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Sample records for adjacent aquatic ecosystems

  1. AQUATIC ECOSYSTEMS,

    EPA Science Inventory

    Aquatic ecosystems are a vital part of the urban water cycle (and of urban areas more broadly), and, if healthy, provide a range of goods and services valued by humans (Meyer 1997). For example, aquatic ecosystems (e.g., rivers, lakes, wetlands) provide potable water, food resou...

  2. Non-native earthworms in riparian soils increase nitrogen flux into adjacent aquatic ecosystems.

    PubMed

    Costello, David M; Lamberti, Gary A

    2008-12-01

    -buffering capacity of riparian zones and altering stoichiometric relationships in adjacent aquatic ecosystems. PMID:18825416

  3. Initial Impacts of the Mount Polley Tailings Pond Breach on Adjacent Aquatic Ecosystems

    NASA Astrophysics Data System (ADS)

    Petticrew, Ellen; Gantner, Nikolaus; Albers, Sam; Owens, Philip

    2015-04-01

    On August 4th 2014, the Mount Polley Tailings pond breach near Likely, B.C., released approximately 24 million cubic metres of tailings material into Polley Lake, Hazeltine Creek and Quesnel Lake. The discharge scoured and eroded a swath of soil and sediment delivering an unknown amount of metals and sediment into this tributary ecosystem of the Fraser River. Subsequent efforts by the mine operator to remediate by pumping tailings water from Polley Lake into Hazeltine Creek, which flows into Quesnel Lake, resulted in additional and continuous release of unknown volumes of contaminated water and sediments into the watershed. Heavy metals (e.g., selenium, copper, or mercury) reported as stored in the tailings pond entered the downstream aquatic environment and have been monitored in the water column of Quesnel Lake since August. These contaminants are likely particle-bound and thus subject to transport over long distances without appreciable degradation, resulting in the potential for chronic exposures and associated toxicological effects in exposed biota. While significant dilution is expected during aquatic transport, and the resulting concentrations in the water will likely be low, concentrations in exposed biota may become of concern over time. Metals such as mercury and selenium undergo bioaccumulation and biomagnification, once incorporated into the food chain/web. Thus, even small concentrations of such contaminants in water can lead to greater concentrations (~100 fold) in top predators. Over time, our predictions are that food web transfer will lead to an increase in concentrations from water (1-2 years)->invertebrates (1-2 yrs) ->fishes (2-5 yrs). Pacific salmon travel great distances in this watershed and may be exposed to contaminated water during their migrations. Resident species will be exposed to the contaminated waters and sediments in the study lakes year round. Little or no background/baseline data for metals in biota from Quesnel Lake exists

  4. BIOGEOCHEMICAL INDICATORS IN AQUATIC ECOSYSTEMS

    EPA Science Inventory

    Loadings of excess organic wastes and associated nutrients to aquatic systems has numerous deleterious consequences with respect to the ecosystem services provided by these important ecosystems including perturbation of organic matter and nutrient cycling rates, reduction in diss...

  5. Systems and Cycles: Learning about Aquatic Ecosystems

    ERIC Educational Resources Information Center

    Hmelo-Silver, Cindy E.; Jordan, Rebecca; Eberbach, Catherine; Rugaber, Spencer; Goel, Ashok

    2011-01-01

    In this research, the authors present both the design and preliminary testing of a technology-intensive classroom intervention designed to support middle schools students' understanding of an aquatic ecosystem. The goals of their intervention are to help learners develop deep understanding of ecosystems and to use tools that make the relationships…

  6. Delineating resource sheds in aquatic ecosystems (presentation)

    EPA Science Inventory

    Analysis of spatially-explicit ecological phenomena in aquatic ecosystems is impeded by a lack of knowledge of, and tools to delimit, spatial patterns of material supply to point locations. Here we apply the concept of "resource sheds" to coasts and watersheds. Resource sheds ar...

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

    NASA Astrophysics Data System (ADS)

    Tockner, K.

    2009-04-01

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

  8. Effective Best Management Practices for Nitrogen Removal in Aquatic Ecosystems

    EPA Science Inventory

    Elevated nitrate levels in streams and groundwater are detrimental to human and ecosystem health. The Ground Water and Ecosystems Restoration Division (GWERD) of the USEPA investigates best management practices (BMP’s) that enhance nitrogen removal in aquatic ecosystems througho...

  9. Energy flow in an arctic aquatic ecosystem

    SciTech Connect

    Schell, D.M.

    1988-12-31

    Natural isotope abundances to trace major pathways of energy flow to consumers in Imnavait Creek and the tundra ecosystem of the R4D watershed with comparative work in the coastal tundra. Our overall goals are to a determine if carbon is accumulating in upland and coastal tundra; determine the role of eroded peat carbon in the aquatic ecosystem; and to determine the distribution of carbon and nitrogen isotopes in the tundra-pond ecosystem to establish the feasibility of using natural differences as tracers. Past work on fishes, birds, and the prey species of insects and aquatic crustaceans has shown that peat carbon is very important in the energy supply supporting the food webs over the course of the year. Obligate freshwater fishes from the coastal lakes and Colville River have been shown to contain up to 60 percent peat carbon at the end of the winter season. In contrast, migratory shorebirds and passerines contained much smaller radiocarbon abundances in summer, indicating a major shift to recent in situ primary production in pond and stream ecosystems in summer months. For the past two years, we have narrowed our focus to the processes supplying carbon to the beaded stream system at MS-117 and have concentrated on determining the transfer and accumulation rates of carbon in the watershed.

  10. Assessment of potential aquatic herbicide impacts to California aquatic ecosystems.

    PubMed

    Siemering, Geoffrey S; Hayworth, Jennifer D; Greenfield, Ben K

    2008-10-01

    A series of legal decisions culminated in 2002 with the California State Water Resources Control Board funding the San Francisco Estuary Institute to develop and implement a 3-year monitoring program to determine the potential environmental impacts of aquatic herbicide applications. The monitoring program was intended to investigate the behavior of all aquatic pesticides in use in California, to determine potential impacts in a wide range of water-body types receiving applications, and to help regulators determine where to direct future resources. A tiered monitoring approach was developed to achieve a balance between program goals and what was practically achievable within the project time and budget constraints. Water, sediment, and biota were collected under "worst-case" scenarios in close association with herbicide applications. Applications of acrolein, copper sulfate, chelated copper, diquat dibromide, glyphosate, fluridone, triclopyr, and 2,4-D were monitored. A range of chemical analyses, toxicity tests, and bioassessments were conducted. At each site, risk quotients were calculated to determine potential impacts. For sediment-partitioning herbicides, sediment quality triad analysis was performed. Worst-case scenario monitoring and special studies showed limited short-term and no long-term toxicity directly attributable to aquatic herbicide applications. Risk quotient calculations called for additional risk characterizations; these included limited assessments for glyphosate and fluridone and more extensive risk assessments for diquat dibromide, chelated copper products, and copper sulfate. Use of surfactants in conjunction with aquatic herbicides was positively associated with greater ecosystem impacts. Results therefore warrant full risk characterization for all adjuvant compounds. PMID:18293029

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

    ERIC Educational Resources Information Center

    Cowan, Christina E.

    This module is part of a series designed to be used by life science students for instruction in the application of physical theory to ecosystem operation. Most modules contain computer programs which are built around a particular application of a physical process. This module explores some of the characteristics of aquatic organisms which can be…

  12. [Virus and prophages in aquatic ecosystems].

    PubMed

    Sime-Ngando, Télesphore; Colombet, Jonathan

    2009-02-01

    In this review, available data on the structure (diversity, abundance, biomass) and functional imprints (bacteriolysis, lysogeny, gene transfers, regulation of prokaryotic diversity) of natural viruses in the context of food webs in aquatic microbial ecology, and the related biogeochemical cycles, are summarized. Viruses are the most abundant, and probably the most diverse, biological entities in aquatic ecosystems and in the biosphere (i.e., viriosphere). Aquatic viruses typically exceed 107 particles/mL in mesotrophic conditions, the majority being represented by phages without tails and by tailed-phages such as members of the family Siphoviridae. Both types of phages have a small capsid and a small genome size, which is considered an evolutionary adaptation to planktonic life. Their contribution to microbial mortality is significant. There is strong evidence that phages exert a significant pressure on the community structure and diversity and on the diversification of potential hosts, mainly through two major pathways: biogeochemical catalysis from lysis products and horizontal gene transfers. In turn, phages are sensitive to environmental factors, both in terms of integrity and of infectivity. Some phages contain typical viral genes that code for biological functions of interest, such as photosynthesis. In general, development in viral ecology is a source of new knowledge for the scientific community in the domain of environmental sciences, but also in the context of evolutionary biology of living cellular organisms, the obligatory hosts for viruses. For example, the recent discovery of a giant virus that becomes ill through infection by another virus (i.e., a viriophage) is fuelling debate about whether viruses are alive. Finally, future research directions are identified in the context of general aquatic ecology, including ecological researches on cyanophages and other phytoplanktonic phages as a priority, primarily in freshwater lakes. PMID:19295641

  13. [Radioecological problems of aquatic ecosystems of the Chernobyl exclusion zone].

    PubMed

    Gudkov, D I; Kuz'menko, M I; Kireev, S I; Nazarov, A B; Shevtsova, N L; Dziubenko, E V; Kaglian, A E

    2009-01-01

    The results of radioactive contamination dynamics in the main components of aquatic ecosystems and the absorbed dose rate for hydrobionts within the Chernobyl accident exclusion zone was analysed. Some cytogenetical and haematological effects of long-term irradiation on aquatic organisms as well as damage of higher aquatic plants by parasitic fungi and gall-producing arthropods were considered. PMID:19507688

  14. The Role of Aquatic Ecosystems in the Elimination of Pollutants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Contamination of aquatic ecosystems is always of concern to environmental scientists; however, these systems also possess unique capabilities allowing them to eliminate or mitigate certain levels of pollutants. Primarily through the presence of vegetation, aquatic ecosystems are known to be capable...

  15. Development of resource shed delineation in aquatic ecosystems

    EPA Science Inventory

    Environmental issues in aquatic ecosystems of high management priority involve spatially explicit phenomena that occur over vast areas. A "landscape" perspective is thus necessary, including an understanding of how ecological phenomena at a local scale are affected by physical fo...

  16. Risk Assessment Considerations for Veterinary Medicines in Aquatic Ecosystems

    EPA Science Inventory

    This chapter provides a critical evaluation of prospective and retrospective risk assessment approaches for veterinary medicines in aquatic ecosystems and provides recommendations for possible alternative approaches for hazard characterization.

  17. Review on environmental alterations propagating from aquatic to terrestrial ecosystems.

    PubMed

    Schulz, Ralf; Bundschuh, Mirco; Gergs, René; Brühl, Carsten A; Diehl, Dörte; Entling, Martin H; Fahse, Lorenz; Frör, Oliver; Jungkunst, Hermann F; Lorke, Andreas; Schäfer, Ralf B; Schaumann, Gabriele E; Schwenk, Klaus

    2015-12-15

    Terrestrial inputs into freshwater ecosystems are a classical field of environmental science. Resource fluxes (subsidy) from aquatic to terrestrial systems have been less studied, although they are of high ecological relevance particularly for the receiving ecosystem. These fluxes may, however, be impacted by anthropogenically driven alterations modifying structure and functioning of aquatic ecosystems. In this context, we reviewed the peer-reviewed literature for studies addressing the subsidy of terrestrial by aquatic ecosystems with special emphasis on the role that anthropogenic alterations play in this water-land coupling. Our analysis revealed a continuously increasing interest in the coupling of aquatic to terrestrial ecosystems between 1990 and 2014 (total: 661 studies), while the research domains focusing on abiotic (502 studies) and biotic (159 studies) processes are strongly separated. Approximately 35% (abiotic) and 25% (biotic) of the studies focused on the propagation of anthropogenic alterations from the aquatic to the terrestrial system. Among these studies, hydromorphological and hydrological alterations were predominantly assessed, whereas water pollution and invasive species were less frequently investigated. Less than 5% of these studies considered indirect effects in the terrestrial system e.g. via food web responses, as a result of anthropogenic alterations in aquatic ecosystems. Nonetheless, these very few publications indicate far-reaching consequences in the receiving terrestrial ecosystem. For example, bottom-up mediated responses via soil quality can cascade over plant communities up to the level of herbivorous arthropods, while top-down mediated responses via predatory spiders can cascade down to herbivorous arthropods and even plants. Overall, the current state of knowledge calls for an integrated assessment on how these interactions within terrestrial ecosystems are affected by propagation of aquatic ecosystem alterations. To fill

  18. DNA barcodes for assessment of the biological integrity of aquatic ecosystems

    EPA Science Inventory

    Water quality regulations and aquatic ecosystem monitoring increasingly rely on direct assessments of biological integrity. Because these aquatic “bioassessments” evaluate the incidence and abundance of sensitive aquatic species, they are able to measure cumulative ecosystem eff...

  19. Endocrine-Disrupting Compounds in Aquatic Ecosystems.

    EPA Science Inventory

    Endocrine disrupting chemicals (EDCs) are a ubiquitous issue of concern in our aquatic systems. Commonly detected EDCs include natural and synthetic hormones, surfactants, plasticizers, disinfectants, herbicides and metals. The potency of these chemicals varies substantially, as ...

  20. Watershed geomorphology modifies the temperature sensitivity of aquatic ecosystem metabolism

    NASA Astrophysics Data System (ADS)

    Jankowski, K. J.; Schindler, D.

    2015-12-01

    How carbon cycles are regulated by temperature remains a substantial uncertainty in our understanding of how watersheds will respond to ongoing climate change. Aquatic ecosystems are significant components of carbon flux to the atmosphere and ocean, yet we have limited understanding of how changing thermal regimes will alter rates of ecosystem metabolic processes, and, therefore, aquatic contributions to carbon cycles at watershed to global scales. Watershed geomorphology controls the landscape-scale distribution of organic material that can form the metabolic base of aquatic ecosystems, which will likely affect the temperature sensitivity of aquatic ecosystem metabolism. Across 23 streams in a boreal river basin, we estimated how temperature sensitivity of ecosystem respiration (ER), an important component of the aquatic C cycle, varied among streams with different watershed characteristics. We found that geomorphic conditions imposed strong ultimate controls on temperature sensitivity: ER in streams draining flat watersheds was much more sensitive to temperature than streams draining steeper watersheds. Further, we show that the link between watershed geomorphology and temperature sensitivity was related to changes in the quality of carbon substrates across the gradient in watershed slope. These results suggest that geomorphic conditions will ultimately control how carbon processing responds to warming climate, thereby affecting carbon transport and storage, and likely food web responses, in river networks.

  1. Nutrient sources and transport along urban flowpaths to aquatic ecosystems

    NASA Astrophysics Data System (ADS)

    Finlay, J. C.; Janke, B.; Baker, L. A.; Hobbie, S. E.; Nidzgorski, D.; Sterner, R.; Wilson, B. N.

    2012-12-01

    Water quality of urban freshwater ecosystems is widely impaired by eutrophication, with little recent improvement and much potential for further degradation due to urban expansion and intensification. Despite the degradation of water quality in urban streams and lakes and adjacent coastal areas, relatively little is known about the relative importance of specific nutrient sources and the processes that regulate their movement across highly modified land-water interfaces. To better understand the nutrient sources and cycling that affect aquatic ecosystems, we assess nutrient movement through urban drainage networks in St. Paul, Minnesota. Nutrient concentrations and flux in stormwater at six intensively monitored sites show consistent seasonal patterns, with peaks in total nitrogen (N) and phosphorus (P) in the late spring. Trees contributed to nutrient movement via litterfall and throughfall to impervious surfaces, with peaks in inputs that corresponded to stormwater nutrient patterns. Despite runoff generated primarily from impervious surfaces, organic carbon and nitrogen concentrations were high, with organic N accounting for >80% of stormwater N loading. Together, these data suggested an important role for urban tree canopies in nutrient mobilization in stormwater. Base flow, present in larger storm drains and buried streams, results primarily from groundwater seepage and from outflow of surface water connected to drains. Base flow contributed significantly to nutrient export, particularly for N (33 to 68% of warm season export) but also for P (8 to 34%). Sites with upstream hydrologic connections to lakes and remnant above-ground stream reaches had higher baseflow organic carbon and P, and reduced N concentrations compared to sites dominated by groundwater. Together, these data show that the characteristics of urban vegetation and the nature of human alterations to hydrologic connections are dominant features influencing the form and amount of nutrient movement

  2. Environmental estrogens in an urban aquatic ecosystem: II. Biological effects.

    PubMed

    Schultz, Melissa M; Minarik, Thomas A; Martinovic-Weigelt, Dalma; Curran, Erin M; Bartell, Stephen E; Schoenfuss, Heiko L

    2013-11-01

    Urban aquatic ecosystems are often overlooked in toxicological studies even though they serve many ecosystem functions and sustain fish populations despite large-scale habitat alterations. However, urban fish populations are likely exposed to a broad range of stressors, including environmental estrogens (EEs) that may affect anatomy, physiology and reproduction of exposed fish. Although significant progress has been made in establishing ecological consequences of EE exposure, these studies have focused largely on hydrologically simple systems that lack the complexity of urban aquatic environments. Therefore, the objective of this study was to assess the occurrence and biological effects of EEs across a large urbanized aquatic ecosystem. A multi-pronged study design was employed relying on quantitative determination of select EEs by liquid chromatography tandem mass spectrometry and repeated biological monitoring of wild-caught and caged fish for indications of endocrine disruption. Over three years, EEs were measured in aqueous samples (n=42 samples) and biological effects assessed in >1200 male fish across the 2000km(2) aquatic ecosystems of the Greater Metropolitan Area of Chicago, IL. Our study demonstrated that in addition to water reclamation plant (WRP) effluents, non-WRP sources contribute significant EE loads to the aquatic ecosystem. While resident and caged male fish responded with the induction of the egg-yolk protein vitellogenin, an indicator of EE exposure, neither resident nor caged sunfish exhibited prevalent histopathological changes to their reproductive organs (i.e., intersex) that have been reported in other studies. Vitellogenin induction was greater in spring than the fall and was not correlated with body condition factor, gonadosomatic index or hepatosomatic index. Exposure effects were not correlated with sites downstream of treated effluent discharge further affirming the complexity of sources and effects of EEs in urban aquatic ecosystems

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

    USGS Publications Warehouse

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

    2012-01-01

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

  4. Energy flow in an arctic aquatic ecosystem

    SciTech Connect

    Schell, D.M.

    1983-12-31

    This component of the terrestrial-aquatic interaction group seeks to use the natural stable carbon isotope ratios and radiocarbon abundances to trace the movement of photosynthate from the terrestrial environment to the stream system at MS-117. In addition to estimating the total flux, we will also attempt to describe the relative fractions derived from modern primary production and that derived from delayed inputs of eroded peat. We will also seek to determine the coupling efficiency of these energy sources to the invertebrate faunal populations in the tundra soils and streams.

  5. Energy flow in an arctic aquatic ecosystem

    SciTech Connect

    Schell, D.M.

    1983-01-01

    This component of the terrestrial-aquatic interaction group seeks to use the natural stable carbon isotope ratios and radiocarbon abundances to trace the movement of photosynthate from the terrestrial environment to the stream system at MS-117. In addition to estimating the total flux, we will also attempt to describe the relative fractions derived from modern primary production and that derived from delayed inputs of eroded peat. We will also seek to determine the coupling efficiency of these energy sources to the invertebrate faunal populations in the tundra soils and streams.

  6. BIOGEOCHEMISTRY OF CHLORINATED ORGANIC CONTAMINANTS IN AQUATIC ECOSYSTEMS

    EPA Science Inventory

    Over the last several years we have conducted both laboratory and field studies to develop a better understanding of the movement of chlorinated organic compounds through aquatic ecosystems, with special emphasis on the differential movement of these compounds due to physical/che...

  7. Developing an Interdisciplinary Curriculum Framework for Aquatic-Ecosystem Modeling

    ERIC Educational Resources Information Center

    Saito, Laurel; Segale, Heather M.; DeAngelis, Donald L.; Jenkins, Stephen H.

    2007-01-01

    This paper presents results from a July 2005 workshop and course aimed at developing an interdisciplinary course on modeling aquatic ecosystems that will provide the next generation of practitioners with critical skills for which formal training is presently lacking. Five different course models were evaluated: (1) fundamentals/general principles…

  8. ABIOTIC TRANSFORMATION PATHWAYS OF ORGANIC CHEMICALS IN AQUATIC ECOSYSTEMS

    EPA Science Inventory

    Information is presented for assessing the potential of an organic chemical to undergo abiotic transformation in aquatic ecosystems. hen predicting the environmental fate of an organic chemical, two primary questions must be addressed. irst, what are the reaction kinetics for the...

  9. AQUATIC ECOSYSTEM MONITORING AND ASSESSMENT ACROSS SCALES

    EPA Science Inventory

    The mission of the United States Environmental Protection Agency (USEPA) is to protect human health and the environment. As part of the Office of Research and Development within the USEPA, the Ecosystems Research Branch of the National Exposure Research Laboratory, located in Ci...

  10. Aquatic Ecosystem Response to Timber Harvesting for the Purpose of Restoring Aspen

    PubMed Central

    Jones, Bobette E.; Krupa, Monika; Tate, Kenneth W.

    2013-01-01

    The removal of conifers through commercial timber harvesting has been successful in restoring aspen, however many aspen stands are located near streams, and there are concerns about potential aquatic ecosystem impairment. We examined the effects of management-scale conifer removal from aspen stands located adjacent to streams on water quality, solar radiation, canopy cover, temperature, aquatic macroinvertebrates, and soil moisture. This 8-year study (2003–2010) involved two projects located in Lassen National Forest. The Pine-Bogard Project consisted of three treatments adjacent to Pine and Bogard Creeks: (i) Phase 1 in January 2004, (ii) Phase 2 in August 2005, and (iii) Phase 3 in January 2008. The Bailey Project consisted of one treatment adjacent to Bailey Creek in September 2006. Treatments involved whole tree removal using track-laying harvesters and rubber tire skidders. More than 80% of all samples analyzed for NO3-N, NH4-N, and PO4-P at Pine, Bogard, and Bailey Creeks were below the detection limit, with the exception of naturally elevated PO4-P in Bogard Creek. All nutrient concentrations (NO3-N, NH4-N, PO4-P, K, and SO4-S) showed little variation within streams and across years. Turbidity and TSS exhibited annual variation, but there was no significant increase in the difference between upstream and downstream turbidity and TSS levels. There was a significant decrease in stream canopy cover and increase in the potential fraction of solar radiation reaching the streams in response to the Pine-Bogard Phase 3 and Bailey treatments; however, there was no corresponding increase in stream temperatures. Macroinvertebrate metrics indicated healthy aquatic ecosystem conditions throughout the course of the study. Lastly, the removal of vegetation significantly increased soil moisture in treated stands relative to untreated stands. These results indicate that, with careful planning and implementation of site-specific best management practices, conifer removal to

  11. Aquatic ecosystem response to timber harvesting for the purpose of restoring aspen.

    PubMed

    Jones, Bobette E; Krupa, Monika; Tate, Kenneth W

    2013-01-01

    The removal of conifers through commercial timber harvesting has been successful in restoring aspen, however many aspen stands are located near streams, and there are concerns about potential aquatic ecosystem impairment. We examined the effects of management-scale conifer removal from aspen stands located adjacent to streams on water quality, solar radiation, canopy cover, temperature, aquatic macroinvertebrates, and soil moisture. This 8-year study (2003-2010) involved two projects located in Lassen National Forest. The Pine-Bogard Project consisted of three treatments adjacent to Pine and Bogard Creeks: (i) Phase 1 in January 2004, (ii) Phase 2 in August 2005, and (iii) Phase 3 in January 2008. The Bailey Project consisted of one treatment adjacent to Bailey Creek in September 2006. Treatments involved whole tree removal using track-laying harvesters and rubber tire skidders. More than 80% of all samples analyzed for NO₃-N, NH₄-N, and PO₄-P at Pine, Bogard, and Bailey Creeks were below the detection limit, with the exception of naturally elevated PO₄-P in Bogard Creek. All nutrient concentrations (NO₃-N, NH₄-N, PO₄-P, K, and SO₄-S) showed little variation within streams and across years. Turbidity and TSS exhibited annual variation, but there was no significant increase in the difference between upstream and downstream turbidity and TSS levels. There was a significant decrease in stream canopy cover and increase in the potential fraction of solar radiation reaching the streams in response to the Pine-Bogard Phase 3 and Bailey treatments; however, there was no corresponding increase in stream temperatures. Macroinvertebrate metrics indicated healthy aquatic ecosystem conditions throughout the course of the study. Lastly, the removal of vegetation significantly increased soil moisture in treated stands relative to untreated stands. These results indicate that, with careful planning and implementation of site-specific best management practices

  12. Measurement of undisturbed di-nitrogen emissions from aquatic ecosystems

    NASA Astrophysics Data System (ADS)

    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.

  13. [Energy flow in arctic aquatic ecosystems

    SciTech Connect

    Schell, D.M.

    1985-12-31

    This study is aimed at determining the major pathways of energy flow in freshwater ecosystems of the Alaskan arctic coastal plain. Selected sites for study of the processes supplying energy to streams and lakes to verify the generality of past findings will be surveyed for collection of organisms including the Colville River drainage and the lake region around Teshekpuk Lake. Specific objectives are to collect food web apex organisms (fish and birds) from a variety of sites in the coastal plain to verify descriptive models of ecosystem structure and food web pathways and to compare the utilization rates by insect larvae of fresh litter and in situ primary production relative to more refractory peaty materials through seasonal sampling for isotopic analysis.

  14. [Energy flow in arctic aquatic ecosystems

    SciTech Connect

    Schell, D.M.

    1985-01-01

    This study is aimed at determining the major pathways of energy flow in freshwater ecosystems of the Alaskan arctic coastal plain. Selected sites for study of the processes supplying energy to streams and lakes to verify the generality of past findings will be surveyed for collection of organisms including the Colville River drainage and the lake region around Teshekpuk Lake. Specific objectives are to collect food web apex organisms (fish and birds) from a variety of sites in the coastal plain to verify descriptive models of ecosystem structure and food web pathways and to compare the utilization rates by insect larvae of fresh litter and in situ primary production relative to more refractory peaty materials through seasonal sampling for isotopic analysis.

  15. A successful closed aquatic ecosystem in SZ-8 mission

    NASA Astrophysics Data System (ADS)

    Li, Xiaoyan; Wang, Gaohong; Richter, Peter; Liu, Yongding; Schuster, Martin; Lebert, Michael

    2012-07-01

    Aquatic ecosystem is a useful means to explore complex interaction among different species, and data got from this kind of system can be used to re-constructer or bio-remedy damaged ecosystem or explore other planet, such as Mars. To deeply investigate interactions of different species in space environment, we established a closed aquatic ecosystem of 60 milliliter with Chlorella, Euglena and Bulinus. As a major oxygen producer, Euglena was put into the lower chamber. The initial concentration of Euglena was adjusted to 40000 cells per milliliter to avoid damage of high oxygen concentration to other organisms. As a secondary oxygen producer and food provider, Chlorella was put into the upper chamber together with 3 bulinus. The initial concentration of Chlorella was 3.2*105 cells per milliliter. After 17.5 days of duration, the system run well with 1 bulinus alive in the spaceflight group and all kept alive in the ground control.

  16. Freshwater ecosystems and aquatic insects: a paradox in biological invasions.

    PubMed

    Fenoglio, Stefano; Bonada, Núria; Guareschi, Simone; López-Rodríguez, Manuel J; Millán, Andrés; Tierno de Figueroa, J Manuel

    2016-04-01

    Biological invasions have increased significantly in response to global change and constitute one of the major causes of biodiversity loss. Insects make up a large fraction of invasive species, in general, and freshwaters are among the most invaded ecosystems on our planet. However, even though aquatic insects dominate most inland waters, have unparalleled taxonomic diversity and occupy nearly all trophic niches, there are almost no invasive insects in freshwaters. We present some hypotheses regarding why aquatic insects are not common among aquatic invasive organisms, suggesting that it may be the result of a suite of biological, ecological and anthropogenic factors. Such specific knowledge introduces a paradox in the current scientific discussion on invasive species; therefore, a more in-depth understanding could be an invaluable aid to disentangling how and why biological invasions occur. PMID:27072403

  17. The carbonate system of the amur estuary and the adjacent marine aquatic areas

    NASA Astrophysics Data System (ADS)

    Koltunov, A. M.; Tishchenko, P. Ya.; Zvalinskii, V. I.; Chichkin, R. V.; Lobanov, V. B.; Nekrasov, D. A.

    2009-10-01

    In July 2007, integrated studies of the Amur Estuary and the adjacent aquatic areas were performed on board R/V Professor Gagarinskii within the project of the Amur River basin exploration. On the basis of the data obtained during the cruise, the carbonate system of the Amur Estuary in the summer period was considered. It was shown that the distribution of the carbonate parameters in the Amur Estuary and the adjacent aquatic areas points to the high intensity of the bio-geochemical processes of production and mineralization of organic matter. It was found that the organic matter destruction is prevailing over the photosynthesis in the riverine part of the estuary. This aquatic area is a source of carbon dioxide for the atmosphere and rates as a heterotrophic basin. On the contrary, the surface waters at the outer boundaries of the estuary (the Gulf of Sakhalin and the Tatar Strait) act as a sink of the atmospheric carbon dioxide, which is caused by the intense photosynthesis in this area. This part of the estuary is treated as an autotrophic basin.

  18. Global ecological impacts of invasive species in aquatic ecosystems.

    PubMed

    Gallardo, Belinda; Clavero, Miguel; Sánchez, Marta I; Vilà, Montserrat

    2016-01-01

    alteration). Considering the strong trophic links that characterize aquatic ecosystems, this framework is relevant to anticipate the far-reaching consequences of biological invasions on the structure and functionality of aquatic ecosystems. PMID:26212892

  19. Aquatic ecosystem condition: The Fraser River Action Plan approach

    SciTech Connect

    Tuominen, T.; Raymond, B.; Sekela, M.; Reynoldson, T.

    1995-12-31

    A major goal of the Canadian government`s Fraser River Action Plan (FRAP) is to clean up existing pollution problems in the Fraser River Basin. In support of this goal, the Environmental Quality Assessment Program is assessing the quality of the aquatic environment, particularly with respect to contaminants. The program, conducted from 1993 to 1998, is to establish a baseline condition for the aquatic ecosystem against which the success of clean up efforts can be measured. The FRAP approach is to use a combination of contaminant exposure or stressor indicators and organism ``effects`` indicators. The focus is on three components of the aquatic ecosystem: (1) bed sediment, (2) resident fish and (3) benthos. A priority for the program is integration of the three components, wherever possible. Bed sediments, as indicators of contaminant stress, are sampled at fourteen reaches in the river and major tributaries. Two species of resident fish are sampled and analyzed for condition factors, enzyme induction, histopathology and contaminant content at each of nine sites in the basin. The resident fish data are providing a measure of contaminant exposure and effect. Organism community effects will be assessed by a study which is classifying approximately 200 tributary and mainstem sites based on benthos community structure. For the first time in a large river system in Canada, this benthos study uses a multivariate approach which relates a suite of chemical and physical characteristics to benthos community structure.

  20. Aquatic biodiversity in forests: A weak link in ecosystem services resilience

    USGS Publications Warehouse

    Penaluna, Brooke E.; Olson, Deanna H.; Flitcroft, Rebecca L; Weber, Matthew A.; Bellmore, James R.; Wondzell, Steven M.; Dunham, Jason; Johnson, Sherri L.; Reeves, Gordon H.

    2016-01-01

    The diversity of aquatic ecosystems is being quickly reduced on many continents, warranting a closer examination of the consequences for ecological integrity and ecosystem services. Here we describe intermediate and final ecosystem services derived from aquatic biodiversity in forests. We include a summary of the factors framing the assembly of aquatic biodiversity in forests in natural systems and how they change with a variety of natural disturbances and human-derived stressors. We consider forested aquatic ecosystems as a multi-state portfolio, with diverse assemblages and life-history strategies occurring at local scales as a consequence of a mosaic of habitat conditions and past disturbances and stressors. Maintaining this multi-state portfolio of assemblages requires a broad perspective of ecosystem structure, various functions, services, and management implications relative to contemporary stressors. Because aquatic biodiversity provides multiple ecosystem services to forests, activities that compromise aquatic ecosystems and biodiversity could be an issue for maintaining forest ecosystem integrity. We illustrate these concepts with examples of aquatic biodiversity and ecosystem services in forests of northwestern North America, also known as Northeast Pacific Rim. Encouraging management planning at broad as well as local spatial scales to recognize multi-state ecosystem management goals has promise for maintaining valuable ecosystem services. Ultimately, integration of information from socio-ecological ecosystems will be needed to maintain ecosystem services derived directly and indirectly from forest aquatic biota.

  1. DEVELOPMENT OF A DISTURBANCE INDEX TO ASSESS THE CONDITION OF AQUATIC ECOSYSTEMS

    EPA Science Inventory

    An objective of aquatic monitoring is to assess the condition of aquatic habitats and biota. To rationally interpret aquatic condition, we must identify the range of human activities and the risks they pose to aquatic ecosystems. Placing stream reaches and their watersheds on a...

  2. Physical Thresholds as Ecological Proxies in Aquatic Ecosystems

    NASA Astrophysics Data System (ADS)

    Hausner, M. B.; Gaines, D. B.; Morrison, R. R.; Sada, D. W.; Scoppettone, G. G.; Stone, M. C.; Suarez, F. I.; Tyler, S. W.; Wilson, K. P.

    2015-12-01

    It is often difficult to directly quantify ecological thresholds and predict ecological responses to changing environmental conditions. Here, we present two case studies from Death Valley National Park - Devils Hole and Travertine Springs - in which physical parameters are used as proxies for ecological processes to assess the consequences of environmental change on aquatic ecosystems. In Devils Hole, seasonal thresholds for water temperature and food availability are defined to quantify the optimal recruitment window for the Devils Hole pupfish (Cyprinodon diabolis). At Travertine Springs, physical thresholds of water depth, velocity, and temperature are used to define the spatial extent of the preferred habitat of several threatened macroinvertebrate species. In both systems, mechanistic models are developed to predict the response of those physical thresholds to changing environmental conditions informed by climate change scenarios and potential changes in water availability. By examining the temporal and spatial response of targeted physical parameters to alternative scenarios, we can assess potential ecosystem impacts without direct measurement of ecological processes.

  3. Three month performances of Closed Aquatic Ecosystem on ground

    NASA Astrophysics Data System (ADS)

    Wang, Gaohong; Hao, Zongjie; Hu, Chunxiang; Liu, Yongding

    A Closed Aquatic Ecosystem (CAES) was developed to study on performance of closed ecosystems for three month as a preparation for future spaceflight experiments. The system housed three small freshwater snails (Bulinus australianus) and autotrophic green algae (Chlorella pyrenoidosa) in a 500mL box with light and temperature control. The special sensors for pH value, oxygen concentration, biomass, temperature and light were developed for long-time performance. It was found that algae biomass increased for several days and then leveled off, and light and temperature control indicated normally, pH and oxygen concentration was affect by light cycle but they met the snails' requirement for live. After three month experiment, the snails survive successfully and laid some eggs in box, and the atmosphere and biomass for food were met snails' requirement. The results on ground demonstrated the biological stability and technical reliability for future spaceflight experiment.

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

    PubMed

    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. PMID:27534952

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

    PubMed Central

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

    2016-01-01

    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. PMID:27534952

  6. Environmental bacteriophages: viruses of microbes in aquatic ecosystems

    PubMed Central

    Sime-Ngando, Télesphore

    2014-01-01

    Since the discovery 2–3 decades ago that viruses of microbes are abundant in marine ecosystems, viral ecology has grown increasingly to reach the status of a full scientific discipline in environmental sciences. A dedicated ISVM society, the International Society for Viruses of Microorganisms, (http://www.isvm.org/) was recently launched. Increasing studies in viral ecology are sources of novel knowledge related to the biodiversity of living things, the functioning of ecosystems, and the evolution of the cellular world. This is because viruses are perhaps the most diverse, abundant, and ubiquitous biological entities in the biosphere, although local environmental conditions enrich for certain viral types through selective pressure. They exhibit various lifestyles that intimately depend on the deep-cellular mechanisms, and are ultimately replicated by members of all three domains of cellular life (Bacteria, Eukarya, Archaea), as well as by giant viruses of some eukaryotic cells. This establishes viral parasites as microbial killers but also as cell partners or metabolic manipulators in microbial ecology. The present chapter sought to review the literature on the diversity and functional roles of viruses of microbes in environmental microbiology, focusing primarily on prokaryotic viruses (i.e., phages) in aquatic ecosystems, which form the bulk of our knowledge in modern environmental viral ecology. PMID:25104950

  7. Environmental bacteriophages: viruses of microbes in aquatic ecosystems.

    PubMed

    Sime-Ngando, Télesphore

    2014-01-01

    Since the discovery 2-3 decades ago that viruses of microbes are abundant in marine ecosystems, viral ecology has grown increasingly to reach the status of a full scientific discipline in environmental sciences. A dedicated ISVM society, the International Society for Viruses of Microorganisms, (http://www.isvm.org/) was recently launched. Increasing studies in viral ecology are sources of novel knowledge related to the biodiversity of living things, the functioning of ecosystems, and the evolution of the cellular world. This is because viruses are perhaps the most diverse, abundant, and ubiquitous biological entities in the biosphere, although local environmental conditions enrich for certain viral types through selective pressure. They exhibit various lifestyles that intimately depend on the deep-cellular mechanisms, and are ultimately replicated by members of all three domains of cellular life (Bacteria, Eukarya, Archaea), as well as by giant viruses of some eukaryotic cells. This establishes viral parasites as microbial killers but also as cell partners or metabolic manipulators in microbial ecology. The present chapter sought to review the literature on the diversity and functional roles of viruses of microbes in environmental microbiology, focusing primarily on prokaryotic viruses (i.e., phages) in aquatic ecosystems, which form the bulk of our knowledge in modern environmental viral ecology. PMID:25104950

  8. ELF communications system ecological monitoring program: Aquatic ecosystem studies

    NASA Astrophysics Data System (ADS)

    Burton, Thomas M.; Stout, R. J.; Winterstein, Scott; Coon, Thomas; Novinger, Doug

    1994-11-01

    The U.S. Navy has completed a program that monitored biota and ecological miationships for possible effects from electromagnetic (EM) fields produced by its Extremely Low Frequency (ELF) Communications System. This report documents the results and conclusions of aquatic studies conducted near its transmitting antenna in Michigan. From 1982 through 1993 researchers from the Michigan State University (MSU) monitored aquatic flora and fauna on matched reaches of the Ford River. A treatment site was located immediately adjacent to the antenna, whereas a control site was situated at a distance downstream. Functional and structural components of the periphyton, insect, and fish communities were monitored. The research team also measured ambient factors such as temperature, discharge, and water quality indicators. Data were analyzed using a variety of statistical tests; however, BACI techniques were emphasized. Results indicated a relative increase in algal biomass at the treatment site after the antenna became fully operational, but no changes in any other parameter or organism. MSU concludes that algal biomass was affected by ELF EM exposure. Since neither the other ecological characteristics of the periphyton nor the insect and fish communities showed any effects, MSU infers little EM impact to riverine habitats.

  9. Guided Inquiry Learning Unit on Aquatic Ecosystems for Seventh Grade Students

    ERIC Educational Resources Information Center

    To-im, Jongdee; Ruenwongsa, Pintip

    2009-01-01

    Using mini-aquaria experiments, a learning unit on the effects of light period on aquatic ecosystems was developed for 7th grade students. This guided inquiry unit was aimed at helping students understand basic ecological principles involved in relationships among physical, chemical, and biological components in aquatic ecosystems. It involved…

  10. Selection of candidate aquatic high plants as producer of closed aquatic ecosystem

    NASA Astrophysics Data System (ADS)

    Wang, Gaohong; Hao, Zongjie; Liu, Yongding

    Controlled Ecological Life Support Systems (CELSS) is very important for long-term manned space flight. Aquatic organism was regarded to be suitable for this study because of their great adaptation to the weightless condition which approximate to their wild condition in water. In order to study of operation of CELSS in space, the first step is to choose good candidate species for study. In this report, we compared the characteristics of nutrient content, growth and suitability with animals among five types of aquatic high plants including Ceratophyllum demersum L., Vallisneria spiralis L., Hydrilla verticillata Royle, Brasenia schreberi, Wolfia arrhiza under control condition. It was found that B. schreberi had the best nutrients content, but it growth depended on gas interface which may be a big problem in microgravity. C. demersum and W. arrhiza had the better nutrient content than other types, and V. spiralis and H. verticillata had the worst nutrient content. The closed aquatic system can provided condition for the growth of other plants than B. schreberi. So we selected C. demersum and W. arrhiza as the candidate of producer for establish Closed Aquatic Ecosystem. We also established a simple system& by housing three small freshwater snails (Bulinus australianus) and C. demersum in a 500mL box with light and temperature control. The values about pH, oxygen concentration, temperature and light had been acquired by sensors in real time for about 3 month. It was found that plant's biomass increased for several days and then leveled off and the snails survive, and the atmosphere and biomass for food met snails' requirement during experiments.

  11. Ecological Relationships Between Components in Closed Aquatic Ecosystems

    NASA Astrophysics Data System (ADS)

    Pisman, Tamara; Somova, Lydia

    The work considers the problems of relationships between algae and other microorganisms in aquatic ecosystems. Using small-scale laboratory "autotroph-heterotroph" ecosystems with different types of closure, we showed the results of the investigation into the ecological relation-ships of algae in biocenoses. The autotrophic component was represented by green microalgae, and the heterotrophic component -by yeast and bacteria. An important role in functioning of algobacterial communities is played by 2 -2 (oxygen -carbon dioxide) exchange. The gas exchange between algae and yeast was studied in the "autotroph-heterotroph" gas-closed ecosystem with space-divided components. It was shown that the gas exchange closure of the components into a system prolongs its existence. Hav-ing increased the degree of the system closure by introducing two yeast species with positive metabolic interaction to the heterotrophic component, we observed a significant increase in the gas exchange between the components and thus in the biomass of algae and yeast. The most ancient and ecologically relevant symbioses known in nature are symbiotic associa-tions of algae and heterotrophic organisms. The main symbionts of algae in aquatic ecosystems are bacteria. The cenosis-forming role of algae is based on two characteristics: firstly, their mucous covers and membranes are able to absorb and retain large amounts of water; secondly, many algae evolve various organic substances during their lifetime. An example of algobacterial associations are microalgae Chlorella vulgaris and accompanying microbial flora. Experiments with non-sterile batch culture of algae showed that the increase in the algae biomass was accompanied by the increase in the bacterial biomass. As a result of theoretical and experi-mental investigation into their relationships, it was shown that the largest biomass of bacteria is achieved when using organic substances evolved by algae and having bacteria grow on dead algae; i

  12. Developing Meaningful Measures and Guidelines for Particulates in Aquatic Ecosystems

    NASA Astrophysics Data System (ADS)

    Bilotta, G. S.; Harrison, C.; Joyce, C.; Peacock, C.

    2010-12-01

    Managing global water resources is one of the greatest challenges of the 21st Century. It is a resource that is under growing pressure as global populations rise and the natural supply, in the form of precipitation, is becoming increasingly variable and uncertain with climate change. It is therefore essential that water resources (surface and groundwaters) are managed sustainably in terms of both their quantity and quality. One of the most common causes for the impairment of water quality in surface waters and groundwaters is the presence of particulate matter. Particulate matter, from nano-scale particles and colloids to silt-sized sediments, can have a range of detrimental effects on water resources, from aesthetic issues and higher costs of water treatment, to a decline in the fisheries resource and serious ecological degradation. However at present, there is a poor understanding of the particulate conditions that water quality managers should aim to achieve in order to support good ecological status in different environments. There is also currently a general lack of rigour and standardisation in measurements of particulate matter in aquatic ecosystems, which in turn limits our understanding of the effects of these particles, and importantly, limits our ability to guide effective remediation. This poster describes a research approach that is currently being developed in the UK to address these issues; supporting (1) the development of ecosystem-specific water quality guidelines for particulate matter, and (2) the innovation of more advanced monitoring technologies for particulate matter in aquatic environments. The research project will utilise an established network of 13 reference condition sites (i.e. sites that have minimal anthropogenic disturbance) that contain distinct aquatic communities and are located in contrasting environment types. Hydrological and biological monitoring will be carried-out concurrently with analysis of the physical and geochemical

  13. Human health-related ecosystem services of avian-dense coastal wetlands adjacent to a Western Lake Erie swimming beach.

    PubMed

    Rea, Chris L; Bisesi, Michael S; Mitsch, William; Andridge, Rebecca; Lee, Jiyoung

    2015-03-01

    Wetlands provide many valuable ecosystem services, including water quality improvement to protect downstream aquatic ecosystems such as lakes, rivers, and estuaries. However, their ability to improve water quality to safe levels for direct human exposure while largely surrounded by agricultural lands and hosting large wildlife populations remains unknown. Our aim was to examine the ecosystem service capabilities of an avian-dense coastal wetland surrounded by agricultural lands along the southwestern shore of Lake Erie in Ohio by assessing the quality of water as it flows through the wetland (Ottawa National Wildlife Refuge (ONWR)) and into Lake Erie beach waters. Our study used total phosphorus and fecal indicator (Escherichia coli) concentrations as water quality metrics across the wetland and at an adjacent Lake Erie swimming beach during the 2012 summer swim season. E. coli and total P levels were consistently highest at the site, where water enters the ONWR (mean E. coli = 507 CFU/100 mL; mean total P = 535 μg/L), and steadily decreased as water flowed through the wetland and into the adjacent beach (mean E. coli = 10 CFU/100 mL; mean total P = 41 μg/L). E. coli and total P showed statistically significant (α = 0.01) correlations with phycocyanin, chlorophyll-a, turbidity, specific conductivity, dissolved oxygen, and pH; total P was also significantly correlated with total N. The results suggest that this wetland may be contributing to improving water quality, which is beneficial for human health as well as to downstream ecosystem health (e.g., limiting eutrophication promoting conditions, etc.). PMID:25582638

  14. The Closed Equilibrated Biological Aquatic System: A 12 months Test of an Artificial Aquatic Ecosystem

    NASA Astrophysics Data System (ADS)

    Blüm, V.; Andriske, M.; Ludwig, Ch.; Paaßen, U.; Voeste, D.

    1999-01-01

    The ``Closed Equilibrated Biological Aquatic System'' (C.E.B.A.S.) is finally disposed for long-term multi-generation experiments with aquatic organisms in a space station. Therefore a minimum operation time of three month is required. It is verified in three versions of laboratory prototypes. The third one passed successfully a 12 months mid-term test in 1995/96 thus demonstrating its high biological stability. The third version of the C.E.B.A.S. consists of a 100 l animal tank, two plant cultivators with a volume of 15 l each with independent illuminations, a 3.0 l semibiological ``mechanical'' filter, a 3.0 l bacteria filter, a heating/cooling device and a dummy filter unit. The live-bearing teleost Xiphophorus helleri is the vertebrate and the pulmonate water snail Biomphalaria glabrata the invertebrate experimental animal in the system. The rootless higher water plant Ceratophyllum demersum is the producer organism. Ammonia oxidizing bacteria and other microorganisms settle in the filters. A simple data acquisition is combined with temperature and plant illumination control. Besides of the space aspects the C.E.B.A.S. proved to be an extremely suitable tool to investigate the organism and subcomponent interactions in a well defined terrestrial aquatic closed ecosystem by providing physical, chemical and biological data which allow an approach to a comprehensive system analysis. Moreover the C.E.B.A.S. is the base for the development of innovative combined animal-plant aquaculture systems for human nutrition on earth which could be implemented into bioregenerative life support systems with a higher degree of complexity suitable for lunar or planetary bases.

  15. Fire and aquatic ecosystems of the western USA: Current knowledge and key questions

    USGS Publications Warehouse

    Bisson, P.A.; Rieman, B.; Luce, C.; Hessburg, Paul F.; Lee, D.; Kershner, J.; Reeves, G.H.; Gresswell, Robert E.

    2003-01-01

    Understanding of the effects of wildland fire and fire management on aquatic and riparian ecosystems is an evolving field, with many questions still to be resolved. Limitations of current knowledge, and the certainty that fire management will continue, underscore the need to summarize available information. Integrating fire and fuels management with aquatic ecosystem conservation begins with recognizing that terrestrial and aquatic ecosystems are linked and dynamic, and that fire can play a critical role in maintaining aquatic ecological diversity. To protect aquatic ecosystems we argue that it will be important to: (1) accommodate fire-related and other ecological processes that maintain aquatic habitats and biodiversity, and not simply control fires or fuels; (2) prioritize projects according to risks and opportunities for fire control and the protection of aquatic ecosystems; and (3) develop new consistency in the management and regulatory process. Ultimately, all natural resource management is uncertain; the role of science is to apply experimental design and hypothesis testing to management applications that affect fire and aquatic ecosystems. Policy-makers and the public will benefit from an expanded appreciation of fire ecology that enables them to implement watershed management projects as experiments with hypothesized outcomes, adequate controls, and replication.

  16. Acid deposition in aquatic ecosystems: Setting limits empirically

    NASA Astrophysics Data System (ADS)

    Newcombe, Charles P.

    1985-07-01

    The problem of acid deposition and its harmful effects on aquatic ecosystems has created a new branch of science that is called upon to provide the knowledge on which legislative controls can be based. However, because of the nature of existing legislation, which requires evidence of cause and effect between industrial emissions and pollution, and because of science's inability to provide this information over the short term, considerable controversy has arisen about whether sufficient information exists to warrant control measures at this time. Among those who advocate controls, there is genuine divergence of opinion about how stringent the controls must be to achieve any desired level of protection. The controversy has led to an impasse between the scientific and political participants, which is reflected in the slow pace of progress toward an effective management strategy. Resolution of the impasse, at least in the short term, may demand that science and politics rely on empirical models rather than explanatory ones. The empirical model, which is the major proposal in this article, integrates all of the major variables and many of the minor ones, and constructs a three-dimensionally curved surface capable of representing the status of any waterbody subjected to the effects of acid deposition. When suitably calibrated—a process involving the integration of knowledge and data from aquatic biology, geochemistry, meteorology, and limnology—it can be used to depict limits to the rate of acid deposition required for any level of environmental protection. Because it can generate a pictorial display of the effects of management decisions and legislative controls, the model might serve as a basis for enhancing the quality of communication among all the scientific and political participants and help to resolve many of their controversies.

  17. Aquatic Ecosystem Enhancement at Mountaintop Mining Sites Symposium

    SciTech Connect

    Black, D. Courtney; Lawson, Peter; Morgan, John; Maggard, Randy; Schor, Horst; Powell, Rocky; Kirk, Ed. J.

    2000-01-12

    Welcome to this symposium which is part of the ongoing effort to prepare an Environmental Impact Statement (EIS) regarding mountaintop mining and valley fills. The EIS is being prepared by the U.S. Environmental Protection Agency, U.S. Army Corps of Engineers, U.S. Office of Surface Mining, and U.S. Fish and Wildlife Service, in cooperation with the State of West Virginia. Aquatic Ecosystem Enhancement (AEE) at mountaintop mining sites is one of fourteen technical areas identified for study by the EIS Interagency Steering Committee. Three goals were identified in the AEE Work Plan: 1. Assess mining and reclamation practices to show how mining operations might be carried out in a way that minimizes adverse impacts to streams and other environmental resources and to local communities. Clarify economic and technical constraints and benefits. 2. Help citizens clarify choices by showing whether there are affordable ways to enhance existing mining, reclamation, mitigation processes and/or procedures. 3. Ide identify data needed to improve environmental evaluation and design of mining projects to protect the environment. Today’s symposium was proposed in the AEE Team Work Plans but coordinated planning for the event began September 15, 1999 when representatives from coal industry, environmental groups and government regulators met in Morgantown. The meeting participants worked with a facilitator from the Canaan Valley Institute to outline plans for the symposium. Several teams were formed to carry out the plans we outlined in the meeting.

  18. Performance of a simple closed aquatic ecosystem (CAES) in space

    NASA Astrophysics Data System (ADS)

    Wang, G.-H.; Li, G.-B.; Hu, C.-X.; Liu, Y.-D.; Song, L.-R.; Tong, G.-H.; Liu, X.-M.; Cheng, E.-T.

    2004-01-01

    A simple Closed Aquatic Ecosystem (CAES) consisting of single-celled green algae ( Chlorella pyrenoidosa, producer), a spiral snail ( Bulinus australianus, consumer) and a data acquisition and control unit was flown on the Chinese Spacecraft SHENZHOU-II in January 2001 for 7 days. In order to study the effect of microgravity on the operation of CAES, a 1 g centrifuge reference group in space, a ground 1 g reference group and a ground 1 g centrifuge reference group (1.4 g group) were run concurrently. Real-time data about algae biomass (calculated from transmission light intensity), temperature, light and centrifugation of the CAES were logged at minute intervals. It was found that algae biomass of both the microgravity group and the ground 1 g centrifuge reference group (1.4 g) fluctuated during the experiment, but the algae biomass of the 1 g centrifuge reference group in space and the ground 1 g reference group increased during the experiment. The results may be attributable to influences of microgravity and 1.4 g gravity on the algae and snails metabolisms. Microgravity is the main factor to affect the operation of CAES in space and the contribution of microgravity to the effect was also estimated. These data may be valuable for the establishment of a complex CELSS in the future.

  19. Effects of solar UV-B radiation on aquatic ecosystems

    NASA Astrophysics Data System (ADS)

    Häder, D.-P.

    Solar UV degrades dissolved organic carbon photolytically so that they can readily be taken up by bacterioplankton. On the other hand solar UV radiation inhibits bacterioplankton activity. Bacterioplankton productivity is far greater than previously thought and is comparable to phytoplankton primary productivity. According to the "microbial loop hypothesis," bacterioplankton is seen in the center of a food web, having a similar function to phytoplankton and protists. The penetration of UV and PAR into the water column can be measured. Marine waters show large temporal and regional differences in their concentrations of dissolved and particulate absorbing substances. A network of dosimeters (ELDONET) has been installed in Europe ranging from Abisko in Northern Sweden to Gran Canaria. Cyanobacteria are capable of fixing atmospheric nitrogen which is then made available to higher plants. The agricultural potential of cyanobacteria has been recognized as a biological fertilizer for wet soils such as in rice paddies. UV-B is known to impair processes such as growth, survival, pigmentation, motility, as well as the enzymes of nitrogen metabolism and CO 2 fixation. The marine phytoplankton represents the single most important ecosystem on our planet and produces about the same biomass as all terrestrial ecosystems taken together. It is the base of the aquatic food chain and any changes in the size and composition of phytoplankton communities will directly affect food production for humans from marine sources. Another important role of marine phytoplankton is to serve as a sink for atmospheric carbon dioxide. Recent investigations have shown a large sensitivity of most phytoplankton organisms toward solar short-wavelength ultraviolet radiation (UV-B); even at ambient levels of UV-B radiation many organisms seem to be under UV stress. Because of their requirement for solar energy, the phytoplankton dwell in the top layers of the water column. In this near-surface position

  20. Effects of solar UV-B radiation on aquatic ecosystems.

    PubMed

    Hader, D P

    2000-01-01

    Solar UV degrades dissolved organic carbon photolytically so that they can readily be taken up by bacterioplankton. On the other hand solar UV radiation inhibits bacterioplankton activity. Bacterioplankton productivity is far greater than previously thought and is comparable to phytoplankton primary productivity. According to the "microbial loop hypothesis," bacterioplankton is seen in the center of a food web, having a similar function to phytoplankton and protists. The penetration of UV and PAR into the water column can be measured. Marine waters show large temporal and regional differences in their concentrations of dissolved and particulate absorbing substances. A network of dosimeters (ELDONET) has been installed in Europe ranging from Abisko in Northern Sweden to Gran Canaria. Cyanobacteria are capable of fixing atmospheric nitrogen which is then made available to higher plants. The agricultural potential of cyanobacteria has been recognized as a biological fertilizer for wet soils such as in rice paddies. UV-B is known to impair processes such as growth, survival, pigmentation, motility, as well as the enzymes of nitrogen metabolism and CO2 fixation. The marine phytoplankton represents the single most important ecosystem on our planet and produces about the same biomass as all terrestrial ecosystems taken together. It is the base of the aquatic food chain and any changes in the size and composition of phytoplankton communities will directly affect food production for humans from marine sources. Another important role of marine phytoplankton is to serve as a sink for atmospheric carbon dioxide. Recent investigations have shown a large sensitivity of most phytoplankton organisms toward solar short-wavelength ultraviolet radiation (UV-B); even at ambient levels of UV-B radiation many organisms seem to be under UV stress. Because of their requirement for solar energy, the phytoplankton dwell in the top layers of the water column. In this near-surface position

  1. Determining the Effectiveness of Aquatic Ecosystem Restoration, Conservation, and Management Practices.

    EPA Science Inventory

    The science of aquatic ecosystem restoration and management is still in its infancy, largely because most projects are inadequately tracked and monitored for assessing their success. Historically, evaluating the effectiveness of best management practices (BMPs) has relied heavily...

  2. UV EFFECTS ON MARINE AND AQUATIC ECOSYSTEMS. IN: PHOTOBIOLOGY FOR THE 21ST CENTURY.

    EPA Science Inventory

    Authors present a review of the literature dealing with UV effects on marine and aquatic ecosystems. Topic headings include Direct Effects, Interactive Effects, Indirect Effects, Response Variability, and The Future.

  3. CONCEPTUAL MODELS AND METHODS TO GUIDE DIAGNOSTIC RESEARCH INTO CAUSES OF IMPAIRMENT TO AQUATIC ECOSYSTEMS

    EPA Science Inventory

    Methods and conceptual models to guide the development of tools for diagnosing the causes of biological impairment within aquatic ecosystems of the United States are described in this report. The conceptual models developed here address nutrients, suspended and bedded sediments (...

  4. Geologic sources of nutrients for aquatic ecosystems (Invited)

    NASA Astrophysics Data System (ADS)

    Dahlgren, R. A.; Jeffres, C.; Nichols, A. L.; Deas, M.; Willis, A.; Mount, J.

    2010-12-01

    Nutrient inputs from geologic materials are not typically considered an ecologically significant source of nutrients for freshwater aquatic ecosystems. However, in volcanic terrains where regional groundwater interacts with volcanic and underlying sedimentary deposits, nutrients (nitrogen and phosphorus) from geologic sources can provide ecologically significant inputs of nutrients to fuel aquatic food webs. The Big Springs-Shasta River complex emanating from the flanks of Mt. Shasta, a stratovolcano in northern California, creates a unique ecological niche that we propose as the explanation for the exceptionally high historical abundances and productivity of salmonids in the Shasta River. The Big Springs complex is a slightly-thermal springs (natural flow of 2.6 m3/s) that is the primary source of water for the Shasta River. The spring waters have a mean recharge elevation of 2880 m on Mt. Shasta. During the 20-50 years of transport as groundwater, both nitrogen and phosphorus are released from the underlying marine sedimentary and volcanic rocks. Mean NO3-N and soluble-reactive PO4-P concentrations over a two year period were 0.48 mg/L and 0.15 mg/L, respectively. The PO4 concentrations are in equilibrium with hydroxyapatite (Ca2OHPO4) suggesting that release of PO4 by chemical weathering of the highly weatherable volcanic deposits is the primary source of the PO4. The primary source of nitrogen is from detrital organic matter incorporated in the marine sedimentary rocks during diagensis. This “geologic” nitrogen is released from rocks by hydrothermal waters and transported with the groundwater. The nitrogen and phosphorus coupled with year round consistent water flow volumes and thermal buffering (10-12o C) fuel primary productivity and enhance food web productivity. Abundant nutrients allow for high rates of primary productivity, providing food for invertebrates, which ultimately comprise the primary food source for salmonids. These volcanic-derived, spring

  5. Concentrated standing tailwater: a mechanism for nutrient delivery to downstream aquatic ecosystems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Contribution of first flush runoff events from intense rainfall to downstream aquatic ecosystems are often reported in terms of sediment and nutrient delivery, with hardly any consideration to the contribution that standing, concentrated tailwater in primary aquatic systems makes to downstream nutri...

  6. MICROBIAL INDICATORS OF AQUATIC ECOSYSTEM CHANGE: CURRENT APPLICATIONS TO EUTROPHICATION STUDIES. (R828677C001)

    EPA Science Inventory

    Human encroachment on aquatic ecosystems is increasing at an unprecedented rate. The impacts of human pollution and habitat alteration are most evident and of greatest concern at the microbial level, where a bulk of production and nutrient cycling takes place. Aquatic ecosyste...

  7. 75 FR 18499 - The Effects of Mountaintop Mines and Valley Fills on Aquatic Ecosystems of the Central...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-12

    ... Coalfields and a Field-Based Aquatic Life Benchmark for Conductivity in Central Appalachian Streams AGENCY...) ``A Field-based Aquatic Life Benchmark for Conductivity in Central Appalachian Streams'' (EPA/600/R... Fills on Aquatic Ecosystems of the Central Appalachian Coalfields'' and ``A Field-based Aquatic...

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

    ERIC Educational Resources Information Center

    Simpson, James R.

    This module is part of a series on Physical Processes in Terrestrial and Aquatic Ecosystems. The materials were designed to be used by life science students for instruction in the application of physical theory to ecosystem operation. Most modules contain computer programs which are built around a particular application of a physical process.…

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

    ERIC Educational Resources Information Center

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

    These materials were designed to be used by life science students for instruction in the application of physical theory to ecosystem operation. Most modules contain computer programs which are built around a particular application of a physical process. Primary production in aquatic ecosystems is carried out by phytoplankton, microscopic plants…

  10. Stimulation of microbial nitrogen cycling in aquatic ecosystems by benthic macrofauna: mechanisms and environmental implications

    NASA Astrophysics Data System (ADS)

    Stief, P.

    2013-12-01

    Invertebrate animals that live at the bottom of aquatic ecosystems (i.e., benthic macrofauna) are important mediators between nutrients in the water column and microbes in the benthos. The presence of benthic macrofauna stimulates microbial nutrient dynamics through different types of animal-microbe interactions, which potentially affect the trophic status of aquatic ecosystems. This review contrasts three types of animal-microbe interactions in the benthos of aquatic ecosystems: (i) ecosystem engineering, (ii) grazing, and (iii) symbiosis. Their specific contributions to the turnover of fixed nitrogen (mainly nitrate and ammonium) and the emission of the greenhouse gas nitrous oxide are evaluated. Published data indicate that ecosystem engineering by sediment-burrowing macrofauna stimulates benthic nitrification and denitrification, which together allows fixed nitrogen removal. However, the release of ammonium from sediments is enhanced more strongly than the sedimentary uptake of nitrate. Ecosystem engineering by reef-building macrofauna increases nitrogen retention and ammonium concentrations in shallow aquatic ecosystems, but allows organic nitrogen removal through harvesting. Grazing by macrofauna on benthic microbes apparently has small or neutral effects on nitrogen cycling. Animal-microbe symbioses provide abundant and distinct benthic compartments for a multitude of nitrogen-cycle pathways. Recent studies reveal that ecosystem engineering, grazing, and symbioses of benthic macrofauna significantly enhance nitrous oxide emission from shallow aquatic ecosystems. The beneficial effect of benthic macrofauna on fixed nitrogen removal through coupled nitrification-denitrification can thus be offset by the concurrent release of (i) ammonium that stimulates aquatic primary production and (ii) nitrous oxide that contributes to global warming. Overall, benthic macrofauna intensifies the coupling between benthos, pelagial, and atmosphere through enhanced turnover and

  11. Stimulation of microbial nitrogen cycling in aquatic ecosystems by benthic macrofauna: mechanisms and environmental implications

    NASA Astrophysics Data System (ADS)

    Stief, P.

    2013-07-01

    Invertebrate animals that live at the bottom of aquatic ecosystems (i.e., benthic macrofauna) are important mediators between nutrients in the water column and microbes in the benthos. The presence of benthic macrofauna stimulates microbial nutrient dynamics through different types of animal-microbe interactions, which potentially affect the trophic status of aquatic ecosystems. This review contrasts three types of animal-microbe interactions in the benthos of aquatic ecosystems: (i) ecosystem engineering, (ii) grazing, and (iii) symbiosis. Their specific contributions to the turnover of fixed nitrogen (mainly nitrate and ammonium) and the emission of the greenhouse gas nitrous oxide are evaluated. Published data indicate that ecosystem engineering by sediment-burrowing macrofauna stimulates benthic nitrification and denitrification, which together allows fixed nitrogen removal. However, the release of ammonium from sediments often is enhanced even more than the sedimentary uptake of nitrate. Ecosystem engineering by reef-building macrofauna increases nitrogen retention and ammonium concentrations in shallow aquatic ecosystems, but allows organic nitrogen removal through harvesting. Grazing by macrofauna on benthic microbes apparently has small or neutral effects on nitrogen cycling. Animal-microbe symbioses provide abundant and distinct benthic compartments for a multitude of nitrogen-cycle pathways. Recent studies revealed that ecosystem engineering, grazing, and symbioses of benthic macrofauna significantly enhance nitrous oxide emission from shallow aquatic ecosystems. The beneficial effect of benthic macrofauna on fixed nitrogen removal through coupled nitrification-denitrification can thus be offset by the concurrent release of (i) ammonium that stimulates aquatic primary production and (ii) nitrous oxide that contributes to global warming. Overall, benthic macrofauna intensifies the coupling between benthos, pelagial, and atmosphere through enhanced turnover

  12. Lowering the Barriers to Integrative Aquatic Ecosystem Science: Semantic Provenance, Open Linked Data, and Workflows

    NASA Astrophysics Data System (ADS)

    Harmon, T.; Hofmann, A. F.; Utz, R.; Deelman, E.; Hanson, P. C.; Szekely, P.; Villamizar, S. R.; Knoblock, C.; Guo, Q.; Crichton, D. J.; McCann, M. P.; Gil, Y.

    2011-12-01

    Environmental cyber-observatory (ECO) planning and implementation has been ongoing for more than a decade now, and several major efforts have recently come online or will soon. Some investigators in the relevant research communities will use ECO data, traditionally by developing their own client-side services to acquire data and then manually create custom tools to integrate and analyze it. However, a significant portion of the aquatic ecosystem science community will need more custom services to manage locally collected data. The latter group represents enormous intellectual capacity when one envisions thousands of ecosystems scientists supplementing ECO baseline data by sharing their own locally intensive observational efforts. This poster summarizes the outcomes of the June 2011 Workshop for Aquatic Ecosystem Sustainability (WAES) which focused on the needs of aquatic ecosystem research on inland waters and oceans. Here we advocate new approaches to support scientists to model, integrate, and analyze data based on: 1) a new breed of software tools in which semantic provenance is automatically created and used by the system, 2) the use of open standards based on RDF and Linked Data Principles to facilitate sharing of data and provenance annotations, 3) the use of workflows to represent explicitly all data preparation, integration, and processing steps in a way that is automatically repeatable. Aquatic ecosystems workflow exemplars are provided and discussed in terms of their potential broaden data sharing, analysis and synthesis thereby increasing the impact of aquatic ecosystem research.

  13. Development of scientific tools for monitoring the health of aquatic ecosystems

    NASA Astrophysics Data System (ADS)

    Caldararu, Aurelia; Voiculescu, Mirela; Georgescu, Lucian P.

    2010-05-01

    Humanity is faced nowadays with the major problem of water availability and quality which is a conseqquence of growing demand for water as well as the decline of water quality and quantity. It is not an exaggeration to claim that, without effective management of aquatic ecosystems, the future social and economic development of the world will suffer serious constraints or will be placed significantly at risk. Taking into consideration the fact that the world is rapidly changing, current practices of water management must also change. Developed and developing countries will have to adopt the most effective policies for the management of aquatic ecosystems. They will also have to start using the best techniques for water monitoring. The nature of future problems that could arise in aquatic ecosystems must be carefully anticipated and then objectively analysed in the light of the expected changes. The Water Framework Directive (WFD) requires a holistic knowledge of abiotic and biotic structure and processes that determine the functioning of aquatic ecosystems. Ecological indicators are provided to monitor the ecosystem responses to anthropogenic pressures. We will summarize in this presentation ecological indices that can be used for effective and accurate monitoring of aquatic ecosystems. Different contexts where these indices can be used for environmental health monitoring will be also analysed.

  14. A source of terrestrial organic carbon to investigate the browning of aquatic ecosystems.

    PubMed

    Lennon, Jay T; Hamilton, Stephen K; Muscarella, Mario E; Grandy, A Stuart; Wickings, Kyle; Jones, Stuart E

    2013-01-01

    There is growing evidence that terrestrial ecosystems are exporting more dissolved organic carbon (DOC) to aquatic ecosystems than they did just a few decades ago. This "browning" phenomenon will alter the chemistry, physics, and biology of inland water bodies in complex and difficult-to-predict ways. Experiments provide an opportunity to elucidate how browning will affect the stability and functioning of aquatic ecosystems. However, it is challenging to obtain sources of DOC that can be used for manipulations at ecologically relevant scales. In this study, we evaluated a commercially available source of humic substances ("Super Hume") as an analog for natural sources of terrestrial DOC. Based on chemical characterizations, comparative surveys, and whole-ecosystem manipulations, we found that the physical and chemical properties of Super Hume are similar to those of natural DOC in aquatic and terrestrial ecosystems. For example, Super Hume attenuated solar radiation in ways that will not only influence the physiology of aquatic taxa but also the metabolism of entire ecosystems. Based on its chemical properties (high lignin content, high quinone content, and low C:N and C:P ratios), Super Hume is a fairly recalcitrant, low-quality resource for aquatic consumers. Nevertheless, we demonstrate that Super Hume can subsidize aquatic food webs through 1) the uptake of dissolved organic constituents by microorganisms, and 2) the consumption of particulate fractions by larger organisms (i.e., Daphnia). After discussing some of the caveats of Super Hume, we conclude that commercial sources of humic substances can be used to help address pressing ecological questions concerning the increased export of terrestrial DOC to aquatic ecosystems. PMID:24124511

  15. A Source of Terrestrial Organic Carbon to Investigate the Browning of Aquatic Ecosystems

    PubMed Central

    Lennon, Jay T.; Hamilton, Stephen K.; Muscarella, Mario E.; Grandy, A. Stuart; Wickings, Kyle; Jones, Stuart E.

    2013-01-01

    There is growing evidence that terrestrial ecosystems are exporting more dissolved organic carbon (DOC) to aquatic ecosystems than they did just a few decades ago. This “browning” phenomenon will alter the chemistry, physics, and biology of inland water bodies in complex and difficult-to-predict ways. Experiments provide an opportunity to elucidate how browning will affect the stability and functioning of aquatic ecosystems. However, it is challenging to obtain sources of DOC that can be used for manipulations at ecologically relevant scales. In this study, we evaluated a commercially available source of humic substances (“Super Hume”) as an analog for natural sources of terrestrial DOC. Based on chemical characterizations, comparative surveys, and whole-ecosystem manipulations, we found that the physical and chemical properties of Super Hume are similar to those of natural DOC in aquatic and terrestrial ecosystems. For example, Super Hume attenuated solar radiation in ways that will not only influence the physiology of aquatic taxa but also the metabolism of entire ecosystems. Based on its chemical properties (high lignin content, high quinone content, and low C:N and C:P ratios), Super Hume is a fairly recalcitrant, low-quality resource for aquatic consumers. Nevertheless, we demonstrate that Super Hume can subsidize aquatic food webs through 1) the uptake of dissolved organic constituents by microorganisms, and 2) the consumption of particulate fractions by larger organisms (i.e., Daphnia). After discussing some of the caveats of Super Hume, we conclude that commercial sources of humic substances can be used to help address pressing ecological questions concerning the increased export of terrestrial DOC to aquatic ecosystems. PMID:24124511

  16. NON-TRADITIONAL RESPONSES TO PHARMACEUTICALS IN AQUATIC ECOSYSTEMS

    EPA Science Inventory

    Quantitation of human and veterinary pharmaceuticals in environmental matrices has resulted in pharmaceuticals in the environment receiving unprecedented attention from the scientific community. Aquatic hazard assessments often use quantitative structure activity relationships an...

  17. Ecohydrology of adjacent sagebrush and lodgepole pine ecosystems: the consequences of climate change and disturbance

    USGS Publications Warehouse

    Bradford, John B.; Schlaepfer, Daniel R.; Lauenroth, William K.

    2014-01-01

    Sagebrush steppe and lodgepole pine forests are two of the most widespread vegetation types in the western United States and they play crucial roles in the hydrologic cycle of these water-limited regions. We used a process-based ecosystem water model to characterize the potential impact of climate change and disturbance (wildfire and beetle mortality) on water cycling in adjacent sagebrush and lodgepole pine ecosystems. Despite similar climatic and topographic conditions between these ecosystems at the sites examined, lodgepole pine, and sagebrush exhibited consistent differences in water balance, notably more evaporation and drier summer soils in the sagebrush and greater transpiration and less water yield in lodgepole pine. Canopy disturbances (either fire or beetle) have dramatic impacts on water balance and availability: reducing transpiration while increasing evaporation and water yield. Results suggest that climate change may reduce snowpack, increase evaporation and transpiration, and lengthen the duration of dry soil conditions in the summer, but may have uncertain effects on drainage. Changes in the distribution of sagebrush and lodgepole pine ecosystems as a consequence of climate change and/or altered disturbance regimes will likely alter ecosystem water balance.

  18. Effects of selenium supplementation in cattle on aquatic ecosystems in northern California

    SciTech Connect

    Norman, B.; Nader, G.; Oliver, M.; Delmas, R.; Drake, D.; George, H. )

    1992-09-15

    The potential impact on aquatic ecosystems of supplementing the diets of beef cattle with selenium (Se) was studied on 4 northern California ranches. All study sites included an area of concentrated use by cattle that had diets supplemented with Se. In each case, a stream flowed through the site and provided a control sampling area upstream and a treated sampling area downstream. Specimens of water, sediment, algae, aquatic plants, aquatic invertebrates, and fish were analyzed fluorometrically for total Se content. Significant differences in Se concentration were not found between specimens from upstream control areas and those from downstream areas subjected to use by Se-treated cattle. Evidence was not found that Se supplementation in cattle at maximal permitted concentrations caused Se accumulation in associated aquatic ecosystems.

  19. Technology-Supported Inquiry for Learning about Aquatic Ecosystems

    ERIC Educational Resources Information Center

    Hmelo-Silver, Cindy E.; Eberbach, Catherine; Jordan, Rebecca

    2014-01-01

    Understanding ecosystems is challenging, but important for becoming environmentally-literate citizens of today's society. People have difficulty considering how different components, mechanisms, and phenomena, both visible and invisible, are interconnected within ecosystems. This research presents both the design and initial testing of an…

  20. Agrochemical mitigation of three aquatic macrophytes: implications for ecosystem services

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agricultural runoff containing nitrogen and phosphorus is a major contributor to eutrophication in aquatic systems. Vegetated drainage ditches lining agricultural fields have been investigated for their potential to mitigate runoff, acting similarly to a wetland as they filter contaminants. The ef...

  1. Linking Aquatic Ecosystems to Human Well-Being

    EPA Science Inventory

    While ecological indicators should have relevance to people, a clear methodology to develop and evaluate this characteristic of ecological indicators is not well developed. Economists developed the concept of “Final Ecosystem Goods and Services”. Because these featur...

  2. ACID PRECIPITATION AND ITS EFFECTS ON TERRESTRIAL AND AQUATIC ECOSYSTEMS

    EPA Science Inventory

    Man-induced change in the chemical climate of the earth has increased. Recent research has demonstrated that atmospheric deposition contains both beneficial nutrients and injurious substances; plants, animals, and ecosystems vary greatly in susceptibility; injury is most likely w...

  3. Preventing, controlling, and managing alien species introduction for the health of aquatic and marine ecosystems

    USGS Publications Warehouse

    Short, C.I.; Gross, S.K.; Wilkinson, D.

    2004-01-01

    The introduction and spread of invasive species is an emerging global problem. As economic and ecological impacts continue to grow, there will be an increasing need to develop innovative solutions and global partnerships to combat the increasing rate of invasions and their accompanying impacts. Threats to sustainable fisheries in North America associated with alien species come from many global directions and sources and can be deliberate or the unintended consequence of other actions. Decisions about the role of sustainable fisheries in protecting and restoring the health of aquatic ecosystems become even more complex when economic and social factors are considered along with environmental impacts, because many intentionally introduced species also have associated economic and community costs and benefits. Actions designed to prevent or control alien species in an aquatic ecosystem are often complicated by these nonenvironmental factors as well as public perception and opinion. Aquatic ecosystems are disturbed to varying degrees by alien species, including disease organisms. Prevention is the first and best line of defense. Determining likely pathways and effective countermeasures is more cost-effective than either eradication or control. Our ability to quickly identify new species and their associated risk to ecosystems is critical in designing and implementing effective control and management actions. Lack of infrastructure and necessary resources, clear-cut authority for regulation and action, and scientific information about the biology of alien species and effective control techniques are often limiting factors that prevent the needed action to protect aquatic ecosystems.

  4. Investigating aquatic ecosystems of small lakes in Khorezm, Uzbekistan

    USGS Publications Warehouse

    Saito, L.; Scott, J.; Rosen, M.; Nishonov, Bakhriddin; Chandra, S.; Lamers, John P.A.; Fayzieva, Dilorom; Shanafield, M.

    2009-01-01

    The Khorezm province of Uzbekistan, located in the Aral Sea Basin, suffers from severe environmental and human health problems due to decades of unsustainable land and water management. Agriculture is the dominant land use in Khorezm, and agricultural runoff water has impacted many small lakes. In this water-scarce region, these lakes may provide a water source for irrigation or fish production. Samples have been collected from 13 of these lakes since 2006 to assess water quality, the aquatic food web, and possible limits to aquatic production. Lake salinity varied from 1 to >10 g/L both between and within lakes. Although hydrophobic contaminants concentrations were low (82-241 pg toxic equivalents/mL in June 2006, October 2006, and June 2007), aquatic species diversity and relative density were low in most lakes. Ongoing work is focused on 4 lakes with pelagic food webs to estimate fish production and assess anthropogenic impacts on the food web. Lake sediment cores are also being examined for organic contaminants, and hydrology is being assessed with stable isotopes. ?? 2009 ASCE.

  5. Using Remotely Sensed Data and Hydrologic Models to Evaluate the Effects of Climate Change on Shallow Aquatic Ecosystems in the Mobile Bay, AL Estuary

    NASA Technical Reports Server (NTRS)

    Estes, M. G.; Al-Hamdan, M. Z.; Thom, R.; Judd, C.; Woodruff, D.; Ellis, J. T.; Quattrochi, D.; Swann, R.

    2012-01-01

    Coastal systems in the northern Gulf of Mexico, including the Mobile Bay, AL estuary, are subject to increasing pressure from a variety of activities including climate change. Climate changes have a direct effect on the discharge of rivers that drain into Mobile Bay and adjacent coastal water bodies. The outflows change water quality (temperature, salinity, and sediment concentrations) in the shallow aquatic areas and affect ecosystem functioning. Mobile Bay is a vital ecosystem that provides habitat for many species of fauna and flora. Historically, submerged aquatic vegetation (SAV) and seagrasses were found in this area of the northern Gulf of Mexico; however the extent of vegetation has significantly decreased over the last 60 years. The objectives of this research are to determine: how climate changes affect runoff and water quality in the estuary and how these changes will affect habitat suitability for SAV and seagrasses. Our approach is to use watershed and hydrodynamic modeling to evaluate the impact of climate change on shallow water aquatic ecosystems in Mobile Bay and adjacent coastal areas. Remotely sensed Landsat data were used for current land cover land use (LCLU) model input and the data provided by Intergovernmental Panel on Climate Change (IPCC) of the future changes in temperature, precipitation, and sea level rise were used to create the climate scenarios for the 2025 and 2050 model simulations. Project results are being shared with Gulf coast stakeholders through the Gulf of Mexico Data Atlas to benefit coastal policy and climate change adaptation strategies.

  6. Fire and aquatic ecosystems in forested biomes of North America

    USGS Publications Warehouse

    Gresswell, Robert E.

    1999-01-01

    Synthesis of the literature suggests that physical, chemical, and biological elements of a watershed interact with long-term climate to influence fire regime, and that these factors, in concordance with the postfire vegetation mosaic, combine with local-scale weather to govern the trajectory and magnitude of change following a fire event. Perturbation associated with hydrological processes is probably the primary factor influencing postfire persistence of fishes, benthic macroinvertebrates, and diatoms in fluvial systems. It is apparent that salmonids have evolved strategies to survive perturbations occurring at the frequency of wildland fires (100a??102 years), but local populations of a species may be more ephemeral. Habitat alteration probably has the greatest impact on individual organisms and local populations that are the least mobile, and reinvasion will be most rapid by aquatic organisms with high mobility. It is becoming increasingly apparent that during the past century fire suppression has altered fire regimes in some vegetation types, and consequently, the probability of large stand-replacing fires has increased in those areas. Current evidence suggests, however, that even in the case of extensive high-severity fires, local extirpation of fishes is patchy, and recolonization is rapid. Lasting detrimental effects on fish populations have been limited to areas where native populations have declined and become increasingly isolated because of anthropogenic activities. A strategy of protecting robust aquatic communities and restoring aquatic habitat structure and life history complexity in degraded areas may be the most effective means for insuring the persistence of native biota where the probability of large-scale fires has increased.

  7. Toxic metals in aquatic ecosystems: a microbiological perspective.

    PubMed Central

    Ford, T; Ryan, D

    1995-01-01

    Microbe-metal interactions in aquatic environments and their exact role in transport and transformations of toxic metals are poorly understood. This paper will briefly review our understanding of these interactions. Ongoing research in Lake Chapala, Mexico, the major water source for the City of Guadalajara, provides an opportunity to study the microbiological aspects of metal-cycling in the water column. Constant resuspension of sediments provides a microbiologically rich aggregate-based system. Data indicate that toxic metals are concentrated on aggregate material and bioaccumulate in the food chain. A provisional model is presented for involvement of microbial aggregates in metal-cycling in Lake Chapala. PMID:7621793

  8. Toxic metals in aquatic ecosystems: a microbiological perspective.

    PubMed

    Ford, T; Ryan, D

    1995-02-01

    Microbe-metal interactions in aquatic environments and their exact role in transport and transformations of toxic metals are poorly understood. This paper will briefly review our understanding of these interactions. Ongoing research in Lake Chapala, Mexico, the major water source for the City of Guadalajara, provides an opportunity to study the microbiological aspects of metal-cycling in the water column. Constant resuspension of sediments provides a microbiologically rich aggregate-based system. Data indicate that toxic metals are concentrated on aggregate material and bioaccumulate in the food chain. A provisional model is presented for involvement of microbial aggregates in metal-cycling in Lake Chapala. PMID:7621793

  9. Challenges of deriving a complete biosphere greenhouse gas balance through integration of terrestrial and aquatic ecosystems

    NASA Astrophysics Data System (ADS)

    Peichl, Matthias

    2013-04-01

    Past research efforts have mostly focused on separately investigating the exchange of greenhouse gases (GHGs) within the limits of different terrestrial and aquatic ecosystem types. More recently however, it has been recognized that GHG exchanges and budgets are not limited to boundaries of the terrestrial or aquatic biosphere components and instead are often tightly linked amongst the different ecosystem types. Primarily the aquatic production and export of GHGs due to substrate supply or discharge from surrounding terrestrial ecosystems play a major role in regional GHG budgets. Understanding the mechanisms and drivers of this connectivity between different terrestrial and aquatic ecosystem GHG exchanges is therefore necessary to develop landscape-level GHG budgets and to understand their sensitivity to disturbances of the biosphere. Moreover, the exchange of carbon dioxide (CO2) as the most important GHG species has been the primary research objective with regards to obtaining better estimates of the carbon sequestration potential of the biosphere. However, methane (CH4) and nitrous oxide (N2O) emissions may offset CO2 sinks and considerably affect the complete GHG balance in both terrestrial and aquatic systems. Including their contribution and improved knowledge on the dynamics of these two gas species is therefore essential for complete GHG budget estimates. At present, the integration of terrestrial and aquatic GHG exchanges toward landscape GHG budgets poses numerous challenges. These include the need for a better knowledge of i) the contribution of CH4 and N2O to the GHG budgets within contrasting terrestrial (forests, peatlands, grasslands, croplands) and aquatic (lake, streams) ecosystems when integrated over a full year, ii) the effect of ecosystem properties (e.g. age and/or development stage, size of water body) on the GHG balance, iii) the impact of management effects (e.g. nitrogen fertilizer application), iv) differences among climate regions and v

  10. EFFECTS OF CHLORENDIC ACID, A PRIORITY TOXIC SUBSTANCES, ON LABORATORY AQUATIC ECOSYSTEMS

    EPA Science Inventory

    Experiments were conducted to estimate the effects of chlorendic acid and its neutralized form on laboratory aquatic ecosystems. In short-term flask studies, chlorendic acid concentrations of 500 mg/L (pH 3.5) completely inhibited algal growth and microfaunal activity, 250 mg/L (...

  11. Fuzzy model for risk assessment of persistent organic pollutants in aquatic ecosystems.

    PubMed

    Seguí, X; Pujolasus, E; Betrò, S; Agueda, A; Casal, J; Ocampo-Duque, W; Rudolph, I; Barra, R; Páez, M; Barón, E; Eljarrat, E; Barceló, D; Darbra, R M

    2013-07-01

    We developed a model for evaluating the environmental risk of persistent organic pollutants (POPs) to aquatic organisms. The model is based on fuzzy theory and uses information provided by international experts through a questionnaire. It has been tested in two case studies for a particular type of POPs: brominated flame retardants (BFRs). The first case study is related to the EU-funded AQUATERRA project, with sampling campaigns carried out in two Ebro tributaries in Spain (the Cinca and Vero Rivers). The second one, named the BROMACUA project, assessed different aquatic ecosystems in Chile (San Vicente Bay) and Colombia (Santa Marta Marsh). In both projects, the BFRs under study were polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD). However, the model can be extrapolated to other POPs and to different aquatic ecosystems to provide useful results for decision-makers. PMID:23524177

  12. ECOSYSTEM RESTORATION: MANAGEMENT PRACTICES FOR PROTECTING AND ENHANCING AQUATIC RESOURCES

    EPA Science Inventory

    This poster describes research that addresses the question: Which management practices are most successful for protection and restoration of ecological resources? The Ecosystem Restoration Research Program of EPA/ORD is designed to conduct basic and applied field research to eva...

  13. Palladium Nanoparticles: Is There a Risk for Aquatic Ecosystems?

    PubMed

    Lüderwald, Simon; Seitz, Frank; Seisenbaeva, Gulaim A; Kessler, Vadim G; Schulz, Ralf; Bundschuh, Mirco

    2016-08-01

    Nano-sized palladium (nano-Pd) is used in catalytic converters of automobiles, where it can be released into the environment by abrasion. Although these particles may subsequently be transported into surface water bodies, no data estimating their fate and toxicity in aquatic systems exists. This study characterized the particle size development of nano-Pd (advertised size ~12 nm; hydrodynamic size ~70 nm) in media with variable ionic strength (IS). Additionally, the particles' acute toxicity for daphnids and chironomids was assessed. While nano-Pd agglomerated more quickly with increasing IS, it caused only marginal effects in both test species after 96 h of exposure. After 144 h of exposure, however, an EC50 value of 1.23 mg nano-Pd/L for daphnids was determined indicating effects over the long run. When considering the relatively low environmental concentration of elemental Pd in surface waters (usually ng/L), though, this study suggests only a low aquatic risk in response to nano-Pd. PMID:27107586

  14. Aquatic polymers can drive pathogen transmission in coastal ecosystems

    PubMed Central

    Shapiro, Karen; Krusor, Colin; Mazzillo, Fernanda F. M.; Conrad, Patricia A.; Largier, John L.; Mazet, Jonna A. K.; Silver, Mary W.

    2014-01-01

    Gelatinous polymers including extracellular polymeric substances (EPSs) are fundamental to biophysical processes in aquatic habitats, including mediating aggregation processes and functioning as the matrix of biofilms. Yet insight into the impact of these sticky molecules on the environmental transmission of pathogens in the ocean is limited. We used the zoonotic parasite Toxoplasma gondii as a model to evaluate polymer-mediated mechanisms that promote transmission of terrestrially derived pathogens to marine fauna and humans. We show that transparent exopolymer particles, a particulate form of EPS, enhance T. gondii association with marine aggregates, material consumed by organisms otherwise unable to access micrometre-sized particles. Adhesion to EPS biofilms on macroalgae also captures T. gondii from the water, enabling uptake of pathogens by invertebrates that feed on kelp surfaces. We demonstrate the acquisition, concentration and retention of T. gondii by kelp-grazing snails, which can transmit T. gondii to threatened California sea otters. Results highlight novel mechanisms whereby aquatic polymers facilitate incorporation of pathogens into food webs via association with particle aggregates and biofilms. Identifying the critical role of invisible polymers in transmission of pathogens in the ocean represents a fundamental advance in understanding and mitigating the health impacts of coastal habitat pollution with contaminated runoff. PMID:25297861

  15. Aquatic polymers can drive pathogen transmission in coastal ecosystems.

    PubMed

    Shapiro, Karen; Krusor, Colin; Mazzillo, Fernanda F M; Conrad, Patricia A; Largier, John L; Mazet, Jonna A K; Silver, Mary W

    2014-11-22

    Gelatinous polymers including extracellular polymeric substances (EPSs) are fundamental to biophysical processes in aquatic habitats, including mediating aggregation processes and functioning as the matrix of biofilms. Yet insight into the impact of these sticky molecules on the environmental transmission of pathogens in the ocean is limited. We used the zoonotic parasite Toxoplasma gondii as a model to evaluate polymer-mediated mechanisms that promote transmission of terrestrially derived pathogens to marine fauna and humans. We show that transparent exopolymer particles, a particulate form of EPS, enhance T. gondii association with marine aggregates, material consumed by organisms otherwise unable to access micrometre-sized particles. Adhesion to EPS biofilms on macroalgae also captures T. gondii from the water, enabling uptake of pathogens by invertebrates that feed on kelp surfaces. We demonstrate the acquisition, concentration and retention of T. gondii by kelp-grazing snails, which can transmit T. gondii to threatened California sea otters. Results highlight novel mechanisms whereby aquatic polymers facilitate incorporation of pathogens into food webs via association with particle aggregates and biofilms. Identifying the critical role of invisible polymers in transmission of pathogens in the ocean represents a fundamental advance in understanding and mitigating the health impacts of coastal habitat pollution with contaminated runoff. PMID:25297861

  16. Potential Effects of Climate Change on Aquatic Ecosystems of the Great Plains of North America

    NASA Astrophysics Data System (ADS)

    Covich, A. P.; Fritz, S. C.; Lamb, P. J.; Marzolf, R. D.; Matthews, W. J.; Poiani, K. A.; Prepas, E. E.; Richman, M. B.; Winter, T. C.

    1997-06-01

    The Great Plains landscape is less topographically complex than most other regions within North America, but diverse aquatic ecosystems, such as playas, pothole lakes, ox-bow lakes, springs, groundwater aquifers, intermittent and ephemeral streams, as well as large rivers and wetlands, are highly dynamic and responsive to extreme climatic fluctuations. We review the evidence for climatic change that demonstrates the historical importance of extremes in north-south differences in summer temperatures and east-west differences in aridity across four large subregions. These physical driving forces alter density stratification, deoxygenation, decomposition and salinity. Biotic community composition and associated ecosystem processes of productivity and nutrient cycling respond rapidly to these climatically driven dynamics. Ecosystem processes also respond to cultural effects such as dams and diversions of water for irrigation, waste dilution and urban demands for drinking water and industrial uses. Distinguishing climatic from cultural effects in future models of aquatic ecosystem functioning will require more refinement in both climatic and economic forecasting. There is a need, for example, to predict how long-term climatic forecasts (based on both ENSO and global warming simulations) relate to the permanence and productivity of shallow water ecosystems. Aquatic ecologists, hydrologists, climatologists and geographers have much to discuss regarding the synthesis of available data and the design of future interdisciplinary research.

  17. Potential effects of climate change on aquatic ecosystems of the Great Plains of North America

    USGS Publications Warehouse

    Covich, A.P.; Fritz, S.C.; Lamb, P.J.; Marzolf, R.D.; Matthews, W.J.; Poiani, K.A.; Prepas, E.E.; Richman, M.B.; Winter, T.C.

    1997-01-01

    The Great Plains landscape is less topographically complex than most other regions within North America, but diverse aquatic ecosystems, such as playas, pothole lakes, ox-bow lakes, springs, groundwater aquifers, intermittent and ephemeral streams, as well as large rivers and wetlands, are highly dynamic and responsive to extreme climatic fluctuations. We review the evidence for climatic change that demonstrates the historical importance of extremes in north-south differences in summer temperatures and east-west differences in aridity across four large subregions. These physical driving forces alter density stratification, deoxygenation, decomposition and salinity. Biotic community composition and associated ecosystem processes of productivity and nutrient cycling respond rapidly to these climatically driven dynamics. Ecosystem processes also respond to cultural effects such as dams and diversions of water for irrigation, waste dilution and urban demands for drinking water and industrial uses. Distinguishing climatic from cultural effects in future models of aquatic ecosystem functioning will require more refinement in both climatic and economic forecasting. There is a need, for example, to predict how long-term climatic forecasts (based on both ENSO and global warming simulations) relate to the permanence and productivity of shallow water ecosystems. Aquatic ecologists, hydrologists, climatologists and geographers have much to discuss regarding the synthesis of available data and the design of future interdisciplinary research. ?? 1997 by John Wiley & Sons, Ltd.

  18. Aquatic risk assessment of herbicides in freshwater ecosystems of South Florida.

    PubMed

    Schuler, Lance J; Rand, Gary M

    2008-05-01

    Widespread, high-volume use and subsequent off-site transport of herbicides, specifically photosystem II inhibitors (PSII), on agricultural and noncultivated lands in south Florida has resulted in frequent detections in freshwater systems. In light of the current restoration efforts as part of the Comprehensive Environmental Restoration Plan (CERP), increased water flows containing detectable herbicide levels into the Everglades ecosystem and adjacent areas may have adverse consequences to the unique plant communities present in the region. The potential impact of individual herbicides to aquatic plant and algae species was examined using a probabilistic risk assessment approach. Risk was characterized for nine PSII herbicides (four triazines: ametryn, atrazine, simazine, and prometryn; two triazinones: hexazinone and metribuzin; two substituted ureas: diuron and linuron; and a uracil: bromacil) and a pyridazinone herbicide (norflurazon) by comparing the overlap of the 90th percentile surface water concentration (exposure benchmark) from the exposure distributions to the 10th percentile of effects (effects benchmark) determined from species sensitivity distributions of acute laboratory toxicity data. Overall, the risk of the individual herbicides was generally low. A Multiple Substance Potentially Affected Fraction (msPAF) risk approach also was utilized to examine the joint toxicity of the herbicide mixtures based on a concentration addition model. The risk associated with the herbicide mixture (mainly bromacil, diuron, and norflurazon) was determined to be high for Lee (site S79 on the Caloosahatchee River), Martin (site S80 on St. Lucie Canal), and St. Lucie (site S99 on C25 emptying into Indian River Lagoon) counties in south Florida. This study highlights the need to consider joint action of chemical mixtures as part of an ecological risk assessment. PMID:18094912

  19. The influence of glacial meltwater on alpine aquatic ecosystems: a review.

    PubMed

    Slemmons, Krista E H; Saros, Jasmine E; Simon, Kevin

    2013-10-01

    The recent and rapid recession of alpine glaciers over the last 150 years has major implications for associated aquatic communities. Glacial meltwater shapes many of the physical features of high altitude lakes and streams, producing turbid environments with distinctive hydrology patterns relative to nival systems. Over the past decade, numerous studies have investigated the chemical and biological effects of glacial meltwater on freshwater ecosystems. Here, we review these studies across both lake and stream ecosystems. Focusing on alpine regions mainly in the Northern Hemisphere, we present examples of how glacial meltwater can affect habitat by altering physical and chemical features of aquatic ecosystems, and review the subsequent effects on the biological structure and function of lakes and streams. Collectively or separately, these factors can drive the overall distribution, diversity and behavior of primary producers, triggering cascading effects throughout the food web. We conclude by proposing areas for future research, particularly in regions where glaciers are soon projected to disappear. PMID:24056713

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

  1. Effects of solar UV radiation on aquatic ecosystems and interactions with climate change.

    PubMed

    Häder, D-P; Kumar, H D; Smith, R C; Worrest, R C

    2007-03-01

    Recent results continue to show the general consensus that ozone-related increases in UV-B radiation can negatively influence many aquatic species and aquatic ecosystems (e.g., lakes, rivers, marshes, oceans). Solar UV radiation penetrates to ecological significant depths in aquatic systems and can affect both marine and freshwater systems from major biomass producers (phytoplankton) to consumers (e.g., zooplankton, fish, etc.) higher in the food web. Many factors influence the depth of penetration of radiation into natural waters including dissolved organic compounds whose concentration and chemical composition are likely to be influenced by future climate and UV radiation variability. There is also considerable evidence that aquatic species utilize many mechanisms for photoprotection against excessive radiation. Often, these protective mechanisms pose conflicting selection pressures on species making UV radiation an additional stressor on the organism. It is at the ecosystem level where assessments of anthropogenic climate change and UV-related effects are interrelated and where much recent research has been directed. Several studies suggest that the influence of UV-B at the ecosystem level may be more pronounced on community and trophic level structure, and hence on subsequent biogeochemical cycles, than on biomass levels per se. PMID:17344962

  2. Impact of petroleum pollution on aquatic coastal ecosystems in Brazil

    SciTech Connect

    Silva, E.M. da; Peso-Aguiar, M.C.; Navarro, M.F.T.; Chastinet, C.B.A.

    1997-01-01

    Although oil activities generate numerous forms of environmental impact on biological communities, studies of these impacts on Brazilian coastal ecosystems are rate. Results of tests for the content of oil in sediments and organisms indicate a substantially high rate of degradation. Results for uptake of polycyclic aromatic hydrocarbons in bivalves suggested the recent occurrence of oil spills and that these organisms differed in their capabilities to bioconcentrate oil. The mangrove community has suffered constant inputs of oil and has responded with increased numbers of aerial roots, generation of malformed leaves and fruits by plants, and a decrease in litter production. Studies of the impact of oil on rocky shore communities and the toxicity of oil and its by-products to marine organisms have confirmed the results reported in the literature. Presently most of the available studies deal with the macroscopic effects of oil on organisms and have indicated that the nature of oil, climate characteristics, the physical environment, and the structure of the community influence the symptoms of oil contamination in organisms of coastal waters. Long-term studies should be carried out to assess changes in community structure, sublethal effects in populations, and the resilience of contaminated ecosystems.

  3. Phylogenetic signal in diatom ecology: perspectives for aquatic ecosystems biomonitoring.

    PubMed

    Keck, François; Rimet, Frédéric; Franc, Alain; Bouchez, Agnés

    2016-04-01

    Diatoms include a great diversity of taxa and are recognized as powerful bioindicators in rivers. However using diatoms for monitoring programs is costly and time consuming because most of the methodologies necessitate species-level identification. This raises the question of the optimal trade-off between taxonomic resolution and bioassessment quality. Phylogenetic tools may form the bases of new, more efficient approaches for biomonitoring if relationships between ecology and phylogeny can be demonstrated. We estimated the ecological optima of 127 diatom species for 19 environmental parameters using count data from 2119 diatom communities sampled during eight years in eastern France. Using uni- and multivariate analyses, we explored the relationships between freshwater diatom phylogeny and ecology (i.e., the phylogenetic signal). We found a significant phylogenetic signal for many of the ecological optima that were tested, but the strength of the signal varied significantly from one trait to another. Multivariate analysis also showed that the multidimensional ecological niche of diatoms can be strongly related to phylogeny. The presence of clades containing species that exhibit homogeneous ecology suggests that phylogenetic information can be useful for aquatic biomonitoring. This study highlights the presence of significant patterns of ecological optima for freshwater diatoms in relation to their phylogeny. These results suggest the presence of a signal above the species level, which is encouraging for the development of simplified methods for biomonitoring survey. PMID:27411256

  4. Modeling an aquatic ecosystem: application of an evolutionary algorithm with genetic doping to reduce prediction uncertainty

    NASA Astrophysics Data System (ADS)

    Friedel, Michael; Buscema, Massimo

    2016-04-01

    Aquatic ecosystem models can potentially be used to understand the influence of stresses on catchment resource quality. Given that catchment responses are functions of natural and anthropogenic stresses reflected in sparse and spatiotemporal biological, physical, and chemical measurements, an ecosystem is difficult to model using statistical or numerical methods. We propose an artificial adaptive systems approach to model ecosystems. First, an unsupervised machine-learning (ML) network is trained using the set of available sparse and disparate data variables. Second, an evolutionary algorithm with genetic doping is applied to reduce the number of ecosystem variables to an optimal set. Third, the optimal set of ecosystem variables is used to retrain the ML network. Fourth, a stochastic cross-validation approach is applied to quantify and compare the nonlinear uncertainty in selected predictions of the original and reduced models. Results are presented for aquatic ecosystems (tens of thousands of square kilometers) undergoing landscape change in the USA: Upper Illinois River Basin and Central Colorado Assessment Project Area, and Southland region, NZ.

  5. Carbon and nitrogen isotope studies in an arctic aquatic ecosystem

    SciTech Connect

    Schell, D.M.

    1989-01-01

    The Phase II studies of the R4D Program on stream and watershed ecology reflect the accomplishments and accumulation of baseline information obtained during the past studies. Although our rough estimates indicate that nitrogen inputs to the watershed ba lance losses, the carbon fluxes suggest that they are not in equilibrium and that there is a net loss of carbon from the tundra ecosystem through respiration and transport out of the watershed via the stream system. Radiocarbon profiles of soil sections coupled with mass transport calculations revealed that peat accumulation has essentially ceased in the R4D watershed and appears to be in ablative loss. Thus the carbon flux measurements provide validation tests for the PLANTGRO and GAS-HYDRO models of the PHASE II studies. These findings are also important in the context of global CO[sub 2] increases from positive feedback mechanisms in peatlands associated with climatic warming in the subarctic regions.

  6. Carbon and nitrogen isotope studies in an arctic aquatic ecosystem

    SciTech Connect

    Schell, D.M.

    1989-12-31

    The Phase II studies of the R4D Program on stream and watershed ecology reflect the accomplishments and accumulation of baseline information obtained during the past studies. Although our rough estimates indicate that nitrogen inputs to the watershed ba lance losses, the carbon fluxes suggest that they are not in equilibrium and that there is a net loss of carbon from the tundra ecosystem through respiration and transport out of the watershed via the stream system. Radiocarbon profiles of soil sections coupled with mass transport calculations revealed that peat accumulation has essentially ceased in the R4D watershed and appears to be in ablative loss. Thus the carbon flux measurements provide validation tests for the PLANTGRO and GAS-HYDRO models of the PHASE II studies. These findings are also important in the context of global CO{sub 2} increases from positive feedback mechanisms in peatlands associated with climatic warming in the subarctic regions.

  7. Heavy Metal Pollution Characteristics of Surface Sediments in Different Aquatic Ecosystems in Eastern China: A Comprehensive Understanding

    PubMed Central

    Tang, Wenzhong; Shan, Baoqing; Zhang, Wenqiang; Zhang, Hong; Wang, Lishuo; Ding, Yuekui

    2014-01-01

    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. PMID:25268385

  8. Diversity and Expression of Bacterial Metacaspases in an Aquatic Ecosystem

    PubMed Central

    Asplund-Samuelsson, Johannes; Sundh, John; Dupont, Chris L.; Allen, Andrew E.; McCrow, John P.; Celepli, Narin A.; Bergman, Birgitta; Ininbergs, Karolina; Ekman, Martin

    2016-01-01

    Metacaspases are distant homologs of metazoan caspase proteases, implicated in stress response, and programmed cell death (PCD) in bacteria and phytoplankton. While the few previous studies on metacaspases have relied on cultured organisms and sequenced genomes, no studies have focused on metacaspases in a natural setting. We here present data from the first microbial community-wide metacaspase survey; performed by querying metagenomic and metatranscriptomic datasets from the brackish Baltic Sea, a water body characterized by pronounced environmental gradients and periods of massive cyanobacterial blooms. Metacaspase genes were restricted to ~4% of the bacteria, taxonomically affiliated mainly to Bacteroidetes, Alpha- and Betaproteobacteria and Cyanobacteria. The gene abundance was significantly higher in larger or particle-associated bacteria (>0.8 μm), and filamentous Cyanobacteria dominated metacaspase gene expression throughout the bloom season. Distinct seasonal expression patterns were detected for the three metacaspase genes in Nodularia spumigena, one of the main bloom-formers. Clustering of normalized gene expression in combination with analyses of genomic and assembly data suggest functional diversification of these genes, and possible roles of the metacaspase genes related to stress responses, i.e., sulfur metabolism in connection to oxidative stress, and nutrient stress induced cellular differentiation. Co-expression of genes encoding metacaspases and nodularin toxin synthesis enzymes was also observed in Nodularia spumigena. The study shows that metacaspases represent an adaptation of potentially high importance for several key organisms in the Baltic Sea, most prominently Cyanobacteria, and open up for further exploration of their physiological roles in microbes and assessment of their ecological impact in aquatic habitats. PMID:27458440

  9. Drought sensitivity predicts habitat size sensitivity in an aquatic ecosystem.

    PubMed

    Amundrud, Sarah L; Srivastava, Diane S

    2015-07-01

    Species and trophic richness often increase with habitat size. Although many ecological processes have been evoked to explain both patterns, the environmental stress associated with small habitats has rarely been considered. We propose that larger habitats may be species rich simply because their environmental conditions are within the fundamental niche of more species; larger habitats may also have more trophic levels if traits of predators render them vulnerable to environmental stress. We test this hypothesis using the aquatic insect larvae in water-filled bromeliads. In bromeliads, the probability of desiccation is greatest in small plants. For the 10 most common bromeliad insect taxa, we ask whether differences in drought tolerance and regional abundances between taxa predict community and trophic composition over a gradient of bromeliad size. First, we used bromeliad survey data to calculate the mean habitat size of occurrence of each taxon. Comparing the observed mean habitat size of occurrence to that expected from random species assembly based on differences in their regional abundances allowed us to obtain habitat size sensitivity indices (as Z scores) for the various insect taxa. Second, we obtained drought sensitivity indices by subjecting individual insects to drought and measuring the effects on relative growth rates in a mesocosm experiment. We found that drought sensitivity strongly, predicts habitat size sensitivity in bromeliad insects. However, an increase in trophic richness with habitat size could not be explained by an increased sensitivity of predators to drought, but rather by sampling effects, as predators were rare compared to lower trophic levels. This finding suggests that physiological tolerance to environmental stress can be relevant in explaining the universal increase in species with habitat size. PMID:26378317

  10. Diversity and Expression of Bacterial Metacaspases in an Aquatic Ecosystem.

    PubMed

    Asplund-Samuelsson, Johannes; Sundh, John; Dupont, Chris L; Allen, Andrew E; McCrow, John P; Celepli, Narin A; Bergman, Birgitta; Ininbergs, Karolina; Ekman, Martin

    2016-01-01

    Metacaspases are distant homologs of metazoan caspase proteases, implicated in stress response, and programmed cell death (PCD) in bacteria and phytoplankton. While the few previous studies on metacaspases have relied on cultured organisms and sequenced genomes, no studies have focused on metacaspases in a natural setting. We here present data from the first microbial community-wide metacaspase survey; performed by querying metagenomic and metatranscriptomic datasets from the brackish Baltic Sea, a water body characterized by pronounced environmental gradients and periods of massive cyanobacterial blooms. Metacaspase genes were restricted to ~4% of the bacteria, taxonomically affiliated mainly to Bacteroidetes, Alpha- and Betaproteobacteria and Cyanobacteria. The gene abundance was significantly higher in larger or particle-associated bacteria (>0.8 μm), and filamentous Cyanobacteria dominated metacaspase gene expression throughout the bloom season. Distinct seasonal expression patterns were detected for the three metacaspase genes in Nodularia spumigena, one of the main bloom-formers. Clustering of normalized gene expression in combination with analyses of genomic and assembly data suggest functional diversification of these genes, and possible roles of the metacaspase genes related to stress responses, i.e., sulfur metabolism in connection to oxidative stress, and nutrient stress induced cellular differentiation. Co-expression of genes encoding metacaspases and nodularin toxin synthesis enzymes was also observed in Nodularia spumigena. The study shows that metacaspases represent an adaptation of potentially high importance for several key organisms in the Baltic Sea, most prominently Cyanobacteria, and open up for further exploration of their physiological roles in microbes and assessment of their ecological impact in aquatic habitats. PMID:27458440

  11. Staunton 1 reclamation demonstration project. Aquatic ecosystems. Final report

    SciTech Connect

    Vinikour, W. S.

    1981-02-01

    To provide long-term indications of the potential water quality improvements following reclamation efforts at the Staunton 1 Reclamation Demonstration Project, macroinvertebrates were collected from three on-site ponds and from the receiving stream (Cahokia Creek) for site drainage. Implications for potential benthic community differences resulting from site runoff were disclosed, but macroinvertebrate diversity throughout Cahokia Creek was limited due to an unstable, sandy substrate. The three ponds sampled were the New Pond, which was created as part of the reclamation activities; the Shed Pond, which and the Old Pond, which, because it was an existing, nonimpacted pond free of site runoff, served as a control. Comparisons of macroinvertebrates from the ponds indicated the potential for the New Pond to develop into a productive ecosystem. Macroinvertebrates in the New Pond were generally species more tolerant of acid mine drainage conditions. However, due to the present limited faunal densities and the undesirable physical and chemical characteristics of the New Pond, the pond should not be stocked with fish at this time.

  12. Human effects on ecological connectivity in aquatic ecosystems: Integrating scientific approaches to support management and mitigation.

    PubMed

    Crook, David A; Lowe, Winsor H; Allendorf, Frederick W; Erős, Tibor; Finn, Debra S; Gillanders, Bronwyn M; Hadwen, Wade L; Harrod, Chris; Hermoso, Virgilio; Jennings, Simon; Kilada, Raouf W; Nagelkerken, Ivan; Hansen, Michael M; Page, Timothy J; Riginos, Cynthia; Fry, Brian; Hughes, Jane M

    2015-11-15

    Understanding the drivers and implications of anthropogenic disturbance of ecological connectivity is a key concern for the conservation of biodiversity and ecosystem processes. Here, we review human activities that affect the movements and dispersal of aquatic organisms, including damming of rivers, river regulation, habitat loss and alteration, human-assisted dispersal of organisms and climate change. Using a series of case studies, we show that the insight needed to understand the nature and implications of connectivity, and to underpin conservation and management, is best achieved via data synthesis from multiple analytical approaches. We identify four key knowledge requirements for progressing our understanding of the effects of anthropogenic impacts on ecological connectivity: autecology; population structure; movement characteristics; and environmental tolerance/phenotypic plasticity. Structuring empirical research around these four broad data requirements, and using this information to parameterise appropriate models and develop management approaches, will allow for mitigation of the effects of anthropogenic disturbance on ecological connectivity in aquatic ecosystems. PMID:25917446

  13. ANN application for prediction of atmospheric nitrogen deposition to aquatic ecosystems.

    PubMed

    Palani, Sundarambal; Tkalich, Pavel; Balasubramanian, Rajasekhar; Palanichamy, Jegathambal

    2011-06-01

    The occurrences of increased atmospheric nitrogen deposition (ADN) in Southeast Asia during smoke haze episodes have undesired consequences on receiving aquatic ecosystems. A successful prediction of episodic ADN will allow a quantitative understanding of its possible impacts. In this study, an artificial neural network (ANN) model is used to estimate atmospheric deposition of total nitrogen (TN) and organic nitrogen (ON) concentrations to coastal aquatic ecosystems. The selected model input variables were nitrogen species from atmospheric deposition, Total Suspended Particulates, Pollutant Standards Index and meteorological parameters. ANN models predictions were also compared with multiple linear regression model having the same inputs and output. ANN model performance was found relatively more accurate in its predictions and adequate even for high-concentration events with acceptable minimum error. The developed ANN model can be used as a forecasting tool to complement the current TN and ON analysis within the atmospheric deposition-monitoring program in the region. PMID:21481425

  14. Possible Limiting Nutrient Factor in Long Term Operation of Closed Aquatic Ecosystem

    NASA Astrophysics Data System (ADS)

    Hao, Zongjie; Wang, Gaohong; Liu, Yongding

    A lab mini-module of Closed Aquatic Ecosystem consisting of Chlorella pyrenoidosa and Bulinus australianus was constructed to study the effect of nutrient limitation on long term operation. A series of tests were taken, the first introduced was consumer part Bulinus australianus, the second nutrient introduced was inorganic carbon source, organic carbon source glucose was injected into a third set of the systems, The fourth one is Chlorella pyrenoidosa only, acting as the control.Results showed the one with Bulinus australianus came to a steady state 17 days after closure, and algae in those introduced carbon source grew better than monoculture. It is inferred that nutrient limitation is inevitable in Long term operation of Closed Aquatic Ecosystem, especially carbon which is partly restored as carbon pool is out of element cycle.

  15. Effects of future land use on biogeography of aquatic ecosystems of Amazonia

    NASA Astrophysics Data System (ADS)

    Howard, E. A.; Coe, M. T.; Foley, J. A.; Costa, M. H.

    2006-12-01

    Amazonian ecosystems provide key ecosystem services, such as regulating the amount and timing of water and carbon flows through the Amazon Basin. Land use in these ecosystems affects regional water balance, which in turn affects biogeography of aquatic ecosystems, including wetlands and floodplains. We combined a hydrological model (Terrestrial Hydrology Model with Biogeochemistry, THMB), remote sensing observations (Hess et al. 2003), and empirical data to identify the distribution of aquatic biogeographic types throughout the central Amazon basin over time. We explored how future land-use scenarios for the Amazon Basin through 2030 (Soares-Filho et al. 2004) would modify the spatial and temporal patterns of aquatic ecosystems as compared to a baseline of natural potential vegetation cover under historical climate variability for the 20th century. We calibrated monthly simulation results with remotely sensed observations of flooded area and extent of different wetland categories for high and low water periods over a 1.7 million sq. km region of the central Amazon. Two additional dimensions of floodplain biogeography (river size and color) were added to provide insight into the geographic distribution of key ecosystem types and their flooding seasonality. For historical conditions, the model results reproduced regional differences in seasonal flood extent and timing north and south of the Amazon mainstem, reflecting the dominant climatic regimes. Black-water streams and medium-sized rivers, followed by large white-water rivers, were the most extensive types across the study region. However much of the black water was in areas likely to be influenced by white-water rivers while flooded. The monthly extent of flooded areas dominated by woody vegetation was consistently more strongly seasonal than non-woody areas. Also, the extent of flooding in muddy and semi-muddy rivers and floodplains tended to be more highly seasonal than in black- and clear-water areas. We

  16. Selenium biotransformations in an engineered aquatic ecosystem for bioremediation of agricultural wastewater via brine shrimp production.

    PubMed

    Schmidt, Radomir; Tantoyotai, Prapakorn; Fakra, Sirine C; Marcus, Matthew A; Yang, Soo In; Pickering, Ingrid J; Bañuelos, Gary S; Hristova, Krassimira R; Freeman, John L

    2013-05-21

    An engineered aquatic ecosystem was specifically designed to bioremediate selenium (Se), occurring as oxidized inorganic selenate from hypersalinized agricultural drainage water while producing brine shrimp enriched in organic Se and omega-3 and omega-6 fatty acids for use in value added nutraceutical food supplements. Selenate was successfully bioremediated by microalgal metabolism into organic Se (seleno-amino acids) and partially removed via gaseous volatile Se formation. Furthermore, filter-feeding brine shrimp that accumulated this organic Se were removed by net harvest. Thriving in this engineered pond system, brine shrimp ( Artemia franciscana Kellogg) and brine fly (Ephydridae sp.) have major ecological relevance as important food sources for large populations of waterfowl, breeding, and migratory shore birds. This aquatic ecosystem was an ideal model for study because it mimics trophic interactions in a Se polluted wetland. Inorganic selenate in drainage water was metabolized differently in microalgae, bacteria, and diatoms where it was accumulated and reduced into various inorganic forms (selenite, selenide, or elemental Se) or partially incorporated into organic Se mainly as selenomethionine. Brine shrimp and brine fly larva then bioaccumulated Se from ingesting aquatic microorganisms and further metabolized Se predominately into organic Se forms. Importantly, adult brine flies, which hatched from aquatic larva, bioaccumulated the highest Se concentrations of all organisms tested. PMID:23621086

  17. Time series analysis and the analysis of aquatic and riparian ecosystems

    USGS Publications Warehouse

    Milhous, R.T.

    2003-01-01

    Time series analysis of physical instream habitat and the riparian zone is not done as frequently as would be beneficial in understanding the fisheries aspects of the aquatic ecosystem. This paper presents two case studies have how time series analysis may be accomplished. Time series analysis is the analysis of the variation of the physical habitat or the hydro-period in the riparian zone (in many situations, the floodplain).

  18. K-Pg events facilitated lineage transitions between terrestrial and aquatic ecosystems.

    PubMed

    Procheş, Serban; Polgar, Gianluca; Marshall, David J

    2014-06-01

    We use dated phylogenetic trees for tetrapod vertebrates to identify lineages that shifted between terrestrial and aquatic ecosystems in terms of feeding or development, and to assess the timing of such events. Both stem and crown lineage ages indicate a peak in transition events in correspondence with the K-Pg mass extinction. This meets the prediction that changes in competitive pressure and resource availability following mass extinction events should facilitate such transitions. PMID:24919699

  19. EcoCasting: Using NetLogo models of aquatic ecosystems to teach scientific inquiry

    NASA Astrophysics Data System (ADS)

    Buzby, C. K.; Jona, K.

    2010-12-01

    The EcoCasting project from the Office of STEM Education Partnerships (OSEP) at Northwestern University has developed a computer model-based curriculum for high school environmental science classes to study complexity in aquatic ecosystems. EcoCasting aims to deliver cutting edge scientific research on bioaccumulation in invaded Great Lakes food webs to high school classes. Scientists and environmental engineers at Northwestern are investigating unusual bioaccumulation patterns in invaded food webs of the Great Lakes. High school students are exploring this authentic data to understand what is causing the anomalies in the data. Students use a series of NetLogo agent-based models of an aquatic ecosystem to study how toxins accumulate in the food web. Using these models, students learn about predator-prey relationships, bioaccumulation, and invasive species. Students are confronted with contradictory data collected by scientists and investigate alternative food web mechanisms at work. By studying the individual variables, students learn common scientific principles. When multiple variables are combined in a unifying model, students learn that the interactions lead to unexpected outcomes. Students learn about the complexity of the ecosystem and gain proficiency interpreting computer models and scientific data collection in this curriculum. Model of aquatic food chain

  20. Possible nutrient limiting factor in long term operation of closed aquatic ecosystem

    NASA Astrophysics Data System (ADS)

    Hao, Zongjie; Li, Yanhui; Cai, Wenkai; Wu, Peipei; Liu, Yongding; Wang, Gaohong

    2012-03-01

    To investigate nutrient limitation effect on the community metabolism of closed aquatic ecosystem and possible nutrient limiting factors in the experimental food chains, depletion of inorganic chemicals including carbon, nitrogen and phosphorous was tested. A closed aquatic ecosystem lab module consisting of Chlorella pyrenoidosa and Chlamydomonas reinhardtii, Daphnia magna and associated unidentified microbes was established. Closed ecological systems receive no carbon dioxide; therefore, we presumed carbon as a first limiting factor. The results showed that the algae population in the nutrient saturated group was statistically higher than that in the nutrient limited groups, and that the chlorophyll a content of algae in the phosphorus limited group was the highest among the limited groups. However, the nitrogen limited group supported the most Daphnia, followed by the carbon limited group, the nutrient saturated group and the phosphorus limited group. Redundancy analysis showed that the total phosphorus contents were correlated significantly with the population of algae, and that the amount of soluble carbohydrate as feedback of nutrient depletion was correlated with the number of Daphnia. Thus, these findings suggest that phosphorus is the limiting factor in the operation of closed aquatic ecosystem. The results presented herein have important indications for the future construction of long term closed ecological system.

  1. Environmental fate and biodegradability of benzene derivatives as studied in a model aquatic ecosystem.

    PubMed Central

    Lu, P Y; Metcalf, R L

    1975-01-01

    A model aquatic ecosystem is devised for studying relatively volatile organic compounds and simulating direct discharge of chemical wastes into aquatic ecosystems. Six simple benzene derivatives (aniline, anisole, benzoic acid, chlorobenzene, nitrobenzene, and phthalic anhydride) and other important specialty chemicals: hexachlorobenzene, pentachlorophenol, 2,6-diethylaniline, and 3,5,6-trichloro-2-pyridinol were also chosen for study of environmental behavior and fate in the model aquatic ecosystem. Quantitative relationships of the intrinsic molecular properties of the environmental micropollutants with biological responses are established, e.g., water solubility, partition coefficient, pi constant, sigma constant, ecological magnification, biodegradability index, and comparative detoxication mechanisms, respectively. Water solubility, pi constant, and sigma constant are the most significant factors and control the biological responses of the food chain members. Water solubility and pi constant control the degree of bioaccumulation, and sigma constant limits the metabolism of the xenobiotics via microsomal detoxication enzymes. These highly significant correlations should be useful for predicting environmental fate of organic chemicals. PMID:1157796

  2. Ecological and toxicological effects of inorganic nitrogen pollution in aquatic ecosystems: A global assessment.

    PubMed

    Camargo, Julio A; Alonso, Alvaro

    2006-08-01

    We provide a global assessment, with detailed multi-scale data, of the ecological and toxicological effects generated by inorganic nitrogen pollution in aquatic ecosystems. Our synthesis of the published scientific literature shows three major environmental problems: (1) it can increase the concentration of hydrogen ions in freshwater ecosystems without much acid-neutralizing capacity, resulting in acidification of those systems; (2) it can stimulate or enhance the development, maintenance and proliferation of primary producers, resulting in eutrophication of aquatic ecosystems; (3) it can reach toxic levels that impair the ability of aquatic animals to survive, grow and reproduce. Inorganic nitrogen pollution of ground and surface waters can also induce adverse effects on human health and economy. Because reductions in SO2 emissions have reduced the atmospheric deposition of H2SO4 across large portions of North America and Europe, while emissions of NOx have gone unchecked, HNO3 is now playing an increasing role in the acidification of freshwater ecosystems. This acidification process has caused several adverse effects on primary and secondary producers, with significant biotic impoverishments, particularly concerning invertebrates and fishes, in many atmospherically acidified lakes and streams. The cultural eutrophication of freshwater, estuarine, and coastal marine ecosystems can cause ecological and toxicological effects that are either directly or indirectly related to the proliferation of primary producers. Extensive kills of both invertebrates and fishes are probably the most dramatic manifestation of hypoxia (or anoxia) in eutrophic and hypereutrophic aquatic ecosystems with low water turnover rates. The decline in dissolved oxygen concentrations can also promote the formation of reduced compounds, such as hydrogen sulphide, resulting in higher adverse (toxic) effects on aquatic animals. Additionally, the occurrence of toxic algae can significantly

  3. Field flume reveals aquatic vegetation's role in sediment and particulate phosphorus transport in a shallow aquatic ecosystem

    NASA Astrophysics Data System (ADS)

    Harvey, Judson W.; Noe, Gregory B.; Larsen, Laurel G.; Nowacki, Daniel J.; McPhillips, Lauren E.

    2011-03-01

    Flow interactions with aquatic vegetation and effects on sediment transport and nutrient redistribution are uncertain in shallow aquatic ecosystems. Here we quantified sediment transport in the Everglades by progressively increasing flow velocity in a field flume constructed around undisturbed bed sediment and emergent macrophytes. Suspended sediment < 100 μm was dominant in the lower range of laminar flow and was supplied by detachment from epiphyton. Sediment flux increased by a factor of four and coarse flocculent sediment > 100 μm became dominant at higher velocity steps after a threshold shear stress for bed floc entrainment was exceeded. Shedding of vortices that had formed downstream of plant stems also occurred on that velocity step which promoted additional sediment detachment from epiphyton. Modeling determined that the potentially entrainable sediment reservoir, 46 g m - 2 , was similar to the reservoir of epiphyton (66 g m - 2 ) but smaller than the reservoir of flocculent bed sediment (330 g m - 2 ). All suspended sediment was enriched in phosphorus (by approximately twenty times) compared with bulk sediment on the bed surface and on plant stems, indicating that the most easily entrainable sediment is also the most nutrient rich (and likely the most biologically active).

  4. Field flume reveals aquatic vegetation's role in sediment and particulate phosphorus transport in a shallow aquatic ecosystem

    USGS Publications Warehouse

    Harvey, J.W.; Noe, G.B.; Larsen, L.G.; Nowacki, D.J.; McPhillips, L.E.

    2011-01-01

    Flow interactions with aquatic vegetation and effects on sediment transport and nutrient redistribution are uncertain in shallow aquatic ecosystems. Here we quantified sediment transport in the Everglades by progressively increasing flow velocity in a field flume constructed around undisturbed bed sediment and emergent macrophytes. Suspended sediment 100 μm became dominant at higher velocity steps after a threshold shear stress for bed floc entrainment was exceeded. Shedding of vortices that had formed downstream of plant stems also occurred on that velocity step which promoted additional sediment detachment from epiphyton. Modeling determined that the potentially entrainable sediment reservoir, 46 g m−2, was similar to the reservoir of epiphyton (66 g m−2) but smaller than the reservoir of flocculent bed sediment (330 g m−2). All suspended sediment was enriched in phosphorus (by approximately twenty times) compared with bulk sediment on the bed surface and on plant stems, indicating that the most easily entrainable sediment is also the most nutrient rich (and likely the most biologically active).

  5. Aquatic Ecosystems, Water Quality, and Global Change: Challenges of conducting Multi-Stressor Vulnerability Assessments (External Review Draft)

    EPA Science Inventory

    This draft report investigates the issues and challenges associated with identifying, calculating, and mapping indicators of the relative vulnerability of water quality and aquatic ecosystems, across the United States, to the potential impacts of global change. Using a large set...

  6. Approach for Developing a National Atlas of Vulnerabilities for U.S. Water Quality and Aquatic Ecosystems

    EPA Science Inventory

    The purpose of the Atlas project is to support national- and regional-scale water quality and aquatic ecosystem vulnerability assessments by providing quantitative information on the relative vulnerability to climate change of different geographic regions and watershed systems ac...

  7. A REVIEW OF SINGLE SPECIES TOXICITY TESTS: ARE THE TESTS RELIABLE PREDICTORS OF AQUATIC ECOSYSTEM COMMUNITY RESPONSES?

    EPA Science Inventory

    This document provides a comprehensive review to evaluate the reliability of indicator species toxicity test results in predicting aquatic ecosystem impacts, also called the ecological relevance of laboratory single species toxicity tests.

  8. IMPACT OF HIGH CHEMICAL CONTAMINANT CONCENTRATIONS ON TERRESTRIAL AND AQUATIC ECOSYSTEMS: A STATE-OF-THE-ART REVIEW

    EPA Science Inventory

    The state-of-the-art of available methods for predicting the effects of high chemical concentrations on the properties, processes, functions, cycles, and responses of terrestrial and aquatic ecosystems was reviewed. Environmental problems associated with high chemical concentrati...

  9. Aquatic ecosystem protection and restoration: Advances in methods for assessment and evaluation

    USGS Publications Warehouse

    Bain, M.B.; Harig, A.L.; Loucks, D.P.; Goforth, R.R.; Mills, K.E.

    2000-01-01

    Many methods and criteria are available to assess aquatic ecosystems, and this review focuses on a set that demonstrates advancements from community analyses to methods spanning large spatial and temporal scales. Basic methods have been extended by incorporating taxa sensitivity to different forms of stress, adding measures linked to system function, synthesizing multiple faunal groups, integrating biological and physical attributes, spanning large spatial scales, and enabling simulations through time. These tools can be customized to meet the needs of a particular assessment and ecosystem. Two case studies are presented to show how new methods were applied at the ecosystem scale for achieving practical management goals. One case used an assessment of biotic structure to demonstrate how enhanced river flows can improve habitat conditions and restore a diverse fish fauna reflective of a healthy riverine ecosystem. In the second case, multitaxonomic integrity indicators were successful in distinguishing lake ecosystems that were disturbed, healthy, and in the process of restoration. Most methods strive to address the concept of biological integrity and assessment effectiveness often can be impeded by the lack of more specific ecosystem management objectives. Scientific and policy explorations are needed to define new ways for designating a healthy system so as to allow specification of precise quality criteria that will promote further development of ecosystem analysis tools.

  10. Exploring the Use of Participatory Information to Improve Monitoring, Mapping and Assessment of Aquatic Ecosystem Services at Landascape Scales

    EPA Science Inventory

    Traditionally, the EPA has monitored aquatic ecosystems using statistically rigorous sample designs and intensive field efforts which provide high quality datasets. But by their nature they leave many aquatic systems unsampled, follow a top down approach, have a long lag between ...

  11. LINKING COMMUNITY STRUCTURE AND ECOSYSTEM FUNCTION IN AQUATIC ECOSYSTEMS DEGRADED BY MOUNTAINTOP MINING

    EPA Science Inventory

    The Clean Water Act and its subsequent amendments recognize the importance of protecting biological integrity, a concept synonymous with preserving structure and function within lotic ecosystems. This research will improve current taxonomically based risk assessment models,...

  12. Effects of experimental floods on riparian and aquatic ecosystems: Bill Williams River, Arizona

    NASA Astrophysics Data System (ADS)

    Shafroth, P. B.; Andersen, D. C.; Wilcox, A. C.; Kui, L.; Stella, J. C.

    2013-12-01

    Development of flow prescriptions for environmental purposes along rivers is relatively common, but implementation of these 'environmental flows' occurs infrequently. Implementation is critical for testing hypotheses relating flow regime to biotic response, which ultimately can inform adaptive flow management. We describe the development of flow prescriptions and evaluate responses of riparian vegetation, beaver dams, and associated aquatic habitat to experimental floods and intervening base flows associated with an environmental flow program on the Bill Williams River (BWR), in semiarid Arizona. First, we assessed effects of flow releases between 1993 and 2009 designed to favor the establishment and maintenance of native riparian trees (Populus and Salix) and disfavor an invasive, nonnative shrub (Tamarix spp.) downstream of Alamo Dam on the BWR. Our data are multi-scaled and include a several-decade assessment of changes to major vegetation types based on a time series of aerial photography, an assessment of species composition and abundance sampled in permanent vegetation quadrats, and targeted seedling surveys following experimental floods. Between 1993 and 2009, we observed significant increases in Populus and Salix forests and essentially no change in Tamarix. Experimental floods in 2006 and 2007 resulted in higher mortality of Tamarix seedlings than Salix. These results illustrate the potential for managing streamflow to influence riparian vegetation dynamics, including management of nonnative species. Second, we examined the role of beaver as ecosystem engineers in the BWR and linkages to flow releases between 2004 and 2013. Beaver convert lotic stream habitat to lentic through dam construction and maintenance during low flow periods, and the process is reversed when a flood or other event causes dam failure. We estimated the extent of lotic and beaver-created lentic (beaver pond) habitat along the BWR and related the likelihood of damage or destruction of

  13. Heavy metal pollution in aquatic ecosystems and its phytoremediation using wetland plants: an ecosustainable approach.

    PubMed

    Rai, Prabhat Kumar

    2008-01-01

    This review addresses the global problem of heavymetal pollution originating from increased industrialization and urbanization and its amelioration by using wetland plants both in a microcosm as well as natural/field condition. Heavymetal contamination in aquatic ecosystems due to discharge of industrial effluents may pose a serious threat to human health. Alkaline precipitation, ion exchange columns, electrochemical removal, filtration, and membrane technologies are the currently available technologies for heavy metal removal. These conventional technologies are not economical and may produce adverse impacts on aquatic ecosystems. Phytoremediation of metals is a cost-effective "green" technology based on the use of specially selected metal-accumulating plants to remove toxic metals from soils and water. Wetland plants are important tools for heavy metal removal. The Ramsar convention, one of the earlier modern global conservation treaties, was adopted at Ramsar, Iran, in 1971 and became effective in 1975. This convention emphasized the wise use of wetlands and their resources. This review mentions salient features of wetland ecosystems, their vegetation component, and the pros and cons involved in heavy metal removal. Wetland plants are preferred over other bio-agents due to their low cost, frequent abundance in aquatic ecosystems, and easy handling. The extensive rhizosphere of wetland plants provides an enriched culture zone for the microbes involved in degradation. The wetland sediment zone provides reducing conditions that are conducive to the metal removal pathway. Constructed wetlands proved to be effective for the abatement of heavymetal pollution from acid mine drainage; landfill leachate; thermal power; and municipal, agricultural, refinery, and chlor-alkali effluent. the physicochemical properties of wetlands provide many positive attributes for remediating heavy metals. Typha, Phragmites, Eichhornia, Azolla, Lemna, and other aquatic macrophytes are some

  14. The Role of Biomarkers in the Assessment of Aquatic Ecosystem Health

    PubMed Central

    Hook, Sharon E; Gallagher, Evan P; Batley, Graeme E

    2016-01-01

    Ensuring the health of aquatic ecosystems and identifying species at risk from the detrimental effects of environmental contaminants can be facilitated by integrating analytical chemical analysis with carefully selected biological endpoints measured in tissues of species of concern. These biological endpoints include molecular, biochemical and physiological markers (i.e. biomarkers) that when integrated, can clarify issues of contaminant bioavailability, bioaccumulation and ecological effects while enabling a better understanding of the effects of non-chemical stressors. In the case of contaminant stressors, an understanding of chemical modes of toxicity can be incorporated with diagnostic markers of aquatic animal physiology to help understand the health status of aquatic organisms in the field. Furthermore, new approaches in functional genomics and bioinformatics can help discriminate individual chemicals, or groups of chemicals among complex mixtures that may contribute to adverse biological effects. While the use of biomarkers is not a new paradigm, such approaches have been underutilized in the context of ecological risk assessment and natural resource damage assessment. From a regulatory standpoint, these approaches can help better assess the complex effects from coastal development activities to assessing ecosystem integrity pre- and post-development or site remediation. PMID:24574147

  15. Heavy metal pollution in aquatic ecosystems and its phytoremediation using wetland plants: An ecosustainable approach

    SciTech Connect

    Rai, P.K.

    2008-07-01

    This review addresses the global problem of heavy metal pollution originating from increased industrialization and urbanization and its amelioration by using wetland plants both in a microcosm as well as natural/field condition. This review mentions salient features of wetland ecosystems, their vegetation component, and the pros and cons involved in heavy metal removal. Wetland plants are preferred over other bio-agents due to their low cost, frequent abundance in aquatic ecosystems, and easy handling. Constructed wetlands proved to be effective for the abatement of heavy metal pollution from acid mine drainage; landfill leachate; thermal power; and municipal, agricultural, refinery, and chlor-alkali effluent. the physicochemical properties of wetlands provide many positive attributes for remediating heavy metals. Typha, Phragmites, Eichhornia, Azolla, Lemna, and other aquatic macrophytes are some of the potent wetland plants for heavy metal removal. Biomass disposal problem and seasonal growth of aquatic macrophytes are some limitations in the transfer of phytoremediation technology from the laboratory to the field. However, the disposed biomass of macrophytes may be used for various fruitful applications. An ecosustainable model has been developed through the author's various works, which may ameliorate some of the limitations. The creation of more areas for phytoremediation may also aid in wetlands conservation. Genetic engineering and biodiversity prospecting of endangered wetland plants are important future prospects in this regard.

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

    USGS Publications Warehouse

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

    2009-01-01

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

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

    ERIC Educational Resources Information Center

    Stevenson, R. D.

    These materials were designed to be used by life science students for instruction in the application of physical theory to ecosystem operation. Most modules contain computer programs which are built around a particular application of a physical process. This module and a comparison module are concerned with elementary concepts of thermodynamics as…

  18. Watershed land use and aquatic ecosystem response: Ecohydrologic approach to conservation policy

    NASA Astrophysics Data System (ADS)

    Randhir, Timothy O.; Hawes, Ashley G.

    2009-01-01

    SummaryLand use activities change the natural functions of a watershed impacting the flow of water and water quality, and impair aquatic ecosystems. Optimal allocation of land use depends on attributes related to terrestrial and aquatic environments. A dynamic model that links land use, overland flow, suspended sediment, and an aquatic species is used to evaluate alternate land use policies. The dwarf wedge mussel that is classified as endangered in the region is used as an indicator species of aquatic health in a watershed in Massachusetts. The simulation model is used to evaluate spatial nature of processes and land use policies. Spatial and temporal changes in runoff, sediment loading, and mussel population are modeled over a period of 4 years. Ten policy scenarios represent combinations of best management practices and development of agriculture and urban land at spatial locations of headwaters, main stem regions, riparian, and entire watershed. Increasing the proportion of agriculture and high density residential land use increased runoff, while increasing the frequency and magnitude of peak flows in the watershed. Sediment loading increased with an increased proportion of agriculture area and decreased with an expansion of high density residential area. Scenarios with an increase in sediment loading above the baseline mean exhibited an irregular recovery of the mussel population from high loading events. Policy implications include the need for best management practices to decrease runoff and sediment loading in the watershed, through education and incentive programs.

  19. A review of ecological effects and environmental fate of illicit drugs in aquatic ecosystems.

    PubMed

    Rosi-Marshall, E J; Snow, D; Bartelt-Hunt, S L; Paspalof, A; Tank, J L

    2015-01-23

    Although illicit drugs are detected in surface waters throughout the world, their environmental fate and ecological effects are not well understood. Many illicit drugs and their breakdown products have been detected in surface waters and temporal and spatial variability in use translates into "hot spots and hot moments" of occurrence. Illicit drug occurrence in regions of production and use and areas with insufficient wastewater treatment are not well studied and should be targeted for further study. Evidence suggests that illicit drugs may not be persistent, as their half-lives are relatively short, but may exhibit "pseudo-persistence" wherein continual use results in persistent occurrence. We reviewed the literature on the ecological effects of these compounds on aquatic organisms and although research is limited, a wide array of aquatic organisms, including bacteria, algae, invertebrates, and fishes, have receptors that make them potentially sensitive to these compounds. In summary, illicit drugs occur in surface waters and aquatic organisms may be affected by these compounds; research is needed that focuses on concentrations of illicit drugs in areas of production and high use, environmental fate of these compounds, and effects of these compounds on aquatic ecosystems at the concentrations that typically occur in the environment. PMID:25062553

  20. Transfer of a cyanobacterial neurotoxin within a temperate aquatic ecosystem suggests pathways for human exposure

    PubMed Central

    Jonasson, Sara; Eriksson, Johan; Berntzon, Lotta; Spáčil, Zdenĕk; Ilag, Leopold L.; Ronnevi, Lars-Olof; Rasmussen, Ulla; Bergman, Birgitta

    2010-01-01

    β-methylamino-L-alanine (BMAA), a neurotoxic nonprotein amino acid produced by most cyanobacteria, has been proposed to be the causative agent of devastating neurodegenerative diseases on the island of Guam in the Pacific Ocean. Because cyanobacteria are widespread globally, we hypothesized that BMAA might occur and bioaccumulate in other ecosystems. Here we demonstrate, based on a recently developed extraction and HPLC-MS/MS method and long-term monitoring of BMAA in cyanobacterial populations of a temperate aquatic ecosystem (Baltic Sea, 2007–2008), that BMAA is biosynthesized by cyanobacterial genera dominating the massive surface blooms of this water body. BMAA also was found at higher concentrations in organisms of higher trophic levels that directly or indirectly feed on cyanobacteria, such as zooplankton and various vertebrates (fish) and invertebrates (mussels, oysters). Pelagic and benthic fish species used for human consumption were included. The highest BMAA levels were detected in the muscle and brain of bottom-dwelling fishes. The discovery of regular biosynthesis of the neurotoxin BMAA in a large temperate aquatic ecosystem combined with its possible transfer and bioaccumulation within major food webs, some ending in human consumption, is alarming and requires attention. PMID:20439734

  1. Mediterranean coastal lagoons in an ecosystem and aquatic resources management context

    NASA Astrophysics Data System (ADS)

    Pérez-Ruzafa, A.; Marcos, C.; Pérez-Ruzafa, I. M.

    Aquatic ecosystems, water resources and their management are some of the main problems facing humanity. These problems vary from water scarcity and deteriorating quality for human consumption and use, to floods in areas with torrential rainfall, rising sea levels in coastal zones, the overexploitation of living resources and the loss of ecological quality and biodiversity. Proper water management needs to follow a hierarchical perspective, ranging from the whole planet to individual water bodies. Spatio-temporal scales change at each level, as do driving forces, impacts, and the processes and responses involved. Recently, the European Union adopted the Water Framework Directive (WFD) to establish the basic principles of sustainable water policy in member states, one of the main concerns being the need to consider the vulnerability of coastal aquatic ecosystems and to establish their ecological status. However, from a Mediterranean point of view, the actions of European countries (under the WFD regulations) and non-EU countries need to be coordinated. There are more than 100 coastal lagoons in the Mediterranean. They are habitats with an important ecological role, but also provide essentials goods and services for humans. In the present work, we look at the problems involved in understanding their definition and management. At water body management level, we emphasise that scientific cooperation is necessary to deal with the conceptual and ecological difficulties derived from inter and intra-lagoon variability in hydrology and biological assemblages, inherent factors in the functioning of these complex ecosystems.

  2. Impacts of aquatic nonindigenous invasive species on the Lake Erie ecosystem

    USGS Publications Warehouse

    Austen, Madeline J.W.; Ciborowski, Jan J.H.; Corkum, Lynda D.; Johnson, Tim B.; MacIsaac, Hugh J.; Metcalfe-Smith, Janice L.; Schloesser, Donald W.; George, Sandra E.

    2002-01-01

    Lake Erie is particularly vulnerable to the introduction and establishment of aquatic nonindigenous invasive species (NIS) populations. A minimum of 144 aquatic NIS have been recorded in the Lake Erie basin including several species [e.g., Eurasian watermilfoil (Myriophyllum spicatum); zebra mussel (Dreissena polymorpha); quagga mussel (Dreissena bugensis); an amphipod (Echinogammarus ischnus); round goby (Neogobius melanostomus); and sea lamprey (Petromyzon marinus)] that have had discernible impacts on the lake's ecology. NIS pose threats to the Lake Erie ecosystem for a variety of reasons including their ability to proliferate quickly, compete with native species, and transfer contaminants (e.g., PCBs) and disease through the food web. Six of the 14 beneficial use impairments listed in Annex 2 of the Great Lakes Water Quality Agreement are impaired in Lake Erie, in part as a result of the introduction of NIS. The Lake Erie Lakewide Management Plan (LaMP) has adopted an ecosystem approach to restore beneficial use impairments in the lake. Furthermore, a research consortium, known as the Lake Erie Millennium Network, is working alongside the LaMP, to address research problems regarding NIS, the loss of habitat, and the role of contaminants in the Lake Erie ecosystem.

  3. Measures to reduce pesticide spray drift in a small aquatic ecosystem in vineyard estate.

    PubMed

    Vischetti, Costantino; Cardinali, Alessandra; Monaci, Elga; Nicelli, Marco; Ferrari, Federico; Trevisan, Marco; Capri, Ettore

    2008-01-25

    A field experiment is reported to ascertain the drift of two pesticides (chlorpyrifos and metalaxyl) in a vineyard in Italian climatic conditions and the effect of mitigation measures, such as buffer zones and tree rows, on pesticide drift contamination in a small aquatic system located inside the field. Results indicated that, in typical Italian agricultural conditions, spray drift in vineyards occurs at a distance of more than 24 m and adequate buffer zones are required to protect surface water bodies from direct contamination. The presence of tree rows in front of the water body inside the agricultural field, against the main wind direction, resulted in a very high reduction of the spray drift and of the ecotoxicological risk for aquatic ecosystem. In addition, a comparison between the data obtained in the experiment and the Drift Calculator procedure showed that the model failed when the procedure is used for short distances. However, concordance was found in terms of maximum drift distances. PMID:17936878

  4. Quantifying Biogeochemical Cycles of CO2 and CH4 over the Land and Aquatic Ecosystems in Northern Eurasia

    NASA Astrophysics Data System (ADS)

    Zhuang, Q.

    2015-12-01

    Under the auspices of the NASA Land-Use and Land-Cover Change Program, we have made a significant progress on quantifying both CO2 and CH4 biogeochemical cycles of the land and aquatic systems in Northern Eurasia over the last several decades. Our quantification is based on in situ and satellite data of ecosystem distribution, land cover distribution, carbon, water and energy fluxes, fire disturbances, plant biomass inventory, atmospheric CO2 and CH4, and meteorology. The evaluated process-based modeling systems for both land and aquatic ecosystems for the historical period have been used to project carbon fluxes during the 21st century over this region. The uncertainty associated with these carbon-based gases is also quantified. This presentation will update these quantifications by examining: 1) the impacts of fire disturbances on land ecosystem CO2 budget in the last few decades; 2) net CO2 and CH4 exchanges of the land and aquatic ecosystems in both historical and future periods. Our study has also assessed the role of permafrost dynamics in both land and aquatic ecosystem carbon and water dynamics in this region. Our research provides an integrated land and aquatic ecosystem model that can be used to address biogeochemical cycles of carbon and water in this climate-sensitive region.

  5. Water quality assessment of aquatic ecosystems using ecological criteria – case study in Bulgaria

    PubMed Central

    Damyanova, Sonya; Ivanova, Iliana; Ignatova, Nadka

    2014-01-01

    Four aquatic ecosystems (two rivers and two dams) situated in the western part of Bulgaria were investigated over a three years’ period. The River Egulya and Petrohan dam are situated in mountainous regions at about 1000 m altitude, and are not influenced by any anthropogenic sources. Petrohan dam is a site for long-term ecosystem research as a part of Bulgarian long-term ecological research network. The other two systems belong to populated industrial areas. The River Martinovska flows through a region with former long-term mining activity, while Ogosta dam is near a battery production factory. Both the geochemical and geographical ecosystems’ conditions are different, and their social usage as well. Ogosta dam water is used for irrigation and Petrohan dam for electric supply. The ecosystem sensitivity to heavy metals was evaluated by a critical load approach. Two criteria were used for risk assessment: critical load exceedance and microbial toxicity test. All studied ecosystems were more sensitive to cadmium than to lead deposition. The potential risk of Cd damage is higher for Petrohan dam and the River Egulya, where critical load exceedance was calculated for two years. Pseudomonas putida growth inhibition test detected a lack of toxicity for all studied ecosystems at the time of investigation with the exception of the low water September sample of the River Martinovska. The fast bacterial test is very suitable for a regular measurement of water toxicity because of its simplicity, lack of sophisticated equipment and clear results. PMID:26019591

  6. Assessment of variables controlling nitrate dynamics in groundwater: is it a threat to surface aquatic ecosystems?

    PubMed

    Rasiah, V; Armour, J D; Cogle, A L

    2005-01-01

    The impact of fertilised cropping on nitrate-N dynamics in groundwater (GW) was assessed in a catchment from piezometers installed: (i) to different depths, (ii) in different soil types, (iii) on different positions on landscape, and (iv) compared with the Australian and New Zealand Environmental and Conservation Council guideline values provided for different aquatic ecosystems. The GW and NO(3)-N concentration dynamics were monitored in 39 piezometer wells, installed to 5-90 m depth, under fertilized sugarcane (Saccharum officinarum-S) in the Johnstone River Catchment, Australia, from 1999 January through September 2002. The median nitrate-N concentration ranged from 14 to 1511 microg L(-1), and the 80th percentile from 0 to 1341 microg L(-1). In 34 out of the 39 piezometer wells the 80th percentile or 80% of the nitrate-N values were higher than 30 microg L(-1), which is the maximum trigger value provided in the ANZECC table for sustainable health of different aquatic ecosystems. Nitrate-N concentration decreased with increasing well depth, increasing depth of water in wells, and with decreasing relief on landscape. Nitrate-N was higher in alluvial soil profiles than on those formed in-situ. Nitrate-N increased with increasing rainfall at the beginning of the rainy season, fluctuated during the peak rainy period, and then decreased when the rain ceased. The rapid decrease in GW after the rains ceased suggested potential existed for nitrate-N to be discharged as lateral-flow into streams. This may contribute towards the deterioration in the health of down-stream aquatic ecosystems. PMID:15757708

  7. Imperiled mammalian fauna of aquatic ecosystems in the Southeast: A historical perspective: Chapter 9

    USGS Publications Warehouse

    Harvey, M.J.; Clark, J.D.

    1997-01-01

    The passage of the U.S. Endangered Species Act of 1973 resulted in an increased need for information concerning distribution and status of all native species. However, relatively little is known concerning the historical distribution and current status of many mammalian taxa, and this is particularly so for small non-game species. In this chapter we provide species accounts of mammals commonly associated with aquatic ecosystems that we consider to be imperiled in the southeastern United States. In these accounts we have included information which we feel is valuable toward best understanding the threats that challenge each considered taxon.

  8. Hydro-Geomorphic Variability as an Ecological Template for Aquatic and Riparian Ecosystems

    NASA Astrophysics Data System (ADS)

    Montgomery, D. R.

    2002-12-01

    Hydro-geomorphic processes act as ecological disturbances that shape ecosystem characteristics and dynamics and play key roles in creating, modifying, and destroying aquatic habitat. Within the broad regional context set by general patterns of climate, geology, topography, and vegetation, the combined influences of the hydrologic, geomorphic, and vegetation regimes dominate the variability of river systems. Of particular relevance to aquatic and riparian ecosystems are the main processes that transport and store water, sediment, and wood, and how differences in current and potential conditions are related to both local conditions and basin-wide tends. The concept of process domains, distinct areas of a landscape that correspond to different disturbance regimes, provides a framework for integrating the inherent interplay of spatial and temporal variability in channel processes. The intensity of the impact, the size of the area affected, and the frequency of occurrence together define the disturbance regime associated with particular hydro-geomorphic processes. The disturbance regime sets the physical habitat template that influences potentially successful behavioral and life-history strategies of stream dwelling organisms. The distribution of some organisms is strongly associated with different process domains, whereas that of habitat generalists are not. Three general principles apply to the use of hydro-geomorphic variability as an ecological template for aquatic and riparian ecosystems. (1) What constitutes a disturbance is species specific and will vary according to the system or community under consideration and focusing on needs of a single target species and life stage can unintentionally degrade the system for other species or life stages. For example, river restoration efforts focused on spawning reaches and water levels for chinook salmon may ignore or exacerbate the loss of off-channel habitat such as side channels, groundwater-fed floodplain channels

  9. Adaptive genetic variation mediates bottom-up and top-down control in an aquatic ecosystem

    PubMed Central

    Rudman, Seth M.; Rodriguez-Cabal, Mariano A.; Stier, Adrian; Sato, Takuya; Heavyside, Julian; El-Sabaawi, Rana W.; Crutsinger, Gregory M.

    2015-01-01

    Research in eco-evolutionary dynamics and community genetics has demonstrated that variation within a species can have strong impacts on associated communities and ecosystem processes. Yet, these studies have centred around individual focal species and at single trophic levels, ignoring the role of phenotypic variation in multiple taxa within an ecosystem. Given the ubiquitous nature of local adaptation, and thus intraspecific variation, we sought to understand how combinations of intraspecific variation in multiple species within an ecosystem impacts its ecology. Using two species that co-occur and demonstrate adaptation to their natal environments, black cottonwood (Populus trichocarpa) and three-spined stickleback (Gasterosteus aculeatus), we investigated the effects of intraspecific phenotypic variation on both top-down and bottom-up forces using a large-scale aquatic mesocosm experiment. Black cottonwood genotypes exhibit genetic variation in their productivity and consequently their leaf litter subsidies to the aquatic system, which mediates the strength of top-down effects from stickleback on prey abundances. Abundances of four common invertebrate prey species and available phosphorous, the most critically limiting nutrient in freshwater systems, are dictated by the interaction between genetic variation in cottonwood productivity and stickleback morphology. These interactive effects fit with ecological theory on the relationship between productivity and top-down control and are comparable in strength to the effects of predator addition. Our results illustrate that intraspecific variation, which can evolve rapidly, is an under-appreciated driver of community structure and ecosystem function, demonstrating that a multi-trophic perspective is essential to understanding the role of evolution in structuring ecological patterns. PMID:26203004

  10. Adaptive genetic variation mediates bottom-up and top-down control in an aquatic ecosystem.

    PubMed

    Rudman, Seth M; Rodriguez-Cabal, Mariano A; Stier, Adrian; Sato, Takuya; Heavyside, Julian; El-Sabaawi, Rana W; Crutsinger, Gregory M

    2015-08-01

    Research in eco-evolutionary dynamics and community genetics has demonstrated that variation within a species can have strong impacts on associated communities and ecosystem processes. Yet, these studies have centred around individual focal species and at single trophic levels, ignoring the role of phenotypic variation in multiple taxa within an ecosystem. Given the ubiquitous nature of local adaptation, and thus intraspecific variation, we sought to understand how combinations of intraspecific variation in multiple species within an ecosystem impacts its ecology. Using two species that co-occur and demonstrate adaptation to their natal environments, black cottonwood (Populus trichocarpa) and three-spined stickleback (Gasterosteus aculeatus), we investigated the effects of intraspecific phenotypic variation on both top-down and bottom-up forces using a large-scale aquatic mesocosm experiment. Black cottonwood genotypes exhibit genetic variation in their productivity and consequently their leaf litter subsidies to the aquatic system, which mediates the strength of top-down effects from stickleback on prey abundances. Abundances of four common invertebrate prey species and available phosphorous, the most critically limiting nutrient in freshwater systems, are dictated by the interaction between genetic variation in cottonwood productivity and stickleback morphology. These interactive effects fit with ecological theory on the relationship between productivity and top-down control and are comparable in strength to the effects of predator addition. Our results illustrate that intraspecific variation, which can evolve rapidly, is an under-appreciated driver of community structure and ecosystem function, demonstrating that a multi-trophic perspective is essential to understanding the role of evolution in structuring ecological patterns. PMID:26203004

  11. RESEARCH SHOWS IMPORTANCE OF RIPARIAN BUFFERS FOR AQUATIC HEALTH

    EPA Science Inventory

    Issue: Excess nitrogen from fertilizer, septic tanks, animal feedlots, and runoff from pavement can threaten aquatic ecosystem health. Riparian buffers -- the vegetated region adjacent to streams and wetlands -- are thought to be effective at intercepting and controlling excess ...

  12. Presence of the Neurotoxin BMAA in Aquatic Ecosystems: What Do We Really Know?

    PubMed Central

    Faassen, Elisabeth J.

    2014-01-01

    The neurotoxin β-N-methylamino-l-alanine (BMAA) is suspected to play a role in the neurological diseases amyotrophic lateral sclerosis, Alzheimer’s disease, and Parkinson’s disease. BMAA production by cyanobacteria has been reported and contact with cyanobacteria infested waters or consumption of aquatic organisms are possible pathways to human exposure. However, there is little consensus regarding whether BMAA is present in cyanobacteria or not, and if so, at what concentrations. The aim of this review is to indicate the current state of knowledge on the presence of BMAA in aquatic ecosystems. Some studies have convincingly shown that BMAA can be present in aquatic samples at the µg/g dry weight level, which is around the detection limit of some equally credible studies in which no BMAA was detected. However, for the majority of the reviewed articles, it was unclear whether BMAA was correctly identified, either because inadequate analytical methods were used, or because poor reporting of analyses made it impossible to verify the results. Poor analysis, reporting and prolific errors have shaken the foundations of BMAA research. First steps towards estimation of human BMAA exposure are to develop and use selective, inter-laboratory validated methods and to correctly report the analytical work. PMID:24662480

  13. Presence of the neurotoxin BMAA in aquatic ecosystems: what do we really know?

    PubMed

    Faassen, Elisabeth J

    2014-03-01

    The neurotoxin β-N-methylamino-L-alanine (BMAA) is suspected to play a role in the neurological diseases amyotrophic lateral sclerosis, Alzheimer's disease, and Parkinson's disease. BMAA production by cyanobacteria has been reported and contact with cyanobacteria infested waters or consumption of aquatic organisms are possible pathways to human exposure. However, there is little consensus regarding whether BMAA is present in cyanobacteria or not, and if so, at what concentrations. The aim of this review is to indicate the current state of knowledge on the presence of BMAA in aquatic ecosystems. Some studies have convincingly shown that BMAA can be present in aquatic samples at the µg/g dry weight level, which is around the detection limit of some equally credible studies in which no BMAA was detected. However, for the majority of the reviewed articles, it was unclear whether BMAA was correctly identified, either because inadequate analytical methods were used, or because poor reporting of analyses made it impossible to verify the results. Poor analysis, reporting and prolific errors have shaken the foundations of BMAA research. First steps towards estimation of human BMAA exposure are to develop and use selective, inter-laboratory validated methods and to correctly report the analytical work. PMID:24662480

  14. Does the current fungicide risk assessment provide sufficient protection for key drivers in aquatic ecosystem functioning?

    PubMed

    Zubrod, Jochen P; Englert, Dominic; Feckler, Alexander; Koksharova, Natalia; Konschak, Marco; Bundschuh, Rebecca; Schnetzer, Nadja; Englert, Katja; Schulz, Ralf; Bundschuh, Mirco

    2015-01-20

    The level of protection provided by the present environmental risk assessment (ERA) of fungicides in the European Union for fungi is unknown. Therefore, we assessed the structural and functional implications of five fungicides with different modes of action (azoxystrobin, carbendazim, cyprodinil, quinoxyfen, and tebuconazole) individually and in mixture on communities of aquatic hyphomycetes. This is a polyphyletic group of fungi containing key drivers in the breakdown of leaf litter, governing both microbial leaf decomposition and the palatability of leaves for leaf-shredding macroinvertebrates. All fungicides impaired leaf palatability to the leaf-shredder Gammarus fossarum and caused structural changes in fungal communities. In addition, all compounds except for quinoxyfen altered microbial leaf decomposition. Our results suggest that the European Union’s first-tier ERA provides sufficient protection for the tested fungicides, with the exception of tebuconazole and the mixture, while higher-tier ERA does not provide an adequate level of protection for fungicides in general. Therefore, our results show the need to incorporate aquatic fungi as well as their functions into ERA testing schemes to safeguard the integrity of aquatic ecosystems. PMID:25517729

  15. Life cycle impacts of topsoil erosion on aquatic ecosystems: case study on Eucalyptus globulus forest

    NASA Astrophysics Data System (ADS)

    Quinteiro, Paula; Van de Broek, Marijn; Cláudia Dias, Ana; Ridoutt, Bradley; Arroja, Luís

    2016-04-01

    High concentrations of suspended solids (SS), particularly in the clay and silt size fractions, reaching lotic environments and remaining in suspension can be a significant stressors to the biodiversity of these aquatic systems, degrading the water quality and directly affecting the aquatic biota, namely macroinvertebrates, algae and macrophytes. This damage is presently not considered in Life Cycle Assessment studies. This study is devoted to the effects of SS into freshwater systems due to topsoil erosion by water (environmental mechanism), translated into damage to aquatic ecosystem diversity (endpoint impact category), namely to macroinvertebrates, algae and macrophytes. For this, we have developed a framework to conduct an erosion inventory using the WaTEM/SEDEM model and linked this with, a method to derive regional characterisation for endpoint damage on aquatic ecosystem diversity. A case study was performed for Eucalyptus globulus stands in Portugal, with a functional unit of one hectare of land under production forestry management. To demonstrate how this newly SS ecosystem method can help to improve the environmental assessment in forestry, results were compared with the earlier commonly used impact categories from ReCiPe method. The relevance of the impact from SS delivery to freshwater streams is shown, providing a more comprehensive assessment of the SS impact from land use systems on aquatic environments. The SS impacts ranged from 15.5 to 1234.9 PDF.m3.yr.ha-1.revolution-1 for macroinvertebrates, and from 5.2 to 411.9 PDF.m3.yr.ha-1.revolution-1 for algae and macrophytes. For some stands, SS potential impacts on macroinvertebrates have the same order of magnitude than freshwater eutrophication, freshwater ecotoxicity, terrestrial ecotoxicity and terrestrial acidification impacts. For algae and macrophytes, most of the stands present SS impacts of the same order of magnitude as terrestrial ecotoxicity, one order of magnitude higher than freshwater

  16. After the Storm: Assessing the carbon and nitrogen leaching potential from sediments deposited in aquatic ecosystems

    NASA Astrophysics Data System (ADS)

    Johnson, E. R.; Krieg, C.; Canning, C.; Inamdar, S. P.; Rowland, R. D.

    2015-12-01

    The erosive energy of large storms can mobilize, and subsequently deposit large amounts of sediment in receiving aquatic ecosystems. Depending on the character of the sediments there is potential for leaching or sequestration of carbon (C) and nitrogen (N) from the sediments. This could have significant implications for water quality, aquatic metabolism, and global cycling of C and N. This study examines the fate of these sediments by: (1) determining the amount and quality of organic matter that can be leached into the surrounding water from coarse, medium and fine particle classes (2) assessing the C and N contents of various particles classes and the sources of the sediment through isotopic composition. Bed sediment samples were collected along a 1-2nd order stream (eight locations) in a forested catchment in the Piedmont region of Maryland following a large storm event. Samples were sieved into three particle classes - coarse (2mm-1mm), medium (1mm-250µm) and fine (<250µm). Extractions were performed for each of three particle class sizes by leaching with DI water. Organic matter composition for the extracts was characterized using fluorescence. Stable isotopes of 13C and 15N were determined for bed sediment classes and upland source sediments to identify the origins of the eroded sediments. Extracts with low C:N ratios that also exhibit a higher percent protein and lower percent humic carbon content are considered most labile. Within the bed sediment deposits, differences were found in the distribution of labile compounds between each particle class size. Generally, course particle size exhibited the most labile characteristics, closely followed by medium particle size. Fine particle size exhibited the most refractory characteristics in all locations. These results are critical since climate-change predictions reveal more intense and large storms for the northeast US, with potentially greater impacts on aquatic ecosystems from eroded upland sediments.

  17. Cascading effects of induced terrestrial plant defences on aquatic and terrestrial ecosystem function

    PubMed Central

    Jackrel, Sara L.; Wootton, J. Timothy

    2015-01-01

    Herbivores induce plants to undergo diverse processes that minimize costs to the plant, such as producing defences to deter herbivory or reallocating limited resources to inaccessible portions of the plant. Yet most plant tissue is consumed by decomposers, not herbivores, and these defensive processes aimed to deter herbivores may alter plant tissue even after detachment from the plant. All consumers value nutrients, but plants also require these nutrients for primary functions and defensive processes. We experimentally simulated herbivory with and without nutrient additions on red alder (Alnus rubra), which supplies the majority of leaf litter for many rivers in western North America. Simulated herbivory induced a defence response with cascading effects: terrestrial herbivores and aquatic decomposers fed less on leaves from stressed trees. This effect was context dependent: leaves from fertilized-only trees decomposed most rapidly while leaves from fertilized trees receiving the herbivory treatment decomposed least, suggesting plants funnelled a nutritionally valuable resource into enhanced defence. One component of the defence response was a decrease in leaf nitrogen leading to elevated carbon : nitrogen. Aquatic decomposers prefer leaves naturally low in C : N and this altered nutrient profile largely explains the lower rate of aquatic decomposition. Furthermore, terrestrial soil decomposers were unaffected by either treatment but did show a preference for local and nitrogen-rich leaves. Our study illustrates the ecological implications of terrestrial herbivory and these findings demonstrate that the effects of selection caused by terrestrial herbivory in one ecosystem can indirectly shape the structure of other ecosystems through ecological fluxes across boundaries. PMID:25788602

  18. Dynamic exchanges between DOM and POM pools in coastal and inland aquatic ecosystems: A review.

    PubMed

    He, Wei; Chen, Meilian; Schlautman, Mark A; Hur, Jin

    2016-05-01

    Dynamic exchanges between dissolved organic matter (DOM) and particulate organic matter (POM) plays a critical role in organic carbon cycling in coastal and inland aquatic ecosystems, interactions with aquatic organisms, mobility and bioavailability of pollutants, among many other ecological and geochemical phenomena. Although DOM-POM exchange processes have been widely studied from different aspects, little to no effort has been made to date to provide a comprehensive, mechanistic, and micro-spatial schema for understanding various exchange processes occurring in different aquatic ecosystems in a unified way. The phenomena occurring between DOM and POM were explained here with the homogeneous and heterogeneous mechanisms. In the homogeneous mechanism, the participating components are only organic matter (OM) constituents themselves with aggregation and dissolution involved, whereas OM is associated with other components such as minerals and particulate colloids in the heterogeneous counterpart. Besides the generally concerned processes of aggregation/dissolution and adsorption/desorption, other ecological factors such as sunlight and organisms can also participate in DOM-POM exchanges through altering the chemical nature of OM. Despite the limitation of current analytical technologies, many unknown and/or unquantified processes need to be identified to unravel the complicated exchanges of OM between its dissolved and particulate states. Based on the review of several previous mathematical models, we proposed a unified conceptual model to describe all major dynamic exchange mechanisms on the basis of exergy theory. More knowledge of dynamic DOM-POM exchanges is warranted to overcome the potential problems arising from a simple division of OM into dissolved versus particulate states and to further develop more sophisticated mathematic models. PMID:26881732

  19. Cascading effects of induced terrestrial plant defences on aquatic and terrestrial ecosystem function.

    PubMed

    Jackrel, Sara L; Wootton, J Timothy

    2015-04-22

    Herbivores induce plants to undergo diverse processes that minimize costs to the plant, such as producing defences to deter herbivory or reallocating limited resources to inaccessible portions of the plant. Yet most plant tissue is consumed by decomposers, not herbivores, and these defensive processes aimed to deter herbivores may alter plant tissue even after detachment from the plant. All consumers value nutrients, but plants also require these nutrients for primary functions and defensive processes. We experimentally simulated herbivory with and without nutrient additions on red alder (Alnus rubra), which supplies the majority of leaf litter for many rivers in western North America. Simulated herbivory induced a defence response with cascading effects: terrestrial herbivores and aquatic decomposers fed less on leaves from stressed trees. This effect was context dependent: leaves from fertilized-only trees decomposed most rapidly while leaves from fertilized trees receiving the herbivory treatment decomposed least, suggesting plants funnelled a nutritionally valuable resource into enhanced defence. One component of the defence response was a decrease in leaf nitrogen leading to elevated carbon : nitrogen. Aquatic decomposers prefer leaves naturally low in C : N and this altered nutrient profile largely explains the lower rate of aquatic decomposition. Furthermore, terrestrial soil decomposers were unaffected by either treatment but did show a preference for local and nitrogen-rich leaves. Our study illustrates the ecological implications of terrestrial herbivory and these findings demonstrate that the effects of selection caused by terrestrial herbivory in one ecosystem can indirectly shape the structure of other ecosystems through ecological fluxes across boundaries. PMID:25788602

  20. Effects of UV radiation on aquatic ecosystems and interactions with other environmental factors.

    PubMed

    Häder, Donat-P; Williamson, Craig E; Wängberg, Sten-Åke; Rautio, Milla; Rose, Kevin C; Gao, Kunshan; Helbling, E Walter; Sinha, Rajeshwar P; Worrest, Robert

    2015-01-01

    Interactions between climate change and UV radiation are having strong effects on aquatic ecosystems due to feedback between temperature, UV radiation, and greenhouse gas concentration. Higher air temperatures and incoming solar radiation are increasing the surface water temperatures of lakes and oceans, with many large lakes warming at twice the rate of regional air temperatures. Warmer oceans are changing habitats and the species composition of many marine ecosystems. For some, such as corals, the temperatures may become too high. Temperature differences between surface and deep waters are becoming greater. This increase in thermal stratification makes the surface layers shallower and leads to stronger barriers to upward mixing of nutrients necessary for photosynthesis. This also results in exposure to higher levels of UV radiation of surface-dwelling organisms. In polar and alpine regions decreases in the duration and amount of snow and ice cover on lakes and oceans are also increasing exposure to UV radiation. In contrast, in lakes and coastal oceans the concentration and colour of UV-absorbing dissolved organic matter (DOM) from terrestrial ecosystems is increasing with greater runoff from higher precipitation and more frequent extreme storms. DOM thus creates a refuge from UV radiation that can enable UV-sensitive species to become established. At the same time, decreased UV radiation in such surface waters reduces the capacity of solar UV radiation to inactivate viruses and other pathogens and parasites, and increases the difficulty and price of purifying drinking water for municipal supplies. Solar UV radiation breaks down the DOM, making it more available for microbial processing, resulting in the release of greenhouse gases into the atmosphere. In addition to screening solar irradiance, DOM, when sunlit in surface water, can lead to the formation of reactive oxygen species (ROS). Increases in carbon dioxide are in turn acidifying the oceans and inhibiting

  1. Aquatic bird disease and mortality as an indicator of changing ecosystem health

    USGS Publications Warehouse

    Newman, Scott H.; Chmura, Aleksei; Converse, Kathy; Kilpatrick, A. Marm; Patel, Nikkita; Lammers, Emily; Daszak, Peter

    2007-01-01

    We analyzed data from pathologic investigations in the United States, collected by the USGS National Wildlife Health Center between 1971 and 2005, into aquatic bird mortality events. A total of 3619 mortality events was documented for aquatic birds, involving at least 633 708 dead birds from 158 species belonging to 23 families. Environmental causes accounted for the largest proportion of mortality events (1737 or 48%) and dead birds (437 258 or 69%); these numbers increased between 1971 and 2000, with biotoxin mortalities due to botulinum intoxication (Types C and E) being the leading cause of death. Infectious diseases were the second leading cause of mortality events (20%) and dead birds (20%), with both viral diseases, including duck plague (Herpes virus), paramyxovirus of cormorants (Paramyxovirus PMV1) and West Nile virus (Flavivirus), and bacterial diseases, including avian cholera (Pasteurella multocida), chlamydiosis (Chalmydia psittici), and salmonellosis (Salmonella sp.), contributing. Pelagic, coastal marine birds and species that use marine and freshwater habitats were impacted most frequently by environmental causes of death, with biotoxin exposure, primarily botulinum toxin, resulting in mortalities of both coastal and freshwater species. Pelagic birds were impacted most severely by emaciation and starvation, which may reflect increased anthropogenic pressure on the marine habitat from over-fishing, pollution, and other factors. Our study provides important information on broad trends in aquatic bird mortality and highlights how long-term wildlife disease studies can be used to identify anthropogenic threats to wildlife conservation and ecosystem health. In particular, mortality data for the past 30 yr suggest that biotoxins, viral, and bacterial diseases could have impacted >5 million aquatic birds.

  2. Aquatic bird disease and mortality as an indicator of changing ecosystem health

    USGS Publications Warehouse

    Newman, S.H.; Chmura, A.; Converse, K.; Kilpatrick, A.M.; Patel, N.; Lammers, E.; Daszak, P.

    2007-01-01

    We analyzed data from pathologic investigations in the United States, collected by the USGS National Wildlife Health Center between 1971 and 2005, into aquatic bird mortality events. A total of 3619 mortality events was documented for aquatic birds, involving at least 633 708 dead birds from 158 species belonging to 23 families. Environmental causes accounted for the largest proportion of mortality events (1737 or 48%) and dead birds (437 258 or 69%); these numbers increased between 1971 and 2000, with biotoxin mortalities due to botulinum intoxication (Types C and E) being the leading cause of death. Infectious diseases were the second leading cause of mortality events (20%) and dead birds (20 %), with both viral diseases, including duck plague (Herpes virus), paramyxovirus of cormorants (Paramyxovirus PMV1) and West Nile virus (Flavivirus), and bacterial diseases, including avian cholera (Pasteurella multocida), chlamydiosis (Chalmydia psittici), and salmonellosis (Salmonella sp.), contributing. Pelagic, coastal marine birds and species that use marine and freshwater habitats were impacted most frequently by environmental causes of death, with biotoxin exposure, primarily botulinum toxin, resulting in mortalities of both coastal and freshwater species. Pelagic birds were impacted most severely by emaciation and starvation, which may reflect increased anthropogenic pressure on the marine habitat from over-fishing, pollution, and other factors. Our study provides important information on broad trends in aquatic bird mortality and highlights how long-term wildlife disease studies can be used to identify anthropogenic threats to wildlife conservation and ecosystem health. In particular, mortality data for the past 30 yr suggest that biotoxins, viral, and bacterial diseases could have impacted >5 million aquatic birds. ?? Inter-Research 2007.

  3. Linking the evolution of habitat choice to ecosystem functioning: direct and indirect effects of pond-reproducing fire salamanders on aquatic-terrestrial subsidies.

    PubMed

    Reinhardt, Timm; Steinfartz, Sebastian; Paetzold, Achim; Weitere, Markus

    2013-09-01

    Shifts in life history traits and in the behaviour of species can potentially alter ecosystem functioning. The reproduction of the central European fire salamander (Salamandra salamandra), which usually deposits its larvae in first-order streams, in small pool and pond-like habitats, is an example of a recent local adaptation in this species. Here we aimed to quantify the direct and indirect effects of the predatory larvae on the aquatic food webs in the ponds and on the flux of matter between the ponds and adjacent terrestrial habitats. Our estimates are based on biomass data of the present pond fauna as well as on the analysis of stomach content data, growth rates and population dynamics of the salamander larvae in pond habitats. By their deposition of larvae in early spring, female fire salamanders import between 0.07 and 2.86 g dry mass m(-2) larval biomass into the ponds. Due to high mortality rates in the larval phase and the relatively small size at metamorphosis of the pond-adapted salamanders compared to stream-adapted ones, the biomass export of the metamorphosed salamanders clearly falls below the initial biomass import. Catastrophic events such as high water temperatures and low oxygen levels may even occasionally result in mass mortalities of salamander larvae and thus in a net 100 % import of the salamander biomass into the pond food webs. Indirect effects further accelerate this net import of matter into the aquatic habitat, e.g. the feeding of salamanders on aquatic insect larvae with the emergence of terrestrial adults-thus preventing export-and on terrestrial organisms that fall on the water surface (supporting import). This study demonstrates that the adaptation of salamanders to pond reproduction can alter food web linkages across ecosystem boundaries by enhancing the flux of materials and energy from terrestrial (i.e. forest) to the aquatic (i.e. pond) habitat. PMID:23358795

  4. Diets of aquatic birds reflect changes in the Lake Huron ecosystem

    USGS Publications Warehouse

    Hebert, Craig E.; Weseloh, D.V. Chip; Idrissi, Abode; Arts, Michael T.; Roseman, Edward F.

    2009-01-01

    Human activities have affected the Lake Huron ecosystem, in part, through alterations in the structure and function of its food webs. Insights into the nature of food web change and its ecological ramifications can be obtained through the monitoring of high trophic level predators such as aquatic birds. Often, food web change involves alterations in the relative abundance of constituent species and/or the introduction of new species (exotic invaders). Diet composition of aquatic birds is influenced, in part, by relative prey availability and therefore is a sensitive measure of food web structure. Using bird diet data to make inferences regarding food web change requires consistent measures of diet composition through time. This can be accomplished by measuring stable chemical and/or biochemical “ecological tracers” in archived avian samples. Such tracers provide insights into pathways of energy and nutrient transfer. In this study, we examine the utility of two groups of naturally-occurring intrinsic tracers (stable isotopes and fatty acids) to provide such information in a predatory seabird, the herring gull (Larus argentatus). Retrospective stable nitrogen and carbon isotope analysis of archived herring gull eggs identified declines in gull trophic position and shifts in food sources in Lake Huron over the last 25 years and changes in gull diet composition were inferred from egg fatty acid patterns. These independent groups of ecological tracers provided corroborating evidence of dietary change in this high trophic level predator. Gull dietary shifts were related to declines in prey fish abundance which suggests large-scale alterations to the Lake Huron ecosystem. Dietary shifts in herring gulls may be contributing to reductions in resources available for egg formation. Further research is required to evaluate how changes in resource availability may affect population sustainability in herring gulls and other waterbird species. Long-term biological monitoring

  5. A synthesis of the effects of pesticides on microbial persistence in aquatic ecosystems.

    PubMed

    Staley, Zachery R; Harwood, Valerie J; Rohr, Jason R

    2015-01-01

    Pesticides have a pervasive presence in aquatic ecosystems throughout the world. While pesticides are intended to control fungi, insects, and other pests, their mechanisms of action are often not specific enough to prevent unintended effects, such as on non-target microbial populations. Microorganisms, including algae and cyanobacteria, protozoa, aquatic fungi, and bacteria, form the basis of many food webs and are responsible for crucial aspects of biogeochemical cycling; therefore, the potential for pesticides to alter microbial community structures must be understood to preserve ecosystem services. This review examines studies that focused on direct population-level effects and indirect community-level effects of pesticides on microorganisms. Generally, insecticides, herbicides, and fungicides were found to have adverse direct effects on algal and fungal species. Insecticides and fungicides also had deleterious direct effects in the majority of studies examining protozoa species, although herbicides were found to have inconsistent direct effects on protozoans. Our synthesis revealed mixed or no direct effects on bacterial species among all pesticide categories, with results highly dependent on the target species, chemical, and concentration used in the study. Examination of community-level, indirect effects revealed that all pesticide categories had a tendency to reduce higher trophic levels, thereby diminishing top-down pressures and favoring lower trophic levels. Often, indirect effects exerted greater influence than direct effects. However, few studies have been conducted to specifically address community-level effects of pesticides on microorganisms, and further research is necessary to better understand and predict the net effects of pesticides on ecosystem health. PMID:26565685

  6. Spatial and temporal effects of olive mill wastewaters to stream macroinvertebrates and aquatic ecosystems status.

    PubMed

    Karaouzas, Ioannis; Skoulikidis, Nikolaos T; Giannakou, Urania; Albanis, Triantafyllos A

    2011-12-01

    Olive mill wastewater (OMW) is one of the major and most challenging organic pollutants in olive oil production countries. However, the knowledge about the in-situ effects of olive mill wastewaters to lotic ecosystems and their benthic organisms is very limited. To resolve this, eight sampling sites were selected upstream and downstream the outflow of several olive mills to assess the spatial and temporal effects of OMW to stream macroinvertebrates and to ecological status of stream ecosystems. Biotic (macroinvertebrates) and abiotic (physicochemical, hydromorphological) data were monitored for two years thus following the biennial cycle of olive growth and production and hydrological variation (drought-wet years). The results of this study revealed the spatial and temporal structural deterioration of the aquatic community due to OMW pollution with consequent reduction of the river capacity for reducing the effects of polluting substances through internal mechanisms of self-purification. OMW, even highly diluted, had dramatic impacts on the aquatic fauna and to the ecological status of the receiving stream ecosystems. The organic load of the wastewater expressed as BOD(5), COD and TSS, substrate contamination (sewage bacteria) and distance from the mill outlet, were the most important factors affecting macroinvertebrate assemblages while the typology (i.e. slope, altitude) and hydrology of the stream site (i.e. mountainous-lowland) and the intensity and volume of the wastewater were the most important determinants of self-purification processes. As OMW are usually being discharged in small size streams that are not considered in the Water Framework Directive 2000/60/EC, there is a need for including such systems into monitoring and assessment schemes as they may significantly contribute to the pollution load of the river basin. Furthermore, guidelines to manage these wastes through technologies that minimise their environmental impact and lead to a sustainable use

  7. Decadal changes in climate and ecosystems in the North Atlantic Ocean and adjacent seas

    NASA Astrophysics Data System (ADS)

    Beaugrand, Grégory

    2009-04-01

    Climate change is unambiguous and its effects are clearly detected in all functional units of the Earth system. This study presents new analyses of sea-surface temperature changes and show that climate change is affecting ecosystems of the North Atlantic. Changes are seen from phytoplankton to zooplankton to fish and are modifying the dominance of species and the structure, the diversity and the functioning of marine ecosystems. Changes also range from phenological to biogeographical shifts and have involved in some regions of the Atlantic abrupt ecosystem shifts. These alterations reflect a response of pelagic ecosystems to a warmer temperature regime. Mechanisms are complex because they are nonlinear exhibiting tipping points and varying in space and time. Sensitivity of organisms to temperature changes is high, implicating that a small temperature modification can have sustained ecosystem effects. Implications of these changes for biogeochemical cycles are discussed. Two observed changes detected in the North Sea that could have opposite effects on carbon cycle are discussed. Increase in phytoplankton, as inferred from the phytoplankton colour index derived from the Continuous Plankton Recorder (CPR) survey, has been detected in the North Sea. This pattern has been accompanied by a reduction in the abundance of the herbivorous species Calanus finmarchicus. This might have reduced the grazing pressure and increase diatomaceous 'fluff', therefore carbon export in the North Sea. Therefore, it could be argued that the biological carbon pump might increase in this region with sea warming. In the meantime, however, the mean size of organisms (calanoid copepods) has dropped. Such changes have implications for the turnover time of biogenic carbon in plankton organisms and the mean residence time of particulate carbon they produce. The system characterising the warmer period is more based on recycling and less on export. The increase in the minimum turnover time

  8. Using Remotely Sensed Data and Watershed and Hydrodynamic Models to Evaluate the Effects of Land Cover Land Use Change on Aquatic Ecosystems in Mobile Bay, AL

    NASA Technical Reports Server (NTRS)

    Al-Hamdan, Mohammad Z.; Estes, Maurice G., Jr.; Judd, Chaeli; Thom, Ron; Woodruff, Dana; Ellis, Jean T.; Quattrochi, Dale; Watson, Brian; Rodriquez, Hugo; Johnson, Hoyt

    2012-01-01

    Alabama coastal systems have been subjected to increasing pressure from a variety of activities including urban and rural development, shoreline modifications, industrial activities, and dredging of shipping and navigation channels. The impacts on coastal ecosystems are often observed through the use of indicator species. One such indicator species for aquatic ecosystem health is submerged aquatic vegetation (SAV). Watershed and hydrodynamic modeling has been performed to evaluate the impact of land cover land use (LCLU) change in the two counties surrounding Mobile Bay (Mobile and Baldwin) on SAV stressors and controlling factors (temperature, salinity, and sediment) in the Mobile Bay estuary. Watershed modeling using the Loading Simulation Package in C++ (LSPC) was performed for all watersheds contiguous to Mobile Bay for LCLU scenarios in 1948, 1992, 2001, and 2030. Remotely sensed Landsat-derived National Land Cover Data (NLCD) were used in the 1992 and 2001 simulations after having been reclassified to a common classification scheme. The Prescott Spatial Growth Model was used to project the 2030 LCLU scenario based on current trends. The LSPC model simulations provided output on changes in flow, temperature, and sediment for 22 discharge points into the estuary. These results were inputted in the Environmental Fluid Dynamics Computer Code (EFDC) hydrodynamic model to generate data on changes in temperature, salinity, and sediment on a grid throughout Mobile Bay and adjacent estuaries. The changes in the aquatic ecosystem were used to perform an ecological analysis to evaluate the impact on SAV habitat suitability. This is the key product benefiting the Mobile Bay coastal environmental managers that integrates the influences of temperature, salinity, and sediment due to LCLU driven flow changes with the restoration potential of SAVs. Data products and results are being integrated into NOAA s EcoWatch and Gulf of Mexico Data Atlas online systems for

  9. Using Remotely Sensed Data and Watershed and Hydrodynamic Models to Evaluate the Effects of Land Cover Land Use Change on Aquatic Ecosystems in Mobile Bay, AL

    NASA Astrophysics Data System (ADS)

    Al-Hamdan, M. Z.; Estes, M. G.; Judd, C.; Thom, R.; Woodruff, D.; Ellis, J. T.; Quattrochi, D.; Watson, B.; Rodriguez, H.; Johnson, H.

    2012-12-01

    Alabama coastal systems have been subjected to increasing pressure from a variety of activities including urban and rural development, shoreline modifications, industrial activities, and dredging of shipping and navigation channels. The impacts on coastal ecosystems are often observed through the use of indicator species. One such indicator species for aquatic ecosystem health is submerged aquatic vegetation (SAV). Watershed and hydrodynamic modeling has been performed to evaluate the impact of land cover land use (LCLU) change in the two counties surrounding Mobile Bay (Mobile and Baldwin) on SAV stressors and controlling factors (temperature, salinity, and sediment) in the Mobile Bay estuary. Watershed modeling using the Loading Simulation Package in C++ (LSPC) was performed for all watersheds contiguous to Mobile Bay for LCLU scenarios in 1948, 1992, 2001, and 2030. Remotely sensed Landsat-derived National Land Cover Data (NLCD) were used in the 1992 and 2001 simulations after having been reclassified to a common classification scheme. The Prescott Spatial Growth Model was used to project the 2030 LCLU scenario based on current trends. The LSPC model simulations provided output on changes in flow, temperature, and sediment for 22 discharge points into the estuary. These results were inputted in the Environmental Fluid Dynamics Computer Code (EFDC) hydrodynamic model to generate data on changes in temperature, salinity, and sediment on a grid throughout Mobile Bay and adjacent estuaries. The changes in the aquatic ecosystem were used to perform an ecological analysis to evaluate the impact on SAV habitat suitability. This is the key product benefiting the Mobile Bay coastal environmental managers that integrates the influences of temperature, salinity, and sediment due to LCLU driven flow changes with the restoration potential of SAVs. Data products and results are being integrated into NOAA's EcoWatch and Gulf of Mexico Data Atlas online systems for

  10. Editorial: Eutrophication and hypoxia and their impacts on the ecosystem of the Changjiang Estuary and adjacent coastal environment

    NASA Astrophysics Data System (ADS)

    Zhang, Jing; Xiao, Tian; Huang, Daji; Liu, Su Mei; Fang, Jianguang

    2016-02-01

    The Changjiang (Yangtze River) Estuary plays an important role in the land-ocean interactions of East Asia, particularly in regard to the fate of land-derived materials and their impact on marine ecosystems in the Northwest Pacific Ocean. The 12 papers included in this special issue describe results from the MEcoPAM Study, an IMBER-China project, which occurred in 2011-2015. This project used a multi-disciplinary approach to understand ecosystem function of the Changjiang Estuary in response to multiple stressors (i.e. combined external forcings). The results presented here show that human activities in the watersheds have greatly changed the flux and variation of dissolved and particulate materials from the river. Further interactions between the Changjiang Watersheds and the East China Sea can dramatically modify the pathways of biogeochemistry and food web dynamics of the estuary and adjacent coastal environment at seasonal and inter-annual scales.

  11. Primary production of coral ecosystems in the Vietnamese coastal and adjacent marine waters

    NASA Astrophysics Data System (ADS)

    Tac-An, Nguyen; Minh-Thu, Phan; Cherbadji, I. I.; Propp, M. V.; Odintsov, V. S.; Propp, L. H.

    2013-11-01

    Coral reef ecosystems in coastal waters and islands of Vietnam have high primary production. Average gross primary production (GPP) in coral reef waters was 0.39 g C m-2 day-1. GPP of corals ranged from 3.12 to 4.37 g C m-2 day-1. GPP of benthic microalgae in coral reefs ranged from 2 to 10 g C m-2 day-1. GPP of macro-algae was 2.34 g C m-2 day-1. Therefore, the total of GPP of whole coral reef ecosystems could reach 7.85 to 17.10 g C m-2 day-1. Almost all values of the ratio of photosynthesis to respiration in the water bodies are higher than 1, which means these regions are autotrophic systems. Wire variation of GPP in coral reefs was contributed by species abundance of coral and organisms, nutrient supports and environmental characteristics of coral ecosystems. Coral reefs play an important ecological role of biogeochemical cycling of nutrients in waters around the reefs. These results contribute valuable information for the protection, conservation and sustainable exploitation of the natural resources in coral reef ecosystems in Vietnam.

  12. Effects of wildfire on source-water quality and aquatic ecosystems, Colorado Front Range

    USGS Publications Warehouse

    Writer, Jeffrey H.; McClelskey, R. Blaine; Murphy, Sheila F.

    2012-01-01

    Watershed erosion can dramatically increase after wildfire, but limited research has evaluated the corresponding influence on source-water quality. This study evaluated the effects of the Fourmile Canyon wildfire (Colorado Front Range, USA) on source-water quality and aquatic ecosystems using high-frequency sampling. Dissolved organic carbon (DOC) and nutrient loads in stream water were evaluated for a one-year period during different types of runoff events, including spring snowmelt, and both frontal and summer convective storms. DOC export from the burned watershed did not increase relative to the unburned watershed during spring snowmelt, but substantial increases in DOC export were observed during summer convective storms. Elevated nutrient export from the burned watershed was observed during spring snowmelt and summer convective storms, which increased the primary productivity of stream biofilms. Wildfire effects on source-water quality were shown to be substantial following high-intensity storms, with the potential to affect drinking-water treatment processes.

  13. Introduction to the effects of wildland fire on aquatic ecosystems in the Western USA

    USGS Publications Warehouse

    Rieman, B.; Gresswell, Robert E.; Young, M.; Luce, C.

    2003-01-01

    The management of wildfire has long been controversial. The role of fire and fire-related management in terrestrial and aquatic ecosystems has become an important focus in recent years, but the general debate is not new. In his recent book, Stephen Pyne (2001)describes the political and scientific debate surrounding the creation of the U.S. Forest Service and the emergence of fire suppression as a central tenet of wildland management. Essentially, views in the first decade of the 20th century focused on fire as good or evil: a tool that might benefit other resources or interests (e.g. Indian burning) and mitigate larger more destructive fires, or a threat to the recruitment and productivity of newly designated forest reserves. The “great fires” in the Western USA in 1910 and the associated loss of human life and property largely forged the public and political will to suppress fire on a massive scale.

  14. Mapping critical loads of nitrogen deposition for aquatic ecosystems in the Rocky Mountains, USA

    USGS Publications Warehouse

    Nanus, Leora; Clow, David W.; Saros, Jasmine E.; Stephens, Verlin C.; Campbell, Donald H.

    2012-01-01

    Spatially explicit estimates of critical loads of nitrogen (N) deposition (CLNdep) for nutrient enrichment in aquatic ecosystems were developed for the Rocky Mountains, USA, using a geostatistical approach. The lowest CLNdep estimates (-1 yr-1) occurred in high-elevation basins with steep slopes, sparse vegetation, and abundance of exposed bedrock and talus. These areas often correspond with areas of high N deposition (>3 kg N ha-1 yr-1), resulting in CLNdep exceedances ≥1.5 ± 1 kg N ha-1 yr-1. CLNdep and CLNdep exceedances exhibit substantial spatial variability related to basin characteristics and are highly sensitive to the NO3- threshold at which ecological effects are thought to occur. Based on an NO3- threshold of 0.5 μmol L-1, N deposition exceeds CLNdep in 21 ± 8% of the study area; thus, broad areas of the Rocky Mountains may be impacted by excess N deposition, with greatest impacts at high elevations.

  15. Managing wastewater effluent to enhance aquatic receiving ecosystem productivity: a coastal lagoon in Western Australia.

    PubMed

    Machado, Daniel A; Imberger, Jörg

    2012-05-30

    Large amounts of waste are generated in urban centers that if properly managed could promote ecological services. In order to promote nutrient cycling and productivity without endangering aquatic ecosystems, management of wastewater treatment and effluent discharges to receiving waters must be assessed on a case-by-case basis. We applied this premise to examine a municipal wastewater treated effluent discharge in a shallow oligotrophic coastal lagoon in Western Australia. Three-dimensional hydrodynamic-ecological modeling (ELCOM-CAEDYM) was used to assess the reaction of ecosystem for effluent quality. Two scenarios were evaluated for the summer 2000-2001 period, the actual or "current" (conventional secondary treatment) and an "alternative" (involving substitution of biological nutrient removal by advanced treatment). The residence time of the simulated numerical domain averaged 8.4 ± 1.3 days. For the current scenario the model successfully estimated phytoplankton biomass, as chlorophyll-a concentration (Chl-a), that is within field-measured ranges and previously recorded levels. The model was able to reproduce nitrogen as the main limiting nutrient for primary production in the coastal ecosystem. Simulated surface Chl-a means were 0.26 (range 0.19-0.38) μg Chl-a/L for the current scenario and 0.37 (range 0.19-0.67) μg Chl-a/L for the alternative one. Comparison of the alternative scenario with field-measured Chl-a levels suggests moderate primary production increase (16-42%), within local historical variability. These results, suggest that such a scenario could be used, as part of a comprehensive wastewater management optimization strategy, to foster receiving ecosystem's productivity and related ecological services maintaining its oligotrophic state. PMID:22322127

  16. Trophic interactions determine the effects of drought on an aquatic ecosystem.

    PubMed

    Amundrud, Sarah L; Srivastava, Diane S

    2016-06-01

    Species interactions can be important mediators of community and ecosystem responses to environmental stressors. However, we still lack a mechanistic understanding of the indirect ecological effects of stress that arise via altered species interactions. To understand how species interactions will be altered by environmental stressors, we need to know if the species that are vulnerable to such stressors also have large impacts on the ecosystem. As predators often exhibit certain traits that are linked to a high vulnerability to stress (e.g., large body size, long generation time), as well as having large effects on communities (e.g., top-down trophic effects), predators may be particularly likely to mediate ecological effects of environmental stress. Other functional groups, like facilitators, are known to have large impacts on communities, but their vulnerability to perturbations remains undocumented. Here, we use aquatic insect communities in bromeliads to examine the indirect effects of an important stressor (drought) on community and ecosystem responses. In a microcosm experiment, we manipulated predatory and facilitative taxa under a range of experimental droughts, and quantified effects on community structure and ecosystem function. Drought, by adversely affecting the top predator, had indirect cascading effects on the entire food web, altering community composition and decomposition. We identified the likely pathway of how drought cascaded through the food web from the top-down as drought -->predator --> shredder --> decomposition. This stress-induced cascade depended on predators exhibiting both a strong vulnerability to drought and large impacts on prey (especially shredders), as well as shredders exhibiting high functional importance as decomposers. PMID:27459778

  17. Progestins as endocrine disrupters in aquatic ecosystems: Concentrations, effects and risk assessment.

    PubMed

    Fent, Karl

    2015-11-01

    In aquatic ecosystems, progesterone (P4) and synthetic progestins (gestagens) originate from excretion by humans and livestock. Synthetic progestins are used for contraception and as P4 for medical treatments as well. Despite significant use, their ecotoxicological implications are poorly understood. Only about 50% of the progestins in use have been analyzed for their environmental occurrence and effects in aquatic organisms. Here we critically summarize concentrations and effects of progestins in aquatic systems. P4 and progestins were mostly detected when analyzed for, and they occurred in the low ng/L range in wastewater and surface water. In animal farm waste and runoff, they reached up to several μg/L. P4 and synthetic progestins act through progesterone receptors but they also interact with other steroid hormone receptors. They act on the hypothalamus-pituitary-gonad axis, lead to oocyte maturation in female and sperm motility in male fish. Additionally, other pathways are affected as well, including the circadian rhythm. Effects of P4, mifepristone and eleven synthetic progestins have been studied in fish and a few compounds in frogs and mussels. Environmental risks may be associated with P4, dydrogesterone and medroxyprogesterone acetate, where transcriptional effects were found at highest environmental levels. Reproductive effects occurred at higher levels. However, norethindrone, levonorgestrel and norgestrel compromised reproduction at environmental (ng/L) concentrations. Thus, some of the progestins are very active endocrine disrupters. This review summarizes the current state of the art and highlights risks for fish. Further research is needed into environmental concentrations and effects of non-investigated progestins, unexplored modes of action, and the activity of mixtures of progestins and other steroids to fully assess their environmental risks. PMID:26276056

  18. Bioaccumulation of heavy metals in Mbaa River and the impact on aquatic ecosystem.

    PubMed

    Ajima, M N O; Nnodi, P C; Ogo, O A; Adaka, G S; Osuigwe, D I; Njoku, D C

    2015-12-01

    The bioaccumulation and toxic effects of heavy metals have caused ecological damage to aquatic ecosystem. In this study, concentration of heavy metals including zinc, lead, cadmium, iron, and copper were determined in the sediment and water as well as in the muscle, gill, and intestine of two fish species (Pelmatochromis guentheri and Pelmatochromis pulcher) of Mbaa River in Southeastern Nigeria. Samples were collected at three different spots from the river, and the level of heavy metals specified above were determined by atomic absorption spectroscopy (AAS) after a modified wet digestion process. The results indicated that sediment had the highest concentration of the heavy metals investigated while water had the lowest concentration. Fish tissues showed appreciable bioaccumulation of these metals as evidenced by a higher concentration profile when compared with that of water. Furthermore, the concentration of these heavy metals in water and their bioconcentration factor in the fish were above the recommended limit by WHO and FEPA, indicating that Mbaa River along Inyishi may not be suitable for drinking nor the fish safe for human consumption. The study also reveals the use of fish as bioindicator of aquatic environment. PMID:26597816

  19. Annual Cycle of Bacterial Secondary Production in Five Aquatic Habitats of the Okefenokee Swamp Ecosystem

    PubMed Central

    Murray, Robert E.; Hodson, Robert E.

    1985-01-01

    Rates of bacterial secondary production by free-living bacterioplankton in the Okefenokee Swamp are high and comparable to reported values for a wide variety of marine and freshwater ecosystems. Bacterial production in the water column of five aquatic habitats of the Okefenokee Swamp was substantial despite the acidic (pH 3.7), low-nutrient, peat-accumulating character of the environment. Incorporation of [3H]thymidine into cold-trichloroacetic acid-insoluble material ranged from 0.03 to 2.93 nmol liter−1 day−1) and corresponded to rates of bacterial secondary production of 3.4 to 342.2 μg of carbon liter−1 day−1 (mean, 87.8 μg of carbon liter−1 day−1). Bacterial production was strongly seasonal and appeared to be coupled to annual changes in temperature and primary production. Bacterial doubling times ranged from 5 h to 15 days and were fastest during the warm months of the year, when the biomass of aquatic macrophytes was high, and slowest during the winter, when the plant biomass was reduced. The high rates of bacterial turnover in Okefenokee waters suggest that bacterial growth is an important mechanism in the transformation of dissolved organic carbon into the nutrient-rich bacterial biomass which is utilized by microconsumers. PMID:16346757

  20. Characterizing the oxygen isotopic composition of phosphate sources to aquatic ecosystems.

    PubMed

    Young, Megan B; McLaughlin, Karen; Kendall, Carol; Stringfellow, William; Rollog, Mark; Elsbury, Katy; Donald, Elizabeth; Paytan, Adina

    2009-07-15

    The oxygen isotopic composition of dissolved inorganic phosphate (delta18Op) in many aquatic ecosystems is not in isotopic equilibrium with ambient water and, therefore, may reflect the source delta18Op. Identification of phosphate sources to water bodies is critical for designing best management practices for phosphate load reduction to control eutrophication. In order for delta18Op to be a useful tool for source tracking, the delta18Op of phosphate sources must be distinguishable from one another; however, the delta18Op of potential sources has not been well characterized. We measured the delta18Op of a variety of known phosphate sources, including fertilizers, semiprocessed phosphorite ore, particulate aerosols, detergents, leachates of vegetation, soil, animal feces, and wastewater treatment plant effluent. We found a considerable range of delta18Op, values (from +8.4 to +24.9 per thousand) for the various sources, and statistically significant differences were found between several of the source types. delta18Op measured in three different fresh water systems was generally not in equilibrium with ambient water. Although there is overlap in delta18Op values among the groups of samples, our results indicate that some sources are isotopically distinct and delta18Op can be used for identifying phosphate sources to aquatic systems. PMID:19708340

  1. PCB Food Web Dynamics Quantify Nutrient and Energy Flow in Aquatic Ecosystems.

    PubMed

    McLeod, Anne M; Paterson, Gordon; Drouillard, Ken G; Haffner, G Douglas

    2015-11-01

    Measuring in situ nutrient and energy flows in spatially and temporally complex aquatic ecosystems represents a major ecological challenge. Food web structure, energy and nutrient budgets are difficult to measure, and it is becoming more important to quantify both energy and nutrient flow to determine how food web processes and structure are being modified by multiple stressors. We propose that polychlorinated biphenyl (PCB) congeners represent an ideal tracer to quantify in situ energy and nutrient flow between trophic levels. Here, we demonstrate how an understanding of PCB congener bioaccumulation dynamics provides multiple direct measurements of energy and nutrient flow in aquatic food webs. To demonstrate this novel approach, we quantified nitrogen (N), phosphorus (P) and caloric turnover rates for Lake Huron lake trout, and reveal how these processes are regulated by both growth rate and fish life history. Although minimal nutrient recycling was observed in young growing fish, slow growing, older lake trout (>5 yr) recycled an average of 482 Tonnes·yr(-1) of N, 45 Tonnes·yr(-1) of P and assimilated 22 TJ yr(-1) of energy. Compared to total P loading rates of 590 Tonnes·yr(-1), the recycling of primarily bioavailable nutrients by fish plays an important role regulating the nutrient states of oligotrophic lakes. PMID:26437236

  2. Characterizing the oxygen isotopic composition of phosphate sources to aquatic ecosystems

    USGS Publications Warehouse

    Young, M.B.; McLaughlin, K.; Kendall, C.; Stringfellow, W.; Rollog, M.; Elsbury, K.; Donald, E.; Paytan, A.

    2009-01-01

    The oxygen isotopic composition of dissolved inorganic phosphate (δ18Op) in many aquatic ecosystems is not in isotopic equilibrium with ambient water and, therefore, may reflect the source δ18Op. Identification of phosphate sources to water bodies is critical for designing best management practices for phosphate load reduction to control eutrophication. In order for δ18O p to be a useful tool for source tracking, the δ18Op of phosphate sources must be distinguishable from one another; however, the δ18Op of potential sources has not been well characterized. We measured the δ18O p of a variety of known phosphate sources, including fertilizers, semiprocessed phosphorite ore, particulate aerosols, detergents, leachates of vegetation, soil, animal feces, and wastewater treatment plant effluent. We found a considerable range of δ18Op values (from +8.4 to +24.9‰) for the various sources, and statistically significant differences were found between several of the source types. δ18Op measured in three different fresh water systems was generally not in equilibrium with ambient water. Although there is overlap in δ18Op values among the groups of samples, our results indicate that some sources are isotopically distinct and δ18Op can be used for identifying phosphate sources to aquatic systems.

  3. Scaling hyporheic exchange and its influence on biogeochemical reactions in aquatic ecosystems

    USGS Publications Warehouse

    O'Connor, B.L.; Harvey, J.W.

    2008-01-01

    Hyporheic exchange and biogeochemical reactions are difficult to quantify because of the range in fluid-flow and sediment conditions inherent to streams, wetlands, and nearshore marine ecosystems. Field measurements of biogeochemical reactions in aquatic systems are impeded by the difficulty of measuring hyporheic flow simultaneously with chemical gradients in sediments. Simplified models of hyporheic exchange have been developed using Darcy's law generated by flow and bed topography at the sediment-water interface. However, many modes of transport are potentially involved (molecular diffusion, bioturbation, advection, shear, bed mobility, and turbulence) with even simple models being difficult to apply in complex natural systems characterized by variable sediment sizes and irregular bed geometries. In this study, we synthesize information from published hyporheic exchange investigations to develop a scaling relationship for estimating mass transfer in near-surface sediments across a range in fluid-flow and sediment conditions. Net hyporheic exchange was quantified using an effective diffusion coefficient (De) that integrates all of the various transport processes that occur simultaneously in sediments, and dimensional analysis was used to scale De to shear stress velocity, roughness height, and permeability that describe fluid-flow and sediment characteristics. We demonstrated the value of the derived scaling relationship by using it to quantify dissolved oxygen (DO) uptake rates on the basis of DO profiles in sediments and compared them to independent flux measurements. The results support a broad application of the De scaling relationship for quantifying coupled hyporheic exchange and biogeochemical reaction rates in streams and other aquatic ecosystems characterized by complex fluid-flow and sediment conditions.

  4. Solar energy development and aquatic ecosystems in the southwestern United States: potential impacts, mitigation, and research needs.

    PubMed

    Grippo, Mark; Hayse, John W; O'Connor, Ben L

    2015-01-01

    The cumulative impacts of utility-scale solar energy facilities on aquatic ecosystems in the Southwestern United States are of concern, considering the many existing regional anthropogenic stressors. We review the potential impacts of solar energy development on aquatic habitat and biota. The greatest potential for impacts is related to the loss, fragmentation, or prolonged drying of ephemeral water bodies and drainage networks resulting from the loss of desert washes within the construction footprint of the facility. Groundwater-dependent aquatic habitat may also be affected by operational groundwater withdrawal in the case of water-intensive solar technologies. Solar panels have also been found to attract aquatic insects and waterbirds, potentially resulting in mortality. Avoiding construction activity near perennial and intermittent surface waters is the primary means of reducing impacts on aquatic habitats, followed by measures to minimize erosion, sedimentation, and contaminant inputs into waterways. Currently, significant data gaps make solar facility impact assessment and mitigation more difficult. Examples include the need for more regional and site-specific studies of surface-groundwater connectivity, more detailed maps of regional stream networks and riparian vegetation corridors, as well as surveys of the aquatic communities inhabiting ephemeral streams. In addition, because they often lack regulatory protection, there is also a need to develop valuation criteria for ephemeral waters based on their ecological and hydrologic function within the landscape. By addressing these research needs, we can achieve the goal of greater reliance on solar energy, while at the same time minimizing impacts on desert ecosystems. PMID:25331641

  5. Solar Energy Development and Aquatic Ecosystems in the Southwestern United States: Potential Impacts, Mitigation, and Research Needs

    NASA Astrophysics Data System (ADS)

    Grippo, Mark; Hayse, John W.; O'Connor, Ben L.

    2015-01-01

    The cumulative impacts of utility-scale solar energy facilities on aquatic ecosystems in the Southwestern United States are of concern, considering the many existing regional anthropogenic stressors. We review the potential impacts of solar energy development on aquatic habitat and biota. The greatest potential for impacts is related to the loss, fragmentation, or prolonged drying of ephemeral water bodies and drainage networks resulting from the loss of desert washes within the construction footprint of the facility. Groundwater-dependent aquatic habitat may also be affected by operational groundwater withdrawal in the case of water-intensive solar technologies. Solar panels have also been found to attract aquatic insects and waterbirds, potentially resulting in mortality. Avoiding construction activity near perennial and intermittent surface waters is the primary means of reducing impacts on aquatic habitats, followed by measures to minimize erosion, sedimentation, and contaminant inputs into waterways. Currently, significant data gaps make solar facility impact assessment and mitigation more difficult. Examples include the need for more regional and site-specific studies of surface-groundwater connectivity, more detailed maps of regional stream networks and riparian vegetation corridors, as well as surveys of the aquatic communities inhabiting ephemeral streams. In addition, because they often lack regulatory protection, there is also a need to develop valuation criteria for ephemeral waters based on their ecological and hydrologic function within the landscape. By addressing these research needs, we can achieve the goal of greater reliance on solar energy, while at the same time minimizing impacts on desert ecosystems.

  6. Aquatic Ecosystems, Water Quality, and Global Change: Challenges of Conducting Multi-Stressor Vulnerability Assessments (Final Report)

    EPA Science Inventory

    This report investigates the issues and challenges associated with identifying, calculating, and mapping indicators of the relative vulnerability of water quality and aquatic ecosystems, across the United States, to the potential impacts of global change. Using a large set of en...

  7. Derivation of guideline values for gold (III) ion toxicity limits to protect aquatic ecosystems.

    PubMed

    Nam, Sun-Hwa; Lee, Woo-Mi; Shin, Yu-Jin; Yoon, Sung-Ji; Kim, Shin Woong; Kwak, Jin Il; An, Youn-Joo

    2014-01-01

    This study focused on estimating the toxicity values of various aquatic organisms exposed to gold (III) ion (Au(3+)), and to propose maximum guideline values for Au(3+) toxicity that protect the aquatic ecosystem. A comparative assessment of methods developed in Australia and New Zealand versus the European Community (EC) was conducted. The test species used in this study included two bacteria (Escherichia coli and Bacillus subtilis), one alga (Pseudokirchneriella subcapitata), one euglena (Euglena gracilis), three cladocerans (Daphnia magna, Moina macrocopa, and Simocephalus mixtus), and two fish (Danio rerio and Oryzias latipes). Au(3+) induced growth inhibition, mortality, immobilization, and/or developmental malformations in all test species, with responses being concentration-dependent. According to the moderate reliability method of Australia and New Zealand, 0.006 and 0.075 mg/L of guideline values for Au(3+) were obtained by dividing 0.33 and 4.46 mg/L of HC5 and HC50 species sensitivity distributions (SSD) with an FACR (Final Acute to Chronic Ratio) of 59.09. In contrast, the EC method uses an assessment factor (AF), with the 0.0006 mg/L guideline value for Au(3+) being divided with the 48-h EC50 value for 0.60 mg/L (the lowest toxicity value obtained from short term results) by an AF of 1000. The Au(3+) guideline value derived using an AF was more stringent than the SSD. We recommend that more toxicity data using various bioassays are required to develop more accurate ecological risk assessments. More chronic/long-term exposure studies on sensitive endpoints using additional fish species and invertebrates not included in the current dataset will be needed to use other derivation methods (e.g., US EPA and Canadian Type A) or the "High Reliability Method" from Australia/New Zealand. Such research would facilitate the establishment of guideline values for various pollutants that reflect the universal effects of various pollutants in aquatic ecosystems. To

  8. Chloroplast DNA Phylogeography Reveals Repeated Range Expansion in a Widespread Aquatic Herb Hippuris vulgaris in the Qinghai-Tibetan Plateau and Adjacent Areas

    PubMed Central

    Sun, Shan-Shan; Gituru, Robert Wahiti; Wang, Qing-Feng

    2013-01-01

    Background The Qinghai-Tibetan Plateau (QTP) is one of the most extensive habitats for alpine plants in the world. Climatic oscillations during the Quaternary ice age had a dramatic effect on species ranges on the QTP and the adjacent areas. However, how the distribution ranges of aquatic plant species shifted on the QTP in response to Quaternary climatic changes remains almost unknown. Methodology and Principal Findings We studied the phylogeography and demographic history of the widespread aquatic herb Hippuris vulgaris from the QTP and adjacent areas. Our sampling included 385 individuals from 47 natural populations of H. vulgaris. Using sequences from four chloroplast DNA (cpDNA) non-coding regions, we distinguished eight different cpDNA haplotypes. From the cpDNA variation in H. vulgaris, we found a very high level of population differentiation (GST = 0.819) but the phylogeographical structure remained obscure (NST = 0.853>GST = 0.819, P>0.05). Phylogenetic analyses revealed two main cpDNA haplotype lineages. The split between these two haplotype groups can be dated back to the mid-to-late Pleistocene (ca. 0.480 Myr). Mismatch distribution analyses showed that each of these had experienced a recent range expansion. These two expansions (ca. 0.12 and 0.17 Myr) might have begun from the different refugees before the Last Glacial Maximum (LGM). Conclusions/Significance This study initiates a research on the phylogeography of aquatic herbs in the QTP and for the first time sheds light on the response of an alpine aquatic seed plant species in the QTP to Quaternary climate oscillations. PMID:23565290

  9. Effects of anthropogenic nitrogen input on the aquatic food webs of river ecosystem in central Japan

    NASA Astrophysics Data System (ADS)

    Ohte, N.; Togashi, H.; Tokuchi, N.; Yoshimura, M.; Kato, Y.; Ishikawa, N. F.; Osaka, K.; Kondo, M.; Tayasu, I.

    2014-12-01

    To evaluate the impact of the anthropogenic nitrogen input to the river ecosystem, we conducted the monitoring on nutrient status of river waters and food web structures of aquatic organisms. Especially, changes of sources and concentration of nitrate (NO3-) in river water were focused to evaluate the impact of anthropogenic nitrogen loadings from agricultural and residential areas. Stable nitrogen isotope ratio (δ15N) of aquatic organisms has also intensively been monitored not only to describe their food web structure, but also to detect the influences of extraneous nitrogen inputs. Field samplings an observation campaigns were conducted in the Arida river watershed located in central part of Japan at four different seasons from September 2011 to October 2012. Five observation points were set from headwaters to the point just above the brackish waters starts. Water samples for chemical analysis were taken at the observation points for each campaign. Organisms including leaf litters, benthic algae, aquatic insects, crustacean, and fishes were sampled at each point quantitatively. Results of the riverine survey utilizing 5 regular sampling points showed that δ15N of nitrate (NO3-) increased from forested upstream (˜2 ‰) to the downstream (˜7 ‰) due to the sewage loads and fertilizer effluents from agricultural area. Correspondingly the δ15N of benthic algae and aquatic insects increased toward the downstream. This indicates that primary producers of each reach strongly relied on the local N sources and it was utilized effectively in their food web. Simulation using a GIS based mixing model considering the spatial distributions of human population density and fertilizer effluents revealed that strongest impacts of N inputs was originated from organic fertilizers applied to orchards in the middle to lower parts of catchment. Differences in δ15N between primary producers and predators were 6-7 ‰ similarly at all sampling points. Food web structural

  10. Carbon Sequestration and Energy Balance of Turf in the Denver Urban Ecosystem and Adjacent Tallgrass Prairie

    NASA Astrophysics Data System (ADS)

    Thienelt, T.; Anderson, D. E.; Powell, K. M.

    2012-12-01

    Urban ecosystems are currently characterized by rapid growth and are expected to continually expand. They represent an important driver of land use change. A significant component of urban ecosystems is lawns, potentially the single largest irrigated "crop" in the U.S. Between March and October of 2011 and 2012, eddy covariance measurements of net carbon dioxide exchange and evapotranspiration along with energy balance fluxes were conducted for an irrigated, fertilized lawn (rye-bluegrass-mix) in metropolitan Denver and for a nearby tallgrass prairie (big bluestem, switchgrass, cheatgrass, blue grama). Due to the semi-arid climate conditions of the Denver region, differences in management (i.e., irrigation and fertilization) are expected to have a discernible impact on ecosystem productivity and thus on carbon sequestration rates, evapotranspiration, and the partitioning of sensible and latent heat. Data for the 2011 season showed that cumulative evapotranspiration was approximately 600 mm for the urban lawn and 305 mm for the tallgrass prairie; cumulative carbon sequestration was calculated to be 172 and 85 g C/m2, respectively. Also, patterns of carbon exchange differed between the grasslands. In 2011, both sites showed daily net uptake of carbon starting in late May, but the urban lawn displayed greater diurnal variability as well as greater uptake rates in general, especially following fertilization in mid-June. In contrast, the trend of carbon uptake at the prairie site was occasionally reversed following strong convective precipitation events, resulting in a temporary net release of carbon. Preliminary data for the 2012 season (up to early July) indicated an earlier start of net carbon uptake and higher cumulative evapotranspiration for both locations, likely due to a warm spring. The continuing acquisition of data and investigation of these relations will help assess the potential impact of urban growth on regional carbon sequestration.

  11. Climate regulates alpine lake ice cover phenology and aquatic ecosystem structure

    NASA Astrophysics Data System (ADS)

    Preston, Daniel L.; Caine, Nel; McKnight, Diane M.; Williams, Mark W.; Hell, Katherina; Miller, Matthew P.; Hart, Sarah J.; Johnson, Pieter T. J.

    2016-05-01

    High-elevation aquatic ecosystems are highly vulnerable to climate change, yet relatively few records are available to characterize shifts in ecosystem structure or their underlying mechanisms. Using a long-term data set on seven alpine lakes (3126 to 3620 m) in Colorado, USA, we show that ice-off dates have shifted 7 days earlier over the past 33 years and that spring weather conditions—especially snowfall—drive yearly variation in ice-off timing. In the most well studied lake, earlier ice-off associated with increases in water residence times, thermal stratification, ion concentrations, dissolved nitrogen, pH, and chlorophyll a. Mechanistically, low spring snowfall and warm temperatures reduce summer stream flow (increasing lake residence times) but enhance melting of glacial and permafrost ice (increasing lake solute inputs). The observed links among hydrological, chemical, and biological responses to climate factors highlight the potential for major shifts in the functioning of alpine lakes due to forecasted climate change.

  12. Stable isotope analysis of energy dynamics in aquatic ecosystems suggests trophic shifts following severe wildfire

    NASA Astrophysics Data System (ADS)

    Martens, A. M.; Silins, U.; Bladon, K. D.; Williams, C.; Wagner, M. J.; Luchkow, E.

    2015-12-01

    Wildfire alters landscapes and can have significant impacts on stream ecosystems. The 2003 Lost Creek wildfire was one of the most severe on Alberta's eastern rocky mountain slopes, resulting in elevated sediment production and nutrient (phosphorus, nitrogen, and carbon) export in impacted streams. These resulted in increased algal productivity and macroinvertebrate abundance and diversity, and as a result, fish in watersheds draining wildfire affected catchments were larger than those in the same age class from reference (unburned) watersheds. In the present investigation, stable isotope analysis of C and N was utilized to evaluate ecosystem energy dynamics and describe trophic relationships in those watersheds. Aquatic invertebrates from burned catchments showed enrichment in δ13C and δ15N relative to algae suggesting a reliance on algae (autochthony) as a primary source of energy. Invertebrates from unburned systems were depleted in δ13C relative to algae indicating reliance on allochthonous or terrestrial primary energy sources. Preliminary analysis of δ15N in macroinvertebrates showed slight enrichment in burned catchments suggesting a trophic shift. More comprehensive macroinvertebrate sampling and identification has been conducted; isotopic analysis will provide greater resolution of how specific families within feeding guilds have been affected by wildfire. This will provide more robust insights into how wildfires may impact stream ecology in mountain environments.

  13. Climate regulates alpine lake ice cover phenology and aquatic ecosystem structure

    USGS Publications Warehouse

    Preston, Daniel L.; Caine, Nel; McKnight, Diane M.; Williams, Mark W.; Hell, Katherina; Miller, Matthew P.; Hart, Sarah J.; Johnson, Pieter T.J.

    2016-01-01

    High-elevation aquatic ecosystems are highly vulnerable to climate change, yet relatively few records are available to characterize shifts in ecosystem structure or their underlying mechanisms. Using a long-term dataset on seven alpine lakes (3126 to 3620 m) in Colorado, USA, we show that ice-off dates have shifted seven days earlier over the past 33 years and that spring weather conditions – especially snowfall – drive yearly variation in ice-off timing. In the most well-studied lake, earlier ice-off associated with increases in water residence times, thermal stratification, ion concentrations, dissolved nitrogen, pH, and chlorophyll-a. Mechanistically, low spring snowfall and warm temperatures reduce summer stream flow (increasing lake residence times) but enhance melting of glacial and permafrost ice (increasing lake solute inputs). The observed links among hydrological, chemical, and biological responses to climate factors highlight the potential for major shifts in the functioning of alpine lakes due to forecasted climate change.

  14. Bioassessment of contaminant transport and distribution in aquatic ecosystems by chemical analysis of burrowing mayflies (Hexagenia)

    USGS Publications Warehouse

    Steingraeber, M.T.; Wiener, J.G.

    1995-01-01

    Burrowing mayfly nymphs (Ephemeroptera) inhabit and ingest fine-grained sediments and detritus that may be enriched with metals and persistent organic compounds. The burrowing nymphs can externally adsorb and internally assimilate these contaminants, providing a link for the food chain transfer of potentially toxic substances from sediments to organisms in higher trophic levels. The emergent adults are short-lived and do not feed, thus their gut contents do not contribute greatly to their total contaminant burden. These characteristics make Hexagenia spp. And certain other burrowing mayflies useful for assessing ecosystem contamination. General protocols are presented for the collection, processing and analysis of emergent mayflies to assess the spatial distribution and bioaccumulation of sediment-associated contaminants in aquatic ecosystems. Two essential components of this bioassessment approach are a network of on-site volunteers with the materials and instructions needed to correctly collect and store samples and quality assurance procedures to estimate the accuracy of chemical analyses. The utility of this approach is demonstrated with an example of its application to the Upper Mississippi River (USA). Determination of cadmium, mercury and polychlorinated biphenyl congeners in emergent Hexagenia bilineata from a 1250 km reach of this river revealed (1) several source areas of contaminants and (2) distinct patterns in the bioaccumulation (and apparent sediment-associated transport) of each residue on both small and large spatial scales.

  15. Reviews and Syntheses: Effects of permafrost thaw on arctic aquatic ecosystems

    NASA Astrophysics Data System (ADS)

    Vonk, J. E.; Tank, S. E.; Bowden, W. B.; Laurion, I.; Vincent, W. F.; Alekseychik, P.; Amyot, M.; Billet, M. F.; Canário, J.; Cory, R. M.; Deshpande, B. N.; Helbig, M.; Jammet, M.; Karlsson, J.; Larouche, J.; MacMillan, G.; Rautio, M.; Anthony, K. M. Walter; Wickland, K. P.

    2015-07-01

    dissolved vs. particulate organic matter, coupled with the composition of that organic matter and the morphology and stratification characteristics of recipient systems will play an important role in determining the balance between the release of organic matter as greenhouse gases (CO2 and CH4), its burial in sediments, and its loss downstream. The magnitude of thaw impacts on northern aquatic ecosystems is increasing, as is the prevalence of thaw-impacted lakes and streams. There is therefore an urgent need to address the key gaps in understanding in order to predict the full effects of permafrost thaw on aquatic ecosystems throughout the Arctic, and their consequential feedbacks to climate.

  16. Reviews and syntheses: Effects of permafrost thaw on Arctic aquatic ecosystems

    NASA Astrophysics Data System (ADS)

    Vonk, J. E.; Tank, S. E.; Bowden, W. B.; Laurion, I.; Vincent, W. F.; Alekseychik, P.; Amyot, M.; Billet, M. F.; Canário, J.; Cory, R. M.; Deshpande, B. N.; Helbig, M.; Jammet, M.; Karlsson, J.; Larouche, J.; MacMillan, G.; Rautio, M.; Anthony, K. M. Walter; Wickland, K. P.

    2015-12-01

    of dissolved vs. particulate organic matter, coupled with the composition of that organic matter and the morphology and stratification characteristics of recipient systems will play an important role in determining the balance between the release of organic matter as greenhouse gases (CO2 and CH4), its burial in sediments, and its loss downstream. The magnitude of thaw impacts on northern aquatic ecosystems is increasing, as is the prevalence of thaw-impacted lakes and streams. There is therefore an urgent need to quantify how permafrost thaw is affecting aquatic ecosystems across diverse Arctic landscapes, and the implications of this change for further climate warming.

  17. Managing aquatic ecosystems and water resources under multiple stress--an introduction to the MARS project.

    PubMed

    Hering, Daniel; Carvalho, Laurence; Argillier, Christine; Beklioglu, Meryem; Borja, Angel; Cardoso, Ana Cristina; Duel, Harm; Ferreira, Teresa; Globevnik, Lidija; Hanganu, Jenica; Hellsten, Seppo; Jeppesen, Erik; Kodeš, Vit; Solheim, Anne Lyche; Nõges, Tiina; Ormerod, Steve; Panagopoulos, Yiannis; Schmutz, Stefan; Venohr, Markus; Birk, Sebastian

    2015-01-15

    Water resources globally are affected by a complex mixture of stressors resulting from a range of drivers, including urban and agricultural land use, hydropower generation and climate change. Understanding how stressors interfere and impact upon ecological status and ecosystem services is essential for developing effective River Basin Management Plans and shaping future environmental policy. This paper details the nature of these problems for Europe's water resources and the need to find solutions at a range of spatial scales. In terms of the latter, we describe the aims and approaches of the EU-funded project MARS (Managing Aquatic ecosystems and water Resources under multiple Stress) and the conceptual and analytical framework that it is adopting to provide this knowledge, understanding and tools needed to address multiple stressors. MARS is operating at three scales: At the water body scale, the mechanistic understanding of stressor interactions and their impact upon water resources, ecological status and ecosystem services will be examined through multi-factorial experiments and the analysis of long time-series. At the river basin scale, modelling and empirical approaches will be adopted to characterise relationships between multiple stressors and ecological responses, functions, services and water resources. The effects of future land use and mitigation scenarios in 16 European river basins will be assessed. At the European scale, large-scale spatial analysis will be carried out to identify the relationships amongst stress intensity, ecological status and service provision, with a special focus on large transboundary rivers, lakes and fish. The project will support managers and policy makers in the practical implementation of the Water Framework Directive (WFD), of related legislation and of the Blueprint to Safeguard Europe's Water Resources by advising the 3rd River Basin Management Planning cycle, the revision of the WFD and by developing new tools for

  18. Threats and stressors to the health of the ecosystems of Lakes Mead and Mohave: Chapter 6 in A synthesis of aquatic science for management of Lakes Mead and Mohave

    USGS Publications Warehouse

    Rosen, Michael R.; Goodbred, Steven L.; Wong, Wai Hing; Patiño, Reynaldo; Turner, Kent; Palmer, Craig J.; Roefer, Peggy

    2012-01-01

    Ecosystem impacts from visitor activities or natural environmental change are important concerns in all units of the National Park system. Possible impacts to aquatic ecosystems at Lake Mead National Recreation Area (LMNRA) are of particular concern because of the designation of Lakes Mead and Mohave as critical habitat for the federally listed endangered razorback sucker (Xyrauchen texanus), the significance of the sport fishery, and the regional importance of its habitats to more than 90 documented species of waterbirds. Potential threats to shoreline habitats are of concern not only for their ecosystem values but also for maintaining the recreational setting. Many areas adjacent to the shorelines of Lakes Mead and Mohave are designated wilderness areas. For purposes of this document, stressors are any chemical, biological, or physical agent that has a detrimental effect on aquatic ecosystems at the organism, population, or community level. Human-made stressors at Lakes Mead and Mohave include direct effects of recreation on the lakes, like boating and fishing, as well as indirect effects of activities away from the lakes, such as growing population and increasing urbanization. Common natural environmental stressors include extended changes in climate (precipitation or temperature), or the erosion, transport, and loading of chemical constituents in rocks and sediments to aquatic environments. Human activity also can exacerbate natural stressors in a variety of ways.

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    operating with initial horizontal flow and continuous vertical circulation through aeration apparatus. Along the flow path several different bio-modules are applied, the sequence consists of aerobic and anaerobic stages, as well as biomass preservation section and fine grain filtration. The pilot biofilter facility was built during the summer of 2009; the influent consisted of domestic wastewater (of the adjacent Ariel University dormitories) and also synthetic aquatic solutions equivalent to urban, industrial, and roads runoff effluents. The biofilter operation evaluation demonstrated significant decrease in pollution loads, including organic, salts and pathogens. The facility's efficiency reached approximately 90% reduction or more, allowing the release of treated runoff without limitation to natural fluvial ecosystems (according to the required regulations). The present stage in the project is implementation of the method and process by application of a full scale pilot facility at a joint between an anthropogenic drainage network, consisting of urban, industrial and motorway runoff collection systems and a typical natural Samaritan fluvial ecosystem. The purpose of the system is to treat these anthropogenic effluents prior to their release into the stream and by that to prevent the negative environmental above mentioned effects.

  20. A multi-stable isotope framework to understand eutrophication in aquatic ecosystems.

    PubMed

    Gooddy, Daren C; Lapworth, Dan J; Bennett, Sarah A; Heaton, Tim H E; Williams, Peter J; Surridge, Ben W J

    2016-01-01

    Eutrophication is a globally significant challenge facing aquatic ecosystems, associated with human induced enrichment of these ecosystems with nitrogen (N) and phosphorus (P). However, the limited availability of inherent labels for P and N has constrained understanding of the triggers for eutrophication in natural ecosystems and appropriate targeting of management responses. This paper proposes and evaluates a new multi-stable isotope framework that offers inherent labels to track biogeochemical reactions governing both P and N in natural ecosystems. The framework couples highly novel analysis of the oxygen isotope composition of phosphate (δ(18)OPO4) with dual isotope analysis of oxygen and N within nitrate (δ(15)NNO3, δ(18)ONO3) and with stable N isotope analysis in ammonium (δ(15)NNH4). The River Beult in England is used as an exemplar system for initial evaluation of this framework. Our data demonstrate the potential to use stable isotope labels to track the input and downstream fate of nutrients from point sources, on the basis of isotopic differentiation for both P and N between river water and waste water treatment work effluent (mean difference = +1.7‰ for δ(18)OPO4; +15.5‰ for δ(15)NNH4 (under high flow); +7.3‰ for δ(18)ONO3 and +4.4‰ for δ(15)NNO3). Stable isotope data reveal nutrient inputs to the river upstream of the waste water treatment works that are consistent with partially denitrified sewage or livestock sources of nitrate (δ(15)NNO3 range = +11.5 to +13.1‰) and with agricultural sources of phosphate (δ(18)OPO4 range = +16.6 to +19.0‰). The importance of abiotic and metabolic processes for the in-river fate of N and P are also explored through the stable isotope framework. Microbial uptake of ammonium to meet metabolic demand for N is suggested by substantial enrichment of δ(15)NNH4 (by 10.2‰ over a 100 m reach) under summer low flow conditions. Whilst the concentration of both nitrate and phosphate

  1. Assessing Sources of Stress to Aquatic Ecosystems: Using Biomarkers and Bioindicators to Characterize Exodure-Response Profiles of Anthropogenic Activities

    SciTech Connect

    Adams, S.M.

    1999-03-29

    Establishing causal relationships between sources of environmental stressors and aquatic ecosystem health if difficult because of the many biotic and abiotic factors which can influence or modify responses of biological systems to stress, the orders of magnitude involved in extrapolation over both spatial and temporal scales, and compensatory mechanisms such as density-dependent responses that operate in populations. To address the problem of establishing causality between stressors and effects on aquatic systems, a diagnostic approach, based on exposure-response profiles for various anthropogenic activities, was developed to help identify sources of stress responsible for effects on aquatic systems at ecological significant levels of biological organization (individual, population, community). To generate these exposure-effects profiles, biomarkers of exposure were plotted against bioindicators of corresponding effects for several major anthropogenic activities including petrochemical , pulp and paper, domestic sewage, mining operations, land-development activities, and agricultural activities. Biomarkers of exposure to environmental stressors varied depending on the type of anthropogenic activity involved. Bioindicator effects, however, including histopathological lesions, bioenergetic status, individual growth, reproductive impairment, and community-level responses were similar among many of the major anthropogenic activities. This approach is valuable to help identify and diagnose sources of stressors in environments impacted by multiple stressors. By identifying the types and sources of environmental stressors, aquatic ecosystems can be more effectively protected and managed to maintain acceptable levels of environmental quality and ecosystem fitness.

  2. Bottom-up nutrient and top-down fish impacts on insect-mediated mercury flux from aquatic ecosystems.

    PubMed

    Jones, Taylor A; Chumchal, Matthew M; Drenner, Ray W; Timmins, Gabrielle N; Nowlin, Weston H

    2013-03-01

    Methyl mercury (MeHg) is one of the most hazardous contaminants in the environment, adversely affecting the health of wildlife and humans. Recent studies have demonstrated that aquatic insects biotransport MeHg and other contaminants to terrestrial consumers, but the factors that regulate the flux of MeHg out of aquatic ecosystems via emergent insects have not been studied. The authors used experimental mesocosms to test the hypothesis that insect emergence and the associated flux of MeHg from aquatic to terrestrial ecosystems is affected by both bottom-up nutrient effects and top-down fish consumer effects. In the present study, nutrient addition led to an increase in MeHg flux primarily by enhancing the biomass of emerging insects whose tissues were contaminated with MeHg, whereas fish decreased MeHg flux primarily by reducing the biomass of emerging insects. Furthermore, the authors found that these factors are interdependent such that the effects of nutrients are more pronounced when fish are absent, and the effects of fish are more pronounced when nutrient concentrations are high. The present study is the first to demonstrate that the flux of MeHg from aquatic to terrestrial ecosystems is strongly enhanced by bottom-up nutrient effects and diminished by top-down consumer effects. PMID:23180684

  3. Observations of tidal flux between a submersed aquatic plant stand and the adjacent channel in the Potomac River near Washington, D.C.

    USGS Publications Warehouse

    Rybicki, N.B.; Jenter, H.L.; Carter, V.; Baltzer, R.A.; Turtora, M.

    1997-01-01

    Dye injection studies and direct velocity and water-level measurements were made in macrophyte stands and adjacent channels in order to observe the effects of the macrophyte stand on flow and mass exchange in the tidal Potomac River. During the summer, dense stands of submersed aquatic plants cover most shoals <2 m deep. Continuous summertime water-level records within a submersed aquatic plant stand and in the adjacent channel revealed time-varying gradients in water-surface elevation between the two areas. Water-level gradients are created by differing rates of tidal water-level change in vegetated and unvegetated areas. Results were consistent with the idea that on a rising tide the water was slower to enter a macrophyte stand, and on a falling tide it was slower to leave it. Differences in water elevation between the stand and the open channel generated components of velocity in the stand that were at right angles to the line of flow in the channel. Seasonal differences in flow speed and direction over the shoals indicate substantial differences in resistance to flow as a result of the vegetation.

  4. Land use Controls on Water Quality and Aquatic Ecosystems in the Andean Amazon, Peru

    NASA Astrophysics Data System (ADS)

    Waggoner, L. A.; McClain, M. E.

    2007-05-01

    Agro-pastoral systems are replacing many of the tropical forests in the world, and much of this deforestation occurs in watersheds where people's livelihoods rely directly on water and aquatic resources in local streams and rivers. We examined relationships between land use and aquatic ecosystems in 34 catchments exhibiting a gradient of land use disturbance and human settlement in the Andean Amazon of Peru. Our research objectives were to 1) classify and characterize watershed land use and physical properties using remotely sensed data, 2) characterize the physical, biological and chemical conditions of streams 3) examine relationships between land use and water quality parameters at 3 scales: watershed, riparian and reach habitat and 4) translate research findings into management strategies that minimize disturbance and maximize ecosystem services. Primary forest was the dominant cover (68%) across the catchments, and the remaining study area was composed of: mixed forest (11.5%), grassland (10.75%) cropland (9.17%) and bare rock (0.02%). Among watersheds, forest cover ranged from 14% to 100%, mixed forest ranged from 0% to 26%, grassland ranged from 0% to 45% and cropland ranged from 0% to 26%. Physical habitat index scores ranged from 12.80 (very impaired) to 29.50 (reference conditions). Although nitrogen, phosphorous, dissolved organic carbon (DOC), pH, electric conductivity, and dissolved oxygen (DO), varied across sites, total concentrations remained within acceptable levels. Simpson's diversity and Family Biotic Index (FBI) were calculated for macroinvertebrates collected at each site; Simpson's diversity ranged from 0.24 to 0.95 and FBI ranged from 1.97 (excellent) to 7.49 (fairly poor). Forest cover at the watershed scale was the best explanatory variable and was positively correlated with inorganic phosphate (0.50), DO (0.90) and Simpson's diversity (0.46) and negatively correlated with organic phosphate (- 0.64), DOC (-0.75), water temperature (-0

  5. The environmental costs of mountaintop mining valley fill operations for aquatic ecosystems of the Central Appalachians.

    PubMed

    Bernhardt, Emily S; Palmer, Margaret A

    2011-03-01

    Southern Appalachian forests are recognized as a biodiversity hot spot of global significance, particularly for endemic aquatic salamanders and mussels. The dominant driver of land-cover and land-use change in this region is surface mining, with an ever-increasing proportion occurring as mountaintop mining with valley fill operations (MTVF). In MTVF, seams of coal are exposed using explosives, and the resulting noncoal overburden is pushed into adjacent valleys to facilitate coal extraction. To date, MTVF throughout the Appalachians have converted 1.1 million hectares of forest to surface mines and buried more than 2,000 km of stream channel beneath mining overburden. The impacts of these lost forests and buried streams are propagated throughout the river networks of the region as the resulting sediment and chemical pollutants are transmitted downstream. There is, to date, no evidence to suggest that the extensive chemical and hydrologic alterations of streams by MTVF can be offset or reversed by currently required reclamation and mitigation practices. PMID:21449964

  6. Transgenic Bacillus thuringiensis (Bt) rice is safer to aquatic ecosystems than its non-transgenic counterpart.

    PubMed

    Li, Guangsheng; Wang, Yongmo; Liu, Biao; Zhang, Guoan

    2014-01-01

    Rice lines genetically modified with the crystal toxin genes from Bacillus thuringiensis (Bt) have experienced rapid development, with biosafety certificates for two Bt rice lines issued in 2009. There has still been no commercial release of these lines yet due to public concerns about human health and environmental risks. Some studies confirmed that Bt rice was as safe as conventional rice to non-target organisms when pesticides were not applied, however, pesticides are still required in Bt rice to control non-lepidopteran pests. In this study, we assessed the environmental effects of two Bt rice lines expressing either the cry1Ab/1Ac or cry2A genes, respectively, by using zooplanktons as indicator species under normal field management practices using pesticides when required. In the whole rice growing season, non-Bt rice was sprayed 5 times while Bt rice was sprayed 2 times, which ensured both rice achieved a normal yield. Field investigations showed that rice type (Bt and non-Bt) significantly influenced zooplankton abundance and diversity, which were up to 95% and 80% lower in non-Bt rice fields than Bt rice fields. Laboratory rearing showed that water from non-Bt rice fields was significantly less suitable for the survival and reproduction of Daphnia magna and Paramecium caudatum in comparison with water from Bt rice fields. Higher pesticide residues were detected in the water from non-Bt than Bt rice fields, accounting for the bad performance of zooplankton in non-Bt field water. Our results demonstrate that Bt rice is safer to aquatic ecosystems than non-Bt rice, and its commercialization will be beneficial for biodiversity restoration in rice-based ecosystems. PMID:25105299

  7. Transgenic Bacillus thuringiensis (Bt) Rice Is Safer to Aquatic Ecosystems than Its Non-Transgenic Counterpart

    PubMed Central

    Li, Guangsheng; Wang, Yongmo; Liu, Biao; Zhang, Guoan

    2014-01-01

    Rice lines genetically modified with the crystal toxin genes from Bacillus thuringiensis (Bt) have experienced rapid development, with biosafety certificates for two Bt rice lines issued in 2009. There has still been no commercial release of these lines yet due to public concerns about human health and environmental risks. Some studies confirmed that Bt rice was as safe as conventional rice to non-target organisms when pesticides were not applied, however, pesticides are still required in Bt rice to control non-lepidopteran pests. In this study, we assessed the environmental effects of two Bt rice lines expressing either the cry1Ab/1Ac or cry2A genes, respectively, by using zooplanktons as indicator species under normal field management practices using pesticides when required. In the whole rice growing season, non-Bt rice was sprayed 5 times while Bt rice was sprayed 2 times, which ensured both rice achieved a normal yield. Field investigations showed that rice type (Bt and non-Bt) significantly influenced zooplankton abundance and diversity, which were up to 95% and 80% lower in non-Bt rice fields than Bt rice fields. Laboratory rearing showed that water from non-Bt rice fields was significantly less suitable for the survival and reproduction of Daphnia magna and Paramecium caudatum in comparison with water from Bt rice fields. Higher pesticide residues were detected in the water from non-Bt than Bt rice fields, accounting for the bad performance of zooplankton in non-Bt field water. Our results demonstrate that Bt rice is safer to aquatic ecosystems than non-Bt rice, and its commercialization will be beneficial for biodiversity restoration in rice-based ecosystems. PMID:25105299

  8. Spatial Variation of Atmospheric Nitrogen Deposition and Estimated Critical Loads for Aquatic Ecosystems in the Greater Yellowstone Area

    NASA Astrophysics Data System (ADS)

    Nanus, L.; McMurray, J. A.; Clow, D. W.; Saros, J. E.; Blett, T.

    2015-12-01

    Aquatic ecosystems at high-elevations in the Greater Yellowstone Area (GYA) are sensitive to the effects of atmospheric nitrogen (N) deposition. Current and historic N deposition has impacted aquatic ecosystems in the GYA and N deposition is increasing in many areas. Anticipated changes in atmospheric emissions may further affect these sensitive ecosystems. Understanding the spatial variation in atmospheric N deposition is needed to develop estimates of air pollution critical loads for aquatic ecosystems in complex terrain. For the GYA, high resolution (400 meter) maps were developed for 1993-2014 to identify areas of high loading of mean annual Total N deposition (wet + dry) and wet deposition of inorganic N (nitrate and ammonium). Total N deposition estimates in the GYA range from ≤ 1.4 to 7.5 kg N ha-1 yr-1 and show greater variability than inorganic N deposition. Spatially explicit estimates of critical loads of N deposition (CLNdep) for nutrient enrichment in aquatic ecosystems were developed using a geostatistical approach. CLNdep in the GYA ranges from less than 1.5 kg N ha-1 yr-1 to over 10 kg N ha-1 yr-1 and variability is controlled by differences in basin characteristics. The lowest CLNdep estimates occurred in high-elevation basins with steep slopes, sparse vegetation, and exposed bedrock, including areas within GYA Wilderness boundaries. These areas often have high inorganic N deposition (>3 kg N ha-1 yr-1), resulting in CLNdep exceedances greater than 1.5 kg N ha-1 yr-1. The N deposition maps were used to identify CLNdep exceedances for aquatic ecosystems, and to explore scale dependence and boundary issues related to estimating CLNdep. Based on a NO3- threshold of 1.0 μmol L-1, inorganic N deposition exceeds CLNdep in 12% of the GYA, and Total N deposition is in exceedance for 23% of the GYA. These maps can be used to help identify and protect sensitive ecosystems that may be impacted by excess N deposition in the GYA.

  9. Structural and functional effects of herbicides on non-target organisms in aquatic ecosystems with an emphasis on atrazine

    USGS Publications Warehouse

    Fairchild, James

    2011-01-01

    Agricultural production accounts for approximately 90% of herbicide use in the U.S. (Kiely et al., 2004). Gianessi and Reigner (2007) indicated that herbicides are routinely used on more than 90% of the area designated for large commercial crops including corn, soybeans, cotton, sugar beets, peanuts, and rice. Increased farm mechanization, technological advancements in production of inexpensive sources of inorganic nitrogen fertilizer (e.g., anhydrous ammonia), and conversion of forest, grassland, and wetland habitats to cropland has led to a tremendous increase in global food production over the past half-century. Herbicides have augmented advances in large-scale agricultural systems and have largely replaced mechanical and hand-weeding control mechanisms (Gianessi and Reigner, 2007). The wide-spread use of herbicides in agriculture has resulted in frequent chemical detections in surface and groundwaters (Gilliom, 2007). The majority of herbicides used are highly water soluble and are therefore prone to runoff from terrestrial environments. In additon, spray drift and atmospheric deposition can contribute to herbicide contamination of aquatic environments. Lastly, selected herbicides are deliberately applied to aquatic environments for controlling nuisance aquatic vegetation. Although aquatic herbicide exposure has been widely documented, these exposures are not necessarily related to adverse non-target ecological effects on natural communities in aquatic environments. This chapter evaluates the potential for effects of herbicides on the structure and function of aquatic envrionments at the population, community, and ecosystem levels of biological organization. In this manuscript I examine several critical aspects of the subject matter area: primary herbicides in use and chemical modes of action; the regulatory process used for registration and risk assessment of herbicides; data regarding non-target risks and the relative sensitivity of aquatic plants

  10. Ecological risk assessment of zinc from stormwater runoff to an aquatic ecosystem.

    PubMed

    Brix, Kevin V; Keithly, James; Santore, Robert C; DeForest, David K; Tobiason, Scott

    2010-03-15

    Zinc (Zn) risks from stormwater runoff to an aquatic ecosystem were studied. Monitoring data on waterborne, porewater, and sediment Zn concentrations collected at 20 stations throughout a stormwater collection/detention facility consisting of forested wetlands, a retention pond and first order stream were used to conduct the assessment. Bioavailability in the water column was estimated using biotic ligand models for invertebrates and fish while bioavailability in the sediment was assessed using acid volatile sulfide-simultaneously extracted metal (AVS-SEM). The screening level assessment indicated no significant risks were posed to benthic organisms from Zn concentrations in sediments and pore water. As would be expected for stormwater, Zn concentrations were temporally quite variable within a storm event, varying by factors of 2 to 4. Overall, probabilistic assessment indicated low (5-10% of species affected) to negligible risks in the system, especially at the discharge to the first order stream. Moderate to high risks (10-50% of species affected) were identified at sampling locations most upgradient in the collection system. The largest uncertainty with the assessment is associated with how best to estimate chronic exposure/risks from time-varying exposure concentrations. Further research on pulse exposure metal toxicity is clearly needed to assess stormwater impacts on the environment. PMID:20035970

  11. A methodological approach to characterize the resilience of aquatic ecosystems with application to Lake Annecy, France

    NASA Astrophysics Data System (ADS)

    Pinault, J.-L.; Berthier, F.

    2007-01-01

    We propose a methodological approach to characterize the resilience of aquatic ecosystems with respect to the evolution of environmental parameters as well as their aptitude to adapt to forcings. This method that is applied to Lake Annecy, France, proceeds in three stages. First, according to the depth, variations of physicochemical parameters versus time are separated into three components related to (1) energy transfer through the surface of the lake, (2) the flow of rivers and springs that feed the lake, and (3) long-term evolution of the benthic zone as a consequence of mineral and organic matter loads. Second, dynamics of the lake are deduced by analyzing the physicochemical parameter components related to the three boundary conditions. Third, a stochastic process associated with the transfer models aims to characterize the resilience of the lakes according to forcings. For Lake Annecy, whose dynamics are representative of oligotrophic stratified lakes controlled by decarbonation processes where turnover and mixing occurring once a year in winter, the major consequence is the impoverishment of dissolved oxygen in deep water in autumn due to a temperature increase of the surface water in summer. The simulation raises relevant questions about whether a connection exists between physicochemical parameters and global warming, which should not induce harmful consequences on water quality and biodiversity in deep water. This methodological approach is general since it does not use any physical conceptual model to predict the hydrosystem behavior but uses directly observed data.

  12. Aquatic ecotoxicology: from the ecosystem to the cellular and molecular levels.

    PubMed Central

    Boudou, A; Ribeyre, F

    1997-01-01

    This review of aquatic ecotoxicology is presented in three parts. First, we discuss the fundamental concepts and stress the importance of its ecological basis and the complexity and diversity of the field of investigation, which result from actions and interactions between the physicochemical characteristics of the biotopes, the structural and functional properties of the living organisms, and the contamination modalities. Ecotoxicological mechanisms, regardless of the level of biological complexity, primarily depend on the bioavailability of the toxic products. Numerous processes control the chemical fate of contaminants in the water column and/or sediment compartments; accessibility to the biological barriers that separate the organisms from their surrounding medium depends directly on bioavailability. Second, we review the principal methodologies of the field, from in situ studies at the ecosystem/ecocomplex level to bioassays or single species tests. Third, we focus on mercury, selected as a reference contaminant, in order to illustrate the main ecotoxicological concepts, the complementarity between field and laboratory studies, and the indispensable multidisciplinarity of the approaches. PMID:9114275

  13. A methodology for assessing the impact of mutagens on aquatic ecosystems. Final report

    SciTech Connect

    Knezovich, J.P.; Martinelli, R.E.

    1995-03-01

    Assessments of impacts of hazardous agents (i.e., chemical and physical mutagens) on human health have focused on defining the effects of chronic exposure on individuals, with cancer being the main effect of concern. In contrast, impacts on ecosystems have traditionally been gauged by the assessment of near-term organism mortality, which is clearly not a useful endpoint for assessing the long-term effects of chronic exposures. Impacts on individual organisms that affect the long-term survival of populations are much more important but are also more difficult to define. Therefore, methods that provide accurate measures of sub-lethal effects that are linked to population survival are required so that accurate assessments of environmental damage can be made and remediation efforts, if required, can be initiated. Radioactive substances have entered aquatic environments as a result of research and production activities, intentional disposal, and accidental discharges. At several DOE sites, surface waters and sediments are contaminated with radioactive and mutagenic materials. The accident at the Chernobyl power station in the former Soviet Union (FSU) has resulted in the contamination of biota present in the Kiev Reservoir. This documents presents a methodology which addresses the effects of a direct-acting mutagen (radiation) on aquantic organisms by applying sensitive techniques for assessing damage to genetic material.

  14. The combination of different carbon sources enhances bacterial growth efficiency in aquatic ecosystems.

    PubMed

    Fonte, Ellen S; Amado, André M; Meirelles-Pereira, Frederico; Esteves, Francisco A; Rosado, Alexandre S; Farjalla, Vinicius F

    2013-11-01

    The dissolved organic carbon (DOC) pool is composed of several organic carbon compounds from different carbon sources. Each of these sources may support different bacterial growth rates, but few studies have specifically analyzed the effects of the combination of different carbon sources on bacterial metabolism. In this study, we evaluated the response of several metabolic parameters, including bacterial biomass production (BP), bacterial respiration (BR), bacterial growth efficiency (BGE), and bacterial community structure, on the presence of three DOC sources alone and in combination. We hypothesized that the mixture of different DOC sources would increase the efficiency of carbon use by bacteria (BGE). We established a full-factorial substitutive design (seven treatments) in which the effects of the number and identity of DOC sources on bacterial metabolism were evaluated. We calculated the expected metabolic rates of the combined DOC treatments based on the single-DOC treatments and observed a positive interaction on BP, a negative interaction on BR, and, consequently, a positive interaction on BGE for the combinations. The bacterial community composition appeared to have a minor impact on differences in bacterial metabolism among the treatments. Our data indicate that mixtures of DOC sources result in a more efficient biological use of carbon. This study provides strong evidence that the mixture of different DOC sources is a key factor affecting the role of bacteria in the carbon flux of aquatic ecosystems. PMID:23963223

  15. Scaling relationships among drivers of aquatic respiration from the smallest to the largest freshwater ecosystems

    USGS Publications Warehouse

    Hall, Ed K; Schoolmaster, Donald; Amado, A.M; Stets, Edward G.; Lennon, J.T.; Domaine, L.; Cotner, J.B.

    2016-01-01

    To address how various environmental parameters control or constrain planktonic respiration (PR), we used geometric scaling relationships and established biological scaling laws to derive quantitative predictions for the relationships among key drivers of PR. We then used empirical measurements of PR and environmental (soluble reactive phosphate [SRP], carbon [DOC], chlorophyll a [Chl-a)], and temperature) and landscape parameters (lake area [LA] and watershed area [WA]) from a set of 44 lakes that varied in size and trophic status to test our hypotheses. We found that landscape-level processes affected PR through direct effects on DOC and temperature and indirectly via SRP. In accordance with predictions made from known relationships and scaling laws, scale coefficients (the parameter that describes the shape of a relationship between 2 variables) were found to be negative and have an absolute value 1, others <1). We also found evidence of a significant relationship between temperature and SRP. Because our dataset included measurements of respiration from small pond catchments to the largest body of freshwater on the planet, Lake Superior, these findings should be applicable to controls of PR for the great majority of temperate aquatic ecosystems.

  16. Mapping critical loads of nitrogen deposition for aquatic ecosystems in the Rocky Mountains, USA

    USGS Publications Warehouse

    Nanus, Leora; Clow, David W.; Saros, Jasmine E.; Stephens, Verlin C.; Campbell, Donald H.

    2012-01-01

    Spatially explicit estimates of critical loads of nitrogen (N) deposition (CLNdep) for nutrient enrichment in aquatic ecosystems were developed for the Rocky Mountains, USA, using a geostatistical approach. The lowest CLNdep estimates (−1 yr−1) occurred in high-elevation basins with steep slopes, sparse vegetation, and abundance of exposed bedrock and talus. These areas often correspond with areas of high N deposition (>3 kg N ha−1 yr−1), resulting in CLNdep exceedances ≥1.5 ± 1 kg N ha−1 yr−1. CLNdep and CLNdep exceedances exhibit substantial spatial variability related to basin characteristics and are highly sensitive to the NO3− threshold at which ecological effects are thought to occur. Based on an NO3− threshold of 0.5 μmol L−1, N deposition exceeds CLNdep in 21 ± 8% of the study area; thus, broad areas of the Rocky Mountains may be impacted by excess N deposition, with greatest impacts at high elevations.

  17. Assessment of the impact of chlorophyll derivatives to control parasites in aquatic ecosystems.

    PubMed

    Erzinger, Gilmar Sidnei; Souza, Suellen Carolina; Pinto, Luciano Henrique; Hoppe, Roberto; Del Ciampo, Lineu Fernando; Souza, Ozair; Correia, Cláudia Hack Gumz; Häder, Donat-Peter

    2015-05-01

    Several research groups have studied new biopesticides which are less toxic to the environment and capable of controlling the vectors of parasitic diseases, especially in aquatic ecosystems. Pest control by photodynamic substances is an alternative to chemical or other measures, with chlorophyll and its derivatives as the most studied substances supported by their easy availability and low production costs. The impact of chlorophyll derivatives on four different species, a small crustacean (Daphnia similis), a unicellular alga (Euglena gracilis) and two species of fish (Astyanax bimaculatus and Cyprynus carpio) were tested under short-term conditions. In addition, the effects of long-term exposure were evaluated in D. similis and E. gracilis. In short-term tests, mortality of D. similis (EC50 = 7.75 mg/L) was most strongly affected by chlorophyllin, followed by E. gracilis (EC50 = 12.73 mg/L). The fish species showed a greater resistance documented by their EC50 values of 17.58 and 29.96 mg/L in C. carpio and A. bimaculatus, respectively. A risk quotient is calculated by dividing an estimate of exposure by an estimate of effect. It indicated that chlorophyll derivatives can be applied in nature to control the vectors of parasitic diseases under short-term conditions, but long-term exposure requires new formulations. PMID:25750014

  18. Floods, fish, and people: Connecting biogeochemical fluxes to aquatic ecosystem functions and people (Invited)

    NASA Astrophysics Data System (ADS)

    Holtgrieve, G. W.; Arias, M. E.; Chheng, P.

    2013-12-01

    The Lower Mekong River basin, including Tonle Sap Lake (TSL), is the largest inland fishery in the world and a dominant source of protein and income for much of Southeast Asia. Maintaining ecosystem productivity in the face of large-scale environmental change from hydroelectric dams and climate change is critical for economic and social well-being in the region. Yet, we currently lack the most basic understanding of how hydrologic variation relates to fisheries production, nutritional quality, and ultimately livelihoods of people. We will describe past, present, and future research to establish mechanistic connections between the hydrology, ecology, and sustainability of the Mekong ecosystem. Past research includes application of a state-space oxygen mass balance model and continuous dissolved oxygen measurements from four locations to provide the first estimates of gross primary productivity (GPP) and ecosystem respiration (ER) for the Tonle Sap. GPP averaged 4.1 × 2.3 g O2 m-3 d-1 with minimal differences among sites, while ER averaged 24.9 × 20.0 g O2 m-3 d-1, but had greater than six-fold variation among sites. Using our measurements of GPP, we calibrated a hydrodynamic-productivity model and predicted aquatic net primary production of 2.0 × 0.2 g C m-2 d-1 (2.4 × 0.2 million tonnes C y-1). Present research is using stable isotope and fatty acid methyl ester biomarkers to investigate basal carbon sources to the fishery, focusing specifically on the role of biogenic methane oxidation in supporting the food web. Individuals a wide variety of taxa had tissue carbon isotope values (δ13C) ranging from -36 to -57 per mil. These extremely depleted values are best explained by utilization of biogenic methane by methane oxidizing bacteria (MOB) and subsequent grazing of these bacterial by benthic insects and ultimately fishes. The presence of MOB in the food web was confirmed by identifying 16:1ω8 and 18:1ω8 FAME biomarkers specific to these bacteria in fish

  19. Old river beds under urbanization pressure. Can we protect valuable aquatic ecosystems within the cities?

    NASA Astrophysics Data System (ADS)

    Sikorska, Daria; Sikorski, Piotr

    2016-04-01

    Old river channels are valuable ecosystems in the scale of whole Europe. Protected as Natura 2000 habitats they are characterized by high biodiversity and provide various ecosystem services. River regulation, eutrophication or lack of annual flooding result in an impoverishment and disappearance of these habitats. Moreover they are subjected to severe pressure from uncontrolled expansion of the cities. The aim of this study was to determine factors associated with urbanization mostly contributing to impoverishment of the vegetation associated with the old channels and to identify landscape characteristics favouring high diversity and naturalness. We were seeking for indices that could be implemented in spatial management for preservation of these ecosystems. Vegetation inventory of 28 lakes, being former river Vistula beds near Warsaw was held. The lakes were located in an urban-rural gradient from the city centre, suburban zone to rural areas. Mapping of vegetation was performed for aquatic vegetation, rushes and vegetation of the shores (321 relevés). Human pressure was assessed on the basis of landscape composition of the lakes neighbourhood, characteristic features of the reservoir and water physio-chemical properties. High diversity and naturalness of the vegetation associated with former Vistula River beds was proved. Effects of the human pressure in the vegetation composition were recognized in high share of alien species and impoverishment of native plants. Composition was dependant on the intensity of human pressure in the neighbourhood and was mostly related to percentage of built-up areas and road density. Selected measures allowed to explain not more than 30% of plants composition variation which implies strong effect of local factors. Vegetation composition of former river beds changed significantly along urban-rural gradient, though the trend could be noted only to the city border. Several protection activities were proposed favouring high

  20. Springs as Model Systems for Aquatic Ecosystems Ecology: Stoichiometry, Metabolism and Nutrient Limitation

    NASA Astrophysics Data System (ADS)

    Cohen, M. J.; Nifong, R. L.; Kurz, M. J.; Martin, J. B.; Cropper, W. P.; Korhnak, L. V.

    2013-12-01

    Springs have been called nature's chemostats, where low variation in discharge, temperature and chemistry creates a natural laboratory in which to address basic questions about aquatic ecosystems. Ecological stoichiometry posits that patterns of metabolism, trophic energy transfer and community structure arise in response to coupled elemental cycles. In this work we synthesize several recent studies in Florida's iconic springs to explore the overarching hypothesis that stoichiometry can be used to indicate the nutrient limitation status of autotrophs and ecosystem metabolism. Of foremost importance is that the chemically stable conditions observed in springs ensures that autotroph tissue elemental composition, which is thought to vary with environmental supply, is near steady state. Moreover, the elemental ratios of discharging water vary dramatically across our study springs (for example, molar N:P ranges from 0.4:1 to 400:1), subjecting the communities of autotrophs, which are largely conserved across systems, to dramatically different nutrient supply. At the scale of whole ecosystem metabolism, we show that C:N:P ratios are strongly conserved across a wide gradient of environmental supplies, counter to the prediction of stoichiometric plasticity. Moreover, the absence of a relationship between gross primary production and nutrient concentrations or stoichiometry suggests that metabolic homeostasis may be a diagnostic symptom of nutrient saturation. At the scale of individual autotrophs, both submerged vascular plants and filamentous algae, this finding is strongly reinforced, with remarkable within-species tissue C:N:P homeostasis over large gradients, and no statistically significant evidence that gradients in nutrient supply affect autotroph composition. Expanding the suite of elements for which contemporaneous environment and tissue measurements are available to include 19 metals and micronutrients revealed that, while plants were homeostatic across large N

  1. Large Aquatic Ecosystem Restoration Monitoring for Decision Makers: Monitoring to Target and Evaluate Success of Ecosystem Restoration

    EPA Science Inventory

    Monitoring ecosystem restoration at various scales in LAEs can be challenging, frustrating and rewarding. Some of the major ecosystem restoration monitoring occurring in LAEs include: seagrass expansion/contraction; dead zone sizes; oyster reefs; sea turtle nesting; toxic and nu...

  2. The interactive effects of excess reactive nitrogen and climate change on aquatic ecosystems and water resources of the United States

    USGS Publications Warehouse

    Baron, J.S.; Hall, E.K.; Nolan, B.T.; Finlay, J.C.; Bernhardt, E.S.; Harrison, J.A.; Chan, F.; Boyer, E.W.

    2012-01-01

    Nearly all freshwaters and coastal zones of the US are degraded from inputs of excess reactive nitrogen (Nr), sources of which are runoff, atmospheric N deposition, and imported food and feed. Some major adverse effects include harmful algal blooms, hypoxia of fresh and coastal waters, ocean acidification, long-term harm to human health, and increased emissions of greenhouse gases. Nitrogen fluxes to coastal areas and emissions of nitrous oxide from waters have increased in response to N inputs. Denitrification and sedimentation of organic N to sediments are important processes that divert N from downstream transport. Aquatic ecosystems are particularly important denitrification hotspots. Carbon storage in sediments is enhanced by Nr, but whether carbon is permanently buried is unknown. The effect of climate change on N transport and processing in fresh and coastal waters will be felt most strongly through changes to the hydrologic cycle, whereas N loading is mostly climate-independent. Alterations in precipitation amount and dynamics will alter runoff, thereby influencing both rates of Nr inputs to aquatic ecosystems and groundwater and the water residence times that affect Nr removal within aquatic systems. Both infrastructure and climate change alter the landscape connectivity and hydrologic residence time that are essential to denitrification. While Nr inputs to and removal rates from aquatic systems are influenced by climate and management, reduction of N inputs from their source will be the most effective means to prevent or to minimize environmental and economic impacts of excess Nr to the nation’s water resources.

  3. Biomarker/bioindicator response profiles of organisms can help differentiate between sources of anthropogenic stressors in aquatic ecosystems.

    PubMed

    Adams, S M

    2001-01-01

    Aquatic ecosystems can be chronically stressed by multiple environmental factors which originate from a variety of point and non-point sources. In addition, these stressors may vary both spatially and temporally, and, combined with synergestic and cumulative interactions of these stressors, complicate the interpretation and evaluation of stress responses in organisms. To help identify and differentiate between sources of anthropogenic stressors in aquatic systems, a diagnostic approach based on exposure-response profiles in sentinel organisms was developed from the known effects of various anthropogenic activities on biological systems. To generate these exposure-effects profiles, biomarkers of exposure were plotted against bioindicators of corresponding effects for several major anthropogenic activities including petrochemical, pulp and paper, domestic sewage, mining operations, land-development, and agricultural activities. Biomarkers of exposure to environmental stressors varied widely depending on the type of anthropogenic activity involved. Bioindicator effects, however, including histopathological lesions, bioenergetic status, growth, reproductive impairment, and community-level endpoints were similar among several of the major anthropogenic activities because responses at these higher levels are less specific to stressors than are biomarkers. This approach appears useful for helping to identify and diagnose sources of stress in environments impacted by multiple stressors. By identifying the types and sources of environmental stressors impacting key components of biological systems, aquatic ecosystems can be more effectively protected, regulated, and managed to help improve and maintain environmental quality and ecosystem fitness. PMID:23886055

  4. Hydrologic Connectivity as a Window into Pattern Conditions and Formation Processes in Aquatic Ecosystems

    NASA Astrophysics Data System (ADS)

    Larsen, L. G.; Choi, J.; Nungesser, M. K.; Harvey, J. W.

    2011-12-01

    Patterned aquatic ecosystems exhibit different types and degrees of hydrologic connectivity, from isolated open-water patches in some inland marshes, to cross-slope strings and flarks of striped fens, to along-slope ridges and sloughs of low-gradient subtropical wetlands, to dendritic channels of coastal marshes. The nature and degree of this connectivity are closely linked to landscape function. For example, hydrologic connectivity perpendicular to river channel thalwegs relates to the exchange of sediment and nutrients between channels and floodplains, whereas connectivity parallel to a dominant flow direction affects fish migration or the likelihood of contaminant transport. Characteristics of hydrologic connectivity reflect not only the results of landscape pattern but also the mechanisms responsible for pattern creation. Quantifying those connectivity characteristics provides a robust means to identify landscapes likely formed under a consistent set of processes or to compare the output of landscape simulation models to actual landscapes in order to determine whether the models capture the most relevant landscape formation processes. However, established methods for quantifying isotropic patch connectivity are often ill suited for strongly patterned landscapes or hydroscapes in which directional flow is important. Using graph theory principles, we developed two alternative indices of directional hydrologic connectivity: the maximum flow index (MFI) and directional connectivity index (DCI), which quantify the connectivity of flow paths along a particular axis of interest. The MFI is sensitive to the existence of any hydrologic connection along the direction of interest, whereas the DCI is sensitive to the linearity of connections along that direction. Curves of directional connectivity over a range of angular bearings provide a quantitative, information-dense representation of landscape structure that can be related to subtle differences in the physical

  5. Using Remotely Sensed Data and Watershed and Hydrodynamic Models to Evaluate the Effects of Land Cover Land Use Change on Aquatic Ecosystems in Mobile Bay, AL

    NASA Technical Reports Server (NTRS)

    Al-Hamdan, Mohammad; Estes, Maurice G., Jr.; Judd, Chaeli; Woodruff, Dana; Ellis, Jean; Quattrochi, Dale; Watson, Brian; Rodriquez, Hugo; Johnson, Hoyt

    2012-01-01

    Alabama coastal systems have been subjected to increasing pressure from a variety of activities including urban and rural development, shoreline modifications, industrial activities, and dredging of shipping and navigation channels. The impacts on coastal ecosystems are often observed through the use of indicator species. One such indicator species for aquatic ecosystem health is submerged aquatic vegetation (SAV). Watershed and hydrodynamic modeling has been performed to evaluate the impact of land cover land use (LCLU) change in the two counties surrounding Mobile Bay (Mobile and Baldwin) on SAV stressors and controlling factors (temperature, salinity, and sediment) in the Mobile Bay estuary. Watershed modeling using the Loading Simulation Package in C++ (LSPC) was performed for all watersheds contiguous to Mobile Bay for LCLU scenarios in 1948, 1992, 2001, and 2030. Remotely sensed Landsat-derived National Land Cover Data (NLCD) were used in the 1992 and 2001 simulations after having been reclassified to a common classification scheme. The Prescott Spatial Growth Model was used to project the 2030 LCLU scenario based on current trends. The LSPC model simulations provided output on changes in flow, temperature, and sediment for 22 discharge points into the estuary. These results were inputted in the Environmental Fluid Dynamics Computer Code (EFDC) hydrodynamic model to generate data on changes in temperature, salinity, and sediment on a grid throughout Mobile Bay and adjacent estuaries. The changes in the aquatic ecosystem were used to perform an ecological analysis to evaluate the impact on SAV habitat suitability. This is the key product benefiting the Mobile Bay coastal environmental managers that integrates the influences of temperature, salinity, and sediment due to LCLU driven flow changes with the restoration potential of SAVs. Data products and results are being integrated into NOAA s EcoWatch and Gulf of Mexico Data Atlas online systems for

  6. Effect of pesticides used in banana and pineapple plantations on aquatic ecosystems in Costa Rica.

    PubMed

    Diepens, Noël J; Pfennig, Sascha; Van den Brink, Paul J; Gunnarsson, Jonas S; Ruepert, Clemens; Castillo, Luisa E

    2014-01-01

    Current knowledge on fate and effect of agricultural pesticides comes is mainly from temperate ecosystems. More studies are needed in tropical systems in order to assess contamination risks to nontarget endemic tropical species from the extensive use of pesticides e.g. in banana and pineapple plantations. In this study, acute laboratory toxicity tests with organophosphate pesticides ethoprophos and chlorpyrifos were conducted on two Costa Rican species, cladoceran Daphnia ambigua and fish Parachromis dovii. Tests showed that chlorpyrifos was more toxic than ethoprophos to D. ambigua and P. dovii and that D. ambigua was also more sensitive than P. dovii to both pesticides. Additionally, bioassays were performed by exposing D. magna and P. dovii to contaminated water collected from the field. Chemical analyses of field water revealed that fungicides were generally the most frequent pesticide group found, followed by insecticides/nematicides and herbicides. The bioassays and values obtained from the literature confirmed that D. magna was more sensitive to pesticide contamination than P. dovii and that D. ambigua was more sensitive than D. magna, suggesting that the native cladoceran is a more suitable test species than its temperate counterpart. Species sensitivity distributions showed no significant difference in sensitivity between tropical and temperate fish and the arthropod species exposed to chlorpyrifos in this study. Choline esterase activity (ChE) was measured in P. dovii in laboratory tests in order to assess the applicability of this biomarker. ChE inhibition in P. dovii was observed in the laboratory at levels below the LC10 of both ethoprophos and chlorpyrifos, confirming that ChE is an efficient biomarker of exposure. Both indigenous Costa Rican species used in this study were found to be suitable standard tropical test species. Further studies are needed to investigate how protective the safe environmental concentrations, derived from LC50 of native

  7. Organic-matter loading determines regime shifts and alternative states in an aquatic ecosystem

    PubMed Central

    Sirota, Jennie; Baiser, Benjamin; Gotelli, Nicholas J.; Ellison, Aaron M.

    2013-01-01

    Slow changes in underlying state variables can lead to “tipping points,” rapid transitions between alternative states (“regime shifts”) in a wide range of complex systems. Tipping points and regime shifts routinely are documented retrospectively in long time series of observational data. Experimental induction of tipping points and regime shifts is rare, but could lead to new methods for detecting impending tipping points and forestalling regime shifts. By using controlled additions of detrital organic matter (dried, ground arthropod prey), we experimentally induced a shift from aerobic to anaerobic states in a miniature aquatic ecosystem: the self-contained pools that form in leaves of the carnivorous northern pitcher plant, Sarracenia purpurea. In unfed controls, the concentration of dissolved oxygen ([O2]) in all replicates exhibited regular diurnal cycles associated with daytime photosynthesis and nocturnal plant respiration. In low prey-addition treatments, the regular diurnal cycles of [O2] were disrupted, but a regime shift was not detected. In high prey-addition treatments, the variance of the [O2] time series increased until the system tipped from an aerobic to an anaerobic state. In these treatments, replicate [O2] time series predictably crossed a tipping point at ∼45 h as [O2] was decoupled from diurnal cycles of photosynthesis and respiration. Increasing organic-matter loading led to predictable changes in [O2] dynamics, with high loading consistently driving the system past a well-defined tipping point. The Sarracenia microecosystem functions as a tractable experimental system in which to explore the forecasting and management of tipping points and alternative regimes. PMID:23613583

  8. Quantification and Composition Analysis of Small Mobile Colloids from Different Aquatic Ecosystem

    NASA Astrophysics Data System (ADS)

    Yan, Jing; Lazouskaya, Volha; Jin, Yan

    2014-05-01

    Natural colloids, often defined as entities with sizes < 1.0 μm, have attracted much attention due to their small size and large surface area, leading to their high reactivity with and ability to facilitate the transport of contaminants in the subsurface environment. However, the role of mobile colloids in carbon and phosphorus cycling is largely unknown, especially on the role of smaller colloids (< 0.45 μm), which are operationally considered as "dissolved" species in most studies. Our special focus is on smaller colloids in different size fractions. Colloids are sampled from different aquatic ecosystems, such as freshwater, wetland and estuary area, and include soil solution, stream water and groundwater samples. Colloids of various size fractions are separated using centrifugation or membrane filters and quantified gravimetrically and characterized using SEM or TEM with XEDs to analyze the morphology and compositions of colloidal organo-mineral associations. Preliminary results based on stream water at base flow, during storm event and wetland soil water showed that, in general, small natural colloids (0.1 - 0.45 µm or 0.2 - 0.4 µm) contribute significantly to the whole colloidal pools (< 0.7 or 1.2 µm), and even dominant in some samples and play an important role in carbon and phosphorus mobilization. However, colloid concentrations varied with many factors such as stream order, precipitation time and intensity, and redox conditions. In this presentation, we will present results on quantification and characterization of mobile colloids from field samples and factors that control their mobilization and stabilization, and their role in carbon and phosphorus fate and transport.

  9. Accumulation of steroid hormones in soil and its adjacent aquatic environment from a typical intensive vegetable cultivation of North China.

    PubMed

    Zhang, Feng-Song; Xie, Yun-Feng; Li, Xue-Wen; Wang, Dai-Yi; Yang, Lin-Sheng; Nie, Zhi-Qiang

    2015-12-15

    Steroid hormones released from manure agricultural application are a matter of global concern. The residual levels of steroid hormones were studied in a typical intensive vegetable cultivation area in northeast China, with a long history of heavy manure application. Seven steroids (estrone, 17α-estradiol, 17β-estradiol, estriol, testosterone, androstendione and progesterone) were analyzed from soil sampled from vegetable greenhouses, from sediments and water from the adjacent drainage ditch and from the groundwater. The results showed that target steroids were detected in the soil samples, with detection frequencies varying from 3.13 to 100%. The steroid concentrations varied substantially in soils, ranging from below the detection limit to 109.7μg·kg(-1). Three steroids-progesterone, androstendione and estrone-were found to have relatively high residue concentrations in soil, with maximum concentrations of 109.7, 9.83 and 13.30μg·kg(-1), respectively. In adjacent groundwater, all the steroids, with the exception of estrone, were detected in one or more of the 13 groundwater samples. The concentrations of steroids in groundwater ranged from below the method detection limit to 2.38ng·L(-1). Six of the seven (excluding androstendione) were detected in drainage ditch water samples, with concentrations ranging from below the detection limit to 14ng·L(-1). Progesterone, androstendione and estrone accumulated relatively easily in soils; their concentrations in groundwater were lower than those of other steroids. The concentrations of testosterone and estriol were relatively low in soil, while in groundwater were higher than those of other steroids. The residual levels of steroids in soil and groundwater showed a clear spatial variation in the study area. The residual levels of steroid hormones in soil varied substantially between differently planted greenhouses. PMID:26318226

  10. Mycobacterium ulcerans dynamics in aquatic ecosystems are driven by a complex interplay of abiotic and biotic factors

    PubMed Central

    Garchitorena, Andrés; Guégan, Jean-François; Léger, Lucas; Eyangoh, Sara; Marsollier, Laurent; Roche, Benjamin

    2015-01-01

    Host–parasite interactions are often embedded within complex host communities and can be influenced by a variety of environmental factors, such as seasonal variations in climate or abiotic conditions in water and soil, which confounds our understanding of the main drivers of many multi-host pathogens. Here, we take advantage of a combination of large environmental data sets on Mycobacterium ulcerans (MU), an environmentally persistent microorganism associated to freshwater ecosystems and present in a large variety of aquatic hosts, to characterize abiotic and biotic factors driving the dynamics of this pathogen in two regions of Cameroon. We find that MU dynamics are largely driven by seasonal climatic factors and certain physico-chemical conditions in stagnant and slow-flowing ecosystems, with an important role of pH as limiting factor. Furthermore, water conditions can modify the effect of abundance and diversity of aquatic organisms on MU dynamics, which suggests a different contribution of two MU transmission routes for aquatic hosts (trophic vs environmental transmission) depending on local abiotic factors. DOI: http://dx.doi.org/10.7554/eLife.07616.001 PMID:26216042

  11. Think before you flush! A sustainable aquatic eco-system's relation to human health.

    PubMed

    McKeown, Elaine; Pawloski, Judith

    2013-01-01

    What we do every day at work and in our home lives can make a difference in the quality of our environment. Consider, for example, the flushing of pharmaceuticals into the sewer system can lead to water pollution resulting in a threat to aquatic and human life. In contrast, keeping aquatic life healthy may contribute to human health. Some aquatic-based medications are currently on the market. Others are in various stages of development. In this article the authors argue that, for the benefit of both human and marine life, it is time to implement safer disposal methods for unwanted medications. The authors begin by sharing nursing's guiding principles for environmental health; after which they review research related to pharmaceutical pollution of water resources; describe health care treatments derived from marine life; and discuss suggestions for promoting aquatic health. They conclude that by taking care to preserve aquatic life, we contribute to the quality of our own human lives. PMID:23452193

  12. The feasibility of automated online flow cytometry for in-situ monitoring of microbial dynamics in aquatic ecosystems

    PubMed Central

    Besmer, Michael D.; Weissbrodt, David G.; Kratochvil, Bradley E.; Sigrist, Jürg A.; Weyland, Mathias S.; Hammes, Frederik

    2014-01-01

    Fluorescent staining coupled with flow cytometry (FCM) is often used for the monitoring, quantification and characterization of bacteria in engineered and environmental aquatic ecosystems including seawater, freshwater, drinking water, wastewater, and industrial bioreactors. However, infrequent grab sampling hampers accurate characterization and subsequent understanding of microbial dynamics in all of these ecosystems. A logic technological progression is high throughput and full automation of the sampling, staining, measurement, and data analysis steps. Here we assess the feasibility and applicability of automated FCM by means of actual data sets produced with prototype instrumentation. As proof-of-concept we demonstrate examples of microbial dynamics in (i) flowing tap water from a municipal drinking water supply network and (ii) river water from a small creek subject to two rainfall events. In both cases, automated measurements were done at 15-min intervals during 12–14 consecutive days, yielding more than 1000 individual data points for each ecosystem. The extensive data sets derived from the automated measurements allowed for the establishment of baseline data for each ecosystem, as well as for the recognition of daily variations and specific events that would most likely be missed (or miss-characterized) by infrequent sampling. In addition, the online FCM data from the river water was combined and correlated with online measurements of abiotic parameters, showing considerable potential for a better understanding of cause-and-effect relationships in aquatic ecosystems. Although several challenges remain, the successful operation of an automated online FCM system and the basic interpretation of the resulting data sets represent a breakthrough toward the eventual establishment of fully automated online microbiological monitoring technologies. PMID:24917858

  13. The feasibility of automated online flow cytometry for in-situ monitoring of microbial dynamics in aquatic ecosystems.

    PubMed

    Besmer, Michael D; Weissbrodt, David G; Kratochvil, Bradley E; Sigrist, Jürg A; Weyland, Mathias S; Hammes, Frederik

    2014-01-01

    Fluorescent staining coupled with flow cytometry (FCM) is often used for the monitoring, quantification and characterization of bacteria in engineered and environmental aquatic ecosystems including seawater, freshwater, drinking water, wastewater, and industrial bioreactors. However, infrequent grab sampling hampers accurate characterization and subsequent understanding of microbial dynamics in all of these ecosystems. A logic technological progression is high throughput and full automation of the sampling, staining, measurement, and data analysis steps. Here we assess the feasibility and applicability of automated FCM by means of actual data sets produced with prototype instrumentation. As proof-of-concept we demonstrate examples of microbial dynamics in (i) flowing tap water from a municipal drinking water supply network and (ii) river water from a small creek subject to two rainfall events. In both cases, automated measurements were done at 15-min intervals during 12-14 consecutive days, yielding more than 1000 individual data points for each ecosystem. The extensive data sets derived from the automated measurements allowed for the establishment of baseline data for each ecosystem, as well as for the recognition of daily variations and specific events that would most likely be missed (or miss-characterized) by infrequent sampling. In addition, the online FCM data from the river water was combined and correlated with online measurements of abiotic parameters, showing considerable potential for a better understanding of cause-and-effect relationships in aquatic ecosystems. Although several challenges remain, the successful operation of an automated online FCM system and the basic interpretation of the resulting data sets represent a breakthrough toward the eventual establishment of fully automated online microbiological monitoring technologies. PMID:24917858

  14. Interactions of carbon nanotubes with aqueous/aquatic media containing organic/inorganic contaminants and selected organisms of aquatic ecosystems--A review.

    PubMed

    Boncel, Sławomir; Kyzioł-Komosińska, Joanna; Krzyżewska, Iwona; Czupioł, Justyna

    2015-10-01

    Due to their unique molecular architecture translating into numerous every-day applications, carbon nanotubes (CNTs) will be ultimately an increasingly significant environmental contaminant. This work reviews qualitative/quantitative analyses of interactions of various types of CNTs and their chemically modified analogues with aqueous/aquatic media containing organic and inorganic contaminants and selected organisms of aquatic ecosystems. A special emphasis was placed on physicochemical interactions between CNTs as adsorbents of heavy metal cations and aromatic compounds (dyes) with its environmental consequences. The studies revealed CNTs as more powerful adsorbents of aromatic compounds (an order of magnitude higher adsorption capacity) than metal cations. Depending on the presence of natural organic matter (NOM) and/or co-contaminants, CNTs may act as Trojan horse while passing through biological membranes (in the absence of NOM coordinating metal ions). Nanotubes, depending on flow conditions and their morphology/surface chemistry, may travel with natural waters or sediment with immobilized PAHs or metals and/or increase cyto- and ecotoxicity of PAHs/metal ions by their release via competitive complexation, or cause synergic ecotoxicity while adsorbing nutrients. Additionally, toxicity of CNTs against exemplary aquatic microorganisms was reviewed. It was found for Daphnia magna that longer exposures to CNTs led to higher ecotoxicity with a prolonged CNTs excretion. SWCNTs were more toxic than MWCNTs, while hydrophilization of CNTs via oxidation or anchoring thereto polar/positively charged polymer chains enhanced stability of nanotubes dispersion in aqueous media. On the other hand, bioavailability of functionalized CNTs was improved leading to more complex both mechanisms of uptake and cytotoxic effects. PMID:26022284

  15. Formation, transformation and transport of black carbon (charcoal) in terrestrial and aquatic ecosystems.

    PubMed

    Forbes, M S; Raison, R J; Skjemstad, J O

    2006-10-15

    Black carbon (BC) is ubiquitous in terrestrial environments and its unique physical and chemical properties suggest that it may play an important role in the global carbon budget (GCB). A critical issue is whether the global production of BC results in significant amounts of carbon (C) being removed from the short-term bio-atmospheric carbon cycle and transferred to the long-term geological carbon cycle. Several dozen field and laboratory based studies of BC formation during the burning of biomass have been documented. Findings are difficult to interpret because they have been expressed in an inconsistent manner, and because different physical and chemical methods have been used to derive them. High error terms documented in many of these studies also highlight the problems associated with the quantification of the amount of biomass C consumed in fire, the amount of residue produced and the constituents of that residue. To be able to estimate the potential for BC as a carbon sink, issues regarding its definition, the methods used in its identification and measurement, and the way it is expressed in relation to other components of the carbon cycle need to be addressed. This paper presents BC data in a standard way; BC production as a percentage of the amount of C consumed by fire (BC/CC), which can be readily integrated into a larger carbon budget. Results from previous studies and new data from Australian ecosystems were recalculated in this way. As part of this process, several BC estimates derived solely from physical methods were discarded, based on their inability to accurately identify and quantify the BC component of the post-fire residue. Instead, more focus was placed on BC estimates obtained by chemical methods. This recalculated data lowered the estimate for BC formation in forest fires from 4% to 5% to <3% BC/CC. For savannah and grassland fires a value of <3% is consistent with reported data, but considerable variation among estimates remains. An

  16. A National Pilot Study of Mercury Contamination of Aquatic Ecosystems Along Multiple Gradients: Bioaccumulation in Fish

    USGS Publications Warehouse

    Brumbaugh, William G.; Krabbenhoft, David P.; Helsel, Dennis R.; Wiener, James G.; Echols, Kathy R.

    2001-01-01

    Water, sediment, and fish were sampled in the summer and fall of 1998 at 106 sites from 20 U.S. watershed basins to examine relations of mercury (Hg) and methylmercury (MeHg) in aquatic ecosystems. Bioaccumulation of Hg in fish from these basins was evaluated in relation to species, Hg and MeHg in surficial sediment and water, and watershed characteristics. Bioaccumulation was strongly (positively) correlated with MeHg in water (r = 0.63, p < 0.001) but only moderately with the MeHg in sediment (r = 0.33, p < 0.001) or total Hg in water (r = 0.28, p < 0.01). Of the other significantly measured parameters, pH, DOC, sulfate, sediment LOI, and the percent wetlands of each basin were also significantly correlated with Hg bioaccumulation in fish. The best model for predicting Hg bioaccumulation included Me Hg in water, PH of the water, % wetlands in the basin, and the AVS content of the sediment. These four variables accounted for 45% of the variability of the fish fillet Hg concentration normalized (divided) by total length; however, the majority was described by MeHg in water. A MeHg water concentration 0.12 ng/L was on average, associated with a fish fillet Hg concentration of 0.3 mg/kg wet weight for an age-3 fish when all species were considered. For age-3 largemouth bass, a MeHg water concentration of 0.058 ng/L was associated with the 0.3 mg/kg fillet concentration. Based on rankings for Hg in sediment, water, and fish, sampling sites from the following five study basins had the greatest Hg contamination: Nevada Basin and Range, South Florida Basin, Sacramento River Basin (California), Santee River Basin and Caostal Drainages (South Carolina), and the Long Island and New Jersey Coastal DRainags. A sampling and analysis strategy based on this pilot study is planned for all USGS/NAWQA study units over the next decade.

  17. The Life Cycle of Mercury Within the Clear Lake Aquatic Ecosystem: From Ore to Organism

    NASA Astrophysics Data System (ADS)

    Suchanek, T. H.; Suchanek, T. H.; Nelson, D. C.; Nelson, D. C.; Zierenberg, R. A.; King, P.; King, P.; McElroy, K.; McElroy, K.

    2001-12-01

    Clear Lake (Lake County) is located in the geologically active Clear Lake volcanics mercury (Hg) bearing Franciscan formation within the Coast Range of California, which includes over 300 abandoned Hg mines and prospects. Intermittent mining at the Sulphur Bank Mercury Mine (from 1872-1957), now a USEPA SuperFund site, has resulted in approximately 100 metric tonnes of Hg being deposited into the aquatic ecosystem of Clear Lake, with sediment concentrations of total-Hg as high as 650 mg/kg (parts per million = ppm) near the mine, making Clear Lake one of the most Hg contaminated lakes in the world. As a result, largemouth bass and other top predatory fish species often exceed both the Federal USFDA recommended maximum recommended concentrations of 1.0 ppm and the State of California level of 0.5 ppm. Acid rock drainage leaches Hg and high concentrations of sulfate from the mine site through wasterock and subsurface conduits through subsediment advection and eventually upward diffusion into lake sediments and water. When mineral-laden pH 3 fluids from the mine mix with Clear Lake water (pH 8), an alumino-silicate precipitate (floc) is produced that promotes the localized production of toxic methyl Hg. Floc "hot spots" in sediments near the mine exhibit low pH, high sulfate, anoxia and high organic loading which create conditions that promote Hg methylation by microbial activity, especially in late summer and fall. Wind-driven currents transport methyl-Hg laden floc particles throughout Clear Lake, where they are consumed by plankton and benthic invertebrates and bioaccumulated throughout the food web. While Clear Lake biota have elevated concentrations of methyl-Hg, they are not as elevated as might be expected based on the total Hg loading into the lake. A science-based management approach, utilizing over 10 years of data collected on Hg cycling within the physical and biological compartments of Clear Lake, is necessary to affect a sensible remediation plan.

  18. Recent aquatic ecosystem response to environmental events revealed from 210Pb sediment profiles.

    PubMed

    Mulsow, S; Piovano, E; Cordoba, F

    2009-01-01

    The (210)Pb dating method was first introduced by Goldberg (1963), and since then has been applied to study sediment from lakes, estuaries and coastal marine environments. Hundreds of studies around the world have used (210)Pb as a geochronological tool in aquatic ecosystems. However little attention has been paid to the potential of this naturally occurring isotope as an environmental tracer of ecological events. Here we report three instances in which (210)Pb profiles measured on undisturbed sediment cores from lakes, rivers and fjords show us the potential of (210)Pb profile as a tracer of natural and anthropogenic processes. The methodology used here is a suite of techniques combining biogeochemistry (micro-electrodes), paleomagnetism (susceptibility), sediment characteristics (LOI) and visualization (SPI and X-ray) applied to the interpretation of (210)Pb profiles. We measured (210)Pb profiles on sediments from a river, Cruces River (Chile), which recorded a clear shift in the water chemistry caused by a pulp mill effluent to the river. Here metal mobilization and remobilization of the tracer may be the cause of the observed profile. We also measured (210)Pb profiles in sediment from two fjords of Southern Chile (Pillan and Reñihue), the sudden deposition change of fresh (210)Pb with depth observed could very well be the result of bioturbation but it occurred in a seafloor area deprived of bioturbators. In this case, (210)Pb recorded the onset of aquaculture activities (fish farming) that took place two decades ago. Finally, (210)Pb profiles measured in two lakes in the "pampa Argentina": Epecuen and Venado showed a particular shape with depth. These profiles apparently registered a sudden depositional event with recent (210)Pb material, probably related to strong shifts in precipitation and drought cycles in that part of the world. These three examples show that (210)Pb profiles provide valuable information not only on geochronology, but also related to

  19. Site-specific water quality criteria for aquatic ecosystems: A case study of pentachlorophenol for Tai Lake, China.

    PubMed

    Chen, Yi; Yu, Shuangying; Tang, Song; Li, Yabing; Liu, Hongling; Zhang, Xiaohui; Su, Guanyong; Li, Bing; Yu, Hongxia; Giesy, John P

    2016-01-15

    Given the widely varying types of aquatic ecosystems and bioavailability of chemicals, it is important to develop site-specific water quality criteria (WQC) to ensure criteria are neither over- nor under-protective. In the study, using pentachlorophenol (PCP) as an example, several approaches to derive site-specific WQC were investigated, including the conventional species sensitivity distribution (SSD), weighted SSD based on the proportion of each trophic level, and water effect ratio (WER) method. When corrected to a pH of 7.8, the conventional SSD approach resulted in criteria maximum concentration (CMC) and criteria continuous concentration (CCC) of 18.11 and 1.74 μg/L, respectively. If SSD was weighted according to the current species composition in Tai Lake, the CMC and CCC were 32.81 and 4.48 μg/L, respectively. However, available data suggest that many sensitive species inhabiting Tai Lake during 1980s were disappeared. Considering the species composition of the healthier ecosystem in 1980s, the CMC and CCC were 10.99 and 0.38 μg/L, respectively, which provide more protective water quality standards. Water effect ratio (WER) was further used to correct for co-occurrence of other toxicants and factors affecting bioavailability of PCP. A final WER of 4.72 was applied to adjust the criteria derived by using the weighted SSD for the 1980s aquatic community, and the final CMC and CCC obtained were 51.87 and 1.79 μg/L, respectively, at a pH of 7.8. Water quality criteria derived using the 1980s species composition and adjusted with WER were deemed the most appropriate WQC for water management and aquatic life protection. Merits of the various approaches for developing WQC for protection of aquatic species were discussed. PMID:26398452

  20. Aquatic ecosystem responses to Holocene climate change and biome development in boreal, central Asia

    NASA Astrophysics Data System (ADS)

    Mackay, Anson W.; Bezrukova, Elena V.; Leng, Melanie J.; Meaney, Miriam; Nunes, Ana; Piotrowska, Natalia; Self, Angela; Shchetnikov, Alexander; Shilland, Ewan; Tarasov, Pavel; Wang, Luo; White, Dustin

    2012-05-01

    were also significant, but considerably less important. The potential importance of climate and biome development (tundra, steppe, cold deciduous forest and taiga) on different trophic levels (i.e. chironomid and diatom communities) in lake ESM-1 was also assessed using RDA. Climate predictors had a more significant influence on Holocene chironomid assemblages, especially July insolation at 60 °N, estimates of regional precipitation and estimates of northern hemisphere temperature, while only the development of the taiga biome had a significant impact on these primary consumers. Diatom communities also had a small, but significant influence on Holocene chironomid populations, perhaps linked to variation in faunal feeding strategies. In contrast, climatic and biome predictors explained similar amounts of variation in the Holocene diatom assemblage (approximately 20% each), while chironomids themselves as predictors explained just under 7% of diatom variation. Lake acidity was inferred using a diatom inference model. Results suggest that after deglaciation, the lake did not undergo a process of gradual acidification, most likely due to the presence of continuous permafrost and low levels of precipitation, preventing base cations and dissolved organic carbon entering the lake (except for the period between 1.7 and 0.7 ka BP). We conclude that lakes in continental, boreal regions undergo different models of lake ontogeny than oceanic boreal regions. Unlike other regions discussed, climate is a more important driver of ecosystem change than catchment changes. We also demonstrate that the start of the period coincident with the onset of the Little Ice Age resulted in important thresholds crossed in catchment vegetation and aquatic communities.

  1. Managing riverine landscapes as meta-ecosystems

    NASA Astrophysics Data System (ADS)

    Tockner, K.

    2014-12-01

    Aquatic and terrestrial ecosystems are tightly linked through energy, material, information, and organism flows. At the landscape scale, these reciprocal flows are controlled by the composition, configuration, boundary conditions and linkage of individual ecosystem types, thereby forming so-called meta-ecosystems. The relative importance of individual ecosystem types depends on the intrinsic properties (so-called "ecosystem traits"), the setting within the landscape, and the characteristics of interfaces that control cross-system fluxes. For example, the juxtaposition of particular ecosystem types (i.e. their composition and configuration) may alter the magnitude of landscape processes as well as the directions of flow among ecosystem types. Therefore, the meta-ecosystem concept provides a framework to quantify ecosystem diversity, a neglected component of biodiversity, and to test its effects on genetic and species diversity as well as the functional performance in coupled ecosystems. Given their topographic position at the lowest point in the landscape, aquatic ecosystems are particularly susceptible to influences exerted by their surrounding terrestrial environment, both the immediately adjacent riparian zones and the entire catchment that they drain. Questions that need to be tackled may include: What are the consequences of exchange pulses between aquatic and terrestrial ecosystems on the functional performance of individual ecosystems? What are the mechanisms and processes underlying structural and functional biodiversity at aquatic-terrestrial interfaces? In this respect, the meta-ecosystem concept might be very helpful in landscape management and in ecosystem design and engineering.

  2. Burrowing mayflies (Hexagenia) as indicators of aquatic ecosystem health at Sleeping Bear Dunes National Lakeshore, Michigan

    USGS Publications Warehouse

    Edsall, T.A.; Phillips, W.E.

    2004-01-01

    With concern running high for the ecological effects of nutrient introductions in waters near the park, researchers document baseline conditions of aquatic park resources, applying a method that can be fine-tuned for future trend monitoring.

  3. A METHODOLOGY FOR INFERRING THE CAUSES OF OBSERVED IMPAIRMENTS IN AQUATIC ECOSYSTEMS

    EPA Science Inventory

    Biological surveys have become a common technique for determining whether aquatic communities have been injured. However, their results are not useful for identifying management options until the causes of apparent injuries have been identified. Techniques for determining causa...

  4. [Ecological risk assessment of organophosphorus pesticides in aquatic ecosystems of Pearl River Estuary].

    PubMed

    Guo, Qiang; Tian, Hui; Mao, Xiao-Xuan; Huang, Tao; Gao, Hong; Ma, Jian-Min; Wu, Jun-Nian

    2014-03-01

    The risk quotient method and a probabilistic risk assessment method were applied for assessing aquatic ecological risk of nine organophosphorus pesticides, including thimet, dichlorovos, disulfoton, dimethoate, dimethyl parathion, chlorpyrifos, ethoprophos, sumithion and malathion on eight aquatic organisms in the Pearl River Estuary. Results using the risk quotient method revealed that the risk level of opossum shrimp was the highest among eight aquatic organisms of the Pearl River Estuary. The risk of water flea and midge was in medium level, followed by the rest six aquatic organisms, including diatom, oyster, carp, catfish and eel, which were in the low risk by the examined organophosphorus pesticides. It was found that thimet made the largest contribution to total aquatic ecological risk among nine organophosphorus pesticides to every organism. The results from probabilistic risk assessment showed that the total ecological risk in high water period was higher than that in low water period determined by the HC5 under the 95% confidence level. The largest contribution of thimet to total aquatic ecological risk subject to the HC5 in 50% confidence level was regarded as the toxic reference value. The probabilistic risk of a single contaminant showed that thimet and disulfoton were harmful to exceeded 10% organisms in the estuarine. The probabilistic risk of nine pesticides mixture in high water period was also higher than that in low water period, and both risks were greater than 5% which exceeded safety threshold for 95% organisms in the Pearl River Estuary. PMID:24881393

  5. WATER-ROCK INTERACTIONS INFLUENCING MERCURY FATE AND TRANSPORT FROM AN ABANDONED MINE SITE TO AN ADJACENT AQUATIC ECOSYSTEM

    EPA Science Inventory

    Clear Lake, located 150 km north of San Francisco, is one of the largest fresh water lakes in California and is an important economic resource for the region. Elevated mercury levels in fish in Clear Lake were identified in the late 1970s, resulting in a fish consumption advisor...

  6. Relevance of risk predictions derived from a chronic species sensitivity distribution with cadmium to aquatic populations and ecosystems

    USGS Publications Warehouse

    Mebane, C.A.

    2010-01-01

    Criteria to protect aquatic life are intended to protect diverse ecosystems, but in practice are usually developed from compilations of single-species toxicity tests using standard test organisms that were tested in laboratory environments. Species sensitivity distributions (SSDs) developed from these compilations are extrapolated to set aquatic ecosystem criteria. The protectiveness of the approach was critically reviewed with a chronic SSD for cadmium comprising 27 species within 21 genera. Within the data set, one genus had lower cadmium effects concentrations than the SSD fifth percentile-based criterion, so in theory this genus, the amphipod Hyalella, could be lost or at least allowed some level of harm by this criteria approach. However, population matrix modeling projected only slightly increased extinction risks for a temperate Hyalella population under scenarios similar to the SSD fifth percentile criterion. The criterion value was further compared to cadmium effects concentrations in ecosystem experiments and field studies. Generally, few adverse effects were inferred from ecosystem experiments at concentrations less than the SSD fifth percentile criterion. Exceptions were behavioral impairments in simplified food web studies. No adverse effects were apparent in field studies under conditions that seldom exceeded the criterion. At concentrations greater than the SSD fifth percentile, the magnitudes of adverse effects in the field studies were roughly proportional to the laboratory-based fraction of species with adverse effects in the SSD. Overall, the modeling and field validation comparisons of the chronic criterion values generally supported the relevance and protectiveness of the SSD fifth percentile approach with cadmium. ?? 2009 Society for Risk Analysis.

  7. Variability in net ecosystem exchange from hourly to inter-annual time scales at adjacent pine and hardwood forests: a wavelet analysis.

    PubMed

    Stoy, Paul C; Katul, Gabriel G; Siqueira, Mario B S; Juang, Jehn-Yih; McCarthy, Heather R; Kim, Hyun-Seok; Oishi, A Christopher; Oren, Ram

    2005-07-01

    Orthonormal wavelet transformation (OWT) is a computationally efficient technique for quantifying underlying frequencies in nonstationary and gap-infested time series, such as eddy-covariance-measured net ecosystem exchange of CO2 (NEE). We employed OWT to analyze the frequency characteristics of synchronously measured and modeled NEE at adjacent pine (PP) and hardwood (HW) ecosystems. Wavelet cospectral analysis showed that NEE at PP was more correlated to light and vapor pressure deficit at the daily time scale, and NEE at HW was more correlated to leaf area index (LAI) and temperature, especially soil temperature, at seasonal time scales. Models were required to disentangle the impacts of environmental drivers on the components of NEE, ecosystem carbon assimilation (Ac) and ecosystem respiration (RE). Sensitivity analyses revealed that using air temperature rather than soil temperature in RE models improved the modeled wavelet spectral frequency response on time scales longer than 1 day at both ecosystems. Including LAI improved RE model fit on seasonal time scales at HW, and incorporating parameter variability improved the RE model response at annual time scales at both ecosystems. Resolving variability in canopy conductance, rather than leaf-internal CO2, was more important for modeling Ac at both ecosystems. The PP ecosystem was more sensitive to hydrologic variables that regulate canopy conductance: vapor pressure deficit on weekly time scales and soil moisture on seasonal to interannual time scales. The HW ecosystem was sensitive to water limitation on weekly time scales. A combination of intrinsic drought sensitivity and non-conservative water use at PP was the basis for this response. At both ecosystems, incorporating variability in LAI was required for an accurate spectral representation of modeled NEE. However, nonlinearities imposed by canopy light attenuation were of little importance to spectral fit. The OWT revealed similarities and differences in

  8. The influence of historical forestry practices and climate forcing on the sediment retention function of wetlands and their ability to protect downstream aquatic ecosystems

    NASA Astrophysics Data System (ADS)

    Caley, K. A.; Owens, P. N.

    2012-04-01

    Information is currently lacking regarding the variability of a wetland's sediment storage function over time, and the impacts of increased sediment delivery to this function. To address this issue, two wetlands in the Quesnel River Basin in central British Columbia, whose surrounding catchments were logged, were studied. Sediment cores were collected in 2009 from both wetlands, as well as their adjacent lakes, to determine the relative proportion of sediment retained by each feature prior to, during and after forestry practices. Analysis of radionuclides (Pb-210 and Cs-137) was undertaken to determine core chronology and sedimentation rates. Other proxy indicators (magnetic susceptibility, loss-on-ignition, particle size distribution, C:N ratio and geochemical indicators) were used to assess wetland filtration over time, and to trace the movement of allochthonous sediment through the catchment. Climate data were also used to examine whether fluctuations in sedimentation rates are better explained by climatic factors (e.g. precipitation, temperature). Results suggest that there were periods of increased sedimentation associated with both forestry practices and climate forcing (e.g. Pacific Decadal Oscillation, PDO). Despite increases in sediment delivery due to forestry practices and climate changes the wetlands performed important buffering functions, thereby protecting downstream aquatic ecosystems.

  9. Optical properties of natural dissolved organic matter (DOM) in aquatic ecosystems: Applications in ecosystem studies from headwater streams to the deep ocean. (Invited)

    NASA Astrophysics Data System (ADS)

    Jaffe, R.

    2010-12-01

    The study of natural dissolved organic material (DOM) contributes to the better understanding of ecosystem function as the carbon flux between environmental compartments represents an important linkage between terrestrial and aquatic ecosystems. Within freshwater and marine ecosystems, DOM typically represents the largest pool of detrital organic carbon and greatly exceeds the organic carbon present in living biomass. Thus, the sources and fate of DOM are important terms in carbon budgets. DOM can also influence ecosystem function by controlling microbial food webs, act as a means of nutrient transport, buffer pH and influence toxicity and bioavailability of pollutants, among others. DOM composition influences its ‘quality’ and thus its photo- and bio-reactivity, both of which exert a strong control of the diagenetic reworking of this carbon pool. However, the molecular composition of DOM is highly complex and diverse, and its characterization is a serious challenge to analytical chemists. In recent years, several novel analytical approaches to the characterization of DOM have evolved, including those that are highly structure specific and others that provide information on broader molecular characteristics. Whilst the former are usually expensive and time consuming, the latter, often based on optical properties measurements, feature high sample throughput at a reduced cost but at the expense of structural specificity. While both approaches are complementary under ideal conditions, the latter are best suited for studies involving large spatial and temporal scales. The analysis of DOM optical properties, in particular excitation emission matrix (EEM) fluorescence combined with parallel factor analysis (PARAFAC), has emerged as a practical tool for the broad characterization of DOM quality. This presentation will provide examples for the application of EEM-PARAFAC in assessing environmental dynamics of DOM on both spatial and temporal scales, and in both

  10. Marcellus and mercury: Assessing potential impacts of unconventional natural gas extraction on aquatic ecosystems in northwestern Pennsylvania.

    PubMed

    Grant, Christopher J; Weimer, Alexander B; Marks, Nicole K; Perow, Elliott S; Oster, Jacob M; Brubaker, Kristen M; Trexler, Ryan V; Solomon, Caroline M; Lamendella, Regina

    2015-01-01

    Mercury (Hg) is a persistent element in the environment that has the ability to bioaccumulate and biomagnify up the food chain with potentially harmful effects on ecosystems and human health. Twenty-four streams remotely located in forested watersheds in northwestern PA containing naturally reproducing Salvelinus fontinalis (brook trout), were targeted to gain a better understanding of how Marcellus shale natural gas exploration may be impacting water quality, aquatic biodiversity, and Hg bioaccumulation in aquatic ecosystems. During the summer of 2012, stream water, stream bed sediments, aquatic mosses, macroinvertebrates, crayfish, brook trout, and microbial samples were collected. All streams either had experienced hydraulic fracturing (fracked, n = 14) or not yet experienced hydraulic fracturing (non-fracked, n = 10) within their watersheds at the time of sampling. Analysis of watershed characteristics (GIS) for fracked vs non-fracked sites showed no significant differences (P > 0.05), justifying comparisons between groups. Results showed significantly higher dissolved total mercury (FTHg) in stream water (P = 0.007), lower pH (P = 0.033), and higher dissolved organic matter (P = 0.001) at fracked sites. Total mercury (THg) concentrations in crayfish (P = 0.01), macroinvertebrates (P = 0.089), and predatory macroinvertebrates (P = 0.039) were observed to be higher for fracked sites. A number of positive correlations between amount of well pads within a watershed and THg in crayfish (r = 0.76, P < 0.001), THg in predatory macroinvertebrates (r = 0.71, P < 0.001), and THg in brook trout (r = 0.52, P < 0.01) were observed. Stream-water microbial communities within the Deltaproteobacteria also shared a positive correlation with FTHg and to the number of well pads, while stream pH (r = -0.71, P < 0.001), fish biodiversity (r = -0.60, P = 0.02), and macroinvertebrate taxa richness (r = -0.60, P = 0.01) were negatively correlated with the number of well pads within a

  11. The effect of cannibalism intensity on net primary production and dynamics of trophic links in aquatic ecosystems.

    PubMed

    Shirobokova, I M; Pechurkin, N S

    2003-01-01

    A mathematical model was used to investigate the effect of cannibalism intensity on the net primary production and the dynamics of trophic links in an aquatic ecosystem characterized by cannibalism at the upper trophic level. A mathematical model of an aquatic ecosystem has been constructed, with the following principal trophic links: limiting nutrient concentration, producers (phytoplankton), nonpredatory and predatory zooplankton. The model takes into account the age structure of the predator and includes two age groups (the young and adults). The adult predators are cannibals feeding on both nonpredatory zooplankton and their own young, which consume phytoplankton. It has been found that when cannibalism intensity increases above a certain level, the concentrations of both adults and the young of the predators decrease. At the same time, the concentrations of the nonpredatory zooplankton and of nutrients increase, while the biomass of producers decreases. When the cannibalism intensity is low, the net primary production of the system increases to a certain level correlated with the increase in cannibalism intensity and drops sharply when the level of consumption of young is high. There is an optimal intensity of cannibalism, at which the productivity in the photosynthesis link is maximal. PMID:14503511

  12. Conducting a battery of bioassays for gold nanoparticles to derive guideline value for the protection of aquatic ecosystems.

    PubMed

    Nam, Sun-Hwa; Shin, Yu-Jin; Lee, Woo-Mi; Kim, Shin Woong; Kwak, Jin Il; Yoon, Sung-Ji; An, Youn-Joo

    2015-05-01

    Gold nanoparticles (Au-NPs) are used in many applications, including the manufacture of products like cosmetics, paints, and electrochemical immunosensors, and in the detection, diagnosis, and treatment of tumors. However, there are no legal or recommended guidelines for protecting aquatic ecosystems from Au-NPs. In this study, we conducted a battery of bioassays and present toxicity values for two bacteria, one alga, one euglena, three cladoceran, and two fish species that were exposed to Au-NPs. Guideline values for protecting aquatic ecosystems from Au-NPs were derived using methods that are generally used to derive water-quality guidelines and are used in Australia, New Zealand, Canada, the European Community (EC), and the USA. Au-NPs had adverse effects on all test species, including growth inhibition of both bacteria, the alga, and the euglena; mortality and immobilization in the three cladocerans; and developmental malformations in the embryos and larvae of the two fish. Guideline values of 0.15 and 0.04 × 10(10) particles/mL were derived for Au-NPs using a species sensitivity distribution (SSD) and assessment factor. The guideline value derived for Au-NPs using an assessment factor was more stringent than that derived using SSD. This is the first study to derive guideline values for nanoparticles in water environments. PMID:24983899

  13. Exploring new Routes for Identifying Phosphorus Species in Terrestrial and Aquatic Ecosystems with 31P NMR

    NASA Astrophysics Data System (ADS)

    Vestergren, Johan; Persson, Per; Sundman, Annelie; Ilstedt, Ulrik; Giesler, Reiner; Schleucher, Jürgen; Gröbner, Gerhard

    2014-05-01

    Phosphorus (P) is the primary growth-limiting nutrient in some of the world's biomes. Rock phosphate is a non-renewable resource and the major source of agricultural fertilizers. Predictions of P consumption indicate that rock phosphate mining may peak within 35 years, with severe impacts on worldwide food production1. Organic P compounds constitute a major fraction of soil P, but little is known about the dynamics and bioavailability of organic P species. Our aim is to develop new liquid and solid state 31P-NMR (nuclear magnetic resonance) techniques to identify P-species in water and soils; information required for correlating P speciation with plant and soil processes2, and eventually to improve P use. Soil organic P is frequently extracted using NaOH/EDTA, followed by characterization of the extract by solution 31P-NMR. However, the obtained NMR spectra usually have poor resolution due to line broadening caused by the presence of paramagnetic ions. Therefore, we successfully developed an approach to avoid paramagnetic line broadening by precipitation of metal sulfides. Sulfide precipitation dramatically reduces NMR line widths for soil extracts, without affecting P-composition. The resulting highly improved resolution allowed us to apply for the first time 2D 1H,31P-NMR methods to identify different P monoesters in spectral regions which are extremely crowded in 1D NMR spectra.3 By exploiting 2D 1H-31P NMR spectra of soil extracts we were able to unambiguously identify individual organic P species by combining 31P and 1H chemical shifts and coupling constants. This approach is even suitable for a structural characterization of unknown P-components and for tracing degradation pathways between diesters and monoesters3,4.Currently we apply our approach on boreal4 and tropical soils with focus on Burkina Faso. In addition we also monitor P-species in aqueos ecosystems. For this purpose stream water from the Krycklan catchment in northern Sweden5 has been used to

  14. From a microcosm to the catchment scale: studying the fate of organic runoff pollutants in aquatic ecosystems

    NASA Astrophysics Data System (ADS)

    Böttcher, T.; Schroll, R.

    2009-04-01

    Spray-drift, drainage, erosion and runoff events are the major causes responsible for deportation of agrochemicals as micropollutants to aquatic non-target sites. These processes can lead to the contamination of nearby freshwater ecosystems with considerably high concentrations of xenobiotics. Thus, it is important to unravel the fate of these pollutants and to evaluate their ecological effects. A novel approach to address this goal was established by the development of a microcosm with multiple sampling abilities enabling quantitative assessment of organic volatilisation, mineralization, metabolization and distribution within the aquatic ecosystem. This microcosm system was designed to support modelling approaches of the catchment scale and gain insights into the fate of pesticides simulating a large scale water body. The potential of this microcosm was exemplified for Isoproturon (IPU), a phenylurea derived systemic herbicide, which is frequently found as contaminant in water samples and with the free-floating macrophyte Lemna minor as non-target species, that is common to occur in rural water bodies. During 21 days exposure time, only a small amount of 14C labeled IPU was removed from the aquatic medium. The major portion (about 5%) was accumulated by Lemna minor resulting in a BCF of 15.8. IPU-volatilisation was very low with 0.13% of the initially applied herbicide. Only a minor amount of IPU was completely metabolized, presumably by rhizosphere microorganisms and released as 14CO2. The novel experimental system allowed to quantitatively investigate the fate of IPU and showed a high reproducibility with a mean average 14C-recovery rate of 97.1

  15. Terrestrial and aquatic ecosystem responses to late Holocene climate change recorded in the sediments of Lochan Uaine, Cairngorms, Scotland

    NASA Astrophysics Data System (ADS)

    Oldfield, Frank; Battarbee, Richard W.; Boyle, John F.; Cameron, Nigel G.; Davis, Basil; Evershed, Richard P.; McGovern, Andrew D.; Jones, Vivienne; Thompson, Roy; Walker (née Wake), Rebecca

    2010-04-01

    We summarise the results of a range of sediment-based studies at Lochan Uaine, a remote corrie lake in the heart of the Cairngorm massif in Scotland. The site lies above the Holocene forest limit and has been minimally affected by human activities. The results presented are mainly based on magnetic measurements, element analysis, granulometry, organic geochemical analysis and pollen analysis carried out over a period of some 15 years. The magnetic properties and element concentrations record a coherent sequence of changes reflecting mainly stages in catchment erosion. In terms of the chronology developed for the sedimentary record from the site, increases in allochthonous, minerogenic sediment delivery to the lake occurred around 1000 BC, AD 330-480 and AD 1260-1410. The only notable change in the pollen diagram records a period of deforestation at lower altitude predating the last of the periods of increased erosion. The organic geochemistry analyses record a series of higher frequency responses in the aquatic ecosystem, already noted in previous papers, e.g. Battarbee et al. (2001). These include fluctuations in organic carbon content and in the concentrations of biomarkers indicative of changing lake productivity. Both the terrestrial and aquatic ecosystem responses are superimposed on a longer-term trend of declining aquatic productivity, progressive catchment weathering and increasing erosion. The sediments of Lochan Uaine thus appear to have recorded complex system responses on three timescales reflecting (a) the long term decline in northern hemisphere insolation during the Holocene, (b) the millennial scale forcing of the kind found in many other mid-late Holocene records and (c) much shorter term, quasi-cyclic but clearly a-periodic sub-millennial fluctuations.

  16. Development of a dynamic model for estimating the food web transfer of chemicals in small aquatic ecosystems.

    PubMed

    Nfon, Erick; Armitage, James M; Cousins, Ian T

    2011-11-15

    A dynamic combined fate and food web model was developed to estimate the food web transfer of chemicals in small aquatic ecosystems (i.e. ponds). A novel feature of the modeling approach is that aquatic macrophytes (submerged aquatic vegetation) were included in the fate model and were also a food item in the food web model. The paper aims to investigate whether macrophytes are effective at mitigating chemical exposure and to compare the modeling approach developed here with previous modeling approaches recommended in the European Union (EU) guideline for risk assessment of pesticides. The model was used to estimate bioaccumulation of three hypothetical chemicals of varying hydrophobicity in a pond food web comprising 11 species. Three different macrophyte biomass densities were simulated in the model experiments to determine the influence of macrophytes on fate and bioaccumulation. Macrophytes were shown to have a significant effect on the fate and food web transfer of highly hydrophobic compounds with log KOW>=5. Modeled peak concentrations in biota were highest for the scenarios with the lowest macrophyte biomass density. The distribution and food web transfer of the hypothetical compound with the lowest hydrophobicity (log KOW=3) was not affected by the inclusion of aquatic macrophytes in the pond environment. For the three different hypothetical chemicals and at all macrophyte biomass densities, the maximum predicted concentrations in the top predator in the food web model were at least one order of magnitude lower than the values estimated using methods suggested in EU guidelines. The EU guideline thus provides a highly conservative estimate of risk. In our opinion, and subject to further model evaluation, a realistic assessment of dynamic food web transfer and risk can be obtained using the model presented here. PMID:21962596

  17. Heavy metal contents in water, sediment and fish in a karst aquatic ecosystem of the Plitvice Lakes National Park (Croatia).

    PubMed

    Vukosav, Petra; Mlakar, Marina; Cukrov, Neven; Kwokal, Zeljko; Pižeta, Ivanka; Pavlus, Natalija; Spoljarić, Ivanka; Vurnek, Maja; Brozinčević, Andrijana; Omanović, Dario

    2014-03-01

    An evaluation of the quality status of the pristine karst, tufa depositing aquatic environment of the Plitvice Lakes National Park based on the analysis of heavy (ecotoxic) metals was examined for the first time. Analyses of trace metals in water, sediment and fish (Salmo trutta, Oncorhynchus mykiss, Squalius cephalus) samples were conducted either by stripping voltammetry (Zn, Cd, Pb and Cu) or cold vapour atomic absorption spectrometry (Hg). The concentration of dissolved trace metals in water was very low revealing a pristine aquatic environment (averages were, in ng/L: 258 (Zn), 10.9 (Cd), 11.7 (Pb), 115 (Cu) and 1.22 (Hg)). Slightly enhanced concentrations of Cd (up to 50 ng/L) and Zn (up to 900 ng/L) were found in two main water springs and are considered as of natural origin. Observed downstream decrease in concentration of Cd, Zn and Cu in both water and sediments is a consequence of the self-purification process governed by the formation and settling of authigenic calcite. Anthropogenic pressure was spotted only in the Kozjak Lake: Hg concentrations in sediments were found to be up to four times higher than the baseline value, while at two locations, Pb concentrations exceeded even a probable effect concentration. The increase of Hg and Pb was not reflected on their levels in the fish tissues; however, significant correlations were found between Cd level in fish tissues (liver and muscle) and in the water/sediment compartments, while only partial correlations were estimated for Zn and Cu. A high discrepancy between values of potentially bioavailable metal fraction estimated by different modelling programs/models raised the question about the usefulness of these data as a parameter in understanding/relating the metal uptake and their levels in aquatic organism. The aquatic environment of the Plitvice Lakes National Park is characterized, in general, as a clean ecosystem. PMID:24288066

  18. Patterns of Life in the Water. Student Field Studies of Two of Franklin County's Aquatic Ecosystems.

    ERIC Educational Resources Information Center

    O'Toole, Kathleen P.

    Described in this manual are two field investigations which utilize the natural environment to teach ecological principles to high school students. In groups of five to ten, students study two aquatic environments and then prepare a booklet which summarizes their work. The manual is divided into four parts: (1) teacher's guide; (2) student's…

  19. A FRAMEWORK TO ASSESS THE RELATIVE VULNERABILITY OF AQUATIC ECOSYSTEM SERVICES TO GLOBAL STRESSORS

    EPA Science Inventory

    Over the next several years, the Environmental Protection Agency's (EPA's) Global Change Research Program within the Office of Research and Development (ORD) will conduct a series of case studies in different regions of the United States to evaluate potential changes in aquatic e...

  20. Aquatic Ecosystem Services in the 21st Century Northeast Corridor: Assessment Using a Regional Earth System Model

    NASA Astrophysics Data System (ADS)

    Rosenzweig, B.; Miara, A.; Stewart, R. J.; Wollheim, W. M.; Vorosmarty, C. J.

    2012-12-01

    Aquatic ecosystems of the Northeast United States will be significantly impacted by both global climate change and the regional-scale strategic management decisions made in the next few years. We have developed a Regional Earth System Model for the Northeast Corridor (NE-RESM) that simulates the impacts of climate, land use, and development policy on the interacting cycles of energy, water, carbon and nutrients. The NE-RESM will provide a unique and critically needed tool for policymakers to understand how their current decisions will impact ecosystem services over the 21st Century. To test our modeling framework, we conducted a retrospective experiment focusing on the water-energy-economy nexus during the period 2000-2010. Component models were developed to 'translate' physical outputs from the NE-RESM - such as stream discharge and water temperature - into ecosystem services including water regulation for thermoelectric cooling and the ability for streams to serve as a refugia for wildlife. Simulations were performed both with and without Clean Water Act limits on thermal pollution. Through this work, we were able to obtain spatially distributed information on how these laws impact power generation by the thermoelectric sector but also enable Northeast streams to serve as habitat for temperature-sensitive aquatic species (Brook Trout, Atlantic Salmon, River Herring and the American Eel). Our ongoing research examines future climate and policy scenarios through 2100. We are considering the impact of changing land cover patterns (a return to agriculture vs. suburban sprawl) and various strategies to meet energy and municipal water needs under different Representative Concentration Pathways (RCPs) developed for the Intergovernmental Panel on Climate Change's Fifth Assessment Report (IPCC AR5).

  1. Project AProWa: a national view on managing trade-offs between agricultural production and conservation of aquatic ecosystems

    NASA Astrophysics Data System (ADS)

    Dietzel, Anne; Rahn, Eric; Stamm, Christian

    2014-05-01

    Swiss agriculture is legally committed to fulfill several, partially conflicting goals such as agricultural production on the one hand and the conservation of natural resources on the other hand. In the context of the research project AProWa ("Agricultural Production and Water"), the relationships between the production aspect and the conservation of aquatic ecosystems is analyzed with a holistic approach. Agricultural production and the protection of water resources have high potential for conflicts: Farmers use ground and surface water to irrigate their fields. On the other hand, drainage systems enable the production on otherwise unfavorably wet soils. These in turn often affect ground water recharge and divert precipitation directly into surface waters, which changes their hydrological regime. Typically, drainage systems also elevate the input of nutrients and pesticides into the water bodies. In general, applied fertilizers, plant protection products, veterinary drugs and phytohormones of cultivated plants are introduced into the ground and surface waters through different processes such as drift, leaching, runoff, preferential flow or erosion. They influence the nutrient cycles and ecological health of aquatic systems. The nutrient and pesticide loss processes themselves can be altered by tillage operations and other agricultural practices. Furthermore, the competition for space can lead to additional conflicts between agriculture and the protection of aquatic ecosystems. For example, channelized or otherwise morphologically changed rivers do not have a natural discharge pattern and are often not suitable for the local flora and fauna; but naturally meandering rivers need space that cannot be used for agriculture. In a highly industrialized and densely populated country like Switzerland, all these potential conflicts are of importance. Although it is typically seen as a water-rich country, local and seasonal overexploitation of rivers through water extraction

  2. The remote sensing of aquatic macrophytes Part 1: Color-infrared aerial photography as a tool for identification and mapping of littoral vegetation. Part 2: Aerial photography as a quantitative tool for the investigation of aquatic ecosystems. [Lake Wingra, Wisconsin

    NASA Technical Reports Server (NTRS)

    Gustafson, T. D.; Adams, M. S.

    1973-01-01

    Research was initiated to use aerial photography as an investigative tool in studies that are part of an intensive aquatic ecosystem research effort at Lake Wingra, Madison, Wisconsin. It is anticipated that photographic techniques would supply information about the growth and distribution of littoral macrophytes with efficiency and accuracy greater than conventional methods.

  3. ORGANIZATION AND ADAPTATION OF AQUATIC LABORATORY ECOSYSTEMS EXPOSED TO THE PESTICIDE DIELDRIN

    EPA Science Inventory

    A system of generalizations pertaining to the organization, development and persistence, adaptation, and productivity of ecological systems and their response to toxic substances was formulated. Laboratory ecosystems composed of persistent populations of guppies, amphipods, snail...

  4. 76 FR 55060 - Aquatic Ecosystems, Water Quality, and Global Change: Challenges of Conducting Multi-Stressor...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-06

    ... resilience of ecosystems and human systems to a variety of existing stresses and mal- adaptations. DATES: The... a result of existing global change stresses and mal-adaptations. The work described in this...

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

    NASA Astrophysics Data System (ADS)

    Wollheim, W. M.; Stewart, R. J.; Aiken, G. R.; Butler, K. D.; Morse, N. B.; Salisbury, J.

    2015-08-01

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

  6. Mycobacterium ulcerans Ecological Dynamics and Its Association with Freshwater Ecosystems and Aquatic Communities: Results from a 12-Month Environmental Survey in Cameroon

    PubMed Central

    Garchitorena, Andrés; Roche, Benjamin; Kamgang, Roger; Ossomba, Joachim; Babonneau, Jérémie; Landier, Jordi; Fontanet, Arnaud; Flahault, Antoine

    2014-01-01

    Background Mycobacterium ulcerans (MU) is the agent responsible for Buruli Ulcer (BU), an emerging skin disease with dramatic socioeconomic and health outcomes, especially in rural settings. BU emergence and distribution is linked to aquatic ecosystems in tropical and subtropical countries, especially to swampy and flooded areas. Aquatic animal organisms are likely to play a role either as host reservoirs or vectors of the bacilli. However, information on MU ecological dynamics, both in space and time, is dramatically lacking. As a result, the ecology of the disease agent, and consequently its mode of transmission, remains largely unknown, which jeopardizes public health attempts for its control. The objective of this study was to gain insight on MU environmental distribution and colonization of aquatic organisms through time. Methodology/Principal Findings Longitudinal sampling of 32 communities of aquatic macro-invertebrates and vertebrates was conducted from different environments in two BU endemic regions in Cameroon during 12 months. As a result, 238,496 individuals were classified and MU presence was assessed by qPCR in 3,084 sample-pools containing these aquatic organisms. Our study showed a broad distribution of MU in all ecosystems and taxonomic groups, with important regional differences in its occurrence. Colonization dynamics fluctuated along the year, with the highest peaks in August and October. The large variations observed in the colonization dynamics of different taxonomic groups and aquatic ecosystems suggest that the trends shown here are the result of complex ecological processes that need further investigation. Conclusion/Perspectives This is the largest field study on MU ecology to date, providing the first detailed description of its spatio-temporal dynamics in different aquatic ecosystems within BU endemic regions. We argue that coupling this data with fine-scale epidemiological data through statistical and mathematical models will provide a

  7. The mysteriously variable half-life of dissolved organic matter in aquatic ecosystems: artefact or insight?

    NASA Astrophysics Data System (ADS)

    Evans, Chris; Fovet, Ophelie; Jones, Tim; Jones, Davey; Moldan, Filip; Futter, Martyn

    2016-04-01

    Dissolved organic matter (DOM) fluxes from land to water represent an important loss term in the terrestrial carbon balance, a major pathway in the global carbon cycle, a significant influence on aquatic light, nutrient and energy regimes, and an important concern for drinking water production. Although freshwaters are now recognised as zones of active carbon cycling, rather than passive conduits for carbon transport, evidence regarding the magnitude of, and controls on, DOM cycling in aquatic systems is incomplete and in some cases seemingly contradictory, with DOM 'half-lives' ranging from a few days to many years. Bringing together experimental, isotopic, catchment mass balance and modelling data, we suggest that apparently conflicting results can be reconciled through understanding of differences in: i) the terrestrial sources of DOM within heterogeneous landscapes, and consequent differences in its reactivity and stoichiometry; ii) experimental methodologies (i.e. which reactions are actually being measured), and iii) the extent of prior transformation of DOM upstream of the point of study. We argue that rapid photo-degradation, particularly of peat-derived DOM, is a key process in headwaters, whilst apparently slow DOM turnover in downstream, agriculturally-influenced lakes and rivers can partly be explained by the offsetting effect of in situ DOM production. This production appears to be strongly constrained by nutrient supply, thus linking DOM turnover and composition to the supply of inorganic nutrient inputs from diffuse agricultural pollution, and also providing a possible mechanistic link between aquatic DOM production and terrestrial DOM breakdown via the mineralisation and re-assimilation of organic nutrients. A more complete conceptual understanding of these interlinked processes will provide an improved understanding of the sources and fate of aquatic DOM, its role in the global carbon cycle, and the impact of anthropogenic activities, for example

  8. Techniques for monitoring the environmental impact of insecticides on aquatic ecosystems. Agricultural handbook, (final)

    SciTech Connect

    Not Available

    1984-01-01

    Aquatic sampling has evolved at an exceptional pace in recent years. The manual is designed primarily for the field technician rather than the experienced research ecologist. Its purpose is to describe the equipment, procedures, and hypotheses potentially applicable to or previously used for studies of the impact of spruce budworm pesticides. The manual focuses on the field study of fresh water macroinvertebrates and fish, and covers both lotic (flowing) and lentic (stagnant) environments.

  9. Trophic complexity enhances ecosystem functioning in an aquatic detritus-based model system.

    PubMed

    Jabiol, Jérémy; McKie, Brendan G; Bruder, Andreas; Bernadet, Caroline; Gessner, Mark O; Chauvet, Eric

    2013-09-01

    1. Understanding the functional significance of species interactions in ecosystems has become a major challenge as biodiversity declines rapidly worldwide. Ecosystem consequences arising from the loss of diversity either within trophic levels (horizontal diversity) or across trophic levels (vertical diversity) are well documented. However, simultaneous losses of species at different trophic levels may also result in interactive effects, with potentially complex outcomes for ecosystem functioning. 2. Because of logistical constraints, the outcomes of such interactions have been difficult to assess in experiments involving large metazoan species. Here, we take advantage of a detritus-based model system to experimentally assess the consequences of biodiversity change within both horizontal and vertical food-web components on leaf-litter decomposition, a fundamental process in a wide range of ecosystems. 3. Our concurrent manipulation of fungal decomposer diversity (0, 1 or 5 species), detritivore diversity (0, 1 or 3 species), and the presence of predatory fish scent showed that trophic complexity is key to eliciting diversity effects on ecosystem functioning. Specifically, although fungi and detritivores tended to promote decomposition individually, rates were highest in the most complete community where all trophic levels were represented at the highest possible species richness. In part, the effects were trait-mediated, reflected in the contrasting foraging responses of the detritivore species to predator scent. 4. Our results thus highlight the importance of interactive effects of simultaneous species loss within multiple trophic levels on ecosystem functioning. If a common phenomenon, this outcome suggests that functional ecosystem impairment resulting from widespread biodiversity loss could be more severe than inferred from previous experiments confined to varying diversity within single trophic levels. PMID:23574276

  10. Cumulative effect assessment in Canada: a regional framework for aquatic ecosystems

    SciTech Connect

    Dube, Monique G

    2003-10-01

    Sustainable development of the aquatic environment depends upon routine and defensible cumulative effects assessment (CEA). CEA is the process of predicting the consequences of development relative to an assessment of existing environmental quality. Theoretically, it provides an on-going mechanism to evaluate if levels of development exceed the environment's assimilative capacity; i.e., its ability to sustain itself. In practice, the link between CEA and sustainable development has not been realized because CEA concepts and methods have developed along two dichotomous tracks. One track views CEA as an extension of the environmental assessment (EA) process for project developments. Under this track, stressor-based (S-B) methods have been developed where the emphasis is on local, project-related stressors, their link with aquatic indicators, and the potential for environmental effects through stressor-indicator interactions. S-B methods focus on the proposed development and prediction of project-related effects. They lack a mechanism to quantify existing aquatic quality especially at scales broader than an isolated development. This limitation results in the prediction of potential effects relative to a poorly defined baseline state. The other track views CEA as a broader, regional assessment tool where effects-based (E-B) methods specialize in quantification of existing aquatic effects over broad spatial scales. However, the predictive capabilities of E-B methods are limited because they are retrospective, i.e., the stressor causing the effect is identified after the effect has been measured. When used in isolation, S-B and E-B methods do not address CEA in the context necessary for sustainable development. However, if the strengths of these approaches were integrated into a holistic framework for CEA, an operational mechanism would exist to better monitor and assess sustainable development of our aquatic resources. This paper reviews the existing conceptual basis

  11. Sedimentation plan to assess the impact of geothermal activities to the aquatic ecosystem in the Geyers Calistoga KGRA

    SciTech Connect

    Ireland, R.R.

    1981-05-19

    The prevention of sedimentation or siltation in aquatic ecosystems is always a key environmental issue in the development and operation of power plant units. This report describes a field program which will assess the amount of sedimentation in the streams and tributaties of the Geysers-Calistoga Known Geothermal Resource Area (KGRA) due to development-related or other site-specific activities. This sediment plan is one part of a four part venture - the others are water quality, benthic invertebrates and fisheries studies - initiated by the California Energy Commission and involving numerous California organizations. Included in this report are the cost breakdowns for each phase, maps and rationale of the sampling sites, the methodology for the laboratory sample processing, and examples of the type of graphic and tabular output expected.

  12. Uptake of uranium by aquatic plants growing in fresh water ecosystem around uranium mill tailings pond at Jaduguda, India.

    PubMed

    Jha, V N; Tripathi, R M; Sethy, N K; Sahoo, S K

    2016-01-01

    Concentration of uranium was determined in aquatic plants and substrate (sediment or water) of fresh water ecosystem on and around uranium mill tailings pond at Jaduguda, India. Aquatic plant/substrate concentration ratios (CRs) of uranium were estimated for different sites on and around the uranium mill tailings disposal area. These sites include upstream and downstream side of surface water sources carrying the treated tailings effluent, a small pond inside tailings disposal area and residual water of this area. Three types of plant groups were investigated namely algae (filamentous and non-filamentous), other free floating & water submerged and sediment rooted plants. Wide variability in concentration ratio was observed for different groups of plants studied. The filamentous algae uranium concentration was significantly correlated with that of water (r=0.86, p<0.003). For sediment rooted plants significant correlation was found between uranium concentration in plant and the substrate (r=0.88, p<0.001). Both for other free floating species and sediment rooted plants, uranium concentration was significantly correlated with Mn, Fe, and Ni concentration of plants (p<0.01). Filamentous algae, Jussiaea and Pistia owing to their high bioproductivity, biomass, uranium accumulation and concentration ratio can be useful for prospecting phytoremediation of stream carrying treated or untreated uranium mill tailings effluent. PMID:26360459

  13. Benthic aquatic ecosystems across the Permian-Triassic transition: record from biogenic structures in fluvial sandstones, central Transantarctic Mountains

    NASA Astrophysics Data System (ADS)

    Miller, M. F.

    2000-07-01

    The effect of the Permian extinction in communities inhabiting sandy stream bottoms can be evaluated using trace fossils as proxies for body fossils. Permian and Triassic sandstones exposed in the Beardmore and Shackleton Glacier areas (central Transantarctic Mountains) were deposited in sandy braided streams and contain four types of trace fossils (vertical shafts and horizontal, bilobed and chevron traces). These traces were produced by a single type of animal that moved in the top 30 cm of sediment and dominated the benthic community. Evidence for a single producer includes similar size (diameter) of all traces and change within single specimens from one trace type to another. The animal was not affected by the Permian extinction event, as evidenced by its equal abundance within the Permian (Buckley Formation) and Triassic (Fremouw Formation) fluvial sandstones in the Beardmore Glacier area. Based on trace morphology and on domination of modern sandy river ecosystems by insects, the producer most likely was an insect, although its more precise identity is problematic. Although families of insects with modern aquatic burrowers are not known before the Jurassic, these trace fossils may show that these burrowers were present earlier than the insect body-fossil record suggests. Alternatively, archaic insect groups, many of which became extinct at the end-Permian and are known to have been aquatic but not infaunal, may have included some active burrowers that were unscathed by the Permian extinction.

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

    SciTech Connect

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

    1996-12-31

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

  15. RELATIONSHIPS AMONG EXCEEDENCES OF CHEMICAL CRITERIA OR GUIDELINES, THE RESULTS OF AMBIENT TOXICITY TESTS AND COMMUNITY METRICS IN AQUATIC ECOSYSTEMS (FINAL)

    EPA Science Inventory

    The EPA document, Relationships Among Exceedances of Chemical Criteria or Guidelines, the Results of Ambient Toxicity Tests, and Community Metrics in Aquatic Ecosystems, presents two studies where the three general approaches for the ecological assessment of contaminant ex...

  16. global research program: LTG2. Assess the potential impacts of global change on water quality and aquatic ecosystems in the US

    EPA Science Inventory

    Includes research on the effects of land use practices and climate change on terrestrial-aquatic linkages in the Willamette Basin Oregon and implications for water resources; assessment of the vulnerability of Pacific Coast estuarine ecosystems and population viability of key Pac...

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

    ERIC Educational Resources Information Center

    Pearson, Nolan E.

    This module is part of a series designed to be used by life science students for instruction in the application of physical theory to ecosystem operation. Most modules contain computer programs which are built around a particular application of a physical process. This module is one of two units on the foundations of physical theory and the…

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

    ERIC Educational Resources Information Center

    Roseman, Leonard D.

    These materials were designed to be used by life science students for instruction in the application of physical theory to ecosystem operation. Most modules contain computer programs which are built around a particular application of a physical process. This module is concerned with the exchange of energy between an organism and its environment in…

  19. Exploring Fish Diversity as a Determinant of Ecosystem Properties in Aquatic Food Webs

    ERIC Educational Resources Information Center

    Carey, Michael P.

    2009-01-01

    Dramatic biodiversity changes occurring globally from species loss and invasion have altered native food webs and ecosystem processes. My research objectives are to understand the consequences of fish diversity to freshwater systems by (1) examining the food web consequences of multiple top predators, (2) determining how biodiversity influences…

  20. Calculus-Integration. Physical Processes in Terrestrial and Aquatic Ecosystems, Applied Mathematics.

    ERIC Educational Resources Information Center

    Hertzberg, Richard C.

    These materials were designed to be used by life science students for instruction in the application of physical theory to ecosystem operation. Most modules contain computer programs which are built around a particular application of a physical process. The module is directed toward intermediate undergraduate students of the ecological sciences…

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

    ERIC Educational Resources Information Center

    Stevenson, R. D.

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

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

    ERIC Educational Resources Information Center

    Cowan, Christina E.

    This module is part of a series designed to be used by life science students for instruction in the application of physical theory to ecosystem operation. Most modules contain computer programs which are built around a particular application of a physical process. This module deals specifically with concepts that are basic to fluid flow and…

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

    ERIC Educational Resources Information Center

    Anderson, Lougenia; Gales, Larry

    This module is part of a series designed to be used by life science students for instruction in the application of physical theory to ecosystem operation. Most modules contain computer programs which are built around a particular application of a physical process. FFORM is a portable format-free input subroutine package written in ANSI Fortran IV…

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

    ERIC Educational Resources Information Center

    Gates, David M.

    These materials were designed to be used by life science students for instruction in the application of physical theory to ecosystem operation. Most modules contain computer programs which are built around a particular application of a physical process. This report introduces two models of the thermal energy budget of a leaf. Typical values for…

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

    ERIC Educational Resources Information Center

    Levin, Michael; Gallucci, V. F.

    These materials were designed to be used by life science students for instruction in the application of physical theory to ecosystem operation. Most modules contain computer programs which are built around a particular application of a physical process. This module describes the application of irreversible thermodynamics to biology. It begins with…

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

    ERIC Educational Resources Information Center

    Hertzberg, Richard C.

    This module is part of a series designed to be used by life science students for instruction in the application of physical theory to ecosystem operation. Most modules contain computer programs which are built around a particular application of a physical process. This module is used to introduce the biology student to differential calculus, a…

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

    ERIC Educational Resources Information Center

    Simpson, James R.

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

  8. Significant runoff exports of particulate nitrogen (PN) with large tropical storms: Implications of climate variability for watersheds and aquatic ecosystems

    NASA Astrophysics Data System (ADS)

    Inamdar, S. P.; Dhillon, G.

    2014-12-01

    Nitrogen (N) is an important nutrient that contributes to eutrophication of water bodies and plays a key role in various terrestrial and aquatic ecosystem processes. Thus, understanding the amounts and timing of N inputs from watersheds to aquatic ecosystems is critical. Most research to date has focused on the dissolved forms (< 0.45 micron) of N such as nitrate-N and organic N, which constitute a major portion of the N flux during baseflow and small to moderate storm events. The amounts of particulate N (PN > 0.45 micron) in runoff, can however, increase dramatically with large storms such as those associated with tropical depressions and hurricanes and can have a lasting impact on downstream aquatic systems. We determined the exports and storm-event patterns of PN for two (12 and 79 ha) intensively instrumented, headwater, forested, catchments located in the Piedmont Region of Maryland. Stream runoff sampling has been performed for baseflow and storm events since 2011 and has included numerous large tropical storms including Irene (2011) and Sandy (2012). Key questions that we address are: How significant is the PN flux, i.e., what proportion of the annual N is exported as PN during the large tropical events? How does PN export vary with storm magnitude? How do PN exports change with catchment scale? What are the temporal patterns of dissolved and particulate N species during the largest storms? Observations for tropical storm Irene (2011) revealed that in just 59 hours this storm contributed to one-third of the annual (2011) N flux from the 12 ha watershed and 87% of this N was in particulate form. A large portion of this particulate N is likely deposited in the fluvial network, especially in headwater reaches, and could potentially become bioavailable. Understanding these contributions from large events is especially important considering that climate-change scenarios indicate increased intensity of hurricanes and tropical storms and thus potentially a greater

  9. Methane turnover and methanotrophic communities in arctic aquatic ecosystems of the Lena Delta, Northeast Siberia.

    PubMed

    Osudar, Roman; Liebner, Susanne; Alawi, Mashal; Yang, Sizhong; Bussmann, Ingeborg; Wagner, Dirk

    2016-08-01

    Large amounts of organic carbon are stored in Arctic permafrost environments, and microbial activity can potentially mineralize this carbon into methane, a potent greenhouse gas. In this study, we assessed the methane budget, the bacterial methane oxidation (MOX) and the underlying environmental controls of arctic lake systems, which represent substantial sources of methane. Five lake systems located on Samoylov Island (Lena Delta, Siberia) and the connected river sites were analyzed using radiotracers to estimate the MOX rates, and molecular biology methods to characterize the abundance and the community composition of methane-oxidizing bacteria (MOB). In contrast to the river, the lake systems had high variation in the methane concentrations, the abundance and composition of the MOB communities, and consequently, the MOX rates. The highest methane concentrations and the highest MOX rates were detected in the lake outlets and in a lake complex in a flood plain area. Though, in all aquatic systems, we detected both, Type I and II MOB, in lake systems, we observed a higher diversity including MOB, typical of the soil environments. The inoculation of soil MOB into the aquatic systems, resulting from permafrost thawing, might be an additional factor controlling the MOB community composition and potentially methanotrophic capacity. PMID:27230921

  10. Removal of terrestrial dissolved organic carbon in aquatic ecosystems of a temperate river network.

    NASA Astrophysics Data System (ADS)

    Wollheim, W. M.; Stewart, R. J.; Aiken, G.; Butler, K. D.; Morse, N.; Salisbury, J.

    2015-12-01

    Surface waters play an important role in the global carbon balance. Dissolved organic carbon (DOC) fluxes are a major transfer of terrestrial carbon to river systems, and the net removal of terrestrial DOC in aquatic systems is poorly constrained. We used a combination of spatially distributed sampling of three DOC fractions, nitrate, and chloride in streams of different size throughout a river network and modeling to quantify the net removal of terrestrial DOC relative to other constituents during a summer base flow period. The approach was applied to the 400 km2 Ipswich River watershed, MA, USA. We found that aquatic reactivity of terrestrial DOC leading to net loss is low, closer to conservative chloride than to reactive nitrogen. Net removal of DOC occurred mainly from the hydrophobic organic acid fraction, while hydrophilic and transphilic acids showed no net change. Model fits were improved using the different DOC fractions than when using bulk DOC, indicating that partitioning of bulk DOC into different fractions is critical for understanding terrestrial DOC removal. These findings suggest that river systems may have only a modest ability to alter the amounts of terrestrial DOC delivered to coastal zones.

  11. Balanced nitrogen economy as a flexible strategy on yield stabilizing and quality of aquatic food crops in wetland ecosystem.

    PubMed

    Puste, A M; Sarkar, P K; Das, D K

    2005-12-01

    In wetland ecosystem, nitrogen along with other elements and its management is most imperative for the production of so many aquatic food, non-food and beneficial medicinal plants and for the improvement of soil and water characteristics. With great significant importance of INM (integrated nutrient management) as sources, emphasizing on management on nitrogen as a key element and its divergence, a case study was undertaken on such aquatic food crops (starch and protein-rich, most popular and remunerative) in the farmers' field of low-lying 'Tal' situation of New Alluvial Zone of Indian subtropics. The study was designed in factorial randomized block design, where, three important aquatic food crops (water chestnut (Trapa bispinosa Roxb.), makhana (Euryale ferox Salisb.) and water lily (Nymphaea spp.) as major factor and eleven combinations of organic and inorganic sources of nutrients as sub-factor was considered in the experiment. It revealed from the results that the production of fresh kernels or nuts of water chestnut (8.57 t ha(-1)), matured nut yield of makhana (3.06 t ha(-1)) and flower stalks of water-lily as vegetables (6.38 t ha(-1)) including its nutritional quality (starch, protein, sugar and minerals) was remarkably influenced with the application of both organic (neem oilcake @ 0.2 t ha(-1)) and inorganic sources (NPK @ 30:20:20 kg ha(-1) along with spraying of NPK @ 0.5% each over crop canopy at 20 days interval after transplanting) than the other INM combinations applied to the crops. Among the crops, highest WCYE (water chestnut yield equivalence) exhibited in makhana due to its high price of popped-form in the country, which is being exported to other countries at now. Sole application of both (organic and inorganic sources) with lower range did not produce any significant outcome from the study and exhibited lower value for all the crops. Besides production of food crops, INM also greatly influenced the soil and water characterization and it was

  12. Balanced nitrogen economy as a flexible strategy on yield stabilizing and quality of aquatic food crops in wetland ecosystem.

    PubMed

    Puste, A M; Sarkar, P K; Das, D K

    2005-09-01

    In wetland ecosystem, nitrogen along with other elements and its management is most imperative for the production of so many aquatic food, non-food and beneficial medicinal plants and for the improvement of soil and water characteristics. With great significant importance of INM (integrated nutrient management) as sources, emphasizing on management on nitrogen as a key element and its divergence, a case study was undertaken on such aquatic food crops (starch and protein-rich, most popular and remunerative) in the farmers' field of low-lying 'Tal' situation of New Alluvial Zone of Indian subtropics. The study was designed in factorial randomized block design, where, three important aquatic food crops (water chestnut (Trapa bispinosa Roxb.), makhana (Euryale ferox Salisb.) and water lily (Nymphaea spp.) as major factor and eleven combinations of organic and inorganic sources of nutrients as sub-factor was considered in the experiment. It revealed from the results that the production of fresh kernels or nuts of water chestnut (8.57 t ha(-1)), matured nut yield of makhana (3.06 t ha(-1)) and flower stalks of water-lily as vegetables (6.38 t ha(-1)) including its nutritional quality (starch, protein, sugar and minerals) was remarkably influenced with the application of both organic (neem oilcake @ 0.2 t ha(-1)) and inorganic sources (NPK @ 30:20:20 kg ha(-1) along with spraying of NPK @ 0.5% each over crop canopy at 20 days interval after transplanting) than the other INM combinations applied to the crops. Among the crops, highest WCYE (water chestnut yield equivalence) exhibited in makhana due to its high price of popped-form in the country, which is being exported to other countries at now. Sole application of both (organic and inorganic sources) with lower range did not produce any significant outcome from the study and exhibited lower value for all the crops. Besides production of food crops, INM also greatly influenced the soil and water characterization and it was

  13. Novel use of cavity ring-down spectroscopy to investigate aquatic carbon cycling from microbial to ecosystem scales.

    PubMed

    Maher, Damien T; Santos, Isaac R; Leuven, Jasper R F W; Oakes, Joanne M; Erler, Dirk V; Carvalho, Matheus C; Eyre, Bradley D

    2013-11-19

    Development of cavity ring-down spectroscopy (CRDS) has enabled real-time monitoring of carbon stable isotope ratios of carbon dioxide and methane in air. Here we demonstrate that CRDS can be adapted to assess aquatic carbon cycling processes from microbial to ecosystem scales. We first measured in situ isotopologue concentrations of dissolved CO2 ((12)CO2 and (13)CO2) and CH4 ((12)CH4 and (13)CH4) with CRDS via a closed loop gas equilibration device during a survey along an estuary and during a 40 h time series in a mangrove creek (ecosystem scale). A similar system was also connected to an in situ benthic chamber in a seagrass bed (community scale). Finally, a pulse-chase isotope enrichment experiment was conducted by measuring real-time release of (13)CO2 after addition of (13)C enriched phytoplankton to exposed intertidal sediments (microbial scale). Miller-Tans plots revealed complex transformation pathways and distinct isotopic source values of CO2 and CH4. Calculations of δ(13)C-DIC based on CRDS measured δ(13)C-CO2 and published fractionation factors were in excellent agreement with measured δ(13)C-DIC using isotope ratio mass spectroscopy (IRMS). The portable CRDS instrumentation used here can obtain real-time, high precision, continuous greenhouse gas data in lakes, rivers, estuaries and marine waters with less effort than conventional laboratory-based techniques. PMID:24131451

  14. Managing the effects of multiple stressors on aquatic ecosystems under water scarcity. The GLOBAQUA project.

    PubMed

    Navarro-Ortega, Alícia; Acuña, Vicenç; Bellin, Alberto; Burek, Peter; Cassiani, Giorgio; Choukr-Allah, Redouane; Dolédec, Sylvain; Elosegi, Arturo; Ferrari, Federico; Ginebreda, Antoni; Grathwohl, Peter; Jones, Colin; Rault, Philippe Ker; Kok, Kasper; Koundouri, Phoebe; Ludwig, Ralf Peter; Merz, Ralf; Milacic, Radmila; Muñoz, Isabel; Nikulin, Grigory; Paniconi, Claudio; Paunović, Momir; Petrovic, Mira; Sabater, Laia; Sabaterb, Sergi; Skoulikidis, Nikolaos Th; Slob, Adriaan; Teutsch, Georg; Voulvoulis, Nikolaos; Barceló, Damià

    2015-01-15

    Water scarcity is a serious environmental problem in many European regions, and will likely increase in the near future as a consequence of increased abstraction and climate change. Water scarcity exacerbates the effects of multiple stressors, and thus results in decreased water quality. It impacts river ecosystems, threatens the services they provide, and it will force managers and policy-makers to change their current practices. The EU-FP7 project GLOBAQUA aims at identifying the prevalence, interaction and linkages between stressors, and to assess their effects on the chemical and ecological status of freshwater ecosystems in order to improve water management practice and policies. GLOBAQUA assembles a multidisciplinary team of 21 European plus 2 non-European scientific institutions, as well as water authorities and river basin managers. The project includes experts in hydrology, chemistry, biology, geomorphology, modelling, socio-economics, governance science, knowledge brokerage, and policy advocacy. GLOBAQUA studies six river basins (Ebro, Adige, Sava, Evrotas, Anglian and Souss Massa) affected by water scarcity, and aims to answer the following questions: how does water scarcity interact with other existing stressors in the study river basins? How will these interactions change according to the different scenarios of future global change? Which will be the foreseeable consequences for river ecosystems? How will these in turn affect the services the ecosystems provide? How should management and policies be adapted to minimise the ecological, economic and societal consequences? These questions will be approached by combining data-mining, field- and laboratory-based research, and modelling. Here, we outline the general structure of the project and the activities to be conducted within the fourteen work-packages of GLOBAQUA. PMID:25005236

  15. Managing the effects of multiple stressors on aquatic ecosystems under water scarcity. The GLOBAQUA project

    PubMed Central

    Navarro-Ortega, Alícia; Acuña, Vicenç; Bellin, Alberto; Burek, Peter; Cassiani, Giorgio; Choukr-Allah, Redouane; Dolédec, Sylvain; Elosegi, Arturo; Ferrari, Federico; Ginebreda, Antoni; Grathwohl, Peter; Jones, Colin; Rault, Philippe Ker; Kok, Kasper; Koundouri, Phoebe; Ludwig, Ralf Peter; Merz, Ralf; Milacic, Radmila; Muñoz, Isabel; Nikulin, Grigory; Paniconi, Claudio; Paunović, Momir; Petrovic, Mira; Sabater, Laia; Sabaterb, Sergi; Skoulikidis, Nikolaos Th.; Slob, Adriaan; Teutsch, Georg; Voulvoulis, Nikolaos; Barceló, Damià

    2015-01-01

    Water scarcity is a serious environmental problem in many European regions, and will likely increase in the near future as a consequence of increased abstraction and climate change. Water scarcity exacerbates the effects of multiple stressors, and thus results in decreased water quality. It impacts river ecosystems, threatens the services they provide, and it will force managers and policy-makers to change their current practices. The EU-FP7 project GLOBAQUA aims at identifying the prevalence, interaction and linkages between stressors, and to assess their effects on the chemical and ecological status of freshwater ecosystems in order to improve water management practice and policies. GLOBAQUA assembles a multidisciplinary team of 21 European plus 2 non-European scientific institutions, as well as water authorities and river basin managers. The project includes experts in hydrology, chemistry, biology, geomorphology, modelling, socio-economics, governance science, knowledge brokerage, and policy advocacy. GLOBAQUA studies six river basins (Ebro, Adige, Sava, Evrotas, Anglian and Souss Massa) affected by water scarcity, and aims to answer the following questions: how does water scarcity interact with other existing stressors in the study river basins? How will these interactions change according to the different scenarios of future global change? Which will be the foreseeable consequences for river ecosystems? How will these in turn affect the services the ecosystems provide? How should management and policies be adapted to minimise the ecological, economic and societal consequences? These questions will be approached by combining data-mining, field- and laboratory-based research, and modelling. Here, we outline the general structure of the project and the activities to be conducted within the fourteen work-packages of GLOBAQUA. PMID:25005236

  16. Effects of municipal wastewater on aquatic ecosystem structure and function in the receiving stream.

    PubMed

    Englert, Dominic; Zubrod, Jochen P; Schulz, Ralf; Bundschuh, Mirco

    2013-06-01

    During recent years, increasing incidences of summer droughts - likely driven by climate change - reduced the dilution potential of low-order streams for secondary treated wastewater also in temperate Europe. Despite the potential risks to ecosystem integrity, there is a paucity of knowledge regarding the effects of different wastewater dilution potentials on ecosystem functions. The present study investigated the implications of secondary treated wastewater released into a third-order stream (Queich, southwest Germany) during a season with low dilution potential (summer; ~90% wastewater) as compared to a season with high dilution potential (winter; ~35% wastewater) in terms of leaf litter decomposition and macroinvertebrate communities. Adverse effects in macroinvertebrate mediated leaf mass loss (~65%), gammarids' feeding rate (~80%), leaf associated fungal biomass (>40%) and shifts in macroinvertebrate community structure were apparent up to 100 and 300 m (partially 500 m) downstream of the wastewater treatment plant effluent during winter and summer, respectively. In addition, a Gammarus fossarum laboratory feeding trial demonstrated the potential of powdered activated carbon to reduce the ecotoxicity of released wastewater. These results urge the development and evaluation of adequate management strategies, e.g. the application of advanced wastewater treatment technologies, to protect the integrity of freshwater ecosystems, which is required by the European Water Framework Directive - also considering decreasing dilution potential of streams as projected by climate change scenarios. PMID:23562693

  17. Processes influencing chemical biomagnification and trophic magnification factors in aquatic ecosystems: Implications for chemical hazard and risk assessment.

    PubMed

    Mackay, Donald; Celsie, Alena K D; Arnot, Jon A; Powell, David E

    2016-07-01

    Bioconcentration factors (BCFs) and bioaccumulation factors (BAFs) are widely used in scientific and regulatory programs to assess chemical hazards. There is increasing interest in also using biomagnification factors (BMFs) and trophic magnification factors (TMFs) for this purpose, especially for highly hydrophobic substances that may reach high concentrations in predatory species that occupy high trophic level positions in ecosystems. Measurements of TMFs in specific ecosystems can provide invaluable confirmation that biomagnification or biodilution has occurred across food webs, but their use in a regulatory context can be controversial because of uncertainties related to the reliability of measurements and their regulatory interpretation. The objective of this study is to explore some of the recognized uncertainties and dependencies in field BMFs and TMFs. This is accomplished by compiling a set of three simple food web models (pelagic, demersal and combined pelagic-demersal) consisting of up to seven species to simulate field BMFs and TMFs and to explore their dependences on hydrophobicity (expressed as log KOW), rates of biotransformation and growth, sediment-water fugacity ratios, and extent of food web omnivory and issues that arise when chemical concentration gradients exist in aquatic ecosystems. It is shown that empirical TMFs can be highly sensitive to these factors, thus the use of TMFs in a regulatory context must recognize these sensitivities. It is suggested that simple but realistic evaluative food web models could be used to extend BCF and BAF assessments to include BMFs and TMFs, thus providing a tool to address bioaccumulation hazard and the potential risk of exposures to elevated chemical concentrations in organisms at high trophic levels. PMID:27038905

  18. Cyanobacteria and Cyanotoxins: From Impacts on Aquatic Ecosystems and Human Health to Anticarcinogenic Effects

    PubMed Central

    Zanchett, Giliane; Oliveira-Filho, Eduardo C.

    2013-01-01

    Cyanobacteria or blue-green algae are among the pioneer organisms of planet Earth. They developed an efficient photosynthetic capacity and played a significant role in the evolution of the early atmosphere. Essential for the development and evolution of species, they proliferate easily in aquatic environments, primarily due to human activities. Eutrophic environments are conducive to the appearance of cyanobacterial blooms that not only affect water quality, but also produce highly toxic metabolites. Poisoning and serious chronic effects in humans, such as cancer, have been described. On the other hand, many cyanobacterial genera have been studied for their toxins with anticancer potential in human cell lines, generating promising results for future research toward controlling human adenocarcinomas. This review presents the knowledge that has evolved on the topic of toxins produced by cyanobacteria, ranging from their negative impacts to their benefits. PMID:24152991

  19. Cyanobacteria and cyanotoxins: from impacts on aquatic ecosystems and human health to anticarcinogenic effects.

    PubMed

    Zanchett, Giliane; Oliveira-Filho, Eduardo C

    2013-10-01

    Cyanobacteria or blue-green algae are among the pioneer organisms of planet Earth. They developed an efficient photosynthetic capacity and played a significant role in the evolution of the early atmosphere. Essential for the development and evolution of species, they proliferate easily in aquatic environments, primarily due to human activities. Eutrophic environments are conducive to the appearance of cyanobacterial blooms that not only affect water quality, but also produce highly toxic metabolites. Poisoning and serious chronic effects in humans, such as cancer, have been described. On the other hand, many cyanobacterial genera have been studied for their toxins with anticancer potential in human cell lines, generating promising results for future research toward controlling human adenocarcinomas. This review presents the knowledge that has evolved on the topic of toxins produced by cyanobacteria, ranging from their negative impacts to their benefits. PMID:24152991

  20. Distribution and bioavailability of ceria nanoparticles in an aquatic ecosystem model.

    PubMed

    Zhang, Peng; He, Xiao; Ma, Yuhui; Lu, Kai; Zhao, Yuliang; Zhang, Zhiyong

    2012-10-01

    Along with the increasing utilization of engineered nanoparticles, there is a growing concern for the potential environmental and health effects of exposure to these newly designed materials. Understanding the behavior of nanoparticles in the environment is a basic need. The present study aims to investigate the distribution and fate of ceria nanoparticles in an aquatic system model which consists of sediments, water, hornworts, fish and snails, using a radiotracer technique. Concentrations of ceria in the samples at regular time intervals were measured. Ceria nanoparticles were readily removed from the water column and partitioned between different organisms. Both snail and fish have fast absorption and clearance abilities. Hornwort has the highest bioaccumulation factors. At the end of the experiment, sediments accumulated most of the nanoparticles with a recovery of 75.7 ± 27.3% of total ceria nanoparticles, suggesting that sediments are major sinks of ceria nanoparticles. PMID:22694776

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

    SciTech Connect

    Cummins, C.L.

    1994-09-01

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

  2. Changing seasonality of Arctic hydrology disrupts key biotic linkages in Arctic aquatic ecosystems.

    NASA Astrophysics Data System (ADS)

    Deegan, L.; MacKenzie, C.; Peterson, B. J.; Fishscape Project

    2011-12-01

    Arctic grayling (Thymallus arcticus) is an important circumpolar species that provide a model system for understanding the impacts of changing seasonality on arctic ecosystem function. Grayling serve as food for other biota, including lake trout, birds and humans, and act as top-down controls in stream ecosystems. In Arctic tundra streams, grayling spend their summers in streams but are obligated to move back into deep overwintering lakes in the fall. Climatic change that affects the seasonality of river hydrology could have a significant impact on grayling populations: grayling may leave overwintering lakes sooner in the spring and return later in the fall due to a longer open water season, but the migration could be disrupted by drought due to increased variability in discharge. In turn, a shorter overwintering season may impact lake trout dynamics in the lakes, which may rely on the seasonal inputs of stream nutrients in the form of migrating grayling into these oligotrophic lakes. To assess how shifting seasonality of Arctic river hydrology may disrupt key trophic linkages within and between lake and stream components of watersheds on the North Slope of the Brooks Mountain Range, Alaska, we have undertaken new work on grayling and lake trout population and food web dynamics. We use Passive Integrated Transponder (PIT) tags coupled with stream-width antenna units to monitor grayling movement across Arctic tundra watersheds during the summer, and into overwintering habitat in the fall. Results indicate that day length may prime grayling migration readiness, but that flooding events are likely the cue grayling use to initiate migration in to overwintering lakes. Many fish used high discharge events in the stream as an opportunity to move into lakes. Stream and lake derived stable isotopes also indicate that lake trout rely on these seasonally transported inputs of stream nutrients for growth. Thus, changes in the seasonality of river hydrology may have broader

  3. Mercury cycling in aquatic ecosystems and trophic state-related variables--implications from structural equation modeling.

    PubMed

    Pollman, Curtis D

    2014-11-15

    Structural equation modeling (SEM) provides a framework that can more properly handle complex variable interactions inherent in mercury cycling and its bioaccumulation compared to more traditional regression-based methods. SEM was applied to regional data sets for three different types of aquatic ecosystems within Florida, USA--lakes, streams, and the Everglades--to evaluate the underlying nature (i.e., indirect and direct) of the relationships between fish mercury concentrations and trophic state related variables such as nutrients, dissolved organic carbon (DOC), sulfate, and alkalinity. The modeling results indicated some differences in key variable relationships--for example, the effect of nutrients on fish mercury in lakes and streams was uniformly negative through direct and indirect pathways consistent with biodilution or eutrophication-associated effects on food web structure. Somewhat surprisingly, however, was that total phosphorus did not serve as a meaningful variable in the Everglades model, apparently because its effects were masked or secondary to the effects of DOC. What is perhaps a more important result were two key similarities across the three systems. First, the modeling clearly indicates that the dominant influence on fish tissue mercury concentrations in all three systems is related to variations in the methylmercury signal. Second, the modeling demonstrated that the effect of DOC on fish mercury concentrations was exerted through multiple and antagonistic pathways, including facilitated transport of total mercury and methylmercury, enhanced rates of methylation, and limitations imposed on bioavailability. Indeed, while the individual DOC pathways in the models were all highly significant (generally p<0.001), the net effect of DOC in each model was greatly reduced or insignificant. These results can help explain contradictory results obtained previously by other researchers in other systems, and illustrate the importance of SEM as a modeling

  4. C.E.B.A.S. mini module: Test results of an artificial (man-made) aquatic ecosystem

    NASA Astrophysics Data System (ADS)

    Blüm, V.; Kreuzberg, K.; Stretzke, E.

    1994-11-01

    The original Closed Equilibrated Biological Aquatic System (C.E.B.A.S.) is a long-term multi-generation research facility for experiments with aquatic animals and plants in a space station the development of which is surrounded by a large international scientific program. In addition, a miniaturized laboratory prototype, the C.E.B.A.S. MINI MODULE, with a total volume of about 10 - 12 liters for a Spacelab middeck locker was developed and a first version was tested successfully for two weeks with a population of fishes (Xiphophorus helleri) in the animal tank and a Ceratophyllum spec. in the illuminated higher plant growth chamber. The water recycling system consisted of a bacteria filter and a mechanical filter and the silastic tubing gas exchanger was separated by valves for the utilization in emergency cases only. Data were collected with the acquisition module of the original C.E.B.A.S. process control system. In addition, an optimized version was tested for 7 weeks with fishes and plants and thereafter with fish and with plants only for 2 and 1 weeks, resp.. The paper presents the relevant water parameters (e. g., pH, pressure, temperature, oxygen saturation, flow rate, ion concentrations) during the test period as well as morphological and physiological data of the enclosed animals and plants. On the basis of the given results the possible role of the C.E.B.A.S. system as a scientific tool in artificial ecosystem research and for the development of a combined animal-plant intensive aquaculture system and its utilization in bioregenerative life support is discussed.

  5. Environmental effects of dredging: Trophic transfer and biomagnification potential of contaminants in aquatic ecosystems. Technical notes

    SciTech Connect

    Dillon, T.M.; Suedel, B.C.; Peddicord, R.K.; Clifford, P.A.; Boraczek, J.A.

    1995-01-01

    The terms bioconcentration, bioaccumulation, biomagnification, trophic transfer, and trophic transfer coefficient are defined to avoid confusion, as they have been used inconsistently throughout the literature (Dallinger and others 1987). Bioconcentration is the uptake of a contaminant by aquatic organisms where water is the sole containment source. Bioaccumulation is the uptake of a contaminent from both water and dietary sources. Biomagnification refers to the processes of both bioconcentration and bioaccumulation that result in increased tissue concentrations of a contaminant as it passes through two or more trophic levels (Macek, Petrocelli, and Sleight 1979). Trophic transfer is defined as the transport of contaminants between two trophic levels (that is, prey to predator) (Swartz and Lee 1980). Trophic transfer coefficient (FTC) is the concentration of contaminant in consumer tissue divided by the concentration of contaminant in food sources (that is, preceding trophic level). A TTC is an approximate measure of the potential for a contaminant to biomagnify. Biomagnification occurs when concentrations of a material increase between two or more trophic levels (that is, TTC>1) and is a sub- set of trophic transfer, which refers to any movement of a material between trophic levels (that is, TTC can be greater than or less than 1). If trophic transfer is determined to be substantially >1, biomagnification is said to occur. If a TTC value is <1%, biomagnification is judged not to take place.

  6. Environmental control of diatom community size structure varies across aquatic ecosystems

    PubMed Central

    Finkel, Zoe V.; Vaillancourt, Colin Jacob; Irwin, Andrew J.; Reavie, Euan D.; Smol, John P.

    2009-01-01

    Changes in the size structure of photoautotrophs influence food web structure and the biogeochemical cycling of carbon. Decreases in the median size of diatoms within communities, in concert with climate warming and water column stratification, have been observed over the Cenozoic in the ocean and over the last 50 years in Lake Tahoe. Decreases in the proportion of larger plankton are frequently observed in response to reduced concentrations of limiting nutrients in marine systems and large stratified lakes. By contrast, we show a decrease in the median size of planktonic diatoms in response to higher nutrient concentrations in a set of intermediate-sized alkaline lakes. Climate-induced increases in the frequency, duration and strength of water column stratification may select smaller planktonic species in the ocean and larger lakes owing to a reduction in nutrient availability and sinking rates, while light limitation, stimulated by nutrient eutrophication and high chlorophyll concentrations, may select smaller species within a community owing to their high light absorption efficiencies and lower sinking rates. The relative importance of different physiological and ecological rates and processes on the size structure of communities varies in different aquatic systems owing to varying combinations of abiotic and biotic constraints. PMID:19203916

  7. Bioaccumulation of PCBs in aquatic biota from a tidal freshwater marsh ecosystem.

    PubMed

    Crimmins, B S; Brown, P Doelling; Kelso, D P; Foster, G D

    2002-05-01

    Water, sediments, and aquatic biota were sampled in a tidal river-marsh on the Potomac River near Washington, DC (USA) to assess baseline concentrations of polychlorinated biphenyls (PCBs) and bioaccumulation in finish species. The mean sediment total-PCB concentration in the wetland was 50 ng/g dry weight, and mean concentrations in biota ranged from 150 ng/g to 450 ng/g wet weight. The highest PCB concentrations were observed in channel catfish. The median biota-sediment accumulation factor (BSAF) estimated in all finfish species for total-PCBs was 2.9. However, some of the individual and co-eluting PCB congeners had median BSAFs that were substantially greater (e.g., congener numbers 42, 74, 182/187/128, and 171) or lower (e.g., congener numbers 18/15, 45, 185, and 208) than the total-PCB average. Apparent bioaccumulation factors (biota/water PCB concentration ratios) for PCB congeners showed a parabolic relation with n-octanol/water partition coefficients, confirming some previous investigations. There was no clear trend between apparent bioaccumulation factors and trophic level. Organic-carbon-normalized sediment distribution constants (sediment/water PCB concentration ratios) were linearly related to the apparent bioaccumulation factors for all the finfish species investigated. PMID:11994779

  8. An adaptive, comprehensive monitoring strategy for chemicals of emerging concern (CECs) in California's Aquatic Ecosystems.

    PubMed

    Maruya, Keith A; Schlenk, Daniel; Anderson, Paul D; Denslow, Nancy D; Drewes, Jörg E; Olivieri, Adam W; Scott, Geoffrey I; Snyder, Shane A

    2014-01-01

    A scientific advisory panel was convened by the State of California to recommend monitoring for chemicals of emerging concern (CECs) in aquatic systems that receive discharge of municipal wastewater treatment plant (WWTP) effluent and stormwater runoff. The panel developed a risk-based screening framework that considered environmental sources and fate of CECs observed in receiving waters across the State. Using existing occurrence and risk threshold data in water, sediment, and biological tissue, the panel applied the framework to identify a priority list of CECs for initial monitoring in three representative receiving water scenarios. The initial screening list of 16 CECs identified by the panel included consumer and commercial chemicals, flame retardants, pesticides, pharmaceuticals and personal care products, and natural hormones. The panel designed an iterative, phased strategy with interpretive guidelines that direct and update management actions commensurate with potential risk identified using the risk-based framework and monitoring data. Because of the ever-changing nature of chemical use, technology, and management practices, the panel offered recommendations to improve CEC monitoring, including development of bioanalytical screening methods whose responses integrate exposure to complex mixtures and that can be linked to higher-order effects; development or refinement of models that predict the input, fate, and effects of future chemicals; and filling of key data gaps on CEC occurrence and toxicity. Finally, the panel stressed the need for adaptive management, allowing for future review of, and if warranted, modifications to the strategy to incorporate the latest science available to the water resources community. PMID:24129960

  9. Comparison of Carbon Sequestration Rates and Energy Balance of Turf in the Denver Urban Ecosystem and an Adjacent Native Grassland

    NASA Astrophysics Data System (ADS)

    Thienelt, T. S.; Anderson, D. E.; Powell, K. M.

    2011-12-01

    Urban ecosystems are currently characterized by rapid growth, are expected to continually expand and, thus, represent an important driver of land use change. A significant component of urban ecosystems is lawns, potentially the single largest irrigated "crop" in the U.S. Beginning in March of 2011 (ahead of the growing season), eddy covariance measurements of net carbon exchange and evapotranspiration along with energy balance fluxes were conducted for a well-watered, fertilized lawn (rye-bluegrass-mix) in metropolitan Denver and for a nearby tallgrass prairie (big bluestem, switchgrass, cheatgrass, blue grama). Due to the semi-arid climate conditions of the Denver region, differences in management (i.e., irrigation and fertilization) are expected to have a discernible impact on ecosystem productivity and thus on carbon sequestration rates, evapotranspiration, and the sensible and latent heat partitioning of the energy balance. By mid-July, preliminary data indicated that cumulative evapotranspiration was approximately 270 mm and 170 mm for urban and native grasslands, respectively, although cumulative carbon sequestration at that time was similar for both (approximately 40 mg/m2). However, the pattern of carbon exchange differed between the grasslands. Both sites showed daily net uptake of carbon starting in late May, but the urban lawn displayed greater diurnal variability as well as greater uptake rates in general, especially following fertilization in mid-June. In contrast, the trend of carbon uptake at the prairie site was occasionally reversed following strong convective precipitation events, resulting in a temporary net release of carbon. The continuing acquisition of data and investigation of these relations will help us assess the potential impact of urban growth on regional carbon sequestration.

  10. The Economic Value of the Greater Montreal Blue Network (Quebec, Canada): A Contingent Choice Study Using Real Projects to Estimate Non-Market Aquatic Ecosystem Services Benefits.

    PubMed

    Poder, Thomas G; Dupras, Jérôme; Fetue Ndefo, Franck; He, Jie

    2016-01-01

    This study used a contingent choice method to determine the economic value of improving various ecosystem services (ESs) of the Blue Network of Greater Montreal (Quebec, Canada). Three real projects were used and the evaluation focused on six ESs that are related to freshwater aquatic ecosystems: biodiversity, water quality, carbon sequestration, recreational activities, landscape aesthetics and education services. We also estimated the value associated with the superficies of restored sites. We calculated the monetary value that a household would be willing to pay for each additional qualitative or quantitative unit of different ESs, and these marginal values range from $0.11 to $15.39 per household per unit. Thus, under certain assumptions, we determined the monetary values that all Quebec households would allocate to improve each ES in Greater Montreal by one unit. The most valued ES was water quality ($13.5 million), followed by education services ($10.7 million), recreational activities ($8.9 million), landscape aesthetics ($4.1 million), biodiversity ($1.2 million), and carbon sequestration ($0.1 million). Our results ascribe monetary values to improved (or degraded) aquatic ecosystems in the Blue Network of Greater Montreal, but can also enhance economic analyses of various aquatic ecosystem restoration and management projects. PMID:27513558

  11. The Economic Value of the Greater Montreal Blue Network (Quebec, Canada): A Contingent Choice Study Using Real Projects to Estimate Non-Market Aquatic Ecosystem Services Benefits

    PubMed Central

    Dupras, Jérôme; Fetue Ndefo, Franck; He, Jie

    2016-01-01

    This study used a contingent choice method to determine the economic value of improving various ecosystem services (ESs) of the Blue Network of Greater Montreal (Quebec, Canada). Three real projects were used and the evaluation focused on six ESs that are related to freshwater aquatic ecosystems: biodiversity, water quality, carbon sequestration, recreational activities, landscape aesthetics and education services. We also estimated the value associated with the superficies of restored sites. We calculated the monetary value that a household would be willing to pay for each additional qualitative or quantitative unit of different ESs, and these marginal values range from $0.11 to $15.39 per household per unit. Thus, under certain assumptions, we determined the monetary values that all Quebec households would allocate to improve each ES in Greater Montreal by one unit. The most valued ES was water quality ($13.5 million), followed by education services ($10.7 million), recreational activities ($8.9 million), landscape aesthetics ($4.1 million), biodiversity ($1.2 million), and carbon sequestration ($0.1 million). Our results ascribe monetary values to improved (or degraded) aquatic ecosystems in the Blue Network of Greater Montreal, but can also enhance economic analyses of various aquatic ecosystem restoration and management projects. PMID:27513558

  12. Effect of dumping and cleaning activities on the aquatic ecosystems of the Guadiamar River following a toxic flood.

    PubMed

    Prat, N; Toja, J; Solà, C; Burgos, M D; Plans, M; Rieradevall, M

    1999-12-01

    The main aim of the study was to document the recovery of the aquatic ecosystem after the release of toxic mining waste in the Guadiamar River Basin (Sevilla, SW Spain) in April 1998. Samples of water, plankton, periphyton and macroinvertebrates were taken once a month at nine sampling stations (six affected by the toxic release and three for control). Water hardness and pH recovered in a few weeks and did not change significantly thereafter in the river or in the marsh stations. Only the Agrio River (the tributary that received the initial waste dump) had a low pH (3-5) throughout the study period. High ammonia contents (up to 300 microM) were measured at two sampling stations due to sewage and oil mill pollution. Eutrophication was also common at most of the stations, including one reference site. The planktonic community did not differ substantially between reference and affected stations. On all occasions the small phytoplankton and zooplankton (rotifers) were dominant. Compared with the reference station, chlorophyll a in the riverine area increased, especially in the sewage-affected stations, while in the marsh area, no significant differences were found between affected and reference stations. After 6 months of cleaning operations, in November 1998 the macroinvertebrate community of the river was composed mainly of species of short life cycles typical of ponds (Heteroptera, Coleoptera and Odonata), while typical riverine species found at the upstream control station had not recolonized the river due to the transformation of the river into a series of artificial ponds constructed as sediment traps. An analysis of variance showed significantly higher values (P < 0.05) for all heavy metals analysed (Zn, Cu, Pb, As, Cd, Sb, Tl) in plankton and macroinvertebrate communities from impacted sites. Values found in invertebrates were highly variable, with a mean concentration of the most abundant metals, Zn and Cu, between two and three times those found in unpolluted

  13. Isotope tracing of Hg pollution from artisanal small scale gold mining in an aquatic ecosystem of Amapá, Brazil

    NASA Astrophysics Data System (ADS)

    Adler Miserendino, R.; Silbergeld, E. K.; Guimarães, J. D.; Ghosh, S.; Bergquist, B. A.

    2010-12-01

    Artisinal small scale gold mining (ASGM) is a central economic activity throughout the developing world. It is both a poverty driven and poverty alleviating process; however, ASGM leads to extensive pollution of waterways through the use of Hg to extract gold from deposits. There have been many studies conducted in the Amazon showing elevated levels of Hg in fish and sediment downstream of ASGM sites; however, the debate continues about the contribution of Hg from ASGM versus other potential sources of Hg. In this study, we investigate whether Hg stable isotope analysis can be used to trace mercury pollution from an ASGM site through an aquatic ecosystem in Amapá, Brazil. We measured the Hg isotopic composition of sediment cores from two lakes, only one of which was heavily impacted by the use of elemental Hg in ASGM, as well as from grab samples at the AGSM site and upstream and downstream from the AGSM site along the river which connects the polluted lake to the ASGM site. Hg from all samples were trapped via combustion using the Leeman Labs Hydra-C mercury analyzer and analyzed for both mass-independent and mass-dependent signatures using cold vapor multi-collector inductively coupled plasma mass spectrometry (CV-MC-ICP-MS). Detectable variations in the Hg isotopic signatures were apparent across our field sites, suggesting stable isotopic analysis has great potential to trace contamination pathways in waterways. Preliminary data demonstrate Hg from the ASGM site has unique isotopic signatures that are seen downstream. However, the impacted lake sediments do not have the mining signature despite having three times more Hg than the non-impacted lake. Based on this data, it may be possible to trace Hg from ASGM and assess whether it is impacting local ecosystems and food webs. Hair and soil samples will also be discussed. This demonstration is essential for the broader application of these tools for understanding and applying Hg isotopic analysis in other

  14. Comparing net ecosystem carbon dioxide exchange at adjacent commercial bioenergy and conventional cropping systems in Lincolnshire, United Kingdom

    NASA Astrophysics Data System (ADS)

    Morrison, Ross; Brooks, Milo; Evans, Jonathan; Finch, Jon; Rowe, Rebecca; Rylett, Daniel; McNamara, Niall

    2016-04-01

    The conversion of agricultural land to bioenergy plantations represents one option in the national and global effort to reduce greenhouse gas emissions whilst meeting future energy demand. Despite an increase in the area of (e.g. perennial) bioenergy crops in the United Kingdom and elsewhere, the biophysical and biogeochemical impacts of large scale conversion of arable and other land cover types to bioenergy cropping systems remain poorly characterised and uncertain. Here, the results of four years of eddy covariance (EC) flux measurements of net ecosystem CO2 exchange (NEE) obtained at a commercial farm in Lincolnshire, United Kingdom (UK) are reported. CO2 flux measurements are presented and compared for arable crops (winter wheat, oilseed rape, spring barely) and plantations of the perennial biofuel crops Miscanthus x. giganteus (C4) and short rotation coppice (SRC) willow (Salix sp.,C3). Ecosystem light and temperature response functions were used to analyse and compare temporal trends and spatial variations in NEE across the three land covers. All three crops were net in situ sinks for atmospheric CO2 but were characterised by large temporal and between site variability in NEE. Environmental and biological controls driving the spatial and temporal variations in CO2 exchange processes, as well as the influences of land management, will be analysed and discussed.

  15. Polonium, uranium and plutonium radionuclides in aquatic and land ecosystem of Poland.

    PubMed

    Skwarzec, Bogdan; Strumińska-Parulska, Dagmara I; Boryło, Alicja; Kabat, Krzysztof

    2012-01-01

    This article presents the results of study about distribution, inflow and accumulation of polonium, uranium and plutonium in aquatic and land environment of Poland and the southern Baltic Sea. Radionuclides of (210)Po, (234)U and (238)U as well as (239+240)Pu and (241)Pu are strongly accumulated in Baltic organisms and plants and transferred through the trophic chain. The values of bioconcentration factor (BCF) in Baltic plants and animals are higher for polonium and plutonium in comparison with uranium. The principal source of radionuclides in the southern Baltic Sea is their inflow with rivers. Total annual runoff of polonium, uranium and plutonium from the Vistula and the Odra as well as the Pomeranian rivers were calculated at 95 GBq of (210)Po, 750 GBq of (234+238)U and 160 MBq of (238+239+240)Pu. Seasonal and spatial variability of (210)Po, (238)U and (239+240)Pu levels in the Vistula and the Odra drainage basins were assessed by application of neural-network based classification, especially cluster analysis (CA), principal component analysis (PCA) and self-organizing maps (SOM). The result for the Vistula river indicated correlation between polonium and plutonium as well as polonium and uranium. In the Odra drainage basin, the biggest differences were observed in the case of (238)U. To assess if there are statistically significant differences in mean concentration values of (210)Po, (238)U and (239+240)Pu for the Vistula and the Odra rivers drainage basins were obtained by used of the non-parametric tests. Comparing to the Vistula catchment area, statistically differences concentration of (210)Po and (239+240)Pu in all year was observed for river samples collected on the Odra drainage basin. PMID:22320701

  16. The role of biogenic Fe-Mn oxides formed in situ for arsenic oxidation and adsorption in aquatic ecosystems.

    PubMed

    Bai, Yaohui; Yang, Tingting; Liang, Jinsong; Qu, Jiuhui

    2016-07-01

    As(III&V), Mn(II), and Fe(II) may occur simultaneously in some groundwater and surface water. Studying their redox reactions and interactions is essential to unravel the biogeochemical cycles of these metal ions in aquatic ecosystems and to find effective methods to remove them simultaneously in drinking water treatment. Here, the formation of biogenic Fe-Mn oxides (BFMO, defined as a mixture of biogenic Mn oxide (BMO) and Fe oxide) as well as its oxidation and adsorption of As in a Fe(II)-Mn(II)-As(III&V)-Mn-oxidizing microbe (Pseudomonas sp. QJX-1) system were investigated. Batch experiments and structure characterization revealed that the BFMO was formed via a sequential precipitation of Fe oxide and BMO. The first formed Fe oxide was identified as FeOOH (lepidocrocite) and the latter formed BMO was identified as MnO2 (similar to hexagonal birnessite). In the BFMO mixture, the BMO part was mainly responsible for As(III) oxidation, and the Fe oxide part dominated As adsorption. Remarkably, the BMO could oxidize Fe(II) to form FeOOH, which may improve As adsorption. The optimum Mn(II)/Fe(II) ratio for As removal was approximately 1:3 (mol/mol). Taken together, in Fe(II)-Mn(II)-As(III&V)-Mn-oxidizing microbe ecosystems, the in situ formation of BFMO could eliminate or decrease Fe(II), Mn(II), and As(III&V) species simultaneously. Therefore, based on this study, new approaches may be developed for As removal from water containing high concentrations of Fe(II) and Mn(II). PMID:27088246

  17. Impacts of acid emissions from Nevado del Ruiz volcano, Colombia, on selected terrestrial and aquatic ecosystems

    NASA Astrophysics Data System (ADS)

    Parnell, Roderic A.; Burke, Kelly J.

    1990-07-01

    Emissions of acidic gases and thermal waters from Nevado del Ruiz volcano have recently increased in concert with the November 13, 1985 eruption. This study examines the downwind and downstream effects of these emissions on alpine ecosystems high on the slopes of the volcano (4100 m) and on coffee plantations at lower elevations (< 2000 m) and greater distances from the active vent (> 30 km). Samples of bulk deposition, rain, soils, soil solutions, and streams were collected over a six-month period (January-July, 1987) to examine the impacts of this volcanogenic acidity. Bulk deposition falling on the higher slopes of the volcano is usually acidified; however, deposition reaching the distal coffee plantations seldom is acidic. The sources of the acids are hydrogen chloride and sulfur dioxide in the plume of the volcano. Although sulfur dioxide is by far the more abundant gas, hydrogen chloride is most responsible for acidification of rain falling on the slopes of the volcano. With distance from the vent, the chloride/sulfate ratio drops exponentially. The only major influence on regional precipitation chemistry in addition to the volcano appears to be land-use-related activities around the coffee plantations. Deposition on these areas is enriched by an order of magnitude in nitrate and base cations, compared to all other stations. Throughfall chemistry in the coffee plantations shows a dramatic response to occasional acid-rain events. A base-leaching process on coffee plant leaves is triggered by acid rain. For each equivalent of hydrogen ion in rain on the leaf surface, over 23 equivalents of potassium ion are leached from the leaf. In spite of this dramatic response by the vegetation, the plantation soils appear relatively unaffected by acidic deposition. In contrast, the alpine soils on the volcano exhibit low pHs, high sulfate and chloride concentrations in soil solutions, and high extractable sulfate concentrations. All of these factors indicate that these

  18. Comparisons among ten models of acoustic backscattering used in aquatic ecosystem research.

    PubMed

    Jech, J Michael; Horne, John K; Chu, Dezhang; Demer, David A; Francis, David T I; Gorska, Natalia; Jones, Benjamin; Lavery, Andone C; Stanton, Timothy K; Macaulay, Gavin J; Reeder, D Benjamin; Sawada, Kouichi

    2015-12-01

    Analytical and numerical scattering models with accompanying digital representations are used increasingly to predict acoustic backscatter by fish and zooplankton in research and ecosystem monitoring applications. Ten such models were applied to targets with simple geometric shapes and parameterized (e.g., size and material properties) to represent biological organisms such as zooplankton and fish, and their predictions of acoustic backscatter were compared to those from exact or approximate analytical models, i.e., benchmarks. These comparisons were made for a sphere, spherical shell, prolate spheroid, and finite cylinder, each with homogeneous composition. For each shape, four target boundary conditions were considered: rigid-fixed, pressure-release, gas-filled, and weakly scattering. Target strength (dB re 1 m(2)) was calculated as a function of insonifying frequency (f = 12 to 400 kHz) and angle of incidence (θ = 0° to 90°). In general, the numerical models (i.e., boundary- and finite-element) matched the benchmarks over the full range of simulation parameters. While inherent errors associated with the approximate analytical models were illustrated, so were the advantages as they are computationally efficient and in certain cases, outperformed the numerical models under conditions where the numerical models did not converge. PMID:26723330

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

    PubMed

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

    2004-09-01

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

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

    USGS Publications Warehouse

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

    2004-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Allesson, Lina; Ström, Lena; Berggren, Martin

    2016-07-01

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

  2. Trace element accumulation and trophic relationships in aquatic organisms of the Sundarbans mangrove ecosystem (Bangladesh).

    PubMed

    Borrell, Asunción; Tornero, Victoria; Bhattacharjee, Dola; Aguilar, Alex

    2016-03-01

    The Sundarbans forest is the largest and one of the most diverse and productive mangrove ecosystems in the world. Located at the northern shoreline of the Bay of Bengal in the Indian Ocean and straddling India and Bangladesh, the mangrove forest is the result of three primary river systems that originate further north and northwest. During recent decades, the Sundarbans have been subject to increasing pollution by trace elements caused by the progressive industrialization and urbanization of the basins of these three rivers. As a consequence, animals and plants dwelling downstream in the mangroves are exposed to these pollutants in varying degrees, and may potentially affect human health when consumed. The aim of the present study was to analyse the concentrations of seven trace elements (Zn, Cu, Cr, Hg, Pb, Cd and As) in 14 different animal and plant species collected in the Sundarbans in Bangladesh to study their transfer through the food web and to determine whether their levels in edible species are acceptable for human consumption. δ(15)N values were used as a proxy of the trophic level. A decrease in Zn, Cu, Pb and Cd levels was observed with increasing trophic position. Trace element concentrations measured in all organisms were, in general, lower than the concentrations obtained in other field studies conducted in the same region. When examined with respect to accepted international standards, the concentrations observed in fish and crustaceans were generally found to be safe for human consumption. However, the levels of Zn in Scylla serrata and Cr and Cd in Harpadon nehereus exceeded the proposed health advisory levels and may be of concern for human health. PMID:26748006

  3. Managing the effects of multiple stressors on aquatic ecosystems under water scarcity

    NASA Astrophysics Data System (ADS)

    Barceló Cullerés, Damià; Ludwig, Ralf

    2015-04-01

    Water and water-related services are major components of the human wellbeing, and as such are major factors of socio-economic development in Europe; yet freshwater systems are under threat by a variety of stressors (organic and inorganic pollution, geomorphological alterations, land cover change, water abstraction, invasive species and pathogens. Some stressors, such as water scarcity, can be a stressor on its own because of its structural character, and drive the effects of other stressors. The relevance of water scarcity as a stressor is more important in semi-arid regions, such as the Mediterranean basin, which are characterized by highly variable river flows and the occurrence of low flows. This has resulted in increases in frequency and magnitude of extreme flow events. Furthermore, in other European regions such as eastern Germany, western Poland and England, water demand exceeds water availability and water scarcity has become an important management issue. Water scarcity is most commonly associated with inappropriate water management, with resulting river flow reductions. It has become one of the most important drivers of change in freshwater ecosystems. Conjoint occurrence of a myriad of stressors (chemical, geomorphological, biological) under water scarcity will produce novel and unfamiliar synergies and most likely very pronounced effects. Within this context, GLOBAQUA has assembled a multidisciplinary team of leading scientists in the fields of hydrology, chemistry, ecology, ecotoxicology, economy, sociology, engineering and modeling in order to study the interaction of multiple stressors within the frame of strong pressure on water resources. The aim is to achieve a better understanding how current management practices and policies could be improved by identifying the main drawbacks and alternatives.

  4. Multispecies toxicity test for silver nanoparticles to derive hazardous concentration based on species sensitivity distribution for the protection of aquatic ecosystems.

    PubMed

    Kwak, Jin Il; Cui, Rongxue; Nam, Sun-Hwa; Kim, Shin Woong; Chae, Yooeun; An, Youn-Joo

    2016-06-01

    With increasing concerns about the release of silver nanoparticles (AgNPs) into the environment and the risks they pose to ecological and human health, a number of studies of AgNP toxicity to aquatic organisms have been conducted. USEPA and EU JRC have published risk assessment reports for AgNPs. However, most previous studies have focused on the adverse effects of AgNPs on individual species. Hazardous concentration (HC) of AgNPs for protection of aquatic ecosystems that are based on species sensitivity distributions (SSDs) have not yet been derived because sufficient data have not been available. In this study, we conducted multispecies toxicity tests, including acute assays using eight species from five different taxonomic groups (bacteria, algae, flagellates, crustaceans and fish) and chronic assays using six species from four different taxonomic groups (algae, flagellates, crustaceans and fish). Using the results of these assays, we used a SSD approach to derive an AgNP aquatic HC5 (Hazard concentrations at the 5% species) of 0.614 μg/L. To our knowledge, this is the first report of a proposed HC of AgNPs for the protection of aquatic ecosystems that is based on SSDs and uses chronic toxicity data. PMID:26634622

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

    PubMed Central

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

    2015-01-01

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

  6. Comparing the influence of wildfire and prescribed burns on watershed nitrogen biogeochemistry using 15N natural abundance in terrestrial and aquatic ecosystem components.

    PubMed

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

    2015-01-01

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

  7. Holocene Carbon Fluxes and Palaeoproductivity in Aquatic Ecosystems: a Multiproxy, Palaeolimnological Approach

    NASA Astrophysics Data System (ADS)

    Mackay, A. W.; Leng, M. J.; Morley, D. W.; Piotrowska, N.; Rioual, P.; Swann, G. E. A.

    2014-12-01

    Inland waters act as an important control on the global carbon cycle. Deep tectonic lakes may provide a key link between short-term and long-term carbon cycles as buried carbon is essentially locked away from the atmosphere over geological timescales. Here we investigate Holocene carbon dynamics in one of the worlds most important lake ecosystems, Lake Baikal, Siberia. We test the hypothesis that multiple factors play a significant role in determining long-term carbon dynamics in central Asia, and that these factors change in importance over time. Carbon isotopes (δ13C), percentage total organic carbon (%TOC) were analysed during combustion in a Carlo Erba 1500 on-line to a VG Triple Trap and dual-inlet mass spectrometer. A multi-decadal organic geochemistry record (%TOC; δ13C, C/N ratios) was determined on Holocene sediments extracted from a slope terrace c. 600 m deep. Age-depth modelling on radiocarbon-dated pollen extracts was undertaken using 'Bacon', which takes into account variable sediment accumulation rates. Carbon mass accumulation rates (CMAR; g cm-2 yr-1) were estimated at a centennial scale resolution. δ13C values were routinely higher during cool glacial periods (-26 ‰) than during warmer climates (-28 ‰) linked to changes in carbon sources. Diatom productivity & boreal forest expansion were strongly associated with δ13C variability during the early Holocene, but after 8 kyr BP, no relationships are apparent. CMAR were highest during the early Holocene (11.7 - 8 kyr BP) although rates fluctuated considerably. Peak values of 12.5 g cm-2 yr-1 were observed at 10.35 kyr BP before a rapid decline to c. 5.2 g cm-2 yr-1 at 10.05 kyr BP. CMAR declined to lowest Holocene values of 3.5 g cm-2 yr-1 by 3.9 kyr BP at the same time as maximum δ13C values (-27.0 ‰), indicative of low palaeoproductivity. Our data show that measures of palaeoproductivity in Lake Baikal are complex, and during the early Holocene are strongly associated with allochthonous

  8. Towards Sustaining Water Resources and Aquatic Ecosystems: Forecasting Watershed Risks to Current and Future Land Use Change

    NASA Astrophysics Data System (ADS)

    Lohse, K. A.; Newburn, D.; Opperman, J. J.; Brooks, C.; Merenlender, A.

    2005-05-01

    development in a watershed significantly reduced the odds of observing low embeddedness. Our 2010 forecasts highlight the sensitivity of watersheds to small changes in exurban growth. In previously unimpaired watersheds, small increases in future exurban growth resulted in cumulative impacts on substrate quality not predicted by models lacking this land use type. Because most previous analyses have characterized land use at a resolution that cannot capture exurban development, these results suggest that many such models may be missing an important type of development that can adversely impacting aquatic ecosystems. We suggest that parcel level data may be the fundamental unit for land use change analysis because it represents the economic decision unit for land owners and resolves issues of geographical scale and boundary issues that have long hampered progress in ecological forecasting.

  9. Spatial and temporal controls on Alnus-derived nutrients and stream stoichiometry: Implications for aquatic ecosystem productivity

    NASA Astrophysics Data System (ADS)

    Devotta, D.; Fraterrigo, J.; Walsh, P.; Hu, F.

    2015-12-01

    Predicting how nutrient fluxes that cross ecosystem boundaries will respond to future climate change is one of the greatest challenges for ecology in the 21st century. In southwestern (SW) Alaska, Pacific salmon (Oncorhynchus spp.) and nitrogen (N)-fixation by alder (Alnus spp.) provide key nutrient subsidies to freshwater systems. The importance of alder-derived nutrients (ADN) to aquatic systems will increase as alder cover expands under climate warming and salmon harvesting reduces marine-derived nutrients. We investigate broad-scale spatial and temporal drivers of ADN and stream N:P in 26 streams in SW Alaska. Alder cover and watershed features were measured using satellite images and topographic maps in ArcGIS. Stream water samples were collected in each spring and summer from 2010-2013 and analyzed for dissolved N and total phosphorus (TP). We obtained annual growing season length (AGSL) and sum of growing degree days (GDD) data from weather stations. Elevation was inversely related to alder cover, stream N, and N:P (ρ=-0.802, -0.65, and -0.71 resp., p<0.01, n=208). Alder cover had the largest influence on stream N (mean β estimate=0.402, 90% CIs). Stream N increased with alder cover, under longer AGSL, and lower GDD (interaction effect sizes between alder and stream N=0.196 and -0.185 resp., 90% CIs), suggesting that long growing seasons with minimal heat accumulation during the spring and fall increased ADN export. Higher P was associated with lower temperatures, possibly reflecting reduced P demand under low rates of metabolic activity. Structural equation modeling revealed significant causal relationships among elevation, alder cover, and stream N:P across multiple years (r2=0.94, X2=742.8, df=9, p<0.01). All paths in the model were significant (p<0.01) except between stream N:P and weather (p=0.165). These results demonstrate that spatial variation in alder cover associated with elevation is a stronger regulator of ADN fluxes and stream N:P than

  10. Isotopic study of mercury sources and transfer between a freshwater lake and adjacent forest food web.

    PubMed

    Kwon, Sae Yun; Blum, Joel D; Nadelhoffer, Knute J; Timothy Dvonch, J; Tsui, Martin Tsz-Ki

    2015-11-01

    Studies of monomethylmercury (MMHg) sources and biogeochemical pathways have been extensive in aquatic ecosystems, but limited in forest ecosystems. Increasing evidence suggests that there is significant mercury (Hg) exchange between aquatic and forest ecosystems. We use Hg stable isotope ratios (δ(202)Hg and Δ(199)Hg) to investigate the relative importance of MMHg sources and assess Hg transfer pathways between Douglas Lake and adjacent forests located at the University of Michigan Biological Station, USA. We characterize Hg isotopic compositions of basal resources and use linear regression of % MMHg versus δ(202)Hg and Δ(199)Hg to estimate Hg isotope values for inorganic mercury (IHg) and MMHg in the aquatic and adjacent forest food webs. In the aquatic ecosystem, we found that lake sediment represents a mixture of IHg pools deposited via watershed runoff and precipitation. The δ(202)Hg and Δ(199)Hg values estimated for IHg are consistent with other studies that measured forest floor in temperate forests. The Δ(199)Hg value estimated for MMHg in the aquatic food web indicates that MMHg is subjected to ~20% photochemical degradation prior to bioaccumulation. In the forest ecosystem, we found a significant negative relationship between total Hg and δ(202)Hg and Δ(199)Hg of soil collected at multiple distances from the lakeshore and lake sediment. This suggests that IHg input from watershed runoff provides an important Hg transfer pathway between the forest and aquatic ecosystems. We measured Δ(199)Hg values for high trophic level insects and compared these insects at multiple distances perpendicular to the lake shoreline. The Δ(199)Hg values correspond to the % canopy cover suggesting that forest MMHg is subjected to varying extents of photochemical degradation and the extent may be controlled by sunlight. Our study demonstrates that the use of Hg isotopes adds important new insight into the relative importance of MMHg sources and complex Hg transfer

  11. Seasonal dynamics of prokaryotic abundance and activities in relation to environmental parameters in a transitional aquatic ecosystem (Cape Peloro, Italy).

    PubMed

    Zaccone, R; Azzaro, M; Azzaro, F; Bergamasco, A; Caruso, G; Leonardi, M; La Ferla, R; Maimone, G; Mancuso, M; Monticelli, L S; Raffa, F; Crisafi, E

    2014-01-01

    This study examines the effects of temporal changes on microbial parameters in a brackish aquatic ecosystem. To this aim, the abundances of prokaryotes and vibrios together with the rates of enzymatic hydrolysis of proteins by leucine aminopeptidase (LAP), polysaccharides by β-glucosidase (GLU) and organic phosphates by alkaline phosphatase (AP), heterotrophic prokaryotic production (HPP), respiration (R), were seasonally investigated, during a 2-year period in the coastal area of Cape Peloro (Messina, Italy), constituted by two brackish lakes (Faro and Ganzirri). In addition, physical and chemical parameters (temperature, salinity, nutrients) and particulate organic carbon and nitrogen (POC, PN) were measured. The influence of multiple factors on prokaryotic abundances and activities was analysed. The results showed that Cape Peloro area is characterised by high seasonal variability of the microbial parameters that is higher than the spatial one. Combined changes in particulate matter and temperature (T), could explain the variability in vibrios abundance, GLU and R activities in both lakes, indicating a direct stimulation of the warm season on the heterotrophic prokaryotic metabolism. Positive correlations between T (from 13.3 to 29.6 °C) and HPP, LAP, AP, POC, PN are also observed in Ganzirri Lake. Moreover, the trophic status index and most of the microbial parameters show significant seasonal differences. This study demonstrates that vibrios abundance and microbial activities are responsive to the spatial and seasonal changes of examined area. The combined effects of temperature and trophic conditions on the microbial parameters lead us to suggest their use as potential indicators of the prokaryotic response to climate changes in temperate brackish areas. PMID:24158689

  12. Are harmful algal blooms becoming the greatest inland water quality threat to public health and aquatic ecosystems?

    PubMed

    Brooks, Bryan W; Lazorchak, James M; Howard, Meredith D A; Johnson, Mari-Vaughn V; Morton, Steve L; Perkins, Dawn A K; Reavie, Euan D; Scott, Geoffrey I; Smith, Stephanie A; Steevens, Jeffery A

    2016-01-01

    In this Focus article, the authors ask a seemingly simple question: Are harmful algal blooms (HABs) becoming the greatest inland water quality threat to public health and aquatic ecosystems? When HAB events require restrictions on fisheries, recreation, and drinking water uses of inland water bodies significant economic consequences result. Unfortunately, the magnitude, frequency, and duration of HABs in inland waters are poorly understood across spatiotemporal scales and differentially engaged among states, tribes, and territories. Harmful algal bloom impacts are not as predictable as those from conventional chemical contaminants, for which water quality assessment and management programs were primarily developed, because interactions among multiple natural and anthropogenic factors determine the likelihood and severity to which a HAB will occur in a specific water body. These forcing factors can also affect toxin production. Beyond site-specific water quality degradation caused directly by HABs, the presence of HAB toxins can negatively influence routine surface water quality monitoring, assessment, and management practices. Harmful algal blooms present significant challenges for achieving water quality protection and restoration goals when these toxins confound interpretation of monitoring results and environmental quality standards implementation efforts for other chemicals and stressors. Whether HABs presently represent the greatest threat to inland water quality is debatable, though in inland waters of developed countries they typically cause more severe acute impacts to environmental quality than conventional chemical contamination events. The authors identify several timely research needs. Environmental toxicology, environmental chemistry, and risk-assessment expertise must interface with ecologists, engineers, and public health practitioners to engage the complexities of HAB assessment and management, to address the forcing factors for HAB formation, and

  13. Aquatic Ecosystem Exposure Associated with Atmospheric Mercury Deposition: Importance of Watershed and Water Body Hot Spots and Hot Moments

    NASA Astrophysics Data System (ADS)

    Knightes, C. D.; Golden, H. E.

    2008-12-01

    Atmospheric deposition of divalent mercury (Hg(II)) is the often the primary driving force for mercury contamination in fish tissue, resulting in mercury exposure to wildlife and humans. In lake systems associated with small watersheds, direct deposition to the water surface is typically the dominant mercury loading source; however, in lake systems with large watersheds and river systems, these inputs may be relatively small compared to loadings from the watershed via erosion and surface runoff. Within each system, transformation of the deposited mercury into the environmentally relevant form, methylmercury (MeHg), proceeds at different rates largely regulated by physical characteristics such as watershed land use types and water body hydraulic residence times, as water body chemistry, such as pH and trophic status Therefore, to fully represent mercury exposure in aquatic ecosystems, we must couple watershed models with water body models and explore where, why, and when hot spots and hot moments of transformation and transport occur. Here we link the simulated atmospheric mercury deposition results from the Community Multi-Scale Air Quality (CMAQ) model, a spatially distributed grid-based watershed mercury (Hg) model (GBMM), and the Water Quality Analysis Simulation Program (WASP). We use this multi-media modeling framework to simulate mercury species cycling over time for the different river reaches and watersheds within the Cape Fear River Basin, North Carolina. Through these simulations we investigate the importance of specific watershed and surface water system characteristics in simulating MeHg exposure concentrations. Because GBMM is a spatially-distributed model we are able to investigate the importance of such factors (i.e., watershed area, land-use types, and land-use percentages) in transporting and transforming deposited mercury. We present how particular land-use types and land-use change influence total loading and total mercury concentrations, how

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  15. Fish as Biomonitors of Polybrominated Diphenyl Ethers and Hexabromocyclododecane in Czech Aquatic Ecosystems: Pollution of the Elbe River Basin

    PubMed Central

    Pulkrabová, Jana; Hajšlová, Jana; Poustka, Jan; Kazda, Radek

    2007-01-01

    Background Brominated flame retardants (BFRs)—polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD)—belong to the group of relatively “new” environmental contaminants. The occurrence of these compounds in the Czech aquatic ecosystem was for the first time documented within the 3-year monitoring study initiated in 2001. In 2002–2003 HBCD and the major PBDE congeners (28, 47, 49, 66, 85, 99, 100, 153, 154, and 183) were found in 136 freshwater fish samples collected from several sampling sites located at three Czech rivers (Vltava, Elbe, Tichá Orlice). Chub (Leuciscus cephalus), barbel (Barbus barbus), bream (Abramis brama), perch (Perca fluviatilis), and trout (Salmo trutta), representing the most common fish species, were examined by gas chromatography coupled with negative chemical ionization mass spectrometry. Results The presence of PBDE congeners and HBCD was detected in all analyzed samples (limits of detection for target analyts ranged from 0.015 to 0.1 ng/g lipid weight). Without exception the dominating congener was BDE-47. The most pronounced extent of fish contamination was found in the Vltava river at Klecany, downstream from the industrial agglomeration of Prague. As for fish species, the highest concentrations of PBDEs (sum of congeners) were measured in benthic species, represented by bream and barbel, up to 19.6 ng/g wet weight and 16.5 ng/g wet weight, respectively. The lowest accumulation occurred in predator fish (perch and trout). The highest levels of HBCD were detected in barbel from Srnojedy on the Elbe River (15.6 ng/g wet weight), downstream. PMID:18174947

  16. Risk mitigation measures for diffuse pesticide entry into aquatic ecosystems: proposal of a guide to identify appropriate measures on a catchment scale.

    PubMed

    Bereswill, Renja; Streloke, Martin; Schulz, Ralf

    2014-04-01

    Measures to mitigate the risk of pesticide entry into aquatic ecosystems are becoming increasingly more important in the management of hot spots of pesticide transfer; such management, for example, is required by the European Union's directive for the sustainable use of pesticides (2009/128/EC). Measures beyond those currently stipulated for pesticide product authorization may be needed. A concise compilation of the appropriate measures for users (that are primarily farmers but also, e.g., regulators and farm extension services) and a guide for practically identifying these measures at the catchment scale is currently not available. Therefore, a proposal was developed for a guide focusing on the most important diffuse entry pathways (spray drift and runoff). Based on a survey of exposure-relevant landscape parameters (i.e., the riparian buffer strip width, riparian vegetation type, density of ground vegetation cover, coverage of the water body with aquatic macrophytes, field slope, and existence of concentrated flow paths), a set of risk mitigation measures focusing on the specific situation of pollution of a water body catchment can be identified. The user can then choose risk mitigation measures to implement, assisted by evaluations of their efficiency in reducing pesticide entry, feasibility, and expected acceptability to farmers. Currently, 12 landscape-related measures and 6 application-related measures are included. The present guide presents a step toward the practical implementation of risk mitigation measures for reducing pesticide entry in aquatic ecosystems. PMID:24431010

  17. Non-use Economic Values for Little-Known Aquatic Species at Risk: Comparing Choice Experiment Results from Surveys Focused on Species, Guilds, and Ecosystems.

    PubMed

    Rudd, Murray A; Andres, Sheri; Kilfoil, Mary

    2016-09-01

    Accounting for non-market economic values of biological diversity is important to fully assess the benefits of environmental policies and regulations. This study used three choice experiments (species-, guild-, and ecosystem-based surveys) in parallel to quantify non-use values for little-known aquatic species at risk in southern Ontario. Mean willingness-to-pay (WTP) ranged from $9.45 to $21.41 per listing status increment under Canada's Species at Risk Act for both named and unnamed little-known species. Given the broad range of valuable ecosystem services likely to accrue to residents from substantial increases in water quality and the rehabilitation of coastal wetlands, the difference in WTP between species- and ecosystem-based surveys seemed implausibly small. It appeared that naming species-the 'iconization' of species in two of the three surveys-had an important effect on WTP. The results suggest that reasonable annual household-level WTP values for little-known aquatic species may be $10 to $25 per species or $10 to $20 per listing status increment. The results highlighted the utility of using parallel surveys to triangulate on non-use economic values for little-known species at risk. PMID:27294723

  18. Non-use Economic Values for Little-Known Aquatic Species at Risk: Comparing Choice Experiment Results from Surveys Focused on Species, Guilds, and Ecosystems

    NASA Astrophysics Data System (ADS)

    Rudd, Murray A.; Andres, Sheri; Kilfoil, Mary

    2016-09-01

    Accounting for non-market economic values of biological diversity is important to fully assess the benefits of environmental policies and regulations. This study used three choice experiments (species-, guild-, and ecosystem-based surveys) in parallel to quantify non-use values for little-known aquatic species at risk in southern Ontario. Mean willingness-to-pay (WTP) ranged from 9.45 to 21.41 per listing status increment under Canada's Species at Risk Act for both named and unnamed little-known species. Given the broad range of valuable ecosystem services likely to accrue to residents from substantial increases in water quality and the rehabilitation of coastal wetlands, the difference in WTP between species- and ecosystem-based surveys seemed implausibly small. It appeared that naming species—the `iconization' of species in two of the three surveys—had an important effect on WTP. The results suggest that reasonable annual household-level WTP values for little-known aquatic species may be 10 to 25 per species or 10 to 20 per listing status increment. The results highlighted the utility of using parallel surveys to triangulate on non-use economic values for little-known species at risk.

  19. Distribution and transport kinetics of radionuclides sup 99 Mo and sup 131 I in a simulated aquatic ecosystem

    SciTech Connect

    Svadlenkova, M.; Konecny, J.; Obdrzalek, M.; Simanov, L. )

    1990-04-01

    Radioactive liquid wastes from nuclear power stations increase the activity not only of water but also of sediment, aquatic and shore plants, and animals. On average, the majority of the total radioactivity brought to the aquatic system is absorbed by the sediment; the remaining fraction is distributed between water and biomass. For us to be able to assess the influence of the nuclear power station at Temelin in South Bohemia on the nearby hydrosphere, the authors concentrated first on the experimental investigation of the distribution and transport kinetics of some radionuclides in a simulated aquatic system.

  20. Deposition of chromium in aquatic ecosystem from effluents of handloom textile industries in Ranaghat–Fulia region of West Bengal, India

    PubMed Central

    Sanyal, Tanmay; Kaviraj, Anilava; Saha, Subrata

    2014-01-01

    Accumulation of chromium (Cr) was determined in water, sediment, aquatic plants, invertebrates and fish in aquatic ecosystems receiving effluents from handloom textile industries in Ranaghat–Fulia region of West Bengal in India. Cr was determined in the samples by atomic absorption spectrophotometer and data were analyzed functionally by Genetic Algorithm to determine trend of depositions of Cr in the sediment and water. Area plot curve was used to represent accumulation of Cr in biota. The results indicate that the aquatic ecosystems receiving the effluents from handloom textile factories are heavily contaminated by Cr. The contamination is hardly reflected in the concentration of Cr in water, but sediment exhibits seasonal fluctuation in deposition of Cr, concentration reaching to as high as 451.0 μg g−1 during the peak production period. There is a clear trend of gradual increase in the deposition of Cr in the sediment. Aquatic weed, insect and mollusk specimens collected from both closed water bodies (S1 & S2) and riverine resources (S3 & S4) showed high rate of accumulation of Cr. Maximum concentration of Cr was detected in roots of aquatic weeds (877.5 μg g−1). Fish specimens collected from the polluted sites (S3 & S4) of river Churni showed moderate to high concentration of Cr in different tissues. Maximum concentration was detected in the liver of Glossogobius giuris (679.7 μg g−1) during monsoon followed by gill of Mystus bleekeri (190.0 μg g−1) and gut of G. giuris (123.7 μg g−1) during summer. Eutropiichthys vacha showed moderately high concentration of Cr in different tissues (65–99 μg g−1) while Puntius sarana showed relatively low concentration of Cr (below detection limit to 18.0 μg g−1) in different tissues except in gill (64.4 μg g−1). PMID:26644938

  1. Deposition of chromium in aquatic ecosystem from effluents of handloom textile industries in Ranaghat-Fulia region of West Bengal, India.

    PubMed

    Sanyal, Tanmay; Kaviraj, Anilava; Saha, Subrata

    2015-11-01

    Accumulation of chromium (Cr) was determined in water, sediment, aquatic plants, invertebrates and fish in aquatic ecosystems receiving effluents from handloom textile industries in Ranaghat-Fulia region of West Bengal in India. Cr was determined in the samples by atomic absorption spectrophotometer and data were analyzed functionally by Genetic Algorithm to determine trend of depositions of Cr in the sediment and water. Area plot curve was used to represent accumulation of Cr in biota. The results indicate that the aquatic ecosystems receiving the effluents from handloom textile factories are heavily contaminated by Cr. The contamination is hardly reflected in the concentration of Cr in water, but sediment exhibits seasonal fluctuation in deposition of Cr, concentration reaching to as high as 451.0 μg g(-1) during the peak production period. There is a clear trend of gradual increase in the deposition of Cr in the sediment. Aquatic weed, insect and mollusk specimens collected from both closed water bodies (S1 & S2) and riverine resources (S3 & S4) showed high rate of accumulation of Cr. Maximum concentration of Cr was detected in roots of aquatic weeds (877.5 μg g(-1)). Fish specimens collected from the polluted sites (S3 & S4) of river Churni showed moderate to high concentration of Cr in different tissues. Maximum concentration was detected in the liver of Glossogobius giuris (679.7 μg g(-1)) during monsoon followed by gill of Mystus bleekeri (190.0 μg g(-1)) and gut of G. giuris (123.7 μg g(-1)) during summer. Eutropiichthys vacha showed moderately high concentration of Cr in different tissues (65-99 μg g(-1)) while Puntius sarana showed relatively low concentration of Cr (below detection limit to 18.0 μg g(-1)) in different tissues except in gill (64.4 μg g(-1)). PMID:26644938

  2. Modelling Pb, Zn and As transfer from terrestrial to aquatic ecosystems during the ice-free season in three Pyrenean catchments.

    PubMed

    Bacardit, Montserrat; Camarero, Lluís

    2010-11-01

    Long-range atmospheric trace element contamination affecting natural systems has occurred since early historical times in the Northern Hemisphere. In relatively remote sites, soils are the largest reservoir of these airborne contaminants. Trace elements stored in soils can later be remobilized and thus soils are a potential delayed, long-lasting source of contamination for the aquatic ecosystems. Here we measured the atmospheric deposition and in-lake fluxes in order to model the transfer of Pb, Zn and As from terrestrial to aquatic ecosystems during the snow- and ice-free season in three mountain catchments in the Central Pyrenees. According to the model, there was a net export of Pb and As from the catchments. We postulate that accumulated anthropogenic Pb contamination and the weathering of As-rich rocks are the most likely sources. In contrast, Zn was largely retained in the catchment. For Pb and As, the terrestrial inputs were >91% and for Zn were ~71% of the total inputs to the lakes. Nearly all Pb entering the lakes was retained in the sediments whereas 5-38% of As and Zn was lost through the outflow. We were unable to adjust the model for Zn for one of the lakes. The uptake by macrophytes could be a considerable sink for Zn, which was not considered in our transport model. PMID:20869098

  3. Science for Managing Riverine Ecosystems: Actions for the USGS Identified in the Workshop "Analysis of Flow and Habitat for Instream Aquatic Communities"

    USGS Publications Warehouse

    Bencala, Kenneth E.; Hamilton, David B.; Petersen, James H.

    2006-01-01

    Federal and state agencies need improved scientific analysis to support riverine ecosystem management. The ability of the USGS to integrate geologic, hydrologic, chemical, geographic, and biological data into new tools and models provides unparalleled opportunities to translate the best riverine science into useful approaches and usable information to address issues faced by river managers. In addition to this capability to provide integrated science, the USGS has a long history of providing long-term and nationwide information about natural resources. The USGS is now in a position to advance its ability to provide the scientific support for the management of riverine ecosystems. To address this need, the USGS held a listening session in Fort Collins, Colorado in April 2006. Goals of the workshop were to: 1) learn about the key resource issues facing DOI, other Federal, and state resource management agencies; 2) discuss new approaches and information needs for addressing these issues; and 3) outline a strategy for the USGS role in supporting riverine ecosystem management. Workshop discussions focused on key components of a USGS strategy: Communications, Synthesis, and Research. The workshop identified 3 priority actions the USGS can initiate now to advance its capabilities to support integrated science for resource managers in partner government agencies and non-governmental organizations: 1) Synthesize the existing science of riverine ecosystem processes to produce broadly applicable conceptual models, 2) Enhance selected ongoing instream flow projects with complementary interdisciplinary studies, and 3) Design a long-term, watershed-scale research program that will substantively reinvent riverine ecosystem science. In addition, topical discussion groups on hydrology, geomorphology, aquatic habitat and populations, and socio-economic analysis and negotiation identified eleven important complementary actions required to advance the state of the science and to

  4. Experimental and mathematical modeling of the consumer’s influence on productivity of algae in a model aquatic ecosystem

    NASA Astrophysics Data System (ADS)

    Pisman, T. I.; Galayda, Ya. V.; Shirobokova, I. M.

    A "producer-consumer" ( Chlorella vulgaris- Paramecium caudatum) closed aquatic system has been investigated experimentally and theoretically. It has been found that there is a direct relationship between the growth of the paramecia population and their release of ammonia nitrogen, which is the best form of nitrogen for Chlorella growth. The theoretical study of a model of a "producer-consumer" aquatic biotic cycle with spatially separated compartments has confirmed the contribution of paramecia to nitrogen cycling. It has been shown that an increase in the concentration of nitrogen released as metabolites of paramecia is accompanied by an increase in the productivity of microalgae.

  5. The Effects of Mountaintop Mines and Valley Fills on Aquatic Ecosystems of the Central Appalachian Coalfields (External Review Draft)

    EPA Science Inventory

    This report assesses the state of the science on the environmental impacts of mountaintop mines and valley fills (MTM-VF) on streams in the Central Appalachian Coalfields. Our review focused on the aquatic impacts of mountaintop removal coal mining, which, as its name suggests, ...

  6. Optimization of aquatic-terrestrial ecosystem in relation to soil nitrogen status for the cultivation of fish and aquatic food crops of the Indian subtropics.

    PubMed

    Puste, A M; Das, D K

    2001-12-01

    A case study was undertaken during wet and postwet seasons to improve the perennial and alternate submerged saucer-shaped ponded lands (tal and semi-tal lands) in the coasts and northeastern plains of the Indian subtropics through pisciculture and cultivation of starch- and protein-rich aquatic food crops like water chestnut (Trapa bispinosa Roxb.) and makhana or fox nut (Euryale ferox Salisb.). The study revealed that the physico-chemical properties of soils (pH, organic C, organic matter, available N, P, and K) as well as quality of water (pH, EC, BOD, COD, CO3 +, HCO3-, NO3-N, SO4-S-, and Cl-), growing fish, makhana, and water chestnut was remarkably influenced by different moisture regimes and exhibited a significant improvement of soil health. The amount of organic C, available N, P, and K content were found significantly highest in the treatment where makhana was grown under alternate flooding and drying situation with a depth >2 m as compared to other treatments. Such enrichment of soil fertility, particularly in available N and P content, might be due to the accumulation of considerable amounts of biomass and fish excreta and their subsequent decomposition in situ in the soils. Therefore, the present study suggests that the N-enriched soil may effectively be utilized further for growing subsequent arable crops surroundings during summer season, which not only saves the amount of applied N fertilizer but also increases the apparent N efficiency with simultaneous increase in yield, and would benefit the farmers in this region. PMID:12805737

  7. Difference of Ecosystem and Hydrological control on Long-term water quality between adjacent subcatchments in a forested catchment in central Japan

    NASA Astrophysics Data System (ADS)

    Katsuyama, M.; Iwasaki, K.; Nagano, R.; Takaki, K.; Tanaka, Y.

    2014-12-01

    ecosystem. Therefore, it is important to continue the monitoring and to consider the mechanisms. We will discuss about the mechanisms and the differences between adjacent subcatchments considering the water quality of the precipitation and the groundwater as well as the hydrological parameters at the coming meeting.

  8. Evaluating the risk to aquatic ecosystems posed by leachate from tire shred fill in roads using toxicity tests, toxicity identification evaluations, and groundwater modeling.

    PubMed

    Sheehan, Patrick J; Warmerdam, John M; Ogle, Scott; Humphrey, Dana N; Patenaude, Stacey M

    2006-02-01

    The risk to adjacent aquatic systems posed by leachates from scrap tires used in engineering applications has not been characterized adequately. Toxicity testing, toxicity identification evaluation (TIE), and groundwater modeling were used to determine the circumstances under which tire shreds could be used as roadbed fill with negligible risk to aquatic organisms in adjacent water bodies. Elevated levels of iron, manganese, and several other chemicals were found in tire shred leachates. However, chronic toxicity tests with Ceriodaphnia dubia and fathead minnows (Pimephales promelas) showed no adverse effects caused by leachates collected from tire shreds installed above the water table. Exposure to leachates collected from tire shreds installed below the water table resulted in significant reductions to both survival and reproduction in C. dubia. The TIE results indicated that exposure to soluble metals (likely ferrous iron primarily) and the formation of iron hydroxide precipitates on this invertebrate species likely were the causes of the observed effects. The available chemistry data show that iron concentrations in the affected groundwater decreased substantially within a short distance (0.61 m) downgradient of tire shred fill. Based on geochemical modeling, the use of tire shreds in applications below the water table is appropriate in settings where dissolved oxygen is greater than 2.0 mg/L, pH is greater than 5.8, and a downgradient buffer of approximately 3.0 m exists between the fill and the surface water. For settings with lower dissolved oxygen concentrations or lower pH, results of groundwater modeling indicate that a greater buffer distance (approximately 11 m) is needed to dilute the leachate to nontoxic levels under various soil and groundwater conditions solely through advection and dispersion processes. PMID:16519300

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

    PubMed

    Rozema, J; Björn, L O; Bornman, J F; Gaberscik, A; Häder, D-P; Trost, T; Germ, M; Klisch, M; Gröniger, A; Sinha, R P; Lebert, M; He, Y-Y; Buffoni-Hall, R; de Bakker, N V J; van de Staaij, J; Meijkamp, B B

    2002-02-01

    We analysed and compared the functioning of UV-B screening pigments in plants from marine, fresh water and terrestrial ecosystems, along the evolutionary line of cyanobacteria, unicellular algae, primitive multicellular algae, charophycean algae, lichens, mosses and higher plants, including amphibious macrophytes. Lichens were also included in the study. We were interested in the following key aspects: (a) does the water column function effectively as an 'external UV-B filter'?; (b) do aquatic plants need less 'internal UV-B screening' than terrestrial plants?; (c) what role does UV screening play in protecting the various plant groups from UV-B damage, such as the formation of thymine dimers?; and (d) since early land 'plants' (such as the predecessors of present-day cyanobacteria, lichens and mosses) experienced higher UV-B fluxes than higher plants, which evolved later, are primitive aquatic and land organisms (cyanobacteria, algae, lichens, mosses) better adapted to present-day levels of UV-B than higher plants? Furthermore, polychromatic action spectra for the induction of UV screening pigments of aquatic organisms have been determined. This is relevant for translating 'physical' radiation measurements of solar UV-B into 'biological' and 'ecological' effects. From the action spectra, radiation amplification factors (RAFs) have been calculated. These action spectra allow us to determine any mitigating or antagonistic effects in the ecosystems and therefore qualify the damage prediction for the ecosystems under study. We summarize and discuss the main results based on three years of research of four European research groups. The central theme of the work was the investigation of the effectiveness of the various screening compounds from the different species studied in order to gain some perspective of the evolutionary adaptations from lower to higher plant forms. The induction of mycosporine-like amino acids (MAAs) was studied in the marine dinoflagellate

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

    ERIC Educational Resources Information Center

    Hatheway, W. H.

    These materials were designed to be used by life science students for instruction in the application of physical theory to ecosystem operation. Most modules contain computer programs which are built around a particular application of a physical process. Specifically, this module develops a method for calculating the exchange of heat between an…

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

    ERIC Educational Resources Information Center

    Gales, Larry

    These materials were designed to be used by life science students for instruction in the application of physical theory to ecosystem operation. Most modules contain computer programs which are built around a particular application of a physical process. PRNT3D is a subroutine package which generates a variety of printed plot displays. The displays…

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

    ERIC Educational Resources Information Center

    Gales, Larry

    This module is part of a series designed to be used by life science students for instruction in the application of physical theory to ecosystem operation. Most modules contain computer programs which are built around a particular application of a physical process. PLOT3D is a subroutine package which generates a variety of three dimensional hidden…

  13. Design Standards for Instructional Computer Programs. Physical Processes in Terrestrial and Aquatic Ecosystems, Computer Programs and Graphics Capabilities.

    ERIC Educational Resources Information Center

    Gales, Larry

    These materials were designed to be used by life science students for instruction in the application of physical theory to ecosystem operation. Most modules contain computer programs which are built around a particular application of a physical process. The report describes design standards for the computer programs. They are designed to be…

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

    ERIC Educational Resources Information Center

    Gales, Larry; Anderson, Lougenia

    These materials were designed to be used by life science students for instruction in the application of physical theory to ecosystem operation. Most modules contain computer programs which are built around a particular application of a physical process. FFORM is a portable format-free input subroutine package which simplifies the input of values…

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

    ERIC Educational Resources Information Center

    Gales, Larry

    This module is part of a series designed to be used by life science students for instruction in the application of physical theory to ecosystem operation. Most modules contain computer programs which are built around a particular application of a physical process. PLOT3D is a subroutine package which generates a variety of three-dimensional hidden…

  16. Dimensional Methods: Dimensions, Units and the Principle of Dimensional Homogeneity. Physical Processes in Terrestrial and Aquatic Ecosystems, Applied Mathematics.

    ERIC Educational Resources Information Center

    Fletcher, R. Ian

    These materials were designed to be used by life science students for instruction in the application of physical theory to ecosystem operation. Most modules contain computer programs which are built around a particular application of a physical process. The module is concerned with conventional techniques such as concepts of measurement,…

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

    ERIC Educational Resources Information Center

    Stevenson, R. D.

    This module is part of a series designed to be used by life science students for instruction in the application of physical theory to ecosystem operation. Most modules contain computer programs which are built around a particular application of a physical process. This module describes heat transfer processes involved in the exchange of heat…

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

    ERIC Educational Resources Information Center

    Gales, Larry

    These materials were designed to be used by life science students for instruction in the application of physical theory to ecosystem operation. Most modules contain computer programs which are built around a particular application of a physical process. PRNT3D is a subroutine package which generates a variety of printer plot displays. The displays…

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

    ERIC Educational Resources Information Center

    Stevenson, R. D.

    These materials were designed to be used by life science students for instruction in the application of physical theory to ecosystem operation. Most modules contain computer programs which are built around a particular application of a physical process. Thermoregulation is defined as the ability of an organism to modify its body temperature. This…

  20. Application of Bayesian belief net in modelling the origin and effects of terrigenous dissolved organic matter in a boreal aquatic ecosystem

    NASA Astrophysics Data System (ADS)

    Rahikainen, Mika; Hoikkala, Laura; Soinne, Helena

    2013-04-01

    Bayesian belief nets (BBN) are capable of developing holistic understanding of the origin, transportation, and effects of dissolved organic matter (DOM) in ecosystems. The role of riverine DOM, transporting carbon and macronutrients N and P into lakes and coastal areas, has been largely neglected in research about processes influencing aquatic ecosystem functions although dissolved organic matter provides a significant nutrient source for primary producers in aquatic environments. This neglect has also contributed to the environmental policies which are focused in the control of inorganic N and P load. It is of great social and economic interest to gain improved knowledge of whether the currently applied policy instruments act in synchrony in mitigating eutrophication caused by N and P versus DOM load. DOM is a complex mixture of compounds that are poorly characterized. DOM export is strongly regulated by land use (urban, forest, agricultural land, peat land), in addition to soil type and soil organic carbon concentration. Furthermore, the composition of DOM varies according to its origin. The fate and effects of DOM loads in the fresh water and coastal environments depend, for example, on their biodegradability. Degradation kinetics again depends on the interactions between composition of the DOM pool and the receiving environment. Impact studies of dissolved organic matter pose a complicated environmental impact assessment challenge for science. There exists strategic uncertainty in the science about the causal dependencies and about the quality of knowledge related to DOM. There is a clear need for systematization in the approach as uncertainty is typically high about many key processes. A cross-sectorial, integrative analysis will aid in focusing on the most relevant issues. A holistic and unambiguous analysis will provide support for policy-decisions and management by indicating which outcome is more probable than another. The task requires coupling complex

  1. Experimental and mathematical modelling of the consumer influence on the productivity of algae in a model aquatic ecosystem

    NASA Astrophysics Data System (ADS)

    Pisman, T. I.; Galayda, Y. V.; Shirobokova, I. M.

    Based upon the experimental and theoretical results the possibility of increasing the microalgal productivity in the "producer - consumer" aquatic biotic cycle (Chlorella vulgaris - Paramecium caudatum) has been considered. The experiment was held on the device with spatially divided links, which consists of a fermenter for Chlorella cultivation (the "producer" link) and a fermenter for Paramecia growing (the "consumer" link). The direct relation between the reproduction of Paramecia at consuming Chlorella and emission of nitrogen in ammonium form, which is the most preferable for growing Chlorella, has been revealed. In the result of theoretical study of the model of the "producer - consumer" aquatic biotic cycle with spatially divided links the contribution of Paramecia to the nitrogen cycle has been proved. It was shown that simultaneously with the increase of concentration of nitrogen evolved in the process of Paramecia metabolism, the biomass of Chlorella increases as well. The possibility of increasing the productivity of agal growth in the presence of a predator in a different way (due to decrease of limitation on light) has been considered. A laboratory growth experiment revealed a positive effect of Gammarus presence on Ulva spp. growth, probably caused by removal of epiphytic diatoms from the Ulva spp. thalli.

  2. Assessment in situ of genotoxicity in tadpoles and adults of frog Hypsiboas cordobae (Barrio 1965) inhabiting aquatic ecosystems associated to fluorite mine.

    PubMed

    Pollo, Favio E; Grenat, Pablo R; Otero, Manuel A; Salas, Nancy E; Martino, Adolfo L

    2016-11-01

    Non-lethal biological techniques such as blood biomarkers have gained attention due to their value as early signals of anthropic effects of contamination representing significant tools to evaluate ecosystems health. We evaluate and characterize in situ genotoxicity of water samples collected from aquatic ecosystems around a fluorite mine using amphibian frogs Hypsiboas cordobae as bioindicator species complemented with 16 physicochemical parameters. Four stations associated with fluorite mine sampling were sampled: a stream running on granitic rock with natural high fluorite content; two streams both running on metamorphic rock with low fluorite content; and an artificial decantation pond containing sediments produced by fluorite flotation process with high variation in physicochemical parameters. We analyses the blood of tadpoles and adults of H. Cordobae, calculated frequencies of micronuclei, erythrocyte nuclear abnormalities, mitosis, immature and enucleated erythrocytes. Individuals were measured and weighed and body condition was calculated. The results of this study indicate that individuals of decantation pond are exposed to compounds or mixtures which are causing cell damage when compared to those that were collected of stream. Larval stage was more vulnerable than the adult phase and it could be related mainly to the higher exposure time to xenobiotics, which can penetrate easily by skin, mouth and gills; additionally this site offers a reduced availability of food than other sites. Therefore, chronic exposure to pollutants could derive in degenerative and neoplastic diseases in target organs. Moreover these individuals may experience reproductive and behavioral disturbances which could lead to population decline in the long term. PMID:27522316

  3. The McMurdo Dry Valleys, Antarctica: Terrestrial and aquatic ecosystems responding to climatic events that enhance hydrologic transport across the landscape (John Dalton Medal Lecture)

    NASA Astrophysics Data System (ADS)

    McKnight, Diane

    2015-04-01

    While continuous monitoring of stream flow and stream temperature has been a widely used resource for some time, currently there is great potential to expand continuous monitoring to include important water quality parameters such as nutrients and dissolved organic material. In many systems distinguishing between watershed and stream ecosystem controls can be challenging, and the usefulness of such monitoring can be enhanced by application of quantitative models to interpret observed patterns. The glacial meltwater streams of the McMurdo Dry Valleys, Antarctica, are surrounded by large expanses of patterned ground devoid of plants. In contrast, many streams have thriving cyanobacterial mats that are freeze-dried through the winter and begin photosynthesis with the onset of flow. Thus, the daily signal in terms of biogeochemical processes controlling water quality is generated within the stream. As part of the McMurdo Dry Valleys Long Term Ecological Research project, we have conducted field experiments and developed coupled biogeochemical transport models for the role of hyporheic exchange in controlling weathering of major ions, microbial cycling of nitrogen species, and streams temperature regulation. We have also adapted modelling approaches from sediment transport to understand mobilization of stream biomass with increasing flows. These models are relevant to understanding the role of in-stream processes in diverse stream systems where watershed processes also contribute to observed patterns. In the future, monitored data may be directly incorporated into such process models to better understand rapid hydrologic change and their impact on water quality and aquatic ecosystems.

  4. Adaptations of Phytoplankton to Sunlight and Other Optical Properties of Aquatic Ecosystem Particles Detected With a Portable Integrating Sphere Version of QFT

    NASA Astrophysics Data System (ADS)

    Hargreaves, B. R.

    2006-12-01

    Suspended particles in aquatic ecosystems include autotrophic and heterotrophic micro-organisms, organic detritus, and suspended mineral particles. Spectral optical properties of these particles can be useful in characterizing the attenuation of sunlight underwater, the distribution and types of organisms, and their biological response to the underwater physical gradients, including photosynthesis and the release of dissolved organic matter. Recent measurements of spectral absorption of phytoplankton exposed to strong ultraviolet radiation (UVR) near the surface and declining irradiance with depth have shown a tendency to produce natural UV-B sunscreen compounds (MAA's) in proportion to the intensity of exposure to UV-B. A down-regulation of chlorophyll-a pigment with increasing intensity of visible wavelengths is well known. Some recent data also suggest a negative correlation between phytoplankton biomass and water column exposure to UV-B as mediated by stratospheric ozone. The standard method of characterizing the spectral optical properties of particles in aquatic ecosystems is the Quantitative Filterpad Technique (QFT) in which a water sample is concentrated on a fine glass fiber filter (GFF) and its optical density is then measured in the beam of a scanning spectrophotometer. An improved QFT method (QFT-TR) established in the past decade involves laboratory measurement of both transmittance and reflectance for each sample using an integrating sphere attachment in a scanning spectrophotometer. Both methods have disadvantages. Particle spectral data from a number of freshwater ecosystems were collected using a new battery-powered instrument that combines integrating sphere, lamp, and fiber optic spectrometer to create a portable improved QFT (pQFT-TR). Transmittance, reflectances, and absorbance spectra for particles from streams (rich in mineral particles) and lakes (some with humic particles, others with predominantly phytoplankton) are compared using the old

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

    PubMed

    Kim, Heung-Tae; Kim, Jae Geun

    2016-08-01

    The objective of this study was to investigate trace-metal [cadmium (Cd), copper (Cu), lead (Pb), zinc (Zn)] biotransference and biomagnification in terrestrial biota at different trophic levels (primary producer-top predator) of a wetland ecosystem. We investigated whether metal concentrations in the sediment are reflected in terrestrial arthropods and aquatic plants. We sampled the floating-leaved plant Trapa japonica; its species-specific primary consumer, the leaf beetle Galerucella nipponensis; and two predatory arthropods (the water strider Gerris sp. and the wolf spider Arctosa sp.) from three wetlands with different sedimentary metal concentrations. The δ(13)C and δ(15)N signatures in the trophic link between the plants and the leaf beetles supported the specificity of their feeding relationship. The stable isotope signatures indicate that the leaf beetle could be an important link in the trophic transfer of the metals. Transference factors (TFs) were <1 for Pb in all trophic links, and concentrations in the organisms were negatively correlated with the trophic levels. There was no evidence of Pb biomagnification in the food chain. Cu and Zn had TF >1 for all biota, and the concentrations were positively correlated with the trophic levels. Thus, there may be Cu and Zn biomagnification in the arthropods. We noted TF <1 for Cd between the plants and the leaf beetles, but TF was >1 among the arthropods. Therefore, Cd is probably not biomagnified between T. japonica and G. nipponensis, but it might be biomagnified in the arthropods. The metal burden in terrestrial arthropods may also be influenced by uptake from the sediment by aquatic plants. PMID:27306449

  6. Comparison of the sensitivity of electrophoresis and ecological indices for the detection of environmental stress in aquatic ecosystems

    SciTech Connect

    Facemire, C.F.

    1989-01-01

    Selected enzyme systems from a number of aquatic vertebrate and invertebrate species found in three southwestern Ohio Streams were analyzed using electrophoretic techniques. Results were compared with those obtained using various community parameters to determine which method (1) was most sensitive to Pollutant stress, (2) provided the most consistent results when applied to the communities and populations found in the three streams, (3) had the best capability for providing a continuous assessment given a wide range of pollutant stress, (4) was least dependent upon sample size, (5) was most easily calculated, (6) was most able to differentiate between pollutant induced changes and those due to natural cyclic or stochastic ones, and, (7) was most ecologically relevant. Species richness, S, four species diversity indices, the Index of Biotic Integrity, and three community similarity indices were compared to one another and to various genetic measures including allele and genotype frequency data, percent heterozygosity, and Rogers' genetic similarity. In most cases, data from the ecological indices (1) were not correlated with water quality, (2) provided differing interpretations dependent upon the taxa used in the analyses, (3) were unable to discriminate between instream communities, and (4) were often influenced by factors unrelated to contaminant stress including sample size, habitat heterogeneity, season, the life cycle of a dominant species, and the taxonomic group evaluated. Electrophoretic analysis exhibited greater sensitivity to changes in water quality and, in most cases, a high degree of inter-population discriminatory ability.

  7. Correlation of melanophore index with a battery of functional genomic stress indicators for measurement of environmental stress in aquatic ecosystem.

    PubMed

    Daiwile, Atul P; Naoghare, Pravin K; Giripunje, Manisha D; Rao, P D Prasada; Ghosh, Tarun K; Krishnamurthi, Kannan; Alimba, Chibuisi G; Sivanesan, Saravanadevi

    2015-03-01

    The correlation of primary stress indicator; melanophore index (MI) with set of genomic stress indicators is important for a better understanding of the cellular stress pathway induced by xenobiotics in aquatic species. This study presents a correlation between melanophore index (MI) and genomic stress indicators in Oreochromis mossambicus treated with lead nitrate, phenol and hexachlorocyclohexane (HCH). O. mossambicus was exposed to sub-lethal concentrations of the different LC50 values (96 h) of the tested chemicals at varying exposure periods and the response via genomic stress indicators and scale melanophores were assessed in accordance with standard protocols. Melanophore index decreased significantly (p<0.01) in a time dependent pattern to the tested chemicals. Gene expression showed significant time dependent increase in the expression of heat shock proteins (HSP70 and HSP60). Vitellogenin (Vtg) expression insignificantly altered. Significant increase in the expression of melanin concentrating hormone (MCH) was observed in response to hexachlorocyclohexane (HCH) in the treated fish. The findings demonstrated an inverse relationship between melanophore index and the set of genomic stress indicators. PMID:25680093

  8. Community structure of fishes inhabiting aquatic refuges in a threatened Karst wetland and its implications for ecosystem management

    USGS Publications Warehouse

    Kobza, Robert M.; Trexler, J.C.; Loftus, W.F.; Perry, S.A.

    2004-01-01

    We illustrate the importance of subsurface refuges for conservation of aquatic fauna with our studies of karstic wetlands in Everglades National Park, Florida, USA. Managers have proposed that water levels there should not fall more than 46 cm below ground level for more than 90 days annually. In four areas, 84% of solution holes were less than 46 cm deep and holes deeper than lm were rare (<3 km-2). Null-model analysis indicated no "structure" in the solution-hole fish communities early in the dry season, but that structure emerged as drying progressed. Native cyprinodontiforms were abundant in shallow solution holes that dry annually under current management, while predatory species (often non-native) tended to dominate deeper holes. Water quality was correlated with hole volume and with composition of late dry-season fish communities. Tremendous losses of fish biomass occurred when water levels fell below 46 cm from ground surface. Most native taxa were unlikely to survive in the deep refuges that held predatory non-native taxa. ?? 2003 Elsevier Ltd. All rights reserved.

  9. The McMurdo Dry Valleys, Antarctica: Terrestrial and aquatic ecosystems responding to climatic events that enhance hydrologic transport acress the landscape

    NASA Astrophysics Data System (ADS)

    McKnight, D. M.; Lyons, W. B.; Fountain, A. G.; Gooseff, M. N.; Doran, P. T.; Wall, D. H.; Virginia, R. A.; Priscu, J. C.; Adams, B.; Vesbach-Takacs, C.; Barrett, J. E.; Howkins, A.

    2014-12-01

    The McMurdo Dry Valleys of Antarctica is comprised of alpine and terminal glaciers, large expanses of patterned ground, and permanently ice-covered lakes in the valley floors, which are linked by glacial meltwater streams that flow during the austral summer. These valleys were first explored by Robert Scott and his party in 1903. In 1968 the New Zealand Antarctic Program began a gauging network on the Onyx River, a 32 km river in Wright Valley which is the longest river in Antarctica. As part of the McMurdo Dry Valleys Long-Term Ecological research project our research group has monitored meteorological conditions, glacial mass balance, lake level and streamflow in the adjacent Taylor Valley. The extent of liquid water throughout the landscape is strongly controlled by summer climate, and the availability of liquid water in turn is a limitation to the microscopic life that is present in the diverse habitats in the valleys. We have studied the responses of soil, lake, stream and cryoconite ecosystems through a sustained cooling period that has been driven by atmospheric changes associated with the ozone hole. In the past decade, this cooling period appears to have ceased and summer conditions have become more variable. Three warm sunny summers have occurred since 2001/02. These conditions have created weeks long "flood events" in the valleys, causing wet areas to emerge in the soils, thermokarsting in some stream channels and increases in lake level. These flood events can be considered as pulse events that drive an increase in ecosystem connectivity, changing rates of biogeochemical processes and the distribution of biota. Collectively the ecosystems of the McMurdo Dry Valleys are highly responsive to dynamic climatic influences associated with the ozone hole and global warming.

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

    USGS Publications Warehouse

    Larsen, Laurel G.; Harvey, Judson W.

    2011-01-01

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

  11. Biochemical responses of filamentous algae in different aquatic ecosystems in South East Turkey and associated water quality parameters.

    PubMed

    Çelekli, Abuzer; Arslanargun, Hamdullah; Soysal, Çiğdem; Gültekin, Emine; Bozkurt, Hüseyin

    2016-11-01

    To the best of our knowledge, any study about biochemical response of filamentous algae in the complex freshwater ecosystems has not been found in the literature. This study was designed to explore biochemical response of filamentous algae in different water bodies from May 2013 to October 2014, using multivariate approach in the South East of Turkey. Environmental variables were measured in situ: water temperature, oxygen concentration, saturation, conductivity, salinity, pH, redox potential, and total dissolved solid. Chemical variables of aqueous samples and biochemical compounds of filamentous algae were also measured. It was found that geographic position and anthropogenic activities had strong effect on physico-chemical variables of water bodies. Variation in environmental conditions caused change in algal biomass composition due to the different response of filamentous species, also indicated by FTIR analysis. Biochemical responses not only changed from species to species, but also varied for the same species at different sampling time and sampling stations. Multivariate analyses showed that heavy metals, nutrients, and water hardness were found as the important variables governing the temporal and spatial succession and biochemical compounds. Nutrients, especially nitrate, could stimulate pigment and total protein production, whereas high metal content had adverse effects. Amount of malondialdehyde (MDA), H2O2, total thiol groups, total phenolic compounds, proline, total carbohydrate, and metal bioaccumulation by filamentous algae could be closely related with heavy metals in the ecosystems. Significant increase in MDA, H2O2, total thiol group, total phenolic compounds, and proline productions by filamentous algae and chlorosis phenomenon seemed to be an important strategy for alleviating environmental factors-induced oxidative stress as biomarkers. PMID:27508982

  12. The "C.E.B.A.S. MINI-MODULE": a self-sustaining closed aquatic ecosystem for spaceflight experimentation.

    PubMed

    Blum, V; Andriske, M; Ludwig, Ch; Paassen, U; Voeste, D

    2003-01-01

    The C.E.B.A.S. MINI-MODULE is the miniaturized space flight version of the Closed Equilibrated Biological Aquatic System (C.E.B.A.S.). It fits into a large middeck locker tray and is scheduled to be flown in the STS 85 and in the NEUROLAB missions. Its volume is about 9 liters and it consists of two animal tanks, a plant cultivator, and a bacteria filter in a monolithic design. An external sensor unit is connected to a data acquisition/control unit. The system integrates its own biological life support. The CO2 exhaled by the consumers (fishes, snails, microorganisms) is assimilated by water plants (Ceratophyllum demersum) which provide them with oxygen. The products of biomass degradation and excretion (mainly ammonia ions) are converted by bacteria into nitrite and nitrate. The latter is taken up by the plants as a nitrogen source together with other ions like phosphate. The plants convert light energy into chemical energy and their illumination is regulated via the oxygen concentration in the water by the control unit. In ground laboratory tests the system exhibited biological stability up to three month. The buffer capacity of the biological filter system is high enough to eliminate the degradation products of about one half of the dead animal biomass as shown in a "crash test". A test series using the laboratory model of the flight hardware demonstrated the biological stability and technical reliability with mission-identical loading and test duration. A comprehensive biological research program is established for the C.E.B.A.S. MINI-MODULE in which five German and three U.S.-American universities as well as the Russian Academy of Sciences are involved. PMID:12580172

  13. Predicting organic floc transport dynamics in shallow aquatic ecosystems: insights from the field, laboratory, and numerical modeling.

    USGS Publications Warehouse

    Harvey, Judson W.; Noe, Gregory B.; Larsen, Laurel G.; Crimaldi, John P.

    2009-01-01

    Transport of particulate organic material can impact watershed sediment and nutrient budgets and can alter the geomorphologic evolution of shallow aquatic environments. Prediction of organic aggregate (“floc”) transport in these environments requires knowledge of how hydraulics and biota affect the entrainment, settling, and aggregation of particles. This study evaluated the aggregation and field transport dynamics of organic floc from a low-gradient floodplain wetland with flow-parallel ridges and sloughs in the Florida Everglades. Floc dynamics were evaluated in a rotating annular flume and in situ in the field. Under present managed conditions in the Everglades, floc is not entrained by mean flows but is suspended via biological production in the water column and bioturbation. Aggregation was a significant process affecting Everglades floc at high flume flow velocities (7.0 cm s-1) and during recovery from high flow; disaggregation was not significant for the tested flows. During moderate flows when floc dynamics are hydrodynamically controlled, it is possible to model floc transport using a single “operative floc diameter” that accurately predicts fluxes downstream and to the bed. In contrast, during high flows and recovery from high flows, aggregation dynamics should be simulated. When entrained by flow in open-water sloughs, Everglades floc will be transported downstream in multiple deposition and reentrainment events but will undergo net settling when transported onto ridges of emergent vegetation. We hypothesize that net transport of material from open to vegetated areas during high flows is critical for forming and maintaining distinctive topographic patterning in the Everglades and other low-gradient floodplains.

  14. Predicting organic floc transport dynamics in shallow aquatic ecosystems: Insights from the field, the laboratory, and numerical modeling

    USGS Publications Warehouse

    Larsen, L.G.; Harvey, J.W.; Noe, G.B.; Crimaldi, J.P.

    2009-01-01

    Transport of particulate organic material can impact watershed sediment and nutrient budgets and can alter the geomorphologic evolution of shallow aquatic environments. Prediction of organic aggregate ("floc") transport in these environments requires knowledge of how hydraulics and biota affect the entrainment, settling, and aggregation of particles. This study evaluated the aggregation and field transport dynamics of organic floc from a low-gradient floodplain wetland with flow-parallel ridges and sloughs in the Florida Everglades. floc dynamics were evaluated in a rotating annular flume and in situ in the field. Under present managed conditions in the Everglades, floc is not entrained by mean flows but is suspended via biological production in the water column and bioturbation. Aggregation was a significant process affecting Everglades floc at high flume flow velocities (7.0 cm s-1) and during recovery from high flow; disaggregation was not significant for the tested flows. During moderate flows when floc dynamics are hydrodynamically controlled, it is possible to model floc transport using a single "operative floc diameter" that accurately predicts fluxes downstream and to the bed. In contrast, during high flows and recovery from high flows, aggregation dynamics should be simulated. When entrained by flow in open-water sloughs, Everglades floc will be transported downstream in multiple deposition and reentrainment events but will undergo net settling when transported onto ridges of emergent vegetation. We hypothesize that net transport of material from open to vegetated areas during high flows is critical for forming and maintaining distinctive topographic patterning in the Everglades and other low-gradient floodplains. Copyright 2009 by the American Geophysical Union.

  15. The ``C.E.B.A.S. MINI-MODULE'': A self-sustaining closed aquatic ecosystem for spaceflight experimentation

    NASA Astrophysics Data System (ADS)

    Blüm, V.; Andriske, M.; Ludwig, Ch.; Paaßen, U.; Voeste, D.

    The C.E.B.A.S. MINI-MODULE is the miniaturized space flight version of the Closed Equilibrated Biological Aquatic System (C.E.B.A.S.). It fits into a large middeck locker tray and is scheduled to be flown in the STS 85 and in the NEUROLAB missions. Its volume is about 9 liters and it consists of two animal tanks, a plant cultivator, and a bacteria filter in a monolithic design. An external sensor unit is connected to a data acquisition/control unit. The system integrates its own biological life support. The CO2 exhaled by the consumers (fishes, snails, microorganisms) is assimilated by water plants (Ceratophyllum demersum) which provide them with oxygen. The products of biomass degradation and excretion (mainly ammonia ions) are converted by bacteria into nitrite and nitrate. The latter is taken up by the plants as a nitrogen source together with other ions like phosphate. The plants convert light energy into chemical energy and their illumination is regulated via the oxygen concentration in the water by the control unit. In ground laboratory tests the system exhibited biological stability up to three month. The buffer capacity of the biological filter system is high enough to eliminate the degradation products of about one half of the dead animal biomass as shown in a ``crash test''. A test series using the laboratory model of the flight hardware demonstrated the biological stability and technical reliability with mission-identical loading and test duration. A comprehensive biological research program is established for the C.E.B.A.S. MINI-MODULE in which five German and three U.S.-American universities as well as the Russian Academy of Sciences are involved.

  16. Calcium Carbonate Phosphate Binding Ion Exchange Filtration and Accelerated Denitrification Improve Public Health Standards and Combat Eutrophication in Aquatic Ecosystems

    PubMed Central

    Yanamadala, Vijay

    2010-01-01

    Cultural eutrophication, the process by which a lake becomes rich in dissolved nutrients as a result of point and nonpoint pollutant sources, is a major cause of the loss of natural lake ecosystems throughout the world. The process occurs naturally in all lakes, but phosphate-rich nutrient runoff from sources such as storm drains and agricultural runoff is a major cause of excess phosphate-induced eutrophication. Especially in Madrona Marsh, one of the last remaining vernal marshes in the greater Los Angeles area, California, cultural eutrophication has become a major problem. In this study, calcium carbonate was found to be an excellent phosphate binder, reducing up to 70% of the phosphates in a given sample of water, and it posed relatively negligent ecological repercussions. This study involved the testing of this principle in both the laboratory and the real ecosystem. A calcium carbonate lacing procedure was first carried out to determine its efficacy in Madrona Marsh. Through this, ammonia was found to interfere with the solubility of calcium carbonate and therefore to be a hindrance to the reduction of phosphate. Therefore, various approaches for reduction of ammonia were tested, including aeration, use of fiber growth media, and plants, mainly Caulerpa verticellata, chosen for it hardiness, primarily in an attempt to increase population of Nitrobacter and Nitrosomonas. All were successful in moderately reducing ammonia levels. In addition, soil sampling, sediment analysis, microscopic plant analysis, microorganism and macroinvertebrate identification, and rate law formulations were conducted. The effect of phosphate and ammonia reduction on the populations of enterobacteria was also an important focus of this experiment. Varying concentrations of phosphate, ammonia, and calcium carbonate in conjunction with phosphate were tested in Madrona Marsh to determine their effects on the populations of enteropathogens on nonspecific blood agar, MacConkey agar, and

  17. Distribution of trace elements in the aquatic ecosystem of the Thigithe river and the fish Labeo victorianus in Tanzania and possible risks for human consumption.

    PubMed

    Mataba, Gordian Rocky; Verhaert, Vera; Blust, Ronny; Bervoets, Lieven

    2016-03-15

    The aim of the present study was to assess the distribution of trace elements in the aquatic ecosystem of the Thigithe river. Samples of surface water, sediment and fish were collected up- and downstream of the North Mara Gold Mine (Tanzania) and following trace elements were analysed: As, Cd, Co, Cr, Cu, Hg, Ni, Pb and Zn. Trace element concentrations in surface water were below or near the detection limit. Regarding the sediments, relative high concentrations of arsenic at all sites and high levels of mercury at a site downstream of the mine where artisanal mining is performed were observed. Trace element concentrations in Ningu fish tissues (Labeo victorianus) were comparable to slightly higher than levels in fishes from unpolluted environments. For none of the measured human health risk by consumption of fish from the Thigithe river is expected when the Tanzanian average amount of 17 g/day is consumed. However, for Hg and As the advised maximum daily consumption of Ningu fish was lower than 100g. As a result fishermen and people living along the shores of the river consuming more fish than the average Tanzanian fish consumption set by the FAO (2005) are possibly at risk. PMID:26780131

  18. Climate and hydrological changes in the northeastern United States: recent trends and implications for forested and aquatic ecosystems

    USGS Publications Warehouse

    Huntington, Thomas G.; Richardson, Andrew D.; McGuire, Kevin J.; Hayhoe, Katharine

    2009-01-01

    We review twentieth century and projected twenty-first century changes in climatic and hydrologic conditions in the northeastern United States and the implications of these changes for forest ecosystems. Climate warming and increases in precipitation and associated changes in snow and hydrologic regimes have been observed over the last century, with the most pronounced changes occurring since 1970. Trends in specific climatic and hydrologic variables differ in their responses spatially (e.g., coastal vs. inland) and temporally (e.g., spring vs. summer). Trends can differ depending on the period of record analyzed, hinting at the role of decadal-scale climatic variation that is superimposed over the longer-term trend. Model predictions indicate that continued increases in temperature and precipitation across the northeastern United States can be expected over the next century. Ongoing increases in growing season length (earlier spring and later autumn) will most likely increase evapotranspiration and frequency of drought. In turn, an increase in the frequency of drought will likely increase the risk of fire and negatively impact forest productivity, maple syrup production, and the intensity of autumn foliage coloration. Climate and hydrologic changes could have profound effects on forest structure, composition, and ecological functioning in response to the changes discussed here and as described in related articles in this issue of the Journal.

  19. Lotic aquatic ecosystems of the Savannah River Plant: Impact evaluation, habitat analyses and the lower food chain communities: Volume 1

    SciTech Connect

    Firth, P.; O'Hop, J.R.; Coler, B.; Green, R.A.

    1986-04-01

    This report documents a study of animal habitat and the lower food chain communities in the streams and swamps of the Savannah River Plant (SRP). The purpose of the study was to assess the impacts of SRP operations on the lotic (flowing water) ecosystems on the plant site and on portions of the Savannah River. The 1985 survey year included the period between 1 October 1984 and 30 September 1985. Forty-seven stations located on five drainage basins within the SRP boundaries and on the Savannah River were sampled. The drainage basins were: Upper Three Runs Creek (3 sites), Beaver Dam Creek-Four Mile Creek (5 and 7 sites, respectively), Pen Branch (5 sites), Steel Creek-Meyers Branch system (12 and 2 sites, respectively), and Lower Three Runs Creek (5 sites). The remaining eight sites were on the Savannah River, upstream and downstream of creek mouths. Fifteen of the sites were thermal due to heated effluents from D-area power plant (discharging to Beaver Dam Creek), C-reactor (discharging to Four Mile Creek), or K-reactor (discharging to Pen Branch). 224 refs., 20 figs., 131 tabs.

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

    PubMed Central

    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

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

    NASA Astrophysics Data System (ADS)

    Larsen, Laurel G.; Harvey, Judson W.

    2011-03-01

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

  2. The Aquatic Systems Continuum

    NASA Astrophysics Data System (ADS)

    Winter, T. C.

    2004-12-01

    The Aquatic Systems Continuum is a proposed framework for interrelating the physical, chemical, and biological characteristics of aquatic ecosystems. The continuum can be represented by a three-dimensional matrix that relates aquatic ecosystems to their position within hydrologic flow paths (x-axis, a spatial dimension) and their response to climate variability (y-axis). The z-axis describes the structure of biological communities as they relate to the hydrological conditions defined by the x and y axes. The concept is an extension of the Wetland Continuum that was derived from field studies of a prairie pothole wetland complex in North Dakota. At that site, the hydrologic continuum in space is defined by ground-water flow systems. The wetlands are surface-water expressions of larger ground-water watersheds, in which wetlands serve recharge, flow-through, and discharge functions with respect to ground water. The water balance of the wetlands is dominated by precipitation and evaporation. However, the interaction of the wetlands with ground water, although a small part of their water budget, provides the primary control on delivery of major solutes to and from the wetlands. Having monitored these wetlands for more than 25 years, during which time the site had a complete range of climate conditions from drought to deluge, the response of the aquatic communities to a wide variety of climate conditions has been well documented. The Aquatic Systems Continuum extends the model provided by the Wetland Continuum to include rivers and their interaction with ground water. As a result, both ground water and surface water are used to describe terrestrial water flows for all types of aquatic ecosystems. By using the Aquatic Systems Continuum to describe the hydrologic flow paths in all types of terrain, including exchange with atmospheric water, it is possible to design studies, monitoring programs, and management plans for nearly any type of aquatic ecosystem.

  3. Dynamics of active pharmaceutical ingredients loads in a Swiss university hospital wastewaters and prediction of the related environmental risk for the aquatic ecosystems.

    PubMed

    Daouk, Silwan; Chèvre, Nathalie; Vernaz, Nathalie; Widmer, Christèle; Daali, Youssef; Fleury-Souverain, Sandrine

    2016-03-15

    The wastewater contamination of a Swiss university hospital by active pharmaceutical ingredient (API) residues was evaluated with a three months monitoring campaign at the outlet of the main building. Flow-proportional samples were collected with an automatic refrigerated sampler and analyzed for 15 API, including antibiotics, analgesics, antiepileptic and anti-inflammatory drugs, by using a validated LC-MS/MS method. The metals Gd and Pt were also analyzed using ICP-MS. Measured concentrations were compared to the predicted ones calculated after the drug average consumption data obtained from the hospital pharmacy. The hospital contribution to the total urban load was calculated according to the consumption data obtained from city pharmacies. Lastly, the environmental hazard and risk quotients (RQ) related to the hospital fraction and the total urban consumption were calculated. Median concentrations of the 15 selected compounds were ranging from 0.04 to 675 μg/L, with a mean detection frequency of 84%. The ratio between predicted and measured environmental concentrations (PEC/MEC) has shown a good accuracy for 5 out of 15 compounds, revealing over- and under-estimations of the PEC model. Mean daily loads were ranging between 0.01 and 14.2g/d, with the exception of paracetamol (109.7 g/d). The hospital contribution to the total urban loads varied from 2.1 to 100% according to the compound. While taking into account dilution and removal efficiencies in wastewater treatment plant, only the hospital fraction of the antibiotics ciprofloxacin and sulfamethoxazole showed, respectively, a high (RQ>1) and moderate (RQ>0.1) risk for the aquatic ecosystems. Nevertheless, when considering the total urban consumption, 7 compounds showed potential deleterious effects on aquatic organisms (RQ>1): gabapentin, sulfamethoxazole, ciprofloxacin, piperacillin, ibuprofen, diclofenac and mefenamic acid. In order to reduce inputs of API residues originating from hospitals various

  4. Using High-Resolution Models to Predict the Effects of Climate Change on Aquatic Ecosystems in the Crown of the Continent

    NASA Astrophysics Data System (ADS)

    Jones, L.; Muhlfeld, C.; Marshall, L. A.

    2013-12-01

    Climate trends and projections have prompted interest in assessing the thermal sensitivity of aquatic species. How species will adapt and respond to these changes is uncertain, however, climatic and hydrologic changes may shift species habitat distributions and physiological functions both spatially and temporally. This is particularly true for salmonids (e.g., trout, char, and salmon), which are cold-water species strongly influenced by changes in temperature, flow, and physical habitat conditions. Therefore, understanding how habitats are likely to change and how species may respond to changes in climatic conditions is critical for developing conservation and management strategies. The purpose of this study is to develop a high-resolution stream temperature model for the Crown of the Continent Ecosystem (CCE) to simulate potential climate change impacts on thermal regimes throughout the riverscape. A spatially explicit statistical regression model is coupled with high-resolution climate data such as air temperature, precipitation, solar radiation, baseflow and surface runoff. This empirically based model is used to predict daily stream temperatures under historic, current and forecasted climate conditions. The model is parameterized with empirical stream temperature data, which has been gathered from agencies across the region. The current database of empirical stream temperature data consists of over 800 sites throughout the CCE, which provide time series data to the model application. The biological integration and application of this model is on bull trout (Salvelinus confluentus) populations within the CCE. The model will be used to assess species vulnerabilities caused by spatial and temporal changes in stream temperature and hydrology. By evaluating the magnitude, timing and duration of climatic changes on the riverscape, we can more accurately assess potential vulnerabilities of critical life history traits, such as growth potential, spawning migrations

  5. Variability of rRNA Operon Copy Number and Growth Rate Dynamics of Bacillus Isolated from an Extremely Oligotrophic Aquatic Ecosystem

    PubMed Central

    Valdivia-Anistro, Jorge A.; Eguiarte-Fruns, Luis E.; Delgado-Sapién, Gabriela; Márquez-Zacarías, Pedro; Gasca-Pineda, Jaime; Learned, Jennifer; Elser, James J.; Olmedo-Alvarez, Gabriela; Souza, Valeria

    2016-01-01

    The ribosomal RNA (rrn) operon is a key suite of genes related to the production of protein synthesis machinery and thus to bacterial growth physiology. Experimental evidence has suggested an intrinsic relationship between the number of copies of this operon and environmental resource availability, especially the availability of phosphorus (P), because bacteria that live in oligotrophic ecosystems usually have few rrn operons and a slow growth rate. The Cuatro Ciénegas Basin (CCB) is a complex aquatic ecosystem that contains an unusually high microbial diversity that is able to persist under highly oligotrophic conditions. These environmental conditions impose a variety of strong selective pressures that shape the genome dynamics of their inhabitants. The genus Bacillus is one of the most abundant cultivable bacterial groups in the CCB and usually possesses a relatively large number of rrn operon copies (6–15 copies). The main goal of this study was to analyze the variation in the number of rrn operon copies of Bacillus in the CCB and to assess their growth-related properties as well as their stoichiometric balance (N and P content). We defined 18 phylogenetic groups within the Bacilli clade and documented a range of from six to 14 copies of the rrn operon. The growth dynamic of these Bacilli was heterogeneous and did not show a direct relation to the number of operon copies. Physiologically, our results were not consistent with the Growth Rate Hypothesis, since the copies of the rrn operon were decoupled from growth rate. However, we speculate that the diversity of the growth properties of these Bacilli as well as the low P content of their cells in an ample range of rrn copy number is an adaptive response to oligotrophy of the CCB and could represent an ecological mechanism that allows these taxa to coexist. These findings increase the knowledge of the variability in the number of copies of the rrn operon in the genus Bacillus and give insights about the

  6. Variability of rRNA Operon Copy Number and Growth Rate Dynamics of Bacillus Isolated from an Extremely Oligotrophic Aquatic Ecosystem.

    PubMed

    Valdivia-Anistro, Jorge A; Eguiarte-Fruns, Luis E; Delgado-Sapién, Gabriela; Márquez-Zacarías, Pedro; Gasca-Pineda, Jaime; Learned, Jennifer; Elser, James J; Olmedo-Alvarez, Gabriela; Souza, Valeria

    2015-01-01

    The ribosomal RNA (rrn) operon is a key suite of genes related to the production of protein synthesis machinery and thus to bacterial growth physiology. Experimental evidence has suggested an intrinsic relationship between the number of copies of this operon and environmental resource availability, especially the availability of phosphorus (P), because bacteria that live in oligotrophic ecosystems usually have few rrn operons and a slow growth rate. The Cuatro Ciénegas Basin (CCB) is a complex aquatic ecosystem that contains an unusually high microbial diversity that is able to persist under highly oligotrophic conditions. These environmental conditions impose a variety of strong selective pressures that shape the genome dynamics of their inhabitants. The genus Bacillus is one of the most abundant cultivable bacterial groups in the CCB and usually possesses a relatively large number of rrn operon copies (6-15 copies). The main goal of this study was to analyze the variation in the number of rrn operon copies of Bacillus in the CCB and to assess their growth-related properties as well as their stoichiometric balance (N and P content). We defined 18 phylogenetic groups within the Bacilli clade and documented a range of from six to 14 copies of the rrn operon. The growth dynamic of these Bacilli was heterogeneous and did not show a direct relation to the number of operon copies. Physiologically, our results were not consistent with the Growth Rate Hypothesis, since the copies of the rrn operon were decoupled from growth rate. However, we speculate that the diversity of the growth properties of these Bacilli as well as the low P content of their cells in an ample range of rrn copy number is an adaptive response to oligotrophy of the CCB and could represent an ecological mechanism that allows these taxa to coexist. These findings increase the knowledge of the variability in the number of copies of the rrn operon in the genus Bacillus and give insights about the

  7. Phytoplankton and nutrient distributions in a front-eddy area adjacent to the coastal upwelling zone off Concepcion (Chile): implications for ecosystem productivity.

    NASA Astrophysics Data System (ADS)

    Morales, Carmen; Anabalón, Valeria; Hormazábal, Samuel; Cornejo, Marcela; Bento, Joaquim; Silva, Nelson

    2016-04-01

    exportation of coastal communities to the open ocean in this region. We discuss how this interaction might affect ecosystem productivity in the coastal band.

  8. Quantifying aquatic insect deposition from lake to land.

    PubMed

    Dreyer, Jamin; Townsend, Philip A; Hook, James C; Hoekman, David; Vander Zanden, M Jake; Gratton, Claudio

    2015-02-01

    Adjacent ecosystems are influenced by organisms that move across boundaries, such as insects with aquatic larval stages and terrestrial adult stages, which transport energy and nutrients from water to land. However, the ecosystem-level effect of aquatic insects on land has generally been ignored, perhaps because the organisms themselves are individually small. At the naturally productive Lake Mývatn, Iceland, we used two readily measured quantities: total insect emergence from water and relative insect density on land, to demonstrate an approach for estimating aquatic insect deposition (e.g., kg N x m(-2) x yr(-1)) to shore. Estimates from emergence traps between 2008 and 20.11 indicated a range of 0.15-3.7 g x m(-2) x yr(-1), or a whole-lake emergence of 3.1-76 Mg/yr; all masses are given as dry mass. Using aerial infall trap measurements of midge relative abundance over land, we developed a local-maximum decay function model to predict proportional midge deposition with distance from the lake. The dispersal model predicted midge abundance with R2 = 0.89, a pattern consistent among years, with peak midge deposition occurring 20-25 m inland and 70% of midges deposited within 100 m of shore. During a high-midge year (2008), we estimate midge deposition within the first 50 m of shoreline to be 100 kg xha(-1) x yr(-1), corresponding to inputs of 10 kg N x ha(-1) x yr(-1) and 1 kg P x ha(-1) x yr(-1), or about three to five times above background terrestrial N deposition rates. Consistent with elevated N input where midges are most dense, we observed that soil available nitrate in resin bags decreases with increasing distance from the lake. Our approach, generalizable to other systems, shows that aquatic insects can be a major source of nutrients to terrestrial ecosystems and have the capacity to significantly affect ecosystem processes. PMID:26240871

  9. FATE AND EFFECTS OF POLLUTIONS ON AQUATIC ORGANISMS AND ECOSYSTEMS: PROCEEDINGS OF USA-USSR SYMPOSIUM. HELD IN ATHENS, GEORGIA ON OCTOBER 19-21, 1987

    EPA Science Inventory

    The proceedings include reports of modeling: runoff of substances from agricultural watersheds, lacustrine systems, toxic pollutant risk of aquatic organisms, and tributyltin exposure. Social and economic aspects of water quality management are examined and an integrated system f...

  10. Aquatic macroinvertebrates associated with Eichhornia azurea (Swartz) Kunth and relationships with abiotic factors in marginal lentic ecosystems (São Paulo, Brazil).

    PubMed

    Silva, C V; Henry, R

    2013-02-01

    Marginal lakes are characterised by their having high biological diversity due to the presence of aquatic macrophytes in their coastal zones, providing habitats for refuge and food for animal community members. Among the fauna components associated with macrophytes, aquatic macroinvertebrates are important because they are an energy source for predators and fish. In six lakes and two different seasons (March and August 2009), the ecological attributes of aquatic macroinvertebrate community associated with Eichhornia azurea were compared and the controlling environmental factors were identified. Since the attributes of macroinvertebrate community are strictly associated with abiotic variables of each distinct habitat, our hypothesis was that each site associated with the same floating aquatic macrophyte (E. azurea) should have a typical composition and density of organisms. We identified 50 taxa of macroinvertebrates, with greater taxa richness for aquatic insects (37 taxa) divided into eight orders; the order Diptera being the most abundant in the two study periods. On the other hand, higher values of total taxa richness were recorded in August. Dissolved oxygen and pH presented the greatest number of significant positive correlations with the different taxa. The animals most frequently collected in the six lakes in March and August 2009 were Hirudinea, Oligochaeta, Hydrachnidae, Conchostraca, Ostracoda, Noteridae, Ceratopogonidae, Chironomidae, Culicidae, Caenidae, Pleidae, Aeshnidae, Libellulidae, Coenagrionidae and Nematoda. Only densities of Trichoptera, Ostracoda and Conchostraca presented the highest significant differences between lakes in both study periods and considering the composition of macroinvertebrates no significant differences were registered for macroinvertebrate composition. PMID:23644797

  11. Retracted: Using bald eagles to track spatial (1999-2008) and temporal (1987-1992, 1999-2003, and 2004-2008) trends of contaminants in Michigan's aquatic ecosystems.

    PubMed

    Wierda, Michael R; Leith, Katherine F; Grubb, Teryl G; Sikarskie, James G; Best, David A; Bowerman, William

    2016-08-01

    Retraction: 'Using bald eagles to track spatial (1999-2008) and temporal (1987-1992, 1999-2003, and 2004-2008) trends of contaminants in Michigan's aquatic ecosystems' by Michael R. Wierda, Katherine F. Leith, Teryl G. Grubb, James G. Sikarskie, David A. Best, and William Bowerman The above article from Environmental Toxicology and Chemistry, published online on 10 February 2015 in Wiley Online Library (wileyonlinelibrary.com), has been retracted by agreement between the authors, the journal Editor in Chief, G.A. Burton, Jr., SETAC and Wiley Periodicals, Inc. The retraction has been agreed since the authors determined that some of the plasma samples run at Clemson University had failed quality assurance/quality control and were retested. The concentrations have since been corrected and validated. Reference Wierda MR, Leith KF, Grubb TG, Sikarskie JG, Best DA, Bowerman W. 2015. Using bald eagles to track spatial (1999-2008) and temporal (1987-1992, 1999-2003, and 2004-2008) trends of contaminants in Michigan's aquatic ecosystems. Environ ToxicolChem doi:10.1002/etc.2859. PMID:25677528

  12. Project WILD Aquatic K-12 Curriculum and Activity Guide

    ERIC Educational Resources Information Center

    Council for Environmental Education, 2011

    2011-01-01

    The "Project WILD Aquatic K-12 Curriculum and Activity Guide" emphasizes aquatic wildlife and aquatic ecosystems. It is organized in topic units and is based on the Project WILD conceptual framework. Because these activities are designed for integration into existing courses of study, instructors may use one or many Project WILD Aquatic activities…

  13. Biotransformation and accumulation of selenium inside organisms in an engineered aquatic ecosystem designed for bioremediation of Se from agriculture drainage water and brine shrimp production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Excessive selenium (Se) in soils and waters present in the westside of central California was determined to be responsible for ecotoxicities observed in water fowl frequenting large bodies of water, i.e., evaporation ponds. In order to monitor the fate and potentially design an aquatic Se remediatio...

  14. Tracking contaminant flux from aquatic to terrestrial food webs

    EPA Science Inventory

    Aquatic insects provide a critical energy subsidy to riparian food webs, yet their role as vectors of contaminants to terrestrial ecosystems is poorly understood. We investigated aquatic resource utilization and contaminant exposure among riparian invertivores (spiders and herpt...

  15. Why Care About Aquatic Insects: Uses, Benefits, and Services

    EPA Science Inventory

    Mayflies and other aquatic insects are common subjects of ecological research, and environmental monitoring and assessment. However, their important role in protecting and restoring aquatic ecosystems is often challenged, because their benefits and services to humans are not obv...

  16. Different cesium-137 transfers to forest and stream ecosystems.

    PubMed

    Sakai, Masaru; Gomi, Takashi; Negishi, Junjiro N; Iwamoto, Aimu; Okada, Kengo

    2016-02-01

    Understanding the mechanisms of (137)Cs movement across different ecosystems is crucial for projecting the environmental impact and management of nuclear contamination events. Here, we report differential movement of (137)Cs in adjacent forest and stream ecosystems. The food webs of the forest and stream ecosystems in our study were similar, in that they were both dominated by detrital-based food webs and the basal energy source was terrestrial litter. However, the concentration of (137)Cs in stream litter was significantly lower than in forest litter, the result of (137)Cs leaching from litter in stream water. The difference in (137)Cs concentrations between the two types of litter was reflected in the (137)Cs concentrations in the animal community. While the importance of (137)Cs fallout and the associated transfer to food webs has been well studied, research has been primarily limited to cases in a single ecosystem. Our results indicate that there are differences in the flow of (137)Cs through terrestrial and aquatic ecosystems, and that (137)Cs concentrations are reduced in both basal food resources and higher trophic animals in aquatic systems, where primary production is subsidized by a neighboring terrestrial ecosystem. PMID:26629645

  17. CORRESPONDENCE BETWEEN SPATIAL PATTERNS IN FISH ASSEMBLAGES IN OHIO STREAMS AND AQUATIC ECOREGIONS

    EPA Science Inventory

    Land classification systems can be useful for assessing aquatic ecosystems if relationships among them exist. Because the character of an aquatic ecosystem depends to a large extent upon the character of the landscape it drains, spatial patterns in aquatic ecosystems should corre...

  18. Aquatic Environments

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aquatic microbiology can be defined as the study of microorganisms and microbial communities in water environments. Aquatic environments occupy more than 70% of the earth’s surface including oceans, estuaries, rivers, lakes, wetlands, streams, springs, and aquifers. Water is essential for life and m...

  19. Effects of physical and biogeochemical processes on aquatic ecosystems at the groundwater-surface water interface: An evaluation of a sulfate-impacted wild rice stream in Minnesota (USA)

    NASA Astrophysics Data System (ADS)

    Ng, G. H. C.; Yourd, A. R.; Myrbo, A.; Johnson, N.

    2015-12-01

    Significant uncertainty and variability in physical and biogeochemical processes at the groundwater-surface water interface complicate how surface water chemistry affects aquatic ecosystems. Questions surrounding a unique 10 mg/L sulfate standard for wild rice (Zizania sp.) waters in Minnesota are driving research to clarify conditions controlling the geochemistry of shallow sediment porewater in stream- and lake-beds. This issue raises the need and opportunity to carry out in-depth, process-based analysis into how water fluxes and coupled C, S, and Fe redox cycles interact to impact aquatic plants. Our study builds on a recent state-wide field campaign that showed that accumulation of porewater sulfide from sulfate reduction impairs wild rice, an annual grass that grows in shallow lakes and streams in the Great Lakes region of North America. Negative porewater sulfide correlations with organic C and Fe quantities also indicated that lower redox rates and greater mineral precipitation attenuate sulfide. Here, we focus on a stream in northern Minnesota that receives high sulfate loading from iron mining activity yet maintains wild rice stands. In addition to organic C and Fe effects, we evaluate the degree to which streambed hydrology, and in particular groundwater contributions, accounts for the active biogeochemistry. We collect field measurements, spanning the surrounding groundwater system to the stream, to constrain a reactive-transport model. Observations from seepage meters, temperature probes, and monitoring wells delineate upward flow that may lessen surface water impacts below the stream. Geochemical analyses of groundwater, porewater, and surface water samples and of sediment extractions reveal distinctions among the different domains and stream banks, which appear to jointly control conditions in the streambed. A model based on field conditions can be used to evaluate the relative the importance and the spatiotemporal scales of diverse flux and

  20. ECOFATE: A user-friendly environmental fate, bioaccumulation and ecological risk assessment model for contaminants in marine and freshwater aquatic ecosystems -- Applications and validation

    SciTech Connect

    Xin Zhang; Gobas, F.

    1995-12-31

    A Windows based computer simulation model of the environmental fate, food-chain bioaccumulation, toxicity and ecological and human health risks of contaminants is presented. Case studies demonstrating the models application in a lake, a river and a marine fjord are discussed and results are presented illustrating the ability of the model to estimate environmental concentrations over time based on chemical loadings. The case studies involve (1) the temporal response of PCB and mirex concentrations in water, sediments, benthos, fish and bird species of Lake Ontario, (2) the time response of concentrations of chlorinated dioxins and furans in sediments and fish in the Fraser River to reductions in pulp and paper mill discharges and (3) the fate and bioaccumulation of chlorinated dioxins and PAHs in Vancouver Harbour. The purpose of the studies and the model is to assess the capability to predict the environmental fate and bioaccumulation on an ecosystem level, which is of importance for developing site specific environmental quality criteria and to assess the ecosystem`s assimilative capacity by relating whole ecosystem loading allocations to environmental quality criteria.

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

    ERIC Educational Resources Information Center

    Stevenson, R. D.

    These materials were designed to be used by life science students for instruction in the application of physical theory to ecosystem operation. Most modules contain computer programs which are built around a particular application of a physical process. Several modules in the thermodynamic series considered the application of the First Law to…

  2. GEOHYDROLOGY IN SUPPORT OF ECOSYSTEM RESTORATION

    EPA Science Inventory

    The practical framework for ecosystem restoration is the watershed. The structure and function of riparian and wetland areas within the watershed provide water quality services for healthy aquatic ecosystems. Urbanization, agriculture and other pressures can produce point and n...

  3. Quantifying Water Flow within Aquatic Ecosystems Using Load Cell Sensors: A Profile of Currents Experienced by Coral Reef Organisms around Lizard Island, Great Barrier Reef, Australia

    PubMed Central

    Johansen, Jacob L.

    2014-01-01

    Current velocity in aquatic environments has major implications for the diversity, abundance and ecology of aquatic organisms, but quantifying these currents has proven difficult. This study utilises a simple and inexpensive instrument (<$150) to provide a detailed current velocity profile of the coral-reef system around Lizard Island (Great Barrier Reef, Australia) at a spatial and temporal scale relevant to the ecology of individual benthos and fish. The instrument uses load-cell sensors to provide a correlation between sensor output and ambient current velocity of 99%. Each instrument is able to continuously record current velocities to >500 cms−1 and wave frequency to >100 Hz over several weeks. Sensor data are registered and processed at 16 MHz and 10 bit resolution, with a measuring precision of 0.06±0.04%, and accuracy of 0.51±0.65% (mean ±S.D.). Each instrument is also pressure rated to 120 m and shear stresses ≤20 kNm−2 allowing deployment in harsh environments. The instrument was deployed across 27 coral reef sites covering the crest (3 m), mid-slope (6 m) and deep-slope (9 m depth) of habitats directly exposed, oblique or sheltered from prevailing winds. Measurements demonstrate that currents over the reef slope and crest varies immensely depending on depth and exposure: Currents differ up to 9-fold within habitats only separated by 3 m depth and 15-fold between exposed, oblique and sheltered habitats. Comparisons to ambient weather conditions reveal that currents around Lizard Island are largely wind driven. Zero to 22.5 knot winds correspond directly to currents of 0 to >82 cms−1, while tidal currents rarely exceed 5.5 cms−1. Rather, current velocity increases exponentially as a function of wave height (0 to 1.6 m) and frequency (0.54 to 0.20 Hz), emphasizing the enormous effect of wind and waves on organisms in these shallow coral reef habitats. PMID:24421878

  4. Persistency of highly toxic coplanar PCBs in aquatic ecosystems: uptake and release kinetics of coplanar PCBs in green-lipped mussels (Perna viridis Linnaeus).

    PubMed

    Kannan, N; Tanabe, S; Tatsukawa, R; Phillips, D J

    1989-01-01

    The bioaccumulation potential of three highly toxic coplanar PCB isomers [3,3',4,4'-tetrachlorobiphenyl (T(4)CB); 3,3',4,4',5-pentachlorobiphenyl (P(5)CB); and 3,3',4,4',5,5'-hexachlorobiphenyl (H(6)CB)] was investigated using green-lipped mussels (Perna viridis Linnaeus) as a bioindicator, through a transplantation experiment at two locations in Hong Kong waters. By contrast to the relatively rapid uptake and release of many other PCB isomers, the non-ortho chlorine substituted coplanar PCB congeners exhibited slow uptake and clearance. The kinetic parameters of coplanar PCBs based on lipid weight-related data, and the degree of bioaccumulation based on the proportion of coplanar PCBs in total PCBs in mussels, clearly indicate that coplanar PCBs are highly bioaccumulative in lower organisms. On the assumption that mussels are unlikely to be particularly unusual with respect to their bioaccumulation of coplanar PCBs, it appears most likely that these highly toxic and persistent PCB congeners are concentrated by all aquatic organisms, and may reach higher consumers (including humans) in quantities of toxicological concern. PMID:15092492

  5. Effect of emergent aquatic insects on bat foraging in a riparian forest.

    PubMed

    Fukui, Dai; Murakami, Masashi; Nakano, Shigeru; Aoi, Toshiki

    2006-11-01

    other riparian consumers, resource subsidies from streams can directly enhance the performance or population density of riparian-dependent bats. To conserve and manage bat populations, it is important to protect not only forest ecosystems, but also adjacent aquatic systems such as streams. PMID:17032357

  6. Adjacent segment disease.

    PubMed

    Virk, Sohrab S; Niedermeier, Steven; Yu, Elizabeth; Khan, Safdar N

    2014-08-01

    EDUCATIONAL OBJECTIVES As a result of reading this article, physicians should be able to: 1. Understand the forces that predispose adjacent cervical segments to degeneration. 2. Understand the challenges of radiographic evaluation in the diagnosis of cervical and lumbar adjacent segment disease. 3. Describe the changes in biomechanical forces applied to adjacent segments of lumbar vertebrae with fusion. 4. Know the risk factors for adjacent segment disease in spinal fusion. Adjacent segment disease (ASD) is a broad term encompassing many complications of spinal fusion, including listhesis, instability, herniated nucleus pulposus, stenosis, hypertrophic facet arthritis, scoliosis, and vertebral compression fracture. The area of the cervical spine where most fusions occur (C3-C7) is adjacent to a highly mobile upper cervical region, and this contributes to the biomechanical stress put on the adjacent cervical segments postfusion. Studies have shown that after fusion surgery, there is increased load on adjacent segments. Definitive treatment of ASD is a topic of continuing research, but in general, treatment choices are dictated by patient age and degree of debilitation. Investigators have also studied the risk factors associated with spinal fusion that may predispose certain patients to ASD postfusion, and these data are invaluable for properly counseling patients considering spinal fusion surgery. Biomechanical studies have confirmed the added stress on adjacent segments in the cervical and lumbar spine. The diagnosis of cervical ASD is complicated given the imprecise correlation of radiographic and clinical findings. Although radiological and clinical diagnoses do not always correlate, radiographs and clinical examination dictate how a patient with prolonged pain is treated. Options for both cervical and lumbar spine ASD include fusion and/or decompression. Current studies are encouraging regarding the adoption of arthroplasty in spinal surgery, but more long

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

    PubMed

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

    2014-07-15

    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

  8. Aquatic Sediments.

    ERIC Educational Resources Information Center

    Sanville, W. D.; And Others

    1978-01-01

    Presents a literature review of aquatic sediments and its effect upon water quality, covering publications of 1976-77. This review includes: (1) sediment water interchange; (2) chemical and physical characterization; and (3) heavy water in sediments. A list of 129 references is also presented. (HM)

  9. Microbial mediated retention/transformation of organic and inorganic materials in freshwater and marine ecosystems

    EPA Science Inventory

    Aquatic ecosystems are globally connected by hydrological and biogeochemical cycles. Microorganisms inhabiting aquatic ecosystems form the basis of food webs, mediate essential element cycles, decompose natural organic matter, transform inorganic nutrients and metals, and degrad...

  10. Toxicity assessment of boron (B) by Lemna minor L. and Lemna gibba L. and their possible use as model plants for ecological risk assessment of aquatic ecosystems with boron pollution.

    PubMed

    Gür, Nurcan; Türker, Onur Can; Böcük, Harun

    2016-08-01

    As many of the metalloid-based pollutants, the boron (B) toxicity issues have aroused more and more global attentions, especially concerning drinking water sources which flow through boron-rich areas. Therefore, feasible and innovative approaches are required in order to assess B toxicity in aquatic ecosystems. In this study, the toxic effects of B on Lemna minor L. and Lemna gibba L. were investigated using various endpoints including number of fronds, growth rates, dry biomass and antioxidants enzymatic activities. Lemna species were exposed to B concentrations of 2 (control), 4, 8, 16, 32, 64 and 128 mg L(-1) for a test period of 7 days. The results demonstrated that plant growth was significantly reduced when the B concentration reached 16 mg L(-1). Furthermore, our results also concluded that among the antioxidative enzymes, SOD, APX and GPX can serve as important biomarkers for B-rich environment. The present results suggested that L. minor and L. gibba are very useful model plants for phytoremediation of low-B contaminated wastewater and they are also suitable options for B biomonitoring due to high phototoxic sensitivity against B. In this respect, the scientific insight of the present study is to fill the gaps in the research about the use of L. minor and L. gibba in ecotoxicological research associated with B toxicity. PMID:27192627

  11. Using bald eagles to track spatial (1999-2008) and temporal (1987-1992, 1999-2003, and 2004-2008) trends of contaminants in Michigan's aquatic ecosystems.

    PubMed

    Wierda, Michael R; Leith, Katherine F; Roe, Amy S; Grubb, Teryl G; Sikarskie, James G; Best, David A; Pittman, H Tyler; Fuentes, Latice; Simon, Kendall L; Bowerman, William

    2016-08-01

    The bald eagle (Haliaeetus leucocephalus) is an extensively researched tertiary predator. Studies have delineated information about its life history and the influences of various stressors on its reproduction. Due to the bald eagle's position at the top of the food web, it is susceptible to biomagnification of xenobiotics. The Michigan Department of Environmental Quality implemented a program in 1999 to monitor persistent chemicals including polychlorinated biphenols (PCBs) and dichlorodiphenyltrichloroethane (DDE). The objectives of the present study were to evaluate spatial and temporal trends of PCBs and organochlorine pesticides in nestling bald eagles of Michigan. The authors' study found that concentrations of PCBs and DDE were higher in Great Lakes areas with Lakes Michigan and Lake Huron having the highest concentrations of DDE and Lake Erie having the highest concentrations of PCBs. Temporally (1987-1992, 1999-2003, and 2004-2008) the present study found declines in PCB and DDE concentrations with a few exceptions. Continued monitoring of Michigan bald eagle populations is suggested for a couple of reasons. First, nestling blood contaminant levels are an appropriate method to monitor ecosystem contaminant levels. Second, from 1999 to 2008 PCB and DDE concentrations for 30% and 40%, respectively, of the nestling eagles sampled were above the no observable adverse effect level (NOAEL) for bald eagles. Lastly, with the continued development and deployment of new chemistries a continuous long term monitoring program is an invaluable resource. Environ Toxicol Chem 2016;35:1995-2002. © 2016 SETAC. PMID:27442160

  12. Commentary on effects of anthropogenic and natural organic chemicals on development, swimming behavior, and reproduction of Daphnia, a key member of aquatic ecosystems.

    PubMed Central

    Dodson, S I; Hanazato, T

    1995-01-01

    Because of their trophodynamic role, small invertebrates are often critical components of ecosystems. An especially important group of freshwater invertebrates is the water fleas of the genus Daphnia. These animals are often the dominant herbivores in lakes and ponds. They play a key role in determining water clarity (by grazing on algae) and they are an important part of the diet of fish. Natural chemical signals (kairomones) produced by predators affect the development, life history strategy, and behavior of zooplankton. Laboratory studies of anthropogenic chemicals that have biological activity (xenobiotics), such as the insecticide carbaryl, have demonstrated effects of concentrations in the 1 to 5 ppb range on Daphnia development, growth rate, and swimming behavior in our laboratory experiments. Low concentrations of carbaryl inhibit growth and reproduction and delay maturation, whereas survivorship was not effected. These sublethal exposures to carbaryl reduced Daphnia population growth rate (productivity) by about 15% (at 5 ppb), enough to have significant ecological effects on the rest of the lake community. The insecticide carbaryl showed synergistic interactions with natural chemicals associated with predators (kairomones) that modify Daphnia development and life history characteristic. In addition, there were complex synergisms between carbaryl, the predator odors, and oxygen concentration (low oxygen concentration can be either a natural environmental stress or an anthropogenic stress). Daphnia produce males facultatively, usually in late fall; at other times, reproduction is asexual.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7556027

  13. Multivariate and phylogenetic analyses assessing the response of bacterial mat communities from an ancient oligotrophic aquatic ecosystem to different scenarios of long-term environmental disturbance.

    PubMed

    Pajares, Silvia; Souza, Valeria; Eguiarte, Luis E

    2015-01-01

    Understanding the response of bacterial communities to environmental change is extremely important in predicting the effect of biogeochemical modifications in ecosystem functioning. The Cuatro Cienegas Basin is an ancient oasis in the Mexican Chihuahuan desert that hosts a wide diversity of microbial mats and stromatolites that have survived in extremely oligotrophic pools with nearly constant conditions. However, thus far, the response of these unique microbial communities to long-term environmental disturbances remains unexplored. We therefore studied the compositional stability of these bacterial mat communities by using a replicated (3x) mesocosm experiment: a) Control; b) Fluct: fluctuating temperature; c) 40C: increase to 40 ºC; d) UVplus: artificial increase in UV radiation; and f) UVmin: UV radiation protection. In order to observe the changes in biodiversity, we obtained 16S rRNA gene clone libraries from microbial mats at the end of the experiment (eight months) and analyzed them using multivariate and phylogenetic tools. Sequences were assigned to 13 major lineages, among which Cyanobacteria (38.8%) and Alphaproteobacteria (25.5%) were the most abundant. The less extreme treatments (Control and UVmin) had a more similar composition and distribution of the phylogenetic groups with the natural pools than the most extreme treatments (Fluct, 40C, and UVplus), which showed drastic changes in the community composition and structure, indicating a different community response to each environmental disturbance. An increase in bacterial diversity was found in the UVmin treatment, suggesting that protected environments promote the establishment of complex bacterial communities, while stressful environments reduce diversity and increase the dominance of a few Cyanobacterial OTUs (mainly Leptolyngbya sp) through environmental filtering. Mesocosm experiments using complex bacterial communities, along with multivariate and phylogenetic analyses of molecular data, can

  14. Multivariate and Phylogenetic Analyses Assessing the Response of Bacterial Mat Communities from an Ancient Oligotrophic Aquatic Ecosystem to Different Scenarios of Long-Term Environmental Disturbance

    PubMed Central

    Pajares, Silvia; Souza, Valeria; Eguiarte, Luis E.

    2015-01-01

    Understanding the response of bacterial communities to environmental change is extremely important in predicting the effect of biogeochemical modifications in ecosystem functioning. The Cuatro Cienegas Basin is an ancient oasis in the Mexican Chihuahuan desert that hosts a wide diversity of microbial mats and stromatolites that have survived in extremely oligotrophic pools with nearly constant conditions. However, thus far, the response of these unique microbial communities to long-term environmental disturbances remains unexplored. We therefore studied the compositional stability of these bacterial mat communities by using a replicated (3x) mesocosm experiment: a) Control; b) Fluct: fluctuating temperature; c) 40C: increase to 40 ºC; d) UVplus: artificial increase in UV radiation; and f) UVmin: UV radiation protection. In order to observe the changes in biodiversity, we obtained 16S rRNA gene clone libraries from microbial mats at the end of the experiment (eight months) and analyzed them using multivariate and phylogenetic tools. Sequences were assigned to 13 major lineages, among which Cyanobacteria (38.8%) and Alphaproteobacteria (25.5%) were the most abundant. The less extreme treatments (Control and UVmin) had a more similar composition and distribution of the phylogenetic groups with the natural pools than the most extreme treatments (Fluct, 40C, and UVplus), which showed drastic changes in the community composition and structure, indicating a different community response to each environmental disturbance. An increase in bacterial diversity was found in the UVmin treatment, suggesting that protected environments promote the establishment of complex bacterial communities, while stressful environments reduce diversity and increase the dominance of a few Cyanobacterial OTUs (mainly Leptolyngbya sp) through environmental filtering. Mesocosm experiments using complex bacterial communities, along with multivariate and phylogenetic analyses of molecular data, can

  15. Assessment of multi-chemical pollution in aquatic ecosystems using toxic units: compound prioritization, mixture characterization and relationships with biological descriptors.

    PubMed

    Ginebreda, Antoni; Kuzmanovic, Maja; Guasch, Helena; de Alda, Miren López; López-Doval, Julio C; Muñoz, Isabel; Ricart, Marta; Romaní, Anna M; Sabater, Sergi; Barceló, Damià

    2014-01-15

    Chemical pollution is typically characterized by exposure to multiple rather than to single or a limited number of compounds. Parent compounds, transformation products and other non-targeted compounds yield mixtures whose composition can only be partially identified by monitoring, while a substantial proportion remains unknown. In this context, risk assessment based on the application of additive ecotoxicity models, such as concentration addition (CA), is rendered somewhat misleading. Here, we show that ecotoxicity risk information can be better understood upon consideration of the probabilistic distribution of risk among the different compounds. Toxic units of the compounds identified in a sample fit a lognormal probability distribution. The parameters characterizing this distribution (mean and standard deviation) provide information which can be tentatively interpreted as a measure of the toxic load and its apportionment among the constituents in the mixture (here interpreted as mixture complexity). Furthermore, they provide information for compound prioritization tailored to each site and enable prediction of some of the functional and structural biological variables associated with the receiving ecosystem. The proposed approach was tested in the Llobregat River basin (NE Spain) using exposure and toxicity data (algae and Daphnia) corresponding to 29 pharmaceuticals and 22 pesticides, and 5 structural and functional biological descriptors related to benthic macroinvertebrates (diversity, biomass) and biofilm metrics (diatom quality, chlorophyll-a content and photosynthetic capacity). Aggregated toxic units based on Daphnia and algae bioassays provided a good indication of the pollution pattern of the Llobregat River basin. Relative contribution of pesticides and pharmaceuticals to total toxic load was variable and highly site dependent, the latter group tending to increase its contribution in urban areas. Contaminated sites' toxic load was typically dominated by

  16. Protecting aquatic resources: an ecologist's perspective

    SciTech Connect

    Giddings, J.M.

    1984-04-17

    Because natural populations are linked by a variety of ecological interactions (e.g., predation and competition), the response of any particular population to chemical exposure depends on how the rest of the ecosystem is affected. Mathematical models and field experiments demonstrate that such interactions can amplify or diminish the impacts of contaminants on populations. When direct toxic effects result in persistent, significant changes in some parts of an ecosystem, other populations in the ecosystem become vulnerable to indirect effects. Protection of aquatic populations, then, requires protection of aquatic ecosystems. The threshold of persistent, significant damage to an ecosystem is a distinct discontinuity in the gradient of ecosystem response to increasing chemical exposure. The safe level of exposure for an aquatic ecosystem can be determined experimentally using microcosms or field enclosures. It is hypothesized that safe exposure levels for ecosystems are usually near the lower end of the chronic toxicity range for single species. Data on chemical effects in ecosystem are needed in order to calibrate standard bioassays and to verify the accuracy of methods for extrapolating from bioassay results to nature. 16 references, 1 figure.

  17. Pesticide runoff from energy crops: A threat to aquatic invertebrates?

    PubMed

    Bunzel, Katja; Schäfer, Ralf B; Thrän, Daniela; Kattwinkel, Mira

    2015-12-15

    The European Union aims to reach a 10% share of biofuels in the transport sector by 2020. The major burden is most likely to fall on already established annual energy crops such as rapeseed and cereals for the production of biodiesel and bioethanol, respectively. Annual energy crops are typically cultivated in intensive agricultural production systems, which require the application of pesticides. Agricultural pesticides can have adverse effects on aquatic invertebrates in adjacent streams. We assessed the relative ecological risk to aquatic invertebrates associated with the chemical pest management from six energy crops (maize, potato, sugar beet, winter barley, winter rapeseed, and winter wheat) as well as from mixed cultivation scenarios. The pesticide exposure related to energy crops and cultivation scenarios was estimated as surface runoff for 253 small stream sites in Central Germany using a GIS-based runoff potential model. The ecological risk for aquatic invertebrates, an important organism group for the functioning of stream ecosystems, was assessed using acute toxicity data (48-h LC50 values) of the crustacean Daphnia magna. We calculated the Ecological Risk from potential Pesticide Runoff (ERPR) for all three main groups of pesticides (herbicides, fungicides, and insecticides). Our findings suggest that the crops potato, sugar beet, and rapeseed pose a higher ecological risk to aquatic invertebrates than maize, barley, and wheat. As maize had by far the lowest ERPR values, from the perspective of pesticide pollution, its cultivation as substrate for the production of the gaseous biofuel biomethane may be preferable compared to the production of, for example, biodiesel from rapeseed. PMID:26282752

  18. Linking water quality guidelines to the natural characteristics of catchments in order to support distinct aquatic ecosystems: Water quality guidelines for suspended particulate matter

    NASA Astrophysics Data System (ADS)

    Bilotta, G. S.; Grove, M. K.; Harrison, C.; Joyce, C. B.; Peacock, C.

    2012-12-01

    The natural characteristics of a catchment provide a template that controls the background rates of geomorphological processes operating within that catchment, which in-turn determines the background physico-chemical and hydro-morphological characteristics of the catchment's surface waters. Large differences in the natural characteristics of catchments (e.g. geology, topography, climate), lead to unique physico-chemical and hydro-morphological conditions that support unique freshwater communities. However, this uniqueness is not always recognised in international water quality guidelines, which often attempt to apply blanket water-quality guidelines to 'protect' a wide range of ecosystems. In this paper we investigate the natural characteristics that control background concentrations of suspended particulate matter (SPM - including nano-scale particles to sand-sized sediments), which is a well-known cause of ecological degradation. At present, the management of SPM is hampered by a lack of understanding of the SPM conditions that water quality managers should aim to achieve in contrasting environments in order to support good ecological status. To address this, in this paper we examine the SPM preferences of contrasting biological communities that are in reference condition (minimal anthropogenic disturbance and high ecological status). We analyse historical SPM data collected on a monthly basis from a wide range of reference-condition temperate environments (638 stream/river sites comprising 42 different biological community-types). This analysis reveals that there are statistically significant differences (One-way ANOVA p < 0.001) between the background SPM concentrations observed in contrasting communities that are in reference condition. Mean background SPM concentrations for contrasting communities ranged from 1.7 to 26.2 mg L-1 (i.e. more than a 15-fold difference). We propose a model for predicting environment-specific water quality guidelines for SPM. In

  19. Spatial and temporal water quality variability in aquatic habitats of a cultivated floodplain

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Floodplains of lowland rivers contain diverse aquatic habitats that provide valuable ecosystem services, but are perturbed when intensively cultivated. Hydrologic, water quality and biological (fish) conditions in five aquatic habitats along the Coldwater River, Mississippi were measured over four ...

  20. Nitrous oxide emission by aquatic macrofauna

    PubMed Central

    Stief, Peter; Poulsen, Morten; Nielsen, Lars Peter; Brix, Hans; Schramm, Andreas

    2009-01-01

    A large variety of aquatic animals was found to emit the potent greenhouse gas nitrous oxide when nitrate was present in the environment. The emission was ascribed to denitrification by ingested bacteria in the anoxic animal gut, and the exceptionally high N2O-to-N2 production ratio suggested delayed induction of the last step of denitrification. Filter- and deposit-feeding animal species showed the highest rates of nitrous oxide emission and predators the lowest, probably reflecting the different amounts of denitrifying bacteria in the diet. We estimate that nitrous oxide emission by aquatic animals is quantitatively important in nitrate-rich aquatic environments like freshwater, coastal marine, and deep-sea ecosystems. The contribution of this source to overall nitrous oxide emission from aquatic environments might further increase because of the projected increase of nitrate availability in tropical regions and the numeric dominance of filter- and deposit-feeders in eutrophic ecosystems. PMID:19255427

  1. Macrophyte disturbance alters aquatic surface microlayer structure, metabolism, and fate.

    PubMed

    Seliskar, Denise M; Gallagher, John L

    2014-03-01

    Macrophytes drive the functioning of many salt marsh ecosystem components. We questioned how temporary clearing of the macrophyte community, during restoration, would impact processes at the scale of the aquatic surface microlayer. Development, deposition, and breakup of the tidal creek surface microlayer were followed over tidal cycles seasonally in a cleared "former" Phragmites marsh and an adjacent restored Spartina marsh. Metabolic and physical processes of the mobile surface microlayers and underlying water were compared, along with distribution of organic and inorganic components onto simulated plant stems. In July and October, chlorophyll-a quantities were less on simulated stems in the cleared site than in the restored site. The aquatic microlayer in the cleared site creek exhibited lower photosynthesis and respiration rates, fewer diatoms and green algae, and less chlorophyll-a. There was a lower concentration (250 times) and reduced diversity of fatty acids in the surface microlayer of the cleared site, reflecting a smaller and less diverse microbial community and reduced food resources. Fiddler crab activity was an order of magnitude higher where macrophytes had been cleared. Their consumption of edaphic algae on the mud surface may account for the reduced algae and other organics in the creek surface microlayer, thus representing a redirection of this food resource from creek consumers. Overall, there were less total particulates in the creek surface microlayer at the cleared site, and they dropped out of the surface microlayer sooner in the tidal cycle, resulting in a lower sediment load available for deposit onto marsh surfaces. PMID:24135995

  2. The aquatic ecotoxicology of triazine herbicides

    SciTech Connect

    Giddings, J.M.

    1996-10-01

    Triazine herbicides control plant growth by inhibiting photophosphorylation, but typically do not cause permanent cell damage or death. Effects on aquatic plants are reversible; photosynthesis resumes when the herbicide disappears from the water, and sometimes even while it is still present. Effects on aquatic plant communities are further ameliorated by species replacements, so the communities as a whole are less sensitive than their most sensitive species. Atrazine, a representative triazine herbicide, is toxic to aquatic plants (algae and macrophytes) at concentrations in the range of 20 to 200 {mu}g/L or less. Aquatic invertebrates and fish are much less sensitive than plants, with acute toxicity occurring at 1000 {mu}g/L or higher. Ecologically significant effects in aquatic ecosystems are likely only if plant communities are severely damaged by prolonged exposure to high atrazine concentrations.

  3. Phytoremediation potential of aquatic macrophyte, Azolla.

    PubMed

    Sood, Anjuli; Uniyal, Perm L; Prasanna, Radha; Ahluwalia, Amrik S

    2012-03-01

    Aquatic macrophytes play an important role in the structural and functional aspects of aquatic ecosystems by altering water movement regimes, providing shelter to fish and aquatic invertebrates, serving as a food source, and altering water quality by regulating oxygen balance, nutrient cycles, and accumulating heavy metals. The ability to hyperaccumulate heavy metals makes them interesting research candidates, especially for the treatment of industrial effluents and sewage waste water. The use of aquatic macrophytes, such as Azolla with hyper accumulating ability is known to be an environmentally friendly option to restore polluted aquatic resources. The present review highlights the phytoaccumulation potential of macrophytes with emphasis on utilization of Azolla as a promising candidate for phytoremediation. The impact of uptake of heavy metals on morphology and metabolic processes of Azolla has also been discussed for a better understanding and utilization of this symbiotic association in the field of phytoremediation. PMID:22396093

  4. Multi-Ecosystem Assessment of Mercury Bioaccumulation in Fishes: Habitat, Landscape, and Biogeochemical Drivers of Fish Mercury

    NASA Astrophysics Data System (ADS)

    Eagles-Smith, C.; Ackerman, J.; Herring, G.; Willacker, J.; Flanagan, C.

    2014-12-01

    Mercury (Hg) is a globally distributed contaminant that threatens ecosystem health across aquatic environments. The complexity of the Hg cycle and its primary drivers, coupled with dynamic food web processes that govern biomagnification, result in marked spatial variability in Hg bioaccumulation across aquatic ecosystems. However, it is unclear if patterns of bioaccumulation are consistent in magnitude and direction across ecosystem types. We synthesized data from several studies spanning more than 200 individual sites, comprising four distinct ecosystem classifications (estuaries, sub-alpine lakes, rivers, and managed wetlands). Within each ecosystem, we compared fish Hg concentrations among replicated sub-habitats and also evaluated the influence of land use, landscape composition, and biogeochemical drivers on fish Hg concentrations. We found substantial variability in fish Hg concentrations among adjacent sub-habitats within ecosystems. In estuarine environments, fish Hg concentrations were 7.4x higher in seasonal-saline wetlands than adjacent tidal wetland habitats. In riverine alcoves, preliminary data suggest that fish Hg concentrations were 1.5x higher than in fishes from paired mainstem river habitat. Among managed wetland habitats, fish Hg concentrations in rice fields were 2x higher than those in managed seasonal wetlands that were subjected to identical wetting and drying patterns. Across ecosystems, dissolved organic carbon (DOC) concentrations in surface waters were consistently correlated with fish Hg concentrations, highlighting its importance in Hg methylation and transport processes. Yet, the strength and direction of the relationships varied among habitat types. For example, fish Hg concentrations were positively correlated with DOC concentrations in riverine environments, whereas we found a negative correlation in alpine lakes. Instead, the most important determinant of fish Hg concentrations in alpine lakes was conifer tree density within a

  5. Aquatic invasive species: Lessons from cancer research

    USGS Publications Warehouse

    Sepulveda, Adam; Ray, Andrew; Al-Chokhachy, Robert K.; Muhlfeld, Clint C.; Gresswell, Robert E.; Gross, Jackson A.; Kershner, Jeffrey L.

    2014-01-01

    Aquatic invasive species are disrupting ecosystems with increasing frequency. Successful control of these invasions has been rare: Biologists and managers have few tools for fighting aquatic invaders. In contrast, the medical community has long worked to develop tools for preventing and fighting cancer. Its successes are marked by a coordinated research approach with multiple steps: prevention, early detection, diagnosis, treatment options and rehabilitation. The authors discuss how these steps can be applied to aquatic invasive species, such as the American bullfrog (Lithobates catesbeianus), in the Northern Rocky Mountain region of the United States, to expedite tool development and implementation along with achievement of biodiversity conservation goals.

  6. Evaluation of graphite for environmental toxicity using the standard aquatic microcosm. Technical report, June 1986-March 1987

    SciTech Connect

    Landis, W.G.; Chester, N.A.; Haley, M.V.; Johnson, D.W.; Tauber, R.M.

    1988-08-01

    The impact of a graphite dust on an aquatic ecosystem model, the Standard Aquatic microcosm (SAM), was investigated. Graphite dust produced effects that resembled eutrophication in that a diversity decreased, ammonia increased, and a photosynthesis/respiration ratio of less than one was observed in the highest concentration. Compared to brass dust, graphite has much less potential to adversely impact aquatic ecosystems.

  7. Human - Ecosystem Interactions: The Case of Mercury

    EPA Science Inventory

    Human and ecosystem exposure studies evaluate exposure of sensitive and vulnerable populations. We will discuss how ecosystem exposure modeling studies completed for input into the US Clean Air Mercury Rule (CAMR) to evaluate the response of aquatic ecosystems to changes in mercu...

  8. Application of remote sensing in aquatic ecosystems

    NASA Astrophysics Data System (ADS)

    Yousef, Foad

    I utilized state the art remote sensing and GIS (Geographical Information System) techniques to study large scale biological, physical and ecological processes of coastal, nearshore, and offshore waters of Lake Michigan and Lake Superior. These processes ranged from chlorophyll alpha and primary production time series analysies in Lake Michigan to coastal stamp sand threats on Buffalo Reef in Lake Superior. I used SeaWiFS (Sea-viewing Wide Field-of-view Sensor) satellite imagery to trace various biological, chemical and optical water properties of Lake Michigan during the past decade and to investigate the collapse of early spring primary production. Using spatial analysis techniques, I was able to connect these changes to some important biological processes of the lake (quagga mussels filtration). In a separate study on Lake Superior, using LiDAR (Light Detection and Ranging) and aerial photos, we examined natural coastal erosion in Grand Traverse Bay, Michigan, and discussed a variety of geological features that influence general sediment accumulation patterns and interactions with migrating tailings from legacy mining. These sediments are moving southwesterly towards Buffalo Reef, creating a threat to the lake trout and lake whitefish breeding ground.

  9. Planning aquatic ecosystem restoration monitoring programs

    SciTech Connect

    Thom, R.M.; Wellman, K.F.

    1997-01-01

    This study was conducted as part of the Evaluation of Environmental Investments Research Program (EEIRP). The EEIRP is sponsored by the US Army Corps of Engineers. The objectives of this work are to (1) identify relevant approaches and features for environmental investment measures to be applied throughout the project life; (2) develop methods to access the effectiveness of the approach or feature for providing the intended environmental output; (3) develop and provide guidance for formulating environmental projects; and (4) provide guidance for formulating and identifying relevant cost components of alternate restoration plans.

  10. Metabolomic Approaches for Characterizing Aquatic Ecosystems

    EPA Science Inventory

    Metabolomics is becoming a well-established tool for studying how organisms, such as fish, respond to various stressors. For example, the literature is rich with laboratory studies involving analysis of samples from organisms exposed to individual chemical toxicants. These studie...

  11. A macrophyte submodel for aquatic ecosystems

    USGS Publications Warehouse

    Collins, Carol Desormeau; Wlosinski, Joseph H.

    1989-01-01

    A macrophyte submodel has been incorporated and tested in CE-QUAL-R1, a one-dimensional, vertically averaged model of reservoir water quality. A quasi two-dimensional scheme was necessary to represent the spatial relationship of macrophytes in reservoirs adequately. The macrophyte processes modeled were photosynthesis, dark respiration, excretion and nonpredatory mortality. Process equations for photosynthesis as a function of light and temperature, and dark respiration as a function of temperature were tested using data from laboratory studies. The submodel was field tested, along with other components of CE-QUAL-R1, using data collected at Eau Galle Reservoir, WI, U.S.A.

  12. Effects of Bt-transgenic rice cultivation on planktonic communities in paddy fields and adjacent ditches.

    PubMed

    Liu, Yongbo; Liu, Fang; Wang, Chao; Quan, Zhanjun; Li, Junsheng

    2016-09-15

    The non-target effects of transgenic plants are issues of concern; however, their impacts in cultivated agricultural fields and adjacent natural aquatic ecosystems are poorly understood. We conducted field experiments during two growing seasons to determine the effects of cultivating Bacillus thuringiensis (Bt)-transgenic rice on the phytoplankton and zooplankton communities in a paddy field and an adjacent ditch. Bt toxin was detected in soil but not in water. Water quality was not significantly different between non-Bt and Bt rice fields, but varied among up-, mid- and downstream locations in the ditch. Cultivation of Bt-transgenic rice had no effects on zooplankton communities. Phytoplankton abundance and biodiversity were not significantly different between transgenic and non-transgenic rice fields in 2013; however, phytoplankton were more abundant in the transgenic rice field than in the non-transgenic rice field in 2014. Water quality and rice type explained 65.9% and 12.8% of this difference in 2014, respectively. Phytoplankton and zooplankton were more abundant in mid- and downstream, than upstream, locations in the ditch, an effect that we attribute to water quality differences. Thus, the release of Bt toxins into field water during the cultivation of transgenic crops had no direct negative effects on plankton community composition, but indirect effects that alter environmental conditions should be taken into account during the processes of management planning and policymaking. PMID:27219503

  13. Aquatic biodiversity and the electric utility industry

    SciTech Connect

    Olmsted, L.L.; Bolin, J.W.

    1996-11-01

    Results for a 1995 survey of utility company biologists indicate that aquatic biodiversity is an emerging and poorly understood issue. As a result, there is some confusion about what aquatic biodiversity actually is, and how we can best conserve it. Only one fourth (24%) of the respondents said their company has a stated environmental policy that addresses biodiversity. Many respondents indicate that over the years they have not specially managed for biodiversity, but have been doing that through their efforts to assure balanced indigenous populations. While regulations are still the major driver for biological work, an increasing number of companies are involved in voluntary partnerships in managing water resources. Of these voluntary partnerships, 70% have biodiversity as a goal. Biodiversity is becoming an increasingly common subject of study, and a vast majority (75%) of the respondents suggested is should be a goal for utility for resource management. Conservation of aquatic biodiversity is a complex task, and to date most aquatic efforts have been directed toward fish and macroinvertebrates. Ecological research and technological development performed by the utility industry have resulted in a number of successful biopreservation and biorestoration success stories. A common theme to preserving or enhancing aquatic biodiversity is preserving aquatic habitat. Increasingly, ecosystem management is touted as the most likely approach to achieve success in preserving aquatic biodiversity. Several utilities are conducting progressive work in implementing ecosystem management. This paper presents the potential interactions between power plants and biodiversity, and overview of aquatic biodiversity preservations efforts within the electric utility industry, more detail on the results of the survey, and recent initiatives in ecosystem management. 17 refs., 1 tab.

  14. ECOSYSTEM RESPONSES TO INCREASES IN SOLAR ULTRAVIOLET-B RADIATION

    EPA Science Inventory

    Terrestrial and aquatic ecosystems represent complex, interconnected assemblages of organisms which Interact with each other and their physical environment. n understanding of how ecosystems will respond to subtle changes in the environment, as would occur under stratospheric ozo...

  15. VASCULAR PLANTS AS ENGINEERS OF OXYGEN IN AQUATIC SYSTEMS

    EPA Science Inventory

    The impact of organisms on oxygen is one of the most dramatic examples of ecosystem engineering on Earth. In aquatic systems, which have much lower oxygen concentrations than the atmosphere, vascular aquatic plants can affect oxygen concentrations significantly not only on long t...

  16. Managed island ecosystems

    USGS Publications Warehouse

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

    2016-01-01

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

  17. Use of enzymatic tools for biomonitoring inorganic pollution in aquatic sediments: a case study (Bor, Serbia)

    PubMed Central

    2013-01-01

    Background Sediment bacterial communities are key players in biogeochemical cycling of elements in the aquatic environment. Copper mining, smelting, and processing operations located in Bor area (Serbia) are major environmental hot spots in the lower Danube Basin and Western Balkans. In the present study, we evaluate the influence of trace element (TE) concentration in sediments and physico-chemical properties of water on sediment microbial communities in water streams adjacent to the Copper Smelter Complex Bor (RTB Bor, Serbia). The degree to which metabolic activities of bacterial biota inhabiting differently polluted sites is inhibited by inorganic pollution were compared using selected enzymatic bioindicators. Results Cu, Zn, Pb, and As concentrations systematically exceeded the target values for metal loadings in aquatic sediments. Water electrical conductivity (WEC) followed the same pattern of spatial variation, irrespective of season. Interestingly, the most intense enzymatic activity occurred at the reference site although this site showed the greatest TE levels in aquatic sediments. Catalase activity (CA), potential dehydrogenase activity (PDA), actual dehydrogenase activity (ADA), urease activity (UA), and phosphatase activity (PA) in aquatic sediments displayed heterogeneous patterns of spatio-temporal variation. Inorganic pollution greatly affected CA, ADA, and PDA, but much less so UA and PA. Canonical correlation analysis showed that pH and WEC were the strongest determinants of enzymatic activity in bacterial biota, with the latter variable being reversely correlated with the enzymatic indicator of sediment quality (EISQ). The median values of EISQ increased with distance from the major sources of pollution. In addition, it was found that sites with different degrees of inorganic pollution can be appropriately classified by applying cluster analysis to EISQ, TE levels in sediments, and physico-chemical properties of water. Conclusions Because EISQ

  18. Thermal Pollution Impact upon Aquatic Life.

    ERIC Educational Resources Information Center

    Shiomoto, Gail T.; Olson, Betty H.

    1978-01-01

    Conventional and nuclear power plants release waste heat to cooling water which then returns to receiving bodies of surface water. This thermal pollution causes a variety of effects in the aquatic ecosystem. More must be learned about these effects to ensure adequate regulation of thermal discharges. (RE)

  19. Evaluation of Current Approaches to Stream Classification and a Heuristic Guide to Developing Classifications of Integrated Aquatic Networks

    NASA Astrophysics Data System (ADS)

    Melles, S. J.; Jones, N. E.; Schmidt, B. J.

    2014-03-01

    Conservation and management of fresh flowing waters involves evaluating and managing effects of cumulative impacts on the aquatic environment from disturbances such as: land use change, point and nonpoint source pollution, the creation of dams and reservoirs, mining, and fishing. To assess effects of these changes on associated biotic communities it is necessary to monitor and report on the status of lotic ecosystems. A variety of stream classification methods are available to assist with these tasks, and such methods attempt to provide a systematic approach to modeling and understanding complex aquatic systems at various spatial and temporal scales. Of the vast number of approaches that exist, it is useful to group them into three main types. The first involves modeling longitudinal species turnover patterns within large drainage basins and relating these patterns to environmental predictors collected at reach and upstream catchment scales; the second uses regionalized hierarchical classification to create multi-scale, spatially homogenous aquatic ecoregions by grouping adjacent catchments together based on environmental similarities; and the third approach groups sites together on the basis of similarities in their environmental conditions both within and between catchments, independent of their geographic location. We review the literature with a focus on more recent classifications to examine the strengths and weaknesses of the different approaches. We identify gaps or problems with the current approaches, and we propose an eight-step heuristic process that may assist with development of more flexible and integrated aquatic classifications based on the current understanding, network thinking, and theoretical underpinnings.

  20. Using stable isotope analysis in stream mesocosms to study potential effects of environmental chemicals on aquatic-terrestrial subsidies.

    PubMed

    Wieczorek, Matthias V; Kötter, Denise; Gergs, René; Schulz, Ralf

    2015-09-01

    While recent research has provided evidence that the emergence of merolimnic insects (species with an aquatic larval stage) provides a considerable energy subsidy to riparian food webs, it has also shown that merolimnic insects may serve as a vector for contaminants. Therefore, riparian food webs may be at risk from either an aquatic-terrestrial transfer of contaminants or from the contaminant-driven reductions of emerging merolimnic insects. The objective of the present study was to develop an integrated stream mesocosms test design capable of identifying these inter-ecosystem boundary effects and to provide a comprehensive approach as a basis for ecotoxicological testing. We chose the widely distributed web-building spider Tetragnatha extensa as a representative species for riparian predators. Trophic aspects of riparian food webs were investigated by stable isotope analysis of carbon (δ(13)C) and nitrogen (δ(15)N). Utilization of stable isotope ratios provided detailed information on the riparian food web structure and the dietary composition of T. extensa. Merolimnic invertebrates (mainly Cloeon spp. and Chironomidae) were found to contribute up to 71 % of T. extensa's diet, demonstrating their importance in riparian food webs in ecotoxicological mesocosm testing. This study provides a conceptual and methodological basis for assessing aquatic insect emergence-related pollutant transfer or effect translation from aquatic to adjacent terrestrial systems. PMID:25586616

  1. The Relative Influence of Aquatic and Terrestrial Processes on Methylmercury Transport in River Basins

    NASA Astrophysics Data System (ADS)

    Burns, D. A.; Bradley, P. M.; Marvin-DiPasquale, M. C.; Aiken, G.; Brigham, M. E.

    2012-12-01

    Conceptual understanding of the mercury (Hg) cycle in river basins is important for the development of improved Hg models that can inform Hg emissions policies, and, therefore, decrease the health risk that stems from widespread high Hg levels found in fresh water fish throughout the US and globally. Distinguishing the relative roles of aquatic and terrestrial ecosystems in Hg transport and transformation is fundamental to improved Hg risk management. The principal zones where Hg is transformed to its methyl form (MeHg), the transport of that MeHg to aquatic ecosystems, and subsequent bioaccumulation in aquatic food webs have been the focus of our investigations for more than 10 years in several small river basins across the US. Our data indicate that most MeHg in these rivers originates at the interface of the terrestrial and aquatic ecosystem in wetlands and riparian areas where anaerobic conditions and abundant organic matter favor methylation. Key factors in addition to methylation potential are those that influence the hydrologic transport of MeHg to adjacent streams and rivers such as hydraulic conductivity in the shallow subsurface and the depth of the water table in riparian areas. The presence and quality of organic matter in wetland soils and in water that moves through wetland areas also plays a pivotal role in MeHg source and transport. We discuss how these factors affect aquatic MeHg concentrations in light of a recently completed investigation of the Hg cycle in river basins in the Adirondack Mountains of New York and Coastal Plain of South Carolina. At each site, MeHg originates primarily in riparian wetland areas and is transported to the streams via shallow groundwater flow. The presence of open water bodies in these basins favors losses of MeHg by any of several processes, though smaller open water bodies may act as net MeHg sources. Ongoing work is building on this conceptualization of the Hg cycle through development of a model based on the

  2. The C.E.B.A. Mini Module on the STS-107 Mission: Data of Ground Experiments and Preliminary Results of the third Spaceflight of an Artificial Aquatic Ecosystem

    NASA Astrophysics Data System (ADS)

    Bluem, V.; Paris, F.; Bungart, S.

    The C.E.B.A.S MINI MODULE is the miniaturized version of an artificial aquatic ecosystem consisting of four subcomponents: a ZOOLOGICAL COMPONENT (aquarium for animals), a BOTANICAL COMPONENT (higher water plant bioreactor), a MICROBIAL COMPONENT (bacteria filter) and an ELECTRONICAL COMPONENT (data acquisition, control unit). It has a total volume of 8.6 liters and contains the ovoviviparous teleost Xiphophorus helleri (swordtail), larvae of the ovuliparous cichlid fish Oreochromis mossambicus, the pulmonate water snail Biomphalaria glabrata, the rootless (non-graivitropic) higher water plant Ceratophyllum demersum (hornweed) and special strains of ammonia oxidizing bacteria. This device was already flown twice successfully in space with the space shuttle missions STS- 89 and STS-90 (NEUROLAB) in 1998. It will fly a third time with the STS-107-mission the launch of which has been repeatedly shifted December 222, April 2001, October 2001) and is now finally scheduled for June 2002. The main focus of scientific interest in the past missions were system performance, reproductive biology (reproductive function of adult females including endocrine system, fertilization, gonadal development in juveniles), vestibular and immunological research in X. helleri, embryology and shell formation in B. glabrata, general morphology and physiology of C. demersum and groth rates of the bacteria. The standard load of the system were 4 adult and 200 neonate X. helleri, 30 adult B. glabrata and 30 g of C. demersum. The evaluation of these experiments showed that all reproductive functions and the immune system of the fishes snails remained undisturbed in space, that the snails developed normally and exhibited no disturbance of shell formation and that the plants showed growth and photosynthesis rates comparable to those on Earth. So, as a logical continuation, the main topics for the STS-107 mission are the remaining important questions in X. helleri biology: puberty, male sexual

  3. The C.E.B.A. Mini Module on the STS-107 Mission: Data of Ground Experiments and Preliminary Results of the third Spaceflight of an Artificial Aquatic Ecosystem

    NASA Astrophysics Data System (ADS)

    Bluem, V.; Paris, F.; Bungart, S.

    The C.E.B.A.S MINI MODULE is the miniaturized version of an artificial aquatic ecosystem consisting of four subcomponents: a ZOOLOGICAL COMPONENT (aquarium for animals), a BOTANICAL COMPONENT (higher water plant bioreactor), a MICROBIAL COMPONENT (bacteria filter) and an ELECTRONICAL COMPONENT (data acquisition, control unit). It has a total volume of 8.6 liters and contains the ovoviviparous teleost Xiphophorus helleri (swordtail), larvae of the ovuliparous cichlid fish Oreochromis mossambicus, the pulmonate water snail Biomphalaria glabrata, the rootless (non-graivitropic) higher water plant Ceratophyllum demersum (hornweed) and special strains of ammonia oxidizing bacteria. This device was already flown twice successfully in space with the space shuttle missions STS- 89 and STS-90 (NEUROLAB) in 1998. It will fly a third time with the STS-107-mission the launch of which has been repeatedly shifted December 222, April 2001, October 2001) and is now finally scheduled for June 2002. The main focus of scientific interest in the past missions were system performance, reproductive biology (reproductive function of adult females including endocrine system, fertilization, gonadal development in juveniles), vestibular and immunological research in X. helleri, embryology and shell formation in B. glabrata, general morphology and physiology of C. demersum and groth rates of the bacteria. The standard load of the system were 4 adult and 200 neonate X. helleri, 30 adult B. glabrata and 30 g of C. demersum. The evaluation of these experiments showed that all reproductive functions and the immune system of the fishes snails remained undisturbed in space, that the snails developed normally and exhibited no disturbance of shell formation and that the plants showed growth and photosynthesis rates comparable to those on Earth. So, as a logical continuation, the main topics for the STS-107 mission are the remaining important questions in X. helleri biology: puberty, male sexual

  4. Aquatic Therapy for Children

    ERIC Educational Resources Information Center

    Kucher, Greta; Moore, Kelsey; Rodia, Rachel; Moser, Christy Szczech

    2015-01-01

    Aquatic therapy has long been highlighted in the literature as a potentially powerful therapeutic intervention. This review will highlight basic definitions of aquatic therapy, review salient research, and identify specific diagnoses that may benefit from aquatic therapy. Online resources, blogs, and books that occupational therapists may find…

  5. Microbial ecology of Antarctic aquatic systems.

    PubMed

    Cavicchioli, Ricardo

    2015-11-01

    The Earth's biosphere is dominated by cold environments, and the cold biosphere is dominated by microorganisms. Microorganisms in cold Southern Ocean waters are recognized for having crucial roles in global biogeochemical cycles, including carbon sequestration, whereas microorganisms in other Antarctic aquatic biomes are not as well understood. In this Review, I consider what has been learned about Antarctic aquatic microbial ecology from 'omic' studies. I assess the factors that shape the biogeography of Antarctic microorganisms, reflect on some of the unusual biogeochemical cycles that they are associated with and discuss the important roles that viruses have in controlling ecosystem function. PMID:26456925

  6. Trace element accumulation in aquatic plants: a literature review

    SciTech Connect

    Ganje, T.J.; Elseewi, A.A.; Page, A.L.

    1988-01-01

    Trace elements in sediments and its overlying waters are important constituents of an aquatic plant ecosystem. This review was undertaken to evaluate trace element accumulation in aquatic plants and ascertain to what extent sediment and its overlying waters play in trace element accumulation by aquatic plant species. Aquatic vascular plants tend to accumulate trace elements in relation to the trace element concentration of the water body and sediment in which they are grown and the extent of exposure to the water body. Trace element composition of bryophytes and algae is also closely related to composition of their aquatic environment. It is increasingly apparent that sediments and overlying waters alter the bioavailability of trace elements to aquatic plants in both natural and artificial water bodies, particularly where industrial and agricultural waters are discharged into waterways.

  7. Beaver herbivory on aquatic plants.

    PubMed

    Parker, John D; Caudill, Christopher C; Hay, Mark E

    2007-04-01

    Herbivores have strong impacts on marine and terrestrial plant communities, but their impact is less well studied in benthic freshwater systems. For example, North American beavers (Castor canadensis) eat both woody and non-woody plants and focus almost exclusively on the latter in summer months, yet their impacts on non-woody plants are generally attributed to ecosystem engineering rather than herbivory. Here, we excluded beavers from areas of two beaver wetlands for over 2 years and demonstrated that beaver herbivory reduced aquatic plant biomass by 60%, plant litter by 75%, and dramatically shifted plant species composition. The perennial forb lizard's tail (Saururus cernuus) comprised less than 5% of plant biomass in areas open to beaver grazing but greater than 50% of plant biomass in beaver exclusions. This shift was likely due to direct herbivory, as beavers preferentially consumed lizard's tail over other plants in a field feeding assay. Beaver herbivory also reduced the abundance of the invasive aquatic plant Myriophyllum aquaticum by nearly 90%, consistent with recent evidence that native generalist herbivores provide biotic resistance against exotic plant invasions. Beaver herbivory also had indirect effects on plant interactions in this community. The palatable plant lizard's tail was 3 times more frequent and 10 times more abundant inside woolgrass (Scirpus cyperinus) tussocks than in spatially paired locations lacking tussocks. When the protective foliage of the woolgrass was removed without exclusion cages, beavers consumed nearly half of the lizard's tail leaves within 2 weeks. In contrast, leaf abundance increased by 73-93% in the treatments retaining woolgrass or protected by a cage. Thus, woolgrass tussocks were as effective as cages at excluding beaver foraging and provided lizard's tail plants an associational refuge from beaver herbivory. These results suggest that beaver herbivory has strong direct and indirect impacts on populations and

  8. Acid Precipitation and the Forest Ecosystem

    ERIC Educational Resources Information Center

    Dochinger, Leon S.; Seliga, Thomas A.

    1975-01-01

    The First International Symposium on Acid Precipitation and the Forest Ecosystem dealt with the potential magnitude of the global effects of acid precipitation on aquatic ecosystems, forest soils, and forest vegetation. The problem is discussed in the light of atmospheric chemistry, transport, and precipitation. (Author/BT)

  9. An endangered oasis of aquatic microbial biodiversity in the Chihuahuan desert.

    PubMed

    Souza, Valeria; Espinosa-Asuar, Laura; Escalante, Ana E; Eguiarte, Luis E; Farmer, Jack; Forney, Larry; Lloret, Lourdes; Rodríguez-Martínez, Juan M; Soberón, Xavier; Dirzo, Rodolfo; Elser, James J

    2006-04-25

    The Cuatro Cienegas basin in the Chihuahuan desert is a system of springs, streams, and pools. These ecosystems support >70 endemic species and abundant living stromatolites and other microbial communities, representing a desert oasis of high biodiversity. Here, we combine data from molecular microbiology and geology to document the microbial biodiversity of this unique environment. Ten water samples from locations within the Cuatro Cienegas basin and two neighboring valleys as well as three samples of wet sediments were analyzed. The phylogeny of prokaryotic populations in the samples was determined by characterizing cultured organisms and by PCR amplification and sequencing of 16S rRNA genes from total community DNA. The composition of microbial communities was also assessed by determining profiles of terminal restriction site polymorphisms of 16S rRNA genes in total community DNA. There were 250 different phylotypes among the 350 cultivated strains. Ninety-eight partial 16S rRNA gene sequences were obtained and classified. The clones represented 38 unique phylotypes from ten major lineages of Bacteria and one of Archaea. Unexpectedly, 50% of the phylotypes were most closely related to marine taxa, even though these environments have not been in contact with the ocean for tens of millions of years. Furthermore, terminal restriction site polymorphism profiles and geological data suggest that the aquatic ecosystems of Cuatro Cienegas are hydrologically interconnected with adjacent valleys recently targeted for agricultural intensification. The findings underscore the conservation value of desert aquatic ecosystems and the urgent need for study and preservation of freshwater microbial communities. PMID:16618921

  10. An endangered oasis of aquatic microbial biodiversity in the Chihuahuan desert

    PubMed Central

    Souza, Valeria; Espinosa-Asuar, Laura; Escalante, Ana E.; Eguiarte, Luis E.; Farmer, Jack; Forney, Larry; Lloret, Lourdes; Rodríguez-Martínez, Juan M.; Soberón, Xavier; Dirzo, Rodolfo; Elser, James J.

    2006-01-01

    The Cuatro Cienegas basin in the Chihuahuan desert is a system of springs, streams, and pools. These ecosystems support >70 endemic species and abundant living stromatolites and other microbial communities, representing a desert oasis of high biodiversity. Here, we combine data from molecular microbiology and geology to document the microbial biodiversity of this unique environment. Ten water samples from locations within the Cuatro Cienegas basin and two neighboring valleys as well as three samples of wet sediments were analyzed. The phylogeny of prokaryotic populations in the samples was determined by characterizing cultured organisms and by PCR amplification and sequencing of 16S rRNA genes from total community DNA. The composition of microbial communities was also assessed by determining profiles of terminal restriction site polymorphisms of 16S rRNA genes in total community DNA. There were 250 different phylotypes among the 350 cultivated strains. Ninety-eight partial 16S rRNA gene sequences were obtained and classified. The clones represented 38 unique phylotypes from ten major lineages of Bacteria and one of Archaea. Unexpectedly, 50% of the phylotypes were most closely related to marine taxa, even though these environments have not been in contact with the ocean for tens of millions of years. Furthermore, terminal restriction site polymorphism profiles and geological data suggest that the aquatic ecosystems of Cuatro Cienegas are hydrologically interconnected with adjacent valleys recently targeted for agricultural intensification. The findings underscore the conservation value of desert aquatic ecosystems and the urgent need for study and preservation of freshwater microbial communities. PMID:16618921

  11. Abundance and community structure of ammonia-oxidizing microorganisms in reservoir sediment and adjacent soils.

    PubMed

    Wang, Xiaoyan; Wang, Cui; Bao, Linlin; Xie, Shuguang

    2014-02-01

    Ammonia oxidation is an important process for global nitrogen cycling. Both ammonia-oxidizing bacteria (AOB) and archaea (AOA) can be the important players in nitrification process. However, their relative contribution to nitrification remains controversial. This study investigated the abundance and community structure of AOA and AOB in sediment of Miyun Reservoir and adjacent soils. Quantitative PCR assays indicated that the highest AOA abundance occurred in unplanted riparian soil, followed by reservoir sediment, reed-planted riparian soil and agricultural soil. The AOB community size in agricultural soil was much larger than that in the other habitats. Large variations in the structures of AOA and AOB were also observed among the different habitats. The abundance of Nitrosospira-like AOB species were detected in the agricultural soil and reservoir sediment. Pearson's correlation analysis showed the AOB diversity had positive significant correlations with pH and total nitrogen, while the AOA diversity might be negatively affected by nitrate nitrogen and ammonia nitrogen. This work could add new insights towards nitrification in aquatic and terrestrial ecosystems. PMID:23949998

  12. Effects of invasive species on plant communities: an example using submersed aquatic plants at the regional level

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Submerged aquatic plants have a key role in maintaining functioning aquatic ecosystems through their effects in the hydrological regime, sedimentation, nutrient cycling and habitats of associated fauna. Modifications of aquatic plant communities, as for example through the introduction of invasive s...

  13. Wildlife and biological resources: Chapter 5 in A synthesis of aquatic science for management of Lakes Mead and Mohave

    USGS Publications Warehouse

    Chandra, Sudeep; Abella, Scott R.; Albrecht, Brandon A.; Barnes, Joseph G.; Engel, E. Cayenne; Goodbred, Steven L.; Holden, Paul B.; Kegerries, Ron B.; Jaeger, Jef R.; Orsak, Erik; Rosen, Michael R.; Sjöberg, Jon; Wong, Wai Hing

    2012-01-01

    The creation of Lakes Mead and Mohave drastically changed habitats originally found along their region of the historical Colorado River. While still continuing to provide habitat conditions that support a rich diversity of species within the water, along shorelines, and in adjacent drainage areas, the reservoirs contain organisms that are both native and non-native to the Colorado River drainage (fig. 5-1). The diversity of species within these lakes continues to change with time due to changing habitat conditions, the invasion of non-native species, and extirpations of native species. From the bottom of the food web to the top predators, all organisms within the ecosystem are interconnected in food webs or food-chain networks. As non-native invasive species continue to be introduced into the lakes, alterations to the food web, species competition, and species predation likely will continue to change the ecosystem and populations of native organisms. Following an overview of the food web, this chapter summarizes information on aquatic and aquatic-dependent wildlife at Lakes Mead and Mohave and their relationships within the food web from members of lower trophic levels to the highest: phytoplankton, invertebrates, including zooplankton, and macroinvertebrates; fishes; and birds. The following sections describe the biological diversity, limiting factors, and ecological functions of these groups in Lake Mead, and to a lesser extent, in Lake Mohave.

  14. HUMAN-ECOSYSTEM INTERACTIONS: THE CASE OF MERCURY

    EPA Science Inventory

    Human and ecosystem exposure studies evaluate exposure of sensitive and vulnerable populations. We will discuss how ecosystem exposure modeling studies completed for input into the US Clean Air Mercury Rule (CAMR) to evaluate the response of aquatic ecosystems to changes in mercu...

  15. Mycoloop: chytrids in aquatic food webs

    PubMed Central

    Kagami, Maiko; Miki, Takeshi; Takimoto, Gaku

    2014-01-01

    Parasites are ecologically significant in various ecosystems through their role in shaping food web structure, facilitating energy transfer, and controlling disease. Here in this review, we mainly focus on parasitic chytrids, the dominant parasites in aquatic ecosystems, and explain their roles in aquatic food webs, particularly as prey for zooplankton. Chytrids have a free-living zoosporic stage, during which they actively search for new hosts. Zoospores are excellent food for zooplankton in terms of size, shape, and nutritional quality. In the field, densities of chytrids can be high, ranging from 101 to 109 spores L−1. When large inedible phytoplankton species are infected by chytrids, nutrients within host cells are transferred to zooplankton via the zoospores of parasitic chytrids. This new pathway, the “mycoloop,” may play an important role in shaping aquatic ecosystems, by altering sinking fluxes or determining system stability. The grazing of zoospores by zooplankton may also suppress outbreaks of parasitic chytrids. A food web model demonstrated that the contribution of the mycoloop to zooplankton production increased with nutrient availability and was also dependent on the stability of the system. Further studies with advanced molecular tools are likely to discover greater chytrid diversity and evidence of additional mycoloops in lakes and oceans. PMID:24795703

  16. Mycoloop: chytrids in aquatic food webs.

    PubMed

    Kagami, Maiko; Miki, Takeshi; Takimoto, Gaku

    2014-01-01

    Parasites are ecologically significant in various ecosystems through their role in shaping food web structure, facilitating energy transfer, and controlling disease. Here in this review, we mainly focus on parasitic chytrids, the dominant parasites in aquatic ecosystems, and explain their roles in aquatic food webs, particularly as prey for zooplankton. Chytrids have a free-living zoosporic stage, during which they actively search for new hosts. Zoospores are excellent food for zooplankton in terms of size, shape, and nutritional quality. In the field, densities of chytrids can be high, ranging from 10(1) to 10(9) spores L(-1). When large inedible phytoplankton species are infected by chytrids, nutrients within host cells are transferred to zooplankton via the zoospores of parasitic chytrids. This new pathway, the "mycoloop," may play an important role in shaping aquatic ecosystems, by altering sinking fluxes or determining system stability. The grazing of zoospores by zooplankton may also suppress outbreaks of parasitic chytrids. A food web model demonstrated that the contribution of the mycoloop to zooplankton production increased with nutrient availability and was also dependent on the stability of the system. Further studies with advanced molecular tools are likely to discover greater chytrid diversity and evidence of additional mycoloops in lakes and oceans. PMID:24795703

  17. The Beddington-De Angelis and the HTII product response functions: Application to polluted ecosystems biodegradation

    NASA Astrophysics Data System (ADS)

    Bulai, Iulia Martina; Venturino, Ezio

    2016-06-01

    In this paper we consider an aquatic ecosystem consisting of bacteria, organic pollutants and dissolved oxygen. By formulating two suitable mathematical models for their interactions, we investigate the sustainability in time of this ecosystem.

  18. Characterization factors for thermal pollution in freshwater aquatic environments.

    PubMed

    Verones, Francesca; Hanafiah, Marlia Mohd; Pfister, Stephan; Huijbregts, Mark A J; Pelletier, Gregory J; Koehler, Annette

    2010-12-15

    To date the impact of thermal emissions has not been addressed in life cycle assessment despite the narrow thermal tolerance of most aquatic species. A method to derive characterization factors for the impact of cooling water discharges on aquatic ecosystems was developed which uses space and time explicit integration of fate and effects of water temperature changes. The fate factor is calculated with a 1-dimensional steady-state model and reflects the residence time of heat emissions in the river. The effect factor specifies the loss of species diversity per unit of temperature increase and is based on a species sensitivity distribution of temperature tolerance intervals for various aquatic species. As an example, time explicit characterization factors were calculated for the cooling water discharge of a nuclear power plant in Switzerland, quantifying the impact on aquatic ecosystems of the rivers Aare and Rhine. The relative importance of the impact of these cooling water discharges was compared with other impacts in life cycle assessment. We found that thermal emissions are relevant for aquatic ecosystems compared to other stressors, such as chemicals and nutrients. For the case of nuclear electricity investigated, thermal emissions contribute between 3% and over 90% to Ecosystem Quality damage. PMID:21069953

  19. Aquatic fungi: targeting the forgotten in microbial ecology.

    PubMed

    Grossart, Hans-Peter; Rojas-Jimenez, Keilor

    2016-06-01

    Fungi constitute important and conspicuous components of aquatic microbial communities, but their diversity and functional roles remain poorly characterized. New methods and conceptual frameworks are required to accurately describe their ecological roles, involvement in global cycling processes, and utility for human activities, considering both cultivation-independent techniques as well as experiments in laboratory and in natural ecosystems. Here we highlight recent developments and extant knowledge gaps in aquatic mycology, and provide a conceptual model to expose the importance of fungi in aquatic food webs and related biogeochemical processes. PMID:27078576

  20. Aquatic Activities for Youth.

    ERIC Educational Resources Information Center

    Greene, H. David; And Others

    Designed to meet the diverse educational needs of youth groups, this aquatic program consists of eight individual lesson units, each devoted to one aspect of the aquatic world. Unit topics include: fish aquariums; raising earthworms; simulation of coastal planning; entomology and water; rope; calculating stream flow; saltwater aquariums; and fish…

  1. Implications of aquatic animal health for human health.

    PubMed Central

    Dawe, C J

    1990-01-01

    Human health and aquatic animal health are organically related at three distinct interfaces. Aquatic animals serve as important contributors to the nutritional protein, lipid, and vitamin requirements of humans; as carriers and transmitters of many infectious and parasitic diseases to which humans are susceptible; and as indicators of toxic and carcinogenic substances that they can convey, in some part, from aquatic environments to man and other terrestrial animals. Transcending these relationships, but less visible and definable to many, is the role that aquatic animals play in the sustenance of our integrated planetary ecosystem. Up to the present, this ecosystem has been compatible with mankind's occupation of a niche within it at high but ultimately limited population levels. In the past century we have become clearly aware that human activities, particularly over-harvesting of aquatic animals together with chemical degradation of their habitats, can quite rapidly lead to perturbances that drastically shift aquatic ecosystems toward conditions of low productivity and impaired function as one of earth's vital organs. The negative values of aquatic animals as disease vectors are far outweighed by their positive values as nutritional sources and as sustainers of a relatively stable equilibrium in the global ecosystem. In the immediate future we can expect to see increased and improved monitoring of aquatic habitats to determine the extent to which aquatic animals cycle anthropogenic toxic and carcinogenic chemicals back to human consumers. In the long term, methods are particularly needed to assess the effects of these pollutants on reproductive success in aquatic communities and in human communities as well. As inputs of habitat-degrading substances change in quality and quantity, it becomes increasingly urgent to evaluate the consequences in advance, not in retrospect. A new, more realistic and comprehensive philosophy regarding aquatic environmental

  2. Public Lakes, Private Lakeshore: Modeling Protection of Native Aquatic Plants

    NASA Astrophysics Data System (ADS)

    Schroeder, Susan A.; Fulton, David C.

    2013-07-01

    Protection of native aquatic plants is an important proenvironmental behavior, because plant loss coupled with nutrient loading can produce changes in lake ecosystems. Removal of aquatic plants by lakeshore property owners is a diffuse behavior that may lead to cumulative impacts on lake ecosystems. This class of behavior is challenging to manage because collective impacts are not obvious to the actors. This paper distinguishes positive and negative beliefs about aquatic plants, in models derived from norm activation theory (Schwartz, Adv Exp Soc Psychol 10:221-279, 1977) and the theory of reasoned action (Fishbein and Ajzen, Belief, attitude, intention, and behavior: an introduction to theory and research, Addison-Wesley, Boston 1975), to examine protection of native aquatic plants by Minnesota lakeshore property owners. We clarify how positive and negative evaluations of native aquatic plants affect protection or removal of these plants. Results are based on a mail survey ( n = 3,115). Results suggest that positive evaluations of aquatic plants (i.e., as valuable to lake ecology) may not connect with the global attitudes and behavioral intentions that direct plant protection or removal. Lakeshore property owners' behavior related to aquatic plants may be driven more by tangible personal benefits derived from accessible, carefully managed lakeshore than intentional action taken to sustain lake ecosystems. The limited connection of positive evaluations of aquatic plants to global attitudes and behavioral intentions may reflect either lack of knowledge of what actions are needed to protect lake health and/or unwillingness to lose perceived benefits derived from lakeshore property.

  3. Public lakes, private lakeshore: modeling protection of native aquatic plants.

    PubMed

    Schroeder, Susan A; Fulton, David C

    2013-07-01

    Protection of native aquatic plants is an important proenvironmental behavior, because plant loss coupled with nutrient loading can produce changes in lake ecosystems. Removal of aquatic plants by lakeshore property owners is a diffuse behavior that may lead to cumulative impacts on lake ecosystems. This class of behavior is challenging to manage because collective impacts are not obvious to the actors. This paper distinguishes positive and negative beliefs about aquatic plants, in models derived from norm activation theory (Schwartz, Adv Exp Soc Psychol 10:221-279, 1977) and the theory of reasoned action (Fishbein and Ajzen, Belief, attitude, intention, and behavior: an introduction to theory and research, Addison-Wesley, Boston 1975), to examine protection of native aquatic plants by Minnesota lakeshore property owners. We clarify how positive and negative evaluations of native aquatic plants affect protection or removal of these plants. Results are based on a mail survey (n = 3,115). Results suggest that positive evaluations of aquatic plants (i.e., as valuable to lake ecology) may not connect with the global attitudes and behavioral intentions that direct plant protection or removal. Lakeshore property owners' behavior related to aquatic plants may be driven more by tangible personal benefits derived from accessible, carefully managed lakeshore than intentional action taken to sustain lake ecosystems. The limited connection of positive evaluations of aquatic plants to global attitudes and behavioral intentions may reflect either lack of knowledge of what actions are needed to protect lake health and/or unwillingness to lose perceived benefits derived from lakeshore property. PMID:23609308

  4. METHODOLOGY FOR THE EVALUATION OF CUMULATIVE EPISODIC EXPOSURE TO CHEMICAL STRESSORS IN AQUATIC RISK ASSESSMENT.

    EPA Science Inventory

    An ecological risk assessment method was developed to evaluate the magnitude, duration, and episodic nature of chemical stressors on aquatic communities. The percent of an ecosystem's species at risk from a designated chemical exposure scenario is generated. In effects assessment...

  5. The distance that contaminated aquatic subsidies extend into lake riparian zones

    EPA Science Inventory

    Consumption of emergent aquatic insects by terrestrial invertebrates is a poorly resolved, but potentially important, mechanism of contaminant flux across ecosystem borders leading to contaminant exposure in terrestrial invertevores. We characterized the spatial extent and magnit...

  6. GROUP REPORT: PHYSIOLOGICAL AND ECOLOGICAL EFFECTS OF ACIDIFICATION ON AQUATIC BIOTA

    EPA Science Inventory

    Acidification affects all components of biological communities in lakes and streams: microbes, algae, macrophytes, invertebrates, fish, amphibians, and other vertebrates that rely on aquatic ecosystems for habitat or food. echanisms of effect are both direct (toxic responses to c...

  7. Land-use proxies for aquatic species invasions in the Laurentian Great Lakes

    EPA Science Inventory

    Aquatic invasive species adversely impact ecosystems, human health, and the economy of the Laurentian Great Lakes region. Targeted preventative and eradication efforts in response to early detection of invasive species can be both cost advantageous and effective. But where should...

  8. Predicting submerged aquatic vegetation cover and occurrence in a Lake Superior estuary

    EPA Science Inventory

    Submerged aquatic vegetation (SAV) provides the biophysical basis for multiple ecosystem services in Great Lakes estuaries. Understanding sources of variation in SAV is necessary for sustainable management of SAV habitat. From data collected in 2011 using hydroacoustic survey met...

  9. Linking Changes in Management and Riparian Physical Functionality to Water Quality and Aquatic Habitat

    EPA Science Inventory

    Wildlife and aquatic habitats are dependent on the development of riparian area management strategies. Land management strategies consider certain basic ecological and economic relationships. These relationships are functions of riparian and te rrestrial ecosystems, which include...

  10. Using aquatic vegetation to remediate nitrate, ammonium, and soluble reactive phosphorus in simulated runoff

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Within the agriculturally-intensive Mississippi River Basin of the United States, significant conservation efforts have focused on management practices that reduce nutrient runoff into receiving aquatic ecosystems. Only a small fraction of those efforts have focused on phytoremediation techniques. ...

  11. A Computer Simulation of the Trophic Dynamics of an Aquatic System.

    ERIC Educational Resources Information Center

    Bowker, D. W.; Randerson, P. F.

    1989-01-01

    Described is a computer program, AQUASIM, which simulates interaction between environmental factors, phytoplankton, zooplankton, and fish in an aquatic ecosystem. The conceptual flow, equations, variables, rate processes, and parameter manipulations are discussed. (CW)

  12. HARMFUL ALGAL BLOOMS AS INDICATORS OF ECOSYSTEM CONDITION

    EPA Science Inventory

    There are approximately 40 species of microalgae inhabiting coastal waters in the Gulf of Mexico that produce or potentially can produce biotoxins that negatively impact aquatic ecosystems, human health, and local economics. While nutrient enrichment and reduced water quality may...

  13. In-stream net ecosystem metabolism differences across a glacial coverage gradient in southeast Alaska

    NASA Astrophysics Data System (ADS)

    Nassry, M. Q.; Hood, E. W.; Scott, D.; Vermilyea, A.

    2010-12-01

    As glacier ice gives way to successional vegetation, streams located in glacier-containing watersheds receive decreased contributions from glacial meltwater and increased contributions from terrestrial landscapes. Aquatic communities in streams receiving varying amounts of glacial meltwater were compared during this research to determine the effect of changing inputs of glacial meltwater on net ecosystem metabolism (NEM). In particular, we tested the hypothesis that decreased inputs of glacier meltwater will result in increased NEM in coastal streams in southeast Alaska. Dissolved oxygen and temperature measurements were collected at 5-minute increments using multi-sensor probes for 48 hours at four study streams. Additionally, discharge and velocity measurements were collected along with surface water samples during each of three replicate study periods at all four streams. Single station diel curves of in-stream oxygen concentration and water temperature changes were generated to establish community respiration (CR24) and gross primary production (GPP) values. The study watersheds, all of which are adjacent to the Juneau Icefield, range in area from 23-158 km2 and in watershed glacial coverage from 0-40%. This research will provide new insights into how changes in runoff from rapidly thinning and receding glaciers in southeast Alaska will affect aquatic community metabolism in downstream ecosystems. Ultimately, this will provide a better understanding of the changing in-stream processing capabilities in watersheds affected by land cover changes resulting from glacial recession.

  14. Assessing risks to ecosystem quality

    SciTech Connect

    Barnthouse, L.W.

    1995-12-31

    Ecosystems are not organisms. Because ecosystems do not reproduce, grow old or sick, and die, the term ecosystem health is somewhat misleading and perhaps should not be used. A more useful concept is ``ecosystem quality,`` which denotes a set of desirable ecosystem characteristics defined in terms of species composition, productivity, size/condition of specific populations, or other measurable properties. The desired quality of an ecosystem may be pristine, as in a nature preserve, or highly altered by man, as in a managed forest or navigational waterway. ``Sustainable development`` implies that human activities that influence ecosystem quality should be managed so that high-quality ecosystems are maintained for future generations. In sustainability-based environmental management, the focus is on maintaining or improving ecosystem quality, not on restricting discharges or requiring particular waste treatment technologies. This approach requires management of chemical impacts to be integrated with management of other sources of stress such as erosion, eutrophication, and direct human exploitation. Environmental scientists must (1) work with decision makers and the public to define ecosystem quality goals, (2) develop corresponding measures of ecosystem quality, (3) diagnose causes for departures from desired states, and (4) recommend appropriate restoration actions, if necessary. Environmental toxicology and chemical risk assessment are necessary for implementing the above framework, but they are clearly not sufficient. This paper reviews the state-of-the science relevant to sustaining the quality of aquatic ecosystems. Using the specific example of a reservoir in eastern Tennessee, the paper attempts to define roles for ecotoxicology and risk assessment in each step of the management process.

  15. Ecosystem Jenga!

    ERIC Educational Resources Information Center

    Umphlett, Natalie; Brosius, Tierney; Laungani, Ramesh; Rousseau, Joe; Leslie-Pelecky, Diandra L.

    2009-01-01

    To give students a tangible model of an ecosystem and have them experience what could happen if a component of that ecosystem were removed; the authors developed a hands-on, inquiry-based activity that visually demonstrates the concept of a delicately balanced ecosystem through a modification of the popular game Jenga. This activity can be…

  16. Ecosystem Journalism

    ERIC Educational Resources Information Center

    Robertson, Amy; Mahlin, Kathryn

    2005-01-01

    If the organisms in a prairie ecosystem created a newspaper, what would it look like? What important news topics of the ecosystem would the organisms want to discuss? Imaginative and enthusiastic third-grade students were busy pondering these questions as they tried their hands at "ecosystem journalism." The class had recently completed a study of…

  17. EVALUATION OF BIOLOGICAL ACTIVITY OF VITELLOGENIN EXPRESSION IN DIFFERENT AQUATIC MESOCOSM TROPIC LEVELS

    EPA Science Inventory

    Aquatic mesocosms were dosed with an environmentally relevant concentration of 17-a-ethinyl estradiol (EE2) to study the significance of trophic status (N, P levels) on the attenuation and bioavailability of synthetic estrogens in aquatic ecosystems. Estrogenic activity was asse...

  18. Respiration in Aquatic Insects.

    ERIC Educational Resources Information Center

    MacFarland, John

    1985-01-01

    This article: (1) explains the respiratory patterns of several freshwater insects; (2) describes the differences and mechanisms of spiracular cutaneous, and gill respiration; and (3) discusses behavioral aspects of selected aquatic insects. (ML)

  19. Developing a Collegiate Aquatics Program.