovation. The mean δ13C, δ15N value, and carbon over nitrogen ratio (C/N) of particulate organic matter were -21.56 ± 1.94‰, 7.04 ± 3.81‰, and 5.81 ± 1.86, respectively, suggesting mixed sources of carbon and nitrogen. The IsoError calculations suggested that marine phytoplankton and marine benthic algae dominated the majority of carbon sources, while anthropogenic and terrestrial organic nitrogen dominated the nitrogen sources. A tendency toward greater terrestrial detritus and anthropogenic-derived discharges was found during dry seasons and greater marine-derived organic matter during wet seasons. These results demonstrated the existence of anthropogenic influences and high dissolved inorganic nitrogen concentrations and C/N ratios. Anthropogenic nutrient discharge moderated nitrogen limitation, whereas phosphorus became more important to the reef ecosystem. Despite the marine carbon sources dominated, freshwater and terrestrial-derived organic carbon sources were also very important. Meanwhile, anthropogenic and terrestrial organic nitrogen sources were dominant. Therefore, pollution from more extensive region and anthropogenic activities from riverine sewage discharges adjacent to reefs should be focused to effectively reduce human-derived nutrients on reefs.

Comparing pristine and depleted ecosystems: The Sørfjord, Norway versus the Gulf of St. Lawrence, Canada. Effects of intense fisheries on marine ecosystems

Science.gov (United States)

Morissette, Lyne; Pedersen, Torstein; Nilsen, Marianne

2009-04-01

The Sørfjord, Norway, and the Gulf of St. Lawrence, Canada, are two sub-arctic ecosystems with similar trophic structure. However, in the Gulf of St. Lawrence, severe exploitation of groundfish stocks has lead to important shifts in the trophic structure. In the Sørfjord, the situation is different: fishing pressure is much lighter. Our hypothesis is that overexploitation leads to changes in the trophic structure and severely alters the resilience of ecosystems. Based on the same modelling approach ( Ecopath with Ecosim) the food web structure was compared, using different ecosystem indicators. Patterns of food web structure and trophodynamics were contrasted. Cod was the keystone species in both ecosystems, and forage fish were also important. Even after similar environmental changes in both ecosystems, and after a reduction of fishing pressure in the Gulf of St. Lawrence, there is no recovery of cod stocks in this ecosystem. In the Sørfjord, after different perturbations (but not from the fishery), the ecosystem seems to return to its equilibrium.

The Multifaceted Aspects of Ecosystem Integrity

Directory of Open Access Journals (Sweden)

Giulio A. De Leo

1997-06-01

Full Text Available The need to reduce human impacts on ecosystems creates pressure for adequate response, but the rush to solutions fosters the oversimplification of such notions as sustainable development and ecosystem health. Hence, it favors the tendency to ignore the complexity of natural systems. In this paper, after a brief analysis of the use and abuse of the notion of ecosystem health, we address the problem of a sound definition of ecosystem integrity, critically review the different methodological and conceptual approaches to the management of natural resources, and sketch the practical implications stemming from their implementation. We show thatthere are merits and limitations in different definitions of ecosystem integrity, for each acknowledges different aspects of ecosystem structure and functioning and reflects the subjective perspectives of humans on the value, importance, and role of biological diversity. This evaluation is based on a brief sketch of the links among biodiversity, ecosystem functioning and resilience, and a description of the problems that arise in distinguishing between natural and anthropogenic disturbance. We also emphasize the difficulty of assessing the economic value of species and habitats and the need to use adaptive management policies to deal with uncertainty and ecosystem complexity. In conclusion, while acknowledging that environmental legislation requires objective statements on ecosystem status and trends, we stress that the notion of ecological integrity is so complex that its measure cannot be expressed through a single indicator, but rather requires a set of indicators at different spatial, temporal, and hierarchical levels of ecosystem organization. Ecosystem integrity is not an absolute, monolithic concept. The existence of different sets of values regarding biological diversity and environmental risks must be explicitly accounted for and incorporated in the decision process, rather than ignored or averaged out.

The importance of benthic-pelagic coupling for marine ecosystem functioning in a changing world.

Science.gov (United States)

Griffiths, Jennifer R; Kadin, Martina; Nascimento, Francisco J A; Tamelander, Tobias; Törnroos, Anna; Bonaglia, Stefano; Bonsdorff, Erik; Brüchert, Volker; Gårdmark, Anna; Järnström, Marie; Kotta, Jonne; Lindegren, Martin; Nordström, Marie C; Norkko, Alf; Olsson, Jens; Weigel, Benjamin; Žydelis, Ramunas; Blenckner, Thorsten; Niiranen, Susa; Winder, Monika

2017-06-01

Benthic-pelagic coupling is manifested as the exchange of energy, mass, or nutrients between benthic and pelagic habitats. It plays a prominent role in aquatic ecosystems, and it is crucial to functions from nutrient cycling to energy transfer in food webs. Coastal and estuarine ecosystem structure and function are strongly affected by anthropogenic pressures; however, there are large gaps in our understanding of the responses of inorganic nutrient and organic matter fluxes between benthic habitats and the water column. We illustrate the varied nature of physical and biological benthic-pelagic coupling processes and their potential sensitivity to three anthropogenic pressures - climate change, nutrient loading, and fishing - using the Baltic Sea as a case study and summarize current knowledge on the exchange of inorganic nutrients and organic material between habitats. Traditionally measured benthic-pelagic coupling processes (e.g., nutrient exchange and sedimentation of organic material) are to some extent quantifiable, but the magnitude and variability of biological processes are rarely assessed, preventing quantitative comparisons. Changing oxygen conditions will continue to have widespread effects on the processes that govern inorganic and organic matter exchange among habitats while climate change and nutrient load reductions may have large effects on organic matter sedimentation. Many biological processes (predation, bioturbation) are expected to be sensitive to anthropogenic drivers, but the outcomes for ecosystem function are largely unknown. We emphasize how improved empirical and experimental understanding of benthic-pelagic coupling processes and their variability are necessary to inform models that can quantify the feedbacks among processes and ecosystem responses to a changing world. © 2017 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.

The impacts of past climate change on terrestrial and aquatic ecosystems

International Nuclear Information System (INIS)

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

2001-01-01

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

Isotopic evidence for anthropogenic impacts on aquatic food web dynamics and mercury cycling in a subtropical wetland ecosystem in the US

Energy Technology Data Exchange (ETDEWEB)

Wang, Yang, E-mail: ywang@magnet.fsu.edu [Department of Earth, Ocean and Atmospheric Science, Florida State University and National High Magnetic Field Laboratory, Tallahassee, FL 32306–4100 (United States); Gu, Binhe [South Florida Water Management District, West Palm Beach, FL 33406 (United States); Lee, Ming-Kuo [Department of Geology and Geography, Auburn University, Auburn, AL 36839 (United States); Jiang, Shijun, E-mail: sjiang@jnu.edu.cn [Institute of Hydrobiology/Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, Jinan University, Guangzhou, Guangdong 510632 (China); Xu, Yingfeng [Department of Earth, Ocean and Atmospheric Science, Florida State University and National High Magnetic Field Laboratory, Tallahassee, FL 32306–4100 (United States)

2014-07-01

Quantifying and predicting the food web consequences of anthropogenic changes is difficult using traditional methods (based on gut content analysis) because natural food webs are variable and complex. Here, stable and radioactive carbon isotopes are used, in conjunction with nitrogen isotopes and mercury (Hg) concentration data, to document the effects of land-use change on food webs and Hg bioaccumulation in the Everglades – a subtropical wetland ecosystem in the US. Isotopic signatures of largemouth bass and sunfish in reference (relatively pristine) wetlands indicate reliance on the food supply of modern primary production within the wetland. In contrast, both fish in areas impacted by agricultural runoff had radiocarbon ages as old as 540 years B.P., and larger isotopic variability than counterparts in reference wetlands, reflecting differences in the food web between impacted and reference wetlands. Consistent with this difference, particulate and dissolved organic matter in impacted areas had old radiocarbon ages (> 600 years B.P.), indicating that old carbon derived from historic peat deposits in the Everglades Agricultural Area was passed along the food chain to consumers. Significant radiocarbon deficiencies in largemouth bass and sunfish, relative to mosquitofish, in impacted areas most likely indicate a reduced dependence on small fish. Furthermore, largemouth bass and sunfish from impacted areas had much lower Hg contents than those from reference wetlands. Taken together, these data suggest a shift toward lower trophic levels and a possible reduction in mercury methylation in impacted wetlands. Our study provides clear evidence that hydrological modification and land-use change in the Everglades have changed the system from one driven primarily by in-situ productivity to one that is partially dependent on allochthonous carbon input from peat soils in the agricultural area and altered the Hg biogeochemical cycle in the wetlands. The results have

Isotopic evidence for anthropogenic impacts on aquatic food web dynamics and mercury cycling in a subtropical wetland ecosystem in the US

International Nuclear Information System (INIS)

Wang, Yang; Gu, Binhe; Lee, Ming-Kuo; Jiang, Shijun; Xu, Yingfeng

2014-01-01

Quantifying and predicting the food web consequences of anthropogenic changes is difficult using traditional methods (based on gut content analysis) because natural food webs are variable and complex. Here, stable and radioactive carbon isotopes are used, in conjunction with nitrogen isotopes and mercury (Hg) concentration data, to document the effects of land-use change on food webs and Hg bioaccumulation in the Everglades – a subtropical wetland ecosystem in the US. Isotopic signatures of largemouth bass and sunfish in reference (relatively pristine) wetlands indicate reliance on the food supply of modern primary production within the wetland. In contrast, both fish in areas impacted by agricultural runoff had radiocarbon ages as old as 540 years B.P., and larger isotopic variability than counterparts in reference wetlands, reflecting differences in the food web between impacted and reference wetlands. Consistent with this difference, particulate and dissolved organic matter in impacted areas had old radiocarbon ages (> 600 years B.P.), indicating that old carbon derived from historic peat deposits in the Everglades Agricultural Area was passed along the food chain to consumers. Significant radiocarbon deficiencies in largemouth bass and sunfish, relative to mosquitofish, in impacted areas most likely indicate a reduced dependence on small fish. Furthermore, largemouth bass and sunfish from impacted areas had much lower Hg contents than those from reference wetlands. Taken together, these data suggest a shift toward lower trophic levels and a possible reduction in mercury methylation in impacted wetlands. Our study provides clear evidence that hydrological modification and land-use change in the Everglades have changed the system from one driven primarily by in-situ productivity to one that is partially dependent on allochthonous carbon input from peat soils in the agricultural area and altered the Hg biogeochemical cycle in the wetlands. The results have

Landscape anthropogenic disturbance in the Mediterranean ecosystem: is the current landscape sustainable?

Science.gov (United States)

Biondi, Guido; D'Andrea, Mirko; Fiorucci, Paolo; Franciosi, Chiara; Lima, Marco

2013-04-01

Mediterranean landscape during the last centuries has been subject to strong anthropogenic disturbances who shifted natural vegetation cover in a cultural landscape. Most of the natural forest were destroyed in order to allow cultivation and grazing activities. In the last century, fast growing conifer plantations were introduced in order to increase timber production replacing slow growing natural forests. In addition, after the Second World War most of the grazing areas were changed in unmanaged mediterranean conifer forest frequently spread by fires. In the last decades radical socio economic changes lead to a dramatic abandonment of the cultural landscape. One of the most relevant result of these human disturbances, and in particular the replacement of deciduous forests with coniferous forests, has been the increasing in the number of forest fires, mainly human caused. The presence of conifers and shrubs, more prone to fire, triggered a feedback mechanism that makes difficult to return to the stage of potential vegetation causing huge economic, social and environmental damages. The aim of this work is to investigate the sustainability of the current landscape. A future landscape scenario has been simulated considering the natural succession in absence of human intervention assuming the current fire regime will be unaltered. To this end, a new model has been defined, implementing an ecological succession model coupled with a simply Forest Fire Model. The ecological succession model simulates the vegetation dynamics using a rule-based approach discrete in space and time. In this model Plant Functional Types (PFTs) are used to describe the landscape. Wildfires are randomly ignited on the landscape, and their propagation is simulated using a stochastic cellular automata model. The results show that the success of the natural succession toward a potential vegetation cover is prevented by the frequency of fire spreading. The actual landscape is then unsustainable

Biodiversity, Ecosystem Services, and Climate Change : The Economic Problem

OpenAIRE

World Bank

2010-01-01

Climate change is both a cause and an effect of biodiversity change. Along with anthropogenic dispersion, climate change is the main driver of change in the geographical distribution of both beneficial and harmful species, crops, livestock, harvested wild species, pests, predators and pathogens. And the capacity of ecosystems to adapt to climate change depends on the diversity of species t...

Human impact on lake ecosystems: the case of Lake Naivasha, Kenya

African Journals Online (AJOL)

Lake Naivasha is a wetland of national and international importance. However, it is under constant anthropogenic pressures, which include the quest for socioeconomic development within the lake ecosystem itself as well as other activities within the catchment. The lake is an important source of fresh water in an otherwise ...

Assessment of the effect of anthropogenic pollution on the ecology of small shallow lakes using the palaeolimnological approach

Directory of Open Access Journals (Sweden)

Tiiu Koff

2016-11-01

Full Text Available Palaeolimnological techniques were utilized to determine the extent of the effect of anthropogenic pollutants or other environmental stressors on three lake ecosystems over the last 200 years. The ecology of the study sites has experienced significant changes due to various activities such as (1 extensive catchment drainage and using poisoning as a fish management measure, (2 seepage of urban waste water due to establishment and growth of a town and (3 artificial inflow of oil-shale mining waters. Sediment geochemical composition, fossil pigments and Cladocera remains from the sediment cores were analysed to demonstrate that sufficient information can be derived from sediments to permit a historical reconstruction. The integrated use of archival maps, historical records and lake monitoring data confirmed links to anthropogenic pollutants, primarily on the catchment level. The examples show how the sediment indicators provide unique insights into the causes and temporal dynamics of lake ecosystem changes relevant for environmental management decisions. This study demonstrates that palaeolimnology has great potential to assist in eutrophication assessment and management efforts in waterbodies.

Toward Understanding, Managing, and Protecting Microbial Ecosystems

Science.gov (United States)

Bodelier, Paul L. E.

2011-01-01

Microbial communities are at the very basis of life on earth, catalyzing biogeochemical reactions driving global nutrient cycles. However, unlike for plants and animals, microbial diversity is not on the biodiversity–conservation agenda. The latter, however, would imply that microbial diversity is not under any threat by anthropogenic disturbance or climate change. This maybe a misconception caused by the rudimentary knowledge we have concerning microbial diversity and its role in ecosystem functioning. This perspective paper identifies major areas with knowledge gaps within the field of environmental microbiology that preclude a comprehension of microbial ecosystems on the level we have for plants and animals. Opportunities and challenges are pointed out to open the microbial black box and to go from descriptive to predictive microbial ecology. PMID:21747797

Network Skewness Measures Resilience in Lake Ecosystems

Science.gov (United States)

Langdon, P. G.; Wang, R.; Dearing, J.; Zhang, E.; Doncaster, P.; Yang, X.; Yang, H.; Dong, X.; Hu, Z.; Xu, M.; Yanjie, Z.; Shen, J.

2017-12-01

Changes in ecosystem resilience defy straightforward quantification from biodiversity metrics, which ignore influences of community structure. Naturally self-organized network structures show positive skewness in the distribution of node connections. Here we test for skewness reduction in lake diatom communities facing anthropogenic stressors, across a network of 273 lakes in China containing 452 diatom species. Species connections show positively skewed distributions in little-impacted lakes, switching to negative skewness in lakes associated with human settlement, surrounding land-use change, and higher phosphorus concentration. Dated sediment cores reveal a down-shifting of network skewness as human impacts intensify, and reversal with recovery from disturbance. The appearance and degree of negative skew presents a new diagnostic for quantifying system resilience and impacts from exogenous forcing on ecosystem communities.

Towards understanding, managing and protecting microbial ecosystems

Directory of Open Access Journals (Sweden)

Paul eBodelier

2011-04-01

Full Text Available Microbial communities are at the very basis of life on earth, catalysing biogeochemical reactions driving global nutrient cycles. However, unlike for plants and animals, microbial diversity is not on the biodiversity conservation agenda. The latter, however, would imply that microbial diversity is not under any threat by anthropogenic disturbance or climate change. This maybe a misconception caused by the rudimentary knowledge we have concerning microbial diversity and its role in ecosystem functioning. This perspective paper indentifies major areas with knowledge gaps within the field of environmental microbiology that preclude a comprehension of microbial ecosystems on the level we have for plants and animals. Opportunities and challenges are pointed out to open the microbial black box and to go from descriptive to predictive microbial ecology.

Toward understanding, managing, and protecting microbial ecosystems.

Science.gov (United States)

Bodelier, Paul L E

2011-01-01

Microbial communities are at the very basis of life on earth, catalyzing biogeochemical reactions driving global nutrient cycles. However, unlike for plants and animals, microbial diversity is not on the biodiversity-conservation agenda. The latter, however, would imply that microbial diversity is not under any threat by anthropogenic disturbance or climate change. This maybe a misconception caused by the rudimentary knowledge we have concerning microbial diversity and its role in ecosystem functioning. This perspective paper identifies major areas with knowledge gaps within the field of environmental microbiology that preclude a comprehension of microbial ecosystems on the level we have for plants and animals. Opportunities and challenges are pointed out to open the microbial black box and to go from descriptive to predictive microbial ecology.

Isotope Investigations of Nitrogen Compounds in Different Aquatic Ecosystems in Cyprus, Russia and Ukraine

Energy Technology Data Exchange (ETDEWEB)

Voropaev, A.; Voerkelius, S.; Eichinger, L. [Hydroisotop GmbH, Schweitenkirchen (Germany); Grinenko, V. [Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, Moscow (Russian Federation)

2013-07-15

The isotope analyses of nitrogen compounds is a powerful tool for the investigation of anrthropogenic influence on the nitrogen cycle in terrestrial and aquatic ecosystems. The isotopic composition of nitrogen and oxygen in nitrates from different groundwater aquifers in Cyprus reflects anthropogenic inputs of nitrogen mainly from industrial fertilizer application in agriculture. Significant denitrification as identified at many sampling sites is an important process, which reduces nitrate concentrations in groundwater. In surface water ecosystems anthropogenic influences and natural environmental changes are detected by the isotopic composition of nitrogen in suspended organic material and in bottom sediments. In the oligotrophic fresh water of Lake Galich in Russia the waste water outflow is a reason for the local increase of {delta}{sup 15}N values in bottom sediments, where the nitrogen and carbon isotopic compositions of unpolluted sediments are very homogeneous. In the Neva estuary in russia the lateral destribution of {delta}{sup 15}N values in upper layers of bottom sediments reflects changes in the mixing pattern of marine and continental organic matter caused by a flood protection dam building in the Dneprovsko-Bugsky estuary in Ukraine - probably the increasing influence of anthropogenic {sup 15}N enriched nutrient load. (author)

Anthropogenic disturbances jeopardize biodiversity conservation within tropical rainforest reserves.

Science.gov (United States)

Martínez-Ramos, Miguel; Ortiz-Rodríguez, Iván A; Piñero, Daniel; Dirzo, Rodolfo; Sarukhán, José

2016-05-10

Anthropogenic disturbances affecting tropical forest reserves have been documented, but their ecological long-term cumulative effects are poorly understood. Habitat fragmentation and defaunation are two major anthropogenic threats to the integrity of tropical reserves. Based on a long-term (four decades) study, we document how these disturbances synergistically disrupt ecological processes and imperil biodiversity conservation and ecosystem functioning at Los Tuxtlas, the northernmost tropical rainforest reserve in the Americas. Deforestation around this reserve has reduced the reserve to a medium-sized fragment (640 ha), leading to an increased frequency of canopy-gap formation. In addition, hunting and habitat loss have caused the decline or local extinction of medium and large herbivores. Combining empirical, experimental, and modeling approaches, we support the hypothesis that such disturbances produced a demographic explosion of the long-lived (≈120 y old, maximum height of 7 m) understory palm Astrocaryum mexicanum, whose population has increased from 1,243-4,058 adult individuals per hectare in only 39 y (annual growth rate of ca 3%). Faster gap formation increased understory light availability, enhancing seed production and the growth of immature palms, whereas release from mammalian herbivory and trampling increased survival of seedlings and juveniles. In turn, the palm's demographic explosion was followed by a reduction of tree species diversity, changing forest composition, altering the relative contribution of trees to forest biomass, and disrupting litterfall dynamics. We highlight how indirect anthropogenic disturbances (e.g., palm proliferation) on otherwise protected areas threaten tropical conservation, a phenomenon that is currently eroding the planet's richest repositories of biodiversity.

Prehistoric Human-environment Interactions and Their Impact on Aquatic Ecosystems

Science.gov (United States)

Mackay, H.; Henderson, A. C. G.; van Hardenbroek, M.; Cavers, G.; Crone, A.; Davies, K. L.; Fonville, T. R.; Head, K.; Langdon, P. G.; Matton, R.; McCormick, F.; Murray, E.; Whitehouse, N. J.; Brown, A. G.

2017-12-01

One of the first widespread human-environment interactions in Scotland and Ireland occurred 3000 years ago when communities first inhabited wetlands, building artificial islands in lakes called crannogs. The reason behind the development and intermittent occupation of crannogs is unclear. We don't know if they were a response to changes in environment or if they were driven by societal influences. Furthermore, the impact of the construction, settlement and human activities on lake ecosystems is unknown, but is a key example of early anthropogenic signatures on the environment. Our research characterises the prehistoric human-environment interactions associated with crannogs by analysing geochemical and biological signals preserved within the crannog and wetland sediments. Records of anthropogenic activities and environmental change have been produced using lipid biomarkers of faecal matter, sedimentary DNA, and the remains of beetles, aquatic invertebrates (chironomids), siliceous algae (diatoms) and pollen. Results of these analyses reveal settlement occupations occurred in phases from the Iron Age to the Medieval Period. The main effects of occupation on the wetland ecosystems are nutrient-driven increases in productivity and shifts in aquatic species from clear water taxa to those associated with more eutrophic conditions. Crannog abandonment reduces nutrient inputs and therefore levels of aquatic productivity, as evidenced by decreases in the abundance of siliceous algae. Despite returns to pre-settlement nutrient and productivity levels, the lake ecosystems do not recover to their previous ecological state: dominant aquatic invertebrate and siliceous algae taxa shift in response to elevated levels of macrophytes within the lakes. Whilst these phase changes in lake ecosystems highlight their adaptive capacity to environmental change, the temporary human interactions associated with crannogs had persisting environmental impacts that shaped the long

Growing population and ecosystem change increase human schistosomiasis around Lake Malaŵi.

Science.gov (United States)

Van Bocxlaer, Bert; Albrecht, Christian; Stauffer, Jay R

2014-05-01

Multiple anthropogenic environmental stressors with reinforcing effects to the deterioration of ecosystem stability can obscure links between ecosystem change and the prevalence of infectious diseases. Incomplete understanding may lead to ineffective public health and disease control strategies, as appears to be the case with increased urogenital schistosomiasis in humans around Lake Malaŵi over recent decades. Sedimentation and eutrophication help explain historical changes in intermediate host range and parasite transmission. Hence, control strategies should account for abiotic changes. Copyright © 2014 Elsevier Ltd. All rights reserved.

21st Century Rise in Anthropogenic Nitrogen Deposition on a Remote Coral Reef

Science.gov (United States)

Ren, H. A.; Chen, Y. C.; Wang, X. T.; Wong, G. T. F.; Cohen, A. L.; DeCarlo, T. M.; Weigand, M. A.; Mii, H. S.; Sigman, D. M.

2017-12-01

With the rapid rise in pollution-associated nitrogen inputs to the western Pacific, it has been suggested that even the open ocean has been impacted through atmospheric deposition. In a coral core from Dongsha Atoll, a coral reef ecosystem 340 km from the nearest continent, we observe a decline in the 15N/14N of coral skeleton-bound organic matter, signaling increased deposition of anthropogenic atmospheric N on the open ocean and its incorporation into plankton and in turn the corals living on the atoll. The decrease began just several years before 2000 CE, decades later than predicted by other work, and the amplitude of decline suggests that anthropogenic atmospheric N input is now 20±5% of the annual N input to the surface ocean in this region, less than two-thirds of that estimated by models and analyses of nutrient ratio changes.

Stability measures in arid ecosystems

Science.gov (United States)

Nosshi, M. I.; Brunsell, N. A.; Koerner, S.

2015-12-01

Stability, the capacity of ecosystems to persist in the face of change, has proven its relevance as a fundamental component of ecological theory. Here, we would like to explore meaningful and quantifiable metrics to define stability, with a focus on highly variable arid and semi-arid savanna ecosystems. Recognizing the importance of a characteristic timescale to any definition of stability, our metrics will be focused scales from annual to multi-annual, capturing different aspects of stability. Our three measures of stability, in increasing order of temporal scale, are: (1) Ecosystem resistance, quantified as the degree to which the system maintains its mean state in response to a perturbation (drought), based on inter-annual variability in Normalized Difference Vegetation Index (NDVI). (2) An optimization approach, relevant to arid systems with pulse dynamics, that models vegetation structure and function based on a trade off between the ability to respond to resource availability and avoid stress. (3) Community resilience, measured as species turnover rate (β diversity). Understanding the nature of stability in structurally-diverse arid ecosystems, which are highly variable, yields theoretical insight which has practical implications.

″The Anthropocene″, Ecosystem Management, and Environmental Virtue.

Science.gov (United States)

Sandler, Ronald

2016-01-01

*Portions of this article are drawn from: Sandler, R. Environmental Ethics: Theory in Practice, Oxford University Press, New York, in press. In this article I consider contrasting views on the implications of rapid, macroscale anthropogenic change for environmental ethics, particularly ecosystem management, species conservation, and environmental virtue. I begin by reviewing the Anthropocene debate, which has become a primary point of discourse on whether we ought to embrace a more interventionist stance regarding ecosystem management and species conservation. I then discuss the challenges posed by rapid ecological change to predominant ecosystem management and species conservation practices. I argue that these challenges not withstanding, we ought not go all in on interventionist management, even as novel conservation and management techniques can be justified in particular cases. It is possible to adopt a more forward looking normative stance, without licensing robust interventionism. Finally, I discuss the implications of this for some environmental virtues.

Strategies for conservation of endangered ecosystems

International Nuclear Information System (INIS)

Ashraf, M.; Hussain, M.; Ahmad, M.S.A.

2012-01-01

The planet Earth is known to host a rich biodiversity owing to its suitable environmental conditions for life and at a larger scale it is regarded as a major ecosystem. Healthy existence of living organisms in this ecosystem depends on proper functioning of all the associated environmental factors. Since millennia, living organisms have adapted to thrive under a limited range of environmental conditions. Nevertheless previous history of the earth and fossil records indicates that the biodiversity housed by the planet earth has experienced five major catastrophic extinctions due to change in physical environment. Even currently, it is undergoing sixth major extinction event mainly due to anthropogenic activities. The human activities are proving a dual menace for biodiversity. On the one hand, it is causing habitat loss through intensive deforestation, conversion of different natural plant communities for agriculture, and urbanization and industrialization. Moreover, it is resulting in habitat degradation by polluting both terrestrial and aquatic ecosystems, emitting air pollutants resulting in acid rains, ozone layer depletion, global warming, heavy metal contamination and eutrophication of water bodies. As a result, healthy existence of both terrestrial and aquatic ecosystems and their associated biodiversity is altogether threatened. Worldwide efforts are underway to conserve the threatened ecosystems and their related biodiversity. A number of international conventions have been held to conserve natural ecosystems. Pakistan being a signatory of these conventions has its obligation to join hands with international community to conserve the endangered ecosystems within as well as outside its bounds. Under the existing scenario the objective of organizing this symposium was to pinpoint the threats to endangered ecosystems of the world in general and those in Pakistan in particular, and to develop suitable strategies for conservation of such paralyzed ecosystems

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

Science.gov (United States)

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

2017-02-10

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

Tracing the recently increasing anthropogenic Pb inputs into the East China Sea shelf sediments using Pb isotopic analysis

International Nuclear Information System (INIS)

Wang, Deli; Zhao, Zhiqi; Dai, Minhan

2014-01-01

Highlights: • Lithogenic Pb dominated in the ECS shelf sediments. • Small but increasing anthropogenic Pb occurred in the ECS shelf sediments. • HCl-leachated Pb suggested a source from “polluted” coastal sediments. • Residual Pb was mainly contributed from the “pristine” upper Yangtze watershed. - Abstract: This study examined the Pb content and Pb isotopic composition in a sediment core taken from the East China Sea (ECS) shelf, and it was observed that since 2003 the increasing anthropogenic Pb inputs have impacted as far as the ECS shelf sediments. The ECS shelf sediments were generally characterized with low bulk Pb contents (12.5–15.0 μg/g) and relatively lithogenic Pb isotopic signatures (both HCl-leached and residual fractions). However, elevated Pb records along with lighter Pb isotopic signals have occurred in the post-2003 sediments, as a result of a small but increasing anthropogenic Pb contribution from the heavily human perturbed coastal sediments due to the sharply increasing coal consumption in mainland China since 2003

Anthropogenic sulfur dioxide emissions: 1850–2005

Directory of Open Access Journals (Sweden)

S. J. Smith

2011-02-01

Full Text Available Sulfur aerosols impact human health, ecosystems, agriculture, and global and regional climate. A new annual estimate of anthropogenic global and regional sulfur dioxide emissions has been constructed spanning the period 1850–2005 using a bottom-up mass balance method, calibrated to country-level inventory data. Global emissions peaked in the early 1970s and decreased until 2000, with an increase in recent years due to increased emissions in China, international shipping, and developing countries in general. An uncertainty analysis was conducted including both random and systemic uncertainties. The overall global uncertainty in sulfur dioxide emissions is relatively small, but regional uncertainties ranged up to 30%. The largest contributors to uncertainty at present are emissions from China and international shipping. Emissions were distributed on a 0.5° grid by sector for use in coordinated climate model experiments.

Trophic cascades triggered by overfishing reveal possible mechanisms of ecosystem regime shifts.

Science.gov (United States)

Daskalov, Georgi M; Grishin, Alexander N; Rodionov, Sergei; Mihneva, Vesselina

2007-06-19

Large-scale transitions between alternative states in ecosystems are known as regime shifts. Once described as healthy and dominated by various marine predators, the Black Sea ecosystem by the late 20th century had experienced anthropogenic impacts such as heavy fishing, cultural eutrophication, and invasions by alien species. We studied changes related to these "natural experiments" to reveal the mechanisms of regime shifts. Two major shifts were detected, the first related to a depletion of marine predators and the second to an outburst of the alien comb jelly Mnemiopsis leidyi; both shifts were triggered by intense fishing resulting in system-wide trophic cascades. The complex nature of ecosystem responses to human activities calls for more elaborate approaches than currently provided by traditional environmental and fisheries management. This implies challenging existing practices and implementing explanatory models of ecosystem interactions that can better reconcile conservation and ecosystem management ideals.

[Impacts of hydroelectric cascade exploitation on river ecosystem and landscape: a review].

Science.gov (United States)

Yang, Kun; Deng, Xi; Li, Xue-Ling; Wen, Ping

2011-05-01

Hydroelectric cascade exploitation, one of the major ways for exploiting water resources and developing hydropower, not only satisfies the needs of various national economic sectors, but also promotes the socio-economic sustainable development of river basin. unavoidable anthropogenic impacts on the entire basin ecosystem. Based on the process of hydroelectric cascade exploitation and the ecological characteristics of river basins, this paper reviewed the major impacts of hydroelectric cascade exploitation on dam-area ecosystems, river reservoirs micro-climate, riparian ecosystems, river aquatic ecosystems, wetlands, and river landscapes. Some prospects for future research were offered, e.g., strengthening the research of chain reactions and cumulative effects of ecological factors affected by hydroelectric cascade exploitation, intensifying the study of positive and negative ecological effects under the dam networks and their joint operations, and improving the research of successional development and stability of basin ecosystems at different temporal and spatial scales.

Future Climate Impacts of Direct Radiative Forcing Anthropogenic Aerosols, Tropospheric Ozone, and Long-lived Greenhouse Gases

Science.gov (United States)

Chen, Wei-Ting; Liao, Hong; Seinfeld, John H.

2007-01-01

Long-lived greenhouse gases (GHGs) are the most important driver of climate change over the next century. Aerosols and tropospheric ozone (O3) are expected to induce significant perturbations to the GHG-forced climate. To distinguish the equilibrium climate responses to changes in direct radiative forcing of anthropogenic aerosols, tropospheric ozone, and GHG between present day and year 2100, four 80-year equilibrium climates are simulated using a unified tropospheric chemistry-aerosol model within the Goddard Institute for Space Studies (GISS) general circulation model (GCM) 110. Concentrations of sulfate, nitrate, primary organic (POA) carbon, secondary organic (SOA) carbon, black carbon (BC) aerosols, and tropospheric ozone for present day and year 2100 are obtained a priori by coupled chemistry-aerosol GCM simulations, with emissions of aerosols, ozone, and precursors based on the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenario (SRES) A2. Changing anthropogenic aerosols, tropospheric ozone, and GHG from present day to year 2100 is predicted to perturb the global annual mean radiative forcing by +0.18 (considering aerosol direct effects only), +0.65, and +6.54 W m(sup -2) at the tropopause, and to induce an equilibrium global annual mean surface temperature change of +0.14, +0.32, and +5.31 K, respectively, with the largest temperature response occurring at northern high latitudes. Anthropogenic aerosols, through their direct effect, are predicted to alter the Hadley circulation owing to an increasing interhemispheric temperature gradient, leading to changes in tropical precipitation. When changes in both aerosols and tropospheric ozone are considered, the predicted patterns of change in global circulation and the hydrological cycle are similar to those induced by aerosols alone. GHG-induced climate changes, such as amplified warming over high latitudes, weakened Hadley circulation, and increasing precipitation over the

Land use changes and socio-economic development strongly deteriorate river ecosystem health in one of the largest basins in China.

Science.gov (United States)

Cheng, Xian; Chen, Liding; Sun, Ranhao; Kong, Peiru

2018-03-01

It is important to assess river ecosystem health in large-scale basins when considering the complex influence of anthropogenic activities on these ecosystems. This study investigated the river ecosystem health in the Haihe River Basin (HRB) by sampling 148 river sites during the pre- and post-rainy seasons in 2013. A model was established to assess the river ecosystem health based on water physicochemical, nutrient, and macroinvertebrate indices, and the health level was divided into "very poor," "poor," "fair," "good," and "excellent" according to the health score calculated from the assessment model. The assessment results demonstrated that the river ecosystem health of the HRB was "poor" overall, and no catchments were labeled "excellent." The percentages of catchments deemed to have "very poor," "poor," "fair," or "good" river ecosystem health were 12.88%, 40.91%, 40.15%, and 6.06%, respectively. From the pre- to the post-rainy season, the macroinvertebrate health levels improved from "poor" to "fair." The results of a redundancy analysis (RDA), path analysis of the structural equation model (SEM), and X-Y plots indicated that the land use types of forest land and grassland had positive relationships with river ecosystem health, whereas arable land, urban land, gross domestic product (GDP) per capita, and population density had negative relationships with river ecosystem health. The variance partitioning (VP) results showed that anthropogenic activities (including land use and socio-economy) together explained 30.9% of the variations in river ecosystem health in the pre-rainy season, and this value increased to 35.9% in the post-rainy season. Land use intensity was the first driver of river ecosystem health, and socio-economic activities was the second driver. Land use variables explained 20.5% and 25.7% of the variations in river ecosystem health in the pre- and post-rainy season samples, respectively, and socio-economic variables explained 12.3% and 17.2% of

Soil invertebrate communities in stressed European ecosystems

Energy Technology Data Exchange (ETDEWEB)

Butovsky, R.O. [All-Russian Research Institute for Nature Protection, Sadki-Znamenskoje (Russian Federation)

2003-07-01

Intensive landuse in Europe results in continual physical and chemical changes to land and soil. Soil invertebrates can be used for development of single- and multi-species test-systems for soil quality assessment under anthropogenous stress. The research was performed in 18 terrestrial ecosystems stressed by common anthropogenous impacts: recreation pressure, motorway or industrial pollution in Central Russia, Belgium and the Netherlands in 1983-2001. All three types of human stresses (recreation, motorway and industrial) induced similar changes of macroartropod and microarthropod communities. In stressed macroarthropod communities the decrease of abundance of non-specialized predators, chewing phytophagans, saprophagans and increase of abundance of rhyzophagans, sucking phytophagans and specialized predators was observed. All types of stresses increased or stabilized species diversity in macro- (in carabid beetles communities mainly increase of Harpalus and Amara species number, in weevils - Sitona species number etc.) and microarthropod (e.g. Mesostigmata mites species) communities. In stressed ecosystems sucking phytophagans have selective advantage as compared to chewing phytophagans, endoparasitoids as compared to ectoparasitoids, specialized predators as compared to non-specialized predators etc., meaning that the feeding strategy play an important regulatory role in the community. Saprophagans and phytophagans, consuming chemicals, e.g. heavy metals in large quantities, are in general highly sensitive groups. The most sensitive groups belonged to first and second order consumers. In putative trophic chains in roadside ecosystems, non-specialized zoophagans (predators) contained less copper and zinc, than specialized zoophagans and parasitoids. When compared to the peculiarities of distribution of pesticides (e.g. DDT) and radionuclides (Sr90 and Cs137) it happens that in terrestrial ecosystems heavy metals were primarily accumulated (1) in soil

Anthropogenic control on geomorphic process rates: can we slow down the erosion rates? (Geomorphology Outstanding Young Scientist Award & Penck Lecture)

Science.gov (United States)

Vanacker, V.

2012-04-01

The surface of the Earth is changing rapidly, largely in response to anthropogenic perturbation. Direct anthropogenic disturbance of natural environments may be much larger in many places than the (projected) indirect effects of climate change. There is now large evidence that humans have significantly altered geomorphic process rates, mainly through changes in vegetation composition, density and cover. While much attention has been given to the impact of vegetation degradation on geomorphic process rates, I suggest that the pathway of restoration is equally important to investigate. First, vegetation recovery after crop abandonment has a rapid and drastic impact on geomorphic process rates. Our data from degraded catchments in the tropical Andes show that erosion rates can be reduced by up to 100 times when increasing the protective vegetation cover. During vegetation restoration, the combined effects of the reduction in surface runoff, sediment production and hydrological connectivity are stronger than the individual effects together. Therefore, changes in erosion and sedimentation during restoration are not simply the reverse of those observed during degradation. Second, anthropogenic perturbation causes a profound but often temporary change in geomorphic process rates. Reconstruction of soil erosion rates in Spain shows us that modern erosion rates in well-vegetated areas are similar to long-term rates, despite evidence of strong pulses in historical erosion rates after vegetation clearance and agriculture. The soil vegetation system might be resilient to short pulses of accelerated erosion (and deposition), as there might exist a dynamic coupling between soil erosion and production also in degraded environments.

Analysis of climate and anthropogenic impacts on runoff in the Lower Pra River Basin of Ghana.

Science.gov (United States)

Awotwi, Alfred; Anornu, Geophrey Kwame; Quaye-Ballard, Jonathan; Annor, Thompson; Forkuo, Eric Kwabena

2017-12-01

The Lower Pra River Basin (LPRB), located in the forest zone of southern Ghana has experienced changes due to variability in precipitation and diverse anthropogenic activities. Therefore, to maintain the functions of the ecosystem for water resources management, planning and sustainable development, it is important to differentiate the impacts of precipitation variability and anthropogenic activities on stream flow changes. We investigated the variability in runoff and quantified the contributions of precipitation and anthropogenic activities on runoff at the LPRB. Analysis of the precipitation-runoff for the period 1970-2010 revealed breakpoints in 1986, 2000, 2004 and 2010 in the LPRB. The periods influenced by anthropogenic activities were categorized into three periods 1987-2000, 2001-2004 and 2005-2010, revealing a decrease in runoff during 1987-2000 and an increase in runoff during 2001-2004 and 2005-2010. Assessment of monthly, seasonal and annual runoff depicted a significant increasing trend in the runoff time series during the dry season. Generally, runoff increased at a rate of 9.98 × 10 7 m 3 yr -1 , with precipitation variability and human activities contributing 17.4% and 82.3% respectively. The dominant small scale alluvial gold mining activity significantly contributes to the net runoff variability in LPRB.

Time series monitoring of water quality and microalgal diversity in a tropical bay under intense anthropogenic interference (SW coast of the Bay of Bengal, India)

Digital Repository Service at National Institute of Oceanography (India)

Shaik, A.R.; Biswas, H.; Reddy, N.P.C.; Rao, V.S.; Bharathi, M.D.; Subbaiah, Ch.V.

In recent decades, material fluxes to coastal waters from various land based anthropogenic activities have signifi- cantly been enhanced around the globe which can considerably impact the coastal water quality and ecosystem health. Hence, there is a...

THE CONCENTRATION OF PHOTOSINTHESIS PIGMENTS IN THE ANTHROPOGENIC PLANT COMMUNITIES IN TOBOLSK TOWN

Directory of Open Access Journals (Sweden)

Еlena Ivanovna Popova

2016-10-01

Full Text Available Photosynthesis means a lot in the life of a plant body. For the normal photosynthesis process it is necessary to have certain external and internal conditions. The topic of the research is the study of photosynthesis pigments in anthropogenic plant communities. The aim of our work was to study the pigment composition plants of anthropogenic phytocenoses. Methods: we have used the spectrophotometric method to define the concentration of pigments. Results: the research has shown that the concentration of a – chlorophyll, b – chlorophyll and carotenoids changes depending on the site conditions. The maximal concentration of a and b chlorophyll is found on less polluted areas. High carotenoid concentration was found in stress anthropogenic conditions. On the one hand, this carotenoid concentration decreases the stress effect. On the other hand it fulfils the protection function, preventing the chlorophyll molecules and other organic substances from destruction. In the research you will find the species composition of vascular plants on the sites under research. Jaccard’s coefficient of community has been defined. Field of application of results: the data can be used to predict the dynamics of populations and communities of plants in the contaminated areas and monitor the status of natural ecosystems.

Bioassay for aquatic ecosystems review and classification; Rassegna dei principali test di ecotossicologia acquatica

Energy Technology Data Exchange (ETDEWEB)

Sanci, Antonella; Rosa, Silvia [ENEA, Centro Ricerche Casaccia, Rome (Italy). Dipt. Ambiente

1997-09-01

Bioassay play a crucial role in assessing the actual or potential impacts of anthropogenic agents on the natural environment. In this technical report, literature on bioassays for aquatic ecosystems has been reviewed and classified. Problems associated with the choice and application of bioassays are discussed.

Nutrient enrichment induces dormancy and decreases diversity of active bacteria in salt marsh sediments

Science.gov (United States)

Kearns, Patrick J.; Angell, John H.; Howard, Evan M.; Deegan, Linda A.; Stanley, Rachel H. R.; Bowen, Jennifer L.

2016-09-01

Microorganisms control key biogeochemical pathways, thus changes in microbial diversity, community structure and activity can affect ecosystem response to environmental drivers. Understanding factors that control the proportion of active microbes in the environment and how they vary when perturbed is critical to anticipating ecosystem response to global change. Increasing supplies of anthropogenic nitrogen to ecosystems globally makes it imperative that we understand how nutrient supply alters active microbial communities. Here we show that nitrogen additions to salt marshes cause a shift in the active microbial community despite no change in the total community. The active community shift causes the proportion of dormant microbial taxa to double, from 45 to 90%, and induces diversity loss in the active portion of the community. Our results suggest that perturbations to salt marshes can drastically alter active microbial communities, however these communities may remain resilient by protecting total diversity through increased dormancy.

Use of Pb and Sr isotopes as tracers of anthropogenic and natural inputs in rain waters and rivers of the Paris basin

International Nuclear Information System (INIS)

Roy, St.

1996-06-01

The isotopic composition of Pb and Sr, measured in the soluble phase of rain waters and rivers are used to determine and quantify the anthropogenic inputs and the weathering rates in the Seine basin. Atmospheric lead from rain waters is exclusively anthropogenic and is derived from gasoline and industrial emissions. These rain waters transfer lead, and certain other heavy metals, into the Seine, where the anthropogenic signal perturbs the natural geochemical cycle of these metals. This transfer to the river occurs principally in the city of Paris, in contrast, in the catchment area upstream of Paris, these elements are mainly trapped in soils, rather than transferred to the river. The anthropogenic inputs comprise three-quarters of the total transport of these metals by the Seine. In the river, lead transport is due to adsorption process occurring within the suspended load. Thus, soluble lead concentrations are linked to the river flow and the intensity of mechanical erosion. After correction for atmospheric and anthropogenic inputs, it is possible to estimate the silicate weathering rate for the Seine basin. This estimate is close to that obtained for large plain rivers, such as the Congo or Amazon, indicating that chemical erosion is linked to tectonic processes rather than climatic conditions. (author)

Substantial nitrous oxide emissions from intertidal sediments and groundwater in anthropogenically-impacted West Falmouth Harbor, Massachusetts

Science.gov (United States)

Moseman-Valtierra, Serena; Kroeger, Kevin D.; Crusius, John; Baldwin, Sandy; Green, Adrian; Brooks, Thomas W.; Pugh, E.

2015-01-01

Large N2O emissions were observed from intertidal sediments in a coastal estuary, West Falmouth Harbor, MA, USA. Average N2O emission rates from 41 chambers during summer 2008 were 10.7 mol N2O m(-2) h(-1)±4.43 μmol N2O m(-2) h(-1) (standard error). Emissions were highest from sediments within a known wastewater plume, where a maximum N2O emission rate was 155 μmol N2O m(-2) h(-1). Intertidal N2O fluxes were positively related to porewater ammonium concentrations at 10 and 25 cm depths. In groundwater from 7 shoreline wells, dissolved N2O ranged from 488% of saturation (56 nM N2O) to more than 13000% of saturation (1529 nM N2O) and was positively related to nitrate concentrations. Fresh and brackish porewater underlying 14 chambers was also supersaturated in N2O, ranging from 2980% to 13175% of saturation. These observations support a relationship between anthropogenic nutrient loading and N2O emissions in West Falmouth Harbor, with both groundwater sources and also local N2O production within nutrient-rich, intertidal sediments in the groundwater seepage face. N2O emissions from intertidal "hotspot" in this harbor, together with estimated surface water emissions, constituted 2.4% of the average overall rate of nitrogen export from the watershed to the estuary. This suggests that N2O emissions factors from coastal ecosystems may be underestimated. Since anthropogenic nutrient loading affects estuaries worldwide, quantification of N2O dynamics is warranted in other anthropogenically-impacted coastal ecosystems.

Substantial nitrous oxide emissions from intertidal sediments and groundwater in anthropogenically-impacted West Falmouth Harbor, Massachusetts.

Science.gov (United States)

Moseman-Valtierra, Serena; Kroeger, Kevin D; Crusius, John; Baldwin, Sandra; Green, Adrian; Brooks, T Wallace; Pugh, Emily

2015-01-01

Large N2O emissions were observed from intertidal sediments in a coastal estuary, West Falmouth Harbor, MA, USA. Average N2O emission rates from 41 chambers during summer 2008 were 10.7 mol N2O m(-2) h(-1)±4.43 μmol N2O m(-2) h(-1) (standard error). Emissions were highest from sediments within a known wastewater plume, where a maximum N2O emission rate was 155 μmol N2O m(-2) h(-1). Intertidal N2O fluxes were positively related to porewater ammonium concentrations at 10 and 25 cm depths. In groundwater from 7 shoreline wells, dissolved N2O ranged from 488% of saturation (56 nM N2O) to more than 13000% of saturation (1529 nM N2O) and was positively related to nitrate concentrations. Fresh and brackish porewater underlying 14 chambers was also supersaturated in N2O, ranging from 2980% to 13175% of saturation. These observations support a relationship between anthropogenic nutrient loading and N2O emissions in West Falmouth Harbor, with both groundwater sources and also local N2O production within nutrient-rich, intertidal sediments in the groundwater seepage face. N2O emissions from intertidal "hotspot" in this harbor, together with estimated surface water emissions, constituted 2.4% of the average overall rate of nitrogen export from the watershed to the estuary. This suggests that N2O emissions factors from coastal ecosystems may be underestimated. Since anthropogenic nutrient loading affects estuaries worldwide, quantification of N2O dynamics is warranted in other anthropogenically-impacted coastal ecosystems. Copyright © 2014 Elsevier Ltd. All rights reserved.

Sustainable utilization and conservation of plant biodiversity in montane ecosystems: the western Himalayas as a case study.

Science.gov (United States)

Khan, Shujaul Mulk; Page, Sue E; Ahmad, Habib; Harper, David M

2013-08-01

Conservation of the unique biodiversity of mountain ecosystems needs trans-disciplinary approaches to succeed in a crowded colloquial world. Geographers, conservationists, ecologists and social scientists have, in the past, had the same conservation goals but have tended to work independently. In this review, the need to integrate different conservation criteria and methodologies is discussed. New criteria are offered for prioritizing species and habitats for conservation in montane ecosystems that combine both ecological and social data. Ecological attributes of plant species, analysed through robust community statistical packages, provide unbiased classifications of species assemblages and environmental biodiversity gradients and yield importance value indices (IVIs). Surveys of local communities' utilization of the vegetation provides use values (UVs). This review suggests a new means of assessing anthropogenic pressure on plant biodiversity at both species and community levels by integrating IVI and UV data sets in a combined analysis. Mountain ecosystems are hot spots for plant conservation efforts because they hold a high overall plant diversity as communities replace each other along altitudinal and climatic gradients, including a high proportion of endemic species. This review contributes an enhanced understanding of (1) plant diversity in mountain ecosystems with special reference to the western Himalayas; (2) ethnobotanical and ecosystem service values of mountain vegetation within the context of anthropogenic impacts; and (3) local and regional plant conservation strategies and priorities.

Interfaces in aquatic ecosystems: Implications for transport and impact of anthropogenic compounds

Energy Technology Data Exchange (ETDEWEB)

Knulst, J.

1996-11-01

Mechanisms that govern transport, accumulation and toxicity of persistent pollutants at interfaces in aquatic ecosystems were the foci of this thesis. Specific attention was paid to humic substances, their occurrence, composition, and role in exchange processes across interfaces. It was concluded that: The composition of humic substances in aquatic surface microlayers is different from that of the subsurface water and terrestrial humic matter. Levels of dissolved organic carbon (DOC) in the aquatic surface microlayer reflect the DOC levels in the subsurface water. While the levels and enrichment of DOC in the microlayer generally show small variations, the levels and enrichment of particulate organic carbon (POC) vary to a great extent. Similarities exist between aquatic surface films, artificial semi-permeable and biological membranes regarding their structure and functioning. Acidification and liming of freshwater ecosystems affect DOC:POC ratio and humic composition of the surface film, thus influencing the partitioning of pollutants across aquatic interfaces. Properties of lake catchment areas extensively govern DOC:POC ratio both in the surface film and subsurface water. Increased UV-B irradiation changes the DOC:POC ratio in the surface film and thus affect transfer of matter across the interface. Transport of lipophilic, persistent organic pollutants across semi-permeable membranes is influenced by the solutes organic composition. 106 refs, 11 figs, 1 tab

El Niño and similar perturbation effects on the benthos of the Humboldt, California, and Benguela Current upwelling ecosystems

Science.gov (United States)

Arntz, W. E.; Gallardo, V. A.; Gutiérrez, D.; Isla, E.; Levin, L. A.; Mendo, J.; Neira, C.; Rowe, G. T.; Tarazona, J.; Wolff, M.

2006-03-01

taxa appear to alter their distribution on the continental margin. Other properties and reactions of the two Pacific EBC benthic ecosystems to El Niño seem to differ, too, as does the overall impact of major episodes (e.g., 1982/1983(1984) vs. 1997/1998). The relation of the "Benguela Niño" to ENSO seems unclear although many Pacific-Atlantic ocean and atmosphere teleconnections have been described. Warm, low-oxygen equatorial water seems to be transported into the upwelling area by similar mechanisms as in the Pacific, but most major impacts on the eukaryotic biota obviously come from other, independent perturbations such as an extreme eutrophication of the sediments ensuing in sulphidic eruptions and toxic algal blooms. Similarities and differences of the Humboldt and California Current benthic ecosystems are discussed with particular reference to ENSO impacts since 1972/73. Where there are data available, the authors include the Benguela Current ecosystem as another important, non-Pacific EBC, which also suffers from the effects of hypoxia.

Sensitivity of global ocean biogeochemical dynamics to ecosystem structure in a future climate

Science.gov (United States)

Manizza, Manfredi; Buitenhuis, Erik T.; Le Quéré, Corinne

2010-07-01

Terrestrial and oceanic ecosystem components of the Earth System models (ESMs) are key to predict the future behavior of the global carbon cycle. Ocean ecosystem models represent low complexity compared to terrestrial ecosystem models. In this study we use two ocean biogeochemical models based on the explicit representation of multiple planktonic functional types. We impose to the models the same future physical perturbation and compare the response of ecosystem dynamics, export production (EP) and ocean carbon uptake (OCU) to the same physical changes. Models comparison shows that: (1) EP changes directly translate into changes of OCU on decadal time scale, (2) the representation of ecosystem structure plays a pivotal role at linking OCU and EP, (3) OCU is highly sensitive to representation of ecosystem in the Equatorial Pacific and Southern Oceans.

Storm Effects on Net Ecosystem Productivity in Boreal Forests

Science.gov (United States)

Vestin, Patrik; Grelle, Achim; Lagergren, Fredrik; Hellström, Margareta; Langvall, Ola; Lindroth, Anders

2010-05-01

Regional carbon budgets are to some extent determined by disturbance in ecosystems. Disturbance is believed to be partly responsible for the large inter-annual variability of the terrestrial carbon balance. When neglecting anthropogenic disturbance, forest fires have been considered the most important kind of disturbance. However, also insect outbreaks and wind-throw may be major factors in regional carbon budgets. The effects of wind-throw on CO2 fluxes in boreal forests are not well known due to lack of data. Principally, the reduced carbon sequestration capacity, increased substrate availability and severe soil perturbation following wind-throw are expected to result in increased CO2 fluxes from the forest to the atmosphere. In January 2005, the storm Gudrun hit Sweden, which resulted in approx. 66 × 106m3storm-felled stem wood distributed over an area of approx. 272 000 ha. Eddy covariance flux measurements started at storm-felled areas in Asa and Toftaholm in central Sweden during summer 2005. Data from the first months suggests increased CO2 fluxes by a factor of 2.5-10, as compared to normal silviculture (clear-cutting). An important question is how long such enhanced CO2 fluxes persist. The BIOME-BGC model will be calibrated against measured CO2 fluxes from both sites for 2005 through 2009. Modeled data will be used to fill gaps in the data sets and annual carbon balances will be calculated. Data from Asa and Toftaholm will be presented at the conference.

Anthropogenic impact on amorphous silica pools in temperate soils

Directory of Open Access Journals (Sweden)

W. Clymans

2011-08-01

Full Text Available Human land use changes perturb biogeochemical silica (Si cycling in terrestrial ecosystems. This directly affects Si mobilisation and Si storage and influences Si export from the continents, although the magnitude of the impact is unknown. A major reason for our lack of understanding is that very little information exists on how land use affects amorphous silica (ASi storage in soils. We have quantified and compared total alkali-extracted (PSi_a and easily soluble (PSi_e Si pools at four sites along a gradient of anthropogenic disturbance in southern Sweden. Land use clearly affects ASi pools and their distribution. Total PSia and PSi_e for a continuous forested site at Siggaboda Nature Reserve (66 900 ± 22 800 kg SiO₂ ha⁻¹ and 952 ± 16 kg SiO₂ ha⁻¹ are significantly higher than disturbed land use types from the Råshult Culture Reserve including arable land (28 800 ± 7200 kg SiO₂ ha⁻¹ and 239 ± 91 kg SiO₂ ha⁻¹, pasture sites (27 300 ± 5980 kg SiO₂ ha⁻¹ and 370 ± 129 kg SiO₂ ha⁻¹ and grazed forest (23 600 ± 6370 kg SiO₂ ha⁻¹ and 346 ± 123 kg SiO₂ ha⁻¹. Vertical PSi_a and PSi_e profiles show significant (p < 0.05 variation among the sites. These differences in size and distribution are interpreted as the long-term effect of reduced ASi replenishment, as well as changes in ecosystem specific pedogenic processes and increased mobilisation of the PSi_a in disturbed soils. We have also made a first, though rough, estimate of the magnitude of change in temperate continental ASi pools due to human disturbance. Assuming that our data are representative, we estimate that total ASi storage in soils has declined by ca. 10 % since the onset of agricultural development (3000 BCE

Economic development and coastal ecosystem change in China

Science.gov (United States)

He, Qiang; Bertness, Mark D.; Bruno, John F.; Li, Bo; Chen, Guoqian; Coverdale, Tyler C.; Altieri, Andrew H.; Bai, Junhong; Sun, Tao; Pennings, Steven C.; Liu, Jianguo; Ehrlich, Paul R.; Cui, Baoshan

2014-01-01

Despite their value, coastal ecosystems are globally threatened by anthropogenic impacts, yet how these impacts are driven by economic development is not well understood. We compiled a multifaceted dataset to quantify coastal trends and examine the role of economic growth in China's coastal degradation since the 1950s. Although China's coastal population growth did not change following the 1978 economic reforms, its coastal economy increased by orders of magnitude. All 15 coastal human impacts examined increased over time, especially after the reforms. Econometric analysis revealed positive relationships between most impacts and GDP across temporal and spatial scales, often lacking dropping thresholds. These relationships generally held when influences of population growth were addressed by analyzing per capita impacts, and when population density was included as explanatory variables. Historical trends in physical and biotic indicators showed that China's coastal ecosystems changed little or slowly between the 1950s and 1978, but have degraded at accelerated rates since 1978. Thus economic growth has been the cause of accelerating human damage to China's coastal ecosystems. China's GDP per capita remains very low. Without strict conservation efforts, continuing economic growth will further degrade China's coastal ecosystems. PMID:25104138

Economic development and coastal ecosystem change in China.

Science.gov (United States)

He, Qiang; Bertness, Mark D; Bruno, John F; Li, Bo; Chen, Guoqian; Coverdale, Tyler C; Altieri, Andrew H; Bai, Junhong; Sun, Tao; Pennings, Steven C; Liu, Jianguo; Ehrlich, Paul R; Cui, Baoshan

2014-08-08

Despite their value, coastal ecosystems are globally threatened by anthropogenic impacts, yet how these impacts are driven by economic development is not well understood. We compiled a multifaceted dataset to quantify coastal trends and examine the role of economic growth in China's coastal degradation since the 1950s. Although China's coastal population growth did not change following the 1978 economic reforms, its coastal economy increased by orders of magnitude. All 15 coastal human impacts examined increased over time, especially after the reforms. Econometric analysis revealed positive relationships between most impacts and GDP across temporal and spatial scales, often lacking dropping thresholds. These relationships generally held when influences of population growth were addressed by analyzing per capita impacts, and when population density was included as explanatory variables. Historical trends in physical and biotic indicators showed that China's coastal ecosystems changed little or slowly between the 1950s and 1978, but have degraded at accelerated rates since 1978. Thus economic growth has been the cause of accelerating human damage to China's coastal ecosystems. China's GDP per capita remains very low. Without strict conservation efforts, continuing economic growth will further degrade China's coastal ecosystems.

Marine biodiversity-ecosystem functions under uncertain environmental futures.

Science.gov (United States)

Bulling, Mark T; Hicks, Natalie; Murray, Leigh; Paterson, David M; Raffaelli, Dave; White, Piran C L; Solan, Martin

2010-07-12

Anthropogenic activity is currently leading to dramatic transformations of ecosystems and losses of biodiversity. The recognition that these ecosystems provide services that are essential for human well-being has led to a major interest in the forms of the biodiversity-ecosystem functioning relationship. However, there is a lack of studies examining the impact of climate change on these relationships and it remains unclear how multiple climatic drivers may affect levels of ecosystem functioning. Here, we examine the roles of two important climate change variables, temperature and concentration of atmospheric carbon dioxide, on the relationship between invertebrate species richness and nutrient release in a model benthic estuarine system. We found a positive relationship between invertebrate species richness and the levels of release of NH(4)-N into the water column, but no effect of species richness on the release of PO(4)-P. Higher temperatures and greater concentrations of atmospheric carbon dioxide had a negative impact on nutrient release. Importantly, we found significant interactions between the climate variables, indicating that reliably predicting the effects of future climate change will not be straightforward as multiple drivers are unlikely to have purely additive effects, resulting in increased levels of uncertainty.

Marine biodiversity–ecosystem functions under uncertain environmental futures

Science.gov (United States)

Bulling, Mark T.; Hicks, Natalie; Murray, Leigh; Paterson, David M.; Raffaelli, Dave; White, Piran C. L.; Solan, Martin

2010-01-01

Anthropogenic activity is currently leading to dramatic transformations of ecosystems and losses of biodiversity. The recognition that these ecosystems provide services that are essential for human well-being has led to a major interest in the forms of the biodiversity–ecosystem functioning relationship. However, there is a lack of studies examining the impact of climate change on these relationships and it remains unclear how multiple climatic drivers may affect levels of ecosystem functioning. Here, we examine the roles of two important climate change variables, temperature and concentration of atmospheric carbon dioxide, on the relationship between invertebrate species richness and nutrient release in a model benthic estuarine system. We found a positive relationship between invertebrate species richness and the levels of release of NH4-N into the water column, but no effect of species richness on the release of PO4-P. Higher temperatures and greater concentrations of atmospheric carbon dioxide had a negative impact on nutrient release. Importantly, we found significant interactions between the climate variables, indicating that reliably predicting the effects of future climate change will not be straightforward as multiple drivers are unlikely to have purely additive effects, resulting in increased levels of uncertainty. PMID:20513718

Evaluation of anthropogenic urban soils. Final report; Bewertung anthropogener Stadtboeden. Abschlussbericht

Energy Technology Data Exchange (ETDEWEB)

Blume, H.P.; Schleuss, U. [eds.

1997-12-31

The research project `Evaluation of Anthropogenic Urban Soils` was subsidized by the German Federal Ministry of Education, Science, Research and Technology and adviced by the working group `Stadtboeden` of the German Society of Soil Science. It was realized as a cooperation between the universities of Berlin (TU), Halle-Wittenberg, Hohenheim, Kiel and Rostock and had three objectives: - to characterize soils developed from anthropogenic substratums (`urban soils`), - to figure out distribution patterns of such soils and - to verify whether urban soils could be evaluated according to their filtering and habitat function in the same way as soils developed from natural parent material. Evaluation methods based on easily obtainable field data had to be adapted to `urban soils` respectively developed anew. For that reason some typical soils of anthropogenic lithogenesis had to be examined between 1993 and 1996 both on their importance as habitats for plants and soil organisms and on their filtering, buffering and transforming capacities for organic and inorganic pollutants. Accordingly representative `urban soils` were gathered in the towns of Berlin, Eckernfoerde, Essen, Halle, Kiel, Rostock and Stuttgart; these soils had developed from technogenic substratums (brick and mortar debris, municipal waste, ashes, slag, sludge) and redeposited alkaline resp. acidic natural substratums (mud, coal mine and coking plant deposits). Some of the soils were influenced by ground water, and all soils developed from the same kind of parent material belonged to different stages of development. (orig./SR) [Deutsch] Ziele des vom BMBF gefoerderten und vom Arbeitskreis Stadtboeden der Deutschen Bodenkundlichen Gesellschaft beratenen Verbundprojektes `Bewertung anthropogener Stadtboeden` waren die Charakterisierung von Boeden anthropogener Substrate, die exemplarische Ermittlung des Verteilungsmusters derartiger Boeden und die Pruefung, inwieweit sie sich aehnlich den Boeden natuerlicher

Impacts of air pollution and climate change on forest ecosystems - emerging research needs

Science.gov (United States)

Elena Paoletti; Bytnerowicz; Chris Andersen; Algirdas Augustaitis; Marco Ferretti; Nancy Grulke; Madeleine S. Gunthardt-goerg; John Innes; Dale Johnson; Dave Karnosky; Jessada Luangjame; Rainer Matyssek; Steven McNulty; Gerhard Muller-Starck; Robert Musselman; Kevin Percy

2007-01-01

Outcomes from the 22nd meeting for Specialists in Air Pollution Effects on Forest Ecosystems "Forests under Anthropogenic Pressure – Effects of Air Pollution, Climate Change and Urban Development", September 10–16, 2006, Riverside, CA, are summarized. Tropospheric or ground-level ozone (O3) is still the phytotoxic...

Impacts to ecosystem services from aquatic acidification: using FEGS-CS to understand the impacts of air pollution

Science.gov (United States)

Increases in anthropogenic emissions of sulfur (S) and nitrogen (N) have resulted in increases in the associated atmospheric deposition of acidic compounds. In sensitive watersheds, this deposition has initiated a cascade of negative environmental effects on aquatic ecosystems, ...

Ecosystem evolution of Lake Gusinoe (Transbaikal region, Russia)

Energy Technology Data Exchange (ETDEWEB)

Pisarsky, B.L.; Hardina, A.M.; Naganawa, H. [Russian Academy of Science, Irkutsk (Russian Federation). Siberian Division

2005-12-01

Lake Gusinoe is situated on a basin originating from Paleozoic and Mesozoic deposits. The recorded history of the lake's ecosystem evolution is no more than 300 years. The present lake drainage basin was formed mainly in the Cenozoic era, but during the past century, major anthropogenic impacts on the lake have occurred. The human-influenced evolution of the ecosystem began in the 1940s with the development of opencut coal mining nearby the lake. Population increase and the building of the Gusinoozersk State Regional Power Plant, the TransMongolian Railroad and an associated station, and military installations were the major sources of anthropogenic impacts. Since the early 1950s about five species of fish have been introduced into Lake Gusinoe or have invaded the lake, and at least six of the native species have disappeared or are in danger of extinction. From our recent investigations, the present environment of the Lake Gusinoe Basin (Gusinoozersk Basin) is divided into four zones hydro-geochemically: (1) ultrafreshwater, (2) freshwater, (3) mineralized water, and (4) hyposaline and saltwater. Some additional data on changes of the chemical components of the drainage basin waters, as well as on the transition of zooplankton and zoobenthic fauna, are presented in consideration of the risk of industrial development, and the perspectives are discussed.

Selection of anthropogenic features and vegetation characteristics by nesting Common Ravens in the sagebrush ecosystem

Science.gov (United States)

Howe, Kristy B.; Coates, Peter S.; Delehanty, David J.

2014-01-01

Common Raven (Corvus corax) numbers and distribution are increasing throughout the sagebrush steppe, influencing avian communities in complex ways. Anthropogenic structures are thought to increase raven populations by providing food and nesting subsidies, which is cause for concern because ravens are important nest predators of sensitive species, including Greater Sage-Grouse (Centrocercus urophasianus). During 2007–2009, we located raven nests in southeastern Idaho and conducted a resource selection analysis. We measured variables at multiple spatial scales for 72 unique nest locations, including landscape-level vegetation characteristics and anthropogenic structures. Using generalized linear mixed models and an information-theoretic approach, we found a 31% decrease in the odds of nesting by ravens for every 1 km increase in distance away from a transmission line. Furthermore, a 100-m increase in distance away from the edge of two different land cover types decreased the odds of nesting by 20%, and an increase in the amount of edge by 1 km within an area of 102.1 ha centered on the nest increased the odds of nesting by 49%. A post hoc analysis revealed that ravens were most likely to nest near edges of adjoining big sagebrush (Artemisia tridentata) and land cover types that were associated with direct human disturbance or fire. These findings contribute to our understanding of raven expansion into rural environments and could be used to make better-informed conservation decisions, especially in the face of increasing renewable energy development.

Nighttime dissolution in a temperate coastal ocean ecosystem increases under acidification.

Science.gov (United States)

Kwiatkowski, Lester; Gaylord, Brian; Hill, Tessa; Hosfelt, Jessica; Kroeker, Kristy J; Nebuchina, Yana; Ninokawa, Aaron; Russell, Ann D; Rivest, Emily B; Sesboüé, Marine; Caldeira, Ken

2016-03-18

Anthropogenic emissions of carbon dioxide (CO2) are causing ocean acidification, lowering seawater aragonite (CaCO3) saturation state (Ω arag), with potentially substantial impacts on marine ecosystems over the 21(st) Century. Calcifying organisms have exhibited reduced calcification under lower saturation state conditions in aquaria. However, the in situ sensitivity of calcifying ecosystems to future ocean acidification remains unknown. Here we assess the community level sensitivity of calcification to local CO2-induced acidification caused by natural respiration in an unperturbed, biodiverse, temperate intertidal ecosystem. We find that on hourly timescales nighttime community calcification is strongly influenced by Ω arag, with greater net calcium carbonate dissolution under more acidic conditions. Daytime calcification however, is not detectably affected by Ω arag. If the short-term sensitivity of community calcification to Ω arag is representative of the long-term sensitivity to ocean acidification, nighttime dissolution in these intertidal ecosystems could more than double by 2050, with significant ecological and economic consequences.

Integrating community assembly and biodiversity to better understand ecosystem function: the Community Assembly and the Functioning of Ecosystems (CAFE) approach.

Science.gov (United States)

Bannar-Martin, Katherine H; Kremer, Colin T; Ernest, S K Morgan; Leibold, Mathew A; Auge, Harald; Chase, Jonathan; Declerck, Steven A J; Eisenhauer, Nico; Harpole, Stanley; Hillebrand, Helmut; Isbell, Forest; Koffel, Thomas; Larsen, Stefano; Narwani, Anita; Petermann, Jana S; Roscher, Christiane; Cabral, Juliano Sarmento; Supp, Sarah R

2018-02-01

The research of a generation of ecologists was catalysed by the recognition that the number and identity of species in communities influences the functioning of ecosystems. The relationship between biodiversity and ecosystem functioning (BEF) is most often examined by controlling species richness and randomising community composition. In natural systems, biodiversity changes are often part of a bigger community assembly dynamic. Therefore, focusing on community assembly and the functioning of ecosystems (CAFE), by integrating both species richness and composition through species gains, losses and changes in abundance, will better reveal how community changes affect ecosystem function. We synthesise the BEF and CAFE perspectives using an ecological application of the Price equation, which partitions the contributions of richness and composition to function. Using empirical examples, we show how the CAFE approach reveals important contributions of composition to function. These examples show how changes in species richness and composition driven by environmental perturbations can work in concert or antagonistically to influence ecosystem function. Considering how communities change in an integrative fashion, rather than focusing on one axis of community structure at a time, will improve our ability to anticipate and predict changes in ecosystem function. © 2017 The Authors. Ecology Letters published by CNRS and John Wiley & Sons Ltd.

Consistent nutrient storage and supply mediated by diverse fish communities in coral reef ecosystems.

Science.gov (United States)

Allgeier, Jacob E; Layman, Craig A; Mumby, Peter J; Rosemond, Amy D

2014-08-01

Corals thrive in low nutrient environments and the conservation of these globally imperiled ecosystems is largely dependent on mitigating the effects of anthropogenic nutrient enrichment. However, to better understand the implications of anthropogenic nutrients requires a heightened understanding of baseline nutrient dynamics within these ecosystems. Here, we provide a novel perspective on coral reef nutrient dynamics by examining the role of fish communities in the supply and storage of nitrogen (N) and phosphorus (P). We quantified fish-mediated nutrient storage and supply for 144 species and modeled these data onto 172 fish communities (71 729 individual fish), in four types of coral reefs, as well as seagrass and mangrove ecosystems, throughout the Northern Antilles. Fish communities supplied and stored large quantities of nutrients, with rates varying among ecosystem types. The size structure and diversity of the fish communities best predicted N and P supply and storage and N : P supply, suggesting that alterations to fish communities (e.g., overfishing) will have important implications for nutrient dynamics in these systems. The stoichiometric ratio (N : P) for storage in fish mass (~8 : 1) and supply (~20 : 1) was notably consistent across the four coral reef types (but not seagrass or mangrove ecosystems). Published nutrient enrichment studies on corals show that deviations from this N : P supply ratio may be associated with poor coral fitness, providing qualitative support for the hypothesis that corals and their symbionts may be adapted to specific ratios of nutrient supply. Consumer nutrient stoichiometry provides a baseline from which to better understand nutrient dynamics in coral reef and other coastal ecosystems, information that is greatly needed if we are to implement more effective measures to ensure the future health of the world's oceans. © 2014 John Wiley & Sons Ltd.

Biodiversity increases the resistance of ecosystem productivity to climate extremes.

Science.gov (United States)

Isbell, Forest; Craven, Dylan; Connolly, John; Loreau, Michel; Schmid, Bernhard; Beierkuhnlein, Carl; Bezemer, T Martijn; Bonin, Catherine; Bruelheide, Helge; de Luca, Enrica; Ebeling, Anne; Griffin, John N; Guo, Qinfeng; Hautier, Yann; Hector, Andy; Jentsch, Anke; Kreyling, Jürgen; Lanta, Vojtěch; Manning, Pete; Meyer, Sebastian T; Mori, Akira S; Naeem, Shahid; Niklaus, Pascal A; Polley, H Wayne; Reich, Peter B; Roscher, Christiane; Seabloom, Eric W; Smith, Melinda D; Thakur, Madhav P; Tilman, David; Tracy, Benjamin F; van der Putten, Wim H; van Ruijven, Jasper; Weigelt, Alexandra; Weisser, Wolfgang W; Wilsey, Brian; Eisenhauer, Nico

2015-10-22

It remains unclear whether biodiversity buffers ecosystems against climate extremes, which are becoming increasingly frequent worldwide. Early results suggested that the ecosystem productivity of diverse grassland plant communities was more resistant, changing less during drought, and more resilient, recovering more quickly after drought, than that of depauperate communities. However, subsequent experimental tests produced mixed results. Here we use data from 46 experiments that manipulated grassland plant diversity to test whether biodiversity provides resistance during and resilience after climate events. We show that biodiversity increased ecosystem resistance for a broad range of climate events, including wet or dry, moderate or extreme, and brief or prolonged events. Across all studies and climate events, the productivity of low-diversity communities with one or two species changed by approximately 50% during climate events, whereas that of high-diversity communities with 16-32 species was more resistant, changing by only approximately 25%. By a year after each climate event, ecosystem productivity had often fully recovered, or overshot, normal levels of productivity in both high- and low-diversity communities, leading to no detectable dependence of ecosystem resilience on biodiversity. Our results suggest that biodiversity mainly stabilizes ecosystem productivity, and productivity-dependent ecosystem services, by increasing resistance to climate events. Anthropogenic environmental changes that drive biodiversity loss thus seem likely to decrease ecosystem stability, and restoration of biodiversity to increase it, mainly by changing the resistance of ecosystem productivity to climate events.

Trends and drivers of fire activity vary across California aridland ecosystems

Science.gov (United States)

Syphard, Alexandra D.; Keeley, Jon E.; Abatzoglou, John T.

2017-01-01

Fire activity has increased in western US aridland ecosystems due to increased human-caused ignitions and the expansion of flammable exotic grasses. Because many desert plants are not adapted to fire, increased fire activity may have long-lasting ecological impacts on native vegetation and the wildlife that depend on it. Given the heterogeneity across aridland ecosystems, it is important to understand how trends and drivers of fire vary, so management can be customized accordingly. We examined historical trends and quantified the relative importance of and interactions among multiple drivers of fire patterns across five aridland ecoregions in southeastern California from 1970 to 2010. Fire frequency increased across all ecoregions for the first couple decades, and declined or plateaued since the 1990s; but area burned continued to increase in some regions. The relative importance of anthropogenic and biophysical drivers varied across ecoregions, with both direct and indirect influences on fire. Anthropogenic variables were equally important as biophysical variables, but some contributed indirectly, presumably via their influence on annual grass distribution and abundance. Grass burned disproportionately more than other cover types, suggesting that addressing exotics may be the key to fire management and conservation in much of the area.

Radioactive cesium in a boreal forest ecosystem. Ecological concepts in radioecology

International Nuclear Information System (INIS)

Palo, R.T.

1991-01-01

Radioecology is traditionally viewing ecosystems as process functional units while modern ecology focus more on interactions among populations and communities. Taken separately they may lead to incomplete conclusion about radionuclide behaviour and give a too simplified view of the system. I adopt an hierarchical approach by focusing on the forest ecosystem, populations and individuals. I present a theoretical framework commonly used in analysis of herbivore- plant interactions and give an example on how individual behaviour perturbate to higher levels of ecological organizations. (au) (20 refs.)

Comparative study of potential transfer of natural and anthropogenic cadmium to plankton communities in the North-West African upwelling

Energy Technology Data Exchange (ETDEWEB)

Auger, P.A., E-mail: pierreamael.auger@gmail.com [Laboratoire de Physique des Océans (LPO), UMR-CNRS 6523/IFREMER/IRD/UBO, BP70, 29280 Plouzané (France); Machu, E.; Gorgues, T.; Grima, N. [Laboratoire de Physique des Océans (LPO), UMR-CNRS 6523/IFREMER/IRD/UBO, BP70, 29280 Plouzané (France); Waeles, M. [Université de Bretagne Occidentale (UBO), Laboratoire de l' Environnement Marin (LEMAR), UMR-CNRS 6539/IRD/UBO, place N. Copernic, 29280 Plouzané (France)

2015-02-01

A Lagrangian approach based on a physical–biogeochemical modeling was used to compare the potential transfer of cadmium (Cd) from natural and anthropogenic sources to plankton communities (Cd-uptake) in the North-West African upwelling. In this region, coastal upwelling was estimated to be the main natural source of Cd while the most significant anthropogenic source for marine ecosystem is provided by phosphate industry. In our model experiment, Cd-uptake (natural or anthropogenic) in the North-West African upwelling is the result of an interplay between the Cd dispersion (by advection processes) and the simulated biological productivity. In the Moroccan waters, advection processes limit the residence time of water masses resulting in a low natural Cd-uptake by plankton communities while anthropogenic Cd-uptake is high. As expected, the situation is reversed in the Senegalo-Mauritanian upwelling where natural Cd-uptake is higher than anthropogenic Cd-uptake. Based upon an estimate of Cd sources, our modeling study shows, unexpectedly, that the anthropogenic signal of potential Cd-bioaccumulation in the Moroccan upwelling is of the same order of magnitude as the natural signal mainly present in the Senegalo-Mauritanian upwelling region. A comparison with observed Cd levels in mollusk and fishes, which shows overall agreement with our simulations, is confirming our estimates. - Highlights: • We model the physical–biogeochemical dynamics in the North-West African upwelling. • We model the transport of cadmium from natural and anthropogenic sources. • We derive proxies of potential cadmium absorption and bioaccumulation in the plankton food chain. • The anthropogenic signal off Morocco at least equals the natural upwelling signal off Mauritania. • We compare our results with observed cadmium levels in mollusks and fishes.

Comparative study of potential transfer of natural and anthropogenic cadmium to plankton communities in the North-West African upwelling

International Nuclear Information System (INIS)

Auger, P.A.; Machu, E.; Gorgues, T.; Grima, N.; Waeles, M.

2015-01-01

A Lagrangian approach based on a physical–biogeochemical modeling was used to compare the potential transfer of cadmium (Cd) from natural and anthropogenic sources to plankton communities (Cd-uptake) in the North-West African upwelling. In this region, coastal upwelling was estimated to be the main natural source of Cd while the most significant anthropogenic source for marine ecosystem is provided by phosphate industry. In our model experiment, Cd-uptake (natural or anthropogenic) in the North-West African upwelling is the result of an interplay between the Cd dispersion (by advection processes) and the simulated biological productivity. In the Moroccan waters, advection processes limit the residence time of water masses resulting in a low natural Cd-uptake by plankton communities while anthropogenic Cd-uptake is high. As expected, the situation is reversed in the Senegalo-Mauritanian upwelling where natural Cd-uptake is higher than anthropogenic Cd-uptake. Based upon an estimate of Cd sources, our modeling study shows, unexpectedly, that the anthropogenic signal of potential Cd-bioaccumulation in the Moroccan upwelling is of the same order of magnitude as the natural signal mainly present in the Senegalo-Mauritanian upwelling region. A comparison with observed Cd levels in mollusk and fishes, which shows overall agreement with our simulations, is confirming our estimates. - Highlights: • We model the physical–biogeochemical dynamics in the North-West African upwelling. • We model the transport of cadmium from natural and anthropogenic sources. • We derive proxies of potential cadmium absorption and bioaccumulation in the plankton food chain. • The anthropogenic signal off Morocco at least equals the natural upwelling signal off Mauritania. • We compare our results with observed cadmium levels in mollusks and fishes

Interactions between Cryptosporidium parvum and the Intestinal Ecosystem

KAUST Repository

Douvropoulou, Olga

2017-04-01

Cryptosporidium parvum is an apicomplexan protozoan parasite commonly causing diarrhea, particularly in infants in developing countries. The research challenges faced in the development of therapies against Cryptosporidium slow down the process of drug discovery. However, advancement of knowledge towards the interactions of the intestinal ecosystem and the parasite could provide alternative approaches to tackle the disease. Under this perspective, the primary focus of this work was to study interactions between Cryptosporidium parvum and the intestinal ecosystem in a mouse model. Mice were treated with antibiotics with different activity spectra and the resulted perturbation of the native gut microbiota was identified by microbiome studies. In particular, 16S amplicon sequencing and Whole Genome Sequencing (WGS) were used to determine the bacterial composition and the genetic repertoire of the fecal microbial communities in the mouse gut. Following alteration of the microbial communities of mice by application of antibiotic treatment, Cryptosporidium parasites were propagated in mice with perturbed microbiota and the severity of the infection was quantified. This approach enabled the prediction of the functional capacity of the microbial communities in the mouse gut and led to the identification of bacterial taxa that positively or negatively correlate in abundance with Cryptosporidium proliferation.

The influence of watershed perturbation on mercury loading in the littoral biofilms: preliminary results

Energy Technology Data Exchange (ETDEWEB)

Desrosiers, M.; Planas, D. [Quebec Univ., GEOTOP, Montreal. PQ, (Canada); Mucci, A.; Guignard, C. [McGill Univ., Dept. of Earth and Planetary Sciences, Montreal, PQ (Canada)

1999-05-01

Methylmercury accumulation in littoral biofilms associated with anthropogenic watershed perturbation (harvesting) was evaluated and compared to natural perturbation (forest fires) and undisturbed lakes. Communities in littoral zones are the main food resources for many fish species. In the littoral zone, biofilms are at the base of the food chain and may prove to be an important source of mercury to fish. A total of 15 lakes were studied, equally distributed among the three types of disturbances. Methylmercury analysis was done in biofilms grown on Teflon substrates suspended in the littoral zone. The methylmercury was extracted with 25 per cent KOH in methanol and its concentration measured by cold-vapour atomic fluorescence following ethylation and gas chromatographic separation. Preliminary results show that methylmercury concentrations on the substrates are correlated with the biofilm algal biomass. In turn, the algal biomass is correlated to the degree of watershed perturbation associated with increased nutrient input, i.e. an increase in biofilm biomass may lead to greater availability of methylmercury for organisms that feed on the algae. Based on these observations, it was suggested that algae may play a significant role in the bioaccumulation of methylmercury by higher trophic organisms. Watershed perturbations appear to increase the bioavailability of methylmercury for aquatic organisms by way of increased production and consumption of littoral biofilms. 11 refs.

Ultra-High Foraging Rates of Harbor Porpoises Make Them Vulnerable to Anthropogenic Disturbance.

Science.gov (United States)

Wisniewska, Danuta Maria; Johnson, Mark; Teilmann, Jonas; Rojano-Doñate, Laia; Shearer, Jeanne; Sveegaard, Signe; Miller, Lee A; Siebert, Ursula; Madsen, Peter Teglberg

2016-06-06

The question of how individuals acquire and allocate resources to maximize fitness is central in evolutionary ecology. Basic information on prey selection, search effort, and capture rates are critical for understanding a predator's role in its ecosystem and for predicting its response to natural and anthropogenic disturbance. Yet, for most marine species, foraging interactions cannot be observed directly. The high costs of thermoregulation in water require that small marine mammals have elevated energy intakes compared to similar-sized terrestrial mammals [1]. The combination of high food requirements and their position at the apex of most marine food webs may make small marine mammals particularly vulnerable to changes within the ecosystem [2-4], but the lack of detailed information about their foraging behavior often precludes an informed conservation effort. Here, we use high-resolution movement and prey echo recording tags on five wild harbor porpoises to examine foraging interactions in one of the most metabolically challenged cetacean species. We report that porpoises forage nearly continuously day and night, attempting to capture up to 550 small (3-10 cm) fish prey per hour with a remarkable prey capture success rate of >90%. Porpoises therefore target fish that are smaller than those of commercial interest, but must forage almost continually to meet their metabolic demands with such small prey, leaving little margin for compensation. Thus, for these "aquatic shrews," even a moderate level of anthropogenic disturbance in the busy shallow waters they share with humans may have severe fitness consequences at individual and population levels. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of belowground litter addition, increased precipitation and clipping on soil carbon and nitrogen mineralization in a temperate steppe

OpenAIRE

Ma, L.; Guo, C.; Xin, X.; Yuan, S.; Wang, R.

2013-01-01

Soil carbon (C) and nitrogen (N) cycling are sensitive to changes in environmental factors and play critical roles in the responses of terrestrial ecosystems to natural and anthropogenic perturbations. This study was conducted to quantify the effects of belowground particulate litter (BPL) addition, increased precipitation and their interactions on soil C and N mineralization in two adjacent sites where belowground photosynthate allocation was manipulated through vegetation ...

Anthropogenics: human influence on global and genetic homogenization of parasite populations.

Science.gov (United States)

Zarlenga, Dante S; Hoberg, Eric; Rosenthal, Benjamin; Mattiucci, Simonetta; Nascetti, Giuseppe

2014-12-01

The distribution, abundance, and diversity of life on Earth have been greatly shaped by human activities. This includes the geographic expansion of parasites; however, measuring the extent to which humans have influenced the dissemination and population structure of parasites has been challenging. In-depth comparisons among parasite populations extending to landscape-level processes affecting disease emergence have remained elusive. New research methods have enhanced our capacity to discern human impact, where the tools of population genetics and molecular epidemiology have begun to shed light on our historical and ongoing influence. Only since the 1990s have parasitologists coupled morphological diagnosis, long considered the basis of surveillance and biodiversity studies, with state-of-the-art tools enabling variation to be examined among, and within, parasite populations. Prior to this time, populations were characterized only by phenotypic attributes such as virulence, infectivity, host range, and geographical location. The advent of genetic/molecular methodologies (multilocus allozyme electrophoresis, polymerase chain reaction-DNA [PCR-DNA] fragments analysis, DNA sequencing, DNA microsatellites, single nucleotide polymorphisms, etc.) have transformed our abilities to reveal variation among, and within, populations at local, regional, landscape, and global scales, and thereby enhanced our understanding of the biosphere. Numerous factors can affect population structure among parasites, e.g., evolutionary and ecological history, mode of reproduction and transmission, host dispersal, and life-cycle complexity. Although such influences can vary considerably among parasite taxa, anthropogenic factors are demonstrably perturbing parasite fauna. Minimal genetic structure among many geographically distinct (isolated) populations is a hallmark of human activity, hastened by geographic introductions, environmental perturbation, and global warming. Accelerating

Benthic communities under anthropogenic pressure show resilience across the Quaternary.

Science.gov (United States)

Martinelli, Julieta C; Soto, Luis P; González, Jorge; Rivadeneira, Marcelo M

2017-09-01

The Southeast Pacific is characterized by rich upwelling systems that have sustained and been impacted by human groups for at least 12 ka. Recent fishing and aquaculture practices have put a strain on productive coastal ecosystems from Tongoy Bay, in north-central Chile. We use a temporal baseline to determine whether potential changes to community structure and composition over time are due to anthropogenic factors, natural climatic variations or both. We compiled a database ( n  = 33 194) with mollusc species abundances from the Mid-Pleistocene, Late Pleistocene, Holocene, dead shell assemblages and live-sampled communities. Species richness was not significantly different, neither were diversity and evenness indices nor rank abundance distributions. There is, however, an increase in relative abundance for the cultured scallop Argopecten , while the previously dominant clam Mulinia is locally very rare. Results suggest that impacts from both natural and anthropogenic stressors need to be better understood if benthic resources are to be preserved. These findings provide the first Pleistocene temporal baseline for the south Pacific that shows that this highly productive system has had the ability to recover from past alterations, suggesting that if monitoring and management practices continue to be implemented, moderately exploited communities from today have hopes for recovery.

Benthic communities under anthropogenic pressure show resilience across the Quaternary

Science.gov (United States)

Martinelli, Julieta C.; Soto, Luis P.; González, Jorge; Rivadeneira, Marcelo M.

2017-09-01

The Southeast Pacific is characterized by rich upwelling systems that have sustained and been impacted by human groups for at least 12 ka. Recent fishing and aquaculture practices have put a strain on productive coastal ecosystems from Tongoy Bay, in north-central Chile. We use a temporal baseline to determine whether potential changes to community structure and composition over time are due to anthropogenic factors, natural climatic variations or both. We compiled a database (n = 33 194) with mollusc species abundances from the Mid-Pleistocene, Late Pleistocene, Holocene, dead shell assemblages and live-sampled communities. Species richness was not significantly different, neither were diversity and evenness indices nor rank abundance distributions. There is, however, an increase in relative abundance for the cultured scallop Argopecten, while the previously dominant clam Mulinia is locally very rare. Results suggest that impacts from both natural and anthropogenic stressors need to be better understood if benthic resources are to be preserved. These findings provide the first Pleistocene temporal baseline for the south Pacific that shows that this highly productive system has had the ability to recover from past alterations, suggesting that if monitoring and management practices continue to be implemented, moderately exploited communities from today have hopes for recovery.

Mapping 1995 global anthropogenic emissions of mercury

Science.gov (United States)

Pacyna, Jozef M.; Pacyna, Elisabeth G.; Steenhuisen, Frits; Wilson, Simon

This paper presents maps of anthropogenic Hg emissions worldwide within a 1°×1° latitude/longitude grid system in 1995. As such, the paper is designed for modelers simulating the Hg transport within air masses and Hg deposition to aquatic and terrestrial ecosystems. Maps of total Hg emissions and its three main chemical species: elemental gaseous Hg, divalent gaseous Hg, and particle-associated Hg are presented. The main emissions occur in southeast Asia (particularly in China), South Africa, Central and Eastern Europe, and the Eastern United States. These are the regions where coal combustion is the main source of electricity and heat production. Waste incineration adds to these emissions in the Eastern United States. Emissions of total Hg and its three species are quite similar in terms of their (global) spatial distributions. They reflect the worldwide distribution of coal consumption in large power plants, industrial burners, and small combustion units, such as residential and commercial furnaces.

Ecosystem vulnerability to climate change in the southeastern United States

Science.gov (United States)

Cartwright, Jennifer M.; Costanza, Jennifer

2016-08-11

Two recent investigations of climate-change vulnerability for 19 terrestrial, aquatic, riparian, and coastal ecosystems of the southeastern United States have identified a number of important considerations, including potential for changes in hydrology, disturbance regimes, and interspecies interactions. Complementary approaches using geospatial analysis and literature synthesis integrated information on ecosystem biogeography and biodiversity, climate projections, vegetation dynamics, soil and water characteristics, anthropogenic threats, conservation status, sea-level rise, and coastal flooding impacts. Across a diverse set of ecosystems—ranging in size from dozens of square meters to thousands of square kilometers—quantitative and qualitative assessments identified types of climate-change exposure, evaluated sensitivity, and explored potential adaptive capacity. These analyses highlighted key gaps in scientific understanding and suggested priorities for future research. Together, these studies help create a foundation for ecosystem-level analysis of climate-change vulnerability to support effective biodiversity conservation in the southeastern United States.

Biological effects of anthropogenic chemical stress: Tools for the assessment of ecosystem health (BEAST)

DEFF Research Database (Denmark)

Lehtonen, Kari K.; Sundelin, Brita; Lang, Thomas

: Tools for the Assessment of Ecosystem Health, 2009-2011), which is part of the Baltic Sea BONUS+ Programme funded jointly by national funding agencies and FP7 ERA-NET+ of the European Commission. The BEAST project consists of three workpackages (WP) with the following main tasks: WP1- Field studies...... and experiments in selected sub-regions of the Baltic Sea, WP2 - Application and validation of methods in monitoring and assessment in the Baltic Sea, and WP3 - Developing tools for ecosystem health assessment in the Baltic Sea. BEAST research activities are focused in the sub-regions of Gulf of Bothnia, Gulf...... of Finland, Gulf of Riga, Gulf of Gdansk and the Belt Sea, most of which are characterised by scarce data on biological effects of hazardous substances. The data acquired will be combined with previous data (e.g. national monitoring activities, case studies, EU BEEP project) to reach the goals of WP2 and WP3...

Distinguishing between anthropogenic and climatic impacts on lake size: a modeling approach using data from Ebinur Lake in arid northwest China

Directory of Open Access Journals (Sweden)

Long Ma

2014-03-01

Full Text Available Evaluation of anthropogenic and climatic impacts on lake size variation is important for maintaining ecosystem integrity and sustaining societal development. We assumed that climate and human activity are the only drivers of lake-size variation and are independent of each other. We then evaluated anthropogenic and climatic effects on hydrological processes, using a multivariate linear model. Macro-economic data were used to describe the anthropogenic impact on lake surface area in our approach. Ebinur Lake is a shallow, closed, saline lake in arid northwest China; it has shrunk at a rapid rate over the past half century. Using our new method, we explored temporal trends of anthropogenic and climatic impacts on the lake over the past 50 years. Assessment indices indicate that the model represents observed data quite well. Compared with the reference period of 1955-1960, impacts of climate change across the catchment were generally positive with respect to lake area, except for the period from 1961 to 1970. Human activity was responsible for a reduction in lake surface area of 286.8 km2 over the last 50 years. Our approach, which uses economic variables to describe the anthropogenic impact on lake surface area, enables us to explain the lake responses to climate change and human activities quantitatively.

Trade-offs across space, time, and ecosystem services

Science.gov (United States)

Rodriguez, J.P.; Beard, T.D.; Bennett, E.M.; Cumming, Graeme S.; Cork, S.J.; Agard, J.; Dobson, A.P.; Peterson, G.D.

2006-01-01

Ecosystem service (ES) trade-offs arise from management choices made by humans, which can change the type, magnitude, and relative mix of services provided by ecosystems. Trade-offs occur when the provision of one ES is reduced as a consequence of increased use of another ES. In some cases, a trade-off may be an explicit choice; but in others, trade-offs arise without premeditation or even awareness that they are taking place. Trade-offs in ES can be classified along three axes: spatial scale, temporal scale, and reversibility. Spatial scale refers to whether the effects of the trade-off are felt locally or at a distant location. Temporal scale refers to whether the effects take place relatively rapidly or slowly. Reversibility expresses the likelihood that the perturbed ES may return to its original state if the perturbation ceases. Across all four Millennium Ecosystem Assessment scenarios and selected case study examples, trade-off decisions show a preference for provisioning, regulating, or cultural services (in that order). Supporting services are more likely to be "taken for granted." Cultural ES are almost entirely unquantified in scenario modeling; therefore, the calculated model results do not fully capture losses of these services that occur in the scenarios. The quantitative scenario models primarily capture the services that are perceived by society as more important - provisioning and regulating ecosystem services - and thus do not fully capture trade-offs of cultural and supporting services. Successful management policies will be those that incorporate lessons learned from prior decisions into future management actions. Managers should complement their actions with monitoring programs that, in addition to monitoring the short-term provisions of services, also monitor the long-term evolution of slowly changing variables. Policies can then be developed to take into account ES trade-offs at multiple spatial and temporal scales. Successful strategies will

Trade-offs across Space, Time, and Ecosystem Services

Directory of Open Access Journals (Sweden)

Jon Paul. Rodríguez

2006-06-01

Full Text Available Ecosystem service (ES trade-offs arise from management choices made by humans, which can change the type, magnitude, and relative mix of services provided by ecosystems. Trade-offs occur when the provision of one ES is reduced as a consequence of increased use of another ES. In some cases, a trade-off may be an explicit choice; but in others, trade-offs arise without premeditation or even awareness that they are taking place. Trade-offs in ES can be classified along three axes: spatial scale, temporal scale, and reversibility. Spatial scale refers to whether the effects of the trade-off are felt locally or at a distant location. Temporal scale refers to whether the effects take place relatively rapidly or slowly. Reversibility expresses the likelihood that the perturbed ES may return to its original state if the perturbation ceases. Across all four Millennium Ecosystem Assessment scenarios and selected case study examples, trade-off decisions show a preference for provisioning, regulating, or cultural services (in that order. Supporting services are more likely to be "taken for granted." Cultural ES are almost entirely unquantified in scenario modeling; therefore, the calculated model results do not fully capture losses of these services that occur in the scenarios. The quantitative scenario models primarily capture the services that are perceived by society as more important - provisioning and regulating ecosystem services - and thus do not fully capture trade-offs of cultural and supporting services. Successful management policies will be those that incorporate lessons learned from prior decisions into future management actions. Managers should complement their actions with monitoring programs that, in addition to monitoring the short-term provisions of services, also monitor the long-term evolution of slowly changing variables. Policies can then be developed to take into account ES trade-offs at multiple spatial and temporal scales

Modeling anthropogenic and natural fire ignitions in an inner-alpine valley

Directory of Open Access Journals (Sweden)

G. Vacchiano

2018-03-01

Full Text Available Modeling and assessing the factors that drive forest fire ignitions is critical for fire prevention and sustainable ecosystem management. In southern Europe, the anthropogenic component of wildland fire ignitions is especially relevant. In the Alps, however, the role of fire as a component of disturbance regimes in forest and grassland ecosystems is poorly known. The aim of this work is to model the probability of fire ignition for an Alpine region in Italy using a regional wildfire archive (1995–2009 and MaxEnt modeling. We analyzed separately (i winter forest fires, (ii winter fires on grasslands and fallow land, and (iii summer fires. Predictors were related to morphology, climate, and land use; distance from infrastructures, number of farms, and number of grazing animals were used as proxies for the anthropogenic component. Collinearity among predictors was reduced by a principal component analysis. Regarding ignitions, 30 % occurred in agricultural areas and 24 % in forests. Ignitions peaked in the late winter–early spring. Negligence from agrosilvicultural activities was the main cause of ignition (64 %; lightning accounted for 9 % of causes across the study time frame, but increased from 6 to 10 % between the first and second period of analysis. Models for all groups of fire had a high goodness of fit (AUC 0.90–0.95. Temperature was proportional to the probability of ignition, and precipitation was inversely proportional. Proximity from infrastructures had an effect only on winter fires, while the density of grazing animals had a remarkably different effect on summer (positive correlation and winter (negative fires. Implications are discussed regarding climate change, fire regime changes, and silvicultural prevention. Such a spatially explicit approach allows us to carry out spatially targeted fire management strategies and may assist in developing better fire management plans.

Modeling anthropogenic and natural fire ignitions in an inner-alpine valley

Science.gov (United States)

Vacchiano, Giorgio; Foderi, Cristiano; Berretti, Roberta; Marchi, Enrico; Motta, Renzo

2018-03-01

Modeling and assessing the factors that drive forest fire ignitions is critical for fire prevention and sustainable ecosystem management. In southern Europe, the anthropogenic component of wildland fire ignitions is especially relevant. In the Alps, however, the role of fire as a component of disturbance regimes in forest and grassland ecosystems is poorly known. The aim of this work is to model the probability of fire ignition for an Alpine region in Italy using a regional wildfire archive (1995-2009) and MaxEnt modeling. We analyzed separately (i) winter forest fires, (ii) winter fires on grasslands and fallow land, and (iii) summer fires. Predictors were related to morphology, climate, and land use; distance from infrastructures, number of farms, and number of grazing animals were used as proxies for the anthropogenic component. Collinearity among predictors was reduced by a principal component analysis. Regarding ignitions, 30 % occurred in agricultural areas and 24 % in forests. Ignitions peaked in the late winter-early spring. Negligence from agrosilvicultural activities was the main cause of ignition (64 %); lightning accounted for 9 % of causes across the study time frame, but increased from 6 to 10 % between the first and second period of analysis. Models for all groups of fire had a high goodness of fit (AUC 0.90-0.95). Temperature was proportional to the probability of ignition, and precipitation was inversely proportional. Proximity from infrastructures had an effect only on winter fires, while the density of grazing animals had a remarkably different effect on summer (positive correlation) and winter (negative) fires. Implications are discussed regarding climate change, fire regime changes, and silvicultural prevention. Such a spatially explicit approach allows us to carry out spatially targeted fire management strategies and may assist in developing better fire management plans.

Supersingular quantum perturbations

International Nuclear Information System (INIS)

Detwiler, L.C.; Klauder, J.R.

1975-01-01

A perturbation potential is called supersingular whenever generally every matrix element of the perturbation in the unperturbed eigenstates is infinite. It follows that supersingular perturbations do not have conventional perturbation expansions, say for energy eigenvalues. By invoking variational arguments, we determine the asymptotic behavior of the energy eigenvalues for asymptotically small values of the coupling constant of the supersingular perturbation

Heavy Metals in Suburban Ecosystems of Industrial Centres and Ways of their Reduction

Directory of Open Access Journals (Sweden)

Onistratenko Nikolay Vladimirovich

2016-09-01

Full Text Available Technogenic contamination of ecosystems is one of the main dangers of our time. In order to reduce the harmful effects of this contamination and to provide cost-effective and environmentally safe food production methods, we are forced to look for ways of reliable analysis of the environmental situation, the selection systems of animal husbandry and regulations for the degree of impact of pollutants on the elements of the agroecosystem. This article presents the results of studies aimed at assessing the plight of the environment of a large industrial centre, and its anthropogenic impacts on every element of the suburban ecosystems. It presents data on maintenance and migration of anthropogenous pollutants in the trophic chains of pasturable ecosystems of the suburb of Volgograd. The authors have listed the industrial enterprises as the key sources of pollution. The features of the distribution of xenobiotics in the tissues and organs of calves and heifers of different breeds were analysed in the study. Conclusions were drawn on the accumulation of heavy metals and arsenic in cattle, and the impact of this factor on the quality of production. A comparative assessment of the resistance of different breeds of cows to the action of toxicants in the environment of the Lower Volga region was carried out. Ways to decrease the impact of pollutants on the cattle organism have also been suggested. The article pays attention to the environmental pollution of the industrial centre, the influence of these processes on all elements of an ecosystem including humans, and offers ways to minimize the damage.

Dissolved indium and rare earth elements in three Japanese rivers and Tokyo Bay: Evidence for anthropogenic Gd and In

Science.gov (United States)

Nozaki, Yoshiyuki; Lerche, Dorte; Alibo, Dia Sotto; Tsutsumi, Makoto

2000-12-01

New data on the dissolved (Thailand reported elsewhere (Nozaki et al., in press). Like Gd, the high dissolved In in the study area can also be ascribed to recent use of In-containing organic compound, In(DTPA) 2- in medical diagnosis. Thus, in the highly populated and industrialized area, dissolved heavy metal concentrations in rivers and estuaries may be significantly perturbed by human activities and the fate of those anthropogenic soluble substances in the marine environment needs to be investigated further.

Future Land-Use Changes and the Potential for Novelty in Ecosystems of the United States

Science.gov (United States)

Sebastian Martinuzzi; Gregorio I. Gavier-Pizarro; Ariel E. Lugo; Volker C. Radeloff

2015-01-01

Rapid global changes due to changing land use, climate, and non-native species are altering environmental conditions, resulting in more novel communities with unprecedented species combinations. Understanding how future anthropogenic changes may affect novelty in ecosystems is important to advance environmental management and ecological research in the Anthropocene....

Possible influence of anthropogenic aerosols on cirrus clouds and anthropogenic forcing

Directory of Open Access Journals (Sweden)

J. E. Penner

2009-02-01

Full Text Available Cirrus clouds have a net warming effect on the atmosphere and cover about 30% of the Earth's area. Aerosol particles initiate ice formation in the upper troposphere through modes of action that include homogeneous freezing of solution droplets, heterogeneous nucleation on solid particles immersed in a solution, and deposition nucleation of vapor onto solid particles. Here, we examine the possible change in ice number concentration from anthropogenic soot originating from surface sources of fossil fuel and biomass burning, from anthropogenic sulfate aerosols, and from aircraft that deposit their aerosols directly in the upper troposphere. We use a version of the aerosol model that predicts sulfate number and mass concentrations in 3-modes and includes the formation of sulfate aerosol through homogeneous binary nucleation as well as a version that only predicts sulfate mass. The 3-mode version best represents the Aitken aerosol nuclei number concentrations in the upper troposphere which dominated ice crystal residues in the upper troposphere. Fossil fuel and biomass burning soot aerosols with this version exert a radiative forcing of −0.3 to −0.4 Wm⁻² while anthropogenic sulfate aerosols and aircraft aerosols exert a forcing of −0.01 to 0.04 Wm⁻² and −0.16 to −0.12 Wm⁻², respectively, where the range represents the forcing from two parameterizations for ice nucleation. The sign of the forcing in the mass-only version of the model depends on which ice nucleation parameterization is used and can be either positive or negative. The magnitude of the forcing in cirrus clouds can be comparable to the forcing exerted by anthropogenic aerosols on warm clouds, but this forcing has not been included in past assessments of the total anthropogenic radiative forcing of climate.

AQUATOX coupled foodweb model for ecosystem risk assessment of Polybrominated diphenyl ethers (PBDEs) in lake ecosystems

International Nuclear Information System (INIS)

Zhang, Lulu; Liu, Jingling

2014-01-01

The AQUATOX model considers the direct toxic effects of chemicals and their indirect effects through foodwebs. For this study, the AQUATOX model was applied to evaluating the ecological risk of Polybrominated diphenyl ethers (PBDEs) in a highly anthropogenically disturbed lake-Baiyangdian Lake. Calibration and validation results indicated that the model can adequately describe the dynamics of 18 biological populations. Sensitivity analysis results suggested that the model is highly sensitive to temperature limitation. PBDEs risk estimate results demonstrate that estimated risk for natural ecosystems cannot be fully explained by single species toxicity data alone. The AQUATOX model could provide a good basis in ascertaining ecological protection levels of “chemicals of concern” for aquatic ecosystems. Therefore, AQUATOX can potentially be used to provide necessary information corresponding to early warning and rapid forecasting of pollutant transport and fate in the management of chemicals that put aquatic ecosystems at risk. - Highlights: • AQUATOX model incorporates direct toxic effects and indirect ecological effects. • Ecological risk of PBDEs was assessed by the AQUATOX model. • The model could help determine ecological threshold of “chemicals of concern”. - Capsule abstract: Application of the AQUATOX model to assess the direct and indirect ecological risk of PBDEs

Heavy metal pollution in immobile and mobile components of lentic ecosystems-a review.

Science.gov (United States)

Meena, Ramakrishnan Anu Alias; Sathishkumar, Palanivel; Ameen, Fuad; Yusoff, Abdull Rahim Mohd; Gu, Feng Long

2018-02-01

With growing population and urbanization, there is an increasing exploitation of natural resources, and this often results to environmental pollution. In this review, the levels of heavy metal in lentic compartments (water, sediment, fishes, and aquatic plants) over the past two decades (1997-2017) have been summarized to evaluate the current pollution status of this ecosystem. In all the compartments, the heavy metals dominated are zinc followed by iron. The major reason could be area mineralogy and lithogenic sources. Enormous quantity of metals like iron in estuarine sediment is a very natural incident due to the permanently reducing condition of organic substances. Contamination of cadmium, lead, and chromium was closely associated with anthropogenic origin. In addition, surrounding land use and atmospheric deposition could have been responsible for substantial pollution. The accumulation of heavy metals in fishes and aquatic plants is the result of time-dependent deposition in lentic ecosystems. Moreover, various potential risk assessment methods for heavy metals were discussed. This review concludes that natural phenomena dominate the accumulation of essential heavy metals in lentic ecosystems compared to anthropogenic sources. Amongst other recent reviews on heavy metals from other parts of the world, the present review is executed in such a way that it explains the presence of heavy metals not only in water environment, but also in the whole of the lentic system comprising sediment, fishes, and aquatic plants.

Towards a management perspective for coastal upwelling ecosystems

Energy Technology Data Exchange (ETDEWEB)

Howe, S.O.; Walsh, J.J.

1976-01-01

Data are reviewed from studies on the general distribution of upwelling of coastal waters, associated current patterns, and first order biological effects. Field observations and theory are discussed. Recent research has shown that variability and dynamism are the predominant characteristic features of these regions. Populations related by nonlinear interactions occur in constantly moving patches and swirls subjected to variability in the winds, currents, water chemistry, and solar insolation. Gross stationary features of upwelling communities have been described, but the responses of critical components and their relationships to human or natural perturbations remain poorly defined in this and other types of coastal ecosystems. Large scale research programs recognize that the continental shelf ecosystems are complex event-oriented phenomena. It is postulated that assessment of living resources in an environmental vacuum may lead to mismanagement and hindcasting rather than prescient management. A growing data base encourages the development of computer simulation models of ecosystem relationships and responses will lead to better understanding and management of these and other marine ecosystems in the future. 80 references.

Separating natural acidity from anthropogenic acidification in the spring flood of northern Sweden

International Nuclear Information System (INIS)

Laudon, Hjalmar

2000-01-01

Spring flood is an occasion for transient hydrochemical changes that profoundly effect the biodiversity of the aquatic ecosystem. Spring flood is also very susceptible to anthropogenic acidification. Belief that acid deposition is primarily responsible for pH decline during spring flood has been an important factor in the decision to spend close to one billion Swedish crowns to lime surface waters in northern Sweden during the last decade. The objective of this work is to present an operational tool, the Boreal Dilution Model (BDM), for separating and quantifying the anthropogenic and natural contributions to episodic acidification during spring flood episodes in northern Sweden. The limited data requirements of 10-15 stream water samples before and during spring flood make the BDM suitable for widespread use in environmental monitoring programs. This creates a possibility for distinguishing trends and spatial patterns in the human impact as well as natural pH decline. The results from applying the BDM, and a one point 'pBDM' version of the model, in northern Sweden demonstrate that the anthropogenic component associated with spring flood episodes is now generally limited. Instead it is the combination of natural organic acidity and dilution of the buffering capacity that is the major driving mechanism of episodic acidity during spring flood events in the region. While the anthropogenic component of episodic acidification generally contributes 0.1 to 0.3 pH units to the natural pH decline of up to 2.5 pH units, the current regional extent of areas that are severely affected by anthropogenically driven episodes is approximately 6%. Prior to the initiation of the Swedish Environmental Protection Agency's 'Episode Project' the limited spring flood data together with lack of a systematic methodology for determining liming candidates forced the liming authorities to base the remediation strategy in northern Sweden on biological indications. But, since there are more

The human footprint in the west: a large-scale analysis of anthropogenic impacts.

Science.gov (United States)

Leu, M.; Hanser, S.E.; Knick, S.T.

2008-01-01

Anthropogenic features such as urbanization, roads, and power lines, are increasing in western United States landscapes in response to rapidly growing human populations. However, their spatial effects have not been evaluated. Our goal was to model the human footprint across the western United States. We first delineated the actual area occupied by anthropogenic features, the physical effect area. Next, we developed the human footprint model based on the ecological effect area, the zone influenced by features beyond their physical presence, by combining seven input models: three models quantified top-down anthropogenic influences of synanthropic predators (avian predators, domestic dog and cat presence risk), and four models quantified bottom-up anthropogenic influences on habitat (invasion of exotic plants, human-caused fires, energy extraction, and anthropogenic wildland fragmentation). Using independent bird population data, we found bird abundance of four synanthropic species to correlate positively with human footprint intensity and negatively for three of the six species influenced by habitat fragmentation. We then evaluated the extent of the human footprint in relation to terrestrial (ecoregions) and aquatic systems (major rivers and lakes), regional management and conservation status, physical environment, and temporal changes in human actions. The physical effect area of anthropogenic features covered 13% of the western United States with agricultural land (9.8%) being most dominant. High-intensity human footprint areas (class 8–10) overlapped highly productive low-elevation private landholdings and covered 7% of the western United States compared to 48% for low-intensity areas (class 1–3), which were confined to low-productivity high-elevation federal landholdings. Areas within 1 km of rivers were more affected by the human footprint compared to lakes. Percentage human population growth was higher in low-intensity human footprint areas. The

Vegetation indicators of transformation in the urban forest ecosystems of "Kuzminki-Lyublino" Park

Science.gov (United States)

Buyvolova, Anna; Trifonova, Tatiana; Bykova, Elena

2017-04-01

Forest ecosystems in the city are at the same time a component of its natural environment and part of urban developmental planning. It imposes upon urban forests a large functional load, both environmental (formation of environment, air purification, noise pollution reducing, etc.) and social (recreational, educational) which defines the special attitude to their management and study. It is not a simple task to preserve maximum accessibility to the forest ecosystems of the large metropolises with a minimum of change. The urban forest vegetates in naturally formed soil, it has all the elements of a morphological structure (canopy layers), represented by natural species of the zonal vegetation. Sometimes it is impossible for a specialist to distinguish between an urban forest and a rural one. However, the urban forests are changing, being under the threat of various negative influences of the city, of which pollution is arguably the most significant. This article presents some indicators of structural changes to the plant communities, which is a response of forest ecosystems to an anthropogenic impact. It is shown that the indicators of the transformation of natural ecosystems in the city can be a reduction of the projective cover of moss layer, until its complete absence (in the pine forest), increasing the role of Acer negundo (adventive species) in the undergrowth, high variability of floristic indicators of the ground herbaceous vegetation, and a change in the spatial arrangement of adventive species. The assessment of the impact of the urban environment on the state of vegetation in the "Kuzminki-Lyublino" Natural-Historical Park was conducted in two key areas least affected by anthropogenic impacts under different plant communities represented by complex pine and birch forests and in similar forest types in the Prioksko-Terrasny Biosphere Reserve. The selection of pine forests as a model is due to the fact that, according to some scientists, pine (Pinus

Using ecosystem science to improve protection of the environment from radiation

Energy Technology Data Exchange (ETDEWEB)

Bradshaw, C. [Stockholm University (Sweden); Brechignac, F. [IUR / IRSN (France); Barnthouse, L. [LWB Environmental Services Inc. (United States); Brown, J. [Norwegian Radiation Protection Authority - NRPA (Norway); Forbes, V. [University of Lincoln (United Kingdom); Kapustka, L. [LC LK Consultancy (Canada); Kautsky, U. [Svensk Kaernbraenslehantering AB - SKB (Sweden)

2014-07-01

The ecosystem approach (EA) involves considering the impacts of an anthropogenic stressor at the ecosystem level because this is usually the ultimate goal of environmental protection. As such, EA includes population, community and ecosystem effects, structural and functional effects, indirect effects due to ecological interactions between species, dynamic interactions, positive or negative feedback loops, and potential synergistic or antagonistic effects of multiple stressors (both anthropogenic and natural). All such effects better reflect the reality of the impact of a contamination scenario than if assessments are restricted to considering effects to individual organisms or species. Such effects may be greater or lesser than expected from studies of individual organisms or species, so not considering them may result in under- or overestimation of risk, respectively. EA is a term that is widely used in environmental assessment, management and legislation in a number of regulatory fields (e.g., radiation protection, chemicals legislation, fisheries policy, international biodiversity conventions). However, although its justification is now well established in a wide range of environment protection contexts, its practical use is still unclear due to poorly defined protection goals and assessment endpoints, making its implementation difficult. This paper presents the initial findings of a newly formed follow-up task group of the International Union of Radioecology whose aims are to identify ways to put the EA into practice when considering protection of the environment from radiation. Drawing on knowledge and experience from a range of fields, we summarise the types of ecosystem processes, goods and services that might be included when using this approach, the science that supports the use of the EA, and the methodological challenges that need to be addressed when implementing the EA in the field of radiation protection. Document available in abstract form only

Predicting Vascular Plant Diversity in Anthropogenic Peatlands: Comparison of Modeling Methods with Free Satellite Data

Directory of Open Access Journals (Sweden)

Ivan Castillo-Riffart

2017-07-01

Full Text Available Peatlands are ecosystems of great relevance, because they have an important number of ecological functions that provide many services to mankind. However, studies focusing on plant diversity, addressed from the remote sensing perspective, are still scarce in these environments. In the present study, predictions of vascular plant richness and diversity were performed in three anthropogenic peatlands on Chiloé Island, Chile, using free satellite data from the sensors OLI, ASTER, and MSI. Also, we compared the suitability of these sensors using two modeling methods: random forest (RF and the generalized linear model (GLM. As predictors for the empirical models, we used the spectral bands, vegetation indices and textural metrics. Variable importance was estimated using recursive feature elimination (RFE. Fourteen out of the 17 predictors chosen by RFE were textural metrics, demonstrating the importance of the spatial context to predict species richness and diversity. Non-significant differences were found between the algorithms; however, the GLM models often showed slightly better results than the RF. Predictions obtained by the different satellite sensors did not show significant differences; nevertheless, the best models were obtained with ASTER (richness: R2 = 0.62 and %RMSE = 17.2, diversity: R2 = 0.71 and %RMSE = 20.2, obtained with RF and GLM respectively, followed by OLI and MSI. Diversity obtained higher accuracies than richness; nonetheless, accurate predictions were achieved for both, demonstrating the potential of free satellite data for the prediction of relevant community characteristics in anthropogenic peatland ecosystems.

Perturbation dynamics of the rumen microbiota in response to exogenous butyrate.

Directory of Open Access Journals (Sweden)

Robert W Li

Full Text Available The capacity of the rumen microbiota to produce volatile fatty acids (VFAs has important implications in animal well-being and production. We investigated temporal changes of the rumen microbiota in response to butyrate infusion using pyrosequencing of the 16S rRNA gene. Twenty one phyla were identified in the rumen microbiota of dairy cows. The rumen microbiota harbored 54.5±6.1 genera (mean ± SD and 127.3±4.4 operational taxonomic units (OTUs, respectively. However, the core microbiome comprised of 26 genera and 82 OTUs. Butyrate infusion altered molar percentages of 3 major VFAs. Butyrate perturbation had a profound impact on the rumen microbial composition. A 72 h-infusion led to a significant change in the numbers of sequence reads derived from 4 phyla, including 2 most abundant phyla, Bacteroidetes and Firmicutes. As many as 19 genera and 43 OTUs were significantly impacted by butyrate infusion. Elevated butyrate levels in the rumen seemingly had a stimulating effect on butyrate-producing bacteria populations. The resilience of the rumen microbial ecosystem was evident as the abundance of the microorganisms returned to their pre-disturbed status after infusion withdrawal. Our findings provide insight into perturbation dynamics of the rumen microbial ecosystem and should guide efforts in formulating optimal uses of probiotic bacteria treating human diseases.

Environmental contamination in Antarctic ecosystems.

Science.gov (United States)

Bargagli, R

2008-08-01

Although the remote continent of Antarctica is perceived as the symbol of the last great wilderness, the human presence in the Southern Ocean and the continent began in the early 1900s for hunting, fishing and exploration, and many invasive plant and animal species have been deliberately introduced in several sub-Antarctic islands. Over the last 50 years, the development of research and tourism have locally affected terrestrial and marine coastal ecosystems through fuel combustion (for transportation and energy production), accidental oil spills, waste incineration and sewage. Although natural "barriers" such as oceanic and atmospheric circulation protect Antarctica from lower latitude water and air masses, available data on concentrations of metals, pesticides and other persistent pollutants in air, snow, mosses, lichens and marine organisms show that most persistent contaminants in the Antarctic environment are transported from other continents in the Southern Hemisphere. At present, levels of most contaminants in Antarctic organisms are lower than those in related species from other remote regions, except for the natural accumulation of Cd and Hg in several marine organisms and especially in albatrosses and petrels. The concentrations of organic pollutants in the eggs of an opportunistic top predator such as the south polar skua are close to those that may cause adverse health effects. Population growth and industrial development in several countries of the Southern Hemisphere are changing the global pattern of persistent anthropogenic contaminants and new classes of chemicals have already been detected in the Antarctic environment. Although the Protocol on Environmental Protection to the Antarctic Treaty provides strict guidelines for the protection of the Antarctic environment and establishes obligations for all human activity in the continent and the Southern Ocean, global warming, population growth and industrial development in countries of the Southern

Historical overfishing and the recent collapse of coastal ecosystems.

Science.gov (United States)

Jackson, J B; Kirby, M X; Berger, W H; Bjorndal, K A; Botsford, L W; Bourque, B J; Bradbury, R H; Cooke, R; Erlandson, J; Estes, J A; Hughes, T P; Kidwell, S; Lange, C B; Lenihan, H S; Pandolfi, J M; Peterson, C H; Steneck, R S; Tegner, M J; Warner, R R

2001-07-27

Ecological extinction caused by overfishing precedes all other pervasive human disturbance to coastal ecosystems, including pollution, degradation of water quality, and anthropogenic climate change. Historical abundances of large consumer species were fantastically large in comparison with recent observations. Paleoecological, archaeological, and historical data show that time lags of decades to centuries occurred between the onset of overfishing and consequent changes in ecological communities, because unfished species of similar trophic level assumed the ecological roles of overfished species until they too were overfished or died of epidemic diseases related to overcrowding. Retrospective data not only help to clarify underlying causes and rates of ecological change, but they also demonstrate achievable goals for restoration and management of coastal ecosystems that could not even be contemplated based on the limited perspective of recent observations alone.

Non-perturbative versus perturbative renormalization of lattice operators

International Nuclear Information System (INIS)

Goeckeler, M.; Technische Hochschule Aachen; Horsley, R.; Ilgenfritz, E.M.; Oelrich, H.; Forschungszentrum Juelich GmbH; Schierholz, G.; Forschungszentrum Juelich GmbH; Perlt, H.; Schiller, A.; Rakow, P.

1995-09-01

Our objective is to compute the moments of the deep-inelastic structure functions of the nucleon on the lattice. A major source of uncertainty is the renormalization of the lattice operators that enter the calculation. In this talk we compare the renormalization constants of the most relevant twist-two bilinear quark operators which we have computed non-perturbatively and perturbatively to one loop order. Furthermore, we discuss the use of tadpole improved perturbation theory. (orig.)

7Be content in rainfall and soil deposition in South American coastal ecosystems

International Nuclear Information System (INIS)

Cardoso, R.; Ayub, J. Juri; Anjos, Roberto Meigikos dos; Cid, Alberto Silva; Velasco, H.

2011-01-01

Full text: Research about input, circulation and accumulation of natural and anthropogenic radionuclides in terrestrial ecosystems allows examining sources, establishing time scales and elucidating environmental processes. Thinking this way, researchers at UFF and UNSL have applied short-lived particle-reactive tracers to understand the behaviour of species evolution, functioning and restorations of natural and semi-natural ecosystems as well as to investigate the patterns and frequency of disturbances due to modern global changes. This can be accomplished through a detailed understanding on the hydrology and water circulation pattern, soil characteristics, erosion, resuspension, reduction/oxidation, speciation, precipitation and accumulation, diagenetic processes and microbial activities. 7 Be is a natural radionuclide (Eγ = 477.6 keV, t 1 / 2 = 53.3 d), which originates in the upper atmosphere as a result of bombardment by cosmic rays. The global distribution of this radionuclide provides a valuable means for testing and validating global circulation models on short time-scales. Its removal from the atmosphere by wet or dry deposition provides a useful tool for developing and validation of models about transport processes from the troposphere to the land surface. Knowledge of site-specific atmospheric fluxes is also crucial to evaluate the impact of atmospherically delivered pollutants on terrestrial ecosystems. The distribution of South American lands on different latitudes and its diversified topography can influence the development and action of many atmospheric systems contributing to generate non-homogeneous climatic conditions in this region. Increasing anthropogenic loads can further modify the precipitation rates and hence the climate of this region. Therefore it is important to study intra-system and inter-system interactions in different South American terrestrial ecosystems. Since 2006, UNSL has been investigating the 7 Be contents in rainfall and

Ecosystem Approach To Flood Disaster Risk Reduction

Directory of Open Access Journals (Sweden)

RK Kamble

2013-12-01

Full Text Available India is one of the ten worst disaster prone countries of the world. The country is prone to disasters due to number of factors; both natural and anthropogenic, including adverse geo-climatic conditions, topographical features, environmental degradation, population growth, urbanisation, industrlisation, non-scientific development practices etc. The factors either in original or by accelerating the intensity and frequency of disasters are responsible for heavy toll of human lives and disrupting the life support systems in the country. India has 40 million hectares of the flood-prone area, on an average, flood affect an area of around 7.5 million hectares per year. Knowledge of environmental systems and processes are key factors in the management of disasters, particularly the hydro-metrological ones. Management of flood risk and disaster is a multi-dimensional affair that calls for interdisciplinary approach. Ecosystem based disaster risk reduction builds on ecosystem management principles, strategies and tools in order to maximise ecosystem services for risk reduction. This perspective takes into account the integration of social and ecological systems, placing people at the centre of decision making. The present paper has been attempted to demonstrate how ecosystem-based approach can help in flood disaster risk reduction. International Journal of Environment, Volume-2, Issue-1, Sep-Nov 2013, Pages 70-82 DOI: http://dx.doi.org/10.3126/ije.v2i1.9209

Anthropogenic Decline of Ecosystem Services Threatens the Integrity of the Unique Hyrcanian (Caspian Forests in Northern Iran

Directory of Open Access Journals (Sweden)

Ardavan Zarandian

2016-02-01

Full Text Available The unique Hyrcanian (Caspian forests of northern Iran provide vital ecosystem services for local and global communities. We assess the status and trends of key ecosystem services in this region where native forest conversion has accelerated to make way for housing and farm development. This is a mountainous forested area that is valuable for both conservation and multiple human uses including recreation and farming. It contains globally significant natural habitats for in situ conservation of biological diversity. A rapid, qualitative, and participatory approach was used including interviews with local households and experts in combination with assessment of land use/cover remote sensing data to identify and map priority ecosystem services in the Geographic Information System (GIS. Based on the interests of the beneficiaries, eight priority services (food production, water supply, raw materials, soil conservation, water regulation, climate regulation, biodiversity, and recreation were identified and mapped. The results indicate the current typical spatial distribution of the provided services based on structural characteristics of the study landscape and their changing trends through a comparison of past, present and future land use, and land cover. Although food production and recreation have greatly increased in recent decades, the other services, in particular timber production, biodiversity, and water purification and supply are being gradually lost. The results of this study and of others elsewhere should raise awareness of ecosystem service status and trends and the value of examining these since they provide much of the information to inform natural resources policy and decision making. The declines in supply of key ecosystem services both within and outside the protected area are creating conflicts within communities as well as impacting on the integrity of the area and careful planning and conservation is required to provide win

Coastal livelihood transitions under globalization with implications for trans-ecosystem interactions.

Science.gov (United States)

Kramer, Daniel B; Stevens, Kara; Williams, Nicholas E; Sistla, Seeta A; Roddy, Adam B; Urquhart, Gerald R

2017-01-01

Anthropogenic threats to natural systems can be exacerbated due to connectivity between marine, freshwater, and terrestrial ecosystems, complicating the already daunting task of governance across the land-sea interface. Globalization, including new access to markets, can change social-ecological, land-sea linkages via livelihood responses and adaptations by local people. As a first step in understanding these trans-ecosystem effects, we examined exit and entry decisions of artisanal fishers and smallholder farmers on the rapidly globalizing Caribbean coast of Nicaragua. We found that exit and entry decisions demonstrated clear temporal and spatial patterns and that these decisions differed by livelihood. In addition to household characteristics, livelihood exit and entry decisions were strongly affected by new access to regional and global markets. The natural resource implications of these livelihood decisions are potentially profound as they provide novel linkages and spatially-explicit feedbacks between terrestrial and marine ecosystems. Our findings support the need for more scientific inquiry in understanding trans-ecosystem tradeoffs due to linked-livelihood transitions as well as the need for a trans-ecosystem approach to natural resource management and development policy in rapidly changing coastal regions.

Coastal livelihood transitions under globalization with implications for trans-ecosystem interactions.

Directory of Open Access Journals (Sweden)

Daniel B Kramer

Full Text Available Anthropogenic threats to natural systems can be exacerbated due to connectivity between marine, freshwater, and terrestrial ecosystems, complicating the already daunting task of governance across the land-sea interface. Globalization, including new access to markets, can change social-ecological, land-sea linkages via livelihood responses and adaptations by local people. As a first step in understanding these trans-ecosystem effects, we examined exit and entry decisions of artisanal fishers and smallholder farmers on the rapidly globalizing Caribbean coast of Nicaragua. We found that exit and entry decisions demonstrated clear temporal and spatial patterns and that these decisions differed by livelihood. In addition to household characteristics, livelihood exit and entry decisions were strongly affected by new access to regional and global markets. The natural resource implications of these livelihood decisions are potentially profound as they provide novel linkages and spatially-explicit feedbacks between terrestrial and marine ecosystems. Our findings support the need for more scientific inquiry in understanding trans-ecosystem tradeoffs due to linked-livelihood transitions as well as the need for a trans-ecosystem approach to natural resource management and development policy in rapidly changing coastal regions.

Extinction order and altered community structure rapidly disrupt ecosystem functioning.

Science.gov (United States)

Larsen, Trond H; Williams, Neal M; Kremen, Claire

2005-05-01

By causing extinctions and altering community structure, anthropogenic disturbances can disrupt processes that maintain ecosystem integrity. However, the relationship between community structure and ecosystem functioning in natural systems is poorly understood. Here we show that habitat loss appeared to disrupt ecosystem functioning by affecting extinction order, species richness and abundance. We studied pollination by bees in a mosaic of agricultural and natural habitats in California and dung burial by dung beetles on recently created islands in Venezuela. We found that large-bodied bee and beetle species tended to be both most extinction-prone and most functionally efficient, contributing to rapid functional loss. Simulations confirmed that extinction order led to greater disruption of function than predicted by random species loss. Total abundance declined with richness and also appeared to contribute to loss of function. We demonstrate conceptually and empirically how the non-random response of communities to disturbance can have unexpectedly large functional consequences.

Implications of overestimated anthropogenic CO2 emissions on East Asian and global land CO2 flux inversion

Science.gov (United States)

Saeki, Tazu; Patra, Prabir K.

2017-12-01

Measurement and modelling of regional or country-level carbon dioxide (CO2) fluxes are becoming critical for verification of the greenhouse gases emission control. One of the commonly adopted approaches is inverse modelling, where CO2 fluxes (emission: positive flux, sink: negative flux) from the terrestrial ecosystems are estimated by combining atmospheric CO2 measurements with atmospheric transport models. The inverse models assume anthropogenic emissions are known, and thus the uncertainties in the emissions introduce systematic bias in estimation of the terrestrial (residual) fluxes by inverse modelling. Here we show that the CO2 sink increase, estimated by the inverse model, over East Asia (China, Japan, Korea and Mongolia), by about 0.26 PgC year-1 (1 Pg = 1012 g) during 2001-2010, is likely to be an artifact of the anthropogenic CO2 emissions increasing too quickly in China by 1.41 PgC year-1. Independent results from methane (CH4) inversion suggested about 41% lower rate of East Asian CH4 emission increase during 2002-2012. We apply a scaling factor of 0.59, based on CH4 inversion, to the rate of anthropogenic CO2 emission increase since the anthropogenic emissions of both CO2 and CH4 increase linearly in the emission inventory. We find no systematic increase in land CO2 uptake over East Asia during 1993-2010 or 2000-2009 when scaled anthropogenic CO2 emissions are used, and that there is a need of higher emission increase rate for 2010-2012 compared to those calculated by the inventory methods. High bias in anthropogenic CO2 emissions leads to stronger land sinks in global land-ocean flux partitioning in our inverse model. The corrected anthropogenic CO2 emissions also produce measurable reductions in the rate of global land CO2 sink increase post-2002, leading to a better agreement with the terrestrial biospheric model simulations that include CO2-fertilization and climate effects.

Exploring the Impacts of Anthropogenic Disturbance on Seawater and Sediment Microbial Communities in Korean Coastal Waters Using Metagenomics Analysis

Directory of Open Access Journals (Sweden)

Nam-Il Won

2017-01-01

Full Text Available The coastal ecosystems are considered as one of the most dynamic and vulnerable environments under various anthropogenic developments and the effects of climate change. Variations in the composition and diversity of microbial communities may be a good indicator for determining whether the marine ecosystems are affected by complex forcing stressors. DNA sequence-based metagenomics has recently emerged as a promising tool for analyzing the structure and diversity of microbial communities based on environmental DNA (eDNA. However, few studies have so far been performed using this approach to assess the impacts of human activities on the microbial communities in marine systems. In this study, using metagenomic DNA sequencing (16S ribosomal RNA gene, we analyzed and compared seawater and sediment communities between sand mining and control (natural sites in southern coastal waters of Korea to assess whether anthropogenic activities have significantly affected the microbial communities. The sand mining sites harbored considerably lower levels of microbial diversities in the surface seawater community during spring compared with control sites. Moreover, the sand mining areas had distinct microbial taxonomic group compositions, particularly during spring season. The microbial groups detected solely in the sediment load/dredging areas (e.g., Marinobacter, Alcanivorax, Novosphingobium are known to be involved in degradation of toxic chemicals such as hydrocarbon, oil, and aromatic compounds, and they also contain potential pathogens. This study highlights the versatility of metagenomics in monitoring and diagnosing the impacts of human disturbance on the environmental health of marine ecosystems from eDNA.

Irregular focal mechanisms observed at Salton Sea Geothermal Field: Possible influences of anthropogenic stress perturbations

Science.gov (United States)

Crandall-Bear, Aren; Barbour, Andrew J.; Schoenball, Martin; Schoenball, Martin

2018-01-01

At the Salton Sea Geothermal Field (SSGF), strain accumulation is released through seismic slip and aseismic deformation. Earthquake activity at the SSGF often occurs in swarm-like clusters, some with clear migration patterns. We have identified an earthquake sequence composed entirely of focal mechanisms representing an ambiguous style of faulting, where strikes are similar but deformation occurs due to steeply-dipping normal faults with varied stress states. In order to more accurately determine the style of faulting for these events, we revisit the original waveforms and refine estimates of P and S wave arrival times and displacement amplitudes. We calculate the acceptable focal plane solutions using P-wave polarities and S/P amplitude ratios, and determine the preferred fault plane. Without constraints on local variations in stress, found by inverting the full earthquake catalog, it is difficult to explain the occurrence of such events using standard fault-mechanics and friction. Comparing these variations with the expected poroelastic effects from local production and injection of geothermal fluids suggests that anthropogenic activity could affect the style of faulting.

Status of coral reefs of Upolu (Independent State of Samoa) in the South West Pacific and recommendations to promote resilience and recovery of coastal ecosystems

KAUST Repository

Ziegler, Maren

2018-03-23

Coral reef ecosystems worldwide are immediately threatened by the impacts of climate change. Here we report on the condition of coral reefs over 83 km of coastline at the island of Upolu, Samoa in the remote South West Pacific in 2016 during the Tara Pacific Expedition. Despite the distance to large urban centers, coral cover was extremely low (<1%) at approximately half of the sites and below 10% at 78% of sites. Two reef fish species, Acanthurus triostegus and Zanclus cornutus, were 10% smaller at Upolu than at neighboring islands. Importantly, coral cover was higher within marine protected areas, indicating that local management action remains a useful tool to support the resilience of local reef ecosystems to anthropogenic impacts. This study may be interpreted as cautionary sign for reef ecosystem health in remote locations on this planet, reinforcing the need to immediately reduce anthropogenic impacts on a global scale.

Status of coral reefs of Upolu (Independent State of Samoa) in the South West Pacific and recommendations to promote resilience and recovery of coastal ecosystems

KAUST Repository

Ziegler, Maren; Qué ré , Gaë lle; Ghiglione, Jean-Franç ois; Iwankow, Guillaume; Barbe, Valé rie; Boissin, Emilie; Wincker, Patrick; Planes, Serge; Voolstra, Christian R.

2018-01-01

Coral reef ecosystems worldwide are immediately threatened by the impacts of climate change. Here we report on the condition of coral reefs over 83 km of coastline at the island of Upolu, Samoa in the remote South West Pacific in 2016 during the Tara Pacific Expedition. Despite the distance to large urban centers, coral cover was extremely low (<1%) at approximately half of the sites and below 10% at 78% of sites. Two reef fish species, Acanthurus triostegus and Zanclus cornutus, were 10% smaller at Upolu than at neighboring islands. Importantly, coral cover was higher within marine protected areas, indicating that local management action remains a useful tool to support the resilience of local reef ecosystems to anthropogenic impacts. This study may be interpreted as cautionary sign for reef ecosystem health in remote locations on this planet, reinforcing the need to immediately reduce anthropogenic impacts on a global scale.

Assessing Freshwater Ecosystem Service Risk over Ecological, Socioeconomic, and Cultural Gradients: Problem Space Characterization and Methodology

Science.gov (United States)

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

2014-12-01

Freshwater ecosystems and the services they provide are under increasing anthropogenic pressure at local (e.g., irrigation diversions, wastewater discharge) and global scales (e.g., climate change, global trading). The impact depends on an ecosystem's sensitivity, which is determined by its geophysical and ecological settings, and the population and activities in its surrounding watershed. Given the importance of ecosystem services, it is critical that we improve our ability to identify and understand changes in aquatic ecosystems, and translate them to risk of service loss. Furthermore, to inspire changes in human behavior, it is equally critical that we learn to communicate risk, and pose risk mitigation strategies, in a manner acceptable to a broad spectrum of stakeholders. Quantifying the nature and timing of the risk is difficult because (1) we often fail to understand the connection between anthropogenic pressures and the timing and extent of ecosystem changes; and (2) the concept of risk is inherently coupled to human perception, which generally differs with cultural and socio-economic conditions. In this study, we endeavor to assess aquatic ecosystem risks across an international array of six study sites. The challenge is to construct a methodology capable of capturing the marked biogeographical, socioeconomic, and cultural differences among the sites, which include: (1) Muskoka River watershed in humid continental Ontario, Canada; (2) Lower San Joaquin River, an impounded snow-fed river in semi-arid Central California; (3) Ciénaga Grande de Santa Marta, a tropical coastal lagoon in Colombia; (4) Senguer River basin in the semi-arid part of Argentina; (5) Laguna de Rocha watershed in humid subtropical Uruguay; and (6) Palomas Lake complex in oceanic Chilean Patagonia. Results will include a characterization of the experimental gradient over the six sites, an overview of the risk assessment methodology, and preliminary findings for several of the sites.

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

Science.gov (United States)

Brook, John; Yates, Kimberly; Halley, Robert

2006-01-01

Worldwide, local-scale anthropogenic stress combined with global climate change is driving shifts in the state of reef benthic communities from coral-rich to micro- or macroalgal-dominated (Knowlton, 1992; Done, 1999). Such phase shifts in reef benthic communities may be either abrupt or gradual, and case studies from diverse ocean basins demonstrate that recovery, while uncertain (Hughes, 1994), typically involves progression through successional stages (Done, 1992). These transitions in benthic community structure involve changes in community metabolism, and accordingly, the holistic evaluation of associated biogeochemical variables is of great intrinsic value (Done, 1992). Effective reef management requires advance prediction of coral reef alteration in the face of anthropogenic stress and change in the global environment (Hatcher, 1997a). In practice, this goal requires techniques that can rapidly discern, at an early stage, sublethal effects that may cause long-term increases in mortality (brown, 1988; Grigg and Dollar, 1990). Such methods would improve our understanding of the differences in the population, community, and ecosystem structure, as well as function, between pristine and degraded reefs. This knowledge base could then support scientifically based management strategies (Done, 1992). Brown (1988) noted the general lack of rigor in the assessment of stress on coral reefs and suggested that more quantitative approaches than currently exist are needed to allow objective understanding of coral reef dynamics. Sensitive techniques for the timely appraisal of pollution effects or generalized endemic stress in coral reefs are sorely lacking (Grigg and Dollar, 1990; Wilkinsin, 1992). Moreover, monitoring methods based on population inventories, sclerochronology, or reproductive biology tend to myopic and may give inconsistent results. Ideally, an improved means of evaluating reef stress would discriminate mortality due to natural causes from morality to

Mapping Woodland Cover in the Miombo Ecosystem: A Comparison of Machine Learning Classifiers

Directory of Open Access Journals (Sweden)

Courage Kamusoko

2014-06-01

Full Text Available Miombo woodlands in Southern Africa are experiencing accelerated changes due to natural and anthropogenic disturbances. In order to formulate sustainable woodland management strategies in the Miombo ecosystem, timely and up-to-date land cover information is required. Recent advances in remote sensing technology have improved land cover mapping in tropical evergreen ecosystems. However, woodland cover mapping remains a challenge in the Miombo ecosystem. The objective of the study was to evaluate the performance of decision trees (DT, random forests (RF, and support vector machines (SVM in the context of improving woodland and non-woodland cover mapping in the Miombo ecosystem in Zimbabwe. We used Multidate Landsat 8 spectral and spatial dependence (Moran’s I variables to map woodland and non-woodland cover. Results show that RF classifier outperformed the SVM and DT classifiers by 4% and 15%, respectively. The RF importance measures show that multidate Landsat 8 spectral and spatial variables had the greatest influence on class-separability in the study area. Therefore, the RF classifier has potential to improve woodland cover mapping in the Miombo ecosystem.

Structure, functioning, and cumulative stressors of Mediterranean deep-sea ecosystems

OpenAIRE

Tecchio, S.; Coll, Marta; Sarda, F.

2015-01-01

Environmental stressors, such as climate fluctuations, and anthropogenic stressors, such as fishing, are of major concern for the management of deep-sea ecosystems. Deep-water habitats are limited by primary productivity and are mainly dependent on the vertical input of organic matter from the surface. Global change over the latest decades is imparting variations in primary productivity levels across oceans, and thus it has an impact on the amount of organic matter landing on the deep seafloo...

Coral microbial community dynamics in response to anthropogenic impacts near a major city in the central Red Sea

KAUST Repository

Ziegler, Maren; Roik, Anna Krystyna; Porter, Adam; Zubier, Khalid; Mudarris, Mohammed S.; Ormond, Rupert; Voolstra, Christian R.

2016-01-01

Coral-associated bacteria play an increasingly recognized part in coral health. We investigated the effect of local anthropogenic impacts on coral microbial communities on reefs near Jeddah, the largest city on the Saudi Arabian coast of the central Red Sea. We analyzed the bacterial community structure of water and corals (Pocillopora verrucosa and Acropora hemprichii) at sites that were relatively unimpacted, exposed to sedimentation & local sewage, or in the discharge area of municipal wastewaters. Coral microbial communities were significantly different at impacted sites: in both corals the main symbiotic taxon decreased in abundance. In contrast, opportunistic bacterial families, such as e.g. Vibrionaceae and Rhodobacteraceae, were more abundant in corals at impacted sites. In conclusion, microbial community response revealed a measurable footprint of anthropogenic impacts to coral ecosystems close to Jeddah, even though the corals appeared visually healthy.

Coral microbial community dynamics in response to anthropogenic impacts near a major city in the central Red Sea

KAUST Repository

Ziegler, Maren

2016-01-04

Coral-associated bacteria play an increasingly recognized part in coral health. We investigated the effect of local anthropogenic impacts on coral microbial communities on reefs near Jeddah, the largest city on the Saudi Arabian coast of the central Red Sea. We analyzed the bacterial community structure of water and corals (Pocillopora verrucosa and Acropora hemprichii) at sites that were relatively unimpacted, exposed to sedimentation & local sewage, or in the discharge area of municipal wastewaters. Coral microbial communities were significantly different at impacted sites: in both corals the main symbiotic taxon decreased in abundance. In contrast, opportunistic bacterial families, such as e.g. Vibrionaceae and Rhodobacteraceae, were more abundant in corals at impacted sites. In conclusion, microbial community response revealed a measurable footprint of anthropogenic impacts to coral ecosystems close to Jeddah, even though the corals appeared visually healthy.

Bioecological principles of maintaining stability in mountain forest ecosystems of the Ukrainian Carpathians

Directory of Open Access Journals (Sweden)

T. V. Parpan

2016-09-01

Full Text Available The forest cover of the Carpathians has been deeply transformed by productive activities over the past centuries. The forest cover, age and species structure of its ecosystems have been changed. Beech and fir forests were replaced by spruce monocultures. Consequently, nitrogen and mineral elements cycles changed, the genetic and population structures altered and the eco-stabilizing function of forests decreased. These negative trends make it desirable to process the bioecological principles of maintenance the stability of mountain forest ecosystems. The proposed bioecological principles of support and recovery of stability of forest ecosystems are part of the paradigm of mountain dendrology and silviculture. The strategy is based on maintaining bio-ecological and population-genetical features of the main forest forming species, evolutionary typological classification of the forests, landscape and environmental specifics of the mountain part of the Ukrainian Carpathians, features of virgin, old growth and anthropogenically disturbed forest structures, as well as performing the functional role of forest ecosystems. Support for landscape ecosystem stability involves the conservation, selective, health and gradual cutting, formation of forest stands which are close to natural conditions and focusing on natural regeneration (a basis for stable mountain forest ecosystems.

Towards better monitoring of technology critical elements in Europe: Coupling of natural and anthropogenic cycles.

Science.gov (United States)

Nuss, Philip; Blengini, Gian Andrea

2018-02-01

The characterization of elemental cycles has a rich history in biogeochemistry. Well known examples include the global carbon cycle, or the cycles of the 'grand nutrients' nitrogen, phosphorus, and sulfur. More recently, efforts have increased to better understand the natural cycling of technology critical elements (TCEs), i.e. elements with a high supply risk and economic importance in the EU. On the other hand, tools such as material-flow analysis (MFA) can help to understand how substances and goods are transported and accumulated in man-made technological systems ('anthroposphere'). However, to date both biogeochemical cycles and MFA studies suffer from narrow system boundaries, failing to fully illustrate relative anthropogenic and natural flow magnitude and the degree to which human activity has perturbed the natural cycling of elements. We discuss important interconnections between natural and anthropogenic cycles and relevant EU raw material dossiers. Increased integration of both cycles could help to better capture the transport and fate of elements in nature including their environmental/human health impacts, highlight potential future material stocks in the anthroposphere (in-use stocks) and in nature (e.g., in soils, tailings, or mining wastes), and estimate anticipated emissions of TCEs to nature in the future (based on dynamic stock modeling). A preliminary assessment of natural versus anthropogenic element fluxes indicates that anthropogenic fluxes induced by the EU-28 of palladium, platinum, and antimony (as a result of materials uses) might be greater than the respective global natural fluxes. Increased combination of MFA and natural cycle data at EU level could help to derive more complete material cycles and initiate a discussion between the research communities of biogeochemists and material flow analysts to more holistically address the issues of sustainable resource management. Copyright © 2017 The Authors. Published by Elsevier B.V. All

The Baltic Sea as a time machine for the future coastal ocean

DEFF Research Database (Denmark)

Reusch, Thorsten B. H.; Dierking, Jan; Andersson, Helen C.

2018-01-01

Coastal global oceans are expected to undergo drastic changes driven by climate change and increasing anthropogenic pressures in coming decades. Predicting specific future conditions and assessing the best management strategies to maintain ecosystem integrity and sustainable resource use are diff......Coastal global oceans are expected to undergo drastic changes driven by climate change and increasing anthropogenic pressures in coming decades. Predicting specific future conditions and assessing the best management strategies to maintain ecosystem integrity and sustainable resource use...... are difficult, because of multiple interacting pressures, uncertain projections, and a lack of test cases for management. We argue that the Baltic Sea can serve as a time machine to study consequences and mitigation of future coastal perturbations, due to its unique combination of an early history...... of multistressor disturbance and ecosystem deterioration and early implementation of cross-border environmental management to address these problems. The Baltic Sea also stands out in providing a strong scientific foundation and accessibility to long-term data series that provide a unique opportunity to assess...

Microbial Functional Gene Diversity Predicts Groundwater Contamination and Ecosystem Functioning

Science.gov (United States)

Zhang, Ping; Wu, Linwei; Rocha, Andrea M.; Shi, Zhou; Wu, Bo; Qin, Yujia; Wang, Jianjun; Yan, Qingyun; Curtis, Daniel; Ning, Daliang; Van Nostrand, Joy D.; Wu, Liyou; Watson, David B.; Adams, Michael W. W.; Alm, Eric J.; Adams, Paul D.; Arkin, Adam P.

2018-01-01

ABSTRACT Contamination from anthropogenic activities has significantly impacted Earth’s biosphere. However, knowledge about how environmental contamination affects the biodiversity of groundwater microbiomes and ecosystem functioning remains very limited. Here, we used a comprehensive functional gene array to analyze groundwater microbiomes from 69 wells at the Oak Ridge Field Research Center (Oak Ridge, TN), representing a wide pH range and uranium, nitrate, and other contaminants. We hypothesized that the functional diversity of groundwater microbiomes would decrease as environmental contamination (e.g., uranium or nitrate) increased or at low or high pH, while some specific populations capable of utilizing or resistant to those contaminants would increase, and thus, such key microbial functional genes and/or populations could be used to predict groundwater contamination and ecosystem functioning. Our results indicated that functional richness/diversity decreased as uranium (but not nitrate) increased in groundwater. In addition, about 5.9% of specific key functional populations targeted by a comprehensive functional gene array (GeoChip 5) increased significantly (P contamination and ecosystem functioning. This study indicates great potential for using microbial functional genes to predict environmental contamination and ecosystem functioning. PMID:29463661

Modeling Temporal and Spatial Flows of Ecosystem Services in Chittenden County, VT

Science.gov (United States)

Voigt, B. G.; Bagstad, K.; Johnson, G.; Villa, F.

2010-12-01

This paper documents the integration of ARIES (ARtificial Intelligence for Ecosystem Services) with the land use change model UrbanSim to explore the impacts of current and future land use patterns on flood protection and water provision services in Chittenden County, VT. ARIES, an open source modeling platform, is particularly well-suited for measuring, mapping, and modeling the temporal and spatial flows of ecosystem services across the landscape, linking the areas of provision (sources) with human beneficiaries (users) through a spatially explicit agent-based modeling approach. UrbanSim is an open source agent-based land use model designed to facilitate a wide-range of scenarios based on user-specified behavioral assumptions, zoning regulations, and demographic, economic, and infrastructure (e.g. transportation, water, sewer, etc.) parameters. Ecosystem services travel through time and space and are susceptible to disruption and destruction from both natural and anthropogenic perturbations. The conversion of forested or agricultural land to urbanizing uses is replete with a long history of hydrologic impairment, habitat fragmentation, and the degradation of sensitive landscapes. Development decisions are predicated on the presence of landscape characteristics that meet the needs of developers and satisfy the desires of consumers, with minimal consideration of access to or effect on the provision of ecosystem services. The County houses nearly 25% of the state’s population and several employment centers that draw labor from throughout the region. Additionally, the County is expected to maintain modest residential and employment growth over the next 30 years, and will continue to serve as the state’s population and employment center. Expected future growth is likely to adversely affect the remaining farm and forest land in the County in the absence of policies to support sustainable development. We demonstrate how ARIES can be used to quantify changes in

What does it mean to put caribou knowledge into an ecosystem context?

Directory of Open Access Journals (Sweden)

Fred H. Harrington

1998-03-01

Full Text Available Ecosystems are envisioned as integrated, complex systems with both living and non-living components, that are linked through processes of energy flow and nutrient cycling (Bowen, 1971; Ricklefs, 1979. The ecosystem approach seeks to describe the components of this system, the pathways through which energy and nutrients move, and the processes that govern that movement. The goal is a better understanding of the role or effect of each component (abiotic or biotic within the system. Theorerically, the more we know, the better we can predict the future behaviour of the ecosystem and therefore manage the system on whatever sustainable basis we deem appropriate. Caribou (Rangifer tarandus presently inhabit two ecosystems, tundra (arctic and alpine and taiga (or boreal forest, both characterized by relatively low productivity and diversity (Bowen, 1971; Bliss, 1981; Bonan, 1992a. As increased anthropogenic impacts are expected in these ecosystems through the next century, our ability to ensure the continued survival of caribou requires that we pay increasing attention to the processes that drive these systems. In this endeavour, an awareness of the effects of both spatial and temporal scale, in both ecosystem processes and our research programs to understand those processes, is critical.

Geospatial technology perspectives for mining vis-a-vis sustainable forest ecosystems

Directory of Open Access Journals (Sweden)

Goparaju Laxmi

2017-06-01

Full Text Available Forests, the backbone of biogeochemical cycles and life supporting systems, are under severe pressure due to varied anthropogenic activities. Mining activities are one among the major reasons for forest destruction questioning the survivability and sustainability of flora and fauna existing in that area. Thus, monitoring and managing the impact of mining activities on natural resources at regular intervals is necessary to check the status of their depleted conditions, and to take up restoration and conservative measurements. Geospatial technology provides means to identify the impact of different mining operations on forest ecosystems and helps in proposing initiatives for safeguarding the forest environment. In this context, the present study highlights the problems related to mining in forest ecosystems and elucidates how geospatial technology can be employed at various stages of mining activities to achieve a sustainable forest ecosystem. The study collates information from various sources and highlights the role of geospatial technology in mining industries and reclamation process.

Evolutionary responses by native species to major anthropogenic changes to their ecosystems: Pacific salmon in the Columbia River hydropower system.

Science.gov (United States)

Waples, Robin S; Zabel, Richard W; Scheuerell, Mark D; Sanderson, Beth L

2008-01-01

The human footprint is now large in all the Earth's ecosystems, and construction of large dams in major river basins is among the anthropogenic changes that have had the most profound ecological consequences, particularly for migratory fishes. In the Columbia River basin of the western USA, considerable effort has been directed toward evaluating demographic effects of dams, yet little attention has been paid to evolutionary responses of migratory salmon to altered selective regimes. Here we make a first attempt to address this information gap. Transformation of the free-flowing Columbia River into a series of slack-water reservoirs has relaxed selection for adults capable of migrating long distances upstream against strong flows; conditions now favour fish capable of migrating through lakes and finding and navigating fish ladders. Juveniles must now be capable of surviving passage through multiple dams or collection and transportation around the dams. River flow patterns deliver some groups of juvenile salmon to the estuary later than is optimal for ocean survival, but countervailing selective pressures might constrain an evolutionary response toward earlier migration timing. Dams have increased the cost of migration, which reduces energy available for sexual selection and favours a nonmigratory life history. Reservoirs are a benign environment for many non-native species that are competitors with or predators on salmon, and evolutionary responses are likely (but undocumented). More research is needed to tease apart the relative importance of evolutionary vs. plastic responses of salmon to these environmental changes; this research is logistically challenging for species with life histories like Pacific salmon, but results should substantially improve our understanding of key processes. If the Columbia River is ever returned to a quasinatural, free-flowing state, remaining populations might face a Darwinian debt (and temporarily reduced fitness) as they struggle to

Effects of acidification on olfactory-mediated behaviour in freshwater and marine ecosystems: a synthesis

OpenAIRE

Leduc, Antoine O. H. C.; Munday, Philip L.; Brown, Grant E.; Ferrari, Maud C. O.

2013-01-01

For many aquatic organisms, olfactory-mediated behaviour is essential to the maintenance of numerous fitness-enhancing activities, including foraging, reproduction and predator avoidance. Studies in both freshwater and marine ecosystems have demonstrated significant impacts of anthropogenic acidification on olfactory abilities of fish and macroinvertebrates, leading to impaired behavioural responses, with potentially far-reaching consequences to population dynamics and community structure. Wh...

Integrated Assessment of the impact of Aqueous Contaminant Stressors on Surface Water Ecosystems

DEFF Research Database (Denmark)

McKnight, Ursula S.; Rasmussen, Jes J.; Kronvang, Brian

2011-01-01

ecosystems. Traditional approaches for managing aquatic resources have often failed to account for the potential effects of anthropogenic disturbances on biota. To fulfil the requirements of the EU Water Framework Directive will be challenging, as it is difficult to successfully separate and evaluate all...... pressures stressing an ecosystem. Here, methods for determining ecological status in streams are evaluated to see if they are capable of capturing the effects of stressors potentially affecting ecosystems. Specifically, they are tested on a case study where the effects of physical habitat degradation can...... be ruled out as a stressor on stream ecological conditions (Rasmussen et al., 2011). This study follows earlier work conducted on a Danish case study involving a TCE groundwater plume discharging into a small stream, located in an area with protected drinking water interests (McKnight et al., 2010...

Poverty, development, and Himalayan ecosystems.

Science.gov (United States)

Sandhu, Harpinder; Sandhu, Sukhbir

2015-05-01

The Himalayas are rich in biodiversity but vulnerable to anthropogenic pressures. They are also host to growing number of rural poor who are dependent on forest and ecosystem services for their livelihood. Local and global efforts to integrate poverty alleviation and biodiversity conservation in the Himalayas remain elusive so far. In this work, we highlight two key impediments in achieving sustainable development in the Himalayas. On the positive side, we also highlight the work of Ashoka Trust for Research in Ecology and the Environment (ATREE), a research organization based in India that seeks to integrate biodiversity concerns with livelihood security. For impediments, we draw on two examples from the Darjeeling district, India, in Eastern Himalayan region to illustrate how development organizations are failing to simultaneously address poverty and environmental issues. Based on the success of ATREE, we then propose a conceptual framework to integrate livelihood generating activities with sustainable and equitable development agenda. We recommend developing a Hindu-Kush Himalayan Ecosystem Services Network in the region to formulate a strategy for further action. We conclude by offering measures to address the challenge of integrating livelihood and environment issues through this network.

Anthropogenic CO2 in the ocean

Directory of Open Access Journals (Sweden)

Tsung-Hung Peng

2005-06-01

Full Text Available The focus of this review article is on the anthropogenic CO2 taken up by the ocean. There are several methods of identifying the anthropogenic CO2 signal and quantifying its inventory in the ocean. The ?C* method is most frequently used to estimate the global distribution of anthropogenic CO2 in the ocean. Results based on analysis of the dataset obtained from the comprehensive surveys of inorganic carbon distribution in the world oceans in the 1990s are given. These surveys were jointly conducted during the World Ocean Circulation Experiment (WOCE and the Joint Global Ocean Flux Study (JGOFS. This data set consists of 9618 hydrographic stations from a total of 95 cruises, which represents the most accurate and comprehensive view of the distribution of inorganic carbon in the global ocean available today. The increase of anthropogenic CO2 in the ocean during the past few decades is also evaluated using direct comparison of results from repeat surveys and using statistical method of Multi-parameter Linear Regression (MLR. The impact of increasing oceanic anthropogenic CO2 on the calcium carbonate system in the ocean is reviewed briefly as well. Extensive studies of CaCO3 dissolution as a result of increasing anthropogenic CO2 in the ocean have revealed several distinct oceanic regions where the CaCO3 undersaturation zone has expanded.

Effects of land cover and regional climate variations on long-term spatiotemporal changes in sagebrush ecosystems

Science.gov (United States)

Xian, George Z.; Homer, Collin G.; Aldridge, Cameron L.

2012-01-01

This research investigated the effects of climate and land cover change on variation in sagebrush ecosystems. We combined information of multi-year sagebrush distribution derived from multitemporal remote sensing imagery and climate data to study the variation patterns of sagebrush ecosystems under different potential disturbances. We found that less than 40% of sagebrush ecosystem changes involved abrupt changes directly caused by landscape transformations and over 60% of the variations involved gradual changes directly related to climatic perturbations. The primary increases in bare ground and declines in sagebrush vegetation abundance were significantly correlated with the 1996-2006 decreasing trend in annual precipitation.

A probabilistic model of ecosystem response to climate change

International Nuclear Information System (INIS)

Shevliakova, E.; Dowlatabadi, H.

1994-01-01

Anthropogenic activities are leading to rapid changes in land cover and emissions of greenhouse gases into the atmosphere. These changes can bring about climate change typified by average global temperatures rising by 1--5 C over the next century. Climate change of this magnitude is likely to alter the distribution of terrestrial ecosystems on a large scale. Options available for dealing with such change are abatement of emissions, adaptation, and geoengineering. The integrated assessment of climate change demands that frameworks be developed where all the elements of the climate problem are present (from economic activity to climate change and its impacts on market and non-market goods and services). Integrated climate assessment requires multiple impact metrics and multi-attribute utility functions to simulate the response of different key actors/decision-makers to the actual physical impacts (rather than a dollar value) of the climate-damage vs. policy-cost debate. This necessitates direct modeling of ecosystem impacts of climate change. The authors have developed a probabilistic model of ecosystem response to global change. This model differs from previous efforts in that it is statistically estimated using actual ecosystem and climate data yielding a joint multivariate probability of prevalence for each ecosystem, given climatic conditions. The authors expect this approach to permit simulation of inertia and competition which have, so far, been absent in transfer models of continental-scale ecosystem response to global change. Thus, although the probability of one ecotype will dominate others at a given point, others would have the possibility of establishing an early foothold

Fungi and their role in corals and coral reef ecosystems

Digital Repository Service at National Institute of Oceanography (India)

Raghukumar, C.; Ravindran, J.

fungal hyphae have on corals, their mechanism of penetration and the role their enzymes play in this process. 3.2. Fungi as pathogens in reef ecosystems Besides natural disasters and climate warming, diseases have contributed to coral decline... defence mechanisms against predation, biofouling, diseases, environmental perturbations and other stressors. These chemicals are either synthesized by the organisms themselves or their endobiontic microorganisms. If these valuable compounds...

Task group of international union of radioecology 'ecosystem approach to environment protection'

International Nuclear Information System (INIS)

Fuma, Shoichi

2011-01-01

An ecosystem approach is a holistic (i.e., top-down) strategy for protection of ecosystem structures and functions from perturbations. A task group of International Union of Radioecology 'Ecosystem Approach to Environment Protection' was launched in April, 2010. This task group is preparing a report on the following topics: (1) goals of environmental protection; (2) legislation about environmental protection; (3) assessment of the Reference Animals and Plants (RAP) concept in the general context of environmental protection; (4) limitations and uncertainties of the RAPs concept; (5) justification and merits of the ecosystem approach; (6) assessing the feasibility of the ecosystem approach; (7) research and development required for the ecosystem approach; and (8) recommendations with respect to radiation protection. The topics 1, 3, 4 and 5 have been almost completely prepared, and demonstrate that the ecosystem approach is required for radiation protection of the environment. On the other hand, methods of the ecosystem approach which should be adopted for radiation protection of the environment are not clear in the current draft report. They should be specified by reviewing the Convention on Biological Diversity, fish stock management and other activities where the ecosystem approach is already adopted. (author)

Ecophysiological adjustment of two Sphagnum species in response to anthropogenic nitrogen deposition.

Science.gov (United States)

Wiedermann, Magdalena M; Gunnarsson, Urban; Ericson, Lars; Nordin, Annika

2009-01-01

Here, it was investigated whether Sphagnum species have adjusted their nitrogen (N) uptake in response to the anthropogenic N deposition that has drastically altered N-limited ecosystems, including peatlands, worldwide. A lawn species, Sphagnum balticum, and a hummock species, Sphagnum fuscum, were collected from three peatlands along a gradient of N deposition (2, 8 and 12 kg N ha(-1) yr(-1)). The mosses were subjected to solutions containing a mixture of four N forms. In each solution one of these N forms was labeled with (15)N (namely (15)NH(+)(4), (15)NO(-)(3) and the amino acids [(15)N]alanine (Ala) and [(15)N]glutamic acid (Glu)). It was found that for both species most of the N taken up was from , followed by Ala, Glu, and very small amounts from NO(-)(3). At the highest N deposition site N uptake was reduced, but this did not prevent N accumulation as free amino acids in the Sphagnum tissues. The reduced N uptake may have been genetically selected for under the relatively short period with elevated N exposure from anthropogenic sources, or may have been the result of plasticity in the Sphagnum physiological response. The negligible Sphagnum NO(-)(3) uptake may make any NO(-)(3) deposited readily available to co-occurring vascular plants.

Litter drives ecosystem and plant community changes in cattail invasion.

Science.gov (United States)

Farrer, Emily C; Goldberg, Deborah E

2009-03-01

Invaded systems are commonly associated with a change in ecosystem processes and a decline in native species diversity; however, many different causal pathways linking invasion, ecosystem change, and native species decline could produce this pattern. The initial driver of environmental change may be anthropogenic, or it may be the invader itself; and the mechanism behind native species decline may be the human-induced environmental change, competition from the invader, or invader-induced environmental change (non-trophic effects). We examined applicability of each of these alternate pathways in Great Lakes coastal marshes invaded by hybrid cattail (Typha x glauca). In a survey including transects in three marshes, we found that T. x glauca was associated with locally high soil nutrients, low light, and large amounts of litter, and that native diversity was highest in areas of shallow litter depth. We tested whether live T. x glauca plants or their litter induced changes in the environment and in diversity with a live plant and litter transplant experiment. After one year, Typha litter increased soil NH4+ and N mineralization twofold, lowered light levels, and decreased the abundance and diversity of native plants, while live Typha plants had no effect on the environment or on native plants. This suggests that T. x glauca, through its litter production, can cause the changes in ecosystem processes that we commonly attribute to anthropogenic nutrient loading and that T. x glauca does not displace native species through competition for resources, but rather affects them non-trophically through its litter. Moreover, because T. x glauca plants were taller when grown with their own litter, we suggest that this invader may produce positive feedbacks and change the environment in ways that benefit itself and may promote its own invasion.

A case study of high Arctic anthropogenic disturbance to polar desert permafrost and ecosystems

Science.gov (United States)

Becker, M. S.; Pollard, W. H.

2013-12-01

One of the indirect impacts of climate change on Arctic ecosystems is the expected increase of industrial development in high latitudes. The scale of terrestrial impacts cannot be known ahead of time, particularly due to a lack of long-term impact studies in this region. With one of the slowest community recovery rates of any ecosystem, the high Artic biome will be under a considerable threat that is exacerbated by a high susceptibility to change in the permafrost thermal balance. One such area that provides a suitable location for study is an old airstrip near Eureka, Ellesmere Island, Nunavut (80.0175°N, 85.7340°W). While primarily used as an ice-runway for winter transport, the airstrip endured a yearly summer removal of vegetation that continued from 1947 until its abandonment in 1951. Since then, significant vegetative and geomorphic differences between disturbed and undisturbed areas have been noted in the literature throughout the decades (Bruggemann, 1953; Beschel, 1963; Couture and Pollard, 2007), but no system wide assessment of both the ecosystem and near-surface permafrost has been conducted. Key to our study is that the greatest apparent geomorphic and vegetative changes have occurred and persisted in areas where underlying ice-wedges have been disturbed. This suggests that the colonizing communities rapidly filled new available thermokarst niches and have produced an alternative ice-wedge stable state than the surrounding polar desert. We hypothesize that disturbed areas will currently have greater depths of thaw (deeper active layers) and degraded ice-wedges, with decreased vegetation diversity but higher abundance due to a changed hydrological balance. To test this a comprehensive set of near-surface active layer and ecosystem measurements were conducted. Permafrost dynamics were characterized using probing and high-frequency Ground Penetrating Radar (500 MHz) to map the near-surface details of ice-wedges and active layer. Vegetation was measured

Radionuclide behaviour in a coniferous woodland ecosystem in Cumbria, UK

International Nuclear Information System (INIS)

Jones, S.R.; Copplestone, D.; Johnson, M.S.

1996-01-01

The behaviour of 134Cs, 137Cs, 238Pu, 239+240Pu and 241Am, in food chains in a semi-natural woodland has been investigated and doses to the ecosystem due to the presence of these radionuclides of anthropogenic origin have been assessed. The woodland is located within 1 km of the coastal British Nuclear Fuels plc (BNFL) reprocessing plant at Sellafield, Cumbria (O.S. Grid Reference: NY 037045) and has received an input of radionuclides primarily through atmospheric discharges from the Sellafield site throughout its operational history of more than 40 years. Deposition has been enhanced by interception by the canopy, such that deposits in the woodland are significantly higher than adjacent pasture land. Within the wood, deposition is greatest along the front (or leading) edge in relation to aerosols transported to the woodland from Sellafield, due to the 'edge effect'. Despite the high radionuclide deposits, relatively low uptake and mobility within the ecosystem was observed. Estimated doses to the ecosystem at around 2 mGy a -1 , were dominated by external irradiation and were well below the levels thought to be necessary to harm terrestrial ecosystems. A provisional conclusion at this stage is that the measures taken to control emissions from Sellafield in line with radiological protection standards for humans have also been adequate to protect this potentially vulnerable ecosystem

Cascading elastic perturbation in Japan due to the 2012 M w 8.6 Indian Ocean earthquake.

Science.gov (United States)

Delorey, Andrew A; Chao, Kevin; Obara, Kazushige; Johnson, Paul A

2015-10-01

Since the discovery of extensive earthquake triggering occurring in response to the 1992 M w (moment magnitude) 7.3 Landers earthquake, it is now well established that seismic waves from earthquakes can trigger other earthquakes, tremor, slow slip, and pore pressure changes. Our contention is that earthquake triggering is one manifestation of a more widespread elastic disturbance that reveals information about Earth's stress state. Earth's stress state is central to our understanding of both natural and anthropogenic-induced crustal processes. We show that seismic waves from distant earthquakes may perturb stresses and frictional properties on faults and elastic moduli of the crust in cascading fashion. Transient dynamic stresses place crustal material into a metastable state during which the material recovers through a process termed slow dynamics. This observation of widespread, dynamically induced elastic perturbation, including systematic migration of offshore seismicity, strain transients, and velocity transients, presents a new characterization of Earth's elastic system that will advance our understanding of plate tectonics, seismicity, and seismic hazards.

Rare species support vulnerable functions in high-diversity ecosystems.

Science.gov (United States)

Mouillot, David; Bellwood, David R; Baraloto, Christopher; Chave, Jerome; Galzin, Rene; Harmelin-Vivien, Mireille; Kulbicki, Michel; Lavergne, Sebastien; Lavorel, Sandra; Mouquet, Nicolas; Paine, C E Timothy; Renaud, Julien; Thuiller, Wilfried

2013-01-01

spatial scales. As such, they are likely to insure against future uncertainty arising from climate change and the ever-increasing anthropogenic pressures on ecosystems. Our results call for a more detailed understanding of the role of rarity and functional vulnerability in ecosystem functioning.

[Seagrass ecosystems: contributions to and mechanisms of carbon sequestration].

Science.gov (United States)

Qiu, Guang-Long; Lin, Hsing-Juh; Li, Zong-Shan; Fan, Hang-Qing; Zhou, Hao-Lang; Liu, Guo-Hua

2014-06-01

The ocean's vegetated habitats, in particular seagrasses, mangroves and salt marshes, each capture and store a comparable amount of carbon per year, forming the Earth's blue carbon sinks, the most intense carbon sinks on the planet. Seagrass meadows, characterized by high primary productivity, efficient water column filtration and sediment stability, have a pronounced capacity for carbon sequestration. This is enhanced by low decomposition rates in anaerobic seagrass sediments. The carbon captured by seagrass meadows contributes significantly to the total blue carbon. At a global scale, seagrass ecosystems are carbon sink hot spots and have profound influences on the global carbon cycle. This importance combined with the many other functions of seagrass meadows places them among the most valuable ecosystems in the world. Unfortunately, seagrasses are declining globally at an alarming rate owing to anthropogenic disturbances and climate change, making them also among the most threatened ecosystems on the Earth. The role of coastal systems in carbon sequestration has received far too little attention and thus there are still many uncertainties in evaluating carbon sequestration of global seagrass meadows accurately. To better assess the carbon sequestration of global seagrass ecosystems, a number of scientific issues should be considered with high priorities: 1) more accurate measurements of seagrass coverage at national and global levels; 2) more comprehensive research into species- and location-specific carbon sequestration efficiencies; 3) in-depth exploration of the effects of human disturbance and global climate change on carbon capture and storage by seagrass ecosystems.

Mercury in Nordic ecosystems

Energy Technology Data Exchange (ETDEWEB)

Munthe, John; Waengberg, Ingvar (IVL Swedish Environmental Research Inst., Stockholm (SE)); Rognerud, Sigurd; Fjeld, Eirik (Norwegian Inst. for Water Research (NIVA), Oslo (Norway)); Verta, Matti; Porvari, Petri (Finnish Environment Inst. (SYKE), Helsinki (Finland)); Meili, Markus (Inst. of Applied Environmental Research (ITM), Stockholm (Sweden))

2007-12-15

This report provides a first comprehensive compilation and assessment of available data on mercury in air, precipitation, sediments and fish in the Nordic countries. The main conclusion is that mercury levels in Nordic ecosystems continue to be affected by long-range atmospheric transport. The geographical patterns of mercury concentrations in both sediments and fish are also strongly affected by ecosystem characteristics and in some regions possibly by historical pollution. An evaluation of geographical variations in mercury concentrations in precipitation indicates that the influence from anthropogenic sources from Central European areas is still significant. The annual variability of deposition is large and dependant of precipitation amounts. An evaluation of data from stations around the North Sea has indicated a significant decrease in mercury concentrations in precipitation indicating a continuous decrease of emissions in Europe (Waengberg et al., 2007). For mercury in air (TGM), the geographical pattern is less pronounced indicating the influence of mercury emissions and distribution over a larger geographical area (i.e. hemispherical transport). Comparison of recent (surficial) and historical lake sediments show significantly elevated concentrations of mercury most likely caused by anthropogenic atmospheric deposition over the past century. The highest pollution impact was observed in the coastal areas of southern Norway, in south western Finland and in Sweden from the coastal areas in the southwest across the central parts to the north-east. The general increase in recent versus old sediments was 2-5 fold. Data on mercury in Nordic freshwater fish was assembled and evaluated with respect to geographical variations. The fish data were further compared with temporal and spatial trends in mercury deposition and mercury contamination of lake sediments in order to investigate the coupling between atmospheric transport and deposition of mercury and local mercury

Impacts of climate change on biodiversity, ecosystems, and ecosystem services: technical input to the 2013 National Climate Assessment

Science.gov (United States)

Staudinger, Michelle D.; Grimm, Nancy B.; Staudt, Amanda; Carter, Shawn L.; Stuart, F. Stuart; Kareiva, Peter; Ruckelshaus, Mary; Stein, Bruce A.

2012-01-01

Ecosystems, and the biodiversity and services they support, are intrinsically dependent on climate. During the twentieth century, climate change has had documented impacts on ecological systems, and impacts are expected to increase as climate change continues and perhaps even accelerates. This technical input to the National Climate Assessment synthesizes our scientific understanding of the way climate change is affecting biodiversity, ecosystems, ecosystem services, and what strategies might be employed to decrease current and future risks. Building on past assessments of how climate change and other stressors are affecting ecosystems in the United States and around the world, we approach the subject from several different perspectives. First, we review the observed and projected impacts on biodiversity, with a focus on genes, species, and assemblages of species. Next, we examine how climate change is affecting ecosystem structural elements—such as biomass, architecture, and heterogeneity—and functions—specifically, as related to the fluxes of energy and matter. People experience climate change impacts on biodiversity and ecosystems as changes in ecosystem services; people depend on ecosystems for resources that are harvested, their role in regulating the movement of materials and disturbances, and their recreational, cultural, and aesthetic value. Thus, we review newly emerging research to determine how human activities and a changing climate are likely to alter the delivery of these ecosystem services. This technical input also examines two cross-cutting topics. First, we recognize that climate change is happening against the backdrop of a wide range of other environmental and anthropogenic stressors, many of which have caused dramatic ecosystem degradation already. This broader range of stressors interacts with climate change, and complicates our abilities to predict and manage the impacts on biodiversity, ecosystems, and the services they support. The

Biodiversity and its informative value in evaluation of localities under anthropogenic stress

International Nuclear Information System (INIS)

Dusek, L.; Jarkovsky, J.; Hodovsky, J.; Zahradkova, S.; Brabec, K.; Gelnar, M.; Andel, P.

2003-01-01

Biomonitoring of aquatic and terrestrial ecosystems became a frequent and valuable approach that is widely recognized as a necessary supplement to still more standard chemical monitoring programmes. Biomonitoring implies bioindication of changes that are routinely viewed as negative changes in biological systems due to the influence of stress factors, mostly of anthropogenic origin. Although there are an increasing number of scientific papers devoted to bioindication at the level of individual species or individual specimen (toxicity and genotoxicity testing, biomarkers etc.), complex biomonitoring at the ecosystem level seems to be rather difficult to manage and interpret. Although biodiversity is one of the central themes of ecology and ecotoxicology as well, there is still considerable disagreement in methodology of its comprehensive evaluation. Here we are presenting several approaches to biodiversity evaluation and results interpretation. Conclusions on methodology and interpretation are made on two sets of data - fish parasites under different environmental conditions and a lichen community under emission loading. We can conclude that biodiversity (community composition and structure) analysis could be used for: i) Retrospective bioindication, where it represents indication of complex changes, sensitive early warning, and indication with long-term memory, and/ or ii) prospective assessment, where it represents ecosystem health and stability. Best results are obtained when the biological community is stratified in order to reach environmentally reasonable units; and, these bioindicative components of the community are necessary for effective monitoring plans or ecological risk assessment studies. (authors)

Heterophil/Lymphocyte Alterations as a Measure of Stress in American Alligators in Relation to Anthropogenic Disturbance in a Louisiana Intermediate Marsh

Directory of Open Access Journals (Sweden)

Christopher M. Murray

2015-05-01

Full Text Available Numerous anthropogenic factors represent environmental threats to Gulf Coast wetland ecosystems and associated fauna. American alligators (Alligator mississippiensis have been subject to long-term management and used as ecological and physiological indicators of habitat quality in response to anthropogenic events and stochastic natural disasters. The present study monitored heterophil to lymphocyte ratios (an indicator of stress, in American alligators in a Louisiana intermediate marsh from 2009 to 2011, a time period that coincides with an oil inundation event that occurred in 2011. Sixteen alligators were observed and processed morphometrically (total length, snout-vent length and body mass. Heterophil to lymphocyte ratios were negatively correlated with size, suggesting larger American alligators were physiologically more resilient to the disturbance, more able to actively avoid these poor conditions, or are less affected by localized disturbance.

Estimating animal mortality from anthropogenic hazards

Science.gov (United States)

Carcass searches are a common method for studying the risk of anthropogenic hazards to wildlife, including non-target poisoning and collisions with anthropogenic structures. Typically, numbers of carcasses found must be corrected for scavenging rates and imperfect detection. Para...

δ15N as a proxy for historic anthropogenic nitrogen loading in Charleston Harbor, SC, USA

Science.gov (United States)

Payne, T. N.; Andrus, C. F. T.

2015-12-01

Bivalve shell geochemistry can serve as a useful indicator of changes in coastal environments. There is increasing interest in developing paleoenvironmental proxies from mollusk shell organic components. Numerous studies have focused on how the δ15N obtained from bivalve tissues can be used to trace present-day wastewater input into estuaries. However, comparatively little attention has been paid to tracing the impact of anthropogenic nitrogen loading into estuaries over time. By measuring historic levels of δ15N in the organic fraction of oyster shells (Crassostrea virginica) from archaeological sites around Charleston Harbor and comparing those levels to the δ15N content of modern shells, it is possible to assess how nitrogen has fluctuated historically in the area. Whole-shell samples from the Late Archaic Period (~3000-4000 BP, Late Woodland Period (~1400-800 BP), 18th and 19th centuries, and modern controls were measured for %N and d15N. Evidence of increased anthropogenic input of N is expected to begin in the early historic period based on similar analysis in Chesapeake Bay. More ancient samples may give insight into baseline conditions prior to recent population growth and industrialization. This information could help understand how large-scale anthropogenic nitrogen loading has affected coastal ecosystems over time and guide future remediation. Furthermore, this project will help refine and improve this novel proxy of past environmental conditions.

Heavy metal pollution characteristics of surface sediments in different aquatic ecosystems in eastern China: a comprehensive understanding.

Directory of Open Access Journals (Sweden)

Wenzhong Tang

Full Text Available Aquatic ecosystems in eastern China are suffering threats from heavy metal pollution because of rapid economic development and urbanization. Heavy metals in surface sediments were determined in five different aquatic ecosystems (river, reservoir, estuary, lake, and wetland ecosystems. The average Cd, Cr, Cu, Ni, Pb, and Zn concentrations were 0.716, 118, 37.3, 32.7, 56.6, and 204 mg/kg, respectively, and the higher concentrations were mainly found in sediment samples from river ecosystems. Cd was the most anthropogenically enriched pollutant, followed by Zn and Pb, indicated by enrichment factors >1.5. According to consensus-based sediment quality guidelines, potential ecological risk indices, and risk assessment codes, all five types of aquatic ecosystems were found to be polluted with heavy metals, and the most polluted ecosystems were mainly rivers. Cd was the most serious pollutant in all five aquatic ecosystems, and it was mainly found in the exchangeable fraction (about 30% of the total Cd concentration, on average. The results indicate that heavy metal contamination, especially of Cd, in aquatic ecosystems in eastern China should be taken into account in the development of management strategies for protecting the aquatic environment.

Effect of long-term mechanical perturbation on intertidal soft-bottom meiofaunal community spatial structure

Science.gov (United States)

Boldina, Inna; Beninger, Peter G.; Le Coz, Maïwen

2014-01-01

Situated at the interface of the microbial and macrofaunal compartments, soft-bottom meiofauna accomplish important ecological functions. However, little is known of their spatial distribution in the benthic environment. To assess the effects of long-term mechanical disturbance on soft-bottom meiofaunal spatial distribution, we compared a site subjected to long-term clam digging to a nearby site untouched by such activities, in Bourgneuf Bay, on the Atlantic coast of France. Six patterned replicate samples were taken at 3, 6, 9, 12, 15, 18, 21 and 24 cm lags, all sampling stations being separated by 5 m. A combined correlogram-variogram approach was used to enhance interpretation of the meiofaunal spatial distribution; in particular, the definition of autocorrelation strength and its statistical significance, as well as the detailed characteristics of the periodic spatial structure of nematode assemblages, and the determination of the maximum distance of their spatial autocorrelation. At both sites, nematodes and copepods clearly exhibited aggregated spatial structure at the meso scale; this structure was attenuated at the impacted site. The nematode spatial distribution showed periodicity at the non-impacted site, but not at the impacted site. This is the first explicit report of a periodic process in meiofaunal spatial distribution. No such cyclic spatial process was observed for the more motile copepods at either site. This first study to indicate the impacts of long-term anthropogenic mechanical perturbation on meiofaunal spatial structure opens the door to a new dimension of mudflat ecology. Since macrofaunal predator search behaviour is known to be strongly influenced by prey spatial structure, the alteration of this structure may have important consequences for ecosystem functioning.

Microbial Functional Gene Diversity Predicts Groundwater Contamination and Ecosystem Functioning

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Zhili He

2018-02-01

Full Text Available Contamination from anthropogenic activities has significantly impacted Earth’s biosphere. However, knowledge about how environmental contamination affects the biodiversity of groundwater microbiomes and ecosystem functioning remains very limited. Here, we used a comprehensive functional gene array to analyze groundwater microbiomes from 69 wells at the Oak Ridge Field Research Center (Oak Ridge, TN, representing a wide pH range and uranium, nitrate, and other contaminants. We hypothesized that the functional diversity of groundwater microbiomes would decrease as environmental contamination (e.g., uranium or nitrate increased or at low or high pH, while some specific populations capable of utilizing or resistant to those contaminants would increase, and thus, such key microbial functional genes and/or populations could be used to predict groundwater contamination and ecosystem functioning. Our results indicated that functional richness/diversity decreased as uranium (but not nitrate increased in groundwater. In addition, about 5.9% of specific key functional populations targeted by a comprehensive functional gene array (GeoChip 5 increased significantly (P < 0.05 as uranium or nitrate increased, and their changes could be used to successfully predict uranium and nitrate contamination and ecosystem functioning. This study indicates great potential for using microbial functional genes to predict environmental contamination and ecosystem functioning.

Life around the North Water ecosystem: Natural and social drivers of change over a millennium.

Science.gov (United States)

Hastrup, Kirsten; Andersen, Astrid Oberborbeck; Grønnow, Bjarne; Heide-Jørgensen, Mads Peter

2018-04-01

The formation of the North Water in Smith Sound about 4500 years ago, as evidenced by the establishment of bird colonies and human presence, also initiated a long-term anthropogenic agent as part of this High Arctic ecosystem. Different epochs have influenced the human occupation in the area: immigration pulses from Canada and Alaska, trade with meteorite iron throughout the Arctic, introduction of new technologies by whalers and explorers, exploitation of resources by foreigners, political sequestration, export of fox and seal skins and later narwhal products, and recently fishing. Physical drivers in terms of weather and climate affecting the northern hemisphere also impact accessibility and productivity of the ecosystem, with cascading effects on social drivers, again acting back on the natural ecologies. Despite its apparent isolation, the ecosystem had and still has wide ranging spatial ramifications that extend beyond the High Arctic, and include human activity. The challenge is to determine what is internal and what is external to an ecosystem.

Ecosystem heterogeneity determines the ecological resilience of the Amazon to climate change.

Science.gov (United States)

Levine, Naomi M; Zhang, Ke; Longo, Marcos; Baccini, Alessandro; Phillips, Oliver L; Lewis, Simon L; Alvarez-Dávila, Esteban; Segalin de Andrade, Ana Cristina; Brienen, Roel J W; Erwin, Terry L; Feldpausch, Ted R; Monteagudo Mendoza, Abel Lorenzo; Nuñez Vargas, Percy; Prieto, Adriana; Silva-Espejo, Javier Eduardo; Malhi, Yadvinder; Moorcroft, Paul R

2016-01-19

Amazon forests, which store ∼ 50% of tropical forest carbon and play a vital role in global water, energy, and carbon cycling, are predicted to experience both longer and more intense dry seasons by the end of the 21st century. However, the climate sensitivity of this ecosystem remains uncertain: several studies have predicted large-scale die-back of the Amazon, whereas several more recent studies predict that the biome will remain largely intact. Combining remote-sensing and ground-based observations with a size- and age-structured terrestrial ecosystem model, we explore the sensitivity and ecological resilience of these forests to changes in climate. We demonstrate that water stress operating at the scale of individual plants, combined with spatial variation in soil texture, explains observed patterns of variation in ecosystem biomass, composition, and dynamics across the region, and strongly influences the ecosystem's resilience to changes in dry season length. Specifically, our analysis suggests that in contrast to existing predictions of either stability or catastrophic biomass loss, the Amazon forest's response to a drying regional climate is likely to be an immediate, graded, heterogeneous transition from high-biomass moist forests to transitional dry forests and woody savannah-like states. Fire, logging, and other anthropogenic disturbances may, however, exacerbate these climate change-induced ecosystem transitions.

Aquatic subsidies transport anthropogenic nitrogen to riparian spiders

Energy Technology Data Exchange (ETDEWEB)

Akamatsu, Fumikazu, E-mail: f-akamt55@pwri.go.jp [Department of Environmental Sciences, Shinshu University, 3-1-1 Asahi, Matsumoto, Nagano 390-8621 (Japan); Toda, Hideshige [Department of Environmental Sciences, Shinshu University, 3-1-1 Asahi, Matsumoto, Nagano 390-8621 (Japan)

2011-05-15

Stable nitrogen isotopic composition ({delta}{sup 15}N) of aquatic biota increases with anthropogenic N inputs such as sewage and livestock waste downstream. Increase in {delta}{sup 15}N of riparian spiders downstream may reflect the anthropogenic pollution exposure through predation on aquatic insects. A two-source mixing model based on stable carbon isotopic composition showed the greatest dependence on aquatic insects (84%) by horizontal web-building spiders, followed by intermediate (48%) and low (31%) dependence by cursorial and vertical web-building spiders, respectively. The spider body size was negatively correlated with the dietary proportion of aquatic insects and spider {delta}{sup 15}N. The aquatic subsidies transported anthropogenic N to smaller riparian spiders downstream. This transport of anthropogenic N was regulated by spider's guild designation and body size. - Highlights: > {delta}{sup 15}N of aquatic insects increases downstream with anthropogenic nitrogen inputs. > {delta}{sup 15}N of riparian spiders increases with a high dietary proportion of aquatic insects and smaller spider body size. > The aquatic subsidies transport anthropogenic nitrogen to smaller riparian spiders downstream. - Smaller spiders assimilate anthropogenic nitrogen through the predation on aquatic subsides.

Aquatic subsidies transport anthropogenic nitrogen to riparian spiders

International Nuclear Information System (INIS)

Akamatsu, Fumikazu; Toda, Hideshige

2011-01-01

Stable nitrogen isotopic composition (δ 15 N) of aquatic biota increases with anthropogenic N inputs such as sewage and livestock waste downstream. Increase in δ 15 N of riparian spiders downstream may reflect the anthropogenic pollution exposure through predation on aquatic insects. A two-source mixing model based on stable carbon isotopic composition showed the greatest dependence on aquatic insects (84%) by horizontal web-building spiders, followed by intermediate (48%) and low (31%) dependence by cursorial and vertical web-building spiders, respectively. The spider body size was negatively correlated with the dietary proportion of aquatic insects and spider δ 15 N. The aquatic subsidies transported anthropogenic N to smaller riparian spiders downstream. This transport of anthropogenic N was regulated by spider's guild designation and body size. - Highlights: → δ 15 N of aquatic insects increases downstream with anthropogenic nitrogen inputs. → δ 15 N of riparian spiders increases with a high dietary proportion of aquatic insects and smaller spider body size. → The aquatic subsidies transport anthropogenic nitrogen to smaller riparian spiders downstream. - Smaller spiders assimilate anthropogenic nitrogen through the predation on aquatic subsides.

Perturbed effects at radiation physics

International Nuclear Information System (INIS)

Külahcı, Fatih; Şen, Zekâi

2013-01-01

Perturbation methodology is applied in order to assess the linear attenuation coefficient, mass attenuation coefficient and cross-section behavior with random components in the basic variables such as the radiation amounts frequently used in the radiation physics and chemistry. Additionally, layer attenuation coefficient (LAC) and perturbed LAC (PLAC) are proposed for different contact materials. Perturbation methodology provides opportunity to obtain results with random deviations from the average behavior of each variable that enters the whole mathematical expression. The basic photon intensity variation expression as the inverse exponential power law (as Beer–Lambert's law) is adopted for perturbation method exposition. Perturbed results are presented not only in terms of the mean but additionally the standard deviation and the correlation coefficients. Such perturbation expressions provide one to assess small random variability in basic variables. - Highlights: • Perturbation methodology is applied to Radiation Physics. • Layer attenuation coefficient (LAC) and perturbed LAC are proposed for contact materials. • Perturbed linear attenuation coefficient is proposed. • Perturbed mass attenuation coefficient (PMAC) is proposed. • Perturbed cross-section is proposed

Effectiveness of marine protected areas in managing the drivers of ecosystem change: a case of Mnazi Bay Marine Park, Tanzania.

Science.gov (United States)

Machumu, Milali Ernest; Yakupitiyage, Amararatne

2013-04-01

Marine protected areas (MPAs) are being promoted in Tanzania to mitigate the drivers of ecosystem change such as overfishing and other anthropogenic impacts on marine resources. The effectiveness of MPAs in managing those drivers was assessed in three ecological zones, seafront, mangrove, and riverine of Mnazi Bay Marine Park, using Participatory Community Analysis techniques, questionnaire survey, checklist and fishery resource assessment methods. Eleven major drivers of ecosystem change were identified. Resource dependence had a major effect in all ecological zones of the park. The results indicated that the park's legislations/regulations, management procedures, and conservation efforts are reasonably effective in managing its resources. The positive signs accrued from conservation efforts have been realized by the communities in terms of increased catch/income, awareness and compliance. However, some natural and anthropogenic drivers continued to threaten the park's sustainability. Furthermore, implementation of resource use and benefit sharing mechanisms still remained a considerable challenge to be addressed.

Carbon stocks and greenhouse gas balance of an old-growth forest and an anthropogenic peatland in southern Chile

Science.gov (United States)

Perez-Quezada, J. F.; Brito, C. E.; Valdés, A.; Urrutia, P.

2016-12-01

Few studies have reported the effects of deforestation on carbon stocks and greenhouse gas balance in the temperate forests of the southern hemisphere. In some areas of southern Chile, after clear-cut or forest fires occurs a proliferation of Sphagnum moss, generating an anthropogenic type of peatland. We measured the effects of this change on the carbon stocks and the greenhouse gas balance, starting in 2013. Carbon stocks were measured in >30 plots on each site; ecosystem CO2 fluxes were measured continuously using eddy covariance stations; CH4 and N2O fluxes were measured monthly using closed chambers and cavity ring-down spectroscopy technology. Total ecosystem carbon stock was 1,523 Mg ha-1 in the forest and 130 Mg ha-1 in the peatland, representing a 91% difference. Both land use types were found to act as sinks of CO2 (NEE=-1094.2 and -31.9 g CO2 m-2 year-¹ for the forest and peatland, respectively); CH4 was mainly captured in the forest and peatland soils, generating balances of -0.70 and -0.12 g CH₄ m-2 year-¹. N2O fluxes were extremely low, so were considered as null. These results indicate that the greenhouse gas balance moved from -1134.6 to -38.8 g CO2-eq m-2 year-1 when land use changed from forest to anthropogenic peatland. These results provide evidence of the importance of preserving old-growth forests in southern Chile.

Climate, carbon cycling, and deep-ocean ecosystems.

Science.gov (United States)

Smith, K L; Ruhl, H A; Bett, B J; Billett, D S M; Lampitt, R S; Kaufmann, R S

2009-11-17

Climate variation affects surface ocean processes and the production of organic carbon, which ultimately comprises the primary food supply to the deep-sea ecosystems that occupy approximately 60% of the Earth's surface. Warming trends in atmospheric and upper ocean temperatures, attributed to anthropogenic influence, have occurred over the past four decades. Changes in upper ocean temperature influence stratification and can affect the availability of nutrients for phytoplankton production. Global warming has been predicted to intensify stratification and reduce vertical mixing. Research also suggests that such reduced mixing will enhance variability in primary production and carbon export flux to the deep sea. The dependence of deep-sea communities on surface water production has raised important questions about how climate change will affect carbon cycling and deep-ocean ecosystem function. Recently, unprecedented time-series studies conducted over the past two decades in the North Pacific and the North Atlantic at >4,000-m depth have revealed unexpectedly large changes in deep-ocean ecosystems significantly correlated to climate-driven changes in the surface ocean that can impact the global carbon cycle. Climate-driven variation affects oceanic communities from surface waters to the much-overlooked deep sea and will have impacts on the global carbon cycle. Data from these two widely separated areas of the deep ocean provide compelling evidence that changes in climate can readily influence deep-sea processes. However, the limited geographic coverage of these existing time-series studies stresses the importance of developing a more global effort to monitor deep-sea ecosystems under modern conditions of rapidly changing climate.

Bacterial biodiversity-ecosystem functioning relations are modified by environmental complexity.

Science.gov (United States)

Langenheder, Silke; Bulling, Mark T; Solan, Martin; Prosser, James I

2010-05-26

With the recognition that environmental change resulting from anthropogenic activities is causing a global decline in biodiversity, much attention has been devoted to understanding how changes in biodiversity may alter levels of ecosystem functioning. Although environmental complexity has long been recognised as a major driving force in evolutionary processes, it has only recently been incorporated into biodiversity-ecosystem functioning investigations. Environmental complexity is expected to strengthen the positive effect of species richness on ecosystem functioning, mainly because it leads to stronger complementarity effects, such as resource partitioning and facilitative interactions among species when the number of available resource increases. Here we implemented an experiment to test the combined effect of species richness and environmental complexity, more specifically, resource richness on ecosystem functioning over time. We show, using all possible combinations of species within a bacterial community consisting of six species, and all possible combinations of three substrates, that diversity-functioning (metabolic activity) relationships change over time from linear to saturated. This was probably caused by a combination of limited complementarity effects and negative interactions among competing species as the experiment progressed. Even though species richness and resource richness both enhanced ecosystem functioning, they did so independently from each other. Instead there were complex interactions between particular species and substrate combinations. Our study shows clearly that both species richness and environmental complexity increase ecosystem functioning. The finding that there was no direct interaction between these two factors, but that instead rather complex interactions between combinations of certain species and resources underlie positive biodiversity ecosystem functioning relationships, suggests that detailed knowledge of how individual

Bacterial biodiversity-ecosystem functioning relations are modified by environmental complexity.

Directory of Open Access Journals (Sweden)

Silke Langenheder

Full Text Available BACKGROUND: With the recognition that environmental change resulting from anthropogenic activities is causing a global decline in biodiversity, much attention has been devoted to understanding how changes in biodiversity may alter levels of ecosystem functioning. Although environmental complexity has long been recognised as a major driving force in evolutionary processes, it has only recently been incorporated into biodiversity-ecosystem functioning investigations. Environmental complexity is expected to strengthen the positive effect of species richness on ecosystem functioning, mainly because it leads to stronger complementarity effects, such as resource partitioning and facilitative interactions among species when the number of available resource increases. METHODOLOGY/PRINCIPAL FINDINGS: Here we implemented an experiment to test the combined effect of species richness and environmental complexity, more specifically, resource richness on ecosystem functioning over time. We show, using all possible combinations of species within a bacterial community consisting of six species, and all possible combinations of three substrates, that diversity-functioning (metabolic activity relationships change over time from linear to saturated. This was probably caused by a combination of limited complementarity effects and negative interactions among competing species as the experiment progressed. Even though species richness and resource richness both enhanced ecosystem functioning, they did so independently from each other. Instead there were complex interactions between particular species and substrate combinations. CONCLUSIONS/SIGNIFICANCE: Our study shows clearly that both species richness and environmental complexity increase ecosystem functioning. The finding that there was no direct interaction between these two factors, but that instead rather complex interactions between combinations of certain species and resources underlie positive biodiversity

EnviroAtlas Connects Urban Ecosystem Services and Human ...

Science.gov (United States)

Ecosystem services in urban areas can improve public health and well-being by mitigating natural and anthropogenic pollution, and by promoting healthy lifestyles that include engagement with nature and enhanced opportunities for physical activity and social interaction. EPA’s EnviroAtlas online mapping tool identifies urban environmental features linked in the scientific and medical literature to specific aspects of public health and well-being. EnviroAtlas researchers have synthesized newly-generated one-meter resolution landcover data, downscaled census population data, and other existing datasets such as roads and parks. Resulting geospatial metrics represent health-related indicators of urban ecosystem services supply and demand by census block-group and finer scales. EnviroAtlas maps include percent of the population with limited window views of trees, tree cover along walkable roads, overall neighborhood green space, and proximity to parks. Demographic data can be overlaid to perform analyses of disproportionate distribution of urban ecosystem services across population groups. Together with the Eco-Health Relationship Browser, EnviroAtlas data can be linked to numerous aspects of public health and well-being including school performance, physical fitness, social capital, and longevity. EnviroAtlas maps have been developed using consistent methods to allow for comparisons between neighborhoods and across multiple U.S. communities. To feature eco-heal

Multidecadal change in streamflow associated with anthropogenic disturbances in the tropical Andes

Science.gov (United States)

Molina, A.; Vanacker, V.; Brisson, E.; Mora, D.; Balthazar, V.

2015-10-01

Andean headwater catchments are an important source of freshwater for downstream water users. However, few long-term studies exist on the relative importance of climate change and direct anthropogenic perturbations on flow regimes in these catchments. In this paper, we assess change in streamflow based on long time series of hydrometeorological data (1974-2008) and land cover reconstructions (1963-2009) in the Pangor catchment (282 km2) located in the tropical Andes. Three main land cover change trajectories can be distinguished during the period 1963-2009: (1) expansion of agricultural land by an area equal to 14 % of the catchment area (or 39 km2) in 46 years' time, (2) deforestation of native forests by 11 % (or -31 km2) corresponding to a mean rate of 67 ha yr-1, and (3) afforestation with exotic species in recent years by about 5 % (or 15 km2). Over the time period 1963-2009, about 50 % of the 64 km2 of native forests was cleared and converted to agricultural land. Given the strong temporal variability of precipitation and streamflow data related to El Niño-Southern Oscillation, we use empirical mode decomposition techniques to detrend the time series. The long-term increasing trend in rainfall is remarkably different from the observed changes in streamflow, which exhibit a decreasing trend. Hence, observed changes in streamflow are not the result of long-term change in precipitation but very likely result from anthropogenic disturbances associated with land cover change.

Megafauna of vulnerable marine ecosystems in French mediterranean submarine canyons: Spatial distribution and anthropogenic impacts

OpenAIRE

Fabri, Marie-claire; Pedel, Laura; Beuck, L.; Galgani, Francois; Hebbeln, D.; Freiwald, A.

2014-01-01

Vulnerable Marine Ecosystems (VME) in the deep Mediterranean Sea have been identified by the General Fisheries Commission for the Mediterranean as consisting of communities of Scleractinia (Lophelia pertusa and Madrepora oculata), Pennatulacea (Funiculina quadrangularis) and Alcyonacea (Isidella elongata). This paper deals with video data recorded in the heads of French Mediterranean canyons. Quantitative observations were extracted from 101 video films recorded during the MEDSEACAN cruise in...

Cascading elastic perturbation in Japan due to the 2012 Mw 8.6 Indian Ocean earthquake

Science.gov (United States)

Delorey, Andrew A.; Chao, Kevin; Obara, Kazushige; Johnson, Paul A.

2015-01-01

Since the discovery of extensive earthquake triggering occurring in response to the 1992 Mw (moment magnitude) 7.3 Landers earthquake, it is now well established that seismic waves from earthquakes can trigger other earthquakes, tremor, slow slip, and pore pressure changes. Our contention is that earthquake triggering is one manifestation of a more widespread elastic disturbance that reveals information about Earth’s stress state. Earth’s stress state is central to our understanding of both natural and anthropogenic-induced crustal processes. We show that seismic waves from distant earthquakes may perturb stresses and frictional properties on faults and elastic moduli of the crust in cascading fashion. Transient dynamic stresses place crustal material into a metastable state during which the material recovers through a process termed slow dynamics. This observation of widespread, dynamically induced elastic perturbation, including systematic migration of offshore seismicity, strain transients, and velocity transients, presents a new characterization of Earth’s elastic system that will advance our understanding of plate tectonics, seismicity, and seismic hazards. PMID:26601289

Restoring ecosystem functions and services by overcoming soil threats - The case of Mt. Hekla area in Iceland

Science.gov (United States)

Thorsson, Johann; Petursdottir, Thorunn

2015-04-01

Soils are one of the main fundamental bodies of terrestrial ecosystems. Soil functions contribute substantially to the ecosystem services humans and all other living beings depend on. Current soil threats are in most cases related to anthropogenic impacts and derived environmental pressures. For instance, overexploitation has in many cases damaged ecosystem resilience, affected current equilibrium and caused severe soil degradation. The resulting dysfunctional ecosystems are incapable of providing necessary ecosystem services. In such cases ecosystem restoration is necessary to restore ecosystem functions and ecological succession. The Mt. Hekla area in Iceland is an example of land suffering from accelerated erosion amplified by anthropogenic impacts. The area is 900 km2 located in South Iceland in the vicinity of the volcano Mt. Hekla. Today over 40% of the area is classified as eroded but historical documents indicate that vast part of the area were fertile and vegetated at the time of settlement, 1100 years ago; hence was able to withstand the geological disturbances occurring prior to the arrival of man as is obvious from the pristine woody patches still remaining. Severe soil degradation followed the large-scale deforestation and overgrazing that took place within the area. The initial land degradation event is considered to have occurred in the 11th century, but has been ongoing since then in several episodes. The Þjórsá glacial river flows through the area and carries enormous amounts of sediments every year. After the deforestation, the ecosystem resilience was damaged and the land left exposed to the elements. Eventually large scale wind erosion started, followed with water erosion and increased impact of freeze-thaw processes. The Soil Conservation Service of Iceland started working in the area in the early 20th century and land reclamation operations have been ongoing until this day. Considerable successes have been made as is manifested in the fact

Perturbative anyon gas

International Nuclear Information System (INIS)

Dasnieres de Veigy, A.; Ouvry, S.; Paris-6 Univ., 75

1992-06-01

The problem of the statistical mechanics of an anyon gas is addressed. A perturbative analysis in the anyonic coupling constant α is reviewed, and the thermodynamical potential is computed at first and second order. An adequate second quantized formalism (field theory at finite temperature) is proposed. At first order in perturbation theory, the results are strikingly simple: only the second virial coefficient close to bosonic statistics is corrected. At second order, however, the complexity of the anyon model appears. One can compute exactly the perturbative correction to each cluster coefficient. However, and contrary to first order, a closed expression for the equation of state seems out of reach. As an illustration, the perturbative expressions of a 3 , a 4 , a 5 and a 6 are given at second order. Finally, using the same formalism, the equation of state of an anyon gas in a constant magnetic field is analyzed at first order in perturbation theory. (K.A.) 16 refs.; 3 figs.; 7 tabs

Assessment of the fate of anthropogenic nitrogen in large watersheds by isotopic techniques

International Nuclear Information System (INIS)

Mayer, B.

1999-01-01

Human activity has greatly altered the nitrogen cycle in terrestrial and aquatic ecosystems and increased the nitrogen flow in many rivers. Preliminary work of the International SCOPE Nitrogen Project indicates that only 20% of the human-controlled nitrogen inputs to large watersheds are exported to the oceans in riverine flow (Howarth, 1998). Therefore, approximately 80% of the anthropogenic nitrogen inputs are either stored or denitrified in the catchments. Anthropogenic nitrogen can be retained in forests (possibly as a result of increased productivity) or in agricultural soils. It can also be stored in groundwater. These sinks are, however, often not large enough to account for the 'missing' nitrogen. It is, therefore, assumed that the majority of the human-controlled nitrogen inputs to large watersheds is denitrified in soils, riparian zones, wetlands, lakes, and rivers. Within the SCOPE Nitrogen Project, preliminary isotope analyses were performed on dissolved nitrates from several streams draining into the North Atlantic Ocean. Both δ 15 N nitrate and δ 18 O nitrate values were determined in order to identify nitrate sources. A further objective was to test, whether the isotopic composition of dissolved nitrate provides a measure for the extent to which denitrification occurs in the respective watersheds

Perturbation theory

International Nuclear Information System (INIS)

Bartlett, R.; Kirtman, B.; Davidson, E.R.

1978-01-01

After noting some advantages of using perturbation theory some of the various types are related on a chart and described, including many-body nonlinear summations, quartic force-field fit for geometry, fourth-order correlation approximations, and a survey of some recent work. Alternative initial approximations in perturbation theory are also discussed. 25 references

Relation between natural and anthropogenic factors in the redistribution of radionuclides on the 30 km Chernobyl NPP territory, including the result of countermeasures

International Nuclear Information System (INIS)

Kazakov, S.V.; Sukhoruchkin, A.K.; Arkhipov, N.P.; Arkhipov, A.N.; Loginova, L.S.; Meshalkin, G.S.

1997-01-01

Before the accident natural and anthropogenic ecosystems occupied about 90% of 30-km zone area, including 36% of forest ecosystem, ploughed lands -28%, meadows and bogs - 18%. About 10% of total areas were occupied by ameliorated lands, separate water reservoirs - 2.8% relatively large area. Ten years after the Chernobyl accident the lands structure was changed: Areas of forest territories became larger (up to 12-13%). Areas of territories occupied by different technical constructions, roads were increased too. Contamination of different objects of 30-km zone territory is very uneven, for instance variation of 137 Cs contamination of soil reaches the same thousand times (From 0.1-5 up to 10000 and more Ci/km 2 )

Using the CARDAMOM framework to retrieve global terrestrial ecosystem functioning properties

Science.gov (United States)

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

2016-04-01

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

Environmental science and vulnerable ecosystems. Programme and abstract book

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-11-01

The Society of Environmental Toxicology and Chemistry (SETAC) is a non-profit, professional society established to provide a multi-disciplinary forum for individuals and institutions engaged in the study of environmental problems. SETAC provides a vehicle for scientists to exchange information and share opinions across borders and across disciplines. It does so by organizing international and national meetings, workshops and symposia, by publishing a scientific journal, newsletter and books. There were 228 papers and 291 posters presented by more than 1000 contributors on aqueous and terrestrial ecosystems and their vulnerability to anthropogenic pollution and contamination. (EG)

Environmental science and vulnerable ecosystems. Programme and abstract book

International Nuclear Information System (INIS)

1995-01-01

The Society of Environmental Toxicology and Chemistry (SETAC) is a non-profit, professional society established to provide a multi-disciplinary forum for individuals and institutions engaged in the study of environmental problems. SETAC provides a vehicle for scientists to exchange information and share opinions across border and across disciplines. It does so by organizing international and national meetings, workshops and symposia, by publishing a scientific journal, newsletter and books. There were 228 papers and 291 posters presented by more than 1000 contributors on aqueous and terrestrial ecosystems and their vulnerability to anthropogenic pollution and contamination. (EG)

Anthropogenic Space Weather

Science.gov (United States)

Gombosi, T. I.; Baker, D. N.; Balogh, A.; Erickson, P. J.; Huba, J. D.; Lanzerotti, L. J.

2017-11-01

Anthropogenic effects on the space environment started in the late 19th century and reached their peak in the 1960s when high-altitude nuclear explosions were carried out by the USA and the Soviet Union. These explosions created artificial radiation belts near Earth that resulted in major damages to several satellites. Another, unexpected impact of the high-altitude nuclear tests was the electromagnetic pulse (EMP) that can have devastating effects over a large geographic area (as large as the continental United States). Other anthropogenic impacts on the space environment include chemical release experiments, high-frequency wave heating of the ionosphere and the interaction of VLF waves with the radiation belts. This paper reviews the fundamental physical process behind these phenomena and discusses the observations of their impacts.

Ecosystem services in European protected areas: Ambiguity in the views of scientists and managers?

Directory of Open Access Journals (Sweden)

Christiaan Hummel

Full Text Available Protected Areas are a key component of nature conservation. They can play an important role in counterbalancing the impacts of ecosystem degradation. For an optimal protection of a Protected Area it is essential to account for the variables underlying the major Ecosystem Services an area delivers, and the threats upon them. Here we show that the perception of these important variables differs markedly between scientists and managers of Protected Areas in mountains and transitional waters. Scientists emphasise variables of abiotic and biotic nature, whereas managers highlight socio-economic, cultural and anthropogenic variables. This indicates fundamental differences in perception. To be able to better protect an area it would be advisable to bring the perception of scientists and managers closer together. Intensified and harmonised communication across disciplinary and professional boundaries will be needed to implement and improve Ecosystem Service oriented management strategies in current and future Protected Areas.

Ecosystem services in European protected areas: Ambiguity in the views of scientists and managers?

Science.gov (United States)

Provenzale, Antonello; van der Meer, Jaap; Wijnhoven, Sander; Nolte, Arno; Poursanidis, Dimitris; Janss, Guyonne; Jurek, Matthias; Andresen, Magnus; Poulin, Brigitte; Kobler, Johannes; Beierkuhnlein, Carl; Honrado, João; Razinkovas, Arturas; Stritih, Ana; Bargmann, Tessa; Ziemba, Alex; Bonet-García, Francisco; Adamescu, Mihai Cristian; Janssen, Gerard; Hummel, Herman

2017-01-01

Protected Areas are a key component of nature conservation. They can play an important role in counterbalancing the impacts of ecosystem degradation. For an optimal protection of a Protected Area it is essential to account for the variables underlying the major Ecosystem Services an area delivers, and the threats upon them. Here we show that the perception of these important variables differs markedly between scientists and managers of Protected Areas in mountains and transitional waters. Scientists emphasise variables of abiotic and biotic nature, whereas managers highlight socio-economic, cultural and anthropogenic variables. This indicates fundamental differences in perception. To be able to better protect an area it would be advisable to bring the perception of scientists and managers closer together. Intensified and harmonised communication across disciplinary and professional boundaries will be needed to implement and improve Ecosystem Service oriented management strategies in current and future Protected Areas. PMID:29140983

Ecosystem services in European protected areas: Ambiguity in the views of scientists and managers?

Science.gov (United States)

Hummel, Christiaan; Provenzale, Antonello; van der Meer, Jaap; Wijnhoven, Sander; Nolte, Arno; Poursanidis, Dimitris; Janss, Guyonne; Jurek, Matthias; Andresen, Magnus; Poulin, Brigitte; Kobler, Johannes; Beierkuhnlein, Carl; Honrado, João; Razinkovas, Arturas; Stritih, Ana; Bargmann, Tessa; Ziemba, Alex; Bonet-García, Francisco; Adamescu, Mihai Cristian; Janssen, Gerard; Hummel, Herman

2017-01-01

Protected Areas are a key component of nature conservation. They can play an important role in counterbalancing the impacts of ecosystem degradation. For an optimal protection of a Protected Area it is essential to account for the variables underlying the major Ecosystem Services an area delivers, and the threats upon them. Here we show that the perception of these important variables differs markedly between scientists and managers of Protected Areas in mountains and transitional waters. Scientists emphasise variables of abiotic and biotic nature, whereas managers highlight socio-economic, cultural and anthropogenic variables. This indicates fundamental differences in perception. To be able to better protect an area it would be advisable to bring the perception of scientists and managers closer together. Intensified and harmonised communication across disciplinary and professional boundaries will be needed to implement and improve Ecosystem Service oriented management strategies in current and future Protected Areas.

Projected future climate change and Baltic Sea ecosystem management.

Science.gov (United States)

Andersson, Agneta; Meier, H E Markus; Ripszam, Matyas; Rowe, Owen; Wikner, Johan; Haglund, Peter; Eilola, Kari; Legrand, Catherine; Figueroa, Daniela; Paczkowska, Joanna; Lindehoff, Elin; Tysklind, Mats; Elmgren, Ragnar

2015-06-01

Climate change is likely to have large effects on the Baltic Sea ecosystem. Simulations indicate 2-4 °C warming and 50-80 % decrease in ice cover by 2100. Precipitation may increase ~30 % in the north, causing increased land runoff of allochthonous organic matter (AOM) and organic pollutants and decreased salinity. Coupled physical-biogeochemical models indicate that, in the south, bottom-water anoxia may spread, reducing cod recruitment and increasing sediment phosphorus release, thus promoting cyanobacterial blooms. In the north, heterotrophic bacteria will be favored by AOM, while phytoplankton production may be reduced. Extra trophic levels in the food web may increase energy losses and consequently reduce fish production. Future management of the Baltic Sea must consider the effects of climate change on the ecosystem dynamics and functions, as well as the effects of anthropogenic nutrient and pollutant load. Monitoring should have a holistic approach, encompassing both autotrophic (phytoplankton) and heterotrophic (e.g., bacterial) processes.

Nutrient cycling in salt marshes: An ecosystem service to reduce eutrophication

DEFF Research Database (Denmark)

Lillebø, A. I.; Sousa, A. I.; Flindt, M. R.

2013-01-01

and sequestration in salt marshes. This chapter will thus emphasise that salt marsh halophytes have a crucial role on nutrient cycling and sequestration, providing ecological services that contribute to maintain the ecosystem health. © 2012 Nova Science Publishers, Inc. All rights reserved.......Salt marshes are classified as sensitive habitat under the Habitats Directive (92/43/EEC), which aims to promote the maintenance of biodiversity. Worldwide, the reduction of salt marsh areas, as a result of anthropogenic disturbance is of major concern, and several studies on the ecology...

Integrated trend assessment of ecosystem changes in the Limfjord (Denmark): evidence of a recent regime shift?

DEFF Research Database (Denmark)

Tomczak, Maciej Tomasz; Dinesen, Grete E.; Hoffmann, Erik

2012-01-01

An integrated ecosystem assessment was carried out for the Limfjord over the period from 1984 to 2008 to describe changes in ecosystem structure and potentially important drivers. The Limfjord is an eutrophic transitional Danish fjord system with the main inflow from the North Sea in the west and...... further showed the regime shift to be driven by a combination of anthropogenic pressures and possible interplay with climatic disturbance......An integrated ecosystem assessment was carried out for the Limfjord over the period from 1984 to 2008 to describe changes in ecosystem structure and potentially important drivers. The Limfjord is an eutrophic transitional Danish fjord system with the main inflow from the North Sea in the west......), jellyfish, common shore crab, starfish and blue mussels. We interpret this change as a regime shift that showed a similar temporal pattern to regime shifts identified in adjacent seas. The observed changes in trophic interactions and food web reorganisation suggested a non-linear regime shift. The analyses...

Global Human Footprint on the Linkage between Biodiversity and Ecosystem Functioning in Reef Fishes

Science.gov (United States)

Mora, Camilo; Aburto-Oropeza, Octavio; Ayala Bocos, Arturo; Ayotte, Paula M.; Banks, Stuart; Bauman, Andrew G.; Beger, Maria; Bessudo, Sandra; Booth, David J.; Brokovich, Eran; Brooks, Andrew; Chabanet, Pascale; Cinner, Joshua E.; Cortés, Jorge; Cruz-Motta, Juan J.; Cupul Magaña, Amilcar; DeMartini, Edward E.; Edgar, Graham J.; Feary, David A.; Ferse, Sebastian C. A.; Friedlander, Alan M.; Gaston, Kevin J.; Gough, Charlotte; Graham, Nicholas A. J.; Green, Alison; Guzman, Hector; Hardt, Marah; Kulbicki, Michel; Letourneur, Yves; López Pérez, Andres; Loreau, Michel; Loya, Yossi; Martinez, Camilo; Mascareñas-Osorio, Ismael; Morove, Tau; Nadon, Marc-Olivier; Nakamura, Yohei; Paredes, Gustavo; Polunin, Nicholas V. C.; Pratchett, Morgan S.; Reyes Bonilla, Héctor; Rivera, Fernando; Sala, Enric; Sandin, Stuart A.; Soler, German; Stuart-Smith, Rick; Tessier, Emmanuel; Tittensor, Derek P.; Tupper, Mark; Usseglio, Paolo; Vigliola, Laurent; Wantiez, Laurent; Williams, Ivor; Wilson, Shaun K.; Zapata, Fernando A.

2011-01-01

Difficulties in scaling up theoretical and experimental results have raised controversy over the consequences of biodiversity loss for the functioning of natural ecosystems. Using a global survey of reef fish assemblages, we show that in contrast to previous theoretical and experimental studies, ecosystem functioning (as measured by standing biomass) scales in a non-saturating manner with biodiversity (as measured by species and functional richness) in this ecosystem. Our field study also shows a significant and negative interaction between human population density and biodiversity on ecosystem functioning (i.e., for the same human density there were larger reductions in standing biomass at more diverse reefs). Human effects were found to be related to fishing, coastal development, and land use stressors, and currently affect over 75% of the world's coral reefs. Our results indicate that the consequences of biodiversity loss in coral reefs have been considerably underestimated based on existing knowledge and that reef fish assemblages, particularly the most diverse, are greatly vulnerable to the expansion and intensity of anthropogenic stressors in coastal areas. PMID:21483714

Anthropogenic combustion iron as a complex climate forcer.

Science.gov (United States)

Matsui, Hitoshi; Mahowald, Natalie M; Moteki, Nobuhiro; Hamilton, Douglas S; Ohata, Sho; Yoshida, Atsushi; Koike, Makoto; Scanza, Rachel A; Flanner, Mark G

2018-04-23

Atmospheric iron affects the global carbon cycle by modulating ocean biogeochemistry through the deposition of soluble iron to the ocean. Iron emitted by anthropogenic (fossil fuel) combustion is a source of soluble iron that is currently considered less important than other soluble iron sources, such as mineral dust and biomass burning. Here we show that the atmospheric burden of anthropogenic combustion iron is 8 times greater than previous estimates by incorporating recent measurements of anthropogenic magnetite into a global aerosol model. This new estimation increases the total deposition flux of soluble iron to southern oceans (30-90 °S) by 52%, with a larger contribution of anthropogenic combustion iron than dust and biomass burning sources. The direct radiative forcing of anthropogenic magnetite is estimated to be 0.021 W m -2 globally and 0.22 W m -2 over East Asia. Our results demonstrate that anthropogenic combustion iron is a larger and more complex climate forcer than previously thought, and therefore plays a key role in the Earth system.

Meteorological and small scale internal ecosystem variability characterize the uncertainty of ecosystem level responses to elevated CO2. Insights from the Duke Forest FACE experiment

Science.gov (United States)

Paschalis, A.; Katul, G. G.; Fatichi, S.; Palmroth, S.; Way, D.

2017-12-01

One of the open questions in climate change research is the pathway by which elevated atmospheric CO2 concentration impacts the biogeochemical and hydrological cycles at the ecosystem scale. This impact leads to significant changes in long-term carbon stocks and the potential of ecosystems to sequester CO2, partially mitigating anthropogenic emissions. While the significance of elevated atmospheric CO2 concentration on instantaneous leaf-level processes such as photosynthesis and transpiration is rarely disputed, its integrated effect at the ecosystem level and at long-time scales remains a subject of debate. This debate has taken on some urgency as illustrated by differences arising between ecosystem modelling studies, and data-model comparisons using Free Air CO2 Enrichment (FACE) sites around the world. Inherent leaf-to-leaf variability in gas exchange rates can generate such inconsistencies. This inherent variability arises from the combined effect of meteorological "temporal" variability and the "spatial" variability of the biochemical parameters regulating vegetation carbon uptake. This combined variability leads to a non-straightforward scaling of ecosystem fluxes from the leaf to ecosystems. To illustrate this scaling behaviour, we used 10 years of leaf gas exchange measurements collected at the Duke Forest FACE experiment. The internal variability of the ecosystem parameters are first quantified and then combined with three different leaf-scale stomatal conductance models and an ecosystem model. The main results are: (a) Variability of the leaf level fluxes is dependent on both the meteorological drivers and differences in leaf age, position within the canopy, nitrogen and CO2 fertilization, which can be accommodated in model parameters; (b) Meteorological variability plays the dominant role at short temporal scales while parameter variability is significant at longer temporal scales. (c) Leaf level results do not necessarily translate to similar ecosystem

Potential effects of climate change on freshwater ecosystems of the New England/Mid-Atlantic Region

Science.gov (United States)

Moore, M.V.; Pace, M.L.; Mather, J.R.; Murdoch, Peter S.; Howarth, R.W.; Folt, C.L.; Chen, C.-Y.; Hemond, Harold F.; Flebbe, P.A.; Driscoll, C.T.

1997-01-01

Numerous freshwater ecosystems, dense concentrations of humans along the eastern seaboard, extensive forests and a history of intensive land use distinguish the New England/Mid-Atlantic Region. Human population densities are forecast to increase in portions of the region at the same time that climate is expected to be changing. Consequently, the effects of humans and climatic change are likely to affect freshwater ecosystems within the region interactively. The general climate, at present, is humid continental, and the region receives abundant precipitation. Climatic projections for a 2 ??CO2 atmosphere, however, suggest warmer and drier conditions for much of this region. Annual temperature increases ranging from 3-5??C are projected, with the greatest increases occurring in autumn or winter. According to a water balance model, the projected increase in temperature will result in greater rates of evaporation and evapotranspiration. This could cause a 21 and 31% reduction in annual stream flow in the southern and northern sections of the region, respectively, with greatest reductions occurring in autumn and winter. The amount and duration of snow cover is also projected to decrease across the region, and summer convective thunderstorms are likely to decrease in frequency but increase in intensity. The dual effects of climate change and direct anthropogenic stress will most likely alter hydrological and biogeochemical processes, and, hence, the floral and faunal communities of the region's freshwater ecosystems. For example, the projected increase in evapotranspiration and evaporation could eliminate most bog ecosystems, and increases in water temperature may increase bioaccumulation, and possibly biomagnification, of organic and inorganic contaminants. Not all change may be adverse. For example, a decrease in runoff may reduce the intensity of ongoing estuarine eutrophication, and acidification of aquatic habitats during the spring snowmelt period may be

The deforestation story: testing for anthropogenic origins of Africa's flammable grassy biomes.

Science.gov (United States)

Bond, William; Zaloumis, Nicholas P

2016-06-05

Africa has the most extensive C4 grassy biomes of any continent. They are highly flammable accounting for greater than 70% of the world's burnt area. Much of Africa's savannas and grasslands occur in climates warm enough and wet enough to support closed forests. The combination of open grassy systems and the frequent fires they support have long been interpreted as anthropogenic artefacts caused by humans igniting frequent fires. True grasslands, it was believed, would be restricted to climates too dry or too cold to support closed woody vegetation. The idea that higher-rainfall savannas are anthropogenic and that fires are of human origin has led to initiatives to 'reforest' Africa's open grassy systems paid for by carbon credits under the assumption that the net effect of converting these system to forests would sequester carbon, reduce greenhouse gases and mitigate global warming. This paper reviews evidence for the antiquity of African grassy ecosystems and for the fires that they sustain. Africa's grassy biomes and the fires that maintain them are ancient and there is no support for the idea that humans caused large-scale deforestation. Indicators of old-growth grasslands are described. These can help distinguish secondary grasslands suitable for reforestation from ancient grasslands that should not be afforested.This article is part of the themed issue 'The interaction of fire and mankind'. © 2016 The Author(s).

Influence of natural and anthropogenic factors on the distribution of xerothermic plants in the lower San river valley (SE Poland

Directory of Open Access Journals (Sweden)

Rafał Krawczyk

2012-12-01

Full Text Available The aim of the present study was to describe the distribution of xerothermic species of vascular plants in the lower San River valley and the relationship between their density and the intensity of selected environmental (natural and anthropogenic factors. Xerothermic species occurred more frequently in the present valley floor compared to the glacial terrace. Within the present valley, the highest density was observed in the floodplain. The examined species also occurred more often on steep slopes of the valley, at the margins of the present valley terraces, and in the area of occurrence of aeolian sands. Moreover, a positive correlation has been found between the number of xerothermic species and the area of polyhemeroby ecosystems. The distribution of xero- and thermophilous species is determined by natural edaphic and geomorphological factors as well as anthropogenic ones (land use, lowering of the groundwater level as a result of river regulation.

Developments in perturbation theory

International Nuclear Information System (INIS)

Greenspan, E.

1976-01-01

Included are sections dealing with perturbation expressions for reactivity, methods for the calculation of perturbed fluxes, integral transport theory formulations for reactivity, generalized perturbation theory, sensitivity and optimization studies, multigroup calculations of bilinear functionals, and solution of inhomogeneous Boltzmann equations with singular operators

PerturbationAnalyzer: a tool for investigating the effects of concentration perturbation on protein interaction networks.

Science.gov (United States)

Li, Fei; Li, Peng; Xu, Wenjian; Peng, Yuxing; Bo, Xiaochen; Wang, Shengqi

2010-01-15

The propagation of perturbations in protein concentration through a protein interaction network (PIN) can shed light on network dynamics and function. In order to facilitate this type of study, PerturbationAnalyzer, which is an open source plugin for Cytoscape, has been developed. PerturbationAnalyzer can be used in manual mode for simulating user-defined perturbations, as well as in batch mode for evaluating network robustness and identifying significant proteins that cause large propagation effects in the PINs when their concentrations are perturbed. Results from PerturbationAnalyzer can be represented in an intuitive and customizable way and can also be exported for further exploration. PerturbationAnalyzer has great potential in mining the design principles of protein networks, and may be a useful tool for identifying drug targets. PerturbationAnalyzer can be accessed from the Cytoscape web site http://www.cytoscape.org/plugins/index.php or http://biotech.bmi.ac.cn/PerturbationAnalyzer. Supplementary data are available at Bioinformatics online.

An invasive vector of zoonotic disease sustained by anthropogenic resources: the raccoon dog in northern Europe.

Directory of Open Access Journals (Sweden)

Karmen Süld

Full Text Available The raccoon dog (Nyctereutes procyonoides is an introduced species in Europe with a continually expanding range. Since the species is capable of affecting local ecosystems and is a vector for a number of severe zoonotic diseases, it is important to understand its food habits. Raccoon dog diet was studied in Estonia by examining the contents of 223 stomach samples collected during the coldest period of the year, August to March, in 2010-2012. The most frequently consumed food categories were anthropogenic plants (e.g. cereals, fruits; FO = 56.1% and carrion (e.g. carcasses of artiodactyls and carnivores; FO = 48.4%. Carrion was also the only food category that was consumed significantly more frequently by raccoon dogs exhibiting symptoms of sarcoptic mange than by uninfected animals. Small mammals, which represent intermediate hosts for the zoonotic tapeworm Echinococcus multilocularis, were more commonly recorded in samples also containing anthropogenic plants than expected by chance. Comparison of raccoon dog and red fox (Vulpes vulpes diet in Estonia revealed higher overlap than found elsewhere in Europe, with 'carrion' and 'anthropogenic plants' making up the bulk of both species' diet; however, raccoon dogs were more omnivorous than red foxes. Our results suggest that while the use of most food categories reflects the phenology of natural food sources, 'anthropogenic plants' and 'carrion' provide an essential resource for raccoon dogs during the coldest period of the year, with the latter resource especially important for individuals infected with sarcoptic mange. Since both of these food categories and small mammals are often found at supplementary feeding sites for wild boar (Sus scrofa, this game management practice may facilitate high densities of mesocarnivores and promote the spread of some severe zoonotic diseases, including alveolar echinococcosis, trichinellosis, rabies and sarcoptic mange.

An invasive vector of zoonotic disease sustained by anthropogenic resources: the raccoon dog in northern Europe.

Science.gov (United States)

Süld, Karmen; Valdmann, Harri; Laurimaa, Leidi; Soe, Egle; Davison, John; Saarma, Urmas

2014-01-01

The raccoon dog (Nyctereutes procyonoides) is an introduced species in Europe with a continually expanding range. Since the species is capable of affecting local ecosystems and is a vector for a number of severe zoonotic diseases, it is important to understand its food habits. Raccoon dog diet was studied in Estonia by examining the contents of 223 stomach samples collected during the coldest period of the year, August to March, in 2010-2012. The most frequently consumed food categories were anthropogenic plants (e.g. cereals, fruits; FO = 56.1%) and carrion (e.g. carcasses of artiodactyls and carnivores; FO = 48.4%). Carrion was also the only food category that was consumed significantly more frequently by raccoon dogs exhibiting symptoms of sarcoptic mange than by uninfected animals. Small mammals, which represent intermediate hosts for the zoonotic tapeworm Echinococcus multilocularis, were more commonly recorded in samples also containing anthropogenic plants than expected by chance. Comparison of raccoon dog and red fox (Vulpes vulpes) diet in Estonia revealed higher overlap than found elsewhere in Europe, with 'carrion' and 'anthropogenic plants' making up the bulk of both species' diet; however, raccoon dogs were more omnivorous than red foxes. Our results suggest that while the use of most food categories reflects the phenology of natural food sources, 'anthropogenic plants' and 'carrion' provide an essential resource for raccoon dogs during the coldest period of the year, with the latter resource especially important for individuals infected with sarcoptic mange. Since both of these food categories and small mammals are often found at supplementary feeding sites for wild boar (Sus scrofa), this game management practice may facilitate high densities of mesocarnivores and promote the spread of some severe zoonotic diseases, including alveolar echinococcosis, trichinellosis, rabies and sarcoptic mange.

Rare species support vulnerable functions in high-diversity ecosystems.

Directory of Open Access Journals (Sweden)

David Mouillot

ecosystems across spatial scales. As such, they are likely to insure against future uncertainty arising from climate change and the ever-increasing anthropogenic pressures on ecosystems. Our results call for a more detailed understanding of the role of rarity and functional vulnerability in ecosystem functioning.

Boreal forests can have a remarkable role in reducing greenhouse gas emissions locally: Land use-related and anthropogenic greenhouse gas emissions and sinks at the municipal level

Energy Technology Data Exchange (ETDEWEB)

Vanhala, Pekka, E-mail: pekka.vanhala@ymparisto.fi [Finnish Environment Institute, Natural Environment Centre, P.O. Box 140, Mechelininkatu 34 a, FI-00251 Helsinki (Finland); Bergström, Irina [Finnish Environment Institute, Natural Environment Centre, P.O. Box 140, Mechelininkatu 34 a, FI-00251 Helsinki (Finland); Haaspuro, Tiina [University of Helsinki, Department of Environmental Sciences, P.O. Box 65, Viikinkaari 1, 00014 Helsinki (Finland); Kortelainen, Pirkko; Holmberg, Maria; Forsius, Martin [Finnish Environment Institute, Natural Environment Centre, P.O. Box 140, Mechelininkatu 34 a, FI-00251 Helsinki (Finland)

2016-07-01

Ecosystem services have become an important concept in policy-making. Carbon (C) sequestration into ecosystems is a significant ecosystem service, whereas C losses can be considered as an ecosystem disservice. Municipalities are in a position to make decisions that affect local emissions and therefore are important when considering greenhouse gas (GHG) mitigation. Integrated estimations of fluxes at a regional level help local authorities to develop land use policies for minimising GHG emissions and maximising C sinks. In this study, the Finnish national GHG accounting system is modified and applied at the municipal level by combining emissions and sinks from agricultural land, forest areas, water bodies and mires (land use-related GHG emissions) with emissions from activities such as energy production and traffic (anthropogenic GHG emissions) into the LUONNIKAS calculation tool. The study area consists of 14 municipalities within the Vanajavesi catchment area located in Southern Finland. In these municipalities, croplands, peat extraction sites, water bodies and undrained mires are emission sources, whereas forests are large carbon sinks that turn the land use-related GHG budget negative, resulting in C sequestration into the ecosystem. The annual land use-related sink in the study area was 78 t CO{sub 2} eq km{sup −2} and 2.8 t CO{sub 2} eq per capita. Annual anthropogenic GHG emissions from the area amounted to 250 t CO{sub 2} eq km{sup −2} and 9.2 t CO{sub 2} eq per capita. Since forests are a significant carbon sink and the efficiency of this sink is heavily affected by forest management practices, forest management policy is a key contributing factor for mitigating municipal GHG emissions. - Highlights: • The significance of natural landscapes in the regional C budgets is shown. • Boreal forests can be remarkable C sinks enabling net C sequestration in ecosystems. • The large area of forest may compensate for all C emissions in the municipality. �

Measuring resilience of coupled human-water systems using ecosystem services compatible indicators

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Hannah, D. M.; Mao, F.; Karpouzoglou, T.; Clark, J.; Buytaert, W.

2017-12-01

To explore the dynamics of socio-hydrological systems under change, the concepts of resilience and ecosystem services serve as useful tools. In this context, resilience refers to the capacity of a socio-hydrological system to retain its structural and functional state despite perturbations, while ecosystem services offer a good proxy of the state that reflects human-water intersections. Efforts are needed to maintain and improve socio-hydrological resilience for future contingencies to secure hydrological ecosystem services supply. This requires holistic indicators of resilience for coupled human-water systems that are essential for quantitative assessment, change tracking, inter-case comparison, as well as resilience management. However, such indicators are still lacking. Our research aims to propose widely applicable resilience indicators that are suitable for the coupled human-water context, and compatible with ecosystem services. The existing resilience indicators for both eco-hydrological and socio-economic sectors are scrutinised, screened and analysed to build these new indicators. Using the proposed indicators, we compare the resilience and its temporal change among a set of example regions, and discusses the linkages between socio-hydrological resilience and hydrological ecosystem services with empirical cases.

Revealing turning points in ecosystem functioning over the Northern Eurasian agricultural frontier.

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Horion, Stéphanie; Prishchepov, Alexander V; Verbesselt, Jan; de Beurs, Kirsten; Tagesson, Torbern; Fensholt, Rasmus

2016-08-01

The collapse of the Soviet Union in 1991 has been a turning point in the World history that left a unique footprint on the Northern Eurasian ecosystems. Conducting large scale mapping of environmental change and separating between naturogenic and anthropogenic drivers is a difficult endeavor in such highly complex systems. In this research a piece-wise linear regression method was used for breakpoint detection in Rain-Use Efficiency (RUE) time series and a classification of ecosystem response types was produced. Supported by earth observation data, field data, and expert knowledge, this study provides empirical evidence regarding the occurrence of drastic changes in RUE (assessment of the timing, the direction and the significance of these changes) in Northern Eurasian ecosystems between 1982 and 2011. About 36% of the study area (3.4 million km(2) ) showed significant (P agricultural land abandonment. Our study also showed that recurrent droughts deeply affected vegetation productivity throughout the observation period, with a general worsening of the drought conditions in recent years. Moreover, recent human-induced turning points in ecosystem functioning were detected and attributed to ongoing recultivation and change in irrigation practices in the Volgograd region, and to increased salinization and increased grazing intensity around Lake Balkhash. The ecosystem-state assessment method introduced here proved to be a valuable support that highlighted hotspots of potentially altered ecosystems and allowed for disentangling human from climatic disturbances. © 2016 John Wiley & Sons Ltd.

Benthic algae compensate for phytoplankton losses in large aquatic ecosystems.

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Brothers, Soren; Vadeboncoeur, Yvonne; Sibley, Paul

2016-12-01

Anthropogenic activities can induce major trophic shifts in aquatic systems, yet we have an incomplete understanding of the implication of such shifts on ecosystem function and on primary production (PP) in particular. In recent decades, phytoplankton biomass and production in the Laurentian Great Lakes have declined in response to reduced nutrient concentrations and invasive mussels. However, the increases in water clarity associated with declines in phytoplankton may have positive effects on benthic PP at the ecosystem scale. Have these lakes experienced oligotrophication (a reduction of algal production), or simply a shift in autotrophic structure with no net decline in PP? Benthic contributions to ecosystem PP are rarely measured in large aquatic systems, but our calculations based on productivity rates from the Great Lakes indicate that a significant proportion (up to one half, in Lake Huron) of their whole-lake production may be benthic. The large declines (5-45%) in phytoplankton production in the Great Lakes from the 1970s to 2000s may be substantially compensated by benthic PP, which increased by up to 190%. Thus, the autotrophic productive capacity of large aquatic ecosystems may be relatively resilient to shifts in trophic status, due to a redirection of production to the near-shore benthic zone, and large lakes may exhibit shifts in autotrophic structure analogous to the regime shifts seen in shallow lakes. © 2016 John Wiley & Sons Ltd.

Difference scheme for a singularly perturbed parabolic convection-diffusion equation in the presence of perturbations

Science.gov (United States)

Shishkin, G. I.

2015-11-01

An initial-boundary value problem is considered for a singularly perturbed parabolic convection-diffusion equation with a perturbation parameter ɛ (ɛ ∈ (0, 1]) multiplying the highest order derivative. The stability of a standard difference scheme based on monotone approximations of the problem on a uniform mesh is analyzed, and the behavior of discrete solutions in the presence of perturbations is examined. The scheme does not converge ɛ-uniformly in the maximum norm as the number of its grid nodes is increased. When the solution of the difference scheme converges, which occurs if N -1 ≪ ɛ and N -1 0 ≪ 1, where N and N 0 are the numbers of grid intervals in x and t, respectively, the scheme is not ɛ-uniformly well conditioned or stable to data perturbations in the grid problem and to computer perturbations. For the standard difference scheme in the presence of data perturbations in the grid problem and/or computer perturbations, conditions on the "parameters" of the difference scheme and of the computer (namely, on ɛ, N, N 0, admissible data perturbations in the grid problem, and admissible computer perturbations) are obtained that ensure the convergence of the perturbed solutions. Additionally, the conditions are obtained under which the perturbed numerical solution has the same order of convergence as the solution of the unperturbed standard difference scheme.

Microbial Functional Gene Diversity Predicts Groundwater Contamination and Ecosystem Functioning.

Science.gov (United States)

He, Zhili; Zhang, Ping; Wu, Linwei; Rocha, Andrea M; Tu, Qichao; Shi, Zhou; Wu, Bo; Qin, Yujia; Wang, Jianjun; Yan, Qingyun; Curtis, Daniel; Ning, Daliang; Van Nostrand, Joy D; Wu, Liyou; Yang, Yunfeng; Elias, Dwayne A; Watson, David B; Adams, Michael W W; Fields, Matthew W; Alm, Eric J; Hazen, Terry C; Adams, Paul D; Arkin, Adam P; Zhou, Jizhong

2018-02-20

Contamination from anthropogenic activities has significantly impacted Earth's biosphere. However, knowledge about how environmental contamination affects the biodiversity of groundwater microbiomes and ecosystem functioning remains very limited. Here, we used a comprehensive functional gene array to analyze groundwater microbiomes from 69 wells at the Oak Ridge Field Research Center (Oak Ridge, TN), representing a wide pH range and uranium, nitrate, and other contaminants. We hypothesized that the functional diversity of groundwater microbiomes would decrease as environmental contamination (e.g., uranium or nitrate) increased or at low or high pH, while some specific populations capable of utilizing or resistant to those contaminants would increase, and thus, such key microbial functional genes and/or populations could be used to predict groundwater contamination and ecosystem functioning. Our results indicated that functional richness/diversity decreased as uranium (but not nitrate) increased in groundwater. In addition, about 5.9% of specific key functional populations targeted by a comprehensive functional gene array (GeoChip 5) increased significantly ( P contamination and ecosystem functioning. This study indicates great potential for using microbial functional genes to predict environmental contamination and ecosystem functioning. IMPORTANCE Disentangling the relationships between biodiversity and ecosystem functioning is an important but poorly understood topic in ecology. Predicting ecosystem functioning on the basis of biodiversity is even more difficult, particularly with microbial biomarkers. As an exploratory effort, this study used key microbial functional genes as biomarkers to provide predictive understanding of environmental contamination and ecosystem functioning. The results indicated that the overall functional gene richness/diversity decreased as uranium increased in groundwater, while specific key microbial guilds increased significantly as

Non-Perturbative Asymptotic Improvement of Perturbation Theory and Mellin-Barnes Representation

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Samuel Friot

2010-10-01

Full Text Available Using a method mixing Mellin-Barnes representation and Borel resummation we show how to obtain hyperasymptotic expansions from the (divergent formal power series which follow from the perturbative evaluation of arbitrary ''N-point'' functions for the simple case of zero-dimensional φ4 field theory. This hyperasymptotic improvement appears from an iterative procedure, based on inverse factorial expansions, and gives birth to interwoven non-perturbative partial sums whose coefficients are related to the perturbative ones by an interesting resurgence phenomenon. It is a non-perturbative improvement in the sense that, for some optimal truncations of the partial sums, the remainder at a given hyperasymptotic level is exponentially suppressed compared to the remainder at the preceding hyperasymptotic level. The Mellin-Barnes representation allows our results to be automatically valid for a wide range of the phase of the complex coupling constant, including Stokes lines. A numerical analysis is performed to emphasize the improved accuracy that this method allows to reach compared to the usual perturbative approach, and the importance of hyperasymptotic optimal truncation schemes.

Meridional Modes and Increasing Pacific Decadal Variability Under Anthropogenic Forcing

Science.gov (United States)

Liguori, Giovanni; Di Lorenzo, Emanuele

2018-01-01

Pacific decadal variability has strong impacts on the statistics of weather, atmosphere extremes, droughts, hurricanes, marine heatwaves, and marine ecosystems. Sea surface temperature (SST) observations show that the variance of the El Niño-like decadal variability has increased by 30% (1920-2015) with a stronger coupling between the major Pacific climate modes. Although we cannot attribute these trends to global climate change, the examination of 30 members of the Community Earth System Model Large Ensemble (LENS) forced with the RCP8.5 radiative forcing scenario (1920-2100) suggests that significant anthropogenic trends in Pacific decadal variance will emerge by 2020 in response to a more energetic North Pacific Meridional Mode (PMM)—a well-known El Niño precursor. The PMM is a key mechanism for energizing and coupling tropical and extratropical decadal variability. In the LENS, the increase in PMM variance is consistent with an intensification of the winds-evaporation-SST thermodynamic feedback that results from a warmer mean climate.

Natural resource management in a protected area of the Indian Himalayas: a modeling approach for anthropogenic interactions on ecosystem.

Science.gov (United States)

Nautiyal, Sunil; Kaechele, Harald

2009-06-01

The concept of ecosystem conservation as a broad theme came into existence during the 1970s under the Man and Biosphere Programme (MAB) of the United Nations Educational, Scientific and Cultural Organization (UNESCO). The Indian Government followed this approach and chose the method to segregate the landscape for conservation of the ecosystem as well as for the development of the local economy and its people. We have examined the effect of this policy and concurrently developed a theoretical modeling approach to understand how human behavior is changing under shifting political, socioeconomic and environmental conditions. A specific focus has been on how the landscape is changing in the mountains of the Indian Himalayan region where about 10% of the total geographical area is converted into protected landscape for conservation of biodiversity. For local people living in the Himalayan mountains in India, agriculture is the main land use activity and is strongly linked to the forests in providing sustainability. There are several branches in the rural ecosystems where the local people's economy was centered. These include agriculture, animal husbandry, medicinal and aromatic plants cultivation, forest resource collection, tourism and other occupations. The greatest proportion of the population was engaged in the agriculture sector, whose contribution is high in the rural economy (61%); followed by animal husbandry (19%), forest resource collection for economic gain (18%), and medicinal and aromatic plants cultivation (1.5%). However, three decades ago the animal husbandry branch of the rural ecosystem was contributing the maximum share towards rural household income (40%) followed by tourism (35.2%), and lastly agriculture (14%). The desire of farmers to secure the optimum output from agricultural land use has resulted in an increase for resource collection from the forests. The people's perception (n = 1,648) regarding overall changes occurring in the region was

Response of mosquitofish (Gambusia affinis) populations to seasonally unpredictable perturbations

Energy Technology Data Exchange (ETDEWEB)

Horn, M.J.; Stewart, A.J.

1990-07-01

Many questions remain unresolved about the linkages between life history attributes of fishes and the tactics that these organisms employ in response to environmental uncertainty. Such questions include (1). If a perturbation affects the entire ecosystem, what are the consequences for a given population of fish (2) What tactics can a fish employ to increase its chances of leaving offspring (3) Do fish respond differently to such perturbations depending on the season (4) How do these changes relate to the overall resilience of the population The research reported here was designed to address such questions. Mosquito fish (Gambusia affinis) populations in thirteen experimental ponds at Oak Ridge National Laboratory were sampled ten times between June 1988, and July 1989 in response to a series of chemical disturbances. During each sampling period the population size and total biomass of Gambusia in each pond was estimated using photographs and a length weight regression. Size-frequency histograms were used to examine seasonal and dose-related changes in population structure. Lipid content and reproductive allotment were measured for a series of fish from each pond on all dates to explore the energy allocation patterns at the individual. 106 refs., 38 figs., 16 tabs.

Changes in food web structure and ecosystem functioning of a large, shallow Chinese lake during the 1950s, 1980s and 2000s

DEFF Research Database (Denmark)

Kong, Xiangzhen; He, Wei; Liu, Wenxiu

2016-01-01

that hydrological regulation may play a significant role in driving all of these changes in Lake Chaohu in addition to eutrophication and intensive fishery. Overall, we strongly advocate the identification of a threshold in abundance of zooplanktivorous fish, an integrated strategy for future ecological restoration......Food web structure dynamics and ecosystem functioning are strongly linked, and both are indispensable in evaluating ecosystem development in lakes under multiple anthropogenic stressors. However, model-based approaches concerning the changes in food web structure and ecosystem functioning...... validated by the stable isotope-determined trophic level (TL) for each functional group, which indicated an acceptable model performance. Over time, we observed a collapse of the food web toward a simplified structure and decreasing biodiversity and trophic interactions. The lake ecosystem was approaching...

A conceptual approach to integrate management of ecosystem service and disservice in coastal wetlands

Directory of Open Access Journals (Sweden)

Jon Knight

2017-04-01

Full Text Available Management of coastal wetlands is increasingly difficult because of increasing pressure arising from anthropogenic causes. These include sea level and climate change as well as coastline development caused by population growth and demographic shifts, for example, amenity migration where people move to coastal communities for lifestyle reasons. Management of mangroves and salt marshes is especially difficult because maintaining ecosystem values, including the goods and services provided, is countered by the potential of enhancing or even creating ecosystem disservices, such as unpleasant odour and mosquito hazards. Here we present, explain and apply a conceptual model aimed at improving understanding of management choices that primarily focus on mitigation of disservice while enabling improvement in ecosystem services. The model was developed after more than 30 years of habitat management following modification of a salt marsh to control mosquito production. We discuss the application of the model in a mangrove forest known to produce mosquitoes and outline the benefits arising from using the model.

A test of critical thresholds and their indicators in a desertification-prone ecosystem: more resilience than we thought

Science.gov (United States)

Theoretical models predict that dryland ecosystems can cross critical thresholds after which vegetation loss is independent of initial drivers, but experimental data are nonexistent. We used a long-term (13 year) pulse-perturbation experiment featuring heavy grazing and shrub removal to determine i...

Anthropogenic nitrogen deposition ameliorates the decline in tree growth caused by a drier climate.

Science.gov (United States)

Ibáñez, Inés; Zak, Donald R; Burton, Andrew J; Pregitzer, Kurt S

2018-02-01

Most forest ecosystems are simultaneously affected by concurrent global change drivers. However, when assessing these effects, studies have mainly focused on the responses to single factors and have rarely evaluated the joined effects of the multiple aspects of environmental change. Here, we analyzed the combined effects of anthropogenic nitrogen (N) deposition and climatic conditions on the radial growth of Acer saccharum, a dominant tree species in eastern North American forests. We capitalized on a long-term N deposition study, replicated along a latitudinal gradient, that has been taking place for more than 20 yr. We analyzed tree radial growth as a function of anthropogenic N deposition (ambient and experimental addition) and of summer temperature and soil water conditions. Our results reveal that experimental N deposition enhances radial growth of this species, an effect that was accentuated as temperature increased and soil water became more limiting. The spatial and temporal extent of our data also allowed us to assert that the positive effects of growing under the experimental N deposition are likely due to changes in the physiological performance of this species, and not due to the positive correlation between soil N and soil water holding capacity, as has been previously speculated in other studies. Our simulations of tree growth under forecasted climate scenarios specific for this region also revealed that although anthropogenic N deposition may enhance tree growth under a large array of environmental conditions, it will not mitigate the expected effects of growing under the considerably drier conditions characteristic of our most extreme climatic scenario. © 2018 by the Ecological Society of America.

Intensification of Chile-Peru upwelling under climate change: diagnosing the impact of natural and anthropogenic forcing from the IPSL-CM5 model.

Science.gov (United States)

Jebri, B.; Khodri, M.; Gastineau, G.; Echevin, V.; Thiria, S.

2017-12-01

Upwelling is critical to the biological production, acidification, and deoxygenation of the ocean's major eastern boundary current ecosystems. A conceptual hypothesis suggests that the winds that favour coastal upwelling intensify with anthropogenic global warming due to increased land-sea temperature contrast. We examine this hypothesis for the dynamics of the Peru-Chile upwelling using a set of four large ensembles of coupled, ocean-atmosphere model simulations with the IPSL model covering the 1940-2014 period. In one large ensemble we prescribe the standard CMIP5 greenhouse gas (GHG) concentrations, anthropogenic aerosol, ozone and volcanic forcings, following the historical experiments through 2005 and RCP8.5 from 2006-2014, while the other ensembles consider separately the GHG, ozone and volcanic forcings. We find evidence for intensification of upwelling-favourable winds with however little evidence of atmospheric pressure gradients in response to increasing land-sea temperature differences. Our analyses reveal poleward migration and intensification of the South Pacific Anticyclone near poleward boundaries of climatological Peruvian and Chilean upwelling zones. This contribution further investigates the physical mechanisms for the Peru-Chile upwelling intensification and the relative role of natural and anthropogenic forcings.

El Niño and similar perturbation effects on the benthos of the Humboldt, California, and Benguela Current upwelling ecosystems

Directory of Open Access Journals (Sweden)

W. E. Arntz

2006-01-01

zones, bringing a variety of (subtropical immigrants. The autochthonous benthic fauna emigrates to deeper water or poleward, or suffers mortality. However, some local macrofaunal species experience important population proliferations, presumably due to improved oxygenation (in the southern hemisphere, higher temperature tolerance, reduced competition or the capability to use different food. Both these negative and positive effects of El Niño influence local artisanal fisheries and the livelihood of coastal populations. In the Humboldt Current system the hypoxic seafloor at outer shelf depths receives important flushing from the equatorial zone, causing havoc on the sulphur bacteria mats and immediate recolonisation of the sediments by mega- and macrofauna. Conversely, off California, the intruding equatorial water masses appear to have lower oxygen than ambient waters, and may cause oxygen deficiency at upper slope depths. Effects of this change have not been studied in detail, although shrimp and other taxa appear to alter their distribution on the continental margin. Other properties and reactions of the two Pacific EBC benthic ecosystems to El Niño seem to differ, too, as does the overall impact of major episodes (e.g., 1982/1983(1984 vs. 1997/1998. The relation of the "Benguela Niño" to ENSO seems unclear although many Pacific-Atlantic ocean and atmosphere teleconnections have been described. Warm, low-oxygen equatorial water seems to be transported into the upwelling area by similar mechanisms as in the Pacific, but most major impacts on the eukaryotic biota obviously come from other, independent perturbations such as an extreme eutrophication of the sediments ensuing in sulphidic eruptions and toxic algal blooms. Similarities and differences of the Humboldt and California Current benthic ecosystems are discussed with particular reference to ENSO impacts since 1972/73. Where there are data available, the authors include the Benguela Current ecosystem as another

[Developmental instability of the organism as a result of pessimization of environment under anthropogenic transformation of natural landscapes].

Science.gov (United States)

Shadrina, E G; Vol'pert, Ia L

2014-01-01

The value of fluctuating asymmetry is considered to be an indicator of the developmental instability of the organism. The consequences of activities of the mining industry plants, which are characterized by alienation and transformation of large areas of natural landscapes, are analyzed as an anthropogenic factor. The objects of study were small mammals (northern red-backed (Clethrionomys rutilus) and gray red-backed (Clethrionomys rufocanus) voles, tundra vole (Microtus oeconomus), Laxmann's (Sorex caecutiens) and tundra (S. tundrensis) shrews) and trees (Japanese white birch (Betula platyphylla), Betula divaricate, Betula exilis, Duschekiafruticosa, and common osier (Salix viminalis)). In total, 3500 skulls and approximately 30000 leaves collected in the taiga zone of Yakutia were studied. The index offluctuating asymmetry, as well as population parameters and composition of small mammal communities, were analyzed. The data on the value of the fluctuating asymmetry in the studied species in natural habitats are given. It is shown that, in natural conditions, this parameter can rise with deterioration in living conditions, particularly at the ecological periphery of the range. Anthropogenic transformation of natural landscapes creates an "anthropogenic periphery" and causes changes similar to the adaptive responses at the northern limit of the distribution of species. It was found that, through pollution and disruption of ecosystems, the mining industry affects all levels of organization of the living matter, but the population and cenotic parameters give an unambiguous response only at macroanthropogenic transformations. Increase in the level of fluctuating asymmetry is the most sensitive indicator of anthropogenic impact and it should also be taken into account that disruptions in the developmental stability of an organism reflect the destructive processes occurring in the population and community.

Integrated assessment of the impact of chemical stressors on surface water ecosystems

DEFF Research Database (Denmark)

McKnight, Ursula S; Rasmussen, Jes J; Kronvang, Brian

2012-01-01

of chemical stressors on stream ecosystems are evaluated for a stream in Denmark where the effects of major physical habitat degradation can be disregarded. The methods are: (i) the Danish Stream Fauna Index, (ii) Toxic Units (TU), (iii) SPEAR indices, (iv) Hazard Quotient (HQ) index and (v) AQUATOX...... of this case study, the HQ index and AQUATOX were extended for additional compounds, not only partly to identify potential compounds of concern, but also to determine thresholds where ecological impacts could be expected to occur. The results demonstrate that some commonly used methods for the assessment...... of ecological impact are not sufficient for capturing - and ideally separating - the effects of all anthropogenic stressors affecting ecosystems. Predictive modelling techniques can be especially useful in supporting early decisions on prioritising hot spots, serving to identify knowledge gaps and thereby...

Stationary axially symmetric perturbations of a rotating black hole. [Space-time perturbation, Newman-Penrose formalism

Energy Technology Data Exchange (ETDEWEB)

Demianski, M [California Inst. of Tech., Pasadena (USA)

1976-07-01

A stationary axially symmetric perturbation of a rotating black hole due to a distribution of test matter is investigated. The Newman-Penrose spin coefficient formalism is used to derive a general set of equations describing the perturbed space-time. In a linear approximation it is shown that the mass and angular momentum of a rotating black hole is not affected by the perturbation. The metric perturbations near the horizon are given. It is concluded that given a perturbing test fluid distribution, one can always find a corresponding metric perturbation such that the mass and angular momentum of the black hole are not changed. It was also noticed that when a tends to M, those perturbed spin coefficients and components of the Weyl tensor which determine the intrinsic properties of the incoming null cone near the horizon grow indefinitely.

Anthropogenic Biomes of the World, Version 2: 1700

Data.gov (United States)

National Aeronautics and Space Administration — The Anthropogenic Biomes of the World, Version 2: 1700 data set describes anthropogenic transformations within the terrestrial biosphere caused by sustained direct...

Anthropogenic Biomes of the World, Version 2: 1900

Data.gov (United States)

National Aeronautics and Space Administration — The Anthropogenic Biomes of the World, Version 2: 1900 data set describes anthropogenic transformations within the terrestrial biosphere caused by sustained direct...

Anthropogenic Biomes of the World, Version 2: 1800

Data.gov (United States)

National Aeronautics and Space Administration — The Anthropogenic Biomes of the World, Version 2: 1800 data set describes anthropogenic transformations within the terrestrial biosphere caused by sustained direct...

Anthropogenic Biomes of the World, Version 2: 2000

Data.gov (United States)

National Aeronautics and Space Administration — The Anthropogenic Biomes of the World, Version 2: 2000 data set describes anthropogenic transformations within the terrestrial biosphere caused by sustained direct...

Decadal ecosystem response to an anomalous melt season in a polar desert in Antarctica.

Science.gov (United States)

Gooseff, Michael N; Barrett, John E; Adams, Byron J; Doran, Peter T; Fountain, Andrew G; Lyons, W Berry; McKnight, Diane M; Priscu, John C; Sokol, Eric R; Takacs-Vesbach, Cristina; Vandegehuchte, Martijn L; Virginia, Ross A; Wall, Diana H

2017-09-01

Amplified climate change in polar regions is significantly altering regional ecosystems, yet there are few long-term records documenting these responses. The McMurdo Dry Valleys (MDV) cold desert ecosystem is the largest ice-free area of Antarctica, comprising soils, glaciers, meltwater streams and permanently ice-covered lakes. Multi-decadal records indicate that the MDV exhibited a distinct ecosystem response to an uncharacteristic austral summer and ensuing climatic shift. A decadal summer cooling phase ended in 2002 with intense glacial melt ('flood year')-a step-change in water availability triggering distinct changes in the ecosystem. Before 2002, the ecosystem exhibited synchronous behaviour: declining stream flow, decreasing lake levels, thickening lake ice cover, decreasing primary production in lakes and streams, and diminishing soil secondary production. Since 2002, summer air temperatures and solar flux have been relatively consistent, leading to lake level rise, lake ice thinning and elevated stream flow. Biological responses varied; one stream cyanobacterial mat type immediately increased production, but another stream mat type, soil invertebrates and lake primary productivity responded asynchronously a few years after 2002. This ecosystem response to a climatic anomaly demonstrates differential biological community responses to substantial perturbations, and the mediation of biological responses to climate change by changes in physical ecosystem properties.

Linking Marine Ecosystem Services to the North Sea’s Energy Fields in Transnational Marine Spatial Planning

Directory of Open Access Journals (Sweden)

Christina Vogel

2018-06-01

Full Text Available Marine spatial planning temporally and spatially allocates marine resources to different users. The ecosystem approach aims at optimising the social and economic benefits people derive from marine resources while preserving the ecosystem’s health. Marine ecosystem services are defined as the benefits people obtain from marine ecosystems. The aim of this study is to determine which interrelations between marine ecosystem services and the marine energy industry can be identified for use in transnational marine spatial planning exemplified in the North Sea region. As the North Sea is one of the busiest seas worldwide, the risk of impairing the ecosystems through anthropogenic pressures is high. Drawing on a literature-based review, 23 marine ecosystem services provided by the North Sea region were defined and linked to seven offshore energy fields comprising oil and natural gas, wind, tides and currents, waves, salinity gradients, algal biomass, and geothermal heat. The interactions were divided into four categories: dependence, impact, bidirectional, or no interaction. Oil and natural gas, as well as algae biomass, are the fields with the most relations with marine ecosystem services while waves and salinity gradients exhibit the least. Some marine ecosystem services (Conditions for Infrastructure, Regulation of Water Flows, and Cognitive Development are needed for all fields; Recreation and Tourism, Aesthetic and Cultural Perceptions and Traditions, Cognitive Development, and Sea Scape are impacted by all fields. The results of this research provide an improved basis for an ecosystem approach in transnational marine spatial planning.

Anthropogenic impact on biogenic substance distribution and bacterial community in sediment along the Yarlung Tsangpo River on Tibet Plateau, China

Science.gov (United States)

Wang, C.; Peifang, W.; Wang, X.; Hou, J.; Miao, L.

2017-12-01

Lotic river system plays an important part in water-vapor transfer and biogenic substances migration and transformation. Anthropogenic activities, including wastewater discharging and river damming, have altered river ecosystem and continuum. However, as the longest alpine river in China and suffered from increasing anthropogenic activities, the Yarlung Tsangpo River has been rarely studied. Recently, more attention has also been paid to the bacteria in river sediment as they make vital contributions to the biogeochemical nutrient cycling. Here, the distribution of biogenic substances, including nitrogen, phosphorus, silicon and carbon, was explored in both water and sediment of the Yarlung Tsangpo River. By using the next generation 16S rRNA sequencing, the bacterial diversity and structure in river sediment were presented. The results indicated that the nutrient concentrations increased in densely populated sites, revealing that biogenic substance distribution corresponded with the intensity of anthropogenic activity along the river. Nitrogen, phosphorus, silicon and carbon in water and sediment were all retained by the Zangmu Dam which is the only dam in the mainstream of the river. Moreover, the river damming decreased the biomass and diversity of bacteria in sediment, but no significant alteration of community structure was observed upstream and downstream of the dam. The most dominant bacteria all along the river was Proteobacteria. Meanwhile, Verrucomicrobia and Firmicutes also dominated the community composition in upstream and downstream of the river, respectively. In addition, total organic carbon (TOC) was proved to be the most important environmental factor shaping the bacterial community in river sediment. Our study offered the preliminary insights into the biogenic substance distribution and bacterial community in sediment along an alpine river which was affected by anthropogenic activities. In the future, more studies are needed to reveal the

Environmental and Human Controls of Ecosystem Functional Diversity in Temperate South America

Directory of Open Access Journals (Sweden)

Domingo Alcaraz-Segura

2013-01-01

Full Text Available The regional controls of biodiversity patterns have been traditionally evaluated using structural and compositional components at the species level, but evaluation of the functional component at the ecosystem level is still scarce. During the last decades, the role of ecosystem functioning in management and conservation has increased. Our aim was to use satellite-derived Ecosystem Functional Types (EFTs, patches of the land-surface with similar carbon gain dynamics to characterize the regional patterns of ecosystem functional diversity and to evaluate the environmental and human controls that determine EFT richness across natural and human-modified systems in temperate South America. The EFT identification was based on three descriptors of carbon gain dynamics derived from seasonal curves of the MODIS Enhanced Vegetation Index (EVI: annual mean (surrogate of primary production, seasonal coefficient of variation (indicator of seasonality and date of maximum EVI (descriptor of phenology. As observed for species richness in the southern hemisphere, water availability, not energy, emerged as the main climatic driver of EFT richness in natural areas of temperate South America. In anthropogenic areas, the role of both water and energy decreased and increasing human intervention increased richness at low levels of human influence, but decreased richness at high levels of human influence.

Madagascar’s Mangroves: Quantifying Nation-Wide and Ecosystem Specific Dynamics, and Detailed Contemporary Mapping of Distinct Ecosystems

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Trevor G. Jones

2016-01-01

Full Text Available Mangrove ecosystems help mitigate climate change, are highly biodiverse, and provide critical goods and services to coastal communities. Despite their importance, anthropogenic activities are rapidly degrading and deforesting mangroves world-wide. Madagascar contains 2% of the world’s mangroves, many of which have undergone or are starting to exhibit signs of widespread degradation and deforestation. Remotely sensed data can be used to quantify mangrove loss and characterize remaining distributions, providing detailed, accurate, timely and updateable information. We use USGS maps produced from Landsat data to calculate nation-wide dynamics for Madagascar’s mangroves from 1990 to 2010, and examine change more closely by partitioning the national distribution in to primary (i.e., >1000 ha ecosystems; with focus on four Areas of Interest (AOIs: Ambaro-Ambanja Bays (AAB, Mahajamba Bay (MHJ, Tsiribihina Manombolo Delta (TMD and Bay des Assassins (BdA. Results indicate a nation–wide net-loss of 21% (i.e., 57,359 ha from 1990 to 2010, with dynamics varying considerably among primary mangrove ecosystems. Given the limitations of national-level maps for certain localized applications (e.g., carbon stock inventories, building on two previous studies for AAB and MHJ, we employ Landsat data to produce detailed, contemporary mangrove maps for TMD and BdA. These contemporary, AOI-specific maps provide improved detail and accuracy over the USGS national-level maps, and are being applied to conservation and restoration initiatives through the Blue Ventures’ Blue Forests programme and WWF Madagascar West Indian Ocean Programme Office’s work in the region.

Food web structure and vulnerability of a deep-sea ecosystem in the NW Mediterranean Sea

OpenAIRE

Tecchio, Samuele; Coll, Marta; Christensen, Villy; Company, Joan B.; Ramirez-Llodra, Eva; Sarda, Francisco

2013-01-01

There is increasing fishing pressure on the continental margins of the oceans, and this raises concerns about the vulnerability of the ecosystems thriving there. The current knowledge of the biology of deep-water fish species identifies potential reduced resilience to anthropogenic disturbance. However, there are extreme difficulties in sampling the deep sea, resulting in poorly resolved and indirectly obtained food-web relationships. Here, we modelled the flows and biomasses of a Mediterrane...

Impacts of the Nutrient Inputs from Riverine on the Dynamic and Community Structure of Fungal-like Protists in the Coastal Ocean Ecosystems

Science.gov (United States)

Duan, Y.; Wang, G.; Xie, N.

2016-02-01

The coastal ocean connects terrestrial (e.g., rivers and estuaries) with oceanic ecosystems and is considered as a major component of global carbon cycles and budgets. The coastal waters are featured with a high biodiversity and high primary production. Because of the excessive primary production, a large fraction of primary organic matter becomes available to consumers as detritus in the coastal waters. Bacterioplankton have long been known to play a key role in the degradation of this detritus, and export and storage of organic matter in the coastal ecosystems. However, the primary and secondary production and the carbon biogeochemical processes in the ecosystems are largely regulated by nutrient inputs from riverine and other anthropogenic activities through heterotrophic microbial communities. Thraustochytrids, commonly known as fungal-like protists, are unicellular heterotrophic protists and are recently acknowledged to play a significant role in ocean carbon cycling. Their abundance exceeds that of bacterioplankton in the most time of the year in the coastal waters of China. Also, their abundance and diversity are largely regulated by nutrients inputs from riverine and other anthropogenic activities. Our findings support that thraustochytrids are a dominant heterotrophic microbial group in the coastal waters. Evidently, thraustochytrids are an import, but neglected, component in microbial carbon biogeochemical processes of the coastal ocean.

Farmers’ Value Assessment of Sociocultural and Ecological Ecosystem Services in Agricultural Landscapes

Directory of Open Access Journals (Sweden)

Habtamu Temesgen

2018-03-01

Full Text Available Biophysical and economic values of ecosystem services (ESs are commonly used to define areas for land use and management planning. To date, there has been limited research conducted in Ethiopia regarding farmers’ evaluations of ESs. This article addresses farmers’ evaluations and perceptions of 16 ESs that are provided by five major land uses within two catchments, using a combined method of data generation and synthesis. Most farmers perceived the majority of land use/land cover (LUC types as multifunctional; however, they showed distinctly diverse opinions of the benefits and services that the land uses provide. The farmers also distinguished pristine ESs as different importantance depending on their location in up- or downstream regions. Accordingly, shade and shelter values in the upstream region and fodder sources in the downstream regions were among the services perceived as the most important, followed by erosion control. Conversely, water treatment and tenure security were attributed poor value. Farmers’ also identified various threats to the studied ESs that were believed to be the consequences of overpopulation coupled with climate change. Routine anthropogenic activities, woodlots extraction, agribusiness investment, and drought and rainfall variability appeared to be the main drivers of these threats. The farmers’ perceptions recorded in this study generally parallel empirical research, wherein anthropogenic and environmental challenges affect the ecosystems. This general consensus represents an important basis for the establishment of collaborative land management activities.

Prairie dog decline reduces the supply of ecosystem services and leads to desertification of semiarid grasslands.

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Lourdes Martínez-Estévez

Full Text Available Anthropogenic impacts on North American grasslands, a highly endangered ecosystem, have led to declines of prairie dogs, a keystone species, over 98% of their historical range. While impacts of this loss on maintenance of grassland biodiversity have been widely documented, much less is known about the consequences on the supply of ecosystem services. Here we assessed the effect of prairie dogs in the supply of five ecosystem services by comparing grasslands currently occupied by prairie dogs, grasslands devoid of prairie dogs, and areas that used to be occupied by prairie dogs that are currently dominated by mesquite scrub. Groundwater recharge, regulation of soil erosion, regulation of soil productive potential, soil carbon storage and forage availability were consistently quantitatively or qualitatively higher in prairie dog grasslands relative to grasslands or mesquite scrub. Our findings indicate a severe loss of ecosystem services associated to the absence of prairie dogs. These findings suggest that contrary to a much publicize perception, especially in the US, prairie dogs are fundamental in maintaining grasslands and their decline have strong negative impacts in human well - being through the loss of ecosystem services.

Ecological restoration, ecosystem services, and land use: a European perspective

Directory of Open Access Journals (Sweden)

Anne Tolvanen

2016-12-01

Full Text Available This special feature provides an overview on how the ecosystem service concept has been and can be incorporated into the science, practice, and policies of ecological restoration (ER and evidence-based land-use. It includes an edited selection of eleven invited and peer-reviewed papers based on presentations given during the 9th European Conference on Ecological Restoration in 2014. The focus is on Europe, but many contributors also make appraisals and recommendations at the global scale. Based on the contributors' papers, and our own overview of the promise of ecological restoration in the existing international treaties, coalitions, and conventions, we propose that the following actions could contribute to the positive impacts of ER on biodiversity maintenance, ecosystem functioning, progressive mainstreaming the concepts of both ER and ecosystem services, significant mitigation and offsetting of anthropogenic climate change, and lasting enhancement of both ecosystem and human health: •\tER should be incorporated into land use planning, wherever needed, and the synergies and trade-offs of different land use scenarios should be assessed in terms of their impacts on ecosystem services. •\tThe discourse of ER should be enlarged, wherever it is needed, to include multifunctional land use that simultaneously supports sustainable production systems, built environments, and the quality and quantity of diverse ecosystem services. This approach will generate ecological, social, and economic benefits in the long run. •\tMonitoring and evaluation of ER projects should be a continuous process involving careful selection of indicators chosen with the full range of stakeholders in mind, and a sufficiently long-term perspective to catch the progress of long-term or highly dynamic ecosystem processes. •\tScientists should actively participate in policy and land management discussions in order to give their views on the potential outcomes of decisions. �

Anthropogenic effect on avalanche and debris flow activity

OpenAIRE

S. A. Sokratov; Yu. G. Seliverstov; A. L. Shnyparkov; K. P. Koltermann

2013-01-01

The paper presents examples of the change in snow avalanches and debris flows activity due to the anthropogenic pressure on vegetation and relief. The changes in dynamical characteristics of selected snow avalanches and debris flows due to the anthropogenic activity are quantified. The conclusion is made that the anthropogenic effects on the snow avalanches and debris flows activity are more pronounced than the possible effects of the climate change. The necessity is expressed on the unavoida...

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

Science.gov (United States)

Zhao, Dongsheng; Wu, Shaohong; Yin, Yunhe

2013-01-01

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

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

Directory of Open Access Journals (Sweden)

Dongsheng Zhao

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

What is the impact on fish recruitment of anthropogenic physical and structural habitat change in shallow nearshore areas in temperate systems? A systematic review protocol

DEFF Research Database (Denmark)

MacUra, B.; Lönnstedt, O.M.; Byström, P.

2016-01-01

and spawning habitats of many fish and other aquatic species. Several coastal fish populations have seen marked declines in abundance and diversity during the past two decades. A systematic review on the topic would clarify if anthropogenic physical and structural changes of near-shore areas have effects...... on fish recruitment and which these effects are. Methods: The review will examine how various physical and structural anthropogenic changes of nearshore fish habitats affect fish recruitment. Relevant studies include small- and large-scale field studies in marine and brackish systems or large lakes......Background: Shallow nearshore marine ecosystems are changing at an increasing rate due to a range of human activities such as urbanisation and commercial development. The growing numbers of constructions and other physical and structural alterations of the shoreline often take place in nursery...

Influence of cultivation regime of an arbuscular mycorrhizal fungal isolate on its symbiotic efficacy in phyto restoration of disturbed ecosystems

International Nuclear Information System (INIS)

Oliveira, R. S.; Vosatka, M.; Castro, P. M. L.; Dodd, J. C.

2009-01-01

Arbuscular mycorrhizal fungi (AMF), from the Phylum Glomeromycota, are a group of soil organisms that forms symbiotic associations with plant roots and can contribute to increase plant biomass and promote phyto restoration of disturbed ecosystems. The influence of cultivation regime of a Glomus geosporum isolate, obtained from a highly alkaline anthropogenic sediment, on its symbiotic efficacy was investigated. (Author)

Influence of cultivation regime of an arbuscular mycorrhizal fungal isolate on its symbiotic efficacy in phyto restoration of disturbed ecosystems

Energy Technology Data Exchange (ETDEWEB)

Oliveira, R. S.; Vosatka, M.; Castro, P. M. L.; Dodd, J. C.

2009-07-01

Arbuscular mycorrhizal fungi (AMF), from the Phylum Glomeromycota, are a group of soil organisms that forms symbiotic associations with plant roots and can contribute to increase plant biomass and promote phyto restoration of disturbed ecosystems. The influence of cultivation regime of a Glomus geosporum isolate, obtained from a highly alkaline anthropogenic sediment, on its symbiotic efficacy was investigated. (Author)

Establishing research strategies, methodologies and technologies to link genomics and proteomics to seagrass productivity, community metabolism and ecosystem carbon fluxes

Directory of Open Access Journals (Sweden)

Silvia eMazzuca

2013-03-01

Full Text Available A complete understanding of the mechanistic basis of marine ecosystem functioning is only possible through integrative and interdisciplinary research. This enables the prediction of change and possibly the mitigation of the consequences of anthropogenic impacts. One major aim of the COST Action ES0609 Seagrasses productivity. From genes to ecosystem management, is the calibration and synthesis of various methods and the development of innovative techniques and protocols for studying seagrass ecosystems.During ten days, twenty researchers representing a range of disciplines (molecular biology, physiology, botany, ecology, oceanography, underwater acoustics gathered at the marine station of STARESO (Corsica to study together the nearby Posidonia oceanica meadow. The Station de Recherches Sous-marine et Océanographiques (STARESO is located in an oligotrophic area classified as "pristine site" where environmental disturbances caused by anthropogenic pressure are exceptionally low. The healthy P. oceanica meadow, that grows in front of the lab, colonizes the sea bottom from the surface to 37 m depth. During the study, genomic and proteomic approaches were integrated with ecophysiological and physical approaches with the aim of understanding changes in seagrass productivity and metabolism at different depths and along daily cycles. In this paper we report details on the approaches utilized and we forecast the potential of the data that will come from this synergistic approach not only for P. oceanica but for seagrasses in general.

Pre-Columbian agricultural landscapes, ecosystem engineers, and self-organized patchiness in Amazonia.

Science.gov (United States)

McKey, Doyle; Rostain, Stéphen; Iriarte, José; Glaser, Bruno; Birk, Jago Jonathan; Holst, Irene; Renard, Delphine

2010-04-27

The scale and nature of pre-Columbian human impacts in Amazonia are currently hotly debated. Whereas pre-Columbian people dramatically changed the distribution and abundance of species and habitats in some parts of Amazonia, their impact in other parts is less clear. Pioneer research asked whether their effects reached even further, changing how ecosystems function, but few in-depth studies have examined mechanisms underpinning the resilience of these modifications. Combining archeology, archeobotany, paleoecology, soil science, ecology, and aerial imagery, we show that pre-Columbian farmers of the Guianas coast constructed large raised-field complexes, growing on them crops including maize, manioc, and squash. Farmers created physical and biogeochemical heterogeneity in flat, marshy environments by constructing raised fields. When these fields were later abandoned, the mosaic of well-drained islands in the flooded matrix set in motion self-organizing processes driven by ecosystem engineers (ants, termites, earthworms, and woody plants) that occur preferentially on abandoned raised fields. Today, feedbacks generated by these ecosystem engineers maintain the human-initiated concentration of resources in these structures. Engineer organisms transport materials to abandoned raised fields and modify the structure and composition of their soils, reducing erodibility. The profound alteration of ecosystem functioning in these landscapes coconstructed by humans and nature has important implications for understanding Amazonian history and biodiversity. Furthermore, these landscapes show how sustainability of food-production systems can be enhanced by engineering into them follows that maintain ecosystem services and biodiversity. Like anthropogenic dark earths in forested Amazonia, these self-organizing ecosystems illustrate the ecological complexity of the legacy of pre-Columbian land use.

Chernozems microbial community under anthropogenic impact (Russia)

Science.gov (United States)

Ivashchenko, Kristina; Ananyeva, Nadezhda; Sushko, Sofia; Vasenev, Viacheslav

2017-04-01

.8 g CO2-C m-2 d-1, respectively, it was on average 2 times higher urban. The Cmic profile pool (1.5 m) in steppe was amounted to 372 g C m-2, and it was essentially higher those in bare fallow and urban (138 and 140 g C m-2, respectively). The BR profile pool (1.5 m) was also decreased along ecosystems row: steppe> fallow>urban, and it was on average 13.0, 8.0 and 5.6 g CO2-C m-2 d-1, respectively. Thus, we found a significant decreasing soil microbial biomass content, its portion in soil Corg, fungi content, and the Cmic and BR profile pools along Chernozems' ecosystems gradient from natural (virgin steppe) to anthropogenically transformed (bare fallow, urban). It might be illustrated some deterioration of soil microbial community functioning under plowing and urbanization. This research was supported by RFBR grants Nos. 15-04-00915 and 16-34-00398

Major impacts of climate change on deep-sea benthic ecosystems

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Andrew K. Sweetman

2017-02-01

Full Text Available The deep sea encompasses the largest ecosystems on Earth. Although poorly known, deep seafloor ecosystems provide services that are vitally important to the entire ocean and biosphere. Rising atmospheric greenhouse gases are bringing about significant changes in the environmental properties of the ocean realm in terms of water column oxygenation, temperature, pH and food supply, with concomitant impacts on deep-sea ecosystems. Projections suggest that abyssal (3000–6000 m ocean temperatures could increase by 1°C over the next 84 years, while abyssal seafloor habitats under areas of deep-water formation may experience reductions in water column oxygen concentrations by as much as 0.03 mL L–1 by 2100. Bathyal depths (200–3000 m worldwide will undergo the most significant reductions in pH in all oceans by the year 2100 (0.29 to 0.37 pH units. O2 concentrations will also decline in the bathyal NE Pacific and Southern Oceans, with losses up to 3.7% or more, especially at intermediate depths. Another important environmental parameter, the flux of particulate organic matter to the seafloor, is likely to decline significantly in most oceans, most notably in the abyssal and bathyal Indian Ocean where it is predicted to decrease by 40–55% by the end of the century. Unfortunately, how these major changes will affect deep-seafloor ecosystems is, in some cases, very poorly understood. In this paper, we provide a detailed overview of the impacts of these changing environmental parameters on deep-seafloor ecosystems that will most likely be seen by 2100 in continental margin, abyssal and polar settings. We also consider how these changes may combine with other anthropogenic stressors (e.g., fishing, mineral mining, oil and gas extraction to further impact deep-seafloor ecosystems and discuss the possible societal implications.

Seagrass sediments reveal the long-term deterioration of an estuarine ecosystem

KAUST Repository

Serrano, Oscar

2016-01-28

© 2016 John Wiley & Sons Ltd. The study of a Posidonia australis sediment archive has provided a record of ecosystem dynamics and processes over the last 600 years in Oyster Harbour (SW Australia). Ecosystem shifts are a widespread phenomenon in coastal areas, and this study identifies baseline conditions and the time-course of ecological change (cycles, trends, resilience and thresholds of ecosystem change) under environmental stress in seagrass-dominated ecosystem. The shifts in the concentrations of chemical elements, carbonates, sediments <0.125 mm and stable carbon isotope signatures (δ13C) of the organic matter were detected between 1850s and 1920s, whereas the shift detected in P concentration occurred several decades later (1960s). The first degradation phase (1850s-1950s) follows the onset of European settlement in Australia and was characterized by a strong increase in sediment accumulation rates and fine-grained particles, driven primarily by enhanced run-off due to land clearance and agriculture in the catchment. About 80% of total seagrass area at Oyster Harbour was lost during the second phase of environmental degradation (1960s until present). The sharp increase in P concentration and the increasing contribution of algae and terrestrial inputs into the sedimentary organic matter pool around 1960s provides compelling evidence of the documented eutrophication of the estuary and the subsequent loss of seagrass meadows. The results presented demonstrate the power of seagrass sedimentary archives to reconstruct the trajectories of anthropogenic pressures on estuarine ecosystem and the associated regime shifts, which can be used to improve the capacity of scientists and environmental managers to understand, predict and better manage ecological change in these ecosystems.

Seagrass sediments reveal the long-term deterioration of an estuarine ecosystem

KAUST Repository

Serrano, Oscar; Lavery, Paul; Masque, Pere; Inostroza, Karina; Bongiovanni, James; Duarte, Carlos M.

2016-01-01

© 2016 John Wiley & Sons Ltd. The study of a Posidonia australis sediment archive has provided a record of ecosystem dynamics and processes over the last 600 years in Oyster Harbour (SW Australia). Ecosystem shifts are a widespread phenomenon in coastal areas, and this study identifies baseline conditions and the time-course of ecological change (cycles, trends, resilience and thresholds of ecosystem change) under environmental stress in seagrass-dominated ecosystem. The shifts in the concentrations of chemical elements, carbonates, sediments <0.125 mm and stable carbon isotope signatures (δ13C) of the organic matter were detected between 1850s and 1920s, whereas the shift detected in P concentration occurred several decades later (1960s). The first degradation phase (1850s-1950s) follows the onset of European settlement in Australia and was characterized by a strong increase in sediment accumulation rates and fine-grained particles, driven primarily by enhanced run-off due to land clearance and agriculture in the catchment. About 80% of total seagrass area at Oyster Harbour was lost during the second phase of environmental degradation (1960s until present). The sharp increase in P concentration and the increasing contribution of algae and terrestrial inputs into the sedimentary organic matter pool around 1960s provides compelling evidence of the documented eutrophication of the estuary and the subsequent loss of seagrass meadows. The results presented demonstrate the power of seagrass sedimentary archives to reconstruct the trajectories of anthropogenic pressures on estuarine ecosystem and the associated regime shifts, which can be used to improve the capacity of scientists and environmental managers to understand, predict and better manage ecological change in these ecosystems.

Perturbative and constructive renormalization

International Nuclear Information System (INIS)

Veiga, P.A. Faria da

2000-01-01

These notes are a survey of the material treated in a series of lectures delivered at the X Summer School Jorge Andre Swieca. They are concerned with renormalization in Quantum Field Theories. At the level of perturbation series, we review classical results as Feynman graphs, ultraviolet and infrared divergences of Feynman integrals. Weinberg's theorem and Hepp's theorem, the renormalization group and the Callan-Symanzik equation, the large order behavior and the divergence of most perturbation series. Out of the perturbative regime, as an example of a constructive method, we review Borel summability and point out how it is possible to circumvent the perturbation diseases. These lectures are a preparation for the joint course given by professor V. Rivasseau at the same school, where more sophisticated non-perturbative analytical methods based on rigorous renormalization group techniques are presented, aiming at furthering our understanding about the subject and bringing field theoretical models to a satisfactory mathematical level. (author)

Responses of stream microbes to multiple anthropogenic stressors in a mesocosm study.

Science.gov (United States)

Nuy, Julia K; Lange, Anja; Beermann, Arne J; Jensen, Manfred; Elbrecht, Vasco; Röhl, Oliver; Peršoh, Derek; Begerow, Dominik; Leese, Florian; Boenigk, Jens

2018-08-15

Stream ecosystems are affected by multiple anthropogenic stressors worldwide. Even though effects of many single stressors are comparatively well studied, the effects of multiple stressors are difficult to predict. In particular bacteria and protists, which are responsible for the majority of ecosystem respiration and element flows, are infrequently studied with respect to multiple stressors responses. We conducted a stream mesocosm experiment to characterize the responses of single and multiple stressors on microbiota. Two functionally important stream habitats, leaf litter and benthic phototrophic rock biofilms, were exposed to three stressors in a full factorial design: fine sediment deposition, increased chloride concentration (salinization) and reduced flow velocity. We analyzed the microbial composition in the two habitat types of the mesocosms using an amplicon sequencing approach. Community analysis on different taxonomic levels as well as principle component analyses (PCoAs) based on realtive abundances of operational taxonomic units (OTUs) showed treatment specific shifts in the eukaryotic biofilm community. Analysis of variance (ANOVA) revealed that Bacillariophyta responded positively salinity and sediment increase, while the relative read abundance of chlorophyte taxa decreased. The combined effects of multiple stressors were mainly antagonistic. Therefore, the community composition in multiply stressed environments resembled the composition of the unstressed control community in terms of OTU occurrence and relative abundances. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

The role of anthropogenic water reservoirs within the landscapes of mining areas – a case study from the western part of the Upper Silesian Coal Basin

Directory of Open Access Journals (Sweden)

Jaruchiewicz Ewelina

2014-03-01

Full Text Available A few thousand anthropogenic water reservoirs can be found in the area of the Upper Silesian Coal Basis (USCB located in southern Poland. In this paper the role of such anthropogenic lakes in the landscape of the western part of the USCB was presented and illustrated with the example of Knurów, a mining city, and its immediate surrounding area. The study of landscape changes in this area was carried out on the basis of archival and contemporary cartographic materials, historical sources, and interviews with inhabitants and direct field observations. It was found that the origin of the majority of the water reservoirs is related to hard coal, clay and sand mining. They were created primarily as a result of filling subsidence basins and post-mining excavations with water, as well as being the result of the construction of various hydro-technical facilities (settling ponds, fire protection water reservoirs, etc. In the study area the anthropogenic water reservoirs are of different sizes, shapes and durability and play different roles in the environment. Between 1884 and 2001 their number increased 25-fold, while at the same time their total surface area increased more than 8-fold. The role of the newly created water reservoirs in the landscape primarily involves the transformation of the existing terrestrial ecosystems into wetland ecosystems. The agro-forestry landscape of the late 19th century was transformed into a typically anthropogenic landscape with a dominant share of water reservoirs, settlement ponds and mining waste heaps. The most common species of plants around the water reservoirs are Phragmites australis, Typha latifolia, Ceratophyllum demersum, Elodea canadensis, Potamogeton natans, Lemna sp., Acorus calamus, Myriophyllum verticillatum, Sagittaria sagittifolia, Alisma plantago-aquatica and Glyceria aquatica. The most valuable elements of the flora include Trapa natans and Ruppia maritima, species recognized in Poland as threatened

New Methods in Non-Perturbative QCD

Energy Technology Data Exchange (ETDEWEB)

Unsal, Mithat [North Carolina State Univ., Raleigh, NC (United States)

2017-01-31

In this work, we investigate the properties of quantum chromodynamics (QCD), by using newly developing mathematics and physics formalisms. Almost all of the mass in the visible universe emerges from a quantum chromodynamics (QCD), which has a completely negligible microscopic mass content. An intimately related issue in QCD is the quark confinement problem. Answers to non-perturbative questions in QCD remained largely elusive despite much effort over the years. It is also believed that the usual perturbation theory is inadequate to address these kinds of problems. Perturbation theory gives a divergent asymptotic series (even when the theory is properly renormalized), and there are non-perturbative phenomena which never appear at any order in perturbation theory. Recently, a fascinating bridge between perturbation theory and non-perturbative effects has been found: a formalism called resurgence theory in mathematics tells us that perturbative data and non-perturbative data are intimately related. Translating this to the language of quantum field theory, it turns out that non-perturbative information is present in a coded form in perturbation theory and it can be decoded. We take advantage of this feature, which is particularly useful to understand some unresolved mysteries of QCD from first principles. In particular, we use: a) Circle compactifications which provide a semi-classical window to study confinement and mass gap problems, and calculable prototypes of the deconfinement phase transition; b) Resurgence theory and transseries which provide a unified framework for perturbative and non-perturbative expansion; c) Analytic continuation of path integrals and Lefschetz thimbles which may be useful to address sign problem in QCD at finite density.

Sources, factors, mechanisms and possible solutions to pollutants in marine ecosystems

International Nuclear Information System (INIS)

Mostofa, Khan M.G.; Liu, Cong-Qiang; Vione, Davide; Gao, Kunshan; Ogawa, Hiroshi

2013-01-01

Algal toxins or red-tide toxins produced during algal blooms are naturally-derived toxic emerging contaminants (ECs) that may kill organisms, including humans, through contaminated fish or seafood. Other ECs produced either naturally or anthropogenically ultimately flow into marine waters. Pharmaceuticals are also an important pollution source, mostly due to overproduction and incorrect disposal. Ship breaking and recycle industries (SBRIs) can also release various pollutants and substantially deteriorate habitats and marine biodiversity. Overfishing is significantly increasing due to the global food crisis, caused by an increasing world population. Organic matter (OM) pollution and global warming (GW) are key factors that exacerbate these challenges (e.g. algal blooms), to which acidification in marine waters should be added as well. Sources, factors, mechanisms and possible remedial measures of these challenges to marine ecosystems are discussed, including their eventual impact on all forms of life including humans. -- Review of sources, factors, mechanisms and possible remedial measures of key pollutants (contaminants, toxins, ship breaking, overfishing) in marine ecosystems

Improving SWAT for simulating water and carbon fluxes of forest ecosystems

Energy Technology Data Exchange (ETDEWEB)

Yang, Qichun; Zhang, Xuesong

2016-11-01

As a widely used watershed model for assessing impacts of anthropogenic and natural disturbances on water quantity and quality, the Soil and Water Assessment Tool (SWAT) has not been extensively tested in simulating water and carbon fluxes of forest ecosystems. Here, we examine SWAT simulations of evapotranspiration (ET), net primary productivity (NPP), net ecosystem exchange (NEE), and plant biomass at ten AmeriFlux forest sites across the U.S. We identify unrealistic radiation use efficiency (Bio_E), large leaf to biomass fraction (Bio_LEAF), and missing phosphorus supply from parent material weathering as the primary causes for the inadequate performance of the default SWAT model in simulating forest dynamics. By further revising the relevant parameters and processes, SWAT’s performance is substantially improved. Based on the comparison between the improved SWAT simulations and flux tower observations, we discuss future research directions for further enhancing model parameterization and representation of water and carbon cycling for forests.

Nitrogen-limited mangrove ecosystems conserve N through dissimilatory nitrate reduction to ammonium.

Science.gov (United States)

Fernandes, Sheryl Oliveira; Bonin, Patricia C; Michotey, Valérie D; Garcia, Nicole; LokaBharathi, P A

2012-01-01

Earlier observations in mangrove sediments of Goa, India have shown denitrification to be a major pathway for N loss. However, percentage of total nitrate transformed through complete denitrification accounted for nitrate reduced. Here, we show that up to 99% of nitrate removal in mangrove sediments is routed through dissimilatory nitrate reduction to ammonium (DNRA). The DNRA process was 2x higher at the relatively pristine site Tuvem compared to the anthropogenically-influenced Divar mangrove ecosystem. In systems receiving low extraneous nutrient inputs, this mechanism effectively conserves and re-circulates N minimizing nutrient loss that would otherwise occur through denitrification. In a global context, the occurrence of DNRA in mangroves has important implications for maintaining N levels and sustaining ecosystem productivity. For the first time, this study also highlights the significance of DNRA in buffering the climate by modulating the production of the greenhouse gas nitrous oxide.

Exploratory analysis of atmospheric pollution in a coastal forest ecosystem in central Italy

Directory of Open Access Journals (Sweden)

Rita Aromolo

2015-02-01

Full Text Available Exploratory analysis of atmospheric pollution in a coastal forest ecosystem in central Italy - The study of spatial and temporal distribution of heavy metals in the atmosphere through the continuous assessment of deposition is of great interest for the analysis of anthropogenic pressure on the environment and the potential toxicity to humans and other living organisms. Information based on reliable estimates of heavy metals is therefore crucial for the evaluation of environmental quality. Trends in heavy metal concentration in atmospheric depositions on a coastal forest ecosystem (Castelporziano, Rome are analyzed in the present study based on a three-year monitoring field survey over three sites representative of different woodland characteristics in the area. Our results highlight both the influence of transportation processes in the short and medium distance based on the human pressure reflecting urban expansion and infrastructure development on the fringe of Castelporziano pristine forest. Further studies investigating the latent correlation with meteorological variables at various temporal scales are needed to provide a comprehensive picture of environmental conditions in a forest ecosystem subjected to increasing human pressure. Analysis of runoff water quality and the determination of other heavy metals, such as arsenic, may identify additional sources of pollution impacting soil and forest ecosystem.

Discriminating background from anthropogenic lead by isotopic methods

International Nuclear Information System (INIS)

Nelson, B.K.; O'Brien, H.E.

1995-01-01

The goal of this pilot project was to evaluate the practicality of using natural variations in the isotopic composition of lead to test for the presence of anthropogenic lead in soil, surface water and ground water. Complex chemical reactions in the environment may cause measured lead concentrations to be ambiguous indicators of anthropogenic lead component. The lead isotope tracer technique has the potential to identify both the presence and proportion of anthropogenic lead in the environment. The tested the lead isotope technique at Eielson Air Force Base, Alaska, on sources of suspected fuel contamination. Although the results are specific to this base, the general technique of using lead isotopes to trace the movement of anthropogenic lead is applicable to other CERCLA sites. The study had four objectives: (1) characterize the natural lead isotope composition of bedrock, stream sediment and soils; (2) characterize the isotopic composition of the contaminant lead derived from fuel; (3) evaluate the sensitivity of the isotopic method to distinguishing between anthropogenic and natural lead in soil and water samples and (4) evaluate the analytical feasibility and accuracy of the method at the Isotope Geochemistry Laboratory at the University of Washington

Cosmological perturbation theory and quantum gravity

Energy Technology Data Exchange (ETDEWEB)

Brunetti, Romeo [Dipartimento di Matematica, Università di Trento,Via Sommarive 14, 38123 Povo TN (Italy); Fredenhagen, Klaus [II Institute für Theoretische Physik, Universität Hamburg,Luruper Chaussee 149, 22761 Hamburg (Germany); Hack, Thomas-Paul [Institute für Theoretische Physik, Universität Leipzig,Brüderstr. 16, 04103 Leipzig (Germany); Pinamonti, Nicola [Dipartimento di Matematica, Università di Genova,Via Dodecaneso 35, 16146 Genova (Italy); INFN, Sezione di Genova,Via Dodecaneso 33, 16146 Genova (Italy); Rejzner, Katarzyna [Department of Mathematics, University of York,Heslington, York YO10 5DD (United Kingdom)

2016-08-04

It is shown how cosmological perturbation theory arises from a fully quantized perturbative theory of quantum gravity. Central for the derivation is a non-perturbative concept of gauge-invariant local observables by means of which perturbative invariant expressions of arbitrary order are generated. In particular, in the linearised theory, first order gauge-invariant observables familiar from cosmological perturbation theory are recovered. Explicit expressions of second order quantities are presented as well.

Intensive land use in the Swedish mountains between AD 800 and 1200 led to deforestation and ecosystem transformation with long-lasting effects.

Science.gov (United States)

Östlund, Lars; Hörnberg, Greger; DeLuca, Thomas H; Liedgren, Lars; Wikström, Peder; Zackrisson, Olle; Josefsson, Torbjörn

2015-10-01

Anthropogenic deforestation has shaped ecosystems worldwide. In subarctic ecosystems, primarily inhabited by native peoples, deforestation is generally considered to be mainly associated with the industrial period. Here we examined mechanisms underlying deforestation a thousand years ago in a high-mountain valley with settlement artifacts located in subarctic Scandinavia. Using the Heureka Forestry Decision Support System, we modeled pre-settlement conditions and effects of tree cutting on forest cover. To examine lack of regeneration and present nutrient status, we analyzed soil nitrogen. We found that tree cutting could have deforested the valley within some hundred years. Overexploitation left the soil depleted beyond the capacity of re-establishment of trees. We suggest that pre-historical deforestation has occurred also in subarctic ecosystems and that ecosystem boundaries were especially vulnerable to this process. This study improves our understanding of mechanisms behind human-induced ecosystem transformations and tree-line changes, and of the concept of wilderness in the Scandinavian mountain range.

Organic carbon sedimentation rates in Asian mangrove coastal ecosystems estimated by 210PB chronology

International Nuclear Information System (INIS)

Tateda, Y.; Wattayakorn, G.; Nhan, D.D.; Kasuya, Y.

2004-01-01

Organic carbon balance estimation of mangrove coastal ecosystem is important for understanding of Asian coastal carbon budget/flux calculation in global carbon cycle modelling which is powerful tool for the prediction of future greenhouse gas effect and evaluation of countermeasure preference. Especially, the organic carbon accumulation rate in mangrove ecosystem was reported to be important sink of carbon as well as that in boreal peat accumulation. For the estimation of 10 3 years scale organic carbon accumulation rates in mangrove coastal ecosystems, 14 C was used as long term chronological tracer, being useful in pristine mangrove forest reserve area. While in case of mangrove plantation of in coastal area, the 210 Pb is suitable for the estimation of decades scale estimation by its half-life. Though it has possibility of bio-/physical- turbation effect in applying 210 Pb chronology that is offset in case of 10 3 years scale estimation, especially in Asian mangrove ecosystem where the anthropogenic physical turbation by coastal fishery is vigorous.In this paper, we studied the organic carbon and 210 Pb accumulation rates in subtropical mangrove coastal ecosystems in Japan, Vietnam and Thailand with 7 Be analyses to make sure the negligible effect of above turbation effects on organic carbon accumulation. We finally concluded that 210 Pb was applicable to estimate organic carbon accumulation rates in these ecosystems even though the physical-/bio-turbation is expected. The measured organic carbon accumulation rates using 210 Pb in mangrove coastal ecosystems of Japan, Vietnam and Thailand were 0.067 4.0 t-C ha -1 y -1 . (author)

Perturbations i have Known and Loved

Science.gov (United States)

Field, Robert W.

2011-06-01

A spectroscopic perturbation is a disruption of a ^1Σ-^1Σ-like regular pattern that can embody level-shifts, extra lines, and intensity anomalies. Once upon a time, when a band was labeled ``perturbed,'' it was considered worthless because it could at best yield molecular constants unsuited for archival tables. Nevertheless, a few brave spectroscopists, notably Albin Lagerqvist and Richard Barrow, collected perturbations because they knew that the pattern of multiple perturbations formed an intricate puzzle that would eventually reveal the presence and electronic symmetry of otherwise unobservable electronic states. There are many kinds of patterns of broken patterns. In my PhD thesis I showed how to determine absolute vibrational assignments for the perturber from patterns among the observed values of perturbation matrix elements. When a ^3Π state is perturbed, its six (Ω, parity) components capture a pattern of level shifts and intensity anomalies that reveals more about the nature of the perturber than a simple perturbation of the single component of a ^1Σ state. In perturbation-facilitated OODR, a perturbed singlet level acts as a spectroscopic doorway through which the entire triplet manifold may be systematically explored. For polyatomic molecule vibrations, a vibrational polyad (a group of mutually perturbing vibrational levels, among which the perturbation matrix elements are expected to follow harmonic oscillator scaling rules) can contain more components than a ^3Π state and intrapolyad patterns can be exquisitely sensitive not merely to the nature of an interloper within the polyad but also to the eigenvector character of the vibronic state from which the polyad is viewed. Variation of scaled polyad interaction parameters from one polyad to the next, a pattern of patterns, can signal proximity to an isomerization barrier. Everything in Rydberg-land seems to scale as N⋆-3, yet a trespassing valence state causes all scaling and propensity rules go

87Sr/86Sr and 143Nd/144Nd for disentangling anthropogenic and natural REE contributions in river water during flood events.

Science.gov (United States)

Hissler, Christophe; Stille, Peter; Pfister, Laurent

2017-04-01

The sustainable management of water resources is one of the greatest challenges of the 21st century. Water is a vital resource that is increasingly put under pressure from multiple perspectives. While the global population is on the rise, socio-economic development makes equally rapid progress - eventually compromising access to clean water bodies. Multiple pollution sources constitute an immediate threat to aquatic ecosystems and are likely to cause long lasting contaminations of water bodies that are critical for drinking and/or irrigation water production. There is a pressing need for an adequate quantification of anthropogenic impacts on the critical zone of river basins and the identification of the temporal dynamics of these impacts. As an example, despite the work done to assess the environmental impact of REE pollutions in larger river systems, we are still lacking information on the dynamics of these anthropogenic compounds in relation to rapid hydrological changes. Filling these knowledge gaps is a pre-requisite for the design and implementation of sustainable water resources management strategies. In order to better constrain the relative contributions of both anthropogenic and geogenic trace element sources we propose using a multitracer approach combining elemental and 87Sr/86Sr, 143Nd/144Nd, and 206Pb/207Pb isotopic ratios. The use of these three separate isotopic systems together with REE concentrations is new in the field of anthropogenic source identification in river systems. We observed enrichments in Anthropogenic Rare Earth Elements (AREE) for dissolved Gd and suspended Nd loads of river water. With increasing discharge, AREE anomalies progressively disappeared and gave way to the geogenic chemical signature of the basin in both dissolved and suspended loads. The isotopic data confirm these observations and shed new light on the trace elements sources. On the one hand, dissolved loads have peculiar isotopic characteristics and carry mainly

Climatic impacts of anthropogenic aerosols

Energy Technology Data Exchange (ETDEWEB)

Iversen, T. [Oslo Univ. (Norway)

1996-03-01

This paper was read at the workshop ``The Norwegian Climate and Ozone Research Programme`` held on 11-12 March 1996. Anthropogenic production of aerosols is mainly connected with combustion of fossil fuel. Measured by particulate mass, the anthropogenic sulphate production is the dominating source of aerosols in the Northern Hemisphere. Particles emitted in mechanical processes, fly ash etc. are less important because of their shorter atmospheric residence time. Possible climatological effects of anthropogenic aerosols are usually classified in two groups: direct and indirect. Direct effects are alterations of the radiative heating budget due to the aerosol particles in clear air. Indirect effects involve the interaction between particles and cloud processes. A simplified one-layer radiation model gave cooling in the most polluted mid-latitude areas and heating due to soot absorption in the Arctic. This differential trend in heating rates may have significant effects on atmospheric meridional circulations, which is important for the atmosphere as a thermodynamic system. Recently the description of sulphur chemistry in the hemispheric scale dispersion model has been improved and will be used in a model for Mie scattering and absorption

Gridded anthropogenic emissions inventory and atmospheric transport of carbonyl sulfide in the U.S.: U.S. Anthropogenic COS Source and Transport

Energy Technology Data Exchange (ETDEWEB)

Zumkehr, Andrew [Sierra Nevada Research Institute, University of California, Merced California USA; Hilton, Timothy W. [Sierra Nevada Research Institute, University of California, Merced California USA; Whelan, Mary [Sierra Nevada Research Institute, University of California, Merced California USA; Smith, Steve [Joint Global Change Research Institute, PNNL, College Park Maryland USA; Campbell, J. Elliott [Sierra Nevada Research Institute, University of California, Merced California USA

2017-02-21

Carbonyl sulfide (COS or OCS), the most abundant sulfur containing gas in the troposphere, has recently emerged as a potentially important atmospheric tracer for the carbon cycle. Atmospheric inverse modeling studies may be able to use existing tower, airborne, and satellite observations of COS to infer information about photosynthesis. However, such analysis relies on gridded anthropogenic COS source estimates that are largely based on industry activity data from over three decades ago. Here we use updated emission factor data and industry activity data to develop a gridded inventory with a 0.1 degree resolution for the U.S. domain. The inventory includes the primary anthropogenic COS sources including direct emissions from the coal and aluminum industries as well as indirect sources from industrial carbon disulfide emissions. Compared to the previously published inventory, we found that the total anthropogenic source (direct and indirect) is 47% smaller. Using this new gridded inventory to drive the STEM/WRF atmospheric transport model, we found that the anthropogenic contribution to COS variation in the troposphere is small relative to the biosphere influence, which is encouraging of carbon cycle applications in this region. Additional anthropogenic sectors with highly uncertain emission factors require further field measurements.

Influence of Holocene environmental change and anthropogenic impact on the diversity and distribution of roe deer.

Science.gov (United States)

Baker, K H; Hoelzel, A R

2014-06-01

Extant patterns of population structure and levels of diversity are a consequence of factors that vary in both space and time. Our objective in this study is to investigate a species that has responded to both natural and anthropogenic changes in ways that have shaped modern populations and provide insight into the key processes. The roe deer (Capreolus capreolus) is one of the two species of deer native to Britain. During the last glacial maximum (LGM), the British habitat was largely under ice and there was a land bridge to mainland Europe. As the Earth warmed during the early Holocene, the land bridge was lost. Subsequent hunting on the British mainland left the southern region extirpated of roe deer, whereas a refugial population remained in the north. Later reintroductions from Europe led to population expansion, especially in southern United Kingdom. Here, we combine data from ancient and modern DNA to track population dynamics and patterns of connectivity, and test hypotheses about the influence of natural and anthropogenic environmental change. We find that past expansion and divergence events coincided with a warming environment and the subsequent closure of the land bridge between Europe and the United Kingdom. We also find turnover in British roe deer haplotypes between the late-Holocene and modern day that have likely resulted from recent human disturbance activities such as habitat perturbation, overhunting and restocking.

Drought resistance across California ecosystems: Evaluating changes in carbon dynamics using satellite imagery

Science.gov (United States)

Malone, Sparkle; Tulbure, Mirela; Pérez-Luque, Antonio J.; Assal, Timothy J.; Bremer, Leah; Drucker, Debora; Hillis, Vicken; Varela, Sara; Goulden, Michael

2016-01-01

Drought is a global issue that is exacerbated by climate change and increasing anthropogenic water demands. The recent occurrence of drought in California provides an important opportunity to examine drought response across ecosystem classes (forests, shrublands, grasslands, and wetlands), which is essential to understand how climate influences ecosystem structure and function. We quantified ecosystem resistance to drought by comparing changes in satellite-derived estimates of water-use efficiency (WUE = net primary productivity [NPP]/evapotranspiration [ET]) under normal (i.e., baseline) and drought conditions (ΔWUE = WUE2014 − baseline WUE). With this method, areas with increasing WUE under drought conditions are considered more resilient than systems with declining WUE. Baseline WUE varied across California (0.08 to 3.85 g C/mm H2O) and WUE generally increased under severe drought conditions in 2014. Strong correlations between ΔWUE, precipitation, and leaf area index (LAI) indicate that ecosystems with a lower average LAI (i.e., grasslands) also had greater C-uptake rates when water was limiting and higher rates of carbon-uptake efficiency (CUE = NPP/LAI) under drought conditions. We also found that systems with a baseline WUE ≤ 0.4 exhibited a decline in WUE under drought conditions, suggesting that a baseline WUE ≤ 0.4 might be indicative of low drought resistance. Drought severity, precipitation, and WUE were identified as important drivers of shifts in ecosystem classes over the study period. These findings have important implications for understanding climate change effects on primary productivity and C sequestration across ecosystems and how this may influence ecosystem resistance in the future.

Characterization of soil fauna under the influence of mercury atmospheric deposition in Atlantic Forest, Rio de Janeiro, Brazil.

Science.gov (United States)

Buch, Andressa Cristhy; Correia, Maria Elizabeth Fernandes; Teixeira, Daniel Cabral; Silva-Filho, Emmanoel Vieira

2015-06-01

The increasing levels of mercury (Hg) found in the atmosphere arising from anthropogenic sources, have been the object of great concern in the past two decades in industrialized countries. Brazil is the seventh country with the highest rate of mercury in the atmosphere. The major input of Hg to ecosystems is through atmospheric deposition (wet and dry), being transported in the atmosphere over large distances. The forest biomes are of strong importance in the atmosphere/soil cycling of elemental Hg through foliar uptake and subsequent transference to the soil through litter, playing an important role as sink of this element. Soil microarthropods are keys to understanding the soil ecosystem, and for such purpose were characterized by the soil fauna of two Units of Forest Conservation of the state of the Rio de Janeiro, inwhich one of the areas suffer quite interference from petrochemicals and industrial anthropogenic activities and other area almost exempts of these perturbations. The results showed that soil and litter of the Atlantic Forest in Brazil tend to stock high mercury concentrations, which could affect the abundance and richness of soil fauna, endangering its biodiversity and thereby the functioning of ecosystems. Copyright © 2015. Published by Elsevier B.V.

Function of Wildfire-Deposited Pyrogenic Carbon in Terrestrial Ecosystems

Directory of Open Access Journals (Sweden)

Melissa R. A. Pingree

2017-08-01

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

Mechanisms and risk of cumulative impacts to coastal ecosystem services: An expert elicitation approach.

Science.gov (United States)

Singh, Gerald G; Sinner, Jim; Ellis, Joanne; Kandlikar, Milind; Halpern, Benjamin S; Satterfield, Terre; Chan, Kai M A

2017-09-01

Coastal environments are some of the most populated on Earth, with greater pressures projected in the future. Managing coastal systems requires the consideration of multiple uses, which both benefit from and threaten multiple ecosystem services. Thus understanding the cumulative impacts of human activities on coastal ecosystem services would seem fundamental to management, yet there is no widely accepted approach for assessing these. This study trials an approach for understanding the cumulative impacts of anthropogenic change, focusing on Tasman and Golden Bays, New Zealand. Using an expert elicitation procedure, we collected information on three aspects of cumulative impacts: the importance and magnitude of impacts by various activities and stressors on ecosystem services, and the causal processes of impact on ecosystem services. We assessed impacts to four ecosystem service benefits - fisheries, shellfish aquaculture, marine recreation and existence value of biodiversity-addressing three main research questions: (1) how severe are cumulative impacts on ecosystem services (correspondingly, what potential is there for restoration)?; (2) are threats evenly distributed across activities and stressors, or do a few threats dominate?; (3) do prominent activities mainly operate through direct stressors, or do they often exacerbate other impacts? We found (1) that despite high uncertainty in the threat posed by individual stressors and impacts, total cumulative impact is consistently severe for all four ecosystem services. (2) A subset of drivers and stressors pose important threats across the ecosystem services explored, including climate change, commercial fishing, sedimentation and pollution. (3) Climate change and commercial fishing contribute to prominent indirect impacts across ecosystem services by exacerbating regional impacts, namely sedimentation and pollution. The prevalence and magnitude of these indirect, networked impacts highlights the need for approaches

Mechanisms and risk of cumulative impacts to coastal ecosystem services: An expert elicitation approach

KAUST Repository

Singh, Gerald G.

2017-05-23

Coastal environments are some of the most populated on Earth, with greater pressures projected in the future. Managing coastal systems requires the consideration of multiple uses, which both benefit from and threaten multiple ecosystem services. Thus understanding the cumulative impacts of human activities on coastal ecosystem services would seem fundamental to management, yet there is no widely accepted approach for assessing these. This study trials an approach for understanding the cumulative impacts of anthropogenic change, focusing on Tasman and Golden Bays, New Zealand. Using an expert elicitation procedure, we collected information on three aspects of cumulative impacts: the importance and magnitude of impacts by various activities and stressors on ecosystem services, and the causal processes of impact on ecosystem services. We assessed impacts to four ecosystem service benefits — fisheries, shellfish aquaculture, marine recreation and existence value of biodiversity—addressing three main research questions: (1) how severe are cumulative impacts on ecosystem services (correspondingly, what potential is there for restoration)?; (2) are threats evenly distributed across activities and stressors, or do a few threats dominate?; (3) do prominent activities mainly operate through direct stressors, or do they often exacerbate other impacts? We found (1) that despite high uncertainty in the threat posed by individual stressors and impacts, total cumulative impact is consistently severe for all four ecosystem services. (2) A subset of drivers and stressors pose important threats across the ecosystem services explored, including climate change, commercial fishing, sedimentation and pollution. (3) Climate change and commercial fishing contribute to prominent indirect impacts across ecosystem services by exacerbating regional impacts, namely sedimentation and pollution. The prevalence and magnitude of these indirect, networked impacts highlights the need for

Variations of Ecosystem Service Value in Response to Land-Use Change in the Kashgar Region, Northwest China

Directory of Open Access Journals (Sweden)

Aynur Mamat

2018-01-01

Full Text Available Increasing anthropogenic activities have significantly altered ecosystems in arid oasis regions. Estimating the impact on a wide range of ecosystem services is important for decision making and the sustainable development of these regions. This study analyzed time-series Landsat data to determine the influences of oasis land-use changes on the ecosystem services in the Kashgar region in Northwest China. The following results were found. The total value of the ecosystem services in the Kashgar region were approximately $10,845.3, $11,218.6, $10,291.7, and $10,127.3 million in 1986, 1996, 2005, and 2015, respectively. The water supply, waste treatment, biodiversity protection, and recreation and cultural services were the four ecosystem services with the highest service value, contributing 77.05% of the total ecosystem services. The combined contribution rate of food production and raw material value was only about 4.02%, relatively small. The sensitivity analysis indicated that the estimated total ecosystem service value (ESV for this study area was relatively inelastic with respect to the value coefficients. The findings of this study will be crucial for maintaining the stability and sustainable development of the oasis region, where socio-economic development and the integrity of the natural ecosystem complement each other. Furthermore, the results provide a scientific basis for decision makers in land use management, and provide a reference for researchers in the Northwest China.

The Baltic Sea as a time machine for the future coastal ocean

DEFF Research Database (Denmark)

Reusch, Thorsten B. H.; Dierking, Jan; Andersson, Helen C.

2018-01-01

the efficacy of management actions to address the breakdown of ecosystem functions. Trend reversals such as the return of top predators, recovering fish stocks, and reduced input of nutrient and harmful substances could be achieved only by implementing an international, cooperative governance structure....... This situation calls for management that is (i) conservative to provide a buffer against regionally unmanageable global perturbations, (ii) adaptive to react to new management challenges, and, ultimately, (iii) multisectorial and integrative to address conflicts associated with economic trade-offs.......Coastal global oceans are expected to undergo drastic changes driven by climate change and increasing anthropogenic pressures in coming decades. Predicting specific future conditions and assessing the best management strategies to maintain ecosystem integrity and sustainable resource use...

Millennium Ecosystem Assessment: MA Ecosystems

Data.gov (United States)

National Aeronautics and Space Administration — The Millennium Ecosystem Assessment: MA Ecosystems provides data and information on the extent and classification of ecosystems circa 2000, including coastal,...

Optimal random perturbations for stochastic approximation using a simultaneous perturbation gradient approximation

DEFF Research Database (Denmark)

Sadegh, Payman; Spall, J. C.

1998-01-01

simultaneous perturbation approximation to the gradient based on loss function measurements. SPSA is based on picking a simultaneous perturbation (random) vector in a Monte Carlo fashion as part of generating the approximation to the gradient. This paper derives the optimal distribution for the Monte Carlo...

From nitrogen enrichment to oxygen depletion: a mechanistic model of coastal marine ecosystems response

DEFF Research Database (Denmark)

Cosme, Nuno Miguel Dias; Koski, Marja; Hauschild, Michael Zwicky

Nitrogen (N) emissions from anthropogenic sources may enrich coastal waters and lead to marine eutrophication impacts. Processes describing N-limited primary production (PP), zooplankton grazing, and bacterial respiration of sinking organic carbon, were modelled to quantify the potential dissolved...... oxygen (DO) consumption as a function of N input. Such indicator is the basis for an eXposure Factor (XF) applied in Life Cycle Impact Assessment (LCIA) to estimate impacts from N enrichment. The Large Marine Ecosystems (LME) biogeographical classification system was adopted to address the spatial...

Disformal transformation of cosmological perturbations

Directory of Open Access Journals (Sweden)

Masato Minamitsuji

2014-10-01

Full Text Available We investigate the gauge-invariant cosmological perturbations in the gravity and matter frames in the general scalar–tensor theory where two frames are related by the disformal transformation. The gravity and matter frames are the extensions of the Einstein and Jordan frames in the scalar–tensor theory where two frames are related by the conformal transformation, respectively. First, it is shown that the curvature perturbation in the comoving gauge to the scalar field is disformally invariant as well as conformally invariant, which gives the predictions from the cosmological model where the scalar field is responsible both for inflation and cosmological perturbations. Second, in case that the disformally coupled matter sector also contributes to curvature perturbations, we derive the evolution equations of the curvature perturbation in the uniform matter energy density gauge from the energy (nonconservation in the matter sector, which are independent of the choice of the gravity sector. While in the matter frame the curvature perturbation in the uniform matter energy density gauge is conserved on superhorizon scales for the vanishing nonadiabatic pressure, in the gravity frame it is not conserved even if the nonadiabatic pressure vanishes. The formula relating two frames gives the amplitude of the curvature perturbation in the matter frame, once it is evaluated in the gravity frame.

Disformal transformation of cosmological perturbations

International Nuclear Information System (INIS)

Minamitsuji, Masato

2014-01-01

We investigate the gauge-invariant cosmological perturbations in the gravity and matter frames in the general scalar–tensor theory where two frames are related by the disformal transformation. The gravity and matter frames are the extensions of the Einstein and Jordan frames in the scalar–tensor theory where two frames are related by the conformal transformation, respectively. First, it is shown that the curvature perturbation in the comoving gauge to the scalar field is disformally invariant as well as conformally invariant, which gives the predictions from the cosmological model where the scalar field is responsible both for inflation and cosmological perturbations. Second, in case that the disformally coupled matter sector also contributes to curvature perturbations, we derive the evolution equations of the curvature perturbation in the uniform matter energy density gauge from the energy (non)conservation in the matter sector, which are independent of the choice of the gravity sector. While in the matter frame the curvature perturbation in the uniform matter energy density gauge is conserved on superhorizon scales for the vanishing nonadiabatic pressure, in the gravity frame it is not conserved even if the nonadiabatic pressure vanishes. The formula relating two frames gives the amplitude of the curvature perturbation in the matter frame, once it is evaluated in the gravity frame

Preheating curvaton perturbations

International Nuclear Information System (INIS)

Bastero-Gil, M.; Di Clemente, V.; King, S.F.

2005-01-01

We discuss the potentially important role played by preheating in certain variants of the curvaton mechanism in which isocurvature perturbations of a D-flat (and F-flat) direction become converted to curvature perturbations during reheating. We discover that parametric resonance of the isocurvature components amplifies the superhorizon fluctuations by a significant amount. As an example of these effects we develop a particle physics motivated model which involves hybrid inflation with the waterfall field N being responsible for generating the μ term, the right-handed neutrino mass scale, and the Peccei-Quinn symmetry breaking scale. The role of the curvaton field can be played either by usual Higgs field, or the lightest right-handed sneutrino. Our new results show that it is possible to achieve the correct curvature perturbations for initial values of the curvaton fields of order the weak scale. In this model we show that the prediction for the spectral index of the final curvature perturbation only depends on the mass of the curvaton during inflation, where consistency with current observational data requires the ratio of this mass to the Hubble constant to be 0.3

Establishing an anthropogenic nitrogen baseline using Native American shell middens

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Autumn eOczkowski

2016-05-01

Full Text Available Narragansett Bay, Rhode Island, has been heavily influenced by anthropogenic nutrients for more than 200 years. Recent efforts to improve water quality have cut sewage nitrogen (N loads to this point source estuary by more than half. Given that the bay has been heavily fertilized for longer than monitoring programs have been in place, we sought additional insight into how N dynamics in the system have historically changed. To do this, we measured the N stable isotope (δ15N values in clam shells from as early as 3000 BP to the present. Samples from Native American middens were compared with those collected locally from museums, an archaeological company, and graduate student thesis projects, during a range of time periods. Overall, δ15N values in clam shells from Narragansett Bay have increased significantly over time, reflecting known patterns of anthropogenic nutrient enrichment. Pre-colonization midden shell δ15N values were significantly lower than those post-European contact. While there were no statistical differences among shells dated from the late 15th Century to 2005, there was a significant difference between 2005 and 2015 shells, which we attribute to the higher δ15N values in the effluent associated with recent sewage treatment upgrades. In contrast, the δ15N values of shells from the southern Rhode Island coast remained constant through time; while influenced by human activities, these areas are not directly influenced by point-source sewage discharge. Overall, our results show that this isotope technique for measuring δ15N values in clam shells provides useful insight into how N dynamics in coastal ecosystems have changed during thousands of years, providing managers vital historical information when setting goals for N reduction.

Nutrient Budgets Calculated in Floodwaters Using a Whole-Ecosystem Experimental Manipulation

Science.gov (United States)

Talbot, C. J.; Paterson, M. J.; Xenopoulos, M. A.

2017-12-01

Flooding provides pathways for nutrients to move into surface waters and alter nutrient concentrations, therefore influencing downstream ecosystems and increasing events of eutrophication. Nutrient enrichment will likely affect water quality, primary production, and overall ecosystem function. Quantifying nutrient movement post-flood will help evaluate the risks or advantages that flooding will have on ecosystem processes. Here we constructed nutrient budgets using data collected as part of the Flooded Upland Dynamics Experiment (FLUDEX) at the Experimental Lakes Area (ELA) in northwestern Ontario. Three experimental reservoirs with varying amounts of stored carbon were created by flooding forested land from May through September annually from 1999 to 2003. Organic matter became a significant source of nutrients under flooded conditions and elevated reservoir total nitrogen (TN) and total phosphorus (TP) concentrations within one week of flooding. The highest TN (2.6 mg L-1) and TP (579 µg L-1) concentrations throughout the entire flooding experiment occurred in the medium carbon reservoir within the first two weeks of flooding in 1999. TN and TP fluxes were positive in all years of flooding. TP fluxes decreased after each flooding season therefore, TP production may be less problematic in floodplains subject to frequent repeated flooding. However, TN fluxes remained large even after repeated flooding. Therefore, flooding, whether naturally occurring or from anthropogenic flow alteration, may be responsible for producing significant amounts of nitrogen and phosphorus in aquatic ecosystems.

Responses of ecosystem nitrogen cycle to nitrogen addition: a meta-analysis.

Science.gov (United States)

Lu, Meng; Yang, Yuanhe; Luo, Yiqi; Fang, Changming; Zhou, Xuhui; Chen, Jiakuan; Yang, Xin; Li, Bo

2011-03-01

• Anthropogenic nitrogen (N) addition may substantially alter the terrestrial N cycle. However, a comprehensive understanding of how the ecosystem N cycle responds to external N input remains elusive. • Here, we evaluated the central tendencies of the responses of 15 variables associated with the ecosystem N cycle to N addition, using data extracted from 206 peer-reviewed papers. • Our results showed that the largest changes in the ecosystem N cycle caused by N addition were increases in soil inorganic N leaching (461%), soil NO₃⁻ concentration (429%), nitrification (154%), nitrous oxide emission (134%), and denitrification (84%). N addition also substantially increased soil NH₄+ concentration (47%), and the N content in belowground (53%) and aboveground (44%) plant pools, leaves (24%), litter (24%) and dissolved organic N (21%). Total N content in the organic horizon (6.1%) and mineral soil (6.2%) slightly increased in response to N addition. However, N addition induced a decrease in microbial biomass N by 5.8%. • The increases in N effluxes caused by N addition were much greater than those in plant and soil pools except soil NO₃⁻, suggesting a leaky terrestrial N system. © 2010 The Authors. New Phytologist © 2010 New Phytologist Trust.

Establishing research strategies, methodologies and technologies to link genomics and proteomics to seagrass productivity, community metabolism, and ecosystem carbon fluxes.

Science.gov (United States)

Mazzuca, Silvia; Björk, M; Beer, S; Felisberto, P; Gobert, S; Procaccini, G; Runcie, J; Silva, J; Borges, A V; Brunet, C; Buapet, P; Champenois, W; Costa, M M; D'Esposito, D; Gullström, M; Lejeune, P; Lepoint, G; Olivé, I; Rasmusson, L M; Richir, J; Ruocco, M; Serra, I A; Spadafora, A; Santos, Rui

2013-01-01

A complete understanding of the mechanistic basis of marine ecosystem functioning is only possible through integrative and interdisciplinary research. This enables the prediction of change and possibly the mitigation of the consequences of anthropogenic impacts. One major aim of the European Cooperation in Science and Technology (COST) Action ES0609 "Seagrasses productivity. From genes to ecosystem management," is the calibration and synthesis of various methods and the development of innovative techniques and protocols for studying seagrass ecosystems. During 10 days, 20 researchers representing a range of disciplines (molecular biology, physiology, botany, ecology, oceanography, and underwater acoustics) gathered at The Station de Recherches Sous-marines et Océanographiques (STARESO, Corsica) to study together the nearby Posidonia oceanica meadow. STARESO is located in an oligotrophic area classified as "pristine site" where environmental disturbances caused by anthropogenic pressure are exceptionally low. The healthy P. oceanica meadow, which grows in front of the research station, colonizes the sea bottom from the surface to 37 m depth. During the study, genomic and proteomic approaches were integrated with ecophysiological and physical approaches with the aim of understanding changes in seagrass productivity and metabolism at different depths and along daily cycles. In this paper we report details on the approaches utilized and we forecast the potential of the data that will come from this synergistic approach not only for P. oceanica but for seagrasses in general.

Anthropogenic noise compromises antipredator behaviour in European eels.

Science.gov (United States)

Simpson, Stephen D; Purser, Julia; Radford, Andrew N

2015-02-01

Increases in noise-generating human activities since the Industrial Revolution have changed the acoustic landscape of many terrestrial and aquatic ecosystems. Anthropogenic noise is now recognized as a major pollutant of international concern, and recent studies have demonstrated impacts on, for instance, hearing thresholds, communication, movement and foraging in a range of species. However, consequences for survival and reproductive success are difficult to ascertain. Using a series of laboratory-based experiments and an open-water test with the same methodology, we show that acoustic disturbance can compromise antipredator behaviour--which directly affects survival likelihood--and explore potential underlying mechanisms. Juvenile European eels (Anguilla anguilla) exposed to additional noise (playback of recordings of ships passing through harbours), rather than control conditions (playback of recordings from the same harbours without ships), performed less well in two simulated predation paradigms. Eels were 50% less likely and 25% slower to startle to an 'ambush predator' and were caught more than twice as quickly by a 'pursuit predator'. Furthermore, eels experiencing additional noise had diminished spatial performance and elevated ventilation and metabolic rates (indicators of stress) compared with control individuals. Our results suggest that acoustic disturbance could have important physiological and behavioural impacts on animals, compromising life-or-death responses. © 2014 John Wiley & Sons Ltd.

Critical research needs for identifying future changes in Gulf coral reef ecosystems

KAUST Repository

Feary, David A.

2013-07-01

Expert opinion was assessed to identify current knowledge gaps in determining future changes in Arabian/Persian Gulf (thereafter \\'Gulf\\') coral reefs. Thirty-one participants submitted 71 research questions that were peer-assessed in terms of scientific importance (i.e., filled a knowledge gap and was a research priority) and efficiency in resource use (i.e., was highly feasible and ecologically broad). Ten research questions, in six major research areas, were highly important for both understanding Gulf coral reef ecosystems and also an efficient use of limited research resources. These questions mirrored global evaluations of the importance of understanding and evaluating biodiversity, determining the potential impacts of climate change, the role of anthropogenic impacts in structuring coral reef communities, and economically evaluating coral reef communities. These questions provide guidance for future research on coral reef ecosystems within the Gulf, and enhance the potential for assessment and management of future changes in this globally significant region. © 2013 Elsevier Ltd.

Critical research needs for identifying future changes in Gulf coral reef ecosystems

Science.gov (United States)

Feary, David A.; Burt, John A.; Bauman, Andrew G.; Al Hazeem, Shaker; Abdel-Moati, Mohamed A.; Al-Khalifa, Khalifa A.; Anderson, Donald M.; Amos, Carl; Baker, Andrew; Bartholomew, Aaron; Bento, Rita; Cavalcante, Geórgenes H.; Chen, Chaolun Allen; Coles, Steve L.; Dab, Koosha; Fowler, Ashley M.; George, David; Grandcourt, Edwin; Hill, Ross; John, David M.; Jones, David A.; Keshavmurthy, Shashank; Mahmoud, Huda; Moradi Och Tapeh, Mahdi; Mostafavi, Pargol Ghavam; Naser, Humood; Pichon, Michel; Purkis, Sam; Riegl, Bernhard; Samimi-Namin, Kaveh; Sheppard, Charles; Vajed Samiei, Jahangir; Voolstra, Christian R.; Wiedenmann, Joerg

2014-01-01

Expert opinion was assessed to identify current knowledge gaps in determining future changes in Arabian/ Persian Gulf (thereafter ‘Gulf’) coral reefs. Thirty-one participants submitted 71 research questions that were peer-assessed in terms of scientific importance (i.e., filled a knowledge gap and was a research priority) and efficiency in resource use (i.e., was highly feasible and ecologically broad). Ten research questions, in six major research areas, were highly important for both understanding Gulf coral reef ecosystems and also an efficient use of limited research resources. These questions mirrored global evaluations of the importance of understanding and evaluating biodiversity, determining the potential impacts of climate change, the role of anthropogenic impacts in structuring coral reef communities, and economically evaluating coral reef communities. These questions provide guidance for future research on coral reef ecosystems within the Gulf, and enhance the potential for assessment and management of future changes in this globally significant region. PMID:23643407

Critical research needs for identifying future changes in Gulf coral reef ecosystems

KAUST Repository

Feary, David A.; Burt, John A.; Bauman, Andrew G.; Al Hazeem, Shaker; Abdel-Moati, Mohamed A R; Al-Khalifa, Khalifa A.; Anderson, Donald M.; Amos, Carl L.; Baker, Andrew C.; Bartholomew, Aaron; Bento, Rita; Cavalcante, Geó rgenes H.; Chen, Chaolun Allen; Coles, Steve L.; Dab, Koosha; Fowler, Ashley M.; George, David Glen; Grandcourt, Edwin Mark; Hill, Ross; John, David Michael; Jones, David Alan; Keshavmurthy, Shashank; Mahmoud, Huda M A; Moradi Och Tapeh, Mahdi; Mostafavi, Pargol Ghavam; Naser, Humood A.; Pichon, Michel; Purkis, Sam J.; Riegl, Bernhard M.; Samimi-Namin, Kaveh; Sheppard, Charles R C; Vajed Samiei, Jahangir; Voolstra, Christian R.; Wiedenmann, Jö rg

2013-01-01

Expert opinion was assessed to identify current knowledge gaps in determining future changes in Arabian/Persian Gulf (thereafter 'Gulf') coral reefs. Thirty-one participants submitted 71 research questions that were peer-assessed in terms of scientific importance (i.e., filled a knowledge gap and was a research priority) and efficiency in resource use (i.e., was highly feasible and ecologically broad). Ten research questions, in six major research areas, were highly important for both understanding Gulf coral reef ecosystems and also an efficient use of limited research resources. These questions mirrored global evaluations of the importance of understanding and evaluating biodiversity, determining the potential impacts of climate change, the role of anthropogenic impacts in structuring coral reef communities, and economically evaluating coral reef communities. These questions provide guidance for future research on coral reef ecosystems within the Gulf, and enhance the potential for assessment and management of future changes in this globally significant region. © 2013 Elsevier Ltd.

Isotopic fingerprints of anthropogenic molybdenum in lake sediments.

Science.gov (United States)

Chappaz, Anthony; Lyons, Timothy W; Gordon, Gwyneth W; Anbar, Ariel D

2012-10-16

We measured the molybdenum isotope compositions (δ(98)Mo) of well-dated sediment cores from two lakes in eastern Canada in an effort to distinguish between natural and anthropogenic contributions to these freshwater aquatic systems. Previously, Chappaz et al. (1) ascribed pronounced 20th-century Mo concentration enrichments in these lakes to anthropogenic inputs. δ(98)Mo values in the deeper sediments (reflecting predominantly natural Mo sources) differ dramatically between the two lakes: -0.32 ± 0.17‰ for oxic Lake Tantare and +0.64 ± 0.09‰ for anoxic Lake Vose. Sediment layers previously identified as enriched in anthropogenic Mo, however, reveal significant δ(98)Mo shifts of ± 0.3‰, resulting in isotopically heavier values of +0.05 ± 0.18‰ in Lake Tantare and lighter values of +0.31 ± 0.03‰ in Lake Vose. We argue that anthropogenic Mo modifies the isotopic composition of the recent sediments, and we determine δ(98)Mo(anthropogenic) values of 0.1 ± 0.1‰ (Lake Vose) and 0.2 ± 0.2‰ (Lake Tantare). These calculated inputs are consistent with the δ(98)Mo of molybdenite (MoS(2)) likely delivered to the lakes via smelting of porphyry copper deposits (Lake Vose) or through combustion of coal and oil also containing Mo (Lake Tantare). Our results confirm the utility of Mo isotopes as a promising fingerprint of human impacts and perhaps the specific sources of contamination. Importantly, the magnitudes of the anthropogenic inputs are large enough, relative to the natural Mo cycles in each lake, to have an impact on the microbiological communities.

Ecosystem variability in the offshore northeastern Chukchi Sea

Science.gov (United States)

Blanchard, Arny L.; Day, Robert H.; Gall, Adrian E.; Aerts, Lisanne A. M.; Delarue, Julien; Dobbins, Elizabeth L.; Hopcroft, Russell R.; Questel, Jennifer M.; Weingartner, Thomas J.; Wisdom, Sheyna S.

2017-12-01

Understanding influences of cumulative effects from multiple stressors in marine ecosystems requires an understanding of the sources for and scales of variability. A multidisciplinary ecosystem study in the offshore northeastern Chukchi Sea during 2008-2013 investigated the variability of the study area's two adjacent sub-ecosystems: a pelagic system influenced by interannual and/or seasonal temporal variation at large, oceanographic (regional) scales, and a benthic-associated system more influenced by small-scale spatial variations. Variability in zooplankton communities reflected interannual oceanographic differences in waters advected northward from the Bering Sea, whereas variation in benthic communities was associated with seafloor and bottom-water characteristics. Variations in the planktivorous seabird community were correlated with prey distributions, whereas interaction effects in ANOVA for walruses were related to declines of sea-ice. Long-term shifts in seabird distributions were also related to changes in sea-ice distributions that led to more open water. Although characteristics of the lower trophic-level animals within sub-ecosystems result from oceanographic variations and interactions with seafloor topography, distributions of apex predators were related to sea-ice as a feeding platform (walruses) or to its absence (i.e., open water) for feeding (seabirds). The stability of prey resources appears to be a key factor in mediating predator interactions with other ocean characteristics. Seabirds reliant on highly-variable zooplankton prey show long-term changes as open water increases, whereas walruses taking benthic prey in biomass hotspots respond to sea-ice changes in the short-term. A better understanding of how variability scales up from prey to predators and how prey resource stability (including how critical prey respond to environmental changes over space and time) might be altered by climate and anthropogenic stressors is essential to

Fine-Scale Cartography of Human Impacts along French Mediterranean Coasts: A Relevant Map for the Management of Marine Ecosystems.

Directory of Open Access Journals (Sweden)

Florian Holon

Full Text Available Ecosystem services provided by oceans and seas support most human needs but are threatened by human activities. Despite existing maps illustrating human impacts on marine ecosystems, information remains either large-scale but rough and insufficient for stakeholders (1 km² grid, lack of data along the coast or fine-scale but fragmentary and heterogeneous in methodology. The objectives of this study are to map and quantify the main pressures exerted on near-coast marine ecosystems, at a large spatial scale though in fine and relevant resolution for managers (one pixel = 20 x 20 m. It focuses on the French Mediterranean coast (1,700 km of coastline including Corsica at a depth of 0 to 80 m. After completing and homogenizing data presently available under GIS on the bathymetry and anthropogenic pressures but also on the seabed nature and ecosystem vulnerability, we provide a fine modeling of the extent and impacts of 10 anthropogenic pressures on marine habitats. The considered pressures are man-made coastline, boat anchoring, aquaculture, urban effluents, industrial effluents, urbanization, agriculture, coastline erosion, coastal population and fishing. A 1:10 000 continuous habitat map is provided considering 11 habitat classes. The marine bottom is mostly covered by three habitats: infralittoral soft bottom, Posidonia oceanica meadows and circalittoral soft bottom. Around two thirds of the bottoms are found within medium and medium high cumulative impact categories. Seagrass meadows are the most impacted habitats. The most important pressures (in area and intensity are urbanization, coastal population, coastal erosion and man-made coastline. We also identified areas in need of a special management interest. This work should contribute to prioritize environmental needs, as well as enhance the development of indicators for the assessment of the ecological status of coastal systems. It could also help better apply and coordinate management measures

Fine-Scale Cartography of Human Impacts along French Mediterranean Coasts: A Relevant Map for the Management of Marine Ecosystems.

Science.gov (United States)

Holon, Florian; Mouquet, Nicolas; Boissery, Pierre; Bouchoucha, Marc; Delaruelle, Gwenaelle; Tribot, Anne-Sophie; Deter, Julie

2015-01-01

Ecosystem services provided by oceans and seas support most human needs but are threatened by human activities. Despite existing maps illustrating human impacts on marine ecosystems, information remains either large-scale but rough and insufficient for stakeholders (1 km² grid, lack of data along the coast) or fine-scale but fragmentary and heterogeneous in methodology. The objectives of this study are to map and quantify the main pressures exerted on near-coast marine ecosystems, at a large spatial scale though in fine and relevant resolution for managers (one pixel = 20 x 20 m). It focuses on the French Mediterranean coast (1,700 km of coastline including Corsica) at a depth of 0 to 80 m. After completing and homogenizing data presently available under GIS on the bathymetry and anthropogenic pressures but also on the seabed nature and ecosystem vulnerability, we provide a fine modeling of the extent and impacts of 10 anthropogenic pressures on marine habitats. The considered pressures are man-made coastline, boat anchoring, aquaculture, urban effluents, industrial effluents, urbanization, agriculture, coastline erosion, coastal population and fishing. A 1:10 000 continuous habitat map is provided considering 11 habitat classes. The marine bottom is mostly covered by three habitats: infralittoral soft bottom, Posidonia oceanica meadows and circalittoral soft bottom. Around two thirds of the bottoms are found within medium and medium high cumulative impact categories. Seagrass meadows are the most impacted habitats. The most important pressures (in area and intensity) are urbanization, coastal population, coastal erosion and man-made coastline. We also identified areas in need of a special management interest. This work should contribute to prioritize environmental needs, as well as enhance the development of indicators for the assessment of the ecological status of coastal systems. It could also help better apply and coordinate management measures at a relevant

Anthropogenic effect on avalanche and debris flow activity

Directory of Open Access Journals (Sweden)

S. A. Sokratov

2013-01-01

Full Text Available The paper presents examples of the change in snow avalanches and debris flows activity due to the anthropogenic pressure on vegetation and relief. The changes in dynamical characteristics of selected snow avalanches and debris flows due to the anthropogenic activity are quantified. The conclusion is made that the anthropogenic effects on the snow avalanches and debris flows activity are more pronounced than the possible effects of the climate change. The necessity is expressed on the unavoidable changes of the natural environment as the result of a construction and of use of the constructed infrastructure to be account for in corresponding planning of the protection measures.

Measurement of undisturbed di-nitrogen emissions from aquatic ecosystems

Science.gov (United States)

Qin, Shuping, Clough, Timothy, Lou, Jiafa; Hu, Chunsheng; Oenema, Oene; Wrage-Mönnig, Nicole; Zhang, Yuming

2016-04-01

Increased production of reactive nitrogen (Nr) from atmospheric di-nitrogen (N2) during the last century has greatly contributed to increased food production1-4. However, enriching the biosphere with Nr through N fertilizer production, combustion, and biological N2 fixation has also caused a series of negative effects on global ecosystems 5,6, especially aquatic ecosystems7. The main pathway converting Nr back into the atmospheric N2 pool is the last step of the denitrification process, i.e., the reduction of nitrous oxide (N2O) into N2 by micro-organisms7,8. Despite several attempts9,10, there is not yet an accurate, fast and direct method for measuring undisturbed N2 fluxes from denitrification in aquatic sediments at the field scale11-14. Such a method is essential to study the feedback of aquatic ecosystems to Nr inputs1,2,7. Here we show that the measurement of both N2O emission and its isotope signature can be used to infer the undisturbed N2 fluxes from aquatic ecosystems. The microbial reduction of N2O increases the natural abundance of 15N-N2O relative to 14N-N2O (δ15N-N2O). We observed linear relationships between δ15N-N2O and the logarithmic transformed N2O/(N2+N2O) emission ratios. Through independent measurements, we verified that the undisturbed N2 flux from aquatic ecosystems can be inferred from measurements of N2O emissions and the δ15N-N2O signature. Our method allows the determination of field-scale N2 fluxes from undisturbed aquatic ecosystems, and thereby allows model predictions of denitrification rates to be tested. The undisturbed N2 fluxes observed are almost one order of magnitude higher than those estimated by the traditional method, where perturbation of the system occurs, indicating that the ability of aquatic ecosystems to remove Nr may have been severely underestimated.

Net ecosystem carbon dioxide exchange in tropical rainforests - sensitivity to environmental drivers and flux measurement methodology

Science.gov (United States)

Fu, Z.; Stoy, P. C.

2017-12-01

Tropical rainforests play a central role in the Earth system services of carbon metabolism, climate regulation, biodiversity maintenance, and more. They are under threat by direct anthropogenic effects including deforestation and indirect anthropogenic effects including climate change. A synthesis of the factors that determine the net ecosystem exchange of carbon dioxide (NEE) across multiple time scales in different tropical rainforests has not been undertaken to date. Here, we study NEE and its components, gross primary productivity (GPP) and ecosystem respiration (RE), across thirteen tropical rainforest research sites with 63 total site-years of eddy covariance data. Results reveal that the five ecosystems that have greater carbon uptakes (with the magnitude of GPP greater than 3000 g C m-2 y-1) sequester less carbon - or even lose it - on an annual basis at the ecosystem scale. This counterintuitive result is because high GPP is compensated by similar magnitudes of RE. Sites that provided subcanopy CO2 storage observations had higher average magnitudes of GPP and RE and consequently lower NEE, highlighting the importance of measurement methodology for understanding carbon dynamics in tropical rainforests. Vapor pressure deficit (VPD) constrained GPP at all sites, but to differing degrees. Many environmental variables are significantly related to NEE at time scales greater than one year, and NEE at a rainforest in Malaysia is significantly related to soil moisture variability at seasonal time scales. Climate projections from 13 general circulation models (CMIP5) under representative concentration pathway (RCP) 8.5 suggest that many current tropical rainforest sites on the cooler end of the current temperature range are likely to reach a climate space similar to present-day warmer sites by the year 2050, and warmer sites will reach a climate space not currently experienced. Results demonstrate the need to quantify if mature tropical trees acclimate to heat and

The impact of extreme flooding events and anthropogenic stressors on the macrobenthic communities’ dynamics

Science.gov (United States)

Cardoso, P. G.; Raffaelli, D.; Lillebø, A. I.; Verdelhos, T.; Pardal, M. A.

2008-02-01

Marine and coastal environments are among the most ecologically and socio-economically important habitats on Earth. However, climate change associated with a variety of anthropogenic stressors (e.g. eutrophication) may interact to produce combined impacts on biodiversity and ecosystem functioning, which in turn will have profound implications for marine ecosystems and the economic and social systems that depend upon them. Over period 1980-2000, the environment of the Mondego estuary, Portugal, has deteriorated through eutrophication, manifested in the replacement of seagrasses by opportunistic macroalgae, degradation of water quality and increased turbidity, and the system has also experienced extreme flood events. A restoration plan was implemented in 1998 which aimed to reverse the eutrophication effects, especially to restore the original natural seagrass ( Zostera noltii) community. This paper explores the interactions between extreme weather events (e.g. intense floods) and anthropogenic stressors (e.g. eutrophication) on the dynamics of the macrobenthic assemblages and the socio-economic implications that follow. We found that during the previous decade, the intensification of extreme flooding events had significant effects on the structure and functioning of macrobenthic communities, specifically a decline in total biomass, a decline in species richness and a decline in suspension feeders. However, the earlier eutrophication process also strongly modified the macrobenthic community, seen as a decline in species richness, increase in detritivores and a decline in herbivores together with a significant increase in small deposit-feeding polychaetes. After the implementation of the management plan, macrobenthic assemblages seemed to be recovering from eutrophication, but it is argued here that those earlier impacts reduced system stability and the resilience of the macrobenthic assemblages, so that its ability to cope with other stressors was compromised. Thus

Mangrove Carbon Stocks and Ecosystem Cover Dynamics in Southwest Madagascar and the Implications for Local Management

Directory of Open Access Journals (Sweden)

Lisa Benson

2017-05-01

Full Text Available Of the numerous ecosystem services mangroves provide, carbon storage is gaining particular attention for its potential role in climate change mitigation strategies. Madagascar contains 2% of the world’s mangroves, over 20% of which is estimated to have been deforested through charcoal production, timber extraction and agricultural development. This study presents a carbon stock assessment of the mangroves in Helodrano Fagnemotse in southwest Madagascar alongside an analysis of mangrove land-cover change from 2002 to 2014. Similar to other mangrove ecosystems in East Africa, higher stature, closed-canopy mangroves in southwest Madagascar were estimated to contain 454.92 (±26.58 Mg·C·ha−1. Although the mangrove extent in this area is relatively small (1500 ha, these mangroves are of critical importance to local communities and anthropogenic pressures on coastal resources in the area are increasing. This was evident in both field observations and remote sensing analysis, which indicated an overall net loss of 3.18% between 2002 and 2014. Further dynamics analysis highlighted widespread transitions of dense, higher stature mangroves to more sparse mangrove areas indicating extensive degradation. Harnessing the value that the carbon stored within these mangroves holds on the voluntary carbon market could generate revenue to support and incentivise locally-led sustainable mangrove management, improve livelihoods and alleviate anthropogenic pressures.

Emerging Diseases in European Forest Ecosystems and Responses in Society

Directory of Open Access Journals (Sweden)

Johanna B. Boberg

2011-04-01

Full Text Available New diseases in forest ecosystems have been reported at an increasing rate over the last century. Some reasons for this include the increased disturbance by humans to forest ecosystems, changed climatic conditions and intensified international trade. Although many of the contributing factors to the changed disease scenarios are anthropogenic, there has been a reluctance to control them by legislation, other forms of government authority or through public involvement. Some of the primary obstacles relate to problems in communicating biological understanding of concepts to the political sphere of society. Relevant response to new disease scenarios is very often associated with a proper understanding of intraspecific variation in the challenging pathogen. Other factors could be technical, based on a lack of understanding of possible countermeasures. There are also philosophical reasons, such as the view that forests are part of the natural ecosystems and should not be managed for natural disturbances such as disease outbreaks. Finally, some of the reasons are economic or political, such as a belief in free trade or reluctance to acknowledge supranational intervention control. Our possibilities to act in response to new disease threats are critically dependent on the timing of efforts. A common recognition of the nature of the problem and adapting vocabulary that describe relevant biological entities would help to facilitate timely and adequate responses in society to emerging diseases in forests.

Evapotranspiration Power Law in Self-Organized and Human-Managed Ecosystems

Science.gov (United States)

Zeng, R.; Cai, X.

2017-12-01

Natural systems display a profound degree of self-organization, often apparent even to the untrained eye. However, in this age of increased coupling among human and natural systems, it is unclear to what degree natural organization principles continue to govern human-managed landscapes. Here we present an emerging characteristic of terrestrial evapotranspiration (ET), one of the key components of the water cycle and energy budget, adhered to by both naturally organized and intensively managed landscapes. We find that ET variance and ET mean for ecosystems throughout the world with diverse climate conditions, vegetation structures, and land covers and land uses organize themselves according to a specific power law curve. From multi-source observations, the ET power law curve stands true through varying spatial scales, from field to region. Moreover, a phenomenon of similar ecosystems gravitating toward particular segments of the power law curve, suggests that the feature of self-optimization of ecosystems establishes the ET power law together with climatic conditions. Perhaps surprisingly, we find that landscapes persistently follow the power law curve even upon human-induced transition from rain-fed to irrigated agriculture in the American High Plains and from wetland to agricultural land in American Midwest. As such, the ET power law can be an informative tool for predicting consequences of anthropogenic disturbances to the hydrologic cycle and understanding constraints to sustainable land use.

Blue whales respond to anthropogenic noise.

Directory of Open Access Journals (Sweden)

Mariana L Melcón

Full Text Available Anthropogenic noise may significantly impact exposed marine mammals. This work studied the vocalization response of endangered blue whales to anthropogenic noise sources in the mid-frequency range using passive acoustic monitoring in the Southern California Bight. Blue whales were less likely to produce calls when mid-frequency active sonar was present. This reduction was more pronounced when the sonar source was closer to the animal, at higher sound levels. The animals were equally likely to stop calling at any time of day, showing no diel pattern in their sensitivity to sonar. Conversely, the likelihood of whales emitting calls increased when ship sounds were nearby. Whales did not show a differential response to ship noise as a function of the time of the day either. These results demonstrate that anthropogenic noise, even at frequencies well above the blue whales' sound production range, has a strong probability of eliciting changes in vocal behavior. The long-term implications of disruption in call production to blue whale foraging and other behaviors are currently not well understood.

Paleolimnological investigations of anthropogenic environmental change in Lake Tanganyika: I. An introduction to the project

Science.gov (United States)

Cohen, A.S.; Palacios-Fest, M. R.; McGill, J.; Swarzenski, P.W.; Verschuren, D.; Sinyinza, R.; Songori, T.; Kakagozo, B.; Syampila, M.; O'Reilly, C. M.; Alin, S.R.

2005-01-01

We investigated paleolimnological records from a series of river deltas around the northeastern rim of Lake Tanganyika, East Africa (Tanzania and Burundi) in order to understand the history of anthropogenic activity in the lake's catchment over the last several centuries, and to determine the impact of these activities on the biodiversity of littoral and sublittoral lake communities. Sediment pollution caused by increased rates of soil erosion in deforested watersheds has caused significant changes in aquatic communities along much of the lake's shoreline. We analyzed the effects of sediment discharge on biodiversity around six deltas or delta complexes on the east coast of Lake Tanganyika: the Lubulungu River delta, Kabesi River delta, Nyasanga/Kahama River deltas, and Mwamgongo River delta in Tanzania; and the Nyamuseni River delta and Karonge/Kirasa River deltas in Burundi. Collectively, these deltas and their associated rivers were chosen to represent a spectrum of drainage-basin sizes and disturbance levels. By comparing deltas that are similar in watershed attributes (other than disturbance levels), our goal was to explore a series of historical "experiments" at the watershed scale, with which we could more clearly evaluate hypotheses of land use or other effects on nearshore ecosystems. Here we discuss these deltas, their geologic and physiographic characteristics, and the field procedures used for coring and sampling the deltas, and various indicators of anthropogenic impact. ?? Springer 2005.

Singular perturbation of simple eigenvalues

International Nuclear Information System (INIS)

Greenlee, W.M.

1976-01-01

Two operator theoretic theorems which generalize those of asymptotic regular perturbation theory and which apply to singular perturbation problems are proved. Application of these theorems to concrete problems is involved, but the perturbation expansions for eigenvalues and eigenvectors are developed in terms of solutions of linear operator equations. The method of correctors, as well as traditional boundary layer techniques, can be used to apply these theorems. The current formulation should be applicable to highly singular ''hard core'' potential perturbations of the radial equation of quantum mechanics. The theorems are applied to a comparatively simple model problem whose analysis is basic to that of the quantum mechanical problem

Base case and perturbation scenarios

Energy Technology Data Exchange (ETDEWEB)

Edmunds, T

1998-10-01

This report describes fourteen energy factors that could affect electricity markets in the future (demand, process, source mix, etc.). These fourteen factors are believed to have the most influence on the State's energy environment. A base case, or most probable, characterization is given for each of these fourteen factors over a twenty year time horizon. The base case characterization is derived from quantitative and qualitative information provided by State of California government agencies, where possible. Federal government databases are nsed where needed to supplement the California data. It is envisioned that a initial selection of issue areas will be based upon an evaluation of them under base case conditions. For most of the fourteen factors, the report identities possible perturbations from base case values or assumptions that may be used to construct additional scenarios. Only those perturbations that are plausible and would have a significant effect on energy markets are included in the table. The fourteen factors and potential perturbations of the factors are listed in Table 1.1. These perturbations can be combined to generate internally consist.ent. combinations of perturbations relative to the base case. For example, a low natural gas price perturbation should be combined with a high natural gas demand perturbation. The factor perturbations are based upon alternative quantitative forecasts provided by other institutions (the Department of Energy - Energy Information Administration in some cases), changes in assumptions that drive the quantitative forecasts, or changes in assumptions about the structure of the California energy markets. The perturbations are intended to be used for a qualitative reexamination of issue areas after an initial evaluation under the base case. The perturbation information would be used as a "tiebreaker;" to make decisions regarding those issue areas that were marginally accepted or rejected under the base case. Hf a

Water and Nitrogen Limitations of Ecosystem Processes Across Three Dryland Plant Communities

Science.gov (United States)

Beltz, C.; Lauenroth, W. K.; Burke, I. C.

2017-12-01

The availability of water and nitrogen (N) play a major role in controlling the distribution of ecosystem types and the rates of ecosystem processes across the globe. Both these resources are being altered by human activity. Anthropogenic fixation of N has increased inputs into the biosphere from 0.5 kg N ha-1 yr-1 to upwards of 10 kg N ha-1 yr-1, while the amount and seasonality of precipitation are expected to continue to change. Within dryland environments, the relationships between increasingly available N and ecosystem processes are especially complex due to dryland's characteristic strong limitation by low and highly variable precipitation. Other experiments have shown that this interplay between N and water can cause temporally complex co-limitation and spatially complex responses with variable effects on ecosystems, such as those to net primary productivity, soil respiration, and plant community composition. Research spanning multiple dryland plant communities is critical for generalizing findings to the 40% of the Earth's terrestrial surface covered in dryland ecosystems. Given IPCC projections in which both N availability and precipitation are altered, examining their interactive effect across multiple plant communities is critical to increasing our understanding of the limitations to ecosystem process in drylands. We are studying a gradient of three plant communities representing a C4 grassland (shortgrass steppe), a C3/C4 grassland (mixed grass prairie), and a shrub-dominated ecosystem with C3 and C4 grasses (sagebrush steppe). We added two levels of N (10 kg N ha-1 and 100 kg N ha-1) and increased summer monthly precipitation by 20%. Sites responded differently to treatments, with the scale of effect varying by treatment. The high-level nitrogen increased soil N availability and soil respiration, while decreasing soil carbon in the labile pool in the upper soil layers. These results will allow for better understanding of increased N in combination with

Estimation of water storage changes in small endorheic lakes in Burabay National Nature Park (Northern Kazakhstan, Central Asia); the effect of climate change and anthropogenic influences

Science.gov (United States)

Yapiyev, Vadim; Sagintayev, Zhanay; Verhoef, Anne; Samarkhanov, Kanat; Jumassultanova, Saltanat

2017-04-01

Both climate change and anthropogenic activities contribute to deterioration of terrestrial water resources and ecosystems worldwide. It has been observed in recent decades that water-limited steppe regions of Central Asia are among ecosystems found to exhibit enhanced responses to climate variability. In fact, the largest share of worldwide net loss of permanent water extent is geographically concentrated in the Central Asia and Middle East regions attributed to both climate variability/change and human activities impacts. We used a digital elevation model, digitized bathymetry maps and high resolution Landsat images to estimate the areal water cover extent and volumetric storage changes in small terminal lakes in Burabay National Nature Park (BNNP), located in Northern Central Asia, for the period 2000-2016. Based on the analysis of long-term climatic data from meteorological stations, hydrometeorological network observations as well as regional climate model projections we evaluate the impacts of past thirty years and future climatic conditions on the water balance of BNNP lake catchments. The anthropogenic water consumption was estimated based on data collected at a local water supply company and regulation authorities. One the one hand historical in-situ observations and future climate projections do not show a significant change in precipitation in BNNP. On the other hand both observations and the model demonstrate steadily rising air temperatures in the area. It is concluded that the long-term decline in water levels for most of these lakes can be largely attributed to climate change (but only via changes in air temperature, causing evaporation to exceed precipitation) and not to direct anthropogenic influences such as increased water withdrawals. In addition, the two largest lakes, showing the highest historical water level decline, do not have sufficient water drainage basin area to sustain water levels under increased evaporation rates.

Scalar cosmological perturbations

International Nuclear Information System (INIS)

Uggla, Claes; Wainwright, John

2012-01-01

Scalar perturbations of Friedmann-Lemaitre cosmologies can be analyzed in a variety of ways using Einstein's field equations, the Ricci and Bianchi identities, or the conservation equations for the stress-energy tensor, and possibly introducing a timelike reference congruence. The common ground is the use of gauge invariants derived from the metric tensor, the stress-energy tensor, or from vectors associated with a reference congruence, as basic variables. Although there is a complication in that there is no unique choice of gauge invariants, we will show that this can be used to advantage. With this in mind our first goal is to present an efficient way of constructing dimensionless gauge invariants associated with the tensors that are involved, and of determining their inter-relationships. Our second goal is to give a unified treatment of the various ways of writing the governing equations in dimensionless form using gauge-invariant variables, showing how simplicity can be achieved by a suitable choice of variables and normalization factors. Our third goal is to elucidate the connection between the metric-based approach and the so-called 1 + 3 gauge-invariant approach to cosmological perturbations. We restrict our considerations to linear perturbations, but our intent is to set the stage for the extension to second-order perturbations. (paper)

Divergent Perturbation Series

International Nuclear Information System (INIS)

Suslov, I.M.

2005-01-01

Various perturbation series are factorially divergent. The behavior of their high-order terms can be determined by Lipatov's method, which involves the use of instanton configurations of appropriate functional integrals. When the Lipatov asymptotic form is known and several lowest order terms of the perturbation series are found by direct calculation of diagrams, one can gain insight into the behavior of the remaining terms of the series, which can be resummed to solve various strong-coupling problems in a certain approximation. This approach is demonstrated by determining the Gell-Mann-Low functions in φ 4 theory, QED, and QCD with arbitrary coupling constants. An overview of the mathematical theory of divergent series is presented, and interpretation of perturbation series is discussed. Explicit derivations of the Lipatov asymptotic form are presented for some basic problems in theoretical physics. A solution is proposed to the problem of renormalon contributions, which hampered progress in this field in the late 1970s. Practical perturbation-series summation schemes are described both for a coupling constant of order unity and in the strong-coupling limit. An interpretation of the Borel integral is given for 'non-Borel-summable' series. Higher order corrections to the Lipatov asymptotic form are discussed

Investigating Anthropogenic Perturbations on Carbon Cycling in AN Urbanized Tropical West African Estuary

Science.gov (United States)

Atekwana, E. A.; Ali, H.; Ndondo, N.

2017-12-01

We conducted an axial survey of salinity, stable isotopes of oxygen (δ18O) of water, nitrates, pH, alkalinity, dissolved inorganic carbon (DIC) and stable isotopes of carbon (δ13C) of DIC in the Douala Estuary, Cameroon, West Africa. Our objective was to assess anthropogenic impact of pollution on carbon cycling in this urbanized tropical estuary. Salinity ranged from 0.03 to 23.95 and increased steeply from the head to 15 km, stayed nearly constant to 24 km, and then increased steadily to the mouth. The δ18O ranged from -0.4‰ to -5.0‰ and increased steadily from the head to13 km, then slowly to 24 km before increasing sharply to the mouth. The similar behaviour between salinity and δ18O was caused by dilution from the Mungo R. to the west and the Dibamba R. to the east. The nitrate concentrations ranged from 0 to 34 mg/L and behaved similarly to salinity, which was low at the head (0 - 4 km), increased steeply to 15 km and stayed nearly constant to 24 km before increasing sharply to mouth. The spatial distribution of nitrates indicate pollution from agricultural input through the Mungo R., sewage discharge along the urbanized Wouri R. and Dibamba R. and from industries and the port facility along the estuary. The alkalinity concentrations ranged from 12 to 60 mg/Kg and DIC concentrations ranged from 2.9 to 15.5 mg C/Kg, are both positively correlated (R2 = 0.94) and both increased from the estuary head towards the mouth. The salinity concentrations show a good positive correlation (R2 = 0.98) with DIC concentrations. The partial pressure of CO2 (pCO2) which was decreasing from the estuary head towards the mouth reverses at 10 km and increases down estuary towards the mouth. The pCO2 behaviour indicates that the axial increase in the DIC concentrations is from the addition of CO2, although mixing of ocean water with higher DIC concentrations can also explain this observation. The generation of CO2 in the water column is reflected in the pH which increased

ANTHROPOGENIC ACTIVITIES THREATENING THE ...

African Journals Online (AJOL)

Osondu

2012-02-17

Feb 17, 2012 ... anthropogenic activities across the protected areas in the country. ... education and provision of fund to support sustainable livelihood practices. ... wildlife conservation and tourism. ... Fig: 1 Map of Oyo State showing location of Old Oyo National Park and adjoining community. #. #. # .... This was the view of.

Genetic Diversity of the Black Mangrove Avicennia germinans (L. Stearn in Northwestern Mexico

Directory of Open Access Journals (Sweden)

Olivia Millán-Aguilar

2016-09-01

Full Text Available Mangrove forests of Mexico have been threatened by the effects of anthropogenic activities during the last decades, mostly related to aquaculture, agriculture, livestock and urban development. Genetic diversity and fine-scale genetic structure of two generations of the black mangrove Avicennia germinans (L. Stearn were investigated in perturbed and preserved sites from three lagoon systems in Sinaloa, Mexico. Genetic diversity and overall genetic structure were similar between perturbed and preserved sites. However, lower levels of fine-scale spatial genetic structure were observed in two of the younger (sapling generations. We attribute this to differences in local dynamics of each lagoon system, their status of conservation and levels of fragmentation. Also, low connectivity and the effects of disturbance could restrict the movement of pollinators and seed dispersal capabilities, resulting in low levels of genetic diversity and signs of inbreeding. Perturbed populations of A. germinans may play an important role in in situ conservation of this complex ecosystem.

Invasive ecosystem engineer selects for different phenotypes of an associated native species.

Science.gov (United States)

Wright, Jeffrey T; Gribben, Paul E; Byers, James E; Monro, Keyne

2012-06-01

Invasive habitat-forming ecosystem engineers modify the abiotic environment and thus represent a major perturbation to many ecosystems. Because native species often persist in these invaded habitats but have no shared history with the ecosystem engineer, the engineer may impose novel selective pressure on native species. In this study, we used a phenotypic selection framework to determine whether an invasive habitat-forming ecosystem engineer (the seaweed Caulerpa taxifolia) selects for different phenotypes of a common co-occurring native species (the bivalve Anadara trapezia). Compared to unvegetated habitat, Caulerpa habitat has lower water flow, lower dissolved oxygen, and sediments are more silty and anoxic. We determined the performance consequences of variation in key functional traits that may be affected by these abiotic changes (shell morphology, gill mass, and palp mass) for Anadara transplanted into Caulerpa and unvegetated habitat. Both linear and nonlinear performance gradients in Anadara differed between habitats, and these gradients were stronger in Caulerpa compared to unvegetated sediment. Moreover, in Caulerpa alternate phenotypes performed well, and these phenotypes were different from the dominant phenotype in unvegetated sediment. By demonstrating that phenotype-performance gradients differ between habitats, we have highlighted a role for Caulerpa as an agent of selection on native species.

Large-order perturbation theory

International Nuclear Information System (INIS)

Wu, T.T.

1982-01-01

The original motivation for studying the asymptotic behavior of the coefficients of perturbation series came from quantum field theory. An overview is given of some of the attempts to understand quantum field theory beyond finite-order perturbation series. At least is the case of the Thirring model and probably in general, the full content of a relativistic quantum field theory cannot be recovered from its perturbation series. This difficulty, however, does not occur in quantum mechanics, and the anharmonic oscillator is used to illustrate the methods used in large-order perturbation theory. Two completely different methods are discussed, the first one using the WKB approximation, and a second one involving the statistical analysis of Feynman diagrams. The first one is well developed and gives detailed information about the desired asymptotic behavior, while the second one is still in its infancy and gives instead information about the distribution of vertices of the Feynman diagrams

Assessment of global industrial-age anthropogenic arsenic contamination.

Science.gov (United States)

Han, Fengxiang X; Su, Yi; Monts, David L; Plodinec, M John; Banin, Amos; Triplett, Glover E

2003-09-01

Arsenic, a carcinogenic trace element, threatens not only the health of millions of humans and other living organisms, but also global sustainability. We present here, for the first time, the global industrial-age cumulative anthropogenic arsenic production and its potential accumulation and risks in the environment. In 2000, the world cumulative industrial-age anthropogenic arsenic production was 4.53 million tonnes. The world-wide coal and petroleum industries accounted for 46% of global annual gross arsenic production, and their overall contribution to industrial-age gross arsenic production was 27% in 2000. Global industrial-age anthropogenic As sources (as As cumulative production) follow the order: As mining production>As generated from coal>As generated from petroleum. The potential industrial-age anthropogenic arsenic input in world arable surface in 2000 was 2.18 mg arsenic kg(-1), which is 1.2 times that in the lithosphere. The development of substitute materials for arsenic applications in the agricultural and forestry industries and controls of arsenic emissions from the coal industry may be possible strategies to significantly decrease arsenic pollution sources and dissipation rates into the environment.

Perturbation theory in light-cone gauge

International Nuclear Information System (INIS)

Vianello, Eliana

2000-01-01

Perturbation calculations are presented for the light-cone gauge Schwinger model. Eigenstates can be calculated perturbatively but the perturbation theory is nonstandard. We hope to extend the work to QCD 2 to resolve some outstanding issues in those theories

On dark energy isocurvature perturbation

International Nuclear Information System (INIS)

Liu, Jie; Zhang, Xinmin; Li, Mingzhe

2011-01-01

Determining the equation of state of dark energy with astronomical observations is crucially important to understand the nature of dark energy. In performing a likelihood analysis of the data, especially of the cosmic microwave background and large scale structure data the dark energy perturbations have to be taken into account both for theoretical consistency and for numerical accuracy. Usually, one assumes in the global fitting analysis that the dark energy perturbations are adiabatic. In this paper, we study the dark energy isocurvature perturbation analytically and discuss its implications for the cosmic microwave background radiation and large scale structure. Furthermore, with the current astronomical observational data and by employing Markov Chain Monte Carlo method, we perform a global analysis of cosmological parameters assuming general initial conditions for the dark energy perturbations. The results show that the dark energy isocurvature perturbations are very weakly constrained and that purely adiabatic initial conditions are consistent with the data

Understanding Complex Human Ecosystems: The Case of Ecotourism on Bonaire

Directory of Open Access Journals (Sweden)

Thomas Abel

2003-12-01

Full Text Available It is suggested that ecotourism development on the island of Bonaire can be productively understood as a perturbation of a complex human ecosystem. Inputs associated with ecotourism have fueled transformations of the island ecology and sociocultural system. The results of this study indicate that Bonaire's social and economic hierarchy is approaching a new, stable systems state following a 50-yr transition begun by government and industry that stabilized with the appearance of ecotourism development and population growth. Ecotourism can be understood to have "filled in" the middle of the production hierarchy of Bonaire. Interpreted from this perspective, population growth has completed the transformation by expanding into production niches at smaller scales in the production hierarchy. Both a consequence and a cause, ecotourism has transformed the island's social structure and demography. The theory and methods applied in this case study of interdisciplinary research in the field of human ecosystems are also presented.

Perturbation Theory of Embedded Eigenvalues

DEFF Research Database (Denmark)

Engelmann, Matthias

project gives a general and systematic approach to analytic perturbation theory of embedded eigenvalues. The spectral deformation technique originally developed in the theory of dilation analytic potentials in the context of Schrödinger operators is systematized by the use of Mourre theory. The group...... of dilations is thereby replaced by the unitary group generated y the conjugate operator. This then allows to treat the perturbation problem with the usual Kato theory.......We study problems connected to perturbation theory of embedded eigenvalues in two different setups. The first part deals with second order perturbation theory of mass shells in massive translation invariant Nelson type models. To this end an expansion of the eigenvalues w.r.t. fiber parameter up...

A deep transcriptomic resource for the copepod crustacean Labidocera madurae: A potential indicator species for assessing near shore ecosystem health.

Directory of Open Access Journals (Sweden)

Vittoria Roncalli

Full Text Available Coral reef ecosystems of many sub-tropical and tropical marine coastal environments have suffered significant degradation from anthropogenic sources. Research to inform management strategies that mitigate stressors and promote a healthy ecosystem has focused on the ecology and physiology of coral reefs and associated organisms. Few studies focus on the surrounding pelagic communities, which are equally important to ecosystem function. Zooplankton, often dominated by small crustaceans such as copepods, is an important food source for invertebrates and fishes, especially larval fishes. The reef-associated zooplankton includes a sub-neustonic copepod family that could serve as an indicator species for the community. Here, we describe the generation of a de novo transcriptome for one such copepod, Labidocera madurae, a pontellid from an intensively-studied coral reef ecosystem, Kāne'ohe Bay, Oahu, Hawai'i. The transcriptome was assembled using high-throughput sequence data obtained from whole organisms. It comprised 211,002 unique transcripts, including 72,391 with coding regions. It was assessed for quality and completeness using multiple workflows. Bench-marking-universal-single-copy-orthologs (BUSCO analysis identified transcripts for 88% of expected eukaryotic core proteins. Targeted gene-discovery analyses included searches for transcripts coding full-length "giant" proteins (>4,000 amino acids, proteins and splice variants of voltage-gated sodium channels, and proteins involved in the circadian signaling pathway. Four different reference transcriptomes were generated and compared for the detection of differential gene expression between copepodites and adult females; 6,229 genes were consistently identified as differentially expressed between the two regardless of reference. Automated bioinformatics analyses and targeted manual gene curation suggest that the de novo assembled L. madurae transcriptome is of high quality and completeness. This

A deep transcriptomic resource for the copepod crustacean Labidocera madurae: A potential indicator species for assessing near shore ecosystem health

Science.gov (United States)

Christie, Andrew E.; Sommer, Stephanie A.; Cieslak, Matthew C.; Hartline, Daniel K.; Lenz, Petra H.

2017-01-01

Coral reef ecosystems of many sub-tropical and tropical marine coastal environments have suffered significant degradation from anthropogenic sources. Research to inform management strategies that mitigate stressors and promote a healthy ecosystem has focused on the ecology and physiology of coral reefs and associated organisms. Few studies focus on the surrounding pelagic communities, which are equally important to ecosystem function. Zooplankton, often dominated by small crustaceans such as copepods, is an important food source for invertebrates and fishes, especially larval fishes. The reef-associated zooplankton includes a sub-neustonic copepod family that could serve as an indicator species for the community. Here, we describe the generation of a de novo transcriptome for one such copepod, Labidocera madurae, a pontellid from an intensively-studied coral reef ecosystem, Kāne‘ohe Bay, Oahu, Hawai‘i. The transcriptome was assembled using high-throughput sequence data obtained from whole organisms. It comprised 211,002 unique transcripts, including 72,391 with coding regions. It was assessed for quality and completeness using multiple workflows. Bench-marking-universal-single-copy-orthologs (BUSCO) analysis identified transcripts for 88% of expected eukaryotic core proteins. Targeted gene-discovery analyses included searches for transcripts coding full-length “giant” proteins (>4,000 amino acids), proteins and splice variants of voltage-gated sodium channels, and proteins involved in the circadian signaling pathway. Four different reference transcriptomes were generated and compared for the detection of differential gene expression between copepodites and adult females; 6,229 genes were consistently identified as differentially expressed between the two regardless of reference. Automated bioinformatics analyses and targeted manual gene curation suggest that the de novo assembled L. madurae transcriptome is of high quality and completeness. This

The direct exploitation in the mangrove ecosystem in Central Java and the land use in its surrounding; degradation and its restoration effort