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Sample records for selected freshwater biota

  1. Toxicities of selected substances to freshwater biota

    Energy Technology Data Exchange (ETDEWEB)

    Hohreiter, D.W.

    1980-05-01

    The amount of data available concerning the toxicity of various substances to freshwater biota is so large that it is difficult to use in a practical situation, such as environmental impact assessment. In this document, summary tables are presented showing acute and/or chronic toxicity of selected substances for various groups of aquatic biota. Each entry is referenced to its original source so that details concerning experimental conditions may be consulted. In addition, general information concerning factors modifying toxicity, synergisms, evidence of bioaccumulation, and water quality standards and criteria for the selected substances is given. The final table is a general toxicity table designed to provide an easily accessible and general indication of toxicity of selected substances in aquatic systems.

  2. Transfers to freshwater biota

    International Nuclear Information System (INIS)

    It remains important to monitor the fate of radionuclides, particularly in environmental compartments that comprise human pathways. Therefore, an extensive literature survey has been conducted to compile available data on the transfer of radionuclides and their analogues to edible freshwater biota. Focus was placed on compilation of steady state transfer parameters for two freshwater pathways, including water-to-biota and sediment-to-biota. In general, although in many cases, extensive data were available for fishes and invertebrates, relatively fewer data were available for freshwater primary producers, amphibians and reptiles. To fill in these gaps, data were also compiled on the internal partitioning of elements in the body with respect to tissue masses, which could be used to estimate radionuclide concentrations between compartments in the body. (author)

  3. Selected chlorobornanes, polychlorinated naphthalenes and brominated flame retardants in Bjornoya (Bear Island) freshwater biota

    International Nuclear Information System (INIS)

    Levels of selected sparsely investigated persistent organic pollutants (POPs) have been measured in organisms from two Arctic lakes on Bjornoya (Bear Island). Elevated levels of chlorobornanes (CHBs) (up to 46.7 ng/g wet weight=ww), polybrominated diphenyl ethers (PBDEs) (up to 27.2 ng/g ww), polybrominated biphenyls (PBBs) (up to 1.1 ng/g ww) and polychlorinated naphthalenes (PCNs, only 4 congeners) (up to 62.7 pg/g ww), were measured in biota from Lake Ellasjoen. In Lake Oyangen, located only 5 km north of Ellasjoen, levels of these contaminants were significantly lower. δ15N-values were 7-10%o higher in organisms from Ellasjoen as compared to Oyangen. This is attributed to biological inputs related to seabird activities. The present study illustrates that contaminants such as CHBs, brominated flame retardants and PCNs accumulate in the Ellasjoen food web in a manner similar to PCBs and conventional organochlorine pesticides. Transport mechanisms that control PCB and DDT distributions, i.e. atmospheric long-range transport and biotransport by seabirds, are also relevant for the contaminants investigated in the present study. - Elevate levels of chlorobornanes, polychlorinated naphthalenes and brominated flame retardants have been measured in biota from a Norwegian Arctic lake

  4. Selected chlorobornanes, polychlorinated naphthalenes and brominated flame retardants in Bjornoya (Bear Island) freshwater biota

    Energy Technology Data Exchange (ETDEWEB)

    Evenset, Anita [Akvaplan-niva, Polar Environmental Centre, N-9296 Tromso (Norway)]. E-mail: ae@akvaplan.niva.no; Christensen, Guttorm N. [Akvaplan-niva, Polar Environmental Centre, N-9296 Tromso (Norway); Kallenborn, Roland [Norwegian Institute for Air Research, P.O. Box 100, N-2027 Kjeller (Norway)

    2005-08-15

    Levels of selected sparsely investigated persistent organic pollutants (POPs) have been measured in organisms from two Arctic lakes on Bjornoya (Bear Island). Elevated levels of chlorobornanes (CHBs) (up to 46.7 ng/g wet weight=ww), polybrominated diphenyl ethers (PBDEs) (up to 27.2 ng/g ww), polybrominated biphenyls (PBBs) (up to 1.1 ng/g ww) and polychlorinated naphthalenes (PCNs, only 4 congeners) (up to 62.7 pg/g ww), were measured in biota from Lake Ellasjoen. In Lake Oyangen, located only 5 km north of Ellasjoen, levels of these contaminants were significantly lower. {delta}{sup 15}N-values were 7-10%o higher in organisms from Ellasjoen as compared to Oyangen. This is attributed to biological inputs related to seabird activities. The present study illustrates that contaminants such as CHBs, brominated flame retardants and PCNs accumulate in the Ellasjoen food web in a manner similar to PCBs and conventional organochlorine pesticides. Transport mechanisms that control PCB and DDT distributions, i.e. atmospheric long-range transport and biotransport by seabirds, are also relevant for the contaminants investigated in the present study. - Elevate levels of chlorobornanes, polychlorinated naphthalenes and brominated flame retardants have been measured in biota from a Norwegian Arctic lake.

  5. Selected chlorobornanes, polychlorinated naphthalenes and brominated flame retardants in Bjørnøya (Bear Island) freshwater biota.

    Science.gov (United States)

    Evenset, Anita; Christensen, Guttorm N; Kallenborn, Roland

    2005-08-01

    Levels of selected sparsely investigated persistent organic pollutants (POPs) have been measured in organisms from two Arctic lakes on Bjørnøya (Bear Island). Elevated levels of chlorobornanes (CHBs) (up to 46.7 ng/g wet weight=ww), polybrominated diphenyl ethers (PBDEs) (up to 27.2 ng/g ww), polybrominated biphenyls (PBBs) (up to 1.1 ng/g ww) and polychlorinated naphthalenes (PCNs, only 4 congeners) (up to 62.7 pg/g ww), were measured in biota from Lake Ellasjøen. In Lake Øyangen, located only 5 km north of Ellasjøen, levels of these contaminants were significantly lower. delta(15)N-values were 7-10 per thousand higher in organisms from Ellasjøen as compared to Øyangen. This is attributed to biological inputs related to seabird activities. The present study illustrates that contaminants such as CHBs, brominated flame retardants and PCNs accumulate in the Ellasjøen food web in a manner similar to PCBs and conventional organochlorine pesticides. Transport mechanisms that control PCB and DDT distributions, i.e. atmospheric long-range transport and biotransport by seabirds, are also relevant for the contaminants investigated in the present study. PMID:15862396

  6. Bioaccumulation factors for radionuclides in freshwater biota

    International Nuclear Information System (INIS)

    This report analyzes over 200 carefully selected papers to provide concise data sets and methodology for estimation of bioaccumulation factors for tritium and isotopes of strontium, cesium, iodine, manganese, and cobalt in major biotic components of freshwater environments. Bioaccumulation factors of different tissues are distinguished where significant differences occur. Since conditions in the laboratory are often unnatural in terms of chemical and ecological relationships, this review was restricted as far as possible to bioaccumulation factors determined for natural systems. Because bioaccumulation factors were not available for some shorter-lived radionuclides, a methodology for converting bioaccumulation factors of stable isotopes to those of shorter-lived radionuclides was derived and utilized. The bioaccumulation factor for a radionuclide in a given organism or tissue may exhibit wide variations among bodies of water that are related to differences in ambient concentrations of stable-element and carrier-element analogues. To account for these variations, simple models are presented that relate bioaccumulation factors to stable-element and carrier-element concentrations in water. The effects of physicochemical form and other factors in causing deviations from these models are discussed. Bioaccumulation factor data are examined in the context of these models, and bioaccumulation factor relations for the selected radionuclides are presented

  7. Concordant biogeographic patterns among multiple taxonomic groups in the Mexican freshwater biota.

    Science.gov (United States)

    Quiroz-Martínez, Benjamín; Alvarez, Fernando; Espinosa, Héctor; Salgado-Maldonado, Guillermo

    2014-01-01

    In this paper we analyse the degree of concordance in species richness and taxonomic distinctness (diversity) patterns among different freshwater taxonomic groups in order to test three long held patterns described in Mexican freshwater biogeography: 1. The aquatic biota of Mexico includes two distinct faunas, a rich Neotropical component in the south and a south-eastern region and a less rich Nearctic component towards central and northern latitudes of the country. 2. A hotspot of species richness and diversity has been recorded in the Usumacinta, including the Yucatan Peninsula. 3. The presence of two distinct biotas in Mexico, an eastern one distributed along the Gulf of Mexico slope, and a western one associated to the Pacific versant. We use species richness and taxonomic distinctness to explore patterns of diversity and how these patterns change between zoogeographical regions. This paper points out a clear separation between Neotropical and Nearctic drainage basins but also between eastern (Gulf of Mexico) and western (Pacific) drainage basins. Present data gives additional empirical support from freshwater biota for three long held beliefs regarding distributional patterns of the Mexican biota. The neotropical basins of Mexico are generally host to a richest and more diversified fauna, that includes more families, genera and species, compared to the less rich and less diverse fauna in the nearctic basins. PMID:25136979

  8. Concordant biogeographic patterns among multiple taxonomic groups in the Mexican freshwater biota.

    Directory of Open Access Journals (Sweden)

    Benjamín Quiroz-Martínez

    Full Text Available In this paper we analyse the degree of concordance in species richness and taxonomic distinctness (diversity patterns among different freshwater taxonomic groups in order to test three long held patterns described in Mexican freshwater biogeography: 1. The aquatic biota of Mexico includes two distinct faunas, a rich Neotropical component in the south and a south-eastern region and a less rich Nearctic component towards central and northern latitudes of the country. 2. A hotspot of species richness and diversity has been recorded in the Usumacinta, including the Yucatan Peninsula. 3. The presence of two distinct biotas in Mexico, an eastern one distributed along the Gulf of Mexico slope, and a western one associated to the Pacific versant. We use species richness and taxonomic distinctness to explore patterns of diversity and how these patterns change between zoogeographical regions. This paper points out a clear separation between Neotropical and Nearctic drainage basins but also between eastern (Gulf of Mexico and western (Pacific drainage basins. Present data gives additional empirical support from freshwater biota for three long held beliefs regarding distributional patterns of the Mexican biota. The neotropical basins of Mexico are generally host to a richest and more diversified fauna, that includes more families, genera and species, compared to the less rich and less diverse fauna in the nearctic basins.

  9. Hardness corrections for copper are inappropriate for protecting sensitive freshwater biota.

    Science.gov (United States)

    Markich, S J; Batley, G E; Stauber, J L; Rogers, N J; Apte, S C; Hyne, R V; Bowles, K C; Wilde, K L; Creighton, N M

    2005-06-01

    Toxicity testing using a freshwater alga (Chlorella sp.), a bacterium (Erwinnia sp.) and a cladoceran (Ceriodaphnia cf. dubia) exposed to copper in synthetic and natural freshwaters of varying hardness (44-375 mg CaCO3/l), with constant alkalinity, pH and dissolved organic carbon concentration, demonstrated negligible hardness effects in the pH range 6.1-7.8. Therefore, the use of a generic hardness-correction algorithm, developed as part of national water quality guidelines for protecting freshwater biota, is not recommended for assessing the toxicity of copper to these, and other, sensitive freshwater species. Use of the algorithm for these sensitive species will be underprotective because the calculated concentrations of copper in water that cause a toxic effect will be higher.

  10. TOXIC EFFECT OF PESTICIDES ON THE BIOTA OF FRESHWATER RESERVOIRS OF UKRAINE (A REVIEW)

    OpenAIRE

    N. Kolesnyk

    2015-01-01

    Purpose. To analyze scientific sources on the studies of toxic and lethal concentrations of pesticides on phytoplankton, zooplankton, zoobenthos and fish in current conditions of Ukraine. Findings. A review of works of a variety of scientists showed that pesticides with different chemical origins have disastrous effects on everyone without the exception of freshwater biota organisms. The article highlights the peculiarities of the toxic effects of pesticides of major chemical groups, whic...

  11. TOXIC EFFECT OF PESTICIDES ON THE BIOTA OF FRESHWATER RESERVOIRS OF UKRAINE (A REVIEW

    Directory of Open Access Journals (Sweden)

    N. Kolesnyk

    2015-12-01

    Full Text Available Purpose. To analyze scientific sources on the studies of toxic and lethal concentrations of pesticides on phytoplankton, zooplankton, zoobenthos and fish in current conditions of Ukraine. Findings. A review of works of a variety of scientists showed that pesticides with different chemical origins have disastrous effects on everyone without the exception of freshwater biota organisms. The article highlights the peculiarities of the toxic effects of pesticides of major chemical groups, which are used or stored in Ukraine. Their toxic and lethal concentrations for the major species of phytoplankton, zooplankton, zoobenthos and ichthyofauna reservoirs are considered. The data on basic features of behavioral reactions of aquatic organisms on poisoning by pesticides are provided. The basic structural and systemic diosrders of homeostasis of the organisms of aquatic biota are described. The effect of pesticides on phytoplankton needs further research, however, is was found that they have common feature as the disturbace of photosynthesis process and accumulation. In turn, this provoques kills in water bodies and poisoning of phytoplanctivorous fish. Zooplanktonic organisms are highly sensitive to pesticides; hence they can be used as an indicator of the state of fresh water. It was found that, pesticides depending on their concentration have different toxic effects on zooplankton organisms. The effect of pesticides on benthic organisms was little investigated. It is known that benthic communities respond to the presence of pesticide by changes in species composition, number of species, abundance and biomass of benthos in general and individual taxonomic groups of benthic invertebrates. The toxicity of pesticides for fish depends on their chemical nature, the form of the preparation, dose, fish species and age, water temperature and the content of oxygen and salts. In particular, juvenile fish are much more sensitive to the chemicals, and an increase in

  12. Methodology for Estimating Radiation Dose Rates to Freshwater Biota Exposed to Radionuclides in the Environment

    Energy Technology Data Exchange (ETDEWEB)

    Blaylock, B.G.

    1993-01-01

    The purpose of this report is to present a methodology for evaluating the potential for aquatic biota to incur effects from exposure to chronic low-level radiation in the environment. Aquatic organisms inhabiting an environment contaminated with radioactivity receive external radiation from radionuclides in water, sediment, and from other biota such as vegetation. Aquatic organisms receive internal radiation from radionuclides ingested via food and water and, in some cases, from radionuclides absorbed through the skin and respiratory organs. Dose rate equations, which have been developed previously, are presented for estimating the radiation dose rate to representative aquatic organisms from alpha, beta, and gamma irradiation from external and internal sources. Tables containing parameter values for calculating radiation doses from selected alpha, beta, and gamma emitters are presented in the appendix to facilitate dose rate calculations. The risk of detrimental effects to aquatic biota from radiation exposure is evaluated by comparing the calculated radiation dose rate to biota to the U.S. Department of Energy's (DOE's) recommended dose rate limit of 0.4 mGy h{sup -1} (1 rad d{sup -1}). A dose rate no greater than 0.4 mGy h{sup -1} to the most sensitive organisms should ensure the protection of populations of aquatic organisms. DOE's recommended dose rate is based on a number of published reviews on the effects of radiation on aquatic organisms that are summarized in the National Council on Radiation Protection and Measurements Report No. 109 (NCRP 1991). The literature identifies the developing eggs and young of some species of teleost fish as the most radiosensitive organisms. DOE recommends that if the results of radiological models or dosimetric measurements indicate that a radiation dose rate of 0.1 mGy h{sup -1} will be exceeded, then a more detailed evaluation of the potential ecological consequences of radiation exposure to endemic

  13. Methodology for estimating radiation dose rates to freshwater biota exposed to radionuclides in the environment

    Energy Technology Data Exchange (ETDEWEB)

    Blaylock, B.G.; Frank, M.L.; O`Neal, B.R.

    1993-08-01

    The purpose of this report is to present a methodology for evaluating the potential for aquatic biota to incur effects from exposure to chronic low-level radiation in the environment. Aquatic organisms inhabiting an environment contaminated with radioactivity receive external radiation from radionuclides in water, sediment, and from other biota such as vegetation. Aquatic organisms receive internal radiation from radionuclides ingested via food and water and, in some cases, from radionuclides absorbed through the skin and respiratory organs. Dose rate equations, which have been developed previously, are presented for estimating the radiation dose rate to representative aquatic organisms from alpha, beta, and gamma irradiation from external and internal sources. Tables containing parameter values for calculating radiation doses from selected alpha, beta, and gamma emitters are presented in the appendix to facilitate dose rate calculations. The risk of detrimental effects to aquatic biota from radiation exposure is evaluated by comparing the calculated radiation dose rate to biota to the U.S. Department of Energy`s (DOE`s) recommended dose rate limit of 0.4 mGy h{sup {minus}1} (1 rad d{sup {minus}1}). A dose rate no greater than 0.4 mGy h{sup {minus}1} to the most sensitive organisms should ensure the protection of populations of aquatic organisms. DOE`s recommended dose rate is based on a number of published reviews on the effects of radiation on aquatic organisms that are summarized in the National Council on Radiation Protection and Measurements Report No. 109 (NCRP 1991). DOE recommends that if the results of radiological models or dosimetric measurements indicate that a radiation dose rate of 0. 1 mGy h{sup {minus}1} will be exceeded, then a more detailed evaluation of the potential ecological consequences of radiation exposure to endemic populations should be conducted.

  14. Linking catchment and in-stream processes for an integrated simulation of freshwater biota

    Science.gov (United States)

    Kiesel, Jens; Hering, Daniel; Jähnig, Sonja; Schmalz, Britta; Fohrer, Nicola

    2015-04-01

    Natural catchments, streams and aquatic diversity are globally degraded due to the impacts of industrial and urban development, as well as the intensification of agriculture. Degradation occurres at different spatial scales and rehabilitation measures are required in both streams and catchments, to improve conditions for the aquatic biota. Models, applied for planning restoration measures, are mostly targeting individual components of the complex chain linking the abiotic and biotic environment; e.g., models might be used just for predicting hydrological or hydraulic variables. Hereby, the cause-effect chain is compromised, which links drivers, pressures, state and impacts of the riverine system. We describe the design of an integrated, GIS-based model system considering the cause-effect chain from the catchment to the stream and aquatic biota. The models require data on climatic and physical catchment properties, and on the geometry and structure of the streams. This enables the assessment of the impact of global change as well as of more regional and local changes on the stream ecosystem on different scales. The approach is based on the Driver-Pressure-State-Impact-(Response) concept and includes the linkage of one ecohydrologic, two hydraulic and two habitat models: The ecohydrologic model SWAT was used for depicting the discharge regime and ero-sion processes controlled by land use and climate on the catchment scale. The discharge and sediment time series resulting from the hydrologic modelling were used for hydraulic simulations on the reach scale. Water depth, flow velocity, substrate changes and sediment transport were simulated in variable resolutions with the hydraulic models HEC-RAS one-dimensionally and with AdH two-dimensionally. Combined with structural river mapping, the temporally and spatially dynamic results of the hydraulic models were used for describing macroinvertebrate habitats. Two independent simulations were carried out: First, the

  15. Toxicity of 35 trace elements in coal to freshwater biota: a data base with automated retrieval capabilities. [313 references

    Energy Technology Data Exchange (ETDEWEB)

    Cushman, R. M.; Hildebrand, S. G.; Strand, R. H.; Anderson, R. M.

    1977-06-01

    Data are tabulated on the toxicity to freshwater biota of 35 trace elements with the potential for release to the environment from coal conversion effluents. The entire data base is presented on a microfiche appended to the document, in the interest of portability and accessibility. The data were gathered from a variety of research papers, compendia, and reviews. Details of water chemistry and test conditions are presented when available from the documents consulted. The data base may be used by referring directly to the tabulated data as they appear on the microfiche, or, with appropriate computer facilities, by manipulation (sorting, subsetting, or merging) of the data to meet the particular needs of the investigator. The data may be used as they appear in the data base, or the data base may be used to index the cited original papers.

  16. An international model validation exercise on radionuclide transfer and doses to freshwater biota

    International Nuclear Information System (INIS)

    Under the International Atomic Energy Agency (IAEA)'s EMRAS (Environmental Modelling for Radiation Safety) programme, activity concentrations of 60Co, 90Sr, 137Cs and 3H in Perch Lake at Atomic Energy of Canada Limited's Chalk River Laboratories site were predicted, in freshwater primary producers, invertebrates, fishes, herpetofauna and mammals using eleven modelling approaches. Comparison of predicted radionuclide concentrations in the different species types with measured values highlighted a number of areas where additional work and understanding is required to improve the predictions of radionuclide transfer. For some species, the differences could be explained by ecological factors such as trophic level or the influence of stable analogues. Model predictions were relatively poor for mammalian species and herpetofauna compared with measured values, partly due to a lack of relevant data. In addition, concentration ratios are sometimes under-predicted when derived from experiments performed under controlled laboratory conditions representative of conditions in other water bodies.

  17. Freshwater discharges drive high levels of methylmercury in Arctic marine biota.

    Science.gov (United States)

    Schartup, Amina T; Balcom, Prentiss H; Soerensen, Anne L; Gosnell, Kathleen J; Calder, Ryan S D; Mason, Robert P; Sunderland, Elsie M

    2015-09-22

    Elevated levels of neurotoxic methylmercury in Arctic food-webs pose health risks for indigenous populations that consume large quantities of marine mammals and fish. Estuaries provide critical hunting and fishing territory for these populations, and, until recently, benthic sediment was thought to be the main methylmercury source for coastal fish. New hydroelectric developments are being proposed in many northern ecosystems, and the ecological impacts of this industry relative to accelerating climate changes are poorly characterized. Here we evaluate the competing impacts of climate-driven changes in northern ecosystems and reservoir flooding on methylmercury production and bioaccumulation through a case study of a stratified sub-Arctic estuarine fjord in Labrador, Canada. Methylmercury bioaccumulation in zooplankton is higher than in midlatitude ecosystems. Direct measurements and modeling show that currently the largest methylmercury source is production in oxic surface seawater. Water-column methylation is highest in stratified surface waters near the river mouth because of the stimulating effects of terrestrial organic matter on methylating microbes. We attribute enhanced biomagnification in plankton to a thin layer of marine snow widely observed in stratified systems that concentrates microbial methylation and multiple trophic levels of zooplankton in a vertically restricted zone. Large freshwater inputs and the extensive Arctic Ocean continental shelf mean these processes are likely widespread and will be enhanced by future increases in water-column stratification, exacerbating high biological methylmercury concentrations. Soil flooding experiments indicate that near-term changes expected from reservoir creation will increase methylmercury inputs to the estuary by 25-200%, overwhelming climate-driven changes over the next decade.

  18. Non-effect of water hardness on the accumulation and toxicity of copper in a freshwater macrophyte (Ceratophyllum demersum): how useful are hardness-modified copper guidelines for protecting freshwater biota?

    Science.gov (United States)

    Markich, Scott J; King, Angus R; Wilson, Scott P

    2006-12-01

    Several nations have adopted hardness-modified copper (Cu) guidelines for protecting freshwater biota. However, there is a lack of good quality data and mechanistic understanding on the effects of true water hardness (calcium (Ca) and magnesium (Mg)) on the bioavailability and toxicity of Cu to freshwater biota, particularly macrophytes. This study determined the effect of true water hardness (35, 90 and 335 mg CaCO(3)/l, added as Ca and Mg chloride in a 1:1 mole ratio) on the cell surface binding affinity (log K), accumulation and toxicity (96 h growth (biomass and stem length) and photosynthetic pigment inhibition) of Cu in the free-floating submerged macrophyte, Ceratophyllum demersum, in a synthetic freshwater with constant alkalinity (16 mg CaCO(3)/l) and pH (7.0). There were no significant (P>0.05) differences in the cell surface binding affinity, accumulation or toxicity of Cu in C. demersum with a 10-fold increase in water hardness from 35 to 335 mg CaCO(3)/l. The mean 96 h EC(50) values (and 95% confidence intervals) for biomass, the most sensitive endpoint, were 8.4 (7.6-9.2), 8.9 (8.0-9.8) and 9.9 (9.1-10.7) microg/l Cu for 35, 90 and 335 mg CaCO(3)/l, respectively. Speciation calculations indicated only very small (1-6%) differences in the percentage distribution (i.e. bioavailability) of Cu over the hardness range. These collective results indicate no apparent competition between Cu and Ca/Mg for binding sites on the cell surface. Given that the mechanism of Cu uptake (via Cu-specific and Na-linked transporters) is fundamentally different to that of Cd, Ni, Pb and Zn (via Ca transporters), for which other hardness-dependent algorithms have been developed, it is doubtful whether a hardness-modified Cu guideline value will be sufficiently protective of sensitive freshwater biota, such as C. demersum, particularly in medium-hard fresh surface waters with low levels of dissolved organic carbon. The biotic ligand model offers a more flexible and mechanistic

  19. TiO2 nanoparticles for the remediation of eutrophic shallow freshwater systems: Efficiency and impacts on aquatic biota under a microcosm experiment.

    Science.gov (United States)

    Bessa da Silva, Márcia; Abrantes, Nelson; Nogueira, Verónica; Gonçalves, Fernando; Pereira, Ruth

    2016-09-01

    The application of nanomaterials (NMs) in the remediation of eutrophic waters, particularly in the control of internal loading of nutrients, has been started, but limited investigations evaluated the effectiveness of these new treatment approaches and of their potential impacts on species from shallow freshwater lakes. The present work investigated, under a microcosm experiment, the application of a TiO2 nanomaterial both for reducing nutrient (mainly phosphorus and nitrogen forms) desorption and release from sediments (preventive treatment-PT) and for eliminating algal blooms (remediation treatment-RT). Furthermore, we also intended to assess the potential impacts of nano-TiO2 application on key freshwater species. The results showed the effectiveness of nano-TiO2 in controlling the release of phosphates from surface sediment and the subsequent reduction of total phosphorus in the water column. A reduction in total nitrogen was also observed. Such changes in nutrient dynamics contributed to a progressive inhibition of development of algae after the application of the NM in PT microcosms. Concerning the ability of nano-TiO2 to interact with algal cells, this interaction has likely occurred, mainly in RT, enhancing the formation of aggregates and their rapid settlement, thus reducing the algal bloom. Both treatments caused deleterious effects on freshwater species. In PT, Daphnia magna and Lemna minor showed a significant inhibition of several endpoints. Conversely, no inhibitory effect on the growth of Chironomus riparius was recorded. In opposite, C. riparius was the most affected species in RT microcosms. Such difference was probably caused by the formation of larger TiO2-algae aggregates in RT, under a high algal density, that rapidly settled in the sediment, becoming less available for pelagic species. In summary, despite the effectiveness of both treatments in controlling internal nutrient loading and in the mitigating algal bloom episodes, their negative

  20. Polonium-210 and other radionuclides in terrestrial, freshwater and brackish environments Results from the NKS project GAPRAD (Filling knowledge gaps in radiation protection methodologies for non-human biota)

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-01-15

    The background and rationale to filling knowledge gaps in radiation protection methodologies for biota are presented. Concentrations of Po-210 and Pb-210 are reported for biota sampled in Dovrefjell, Norway and selected lake and brackish ecosystems in Finland. Furthermore, details in relation to Po-210 uptake and biokinetics in humans based on experimental studies are recounted. (Author)

  1. Polonium-210 and other radionuclides in terrestrial, freshwater and brackish environments Results from the NKS project GAPRAD (Filling knowledge gaps in radiation protection methodologies for non-human biota)

    International Nuclear Information System (INIS)

    The background and rationale to filling knowledge gaps in radiation protection methodologies for biota are presented. Concentrations of Po-210 and Pb-210 are reported for biota sampled in Dovrefjell, Norway and selected lake and brackish ecosystems in Finland. Furthermore, details in relation to Po-210 uptake and biokinetics in humans based on experimental studies are recounted. (Author)

  2. A review and model assessment of 32P and 33P uptake to biota in freshwater systems

    International Nuclear Information System (INIS)

    Bioaccumulation of key short-lived radionuclides such as 131I and 32,33P may be over-estimated since concentration ratios (CRs) are often based on values for the corresponding stable isotope which do not account for radioactive decay during uptake via the food chain. This study presents estimates for bioaccumulation of radioactive phosphorus which account for both radioactive decay and varying ambient levels of stable P in the environment. Recommended interim CR values for radioactive forms of P as a function of bioavailable stable phosphorus in the water body are presented. Values of CR are presented for three different trophic levels of the aquatic food chain; foodstuffs from all three trophic levels may potentially be consumed by humans. It is concluded that current recommended values of the CR are likely to be significantly over-estimated for radioactive phosphorus in many freshwater systems, particularly lowland rivers. Further research is recommended to field-validate these models and assess their uncertainty. The relative importance of food-chain uptake and direct uptake from water are also assessed from a review of the literature. It can be concluded that food-chain uptake is the dominant accumulation pathway in fish and hence accumulation factors for radioactive phosphorus in farmed fish are likely to be significantly lower than those for wild fish. - Highlights: → A model is developed for radiophosphorus uptake to fish. → Concentration ratios for 32,33P in fish may be over-estimated in freshwater systems. → New recommended values for 32,33P concentration ratios are given. → Farmed fish are likely to have much lower 32,33P uptake than wild fish.

  3. Selecting reliable and robust freshwater macroalgae for biomass applications.

    Directory of Open Access Journals (Sweden)

    Rebecca J Lawton

    Full Text Available Intensive cultivation of freshwater macroalgae is likely to increase with the development of an algal biofuels industry and algal bioremediation. However, target freshwater macroalgae species suitable for large-scale intensive cultivation have not yet been identified. Therefore, as a first step to identifying target species, we compared the productivity, growth and biochemical composition of three species representative of key freshwater macroalgae genera across a range of cultivation conditions. We then selected a primary target species and assessed its competitive ability against other species over a range of stocking densities. Oedogonium had the highest productivity (8.0 g ash free dry weight m⁻² day⁻¹, lowest ash content (3-8%, lowest water content (fresh weigh: dry weight ratio of 3.4, highest carbon content (45% and highest bioenergy potential (higher heating value 20 MJ/kg compared to Cladophora and Spirogyra. The higher productivity of Oedogonium relative to Cladophora and Spirogyra was consistent when algae were cultured with and without the addition of CO₂ across three aeration treatments. Therefore, Oedogonium was selected as our primary target species. The competitive ability of Oedogonium was assessed by growing it in bi-cultures and polycultures with Cladophora and Spirogyra over a range of stocking densities. Cultures were initially stocked with equal proportions of each species, but after three weeks of growth the proportion of Oedogonium had increased to at least 96% (±7 S.E. in Oedogonium-Spirogyra bi-cultures, 86% (±16 S.E. in Oedogonium-Cladophora bi-cultures and 82% (±18 S.E. in polycultures. The high productivity, bioenergy potential and competitive dominance of Oedogonium make this species an ideal freshwater macroalgal target for large-scale production and a valuable biomass source for bioenergy applications. These results demonstrate that freshwater macroalgae are thus far an under-utilised feedstock with

  4. Accumulation of radionuclides in selected marine biota from Manjung coastal area

    Science.gov (United States)

    Abdullah, Anisa; Hamzah, Zaini; Saat, Ahmad; Wood, Ab. Khalik; Alias, Masitah

    2015-04-01

    Distribution of radionuclides from anthropogenic activities has been intensively studied due to the accumulation of radionuclides in marine ecosystem. Manjung area is affected by rapid population growth and socio-economic development such as heavy industrial activities including coal fired power plant, iron foundries, port development and factories, agricultural runoff, waste and toxic discharge from factories.It has radiological risk and toxic effect when effluent from the industries in the area containing radioactive materials either being transported to the atmosphere and deposited back over the land or by run off to the river and flow into coastal area and being absorbed by marine biota. Radionuclides presence in the marine ecosystem can be adversely affect human health when it enters the food chain. This study is focusing on the radionuclides [thorium (Th), uranium (U), radium-226 (226Ra), radium-228 (228Ra) and potassium-40 (40K)] content in marine biota and sea water from Manjung coastal area. Five species of marine biota including Johnius dussumieri (Ikan Gelama), Pseudorhombus malayanus (Ikan Sebelah), Arius maculatus (Ikan Duri), Portunus pelagicus (Ketam Renjong) and Charybdis natator (Ketam Salib) were collected during rainy and dry seasons. Measurements were carried out using Inductively Coupled Plasma Mass Spectrometer (ICPMS). The results show that the concentration of radionuclides varies depends on ecological environment of respective marine biota species. The concentrations and activity concentrations are used for the assessment of potential internal hazard index (Hin), transfer factor (TF), ingestion dose rate (D) and health risk index (HRI) to monitor radiological risk for human consumption.

  5. Accumulation of radionuclides in selected marine biota from Manjung coastal area

    Energy Technology Data Exchange (ETDEWEB)

    Abdullah, Anisa, E-mail: coppering@ymail.com; Hamzah, Zaini; Wood, Ab. Khalik [Faculty of Applied Sciences, Universiti Teknologi MARA, 40450, Shah Alam, Selangor (Malaysia); Saat, Ahmad [Faculty of Applied Sciences, Universiti Teknologi MARA, 40450, Shah Alam, Selangor (Malaysia); Institute of Science, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia); Alias, Masitah [TNB Reasearch Sdn. Bhd., Kawasan Institusi Penyelidikan, 43000 Kajang, Selangor (Malaysia)

    2015-04-29

    Distribution of radionuclides from anthropogenic activities has been intensively studied due to the accumulation of radionuclides in marine ecosystem. Manjung area is affected by rapid population growth and socio-economic development such as heavy industrial activities including coal fired power plant, iron foundries, port development and factories, agricultural runoff, waste and toxic discharge from factories.It has radiological risk and toxic effect when effluent from the industries in the area containing radioactive materials either being transported to the atmosphere and deposited back over the land or by run off to the river and flow into coastal area and being absorbed by marine biota. Radionuclides presence in the marine ecosystem can be adversely affect human health when it enters the food chain. This study is focusing on the radionuclides [thorium (Th), uranium (U), radium-226 ({sup 226}Ra), radium-228 ({sup 228}Ra) and potassium-40 ({sup 40}K)] content in marine biota and sea water from Manjung coastal area. Five species of marine biota including Johnius dussumieri (Ikan Gelama), Pseudorhombus malayanus (Ikan Sebelah), Arius maculatus (Ikan Duri), Portunus pelagicus (Ketam Renjong) and Charybdis natator (Ketam Salib) were collected during rainy and dry seasons. Measurements were carried out using Inductively Coupled Plasma Mass Spectrometer (ICPMS). The results show that the concentration of radionuclides varies depends on ecological environment of respective marine biota species. The concentrations and activity concentrations are used for the assessment of potential internal hazard index (H{sub in}), transfer factor (TF), ingestion dose rate (D) and health risk index (HRI) to monitor radiological risk for human consumption.

  6. Determinants of habitat selection by hatchling Australian freshwater crocodiles.

    Directory of Open Access Journals (Sweden)

    Ruchira Somaweera

    Full Text Available Animals almost always use habitats non-randomly, but the costs and benefits of using specific habitat types remain unknown for many types of organisms. In a large lake in northwestern Australia (Lake Argyle, most hatchling (<12-month-old freshwater crocodiles (Crocodylus johnstoni are found in floating vegetation mats or grassy banks rather than the more widely available open banks. Mean body sizes of young crocodiles did not differ among the three habitat types. We tested four potential explanations for non-random habitat selection: proximity to nesting sites, thermal conditions, food availability, and exposure to predation. The three alternative habitat types did not differ in proximity to nesting sites, or in thermal conditions. Habitats with higher food availability harboured more hatchlings, and feeding rates (obtained by stomach-flushing of recently-captured crocodiles were highest in such areas. Predation risk may also differ among habitats: we were twice as likely to capture a crocodile after seeing it in open-bank sites than in the other two habitat types. Thus, habitat selection of hatchling crocodiles in this system may be driven both by prey availability and by predation risk.

  7. Distribution, source identification and risk assessment of selected metals in sediments from freshwater lake

    Institute of Scientific and Technical Information of China (English)

    Javed Iqbal; Munir H. Shah; Nazia Shaheen

    2015-01-01

    abstract This study is based on the assessment of distribution, source apportionment and risk assessment of selected metals in freshly deposited sediments from freshwater lake, Pakistan. Composite sediments were collected and processed to assess Ca(NO3)2-extractable and acid-extractable levels of the metals in the sediments using flame atomic absorption spectrophotometry. Enrichment factors (EF), geoaccumu-lation indices (Igeo), contamination factors (Cf) and degree of contamination (Cdeg) were computed to estimate the degree of contamination. The potential ecological risk was assessed using sediment quality guidelines and mean-ERM-quotient (m-ERM-Q). On the average basis, acid-extractable metals followed the decreasing concentration order: Ca>Mg>Fe>K>Mn>Na>Sr>Zn>Pb>Cr>Co>Cu>-Li>Cd, whereas, the Ca(NO3)2-extractable levels were: Na>Pb>Cd>Sr>Co>Cr>K>Mg>-Cu>Zn>Li>Ca>Fe>Mn. The highest Ca(NO3)2 extractable concentrations were observed for Na, Pb and Cd, while that of Ca, Fe and Mn were the least. EF showed very high and extremely high enrichment of Pb and Cd, respectively, while Ca, Co, Cr, Li, Mg, Mn, Sr and Zn manifested moderate enrichment;the Igeo results revealed moderate to strong and strong to extreme pollution for Pb and Cd, respectively; and the Cf study showed moderate, considerable and very high contamination by Co, Pb and Cd, respectively. The Cdeg revealed very high degree of contamination in the sediments as a whole. Principal component analysis (PCA) and cluster analysis (CA) showed considerable anthropogenic contributions of Cd, Pb, Co, Mn, K, Zn and Li in the sediments. Measured levels of Cd and Pb exceeded ERL values, manifesting occasional adverse biological effects to the dwelling biota. Moreover, the m-ERM-Q study manifested 21%probability of toxicity in the sediments.

  8. Acute toxicity of organophosphate insecticide, dichlorvos in relation to selected water hardness for the freshwater zooplankters.

    Science.gov (United States)

    Gupta, Ashok Kumar; Verma, Girraj Prasad; Jain, Khyali Lal

    2008-11-01

    Toxicity of organophosphate insecticide, i.e. dichlorvos has been investigated in relation to selected water hardness for the freshwater zooplankters such as Moina, Daphnia, cyclops and nauplii. Results revealed that dichlorvos was highly toxic to the tested zooplankters, as the LC50 values are noticed in ppb. Trend of sensitivity for different zooplankters to dichlorvos was recorded as Moina < Daphnia < nauplii < cyclops. The LC50 were found to change significantly with the change in water hardness. The zooplankters were more susceptible to dichlorvos at water hardness of 275 mgl(-1) as compared to water hardness of 540 mgl(-1) as revealed from low LC50 values. The range of safe dischargeable concentrations (1.063-1.137ppb) were too low as compared to harmless or safe concentrations (43.895-89.194 ppb) for the zooplankters at both the hardness. PMID:19297975

  9. 锌对淡水生物的毒性特征与水质基准的研究%Toxicity Characteristic of Zinc to Freshwater Biota and Its Water Quality Criteria

    Institute of Scientific and Technical Information of China (English)

    吴丰昌; 冯承莲; 曹宇静; 张瑞卿; 李会仙; 廖海清; 赵晓丽

    2011-01-01

    criteria for chronic toxicity to fishes, crustaceans and other invertebrates were 36.9 μg·L-1, 12.9 μg·L-1 and 14.8 μg·L-1, respectively. The results showed that, to some extent, full protection can not be provided by the present water quality criteria of Zn for Chinese freshwater life. This study might provide useful data support for deriving water quality criteria for protecting aquatic biota in China.

  10. Baseline assessment of physical characteristics, aquatic biota, and selected water-quality properties at the reach and mesohabitat scale for reaches of Big Cypress, Black Cypress, and Little Cypress Bayous, Big Cypress Basin, northeastern Texas, 2010–11

    Science.gov (United States)

    Braun, Christopher L.; Moring, James B.

    2013-01-01

    In 2010 and 2011, the U.S. Geological Survey (USGS), in cooperation with the Northeast Texas Municipal Water District and the Texas Commission on Environmental Quality, did a baseline assessment of physical characteristics and aquatic biota (fish and mussels) collected at the mesohabitat scale for reaches of Big Cypress, Black Cypress, and Little Cypress Bayous in the Big Cypress Basin in northeastern Texas, and measured selected water-quality properties in isolated pools in Black Cypress and Little Cypress. All of the data were collected in the context of prescribed environmental flows. The information acquired during the course of the study will support the long-term monitoring of biota in relation to environmental flow prescriptions for Big Cypress Bayou, Black Cypress Bayou, and Little Cypress Bayou. Data collection and analysis were done at mesohabitat- and reach-specific scales, where a mesohabitat is defined as a discrete area within a stream that exhibits unique depth, velocity, slope, substrate, and cover.

  11. Baseline assessment of physical characteristics, aquatic biota, and selected water-quality properties at the reach and mesohabitat scale for reaches of Big Cypress, Black Cypress, and Little Cypress Bayous, Big Cypress Basin, northeastern Texas, 2010–11

    Science.gov (United States)

    Braun, Christopher L.; Moring, James B.

    2013-01-01

    In 2010 and 2011, the U.S. Geological Survey (USGS), in cooperation with the Northeast Texas Municipal Water District and the Texas Commission on Environmental Quality, did a baseline assessment of physical characteristics and aquatic biota (fish and mussels) collected at the mesohabitat scale for reaches of Big Cypress, Black Cypress, and Little Cypress Bayous in the Big Cypress Basin in northeastern Texas, and measured selected water-quality properties in isolated pools in Black Cypress and Little Cypress. All of the data were collected in the context of prescribed environmental flows. The information acquired during the course of the study will support the long-term monitoring of biota in relation to environmental flow prescriptions for Big Cypress Bayou, Black Cypress Bayou, and Little Cypress Bayou. Data collection and analysis were done at mesohabitat- and reach-specific scales, where a mesohabitat is defined as a discrete area within a stream that exhibits unique depth, velocity, slope, substrate, and cover. Biological and physical characteristic data were collected from two sites on Big Cypress Bayou, and one site on both Black Cypress Bayou and Little Cypress Bayou. The upstream reach of Big Cypress Bayou (USGS station 07346015 Big Cypress Bayou at confluence of French Creek, Jefferson, Texas) is hereinafter referred to as the Big Cypress 02 site. The downstream site on Big Cypress Bayou (USGS station 07346017 Big Cypress Bayou near U.S. Highway 59 near Jefferson, Tex.) is hereinafter referred to as the Big Cypress 01 site and was sampled exclusively for mussels. The sites on Black Cypress Bayou (USGS station 07346044 Black Cypress Bayou near U.S. Highway 59 near Jefferson, Tex.) and Little Cypress Bayou (USGS station 07346071 Little Cypress Bayou near U.S. Highway 59 near Jefferson, Tex.) are hereinafter referred to as the Black Cypress and Little Cypress sites, respectively. A small range of streamflows was targeted for data collection, including a

  12. The importance of environmental quality and catch potential to fishing site selection by freshwater anglers in Mississippi

    Science.gov (United States)

    Schramm, H.L.; Gerard, P.D.; Gill, D.A.

    2003-01-01

    We measured the importance of 24 fishing site attributes to Mississippi freshwater anglers. Factor analysis identified four multiattribute factors as important in the selection of fishing location: CLEAN ENVIRONMENT CATCH, COST AND HARVEST and AMENITIES AND SAFETY. In general, the importance of site selection factors differed little among anglers grouped by preferred type of fish, preferred fishing location (lakes and reservoirs, rivers and streams, ponds, or reservoir tailwaters), usual manner of fishing (engine-powered boat, nonpowered boat, or shore), or change in fishing frequency. COST AND HARVEST was more important to anglers with high harvest orientations. We found low correlations between site selection factor importance scores and angler age, fishing frequency, fishing expenditures, or fishing motivation factors. We suggest that the general lack of differences in site selection factors among angler groups indicates that management strategies to improve fishing site attributes should benefit all angler groups. Clean fishing environments and awareness of the availability of desired sport fishes were "very" or "extremely" important to fishing site selection by more than 70% of Mississippi freshwater anglers and should be priority management objectives.

  13. Initial Evidence for Adaptive Selection on the NADH Subunit Two of Freshwater Dolphins by Analyses of Mitochondrial Genomes

    Science.gov (United States)

    Caballero, Susana; Duchêne, Sebastian; Garavito, Manuel F.; Slikas, Beth; Baker, C. Scott

    2015-01-01

    A small number of cetaceans have adapted to an entirely freshwater environment, having colonized rivers in Asia and South America from an ancestral origin in the marine environment. This includes the ‘river dolphins’, early divergence from the odontocete lineage, and two species of true dolphins (Family Delphinidae). Successful adaptation to the freshwater environment may have required increased demands in energy involved in processes such as the mitochondrial osmotic balance. For this reason, riverine odontocetes provide a compelling natural experiment in adaptation of mammals from marine to freshwater habitats. Here we present initial evidence of positive selection in the NADH dehydrogenase subunit 2 of riverine odontocetes by analyses of full mitochondrial genomes, using tests of selection and protein structure modeling. The codon model with highest statistical support corresponds to three discrete categories for amino acid sites, those under positive, neutral, and purifying selection. With this model we found positive selection at site 297 of the NADH dehydrogenase subunit 2 (dN/dS>1.0,) leading to a substitution of an Ala or Val from the ancestral state of Thr. A phylogenetic reconstruction of 27 cetacean mitogenomes showed that an Ala substitution has evolved at least four times in cetaceans, once or more in the three ‘river dolphins’ (Families Pontoporidae, Lipotidae and Inidae), once in the riverine Sotalia fluviatilis (but not in its marine sister taxa), once in the riverine Orcaella brevirostris from the Mekong River (but not in its marine sister taxa) and once in two other related marine dolphins. We located the position of this amino acid substitution in an alpha-helix channel in the trans-membrane domain in both the E. coli structure and Sotalia fluviatilis model. In E. coli this position is located in a helix implicated in a proton translocation channel of respiratory complex 1 and may have a similar role in the NADH dehydrogenases of

  14. Initial Evidence for Adaptive Selection on the NADH Subunit Two of Freshwater Dolphins by Analyses of Mitochondrial Genomes.

    Directory of Open Access Journals (Sweden)

    Susana Caballero

    Full Text Available A small number of cetaceans have adapted to an entirely freshwater environment, having colonized rivers in Asia and South America from an ancestral origin in the marine environment. This includes the 'river dolphins', early divergence from the odontocete lineage, and two species of true dolphins (Family Delphinidae. Successful adaptation to the freshwater environment may have required increased demands in energy involved in processes such as the mitochondrial osmotic balance. For this reason, riverine odontocetes provide a compelling natural experiment in adaptation of mammals from marine to freshwater habitats. Here we present initial evidence of positive selection in the NADH dehydrogenase subunit 2 of riverine odontocetes by analyses of full mitochondrial genomes, using tests of selection and protein structure modeling. The codon model with highest statistical support corresponds to three discrete categories for amino acid sites, those under positive, neutral, and purifying selection. With this model we found positive selection at site 297 of the NADH dehydrogenase subunit 2 (dN/dS>1.0, leading to a substitution of an Ala or Val from the ancestral state of Thr. A phylogenetic reconstruction of 27 cetacean mitogenomes showed that an Ala substitution has evolved at least four times in cetaceans, once or more in the three 'river dolphins' (Families Pontoporidae, Lipotidae and Inidae, once in the riverine Sotalia fluviatilis (but not in its marine sister taxa, once in the riverine Orcaella brevirostris from the Mekong River (but not in its marine sister taxa and once in two other related marine dolphins. We located the position of this amino acid substitution in an alpha-helix channel in the trans-membrane domain in both the E. coli structure and Sotalia fluviatilis model. In E. coli this position is located in a helix implicated in a proton translocation channel of respiratory complex 1 and may have a similar role in the NADH dehydrogenases of

  15. Baseline assessment of physical characteristics, aquatic biota, and selected water-quality properties at the reach and mesohabitat scale for three stream reaches in the Big Cypress Basin, northeastern Texas, 2010-11

    Science.gov (United States)

    Braun, Christopher L.; Moring, James B.

    2013-01-01

    The U.S. Geological Survey (USGS), in cooperation with the Northeast Texas Municipal Water District and the Texas Commission on Environmental Quality, did a baseline assessment in 2010-11 of physical characteristics and selected aquatic biota (fish and mussels) collected at the mesohabitat scale for three stream reaches in the Big Cypress Basin in northeastern Texas for which environmental flows have been prescribed. Mesohabitats are visually distinct units of habitat within the stream with unique depth, velocity, slope, substrate, and cover. Mesohabitats in reaches of Big Cypress, Black Cypress, and Little Cypress Bayous were evaluated to gain an understanding of how fish communities and mussel populations varied by habitat. Selected water-quality properties were also measured in isolated pools in Black Cypress and Little Cypress. All of the data were collected in the context of the prescribed environmental flows. The information acquired during the study will support the long-term monitoring of biota in relation to the prescribed environmental flows.

  16. Selection of spatial scale for assessing impacts of groundwater-based water supply on freshwater resources

    DEFF Research Database (Denmark)

    Hybel, Anne-Marie; Godskesen, Berit; Rygaard, Martin

    2015-01-01

    sub-river basin data, may dramatically underestimate the actual impact on the water resource. Furthermore, this study discusses the strengths and shortcomings of the applied indicator approaches. A sensitivity analysis demonstrates that although WSI has the highest environmental relevance, it also has...... the highest uncertainty, as it requires estimations of non-measurable environmental water requirements. Hence, the development of a methodology to obtain more site-specific and relevant estimations of environmental water requirements should be prioritized. Finally, the demarcation of the groundwater resource......Indicators of the impact on freshwater resources are becoming increasingly important in the evaluation of urban water systems. To reveal the importance of spatial resolution, we investigated how the choice of catchment scale influenced the freshwater impact assessment. Two different indicators were...

  17. 中美淡水生物区系中汞物种敏感度分布比较%Comparison of mercury species sensitivity distributions of freshwater biota in China and the United States

    Institute of Scientific and Technical Information of China (English)

    李会仙; 张瑞卿; 吴丰昌; 郭广慧; 冯承莲

    2012-01-01

    Based on single-species freshwater acute toxicity data in China and the United states, species sensitivity distributions (SSDs) of vertebrates (including fish) and invertebrates (including arthropods and non-arthropod invertebrates) to mercury were constructed, and species sensitivity to mercury in these two countries were compared. The results of this study indicated that there was no significant difference between sensitivity distributions of the Chinese and American taxa. However, the hazardous concentration for 5% of the species (HC5) range of Chinese species to short-term mercury exposure was lower than that of the American species, especially for non-arthropod invertebrates. HC5 for American non-arthropod invertebrates to mercury was 7.4 times larger than that for the corresponding Chinese species. Under the 95% protection level and including all the species, the tested invertebrates were more sensitive to mercury than the vertebrates in both China and the United States. However, in the lower taxonomic classification level, the sensitivity decreased in the order of arthropod non-arthropod invertebrates fish in China, but the order was arthropods fish non-arthropod invertebrates in the United States. Therefore, in determining the water quality criteria based on the sensitivity of all the species, we should also consider the influence of SSD of individual groups. The water quality criteria derived from the species sensitivity distribution of American species may make the aquatic species in China out of protection.%通过收集无机汞对中国与美国淡水水生生物的毒性数据,构建了脊椎动物(包括鱼类)、无脊椎动物(包括节肢动物和非节肢无脊椎动物)及所有物种对汞的物种敏感度分布(SSD:species sensitivity distributions)曲线,并在此基础上对中国和美国不同类别生物对汞的敏感性分布进行了分析.结果表明:中国与美国各类生物及所有物种对汞

  18. A freshwater species wintering in a brackish environment: Habitat selection and diet of Slavonian grebes in the southern Baltic Sea

    Science.gov (United States)

    Sonntag, Nicole; Garthe, Stefan; Adler, Sven

    2009-09-01

    After the breeding season, Slavonian grebes ( Podiceps auritus) leave their freshwater breeding habitats and migrate to wintering grounds in marine or brackish waters. The most important wintering area in northwestern Europe is located in the southern Baltic Sea, with the largest concentrations in the offshore area of the Pommeranian Bight. Analysis of ship-based surveys revealed that the habitat selection of Slavonian grebes in this brackish area is significantly influenced by water depth and bottom sediment type. The grebes prefer shallow waters of 4-14 m depth and occur only over sandy sediments. While the diving depths of endothermic animals is limited due to energetic constraints and thermoregulation, sediment type is regarded to be a proxy for food choice. The diet of Slavonian grebes in the Pomeranian Bight consists mainly of demersal gobies (Gobiidae) that frequently occur over sandy bottom substrates.

  19. Selectivity of solid phase extraction of freshwater dissolved organic matter and its effect on ultrahigh resolution mass spectra.

    Science.gov (United States)

    Raeke, Julia; Lechtenfeld, Oliver J; Wagner, Martin; Herzsprung, Peter; Reemtsma, Thorsten

    2016-07-13

    Solid phase extraction (SPE) is often used for enrichment and clean-up prior to analysis of dissolved organic matter (DOM) by electrospray ionization (ESI) coupled to ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). It is generally accepted that extraction by SPE is not quantitative with respect to carbon concentration. However, little information is available on the selectivity of different SPE sorbents and the resulting effect for the acquired DOM mass spectra. Freshwater samples were extracted by the widely used PPL, HLB and C18 sorbents and the molecular composition and size distribution of the DOM in the extracts and in the permeates was compared to the original sample. Dissolved organic carbon (DOC) recoveries ranged between 20% and 65% for the three tested SPE sorbents. Size-exclusion chromatography coupled to organic carbon detection (SEC-OCD) revealed that limited recovery by PPL and HLB was primarily due to incomplete elution of a fraction of apparent high molecular weight from the solid phase. In contrast, incomplete retention on the solid phase, mainly observed for the C18 cartridge, was attributed to a fraction of low molecular weight. The FT-ICR mass spectra of the original sample and the SPE extracts did not differ significantly in their molecular weight distribution, but they showed sorbent specific differences in the degree of oxygenation and saturation. We concluded that the selective enrichment of freshwater DOM by SPE is less critical for subsequent FT-ICR MS analysis, because those fractions that are not sufficiently recovered have comparatively small effects on the mass spectra. This was confirmed by the extraction of model compounds, showing that very polar and small molecules are poorly extracted, but also have a low response in ESI-MS. Of the three tested SPE cartridges the PPL material offered the best properties for DOM enrichment for subsequent FT-ICR MS analysis as it minimizes too strong and

  20. Toxicity, sublethal effects, and potential modes of action of select fungicides on freshwater fish and invertebrates

    Science.gov (United States)

    Elskus, Adria A.

    2012-01-01

    organic matter in sediment and soils, it is particularly important to determine their effects on freshwater mussels and other freshwater benthic invertebrates in contact with sediments, as available toxicity studies with pelagic species, mainly Daphnia magna, may not be representative of these benthic organisms. Finally, there is a critical need for studies of the chronic effects of fungicides on reproduction, immunocompetence, and ecosystem function; sublethal endpoints with population and community-level relevance.

  1. Literature review of the concentration ratios of selected radionuclides in freshwater and marine fish

    International Nuclear Information System (INIS)

    Concentration ratios (CR's) used for modeling the uptake and food chain transport of radionuclides in fish have usually been conservative; that is, at the high end of reported values. This practice ensures that the dose to the consumer of contaminated fish will not be underestimated. In many models, however, conservative values have been used for all variables that have any uncertainty associated with them. As a result the dose to the consumer is overestimated. Realistic CR values need to be developed to establish model parameters that will accurately reflect tissue burdens in fish and resulting dose rates to consumers. This report reviews and summarizes published literature on the uptake and distribution of stable and radioactive isotopes of 26 elements. Based on this review, we have made recommendations on CR values to be used for modeling the accumulation of radionuclides in fish. Our recommendations are compared with CR values reported in other publications. A generic discussion of abiotic and biotic factors that influence CR values is provided so that CR values may be adjusted based on site-specific characteristics of the fishes habitat. Recommended CR values for freshwater fish and for marine fish are listed. Although this report emphasizes radionuclides, it is applicable to stable elements as well

  2. Literature review of the concentration ratios of selected radionuclides in freshwater and marine fish

    Energy Technology Data Exchange (ETDEWEB)

    Poston, T.M.; Klopfer, D.C.

    1986-09-01

    Concentration ratios (CR's) used for modeling the uptake and food chain transport of radionuclides in fish have usually been conservative; that is, at the high end of reported values. This practice ensures that the dose to the consumer of contaminated fish will not be underestimated. In many models, however, conservative values have been used for all variables that have any uncertainty associated with them. As a result the dose to the consumer is overestimated. Realistic CR values need to be developed to establish model parameters that will accurately reflect tissue burdens in fish and resulting dose rates to consumers. This report reviews and summarizes published literature on the uptake and distribution of stable and radioactive isotopes of 26 elements. Based on this review, we have made recommendations on CR values to be used for modeling the accumulation of radionuclides in fish. Our recommendations are compared with CR values reported in other publications. A generic discussion of abiotic and biotic factors that influence CR values is provided so that CR values may be adjusted based on site-specific characteristics of the fishes habitat. Recommended CR values for freshwater fish and for marine fish are listed. Although this report emphasizes radionuclides, it is applicable to stable elements as well.

  3. Short-term bioconcentration studies of Np in freshwater biota

    International Nuclear Information System (INIS)

    Short-term laboratory exposures were conducted to determine the potential accumulation of Np in aquatic organisms. Concentration factors were highest in green algae. Daphnia magna, a filter-feeding crustacean, accumulated Np at levels one order of magnitude greater than the amphipod Gammarus sp., an omnivorous substrate feeder. Accumulation of Np in juvenile rainbow trout (Oncorhynchus mykiss) was highest in carcass (generally greater than 78% of the total body burden) and lowest in fillets. Recommended concentration factors for Np, based on fresh weight, were 300 for green algae, 100 for filter-feeding invertebrates, for nonfilter-feeding invertebrates, 10 for whole fish, and one for fish flesh

  4. Size-selective feeding on phytoplankton by two morpho-groups of the small freshwater fish Amblypharyngodon mola.

    Science.gov (United States)

    Nandi, S; Saikia, S K

    2015-08-01

    Two morpho-groups (i.e., small, MGS and big, MGL) of the small freshwater fish Amblypharyngodon mola were studied for their feeding behaviour in the natural environment. Both the morpho-groups fed on a variety of phytoplankton including Cyanophyceae, Chlorophyceae, Bacillariophyceae and Euglenophyceae. The fish had more Chlorophyceae and Bacillariophyceae in their gut than other phytoplankton. Costello's selectivity plots revealed that the MGS fed on the smaller phytoplankters (2-6 µm in size), whereas the MGL fed on both the small and large (up to 12 µm in size) phytoplankters. The differences in mouth areas between the two morpho-groups were explained as a possible reason of size-selective feeding and contribute to overcome gape limitation in A. mola. This is further accompanied by the uniform pore size of the gills (2 µm) in all the morpho-groups. This study concluded that A. mola exhibits a size-dependent feeding strategy regulated by gape limitation at the ingestion level. With ontogenetic shifts, flexibility appears to overcome such a limitation in the MGL, having a wider mouth area supported by jaw opening ability. PMID:26084383

  5. Selective pressure of antibiotics on ARGs and bacterial communities in manure-polluted freshwater-sediment microcosms

    Directory of Open Access Journals (Sweden)

    Wenguang eXiong

    2015-03-01

    Full Text Available The aim of this study was to investigate selective pressure of antibiotics on antibiotic resistance genes (ARGs and bacterial communities in manure-polluted aquatic environment. Three treatment groups were set up in freshwater-sediment microcosms: tetracyclines group, sulfonamides group and fluoroquinolones group. Sediment and water samples were collected on day 14 after treatment. Antibiotic concentrations, ARGs abundances and bacterial community composition were analyzed. Antibiotic concentrations were determined by ultra-performance liquid chromatography-electrospray tandem mass spectrometry. ARGs abundances were quantified by real time quantitative PCR. Bacterial community composition was analyzed based on amplicon sequencing. Of the three classes of antibiotics analyzed in the treatment groups, accumulation amounts were tetracyclines> fluoroquinolone> sulfonamides in the sediment samples, while they were sulfonamides> fluoroquinolone> tetracyclines in the water samples. In the treatment groups, the relative abundances of some tet resistance genes (tet(W and tet(X and plasmid-mediated quinolone resistance (PMQR genes (oqx(B and aac(6’-Ib in sediment samples were significantly higher than those in the paired water samples. Tetracyclines significantly selected the bacterial classes including Gammaproteobacteria, Clostridia, and the genera including Salmonella, Escherichia/Shigella, Clostridium, Stenotrophomonas in sediment samples. The significant selection on bacterial communities posed by sulfonamides and fluoroquinolones was also observed. The results indicated that sediment may supply an ideal setting for maintenance and persistence of tet resistance genes (tet(W and tet(X and PMQR genes (oqx(B and aac(6’-Ib under antibiotic pollution. The results also highlighted that antibiotics significantly selected specific bacterial communities including the taxa associated with opportunistic pathogens.

  6. Co-selection of antibiotic and heavy metal resistance in freshwater bacteria

    Directory of Open Access Journals (Sweden)

    Andrea Di Cesare

    2016-04-01

    Full Text Available Antibiotic resistant bacteria are found in most environments, especially in highly anthropized waters. A direct correlation between human activities (e.g., pollution and spread and persistence of antibiotic resistant bacteria (ARB and resistance genes (ARGs within the resident bacterial communities appears more and more obvious. Furthermore, the threat posed for human health by the presence of ARB and ARGs in these environments is enhanced by the risk of horizontal gene transfer of resistance genes to human pathogens. Although the knowledge on the spread of antibiotic resistances in waters is increasing, the understanding of the driving factors determining the selection for antibiotic resistance in the environment is still scarce. Antibiotic pollution is generally coupled with contamination by heavy metals (HMs and other chemicals, which can also promote the development of resistance mechanisms, often through co-selecting for multiple resistances. The co-selection of heavy metal resistance genes and ARGs in waters, sediments, and soils, increases the complexity of the ecological role of ARGs, and reduces the effectiveness of control actions. In this mini-review we present the state-of-the-art of the research on antibiotic- and HM-resistance and their connection in the environment, with a focus on HM pollution and aquatic environments. We review the spread and the persistence of HMs and/or ARB, and how it influences their respective gene co-selection. In the last chapter, we propose Lake Orta, a system characterized by an intensive HM pollution followed by a successful restoration of the chemistry of the water column, as a study-site to evaluate the spread and selection of HMs and antibiotic resistances in heavily disturbed environments.

  7. Direct and Indirect Evidence of Size-Selective Grazing on Pelagic Bacteria by Freshwater Nanoflagellates

    OpenAIRE

    Šimek, Karel; Chrzanowski, Thomas H.

    1992-01-01

    Size-selective grazing of three heterotrophic nanoflagellates (with cell sizes of 21, 44, and 66 μm3) isolated from Lake Arlington, Texas was examined by using a natural mixture of fluorescence labelled lake bacteria. Sizes of ingested bacteria in food vacuoles were directly measured. Larger bacterial cells were ingested at a frequency much higher than that at which they occurred in the assemblage, indicating preferential flagellate grazing on the larger size classes within the lake bacteriop...

  8. Accumulation of polychlorinated biphenyls in the freshwater fish, crucian, from the Han river and the Kum river, Korea

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, G.H.; Kim, Y.B.; Moon, J.Y.; Lee, S.I.; Kim, H.; Song, H. [Pusan National Univ. (Korea)

    2004-09-15

    Even though polychlorinated biphenyls(PCBs) were prohibited from producing and using for a long time, it is still identified in the every environmental media including biota. Since PCBs are lipophilic and persistent, they concentrate readily in the tissue and accumulate exponentially as they move through the food chain. Crucian (Carassius auratus) is most widely living freshwater fish in Korea. So crucian was selected as a representative freshwater fish in this study to determine the accumulation level and distribution characteristics of PCBs. In this study, we attempted to investigate the accumulation profile of individual PCB congeners in the muscle of freshwater fish crucian from the two major rivers, the Han River and Kum River, in Korea.

  9. Computerizing marine biota: a rational approach

    Digital Repository Service at National Institute of Oceanography (India)

    Chavan, V.S.; Chandramohan, D.; Parulekar, A.H.

    Data on marine biota while being extensive are also patchy and scattered; thus making retrieval and dissemination of information time consuming. This emphasise the need for computerizing information on marine biota with the objective to collate...

  10. Biota-Sediment Accumulation Factor Data

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Biota-Sediment Accumulation Factor contains approximately 20,000 biota-sediment accumulation factors (BSAFs) from 20 locations (mostly Superfund sites) for...

  11. A low-density SNP array for analyzing differential selection in freshwater and marine populations of threespine stickleback (Gasterosteus aculeatus)

    DEFF Research Database (Denmark)

    Ferchaud, Anne-Laure; Pedersen, Susanne H.; Bekkevold, Dorte;

    2014-01-01

    Background: The threespine stickleback (Gasterosteus aculeatus) has become an important model species for studying both contemporary and parallel evolution. In particular, differential adaptation to freshwater and marine environments has led to high differentiation between freshwater and marine......: RAD (Restriction site Associated DNA) sequencing of sixty individuals representing two freshwater and one marine population led to the identification of 33,993 SNP markers. Ninety-six of these were chosen for the low-density SNP array, among which 70 represented SNPs under putatively directional...... have developed a cost-efficient low-density SNP array that allows for rapid screening of polymorphisms in threespine stickleback. The array provides a valuable tool for analyzing adaptive divergence between freshwater and marine stickleback populations beyond the well-established candidate gene...

  12. Isotope and ion selectivity in reverse osmosis desalination: geochemical tracers for man-made freshwater.

    Science.gov (United States)

    Kloppmann, Wolfram; Vengosh, Avner; Guerrot, Catherine; Millot, Romain; Pankratov, Irena

    2008-07-01

    A systematic measurement of ions and 2H/1H, 7Li/6Li, 11B/10B, 18O/ 16O, and 87Sr/86Sr isotopes in feed-waters, permeates, and brines from commercial reverse osmosis (RO) desalination plants in Israel (Ashkelon, Eilat, and Nitzana) and Cyprus (Larnaca) reveals distinctive geochemical and isotopic fingerprints of fresh water generated from desalination of seawater (SWRO) and brackish water (BWRO). The degree of isotope fractionation during the passage of water and solutes through the RO membranes depends on the medium (solvent-water vs. solutes), chemical speciation of the solutes, their charge, and their mass difference. O, H, and Sr isotopes are not fractionated during the RO process. 7Li is preferentially rejected in low pH RO, and B isotope fractionation depends on the pH conditions. Under low pH conditions, B isotopes are not significantly fractionated, whereas at high pH, RO permeates are enriched by 20 per thousand in 11B due to selective rejection of borate ion and preferential permeation of 11B-enriched boric acid through the membrane. The specific geochemical and isotopic fingerprints of SWRO provide a unique tool for tracing "man-made" fresh water as an emerging recharge component of natural water resources.

  13. Direct and Indirect Evidence of Size-Selective Grazing on Pelagic Bacteria by Freshwater Nanoflagellates

    Science.gov (United States)

    Šimek, Karel; Chrzanowski, Thomas H.

    1992-01-01

    Size-selective grazing of three heterotrophic nanoflagellates (with cell sizes of 21, 44, and 66 μm3) isolated from Lake Arlington, Texas was examined by using a natural mixture of fluorescence labelled lake bacteria. Sizes of ingested bacteria in food vacuoles were directly measured. Larger bacterial cells were ingested at a frequency much higher than that at which they occurred in the assemblage, indicating preferential flagellate grazing on the larger size classes within the lake bacterioplankton. Water samples were collected biweekly from June through September, 1989, fractionated by filtration, and incubated for 40 h at in situ temperatures. The average bacterial size was always larger in water which was passed through 1-μm-pore-size filters (1-μm-filtered water) (which was predator free) than in 5-μm-filtered water (which contained flagellates only) or in unfiltered water (in which all bacterivores were present). The increase of bacterial-cell size in 1-μm-filtered water was caused by a shift in the size structure of the bacterioplankton population. Larger cells became more abundant in the absence of flagellate grazing. PMID:16348811

  14. Bioeconomic analysis of selected conservation practices on soil erosion and freshwater fisheries

    Science.gov (United States)

    Westra, J.V.; Zimmerman, J.K.H.; Vondracek, B.

    2005-01-01

    Farmers can generate environmental benefits (improved water quality and fisheries and wildlife habitat), but they may not be able to quantify them. Furthermore, farmers may reduce their incomes from managing lands to produce these positive externalities but receive little monetary compensation in return. This study simulated the relationship between agricultural practices, water quality, fish responses to suspended sediment and farm income within two small watersheds, one of a cool water stream and one of a warm water stream. Using the Agricultural Drainage and Pesticide Transport (ADAPT) model, this study related best management practices (BMPs) to calculated instream suspended sediment concentrations by estimating sediment delivery, runoff, base flow, and streambank erosion to quantify the effects of suspended sediment exposure on fish communities. By implementing selected BMPs in each watershed, annual net farm income declined $18,000 to $28,000 (1 to 3 percent) from previous levels. "Lethal" fish events from suspended sediments in the cool water watershed decreased by 60 percent as conservation tillage and riparian buffers increased. Despite reducing suspended sediments by 25 percent, BMPs in the warm water watershed did not reduce the negative response of the fisheries. Differences in responses (physical and biological) between watersheds highlight potential gains in economic efficiency by targeting BMPs or by offering performance based "green payments." (JAWRA) (Copyright ?? 2005).

  15. Direct and indirect evidence of size-selective grazing on pelagic bacteria by freshwater nanoflagellates.

    Science.gov (United States)

    Simek, K; Chrzanowski, T H

    1992-11-01

    Size-selective grazing of three heterotrophic nanoflagellates (with cell sizes of 21, 44, and 66 mum) isolated from Lake Arlington, Texas was examined by using a natural mixture of fluorescence labelled lake bacteria. Sizes of ingested bacteria in food vacuoles were directly measured. Larger bacterial cells were ingested at a frequency much higher than that at which they occurred in the assemblage, indicating preferential flagellate grazing on the larger size classes within the lake bacterioplankton. Water samples were collected biweekly from June through September, 1989, fractionated by filtration, and incubated for 40 h at in situ temperatures. The average bacterial size was always larger in water which was passed through 1-mum-pore-size filters (1-mum-filtered water) (which was predator free) than in 5-mum-filtered water (which contained flagellates only) or in unfiltered water (in which all bacterivores were present). The increase of bacterial-cell size in 1-mum-filtered water was caused by a shift in the size structure of the bacterioplankton population. Larger cells became more abundant in the absence of flagellate grazing.

  16. Effect of Nickel on Some Aspects of Protein Metabolism in Selected Organs of the Freshwater of the Freshwater Mussel Lamellidens marginalis

    Institute of Scientific and Technical Information of China (English)

    P.SREEDEVI; B.SIVARAMAKRISHAN; 等

    1992-01-01

    The levels of soluble,structural and total proteins,and the activities of AlAT and AAT decreased along with an increase in the levels of free amino acids and the activity of protease in the ctenidium,hepatopancreas and foot of the freshwater mussel L.marginalis after 1,2,3,and 4d of exposure to a lethal concentration(115mg·L-1) of nickel.But the activity of GDH and the evel of urea decreased in the hepatopancreas and increased in the ctenidium and foot.A reverse trend was observed in the level of ammonia.In a sublethal concentration(23mg·L-1), the levels of soluble,structural and total proteins and ammonia decreased in these three organs of the mussel after,1,5,10and 15d of exposures,with an increase in the levels,of free aminoacids,urea and in the activities of protease,AlAT,AAT and GDH.The extent of these changes differed in degree depending on exposure period in the lethal and sublethal concentrations.The results are discussed in order to arrive at the degree of metal stress on the overall nitrogen metabolism of the mussel according to the period of exposure to lethal and sublethal concentrations of nickel.

  17. Growth responses of selected freshwater algae to trace elements and scrubber ash slurry generated by coal-fired power plants

    Energy Technology Data Exchange (ETDEWEB)

    Vocke, R.W.

    1979-01-01

    The development and implementation of standard toxicity tests is a necessity if consistent and reliable data are to be obtained for water quality criteria. The adapted EPA AAPBT is an ideal static algal toxicity test system. The algal test medium has a chemical composition similar to natural unpolluted waters of low ionic strength. It is appropriate to use MATC water quality criteria when assessing the potential impact of pollutants generated by coal-fired power stations because these energy-generated pollutants typically enter aquatic systems in small quantities over long periods. The MATC water quality criteria are estimates of trace element and SASE levels, based on the most sensitive alga investigated, that will not cause significant changes in naturally-functioning algal populations. These levels are 0.016f mg L/sup -1/ As(V), 0.001 mg L/sup -1/ Cd(II), 0.004 mg L/sup -1/ Hg(II), 0.006 mg L/sup -1/ Se(VI), and 0.344% SASE. To provide viable working water quality criteria, an extrapolation from the laboratory to the natural environment must be made. Therefore, those oxidation states of the trace elements were selected which are the dominant states occurring in natural, unpolluted, slightly alkaline freshwaters. It must be pointed out that these MATC values are based on algal responses to single toxicants and no allowance is made for synergistic, additive, or antagonistic relationships which could occur in natural aquatic systems. Additionally, natural chelation may influence toxicity. The highly toxic nature of potential pollutants from coal-fired generating plants emphasizes the need for minimizing stack effluent pollutants and retaining scrubber ash slurry for proper disposal in an effort to maintain trace elements in concentration ranges compatible with naturally-functioning ecosystems.

  18. Pyritization in the Gaojiashan Biota

    Institute of Scientific and Technical Information of China (English)

    CAI YaoPing; HUA Hong

    2007-01-01

    The Late Sinian (Ediacaran) Gaojiashan Biota was a soft-bodied fossil-Lagerst(a)tte dominated by substantial pyritized, three-dimensionally preserved tubular and conotubular fossils. Soft-tissue pyritization is extremely scarce in the fossil records, especially in the Precambrian, therefore it has very important and unique significance for the study of pyritization in the Gaojiashan Biota. Early pyritization played a pivotal role in the fossil preservation and two main factors ensured the successful pyritization of the fossils, namely rapid burial and permineralization. The former was controlled by secular storm deposition, and the latter was achieved by sufficient supply of available iron from sediments. SEM data of Conotubus demonstrate two types of preservation of the tubes (defined as type A and type B, respectively). In type A, pyritization took place relatively earlier and completely preserved both tube wall and coelom, but no detailed structure. While in type B, pyritization took place somewhat later and preserved the integrated tube wall, but partially the coelom. The size frequency distribution of the pyrite framboids suggests that pyritization took place in two different environments with entire different oxygen content.

  19. Bioaccumulation and depuration of chromium in the selected organs and whole body tissues of freshwater fish Cirrhinus mrigala individually and in binary solutions with nickel

    Institute of Scientific and Technical Information of China (English)

    PL. RM. Palaniappan; S. Karthikeyan

    2009-01-01

    Contamination of aquatic ecosystems with heavy metals has been receiving increased worldwide attention due to their harmful effects on human health and other organisms in the environment.Most of the studies dealing with toxic effects of metals deal with single metal species, while the aquatic organisms are typically exposed to mixtures of metals.Hence, in order to provide data supporting the usefulness of freshwater fish as indicators of heavy metal pollution, it has been proposed in the present study to investigate the bioaccumulation and depuration of chromium in the selected organs of freshwater fingerlings Cirrhinus mrigala, individually and in binary solutions with nickel.The results show that the kidney is a target organ for chromium accumulation, which implies that it is also the "critical" organ for toxic symptoms.The results further show that accumulation of nickel in all the tissues of C.mrigala is higher than that of chromium.In addition, the metal accumulations of the binary mixtures of chromium and nickel are substantially higher than those of the individual metals, indicating synergistic interactions between the two metals.Theoretically the simplest explanation for an additive joint action of toxicants in a mixture is that they act in a qualitatively similar way.The observed data suggest that C.mrigala could be suitable monitoring organisms to study the bioavailability of water-bound metals in freshwater habitats.

  20. Length weight relationship and condition factor of selected freshwater fish species found in river Ganga, Gomti and Rapti, India.

    Science.gov (United States)

    Sarkar, U K; Khan, G E; Dabas, A; Pathak, A K; Mir, J I; Rebello, S C; Pal, A; Singh, S P

    2013-09-01

    This study is based on the length-weight relationships (LWRs) of 2148 fishes, belonging to 8 families, 12 genera and 15 freshwater fish species (Wallago attu, Rite rita, Sperato seenghala, Sperota aor, Mostacembalus armatus, Macrognathus puncolus, Gudusia chopra, Clupisoma garua, Puntius sophore, Puntius ticto, Rasbora daniconius, Amblypharyngodon mole, Chanda noma, Colisa fociatus and Colisa sota) captured from river Ganga, Gomti and Rapti during May 2011 to March 2012. The growth coefficient (b) values varied between 1.30 and 3.07, with the mean b = 2.03 at priver basin. The objective was to evaluate the pattern of LWRs and condition factors of the freshwater fish species of the main Ganga and tributaries which serves as baseline for other tropical Indian rivers and tributaries.

  1. Length weight relationship and condition factor of selected freshwater fish species found in river Ganga, Gomti and Rapti, India.

    Science.gov (United States)

    Sarkar, U K; Khan, G E; Dabas, A; Pathak, A K; Mir, J I; Rebello, S C; Pal, A; Singh, S P

    2013-09-01

    This study is based on the length-weight relationships (LWRs) of 2148 fishes, belonging to 8 families, 12 genera and 15 freshwater fish species (Wallago attu, Rite rita, Sperato seenghala, Sperota aor, Mostacembalus armatus, Macrognathus puncolus, Gudusia chopra, Clupisoma garua, Puntius sophore, Puntius ticto, Rasbora daniconius, Amblypharyngodon mole, Chanda noma, Colisa fociatus and Colisa sota) captured from river Ganga, Gomti and Rapti during May 2011 to March 2012. The growth coefficient (b) values varied between 1.30 and 3.07, with the mean b = 2.03 at priver basin. The objective was to evaluate the pattern of LWRs and condition factors of the freshwater fish species of the main Ganga and tributaries which serves as baseline for other tropical Indian rivers and tributaries. PMID:24558811

  2. Proposed Release Guides to Protect Aquatic Biota

    Energy Technology Data Exchange (ETDEWEB)

    Marter, W.L.

    2001-03-28

    At the request of South Carolina Department of Health and Environmental Control (SCDHEC) and the Department of Energy (DOE), the Savannah River Laboratory was assigned the task of developing the release guides to protect aquatic biota. A review of aquatic radioecology literature by two leading experts in the field of radioecology concludes that exposure of aquatic biota at one rad per day or less will not produce detectable deleterious effects on aquatic organisms. On the basis of this report, DOE recommends the use of one rad per day as an interim dose standard to protect aquatic biota.

  3. Freshwater Wetlands.

    Science.gov (United States)

    Naturescope, 1986

    1986-01-01

    Provides descriptions about freshwater wetlands, such as marshes, swamps, and bogs. Contains three learning activities which deal with unusual wetland plants, the animals and plants in a typical marsh, and the effects of a draught on a swamp. Included are reproducible handouts and worksheets for two of the activities. (TW)

  4. Comparative analysis of doses to aquatic biota in water bodies impacted by radioactive contamination

    International Nuclear Information System (INIS)

    Comparative analysis of doses to the reference species of freshwater biota was performed for the following water bodies in Russia or former USSR: Chernobyl NPPs cooling pond, Lakes Uruskul and Berdenish located in the Eastern Urals Radioactive Trace, Techa River, Yenisei River. It was concluded that the doses to biota were considerably different in the acute and chronic periods of radioactive contamination. The most vulnerable part of all considered aquatic ecosystems was benthic trophic chain. A numerical scale on the “dose rate – effects” relationships for fish was formulated. Threshold dose rates above which radiation effects can be expected in fish were evaluated to be the following: 1 mGy d−1 for appearance of the first morbidity effects in fish; 5 mGy d−1 for the first negative effects on reproduction system; 10 mGy d−1 for the first effects on life shortening of fish. The results of dose assessment to biota were compared with the scale “dose rate – effects” and the literature data on the radiobiological effects observed in the considered water bodies. It was shown that in the most contaminated water bodies the dose rates were high enough to cause the radiobiological effects in fish. - Highlights: ► Comparative analysis of dose rates to biota in different water bodies was performed. ► A numerical scale on the dose rates – effects relationships for fish was formulated. ► Results of assessment of exposure to biota were compared with the dose rates – effects scale. ► In the most contaminated water bodies the doses were high enough to cause radiobiological effects in fish. ► Current dose rates to biota in all considered water bodies are below the safety level of 1 mGy/day.

  5. Part 7: Monitoring of biota

    International Nuclear Information System (INIS)

    The present state of the biota, in respect to the previous state and in respect to the development after the realised technical measures on both sides, was evaluated according to the data included in the Slovak-Hungarian joint monitoring covering the period from 1992 to 1996. The river branch water supply on the Slovak side was introduced in May 1993 through the intake structure at Dobrohost. On the Hungarian side the water supply is accomplished by the underwater weir put into operation in June 1995. The biological monitoring on the Slovak side was performed at six monitoring areas, where all the groups agreed in the joint monitoring were monitored. On the Hungarian side each group were monitored on different monitoring sites. The water supply introduced on the Hungarian side by the underwater weir operation has no impact on the Slovak side. Similar impact as it is now observed on the Hungarian side has been observed on the Slovak side since introduction of water supply in 1993. The increased amount of water discharged to the Danube was reflected by changes of the habitat of aquatic communities. The water supply on the Hungarian side was accomplished by the construction of the underwater weir and therefore a connection of the river branch system with the Danube at two factors have had very significant influence on the bio-tops existing in the river branch system and subsequently to the fauna and flora. Generally large amount of water became available, which was reflected in change of stagnant or slowly flowing water into water flow with higher velocity or in increase of the water surface. In some locations the water level returned to the state before damming, in others new bio-tops were created, and in some locations the previous bio-tops disappeared. To these changed conditions the aquatic fauna reacted the most rapidly.The terrestrial communities prove the necessity of flooding and raising of ground water level on some of the inundation areas, because in spite

  6. A freshwater biodiversity hotspot under pressure – assessing threats and identifying conservation needs for ancient Lake Ohrid

    OpenAIRE

    G. Kostoski; Albrecht, C.; S. Trajanovski; Wilke, T.

    2010-01-01

    Freshwater habitats and species living in freshwater are generally more prone to extinction than terrestrial or marine ones. Immediate conservation measures for world-wide freshwater resources are thus of eminent importance. This is particularly true for so called ancient lakes. While these lakes are famous for being evolutionary theatres, often displaying an extraordinarily high degree of biodiversity and endemism, in many cases these biota are also experiencing extreme anthropogenic impact....

  7. Freshwater fish of the Wilderness National Park

    Directory of Open Access Journals (Sweden)

    I.A. Russell

    1999-01-01

    Full Text Available The study aimed to determine the distribution and relative abundance of freshwater fish in the Wilderness National Park. Fish assemblages in the Touw and Duiwe rivers were sampled in 1997 and 1998, with a total of 327 fish from nine species recorded. Indigenous species included two freshwater species (Pseudobarbus afer, Sandelia capensis, two catadromous species (Anguilla mossambicus, Myxus capensis, and two estuarine species (Monodactylusfalciformis, Caffrogobius multifasciatus. Three of the nine recorded species were alien (Micropterus dolomieu, Micropterus salmoides, Gambusia affinis, with the Micropterus spp., in particular, likely to have a substantial negative influence on indigenous species. A further one indigenous species, two translocated indigenous species, and five estuarine species could potentially be recorded in these rivers. River catchment management actions to restore perennial flow to the Duiwe River, to prevent the attenuation of floods, and to prevent further establishment and spread of alien and translocated biota are required to conserve indigenous fish assemblages.

  8. Biota - Elwha River salmon carcass addition experiment

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Dam removal and other fish-barrier removal projects in western North America are assumed to boost freshwater productivity via the transport of marine-derived...

  9. Combined ecological risks of nitrogen and phosphorus in European freshwaters

    OpenAIRE

    Azevedo, L.B.; van Zelm, R.; Leuven, R. S. E. W; Hendriks, A. J; Huijbregts, M.A.J.

    2015-01-01

    Eutrophication is a key water quality issue triggered by increasing nitrogen (N) and phosphorus (P) levels and potentially posing risks to freshwater biota. We predicted the probability that an invertebrate species within a community assemblage becomes absent due to nutrient stress as the ecological risk (ER) for European lakes and streams subjected to N and P pollution from 1985 to 2011. The ER was calculated as a function of species-specific tolerances to NO3 - and total P concentrations a...

  10. Selective inhibition of toxic cyanobacteria by β-carboline-containing bacterium Bacillus flexus isolated from Saudi freshwaters.

    Science.gov (United States)

    Alamri, Saad A; Mohamed, Zakaria A

    2013-10-01

    A bacterial strain SSZ01 isolated from a eutrophic lake in Saudi Arabia dominated by cyanobacterial blooms, showed an antialgal activity against cyanobacteria species. Based on the analysis of the 16S rDNA gene sequence, the isolated strain (SSZ01) most likely belonged to the genus Bacillus with a 99% similarity to Bacillus flexus strain EMGA5. The thin layer chromatography (TLC) analysis of the ethyl acetate extract of this bacterium revealed that this strain can produce harmine and norharmane compared to different β-carboline analog standards. Harmine and norharmane were also detected in considerable amounts in bacterial growth medium, indicating a potential excretion of these compounds into the aquatic environment. The crude extract of Bacillus flexus as well as pure materials of harmine and norharmane inhibited the growth of tested species of cyanobacteria. However, the bacterial crude extract has a higher toxicity against tested species of cyanobacteria than harmine and norharmane. In addition, harmine was more toxic to cyanobacteria than norharmane. On the other hand, neither pure compounds of harmine and norharmane nor crude bacterial extract showed any antialgal activity against tested species of green algae. The results of the present study suggest that B. flexus SSZ01 or its crude extract containing harmine and norharmane could be a candidate for the selective control of cyanobacterial blooms without affecting other algal species. PMID:24235872

  11. Solid-phase/supercritical-fluid extraction for liquid chromatography of phenolic compounds in freshwater microalgae and selected cyanobacterial species.

    Science.gov (United States)

    Klejdus, B; Kopecký, J; Benesová, L; Vacek, J

    2009-01-30

    In the present paper a new extraction technique based on the combination of solid-phase/supercritical-fluid extraction (SPE/SFE) with subsequent reversed-phase HPLC is described. The SPE/SFE extractor was originally constructed from SPE-cartridge incorporated into the SFE extraction cell. Selected groups of benzoic acid derivatives (p-hydroxybenzoic, protocatechuic, gallic, vanillic and syringic acid), hydroxybenzaldehydes (4-hydroxybenzaldehyde and 3,4-dihydroxybenzaldehyde) and cinnamic acid derivatives (o-coumaric, p-coumaric, caffeic, ferulic, sinapic and chlorogenic acid) were extracted. Cyclic addition of binary extraction solvent system based on methanol:water (1:1, v/v) and methanol/ammonia aqueous solution was used for extraction at 40MPa and 80 degrees C. The p-hydroxybenzoic, protocatechuic, vanillic, syringic, caffeic and chlorogenic acid; 4-hydroxybenzaldehyde and 3,4-dihydroxybenzaldehyde were identified by HPLC-electrospray mass spectrometry in SPE/SFE extracts of acid hydrolyzates of microalga (Spongiochloris spongiosa) and cyanobacterial strains (Spirulina platensis, Anabaena doliolum, Nostoc sp., and Cylindrospermum sp.). For the identification and quantification of the compounds the quasi-molecular ions [M-H](-) and specific fragments were analysed by quadrupole mass spectrometry analyzer. Our analysis showed that the microalgae and cyanobacteria usually contained phenolic acids or aldehydes at microg levels per gram of lyophilized sample. The proposed SPE/SFE extraction method would be useful for the analysis of different plant species containing trace amount of polar fraction of phenols. PMID:19111311

  12. Spatial distribution and partitioning behavior of selected poly- and perfluoroalkyl substances in freshwater ecosystems: A French nationwide survey

    International Nuclear Information System (INIS)

    The spatial distribution and partitioning of 22 poly- and perfluoroalkyl substances (PFASs) in 133 selected rivers and lakes were investigated at a nationwide scale in mainland France. ΣPFASs was in the range < LOD–725 ng L−1 in the dissolved phase (median: 7.9 ng L−1) and < LOD–25 ng g−1 dry weight (dw) in the sediment (median: 0.48 ng g−1 dw); dissolved PFAS levels were significantly lower at “reference” sites than at urban, rural or industrial sites. Although perfluorooctane sulfonate (PFOS) was found to be the prevalent compound on average, a multivariate analysis based on neural networks revealed noteworthy trends for other compounds at specific locations and, in some cases, at watershed scale. For instance, several sites along the Rhône River displayed a peculiar PFAS signature, perfluoroalkyl carboxylates (PFCAs) often dominating the PFAS profile (e.g., PFCAs > 99% of ΣPFASs in the sediment, likely as a consequence of industrial point source discharge). Several treatments for data below detection limits (non-detects) were used to compute descriptive statistics, differences among groups, and correlations between congeners, as well as log Kd and log Koc partition coefficients; in that respect, the Regression on Order Statistics (robust ROS) method was preferred for descriptive statistics computation while the Akritas–Theil–Sen estimator was used for regression and correlation analyses. Multiple regression results suggest that PFAS levels in the dissolved phase and sediment characteristics (organic carbon fraction and grain size) may be significant controlling factors of PFAS levels in the sediment. - Highlights: • A large-scale survey of PFASs in 133 French rivers and lakes is reported. • Descriptive statistics, correlations and partitioning coefficients were determined. • Non-detects were taken into account using functions from the NADA R-package. • Hot spots of PFAS contamination were found near large urban and industrial areas

  13. Application of biota dose assessment tools for Japan environment

    International Nuclear Information System (INIS)

    We examined applicability of two biota assessment tools RESRAD-BIOTA and ERICA assessment tool, to Japanese environment. We considered paddy field as the typical Japan environment and used maximum of global fallout nuclide concentrations. The case studies showed that graded approaches used in RESRAD-BIOTA and ERICA assessment tool are effective to apply Japanese environment. In addition, we concluded that it is important to clarify the suitability of some parameter values used in biota dose assessment. Further study is necessary on the recommendation of environmental parameter values for biota dose assessment for Japan environment. (author)

  14. Spatial distribution and partitioning behavior of selected poly- and perfluoroalkyl substances in freshwater ecosystems: A French nationwide survey

    Energy Technology Data Exchange (ETDEWEB)

    Munoz, Gabriel; Giraudel, Jean-Luc [University of Bordeaux, EPOC, UMR 5805, LPTC, 351 Cours de la Libération, F-33400 Talence, France. (France); Botta, Fabrizio; Lestremau, François [INERIS, Parc Technologique Alata, BP2, 60550 Verneuil-en-Halatte, France. (France); Dévier, Marie-Hélène [University of Bordeaux, EPOC, UMR 5805, LPTC, 351 Cours de la Libération, F-33400 Talence, France. (France); Budzinski, Hélène [CNRS, EPOC, UMR 5805, LPTC, 351 Cours de la Libération, F-33400 Talence, France. (France); Labadie, Pierre, E-mail: pierre.labadie@u-bordeaux.fr [CNRS, EPOC, UMR 5805, LPTC, 351 Cours de la Libération, F-33400 Talence, France. (France)

    2015-06-01

    The spatial distribution and partitioning of 22 poly- and perfluoroalkyl substances (PFASs) in 133 selected rivers and lakes were investigated at a nationwide scale in mainland France. ΣPFASs was in the range < LOD–725 ng L{sup −1} in the dissolved phase (median: 7.9 ng L{sup −1}) and < LOD–25 ng g{sup −1} dry weight (dw) in the sediment (median: 0.48 ng g{sup −1} dw); dissolved PFAS levels were significantly lower at “reference” sites than at urban, rural or industrial sites. Although perfluorooctane sulfonate (PFOS) was found to be the prevalent compound on average, a multivariate analysis based on neural networks revealed noteworthy trends for other compounds at specific locations and, in some cases, at watershed scale. For instance, several sites along the Rhône River displayed a peculiar PFAS signature, perfluoroalkyl carboxylates (PFCAs) often dominating the PFAS profile (e.g., PFCAs > 99% of ΣPFASs in the sediment, likely as a consequence of industrial point source discharge). Several treatments for data below detection limits (non-detects) were used to compute descriptive statistics, differences among groups, and correlations between congeners, as well as log K{sub d} and log K{sub oc} partition coefficients; in that respect, the Regression on Order Statistics (robust ROS) method was preferred for descriptive statistics computation while the Akritas–Theil–Sen estimator was used for regression and correlation analyses. Multiple regression results suggest that PFAS levels in the dissolved phase and sediment characteristics (organic carbon fraction and grain size) may be significant controlling factors of PFAS levels in the sediment. - Highlights: • A large-scale survey of PFASs in 133 French rivers and lakes is reported. • Descriptive statistics, correlations and partitioning coefficients were determined. • Non-detects were taken into account using functions from the NADA R-package. • Hot spots of PFAS contamination were found

  15. Preliminary Study on Coral Reef and Its Associated Biota in Qatari Waters, Arabian Gulf

    OpenAIRE

    Al Ansi, Mohsin A. [محسن عبد الله العنسي; AL-KHAYAT, Jassim A.

    1999-01-01

    Coral reef grounds and their associated biota m Qatari waters were investigated by Scuba diving. Four selected reef-sites were studied. Coral was presented by 17 species. Descriptive notes of each site and an initial list of associated fauna and flora were presented. The associated biota composed mainly of Algae 23 sp, Porifera 5 sp, Bryozoa 4 sp, Polychaeta 17 sp, Echinodermata 21 sp, Mollusca 102 sp, Chordata 4 sp, and Crustacea 15 sp. Mollusca was the predominant group in all visited sites...

  16. Redistribution of soil biota by rainfall erosion

    Science.gov (United States)

    Baxter, Craig; Rowan, John; McKenzie, Blair; Neilson, Roy

    2013-04-01

    Soil is central to the provision of multiple ecosystem services that sustain life through a myriad of chemical, physical and biological processes. One of the greatest threats to soil is erosion, a natural process accelerated by human activities. Elevated erosion rates are common in agro-ecosystems causing both direct physical impacts (e.g. soil loss), and indirect biogeochemical consequences, which ultimately leads to impaired ecosystem functioning. The consequences of erosion on soil biota have hitherto been ignored, yet biota have fundamental roles in the provision of soil ecosystem services. To our knowledge few studies have addressed the gap between erosion and impacts on soil biota. Here we use soil nematodes as a model organism for assessing erosion impacts on soil (micro) fauna in temperate agro-ecosystems. Soil nematodes are ubiquitous, abundant, are represented at all levels in soil food webs and can be categorised into a range of trophic or functional groups. To quantify transport of nematodes and gain a better understanding of erosive mechanisms responsible, we measured their export from small erosion plots (0.0625m2) under a fixed-intensity design rainstorm (6mm min-1 duration: 3 min) over six slope angles (4° - 24°) and three soil texture classes (sandy silt, silty sand, silt). Runoff and eroded sediment were collected for each plot (four replicate runs), and a suite of biological and physico-chemical parameters measured. Results confirmed that, similar to soil particles, nematodes were exported at rates influenced by slope angle and soil texture. These experiments, linked with field and catchment-scale equivalents, are designed to elucidate the links between soil erosion and provision of ecosystem services and to inform biodiversity-sensitive soil and water conservation practices.

  17. Biota-sediment accumulation factors for radionuclides and sediment associated biota of the Ottawa River

    Energy Technology Data Exchange (ETDEWEB)

    Rowan, D.; Silke, R.; Carr, J., E-mail: rowand@aecl.ca [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)

    2013-12-15

    As Ottawa River contamination is historical and resides in sediment, ecological risk and trophic transfer depend on linkages between sediment and biota. One of the ways in which this linkage is quantified is through the use of the biota sediment accumulation factor (BSAF). In this study, we present the first field estimates of BSAF for a number of radionuclides. The strongest and most consistent BSAFs were those for {sup 137}Cs in deposit feeding taxa, suggesting that sediment concentrations rather than dissolved concentrations drive uptake. For crayfish and unionid bivalves that do not feed on sediment, biota radionuclide concentrations were not related to sediment concentrations, but rather reflected concentrations in water. BSAFs would not be appropriate for these non-deposit feeding biota. BSAFs for {sup 137}Cs were not significantly different among deposit feeding taxa, suggesting similar processes for ingestion, assimilation and elimination. These data also show that the concentration factor approach used for guidance would have led to spurious results in this study for deposit feeding benthic invertebrates. Concentrations of {sup 137}Cs in Hexagenia downstream of the CRL process outfall range by about 2-orders of magnitude, in comparison to relatively uniform water concentrations. The concentration factor approach would have predicted a single value downstream of CRL, underestimating exposure to Hexagenia by almost 2-orders of magnitude at sites close to the CRL process outfall. (author)

  18. Bangladesh Sundarbans: Present status of the environment and Biota

    Directory of Open Access Journals (Sweden)

    Abdul Aziz

    2015-07-01

    Full Text Available The Sundarbans is a deltaic mangrove forest, formed about 7000 years ago by the deposition of sediments from the foothills of the Himalayas through the Ganges river system, and is situated southwest of Bangladesh and south of West Bengal, India. However, for the last 40 years, the discharge of sediment-laden freshwater into the Bay of Bengal through the Bangladesh part of the Sundarbans Mangrove Forests (BSMF has been reduced due to a withdrawal of water during the dry period from the Farakka Barrage in India. The result is two extremes of freshwater discharge at Gorai, the feeding River of the BSMF: a mean minimum monthly discharge varies from 0.00 to 170 m3·s−1 during the dry period with a mean maximum of about 4000 to 8880 m3·s−1 during the wet period. In the BSMF, about 180 km downstream, an additional low discharge results in the creation of a polyhaline environment (a minimum of 194.4 m3·s−1 freshwater discharge is needed to maintain an oligohaline condition during the dry period. The Ganges water carries 262 million ton sediments/year and only 7% is diverted in to southern distributaries. The low discharge retards sediment deposition in the forestlands’ base as well as the formation of forestlands. The increase in water flow during monsoon on some occasions results in erosion of the fragile forestlands. Landsat Satellite data from the 1970s to 2000s revealed a non-significant decrease in the forestlands of total Sundarbans by 1.1% which for the 6017 km2 BSMF is equivalent to 66 km2. In another report from around the same time, the estimated total forestland loss was approximately 127 km2. The Sundarbans has had great influence on local freshwater environments, facilitating profuse growth of Heritiera fomes (sundri, the tallest (at over 15 m and most commercially important plant, but now has more polyhaline areas threatening the sundri, affecting growth and distribution of other mangroves and biota. Landsat images and GIS data

  19. Deriving Freshwater Quality Criteria for Iron, Lead, Nickel, and Zinc for Protection of Aquatic Life in Malaysia

    OpenAIRE

    Shuhaimi-Othman, M.; Y. Nadzifah; Nur-Amalina, R.; Umirah, N. S.

    2012-01-01

    Freshwater quality criteria for iron (Fe), lead (Pb), nickel (Ni), and zinc (Zn) were developed with particular reference to aquatic biota in Malaysia, and based on USEPA's guidelines. Acute toxicity tests were performed on eight different freshwater domestic species in Malaysia which were Macrobrachium lanchesteri (prawn), two fish: Poecilia reticulata and Rasbora sumatrana, Melanoides tuberculata (snail), Stenocypris major (ostracod), Chironomus javanus (midge larvae), Nais elinguis (anneli...

  20. Scoping assessment of groundwater doses to biota at the Sellafield site, UK

    International Nuclear Information System (INIS)

    In the current climate of investigating the impact of discharges from the nuclear industry on non-human biota, much attention has been given to biota in marine and terrestrial environments in receipt of authorised discharges of liquid and gaseous effluent. Relatively little attention to date has been given to the exposure of biota to groundwater containing man-made radio-nuclides. This area of interest is growing especially in the field of nuclear waste repositories. A scoping assessment has been performed here to determine the impacts due to radiological contamination on organisms living within or coming into contact with groundwater at the Sellafield site, UK. The following potential exposure routes to biota were identified: 1) Organisms living within groundwater; 2) Groundwater discharges to the surface at beach springs (i.e. emerging above the low water line; 3) Groundwater discharges to nearby surface water bodies (e.g. rivers); 4) Groundwater discharges directly to the Irish Sea.. In order to evaluate impacts on organisms living within, contacting or ingesting groundwater, it was necessary to determine the activity concentration of radio-nuclides in the groundwater. For time periods up to 2120, modeling of contaminant release from in-ground inventories and transport in groundwater was carried out for this scoping study using a relatively simple assessment methodology with the MONDRIAN modeling suite. Screening assessments of radiological impacts upon wildlife have been performed for liquid discharges to groundwater from the Sellafield Ltd reprocessing plant at Sellafield, Cumbria. Impacts have been considered for biota at sites within reach of the groundwater flow network. Most calculated total weighted absorbed doses appear to be of no radiological significance whatsoever in relation to the new Environment Agency freshwater ecosystem trigger level (40 microGy h-1), thereby obviating the need to conduct further investigations. The one exception to this is for

  1. Decline of radionuclides in Columbia River biota

    International Nuclear Information System (INIS)

    In January 1971, the last of nine plutonium production reactors using direct discharge of once-through cooling waters into the Columbia River was closed. Sampling was initiated at three stations on the Columbia River to document the decline of the radionuclide body burdens in the biota of the Columbia River ecosystem. The data show that in a river-reservoir complex, the measurable body burden of fission-produced radionuclides decreased to essentially undetectable levels within 18 to 24 mo after cessation of discharge of once-through cooling water into the river. On the basis of data from the free-flowing station, we believe that this decrease would be even more rapid in an unimpounded river

  2. The uptake of radiationless by some fresh water aquatic biota review

    International Nuclear Information System (INIS)

    The work presented in this paper reviews many studies carried out by the authors along the last thirty years. The behaviour of the radionuclides in the aquatic ecology of Ismailia Canal stream is of great interest for the evaluation of the possible hazards that may occur to man through the movement of such radionuclides via food chain. Laboratory investigations have been carried out in order to understand the accumulation and release of some radionuclide by some aquatic biota (aquatic macrophyte aquatic plants, some snails species and some fish species) inhabiting this fresh water stream. Different parameters such as water ph, contact time, water salinity, etc. were used in these investigations. The kinetic analysis of the uptake process of some radio nuclides by certain biota was performed. From this analysis, it was possible (through the statistical methods) to investigate that the uptake process proceeded through different steps with different rates depending on the radionuclide and the biota species. It was possible to conclude that some of the selected biota can be used as biological indicators for certain radionuclides

  3. Water hardness reduces the accumulation and toxicity of uranium in a freshwater macrophyte (Ceratophyllum demersum).

    Science.gov (United States)

    Markich, Scott J

    2013-01-15

    previous work) reinforce the need for a more flexible, hardness-dependent, U guideline for the protection of selected freshwater biota.

  4. ACCUMULATION OF HEAVY METALS IN BIOTA OF VYRLYTSA LAKE

    OpenAIRE

    Bilyk, Tetiana; Tsurkan, Katerina; Koren, Lyudmila

    2011-01-01

    Abstract. The main task was to investigate the pollution by heavy metals of biota of Vyrlytsa Lake. Thecontents of movable forms of heavy metals in aquatic plants, fish and snails was determined by atomicabsorbtion method and were made the conclusions about general state of the water object.Keywords: heavy metals, accumulation, biota, pollution, atomic absorption spectroscopy.

  5. A Miocene perspective on the evolution of the Amazonian biota

    NARCIS (Netherlands)

    Wesselingh, F.P.; Salo, J.A.

    2006-01-01

    Between c. 23 and 8 Ma, western Amazonia was occupied by the vast Pebas long-lived lake/wetland system. The Pebas system had a variety of influences over the evolution of Miocene and modern Amazonian biota; it formed a barrier for the exchange of terrestrial biota, a pathway for the transition of ma

  6. Ecosystem services of soil biota: In what context is a focus on soil biota meaningful?

    Science.gov (United States)

    Baveye, Philippe C.

    2016-04-01

    Over the last few years, the topic of the ecosystem services of soils has attracted considerable attention, in particular among researchers working on soil biota. A direct link is established explicitly in numerous articles between soil biota and specific ecosystem services, or between soil biodiversity and ecosystem services. A careful review of the literature indicates however that these links are, more often than not, strictly axiomatic, rather than based on actual observations. In fact, there are still at the moment virtually no measurements of ecosystem services of soils at any scale, measurements that would be required to establish such links. Furthermore, at a conceptual level, it is not clear to what extent the effect of soil biota in the delivery of ecosystem services can be separated from the contribution of other components of soil systems. Soil microorganisms, in particular, proliferate and are metabolically active in a pore space whose characteristics and dynamics could in principle have a profound effect on their activity. So also could the composition and spatial distribution of soil organic matter, or the spatial pattern of plant root propagation. By emphasizing the role of soil biota, at the exclusion of other aspects of soil systems, there is a risk that important features of the provision of ecosystem services by soils will be missed. In this talk (based in part on a workshop organized recently in France, and of a follow-up review article), an analysis of this general problem will be presented, as well as suggestions of how to avoid it by promoting truly interdisciplinary research involving not only soil ecologists but also physicists, hydrologists, and chemists.

  7. Concentration of 129I in aquatic biota collected from a lake adjacent to the spent nuclear fuel reprocessing plant in Rokkasho, Japan

    International Nuclear Information System (INIS)

    The spent nuclear fuel reprocessing plant in Rokkasho, Japan, has been undergoing final testing since March 2006. During April 2006-October 2008, that spent fuel was cut and chemically processed, the plant discharged 129I into the atmosphere and coastal waters. To study 129I behaviour in brackish Lake Obuchi, which is adjacent to the plant, 129I concentrations in aquatic biota were measured by accelerator mass spectrometry. Owing to 129I discharge from the plant, the 129I concentration in the biota started to rise from the background concentration in 2006 and was high during 2007-08. The 129I concentration has been rapidly decreasing after the fuel cutting and chemically processing were finished. The 129I concentration factors in the biota were higher than those reported by IAEA for marine organisms and similar to those reported for freshwater biota. The estimated annual committed effective dose due to ingestion of foods with the maximum 129I concentration in the biota samples was 2.8 nSv y-1. (authors)

  8. Recent changes in aquatic biota in subarctic Fennoscandia - the role of global and local environmental variables

    Science.gov (United States)

    Weckström, Jan; Leppänen, Jaakko; Sorvari, Sanna; Kaukolehto, Marjut; Weckström, Kaarina; Korhola, Atte

    2013-04-01

    The Arctic, representing a fifth of the earth's surface, is highly sensitive to the predicted future warming and it has indeed been warming up faster than most other regions. This makes the region critically important and highlights the need to investigate the earliest signals of global warming and its impacts on the arctic and subarctic aquatic ecosystems and their biota. It has been demonstrated that many Arctic freshwater ecosystems have already experienced dramatic and unpreceded regime shifts during the last ca. 150 years, primarily driven by climate warming. However, despite the indisputable impact of climate-related variables on freshwater ecosystems other, especially local-scale catchment related variables (e.g. geology, vegetation, human activities) may override the climate signal and become the primary factor in shaping the structure of aquatic ecosystems. Although many studies have contributed to an improved understanding of limnological and hydrobiological features of Artic and subarctic lakes, much information is still needed especially on the interaction between the biotic and abiotic components, i.e. on factors controlling the food web dynamics in these sensitive aquatic ecosystems. This is of special importance as these lakes are of great value in water storage, flood prevention, and maintenance of biodiversity, in addition to which they are vital resources for settlement patterns, food production, recreation, and tourism. In this study we compare the pre-industrial sediment assemblages of primary producers (diatoms and Pediastrum) and primary consumers (cladoceran and chironomids) with their modern assemblages (a top-bottom approach) from 50 subarctic Fennoscandian lakes. We will evaluate the recent regional pattern of changes in aquatic assemblages, and assess how coherent the lakes' responses are across the subarctic area. Moreover, the impact of global (e.g. climate, precipitation) and local (e.g. lake and its catchment characteristics) scale

  9. Central Northwest Pacific biota and their radioactivity

    International Nuclear Information System (INIS)

    Ecological and radiological surveys of biota around a proposed dumping site have been carried out by the Japanese Fisheries Agency. Micronekton were collected with a KOC net towed at prescribed depths. Fish nekton were collected with a KMT net towed from 1 to 2 hours either obliquely or horizontally at prescribed depths. This large net enabled the collection of larger organisms not collectable with KOC nets. Benthos were collected via benthos nets. Deep sea rattails and gammarids were collected with trapnets. In 1985, larger gear with mouth diameters of 1.8m were used with older gear having mouth diameters of 0.9m and used previously. New large gear allowed better collecting efficiency. Radioactivity measurements were carried out by gammaspectrometry with GeLi detectors on ashed samples. In almost all samples, Cs-137 was detected. In addition Co-60 was detected in some samples. Data obtained by the Tokai Regional Fisheries Research Laboratory were examined and summarized by the Ecology Working Group under the Executive Committee on Environmental Safety Assessment of Sea Dumping of Low level Radioactive Wastes in the Radioactive Waste Management Center

  10. Dinomischus from the Middle Cambrian Kaili Biota, Guizhou, China

    Institute of Scientific and Technical Information of China (English)

    PENG Jin; ZHAO Yuanlong; LIN Jih-Pai

    2006-01-01

    Dinomischus is a rare solitary epifaunal suspension feeder. The over-all morphology of Dinomischus consists of a conical calyx surrounded with elongate bracts and an elongate stem. Visceral mass and stomach sac are evident in the body cavity. Dinomischus is interpreted as a primative ancestor of living entoprocts based on similarities in morphology and mode of life. Previously,Dinomischus is only known in two localities: the mid-Middle Cambrian Burgess Shale Biota and the Early Cambrian Chengjiang Biota. A single specimen of Dinomischus cf. D. isolatus Cowry Morris,1977 from the Kaili Biota, Guizhou, China is reported here. The discovery of Dinomischus in the Kaili Biota extends its geographical range and indicated that the rare Dinomischus could tolerate deeper water settings during the Middle Cambrian.

  11. The U.S. Department of Energy's graded approach for evaluating radiation doses to non-human biota

    International Nuclear Information System (INIS)

    The United States Department of Energy (DOE) has been active in developing requirements, methods, and guidance for protection of non-human biota from the effects of ionizing radiation since the late 1980's. Radiation protection of the environment is an emerging issue that will likely require attention in environmental monitoring programs, and in decisions regarding cleanup and long-term stewardship of radioactively-contaminated sites. The DOE currently has a radiation dose limit for protecting aquatic organisms, and has considered dose limits for terrestrial biota. Practical, cost-effective guidance for implementation of these dose rate guidelines are needed. In response, DOE has developed methods, models, and guidance within a graded approach for evaluating radiation doses to non-human biota. The methodology was developed using an interdisciplinary team approach that included both 'developers' and 'users' through DOE's Biota Dose Assessment Committee (BDAC). The first phase of the graded or multi-tiered approach consists of a general screening methodology that provides limiting concentrations of radionuclides, termed Biota Concentration Guides (BCGs), for use in screening water, sediment, and soil to determine if dose guidelines for non-human biota are exceeded. BCGs were derived for twenty-three target radionuclides. Four organism types (aquatic animals, riparian animals, terrestrial animals, and terrestrial plants) were selected as the basis for methods development. Internal doses were calculated as the product of media concentration, bioaccumulation factor(s), and dose conversion factors. External doses were calculated based on the assumption of immersion of the organism in soil, sediment, or water. Kinetic and allometric techniques were used to fill data gaps in predicting radionuclide concentration factors across a large range of terrestrial and riparian species of animals. The assumptions and default parameters result in conservative BCGs for screening

  12. The biology and functional morphology of Macoma biota (Bivalvia: Tellinidae: Macominae

    Directory of Open Access Journals (Sweden)

    Pedro Ribeiro Piffer

    2011-06-01

    Full Text Available Macoma biota Arruda & Domaneschi, 2005, is a recently described species known only from the intertidal zone of Praia da Cidade, Caraguatatuba Bay, in the state of São Paulo, southeastern Brazil. The main purpose of the present paper is to describe the biology of M. biota, beginning with a detailed analysis of its anatomy and functional morphology and how these attributes are correlated with its habitat and life history. The morphology of the organs in the pallial cavity and their sorting devices indicate that this species has efficient mechanisms to process large amounts of particles that enter this cavity via the inhalant current. M. biota can rapidly select the material suitable for ingestion and direct the undesired excess to the rejection mantle tracts. These characteristics along with the siphon's behavior and the digestive tract configuration reveal that this species can be classified primarily as a deposit feeder, like other species of the genus; however, it can also behave as a suspension feeder, depending on the environmental conditions.

  13. Establishing a database of radionuclide transfer parameters for freshwater wildlife

    International Nuclear Information System (INIS)

    Environmental assessments to evaluate potentials risks to humans and wildlife often involve modelling to predict contaminant exposure through key pathways. Such models require input of parameter values, including concentration ratios, to estimate contaminant concentrations in biota based on measurements or estimates of concentrations in environmental media, such as water. Due to the diversity of species and the range in physicochemical conditions in natural ecosystems, concentration ratios can vary by orders of magnitude, even within similar species. Therefore, to improve model input parameter values for application in aquatic systems, freshwater concentration ratios were collated or calculated from national grey literature, Russian language publications, and refereed papers. Collated data were then input into an international database that is being established by the International Atomic Energy Agency. The freshwater database enables entry of information for all radionuclides listed in ICRP (1983), in addition to the corresponding stable elements, and comprises a total of more than 16,500 concentration ratio (CRwo-water) values. Although data were available for all broad wildlife groups (with the exception of birds), data were sparse for many organism types. For example, zooplankton, crustaceans, insects and insect larvae, amphibians, and mammals, for which there were CRwo-water values for less than eight elements. Coverage was most comprehensive for fish, vascular plants, and molluscs. To our knowledge, the freshwater database that has now been established represents the most comprehensive set of CRwo-water values for freshwater species currently available for use in radiological environmental assessments

  14. Establishing a database of radionuclide transfer parameters for freshwater wildlife.

    Science.gov (United States)

    Yankovich, T; Beresford, N A; Fesenko, S; Fesenko, J; Phaneuf, M; Dagher, E; Outola, I; Andersson, P; Thiessen, K; Ryan, J; Wood, M D; Bollhöfer, A; Barnett, C L; Copplestone, D

    2013-12-01

    Environmental assessments to evaluate potentials risks to humans and wildlife often involve modelling to predict contaminant exposure through key pathways. Such models require input of parameter values, including concentration ratios, to estimate contaminant concentrations in biota based on measurements or estimates of concentrations in environmental media, such as water. Due to the diversity of species and the range in physicochemical conditions in natural ecosystems, concentration ratios can vary by orders of magnitude, even within similar species. Therefore, to improve model input parameter values for application in aquatic systems, freshwater concentration ratios were collated or calculated from national grey literature, Russian language publications, and refereed papers. Collated data were then input into an international database that is being established by the International Atomic Energy Agency. The freshwater database enables entry of information for all radionuclides listed in ICRP (1983), in addition to the corresponding stable elements, and comprises a total of more than 16,500 concentration ratio (CRwo-water) values. Although data were available for all broad wildlife groups (with the exception of birds), data were sparse for many organism types. For example, zooplankton, crustaceans, insects and insect larvae, amphibians, and mammals, for which there were CRwo-water values for less than eight elements. Coverage was most comprehensive for fish, vascular plants, and molluscs. To our knowledge, the freshwater database that has now been established represents the most comprehensive set of CRwo-water values for freshwater species currently available for use in radiological environmental assessments. PMID:23103210

  15. Population genetic structure of the freshwater snail, Bulinus globosus, (Gastropoda: Planorbidae) from selected habitats of KwaZulu-Natal, South Africa.

    Science.gov (United States)

    Mkize, Lwamkelekile Sitshilelo; Mukaratirwa, Samson; Zishiri, Oliver Tendayi

    2016-09-01

    The freshwater snail Bulinus globosus is an important intermediate host of Schistosoma haematobium, the causative agent of urinary schistosomiasis. This disease is of major health concern, especially in Africa where the majority of cases have been reported. In this study the inter- and intra-genetic diversity and population genetic structure of B. globosus from nine locations in the KwaZulu-Natal province of South Africa was studied using four polymorphic microsatellite loci (BgZ1-BgZ4). Moderate genetic diversity was detected within populations with a mean diversity (HE) of 0.49±0.09. The majority of populations significantly deviated from Hardy-Weinberg equilibrium (p<0.05), due to a deficit of heterozygotes. Such deviations may be due to founder events that were caused by bottlenecks that occurred as a result of frequent droughts and flooding that these snails' habitats are exposed to. Overall, the populations studied seem to be partially inbreeders/selfers with mean estimates of 0.24/0.38. A discernable genetic structure was elucidated among populations as evident by the mean pairwise FST of 0.58±0.13. There was no significant association between genetic and geographical distance among populations, an indication of limited gene flow. This increases the chances of populations losing alleles due to genetic drift. Populations in close proximity demonstrated high genetic differentiation (58.77% total variation) due to allelic differences between them. The sample populations fell into 12 clusters, however, the populations from uMkhanyakude and uThungulu exhibited no discernable genetic structure. Genetically, the Bhobhoyi site found within the uGu district was equidistant to the two main sampling regions. PMID:27267152

  16. Functionally and phylogenetically diverse plant communities key to soil biota.

    Science.gov (United States)

    Milcu, Alexandru; Allan, Eric; Roscher, Christiane; Jenkins, Tania; Meyer, Sebastian T; Flynn, Dan; Bessler, Holger; Buscot, François; Engels, Christof; Gubsch, Marlén; König, Stephan; Lipowsky, Annett; Loranger, Jessy; Renker, Carsten; Scherber, Christoph; Schmid, Bernhard; Thébault, Elisa; Wubet, Tesfaye; Weisser, Wolfgang W; Scheu, Stefan; Eisenhauer, Nico

    2013-08-01

    Recent studies assessing the role of biological diversity for ecosystem functioning indicate that the diversity of functional traits and the evolutionary history of species in a community, not the number of taxonomic units, ultimately drives the biodiversity--ecosystem-function relationship. Here, we simultaneously assessed the importance of plant functional trait and phylogenetic diversity as predictors of major trophic groups of soil biota (abundance and diversity), six years from the onset of a grassland biodiversity experiment. Plant functional and phylogenetic diversity were generally better predictors of soil biota than the traditionally used species or functional group richness. Functional diversity was a reliable predictor for most biota, with the exception of soil microorganisms, which were better predicted by phylogenetic diversity. These results provide empirical support for the idea that the diversity of plant functional traits and the diversity of evolutionary lineages in a community are important for maintaining higher abundances and diversity of soil communities.

  17. The problem of permissible doses of irradiation for biota

    International Nuclear Information System (INIS)

    The dose of acute irradiation or of chronic irradiation under which the biota's functioning is not disturbed is suggested as a permissible dose of irradiation for biota. On the basis of many separate experiments and observations, doses of chronic irradiation 1-3 gy/year are supposed to be permissible for higher plants and animals. The irradiation tolerance of microorganisms is considerably higher. The permissible doses of irradiation for the biota and for human beings are compared. The accepted maximum tolerance dose of irradiation of 10-3 gy/year for humans is determined to be groundless. We propose substituting the term open-quotes permissible dose.close quotes 28 refs., 3 figs

  18. Water hardness reduces the accumulation and toxicity of uranium in a freshwater macrophyte (Ceratophyllum demersum)

    Energy Technology Data Exchange (ETDEWEB)

    Markich, Scott J., E-mail: smarkich@optusnet.com.au

    2013-01-15

    ), and consequently, less U bound to physiologically active cell surface sites. In the absence of a biotic ligand model for U, the results of this study (together with previous work) reinforce the need for a more flexible, hardness-dependent, U guideline for the protection of selected freshwater biota. - Highlights: ► Effect of water hardness on U toxicity and accumulation in a freshwater macrophyte was studied. ► A 20-fold increase in water hardness resulted in a 4-fold decrease in U toxicity and accumulation. ► Ca provided a 4-fold greater protective effect against U toxicity and accumulation than Mg. ► Negligible differences in the percentages of key U species with increased water hardness ► Mechanisms of competition and/or electrostatic effects at the cell surface are proposed.

  19. LADTAP-2, Organ Doses to Man and Other Biota from Aquatic Environment

    International Nuclear Information System (INIS)

    1 - Description of problem or function: LADTAP2 performs environmental dose analyses for releases of liquid effluents from light-water nuclear power plants into surface waters during routine operation. The analyses estimate radiation doses to individuals, population groups, and biota from ingestion (aquatic foods, water, and terrestrial irrigated foods) and external exposure (shoreline, swimming, and boating) pathways. The calculated doses provide information for National Environmental Policy Act (NEPA) evaluations and for determining compliance with Appendix I of 10 CFR 50 (the 'ALARA' philosophy). The program consists of a hydrologic model chosen to represent mixing in the effluent impoundment system and the receiving surface waters and the exposure pathway models which estimate exposure of selected groups at various water usage locations in the environment. Two types of population doses are calculated. An ALARA analysis is performed based on exposure of people within 50 miles of the site, and a NEPA analysis is performed based on exposure of the entire U.S. population to effluents from the site. A population-dose analysis prepared in the form of a cost-benefit table presents the total-body and thyroid doses from each radionuclide released and the population doses (total-body and thyroid) per curie of each radionuclide released. 2 - Method of solution: The impoundment system is represented by one of four hydrologic models: direct release to the receiving water, linear flow with no mixing (the plug-flow model), linear flow through the impoundment with partial recirculation through the reactor (the partially mixed model), or complete mixing in the impoundment with partial recirculation through the reactor (the completely mixed model). The last three account for radiological decay during transit through the impoundment system. Optional models are available to estimate dilution in nontidal rivers and near-shore lake environments. The consequence calculation part of

  20. Field screening of water quality, bottom sediment, and biota associated with irrigation drainage in the Yuma Valley, Arizona, 1995

    Science.gov (United States)

    Tadayon, Saeid; King, K.A.; Andrews, Brenda; Roberts, William

    1997-01-01

    Because of concerns expressed by the U.S. Congress and the environmental community, the Department of the Interior began a program in late 1985 to identify the nature and extent of water-quality problems induced by irrigation that might exist in the western States. Surface water, bottom sediment, and biota were collected from March through September 1995 along the lower Colorado River and in agricultural drains at nine sites in the Yuma Valley, Arizona, and analyzed for selected inorganic and organic constituents. Analyses of water, bottom sediment, and biota were completed to determine if irrigation return flow has caused, or has the potential to cause, harmful effects on human health, fish, and wildlife in the study area. Concentrations of dissolved solids in surface-water samples collected in March generally did not vary substantially from surface-water samples collected in June. Concentrations of dissolved solids ranged from 712 to 3,000 milligrams per liter and exceeded the U.S. Environmental Protection Agency secondary maximum contaminant level of 500 milligrams per liter for drinking water. Concentrations of chloride in 9 of 18 water samples and concentrations of sulfate in 16 of 18 water samples exceeded the U.S. Environmental Protection Agency secondary maximum contaminant level of 250 milligrams per liter for drinking water. Calcium and sodium were the dominant cations, and chloride and sulfate were the dominant anions. The maximum selenium concentration of 8 micrograms per liter exceeded the U.S. Environmental Protection Agency aquatic-life chronic criterion of 5 micrograms per liter. Concentrations of lead in 7 of 18 water samples and concentrations of mercury in 4 of 18 water samples exceeded the aquatic-life cronic criteria of 3.2 and 0.012 micrograms per liter, respectively. Concentrations of antimony, beryllium, cadmium, and silver in the water samples were below analytical reporting limits. Arsenic was detected in 3 of 9 bottom-sediment samples

  1. Vertebrate radiations of the Jehol Biota and their environmental background

    Institute of Scientific and Technical Information of China (English)

    ZHOU Zhonghe

    2004-01-01

    @@ Significant progress has been made in recent years in the studies of various groups of the Jehol Biota, particularly concerning the origin of birds and their flight as well as the evolution of Early Cretaceous birds, dinosaurs, mammals, insects and flowering plants[1-5]. As a result, the Jehol Biota has become well known to both the scientific community and the public. The studies on the Jehol Biota also revealed the patterns and processes of the evolutionary radiations of many major groups of Early Cretaceous animals and plants, such as the earliest known radiation of angiosperms and birds, early differentiation of mammals and many Cretaceous dinosaurian groups. Notably, the radiations of the Jehol vertebrates share some similar patterns attributable to the particular environmental background. For instance, the Jehol vertebrate radiations are highlighted by the presence of abundant arboreal adaptations and herbivorous forms, thus closely linked to the forest environments. In addition, the differentiation of habitats and diets is also characteristic of the evolutionary radiations of pterosaurs, dinosaurs, birds and mammals in the Jehol Biota.

  2. Combined ecological risks of nitrogen and phosphorus in European freshwaters

    International Nuclear Information System (INIS)

    Eutrophication is a key water quality issue triggered by increasing nitrogen (N) and phosphorus (P) levels and potentially posing risks to freshwater biota. We predicted the probability that an invertebrate species within a community assemblage becomes absent due to nutrient stress as the ecological risk (ER) for European lakes and streams subjected to N and P pollution from 1985 to 2011. The ER was calculated as a function of species-specific tolerances to NO3− and total P concentrations and water quality monitoring data. Lake and stream ER averaged 50% in the last monitored year (i.e. 2011) and we observed a decrease by 22% and 38% in lake and stream ER (respectively) of river basins since 1985. Additionally, the ER from N stress surpassed that of P in both freshwater systems. The ER can be applied to identify river basins most subjected to eutrophication risks and the main drivers of impacts. - Highlights: • Ecological risk was estimated as response additions of N and P. • The risk posed by N stress is higher than that by P in European freshwaters. • Ecological risks have remained unchanged in most European river basins. - Quantifying the ecological risk of invertebrate losses due to N and P pollution

  3. Davis Pond Freshwater Prediversion Biomonitoring Study: Freshwater Fisheries and Eagles

    Science.gov (United States)

    Jenkins, Jill A.; Bourgeois, E. Beth; Jeske, Clint W.

    2008-01-01

    In January 2001, the construction of the Davis Pond freshwater diversion structure was completed by the U.S. Army Corps of Engineers. The diversion of freshwater from the Mississippi River is intended to mitigate saltwater intrusion from the Gulf of Mexico and to lessen the concomitant loss of wetland areas. In addition to the freshwater inflow, Barataria Bay basin would receive nutrients, increased flows of sediments, and water-borne and sediment-bound compounds. The purpose of this biomonitoring study was, therefore, to serve as a baseline for prediversion concentrations of selected contaminants in bald eagle (Haliaeetus leucocephalus) nestlings (hereafter referred to as eaglets), representative freshwater fish, and bivalves. Samples were collected from January through June 2001. Two similarly designed postdiversion studies, as described in the biological monitoring program, are planned. Active bald eagle nests targeted for sampling eaglet blood (n = 6) were generally located southwest and south of the diversion structure. The designated sites for aquatic animal sampling were at Lake Salvador, at Lake Cataouatche, at Bayou Couba, and along the Mississippi River. Aquatic animals representative of eagle prey were collected. Fish were from three different trophic levels and have varying feeding strategies and life histories. These included herbivorous striped mullet (Mugil cephalus), omnivorous blue catfish (Ictalurus furcatus), and carnivorous largemouth bass (Micropterus salmoides). Three individuals per species were collected at each of the four sampling sites. Freshwater Atlantic rangia clams (Rangia cuneata) were collected at the downstream marsh sites, and zebra mussels (Dreissena spp.) were collected on the Mississippi River. The U.S. Geological Survey (USGS) Biomonitoring of Environmental Status and Trends (BEST) protocols served as guides for fish sampling and health assessments. Fish are useful for monitoring aquatic ecosystems because they accumulate

  4. A New Fluorinated Surfactant Contaminant in Biota: Perfluorobutane Sulfonamide in Several Fish Species.

    Science.gov (United States)

    Chu, Shaogang; Letcher, Robert J; McGoldrick, Daryl J; Backus, Sean M

    2016-01-19

    Environmental contamination and regulation of longer-chain perfluoroalkyl substances (PFASs) such as perfluorooctanesulfonate (PFOS) has given rise to the increased use of shorter-chain PFASs as alternatives in new products, although confirmation of their presence in the environment remains limited. In this study, the PFAS alternative, perfluoro-1-butane-sulfonamide (FBSA), was identified for the first time in biota in homogenate samples of fish by liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-Q-ToF-MS) and quantified by ultra high performance liquid chromatography-triple quadrupole mass spectrometry (UHPLC-QQQ-MS/MS). In one flounder (Platichthys flesus) muscle sample from the Western Scheldt, The Netherlands, FBSA concentration was at 80.12 ng/g wet weight (w.w.) and was exceeded only by PFOS. FBSA was also detected in 32 out of 33 samples of freshwater fish collected (2009-2010) from water bodies across Canada. In lake trout (Salvelinus namaycush) from northern Canada (e.g., Lake Kusawa (Yukon Territory), Great Bear Lake (Northwest Territories and in the Arctic), and Lake Athabasca (northern Alberta)), the concentrations of FBSA ranged from below method detection limit (supermarket in Ottawa (ON, Canada), FBSA concentrations were the lowest of all fish and ranged from chain perfluoroalkyl-based products.

  5. Soil Biota and Litter Decay in High Arctic Ecosystems

    Science.gov (United States)

    González, G.; Rivera, F.; Makarova, O.; Gould, W. A.

    2006-12-01

    Frost heave action contributes to the formation of non-sorted circles in the High Arctic. Non-sorted circles tend to heave more than the surrounding tundra due to deeper thaw and the formation of ice lenses. Thus, the geomorphology, soils and vegetation on the centers of the patterned-ground feature (non-sorted circles) as compared to the surrounding soils (inter-circles) can be different. We established a decomposition experiment to look at in situ decay rates of the most dominant graminoid species on non-sorted circles and adjacent inter-circle soils along a climatic gradient in the Canadian High Arctic as a component of a larger study looking at the biocomplexity of small-featured patterned ground ecosystems. Additionally, we investigated variation in soil chemical properties and biota, including soil microarthropods and microbial composition and biomass, as they relate to climate, topographic position, and litter decay rates. Our three sites locations, from coldest to warmest, are Isachsen, Ellef Ringnes Island (ER), NU (bioclimatic subzone A); Mould Bay (MB), Prince Patrick Island, NT (bioclimatic subzone B), and Green Cabin (GC), Aulavik National Park, Thomsen River, Banks Island, NT (bioclimatic subzone C). Our sample design included the selection of 15 non-sorted circles and adjacent inter-circle areas within the zonal vegetation at each site (a total of 90 sites), and a second set of 3 non-sorted circles and adjacent inter-circle areas in dry, mesic and wet tundra at each of the sites. Soil invertebrates were sampled at each site using both pitfall traps, soil microbial biomass was determined using substrate induced respiration and bacterial populations were determined using the most probable number method. Decomposition rates were measured using litterbags and as the percent of mass remaining of Carex misandra, Luzula nivalis and Alopecuris alpinus in GC, MB and ER, respectively. Our findings indicate these graminoid species decayed significantly over

  6. Determination of methylmercury in marine biota samples: method validation.

    Science.gov (United States)

    Carrasco, Luis; Vassileva, Emilia

    2014-05-01

    Regulatory authorities are expected to measure concentration of contaminants in foodstuffs, but the simple determination of total amount cannot be sufficient for fully judging its impact on the human health. In particular, the methylation of metals generally increases their toxicity; therefore validated analytical methods producing reliable results for the assessment of methylated species are highly needed. Nowadays, there is no legal limit for methylmercury (MeHg) in food matrices. Hence, no standardized method for the determination of MeHg exists within the international jurisdiction. Contemplating the possibility of a future legislative limit, a method for low level determination of MeHg in marine biota matrixes, based on aqueous-phase ethylation followed by purge and trap and gas chromatography (GC) coupled to pyrolysis-atomic fluorescence spectrometry (Py-AFS) detection, has been developed and validated. Five different extraction procedures, namely acid and alkaline leaching assisted by microwave and conventional oven heating, as well as enzymatic digestion, were evaluated in terms of their efficiency to extract MeHg from Scallop soft tissue IAEA-452 Certified Reference Material. Alkaline extraction with 25% (w/w) KOH in methanol, microwave-assisted extraction (MAE) with 5M HCl and enzymatic digestion with protease XIV yielded the highest extraction recoveries. Standard addition or the introduction of a dilution step were successfully applied to overcome the matrix effects observed when microwave-assisted extraction using 25% (w/w) KOH in methanol or 25% (w/v) aqueous TMAH were used. ISO 17025 and Eurachem guidelines were followed to perform the validation of the methodology. Accordingly, blanks, selectivity, calibration curve, linearity (0.9995), working range (1-800pg), recovery (97%), precision, traceability, limit of detection (0.45pg), limit of quantification (0.85pg) and expanded uncertainty (15.86%, k=2) were assessed with Fish protein Dorm-3 Certified

  7. A freshwater biodiversity hotspot under pressure – assessing threats and identifying conservation needs for ancient Lake Ohrid

    OpenAIRE

    G. Kostoski; Albrecht, C.; S. Trajanovski; Wilke, T.

    2010-01-01

    Immediate conservation measures for world-wide freshwater resources are of eminent importance. This is particularly true for so-called ancient lakes. While these lakes are famous for being evolutionary theatres, often displaying an extraordinarily high degree of biodiversity and endemism, in many cases these biota are also experiencing extreme anthropogenic impact.

    Lake Ohrid, a major European biodiversity hotspot situated in a trans-frontier setting on the Balkans, is a ...

  8. Fatty Acid Composition and Levels of Selected Polyunsaturated Fatty Acids in Four Commercial Important Freshwater Fish Species from Lake Victoria, Tanzania

    Directory of Open Access Journals (Sweden)

    Agnes Robert

    2014-01-01

    Full Text Available Fatty acids (FAs particularly ω3 and ω6 polyunsaturated fatty acids (PUFAs play important role in human health. This study aimed to investigate the composition and levels of selected ω3 PUFAs in four commercial fish species, Nile perch (Lates niloticus, Nile tilapia (Oreochromis niloticus, Tilapia zillii, and dagaa (Rastrineobola argentea from Mwanza Gulf in Lake Victoria. The results indicated that 36 types of FAs with different saturation levels were detected. These FAs were dominated by docosahexaenoic (DHA, eicosapentaenoic (EPA, docosapentaenoic (DPA, and eicosatetraenoic acids. O. niloticus had the highest composition of FAs (34 compared to L. niloticus (27, T. zillii (26, and R. argentea (21. The levels of EPA differed significantly among the four commercial fish species (F=6.19,  P=0.001. The highest EPA levels were found in R. argentea followed by L. niloticus and O. niloticus and the lowest in T. zillii. The DPA levels showed no significant difference among the four fish species studied (F=0.652,  P=0.583. The study concluded that all four commercial species collected from Mwanza Gulf are good for human health, but R. argentea is the best for consumption because it contains higher levels of ω3 FAs, mainly EPA.

  9. THE EDIACARA BIOTA: Neoproterozoic Origin of Animals and Their Ecosystems

    Science.gov (United States)

    Narbonne, Guy M.

    2005-01-01

    The Ediacara biota (575-542 Ma) marks the first appearance of large, architecturally complex organisms in Earth history. Present evidence suggests that the Ediacara biota included a mixture of stem- and crown-group radial animals, stem-group bilaterian animals, "failed experiments" in animal evolution, and perhaps representatives of other eukaryotic kingdoms. These soft-bodied organisms were preserved under (or rarely within) event beds of sand or volcanic ash, and four distinct preservational styles (Flinders-, Fermeuse-, Conception-, and Nama-style) profoundly affected the types of organisms and features that could be preserved. Even the earliest Ediacaran communities (575-565 Ma) show vertical and lateral niche subdivision of the sessile, benthic, filter-feeding organisms, which is strikingly like that of Phanerozoic and modern communities. Later biological and ecological innovations include mobility (>555 Ma), calcification (550 Ma), and predation (extinction andor biological interactions with the rapidly evolving animals of the Cambrian explosio

  10. Functionally and phylogenetically diverse plant communities key to soil biota

    OpenAIRE

    Milcu, Alexandru; Allan, Eric; Roscher, Christiane; Jenkins, Tania; Meyer, Sebastian T.; Flynn, Dan; Bessler, Holger; Buscot, François; Engels, Christof; Gubsch, Marlén; König, Stephan; Lipowsky, Annett; Loranger, Jessy; Renker, Carsten; Scherber, Christoph

    2013-01-01

    Recent studies assessing the role of biological diversity for ecosystem functioning indicate that the diversity of functional traits and the evolutionary history of species in a community, not the number of taxonomic units, ultimately drives the biodiversity–ecosystem-function relationship. Here, we simultaneously assessed the importance of plant functional trait and phylogenetic diversity as predictors of major trophic groups of soil biota (abundance and diversity), six years from the onset ...

  11. Filling knowledge gaps in radiation protection methodologies for non-human biota. Final summary report

    Energy Technology Data Exchange (ETDEWEB)

    Brown, J.; Gjelsvik, R. (Norwegian Radiation Protection Authority (Norway)); Holm, E. (Univ. of Lund (Sweden)); Roos, P. (Technical Univ. of Denmark, Risoe National Lab. for Sustainable Energy, Roskilde (Denmark)); Saxen, R.; Outola, I. (Radiation and Nuclear Safety Authority (Finland))

    2009-03-15

    The activities of the GAPRAD project are summarised in this report. The background and rationale to GAPRAD are presented and explained. Most notably this relates to a lack of information on naturally occuring radionuclides in terrestrial and aquatic systems that have direct applicability for use in environmental impact assessments. Results from field activities are presented from the Dovrefjell area in Norway (terrestrial study) and selected lake and brackish water systems in Finland. The data mainly concern activity concentrations of Po-210 in environmental media and selected biota allowing concentration ratios to be derived where appropriate. Furthermore, details in relation to Po-210 uptake and biokinetics in humans based on experimental work conducted within the project are presented. (au)

  12. Filling knowledge gaps in radiation protection methodologies for non-human biota. Final summary report

    International Nuclear Information System (INIS)

    The activities of the GAPRAD project are summarised in this report. The background and rationale to GAPRAD are presented and explained. Most notably this relates to a lack of information on naturally occuring radionuclides in terrestrial and aquatic systems that have direct applicability for use in environmental impact assessments. Results from field activities are presented from the Dovrefjell area in Norway (terrestrial study) and selected lake and brackish water systems in Finland. The data mainly concern activity concentrations of Po-210 in environmental media and selected biota allowing concentration ratios to be derived where appropriate. Furthermore, details in relation to Po-210 uptake and biokinetics in humans based on experimental work conducted within the project are presented. (au)

  13. Arctic freshwater synthesis: Introduction

    Science.gov (United States)

    Prowse, T.; Bring, A.; Mârd, J.; Carmack, E.

    2015-11-01

    In response to a joint request from the World Climate Research Program's Climate and Cryosphere Project, the International Arctic Science Committee, and the Arctic Council's Arctic Monitoring and Assessment Program, an updated scientific assessment has been conducted of the Arctic Freshwater System (AFS), entitled the Arctic Freshwater Synthesis (AFSΣ). The major reason for joint request was an increasing concern that changes to the AFS have produced, and could produce even greater, changes to biogeophysical and socioeconomic systems of special importance to northern residents and also produce extra-Arctic climatic effects that will have global consequences. Hence, the key objective of the AFSΣ was to produce an updated, comprehensive, and integrated review of the structure and function of the entire AFS. The AFSΣ was organized around six key thematic areas: atmosphere, oceans, terrestrial hydrology, terrestrial ecology, resources and modeling, and the review of each coauthored by an international group of scientists and published as separate manuscripts in this special issue of Journal of Geophysical Research-Biogeosciences. This AFSΣ—Introduction reviews the motivations for, and foci of, previous studies of the AFS, discusses criteria used to define the domain of the AFS, and details key characteristics of the definition adopted for the AFSΣ.

  14. Progress and significance in research on the early Middle Cambrian Kaili Biota, Guizhou Province,China

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Important progress in research on the Kaili Biota has been made recently. Many interesting components from Chengjiang Biota and Burgess Shale Biota have been discovered, e.g. Microdictyon of lobopodia; Ottoia, Palaeoscolex of worms; Naraoia, Marrella of Trilobitioidea, Mollisonia, anamalocarids and other non-trilobite arthropods; and new sorts of echinoder-mas, macroalage fossils and so on. Recent work on the Kaili Biota has resulted in the following developments: (i) an increase in the number of animal genera, up to more than 100 genera in total, so that the Kaili Biota has become the third most diverse of the Burgess Shale-type Biota after the Burgess Shale and Chengjiang Biotas; and (ii) the most noteworthy fossils in the Kaili Biota are echinoderms, non-trilobite arthropods and soft-bodied medusiform fossils, especially the most diverse echinoderms. The progress provides envidence for the biodiversity of marine organisms presented after the "Cambrian Explosion" and serves as a link between the earlist Cambrian Chengjiang Biota and late early Middle Cambrian Burgess Shale Biota. It is of great significance in the reconstruction of the Cambrian palaeoplate, palaeongeography and in research on taphonomy.

  15. Evolution of insect diversity in the Jehol Biota

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Insects of the Jehol Biota,also known as the Jehol Entomofauna,can be divided into three phases,approximately corresponding to the early,middle,and late Jehol Biota.The early phase of the entomofauna is found in the Dabeigou Formation and its coeval horizons(ca.135-130 Ma).The middle phase is recorded from the lower-middle Yixian Formation(underlying the Jingangshan Bed) and its coeval strata(ca.130-122.5 Ma).The late phase is found in the lower Jiufotang Formation,the upper Yixian Formation(the Jingangshan and Huanghuashan beds) and their coeval horizons(ca.122.5-120 Ma).In major distribution areas of the Jehol Biota,the entomofauna changed greatly in species diversity with about 150 species in about 40 families and 11 orders in the early phase,a great increase up to about 500 species in about 100 families and 16 orders in the middle phase,and a decline to about 300 species in about 80 families and 14 orders in the late phase.The entomofauna can also be divided into four insect communities based on habitats or five insect groups based on feeding habits.Each community or group varied in species diversity in a similar trend to the whole entomofauna.However,it kept a comparatively stable position in the ecosystem.Of the four communities,the highest species diversity occurred in the forest community,followed by the aquatic,the soil,and the alpine communities.Of the five groups,the highest species diversity appeared in the phytophagous group,followed by the carnivorous,the parasitic,the saprophagous,and the heterophagous groups.

  16. Community structure and composition of the Cambrian Chengjiang biota

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Based on previously published species data(228 species in over 18 phyla) and field sampling(114 species and 18406 individuals) in the Chengjiang-Haikou-Anning area,we analyzed quantitatively the paleocommunity composition and structure of the Cambrian Chengjiang biota(Cambrian Series 2,eastern Yunnan,China).Arthropods dominate the community both in species diversity(species:37%) and in abundance(individuals:51.8%).Priapulids(individuals:22.6%) and brachiopods(individuals:16.3%) follow in abundance rank.The arthropod Kunmingella douvillei(26.2%),the priapulid Cricocosmia jinning-ensis(15.4%),and the brachiopod Diandongia pista(11%) are the three most abundant species.Ecological analyses show that the community was dominated by epifaunal organisms(species:63%,individuals:68.4%) followed by infaunal organisms(species:11.9%,individuals:25.9%),nektobenthic organisms(species:11.5%,individuals:2.6%),and pelagic organisms(species:5.3%,individuals:3.1%).The diverse feeding strategies,dominated by suspension feeders(species:35.6%,individuals:26.1%) and hunter/scavengers(species:31.1%,individuals:40.4%),indicate the former existence of a complex food chain and intense competition.Epifaunal vagrant omnivores(28.2%),infaunal vagrant hunter/scavengers(19.8%),epifaunal sessile suspension feeders(17.7%),and epifaunal vagrant hunter/scavengers(15.3%) were the most abundant ecological groups,represented primarily by arthropods,poriferans,priapulids,and brachiopods.Ecological group analyses reveal that the early Cambrian Chengjiang biota is similar in community patterns and functional relations to modern biotas in shallow marine settings.

  17. Comparative radiation impact on biota and man in the area affected by the accident at the Chernobyl nuclear power plant

    Energy Technology Data Exchange (ETDEWEB)

    Fesenko, S.V. [Russian Institute of Agricultural Radiology and Agroecology, Kievskoe shosse, Kaluga region, Obninsk 249020 (Russian Federation) and International Atomic Energy Agency, Agency' s Laboratories, Seibersdorf A-2444 (Austria)]. E-mail: s.fesenko@iaea.org; Alexakhin, R.M. [Russian Institute of Agricultural Radiology and Agroecology, Kievskoe shosse, Kaluga region, Obninsk 249020 (Russian Federation); Geras' kin, S.A. [Russian Institute of Agricultural Radiology and Agroecology, Kievskoe shosse, Kaluga region, Obninsk 249020 (Russian Federation); Sanzharova, N.I. [Russian Institute of Agricultural Radiology and Agroecology, Kievskoe shosse, Kaluga region, Obninsk 249020 (Russian Federation); Spirin, Ye.V. [Russian Institute of Agricultural Radiology and Agroecology, Kievskoe shosse, Kaluga region, Obninsk 249020 (Russian Federation); Spiridonov, S.I. [Russian Institute of Agricultural Radiology and Agroecology, Kievskoe shosse, Kaluga region, Obninsk 249020 (Russian Federation); Gontarenko, I.A. [Russian Institute of Agricultural Radiology and Agroecology, Kievskoe shosse, Kaluga region, Obninsk 249020 (Russian Federation); Strand, P. [Norwegian Radiation Protection Authority, Oesteras (Norway)

    2005-07-01

    A methodological approach for a comparative assessment of ionising radiation effects on man and non-human species, based on the use of Radiation Impact Factor (RIF) - ratios of actual exposure doses to biota species and man to critical dose is described. As such doses, radiation safety standards limiting radiation exposure of man and doses at which radiobiological effects in non-human species were not observed after the Chernobyl accident, were employed. For the study area within the 30 km ChNPP zone dose burdens to 10 reference biota groups and the population (with and without evacuation) and the corresponding RIFs were calculated. It has been found that in 1986 (early period after the accident) the emergency radiation standards for man do not guarantee adequate protection of the environment, some species of which could be affected more than man. In 1991 RIFs for man were considerably (by factor of 20.0-1.1 x 10{sup 5}) higher compared with those for selected non-human species. Thus, for the long term after the accident radiation safety standards for man are shown to ensure radiation safety for biota as well.

  18. Burgess shale-type biotas were not entirely burrowed away

    DEFF Research Database (Denmark)

    Gaines, Robert R.; Droser, Mary L.; Orr, Patrick J.;

    2012-01-01

    Burgess Shale-type biotas occur globally in the Cambrian record and offer unparalleled insight into the Cambrian explosion, the initial Phanerozoic radiation of the Metazoa. Deposits bearing exceptionally preserved soft-bodied fossils are unusually common in Cambrian strata; more than 40 are now......, however, suggest a more complex scenario. Ichnologic and microstratigraphic data from Burgess Shale-type deposits indicate that (1) bioturbation exerts a limiting effect on soft-bodied preservation; (2) the observed increase in the depth and extent or bioturbation following the Middle Cambrian would have...

  19. Relationship between water solubility of chlorobenzenes and their effects on a freshwater green alga

    Energy Technology Data Exchange (ETDEWEB)

    Wong, P.T.S.; Chau, Y.K.; Rhamey, J.S.; Docker, M.

    1984-01-01

    The effective concentrations of benzene and 12 chlorobenzenes that reduced 50% of the primary productivity (EC/sub 50/) of a freshwater green alga, Ankistrodesmus falcatus, were determined. Benzene was the least toxic chemical and the toxicity increased as the degree of chlorine substitution in the aromatic ring increased. No EC/sub 50/ value could be obtained for HCB. A quantitative relationship was found to exist between water solubility, lipophilicity and the EC/sub 50/. A good correlation was also observed between the EC/sub 50/ for this alga and other toxicity data for various aquatic biota.

  20. Reviewing the serotonin reuptake inhibitors (SSRIs) footprint in the aquatic biota: uptake, bioaccumulation and ecotoxicology.

    Science.gov (United States)

    Silva, Liliana J G; Pereira, André M P T; Meisel, Leonor M; Lino, Celeste M; Pena, Angelina

    2015-02-01

    Selective serotonin re-uptake inhibitors (SSRIs) antidepressants are amongst the most prescribed pharmaceutical active substances throughout the world. Their presence, already described in different environmental compartments such as wastewaters, surface, ground and drinking waters, and sediments, and their remarkable effects on non-target organisms justify the growing concern about these emerging environmental pollutants. A comprehensive review of the literature data with focus on their footprint in the aquatic biota, namely their uptake, bioaccumulation and both acute and chronic ecotoxicology is presented. Long-term multigenerational exposure studies, at environmental relevant concentrations and in mixtures of related compounds, such as oestrogenic endocrine disruptors, continue to be sparse and are imperative to better know their environmental impact.

  1. Biodiversity and taphonomy of the Early Cambrian Guanshan biota,eastern Yunnan

    Institute of Scientific and Technical Information of China (English)

    Michael; STEINER

    2010-01-01

    The Guanshan biota from eastern Yunnan(Cambrian Series 2,early Stage 4) is a Burgess Shale-type fossil biota with abundant exceptionally preserved soft-bodied fossils after the discovery of the well-known Cambrian Chengjiang fauna and Kaili biota in South China.The geological settings,sedimentology,taphonomy,and the fossil assemblage of the Guanshan biota are briefly summarized here.The Guanshan biota consists of about 60 taxa belonging to more than 10 metazoan groups and algae,among which the lobopods,eldonids,hyolithids with helens,and green algae are reported for the first time.The common occurrence of soft-bodied preservation in many groups,notably the trilobites and brachiopods,makes the Guanshan biota a significant fossil lagersttte for understanding the metazoan evolution during Cambrian explosion and taphonomy of the Burgess Shale-type fossils.

  2. Population Dynamics of Biota on the Roots of Azolla microphylla Kaulfuss

    OpenAIRE

    NITA ETIKAWATI; JUTONO

    2000-01-01

    Azolla was a special fern that their associations with Anabaena azollae able to fix free nitrogen from air, to produce protein. Although by the ages, biota diversity those habits on the roots of Azolla increased and effected to protein concentration. The research was to find out population dynamics of biota on the roots of Azolla microphylla Kaulfuss and the growth peak. This study used Completely Randomized Design with 10 kinds of biota, i.e. bacteria, Fungi, Actinomycetes, Protozoa, Alga, C...

  3. Summary of information on aquatic biota and their habitats in the Willamette Basin, Oregon, through 1995

    Science.gov (United States)

    Altman, Bob; Henson, C.M.; Waite, I.R.

    1997-01-01

    Available information on aquatic biota of the Willamette Basin was reviewed and summarized to describe current and historical conditions as part of the U.S. Geological Survey's National Water-Quality Assessment Program. Biological parameters emphasized include the status, distribution, and trends of aquatic biota, particularly algae, macroinvertebrates, and fish; the condition of aquatic and riparian habitat in which these biota reside; and the response of these biota to natural and human-associated impacts, including the level, type, and effect of contaminants.

  4. Soil biota community structure and abundance under agricultural intensification and extensification.

    Science.gov (United States)

    Postma-Blaauw, Maria B; de Goede, Ron G M; Bloem, Jaap; Faber, Jack H; Brussaard, Lijbert

    2010-02-01

    Understanding the impacts of agricultural intensification and extensification on soil biota communities is useful in order to preserve and restore biological diversity in agricultural soils and enhance the role of soil biota in agroecosystem functioning. Over four consecutive years, we investigated the effects of agricultural intensification and extensification (including conversion of grassland to arable land and vice versa, increased and decreased levels of mineral fertilization, and monoculture compared to crop rotation) on major soil biota group abundances and functional diversity. We integrated and compared effects across taxonomic levels to identify sensitive species groups. Conversion of grassland to arable land negatively affected both abundances and functional diversity of soil biota. Further intensification of the cropping system by increased fertilization and reduced crop diversity exerted smaller and differential effects on different soil biota groups. Agricultural intensification affected abundances of taxonomic groups with larger body size (earthworms, enchytraeids, microarthropods, and nematodes) more negatively than smaller-sized taxonomic groups (protozoans, bacteria, and fungi). Also functional group diversity and composition were more negatively affected in larger-sized soil biota (earthworms, predatory mites) than in smaller-sized soil biota (nematodes). Furthermore, larger soil biota appeared to be primarily affected by short-term consequences of conversion (disturbance, loss of habitat), whereas smaller soil biota were predominantly affected by long-term consequences (probably loss of organic matter). Reestablishment of grassland resulted in increased abundances of soil biota groups, but since not all groups increased in the same measure, the community structure was not completely restored. We concluded that larger-sized soil biota are more sensitive to agricultural intensification than smaller-sized soil biota. Furthermore, since larger

  5. Toxicity of coal mining effluents on freshwater mussels and aquatic biota in the upper Tennessee River Basin

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Based on these results, the Service recommends that mining effluents be analyzed for the full suite of metals and water quality parameters (pH, hardness, specific...

  6. Phylogenetic diversity of freshwater picocyanobacteria

    OpenAIRE

    Callieri, Cristiana; Coci, Manuela

    2012-01-01

    Picocyanobacteria are photosynthetic prokaryotes, coccoid or rod-shaped, with a cell diameter < 2 ?m. They are common in lakes and oceans, and abundant across a wide spectrum of trophic conditions (Callieri et al 2012). The dominant genus of freshwater picocyanobacteria is Synechococcus. Analysis of 16S rRNA gene of freshwater Synechococcus showed its polyphyletic origin, requiring better insights in the present classification of the genus and possibly a revision. We isolated more than 40 pic...

  7. The freshwater crab, Trichodactylus fluviatilis (Latreille, 1828) (Crustacea, Decapoda, Trichodactylidae), as perceived by the inhabitants of the county of Pedra Branca, Bahia, Brazil

    OpenAIRE

    Eraldo Medeiros Costa Neto

    2007-01-01

    Freshwater crabs are key elements of the aquatic biota of streams, rivers, lakes, and dams because of their ecological and economic importance. Considering that Trichodactylus fluviatilis (Latreille, 1828) is an important source of food for the human settlements that inhabit the places of its occurrence, this article records, for the first time, an ethnocarcinological study carried out with the inhabitants of Pedra Branca county, Bahia State. Data were obtained from February to June 2005 by m...

  8. Assessing impacts of ionizing radiation on non-human biota: the ERICA tool

    International Nuclear Information System (INIS)

    There have been significant developments in the last few years concerning methods to explicitly quantify impacts on the environment arising from exposure by ionising radiation. Central to the ERICA integrated approach is the quantification of environmental risk whereby data on environmental transfer and dosimetry are combined to provide a measure of exposure which is compared to exposure levels at which detrimental effects are known to occur. In view of the large data sets underpinning the assessment approach and the potential to introduce errors when performing numerous calculations manually, a supporting computer-based tool (the ERICA Tool) has been developed. The ERICA Tool is a computerised, flexible software system that has a structure based upon the ERICA Integrated Assessment tiered approach to assessing the radiological risk to biota. The user is guided through the assessment process, recording information and decisions as the assessment progresses. The tool allows the necessary calculations to be performed to estimate risks to selected biota. Tier 1 assessments use pre-calculated environmental media concentration limits to estimate risk quotients and require inputs in the form of media concentrations. At Tier 2 dose-rates are calculated but at this stage, the user is allowed to examine and edit most of the parameters used in the calculation. For Tier 3 assessments, the same flexibility as Tier 2 is allowed but assessments may be run probability if the underling parameter probability distribution functions are defined. Results from the tool can be put into context using incorporated data on dose-effects relationships and background dose-rates. (author)

  9. Modelling Radiation Exposure and Radionuclide Transfer for Non-human Species. Report of the Biota Working Group of EMRAS Theme 3

    International Nuclear Information System (INIS)

    Internationally, the ICRP, IAEA and European Commission (EC) are addressing environmental protection as an element of their revision of Recommendations and Basic Safety Standards. Some countries already have requirements and guidelines for the protection of non-human biota. For instance, in England and Wales, the requirement to assess impacts affecting Natura 2000 sites has been interpreted to include ionising radiation. In the USA, biota protection guidelines and dose rates are contained in USDOE Orders 5400.5 and 450.1. In response to these developments, a number of models and approaches have been developed specifically to estimate the exposure of non-human biota to ionising radiations. Some countries (e.g. Canada, Finland, England and Wales, and the USA) are now using these within their national regulatory frameworks for (existing and proposed) nuclear and other sites that may release radioactivity to the environment. Software and/or documentation for some of these approaches are readily available and hence third parties are able to use them when conducting assessments. The Biota Working Group (BWG) of the IAEA Environmental Modelling for Radiation Safety programme was formed in 2004 to address the relative lack of validation and intercomparison of the different models and approaches. The primary objective of the BWG, was: 'to improve Member State's capabilities for protection of the environment by comparing and validating models being used, or developed, for biota dose assessment (that may be used) as part of regulatory process of licensing and compliance monitoring of authorised releases of radionuclides'. Group members included modellers, regulators, industry and researchers. In total, 15 models and approaches were applied to one or more of the four exercises conducted by the BWG. The models/approaches applied encompass those being developed, and in some instances, used in a regulatory context, in Belgium, Canada, France, Lithuania, Russia, the UK and the USA

  10. Taiwan's industrial heavy metal pollution threatens terrestrial biota

    International Nuclear Information System (INIS)

    The bioconcentration levels of essential (Cu, Fe, Mg, Mn, and Zn) and non-essential (As, Cd, Hg, Pb, and Sn) elements have been investigated in different terrestrial biota such as fungi, plant, earthworm, snail, crab, insect, amphibian, lizard, snake, and bat including the associated soil, to investigate the ecosystem health status in Kenting National Park, Taiwan. High bioconcentrations of Cd, Hg, and Sn in snail, earthworm, crab, lizard, snake, and bat indicated a contaminated terrestrial ecosystem. High concentrations of Cd, Hg, and Sn in plant species, effective bioaccumulation of Cd by earthworm, snail, crab and bat, as well as very high levels of Hg found in invertebrates, amphibians, and reptiles revealed a strong influence from industrial pollution on the biotic community. This study for the first time presents data on the impact of heavy metal pollution on various terrestrial organisms in Taiwan. - Metal effects occur at any terrestrial levels in Taiwan

  11. The Human Vaginal Bacterial Biota and Bacterial Vaginosis

    Directory of Open Access Journals (Sweden)

    Sujatha Srinivasan

    2008-01-01

    Full Text Available The bacterial biota of the human vagina can have a profound impact on the health of women and their neonates. Changes in the vaginal microbiota have been associated with several adverse health outcomes including premature birth, pelvic inflammatory disease, and acquisition of HIV infection. Cultivation-independent molecular methods have provided new insights regarding bacterial diversity in this important niche, particularly in women with the common condition bacterial vaginosis (BV. PCR methods have shown that women with BV have complex communities of vaginal bacteria that include many fastidious species, particularly from the phyla Bacteroidetes and Actinobacteria. Healthy women are mostly colonized with lactobacilli such as Lactobacillus crispatus, Lactobacillus jensenii, and Lactobacillus iners, though a variety of other bacteria may be present. The microbiology of BV is heterogeneous. The presence of Gardnerella vaginalis and Atopobium vaginae coating the vaginal epithelium in some subjects with BV suggests that biofilms may contribute to this condition.

  12. Agrochemical residue-biota interactions in soil and aquatic ecosystems

    International Nuclear Information System (INIS)

    Two FAO/IAEA coordinated research programmes are concerned with isotopic tracer-aided studies of agrochemical residue-biota interactions in soils and aquatic ecosystems. They currently involve 18 studies in 14 countries: Brazil, Canada, Egypt, F.R. Germany, Hungary, India, Indonesia, Iraq, Israel, Malaysia, Thailand, Turkey, USA and USSR. The aim was to develop, standardize and apply labelled substrate techniques for comparative assays of primary autotrophic and microheterotrophic production and decay, and complementary tracer techniques to determine the fate, persistence and bioconcentration of trace contaminants. Comparable data were studied concerning the current status of water bodies and likely changes due to contaminants. Soil capacity to decompose undesirable contaminants and residues, and to promote desirable transformations were studied. The techniques were also applied as a diagnostic and prognostic tool, with priority given to rice ecosystems

  13. A conodont-based Middle Triassic age assignment for the Luoping Biota of Yunnan, China

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The Luoping Biota consists of abundant and well-preserved marine fishes, reptiles, invertebrates, and plants. It occurs in the Middle Triassic Guanling Formation in Daaozi Village of Luoping County, Yun-nan Province, China. Based on conodonts, the Luoping Biota is determined to lie within the Nicoraella kockeli Zone, which is assigned to the Pelsonian substage of the Anisian.

  14. THE IMPORTANCE OF THE BIODIVERSITY OF SOIL BIOTA IN ARID ECOSYSTEMS

    Science.gov (United States)

    The importance of soil biota in maintaining ecosystem integrity is examined by a review of studies of soil processes and soil biota in arid ecosystems. In decomposition and mineralization processes, there is a temporal succession of microarthropod and nematode species. Tydeid mit...

  15. A conodont-based Middle Triassic age assignment for the Luoping Biota of Yunnan, China

    Institute of Scientific and Technical Information of China (English)

    ZHANG QiYue; ZHOU ChangYong; LU Tao; XIE Tao; LOU XiongYing; LIU Wei; SUN YuanYuan; HUANG JinYuan; ZHAO LaiShi

    2009-01-01

    The Luoping Biota consists of abundant and well-preserved marine fishes, reptiles, Invertebrates, and plants. It occurs in the Middle Triassic Guanling Formation in Daaozi Village of Luoping County, Yun-nan Province, China. Based on conodonts, the Luoping Biota is determined to lie within the Nicoraella kockeli Zone, which is assigned to the Pelsonian substage of the Anisian.

  16. Soil biota community structure and abundance under agricultural intensification and extensification

    NARCIS (Netherlands)

    Postma-Blaauw, M.B.; Goede, de R.G.M.; Bloem, J.; Faber, J.H.; Brussaard, L.

    2010-01-01

    Understanding the impacts of agricultural intensification and extensification on soil biota communities is useful in order to preserve and restore biological diversity in agricultural soils and enhance the role of soil biota in agroecosystem functioning. Over four consecutive years, we investigated

  17. Population Dynamics of Biota on the Roots of Azolla microphylla Kaulfuss

    Directory of Open Access Journals (Sweden)

    NITA ETIKAWATI

    2000-01-01

    Full Text Available Azolla was a special fern that their associations with Anabaena azollae able to fix free nitrogen from air, to produce protein. Although by the ages, biota diversity those habits on the roots of Azolla increased and effected to protein concentration. The research was to find out population dynamics of biota on the roots of Azolla microphylla Kaulfuss and the growth peak. This study used Completely Randomized Design with 10 kinds of biota, i.e. bacteria, Fungi, Actinomycetes, Protozoa, Alga, Crustacean, Rotifers, Coelenterate, Insect and Molluscs, and it was used 3 replications. Research was conducted within 4 weeks and the populations of biota were observed every week. Data were statistically analyzed using Analysis Variant and Duncan’s Multiple Range Test. The population dynamics of biota on the roots of Azolla microphylla Kaulfuss were influenced on its quantity and composition, and the growth peak is done in 2nd week.

  18. Pu-239 organ specific dosimetric model applied to non-human biota

    Science.gov (United States)

    Kaspar, Matthew Jason

    There are few locations throughout the world, like the Maralinga nuclear test site located in south western Australia, where sufficient plutonium contaminate concentration levels exist that they can be utilized for studies of the long-term radionuclide accumulation in non-human biota. The information obtained will be useful for the potential human users of the site while also keeping with international efforts to better understand doses to non-human biota. In particular, this study focuses primarily on a rabbit sample set collected from the population located within the site. Our approach is intended to employ the same dose and dose rate methods selected by the International Commission on Radiological Protection and adapted by the scientific community for similar research questions. These models rely on a series of simplifying assumptions on biota and their geometry; in particular; organisms are treated as spherical and ellipsoidal representations displaying the animal mass and volume. These simplifications assume homogeneity of all animal tissues. In collaborative efforts between Colorado State University and the Australian Nuclear Science and Technology Organisation (ANSTO), we are expanding current knowledge on radionuclide accumulation in specific organs causing organ-specific dose rates, such as Pu-239 accumulating in bone, liver, and lungs. Organ-specific dose models have been developed for humans; however, little has been developed for the dose assessment to biota, in particular rabbits. This study will determine if it is scientifically valid to use standard software, in particular ERICA Tool, as a means to determine organ-specific dosimetry due to Pu-239 accumulation in organs. ERICA Tool is normally applied to whole organisms as a means to determine radiological risk to whole ecosystems. We will focus on the aquatic model within ERICA Tool, as animal organs, like aquatic organisms, can be assumed to lie within an infinite uniform medium. This model would

  19. Increasing synchrony of high temperature and low flow in western North American streams: double trouble for coldwater biota?

    Science.gov (United States)

    Arismendi, Ivan; Safeeq, Mohammad; Johnson, Sherri L.; Dunham, Jason B.; Haggerty, Roy

    2013-01-01

    Flow and temperature are strongly linked environmental factors driving ecosystem processes in streams. Stream temperature maxima (Tmax_w) and stream flow minima (Qmin) can create periods of stress for aquatic organisms. In mountainous areas, such as western North America, recent shifts toward an earlier spring peak flow and decreases in low flow during summer/fall have been reported. We hypothesized that an earlier peak flow could be shifting the timing of low flow and leading to a decrease in the interval between Tmax_w and Qmin. We also examined if years with extreme low Qmin were associated with years of extreme high Tmax_w. We tested these hypotheses using long32 term data from 22 minimally human-influenced streams for the period 1950-2010. We found trends toward a shorter time lag between Tmax_w and Qmin over time and a strong negative association between their magnitudes. Our findings show that aquatic biota may be increasingly experiencing narrower time windows to recover or adapt between these extreme events of low flow and high temperature. This study highlights the importance of evaluating multiple environmental drivers to better gauge the effects of the recent climate variability in freshwaters.

  20. Compartmentalisation Strategies for Hydrocarbon-based Biota on Titan

    Science.gov (United States)

    Norman, L.; Fortes, A. D.; Skipper, N.; Crawford, I.

    2013-05-01

    The goal of our study is to determine the nature of compartimentalisation strategies for any organisms inhabiting the hydrocarbon lakes of Titan (the largest moon of Saturn). Since receiving huge amounts of data via the Cassini-Huygens mission to the Saturnian system astrobiologists have speculated that exotic biota might currently inhabit this environment. The biota have been theorized to consume acetylene and hydrogen whilst excreting methane (1,2) leading to an anomalous hydrogen depletion near the surface; and there has been evidence to suggest this depletion exists (3). Nevertheless, many questions still remain concerning the possible physiological traits of biota in these environments, including whether cell-like structures can form in low temperature, low molecular weight hydrocarbons. The backbone of terrestrial cell membranes are vesicular structures composed primarily of a phospholipid bilayer with the hydrophilic head groups arranged around the periphery and are thought to be akin to the first protocells that terrestrial life utilised (4). It my be possible that reverse vesicles composed of a bilayer with the hydrophilic head groups arranged internally and a nonpolar core may be ideal model cell membranes for hydrocarbon-based organisms inhabiting Titan's hydrocarbon lakes (5). A variety of different surfactants have been used to create reverse vesicles in nonpolar liquids to date including; non-ionic ethers (7) and esters (6, 8); catanionic surfactant mixtures (9); zwitterionic gemini surfactants (10); coblock polymer surfactants (11); and zwitterionic phospholipid surfactants (12). In order to discover whether certain phospholipids can exhibit vesicular behaviour within hydrocarbon liquids, and to analyse their structure, we have carried out experimental studies using environmental conditions that are increasing comparable to those found on the surface of Titan. Experimental methods that have been used to determine the presence of vesicles include the

  1. Biological Sampling and Analysis in Sinclair and Dyes Inlets, Washington: Chemical Analyses for 2007 Puget Sound Biota Study

    Energy Technology Data Exchange (ETDEWEB)

    Brandenberger, Jill M.; Suslick, Carolynn R.; Johnston, Robert K.

    2008-10-09

    Evaluating spatial and temporal trends in contaminant residues in Puget Sound fish and macroinvertebrates are the objectives of the Puget Sound Ambient Monitoring Program (PSAMP). In a cooperative effort between the ENVironmental inVESTment group (ENVVEST) and Washington State Department of Fish and Wildlife, additional biota samples were collected during the 2007 PSAMP biota survey and analyzed for chemical residues and stable isotopes of carbon (δ13C) and nitrogen (δ15N). Approximately three specimens of each species collected from Sinclair Inlet, Georgia Basin, and reference locations in Puget Sound were selected for whole body chemical analysis. The muscle tissue of specimens selected for chemical analyses were also analyzed for δ13C and δ15N to provide information on relative trophic level and food sources. This data report summarizes the chemical residues for the 2007 PSAMP fish and macro-invertebrate samples. In addition, six Spiny Dogfish (Squalus acanthias) samples were necropsied to evaluate chemical residue of various parts of the fish (digestive tract, liver, embryo, muscle tissue), as well as, a weight proportional whole body composite (WBWC). Whole organisms were homogenized and analyzed for silver, arsenic, cadmium, chromium, copper, nickel, lead, zinc, mercury, 19 polychlorinated biphenyl (PCB) congeners, PCB homologues, percent moisture, percent lipids, δ13C, and δ15N.

  2. Native Freshwater Fish and Mussel Species Richness

    Data.gov (United States)

    U.S. Environmental Protection Agency — These data represent predicted current distributions of all native freshwater fish and freshwater mussels in the Middle-Atlantic region. The data are available for...

  3. The Cretaceous Tetori biota in Japan and its evolutionary significance for terrestrial ecosystems in Asia

    Science.gov (United States)

    Matsukawa, M.; Ito, M.; Nishida, N.; Koarai, K.; Lockley, M.G.; Nichols, D.J.

    2006-01-01

    Cretaceous nonmarine deposits are widely distributed on the Asian continent and include various kinds of zoo- and phyto-assemblages. The Tetori Group is one of the most important Mesozoic terrestrial deposits in East Asia, and for this reason its geology, stratigraphy, and biota have been studied intensively by our group for more than a decade. We present the main results herein. We confirm that formations as lithostratigraphic units are the best geological correlation tools for the Tetori Group and the best tools for a geological mapping of the group. Although subgroups have previously been used for correlation, proper designation and evaluation of subgroups is required if they are to be used effectively, and we show that previous geological correlation of the Tetori Group has been confused by inappropriate definition of these subgroups. We located fossil localities including reported zoo- and phyto-assemblages in the framework of formations correlated by our stratigraphy. The occurrence of zoo-assemblages was probably controlled by environments (i.e., most are in situ), but phyto-assemblages were mostly transported and rapidly buried by high-energy river systems. Although two distinct dinosaur faunas and four floras have been named for the zoo- and phyto-assemblages in the Tetori Group, in reality there is only one Tetori Dinosaur Fauna and one Tetori Flora, as proved by careful correlation. Two types of zoo-assemblages co-occur in the Tetori Group: vertebrate species whose ancestors flourished in the Jurassic (as found in China), and their descendants from the Late Cretaceous. As the latter modern type of assemblage is more abundant than the former, changeable environments at the continental margin probably accelerated evolution of more modern species. We can employ nonmarine molluscan species as geological correlation tools in some cases, i.e., when their taxon ranges are well-confirmed by independent evidence. However, because freshwater molluscan species and

  4. Spatial and temporal trends of contaminants in terrestrial biota from the Canadian Arctic

    International Nuclear Information System (INIS)

    Contaminants in the Canadian Arctic have been studied over the last twelve years under the guidance of the Northern Contaminants Program. This paper summarizes results from that program from 1998 to 2003 with respect to terrestrial animals in the Canadian Arctic. The arctic terrestrial environment has few significant contaminant issues, particularly when compared with freshwater and marine environments. Both current and historical industrial activities in the north may have a continuing effect on biota in the immediate area, but effects tend to be localized. An investigation of arctic ground squirrels at a site in the Northwest Territories that had historically received applications of DDT concluded that DDT in arctic ground squirrels livers was the result of contamination and that this is an indication of the continuing effect of a local point source of DDT. Arsenic concentrations were higher in berries collected from areas around gold mines in the Northwest Territories than from control sites, suggesting that gold mining may significantly affect arsenic levels in berries in the Yellowknives Dene traditional territory. Although moose and caribou from the Canadian Arctic generally carry relatively low contaminant burdens, Yukon moose had high renal selenium concentrations, and moose and some woodland caribou from the same area had high renal cadmium levels, which may put some animals at risk of toxicological effects. Low hepatic copper levels in some caribou herds may indicate a shortage of copper for metabolic demands, particularly for females. Similarities in patterns of temporal fluctuations in renal element concentrations for moose and caribou suggest that environmental factors may be a major cause of fluctuations in renal concentrations of some elements. Concentrations of persistent organochlorines and metals in beaver and muskrat from the Northwest Territories, and carnivores from across the Canadian Arctic were very low and considered normal for terrestrial

  5. Footprints of climate change on Mediterranean Sea biota

    Directory of Open Access Journals (Sweden)

    Núria eMarbà

    2015-08-01

    Full Text Available The Mediterranean Sea ranks among the ocean regions warming fastest. There is evidence for impacts of climate change on marine Mediterranean organisms but a quantitative assessment is lacking. We compiled the impacts of warming reported in the literature to provide a quantitative assessment for the Mediterranean Sea. During the last three decades the summer surface temperature has increased 1.15 oC. Strong heat wave events have occurred in years 1994, 2003 and 2009. Impacts of warming are evident on growth, survival, fertility, migration and phenology of pelagic and benthic organisms, from phytoplankton to marine vegetation, invertebrates and vertebrates. Overall, 50 % of biological impacts in the Mediterranean Sea occur at summer surface temperature anomaly ≤ 4.5 ºC and at summer surface temperature of 27.5 ºC. The activation energy (geometric mean 1.58 ± 0.48 eV, the slope of the Arrhenius equation describing the temperature-dependence of biological processes, for the response of Mediterranean marine biota to warming reveals that these responses in the Mediterranean are far steepest than possibly explained by the direct effect of warming alone. The observations are biased toward the northern and western sectors of the basin, likely underestimating the impacts of warming in areas where warming is particularly intense.

  6. Footprints of climate change on Mediterranean Sea biota

    KAUST Repository

    Marbà, Núria

    2015-08-13

    The Mediterranean Sea ranks among the ocean regions warming fastest. There is evidence for impacts of climate change on marine Mediterranean organisms but a quantitative assessment is lacking. We compiled the impacts of warming reported in the literature to provide a quantitative assessment for the Mediterranean Sea. During the last three decades the summer surface temperature has increased 1.15°C. Strong heat wave events have occurred in years 1994, 2003, and 2009. Impacts of warming are evident on growth, survival, fertility, migration and phenology of pelagic and benthic organisms, from phytoplankton to marine vegetation, invertebrates and vertebrates. Overall, 50% of biological impacts in the Mediterranean Sea occur at summer surface temperature anomaly ≤ 4.5°C and at summer surface temperature of 27.5°C. The activation energy (geometric mean 1.58 ± 0.48 eV), the slope of the Arrhenius equation describing the temperature-dependence of biological processes, for the response of Mediterranean marine biota to warming reveals that these responses in the Mediterranean are far steepest than possibly explained by the direct effect of warming alone. The observations are biased toward the northern and western sectors of the basin, likely underestimating the impacts of warming in areas where warming is particularly intense.

  7. Organophosphorous flame retardants in biota from Svalbard, Norway.

    Science.gov (United States)

    Hallanger, Ingeborg G; Sagerup, Kjetil; Evenset, Anita; Kovacs, Kit M; Leonards, Pim; Fuglei, Eva; Routti, Heli; Aars, Jon; Strøm, Hallvard; Lydersen, Christian; Gabrielsen, Geir Wing

    2015-12-15

    Eight arctic species, including fish, birds and mammals, from diverse habitats (marine and terrestrial) within the Svalbard Archipelago, Norway, were screened for 14 organophosphorus flame retardant (PFR) compounds. Ten PFRs were detected: tris(2-chloroethyl)phosphate (TCEP), tris(2-chloroisopropyl)phosphate (TCIPP), tris(1,3-dichloro-2-propyl)phosphate (TDCIPP), triphenyl phosphate (TPHP); 2-ethylhexyl diphenyl phosphate (EHDPP); tris(2-butoxyethyl)phosphate (TBOEP); tritolyl phosphate (TCrP); triisobutyl phosphate (TIBP); tris(2-ethylhexyl)phosphate (TEHP); and butyl diphenyl phosphate (DPhBP). The greatest number of different PFR compounds, and the highest detection frequency were measured in capelin (Mallotus villotus), and the lowest in Brünnich's guillemot (Uria lomvia). The highest concentrations of ΣPFR, as well as the highest concentration of a single PFR compound, TBOEP, were measured in arctic fox (Vulpes lagopus). The presence of PFR compounds in arctic biota indicates that these compounds can undergo long-range transport and are, to some degree, persistent and bioaccumulated. The potential for biomagnification from fish to higher trophic levels seems to be limited. PMID:26453403

  8. Arctic freshwater export: Status, mechanisms, and prospects

    NARCIS (Netherlands)

    Haine, T.W.N.; Curry, B.; Gerdes, R.; Hansen, E.; Karcher, M.; Lee, C.; Rudels, B.; Spreen, G.; de Steur, L.; Stewart, K.D.; Woodgate, R.

    2015-01-01

    Large freshwater anomalies clearly exist in the Arctic Ocean. For example, liquid freshwater has accumulated in the Beaufort Gyre in the decade of the 2000s compared to 1980–2000, with an extra ˜ 5000 km3 — about 25% — being stored. The sources of freshwater to the Arctic from precipitation and runo

  9. Nearctic freshwater tardigrades: a review

    Directory of Open Access Journals (Sweden)

    Juliana G. HINTON

    2007-09-01

    Full Text Available The distribution and ecology of limno-terrestrial Tardigrada in the Nearctic realm remain poorly known. This is especially true of freshwater tardigrades (i.e., species found in permanently submerged habitats, which have received much less attention than terrestrial species. We reviewed the literature on Nearctic freshwater tardigrades. Of 204 Nearctic limno-terrestrial tardigrade species, 44 have been collected from sediments and aquatic vegetation of streams, rivers, ponds, lakes, groundwater and cryoconite holes. Of these, 17 are hydrophilous species found exclusively or primarily in aquatic environments. Most of the remainder are probably washed in accidentally from terrestrial substrates. Among the hydrophilous species, five are endemic to the Nearctic realm and three cosmopolitan. Hypsibius dujardini is the most widely-distributed hydrophilous species. There are no regional collections of Nearctic freshwater tardigrades comparable to those for terrestrial species. Aquatic tardigrades are benthic, and are found in sediments and on aquatic vegetation. Hypsibius dujardini and other widespread species are found in both substrates, and there is thus no evidence of substrate specificity. Numerically, tardigrades usually comprise a minor component of benthic invertebrate communities. Nothing is known of their trophic relationships or dispersal in these habitats. The density of Nearctic freshwater tardigrade species peaks in the spring and/or fall. Future research should increase the spatial and temporal scale of study, and employ adequate replication.

  10. Dynamic modelling of radionuclide uptake by Fukushima coastal biota - Dynamic modelling of radionuclide uptake by marine biota: application to Fukushima assessment

    Energy Technology Data Exchange (ETDEWEB)

    Vives i Batlle, Jordi [Belgian Nuclear Research Centre, Boeretang 200, 2400 Mol (Belgium)

    2014-07-01

    Radiological assessments to non-human marine biota are usually carried out by assuming that the activity concentration in an organism is proportional to the activity concentration in an adjacent volume of water, via a concentration factor (CF). It is also assumed that radionuclides in the water are in isotopic equilibrium with the sediments via a sediment distribution coefficient (K{sub d}). These assumptions are not valid in accidental situations where the biota and the sediments react with a time delay to large variations of activity concentration in seawater. A simple dynamic model was developed to factorise the dynamics of radionuclide uptake and turnover in biota and sediments, as determined by a balance between the residence time of radionuclides in seawater/sediments and the biological half-life of elimination in the biota. The model calculates activity concentration of {sup 131}I, {sup 134}Cs, {sup 137}Cs and {sup 90}Sr in seabed sediment, fish, crustaceans, molluscs and macro-algae from surrounding activity concentrations in seawater, with which to derive internal and external dose rates. A central element of this new model is the inclusion of sediment processes in dynamic transfer modelling. The model is adapted to include depletion of radionuclides adsorbed onto suspended particulates (particle scavenging), molecular diffusion, pore water mixing and bioturbation (modelled effectively as a diffusive process) represented by a simple set of differential equations that is coupled with the biological uptake/turnover processes. In this way, the model is capable of reproducing activity concentration in sediment to give a more realistic calculation of the external dose to biota compared with the simpler approach based on CF and K{sub d} values used in previous assessments. The model is applied to the assessment of the radiological impact of the Fukushima accident on marine biota in the early phase of the accident. It is shown that previous assessment of the

  11. Evaluating Alternative Strategies for Investments in Freshwater Conservation

    Science.gov (United States)

    Cheruvelil, K. S.; Kramer, D. B.; Zhang, T.; Ligmann-Zielinska, A.; Soranno, P.; Bremigan, M. T.

    2012-12-01

    Efforts towards systematic conservation planning for freshwaters have progressed far less than similar efforts in the terrestrial and marine environments. Although there are differences in the coupled human and natural systems that distinguish freshwater, terrestrial, and marine environments, many of the tools that have been used in terrestrial and marine systems can also be used for conservation planning for freshwater resources. In this paper, we used one such tool, return on investment (ROI), to identify optimal conservation portfolios. Our overarching research question is: how do different strategies for evaluating ROI benefits influence the resulting portfolio and the outcome of interest - in our case, water quality? Specifically, we examined investments to convert farmed agricultural land to fallow land to improve water quality in 55 inland lakes in southwestern Michigan. We simulated investments and compared the ROIs for the following strategies: 1) economic; 2) ecological; 3) environmental policy and 4) agricultural policy. We also tested the well-established assumption that riparian lands, those abutting and within 30 m of freshwater shorelines, have the greatest potential to influence water quality. We found that 1) investments in freshwater resources through the conservation of riparian land are more effective than the conservation of randomly selected parcels of similar land area in the catchment; 2) the costs and benefits of riparian land conservation vary considerably among lakes; 3) the choice of investment strategies results in very different conservation portfolios; 4) the resulting conservation portfolios have very different distributional and policy implications. These analyses and results provide a foundation on which to improve systematic conservation planning for freshwaters.

  12. Metals in New Jersey's Pinelands National Reserve Sediments, Surface Water and Biota: An Emphasis on Mercury

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Technical data on the nature and extent of chemical contaminants in sediments and biota of the streams comprising the Pinelands National Reserve (Pinelands) in New...

  13. Survey of contaminants in soils and biota at the Seney National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — A survey was conducted in 1987 to assess the presence and degree of contamination in soils and various biota at Seney National Wildlife Refuge, located in the...

  14. Evaluation of clean-up agents for total petroleum hydrocarbon analysis in biota and sediments.

    NARCIS (Netherlands)

    Muijs, B.; Jonker, M.T.O.

    2009-01-01

    Petroleum hydrocarbons (oil) are common environmental contaminants. For risk assessment purposes, their concentrations in environmental matrixes, such as biota and soils/sediments are frequently determined by solvent extraction and subsequent analysis with gas chromatography (GC) equipped with flame

  15. Effects of inter-row management intensity on wild bee, plant and soil biota diversity in vineyards

    Science.gov (United States)

    Kratschmer, Sophie; Pachinger, Bärbel; Winter, Silvia; Zaller, Johann G.; Buchholz, Jacob; Querner, Pascal; Strauß, Peter; Bauer, Thomas; Stiper, Katrin

    2016-04-01

    Vineyards may provide a range of essential ecosystem services, which interact with a diverse community of above- and belowground organisms. Intensive soil management like frequent tilling has resulted in the degradation of habitat quality with consequences on biodiversity and ecosystem services. This study is part of the European BiodivERsA project "VineDivers - Biodiversity-based ecosystem services in vineyards". We study the effects of different soil management intensities on above- and below-ground biodiversity (plants, insect pollinators, and soil biota), their interactions and the consequences for ecosystem services. We investigated 16 vineyards in Austria assessing the diversity of (1) wild bees using a semi-quantitative transect method, (2) earthworms by hand sorting, (3) Collembola (springtails) via pitfall trapping and soil coring, (4) plants by relevés and (5) litter decomposition (tea bag method). Management intensity differed in tillage frequency from intermediate intensity resulting in temporary vegetation cover to no tillage in permanent vegetation cover systems. First results show opposed relationships between the biodiversity of selected species groups and management intensity. We will discuss possible explanations and evaluate ecological interactions between wild bee, plant and soil biota diversity.

  16. Marine biota sightings during 3D marine seismic surveys

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Joao Luiz Martinez de; Uller, George A. [CGG do Brasil, Rio de Janeiro, RJ (Brazil); Derntl, Jose Renato; Ribeiro, Camila Castroviejo da Silva; Pereira, Edisio [GEOCOOP Cooperativa de Trabalho, Rio de Janeiro, RJ (Brazil); Miranda, Cristina Maschio de [Nautilus Cooperativa de Trabalho (Brazil); Ferraz, Alexandre Almeida; Costa, Leandro Damiao Soares da [Okeanos Consultoria e Meio Ambiente Ltda. (Brazil)

    2004-07-01

    This work intends to make a correlation between the presence of the marine biota and the seismic source activity (air guns) during seismic surveys, in Campos (BM-C-25 and BM-C-16) and Santos (BM-S-3) Basin, since July 2003 until March 2004. Environmental data were acquired onboard of the Seismic Vessel CGG Harmattan by a team of four oceanographers (environmental technicians), working on the highest place of the Vessel to record and identify the animals whenever was possible. The data were recorded in forms where fields about the biotic and environmental aspects were filled. In 212 days of observations, 2580,1 hours of sighting's effort were recorded; the air guns worked during 37,6% of the time of the effort. These efforts were made during the daylight reaching an average value of 11,35 hours/day. Sightings were divided into the suborders Odontocetes and Mysticetes, and others (fishes, turtles and non identified mammals). 175 sightings were recorded, being 54% when the air gun was off (24% Mysticetes, 56% Odontocetes, 20% others). Similarly, when the air gun was working, 46% of the records were made (24% Mysticetes, 61% Odontocetes, 6% others); the major concentration (58%) of individuals was inside the 1000 m radius around the ship, followed by 14% of the individuals occurring between 3001-4000 m radius away from the ship. The analysis of the data suggests a non-evasive behavior related to the working of the seismic source, corroborating the results reached by other publications using the data collected onboard CGG Vessels. (author)

  17. Natural radioactivity in some specimens of the marine biota

    International Nuclear Information System (INIS)

    Marine environment contamination by natural radionuclides (uranium and 238U daughters) is evaluated using marine -fauna and flora elements concentrating fission - and radioactivated products released by nuclear facilities. Total alpha and beta radiometry is done in the the biota to determine the radionuclide concentration. Uranium, 226Ra and 210PO assay is done to estimate their contribution to natural radioactivity in the chosen biological indicators. Several analytical techniques required by each radionuclide are used. Potassium assay is done to evaluate the contribution of 40K to the natural radioactivity, and calcium assay to determine Ra/Ca and U/Ca ratios in the samples. For total alpha radiometry in algae the higher average value is detected in Phaeophyta (84.1 pCi/kg fresh weight); maximum concentration in animals is registered in Bunodosoma caissarum (43.1 pCi/kg fresh weight). For algae, the higher average total beta radiometry detected is in Chlorophyta (6.9 nCi/kg fresh weight); the maximum value found in animals refers to Thais Haemastoma (7.54 nCi/kg fresh weight). Potassium higher average ratio for algae occurs in Chlorophyta (12.77% ashes); for animals, the maximum value is found in Bunodosoma caissarum (13.80% ashes). The uranium concentration factor is maximum in Perna perna bissus (684) while the minimum is registered in Thais haemastoma and Sargassum vulgare (44). The 226Ra concentration factor is maximum in Sargassum vulgare (2143) and minimum in Bunodosoma caissarum (32). Maximum average ratio for 210PO in algae occurs in Phaephyta (11.5 pCi/g dry weight) and the maximum concentration for animals in Perna perna (31.5 pCi/g dry weight). The techniques employed proved to be efficient for the objectives aimed at. (Author)

  18. Bacterial biota in reflux esophagitis and Barrett's esophagus

    Institute of Scientific and Technical Information of China (English)

    Zhiheng Pei; Liying Yang; Richard M Peek; Jr Steven M Levine; David T Pride; Martin J Blaser

    2005-01-01

    AIM: To identify the bacterial flora in conditions such as Barrett's esophagus and reflux esophagitis to determine if they are similar to normal esophageal flora.METHODS: Using broad-range 16S rDNA PCR,esophageal biopsies were examined from 24 patients [9with normal esophageal mucosa, 12 with gastroesophageal reflux disease (GERD), and 3 with Barrett's esophagus].Two separate broad-range PCR reactions were performed for each patient, and the resulting products were cloned.In one patient with Barrett's esophagus, g9 PCR clones were analyzed.RESULTS: Two separate clones were recovered from each patient (total = 48), representing 24 different species, with 14 species homologous to known bacteria,5 homologous to unidentified bacteria, and 5 were not homologous (<97% identity) to any known bacterial 16S rDNA sequences. Seventeen species were found in the reflux esophagitis patients, 5 in the Barrett's esophagus patients, and 10 in normal esophagus patients.Further analysis concentrating on a single biopsy from an individual with Barrett's esophagus revealed the presence of 21. distinct bacterial species. Members of four phyla were represented, including Bacteroidetes,Firmicutes, Proteobacteria, and Actinobacteria.Microscopic examination of each biopsy demonstrated bacteria in intimate association with the distal esophageal epithelium, suggesting that the presence of these bacteria is not transitory.CONCLUSION: These findings provide evidence for a complex, residential bacterial population in esophageal reflux-related disorders. While much of this biota is present in the normal esophagus, more detailed comparisons may help identify potential disease associations.

  19. Making sense of ocean biota: How evolution and biodiversity of land organisms differ from that of the plankton

    Indian Academy of Sciences (India)

    Victor Smetacek

    2012-09-01

    The oceans cover 70% of the planet’s surface, and their planktonic inhabitants generate about half the global primary production, thereby playing a key role in modulating planetary climate via the carbon cycle. The ocean biota have been under scientific scrutiny for well over a century, and yet our understanding of the processes driving natural selection in the pelagic environment – the open water inhabited by drifting plankton and free-swimming nekton – is still quite vague. Because of the fundamental differences in the physical environment, pelagic ecosystems function differently from the familiar terrestrial ecosystems of which we are a part. Natural selection creates biodiversity but understanding how this quality control of randommutations operates in the oceans − which traits are selected for under what circumstances and by which environmental factors, whether bottom-up or top-down − is currently a major challenge. Rapid advances in genomics are providing information, particularly in the prokaryotic realm, pertaining not only to the biodiversity inventory but also functional groups. This essay is dedicated to the poorly understood tribes of planktonic protists (unicellular eukaryotes) that feed the ocean’s animals and continue to run the elemental cycles of our planet. It is an attempt at developing a conceptually coherent framework to understand the course of evolution by natural selection in the plankton and contrast it with the better-known terrestrial realm. I argue that organism interactions, in particular co-evolution between predators and prey (the arms race), play a central role in driving evolution in the pelagic realm. Understanding the evolutionary forces shaping ocean biota is a prerequisite for harnessing plankton for human purposes and also for protecting the oceanic ecosystems currently under severe stress from anthropogenic pressures.

  20. Making sense of ocean biota: how evolution and biodiversity of land organisms differ from that of the plankton.

    Science.gov (United States)

    Smetacek, Victor

    2012-09-01

    The oceans cover 70% of the planet's surface, and their planktonic inhabitants generate about half the global primary production, thereby playing a key role in modulating planetary climate via the carbon cycle. The ocean biota have been under scientific scrutiny for well over a century, and yet our understanding of the processes driving natural selection in the pelagic environment - the open water inhabited by drifting plankton and free-swimming nekton - is still quite vague. Because of the fundamental differences in the physical environment, pelagic ecosystems function differently from the familiar terrestrial ecosystems of which we are a part. Natural selection creates biodiversity but understanding how this quality control of random mutations operates in the oceans - which traits are selected for under what circumstances and by which environmental factors, whether bottom-up or top-down - is currently a major challenge. Rapid advances in genomics are providing information, particularly in the prokaryotic realm, pertaining not only to the biodiversity inventory but also functional groups. This essay is dedicated to the poorly understood tribes of planktonic protists (unicellular eukaryotes) that feed the ocean's animals and continue to run the elemental cycles of our planet. It is an attempt at developing a conceptually coherent framework to understand the course of evolution by natural selection in the plankton and contrast it with the better-known terrestrial realm. I argue that organism interactions, in particular co-evolution between predators and prey (the arms race), play a central role in driving evolution in the pelagic realm. Understanding the evolutionary forces shaping ocean biota is a prerequisite for harnessing plankton for human purposes and also for protecting the oceanic ecosystems currently under severe stress from anthropogenic pressures. PMID:22922185

  1. The estimation of absorbed dose rates for non-human biota : an extended inter-comparison.

    Energy Technology Data Exchange (ETDEWEB)

    Batlle, J. V. I.; Beaugelin-Seiller, K.; Beresford, N. A.; Copplestone, D.; Horyna, J.; Hosseini, A.; Johansen, M.; Kamboj, S.; Keum, D.-K.; Kurosawa, N.; Newsome, L.; Olyslaegers, G.; Vandenhove, H.; Ryufuku, S.; Lynch, S. V.; Wood, M. D.; Yu, C. (Environmental Science Division); (Westlakes Scientific Consulting Ltd.); (Inst. de Radioprotection et de Surete Nucleaire); (Centre for Ecology & Hydrology); (Norwegian Radiation Protection Authority); (State Office for Nuclear Safety); (Korea Atomic Energy Research Institute); (Visible Information Centre Inc.); (Belgian Nuclear Research Centre); (University of Liverpool)

    2011-05-01

    An exercise to compare 10 approaches for the calculation of unweighted whole-body absorbed dose rates was conducted for 74 radionuclides and five of the ICRP's Reference Animals and Plants, or RAPs (duck, frog, flatfish egg, rat and elongated earthworm), selected for this exercise to cover a range of body sizes, dimensions and exposure scenarios. Results were analysed using a non-parametric method requiring no specific hypotheses about the statistical distribution of data. The obtained unweighted absorbed dose rates for internal exposure compare well between the different approaches, with 70% of the results falling within a range of variation of {+-}20%. The variation is greater for external exposure, although 90% of the estimates are within an order of magnitude of one another. There are some discernible patterns where specific models over- or under-predicted. These are explained based on the methodological differences including number of daughter products included in the calculation of dose rate for a parent nuclide; source-target geometry; databases for discrete energy and yield of radionuclides; rounding errors in integration algorithms; and intrinsic differences in calculation methods. For certain radionuclides, these factors combine to generate systematic variations between approaches. Overall, the technique chosen to interpret the data enabled methodological differences in dosimetry calculations to be quantified and compared, allowing the identification of common issues between different approaches and providing greater assurance on the fundamental dose conversion coefficient approaches used in available models for assessing radiological effects to biota.

  2. The estimation of absorbed dose rates for non-human biota: an extended intercomparison.

    Science.gov (United States)

    Vives i Batlle, J; Beaugelin-Seiller, K; Beresford, N A; Copplestone, D; Horyna, J; Hosseini, A; Johansen, M; Kamboj, S; Keum, D-K; Kurosawa, N; Newsome, L; Olyslaegers, G; Vandenhove, H; Ryufuku, S; Vives Lynch, S; Wood, M D; Yu, C

    2011-05-01

    An exercise to compare 10 approaches for the calculation of unweighted whole-body absorbed dose rates was conducted for 74 radionuclides and five of the ICRP's Reference Animals and Plants, or RAPs (duck, frog, flatfish egg, rat and elongated earthworm), selected for this exercise to cover a range of body sizes, dimensions and exposure scenarios. Results were analysed using a non-parametric method requiring no specific hypotheses about the statistical distribution of data. The obtained unweighted absorbed dose rates for internal exposure compare well between the different approaches, with 70% of the results falling within a range of variation of ±20%. The variation is greater for external exposure, although 90% of the estimates are within an order of magnitude of one another. There are some discernible patterns where specific models over- or under-predicted. These are explained based on the methodological differences including number of daughter products included in the calculation of dose rate for a parent nuclide; source-target geometry; databases for discrete energy and yield of radionuclides; rounding errors in integration algorithms; and intrinsic differences in calculation methods. For certain radionuclides, these factors combine to generate systematic variations between approaches. Overall, the technique chosen to interpret the data enabled methodological differences in dosimetry calculations to be quantified and compared, allowing the identification of common issues between different approaches and providing greater assurance on the fundamental dose conversion coefficient approaches used in available models for assessing radiological effects to biota. PMID:21113609

  3. Literature Review and Database of Relations Between Salinity and Aquatic Biota: Applications to Bowdoin National Wildlife Refuge, Montana

    Science.gov (United States)

    Gleason, Robert A.; Tangen, Brian A.; Laubhan, Murray K.; Finocchiaro, Raymond G.; Stamm, John F.

    2009-01-01

    27 data fields that include variables such as taxonomic identification, values for salinity and pH, wetland classification, location of study, and source of data. The databases are not exhaustive of the literature and are biased toward wetland habitats located in the glaciated North-Central United States; however, the databases do encompass a diversity of biota commonly found in brackish and freshwater inland wetland habitats.

  4. Assessment of mercury and methylmercury in water, sediment, and biota in Sulphur Creek in the vicinity of the Clyde Gold Mine and the Elgin Mercury Mine, Colusa County, California

    Science.gov (United States)

    Hothem, Roger L.; Rytuba, James J.; Brussee, Brianne E.; Goldstein, Daniel N.

    2013-01-01

    At the request of the U.S. Bureau of Land Management, we performed a study during April–July 2010 to characterize mercury (Hg), monomethyl mercury (MMeHg), and other geochemical constituents in sediment, water, and biota at the Clyde Gold Mine and the Elgin Mercury Mine, located in neighboring subwatersheds of Sulphur Creek, Colusa County, California. This study was in support of a Comprehensive Environmental Response, Compensation, and Liability Act - Removal Site Investigation. The investigation was in response to an abatement notification from the California Central Valley Regional Water Quality Control Board to evaluate the release of Hg from the Clyde and Elgin mines. Samples of water, sediment, and biota (aquatic macroinvertebrates) were collected from sites upstream and downstream from the two mine sites to evaluate the level of Hg contamination contributed by each mine to the aquatic ecosystem. Physical parameters, as well as dissolved organic carbon, total Hg (HgT), and MMeHg were analyzed in water and sediment. Other relevant geochemical constituents were analyzed in sediment, filtered water, and unfiltered water. Samples of aquatic macroinvertebrates from each mine were analyzed for HgT and MMeHg. The presence of low to moderate concentrations of HgT and MMeHg in water, sediment, and biota from the Freshwater Branch of Sulphur Creek, and the lack of significant increases in these concentrations downstream from the Clyde Mine indicated that this mine is not a significant source of Hg to the watershed during low flow conditions. Although concentrations of HgT and MMeHg were generally higher in samples of sediment and water from the Elgin Mine compared to the Clyde Mine, concentrations in comparable biota from the two mine areas were similar. It is likely that highly saline effluent from nearby hot springs contribute more Hg to the West Fork of Sulphur Creek than the mine waste material at the Elgin Mine.

  5. Cable Bacteria in Freshwater Sediments

    DEFF Research Database (Denmark)

    Risgaard-Petersen, Nils; Kristiansen, Michael; Frederiksen, Rasmus;

    2015-01-01

    In marine sediments cathodic oxygen reduction at the sediment surface can be coupled to anodic sulfide oxidation in deeper anoxic layers through electrical currents mediated by filamentous, multicellular bacteria of the Desulfobulbaceae family, the so-called cable bacteria. Until now, cable...... bacteria have only been reported from marine environments. In this study, we demonstrate that cable bacteria also occur in freshwater sediments. In a first step, homogenized sediment collected from the freshwater stream Giber Å, Denmark, was incubated in the laboratory. After 2 weeks, pH signatures...... marine cable bacteria, with the genus Desulfobulbus as the closest cultured lineage. The results of the present study indicate that electric currents mediated by cable bacteria could be important for the biogeochemistry in many more environments than anticipated thus far and suggest a common evolutionary...

  6. Cross-cutting Perspective Freshwater

    OpenAIRE

    Furusho, C.; Vidaurre, R.; La Jeunesse, I.; M. H. Ramos

    2016-01-01

    One singularity of northwestern Europe (NWE) is that severe droughts are rare events in the region and water scarcity has hardly been experienced in its history. The DROP pilot sites are not exceptions to this context. Although the lack of a drought history in wet areas can explain why drought and water scarcity are not necessarily the focus of (if ever considered in) river basin management plans, it must be noted that freshwater availability for drinking water provision remains a priority st...

  7. Sulfur cycling in freshwater sediments

    Science.gov (United States)

    Klug, M. J.

    1985-01-01

    Organic sulfur containing compounds represent greater than 80% of the total sulfur in sediments of eutrophic freshwater lakes. Although sedimentary sulfur is predominantly in the form of organic compounds, more sulfur is transformed by sulfate reduction than by any other process. Rates of sulfate reduction in these sediments average 7 mmol/sq m/day. This rate is 19 times greater than the net rate of production of inorganic sulfur from organic compounds on an annual basis.

  8. The freshwater reservoir effect in radiocarbon dating

    DEFF Research Database (Denmark)

    Philippsen, Bente

    2013-01-01

    of magnitude and degree of variability of the freshwater reservoir effect over short and long timescales. Radiocarbon dating of recent water samples, aquatic plants, and animals, shows that age differences of up to 2000 14C years can occur within one river. The freshwater reservoir effect has also implications...... for radiocarbon dating of Mesolithic pottery from inland sites of the Ertebølle culture in Northern Germany. The surprisingly old ages of the earliest pottery most probably are caused by a freshwater reservoir effect. In a sediment core from the Limfjord, northern Denmark, the impact of the freshwater reservoir...... effect on radiocarbon dating in an estuarine environment is examined. Here, freshwater influence causes reservoir ages to vary between 250 and 700 14C years during the period 5400 BC - AD 700. The examples in this study show clearly that the freshwater reservoir effect can seriously corrupt radiocarbon...

  9. Bioaccumulation factor of 137Cs in some marine biotas from West Bangka Indonesia

    International Nuclear Information System (INIS)

    Radionuclides may be released from nuclear facilities to the marine environment. Concentrations of radionuclides within marine biotic systems can be influenced by a number of factors, including the type of biota, its source, the radionuclide, and specific characteristics of the sampled specimens and the marine environment (salinity, etc.). The bioconcentration factor for a marine organism is the ratio of the concentration of a radionuclide in that organism to the concentration found in its marine water environment - under conditions of equilibrium. Information on the bioaccumulation of Cs-137 in marine organisms is required to risk assessment evaluates the potential risks to human health. Bioaccumulation of Cs was investigated in marine biota from west Bangka such as Marine cat fish (Arius thalassinus), Baramundi (Lates calcarifer), Mackerel (Scomberomorus commerson), Striped eel catfish (Plotosus lineatus), eel tailed fish (Euristhmus microceps), Yellowtail fusilier (Caesio erythrogaster), Coastal crab (Scylla sp), White shrimp (Penaeus merguiensis) and marine bivalve mollusk (Anadara granosa). Muscle of these marine biota, sediments and water were assayed for Cs-137 by HPGe gamma spectrometer. The bioaccumulation factor for fishes were calculated by ratio of concentration Cs-137 in muscle biota to the its concentration in water. The bioaccumulation factor for mollusks were calculates by ratio of concentration Cs-137 in muscle biota to the its concentration in sediments. The bioaccumulation factor were range 4.99 to 136.34

  10. Bioaccumulation factor of {sup 137}Cs in some marine biotas from West Bangka Indonesia

    Energy Technology Data Exchange (ETDEWEB)

    Suseno, Heny, E-mail: henis@batan.go.id [Radioactive Waste Technology Center - The Indonesia Nuclear Energy Agency (BATAN) (Indonesia)

    2014-03-24

    Radionuclides may be released from nuclear facilities to the marine environment. Concentrations of radionuclides within marine biotic systems can be influenced by a number of factors, including the type of biota, its source, the radionuclide, and specific characteristics of the sampled specimens and the marine environment (salinity, etc.). The bioconcentration factor for a marine organism is the ratio of the concentration of a radionuclide in that organism to the concentration found in its marine water environment - under conditions of equilibrium. Information on the bioaccumulation of Cs-137 in marine organisms is required to risk assessment evaluates the potential risks to human health. Bioaccumulation of Cs was investigated in marine biota from west Bangka such as Marine cat fish (Arius thalassinus), Baramundi (Lates calcarifer), Mackerel (Scomberomorus commerson), Striped eel catfish (Plotosus lineatus), eel tailed fish (Euristhmus microceps), Yellowtail fusilier (Caesio erythrogaster), Coastal crab (Scylla sp), White shrimp (Penaeus merguiensis) and marine bivalve mollusk (Anadara granosa). Muscle of these marine biota, sediments and water were assayed for Cs-137 by HPGe gamma spectrometer. The bioaccumulation factor for fishes were calculated by ratio of concentration Cs-137 in muscle biota to the its concentration in water. The bioaccumulation factor for mollusks were calculates by ratio of concentration Cs-137 in muscle biota to the its concentration in sediments. The bioaccumulation factor were range 4.99 to 136.34.

  11. Impact of tributyltin on antioxidant and DNA damage response in spermatozoa of freshwater prawn Macrobrachium rosenbergii.

    Science.gov (United States)

    Rani, K Umaa; Musthafa, M Saiyad; War, Mehrajuddin; Al-Sadoon, Mohammad K; Paray, Bilal Ahmad; Shareef, T H Mohamed Ahadhu; Nawas, P Mohideen Askar

    2015-12-01

    Effects of tributyltin (TBT) on antioxidant [total superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione reductase (GR)] and DNA damage levels in the spermatozoa were studied and reported here for the first time in the freshwater prawn Macrobrachium rosenbergii. Three groups of (n = 10 in each group) fishes were exposed to three different nominal concentrations of TBT viz., 1, 2, and 4 mg L(-1) along with control group for 90 days. Significant decrease of antioxidant and increased DNA damage levels were seen at higher doses of 2 and 4 mg L(-1). In prawn, the antioxidant level plays a vital role in sperm protection, activation, differential functions related to the physiology, and reproductive behavior. This study serves as a biomonitoring tool to assess the TBT effects on reproductive behavior of aquatic biota.

  12. Radionuclides in biota collected near a dicalcium phosphate plant, southern Catalonia, Spain

    International Nuclear Information System (INIS)

    Industrial waste containing radioactive U-decay series isotopes was released into the Ebro River, Spain, over a period of >20 years from a dicalcium phosphate (DCP) plant. This release raised activities of several natural radionuclides (e.g. 238U, 234U, 230Th, 232Th and 226Ra) in biota taken from the area near the DCP plant. Plants and animals selected for this study included the green algae (Cladophora glomerata), the blue mussel (Mytilus edulis), the zebra mussel (Dreissena polymorpha) and the scavenger catfish (Silurus glanis) because they are all common in the area. Multiple sampling points were chosen for this study: (1) a site in the Riba-Roja Reservoir, above the DCP plant's area of influence, (2) four sites in the area surrounding the DCP plant, close to the town of Flix, and (3) a location in the Ebro Delta Estuary in Fangar Bay. Significant differences in the activities (in Bq kg-1 of dry weight) for the radioisotopes included in this study among samples were attributed to sample location and the species evaluated. For instance, relatively high activities for uranium and radium were obtained in algae collected around the DCP plant, compared to results obtained for algae samples taken from the unimpacted Riba-Roja Reservoir. In contrast, for zebra mussels, enhanced activities were observed for all radionuclides and, in particular, for thorium and radium isotopes within the area of influence. Among catfish samples, activity values from different locations were not significantly different, though slightly higher activities were observed at the sampling point just downstream of the DCP factory. (author)

  13. Comparative food-chain behavior and distribution of actinide elements in and around a contaminated fresh-water pond

    International Nuclear Information System (INIS)

    The bioaccumulation of 233234U, 238U, 238Pu, 239240Pu, 241Am, and 244Cm in both native and introduced biota was studied at Pond 3513, a former low-level radioactive waste settling basin at Oak Ridge National Laboratory. This system, which was decommissioned in 1976 after more than 30 years use, contains approximately 5 Ci of 239240Pu; inventories of other actinide isotopes are considerably less. Significantly higher concentrations of actinides in fish that were allowed access to sediments indicated that sedimentary particulates may be the primary source of transuranics to biota in shallow fresh-water ecosystems. Our study determined habitat, in particular the degree of association of an organism with the sediment-water interface, to be the primary factor in controlling transuranic concentrations in aquatic biota. In most of the biological samples analyzed, excluding samples suspected of being contaminated by sediment, 241Am/239Pu, 244Cm/239Pu, and 238U/239Pu ratios were greater than the respective ratio in sediment while 233234U/238U, and 239240Pu/238Pu ratios were not different from the respective ratios in sediment. The relative uptake of actinides from contaminated sediment by aquatic and terrestrial biota at this site was U > Cm greater than or equal to Am > Pu. The relative extractability of actinides from shoreline sediment was U > Cm approx. = Am > Pu; we also observed the same relative ranking for sediment-water exchange in situ. Concentrations of transuranics in water, terrestrial vegetation, and vertebrate carcasses were less than 10% of the recommended public exposure maximum permissible concentration (MPC) of the ICRP

  14. Freshwater autotrophic picoplankton: a review

    Directory of Open Access Journals (Sweden)

    John G. STOCKNER

    2002-02-01

    Full Text Available Autotrophic picoplankton (APP are distributed worldwide and are ubiquitous in all types of lakes of varying trophic state. APP are major players in carbon production in all aquatic ecosystems, including extreme environments such as cold ice-covered and/or warm tropical lakes and thermal springs. They often form the base of complex microbial food webs, becoming prey for a multitude of protozoan and micro-invertebrate grazers, that effectively channel APP carbon to higher trophic levels including fish. In this review we examine the existing literature on freshwater autotrophic picoplankton, setting recent findings and current ecological issues within an historic framework, and include a description of the occurrence and distribution of both single-cell and colonial APP (picocyanobacteria in different types of lakes. In this review we place considerable emphasis on methodology and ecology, including sampling, counting, preservation, molecular techniques, measurement of photosynthesis, and include extensive comment on their important role in microbial food webs. The model outlined by Stockner of an increase of APP abundance and biomass and a decrease of its relative importance with the increase of phosphorus concentration in lakes has been widely accepted, and only recently confirmed in marine and freshwater ecosystems. Nevertheless the relationship which drives the APP presence and importance in lakes of differing trophic status appears with considerable variation so we must conclude that the success of APP in oligotrophic lakes worldwide is not a certainty but highly probable.

  15. Tidal Freshwater Wetlands: Variation and Changes

    NARCIS (Netherlands)

    Barendregt, A.; Swarth, C.W.

    2013-01-01

    Tidal freshwater wetlands (TFW) are situated in the upper estuary in a zone bordered upstream by the nontidal river and downstream by the oligohaline region. Here, discharge of freshwater from the river and the daily tidal pulse from the sea combine to create conditions where TFW develop. TFW are of

  16. Effects of Pollution on Freshwater Fish.

    Science.gov (United States)

    Brungs, W. A.; And Others

    1978-01-01

    Presents a literature review of the effects of pollution on freshwater fish, covering publications of 1976-77. This review includes: (1) water quality; (2) pesticide pollutants; (3) chemical pollutants; (4) miscellaneous pollutants; and (5) physical factors of pollution on freshwater fish. A list of 338 references is also presented. (HM)

  17. Farming of Freshwater Rainbow Trout in Denmark

    DEFF Research Database (Denmark)

    Jokumsen, Alfred; Svendsen, Lars Moeslund

    Textbook on Farming of Freshwater Rainbow Trout in Denmark. Danish edition with the title: Opdræt af regnbueørred i Danmark......Textbook on Farming of Freshwater Rainbow Trout in Denmark. Danish edition with the title: Opdræt af regnbueørred i Danmark...

  18. Freshwater Ecology. LC Science Tracer Bullet.

    Science.gov (United States)

    Niskern, Diana, Comp.

    Freshwater ecosystems include lakes, ponds, streams, rivers, and certain types of wetlands. This literature and resources guide is not intended to be a comprehensive bibliography on freshwater ecology; the guide is designed--as the name of the series implies--to put the reader or student "on target." Other literature guides related to freshwater…

  19. Using Natural Geochemical Tracers to Discern the Dominant Sources of Freshwater into Biscayne Bay, Southeast Florida

    Science.gov (United States)

    Stalker, J. C.; Price, R. M.; Swart, P. K.

    2005-05-01

    Biscayne Bay is a sub-tropical estuary located on the carbonate platform of south Florida. The water occupying Biscayne Bay is a balance of saltwater influx from the open ocean and freshwater inputs from precipitation, surface water runoff, and submarine groundwater discharge. The bays watershed includes a total of 3 million inhabitants, the major urban centers of Miami and Ft. Lauderdale, as well as the Everglades system. With the development of south Florida, the natural diffuse groundwater and stream flow into the bay has been replaced by a large system of canals and levees in an effort to control flooding and drain swampland. The Comprehensive Everglades Restoration Plan includes changes in the freshwater deliveries to Biscayne Bay from point-source discharges via canals to non-point source discharges via wetlands and groundwater flow. The balance of salinity in Biscayne Bay effects sensitive seagrass and tidal ecosystems including numerous species of corals and other biota. A comprehensive understanding of the flow of freshwater into the bay is crucial to future planned developments and restorations. The goal of this study is to use naturally occurring geochemical constituents as tracers to identify and quantify the sources of freshwater, i.e. rainfall, canal flow, and groundwater, discharge to Biscayne Bay. In this study, discrete samples of precipitation, canal water, terrestrial groundwater, marine groundwater, and bay surface water are collected monthly and analyzed for the stable isotopes of hydrogen and oxygen as well as for major cations and anions. Initial results indicate that fresh groundwater has an isotopic signature (del 18O = -2.66 per mil, del D, -7.60 per mil) similar to rainfall (del 18O = -2.86 per mil, del D =-4.78 per mil). In contrast canal water has a heavy isotopic signature (del 18O = -0.46 per mil, del D = -2.48 per mil) due to evaporation. Thus it is possible to use stable isotopes of oxygen and hydrogen to separate canal water from

  20. Contaminant Assessment of Biota and Sediments in the Albermarle-Pamlico region

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The U.S. Fish and Wildlife Service conducted a baseline contaminants study of the aquatic biota and sediments in the Albemarle-Pamlico region in 1987-88. Sites in...

  1. Dissimilar response of plant and soil biota communities to long-term nutrient adition in grasslands

    NARCIS (Netherlands)

    Wal, van der A.; Geerts, R.H.E.M.; Korevaar, H.; Schouten, A.J.; Jagers op Akkerhuis, G.A.J.M.; Rutgers, M.; Mulder, C.

    2009-01-01

    The long-term effect of fertilizers on plant diversity and productivity is well known, but long-term effects on soil biota communities have received relatively little attention. Here, we used an exceptional long-lasting (>40 years) grassland fertilization experiment to investigate the long-term e

  2. Assessment of doses and risk due to natural radionuclides in edible biota of Domiasiat, Meghalaya.

    Science.gov (United States)

    Kumar, N; Chaturvedi, S S; Jha, S K

    2012-07-01

    A radiation dose assessment exercise was carried out for the edible biota Solanum nigrum, Carica papaya, Raphnus sativum and Phaseolus domesticus due to naturally available radionuclides (40)K, (238)U and (232)Th in the Domiasiat area in Meghalaya, India. The concentration of radionuclides in biota and corresponding soil was measured by the NaI(Tl) detector having a minimum detection limit (efficiency, 32.4%) and machine counting time of 3000 s. The obtained transfer factor for (40)K was 0.3061, 0.7163, 0.1988 and 0.1279, for (232)Th 0.0003, 2.22E-05, 2.71E-05 and 3.45E-05 and for (238)U 1.46E-05, 9.73E-05, 1.46E-05 and 3.11E-05 (ratio) in each biota, respectively. The detailed physiological and morphological study of the biota was carried out. The point source dose distribution (source↔target) hypothesis was applied for the radiation absorbed fraction. The generated data were modelled using FASSET and obtained un-weighted total dose was 1.78E-04, 6.84E-03, 8.46E-03 and 1.73E-04 μGy h(-1), respectively, finally compared with the IAEA and UNSCEAR data set for screening level dose risk assessment. PMID:22155750

  3. Soil biota enhance agricultural sustainability by improving crop yield, nutrient uptake and reducing nitrogen leaching losses

    NARCIS (Netherlands)

    Bender, S.F.; van der Heijden, M.G.A.

    2015-01-01

    Efficient resource use is a key factor for sustainable production and a necessity for meeting future global food demands. However, the factors that control resource use efficiency in agro-ecosystems are only partly understood. We investigated the influence of soil biota on nutrient leaching, nutrien

  4. Pathogenic agents in freshwater resources

    Science.gov (United States)

    Geldreich, Edwin E.

    1996-02-01

    Numerous pathogenic agents have been found in freshwaters used as sources for water supplies, recreational bathing and irrigation. These agents include bacterial pathogens, enteric viruses, several protozoans and parasitic worms more common to tropical waters. Although infected humans are a major source of pathogens, farm animals (cattle, sheep, pigs), animal pets (dogs, cats) and wildlife serve as significant reservoirs and should not be ignored. The range of infected individuals within a given warm-blooded animal group (humans included) may range from 1 to 25%. Survival times for pathogens in the water environment may range from a few days to as much as a year (Ascaris, Taenia eggs), with infective dose levels varying from one viable cell for several primary pathogenic agents to many thousands of cells for a given opportunistic pathogen.As pathogen detection in water is complex and not readily incorporated into routine monitoring, a surrogate is necessary. In general, indicators of faecal contamination provide a positive correlation with intestinal pathogen occurrences only when appropriate sample volumes are examined by sensitive methodology.Pathways by which pathogens reach susceptible water users include ingestion of contaminated water, body contact with polluted recreational waters and consumption of salad crops irrigated by polluted freshwaters. Major contributors to the spread of various water-borne pathogens are sewage, polluted surface waters and stormwater runoff. All of these contributions are intensified during periods of major floods. Several water-borne case histories are cited as examples of breakdowns in public health protection related to water supply, recreational waters and the consumption of contaminated salad crops. In the long term, water resource management must focus on pollution prevention from point sources of waste discharges and the spread of pathogens in watershed stormwater runoff.

  5. Trait-based modelling of bioaccumulation by freshwater benthic invertebrates.

    Science.gov (United States)

    Sidney, Livia Alvarenga; Diepens, Noël J; Guo, Xiaoying; Koelmans, Albert A

    2016-07-01

    Understanding the role of species traits in chemical exposure is crucial for bioaccumulation and toxicity assessment of chemicals. We measured and modelled bioaccumulation of polychlorinated biphenyls (PCBs) in Chironomus riparius, Hyalella azteca, Lumbriculus variegatus and Sphaerium corneum. We used a battery test procedure with multiple enclosures in one aquarium, which maximized uniformity of exposure for the different species, such that the remaining variability was due mostly to species traits. The relative importance of uptake from either pore water or sediment ingestion was manipulated by using 28 d aged standard OECD sediment with low (1%) and medium (5%) OM content and 13 months aged sediment with medium OM (5%) content. Survival was ≥76% and wet weight increased for all species. Reproduction of H. azteca and weight gain of H. azteca and S. corneum were significantly higher in the medium OM aged sediments than in other sediments, perhaps due to a more developed microbial community (i.e., increase in food resources). Biota-sediment accumulation factors (BSAF) ranged from 3 to 114, depending on species and PCB congener, with C. riparius (3-10)freshwater taxonomic groups were compared with their marine counterparts and showed overlapping values. The dynamic bioaccumulation model with species-specific bioaccumulation parameters fitted well to the experimental data and showed that bioaccumulation parameters were depended on species traits. Enclosure-based battery tests and mechanistic BSAF models are expected to improve the quality of the exposure assessment in whole sediment toxicity tests. PMID:27126443

  6. Metal toxicity to freshwater organisms as a function of pH: A meta-analysis.

    Science.gov (United States)

    Wang, Zhen; Meador, James P; Leung, Kenneth M Y

    2016-02-01

    Acidification caused by climate change and seasonal fluctuation can have profound implications for chemical toxicity to freshwater organisms. The present study aims to address this challenging issue through a comprehensive meta-analysis by comparing acute median lethal or effect concentration data (LC50 or EC50) for 10 metals and metalloids for various freshwater species obtained at different pH values. Our results revealed that element toxicity generally follows three different models, including Model-I: decreasing toxicity with increasing pH, Model-II: increasing toxicity with increasing pH, and Model-III: minimal toxicity at intermediate (optimal) pH (pH(opt)) with increasing toxicity as pH increases or decreases from pH(opt). We further examined these observations by constructing pH-dependent species sensitivity distributions (SSDs). The results indicated that the 10(th) percentile hazardous concentrations (HC10s) for copper, lead, selenium and silver generally exhibited a positive linear relationship with pH, following the Model-I. The ability to accurately predict toxicity of elements to biota in natural waters as a function of pH may be limited, however, the pH-dependent SSD approach presented in this study facilitates and helps characterize the role of pH in water quality guidelines and ecological risk assessment.

  7. The freshwater reservoir effect in radiocarbon dating

    DEFF Research Database (Denmark)

    Philippsen, Bente

    case studies will show the degree of variability of the freshwater reservoir effect over short and long timescales. Radiocarbon dating of recent water samples, aquatic plants and animals, shows that age differences of up to 2000 years can occur within one river. In the Limfjord, freshwater influence...... caused reservoir ages to vary between 250 and 700 years during the period 5400 BC - AD 700. Finally, I will discuss the implications of the freshwater reservoir effect for radiocarbon dating of Mesolithic pottery from inland sites of the Ertebølle culture in Northern Germany....

  8. The freshwater crab, Trichodactylus fluviatilis (Latreille, 1828 (Crustacea, Decapoda, Trichodactylidae, as perceived by the inhabitants of the county of Pedra Branca, Bahia, Brazil

    Directory of Open Access Journals (Sweden)

    Eraldo Medeiros Costa Neto

    2007-03-01

    Full Text Available Freshwater crabs are key elements of the aquatic biota of streams, rivers, lakes, and dams because of their ecological and economic importance. Considering that Trichodactylus fluviatilis (Latreille, 1828 is an important source of food for the human settlements that inhabit the places of its occurrence, this article records, for the first time, an ethnocarcinological study carried out with the inhabitants of Pedra Branca county, Bahia State. Data were obtained from February to June 2005 by means of open-ended interviews using the usual techniques of ethnographical survey. Sixteen women and eleven men were interviewed. Their ages ranged from 25 to 86 years old. The results showed that the ethnocarcinological knowledge about T. fluviatilis is relatively consistent with academic knowledge. Ethnozoological studies that stress the cultural significance of freshwater crustaceans are very important, since they would represent a great contribution to the debate on biodiversity conservation in the environments these animals inhabit.

  9. Potential ecological risk of heavy metal contamination in sediments and macrobenthos in coastal wetlands induced by freshwater releases: A case study in the Yellow River Delta, China.

    Science.gov (United States)

    Li, Ming; Yang, Wei; Sun, Tao; Jin, Yuwan

    2016-02-15

    We investigated the nine heavy metal contents in the sediments and macrobenthos of the Yellow River Delta Wetlands using three experimental areas that received freshwater releases and one reference area that did not. Heavy metal contents, the single-factor contamination index (SFCI), the metal contamination index (MCI), and the biota-sediment accumulation factor (BSAF) were used to evaluate the potential ecological risk and bioaccumulation. We found that As exceeded the national standard value by more than 50%, and that the ranges of SFCI for each metal were generally larger in autumn than in spring. MCI showed no clear pattern, but the BSAF results suggest that Cd bioaccumulates from sediments to macrobenthos. Pollution-resistant species such as Corophium sinense, Chironomus sp., and Einfeldia sp. became dominant in the areas receiving freshwater releases, and provide direct evidence of ecological risk in the wetlands. Our results provide preliminary information to guide managers for ecological risk assessments. PMID:26719069

  10. 40 CFR 35.1605-3 - Publicly owned freshwater lake.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Publicly owned freshwater lake. 35.1605... Owned Freshwater Lakes § 35.1605-3 Publicly owned freshwater lake. A freshwater lake that offers public access to the lake through publicly owned contiguous land so that any person has the same opportunity...

  11. Surface-water-quality assessment of the Yakima River basin in Washington: major-and minor-element data for sediment, water, and aquatic biota, 1987-91

    Science.gov (United States)

    Fuhrer, Gregory J.; Fluter, Shelley L.; McKenzie, Stuart W.; Rinella, Joseph F.; Crawford, J. Kent; Cain, Daniel J.; Hornberger, Michelle I.; Bridges, Jennifer L.; Skach, Kenneth A.

    1994-01-01

    Major- and minor-element concentrations are presented for streambed and suspended sediment, filtered- and unfiltered-water, and aquatic-biota samples collected during 1987-91 from the Yakima River Basin in south-central Washington. The samples were collected as part of the U.S. Geological Survey's National Water-quality Assessment (NAWQA) program which is designed to provide results that are useful in understanding and managing the Nation's water resources. This report includes the sampling approach, field collection and processing techniques, and methods of chemical analysis, as well as a compilation of chemical data, statistical summaries, and quality- control data. These data may be used by scientists and resource managers to describe (1) spatial distribution of selected major and minor elements in sediment, water, and aquatic biota of the Yakima River Basin; (2) temporal variation for element concentrations in filtered water and in suspended sediment at selected sites; (3) suita- bility of surface water for preservation of aquatic life and protection of human health; and (4) major natural and anthropogenic sources of major and minor elements in the Yakima River Basin that affect observed water-quality conditions.

  12. Net effects of multiple stressors in freshwater ecosystems: a meta-analysis.

    Science.gov (United States)

    Jackson, Michelle C; Loewen, Charlie J G; Vinebrooke, Rolf D; Chimimba, Christian T

    2016-01-01

    The accelerating rate of global change has focused attention on the cumulative impacts of novel and extreme environmental changes (i.e. stressors), especially in marine ecosystems. As integrators of local catchment and regional processes, freshwater ecosystems are also ranked highly sensitive to the net effects of multiple stressors, yet there has not been a large-scale quantitative synthesis. We analysed data from 88 papers including 286 responses of freshwater ecosystems to paired stressors and discovered that overall, their cumulative mean effect size was less than the sum of their single effects (i.e. an antagonistic interaction). Net effects of dual stressors on diversity and functional performance response metrics were additive and antagonistic, respectively. Across individual studies, a simple vote-counting method revealed that the net effects of stressor pairs were frequently more antagonistic (41%) than synergistic (28%), additive (16%) or reversed (15%). Here, we define a reversal as occurring when the net impact of two stressors is in the opposite direction (negative or positive) from that of the sum of their single effects. While warming paired with nutrification resulted in additive net effects, the overall mean net effect of warming combined with a second stressor was antagonistic. Most importantly, the mean net effects across all stressor pairs and response metrics were consistently antagonistic or additive, contrasting the greater prevalence of reported synergies in marine systems. Here, a possible explanation for more antagonistic responses by freshwater biota to stressors is that the inherent greater environmental variability of smaller aquatic ecosystems fosters greater potential for acclimation and co-adaptation to multiple stressors.

  13. An assessment of mercury in waters, sediments and biota of Vermont and New Hampshire lakes [Draft

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The present report summarizes findings of a three-year field study of mercury in freshwater lakes of Vermont and New Hampshire. The study was undertaken jointly by...

  14. Exotic freshwater planarians currently known from Japan

    NARCIS (Netherlands)

    R. Sluys; M. Kawakatsu; K. Yamamoto

    2010-01-01

    Biogeographical and taxonomic information on the four non-indigenous freshwater planarians of Japan is reviewed, viz. Dugesia austroasiatica Kawakatsu, 1985, Girardia tigrina (Girard, 1850), G. dorotocephala (Woodworth, 1897), and Rhodax evelinae? Marcus, 1947. The occurrence of Girardia dorotocepha

  15. Adaptive diversity: hormones and metabolism in freshwaters.

    Science.gov (United States)

    Laudet, Vincent

    2010-12-01

    Genes underlying the evolution of morphological traits have recently been identified in a number of model species. In the stickleback, the metabolic adaptations to a freshwater habitat have now been linked to a well-known hormonal system. PMID:21145015

  16. Survey for contaminants in sediments and fish at selected sites on the Illinois River and tributaries

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — A basin-wide survey of contaminants in sediments and biota at several locations on the Illinois River and selected tributaries was conducted during the 1989 field...

  17. Environmental Contaminants Monitoring in Selected Wetlands of Wyoming: Biologically Active Elements Study

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Sediment, water and biota were collected from selected wetlands in Wyoming for the Biologically Active Elements (BAE) Study in 1988, 1989 and 1990 to identify...

  18. Monitoring of suspended sediments, sediment conditions and aquatic biota during the functional check of bottom outlets

    Science.gov (United States)

    Haun, Stefan; Seitz, Lydia; Stockinger, Wolfram; Riedl, Martin; Schletterer, Martin

    2016-04-01

    Reservoirs are used to store water for multiple purposes and are therefore of great importance for our society. Regularly inspections of the dam structure and the bottom outlets are necessary to ensure a safe operation of these structures. The release of water from the reservoirs for this procedure often results in high suspended sediment concentrations downstream by the remobilization of deposited sediments, which may result further in negative effects on the downstream located habitats. Due to a careful elaborated monitoring concept, e.g. regarding the opening procedure of the bottom outlets, it is possible to change the management strategy and to avoid or to minimize ecological impacts. Within this study a monitoring concept is developed and implemented to observe occurring suspended sediment concentrations during the opening of the bottom outlets of a small reservoir in the alpine region. The measurement concept includes suspended sediment concentration and discharge measurements at the two upstream located tributaries as well as suspended sediment concentration measurements downstream. Two stations are selected downstream with a distance of 750 m and 2,000 m from the dam. To ensure a complete series of concentrations over time bottom samples, Imhoff-cones as well as turbidity meters are implemented. Whereas the turbidity meters ensure a permanent observation of the conditions (will be calibrated with laboratory results from the bottle samples), the Imhoff-cones make it possible to intervene right away into the process of releasing water. A second focus lies on the downstream located river bed, which is monitored before and after the opening of the bottom outlets in order to assess morphodynamical changes such as river bed clogging occurs. Therefore sediment samples with the so called freeze-panel technique are collected before and after the opening of the bottom outlets to quantify possible changes of the bed material. The results show that downstream habitats

  19. Interactions between soil biota and the effects on geomorphological features

    Science.gov (United States)

    Zaitlin, Beryl; Hayashi, Masaki

    2012-07-01

    The interaction of animals with abiotic features of their environment has long been known to cause alterations to geomorphic features, and these interactions may cause feedback loops that further alter geomorphic features and animal communities. This paper samples the literature on selected burrowing animals in western North America, and discusses the interactions of animals with abiotic features of the environment and with each other, and the resulting impacts on geomorphic features and each other. As expected, burrowing characteristics of animals influence geomorphological processes. For example, pocket gophers and certain ground squirrels that burrow horizontal tunnels on sloping grounds seem to have significant impacts on horizontal movement of soils, whereas prairie dogs and harvester ants have more impact on vertical movement of soils. Burrowing animals, in general, increase the patchiness of the environment, which creates localized patch habitat for other plants and animals, thereby increasing biodiversity at the landscape scale. Burrowing animals influence and are influenced by microbes: sylvatic plague wiped out large populations of prairie dogs, earthworms cause major changes in soil microflora, pocket gophers and harvester ants cause changes in mycorrhizal communities, which in turn impact plant communities.

  20. Freshwater Commercial Bycatch: an Understated Conservation Problem

    Energy Technology Data Exchange (ETDEWEB)

    Raby, Graham D.; Colotelo, Alison HA; Blouin-Demers, Gabriel; Cooke, Steven J.

    2011-04-01

    Commercial fisheries bycatch in marine systems has been regarded as a global conservation concern by environmental groups, scientists, government, and the public for decades. Fortunately, some headway has been made to mitigate the negative impacts of bycatch in marine environments. In a survey of the literature, we found that despite freshwater commercial fisheries yields comprising 11% of the global commercial catch, bycatch research focusing on freshwater commercial fisheries represented only {approx}3% of the total bycatch literature. This paucity of research is particularly alarming given that freshwater animals and habitats are some of the world's most imperiled. The limited inland bycatch literature that does exist includes examples of population declines attributed to commercial bycatch (e.g., freshwater dolphins in the Yangtze River in China) and illustrates that in some systems bycatch can be substantial (e.g., lake trout bycatch in the Laurentian Great Lakes). Encouraging results from the marine realm can serve as models for bycatch research in freshwater, and lead to measurable gains in conservation of freshwater ecosystems. We summarize existing work on inland bycatch in an effort to draw attention to this understated and understudied conservation problem.

  1. COMMUNITY DEVELOPMENT IN FRESHWATER MICROCOSMS

    Energy Technology Data Exchange (ETDEWEB)

    Rees, John T.

    1978-01-01

    Two cylindrical freshwater microcosms with a volume of 700 {ell} were maintained under controlled laboratory conditions for 190 days. The two microcosms were identical with regard to initial chemical composition and biological inocula, with the exceptions that in one microcosm (designated Tank 2) mosquitofish (Gambusia) and herbivorous catfish (Placostomas) were added. Three distinct communities developed in the tanks: (1) a phytoplankton-zooplankton assemblage and (2) two periphyton-zoobenthos communities associated with the sides and bottom of the tank, respectively. Community development and successional patterns were similar in both tanks. Major differences between the tanks involved timing of succession of the zooplankton and zoobenthos, attributable to predation by fish, principally Gambusia. A major drawback for these microcosms as use for experimental analogs such as lakes was a luxuriant periphyton growth which eventually overwhelmed the biomass of the system. The tanks displayed a degree of successional replicability, a large number of species, and a diversity of community development. Microcosms of this size could find use as experimental systems for higher level trophic manipulation and observation of life cycles not amenable to field studies.

  2. Open minded and open access : introducing NeoBiota,a new peer-reviewed journal of biological invasions

    OpenAIRE

    Ingolf Kühn; Ingo Kowarik; Johannes Kollmann; Uwe Starfinger; Sven Bacher; Tim Blackburn; Ramiro Bustamante; Laura Celesti-Grapow; Milan Chytrý; Robert Colautti; Franz Essl; Llewellyn Foxcroft; Stephan Gollasch; Emili García-Berthou; José Hierro

    2011-01-01

    The Editorial presents the focus, scope, policies, and the inaugural issue of NeoBiota, a new open access peer-reviewed journal of biological invasions. The new journal NeoBiota is a continuation of the former NEOBIOTA publication series. The journal will deal with all aspects of invasion biology and impose no restrictions on manuscript size neither on use of color. NeoBiota implies an XML-based editorial workflow and several cutting-edge innovations in publishing and dissemination, such as s...

  3. Modeling ecosystem processes with variable freshwater inflow to the Caloosahatchee River Estuary, southwest Florida. I. Model development

    Science.gov (United States)

    Buzzelli, Christopher; Doering, Peter H.; Wan, Yongshan; Sun, Detong; Fugate, David

    2014-12-01

    Variations in freshwater inflow have ecological consequences for estuaries ranging among eutrophication, flushing and transport, and high and low salinity impacts on biota. Predicting the potential effects of the magnitude and composition of inflow on estuaries over a range of spatial and temporal scales requires reliable mathematical models. The goal of this study was to develop and test a model of ecosystem processes with variable freshwater inflow to the sub-tropical Caloosahatchee River Estuary (CRE) in southwest Florida from 2002 to 2009. The modeling framework combined empirically derived inputs of freshwater and materials from the watershed, daily predictions of salinity, a box model for physical transport, and simulation models of biogeochemical and seagrass dynamics. The CRE was split into 3 segments to estimate advective and dispersive transport of water column constituents. Each segment contained a sub-model to simulate changes in the concentrations of organic nitrogen and phosphorus (ON and OP), ammonium (NH4+), nitrate-nitrite (NOx-), ortho-phosphate (PO4-3), phytoplankton chlorophyll a (CHL), and sediment microalgae (SM). The seaward segment also had sub-models for seagrasses (Halodule wrightii and Thalassia testudinum). The model provided realistic predictions of ON in the upper estuary during wet conditions since organic nitrogen is associated with freshwater inflow and low salinity. Although simulated CHL concentrations were variable, the model proved to be a reliable predictor in time and space. While predicted NOx- concentrations were proportional to freshwater inflow, NH4+ was less predictable due to the complexity of internal cycling during times of reduced freshwater inflow. Overall, the model provided a representation of seagrass biomass changes despite the absence of epiphytes, nutrient effects, or sophisticated translocation in the formulation. The model is being used to investigate the relative importance of colored dissolved organic

  4. SUPPRESSION ABILITY OF CRUDE EXTRACT DERIVED FROM MARINE BIOTA AGAINST FUSARIUM OXYSPORUM F.SP. VANILLAE

    Directory of Open Access Journals (Sweden)

    I Ketut Suada

    2010-06-01

    Full Text Available The objective of this research was to investigate suppression ability of marine biota extracts against Fusarium oxysporum f.sp. vanillae of vanilla stem rot. Samples were collected at intertidal zones and in the depth of 1-7 m from seven beaches in Bali. Screening of active compounds of biota extracts were conducted using inhibition zone of well diffusion method on Potato Dextrose Agar (PDA. The extract was tested in-vitro in PDA medium using completely randomized design with three replicates. The methanolic extract of Aglaophenia sp. was able to suppress the growth of F. oxysporum f.sp. vanillae effectively, with minimum inhibition concentration (MIC of 0.05 %. The extract inhibited colony growth diameter and total mycelial dry weight.

  5. Methods for calculating dose conversion coefficients for terrestrial and aquatic biota

    International Nuclear Information System (INIS)

    Plants and animals may be exposed to ionizing radiation from radionuclides in the environment. This paper describes the underlying data and assumptions to assess doses to biota due to internal and external exposure for a wide range of masses and shapes living in various habitats. A dosimetric module is implemented which is a user-friendly and flexible possibility to assess dose conversion coefficients for aquatic and terrestrial biota. The dose conversion coefficients have been derived for internal and various external exposure scenarios. The dosimetric model is linked to radionuclide decay and emission database, compatible with the ICRP Publication 38, thus providing a capability to compute dose conversion coefficients for any nuclide from the database and its daughter nuclides. The dosimetric module has been integrated into the ERICA Tool, but it can also be used as a stand-alone version

  6. Modelling of Biota Dose Effects. Report of Working Group 6 Biota Dose Effects Modelling of EMRAS II Topical Heading Reference Approaches for Biota Dose Assessment. Environmental Modelling for RAdiation Safety (EMRAS II) Programme

    International Nuclear Information System (INIS)

    Environmental assessment models are used for evaluating the radiological impact of actual and potential releases of radionuclides to the environment. They are essential tools for use in the regulatory control of routine discharges to the environment and in planning the measures to be taken in the event of accidental releases. They are also used for predicting the impact of releases which may occur far into the future, for example, from underground radioactive waste repositories. It is important to verify, to the extent possible, the reliability of the predictions of such models by a comparison with measured values in the environment or with the predictions of other models. The IAEA has been organizing programmes on international model testing since the 1980s. These programmes have contributed to a general improvement in models, in the transfer of data and in the capabilities of modellers in Member States. IAEA publications on this subject over the past three decades demonstrate the comprehensive nature of the programmes and record the associated advances which have been made. From 2009 to 2011, the IAEA organized a project entitled Environmental Modelling for RAdiation Safety (EMRAS II), which concentrated on the improvement of environmental transfer models and the development of reference approaches to estimate the radiological impacts on humans, as well as on flora and fauna, arising from radionuclides in the environment. Different aspects were addressed by nine working groups covering three themes: reference approaches for human dose assessment, reference approaches for biota dose assessment and approaches for addressing emergency situations. This publication describes the work of the Biota Effects Modelling Working Group

  7. A Modelling Framework to Assess the Effect of Pressures on River Abiotic Habitat Conditions and Biota.

    Directory of Open Access Journals (Sweden)

    Jochem Kail

    Full Text Available River biota are affected by global reach-scale pressures, but most approaches for predicting biota of rivers focus on river reach or segment scale processes and habitats. Moreover, these approaches do not consider long-term morphological changes that affect habitat conditions. In this study, a modelling framework was further developed and tested to assess the effect of pressures at different spatial scales on reach-scale habitat conditions and biota. Ecohydrological and 1D hydrodynamic models were used to predict discharge and water quality at the catchment scale and the resulting water level at the downstream end of a study reach. Long-term reach morphology was modelled using empirical regime equations, meander migration and 2D morphodynamic models. The respective flow and substrate conditions in the study reach were predicted using a 2D hydrodynamic model, and the suitability of these habitats was assessed with novel habitat models. In addition, dispersal models for fish and macroinvertebrates were developed to assess the re-colonization potential and to finally compare habitat suitability and the availability/ability of species to colonize these habitats. Applicability was tested and model performance was assessed by comparing observed and predicted conditions in the lowland Treene River in northern Germany. Technically, it was possible to link the different models, but future applications would benefit from the development of open source software for all modelling steps to enable fully automated model runs. Future research needs concern the physical modelling of long-term morphodynamics, feedback of biota (e.g., macrophytes on abiotic habitat conditions, species interactions, and empirical data on the hydraulic habitat suitability and dispersal abilities of macroinvertebrates. The modelling framework is flexible and allows for including additional models and investigating different research and management questions, e.g., in climate impact

  8. Sustainable management and conservation of biota in agricultural soils of the Republic of Moldova

    OpenAIRE

    Senicovscaia, Irina

    2012-01-01

    In present research the ways and methods of the sustainable management and conservation of the soil biota in the modern agricultural ecosystems of the Republic of Moldova are considered. The database of invertebrates, microorganisms and enzymatic activities of different zonal soils in the long-term field experiments has been developed and constantly is updated with a view to the operative evaluation of the degradation processes and ecological effectiveness of the land management. The current ...

  9. Biota of a Pennsylvanian muddy coast: habitat within the Mazonian delta complex, northeast Illinois

    Energy Technology Data Exchange (ETDEWEB)

    Baird, G.C.

    1985-03-01

    The Mazon Creek biota (Westphalian D) is composed of plants and animals from terrestrial fresh water and marginal marine habitats. Fossil animals, including jellyfish, worms, crustaceans, holothurians, insects, chordates, and problematica occur in sideritic concretions on spoilpiles of more than 100 abandoned coal mines in a five county region (Mazon Creek area) of northeast Illinois. These fossils record rapid burial and early diagenesis in a muddy, delta-influenced coastal setting submerged during marine transgression.

  10. Arthropod visual predators in the early pelagic ecosystem: evidence from the Burgess Shale and Chengjiang biotas

    OpenAIRE

    Vannier, J; García-Bellido, D.C.; Hu, S.-X.; Chen, A.-L.

    2009-01-01

    Exceptional fossil specimens with preserved soft parts from the Maotianshan Shale (ca 520 Myr ago) and the Burgess Shale (505 Myr ago) biotas indicate that the worldwide distributed bivalved arthropod Isoxys was probably a non-benthic visual predator. New lines of evidence come from the functional morphology of its powerful prehensile frontal appendages that, combined with large spherical eyes, are thought to have played a key role in the recognition and capture of swimming or epibenthic prey...

  11. An adaptation of human food chain models to predicting internal exposure of biota: the Faster model

    International Nuclear Information System (INIS)

    There is an acknowledged lack of available data to derive parameters describing the transfer of many radionuclides from soil to wild species. Furthermore, many approaches to estimating the internal exposure of biota assume equilibrium transfer from soil to biota. However, as environmental impact assessments may need to be conducted for many scenarios (e.g. chronic or acute releases to air and ground waters) assumptions of equilibrium soil to biota transfer many be neither sufficient nor conservative. Much effort has previously been devoted to derive semi-mechanistic models to enable the transfer of radionuclides through human food chains to be predicted dynamically. A logical first step to addressing the data gaps in our ability to predict internal activity concentrations of biota is to consider adapting these models for wild species. Here we describe the development of a semi-mechanistic model to estimate activity concentrations in wild mammals by adaptation of existing human food chain models. Interception, weathering, plant uptake and soil migration parameters are derived from previously published models or collations such as IAEA Technical Report Series No. 364. Allometric relationships dependent on body mass are used to estimate wild animal parameters including, for most radionuclides, biological half-life. Comparison of predictions with observed data allows limited comment on the validity of model predictions. For instance, predicted Cs values are within observed ranges, and an increase in Cs activity concentrations from prey-carnivore as observed by many authors is predicted. Predicted values for 90Sr, 226Ra and U also appear reasonable whilst those for the actinide elements are low compared with the limited available data. To date a simple source-grass-herbivore-carnivore food chain has been considered; the potential for further development of the model is discussed. (author)

  12. Historical records of radioactive contamination in biota at the 200 Areas of the Hanford Site

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, A.R.; Markes, B.M.; Schmidt, J.W.; Shah, A.N.; Weiss, S.G.; Wilson, K.J.

    1994-06-01

    This document summarizes and reports a literature search of 85 environmental monitoring records of wildlife and vegetation (biota) at the 200 East Area and the 200 West Area of the Hanford Site since 1965. These records were published annually and provided the majority of the data in this report. Additional sources of data have included records of specific facilities, such as site characterization documents and preoperational environmental surveys. These documents have been released for public use. Records before 1965 were still being researched and therefore not included in this document. The intent of compiling these data into a single source was to identify past and current concentrations of radionuclides in biota at specific facilities and waste sites within each operable unit that may be used to help guide cleanup activities in the 200 Areas to be completed under the Comprehensive Environmental Response and Liability Act (CERCLA). The 200 East Area and 200 West Area were the locations of the Hanford Site separation and process facilities and waste management units. For the purposes of this document, a sample was of interest if a Geiger-Mueller counter equipped with a pancake probe-indicated beta/gamma emitting radioactivity above 200 counts per minute (cpm), or if laboratory radioanalyses indicated a radionuclide concentration equaled or exceeded 10 picocuries per gram (pCi/g). About 4,500 individual cases of monitoring for radionuclide uptake or transport in biota in the 200 Areas environs were included in the documents reviewed. About 1,900 (i.e., 42%) of these biota had radionuclide concentrations in excess of 10 pCi/g. These radionuclide transport or uptake cases were distributed among 45 species of wildlife (primarily small mammals and feces) and 30 species of vegetation. The wildlife species most commonly associated with radioactive contamination were the house mouse and the deer mouse and of vegetation species, the Russian thistle.

  13. Non-human biota dose assessment. Sensitivity analysis and knowledge quality assessment

    International Nuclear Information System (INIS)

    This report provides a summary of a programme of work, commissioned within the BIOPROTA collaborative forum, to assess the quantitative and qualitative elements of uncertainty associated with biota dose assessment of potential impacts of long-term releases from geological disposal facilities (GDF). Quantitative and qualitative aspects of uncertainty were determined through sensitivity and knowledge quality assessments, respectively. Both assessments focused on default assessment parameters within the ERICA assessment approach. The sensitivity analysis was conducted within the EIKOS sensitivity analysis software tool and was run in both generic and test case modes. The knowledge quality assessment involved development of a questionnaire around the ERICA assessment approach, which was distributed to a range of experts in the fields of non-human biota dose assessment and radioactive waste disposal assessments. Combined, these assessments enabled critical model features and parameters that are both sensitive (i.e. have a large influence on model output) and of low knowledge quality to be identified for each of the three test cases. The output of this project is intended to provide information on those parameters that may need to be considered in more detail for prospective site-specific biota dose assessments for GDFs. Such information should help users to enhance the quality of their assessments and build greater confidence in the results. (orig.)

  14. On the horizon of Protopteryx and the early vertebrate fossil assemblages of the Jehol Biota

    Institute of Scientific and Technical Information of China (English)

    JIN Fan; ZHANG FuCheng; LI ZhiHeng; ZHANG JiangYong; LI Chun; ZHOU ZhongHe

    2008-01-01

    Protopteryx, a monotypic fossil bird discovered from the Sichakou basin in Fengning, Hebei, is the most primitive enantiornithine currently known. The bird-bearing strata do not contain the index fossils of the Yixian Formation in western Liaoning; the fish and bird fossils have more primitive features than the related forms found in the Yixian Formation, and the conchostracans are those usually distributed in the Dabeigou and Dadianzi formations in northern Hebei. Besides, the Protopteryx-bearing strata underlie the deposits bearing the index fossils of the Yixian Formation in the neighboring basin. Thus, it could be confirmed that the horizon of Protopteryx should be lower than the Yixian Formation, and is approximately equivalent to the Dadianzi Formation in northern Hebei. This is the lowest horizon of the known fossil birds in China and Mesozoic enantiornithine birds in the world. Accompanying Protop-teryx, there are other birds, acipenseriform fishes, salamanders, and mammals, which compose the Peipiaosteus fengningensis-Protopteryx fengningensis assemblage. This new assemblage traces the vertebrate evolution history of the Jehol Biota back to 130.7 Ma before. It is suggested that the de-marcation of the Jehol Biota should be based on the large-scale tectonic-sedimentary cycles, and Peipiaosteus, instead of Lycoptera, could be taken as the vertebrate representative of the Jehol Biota.

  15. Radioactivity in produced water from oil and gas installations - doses to biota and humans

    International Nuclear Information System (INIS)

    Substantial amounts of produced water containing elevated levels of 226Ra and 228Ra are discharged into the sea as a result of oil and gas production on the Norwegian continental shelf. The average concentration in the discharges is 3.3 and 2.8 Bq/L of 226Ra and 228Ra, respectively. The main objective of the project described in the paper is to establish radiological safe discharge limits for radium, lead and polonium in produced water produced by oil and gas installations on the Norwegian continental shelf. One of the objectives of the study is to provide information to enable risk assessment based on doses from ionizing radiation to marine biota and man. Reference organisms for the North Sea area have been chosen for calculation of absorbed dose to biota. The dose calculations rely on specific knowledge of activity concentration in the reference organism, activity concentration in seawater and sediments, dose conversion factors and time spent at different locations relative to the point of discharge. Based on the calculated doses to marine biota, 'potential no effect concentrations' are recommended. (author)

  16. The Hunsrück biota: A unique window into the ecology of Lower Devonian arthropods.

    Science.gov (United States)

    Rust, Jes; Bergmann, Alexandra; Bartels, Christoph; Schoenemann, Brigitte; Sedlmeier, Stephanie; Kühl, Gabriele

    2016-03-01

    The approximately 400-million-year old Hunsrück biota provides a unique window into Devonian marine life. Fossil evidence suggests that this biota was dominated by echinoderms and various classes of arthropods, including Trilobita, stem lineage representatives of Euarthropoda, Chelicerata and Eucrustacea, as well as several crown group Chelicerata and Eucrustacea. The Hunsrück biota's exceptional preservation allows detailed reconstructions and description of key-aspects of its fauna's functional morphologies thereby revealing modes of locomotion, sensory perception, and feeding strategies. Morphological and stratigraphic data are used for a critical interpretation of the likely habitats, mode of life and nutritional characteristics of this diverse fauna. Potential predators include pycnogonids and other chelicerates, as well as the now extinct stem arthropods Schinderhannes bartelsi, Cambronatus brasseli and Wingertshellicus backesi. Mainly the deposit feeding Trilobita, Marrellomorpha and Megacheira, such as Bundenbachiellus giganteus, represents scavengers. Possibly, opportunistic scavenging was also performed by the afore-mentioned predators. Most of the studied arthropods appear to have been adapted to living in relatively well-illuminated conditions within the photic zone. Fossil evidence for associations amongst arthropods and other classes of metazoans is reported. These associations provide evidence of likely community structures.

  17. Trophodynamics of hexabromocyclododecanes and several other non-PBDE brominated flame retardants in a freshwater food web.

    Science.gov (United States)

    Wu, Jiang-Ping; Guan, Yun-Tao; Zhang, Ying; Luo, Xiao-Jun; Zhi, Hui; Chen, She-Jun; Mai, Bi-Xian

    2010-07-15

    Several currently used non-polybrominated diphenyl ether (PBDE) brominated flame retardants (BFRs), including hexabromocyclododecanes (HBCDs), 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), decabromodiphenyl ethane (DBDPE), hexabromobenzene (HBB), pentabromoethylbenzene (PBEB), and pentabromotoluene (PBT), are examined in the components of a freshwater food web from an electronic waste recycling site, South China. All these BFRs are detectable in the food web, with average concentrations of 13.9-868, 1.71-518, Food web magnification is observed for (+)-alpha-, (-)-alpha-, (+/-)-alpha-, and total HBCDs, and HBB, with trophic magnification factors (TMFs) of 2.22, 2.18, 2.19, 1.82, and 1.46, respectively; whereas there is trophic dilution of BTBPE and PBT through the food web. The TMFs for (+)-alpha-, (-)-alpha-, and (+/-)-alpha-HBCDs are comparable to those of PBDEs detected previously in the same food web. Biota samples show a shift from gamma- toward alpha-HBCD compared with the suspended particles, sediment, and HBCD technical mixtures, with a significant increase of alpha-HBCD on ascending trophic levels. Except for alpha-HBCD in suspended particles and sediment, all the HBCD enantiomers detected are nonracemic in the environmental matrix. In biota, nonracemic residues of alpha-HBCD were observed in mud carp and crucian carp; beta-HBCD in prawn, mud carp, and crucian carp; and gamma-HBCD in water snake, with preferences for (+)-alpha-, (-)-beta-, and (+)-gamma-HBCDs. PMID:20575536

  18. Deriving freshwater quality criteria for iron, lead, nickel, and zinc for protection of aquatic life in Malaysia.

    Science.gov (United States)

    Shuhaimi-Othman, M; Nadzifah, Y; Nur-Amalina, R; Umirah, N S

    2012-01-01

    Freshwater quality criteria for iron (Fe), lead (Pb), nickel (Ni), and zinc (Zn) were developed with particular reference to aquatic biota in Malaysia, and based on USEPA's guidelines. Acute toxicity tests were performed on eight different freshwater domestic species in Malaysia which were Macrobrachium lanchesteri (prawn), two fish: Poecilia reticulata and Rasbora sumatrana, Melanoides tuberculata (snail), Stenocypris major (ostracod), Chironomus javanus (midge larvae), Nais elinguis (annelid), and Duttaphrynus melanostictus (tadpole) to determine 96 h LC(50) values for Fe, Pb, Ni, and Zn. The final acute value (FAV) for Fe, Pb, Ni, and Zn were 74.5, 17.0, 165, and 304.9 μg L(-1), respectively. Using an estimated acute-to-chronic ratio (ACR) of 8.3, the value for final chronic value (FCV) was derived. Based on FAV and FCV, a criterion maximum concentration (CMC) and a criterion continuous concentration (CCC) for Fe, Pb, Ni, and Zn that are 37.2, 8.5, 82.5, and 152.4 μg L(-1) and 9.0, 2.0, 19.9, and 36.7 μg L(-1), respectively, were derived. The results of this study provide useful data for deriving national or local water quality criteria for Fe, Pb, Ni, and Zn based on aquatic biota in Malaysia. Based on LC(50) values, this study indicated that N. elinguis, M. lanchesteri, N. elinguis, and R. sumatrana were the most sensitive to Fe, Pb, Ni, and Zn, respectively. PMID:22919358

  19. Deriving Freshwater Quality Criteria for Iron, Lead, Nickel, and Zinc for Protection of Aquatic Life in Malaysia

    Directory of Open Access Journals (Sweden)

    M. Shuhaimi-Othman

    2012-01-01

    Full Text Available Freshwater quality criteria for iron (Fe, lead (Pb, nickel (Ni, and zinc (Zn were developed with particular reference to aquatic biota in Malaysia, and based on USEPA’s guidelines. Acute toxicity tests were performed on eight different freshwater domestic species in Malaysia which were Macrobrachium lanchesteri (prawn, two fish: Poecilia reticulata and Rasbora sumatrana, Melanoides tuberculata (snail, Stenocypris major (ostracod, Chironomus javanus (midge larvae, Nais elinguis (annelid, and Duttaphrynus melanostictus (tadpole to determine 96 h LC50 values for Fe, Pb, Ni, and Zn. The final acute value (FAV for Fe, Pb, Ni, and Zn were 74.5, 17.0, 165, and 304.9 μg L−1, respectively. Using an estimated acute-to-chronic ratio (ACR of 8.3, the value for final chronic value (FCV was derived. Based on FAV and FCV, a criterion maximum concentration (CMC and a criterion continuous concentration (CCC for Fe, Pb, Ni, and Zn that are 37.2, 8.5, 82.5, and 152.4 μg L−1 and 9.0, 2.0, 19.9, and 36.7 μg L−1, respectively, were derived. The results of this study provide useful data for deriving national or local water quality criteria for Fe, Pb, Ni, and Zn based on aquatic biota in Malaysia. Based on LC50 values, this study indicated that N. elinguis, M. lanchesteri, N. elinguis, and R. sumatrana were the most sensitive to Fe, Pb, Ni, and Zn, respectively.

  20. CROATIAN FRESHWATER FISHERIES IN 1996.

    Directory of Open Access Journals (Sweden)

    Mirko Turk

    1997-07-01

    Full Text Available Data on the production and fish catch according to species, on the surface of the fish ponds, on the means of fish catching and on the distribution of the production and the catch in 1996 is presented. The surface area used for production of fish has decreased by 1357 ha or 11.99%. The total fish amount has decreased by 1,921.00 tons or 29.76%. The feeding coefficient is 4 kg (33.33% bigger compared to the previous year. The amount of the fertilizer used has decreased by 18.79%. The fry carp growing ponds make up 5.99% of the total fish pond surfaces, the young carp ponds 21.13%, and the ponds with consumption fish 71.53%. The total fish amount in the carp ponds was 376 kg/ha, and in the trout ponds it was 146.6 tons/ha. The most produced fish species is the carp with 82.21 %, followed by the trout with 8.57%, the herbivorous fish with 4.78%, while all the other fish species make up 4.44% of the entire production. In the structure of herbivorous fish the grass carp is leading with 64,28%, followed by the big head carp with 26.02% and the silver carp with 9.70%. Compared to the previous year the production of the trout and tench has somewhat increased, while the production of all the other species of fish has decreased. Fish catch in open waters has increased by 19.23% in comparison to the previous year. In the production and catch of the total freshwater fish, carp made up 77.46%, the herbivorous fish made up 4.32%, trout 4.32%, sheat fish, pike perch and pike 2.99% and all other fish species 7.36%. As far as the distribution of production and catch is concerned, 46.91% were sold on the market, 39.19% were used for reproduction (stocking the fish farms, mortalities were 6.23%, and for personal use (sports fishing 7.67% was used. The number of fisheries workers has decreased by 17.75%, and the production per worker has also decreased by 26.62%, compared to the previous year. Average production per worker was 5.87 tons of fish.

  1. CROATIAN FRESHWATER FISHERIES IN 1997

    Directory of Open Access Journals (Sweden)

    Mirko Turk

    1998-10-01

    Full Text Available Data on the production and fish catch according to species, on the surface of the fish ponds, on the means of fish catching and on the distribution of the production and the catch in 1997 is presented. The surface area used for production of fish has decreased for 836 ha or 8.40%. The total fish amount was bigger for 477 tons, or 10,52%. The feeding coefficient is 2.6 kg decreased 35% for in comparison to the bigger compared to the previous year. The amount of the fertilizer used is bigger for 37.30%. The fry carp growing ponds make up 6.50% of the total fish pond surfaces, the young carp ponds 22.04/0, and the ponds with consumption fish 70.31%. The total amount in the carp ponds was 446 kg/ha, and in the trout ponds it was 160.8 tons/ha. The most produced fish species is the carp with 79.32%, followed by the trout with 11.50%, the herbivorous fish with 4.25%, while all the other fish species make up 4.93% of the entire production. In the structure of herbivorous fish the grass carp is leading with 69,23%, followed by the big head carp with 29.74% and the silver carp with 1.03%. Compared to the previous year the production of the carp, grass carp and tench is increased. Fish catch in open waters has decreased by 5.53% in comparison to the previous year. In the production and catch of the total freshwater fish, carp made up 75.34%, herbivorous fish made up 3.89%, trout 10.66%, sheat fish, pike perch and pike 2.70% and all other fish species 7.41%. As far as the distribution of production and catch of fish is concerned, 52,80% were sold on the market, 37.94% were used for reproduction (stocking the fish farms, mortality was 1.43%, and for personal use (sports fishing 7.83%. The number of fisheries workers has decreased for 8.17%, and the production per worker is bigger for 22.25%, compared to the previous year. Average production per worker was 7.17% tons of fish.

  2. Ecosystem Services : In Nordic Freshwater Management

    DEFF Research Database (Denmark)

    Magnussen, Kristin; Hasler, Berit; Zandersen, Marianne

    Human wellbeing is dependent upon and benefit from ecosystem services which are delivered by well-functioning ecosystems. Ecosystem services can be mapped and assessed consistently within an ecosystem service framework. This project aims to explore the use and usefulness of the ecosystem service...... framework in freshwater management, particularly water management according to the Water Framework Directive (WFD). There are several examples of how ecosystem services have been used in WFD related studies in all the Nordic countries. Most of them involve listing, describing and categorizing freshwater...... ecosystem services, while there are few comprehensive Cost Benefit Analyses and analyses of disproportionate costs that apply this framework. More knowledge about ecosystem services and the value of ecosystem services for freshwater systems is needed....

  3. Effects of Pollution on Freshwater Organisms.

    Science.gov (United States)

    Choudri, B S; Baawain, Mahad

    2016-10-01

    This review includes works published in the general scientific literature during 2015 on the effects of anthropogenic pollutants on freshwater organisms. It begins with two broad sections: research reviews and broad field studies and surveys. This is followed by reviews of research categorized in sections to reflect the pollutant class. These sections include wastewater, stormwater and non-point source pollution, nutrients, sediment cap materials and suspended clays, botanical extracts, surfactants, metals, persistent organic pollutants, pharmaceuticals, endocrine disruptors, pesticides, petroleum hydrocarbons and polycyclic aromatic hydrocarbons (PAHs), ionic liquids, and nanomaterials. The final section includes works describing innovations in the field of freshwater pollution research. PMID:27620107

  4. Radiation dose and countermeasure model for a decision support system on freshwater ecosystems contaminated with radionuclides

    International Nuclear Information System (INIS)

    With the participation of several European institutions The MOIRA project (A MOdel based computerised system for management support to Identify optimal remedial strategies for Restoring radionuclide contaminated Aquatic ecosystems, European Commission contract FI4P-CT96-0036) has developed a computerised Decision Support System that will allow decision makers to choose optimal intervention strategies for freshwater ecosystems with different radioactive contamination scenarios. An important factor for the decision analysis is the radiation dose resulting to humans and biota from the contamination. Not less important is to quantify the impact that intervention strategies may have on the potential resulting dose. With that aim, the system is incorporating a dose and countermeasure model, very flexible, that is able to estimate dose to the critical individuals and collective dose to the affected population, as well as maximum dose to fish species, representative of the threats to biota from radioactive contamination of water bodies. The model main characteristics are: Applicable to different water bodies (in principle lakes and rivers) contaminated with Cs-137 and/or Sr-90. The model is driven by the time series of radionuclide concentrations in the water, in the bottom sediments and fish (predator and prey species), which are the output from other environmental models of the MOIRA system. Main sub-models: individual and collective external dose and ingestion dose for 6 age groups; dose to fish. Countermeasures. External dose assessment takes into account exposure pathways as direct dose from the water body and dose from the shoreline deposits. The model makes use of external dose factors available in the literature, shielding factors applicable for the different situations considered, and mean exposure times. Countermeasures modelled: restriction of access to contaminated areas. For internal dose from ingestion, the exposure pathways considered are: ingestion of water

  5. Threatened and Endangered Freshwater Fish and Mussel Species Richness

    Data.gov (United States)

    U.S. Environmental Protection Agency — These data represent predicted current distributions of all US listed Threatened and Endangered freshwater fish and freshwater mussels in the Middle-Atlantic...

  6. CROATIAN FRESHWATER FISHERIES IN 1994

    Directory of Open Access Journals (Sweden)

    Mirko Turk

    1995-09-01

    Full Text Available Data on the production and catch of fish according to species, on the surface of the fish ponds, on the means of fish catching and on the distribution of the product and catch in 1994 is presented. The surface area used for production of fish has decreased by 274 ha or 2,51%. The total amount of fish has decreased by 1.263 tons or 14,78%. The highest production of fish was reached by the fish farm Donji Miholjac with 1.231 kg/ha. The feeding coefficient is 3,10 kg. Only on one fish farm was the feeding coefficient less than 2.0 kg (1,40 and on two large farms this coefficient was greater than 5,00 kg. The main fish food is still wheat followed by corn. The amount of fertilizer used was decreased by 14,40%. The fry carp growing ponds make up 0,92% of the surface area of the entire fish farm, the young carp ponds 21,77% and the culturing ponds for consumption fish 76,55%. The total amount of fish in the carp ponds was 660 kg/ha, and in the trout ponds it was 123.4 tons/ha. The carp is the highest produced fish with 80, 35%, then the herbivorous fish with 5,65 and all other fish make up 14% of the total production. In the structure of herbivorous fish the grass carp is leading with 54, 70%, followed by the big head carp with 25,54% and the silver carp with 19,76%. In comparison with the previous year the production of "all other fish- has significantly increased (287%, and sheat fish 18,90%, while the production of trench has decreased (71%. Fish catch in open waters has increased by 20,57% in comparison to the previous year. Carp made up 78,07% of the total production and catch of freshwater fish, the herbivorous fish made up 5,40%, trout 4,38%, the sheat fish, pike perch and pike 2,86% and all other fish species 9,28%. As far as the distribution of production and catch, 51,60% were sold on the market, 37,54% were used for reproduction (stocking the fish farms , mortalities were 6,35% and for personal use (sports fishing 4,50% was used. The number

  7. CROATIAN FRESHWATER FISHERIES IN 1995

    Directory of Open Access Journals (Sweden)

    Mirko Turk

    1996-06-01

    Full Text Available The data on the production and catch of fish according to sorts, pond ackerage, fishing means as well as the distribution of production and catch in 1995 have been stated in the paper. Ackerages used for the fish production have been increased by 1710 acres or 6.51%; total fish prinos* is less for 1,252 tons or 17.05%. The highest production of fish was reched by the fish farm Donji Miholjac with 859 kg/ha. A nutritive coefficient is 3.0 kg and it is less by 3.22% compared with the previous year. The nutritive coefficient is less than 2.0 kg in three fish-farms but it is greater than 4.0 kg in five large fish farms. Mostly corn but also wheat dominate in fish nutrition. The fertilizers consumption has been reduced by 14.53%. Of total pond ackerage, growing fish farms occupy 1.25%, new fish farms occupy 17.90% and consumptive fish farms occupy 79.64%. Total fish production in carp ponds is 507 kg/ha and 136.1 ton/ha in trout ponds. With 84.33%, carp is the mostly produced fish sorts, herbivore fish follow it with 3.89% and the production of all other fish makes 11.78% of the total. With 83.97%, grass carp takes the first place in the structure of herbivore fish. It is followed by the big head carp with 9.28% and silver carp with 6.75%. The trout production has been slightly increased by 6. 3%. Pike has appeared again and all other fish sorts has been reduced. Fish catch in open water has been increased by 7.06% compared with the previous year. When we sum up total production and catch of fresh-water fish, we can conclude that carp contributes with 81.08%; herbivore fish with 3.67%; trouts with 5.53%; sheat-fish, pike-perch and pike with 2.74% and all other fish sorts with 6.98%. As to the distribution of production and catch, there has been 49.02% sold on markets, 38.02% has been spent on farm reproduction (set back in ponds, the percentage of mortalities is 7.90%. Sport fishers have spent 5.06% of fish. The number of employees has been reduced

  8. Cretaceous biota of the Triângulo Mineiro region (Brazil: A review of recent finds

    Directory of Open Access Journals (Sweden)

    Candeiro, C. R. A.

    2007-06-01

    Full Text Available The Bauru Group (Adamantina, Uberaba, and Marília Formations crop out in the Triângulo Mineiro region, Minas Gerais State, Brazil, and yield a rich continental biota. Invertebrate and vertebrate taxa from underlying and overlying strata, as well as biostratigraphical correlations with other fossil sites in Argentina, suggest an Upper Cretaceous age for this biota. The diversity of the fossil assemblage recorded in these formations is summarized here and includes: frogs, lizards, crocodiles, titanosaurs, abelisaurid and carcharodontosaurid dinosaurs. This fossil assemblage provides important clues to understand faunas from other southern landmasses, particularly those from the Cretaceous of the African continent.Los afloramientos del Grupo Bauru (formaciones Adamantina, Uberaba y Marília en la región del Triângulo Mineiro, Provincia de Minas Gerais, Brasil, posee un rico contenido de biota continental. Los taxa de invertebrados y vertebrados de estos estratos, así como las correlaciones biostratigráficas con otros yacimientos fósiles de Argentina, sugieren una edad del Cretácico Tardío. La diversidad de la asociación fósil registrada en las formaciones del Triângulo Mineiro se resume en el presente trabajo e incluye: sapos, lagartos, tortugas, cocodrilianos, titanosaurideos, dinosaurios abelisaurideos y carcharodontosaurideos. Esta asociación es importante para la comprensión de las faunas del sur de América y también de las del Cretácico de África.

  9. INSTITUIÇÕES DE PESQUISA EM MEIO AMBIENTE: o caso do BIOTA e do LBA

    OpenAIRE

    2010-01-01

    O questionamento que se faz neste artigo é se programas de pesquisa em meio ambiente podem ser considerados e analisados como instituições. Para analisar este questionamento não basta só explorar em termos teóricos a relação programas de pesquisa-instituições, mas cotejar a analise teórica com estudo de caso. Este artigo fará esta analise a partir de dois programas de pesquisa em meio ambiente o BIOTA e o LBA. Desta analise tem-se que o desenho ou formato do programa é essencial para que se ...

  10. Lack of observed impacts of gas production of Bongkot Field, Thailand on marine biota

    Energy Technology Data Exchange (ETDEWEB)

    Windom, H.L. [Skidaway Institute of Oceanography, Savannah, GA (United States); Cranmer, G. [Metoc plc, Liphook (United Kingdom)

    1998-10-01

    The impact of metal releases, associated with gas production, on biota in the Lower Gulf of Thailand was evaluated based on metal concentrations in finfish and on the composition of sediment fauna. Results indicate that metal concentrations, particularly Hg, in species of snapper and grouper collected near the gas production platform were not significantly different from those of the same species of fish caught from the regional, presumably non-impacted, fishery. Also, there were no significant differences in faunal communities in sediments collected near petroleum production activities from those in sediments collected at remote sites. (author)

  11. Geological dates and molecular rates: rapid divergence of rivers and their biotas.

    Science.gov (United States)

    Waters, Jonathan M; Rowe, Diane L; Apte, Smita; King, Tania M; Wallis, Graham P; Anderson, Leigh; Norris, Richard J; Craw, Dave; Burridge, Christopher P

    2007-04-01

    We highlight a novel molecular clock calibration system based on geologically dated river reversal and river capture events. Changes in drainage pattern may effect vicariant isolation of freshwater taxa, and thus provide a predictive framework for associated phylogeographic study. As a case in point, New Zealand's Pelorus and Kaituna rivers became geologically isolated from the larger Wairau River system 70 to 130 kyr BP. We conducted mitochondrial DNA phylogeographic analyses of two unrelated freshwater-limited fish taxa native to these river systems (Gobiomorphus breviceps, n = 63; Galaxias divergens, n = 95). Phylogenetic analysis of combined control region and cytochrome b sequences yielded reciprocally monophyletic clades of Pelorus-Kaituna and Wairau haplotypes for each species. Calibrated rates of molecular change based on this freshwater vicariant event are substantially faster than traditionally accepted rates for fishes but consistent with other recent inferences based on geologically young calibration points. A survey of freshwater phylogeographic literature reveals numerous examples in which the ages of recent evolutionary events may have been substantially overestimated through the use of "accepted" calibrations. We recommend that--wherever possible--biologists should start to reassess the conclusions of such studies by using more appropriate molecular calibrations derived from recent geological events. PMID:17464882

  12. Mathematical Explorations: Freshwater Scarcity: A Proportional Representation

    Science.gov (United States)

    King, Alessandra

    2014-01-01

    Middle school students' mathematical understanding benefits from connecting mathematics to other content areas in the curriculum. This month's activity explores the issue of the scarcity of freshwater, a natural resource (activity sheets are included). This activity concentrates on the critical areas mentioned in the Common Core State…

  13. Effects of Pollution on Freshwater Invertebrates.

    Science.gov (United States)

    Buikema, A. L., Jr.; Herricks, E. E.

    1978-01-01

    Presents a literature review of the effects of pollution on freshwater invertebrates, covering publications of 1976-77. Some of the areas covered are: (1) toxicant effects on invertebrates; (2) microcosm and community effects, and (3) biological control of aquatic life. A list of 123 references is also presented. (HM)

  14. Sulfate reduction and methanogenesis at a freshwater

    DEFF Research Database (Denmark)

    Iversen, Vibeke Margrethe Nyvang; Andersen, Martin Søgaard; Jakobsen, Rasmus

    is enriched in dissolved sulfide, methane and bicarbonate. Under normal conditions the seawater-freshwater interface is found at a depth of 4 m at the coastline and reaches the bottom of the aquifer 40 m inland. However, occasional flooding of the area occurs, introducing sulfate to the aquifer. Groundwater...

  15. Evaluation of multixenobiotic resistance in dreissenid mussels as a screening tool for toxicity in freshwater sediments.

    Science.gov (United States)

    Ács, A; Imre, K; Kiss, Gy; Csaba, J; Győri, J; Vehovszky, Á; Farkas, A

    2015-05-01

    The multixenobiotic defense mechanism (MXR) in aquatic organisms was recognized as a first-line defense system, and its potential use as an early biomarker of exposure to environmental stress has raised attention in the last two decades. To evaluate the relevance of this biomarker in the freshwater mussel Dreissena polymorpha, we studied its responsiveness within laboratory exposures to contaminants sequestered in freshwater sediments affected by moderate anthropogenic impact. The effectiveness of this biomarker was assessed by comparing the MXR-transporter activities determined in bivalves first with toxicity scores recorded with the D. rerio embryo developmental assay. Both bioassays were applied in the sediment contact test format. As a second evaluation approach, MXR activities determined in exposed mussels were compared with sediment-contamination data integrated into toxic units on the basis of acute toxicity to Daphnia magna. In D. polymorpha subjected to acute exposure with moderately polluted sediments, we detected limited (22-33 %) but statistically significant induction of MXR activity. Mean MXR activities significantly correlated with TU values computed for test sediments. MXR activities in mussels showed strong positive correlation with the metal load of sediments and proved to be unrelated to the contamination with polycyclic aromatic compounds. MXR activity in laboratory-exposed mussels showed low variability within treatments and thus reliably reflected even low contaminant differences between the negative reference and moderately polluted harbor sediments. The strong correlation found in this study between the MXR-transporter activity in exposed mussels and environmentally realistic sediment contamination underscores the fairly good sensitivity of this biomarker in laboratory testing conditions to signal the bioavailability of sediment bound contaminants, and it may also anticipate even the incidence of toxicity to biota. PMID:25801701

  16. Freshwater flux to Sermilik Fjord, SE Greenland

    Directory of Open Access Journals (Sweden)

    S. H. Mernild

    2010-10-01

    Full Text Available Terrestrial inputs of freshwater flux to Sermilik Fjord, SE Greenland, were estimated, indicating ice discharge to be the dominant source of freshwater. A freshwater flux of 40.4 ± 4.9×109 m3 y−1 was found (1999–2008, with an 85% contribution originated from ice discharge (65% alone from Helheim Glacier, 11% from terrestrial surface runoff (from melt water and rain, 3% from precipitation at the fjord surface area, and 1% from subglacial geothermal and frictional melting due to basal ice motion. The results demonstrate the dominance of ice discharge as a primary mechanism for delivering freshwater to Sermilik Fjord. Time series of ice discharge for Helheim Glacier, Midgård Glacier, and Fenris Glacier were calculated from satellite-derived average surface velocity, glacier width, and estimated ice thickness, and fluctuations in terrestrial surface freshwater runoff were simulated based on observed meteorological data. These simulations were compared and bias corrected against independent glacier catchment runoff observations. Modeled runoff to Sermilik Fjord was variable, ranging from 2.9 ± 0.4×109 m3 y−1 in 1999 to 5.9 ± 0.9×109 m3 y−1 in 2005. The sub-catchment runoff of the Helheim Glacier region accounted for 25% of the total runoff to Sermilik Fjord. The runoff distribution from the different sub-catchments suggested a strong influence from the spatial variation in glacier coverage, indicating high runoff volumes, where glacier cover was present at low elevations.

  17. Marine incursion: the freshwater herring of Lake Tanganyika are the product of a marine invasion into west Africa.

    Directory of Open Access Journals (Sweden)

    Anthony B Wilson

    Full Text Available The spectacular marine-like diversity of the endemic fauna of Lake Tanganyika, the oldest of the African Great Lakes, led early researchers to suggest that the lake must have once been connected to the ocean. Recent geophysical reconstructions clearly indicate that Lake Tanganyika formed by rifting in the African subcontinent and was never directly linked to the sea. Although the Lake has a high proportion of specialized endemics, the absence of close relatives outside Tanganyika has complicated phylogeographic reconstructions of the timing of lake colonization and intralacustrine diversification. The freshwater herring of Lake Tanganyika are members of a large group of pellonuline herring found in western and southern Africa, offering one of the best opportunities to trace the evolutionary history of members of Tanganyika's biota. Molecular phylogenetic reconstructions indicate that herring colonized West Africa 25-50MYA, at the end of a major marine incursion in the region. Pellonuline herring subsequently experienced an evolutionary radiation in West Africa, spreading across the continent and reaching East Africa's Lake Tanganyika during its early formation. While Lake Tanganyika has never been directly connected with the sea, the endemic freshwater herring of the lake are the descendents of an ancient marine incursion, a scenario which may also explain the origin of other Tanganyikan endemics.

  18. PENGGUNAAN EKSTRAK BIOTA LAUTAGLAOPHENIA SP. UNTUK MENGENDALIKANFUSARIUM OXYSPORUM F.SP.VANILLAE PENYEBAB BUSUK BATANG VANILI

    Directory of Open Access Journals (Sweden)

    I KETUT SUADA

    2012-11-01

    Full Text Available The Use of Aglaophenia sp. Marine Biota Extract to Control Fusarium oxysporum f. sp. vanillae, a Pathogen of Vanilla Stem Rot The use of marine biota for organic fungicide material has enormous potential to be developed. The organic fungicide was directed to substitute synthetic fungicide for vanilla cultivation. Application of synthetic fungicide degraded environmental quality, therefore its applications does not support sustainable agriculture. The objective of this research was to know the potence of Aglaopheniain suppressing the growth of F. oxysporum f. sp.vanillae, the pathogen of vanilla stem rot. The research was done in green house in order to find the best substance for formulation of the extract. The substances screened were water, tween-80, and detergents with two different concentrations. Subsequently, two best formulas were chosen to apply in endemic area in Tabanan. The green house and field trial research used Randomized Completely Design with three and five replications respectively. Results showed that tween was the best substance used for formulation and concentration of 0.2% was better than other concentrations. The extract diluted in tween-80 on the concentration of 0.2% showed the lowest rot on stem, longest shoot, and the most leaves on vanilla shoot. Because of its significant performance, the 0.1% extract ofAglaopheniain 0.1% tween-80 was proposed to be the best formula to suppress the vanilla stem rot disease.

  19. Climate-change impacts on sandy-beach biota: crossing a line in the sand.

    Science.gov (United States)

    Schoeman, David S; Schlacher, Thomas A; Defeo, Omar

    2014-08-01

    Sandy ocean beaches are iconic assets that provide irreplaceable ecosystem services to society. Despite their great socioeconomic importance, beaches as ecosystems are severely under-represented in the literature on climate-change ecology. Here, we redress this imbalance by examining whether beach biota have been observed to respond to recent climate change in ways that are consistent with expectations under climate change. We base our assessments on evidence coming from case studies on beach invertebrates in South America and on sea turtles globally. Surprisingly, we find that observational evidence for climate-change responses in beach biota is more convincing for invertebrates than for highly charismatic turtles. This asymmetry is paradoxical given the better theoretical understanding of the mechanisms by which turtles are likely to respond to changes in climate. Regardless of this disparity, knowledge of the unique attributes of beach systems can complement our detection of climate-change impacts on sandy-shore invertebrates to add rigor to studies of climate-change ecology for sandy beaches. To this end, we combine theory from beach ecology and climate-change ecology to put forward a suite of predictive hypotheses regarding climate impacts on beaches and to suggest ways that these can be tested. Addressing these hypotheses could significantly advance both beach and climate-change ecology, thereby progressing understanding of how future climate change will impact coastal ecosystems more generally.

  20. Soil cultivation in vineyards alters interactions between soil biota and soil physical and hydrological properties

    Science.gov (United States)

    Zaller, Johann G.; Buchholz, Jacob; Querner, Pascal; Winter, Silvia; Kratschmer, Sophie; Pachinger, Bärbel; Strauss, Peter; Bauer, Thomas; Stiper, Katrin; Potthoff, Martin; Guernion, Muriel; Scimia, Jennifer; Cluzeau, Daniel

    2016-04-01

    Several ecosystem services provided by viticultural landscapes result from interactions between soil organisms and soil parameters. However, to what extent different soil cultivation intensities in vineyards compromise soil organisms and their interactions between soil physical and hydrological properties is not well understood. In this study we examined (i) to what extent different soil management intensities affect the activity and diversity of soil biota (earthworms, Collembola, litter decomposition), and (ii) how soil physical and hydrological properties influence these interactions, or vice versa. Investigating 16 vineyards in Austria, earthworms were assessed by hand sorting, Collembola via pitfall trapping and soil coring, litter decomposition by using the tea bag method. Additionally, soil physical (water infiltration, aggregate stability, porosity, bulk density, soil texture) and chemical (pH, soil carbon content, cation exchange capacity, potassium, phosphorus) parameters were assessed. Results showed complex ecological interactions between soil biota and various soil characteristics altered by management intensity. These investigations are part of the transdisciplinary BiodivERsA project VineDivers and will ultimately lead into management recommendations for various stakeholders.

  1. Persistence of spilled oil on shores and its effects on biota

    Science.gov (United States)

    Irvine, G.V.; ,

    2000-01-01

    Over two million tonnes of oil are estimated to enter the world's oceans every year. A small percentage, but still a large volume, of this oil strands onshore, where its persistence is governed primarily by the action of physical forces. In some cases, biota influence the persistence of stranded oil or the rate of its weathering. Oil's deleterious effects on biota are frequently related to the persistence and degree of weathering of the oil, with long-lasting effects in low-energy environments such as salt marshes and coastal mangroves, or in higher-energy environments where oil is sequestered. However, an oil spill can have disproportionately large biological effects when it affects key species or processes (e.g., structurally important species, predators, prey, recruitment, or succession). In these cases, the continuing presence of oil is not always a prerequisite for continuing biological effects. There are relatively few long-term studies of the effects of oil spills; data from these suggest that oil can persist for decades in some environments or situations, and that biological effects can be equally persistent. Broad-based, integrated studies have been the most revealing in terms of the importance of direct and indirect effects, spillover effects between different parts of the environment, and continuing linkages between residual oil and biologic effects. Clean-up and treatment techniques applied to spilled or stranded oil can also have significant, long-lasting effects and need to be carefully evaluated prior to use.

  2. Study of the behaviour of transuranics and possible chemical homologues in Lake Michigan water and biota

    International Nuclear Information System (INIS)

    Concentration factors for Pu, Am and U in Lake Michigan biota are compared to those of a number of stable trace elements that have short residence times in Lake Michigan water. The relative order of uptake for these nuclides in Lake Michigan biota is Am>Pu much>U. Evidence is summarized which suggests that the predominant oxidation state of 239, 240Pu in Lake Michigan water is 4+. Concentrations of 239, 240Pu in net plankton, filterable particulate matter, sediment trap, and benthic floc samples indicate that sorption by biogenic detritus, and settling of this material, can account for the reduced concentration of 239, 240Pu observed in surface waters during summer stratification, but that deposition into the sediments is primarily non-biological. Concentrations of 7Be, 144Ce and 137Cs in sediment trap samples show the effect of spring convective mixing and demonstrate the resuspension of mineral-rich surficial sediments during the summer months. The effect on the concentration of dissolved plutonium in the water column, of varying degrees of resuspension of sedimentary floc, is described using a simple mass-action model. A radiochemical method for the determination of americium and uranium in Lake Michigan environmental samples is also presented. (author)

  3. Differentiated availability of geochemical mercury pools controls methylmercury levels in estuarine sediment and biota.

    Science.gov (United States)

    Jonsson, Sofi; Skyllberg, Ulf; Nilsson, Mats B; Lundberg, Erik; Andersson, Agneta; Björn, Erik

    2014-08-20

    Neurotoxic methylmercury (MeHg) formed from inorganic divalent mercury (Hg(II)) accumulates in aquatic biota and remains at high levels worldwide. It is poorly understood to what extent different geochemical Hg pools contribute to these levels. Here we report quantitative data on MeHg formation and bioaccumulation, in mesocosm water-sediment model ecosystems, using five Hg(II) and MeHg isotope tracers simulating recent Hg inputs to the water phase and Hg stored in sediment as bound to natural organic matter or as metacinnabar. Calculations for an estuarine ecosystem suggest that the chemical speciation of Hg(II) solid/adsorbed phases control the sediment Hg pool's contribution to MeHg, but that input of MeHg from terrestrial and atmospheric sources bioaccumulates to a substantially greater extent than MeHg formed in situ in sediment. Our findings emphasize the importance of MeHg loadings from catchment runoff to MeHg content in estuarine biota and we suggest that this contribution has been underestimated.

  4. Physical processes in freshwater ecosystems

    International Nuclear Information System (INIS)

    In the present paper the main methodological approaches to model the physical processes controlling the migration of radionuclides through water ecosystems are presented and discussed. These processes include the dispersion and the transport through the water and the migration from and to the bottom sediments caused by the settling and the re-suspension of contaminated particles of suspended matter. The equations that control the above processes and that are used by most existing state-of-the-art models are listed and briefly discussed and motivated. Values of the parameters in the equations have been selected following a review of information available from the scientific literature. (author)

  5. CROATIAN FRESHWATER FISHERY IN 2001 and 2002

    Directory of Open Access Journals (Sweden)

    Irena Jahutka

    2003-09-01

    Full Text Available For each segment of freshwater fisheries — freshwater aquaculture, commercial and sport and recreational fisheries — there is a legal obligation for data submission to the Ministry of agriculture and forestry, Directorate of fisheries. Within the segments of commercial and sport and recreational fisheries the data submission obligation refers to the period beginning with the year 2003, while in the segment of aquaculture that obligation includes also the year 2002. Data collected for freshwater aquaculture contain the information on production of freshwater fish, total production areas, food, fertilizers and subsidies for freshwater fish farming. Data collected for commercial and sport and recreational fisheries contain the information on catch quantities and number of commercial and sport and recreational fishermen. Freshwater fish production in the year 2001 was 5,549. 50 tons, while the total fresh water fish production in the year 2002 decreased for 1.00% compared to the previous year, amounting to 5,501.07 tons. Although total fresh water fish production constantly decreases comparing to previous years, trout production has increased and the maximum production was noted in the year 2002. Total area of the freshwater fish farms in the year 2001 increased compared to the year 2000 for 2.14% amounting to 11,880.41 ha. Actual production area slightly increased in comparison to the previous year as well and amounted to 9,214.11 ha. In the year 2002 total area of freshwater fish farms was 11,491.29 ha, and 72.13% of that figure was the actual production area, that is 8,288.27 ha. Production per unit area in the year 2001 was 485.31 kg/ha for warm–water species and 280.44 t/ha for cold–water species. In the year 2002 production per unit area for warm–water species was 462.95 kg/ha, and for cold–water species 315.26 t/ha. During the year 2001, in total, 10,575.82 t of food was spent and 1,891 tons of fertilizers and lime, while in the

  6. The effect of water hardness on the toxicity of uranium to a tropical freshwater alga Chlorella sp.

    Science.gov (United States)

    Charles, Amanda L; Markich, Scott J; Stauber, Jennifer L; De Filippis, Lou F

    2002-10-01

    Uranium (U) derived from mining activities is of potential ecotoxicological concern to freshwater biota in tropical northern Australia. Few data are available on the effects of water hardness (Ca and/or Mg), which is elevated in U mine wastewaters, on the toxicity and bioavailability of U to freshwater biota, particularly algae. This study determined the effect of water hardness (8, 40, 100 and 400 mg CaCO(3) x l(-1), added as calcium (Ca) and magnesium (Mg) sulphate) on the toxicity (72 h growth rate inhibition) of U to the unicellular green alga, Chlorella sp., in synthetic freshwater, at constant pH (7.0) and alkalinity (8 mg CaCO(3) x l(-1)), similar in chemical composition to sandy coastal streams in tropical northern Australia. A 50-fold increase in water hardness resulted in a 5-fold decrease (Phardness includes: (i) competition between U and Ca and/or Mg for binding sites on the cell surface; and (ii) a change in U speciation, and hence, bioavailability. Results showed that extracellular (cell-surface) and intracellular U concentrations significantly (Phardness increased from 8 to 400 mg CaCO(3)x l(-1). Calculation of U speciation using the geochemical model HARPHRQ showed that there were no significant (P>0.05) differences in the predicted speciation (% distribution) of U amongst the four water hardness levels. The reduction in U toxicity with increasing water hardness was most likely due to competition between U and Ca and/or Mg for binding sites on the algal cell surface. The minimum detectable effect concentrations of U were approximately 3 and 24 times higher (at 8 and 400 mg CaCO(3)x l(-1) hardness, respectively) than the national interim U guideline value (0.5 micro g x l(-1)) for protecting aquatic ecosystems. Overall, the results reinforce the need for a more flexible U guideline based on a hardness-dependent algorithm, which may allow environmental managers to relax the national guideline for U on a site-specific basis.

  7. The legacy of a vanished sea: a high level of diversification within a European freshwater amphipod species complex driven by 15 My of Paratethys regression.

    Science.gov (United States)

    Mamos, Tomasz; Wattier, Remi; Burzyński, Artur; Grabowski, Michał

    2016-02-01

    The formation of continental Europe in the Neogene was due to the regression of the Tethys Ocean and of the Paratethys Sea. The dynamic geology of the area and repetitious transitions between marine and freshwater conditions presented opportunities for the colonization of newly emerging hydrological networks and diversification of aquatic biota. Implementing mitochondrial and nuclear markers in conjunction with a large-scale sampling strategy, we investigated the impact of this spatiotemporal framework on the evolutionary history of a freshwater crustacean morphospecies. The Gammarus balcanicus species complex is widely distributed in the area previously occupied by the Paratethys Sea. Our results revealed its high diversification and polyphyly in relation to a number of other morphospecies. The distribution of the studied amphipod is generally characterized by very high local endemism and divergence. The Bayesian time-calibrated reconstruction of phylogeny and geographical distribution of ancestral nodes indicates that this species complex started to diversify in the Early Miocene in the central Balkans, partially in the shallow epicontinental sea. It is possible that there were several episodes of inland water colonization by local brackish water lineages. Subsequent diversification within clades and spread to new areas could have been induced by Alpine orogeny in the Miocene/Pliocene and, finally, by Pleistocene glaciations. The present distribution of clades, in many cases, still reflects Miocene palaeogeography of the area. Our results point out that investigations of the historical aspect of cryptic diversity in other taxa may help in a general understanding of the origins of freshwater invertebrate fauna of Europe.

  8. Proceedings of the workshop on 'effect of radiation on non-human biota'

    International Nuclear Information System (INIS)

    Safety assessment and protection for the radiation exposure were so far mainly based on the radiation effects on human health, because it has been generally recognized that, when human beings are protected, other environmental life, at least in the level of species or groups, will be protected from the radiation hazards, even if individuals may be affected. Recently, with increasing concern on environmental protection, a new framework of radiation protection has been proposed, where non-human biota as well as human beings is included. Researches on the environmental radiation protection need a contribution of multi-disciplinary researchers as similar to the other environmental sciences. Especially, a research field on the biological effect of radiation on non-human biota is fundamental and essential. Therefore, we planned the Workshop entitled Effect of Radiation on the Non-human Biota this time. All the 13 papers presented at the entitled meeting are indexed individually. (J.P.N.)

  9. Mesozooplankton affinities in a recovering freshwater estuary

    Science.gov (United States)

    Chambord, Sophie; Maris, Tom; Colas, Fanny; Van Engeland, Tom; Sossou, Akoko-C.; Azémar, Frédéric; Le Coz, Maïwen; Cox, Tom; Buisson, Laetitia; Souissi, Sami; Meire, Patrick; Tackx, Michèle

    2016-08-01

    Water quality of the Scheldt estuary (Belgium/The Netherlands) has considerably improved in recent years, especially in the upstream, freshwater reaches. Within the zooplankton community, the copepod Eurytemora affinis, typically abundant in brackish water and quasi-absent from freshwater before 2007, has since substantially developed in the latter, where it now represents 90% of the crustacean mesozooplankton community. Simultaneously, cyclopoid copepod abundance has greatly decreased, while cladoceran abundance did not change. The study aim was: 1) to verify if the zooplankton community described for the period 2007-2009 by Mialet et al. (2011) has stabilized until present, and 2) to look for the environmental conditions favouring E. affinis development and causing changes in the upstream freshwater zooplankton community. The 2002-2012 temporal evolution of the zooplankton distribution at three stations in the upstream freshwater Scheldt estuary was analyzed. Water quality remained better after 2007 than before, and some factors revealed continuous improvement in annual mean concentrations (e.g. increase in O2, decrease in BOD5 and NH4sbnd N concentration). The increase in oxygen and the decrease in NH4sbnd N concentration, together with low discharge during summer were the main environmental factors explaining the development and timing of E. affinis in the upstream freshwater reach. In this reach, E. affinis maximal abundance is shifted to higher temperatures (summer) compared to its typical maximum spring abundance peak in the brackish zone of the Scheldt estuary and in most temperate estuaries. The changes in zooplankton community followed a temporal and spatial gradient induced by the spatio-temporal evolution of water quality improvement. The most downstream station (3) allowed E. affinis development (oxygen concentration > 4 mg L-1; NH4sbnd N concentration oxygen, etc.), there is no clear cause for their decline. Water quality improvement in the freshwater

  10. Polychlorinated biphenyls in freshwater salmonids from the Kerguelen Islands in the Southern Ocean

    International Nuclear Information System (INIS)

    The Subantarctic Kerguelen Islands (49oS, 70oE) contain freshwater ecosystems among the most isolated in the world. Concentrations of polychlorinated biphenyls (PCBs) were assessed in the muscle of 48 brook trout and 38 brown trout caught during summer and spring 2006 in the rivers, lakes and ponds of Kerguelen. The sum of 29 PCBs averaged 404 and 358 ng g-1 lipid, and dioxin-like PCB was 19 and 69 ng g-1 lipid, in brook and brown trout, respectively. The values showed a high variability and some fish accumulated PCBs at levels similar to those of fish from impacted areas. While inter-sex differences were limited, the season and the morphotype appeared to have the most influence. Fish captured in summer had muscle PCB concentrations about three times higher than those caught in spring and the 'river' morphotype of brook trout showed the highest PCB levels. - Highlights: → First assessment of PCB contamination of biota in Kerguelen Islands, Sub-Antarctica. → PCB bioaccumulation level in trout varies from very high to undetectable. → Habitat and morphotype are the most influential factors on the variability. → Distribution pattern of PCBs in the muscle of fish is morphotype dependent. - Salmonids in hydrosystems of the Kerguelen Islands (Southern Ocean) show a high PCB bioaccumulation.

  11. Short-term effects of small dam removal on freshwater mussel assemblage

    Science.gov (United States)

    Heise, Ryan J.; Cope, W. Gregory; Kwak, Thomas J.; Eads, Chris B.

    2013-01-01

    Dam removal is increasingly used to restore lotic habitat and biota, but its effects on freshwater mussels (family Unionidae) are not well known. We conducted a four-year study to assess short-term effects on mussels after removal of a small hydropower dam on the Deep River (Cape Fear River drainage), North Carolina, USA, in 2006. We conducted annual pre- and post-removal monitoring of mussel density, richness, and survival (post removal only) with transect surveys and quadrat excavation, and assessed changes in substrate composition at two impact sites (tailrace and impoundment) and two reference sites. Before-after-control-impact (BACI) analyses of variance did not detect a significant change in mussel density (total or individually for the three most abundant species), species richness, Eastern Elliptio (Elliptio complanata) mean length, or substrate composition in the tailrace or drained impoundment following dam removal. Apparent annual survival estimates of Eastern Elliptio at the tailrace site did not differ among sampling periods and were similar to control sites. We observed minimal mussel mortality from stranding in the dewatered reservoir. These results demonstrate that adverse short-term impacts of dam removal on downstream mussel assemblages can be minimized with appropriate planning, timing, and removal techniques, but additional monitoring is warranted to determine long-term effects on mussels within the restored river reach.

  12. River dolphins can act as population trend indicators in degraded freshwater systems.

    Science.gov (United States)

    Turvey, Samuel T; Risley, Claire L; Barrett, Leigh A; Yujiang, Hao; Ding, Wang

    2012-01-01

    Conservation attention on charismatic large vertebrates such as dolphins is often supported by the suggestion that these species represent surrogates for wider biodiversity, or act as indicators of ecosystem health. However, their capacity to act as indicators of patterns or trends in regional biodiversity has rarely been tested. An extensive new dataset of >300 last-sighting records for the Yangtze River dolphin or baiji and two formerly economically important fishes, the Yangtze paddlefish and Reeves' shad, all of which are probably now extinct in the Yangtze, was collected during an interview survey of fishing communities across the middle-lower Yangtze drainage. Untransformed last-sighting date frequency distributions for these species show similar decline curves over time, and the linear gradients of transformed last-sighting date series are not significantly different from each other, demonstrating that these species experienced correlated population declines in both timing and rate of decline. Whereas species may be expected to respond differently at the population level even in highly degraded ecosystems, highly vulnerable (e.g. migratory) species can therefore display very similar responses to extrinsic threats, even if they represent otherwise very different taxonomic, biological and ecological groupings. Monitoring the status of river dolphins or other megafauna therefore has the potential to provide wider information on the status of other threatened components of sympatric freshwater biotas, and so represents a potentially important monitoring tool for conservation management. We also show that interview surveys can provide robust quantitative data on relative population dynamics of different species. PMID:22666410

  13. Use of Pyrogenic Carbon Geosorbents to Decrease the Mobility and Bioavailability of Pharmaceuticals in the Soil-Water-Biota Continuum

    Science.gov (United States)

    Liu, Cheng-Hua; Zhang, Yingjie; Bhalsod, Gemini; Chuang, Ya-Hui; Boyd, Stephen; Teppen, Brian; Tiedje, James; Li, Hui; Zhang, Wei

    2016-04-01

    Pharmaceuticals are emerging contaminants widely detected in soil and water environments, and concerns are mounting over their potential impact on human and ecosystem health. In particular, overuse of antibiotics (an important group of pharmaceuticals) in human medicine and animal agriculture and rapid emergence of antibiotic resistant bacteria on a global scale are threatening the health of humans, animals, and the environment. We have investigated interactions of pharmaceuticals with pyrogenic carbon geosorbents (e.g., biohar and activated carbon), bacteria, and vegetable crops in order to better understand sorption, uptake, and translocation of pharmaceuticals in the soil-water-biota continuum. Sorption of antibiotics by biochars was studied to assess the effect of biochar soil amendment in reducing the transport and bioavailability of antibiotics. Pyrogenic carbonaceous materials such as biochars and activated carbon had strong sorption capacities for antibiotics, and drastically lowed the uptake of antibiotics by an Escherichia coli, therefore demonstrating soil amendment with pyrogenic carbon geosorbents as an effective remediation strategy to reduce antibiotic transport and selection pressure for antibiotic resistant bacteria. Additionally, because consuming pharmaceutical-tainted food is a direct human exposure pathway, it is critical to investigate the residue levels of pharmaceuticals in food crops grown in contaminated soils or irrigated with reclaimed water. Therefore, we have studied the uptake and accumulations of pharmaceuticals in greenhouse-grown lettuce under overhead or surface irrigations. Preliminary results indicate that pharmaceuticals of large molecular weight and low water solubility had greater concentrations in lettuce shoots under overhead irrigation than surface irrigation. Pharmaceuticals of low molecular weight and high water solubility are less clearly influenced by irrigation methods. These results implies that irrigation scheme

  14. Plant diversity surpasses plant functional groups and plant productivity as driver of soil biota in the long term.

    Directory of Open Access Journals (Sweden)

    Nico Eisenhauer

    Full Text Available BACKGROUND: One of the most significant consequences of contemporary global change is the rapid decline of biodiversity in many ecosystems. Knowledge of the consequences of biodiversity loss in terrestrial ecosystems is largely restricted to single ecosystem functions. Impacts of key plant functional groups on soil biota are considered to be more important than those of plant diversity; however, current knowledge mainly relies on short-term experiments. METHODOLOGY/PRINCIPAL FINDINGS: We studied changes in the impacts of plant diversity and presence of key functional groups on soil biota by investigating the performance of soil microorganisms and soil fauna two, four and six years after the establishment of model grasslands. The results indicate that temporal changes of plant community effects depend on the trophic affiliation of soil animals: plant diversity effects on decomposers only occurred after six years, changed little in herbivores, but occurred in predators after two years. The results suggest that plant diversity, in terms of species and functional group richness, is the most important plant community property affecting soil biota, exceeding the relevance of plant above- and belowground productivity and the presence of key plant functional groups, i.e. grasses and legumes, with the relevance of the latter decreasing in time. CONCLUSIONS/SIGNIFICANCE: Plant diversity effects on biota are not only due to the presence of key plant functional groups or plant productivity highlighting the importance of diverse and high-quality plant derived resources, and supporting the validity of the singular hypothesis for soil biota. Our results demonstrate that in the long term plant diversity essentially drives the performance of soil biota questioning the paradigm that belowground communities are not affected by plant diversity and reinforcing the importance of biodiversity for ecosystem functioning.

  15. Changes to the ocular biota with time in extended- and daily-wear disposable contact lens use.

    Science.gov (United States)

    Stapleton, F; Willcox, M D; Fleming, C M; Hickson, S; Sweeney, D F; Holden, B A

    1995-11-01

    Gram-negative bacteria may play a role in the etiology of certain soft contact lens (SCL)-related diseases. Contact lens (CL) wear may modify the normal ocular biota, providing a more favorable environment for potential pathogens. This study reports temporal changes in ocular biota in daily-wear (DW) and extended-wear (EW) disposable SCL use in experienced and neophyte wearers. Lid margin and bulbar conjunctival biota were sampled prior to CL fitting in 26 previous DW SCL users, 18 previous EW SCL users, and 26 neophytes. Wearers were fitted with an etafilcon A CL in one eye and a polymacon CL in the fellow eye. Lenses were worn on a daily basis by the 26 previous DW SCL wearers and on an EW basis by the remaining 44 subjects. The ocular biota was further sampled after 1, 3, 6, 9, and 12 months of wear. The ocular biota consisted of coagulase-negative staphylococci, Corynebacterium spp., Micrococcus spp., and Propionibacterium spp. Potential pathogens were rarely isolated at baseline. No significant trend of increasing ocular colonization was shown for extended CL wear. Lid and conjunctival colonization increased with DW SCL use (P < 0.001), although this increase occurred for nonpathogenic species only. Fewer potential pathogens were isolated from DW SCL than from EW SCL users (P < 0.05). The lid margin consistently showed greater colonization than the conjunctiva and may be a source of potential pathogens during CL wear. Hydrogel CL wear appears to modify the ocular biota. An increased number of commensal organisms were present in DW SCL use. EW SCL use altered the spectrum of organisms isolated. These alterations may suppress the normal ocular defense mechanisms and may be relevant in the pathogenesis of CL-related disease. PMID:7591092

  16. Freshwater fishes of Bontebok National Park

    Directory of Open Access Journals (Sweden)

    I.A. Russell

    2001-08-01

    Full Text Available Fish assemblages were sampled at six sites in the Breede River in the Bontebok National Park during 1999 and 2000. A total of 380 fish from 12 species was recorded. Indigenous fish collected included one freshwater species (Barbus andrewi, two catodromous species (Anguilla mossambica, Myxus capensis. and three estuarine species (Gilchris- tella aestuaria, Monodactylusfalciformis, Mugil cephalus. Four of the species recorded were aliens (Tinea tinea, Lepomis macrochirus, Micropterus salmoides, Micropterus dolomieu and two species translocated from other South African rivers (Tilapia sparrmanii, Clarias gariepinus. A further two indigenous species (Sandelia capensis, Pseudobarbus biirchelli could potentially occur within the park, though the high abundance of alien predators means that there is little chance for recolonisation from tributaries higher in the Breede River system. There is little opportunity to meaningfully conserve most indigenous freshwater fish in Bontebok National Park.

  17. Freshwater fishes of Tsitsikamma National Park

    Directory of Open Access Journals (Sweden)

    I.A. Russell

    2002-12-01

    Full Text Available This study aimed to determine the distribution and relative abundance of freshwater fishes in the Tsitsikamma National Park. Fish assemblages in six river systems were sampled in 2001, with a total of 323 fish from eight species recorded. Indigenous fish collected included four freshwater species (Pseudobarbus afer, Pseudobarbus tenuis, Sandelia capensis, Anguilla mossambica, three estuarine species (Monodactylus falciformis, Caffrogobius gilchristi, Myxus capensis, and one alien (Micropterus salmoides. One additional indigenous species (Galaxias zebratus and two aliens (Salmo trutta, Oncorhynchus mykiss could potentially occur within the park. The topography and locality of the park presents a unique opportunity to meaningfully conserve the endangered P. tenuis as well as other fish characteristic of the eastern reaches of the Cape Floristic Region. Management action is required to minimise opportunities for further establishment and spread of alien fish species and to conserve indigenous fish assemblages within the park.

  18. Freshwater aquatic plant biomass production in Florida

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, K.R.; Sutton, D.L.; Bowes, G.

    1983-01-01

    About 8% (1.2 million ha) of the total surface area of Florida is occupied by freshwater. Many of these water bodies are eutrophic. Nutrients present in these water bodies can be potentially used to culture aquatic plants as a possible feedstock for methane production. This paper summarizes the results of known research findings on biomass production potential of freshwater aquatic plants in Florida and identifies key research needs to improve the quality and quantity of biomass yields. Among floating aquatic plants, biomass yield potential was in the order of water-hyacinth > water lettuce > pennywort > salvinia > duckweed > azolla. Pennywort, duckweed, and azolla appear to perform well during the cooler months compared to other aquatic plants. Among emergent plants, biomass yield potential was in the order of southern wild rice > cattails > soft rush > bulrush. Cultural techniques, nutrient management, and environmental factors influencing the biomass yields were discussed. 68 references.

  19. Freshwater reservoir effect variability in Northern Germany

    DEFF Research Database (Denmark)

    Philippsen, Bente; Heinemeier, Jan

    2012-01-01

    The freshwater reservoir effect is a potential problem when radiocarbon dating fishbones, shells, human bones or food crusts on pottery from sites next to rivers or lakes. The reservoir age in rivers containing considerable amounts of dissolved 14C-free carbonates can be up to several thousand...... variability that can also be expected for the past. Water DIC from different seasons, and from the same season in different years, has been dated because it is the carbon source in photosynthesis and thus at the basis of the rivers’ food webs. The radiocarbon ages of underwater plants and different parts...... years and may be highly variable. For accurate radiocarbon dating of freshwater-based samples, the order of magnitude of the reservoir effect as well as the degree of variability has to be known. The initial problem in this case was the accurate dating of food crusts on pottery from the Mesolithic sites...

  20. Superhydrophobic resistance to dynamic freshwater biofouling inception.

    Science.gov (United States)

    Krishnan, K Ghokulla; Malm, Peter; Loth, Eric

    2015-01-01

    Superhydrophobic nanotextured surfaces have gained increased usage in various applications due to their non-wetting and self-cleaning abilities. The aim of this study was to investigate nanotextured surfaces with respect to their resistance to the inception of freshwater biofouling at transitional flow conditions. Several coatings were tested including industry standard polyurethane (PUR), polytetrafluoroethylene (PTFE), capstone mixed polyurethane (PUR + CAP) and nanocomposite infused polyurethane (PUR + NC). Each surface was exposed to freshwater conditions in a lake at 4 m s(-1) for a duration of 45 min. The polyurethane exhibited the greatest fouling elements, in terms of both height and number of elements, with the superhydrophobic nanocomposite based polyurethane (PUR + NC) showing very little to no fouling. A correlation between the surface characteristics and the degree of fouling inception was observed.

  1. Assessing the freshwater distribution of yellow eel

    Directory of Open Access Journals (Sweden)

    Lasne É.

    2009-04-01

    Full Text Available In the global context of the decline in wild species, modeling the distribution of populations is a crucial aspect of ecological management. This can be a major challenge, especially for species, such as the European eel, that have complex life cycles, exhibit cryptic behavior, or migrate over long distances. A review of the literature suggests that eel size data could be used to assess and analyze freshwater distribution of eel. We argue that analyses based on small yellow eels (≤ 300 mm along the longitudinal course of rivers could provide a valuable tool for population monitoring. We propose a standardized catchment recruitment index and a colonization index based on the probability of occurrence (presence/absence data using logistic models for different size classes. The model developed here provides a convenient guide for assessing yellow eel stages in freshwater areas, and should have concrete applications for management of the species.

  2. Environmental occurrence and biota concentration of phthalate esters in Epe and Lagos Lagoons, Nigeria.

    Science.gov (United States)

    Adeogun, Aina O; Ibor, Oju R; Omogbemi, Emmanuel D; Chukwuka, Azubuike V; Adegbola, Rachel A; Adewuyi, Gregory A; Arukwe, Augustine

    2015-07-01

    The high global occurrence of phthalates in different environmental matrixes has resulted in the detection of their metabolites in human urine, blood, and breast milk, indicating a widespread human exposure. In addition, the notorious endocrine disrupting effects of phthalates have shown that they mimic or antagonize the action of endogenous hormones, consequently producing adverse effects on reproduction, growth and development. Herein, we have studied the occurrence of phthalate esters (PEs) in water, sediment and biota of two lagoons (Epe and Lagos) in Nigeria. Two fish species (Tilapia guineensis, and Chrysichthys nigrodigitatus) and a crustacean (the African river prawn--Macrobrachium vollenhovenii) were analyzed for PEs levels using a HPLC method and the derived values were used for calculating bioconcentration factor (BCF), biota-sediment accumulation factor (BSAF) and phthalate pollution index (PPI) in the biota and environment. We observed that the growth and health condition of the fish species were normal with a k-factor of >1. Sediment PE levels were compared with water, at both lagoons showing concentration pattern that is characterized as DEHP = DEP > DBP. We observed that DBP was the predominant compound in T. guineensis, C. nigrodigitatus and African prawn, at both lagoons, showing organ-specific differences in bioconcentration (BCF and BSAF) patterns in the fish species. While there were no observed consistency in the pattern of PE concentration in fish organs, elevated DBP levels in different fish organs may be related to fish habitat and degradation level of phthalates. Low concentration of DEHP, compared with DBP and DEP, was measured in fish organs and whole prawn body. The BSAF values for DEHP were lowest, and highest for DBP for all species at both lagoons, and DEHP easily accumulated more in the sediment (sediment PPI = 0.28 and 0.16 for Epe and Lagos lagoon, respectively). Overall, our findings suggest a broader environmental and human

  3. Vertebrate diversity of the Jehol Biota as compared with other lagersttten

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In the last twenty years,the extraordinary discoveries of vertebrate fossils from the Jehol Biota not only have important impli-cations for studying the evolution of major Mesozoic vertebrate groups,their paleobiostratigraphy and paleoenvironmentology,but also provide critical evidence for understanding the biodiversity changes of the Early Cretaceous ecosystem.Currently,the Jehol Biota in a narrow sense(i.e.,distribution limited to western Liaoning,northern Hebei,and southeastern Inner Mongolia) comprises a vertebrate assemblage of at least 121 genera and 142 species.Among them are 13 genera and 15 species of mammals,33 genera and 39 species of birds,30 genera and 35 species of dinosaurs,17 genera and species of pterosaurs,5 genera and species of squamates,5 genera and 7 species of choristoderes,2 genera and species of turtles,8 genera and species of am-phibians,7 genera and 13 species of fishes as well as 1 genus and species of agnathan.All these known 121 genera are extinct forms,and only a small percentage of them(e.g.,agnathans,some fishes and amphibians) can be referred to extant families.The Jehol vertebrate diversity already exceeds that of the contemporaneous lagersttten such as Santana Fauna from Brazil and the Las Hoyas Fauna from Spain,and is nearly as great as that of the Jurassic Solnhofen Fauna and the Eocene Messel Fauna from Germany.Therefore,The Jehol Biota undoubtedly represents a world class lagerst?tte in terms of both fossil preservation and vertebrate diversity.The success of the Jehol vertebrate diversity had a complex biological,geological,and paleoenviron-mental background.Analysis of the habitat and diet of various vertebrate groups also indicates that the habitat and dietary dif-ferentiation had played a key role in the success of the taxonomic diversity of vertebrates of various ranks.Furthermore,the interactions among vertebrates,plants,and invertebrates as well as the competitions among various vertebrate groups and some key

  4. Identification of Martian biota using their radioresistance ability and specific isotopic composition

    Science.gov (United States)

    Pavlov, A. K.; Kalinin, V.; Konstantinov, A.; Shelegedin, V.; Pavlov, A. A.

    2003-04-01

    Because of a thin atmosphere and weak magnetic field, Martian surface is a subject to high levels of ionizing radiation. On the other hand, variations in Martian obliquity produce the global climate oscillations (with the main period ~120000 years) of the great magnitude. Martian biota would accumulate large radiation dosage during the periods of cold climate, when it would be in the dormant state and would rebuild its population during the periods of warm climate. Therefore, all types of hypothetical Martian microorganisms living in subsurface layers of soil have to posses very high radiation tolerance. In our experiments, we find that "ordinary" bacteria (Escherichia coli and two species of Bacillus ) can develop radioresistance ability after a number of cycles of exposure to the high (almost lethal) radiation dosages, followed by recovery of the bacterial population. We show that natural cycles of this kind could take place only on Mars. On the other hand, high radiation tolerance is hardly necessary for the survival in any natural environment on Earth. A few number of terrestrial microorganisms (radioresistant bacteria) posses this peculiar ability (Deinococus radiodurance , Rubrobacter radiotolerance, Rubrobacter xylanophilus ). The radiation background on Earth, including vicinity of natural nuclear reactor Oklo is many orders of magnitude lower than the lethal dose for these microorganisms. We show that such radioresistance can be "trained" only in the Martian conditions. Therefore, we propose that Earth has been infected several times by the Martian biota on Martian meteorites. We propose that high radioresistance could be a strong sign of the Martian origin for potential microorganisms acquired in the sample return missions. Another way to identify "Martian" microorganisms and exclude contamination in returned samples involves analysis of the radionuclides abundance (being produced by the high energy cosmic rays in the Martian soil). We show that these

  5. Salmonid & freshwater Fisheries statistics England & Wales 1996

    OpenAIRE

    1997-01-01

    This is the Salmonid & Freshwater Fisheries Statistics for England & Wales 1996 produced by the Environment Agency in 1997. The principal aim of the Environment Agency in respect of fisheries is to maintain improve and develop fish stocks, the basic fisheries resource, in order to optimise the social and economic benefits from their sustainable exploitation. This report is the second collation of salmon and migratory trout catch statistics for England and Wales produced by the Environment Ag...

  6. Freshwater savings from marine protein consumption

    International Nuclear Information System (INIS)

    Marine fisheries provide an essential source of protein for many people around the world. Unlike alternative terrestrial sources of protein, marine fish production requires little to no freshwater inputs. Consuming marine fish protein instead of terrestrial protein therefore represents freshwater savings (equivalent to an avoided water cost) and contributes to a low water footprint diet. These water savings are realized by the producers of alternative protein sources, rather than the consumers of marine protein. This study quantifies freshwater savings from marine fish consumption around the world by estimating the water footprint of replacing marine fish with terrestrial protein based on current consumption patterns. An estimated 7 600 km3 yr−1 of water is used for human food production. Replacing marine protein with terrestrial protein would require an additional 350 km3 yr−1 of water, meaning that marine protein provides current water savings of 4.6%. The importance of these freshwater savings is highly uneven around the globe, with savings ranging from as little as 0 to as much as 50%. The largest savings as a per cent of current water footprints occur in Asia, Oceania, and several coastal African nations. The greatest national water savings from marine fish protein occur in Southeast Asia and the United States. As the human population increases, future water savings from marine fish consumption will be increasingly important to food and water security and depend on sustainable harvest of capture fisheries and low water footprint growth of marine aquaculture. (paper)

  7. Freshwater peat on the continental shelf

    Science.gov (United States)

    Emery, K.O.; Wigley, R.L.; Bartlett, A.S.; Rubin, M.; Barghoorn, E.S.

    1967-01-01

    Freshwater peats from the continental shelf off northeastern United States contain the same general pollen sequence as peats from ponds that are above sea level and that are of comparable radiocarbon ages. These peats indicate that during glacial times of low sea level terrestrial vegetation covered the region that is now the continental shelf in an unbroken extension from the adjacent land areas to the north and west.

  8. Pesticides in Brazilian freshwaters: a critical review.

    Science.gov (United States)

    Albuquerque, A F; Ribeiro, J S; Kummrow, F; Nogueira, A J A; Montagner, C C; Umbuzeiro, G A

    2016-07-13

    The widespread use of pesticides in agriculture can lead to water contamination and cause adverse effects on non-target organisms. Brazil has been the world's top pesticide market consumer since 2008, with 381 approved pesticides for crop use. This study provides a comprehensive literature review on the occurrence of pesticide residues in Brazilian freshwaters. We searched for information in official agency records and peer-reviewed scientific literature. Risk quotients were calculated to assess the potential risk posed to aquatic life by the individual pesticides based on their levels of water contamination. Studies about the occurrence of pesticides in freshwaters in Brazil are scarce and concentrated in few sampling sites in 5 of the 27 states. Herbicides (21) accounted for the majority of the substances investigated, followed by fungicides (11), insecticides (10) and plant growth regulators (1). Insecticides are the class of major concern. Brazil would benefit from the implementation of a nationwide pesticide freshwater monitoring program to support preventive, remediation and enforcement actions.

  9. THE DEVELOPMENT OF FRESHWATER FISHING IN ELAZIĞ

    Directory of Open Access Journals (Sweden)

    Zeki BOYRAZ

    2015-04-01

    Full Text Available Increasing world population has more demand for healthy food day after day. Our research draws attention to increasing freshwater fishery in Elazığ that increased its importance depending on the fishery activities in inland water in recent years. Our reasearch area, Elazığ, is situated in the Upper Fırat part, in the southwest of Eastern Anatolia Region. The main factor that allows freshwater fishery develop in the research field is the existence of fresh water. The most important river within the city borders is Fırat and its tributaries. Hazar Lake has a 86 km2 surface area and it is 30 km far from the city center. Also the Keban Dam, 675 km2 and Karakaya Dam, 268 km2 make up the city borders. Other important dams like Kralkızı, 57 km2 and Özlüce 26 km2 are situated in near distances. In this study we will focus on the potential and development of the freshwater fishery in Elazığ.

  10. Extraction of Freshwater and Energy from Atmosphere

    CERN Document Server

    Bolonkin, Alexander

    2007-01-01

    Author offers and researches a new, cheap method for the extraction of freshwater from the Earth atmosphere. The suggected method is fundamentally dictinct from all existing methods that extract freshwater from air. All other industrial methods extract water from a saline water source (in most cases from seawater). This new method may be used at any point in the Earth except Polar Zones. It does not require long-distance freshwater transportation. If seawater is not utilized for increasing its productivity, this inexpensive new method is very environment-friendly. The author method has two working versions: (1) the first variant the warm (hot) atmospheric air is lifted by the inflatable tube in a high altitude and atmospheric steam is condenced into freswater: (2) in the second version, the warm air is pumped 20-30 meters under the sea-surface. In the first version, wind and solar heating of air are used for causing air flow. In version (2) wind and propeller are used for causing air movment. The first method...

  11. Pesticides in Brazilian freshwaters: a critical review.

    Science.gov (United States)

    Albuquerque, A F; Ribeiro, J S; Kummrow, F; Nogueira, A J A; Montagner, C C; Umbuzeiro, G A

    2016-07-13

    The widespread use of pesticides in agriculture can lead to water contamination and cause adverse effects on non-target organisms. Brazil has been the world's top pesticide market consumer since 2008, with 381 approved pesticides for crop use. This study provides a comprehensive literature review on the occurrence of pesticide residues in Brazilian freshwaters. We searched for information in official agency records and peer-reviewed scientific literature. Risk quotients were calculated to assess the potential risk posed to aquatic life by the individual pesticides based on their levels of water contamination. Studies about the occurrence of pesticides in freshwaters in Brazil are scarce and concentrated in few sampling sites in 5 of the 27 states. Herbicides (21) accounted for the majority of the substances investigated, followed by fungicides (11), insecticides (10) and plant growth regulators (1). Insecticides are the class of major concern. Brazil would benefit from the implementation of a nationwide pesticide freshwater monitoring program to support preventive, remediation and enforcement actions. PMID:27367607

  12. Abiotic causes of the great mass extinction of marine biota at the Triassic-Jurassic boundary

    Science.gov (United States)

    Barash, M. S.

    2015-05-01

    In the interval of the Triassic-Jurassic boundary up to 80% of marine species became extinct. The main hypotheses on the causes of this mass extinction are reviewed. The extinction was triggered by a powerful eruption of basalts in the Central Atlantic Magmatic Province. In addition, several impact craters have been found. Extraterrestrial factors resulted in two main sequences of events: terrestrial, leading to strong volcanism, and extraterrestrial (impact events). They produced similar effects: emissions of harmful chemical compounds and aerosols. Consequences included the greenhouse effect, darkening of the atmosphere (which prevented photosynthesis), stagnation of the oceans, and anoxia. Biological productivity decreased; food chains collapsed. As a result, all vital processes were disturbed, and a large portion of the biota went extinct.

  13. [A new approach to modeling the diversity dynamics of Phanerozoic marine biota].

    Science.gov (United States)

    Markov, A V

    2001-01-01

    Modeling of fossil diversity dynamics is usually done with the help of the models borrowed from the population dynamics theory. However there are principal differences between organisms and taxa, reproduction and divergence, mortality and extinction that make this approach doubtful. Another model is presented here, in which absolute origination rate does not depend on diversity, the ability of new genera to sustain unpredictable environmental changes increases three times abruptly at Cambrian/Ordovician, Permian/Triassic and Cretaceous/Tertiary boundaries. In this model the diversity increases due to accumulation of long-lived genera. The computer simulation showed that the model agrees with empirical data by 15 major criteria. The laws of community evolution apparently can explain the general pattern of punctuated equilibrium in the evolution of marine biota. PMID:11871265

  14. Floodplain data: ecosystem characteristics and /sup 137/Cs concentrations in biota and soil. [ORNL

    Energy Technology Data Exchange (ETDEWEB)

    Van Voris, P.; Dahlman, R.C.

    1976-11-01

    Radiocesium (/sup 137/Cs) distribution was determined in soil, roots, ground vegetation, overstory, litter, mammals, feces, and insects for a floodplain ecosystem contaminated by radioactive wastes from Manhattan Project operations in 1944. The 2-ha research site was located on the ERDA reservation, Oak Ridge, Tennessee, in a drained holding pond between Oak Ridge National Laboratory and White Oak Lake. Maximum /sup 137/Cs concentrations in soil occurred near the old retention pond dam (84,400 pCi/g) and at the upper portion of the floodplain boundary (70,500 pCi/g). This bimodal distribution pattern of /sup 137/Cs was evident for all samples collected. Large amounts of data have been collected since the summer of 1974. This report documents the data on ecosystem characteristics and /sup 137/Cs concentrations in biota and soil.

  15. ANAEROBIC DIGESTION OF ANIMAL MANURE – IMPLICATIONS FOR CROP YIELDS AND SOIL BIOTA IN ORGANIC FARMING

    DEFF Research Database (Denmark)

    Johansen, Anders; Pommeresche, Reidun; Riely, Hugh;

    2015-01-01

    organic matter levels over the first 2 years. Application of high levels of manure increased the mortality of both surface-dwelling and soil-living earthworms just after application, but the long-term effect of manure application seemed more positive, especially at low application levels. Springtails...... negatively due to substrate shortage. Our knowledge on these processes and their influence on soil quality is scarce. Hence, a field experiment with two organic cropping systems (grass-clover ley and arable system; at two slurry-application levels) was established in 2011, to study how application......Anaerobic digestion of farmyard manures may help farmers to produce bioenergy instead of using fossil fuels, support cycling of nutrients and reduce greenhouse gas emission. However, compared to pristine slurry, digested slurry has a reduced content of organic carbon which may impact the soil biota...

  16. Pesticide Interactions with N source and Tillage: Effects on soil biota and ecosystem services

    DEFF Research Database (Denmark)

    Jensen, John; Petersen, Søren O; Elsgaard, Lars;

    . This study was planned to evaluate interactions between pesticide use and other soil management factors. The study was carried out within a long-term tillage experiment using two tillage practices (no-till (NT) and mouldboard ploughing (MP), two contrasting N sources (manure and mineral fertiliser), and two......Pesticide effects on soil biota must be interpreted in the context of the specific management practice, including rotation, fertilization, tillage, and pest control. Tillage, foe example, has been shown to reduce earthworm populations by up to 80%, depending on timing and specific tillage technique....... Such disturbances may fully or partly obscure the effects of pesticides. The direct effects of pesticides and other management factors and their interactions must, therefore, be quantified before integrated pest management strategies that protect soil biodiversity and maintain soil functions can be identified...

  17. Sensing of Scent, Fragrance, Smell, and Odor Emissions from Biota Sources

    Directory of Open Access Journals (Sweden)

    Ki-Hyun Kim

    2014-04-01

    Full Text Available People encounter enormous numbers of chemicals present in the outdoor atmosphere and/or in the various facilities they use daily. Despite such diversity, not many of them have necessarily the potential to draw human’s nasal attraction if their perception thresholds are in general not sufficiently low enough, regardless of abundance. In this sense, many types of scents, musks, fragrances, smells, odors, and pheromones are unique enough to draw a great deal of attention mainly by their presence at or near threshold levels which are far lower than those of common chemicals with poor odorant characteristics. It is known that most of the diverse characters of odor-related ingredients or expressions are commonly produced from various biota sources present in the biosphere, e.g., fauna, flora, bacteria, fruits, flowers, trees, meats, fresh/decaying foods, etc.

  18. Isolation of microplastics in biota-rich seawater samples and marine organisms

    Science.gov (United States)

    Cole, Matthew; Webb, Hannah; Lindeque, Pennie K.; Fileman, Elaine S.; Halsband, Claudia; Galloway, Tamara S.

    2014-03-01

    Microplastic litter is a pervasive pollutant present in aquatic systems across the globe. A range of marine organisms have the capacity to ingest microplastics, resulting in adverse health effects. Developing methods to accurately quantify microplastics in productive marine waters, and those internalized by marine organisms, is of growing importance. Here we investigate the efficacy of using acid, alkaline and enzymatic digestion techniques in mineralizing biological material from marine surface trawls to reveal any microplastics present. Our optimized enzymatic protocol can digest >97% (by weight) of the material present in plankton-rich seawater samples without destroying any microplastic debris present. In applying the method to replicate marine samples from the western English Channel, we identified 0.27 microplastics m-3. The protocol was further used to extract microplastics ingested by marine zooplankton under laboratory conditions. Our findings illustrate that enzymatic digestion can aid the detection of microplastic debris within seawater samples and marine biota.

  19. Floodplain data: ecosystem characteristics and 137Cs concentrations in biota and soil

    International Nuclear Information System (INIS)

    Radiocesium (137Cs) distribution was determined in soil, roots, ground vegetation, overstory, litter, mammals, feces, and insects for a floodplain ecosystem contaminated by radioactive wastes from Manhattan Project operations in 1944. The 2-ha research site was located on the ERDA reservation, Oak Ridge, Tennessee, in a drained holding pond between Oak Ridge National Laboratory and White Oak Lake. Maximum 137Cs concentrations in soil occurred near the old retention pond dam (84,400 pCi/g) and at the upper portion of the floodplain boundary (70,500 pCi/g). This bimodal distribution pattern of 137Cs was evident for all samples collected. Large amounts of data have been collected since the summer of 1974. This report documents the data on ecosystem characteristics and 137Cs concentrations in biota and soil

  20. Assessment of radiation impact on biota as a result of hypothetical accidents at small NPP

    International Nuclear Information System (INIS)

    Document available in abstract form only. Full text of publication follows: Breakthrough in the development of science and technology, caused by the creation of nuclear weapons, allowed expanding the scope of application of the energy of nuclear fission. Nuclear power plants, nuclear power installations for submarines and ships were created. The main factor of the competitiveness of nuclear energy is its success in areas of its industrial, scientific, technical application. Nuclear energy, as well as any other modern sophisticated technology used by people, is associated with a particular risk for the individuals, society and the environment. According to the classification adopted by the IAEA, small reactors are reactors with an equivalent electric power of <300 MW(e) and medium-sized reactors are reactors with an equivalent electric power of 300-700 MW(e). Russia has a unique experience in the creation and operation of reactor systems with lead-bismuth coolant for nuclear-powered submarines. Such is single unit nuclear power station with an experiment industrial power reactor installation with lead-bismuth coolant with an electric capacity of 100 MW (SVBR-100). The launch of the first power unit with the SVBR-100 is going to start up after 2017 in the city of Dimitrovgrad, Russia. After the Chernobyl and Fukushima accidents, the world community makes high demands to operation safety during running of NPPs. Due to this, the analysis of the consequences of non-routine and accidental events is the essential point of rationale for innovative nuclear technologies. In this regard, the evolution of modern radiation protection system considering the radiation protection of not only the population, but also non-human biota, cannot be disregarded. The aim of the current research was the assessment of radiological impact on biota caused by hypothetical accidents at NPP with lead-bismuth cooled small fast reactor SVBR-100. (authors)

  1. Vegetative community control of freshwater availability: Phoenix Islands case study

    Science.gov (United States)

    Engels, M.; Heinse, R.

    2014-12-01

    On small low islands with limited freshwater resources, terrestrial plant communities play a large role in moderating freshwater availability. Freshwater demands of vegetative communities are variable depending on the composition of the community. Hence, changes to community structure from production crop introductions, non-native species invasions, and climate change, may have significant implications for freshwater availability. Understanding how vegetative community changes impact freshwater availability will allow for better management and forecasting of limited freshwater supplies. To better understand these dynamics, we investigated three small tropical atolls in the Phoenix Island Protected Area, Kiribati. Despite their close proximity, these islands receive varying amounts of rainfall, are host to different plant communities and two of the islands have abandoned coconut plantations. Using electromagnetic induction, ground penetrating radar, soil samples, climate and satellite data, we present preliminary estimates of vegetative water demand for different tropical plant communities.

  2. Interactions with soil biota shift from negative to positive when a tree species is moved outside its native range.

    Science.gov (United States)

    Gundale, Michael J; Kardol, Paul; Nilsson, Marie-Charlotte; Nilsson, Urban; Lucas, Richard W; Wardle, David A

    2014-04-01

    Studies evaluating plant-soil biota interactions in both native and introduced plant ranges are rare, and thus far have lacked robust experimental designs to account for several potential confounding factors. Here, we investigated the effects of soil biota on growth of Pinus contorta, which has been introduced from Canada to Sweden. Using Swedish and Canadian soils, we conducted two glasshouse experiments. The first experiment utilized unsterilized soil from each country, with a full-factorial cross of soil origin, tree provenance, and fertilizer addition. The second experiment utilized gamma-irradiated sterile soil from each country, with a full-factorial cross of soil origin, soil biota inoculation treatments, tree provenance, and fertilizer addition. The first experiment showed higher seedling growth on Swedish soil relative to Canadian soil. The second experiment showed this effect was due to differences in soil biotic communities between the two countries, and occurred independently of all other experimental factors. Our results provide strong evidence that plant interactions with soil biota can shift from negative to positive following introduction to a new region, and are relevant for understanding the success of some exotic forest plantations, and invasive and range-expanding native species. PMID:24444123

  3. Description of Ethical Bio-Technology Assessment Tools for Agriculture and Food Production. Interim Report Ethical Bio-TA Tools

    NARCIS (Netherlands)

    Beekman, V.

    2004-01-01

    The objective of 'Ethical Bio-TA Tools' project is to develop and improve tools for the ethical assessment of new technologies in agriculture and food production in general and modern biotechnologies in particular. The developed tools need to be designed for various purposes and contexts. They shoul

  4. Interactions with soil biota shift from negative to positive when a tree species is moved outside its native range.

    Science.gov (United States)

    Gundale, Michael J; Kardol, Paul; Nilsson, Marie-Charlotte; Nilsson, Urban; Lucas, Richard W; Wardle, David A

    2014-04-01

    Studies evaluating plant-soil biota interactions in both native and introduced plant ranges are rare, and thus far have lacked robust experimental designs to account for several potential confounding factors. Here, we investigated the effects of soil biota on growth of Pinus contorta, which has been introduced from Canada to Sweden. Using Swedish and Canadian soils, we conducted two glasshouse experiments. The first experiment utilized unsterilized soil from each country, with a full-factorial cross of soil origin, tree provenance, and fertilizer addition. The second experiment utilized gamma-irradiated sterile soil from each country, with a full-factorial cross of soil origin, soil biota inoculation treatments, tree provenance, and fertilizer addition. The first experiment showed higher seedling growth on Swedish soil relative to Canadian soil. The second experiment showed this effect was due to differences in soil biotic communities between the two countries, and occurred independently of all other experimental factors. Our results provide strong evidence that plant interactions with soil biota can shift from negative to positive following introduction to a new region, and are relevant for understanding the success of some exotic forest plantations, and invasive and range-expanding native species.

  5. Interactions between above- and belowground biota: importance for small-scale vegetation mosaics in a grassland ecosystem

    NARCIS (Netherlands)

    Blomqvist, M.M.; Olff, H.; Blaauw, M.B.; Bongers, T.; Van der Putten, W.H.

    2000-01-01

    Grasslands are often characterised by small-scale mosaics in plant community composition that contribute to their diversity. Although above- and belowground biota can both cause such mosaics, few studies have addressed their interacting effects. We studied multi-trophic interactions between abovegro

  6. Phosphorus accumulation and eutrophication in feed-supply freshwater fishponds

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ming-kui; FANG Li-ping

    2006-01-01

    The rapid growth and intensification of freshwater fishery can cause imbalances between phosphorus (P) input in feed and its output in produce. This aquaculture can result in enriching exogenous P in fishponds and, consequently, accelerates the process of eutrophication. To assess relations among input, accumulation, release of P and as a consequence degrading water quality in terms of chlorophyll-a (Chl-a) in freshwater fishponds, fourteen fishponds with feed supply, nine fishponds without feed supply, and five nonfish ponds in Shaoxing Plain, southeast China were selected for comparing P accumulation in their waters and surface sediments.Surface sediment samples were collected from each pond to evaluate their total P, water soluble P, Olsen P, algal available P, and P fractions. Water samples were also collected from the ponds to measure concentrations of dissolved P and Chl-a. Total P in the sediments ranged from 0.88 to 1.73 g/kg in the fishponds with feed supply, that in the non-fish ponds ranged from 0.47 to 0.86 g/kg.Organic P, accounted for 23% to 60% of total P in the sediments, was an important P fraction and increased linearly with increasing organic matter. Long-term application of feeds resulted in increased P availability in the bottom sediments and degradation of water quality in the freshwater fishponds. Compared with non-fish ponds, sediments from the feed-supplied fishponds contained considerably higher Olsen P, algal available P, and water soluble P. Higher proportions of the labile P (NH4Cl-P) and potentially labile P (NaOH-IP) were also found in the sediments from the fishponds. High solubility of P in the sediments resulted in elevation of P and chlorophyl1-a concentration in the pond water. The dissolved P concentration in the pond water increased in the order of non-fish ponds (12 μg/L) < fishponds without feed supply (24 μg/L) < fishponds with feed supply (66 μg/L). Linear correlations between concentrations of total P, Olsen

  7. The Earliest Fossil Evidence for Life on Land and the Freshwater Origin of Algae?

    Science.gov (United States)

    Battison, L.; Brasier, M. D.; Antcliffe, J. B.

    2009-04-01

    lagerstatte. Delicate cellular structures, and even sub-cellular structures, can be preserved with high fidelity in the phosphate. These cells show evidence for life cycles that ranged from resting cysts - sometimes sculptured - to colonial vegetative stages and thence to single celled dispersal stages. Cyanobacteria, eukaryotic protists and algae are all present. The ecological structure and responses of these Torridon lake communities can be compared with those of modern, mainly acidiphilic, lakes. Together with sedimentary structures and wrinkle mats of demonstrably microbial origin, we can point to the variable development of seasonal eutrophication and stagnation in the photic zone of these ancient lakes. Population statistics of the various morphotypes reveal differences between the assemblages collected from older and younger units of the Torridon Group, attributable to differing lacustrine ecologies. Such exceptional preservation in the Proterozoic is part of an emerging picture of evolving taphonomic styles through time, in which better preservation of cells is found as we go further back into the fossil record. We attribute this remarkable preservation in the Proterozoic to very early diagenesis in a world before the evolution of a sediment Mixed Layer during the Cambrian explosion of the Metazoa. This evidence suggests that Earth's terrestrial biota and its associated phosphorus cycle were well established on land by ~1000 Ma ago. It also suggests that many algal groups, which today are obligate freshwater denizens, may have originated in freshwater lakes over a billion years ago.

  8. A computerized image database for freshwater algae recorded in Turkey

    OpenAIRE

    Şen, Bülent; SÖNMEZ, Feray; ÇETİN, Ahmet Kadri; ALP, Mehmet Tahir; ÖZER, Tülay BAYKAL

    2015-01-01

    A computer-based image database for freshwater algae recorded in Turkey has been established. A separate page was prepared for each algal taxon and each page includes images and taxonomic and ecological information related to the taxon. Algal images were obtained mainly from authors of algal studies previously carried out in various freshwater bodies in Turkey. Data were then standardized in accordance with that of the central database of Turkish herbaria and a database for Turkish freshwater...

  9. Implications of dam obstruction for global freshwater fish diversity

    OpenAIRE

    Reidy Liermann, Catherine; Nilsson, Christer; Robertson, James; Ng, Rebecca

    2012-01-01

    Dams are obstructing rivers worldwide, impairing habitat and migration opportunities for many freshwater fish species; however, global data linking dam and fish distributions have been limited. Here, we quantify dam obstruction at the biogeographic scale of freshwater ecoregion, which provides the spatial framework necessary to assess the risk of fish species loss due to dams and allows us to identify both ecoregions and genera at risk. Nearly 50% of the 397 assessed freshwater ecoregions are...

  10. Restricted-Range Fishes and the Conservation of Brazilian Freshwaters

    OpenAIRE

    Cristiano Nogueira; Paulo A. Buckup; Menezes, Naercio A.; Osvaldo T. Oyakawa; Thais P Kasecker; Ramos Neto, Mario B.; da Silva, José Maria C.

    2010-01-01

    BACKGROUND: Freshwaters are the most threatened ecosystems on earth. Although recent assessments provide data on global priority regions for freshwater conservation, local scale priorities remain unknown. Refining the scale of global biodiversity assessments (both at terrestrial and freshwater realms) and translating these into conservation priorities on the ground remains a major challenge to biodiversity science, and depends directly on species occurrence data of high taxonomic and geograph...

  11. Tropical versus high latitude freshwater influence on the Atlantic circulation

    OpenAIRE

    Goelzer, H.; J. Mignot; Levermann, A; Rahmstorf, S.

    2006-01-01

    We investigate the model sensitivity of the Atlantic meridional overturning circulation (AMOC) to anomalous freshwater flux in the tropical and northern Atlantic. Forcing in both locations leads to the same qualitative response: a positive freshwater anomaly induces a weakening of the AMOC and a negative freshwater anomaly strengthens the AMOC. Strong differences arise in the temporal characteristics and amplitude of the response. The advection of the tropical anomaly up to the deep water for...

  12. Freshwater Ecosystem Conservation: Towards a Comprehensive Water Resources Management Strategy

    OpenAIRE

    Enrique Bucher; Gonzalo Castro; Vinio Floris

    1997-01-01

    Conservation of freshwater biodiversity has been seriously neglected throughout the world, and entire ecosystems are threatened with extinction. Unfortunately, freshwater sustainability issues do not appear to be a primary consideration in the planning and implementation of water use projects, nor in the allocation of use permits. This paper discusses the value and function of Latin American freshwater ecosystems and gives a comprehensive approach to developing a sustainable water resources m...

  13. Po-210 and other radionuclides in terrestrial and freshwater environments

    International Nuclear Information System (INIS)

    This report provides new information on Po-210 (and where appropriate its grandparent Pb-210) behaviour in environmental systems including humans. This has primarily been achieved through measurements of Po-210 in aquatic and terrestrial environments that has led to the derivation of information on the levels of this radioisotope in plants, animals and the biotic components of their habitat (i.e. water, soil) providing basic information on transfer where practicable. For freshwater environments, Po-210 concentration ratios derived for freshwater benthic fish and bivalve mollusc were substantially different to values collated from earlier review work. For terrestrial environments, activity concentrations of Po-210 in small mammals (although of a preliminary nature because no correction was made for ingrowth from Pb-210) were considerably higher than values derived from earlier data compilations. It was envisaged that data on levels of naturally occurring radionuclides would render underpinning data sets more comprehensive and would thus allow more robust background dose calculations to be performed subsequently. By way of example, unweighted background dose-rates arising from internal distributions of Po-210 were calculated for small mammals in the terrestrial study. The biokinetics of polonium in humans has been studied following chronic and acute oral intakes of selected Po radioisotopes. This work has provided information on gastrointestinal absorption factors and biological retention times thus improving the database upon which committed effective doses to humans are derived. The information generated in the report, in its entirety, should be of direct relevance for both human and non-human impact assessments. (au)

  14. Po-210 and other radionuclides in terrestrial and freshwater environments

    Energy Technology Data Exchange (ETDEWEB)

    Gjelsvik, Runhild; Brown, Justin (eds.) (Norwegian Radiation Protection Authority (Norway)); Holm, Elis (Univ. of Lund (Sweden)); Roos, Per (Risoe DTU (Denmark)); Saxen, Ritva; Outola, Iisa (STUK - Radiation and Nuclear Safety Authority (Finland))

    2009-01-15

    This report provides new information on Po-210 (and where appropriate its grandparent Pb-210) behaviour in environmental systems including humans. This has primarily been achieved through measurements of Po-210 in aquatic and terrestrial environments that has led to the derivation of information on the levels of this radioisotope in plants, animals and the biotic components of their habitat (i.e. water, soil) providing basic information on transfer where practicable. For freshwater environments, Po-210 concentration ratios derived for freshwater benthic fish and bivalve mollusc were substantially different to values collated from earlier review work. For terrestrial environments, activity concentrations of Po-210 in small mammals (although of a preliminary nature because no correction was made for ingrowth from Pb-210) were considerably higher than values derived from earlier data compilations. It was envisaged that data on levels of naturally occurring radionuclides would render underpinning data sets more comprehensive and would thus allow more robust background dose calculations to be performed subsequently. By way of example, unweighted background dose-rates arising from internal distributions of Po-210 were calculated for small mammals in the terrestrial study. The biokinetics of polonium in humans has been studied following chronic and acute oral intakes of selected Po radioisotopes. This work has provided information on gastrointestinal absorption factors and biological retention times thus improving the database upon which committed effective doses to humans are derived. The information generated in the report, in its entirety, should be of direct relevance for both human and non-human impact assessments. (au)

  15. General Relationships between Abiotic Soil Properties and Soil Biota across Spatial Scales and Different Land-Use Types

    Science.gov (United States)

    Birkhofer, Klaus; Schöning, Ingo; Alt, Fabian; Herold, Nadine; Klarner, Bernhard; Maraun, Mark; Marhan, Sven; Oelmann, Yvonne; Wubet, Tesfaye; Yurkov, Andrey; Begerow, Dominik; Berner, Doreen; Buscot, François; Daniel, Rolf; Diekötter, Tim; Ehnes, Roswitha B.; Erdmann, Georgia; Fischer, Christiane; Foesel, Bärbel; Groh, Janine; Gutknecht, Jessica; Kandeler, Ellen; Lang, Christa; Lohaus, Gertrud; Meyer, Annabel; Nacke, Heiko; Näther, Astrid; Overmann, Jörg; Polle, Andrea; Pollierer, Melanie M.; Scheu, Stefan; Schloter, Michael; Schulze, Ernst-Detlef; Schulze, Waltraud; Weinert, Jan; Weisser, Wolfgang W.; Wolters, Volkmar; Schrumpf, Marion

    2012-01-01

    Very few principles have been unraveled that explain the relationship between soil properties and soil biota across large spatial scales and different land-use types. Here, we seek these general relationships using data from 52 differently managed grassland and forest soils in three study regions spanning a latitudinal gradient in Germany. We hypothesize that, after extraction of variation that is explained by location and land-use type, soil properties still explain significant proportions of variation in the abundance and diversity of soil biota. If the relationships between predictors and soil organisms were analyzed individually for each predictor group, soil properties explained the highest amount of variation in soil biota abundance and diversity, followed by land-use type and sampling location. After extraction of variation that originated from location or land-use, abiotic soil properties explained significant amounts of variation in fungal, meso- and macrofauna, but not in yeast or bacterial biomass or diversity. Nitrate or nitrogen concentration and fungal biomass were positively related, but nitrate concentration was negatively related to the abundances of Collembola and mites and to the myriapod species richness across a range of forest and grassland soils. The species richness of earthworms was positively correlated with clay content of soils independent of sample location and land-use type. Our study indicates that after accounting for heterogeneity resulting from large scale differences among sampling locations and land-use types, soil properties still explain significant proportions of variation in fungal and soil fauna abundance or diversity. However, soil biota was also related to processes that act at larger spatial scales and bacteria or soil yeasts only showed weak relationships to soil properties. We therefore argue that more general relationships between soil properties and soil biota can only be derived from future studies that consider

  16. General relationships between abiotic soil properties and soil biota across spatial scales and different land-use types.

    Directory of Open Access Journals (Sweden)

    Klaus Birkhofer

    Full Text Available Very few principles have been unraveled that explain the relationship between soil properties and soil biota across large spatial scales and different land-use types. Here, we seek these general relationships using data from 52 differently managed grassland and forest soils in three study regions spanning a latitudinal gradient in Germany. We hypothesize that, after extraction of variation that is explained by location and land-use type, soil properties still explain significant proportions of variation in the abundance and diversity of soil biota. If the relationships between predictors and soil organisms were analyzed individually for each predictor group, soil properties explained the highest amount of variation in soil biota abundance and diversity, followed by land-use type and sampling location. After extraction of variation that originated from location or land-use, abiotic soil properties explained significant amounts of variation in fungal, meso- and macrofauna, but not in yeast or bacterial biomass or diversity. Nitrate or nitrogen concentration and fungal biomass were positively related, but nitrate concentration was negatively related to the abundances of Collembola and mites and to the myriapod species richness across a range of forest and grassland soils. The species richness of earthworms was positively correlated with clay content of soils independent of sample location and land-use type. Our study indicates that after accounting for heterogeneity resulting from large scale differences among sampling locations and land-use types, soil properties still explain significant proportions of variation in fungal and soil fauna abundance or diversity. However, soil biota was also related to processes that act at larger spatial scales and bacteria or soil yeasts only showed weak relationships to soil properties. We therefore argue that more general relationships between soil properties and soil biota can only be derived from future

  17. Toxicological Benchmarks for Screening Potential Contaminants of Concern for Effects on Sediment-Associated Biota

    Energy Technology Data Exchange (ETDEWEB)

    Hull, R.N.

    1993-01-01

    A hazardous waste site may contain hundreds of chemicals; therefore, it is important to screen contaminants of potential concern for the ecological risk assessment. Often this screening is done as part of a screening assessment, the purpose of which is to evaluate the available data, identify data gaps, and screen contaminants of potential concern. Screening may be accomplished by using a set of toxicological benchmarks. These benchmarks are helpful in determining whether contaminants warrant further assessment or are at a level that requires no further attention. If a chemical concentration or the reported detection limit exceeds a proposed lower benchmark, further analysis is needed to determine the hazards posed by that chemical. If, however, the chemical concentration falls below the lower benchmark value, the chemical may be eliminated from further study. The use of multiple benchmarks is recommended for screening chemicals of concern in sediments. Integrative benchmarks developed for the National Oceanic and Atmospheric Administration and the Florida Department of Environmental Protection are included for inorganic and organic chemicals. Equilibrium partitioning benchmarks are included for screening nonionic organic chemicals. Freshwater sediment effect concentrations developed as part of the U.S. Environmental Protection Agency's (EPA's) Assessment and Remediation of Contaminated Sediment Project are included for inorganic and organic chemicals (EPA 1996). Field survey benchmarks developed for the Ontario Ministry of the Environment are included for inorganic and organic chemicals. In addition, EPA-proposed sediment quality criteria are included along with screening values from EPA Region IV and Ecotox Threshold values from the EPA Office of Solid Waste and Emergency Response. Pore water analysis is recommended for ionic organic compounds; comparisons are then made against water quality benchmarks. This report is an update of three prior reports

  18. Screening of perfluorinated compounds in water, sediment and biota of the Llobregat River basin (NE Spain)

    Science.gov (United States)

    Campo, Julian; Perez, Francisca; Pico, Yolanda; Farre, Marinella; Barcelo, Damia; Andreu, Vicente

    2014-05-01

    PFCs present significant thermal and chemical stability being persistent in the environment, where they can bio-accumulate and adversely affect humans and wildlife (Llorca et al., 2012). Human exposure to PFCs is of concern since PFCs tend to be associated with fatty acid binding proteins in the liver or albumin proteins in blood, and have been detected in human serum, urine, saliva, seminal plasma and breast milk (Sundstrom et al., 2011). This study is aimed at the screening of 21 perfluorinated compounds (PFCs) in environmental samples by high-performance liquid chromatography tandem mass spectrometry (LC-MS/MS). The main objective is to identify target compounds at low levels in water, sediments and biota of the Llobregat River (2010), second longest river in Catalonia and one of Barcelona's major drinking water resources. PFCs were extracted from water samples by Solid Phase Extraction (SPE); from sediment by ultrasonication with acidified methanol followed by an off-line SPE procedure (Picó et al., 2012), and from biota (fish) with alkaline digestion, clean-up by TurboFlow™ on line technology coupled to LC-MS/MS (Llorca et al., 2012). The limits of detection (LODs) and limits of quantification (LOQs) of the method were calculated by analysis of spiked river water, sediment, and biota with minimum concentrations of each individual compound at a signal-to-noise ratio of 3 and 10, respectively. The LODs and LOQs of the method in river water ranged between 0.004 and 0.8 ng L-1 and between 0.01 and 2 ng L-1, respectively. In sediment LODs were 0.013-2.667 ng g-1 dry weight (dw) and LOQs were 0.04-8 ng g-1 dw, meanwhile in biota these were 0.006-0.7 pg μL-1 and 0.02-2.26 pg μL-1, respectively. Recoveries ranged between 65% and 102% for all target compounds. The method was applied to study the spatial distribution of these compounds in the Llobregat River basin. For this, a total of 40 samples were analysed (14 water, 14 sediments, 12 fishes). Of the 21 target

  19. Freshwater flux to Sermilik Fjord, SE Greenland

    Directory of Open Access Journals (Sweden)

    S. H. Mernild

    2010-07-01

    Full Text Available Fluctuations in terrestrial surface freshwater flux to Sermilik Fjord, SE Greenland, were simulated and analyzed. SnowModel, a state-of-the-art snow-evolution, snow and ice melt, and runoff modeling system, was used to simulate the temporal and spatial terrestrial runoff distribution to the fjord based on observed meteorological data (1999–2008 from stations located on and around the Greenland Ice Sheet (GrIS. Simulated runoff was compared and verified against independent glacier catchment runoff observations (1999–2005. Modeled runoff to Sermilik Fjord was highly variable, ranging from 2.9×109 m3 y−1 in 1999 to 5.9×109 m3 y−1 in 2005. The uneven spatial runoff distribution produced an areally-averaged annual maximum runoff at the Helheim glacier terminus of more than 3.8 m w.eq. The sub-catchment runoff of the Helheim glacier region accounted for 25% of the total runoff to Sermilik Fjord. The runoff distribution from the different sub-catchments suggested a strong influence from the spatial variation in glacier coverage. To assess the Sermilik Fjord freshwater flux, simulated terrestrial runoff and net precipitation (precipitation minus evaporation and sublimation for the fjord area were combined with satellite-derived ice discharge and subglacial geothermal and frictional melting due to basal ice motion. A terrestrial freshwater flux of ~40.4×109 m3 y−1 was found for Sermilik Fjord, with an 11% contribution originated from surface runoff. For the Helheim glacier sub-catchment only 4% of the flux originated from terrestrial surface runoff.

  20. Middle Jurassic continental biota and paleolandscape in the Dubinino locality (Sharypovo area, Krasnoyarsk krai)

    Science.gov (United States)

    Ivantsov, S. V.; Bystritskaya, L. I.; Krasnolutskii, S. A.; Lyalyuk, K. P.; Frolov, A. O.; Alekseev, A. S.

    2016-09-01

    On the basis of the lithological-facies analysis, it was established that deposits of the Upper Itat Subformation, comprising the Dubinino locality of the Middle Jurassic flora and insects (Sharypovo district, Krasnoyarsk krai), accumulated in alluvial and lacustrine and, to a lesser extent, floodplain environments (floodplain and alluvial fan facies). The occurrence of remains of insects, macroremains of flora, spores, and pollen allowed us to make a paleoreconstruction of an area with a strongly dissected relief: continental fresh-water reservoir (lake) with varying degree of overflow, surrounded by hills covered with gymnospermous and ginkgo forests.

  1. Monitoring endangered freshwater biodiversity using environmental DNA

    DEFF Research Database (Denmark)

    Thomsen, Philip Francis; Kielgast, Jos; Iversen, Lars L.;

    2012-01-01

    that depend on practical and taxonomic expertise, which is rapidly declining. Here, we show that a diversity of rare and threatened freshwater animals-representing amphibians, fish, mammals, insects and crustaceans-can be detected and quantified based on DNA obtained directly from small water samples of lakes...... of amphibians and fish can be detected by high-throughput sequencing of DNA extracted from pond water. Our findings underpin the ubiquitous nature of DNA traces in the environment and establish environmental DNA as a tool for monitoring rare and threatened species across a wide range of taxonomic groups....

  2. Freshwater reservoir effect variability in Northern Germany

    DEFF Research Database (Denmark)

    Philippsen, B.; Heinemeier, J.

    2013-01-01

    The freshwater reservoir effect is a potential problem when radiocarbon dating fish bones, shells, human bones, or food crusts on pottery from sites near rivers or lakes. The reservoir age in hardwater rivers can be up to several thousand years and may be highly variable. Accurate 14C dating of f...... that can also be expected for the past. This knowledge will be applied to the dating of food crusts on pottery from the Mesolithic sites Kayhude at the Alster River and Schlamersdorf at the Trave River, both in Schleswig-Holstein, northern Germany....

  3. Trade-offs in osmoregulation and parallel shifts in molecular function follow ecological transitions to freshwater in the Alewife.

    Science.gov (United States)

    Velotta, Jonathan P; McCormick, Stephen D; Schultz, Eric T

    2015-10-01

    Adaptation to freshwater may be expected to reduce performance in seawater because these environments represent opposing selective regimes. We tested for such a trade-off in populations of the Alewife (Alosa pseudoharengus). Alewives are ancestrally anadromous, and multiple populations have been independently restricted to freshwater (landlocked). We conducted salinity challenge experiments, whereby juvenile Alewives from one anadromous and multiple landlocked populations were exposed to freshwater and seawater on acute and acclimation timescales. In response to acute salinity challenge trials, independently derived landlocked populations varied in the degree to which seawater tolerance has been lost. In laboratory-acclimation experiments, landlocked Alewives exhibited improved freshwater tolerance, which was correlated with reductions in seawater tolerance and hypo-osmotic balance, suggesting that trade-offs in osmoregulation may be associated with local adaptation to freshwater. We detected differentiation between life-history forms in the expression of an ion-uptake gene (NHE3), and in gill Na(+) /K(+) -ATPase activity. Trade-offs in osmoregulation, therefore, may be mediated by differentiation in ion-uptake and salt-secreting pathways. PMID:26374626

  4. Uptake, turnover and distribution of chlorinated fatty acids in aquatic biota

    Energy Technology Data Exchange (ETDEWEB)

    Bjoern, Helena

    1999-09-01

    Chlorinated fatty acids (CIFAs) are the major contributors of extractable, organically bound chlorine in fish lipids. A known anthropogenic source of CIFAs is chlorine bleached pulp production. Additional anthropogenic sources may exist, e.g., chlorine-containing discharge from industrial and household waste and they may also occur naturally. CIFAs have a wide geographic distribution. They have, for instance, been identified in fish both from Alaskan and Scandinavian waters. In toxicological studies of CIFAs, the most pronounced effects have been found in reproductive related processes. CIFAs have also been shown to disrupt cell membrane functions. The present study was carried out to further characterise the ecotoxicological properties of CIFAs and their presence in biota. To investigate the biological stability of CIFAs, two experiments were carried out using radiolabelled chlorinated and non-chlorinated fatty acids. In both experiments, CIFAs were taken up from food by fish and assimilated to lipids. From the first experiment it was concluded that the chlorinated fatty acid investigated was turned over in the fish to a lower degree than the non-chlorinated analogue. In the second experiment, the transfer of a chlorinated fatty acid was followed over several trophic levels and the chlorinated fatty acid was transferred to the highest trophic level. In samples with differing loads of persistent organic pollutants (POPs) from both fish and marine mammals, high concentrations and diversity of CIFAs were detected. This was also observed in samples with low POP concentration. Chlorohydroxy fatty acids made up a considerable portion of the CIFAs in certain samples, both from limnic fish and marine mammals. CIFAs in fish were found to be bound in complex lipids such as triacylglycerols (storage lipids) and phospholipids, as well as in acyl sterols (membrane lipids). In the marine mammals investigated, high concentrations of CIFAs were mainly bound in phospholipids. If

  5. Technical report: Metal concentrations in sediments, and selected biota from mine tailings in Gastineau Channel, Juneau, Alaska [Draft

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Hardrock gold mining occurred in Juneau from 1880 to 1944. Tailings and waste rock from the mines were deposited into Gastineau Channel and formed beaches along...

  6. Isolation and characterization of the microbial community of a freshwater distribution system

    International Nuclear Information System (INIS)

    This investigation provides generic information on culturable and non-culturable microbial community of a freshwater distribution system. Culture based and culture independent (16S rRNA gene sequencing) techniques were used to identify the resident microbial community of the system. Selective isolation of the fouling bacteria such as biofilm formers and corrosion causing bacteria was also attempted. Denaturing gradient gel electrophoresis (DGGE) was carried out and the bands were sequenced to obtain the diversity of the total bacterial types. Pseudomonas aeruginosa was predominantly observed in most of the samples. A variety of bacteria, related to groups such as Cyanobacteria, Proteobacteria, Actinobacteria, Bacteroidetes and Firmicutes were identified. The study highlights the relevance of the observed microbial diversity with respect to material deterioration in a freshwater distribution system, which can aid in designing effective control methods. (author)

  7. Life history traits variation in heterogeneous environment: The case of a freshwater snail resistance to pond drying

    OpenAIRE

    Chapuis, Elodie; Ferdy, Jean-Baptiste

    2012-01-01

    Ecologists and population geneticists have long suspected that the diversity of living organisms was connected to the structure of their environment. In heterogeneous environments, diversifying selection combined to restricted gene flow may indeed lead to locally adapted populations. The freshwater snail, Galba truncatula, is a good model to address this question because it is present in a heterogeneous environment composed of temporary and permanent waters. In order to test the selective imp...

  8. Freshwater fluxes through the Western Fram Strait

    Science.gov (United States)

    Meredith, Michael; Heywood, Karen; Dennis, Paul; Goldson, Laura; White, Rowan; Fahrbach, Eberhard; Schauer, Ursula; Østerhus, Svein

    Two hydrographic and δ18O transects across Fram Strait (Aug-Sept 1997, 1998) are used to examine freshwater contributions to the East Greenland Current (EGC). The EGC featured up to ˜16% meteoric water in both years, but was made comparatively more saline through the formation of up to ˜11 m of sea ice. We derive meteoric water fluxes of ˜3680 km³yr-1 in Aug-Sept 1997, and ˜2000 km³yr-1 in Aug-Sept 1998. The 1997 and 1998 data show a long-term mean sea ice flux through Fram Strait around half the long-term mean meteoric water flux. A 1991 δ18O section [Bauch et al., 1995] yielded a very similar ratio. Our 1998 section reveals fresh, low-δ18O water on the East Greenland shelf whose comparatively large volume constitutes a potentially significant contribution to the total freshwater flux through Fram Strait. Such fluxes are important to the regional and global thermohaline circulation; we suggest that efforts towards monitoring both the EGC and East Greenland shelf waters are thus required.

  9. Reclaiming freshwater sustainability in the Cadillac Desert

    Science.gov (United States)

    Sabo, John L.; Sinha, Tushar; Bowling, Laura C.; Schoups, Gerrit H.W.; Wallender, Wesley W.; Campana, Michael E.; Cherkauer, Keith A.; Fuller, Pam L.; Graf, William L.; Hopmans, Jan W.; Kominoski, John S.; Taylor, Carissa; Trimble, Stanley W.; Webb, Robert H.; Wohl, Ellen E.

    2010-01-01

    Increasing human appropriation of freshwater resources presents a tangible limit to the sustainability of cities, agriculture, and ecosystems in the western United States. Marc Reisner tackles this theme in his 1986 classic Cadillac Desert: The American West and Its Disappearing Water. Reisner's analysis paints a portrait of region-wide hydrologic dysfunction in the western United States, suggesting that the storage capacity of reservoirs will be impaired by sediment infilling, croplands will be rendered infertile by salt, and water scarcity will pit growing desert cities against agribusiness in the face of dwindling water resources. Here we evaluate these claims using the best available data and scientific tools. Our analysis provides strong scientific support for many of Reisner's claims, except the notion that reservoir storage is imminently threatened by sediment. More broadly, we estimate that the equivalent of nearly 76% of streamflow in the Cadillac Desert region is currently appropriated by humans, and this figure could rise to nearly 86% under a doubling of the region's population. Thus, Reisner's incisive journalism led him to the same conclusions as those rendered by copious data, modern scientific tools, and the application of a more genuine scientific method. We close with a prospectus for reclaiming freshwater sustainability in the Cadillac Desert, including a suite of recommendations for reducing region-wide human appropriation of streamflow to a target level of 60%.

  10. Heart Rate Sensor for Freshwater Mussels

    Science.gov (United States)

    Just, C. L.; Vial, D. P.; Kruger, A.; Niemeier, J. J.; Lee, H. W.; Schroer, H. W.

    2014-12-01

    Researchers have long been interested the cardiac activity of mollusks. First, it is important as a basic measure of the animal's metabolism. Further, activities such as feeding and burrowing affect heart rate, as do environmental factors such as water salinity, water temperature, exposure, and predation. We have developed a small, noninvasive sensor for measuring freshwater mussel heart rate. Its working principle is as follows. An infrared (IR) light-emitting diode is placed in contact with the mussel shell. Some of the IR penetrates through the shell, reflects off internal organs, and traverses back. A photodetector detects this IR, and electronics condition the signal. The heartbeat of the animal modulates the IR, allowing one to measure the heart rate. The technique is widely-used in finger heart-rate monitors in humans. The sensors do not have to be positioned above the heart and several locations on the mussel shell work well. The sensor is small (8 mm × 10 mm) and consumes less than 1 mA, and has a simple one-wire interface that allows for easy integration into data acquisition hardware. We present heart rate measurements for the common pocketbook (lampsilis cardium) freshwater mussel.

  11. Climate and local abundance in freshwater fishes.

    Science.gov (United States)

    Knouft, Jason H; Anthony, Melissa M

    2016-06-01

    Identifying factors regulating variation in numbers of individuals among populations across a species' distribution is a fundamental goal in ecology. A common prediction, often referred to as the abundant-centre hypothesis, suggests that abundance is highest near the centre of a species' range. However, because of the primary focus on the geographical position of a population, this framework provides little insight into the environmental factors regulating local abundance. While range-wide variation in population abundance associated with environmental conditions has been investigated in terrestrial species, the relationship between climate and local abundance in freshwater taxa across species' distributions is not well understood. We used GIS-based temperature and precipitation data to determine the relationships between climatic conditions and range-wide variation in local abundance for 19 species of North American freshwater fishes. Climate predicted a portion of the variation in local abundance among populations for 18 species. In addition, the relationship between climatic conditions and local abundance varied among species, which is expected as lineages partition the environment across geographical space. The influence of local habitat quality on species persistence is well documented; however, our results also indicate the importance of climate in regulating population sizes across a species geographical range, even in aquatic taxa. PMID:27429769

  12. 40 CFR 35.1605-2 - Freshwater lake.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Freshwater lake. 35.1605-2 Section 35.1605-2 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GRANTS AND OTHER FEDERAL ASSISTANCE... Lakes § 35.1605-2 Freshwater lake. Any inland pond, reservoir, impoundment, or other similar body...

  13. Recent changes in the freshwater composition east of Greenland

    NARCIS (Netherlands)

    de Steur, L.; Pickart, R.S.; Torres, D.J.; Valdimarsson, H.

    2015-01-01

    Results from three hydrographic surveys across the East Greenland Current between 2011 and 2013 are presented with focus on the freshwater sources. End-member analysis using salinity, d18O, and nutrient data shows that while meteoric water dominated the freshwater content, a significant amount of Pa

  14. Water rules all processes in tidal freshwater wetlands

    NARCIS (Netherlands)

    Barendregt, A.

    2012-01-01

    Three essential factors cause the presence of tidal freshwater wetlands (TFW). First, it is a freshwater ecosystem located in the upper part of the estuary, where permanent input of river water creates fresh conditions constantly. Second, there is a tidal pulse that causes very dynamic conditions in

  15. Character, Age and Ecology of the Hezheng Biota from Northwestern China

    Institute of Scientific and Technical Information of China (English)

    DENG Tao

    2005-01-01

    The Hezheng area of Gansu Province produces the most abundant mammal fossils in China as well as the whole Eurasia, and it also produces other Cenozoic fossils of different animals and plants. Therefore, all of them are named the Hezheng Biota. Mammals are very sensitive to environmental changes, and thus the evolution of mammalian faunas in the Hezheng area reflects the strong uplift of the Tibetan Plateau during the Late Cenozoic, which dramatically affects environmental changes. In the Hezheng area, micromammals are not very rich, but some of them still are important. It is relatively uncommon that three primates are found from the Middle Miocene and the Early Pleistocene deposits. Since the Middle Miocene, carnivores have become important components in the ecosystem of the Hezheng area, and dominated in the Early Pleistocene. The Middle Miocene is a time of high diversity for Proboscidea, characterized by shovel-tusked elephants. Perissodactyls in the Hezheng area are very abundant, especially Late Oligocene and Late Miocene rhinoceroses as well as the Late Miocene and Early Pleistocene horses. From the Middle Miocene, artiodactyls became important components of the mammalian faunas, especially bovids.

  16. Mass extinction of the marine biota at the Ordovician-Silurian transition due to environmental changes

    Science.gov (United States)

    Barash, M. S.

    2014-11-01

    The terminal Ordovician was marked by one of five great mass extinction events of the Phanerozoic (445.6-443.0 Ma ago), when up to 86% of the marine species became extinct. The rapid onset of the continental glaciation on Gondwana determined by its position in the South Pole area; the cooling; the hydrodynamic changes through the entire water column in the World Ocean; and the corresponding sea level fall, which was responsible for the reduction of shelf areas and shallow-water basins, i.e., the main ecological niche of the Ordovician marine biota, were main prerequisites of the stress conditions. Similar to other mass extinction events, these processes were accompanied by volcanism, impact events, a corresponding reduction of the photosynthesis and bioproductivity, the destruction of food chains, and anoxia. The appearance and development of terrestrial plants and microphytoplankton, which consumed atmospheric carbon dioxide, thus, diminishing the greenhouse effect and promoting the transition of the climatic system to the glacial mode, played a unique role in that period.

  17. Experimental taphonomy and the anatomy and diversity of the earliest fossil vertebrates (Chengjiang Biota, Cambrian, China)

    Science.gov (United States)

    Purnell, Mark; Gabbott, Sarah; Murdock, Duncan; Cong, Peiyun

    2016-04-01

    The oldest fossil vertebrates are from the Lower Cambrian Chengjiang biota of China, which contains four genera of fish-like, primitive vertebrates: Haikouichthys, Myllokunmingia, Zhongjianichthys and Zhongxiniscus. These fossils play key roles in calibrating molecular clocks and informing our view of the anatomy of animals close to the origin of vertebrates, potentially including transitional forms between vertebrates and their nearest relatives. Despite the evident importance of these fossils, the degree to which taphonomic processes have affected their anatomical completeness has not been investigated. For example, some or all might have been affected by stemward slippage - the pattern observed in experimental decay of non-biomineralised chordates in which preferential decay of synapomorphies and retention of plesiomorphic characters would cause fossil taxa to erroneously occupy more basal positions than they should. This hypothesis is based on experimental data derived from decay of non-biomineralised chordates under laboratory conditions. We have expanded this analysis to include a broader range of potentially significant environmental variables; we have also compared and combined the results of experiments from several taxa to identify general patterns of chordate decay. Examination of the Chengjiang vertebrates in the light of these results demonstrates that, contrary to some assertions, experimentally derived models of phylogenetic bias are applicable to fossils. Anatomical and phylogenetic interpretations of early vertebrates that do not take taphonomic biases into account risk overestimating diversity and the evolutionary significance of differences between fossil specimens.

  18. Comparison of Soil Biota Between Organic and Conventional Agroecosystems in Oregon, USA

    Institute of Scientific and Technical Information of China (English)

    WU Shan-Mei; HU Dun-Xiao; E. R. INGHAM

    2005-01-01

    Soil samples at 0-10 cm in depth were collected periodically at paired fields in Corvallis, Oregon, USA to compare differences in soil microbial and faunal populations between organic and conventional agroecosystems. Results showed that the organic soil ecosystem had a significantly higher (P < 0.05) average number or biomass of soil bacteria; densities of flagellates, amoebae of protozoa; some nematodes, such as microbivorous and predaceous nematodes and plant-parasitic nematodes; as well as Collembola. Greater numbers of Rhabditida (such as Rhabditis spp.), were present in the organic soil ecosystem while Panagrolaimus spp. were predominant in the conventional soil ecosystem. The omnivores and predators of Acarina in the Mesostigmata (such as Digamasellidae and Laelapid), and Prostigmata (such as Alicorhaiidae and Rhagidiidae), were also more abundant in the organic soil ecosystem. However, fungivorous Prostigmata (such as Terpnacaridae and Nanorchestidae) and Astigmata (such as Acarida) were significantly higher (P < 0.05) in the conventional soil ecosystem, which supported the finding that total fungal biomass was greater in the conventional soil ecosystem. Seansonal variations of the population depended mostly on soil moisture condition and food web relationship.The population declined from May to October for both agroecosystems. However, higher diversities and densities of soil biota survived occurred in the organic soil ecosystem in the dry season.

  19. Dependency of soil activity concentration on soil -biota concentration ratio of radionuclides for earthworm

    Energy Technology Data Exchange (ETDEWEB)

    Keum, Dong Kwon; Kim, Byeong Ho; Jun, In; Lim, Kwang Muk; Choi, Yong Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-05-15

    The transfer of radionuclides to wildlife (non-human biota) is normally quantified using an equilibrium concentration ratio (CR{sub eq}), defined as the radionuclide activity concentration in the whole organism (fresh weight) divided by that in the media (dry weight for soil). The present study describes the effect of soil radionuclide activity concentration on the transfer of {sup 137}Cs, {sup 85}Sr and {sup 65}Zn to a functionally important wildlife group, annelids, using a commonly studied experimental worm (E.andrei). Time-dependent whole body concentration ratios of {sup 137}Cs, {sup 85}Sr and {sup 65}Zn for the earthworm were experimentally measured for artificially contaminated soils with three different activity concentrations for each radionuclide which were considerably higher than normal background levels. Two parameters of a first order kinetic model, the equilibrium concentration ratio (CR{sub eq}) and the effective loss rate constant (k), were estimated by comparison of experimental CR results with the model prediction

  20. Contrasting food web factor and body size relationships with Hg and Se concentrations in marine biota.

    Directory of Open Access Journals (Sweden)

    Roxanne Karimi

    Full Text Available Marine fish and shellfish are primary sources of human exposure to mercury, a potentially toxic metal, and selenium, an essential element that may protect against mercury bioaccumulation and toxicity. Yet we lack a thorough understanding of Hg and Se patterns in common marine taxa, particularly those that are commercially important, and how food web and body size factors differ in their influence on Hg and Se patterns. We compared Hg and Se content among marine fish and invertebrate taxa collected from Long Island, NY, and examined associations between Hg, Se, body length, trophic level (measured by δ(15N and degree of pelagic feeding (measured by δ(13C. Finfish, particularly shark, had high Hg content whereas bivalves generally had high Se content. Both taxonomic differences and variability were larger for Hg than Se, and Hg content explained most of the variation in Hg:Se molar ratios among taxa. Finally, Hg was more strongly associated with length and trophic level across taxa than Se, consistent with a greater degree of Hg bioaccumulation in the body over time, and biomagnification through the food web, respectively. Overall, our findings indicate distinct taxonomic and ecological Hg and Se patterns in commercially important marine biota, and these patterns have nutritional and toxicological implications for seafood-consuming wildlife and humans.

  1. Radiological dose conversion factors for generic non-human biota used for screening potential ecological impacts

    International Nuclear Information System (INIS)

    Protection of non-human biota from radionuclides in the environment is an important aspect of many environmental assessments. Biosphere transport models can be used to estimate radionuclide concentrations in plants and animals, and the radiological dose is calculated as the product of concentration and a dose-rate conversion factor (DCF). Here, we calculate and present DCF values for 99 radionuclides that can be used in a generic sense to estimate the dose to a wide variety of plants and animals. DCF values for internally incorporated radionuclides are based on the absorption of all emitted radiations from within the body. DCF values for external exposures include immersion in air, water, soil/sediment and vegetation. We implicitly include the energy from the decay progeny if they have a half-life of less than 1 day, to be consistent with many biosphere transport models. The DCF values can be used for simple screening of potential doses in assessments where a specific target organism cannot be defined. (author)

  2. Contrasting food web factor and body size relationships with Hg and Se concentrations in marine biota.

    Science.gov (United States)

    Karimi, Roxanne; Frisk, Michael; Fisher, Nicholas S

    2013-01-01

    Marine fish and shellfish are primary sources of human exposure to mercury, a potentially toxic metal, and selenium, an essential element that may protect against mercury bioaccumulation and toxicity. Yet we lack a thorough understanding of Hg and Se patterns in common marine taxa, particularly those that are commercially important, and how food web and body size factors differ in their influence on Hg and Se patterns. We compared Hg and Se content among marine fish and invertebrate taxa collected from Long Island, NY, and examined associations between Hg, Se, body length, trophic level (measured by δ(15)N) and degree of pelagic feeding (measured by δ(13)C). Finfish, particularly shark, had high Hg content whereas bivalves generally had high Se content. Both taxonomic differences and variability were larger for Hg than Se, and Hg content explained most of the variation in Hg:Se molar ratios among taxa. Finally, Hg was more strongly associated with length and trophic level across taxa than Se, consistent with a greater degree of Hg bioaccumulation in the body over time, and biomagnification through the food web, respectively. Overall, our findings indicate distinct taxonomic and ecological Hg and Se patterns in commercially important marine biota, and these patterns have nutritional and toxicological implications for seafood-consuming wildlife and humans. PMID:24019976

  3. Abiotic Protein Fragmentation by Manganese Oxide: Implications for a Mechanism to Supply Soil Biota with Oligopeptides.

    Science.gov (United States)

    Reardon, Patrick N; Chacon, Stephany S; Walter, Eric D; Bowden, Mark E; Washton, Nancy M; Kleber, Markus

    2016-04-01

    The ability of plants and microorganisms to take up organic nitrogen in the form of free amino acids and oligopeptides has received increasing attention over the last two decades, yet the mechanisms for the formation of such compounds in soil environments remain poorly understood. We used Nuclear Magnetic Resonance (NMR) and Electron Paramagnetic Resonance (EPR) spectroscopies to distinguish the reaction of a model protein with a pedogenic oxide (Birnessite, MnO2) from its response to a phyllosilicate (Kaolinite). Our data demonstrate that birnessite fragments the model protein while kaolinite does not, resulting in soluble peptides that would be available to soil biota and confirming the existence of an abiotic pathway for the formation of organic nitrogen compounds for direct uptake by plants and microorganisms. The absence of reduced Mn(II) in the solution suggests that birnessite acts as a catalyst rather than an oxidant in this reaction. NMR and EPR spectroscopies are shown to be valuable tools to observe these reactions and capture the extent of protein transformation together with the extent of mineral response. PMID:26974439

  4. A sinemydid turtle from the Jehol Biota provides insights into the basal divergence of crown turtles.

    Science.gov (United States)

    Zhou, Chang-Fu; Rabi, Márton

    2015-01-01

    Morphological phylogenies stand in a major conflict with molecular hypotheses regarding the phylogeny of Cryptodira, the most diverse and widely distributed clade of extant turtles. However, molecular hypotheses are often considered a better estimate of phylogeny given that it is more consistent with the stratigraphic and geographic distribution of extinct taxa. That morphology fails to reproduce the molecular topology partly originates from problematic character polarization due to yet another contradiction around the composition of the cryptodiran stem lineage. Extinct sinemydids are one of these problematic clades: they have been either placed among stem-cryptodires, stem-chelonioid sea turtles, or even stem-turtles. A new sinemydid from the Early Cretaceous Jehol Biota (Yixian Formation, Barremian-Early Aptian) of China, Xiaochelys ningchengensis gen. et sp. nov., allows for a reassessment of the phylogenetic position of Sinemydidae. Our analysis indicates that sinemydids mostly share symplesiomorphies with sea turtles and their purported placement outside the crown-group of turtles is an artefact of previous datasets. The best current phylogenetic estimate is therefore that sinemydids are part of the stem lineage of Cryptodira together with an array of other Jurassic to Cretaceous taxa. Our study further emphasises the importance of using molecular scaffolds in global turtle analyses.

  5. Sinobaatar gen. Nov.: First multituberculate from the Jehol Biota of Liaoning, Northeast China

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A multituberculate skeleton from the Lower Cretaceous Yixian Formation at Dawangzhangzi, Lingyuan City, Liaoning Province, Northeast China, provides new morphological information for early multituberculates. The specimen is the holotype of Sinobaatar lingyuanensis gen. et sp. nov. It has a narrow skull that lacks the superorbital crest or postorbital process. The dental formula is 3·?·5·2/1·0·3·2. The dental morphology, especially that of cheek teeth, of S. lingyuanensis is similar to that of Eobaatar, which places it in the family Eobaataridae. The postcranial skeleton of Sinobaatar is similar to that of other multituberculates. As in Holotheria, Metatarsal V of Sinobaatar articulates only with the cuboid and has no contact with the calcaneus, which probably represents the primitive condition of multituberculates. Nine carpals of Sinobaatar resemble those of Zhangheotherium, except the centrale being larger than the trapezoid. The dental features of Sinobaatar show again that eobaatarids are obviously intermediate between Late Jurassic multituberculates and the later forms. Because eobaatarids are only known from the Early Cretaceous, the finding of Sinobaatar, therefore, supports that the age of the Jehol Biota is most likely Early Cretaceous.

  6. Identifying Canadian freshwater fishes through DNA barcodes.

    Directory of Open Access Journals (Sweden)

    Nicolas Hubert

    Full Text Available BACKGROUND: DNA barcoding aims to provide an efficient method for species-level identifications using an array of species specific molecular tags derived from the 5' region of the mitochondrial cytochrome c oxidase I (COI gene. The efficiency of the method hinges on the degree of sequence divergence among species and species-level identifications are relatively straightforward when the average genetic distance among individuals within a species does not exceed the average genetic distance between sister species. Fishes constitute a highly diverse group of vertebrates that exhibit deep phenotypic changes during development. In this context, the identification of fish species is challenging and DNA barcoding provide new perspectives in ecology and systematics of fishes. Here we examined the degree to which DNA barcoding discriminate freshwater fish species from the well-known Canadian fauna, which currently encompasses nearly 200 species, some which are of high economic value like salmons and sturgeons. METHODOLOGY/PRINCIPAL FINDINGS: We bi-directionally sequenced the standard 652 bp "barcode" region of COI for 1360 individuals belonging to 190 of the 203 Canadian freshwater fish species (95%. Most species were represented by multiple individuals (7.6 on average, the majority of which were retained as voucher specimens. The average genetic distance was 27 fold higher between species than within species, as K2P distance estimates averaged 8.3% among congeners and only 0.3% among concpecifics. However, shared polymorphism between sister-species was detected in 15 species (8% of the cases. The distribution of K2P distance between individuals and species overlapped and identifications were only possible to species group using DNA barcodes in these cases. Conversely, deep hidden genetic divergence was revealed within two species, suggesting the presence of cryptic species. CONCLUSIONS/SIGNIFICANCE: The present study evidenced that freshwater fish

  7. New approaches for the mass spectrometric determination of trace concentrations and congener group patterns of chlorinated paraffins in biota

    OpenAIRE

    Reth, Margot

    2006-01-01

    The determination of chlorinated paraffins (CPs) in the environment is important, since CPs are persistent, bioaccumulative and toxic. However, the analysis of these complex mixtures containing thousands of isomers is also a demanding task. CP analysis and especially the quantification of CPs are far from being well established. In this work, new methodologies were developed for the determination of CPs in biota by low-resolution mass spectrometry (LRMS). The use of expensiv...

  8. The Luoping biota: exceptional preservation, and new evidence on the Triassic recovery from end-Permian mass extinction

    OpenAIRE

    Hu, Shi-xue; Zhang, Qi-yue; Chen, Zhong-Qiang; Zhou, Chang-Yong; Lü, Tao; XIE, TAO; Wen, Wen; Huang, Jin-yuan; Benton, Michael J.

    2010-01-01

    The timing and nature of biotic recovery from the devastating end-Permian mass extinction (252 Ma) are much debated. New studies in South China suggest that complex marine ecosystems did not become re-established until the middle–late Anisian (Middle Triassic), much later than had been proposed by some. The recently discovered exceptionally preserved Luoping biota from the Anisian Stage of the Middle Triassic, Yunnan Province and southwest China shows this final stage of community assembly on...

  9. The Biocontrol Agent Phlebiopsis gigantea: Efficacy and Impacts on the Stump Bacterial Biota and Conifer tree Defences

    OpenAIRE

    Sun, Hui

    2011-01-01

    Phlebiopsis gigantea has been for a long time known as a strong competitor against Heterobasidion annosum and intensively applied as a biological control agent on stump surfaces of Picea abies in Fennoscandia. However, the mechanism underlying its antagonistic activity is still unknown. A primary concern is the possible impact of P. gigantea treatment on resident non-target microbial biota of conifer stumps. Additional risk factor is the potential of P. gigantea to acquire a necrotrophic habi...

  10. Assessment of doses to non-human biota: Review of developments and demonstration assessment for Olkiluoto repository

    Energy Technology Data Exchange (ETDEWEB)

    Smith, K. [Carol Robinson Enviros Consulting Ltd, Edinburgh (United Kingdom)

    2006-12-15

    This report provides a summary of work commissioned by Posiva Oy and undertaken by Enviros Consulting Ltd to support the development of a strategy for the assessment of environmental impacts from ionising radiation associated with the Olkiluoto waste repository, Finland, as part of the development of the Posiva Safety Case Portfolio. This project included a review of the development of international policies and standards related to protection of biota from the effects of ionizing radiation and of biota assessment methodologies, paying particular attention to those that have been applied to waste repository performance assessments. On the basis of this review, recommendations were developed on the most appropriate methodology to apply in order to assess the impact of radioactive releases from the planned spent fuel repository in Olkiluoto. A test-case was developed, in collaboration with staff from Posiva and Facilia AB, and an assessment was performed. The results and experience of which were analysed and summarised to develop recommendations for a future strategy. The test case highlighted some significant data gaps related to the assessment of impacts to both generic biota types and to interest species. In particular, concentration ratios for generic carnivorous mammals and migratory species such as moose that may consume food from multiple ecosystems and dose conversion factors for large burrowing (i.e. hibernating) mammals. However, in general terms, the dose rates predicted for all organism types were several orders of magnitude below those at which population effects would be expected to be observed and those at which effects on the individual may be anticipated. There would therefore be scope for simplifying the approach applied, although there would be value in performing a sensitivity analysis to ensure that the simplification is applied appropriately. There would also be value in ensuring consistency of the developing approach for non-human biota with

  11. Impressions of the Biota Associated With Waterfalls and Cascades from a Holocene Tufa in the Zrmanja River Canyon, Croatia

    OpenAIRE

    Pavlović, G.; Zupanić, J.; Prohić, E.; Tibljaš, D.

    2002-01-01

    The following types of calcified deposits characterize Holocene waterfall tufas in the Zrmanja river: mossy deposits, algally laminated crusts and algally coated grains. Petrological examination revealed, that abundant organic remains belonging to mosses and algae provide supporting material, over which tufa accretion takes place, leaving well-defined impressions of the biota. Postgenetic features like meniscus, isopachous and drusy mosaic calcite spar cementation, as well as aggradational ne...

  12. Resolving and modelling trace metal partitioning in a freshwater sediment

    International Nuclear Information System (INIS)

    Elevated concentrations of trace metals in sediments pose toxicological risks to biota and may impair water quality. the sediment-water interface is the site where gradients in physical, chemical and biological properties are the greatest. Both chemical and microbiological transformation processes are responsible for cycling elements between water and sediments. (Author)

  13. Gastric cryptosporidiosis in freshwater angelfish (Pterophyllum scalare).

    Science.gov (United States)

    Murphy, Brian G; Bradway, Daniel; Walsh, Timothy; Sanders, George E; Snekvik, Kevin

    2009-09-01

    A freshwater angelfish (Pterophyllum scalare) hatchery experienced variable levels of emaciation, poor growth rates, swollen coelomic cavities, anorexia, listlessness, and increased mortality within their fish. Multiple chemotherapeutic trials had been attempted without success. In affected fish, large numbers of protozoa were identified both histologically and ultrastructurally associated with the gastric mucosa. The youngest cohort of parasitized fish was the most severely affected and demonstrated the greatest morbidity and mortality. The protozoa were morphologically most consistent with Cryptosporidium. All of the protozoan life stages were identified ultrastructurally and protozoal genomic DNA was isolated from parasitized tissue viscera and sequenced. Histological, ultrastructural, genetic, and phylogenetic analyses confirmed this protozoal organism to be a novel species of Cryptosporidium. PMID:19737774

  14. Eutrophication of freshwater and marine ecosystems

    Science.gov (United States)

    Smith, Val H.; Joye, Samantha B.; Howarth, Robert W.

    2006-01-01

    Initial understanding of the links between nutrients and aquatic productivity originated in Europe in the early 1900s, and our knowledge base has expanded greatly during the past 40 yr. This explosion of eutrophication-related research has made it unequivocally clear that a comprehensive strategy to prevent excessive amounts of nitrogen and phosphorus from entering our waterways is needed to protect our lakes, rivers, and coasts from water quality deterioration. However, despite these very significant advances, cultural eutrophication remains one of the foremost problems for protecting our valuable surface water resources. The papers in this special issue provide a valuable cross section and synthesis of our current understanding of both freshwater and marine eutrophication science. They also serve to identify gaps in our knowledge and will help to guide future research.

  15. Freshwater snail consumption and angiostrongyliasis in Malaya.

    Science.gov (United States)

    Liat, L B; Fong, Y L; Krishnansamy, M; Ramachandran, P; Mansor, S

    1978-06-01

    A survey of the freshwater snails, Pila scutata and Bellamyia ingallsiana, as food consumed by the local population was carried out in Peninsular Malaysia. Of these two species the first is preferred; the sizes favoured are between 25--40 mm. Pila snails were found to be consumed by the three communities, viz. Malay, Chinese and Indian, in different ways. The various methods of preparing the snails for consumption are described. P. scutata is an intermediate host of the rat-lung worm, Angiostrongylus malaysiensis. As this worm presumably is the causative agent of human eosinophilic meningoencephalitis, the eating habits of the three races in consuming the snail in relation to the epidemiology of the disease was also discussed. PMID:726037

  16. Freshwater algae of the Nevada Test Site

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, W.D.; Giles, K.R.

    1979-06-01

    Fifty-two species of freshwater algae were identified in samples collected from the eight known natural springs of the Nevada Test Site. Although several species were widespread, 29 species were site specific. Diatoms provided the greatest variety of species at each spring. Three-fifths of all algal species encountered were diatoms. Well-developed mats of filamentous green algae (Chlorophyta) were common in many of the water tanks associated with the springs and accounted for most of the algal biomass. Major nutrients were adequate, if not abundant, in most spring waters - growth being limited primarily by light and physical habitat. There was some evidence of cesium-137 bioconcentration by algae at several of the springs.

  17. Effects of water hardness and alkalinity on the toxicity of uranium to a tropical freshwater hydra (Hydra viridissima).

    Science.gov (United States)

    Riethmuller, N; Markich, S J; Van Dam, R A; Parry, D

    2001-01-01

    In tropical Australian freshwaters, uranium (U) is of potential ecotoxicological concern, largely as a consequence of mining activities. Although the toxicity of uranium to Australian freshwater biota is comprehensive, by world standards, few data are available on the effects of physicochemical variables, such as hardness, alkalinity, pH and organic matter, on uranium speciation and bioavailability. This study determined the individual effects of water hardness (6.6, 165 and 330 mg l(-1) as CaCO3) and alkalinity (4.0 and 102 mg l(-1) as CaCO3), at a constant pH (6.0), on the toxicity (96 h population growth) of uranium to Hydra viridissima (green hydra). A 50-fold increase in hardness (Ca and Mg concentration) resulted in a 92% (two-fold) decrease in the toxicity of uranium to H. viridissima [i.e. an increase in the EC50 value and 95% confidence interval from 114 (107-121) to 219 (192-246) µg l(-1)]. Conversely, at a constant hardness (165 mg l-1 as CaCO3), the toxicity of uranium to H. viridissima was not significantly (P > 0.05) affected by a 25-fold increase in alkalinity (carbonate concentration) [i.e. EC50 values of 177 (166-188) and 171 (150-192) µg l(-1) at 4.0 and 102 mg l(-1) as CaCO3, respectively]. A knowledge of the relationship between water chemistry variables, including hardness and alkalinity, and uranium toxicity is useful for predicting the potential ecological detriment in aquatic systems, and can be used to relax national water quality guidelines on a site-specific basis.

  18. Molecular phylogeny and phylogeography of the Australian freshwater fish genus Galaxiella, with an emphasis on dwarf galaxias (G. pusilla).

    Science.gov (United States)

    Unmack, Peter J; Bagley, Justin C; Adams, Mark; Hammer, Michael P; Johnson, Jerald B

    2012-01-01

    The freshwater fauna of Southern Australia is primarily restricted to the southwestern and southeastern corners of the continent, and is separated by a large, arid region that is inhospitable to this biota. This geographic phenomenon has attracted considerable interest from biogeographers looking to explain evolutionary diversification in this region. Here, we employed phylogenetic and phylogeographic approaches to evaluate the effect of this barrier on a group of four galaxiid fish species (Galaxiella) endemic to temperate Southern Australia. We also tested if continental shelf width has influenced connectivity among populations during low sea levels when rivers, now isolated, could have been connected. We addressed these questions by sampling each species across its range using multiple molecular markers (mitochondrial cytochrome b sequences, nuclear S7 intron sequences, and 49 allozyme loci). These data also allowed us to assess species boundaries, to refine phylogenetic affinities, and to estimate species ages. Interestingly, we found compelling evidence for cryptic species in G. pusilla, manifesting as allopatric eastern and western taxa. Our combined phylogeny and dating analysis point to an origin for the genus dating to the early Cenozoic, with three of the four species originating during the Oligocene-Miocene. Each Galaxiella species showed high levels of genetic divergences between all but the most proximate populations. Despite extensive drainage connections during recent low sea levels in southeastern Australia, populations of both species within G. pusilla maintained high levels of genetic structure. All populations experienced Late Pleistocene-Holocene population growth, possibly in response to the relaxation of arid conditions after the last glacial maximum. High levels of genetic divergence and the discovery of new cryptic species have important implications for the conservation of this already threatened group of freshwater species. PMID:22693638

  19. Deriving freshwater quality criteria of sulphocyanic sodium for the protection of aquatic life in China

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    The freshwater quality criteria of sulphocyanic sodium(NaSCN) were studied on the basis of the features of the aquaticbiota in China, and with Reference to U.S.EPA's guidelines. Acutetests were performed on twelve different domestic species todetermine 48h-EC50/96h-EC50 (or 96h-LC50) values for NaSCN. 21dsurvival-reproduction test with Daphnia magna, 60d fry-juvenilepart life stage test with Carassius auratus gibelio and 96h growthinhibition test with Lemna minor were also conducted to estimatelower chronic limit/upper chronic limit values. In the acute tests,D.magna was the most sensitive species to NaSCN followed by Tilapiamossambia, Cyprinus carpio and C.auratus gibelio in turn. The finalacute value of NaSCN was 2.699 mg/L. In the chronic tests,reproduction of daphnids were significantly reduced by NaSCN at 1.0mg/L. Acute-to-chronic ratios ranged from 5.96 to 19.1. A finalchronic value of 0.2530 mg/L was obtained and a final plant valuewas 1346 mg/L. A criterion maximum concentration (1.349 mg/L) anda criterion continuous concentration (0.2530 mg/L) were derivedrespectively. The results of this study may provide useful data toderive national WQC for NaSCN as well as the procedures of derivingWQC of other chemicals for the protection of aquatic biota in China.

  20. Effects of cadmium stress and sorption kinetics on tropical freshwater periphytic communities in indoor mesocosm experiments

    International Nuclear Information System (INIS)

    Understanding the cause and effect relationship between stressors and biota is crucial for the effective management, restoration and preservation of aquatic systems. The objective of the present study was to assess the effects of five Cd concentrations on tropical periphyton community growth, Cd accumulation kinetics, as well as the effects of Cd on diatom community structure and composition. Natural periphyton communities were transferred to artificial stream chambers and exposed to Cd concentrations of 0.005, 0.01, 0.03, 0.05 and 0.1 mg.L−1. Metal accumulation (total and intracellular) in biofilms, dry weight and ash-free dry mass, growth rate, algal cell density and diatom community composition were analysed on samples collected after 1, 2 and 4 weeks of colonization. Periphyton growth and development were significantly lowered by Cd concentrations > 0.03 mg.L−1. High Cd accumulation capacity by periphyton was demonstrated with total and intracellular Cd content in biofilms reflecting the effects of concentrations of Cd in the culture media and exposure duration. Total and intracellular Cd content generally increased in treatments in the order 0.005 −1 at any sampling time with increasing level of accumulated Cd with duration of exposure in all the systems. Shifts in species composition (development of more resistant species like Achnanthidium minutissimum and reduction of sensitive ones like Diatoma vulgare, Navicula viridula and Navicula cryptocephala), decreases in species richness and diversity and morphological alterations (deformities) of diatom cells with increasing Cd concentration and exposure duration were observed. The results give valuable information on Cd impact of freshwater biofilms. -- Highlights: ► We investigated toxicity and sorption kinetics of Cd on periphyton communities. ► [Cd] > 0.03 mg.L−1 lowers growth. ► Absorbed Cd was a function of duration of exposure and [Cd]. ► Changes in community composition were recorded.

  1. A comparison of the response of Simocephalus mixtus (Cladocera) and Daphnia magna to contaminated freshwater sediments.

    Science.gov (United States)

    Martínez-Jerónimo, Fernando; Cruz-Cisneros, Jade Lizette; García-Hernández, Leonardo

    2008-09-01

    The southeast region of Mexico is characterized by intensive oil industry activities carried out by the national public enterprise Petróleos Mexicanos (PEMEX). The freshwater lagoon "El Limón", located in the municipality of Macuspana, state of Tabasco, Mexico, has received over 40 years discharges of untreated waste waters from the Petrochemical Complex "Ciudad PEMEX", located on the border of the lagoon. To assess the toxicity of the sediments and, hence, to obtain information on the biological effects of these contaminating discharges, the cladoceran Simocephalus mixtus was used as a test organism in acute (48h) and chronic (12d) toxicity assays. For comparison purposes, bioassays were also conducted with the reference cladoceran Daphnia magna. The sediments of this lagoon contain important amounts of metals and hydrocarbons that have been accumulated over time; however, the acute tests only registered reduced lethal effects on the test organisms (maxima of 10% and 17% mortality for D. magna and S. mixtus, respectively). This may be due to low bioavailability of the pollutants present in the sediments. On the other hand, partial or total inhibition and delay in the start of reproduction, reduction in clutch sizes, reduced survival, as well as reduction in the size of adults and offspring were recorded in the chronic assays. The most evident chronic effects were found in S. mixtus; in this species, reproduction was inhibited up to 72%, whereas D. magna was only affected by 24%. We determined that S. mixtus is a more sensitive test organism than D. magna to assess whole-sediment toxicity in tropical environments, and that chronic exposure bioassays are required for an integrated sediment evaluation. The sediments from "El Limón" lagoon induced chronic intoxication responses and, therefore, remediation measures are urgently needed to recover environmental conditions suitable for the development of its aquatic biota. PMID:18573528

  2. River dolphins can act as population trend indicators in degraded freshwater systems.

    Directory of Open Access Journals (Sweden)

    Samuel T Turvey

    Full Text Available Conservation attention on charismatic large vertebrates such as dolphins is often supported by the suggestion that these species represent surrogates for wider biodiversity, or act as indicators of ecosystem health. However, their capacity to act as indicators of patterns or trends in regional biodiversity has rarely been tested. An extensive new dataset of >300 last-sighting records for the Yangtze River dolphin or baiji and two formerly economically important fishes, the Yangtze paddlefish and Reeves' shad, all of which are probably now extinct in the Yangtze, was collected during an interview survey of fishing communities across the middle-lower Yangtze drainage. Untransformed last-sighting date frequency distributions for these species show similar decline curves over time, and the linear gradients of transformed last-sighting date series are not significantly different from each other, demonstrating that these species experienced correlated population declines in both timing and rate of decline. Whereas species may be expected to respond differently at the population level even in highly degraded ecosystems, highly vulnerable (e.g. migratory species can therefore display very similar responses to extrinsic threats, even if they represent otherwise very different taxonomic, biological and ecological groupings. Monitoring the status of river dolphins or other megafauna therefore has the potential to provide wider information on the status of other threatened components of sympatric freshwater biotas, and so represents a potentially important monitoring tool for conservation management. We also show that interview surveys can provide robust quantitative data on relative population dynamics of different species.

  3. Analysis of Selenium Concentrations in Biota and Sediment from Stewart Lake and the Middle Green River, 1995-1999: Evaluation of Phase IV Remediation

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report presents the analytical results and analysis of selenium concentrations in biota and sediment samples collected by the U.S. Fish and Wildlife Service...

  4. Accounting for the dissociating properties of organic chemicals in LCIA: an uncertainty analysis applied to micropollutants in the assessment of freshwater ecotoxicity.

    Science.gov (United States)

    Morais, Sérgio Alberto; Delerue-Matos, Cristina; Gabarrell, Xavier

    2013-03-15

    In life cycle impact assessment (LCIA) models, the sorption of the ionic fraction of dissociating organic chemicals is not adequately modeled because conventional non-polar partitioning models are applied. Therefore, high uncertainties are expected when modeling the mobility, as well as the bioavailability for uptake by exposed biota and degradation, of dissociating organic chemicals. Alternative regressions that account for the ionized fraction of a molecule to estimate fate parameters were applied to the USEtox model. The most sensitive model parameters in the estimation of ecotoxicological characterization factors (CFs) of micropollutants were evaluated by Monte Carlo analysis in both the default USEtox model and the alternative approach. Negligible differences of CFs values and 95% confidence limits between the two approaches were estimated for direct emissions to the freshwater compartment; however the default USEtox model overestimates CFs and the 95% confidence limits of basic compounds up to three orders and four orders of magnitude, respectively, relatively to the alternative approach for emissions to the agricultural soil compartment. For three emission scenarios, LCIA results show that the default USEtox model overestimates freshwater ecotoxicity impacts for the emission scenarios to agricultural soil by one order of magnitude, and larger confidence limits were estimated, relatively to the alternative approach. PMID:23434828

  5. Enantioselective analysis of non-steroidal anti-inflammatory drugs in freshwater fish based on microextraction with a supramolecular liquid and chiral liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Caballo, Carmen; Sicilia, Maria Dolores; Rubio, Soledad

    2015-06-01

    Toxicity of pharmaceuticals to aquatic biota is still largely unknown, and no research on the stereoselective toxicity of chiral drugs to these organisms has been undertaken to date. Because of the lack of analytical methods available for this purpose, this manuscript deals, for the first time, with the enantioselective analysis of the non-steroidal anti-inflammatory drugs (NSAIDs) ibuprofen, naproxen and ketoprofen in freshwater fish. The method was based on the microextraction of NSAIDs from fish muscle with a supramolecular liquid made up of inverted hexagonal aggregates of decanoic acid, their enantiomeric separation by liquid chromatography onto a (R)-1-naphthylglycine and 3,5-dinitrobenzoic acid stationary phase and quantification by tandem mass spectrometry. Limits of quantitation (LOQs) for NSAID enantiomers were in the range 1.7-3.3 ng g(-1). Absolute recoveries were from 97 to 104 %, which indicated the high extraction efficiency of the supramolecular solvent. Extraction equilibrium conditions were reached after 10 min which permitted fast sample treatment. Relative standard deviations for enantiomers in fish muscle were always below 6 %. Isotopically labelled internal standards were used to compensate for matrix interferences. The method in-house validation was carried out with the Oncorhynchus mykiss species, and it was applied to the determination of NSAID enantiomers in different fortified freshwater fish species (Alburnus alburnus, Lepomis gibbosus, Micropterus salmoides, O. mykiss and Cyprinus carpio). PMID:25869485

  6. Free-living nematodes in the freshwater food web: a review.

    Science.gov (United States)

    Majdi, Nabil; Traunspurger, Walter

    2015-03-01

    Free-living nematodes are well-recognized as an abundant and ubiquitous component of benthic communities in inland waters. Compelling evidence from soil and marine ecosystems has highlighted the importance of nematodes as trophic intermediaries between microbial production and higher trophic levels. However, the paucity of empirical evidence of their role in freshwater ecosystems has hampered their inclusion in our understanding of freshwater food web functioning. This literature survey provides an overview of research efforts in the field of freshwater nematode ecology and of the complex trophic interactions between free-living nematodes and microbes, other meiofauna, macro-invertebrates, and fishes. Based on an analysis of the relevant literature and an appreciation of the potential of emerging approaches for the evaluation of nematode trophic ecology, we point out research gaps and recommend relevant directions for further research. The latter include (i) interactions of nematodes with protozoans and fungi; (ii) nonconsumptive effects of nematodes on microbial activity and the effects of nematodes on associated key ecosystem processes (decomposition, primary production); and (iii) the feeding selectivity and intraspecific feeding variability of nematodes and their potential impacts on the structure of benthic communities. PMID:25861114

  7. Free-living nematodes in the freshwater food web: a review.

    Science.gov (United States)

    Majdi, Nabil; Traunspurger, Walter

    2015-03-01

    Free-living nematodes are well-recognized as an abundant and ubiquitous component of benthic communities in inland waters. Compelling evidence from soil and marine ecosystems has highlighted the importance of nematodes as trophic intermediaries between microbial production and higher trophic levels. However, the paucity of empirical evidence of their role in freshwater ecosystems has hampered their inclusion in our understanding of freshwater food web functioning. This literature survey provides an overview of research efforts in the field of freshwater nematode ecology and of the complex trophic interactions between free-living nematodes and microbes, other meiofauna, macro-invertebrates, and fishes. Based on an analysis of the relevant literature and an appreciation of the potential of emerging approaches for the evaluation of nematode trophic ecology, we point out research gaps and recommend relevant directions for further research. The latter include (i) interactions of nematodes with protozoans and fungi; (ii) nonconsumptive effects of nematodes on microbial activity and the effects of nematodes on associated key ecosystem processes (decomposition, primary production); and (iii) the feeding selectivity and intraspecific feeding variability of nematodes and their potential impacts on the structure of benthic communities.

  8. Use of the Biotic Ligand Model to predict metal toxicity to aquatic biota in areas of differing geology

    Science.gov (United States)

    Smith, Kathleen S.

    2005-01-01

    This work evaluates the use of the biotic ligand model (BLM), an aquatic toxicity model, to predict toxic effects of metals on aquatic biota in areas underlain by different rock types. The chemical composition of water, soil, and sediment is largely derived from the composition of the underlying rock. Geologic source materials control key attributes of water chemistry that affect metal toxicity to aquatic biota, including: 1) potentially toxic elements, 2) alkalinity, 3) total dissolved solids, and 4) soluble major elements, such as Ca and Mg, which contribute to water hardness. Miller (2002) compiled chemical data for water samples collected in watersheds underlain by ten different rock types, and in a mineralized area in western Colorado. He found that each rock type has a unique range of water chemistry. In this study, the ten rock types were grouped into two general categories, igneous and sedimentary. Water collected in watersheds underlain by sedimentary rock has higher mean pH, alkalinity, and calcium concentrations than water collected in watersheds underlain by igneous rock. Water collected in the mineralized area had elevated concentrations of calcium and sulfate in addition to other chemical constituents. Miller's water-chemistry data were used in the BLM (computer program) to determine copper and zinc toxicity to Daphnia magna. Modeling results show that waters from watersheds underlain by different rock types have characteristic ranges of predicted LC 50 values (a measurement of aquatic toxicity) for copper and zinc, with watersheds underlain by igneous rock having lower predicted LC 50 values than watersheds underlain by sedimentary rock. Lower predicted LC 50 values suggest that aquatic biota in watersheds underlain by igneous rock may be more vulnerable to copper and zinc inputs than aquatic biota in watersheds underlain by sedimentary rock. For both copper and zinc, there is a trend of increasing predicted LC 50 values with increasing dissolved

  9. The effect of native and introduced biofuel crops on the composition of soil biota communities

    Science.gov (United States)

    Frouz, Jan; Hedenec, Petr

    2016-04-01

    Biofuel crops are an accepted alternative to fossil fuels, but little is known about the ecological impact of their production. The aim of this contribution is to study the effect of native (Salix viminalis and Phalaris arundinacea) and introduced (Helianthus tuberosus, Reynoutria sachalinensis and Silphium perfoliatum) biofuel crop plantations on the soil biota in comparison with cultural meadow vegetation used as control. The study was performed as part of a split plot field experiment of the Crop Research Institute in the city of Chomutov (Czech Republic). The composition of the soil meso- and macrofauna community, composition of the cultivable fraction of the soil fungal community, cellulose decomposition (using litter bags), microbial biomass, basal soil respiration and PLFA composition (incl. F/B ratio) were studied in each site. The C:N ratio and content of polyphenols differed among plant species, but these results could not be considered significant between introduced and native plant species. Abundance of the soil meso- and macrofauna was higher in field sites planted with S. viminalis and P. arundinacea than those planted with S. perfoliatum, H. tuberosus and R. sachalinensis. RDA and Monte Carlo Permutation Test showed that the composition of the faunal community differed significantly between various native and introduced plants. Significantly different basal soil respiration was found in sites planted with various energy crops; however, this difference was not significant between native and introduced species. Microbial biomass carbon and cellulose decomposition did not exhibit any statistical differences among the biofuel crops. The largest statistically significant difference we found was in the content of actinobacterial and bacterial (bacteria, G+ bacteria and G- bacteria) PLFA in sites overgrown by P. arundinacea compared to introduced as well as native biofuel crops. In conclusion, certain parameters significantly differ between various native

  10. Toxicological impact of cadmium-based quantum dots towards aquatic biota: Effect of natural sunlight exposure.

    Science.gov (United States)

    Silva, B F; Andreani, T; Gavina, A; Vieira, M N; Pereira, C M; Rocha-Santos, T; Pereira, R

    2016-07-01

    Cadmium-based quantum dots (QDs) are increasingly applied in existent and emerging technologies, especially in biological applications due to their exceptional photophysical and functionalization properties. However, they are very toxic compounds due to the high reactive and toxic cadmium core. The present study aimed to determine the toxicity of three different QDs (CdS 380, CdS 480 and CdSeS/ZnS) before and after the exposure of suspensions to sunlight, in order to assess the effect of environmentally relevant irradiation levels in their toxicity, which will act after their release to the environment. Therefore, a battery of ecotoxicological tests was performed with organisms that cover different functional and trophic levels, such as Vibrio fischeri, Raphidocelis subcapitata, Chlorella vulgaris and Daphnia magna. The results showed that core-shell type QDs showed lower toxic effects to V. fischeri in comparison to core type QDs before sunlight exposure. However, after sunlight exposure, there was a decrease of CdS 380 and CdS 480 QD toxicity to bacterium. Also, after sunlight exposure, an effective decrease of CdSeS/ZnS and CdS 480 toxicity for D. magna and R. subcapitata, and an evident increase in CdS 380 QD toxicity, at least for D. magna, were observed. The results of this study suggest that sunlight exposure has an effect in the aggregation and precipitation reactions of larger QDs, causing the degradation of functional groups and formation of larger bulks which may be less prone to photo-oxidation due to their diminished surface area. The same aggregation behaviour after sunlight exposure was observed for bare QDs. These results further emphasize that the shell of QDs seems to make them less harmful to aquatic biota, both under standard environmental conditions and after the exposure to a relevant abiotic factor like sunlight. PMID:27162069

  11. Interaction of the reasons for the mass biota extinctions in the Phanerozoic

    Science.gov (United States)

    Barash, M. S.

    2013-11-01

    The consideration of the conditions during the mass extinctions has shown that a series of factors, including mutually independent tectonic movements, variations in the sea level and climate, volcanism, asteroid impacts, changes in the composition of the atmosphere and hydrosphere, the dimming of the atmosphere by aerosols at volcanism and impact events, etc., had a harmful affect during some periods of time (a hundred thousand years to millions of years). Some of the listed events occurred for a long period of time and could not have caused the abrupt catastrophic death of organisms on a global scale. The examination of the hierarchy of the major events allows us to distinguish the primary terrestrial (volcanism) and cosmic (impact events) reasons for the mass extinctions. The coeval mutually independent events testify to the common external reasons for the higher order beyond the solar system. These events are suggested to be related with the orbital movement of the solar system around the galaxy's center, the intersection of the galactic branches, and the oscillations of the solar system's position relative to the galactic plane. These reasons influence the processes on the Earth, including the internal and external geospheres, and activate the impacts of asteroids and comets. Under their effect, two main subsequences of events are developed: terrestrial, leading to intense volcanism, and cosmic impact events. In both cases, harmful chemical elements and aerosols are vented to the atmosphere, thus resulting in the greenhouse effect, warming, the dimming of the atmosphere, the prevention of photosynthesis, the ocean's stagnation, and anoxia with the following reduction of the bioproductivity, the destruction of the food chains, and the extinction of a significant part of the biota.

  12. Secondary UV radiation from biota as a proof of radiation hormesis and Gurwitsch phenomena

    International Nuclear Information System (INIS)

    High (large) and low (small) doses of ionizing radiation consistently induce opposite physiologic effects in biological systems. The effects of low doses cannot be inferred by interpolation between the result from groups exposed to high doses and controls irradiated only by Natural Background Radiation. Stimulation NBR ('bio-positive') effects by low-level doses of ionizing radiation is called radiation hormesis. It is still a controversial idea; however it was found that some biological objects (yeast, sees, animals) after γ-irradiation by low-level doses (10-50 times more NBR) can increase their development. The results of the researches demonstrate that the excitation of living systems by ionizing radiation (high energy, low doses) produces among other hydrogen peroxide which initiates prolonged secondary emission that can influence biota and activate many important processes in biological systems. On the other hand it is well known that after water irradiation by ionizing radiation as the product of radiolysis concentration of hydrogen peroxide has been received. The spectral analysis of this secondary emission confirmed the contribution of the UV component to the total emission. This secondary radiation can play a very important role in the intercellular communication. The influence of hydrogen peroxide on glycine has been examined. I have measured secondary emission from Gly using the Single Photon Counting device SPC. The data obtained made possible at least a partial understanding of the radiation hormesis phenomenon and suggest closer relationship to mitogenetic radiation. I propose deexcitation processes in biomolecules as a common denominator of UV and ionizing radiation interacting with living cells, underlying both radiation hormesis and mitogenetic effect. Based on the above experiments and other authors' reports it is postulated that low-level doses of ionizing radiation through radiolysis products (among others hydrogen peroxide) generate UV

  13. Chemical analysis and genotoxicity of high molecular mass PAH in sediment samples and biota

    International Nuclear Information System (INIS)

    A normal phase liquid chromatography (NPLC) method was used to fractionate the organic extracts of prepared from coal tar-contaminated sediments from hamilton Harbor in Ontario and from Sydney Harbor in Nova Scotia into molecular mass classes. Each PAH fraction up to 302 amu was analyzed by GC-MS and fractions containing PAH with molecular masses greater than 302 amu were analyzed by atmospheric pressure chemical ionization (APCI) LC-MS.Each fraction was also subjected to Ames bioassays using a TA100-like strain of Salmonella typhimurium (YG1025 + S9). The 300/302 amu, 326/328 and 350/352 amu PAH fractions accounted for 25% of the total genotoxic response of the extract; these PAH constitute a substantial genotoxic burden. A number of 300, 302, 326, 350, 374 and 400 amu PAH were identified using APCI LC-MS and comparison with authentic standards. The non-polar aromatic extracts of bottom sediments, suspended sediments and zebra mussels from Hamilton Harbor were also examined by GC-MS, APCI LC-MS and genotoxicity bioassays. The profiles of the priority and high mass PAH in these samples were identical showing that all PAH up to and exceeding 400 amu were readily bioavailable to biota such as Zebra mussels. In addition, the pseudo faeces of the Zebra mussels and amphipod detritivores which fed on the pseudo faeces had chemical profiles identical to the Zebra mussels. Since many sport fish prize amphipods as food, this observation demonstrates a pathway for organic contaminants adsorbed to suspended sediments to enter the food chain of non-bottom-feeding fish in areas infested by Zebra mussels

  14. Diversity of the soil biota in burned areas of southern taiga forests (Tver oblast)

    Science.gov (United States)

    Gongalsky, K. B.; Zaitsev, A. S.; Korobushkin, D. I.; Saifutdinov, R. A.; Yazrikova, T. E.; Benediktova, A. I.; Gorbunova, A. Yu.; Gorshkova, I. A.; Butenko, K. O.; Kosina, N. V.; Lapygina, E. V.; Kuznetsova, D. M.; Rakhleeva, A. A.; Shakhab, S. V.

    2016-03-01

    Relations between soil biota diversity and its contribution to the performance of some ecosystem functions were assessed based on the results obtained in undisturbed and burned spruce forests near the Central Forest Nature Biosphere Reserve (Tver oblast). In August 2014, in two 4-year-old burned areas, abiotic parameters of the soils, indicators of the state of the microbial communities, the number, taxonomic diversity, and the abundance of the main groups of soil invertebrates (testate amoebae, nematodes, enchytraeids, mites, collembolans, and the mesofauna as a whole) were determined. In the soils of the burned areas, higher CO2, CH4, and N2O emissions were observed. The number of bacterial cells remained similar, and the total length of active mycelium was not significantly different. All this implies a certain intensification of biogenic processes promoting the mobilization of carbon and nitrogen after fire. The number of most of the groups of soil animals was lower (not always significantly) in the burned area than that in the soils of the undisturbed forests. The changes in the taxonomic diversity were specific for each taxon studied. Overall, the diversity of invertebrates was related to the litter thickness. However, the high taxonomic diversity of soil fauna did not always correspond to the active functioning of the ecosystem. Thus, for some taxa, a quite close correlation was found, for instance, between the total number of species (of testate amoebae in particular) and the berry crop, as well as between the soil mesofauna population and the dead wood stock. The total diversity of the investigated taxa included in the detrital trophic web was the most reliable indicator of the carbon stock in the burned areas.

  15. Impacts of new highways and subsequent landscape urbanization on stream habitat and biota

    Science.gov (United States)

    Wheeler, A.P.; Angermeier, P.L.; Rosenberger, A.E.

    2005-01-01

    New highways are pervasive, pernicious threats to stream ecosystems because of their short- and long-term physical, chemical, and biological impacts. Unfortunately, standard environmental impact statements (EISs) and environmental assessments (EAs) focus narrowly on the initial direct impacts of construction and ignore other long-term indirect impacts. More thorough consideration of highway impacts, and, ultimately, better land use decisions may be facilitated by conceptualizing highway development in three stages: initial highway construction, highway presence, and eventual landscape urbanization. Highway construction is characterized by localized physical disturbances, which generally subside through time. In contrast, highway presence and landscape urbanization are characterized by physical and chemical impacts that are temporally persistent. Although the impacts of highway presence and landscape urbanization are of similar natures, the impacts are of a greater magnitude and more widespread in the urbanization phase. Our review reveals that the landscape urbanization stage is clearly the greatest threat to stream habitat and biota, as stream ecosystems are sensitive to even low levels (biological consequences, we found few published investigations of its impacts on streams. Researchers know little about the occurrence, loading rates, and biotic responses to specific contaminants in highway runoff. Also needed is a detailed understanding of how highway crossings, especially culverts, affect fish populations via constraints on movement and how highway networks alter natural regimes (e.g., streamflow, temperature). Urbanization research topics that may yield especially useful results include a) the relative importance and biological effects of specific components of urban development - e.g., commercial or residential; b) the scenarios under which impacts are reversible; and c) the efficacy of mitigation measures - e.g., stormwater retention or treatment and

  16. Culture of Freshwater Prawns (Macrobrachium Rosenbergii) Using Geothermal Waste Water

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, William C.

    1978-01-01

    The farming of freshwater prawns (Macrobrachium rosenbergii) in geothermal-heated water has been demonstrated to be feasible in a non-tropical climate. The husbandry of prawns is being done in two outdoor raceway ponds, 9.1 m by 2.5 m and 29 m by 3.5 m that are 1.2 m deep. The ponds are not shielded from the ambient climate which during the winter months has recorded air temperatures as low as -20oC. A selected brood stock is held in a small spawning building where larvae are hatched in artificial saltwater and reared to the post-larvae stage which makes the facility self-supporting. This project is providing a model for potential investors to utilize the low-temperature geothermal resources in the western United States for warm water aquaculture. Zooplankton, macroscopic crusteans, from a local euthrophic lake are being fed to the post-larvae and adult prawns in addition to prepared commercial dry pelleted foods to keep operational costs at a minimum. Initial measurements of growth and weight gains indicate the production of two crops of prawns per year at seven to the pond is possible. No work on intensive culture has been done. Plans to enlarge the facility and do work on developing intensive culture are being considered.

  17. Genetic management guidelines for captive propagation of freshwater mussels (unionoidea)

    Science.gov (United States)

    Jones, J.W.; Hallerman, E.M.; Neves, R.J.

    2006-01-01

    Although the greatest global diversity of freshwater mussels (???300 species) resides in the United States, the superfamily Unionoidea is also the most imperiled taxon of animals in the nation. Thirty-five species are considered extinct, 70 species are listed as endangered or threatened, and approximately 100 more are species of conservation concern. To prevent additional species losses, biologists have developed methods for propagating juvenile mussels for release into the wild to restore or augment populations. Since 1997, mussel propagation facilities in the United States have released over 1 million juveniles of more than a dozen imperiled species, and survival of these juveniles in the wild has been documented. With the expectation of continued growth of these programs, agencies and facilities involved with mussel propagation must seriously consider the genetic implications of releasing captive-reared progeny. We propose 10 guidelines to help maintain the genetic resources of cultured and wild populations. Preservation of genetic diversity will require robust genetic analysis of source populations to define conservation units for valid species, subspecies, and unique populations. Hatchery protocols must be implemented that minimize risks of artificial selection and other genetic hazards affecting adaptive traits of progeny subsequently released to the wild. We advocate a pragmatic, adaptive approach to species recovery that incorporates the principles of conservation genetics into breeding programs, and prioritizes the immediate demographic needs of critically endangered mussel species.

  18. CHARACTERIZATION AND IDENTIFICATION OF FRESHWATER MICROALGAL STRAINS TOWARD BIOFUEL PRODUCTION

    Directory of Open Access Journals (Sweden)

    Xun Yang,

    2011-12-01

    Full Text Available Fifty-three algal cultures were isolated from freshwater lakes in Hainan, China. Four microalgal isolates were selected because they could be successfully cultivated at high density and demostrated a strong fluorescence after being stained with nile red. These cultures were identified as strains of Chlorella sp. C11, Chlamydomonas reinhardtii C22, Monoraphidium dybowskii C29, and Chlorella sp. HK12 through microscopic and 18S rDNA analysis. Under similar conditions, the lipid productivity of Chlorella sp. C11, Chla. reinhardtii C22, M. dybowskii C29 , and Chlorella sp. HK12 were 1.88, 2.79, 2.00, and 3.25 g L-1, respectively. Chla. reinhardtii C22 yielded a higher lipid content (51%, with a lower biomass concentration (5.47 g dwt L-1. Chlorella sp. HK12 reached a growth rate of 0.88 day-1 at OD540nm and yielded a biomass concentration of 7.56 g dwt L-1, with a high lipid content of 43%. Gas chromatography/ mass spectrometry analysis indicated that lipid fraction mainly comprises hydrocarbons including palmitic acid, stearic acid, oleic acid, linoleic acid, and linolenic acids. Our results suggest that Chlorella sp. HK12 is a promising species for biodiesel production, because of its high lipid productivity and a relatively high content of oleic acid.

  19. Cultivation of macroscopic marine algae and freshwater aquatic weeds. Progress report, May 1--December 31, 1976

    Energy Technology Data Exchange (ETDEWEB)

    Ryther, J. H.

    1977-01-01

    Research was divided between basic physiological studies of the growth and nutrient-uptake kinetics of macroscopic marine algae and the more applied problems involved in the selection of species and the development of inexpensive, non-energy intensive culture methods for growing seaweeds and freshwater plants as a biomass source for conversion to energy. Best growth of the seaweeds occurs at low (0.1 to 1.0 ..mu..molar) concentration of major nutrients, with ammonia as a nitrogen source, with rapid exchange of the culture medium (residence time of 0.05 days or less). Of 43 species of seaweeds evaluated, representatives of the large red alga genus Gracilaria appear most promising with potential yields, in a highly intensive culture system under optimal conditions, of some 129 metric dry tons per hectare per year (about half of which is organic). Non-intensive culture methods have yielded one-third to one-half that figure. Unexplained periodicity of growth and overgrowth by epiphytes remain the most critical constraint to large-scale seaweed culture. Freshwater weed species in culture include water hyacinth (Eichhornia crassipes), duckweed (Lemna minor), and Hydrilla vertecillata, with yields to date averaging 15, 4, and 8 g dry wt/m/sup 2//day, respectively. However, these plants have not yet been grown through the winter, so average annual yields are expected to be lower. In contrast to the seaweeds, the freshwater plants grow well at high nutrient concentrations and slow culture volume exchange rates (residence time ca. 20 days or more). Experiments were initiated on the recycling of digester residues from the fermentation of the freshwater and marine plants as a possible nutrient source for growth of the same species.

  20. Radiological benchmarks for screening contaminants of potential concern for effects on aquatic biota at Oak Ridge National Laboratory, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    A hazardous waste site may contain hundreds of contaminants; therefore, it is important to screen contaminants of potential concern for the ecological risk assessment. Often this screening is done as part of a screening assessment, the purpose of which is to evaluate the available data, identify data gaps, and screen contaminants of potential concern. Screening may be accomplished by using a set of toxicological benchmarks. These benchmarks are helpful in determining whether contaminants warrant further assessment or are at a level that requires no further attention. Unlike exposures to chemicals, which are expressed as the concentration in water or sediment, exposures to radionuclides are expressed as the dose rate received by the organism. The recommended acceptable dose rate to natural populations of aquatic biota is 1 rad d-1. Blaylock, Frank, and O'Neal provide formulas and exposure factors for estimating the dose rates to representative aquatic organisms. Those formulas were used herein to calculate the water and sediment concentrations that result in a total dose rate of 1 rad d-1 to fish for selected radionuclides. These radiological benchmarks are intended for use at the US Department of Energy's (DOE's) Oak Ridge Reservation and at the Portsmouth and Paducah gaseous diffusion plants as screening values only to show the nature and extent of contamination and identify the need for additional site-specific investigation

  1. Radiological benchmarks for screening contaminants of potential concern for effects on aquatic biota at Oak Ridge National Laboratory, Oak Ridge, Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-07-01

    A hazardous waste site may contain hundreds of contaminants; therefore, it is important to screen contaminants of potential concern for the ecological risk assessment. Often this screening is done as part of a screening assessment, the purpose of which is to evaluate the available data, identify data gaps, and screen contaminants of potential concern. Screening may be accomplished by using a set of toxicological benchmarks. These benchmarks are helpful in determining whether contaminants warrant further assessment or are at a level that requires no further attention. Unlike exposures to chemicals, which are expressed as the concentration in water or sediment, exposures to radionuclides are expressed as the dose rate received by the organism. The recommended acceptable dose rate to natural populations of aquatic biota is 1 rad d{sup {minus}1}. Blaylock, Frank, and O`Neal provide formulas and exposure factors for estimating the dose rates to representative aquatic organisms. Those formulas were used herein to calculate the water and sediment concentrations that result in a total dose rate of 1 rad d{sup {minus}1} to fish for selected radionuclides. These radiological benchmarks are intended for use at the US Department of Energy`s (DOE`s) Oak Ridge Reservation and at the Portsmouth and Paducah gaseous diffusion plants as screening values only to show the nature and extent of contamination and identify the need for additional site-specific investigation.

  2. Radiation Dose Assessment For The Biota Of Terrestrial Ecosystems In The Shoreline Zone Of The Chernobyl Nuclear Power Plant Cooling Pond

    International Nuclear Information System (INIS)

    Radiation exposure of the biota in the shoreline area of the Chernobyl Nuclear Power Plant Cooling Pond was assessed to evaluate radiological consequences from the decommissioning of the Cooling Pond. The article addresses studies of radioactive contamination of the terrestrial faunal complex and radionuclide concentration ratios in bodies of small birds, small mammals, amphibians, and reptiles living in the area. The data were used to calculate doses to biota using the ERICA Tool software. Doses from 90Sr and 137Cs were calculated using the default parameters of the ERICA Tool and were shown to be consistent with biota doses calculated from the field data. However, the ERICA dose calculations for plutonium isotopes were much higher (2-5 times for small mammals and 10-14 times for birds) than the doses calculated using the experimental data. Currently, the total doses for the terrestrial biota do not exceed maximum recommended levels. However, if the Cooling Pond is allowed to drawdown naturally and the contaminants of the bottom sediments are exposed and enter the biological cycle, the calculated doses to biota may exceed the maximum recommended values. The study is important in establishing the current exposure conditions such that a baseline exists from which changes can be documented following the lowering of the reservoir water. Additionally, the study provided useful radioecological data on biota concentration ratios for some species that are poorly represented in the literature.

  3. RADIATION DOSE ASSESSMENT FOR THE BIOTA OF TERRESTRIAL ECOSYSTEMS IN THE SHORELINE ZONE OF THE CHERNOBYL NUCLEAR POWER PLANT COOLING POND

    Energy Technology Data Exchange (ETDEWEB)

    Farfan, E.; Jannik, T.

    2011-10-01

    Radiation exposure of the biota in the shoreline area of the Chernobyl Nuclear Power Plant Cooling Pond was assessed to evaluate radiological consequences from the decommissioning of the Cooling Pond. The article addresses studies of radioactive contamination of the terrestrial faunal complex and radionuclide concentration ratios in bodies of small birds, small mammals, amphibians, and reptiles living in the area. The data were used to calculate doses to biota using the ERICA Tool software. Doses from {sup 90}Sr and {sup 137}Cs were calculated using the default parameters of the ERICA Tool and were shown to be consistent with biota doses calculated from the field data. However, the ERICA dose calculations for plutonium isotopes were much higher (2-5 times for small mammals and 10-14 times for birds) than the doses calculated using the experimental data. Currently, the total doses for the terrestrial biota do not exceed maximum recommended levels. However, if the Cooling Pond is allowed to drawdown naturally and the contaminants of the bottom sediments are exposed and enter the biological cycle, the calculated doses to biota may exceed the maximum recommended values. The study is important in establishing the current exposure conditions such that a baseline exists from which changes can be documented following the lowering of the reservoir water. Additionally, the study provided useful radioecological data on biota concentration ratios for some species that are poorly represented in the literature.

  4. Survival strategies of freshwater insects in cold environments

    Directory of Open Access Journals (Sweden)

    Valeria LENCIONI

    2004-09-01

    Full Text Available At high latitudes and altitudes, ice formation is a major variable affecting survival of freshwater fauna and hence the abundance and composition of invertebrate communities. Freezing, but also desiccation and anoxia, are lethal threats to all life stages of aquatic insects, from the eggs to the adults. During cold periods, the aquatic stages commonly remain in or move to a portion of the water body that will not freeze or dry (e.g., deep waters of lakes, springs and hyporheic zone where they can remain active. Less frequently they migrate to habitats that will freeze at the onset of winter. Insects have developed a complex of strategies to survive at their physiological temperature minimum, comprising (a morphological (melanism, reduction in size, hairiness/pubescence, brachyptery and aptery, (b behavioural (basking in the sun, changes in feeding and mating habit, parthenogenesis, polyploidy, ovoviviparity, habitat selection and cocoon building, (c ecological (extension of development to several years by quiescence or diapause and reduction of the number of generations per year, (d physiological and biochemical (freezing tolerance and freezing avoidance adaptations. Most species develop a combination of these survival strategies that can be different in the aquatic and terrestrial phase. Freezing avoidance and freezing tolerance may be accompanied by diapause. Both cold hardiness and diapause manifest during the unfavourable season and: (i involve storage of food resources (commonly glycogen and lipids; (ii are under hormonal control (ecdysone and juvenile hormone; (iii involve a depression or suppression of the oxidative metabolism with mitochondrial degradation. However, where the growing season is reduced to a few weeks, insects may develop cold hardiness without entering diapause, maintaining in the haemolymph a high concentration of Thermal Hysteris Proteins (THPs for the entire year and a slow but continuous growth. A synthesis of

  5. FRESHWATER FISHERY OF THE REPUBLIC OF CROATIA

    Directory of Open Access Journals (Sweden)

    Zlatko Homen

    1999-09-01

    Full Text Available As fishery, including freshwater, is very important for economy of the Republic of Croatia, the aim of this paper is to show its condition from 1995 to 1998. and also to draw a plan for fish production in 1999. The period from 1998-1999. is more stressed in order to have a total and detailed view into the present condition of the freshwater fishery and into the direction in wish that production is going. Data about carp ponds and also about trout ponds is presented. Twentynine fish-ponds are processed out of which 20 are carp ponds and 9 trout ponds. Data was delivered to the Ministry of Agriculture and Forestry Fisheries Directorate. An assessment of the condition is made for 3 fish-ponds as the desired data was not provided. As to the number of employees on fish-ponds, a slight decline could be percived in the period from 1995 to 1997. In 1998 a number of employees considerably increased for 10.07% in relation to 1997. qualification of the employees in 1998. show that the most of them are unqualified what is in accord with the requirements of a job on a fish-pond. Overall surface of the carp ponds in 1998 was 12,708 and the production surface was 9,782 ha. The most of the fish-ponds have up to 500 ha of total surface (45.45%, while 50% of the fish-ponds have production surface from 500-100 ha. The production in the trout ponds is made on 165,905 m 2 of the overall surface of the ponds, and only 40,538 m 2 are the production surface of the ponds. The production of fish in that period was in constant increase and that increasing trend in expected in 1999, and it will be an 28.30 % increase in relation to 1998. The increase is expected for all kids of fish except for big head carps, silver carps and tinch fishs. As a part of the production of tinch fishs an increase in production of consumption tinch fish is expected, but a decrease in production of one-year and two-year old fishs and two-year old fish. Out of all kinds of fish, the most produced

  6. Molecular toxicity of cerium oxide nanoparticles to the freshwater alga Chlamydomonas reinhardtii is associated with supra-environmental exposure concentrations.

    Science.gov (United States)

    Taylor, Nadine S; Merrifield, Ruth; Williams, Tim D; Chipman, J Kevin; Lead, Jamie R; Viant, Mark R

    2016-01-01

    Ceria nanoparticles (NPs) are widely used as fuel catalysts and consequently are likely to enter the environment. Their potential impacts on. biota at environmentally relevant concentrations, including uptake and toxicity, remain to be elucidated and quantitative data on which to assess risk are sparse. Therefore, a definitive assessment of the molecular and phenotypic effects of ceria NPs was undertaken, using well-characterised mono-dispersed NPs as their toxicity is likely to be higher, enabling a conservative hazard assessment. Unbiased transcriptomics and metabolomics approaches were used to investigate the potential toxicity of tightly constrained 4-5 nm ceria NPs to the unicellular green alga, Chlamydomonas reinhardtii, a sentinel freshwater species. A wide range of exposure concentrations were investigated from predicted environmental levels, to support hazard assessment, to supra-environmental levels to provide insight into molecular toxicity pathways. Ceria NPs were internalised into intracellular vesicles within C. reinhardtii, yet caused no significant effect on algal growth at any exposure concentration. Molecular perturbations were only detected at supra-environmental ceria NP-concentrations, primarily down-regulation of photosynthesis and carbon fixation with associated effects on energy metabolism. For acute exposures to small mono-dispersed particles, it can be concluded there should be little concern regarding their dispersal into the environment for this trophic level.

  7. Climate warming reduces fish production and benthic habitat in Lake Tanganyika, one of the most biodiverse freshwater ecosystems

    Science.gov (United States)

    Cohen, Andrew S.; Gergurich, Elizabeth L.; Kraemer, Benjamin M.; McGlue, Michael M.; McIntyre, Peter B.; Russell, James M.; Simmons, Jack D.; Swarzenski, Peter W.

    2016-01-01

    Warming climates are rapidly transforming lake ecosystems worldwide, but the breadth of changes in tropical lakes is poorly documented. Sustainable management of freshwater fisheries and biodiversity requires accounting for historical and ongoing stressors such as climate change and harvest intensity. This is problematic in tropical Africa, where records of ecosystem change are limited and local populations rely heavily on lakes for nutrition. Here, using a ∼1,500-y paleoecological record, we show that declines in fishery species and endemic molluscs began well before commercial fishing in Lake Tanganyika, Africa’s deepest and oldest lake. Paleoclimate and instrumental records demonstrate sustained warming in this lake during the last ∼150 y, which affects biota by strengthening and shallowing stratification of the water column. Reductions in lake mixing have depressed algal production and shrunk the oxygenated benthic habitat by 38% in our study areas, yielding fish and mollusc declines. Late-20th century fish fossil abundances at two of three sites were lower than at any other time in the last millennium and fell in concert with reduced diatom abundance and warming water. A negative correlation between lake temperature and fish and mollusc fossils over the last ∼500 y indicates that climate warming and intensifying stratification have almost certainly reduced potential fishery production, helping to explain ongoing declines in fish catches. Long-term declines of both benthic and pelagic species underscore the urgency of strategic efforts to sustain Lake Tanganyika’s extraordinary biodiversity and ecosystem services.

  8. Climate warming reduces fish production and benthic habitat in Lake Tanganyika, one of the most biodiverse freshwater ecosystems.

    Science.gov (United States)

    Cohen, Andrew S; Gergurich, Elizabeth L; Kraemer, Benjamin M; McGlue, Michael M; McIntyre, Peter B; Russell, James M; Simmons, Jack D; Swarzenski, Peter W

    2016-08-23

    Warming climates are rapidly transforming lake ecosystems worldwide, but the breadth of changes in tropical lakes is poorly documented. Sustainable management of freshwater fisheries and biodiversity requires accounting for historical and ongoing stressors such as climate change and harvest intensity. This is problematic in tropical Africa, where records of ecosystem change are limited and local populations rely heavily on lakes for nutrition. Here, using a ∼1,500-y paleoecological record, we show that declines in fishery species and endemic molluscs began well before commercial fishing in Lake Tanganyika, Africa's deepest and oldest lake. Paleoclimate and instrumental records demonstrate sustained warming in this lake during the last ∼150 y, which affects biota by strengthening and shallowing stratification of the water column. Reductions in lake mixing have depressed algal production and shrunk the oxygenated benthic habitat by 38% in our study areas, yielding fish and mollusc declines. Late-20th century fish fossil abundances at two of three sites were lower than at any other time in the last millennium and fell in concert with reduced diatom abundance and warming water. A negative correlation between lake temperature and fish and mollusc fossils over the last ∼500 y indicates that climate warming and intensifying stratification have almost certainly reduced potential fishery production, helping to explain ongoing declines in fish catches. Long-term declines of both benthic and pelagic species underscore the urgency of strategic efforts to sustain Lake Tanganyika's extraordinary biodiversity and ecosystem services. PMID:27503877

  9. Climate warming reduces fish production and benthic habitat in Lake Tanganyika, one of the most biodiverse freshwater ecosystems.

    Science.gov (United States)

    Cohen, Andrew S; Gergurich, Elizabeth L; Kraemer, Benjamin M; McGlue, Michael M; McIntyre, Peter B; Russell, James M; Simmons, Jack D; Swarzenski, Peter W

    2016-08-23

    Warming climates are rapidly transforming lake ecosystems worldwide, but the breadth of changes in tropical lakes is poorly documented. Sustainable management of freshwater fisheries and biodiversity requires accounting for historical and ongoing stressors such as climate change and harvest intensity. This is problematic in tropical Africa, where records of ecosystem change are limited and local populations rely heavily on lakes for nutrition. Here, using a ∼1,500-y paleoecological record, we show that declines in fishery species and endemic molluscs began well before commercial fishing in Lake Tanganyika, Africa's deepest and oldest lake. Paleoclimate and instrumental records demonstrate sustained warming in this lake during the last ∼150 y, which affects biota by strengthening and shallowing stratification of the water column. Reductions in lake mixing have depressed algal production and shrunk the oxygenated benthic habitat by 38% in our study areas, yielding fish and mollusc declines. Late-20th century fish fossil abundances at two of three sites were lower than at any other time in the last millennium and fell in concert with reduced diatom abundance and warming water. A negative correlation between lake temperature and fish and mollusc fossils over the last ∼500 y indicates that climate warming and intensifying stratification have almost certainly reduced potential fishery production, helping to explain ongoing declines in fish catches. Long-term declines of both benthic and pelagic species underscore the urgency of strategic efforts to sustain Lake Tanganyika's extraordinary biodiversity and ecosystem services.

  10. Immunotoxic potential of aeration lagoon effluents for the treatment of domestic and hospital wastewaters in the freshwater mussel Elliptio complanata.

    Science.gov (United States)

    Gagné, Francois; André, Chantale; Fortier, Marlène; Fournier, Michel

    2012-01-01

    Municipal wastewaters are major sources of pollution for the aquatic biota. The purpose of this study was to determine the levels of some pharmaceutical products and the immunotoxic potential of a municipal wastewater aeration lagoon for the treatment of the domestic wastewaters of a small town with wastewater inputs from a 400-bed hospital complex. Endemic mussels were collected, caged and placed in the final aeration lagoon and at sites 1 km upstream and 1 km downstream of the effluent outfall in the receiving river for a period of 14 days. The results showed that the final aeration lagoon contained high levels of total coliforms, conductivity and low dissolved oxygen (2.9 mg/L) as well as detectable amounts of trimethoprim, carbamazepine, gemfibrozil, and norfloxacin at concentrations exceeding 50 ng/L. The lagoon effluent was indeed toxic to the mussel specimens, as evidenced by the appearance of mortality after 14 days (10% mortality), decreased mussel weight-to-shell-length ratio and loss of hemocyte viability. The number of adhering hemocytes, phagocytic activity, total nitrite levels and arachidonic cyclooxygenase activity were significantly higher in mussels placed in the final aeration lagoon. A multivariate analysis also revealed that water pH, conductivity, total coliforms and dissolved oxygen were the endpoints most closely linked with phagocytic activity, the amount of adhering hemocytes and loss of hemocyte viability. In conclusion, exposure of mussels to treated aerated lagoon wastewater is deleterious to freshwater mussels where the immune system is compromised. PMID:22893952

  11. Community structure and decadal changes in macrozoobenthic assemblages in Lake Poyang, the largest freshwater lake in China

    Directory of Open Access Journals (Sweden)

    Cai Y. J.

    2014-01-01

    Full Text Available Lake Poyang is the largest freshwater lake in China and contains unique and diverse biota within the Yangtze floodplain ecosystem. However, knowledge of its macrozoobenthic assemblages remains inadequate. To characterize the current community structure of these assemblages and to portray their decadal changes, quarterly investigations were conducted at 15 sites from February to November 2012. A total of 42 taxa were recorded, and Corbicula fluminea, Limnoperna fortunei, Gammaridae sp., Nephtys polybranchia, Polypedilum scalaenum and Branchiura sowerbyi were found to dominate the community in terms of abundance. The bivalves Corbicula fluminea, Lamprotula rochechouarti, Arconaia lanceolata and Lamprotula caveata dominated the community in biomass due to their large body size. The mean abundance of the total macrozoobenthos varied from 48 to 920 ind·m-2, the mean biomass ranged from 28 to 428 g·m-2. The substrate type affected strongly the abundance, biomass, and diversity of the macrozoobenthos, with muddy sand substrates showing the highest values. Compared with historical data, remarkable changes were observed in the abundance of macrozoobenthos and the identity of the dominant species. The mean total abundance decreased from 724 ind·m-2 in 1992 to 228 ind·m-2 in 2012. The dominant species have shifted dramatically. Large unionids were dominant before 1998, whereas pollution-tolerant species (e.g., Branchiura sowerbyi increased in dominance after 2008. Our findings should have implications for the conservation of the benthic biodiversity of this large Yangtze-connected lake.

  12. Accounting for the dissociating properties of organic chemicals in LCIA: An uncertainty analysis applied to micropollutants in the assessment of freshwater ecotoxicity

    Energy Technology Data Exchange (ETDEWEB)

    Morais, Sérgio Alberto, E-mail: sergioalberto.cruzmonteiro@uab.cat [SosteniPrA (UAB-IRTA-Inèdit), Institut de Ciència i Tecnologia Ambientals (ICTA), Universitat Autònoma de Barcelona - UAB, 08193 Bellaterra, Barcelona (Spain); REQUIMTE, Instituto Superior de Engenharia do Porto, Instituto Politécnico do Porto, Rua Dr. António Bernardino de Almeida, 4200-072 Porto (Portugal); Delerue-Matos, Cristina [REQUIMTE, Instituto Superior de Engenharia do Porto, Instituto Politécnico do Porto, Rua Dr. António Bernardino de Almeida, 4200-072 Porto (Portugal); Gabarrell, Xavier [SosteniPrA (UAB-IRTA-Inèdit), Institut de Ciència i Tecnologia Ambientals (ICTA), Universitat Autònoma de Barcelona - UAB, 08193 Bellaterra, Barcelona (Spain); Departament d’Enginyeria Química, Escola d’Enginyeria, Universitat Autònoma de Barcelona - UAB, 08193 Bellaterra, Barcelona (Spain)

    2013-03-15

    Highlights: ► Fate parameters of dissociating chemicals were estimated and applied to an LCIA model. ► Results were compared to the default model using non-polar partitioning regressions. ► Negligible differences were estimated for direct emissions to freshwater. ► Results were overestimated in the default model for indirect emissions. ► Sorption of the cationic fraction of organic bases was the most influential parameter. -- Abstract: In life cycle impact assessment (LCIA) models, the sorption of the ionic fraction of dissociating organic chemicals is not adequately modeled because conventional non-polar partitioning models are applied. Therefore, high uncertainties are expected when modeling the mobility, as well as the bioavailability for uptake by exposed biota and degradation, of dissociating organic chemicals. Alternative regressions that account for the ionized fraction of a molecule to estimate fate parameters were applied to the USEtox model. The most sensitive model parameters in the estimation of ecotoxicological characterization factors (CFs) of micropollutants were evaluated by Monte Carlo analysis in both the default USEtox model and the alternative approach. Negligible differences of CFs values and 95% confidence limits between the two approaches were estimated for direct emissions to the freshwater compartment; however the default USEtox model overestimates CFs and the 95% confidence limits of basic compounds up to three orders and four orders of magnitude, respectively, relatively to the alternative approach for emissions to the agricultural soil compartment. For three emission scenarios, LCIA results show that the default USEtox model overestimates freshwater ecotoxicity impacts for the emission scenarios to agricultural soil by one order of magnitude, and larger confidence limits were estimated, relatively to the alternative approach.

  13. Potential Risks of Freshwater Aquifer Contamination with Geosequestration

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, Robert

    2013-09-30

    Substantial leakage of CO{sub 2} from deep geological strata to shallow potable aquifers is likely to be rare, but chemical detection of potential leakage nonetheless remains an integral component of any safe carbon capture and storage system. CO{sub 2} that infiltrates an unconfined freshwater aquifer will have an immediate impact on water chemistry by lowering pH in most cases and by altering the concentration of total dissolved solids. Chemical signatures in affected waters provide an important opportunity for early detection of leaks. In the presence of CO{sub 2}, trace elements such as Mn, Fe, and Ca can increase by an order of magnitude or more above control concentrations within 100 days. Therefore, these and other elements should be monitored along with pH as geochemical markers of potential CO{sub 2} leaks. Dissolved inorganic carbon and alkalinity can also be rapidly responsive to CO{sub 2} and are stable indicators of a leak. Importantly, such changes may be detectable long before direct changes in CO{sub 2} are observed. The experimental results also suggest that the relative severity of the impact of leaks on overlying drinking-water aquifers should be considered in the selection of CO{sub 2} sequestration sites. One primary selection criteria should be metal and metalloid availability, such as uranium and arsenic abundance, to carefully monitor chemical species that could trigger changes above maximum contaminant levels (MCLs). Overall, the risks of leakage from underground CO{sub 2} storage are real but appear to be manageable if systems are closely monitored.

  14. A new numerical benchmark of a freshwater lens

    Science.gov (United States)

    Stoeckl, L.; Walther, M.; Graf, T.

    2016-04-01

    A numerical benchmark for 2-D variable-density flow and solute transport in a freshwater lens is presented. The benchmark is based on results of laboratory experiments conducted by Stoeckl and Houben (2012) using a sand tank on the meter scale. This benchmark describes the formation and degradation of a freshwater lens over time as it can be found under real-world islands. An error analysis gave the appropriate spatial and temporal discretization of 1 mm and 8.64 s, respectively. The calibrated parameter set was obtained using the parameter estimation tool PEST. Comparing density-coupled and density-uncoupled results showed that the freshwater-saltwater interface position is strongly dependent on density differences. A benchmark that adequately represents saltwater intrusion and that includes realistic features of coastal aquifers or freshwater lenses was lacking. This new benchmark was thus developed and is demonstrated to be suitable to test variable-density groundwater models applied to saltwater intrusion investigations.

  15. Bibliography on cycling of trace metals in freshwater ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    LaRiviere, M.G.; Scott, A.J.; Woodfield, W.G.; Cushing, C.E.

    1978-07-01

    This bibliography is a listing of pertinent literature directly addressing the cycling of trace metals in freshwater ecosystems. Data on cycling, including the influences of environmental mediators, are included. 151 references.

  16. Bibliography on cycling of trace metals in freshwater ecosystems

    International Nuclear Information System (INIS)

    This bibliography is a listing of pertinent literature directly addressing the cycling of trace metals in freshwater ecosystems. Data on cycling, including the influences of environmental mediators, are included. 151 references

  17. Freshwater mussels of the Noxubee National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This is a summary of the freshwater mussels on Noxubee National Wildlife Refuge. The species listed and assoicated informaiton is based on existing literature. The...

  18. Caernarvon freshwater diversion: Contaminants monitoring study (interim report)

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Caernarvon Freshwater Diversion Structure was completed in January 1991 by the U.S. Army Corps of Engineers. The purpose of the structure is to divert...

  19. Imperiled Freshwater and Diadromous Fishes of North America

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — List of imperiled freshwater and diadromous fishes of North America as determined by the 2008 American Fisheries Society (AFS) Endangered Species Committee (ESC) on...

  20. Freshwater mussels of North Mississippi National Wildlife Refuge Complex

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — A literature search of the distribution of freshwater mussels anticipated to be found on refuges assoicated with the North Mississippi Refuges Cjomplex and museum...

  1. Extinction rates in North American freshwater fishes, 1900-2010

    Science.gov (United States)

    Burkhead, Noel M.

    2012-01-01

    Widespread evidence shows that the modern rates of extinction in many plants and animals exceed background rates in the fossil record. In the present article, I investigate this issue with regard to North American freshwater fishes. From 1898 to 2006, 57 taxa became extinct, and three distinct populations were extirpated from the continent. Since 1989, the numbers of extinct North American fishes have increased by 25%. From the end of the nineteenth century to the present, modern extinctions varied by decade but significantly increased after 1950 (post-1950s mean = 7.5 extinct taxa per decade). In the twentieth century, freshwater fishes had the highest extinction rate worldwide among vertebrates. The modern extinction rate for North American freshwater fishes is conservatively estimated to be 877 times greater than the background extinction rate for freshwater fishes (one extinction every 3 million years). Reasonable estimates project that future increases in extinctions will range from 53 to 86 species by 2050.

  2. [Latin American malacology. Freshwater mollusks from Argentina].

    Science.gov (United States)

    Rumi, Alejandra; Gregoric, Diego E Gutiérrez; Núñez, Verónica; Darrigran, Gustavo A

    2008-03-01

    A report and an updated list with comments on the species of freshwater molluscs of Argentina which covers an area of 2 777 815 km2 is presented. Distributions of Gastropoda and Bivalvia families, endemic, exotic, invasive as well as entities of sanitary importance are also studied and recommendations on their conservation are provided. Molluscs related to the Del Plata Basin have been thoroughly studied in comparison to others areas of the country. This fauna exhibits relatively the biggest specific richness and keeps its affinity with the fauna of other regions of the basin in areas of Paraguay and Brasil. The 4 500 records of molluscs considered in this paper arise from the study of the collections of Museo Argentino de Ciencias Naturales "Bernardino Rivadavia", Buenos Aires; Museo de La Plata, La Plata and Fundación "Miguel Lillo", Tucumán. These institutions keep very important collections of molluscs in southern South America. Field information has recently been obtained and localities cited by other authors are also included in the data base. Until today, 166 species have been described, 101 belonging to 10 families of Gastropoda and 65 to 7 of Bivalvia. Families with highest specific richness are Lithoglyphidae (22) and Sphaeriidae (25), respectively. The number of endemic species (those present only in Argentina) by family is: Gastropoda: Ampullariidae (1), Cochliopidae (10), Lithoglyphidae (11), Thiariidae (3), Chilinidae (11), Lymnaeidae (2) and Physidae (2?); Bivalvia: Hyriidae (1?); Etheriidae (1?) and Sphaeriidae (10). Families with a distribution that comprise almost the whole country are: the Sphaeriidae and the gastropods Cochliopidae, Chilinidae and Lymnaeidae. Families Erodonidae and Solecurtidae (Bivalvia) were registered in mixohaline environments from Buenos Aires province. Gastropod families Thiaridae and Glacidorbiidae show a very restricted distribution. The rest of the families are present mainly in the center and north of the country

  3. Freshwater aquaculture in the United States: Complying with environmental protection law and policy

    OpenAIRE

    Noble, M.

    1993-01-01

    The author deal with the relations between the freshwater fish culture and the many regulations of the environmental protection in USA. The author develops the federal and state administrative frameworks (federal government administration of aquaculture, the state government administration of aquaculture), the freshwater aquaculture and water rights, the freshwater aquaculture and wetlands regulation, the freshwater aquaculture and water quality regulation, the freshwater aquaculture and wild...

  4. SILENT WITNESS OF WATER POLLUTION: BIOINDICATOR FRESHWATER INVERTEBRATES

    OpenAIRE

    ARSLAN, Naime; Kara, Deniz; ODABAŞI, Deniz Anıl

    2015-01-01

    During the last years, not only industrial activities, but also anthropogenic activities have had negative consequences for the freshwater ecosystems. All aquatic organisms accumulate organic or inorganic elements in their bodies whether or not these elements are essential to metabolism. Community compositions of freshwater invertebrates such as gastropods, oligochaetes and chironomids, reflect the states and changes in aquatic ecosystems. Many factors regulate the occurrence and distribution...

  5. Nucleus Pearl Coating Process of Freshwater Mussel Anodonta woodiana (Unionidae)

    OpenAIRE

    WASMEN MANALU; DEDY DURYADI SOLIHIN; SATA YOSHIDA SRIE RAHAYU; RIDWAN AFFANDI

    2013-01-01

    The limiting factor which is a weakness of sea water pearl production are high costs, the risk of major business failures and a long coating time. From the issue of freshwater pearls appear to have prospects of alternative substitution for sea water pearl. This present study aimed to evaluate effect of loads (the number and diameter nucleus) on freshwater pearl coating process and the number and size of the appropriate nucleus diameter, to produce the optimum coating thickness of half-round p...

  6. Richness and endemism of the freshwater fishes of Mexico

    OpenAIRE

    T. Contreras-MacBeath; M. B. Rodríguez; Sorani, V.; Goldspink, C.; G. McGregor Reid

    2014-01-01

    A study of richness and endemism of the freshwater fishes of Mexico, was carried out in order to identify hotspots and inform conservation efforts. This was done by mapping and overlaying individual species distributions by means of geographical information systems based on museum data. The study was able to confirm several previously proposed centres of freshwater fish richness (Southeastern Mexico, the Mesa Central, the Bravo-Conchos river system and the Panuco and Tuxpan-Nautla rivers). Se...

  7. Restricted-range fishes and the conservation of Brazilian freshwaters.

    Directory of Open Access Journals (Sweden)

    Cristiano Nogueira

    Full Text Available BACKGROUND: Freshwaters are the most threatened ecosystems on earth. Although recent assessments provide data on global priority regions for freshwater conservation, local scale priorities remain unknown. Refining the scale of global biodiversity assessments (both at terrestrial and freshwater realms and translating these into conservation priorities on the ground remains a major challenge to biodiversity science, and depends directly on species occurrence data of high taxonomic and geographic resolution. Brazil harbors the richest freshwater ichthyofauna in the world, but knowledge on endemic areas and conservation in Brazilian rivers is still scarce. METHODOLOGY/PRINCIPAL FINDINGS: Using data on environmental threats and revised species distribution data we detect and delineate 540 small watershed areas harboring 819 restricted-range fishes in Brazil. Many of these areas are already highly threatened, as 159 (29% watersheds have lost more than 70% of their original vegetation cover, and only 141 (26% show significant overlap with formally protected areas or indigenous lands. We detected 220 (40% critical watersheds overlapping hydroelectric dams or showing both poor formal protection and widespread habitat loss; these sites harbor 344 endemic fish species that may face extinction if no conservation action is in place in the near future. CONCLUSIONS/SIGNIFICANCE: We provide the first analysis of site-scale conservation priorities in the richest freshwater ecosystems of the globe. Our results corroborate the hypothesis that freshwater biodiversity has been neglected in former conservation assessments. The study provides a simple and straightforward method for detecting freshwater priority areas based on endemism and threat, and represents a starting point for integrating freshwater and terrestrial conservation in representative and biogeographically consistent site-scale conservation strategies, that may be scaled-up following naturally linked

  8. UAV-based hyperspectral monitoring of small freshwater area

    Science.gov (United States)

    Pölönen, I.; Puupponen, H.-H.; Honkavaara, Eija; Lindfors, A.; Saari, H.; Markelin, L.; Hakala, T.; Nurminen, K.

    2014-10-01

    Recent development in compact, lightweight hyperspectral imagers have enabled UAV-based remote sensing with reasonable costs. We used small hyperspectral imager based on Fabry-Perot interferometer for monitoring small freshwater area in southern Finland. In this study we shortly describe the utilized technology and the field studies performed. We explain processing pipeline for gathered spectral data and introduce target detection-based algorithm for estimating levels of algae, aquatic chlorophyll and turbidity in freshwater. Certain challenges we faced are pointed out.

  9. New data on freshwater psammic Gastrotricha from Brazil

    OpenAIRE

    André Rinaldo Garraffoni; Thiago Araujo; Anete Lourenço; Maria Balsamo

    2010-01-01

    Current knowledge of freshwater gastrotrich fauna from Brazil is underestimated as only two studies are available. The present communication is a taxonomic account of the first-ever survey of freshwater Gastrotricha in Minas Gerais State. Samplings were carried out yielding six species of three Chaetonotidae genera: Aspidiophorus cf. pleustonicus, Ichthydium cf. chaetiferum, Chaetonotus acanthocephalus, C. heideri, C. cf. succinctus, Chaetonotus sp., and also an undescribed species belonging ...

  10. New data on freshwater psammic Gastrotricha from Brazil

    OpenAIRE

    André R. S. Garraffoni; Araujo, Thiago Q.; Lourenço, Anete P.; Balsamo, Maria

    2010-01-01

    Abstract Current knowledge of freshwater gastrotrich fauna from Brazil is underestimated as only two studies are available. The present communication is a taxonomic account of the first-ever survey of freshwater Gastrotricha in Minas Gerais State. Samplings were carried out yielding six species of three Chaetonotidae genera: Aspidiophorus cf. pleustonicus, Ichthydium cf. chaetiferum, Chaetonotus acanthocephalus, Chaetonotus heideri, Chaetonotus cf. succinctus, Chaetonotus sp., and also an und...

  11. Cyanobacterial biodiversity from different freshwater ponds of Thanjavur, Tamilnadu (India)

    OpenAIRE

    Muthukumar, Chinnasamy; Muralitharan, Gangatharan; Vijayakumar, Ramasamy; Panneerselvam, Annamalai; Thajuddin, Nooruddin

    2007-01-01

    Cyanobacterial biodiversity from different freshwater ponds of Thanjavur, Tamilnadu (India). Studies on the cyanobacterial biodiversity of 5 different freshwater ponds in and around Thanjavur, Tamilnadu during summer month (June, 2004) has been made and compared their variations among five different ponds. In addition, certain physico-chemical parameters of pond waters such as dissolved oxygen, net productivity, pH, carbonate, bicarbonate, nitrate, nitrite, total phosphorus, inorganic phospho...

  12. Water rules all processes in tidal freshwater wetlands

    OpenAIRE

    Barendregt, A.

    2012-01-01

    Three essential factors cause the presence of tidal freshwater wetlands (TFW). First, it is a freshwater ecosystem located in the upper part of the estuary, where permanent input of river water creates fresh conditions constantly. Second, there is a tidal pulse that causes very dynamic conditions in current, flooding, redistribution of sediments and morphology. Moreover, it is a wetland with permanently reduced condition in the soil. Third, because the river is the sink of the uplands, this e...

  13. Freshwater Microcosms-Based Assessment of Eco-toxicological Effects of a Chemical Effluent from the Pilcam Industry in Cameroon

    Directory of Open Access Journals (Sweden)

    J. E. Djomo

    2004-09-01

    Full Text Available We studied the acute toxicity of a raw effluent from a battery manufacturing plant (Pilcam in Douala, Cameroon, to a freshwater fish (Oreochromis niloticus, and subsequently evaluated its sub-acute effects on water quality and the biota in freshwater microscosms. The acute toxicity test was based on 96 hrs static renewal bioassays that resulted in 96-h LC50 and LC90 values of 16 and 20.7% (v/v, respectively. The sub-acute experiments were conducted by exposing several species of aquatic organisms (plankton, macro-invertebrates and mollusks to lower effluent concentrations [1.6%, 8.0%, 16% (v/v] for six weeks, and monitoring their survival rates, as well as the physical and chemical characteristics of water. These concentrations were based on 10%, 50%, and 100% of the 96 h - median lethal concentrations (LC50 of the effluent to the freshwater fish, Oreochromis niloticus. Significant effects on functional parameters, such as, chlorophyll-a and total protein could not be demonstrated. However, the activity of alkaline phosphatase was significantly inhibited at all concentrations tested. Phytoplankton, zooplankton, macro-invertebrate communities and snails were negatively affected by the effluent application at concentrations ≥ 8% (v/v, with chlorophyta, ciliates, ostracoda, annelida, planaria and snails being the most sensitive groups. The snails were eliminated after 24 h exposure from microcosms treated with effluent at concentration ≥ 8% (v/v. Effluent exposure also caused significant effects on water quality parameters (DO, pH, hardness, conductivity, color, turbidity, ammonia in general at concentrations ≥ 8% (v/v. Temperature and alkalinity were not significantly affected. Overall, data from this research indicate that a dilution of the Pilcam effluent down to 1.6% does not provide protection against chronic toxicity to aquatic organisms. Further studies are needed to determine the no observable adverse

  14. Geochemistry, biota and natural background levels in an arsenic naturally contaminated volcanic aquifer

    Science.gov (United States)

    Preziosi, Elisabetta; Amalfitano, Stefano; Di Lorenzo, Tiziana; Parrone, Daniele; Rossi, David; Ghergo, Stefano; Lungarini, Silvia; Zoppini, Anna Maria

    2015-04-01

    The tight links between chemical and ecological status are largely acknowledged as for surface water bodies, while aquifers are still considered as hidden groundwater reservoirs, rather than ecosystems to be preserved. Geochemical and biological interactions play a key role in all subterranean processes, including the dynamics of the fate of anthropogenic contaminants. Studies on groundwater dependent ecosystems (GDE) were mainly focused on karst aquifers so far, but an increased awareness on the importance of water-rock interactions and methodological improvements in microbial ecology are rapidly increasing the level of characterization of groundwater ecosystems in various hydrogeological contexts. Similarly, knowledge about groundwater biodiversity is still limited, especially if porous habitats are concerned. Yet, groundwater and GDEs are populated by a diverse and highly adapted biota, dominated by crustaceans, which provide important ecosystem services and act as biological indicators of chemical and quantitative impact on groundwater resources. In a previous research (Amalfitano et al. 2014), we reported that the microbial community heterogeneity may reflect the lithological and hydrogeological complexity within volcanic and alluvial facies transition in a groundwater body. The quantitative tracking of the microbial community structure allowed disentangling the natural biogeochemical processes evolving within the aquifer flow path. The analyses of groundwater crustaceans assemblages may contribute to shed more light upon the state and dynamics of such ecosystems. In the present research, a comprehensive study of a water table aquifer flowing through a quaternary volcanic district is being performed, including the geochemical (inorganic) composition, the microbial composition, and the analysis of crustacean assemblages . Groundwater samples are periodically collected from private wells and springs under a low anthropic impact. The key issues within the

  15. High levels of natural radioactivity in biota from deep sea hydrothermal vents

    International Nuclear Information System (INIS)

    Hydrothermal vent ecosystems are associated with areas of tectonic activities throughout the deep sea and are thus enriched in natural primitive radionuclides characterizing the magma source i.e. uranium-thorium series. However, the amount of data on radionuclide content in hydrothermal vent biota is very scarce. Here we present data from various archived biological samples collected on several hydrothermal vent site. Samples were collected by manned or unmanned submersibles on the East Pacific Rise (EPR) in 1996 and 2002 and on the Mid Atlantic Ridge (MAR) in 2001. Their concentrations in uranium and thorium isotopes were determined by isotope dilution mass spectrometry. Measurements were performed with a Sector field ICP-MS, the Axiom single collector from VG Elemental (Winsford, Cheshire, UK). 210Po was determined through alpha spectrometry. Results in Table II underline that high levels in uranium isotopes are found in polychaetes from the East Pacific Rise. The highest contents characterize their tubes plus mucus samples. On the contrary, the deep-sea amphipod sample (Orchomenella) collected outside hydrothermal vent areas exhibits the lowest values though direct comparison is difficult due to variability between species. 238U contents in coastal marine organisms are generally in the range 1 to 5 Bq kg-1 dry weight. Comparison between sites (Atlantic vs Pacific) is not obvious since different species have been sampled on MAR and EPR but the highest levels characterize the samples from EPR. Some samples demonstrate 234U/238U ratios very close to the mean value for seawater (1.1 - 1.2) but four present lower ratios (i.e. one sample of Bathymodiolus, Paralvinella, Riftia and Orchomenella). This is certainly to be linked to an uptake of particulate uranium. 210Po contents are very high in polychaetes tubes and mucus and are almost entirely supported by 210Pb. This in agreement with what has been reported by Cherry et al. (1992) for polychaetes (Alvinella and

  16. Lake Michigan: Man's effects on native fish stocks and other biota

    Science.gov (United States)

    Wells, LaRue; McLain, Alberton L.

    1973-01-01

    Man's activities have caused great changes in Lake Michigan in the past 120 years. Although changes in water chemistry and lower biota have been generally modest (except locally), those in native fish stocks have been vast. Exploitation, exotic fish species, and eutrophication and other forms of pollution all have played a role in bringing about the changes (mostly declines in abundance) in fish populations. Exploitation resulted in a noticeable reduction in abundance of certain native species (especially whitefish) soon after the establishment of the commercial fishery in the 1840's. By the 1930's the sturgeon and the two largest deepwater ciscoes (Coregonus nigripinnis and C. johannae) became severely depleted. Other species- whitefish (Coregonus clupeaformis), lake trout (Salvelinus namaycush), and lake herring (C. artedii)- remained important commercially, but at a lower level of production than originally; greatly increased fishing effort and efficiency were required to maintain even these decreased catches. The catch of intermediate-size ciscoes held relatively stable, but again only through sharply increased fishing effort and efficiency. The earliest serious effects of exotic fish species on native fish stocks may have been during the 1930's, when smelt (Osmerus mordax), first became abundant. Powerful influences by exotics were not obvious, however, until the 1940's, when the sea lamprey's (Petromyzon marinus) predation on several species, particularly the lake trout, became critical. In the 1950's the sea lamprey was joined by the alewife (Alosa pseudoharengus), another exotic strongly deleterious to several native fish. The alewife apparently inhibited reproduction of deepwater ciscoes, yellow perch (Perca flavescens), deepwater sculpins (Myoxocephalus quadricornis), emerald shiners (Notropis atherinoides), and perhaps others (through competing with young, or feeding on them). At the same time, however, the alewife as a prolific forage fish has made

  17. Stormwater runoff drives viral community composition changes in inland freshwaters

    Directory of Open Access Journals (Sweden)

    Kurt E. Williamson

    2014-03-01

    Full Text Available Storm events impact freshwater microbial communities by transporting terrestrial viruses and other microbes to freshwater systems, and by potentially resuspending microbes from bottom sediments. The magnitude of these impacts on freshwater ecosystems is unknown and largely unexplored. Field studies carried out at two discrete sites in coastal Virginia (USA were used to characterize the viral load carried by runoff and to test the hypothesis that terrestrial viruses introduced through stormwater runoff change the composition of freshwater microbial communities. Field data gathered from an agricultural watershed indicated that primary runoff can contain viral densities approximating those of receiving waters. Furthermore, viruses attached to suspended colloids made up a large fraction of the total load, particularly in early stages of the storm. At a second field site (stormwater retention pond, RAPD-PCR profiling showed that the viral community of the pond changed dramatically over the course of two intense storms while relatively little change was observed over similar time scales in the absence of disturbance. Comparisons of planktonic and particle-associated viral communities revealed two completely distinct communities, suggesting that particle-associated viruses represent a potentially large and overlooked portion of aquatic viral abundance and diversity. Our findings show that stormwater runoff can quickly change the composition of freshwater microbial communities. Based on these findings, increased storms in the coastal mid-Atlantic region predicted by most climate change models will likely have important impacts on the structure and function of local freshwater microbial communities.

  18. Deep-ocean origin of the freshwater eels.

    Science.gov (United States)

    Inoue, Jun G; Miya, Masaki; Miller, Michael J; Sado, Tetsuya; Hanel, Reinhold; Hatooka, Kiyotaka; Aoyama, Jun; Minegishi, Yuki; Nishida, Mutsumi; Tsukamoto, Katsumi

    2010-06-23

    Of more than 800 species of eels of the order Anguilliformes, only freshwater eels (genus Anguilla with 16 species plus three subspecies) spend most of their lives in freshwater during their catadromous life cycle. Nevertheless, because their spawning areas are located offshore in the open ocean, they migrate back to their specific breeding places in the ocean, often located thousands of kilometres away. The evolutionary origin of such enigmatic behaviour, however, remains elusive because of the uncertain phylogenetic position of freshwater eels within the principally marine anguilliforms. Here, we show strong evidence for a deep oceanic origin of the freshwater eels, based on the phylogenetic analysis of whole mitochondrial genome sequences from 56 species representing all of the 19 anguilliform families. The freshwater eels occupy an apical position within the anguilliforms, forming a highly supported monophyletic group with various oceanic midwater eel species. Moreover, reconstruction of the growth habitats on the resulting tree unequivocally indicates an origination of the freshwater eels from the midwater of the deep ocean. This shows significant concordance with the recent collection of mature adults of the Japanese eel in the upper midwater of the Pacific, suggesting that they have retained their evolutionary origin as a behavioural trait in their spawning areas. PMID:20053660

  19. Environmental versus anthropogenic effects on population adaptive divergence in the freshwater snail Lymnaea stagnalis.

    Directory of Open Access Journals (Sweden)

    Anthony Bouétard

    Full Text Available Repeated pesticide contaminations of lentic freshwater systems located within agricultural landscapes may affect population evolution in non-target organisms, especially in species with a fully aquatic life cycle and low dispersal ability. The issue of evolutionary impact of pollutants is therefore conceptually important for ecotoxicologists. The impact of historical exposure to pesticides on genetic divergence was investigated in the freshwater gastropod Lymnaea stagnalis, using a set of 14 populations from contrasted environments in terms of pesticide and other anthropogenic pressures. The hypothesis of population adaptive divergence was tested on 11 life-history traits, using Q(ST-F(ST comparisons. Despite strong neutral differentiation (mean F(ST = 0.291, five adult traits or parameters were found to be under divergent selection. Conversely, two early expressed traits showed a pattern consistent with uniform selection or trait canalization, and four adult traits appeared to evolve neutrally. Divergent selection patterns were mostly consistent with a habitat effect, opposing pond to ditch and channel populations. Comparatively, pesticide and other human pressures had little correspondence with evolutionary patterns, despite hatching rate impairment associated with global anthropogenic pressure. Globally, analyses revealed high genetic variation both at neutral markers and fitness-related traits in a species used as model in ecotoxicology, providing empirical support for the need to account for genetic and evolutionary components of population response in ecological risk assessment.

  20. Chromium in water, suspended particles, sediments and biota in the Iraja River estuary

    Energy Technology Data Exchange (ETDEWEB)

    Pfeiffer, W.C.; Fiszman, M.; de Lacerda, L.D.; van Weerfelt, M.; Carbonell, N.

    1982-11-01

    Analyses of chromium concentrations in waters, suspended particles, bottom sediments, fish (Poecilia reticulata), plants (Paspalum vaginatum, Sesuvium portulacastrum, Philoxeros vermicularis), soils and barnacles (Balanus sp.) were performed from August 1976 to September 1980 in samples collected from the Iraja River and inside its estuary in Guanabara Bay (Rio de Janeiro, Brazil). Sediments and water from the Iraja River showed chromium concentrations of 17536 and 23.39 ppm--a thousand times higher than the published data for freshwater systems. Chromium removed from solution by bottom sediments reaches Guanabara Bay linked to particulate matter. Fish and emergent grass inside the river concentrate chromium from water and/or sediment, returning the metal to the system as detritus. Soil and plants inside the estuary concentrate chromium thirty and ten times higher than in the control area. The vegetal community exhibits a concentration factor smaller than that related to soil and prevents the return of chromium to the estuarine waters. Inside the Guanabara Bay, Balanus sp. appears to be an effective biological monitor as it concentrates chromium in soft tissues 10/sup 3/ times higher than values found in suspended particles (0.012 ..mu..g ml/sup -1/).

  1. Cyanobacteria and cyanotoxins in freshwaters of Uruguay

    Directory of Open Access Journals (Sweden)

    Sylvia Bonilla

    2015-12-01

    Full Text Available Cyanobacterial blooms are a worldwide environmental problem. This phenomenon is typically associated with eutrophication (nutrient enrichment and changes in hydrology. In this study we analysed the distribution of planktonic cyanobacteria in Uruguay and their toxins (microcystin, saxitoxin and cylindrospermopsin, working with an interagency team (OSE, DINAMA, IM, University of the Republic and IIBCE. An historical data base (n = 3061 for 64 ecosystems, years 1980-2014 was generated. Differences between lotic and lentic ecosystems were found in terms of chlorophyll a and nutrient concentrations, usually indicating eutrophication. Two geo-referenced maps for the country were generated with cyanobacteria biomass indicators and the most relevant toxin (microcystin, according to risk levels suggested by the World Health Organization for recreational waters. The areas of greatest risk of exposure were the reservoirs of large rivers (Uruguay and Río Negro and Río de la Plata beaches. In the second part of the study, up to 20 mg L-1of microcystin was quantified in bloom (scum samples, as well as the presence of genes that suggest more microcystin varieties, potentially with greater toxicity. This study provides basic information about the distribution of cyanobacteria in Uruguayan freshwaters that will be useful for national monitoring programs and scientific research.

  2. Organic environmental poisons in Norwegian freshwater fish

    International Nuclear Information System (INIS)

    According to this article, the level of organic poisons in Norwegian freshwater fish is, on the whole, is too small to threaten human health. It has been found, however, that liver from some species such as burbot, from some lakes, should not be eaten. These lakes are found to contain higher levels of PCB (polychlorinated biphenyls) and DDT (dichlorodiphenyltrichloroethane). Previously, pregnant or breast-feeding women anywhere in Norway have been advised not to eat pike, large perch or large trout because of too much mercury. Other people should not eat these species more often than once per month. In general, the level of organic environmental poisons is higher in the southern part of the country than in the northern part. The sediments of the lakes in large parts of South Norway are contaminated with lead, mercury and cadmium as compared with the conditions before the industrial revolution. However, the level of metals in the lake sediments are relatively low, and these substances are unlikely to appear in the food chain, by and large. The anthropogenic emission of lead was insignificant before the industrial revolution. The exception of lead from German mining industry in the 1700s

  3. Investigation of strength properties of freshwater ice

    Directory of Open Access Journals (Sweden)

    Bragov A.

    2015-01-01

    Full Text Available A study of the strength and deformation properties of freshwater ice under compression, tension and shear in a wide range of strain rates (10−4 − 3 ⋅ 103 s−1 and temperatures of − 5∘ C, − 20∘ C, − 40∘ C and − 60∘ C was performed. Static stress-strain curves of ice under compression were obtained on which the identified strength properties of ice as well as compressive modulus. To determine the mechanical properties of ice at high-speed loading the Kolsky method was used with various embodiments of split Hopkinson bar. The deformation curves were obtained at various loading conditions. Thereon breaking points were defined as well as their dependence on the strain rate and temperature. Also static and dynamic strength properties of ice at splitting and circular shear were defined. Increase in the dynamic strength properties upon the static ones for all loading conditions was marked.

  4. Feeding level and frequency for freshwater angelfish

    Directory of Open Access Journals (Sweden)

    Felipe de Azevedo Silva Ribeiro

    2012-06-01

    Full Text Available The objective of this study was to determine the optimal feeding level and feeding frequency for the culture of freshwater angelfish (Pterophyllum scalare. A randomized block design in a factorial scheme (3 × 2 with three feeding levels (30, 60 and 90 g/kg of body weight (BW/day and two feeding frequencies (1x and 2x/day was set up in duplicate, representing 24 experimental units. Data were analyzed using two-way ANOVA and the Tukey test for comparison between means. After 84 days, results indicated that both factors influenced fish performance. No interaction between these factors was, however, observed. Increased feeding level and feeding frequency resulted in increased feed intake. The feed conversion ratio was negatively affected by feeding level, but not affected by feeding frequency. Final weights were higher when fish were fed twice daily, at levels of 60 or 90 g/kg BW/day. Specific growth rate was higher when fish received 60 or 90 g/kg BW/day, regardless of the feeding frequency. Survival was not affected by any treatment, with mean survival rates higher than 90%. It is recommended that juveniles be fed at a level of 60 g/kg BW/day with a minimum of two meals per day, to attain optimal survival, growth and feed efficiency.

  5. Flavobacterium procerum sp. nov., isolated from freshwater.

    Science.gov (United States)

    Feng, Qingqing; Han, Lu; Yuan, Xin; Tan, Xu; Gao, Yuan; Lv, Jie

    2015-08-01

    A Gram-reaction-negative, strictly aerobic, yellow-pigmented, rod-shaped bacterium, designated strain T3T, was isolated from freshwater of Chishui River flowing through Maotai town, Guizhou, south-west China. Analysis of the16S rRNA gene sequence indicated that strain T3T was a member of the genus Flavobacterium and closely related to Flavobacterium resistens DSM 19382T (96.8 %). The novel strain was able to grow at 10-34 °C (optimum 28 °C), pH 6.0-11.0 (optimum pH 8.0-9.0) and with 0-2.0 % (w/v) NaCl (optimum 0 %). The major polar lipids were phosphatidylethanolamine, two unknown glycolipids, five unknown aminolipids and four unidentified lipids, and the major respiratory quinone was MK-6. The predominant fatty acids were C16  :  1ω7c and/or C16  :  1ω6c and iso-C15  :  0. The DNA G+C content of the strain was 36 mol  %. Based on these data, strain T3T represents a novel species of the genus Flavobacterium, for which the name Flavobacterium procerum sp. nov. is proposed. The type strain is T3T ( = CGMCC 1.12926T = JCM 30113T). PMID:25969476

  6. The International Editorship of Freshwater Systems

    Directory of Open Access Journals (Sweden)

    Karl E. Havens

    2001-01-01

    Full Text Available It is my pleasure to announce that two distinguished internationalscientists have joined the editorship of the FreshwaterSystems domain of TheScientificWorldJOURNAL — Professor BrijGopal of Jawaharlal Nehru University (India and Dr. Manual Gra柠of the Universityof Coimbra (Portugal. Professor Gopal is the Secretary General of the NationalInstitute of Ecology, Editor of the InternationalJournal of Ecology & Environmental Science,and Chairman of the SIL (International Association of Theoretical and AppliedLimnology Committee on Limnology in Developing Countries. His research interestsinclude the ecology, biogeochemistry and biodiversity of wetland ecosystems,the management of wetlands as an integral part of the watershed, and wetlandwater policy–related issues. Dr. Gra柠is a stream ecologist whose researchinterests include the two general areas of organic matter decomposition andbiological monitoring. His specific areas of research focus include quantificationof organic matter and other chemical changes in decomposing leaves, the ecologyof aquatic hyphomycetes, and the ecology of animals feeding on detritus. Hisresearch dealing with biological monitoring is carried out in close cooperationwith the paper and mining industries, facilitating the practical applicationof his work.

  7. Using growth measures in the freshwater shrimp Caridina nilotica as biomarkers of Roundup® pollution of South African freshwater systems

    Science.gov (United States)

    Mensah, P. K.; Muller, W. J.; Palmer, C. G.

    There has been global concern about the effect of toxic chemicals on aquatic biota due to the upsurge in contamination of aquatic ecosystems by these chemicals, which includes pesticides. Roundup® and other glyphosate-based herbicides are frequently used in the chemical control of weeds and invading alien plant species in South Africa. These bio-active chemicals ultimately get into water courses directly or indirectly through processes such as drifting, leaching, surface runoff and foliar spray of aquatic nuisance plants. However, there is no South African water quality guideline to protect indigenous freshwater non-target organisms from the toxic effects of glyphosate-based herbicides. This study evaluated the possible use of growth measures in Caridina nilotica as biomarkers of Roundup® pollution as part of developing glyphosate water quality guideline for the protection of aquatic life in South Africa. Using static-renewal methods in a 25-day growth toxicity test, 40 days post hatch shrimps were exposed to different sub-lethal Roundup® concentrations of 0.0 (control), 2.2, 2.8, 3.4, 4.3 and 5.4 mg/L. Shrimps were fed daily with TetraMin® flake food and test solutions changed every third day. Shrimp total lengths and wet weights were measured every fifth day. These data were used to determine the shrimp’s growth performance and feed utilization in terms of percent weight gain (PWG), percent length gain (PLG), specific growth rate (SGR), condition factor (CF), feed intake (FI), feed conversion ratio (FCR) and feed conversion efficiency (FCE). Moulting was observed for 14 days and the data used to determine the daily moult rate for each concentration. Results of growth performance and food utilization indices showed that growth was significantly impaired in all exposed groups compared to control (p < 0.05). Moulting frequency was also higher in all exposed groups than in control (p < 0.05). Although all the tested growth measures proved to be possible

  8. A combined approach of experiments and modelling for the implementation of freshwater copepods in ecological risk assessment

    OpenAIRE

    Kulkarni, Devdutt

    2014-01-01

    Standardized test guidelines used in ecological risk assessment (ERA) consider a relatively small set of test species. For instance in most standard risk assessments, Daphnia magna is the only required species representing freshwater invertebrates which assumes that tests with such standard species in combination with relatively large assessment factors are protective for other species in the field. Standard test species are usually selected based on intrinsic sensitivity as well as practicab...

  9. Interactions of grazing history, cattle removal and time since rain drive divergent short-term responses by desert biota.

    Directory of Open Access Journals (Sweden)

    Anke S K Frank

    Full Text Available Arid grasslands are used worldwide for grazing by domestic livestock, generating debate about how this pastoral enterprise may influence native desert biota. One approach to resolving this question is to experimentally reduce livestock numbers and measure the effects. However, a key challenge in doing this is that historical grazing impacts are likely to be cumulative and may therefore confound comparisons of the short-term responses of desert biota to changes in stocking levels. Arid areas are also subject to infrequent flooding rainfalls that drive productivity and dramatically alter abundances of flora and fauna. We took advantage of an opportunity to study the recent effects of a property-scale cattle removal on two properties with similarly varied grazing histories in central Australia. Following the removal of cattle in 2006 and before and after a significant rainfall event at the beginning of 2007, we sampled vegetation and small vertebrates on eight occasions until October 2008. Our results revealed significant interactions of time of survey with both grazing history and grazing removal for vascular plants, small mammals and reptiles. The mammals exhibited a three-way interaction of time, grazing history and grazing removal, thus highlighting the importance of careful sampling designs and timing for future monitoring. The strongest response to the cessation of grazing after two years was depressed reproductive output of plants in areas where cattle continued to graze. Our results confirm that neither vegetation nor small vertebrates necessarily respond immediately to the removal of livestock, but that rainfall events and cumulative grazing history are key determinants of floral and faunal performance in grassland landscapes with low and variable rainfall. We suggest that improved assessments could be made of the health of arid grazing environments if long-term monitoring were implemented to track the complex interactions that influence

  10. Filling the gaps: Predicting the distribution of temperate reef biota using high resolution biological and acoustic data

    Science.gov (United States)

    Hill, Nicole A.; Lucieer, Vanessa; Barrett, Neville S.; Anderson, Tara J.; Williams, Stefan B.

    2014-06-01

    Management of the marine environment is often hampered by a lack of comprehensive spatial information on the distribution of diversity and the bio-physical processes structuring regional ecosystems. This is particularly true in temperate reef systems beyond depths easily accessible to divers. Yet these systems harbor a diversity of sessile life that provide essential ecosystem services, sustain fisheries and, as with shallower ecosystems, are also increasingly vulnerable to anthropogenic impacts and environmental change. Here we use cutting-edge tools (Autonomous Underwater Vehicles and ship-borne acoustics) and analytical approaches (predictive modelling) to quantify and map these highly productive ecosystems. We find the occurrence of key temperate-reef biota can be explained and predicted using standard (depth) and novel (texture) surrogates derived from multibeam acoustic data, and geographic surrogates. This suggests that combinations of fine-scale processes, such as light limitation and habitat complexity, and broad-scale processes, such as regional currents and exposure regimes, are important in structuring these diverse deep-reef communities. While some dominant habitat forming biota, including canopy algae, were widely distributed, others, including gorgonians and sea whips, exhibited patchy and restricted distributions across the reef system. In addition to providing the first quantitative and full coverage maps of reef diversity for this area, our modelling revealed that offshore reefs represented a regional diversity hotspot that is of high ecological and conservation value. Regional reef systems should not, therefore, be considered homogenous units in conservation planning and management. Full-coverage maps of the predicted distribution of biota (and associated uncertainty) are likely to be increasingly valuable, not only for conservation planning, but in the ongoing management and monitoring of these less-accessible ecosystems.

  11. Review of samples of water, sediment, tailings, and biota at the Little Bonanza mercury mine, San Luis Obispo County, California

    Science.gov (United States)

    Rytuba, James J.; Hothem, Roger L.; Goldstein, Daniel N.; Brussee, Brianne E.; May, Jason T.

    2011-01-01

    Background and Objectives The Little Bonanza mercury (Hg) mine, located in San Luis Obispo County, California, is a relatively small mine with, a historical total Hg production of about 1,000 flasks. The mine workings and tailings are located in the headwaters of the previously unnamed west fork of Las Tablas Creek (WF Las Tablas Creek), which flows into the Nacimiento Reservoir. Wasterock and tailings eroded from the Little Bonanza Hg Mine have contributed Hg-enriched mine wastes to the headwaters of WF Las Tablas Creek. The mine is located on Federal land managed by the U.S. Bureau of Land Management (BLM), which requested that the U.S. Geological Survey (USGS) measure and characterize Hg and other geochemical constituents in tailings, sediment, water, and biota at and downstream from the minesite. This report is in response that request, from the lead agency which is mandated to conduct a Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) - Removal Site Investigation (RSI). The RSI applies to removal of Hg-contaminated mine waste from the Little Bonanza minesite as a means of reducing Hg transport to WF Las Tablas Creek. This report summarizes data obtained from field sampling of mine tailings, wasterock, sediment, water, and biota at the Little Bonanza Mine that was completed on April 6, 2010. Conditions during sampling were dry and no rain had occurred in the watershed for several weeks. Our results permit a preliminary assessment of the mining sources of Hg and associated chemical constituents that could produce elevated levels of monomethyl mercury (MMeHg) in WF Las Tablas Creek and in biota.

  12. Chemical fingerprinting of petroleum biomarkers in biota samples using retention-time locking chromatography and multivariate analysis.

    Science.gov (United States)

    Bartolomé, Luis; Deusto, Miren; Etxebarria, Nestor; Navarro, Patricia; Usobiaga, Aresatz; Zuloaga, Olatz

    2007-07-20

    This work was conducted to study a new separation and evaluation approach for the chemical fingerprinting of petroleum biomarkers in biota samples. The final aim of this work was to study the correlation between the observed effects in the shore habitats (mussels and limpets) and one pollution source: the oil spill of the Prestige tanker. The method combined a clean-up step of the biota extracts (mussels and limpets), the retention-time locking of the gas chromatographic set up, and the multivariate data analysis of the chromatograms. For clean-up, solid-phase extraction and gel permeation chromatography were compared, and 5g Florisil cartridges assured the lack of interfering compounds in the last extracts. In order to assure reproducible retention times and to avoid the realignment of the chromatograms, the retention-time locking feature of our gas chromatography-mass spectrometry (GC-MS) set up was used. Finally, in the case of multivariate analysis, the GC-MS chromatograms were treated, essentially by derivatization and by normalization, and all the chromatograms at m/z 191 (terpenes), m/z 217-218 (steranes and diasteranes) and m/z 231 (triaromatic steranes) were treated by means of principal component analysis. Furthermore, slightly different four oil samples from the Prestige oil spill were analyzed following the Nordtest method, and the GC-MS chromatograms were considered as the reference chemical fingerprints of the sources. In this sense, the correlation between the studied samples, including sediments and biota samples, and the source candidate was completed by means of a supervised pattern recognition method. As a result, the method proposed in this work was useful to identify the Prestige oil spill as the source of many of the analyzed samples.

  13. Paleoecology of an early Holocene faunal and floral assemblage from the Dows Local Biota of north-central Iowa

    Science.gov (United States)

    Hudak, Curtis M.

    1984-05-01

    The faunas and floras from the Dows Local Biota provide an opportunity to compare Holocene taxa without a cultural bias. The Dows Local Biota is located in a large depression on the back side (north) of the Altamont I Moraine complex within the Des Moines Lobe. The Dows Silt Fauna/Flora ( = DSF; ca. 9380 ± 130 yr B.P.), one horizon of the Dows Local Biota, was collected for plant macrofossils, mollusks, and micromammals. DSF terrestrial gastropods are upland mesic forest dwellers although one species, Strobilops affinis, is characteristic of more xeric forests and may represent open woods. The aquatic gastropods reflect both permanent and periodic waters. DSF micromammals prefer an open, mesic, deciduous forest. The micromammal sympatry is restricted to a small area within the tension zone and deciduous forest belt of west-central Wisconsin. DSF plants are characteristic of upland forests, moist meadowlands or disturbed areas, and aquatic habitats. The DSF plant sympatry is large but restricted to the conifer-hardwood and deciduous forests along the Great Lakes-New England regions. Quantitative climatic data for the combined DSF sympatries suggest that Dows (ca. 9380 yr B.P.) was cooler than at present, and is nearly identical to that achieved by pollen analyses at the Cherokee Sewer-Lake West Okoboji sites (ca. 9000 yr B.P.) in northwest Iowa. Based on common habitat interpretations and sympatries, about 9380 yr B.P. north-central Iowa was cooler and moister than at present and was occupied by an open deciduous forest.

  14. Occurrence of persistent organic pollutants in sediments and biota from Portugal versus European incidence: A critical overview.

    Science.gov (United States)

    Ribeiro, Cláudia; Ribeiro, Ana Rita; Tiritan, Maria Elizabeth

    2016-01-01

    Persistent organic pollutants (POPs) are widespread compounds, such as organohalogenated compounds, polycyclic aromatic hydrocarbons (PAHs) and pesticides, which can be found in all types of environmental compartments. Their presence in the aquatic environment is a worldwide problem, with emphasis on sediments which act as depository and consequently as a source of hydrophobic, recalcitrant and harmful compounds. Besides, these pollutants might affect the reproduction and mortality of living organisms, diverging in their potential to bioaccumulate in tissues. The present paper aims to review the occurrence of POPs in sediments and biota from the coastal, estuarine and river areas of Portugal. The list of the studied compounds comprises organohalogenated compounds, PAHs, organometallic compounds, pesticides, sterols, fatty acids and pharmaceutical compounds. The contamination of sediments by various pollutants is presented, such as PAHs up to 7,350 ng g(-1) found in Sado estuary and polychlorinated biphenyls up to 62.2 ng g(-1) in the case of sediments collected in Ria de Aveiro. The occurrence of these persistent toxic substances in sediments demonstrates aquatic contamination from agricultural, industrial and urban discharges and the concern about the potential risks to aquatic organisms, wildlife and humans. In fact, several classes of POPs have also been found in biota, such as polychlorinated biphenyls up to 810.9 ng g(-1) in sentinel fish from the Douro River estuary and pesticides in bivalves from the Sado River estuary. The importance of further systematic research on sediments and biota is here highlighted to compare the contamination of these two reservoirs; to assess their spatial and temporal variation; and to determine other classes of POPs that were not investigated yet (e.g., industrial compounds, estrogens and many classes of pharmaceuticals).

  15. Partitioning behavior of perfluorinated compounds between sediment and biota in the Pearl River Delta of South China

    International Nuclear Information System (INIS)

    Highlights: • PFCs concentrations in different environmental media, including sediment and biota. • PFCs accumulation between biota and sediment. • Human exposure to PFCs pollution via seafood consumption. - Abstract: Surface sediment and biota were collected from 12 sampling sites – seven along the Pearl River Delta and five along the Hong Kong coastline. Perfluorinated compound (PFC) concentrations were detected using a high-performance-liquid-chromatogram–tandem-mass-spectrometry system. Analytical results indicated that the total PFC concentrations were in the range of 0.15–3.11 ng/g dry weight in sediments, while the total PFC concentrations in oyster and mussel samples were between 0.46–1.96 and 0.66–3.43 ng/g wet weight, respectively. The major types of PFCs detected in the sediment samples were perfluorooctanesulfonic acid (PFOS) and perfluorobutanoic acid (PFBA), with concentrations ranging from low limits of quantification to 0.86 ± 0.12 ng/g dry weight and 1.50 ± 0.26 ng/g dry weight, respectively. In bivalve samples, PFOS was the dominant contaminant with concentrations ranging from 0.25 ± 0.09 to 0.83 ± 0.12 ng/g wet weight in oysters and 0.41 ± 0.14 to 1.47 ± 0.25 ng/g wet weight in mussels. An increase in PFC concentration was found to be correlated with increased human population density in the study areas

  16. A freshwater biodiversity hotspot under pressure – assessing threats and identifying conservation needs for ancient Lake Ohrid

    Directory of Open Access Journals (Sweden)

    G. Kostoski

    2010-07-01

    Full Text Available Freshwater habitats and species living in freshwater are generally more prone to extinction than terrestrial or marine ones. Immediate conservation measures for world-wide freshwater resources are thus of eminent importance. This is particularly true for so called ancient lakes. While these lakes are famous for being evolutionary theatres, often displaying an extraordinarily high degree of biodiversity and endemism, in many cases these biota are also experiencing extreme anthropogenic impact.

    Lake Ohrid, the European biodiversity hotspot, is a prime example for a lake with a magnitude of narrow range endemic taxa that are under increasing anthropogenic pressure. Unfortunately, evidence for a "creeping biodiversity crisis" has accumulated over the last decades, and major socio-political changes have gone along with human-mediated environmental changes.

    Based on field surveys, monitoring data, published records, and expert interviews, we aimed to (1 assess threats to Lake Ohrids' (endemic biodiversity, (2 summarize existing conservation activities and strategies, and (3 outline future conservation needs for Lake Ohrid. We compiled threats to both specific taxa (and in cases to particular species as well as to the lake ecosystems itself. Major conservation concerns identified for Lake Ohrid are: (1 watershed impacts, (2 agriculture and forestry, (3 tourism and population growth, (4 non-indigenous species, (5 habitat alteration or loss, (6 unsustainable exploitation of fisheries, and (7 global climate change.

    Of the 11 IUCN (International Union for Conservation of Nature and Natural Resources threat classes scored, seven have moderate and three severe impacts. These latter threat classes are energy production and mining, biological resource use, and pollution. We review and discuss institutional responsibilities, environmental monitoring and ecosystem management, existing parks and reserves, biodiversity and species

  17. The history of Lake Maggiore industrial pollution traced through lake sediment and long term monitoring of the biota

    OpenAIRE

    Aldo MARCHETTO; Guzzella, Licia; Binelli, Andrea; Roberta BETTINETTI; Andrea LAMI; Manca, Marina; Laura MARZIALI; Piscia, Roberta; Volta, Pietro

    2015-01-01

    In Lake Maggiore large watershed (ca. 6,600 sq. km), industrial activities along the XX century led to the discharge into the lake or its tributaries of several pollutants, such as DDT, PCBs and mercury. Other pollutants, such as PAHs and flame retardants (such as PBDEs) are still reaching the lake. Analyses of some of these pollutants in lake biota were performed continuously since 1998 and form a unique time series. We used in parallel lake sediment cores to infer the history of lake contam...

  18. The impact of the Fukushima nuclear accident on marine biota: Retrospective assessment of the first year and perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Vives i Batlle, Jordi, E-mail: jordi.vives.i.batlle@sckcen.be [Biosphere Impact Studies Unit, Belgian Nuclear Research Centre SCK-CEN, Boeretang 200, 2400 Mol (Belgium); Aono, Tatsuo [National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Brown, Justin E.; Hosseini, Ali [Norwegian Radiation Protection Authority, Grini næringspark 13, 1332 Østerås (Norway); CERAD Centre of Excellence, Grini næringspark 13, 1332 Østerås (Norway); Garnier-Laplace, Jacqueline [Institute for Radioprotection and Nuclear Safety, Department for research and expertise in environmental risks, PRP-ENV/SERIS, Cadarache, Building 159, 13115 Saint-Paul-Lez-Durance Cedex (France); Sazykina, Tatiana [State Institution Research and Production Association Typhoon, 4 Pobedy Str., Obninsk, Kaluga Region 249038 (Russian Federation); Steenhuisen, Frits [Arctic Centre, University of Groningen, Groningen (Netherlands); Strand, Per [Norwegian Radiation Protection Authority, Grini næringspark 13, 1332 Østerås (Norway); CERAD Centre of Excellence, Grini næringspark 13, 1332 Østerås (Norway)

    2014-07-01

    An international study under the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) was performed to assess radiological impact of the nuclear accident at the Fukushima-Daiichi Nuclear Power Station (FDNPS) on the marine environment. This work constitutes the first international assessment of this type, drawing upon methodologies that incorporate the most up-to-date radioecological models and knowledge. To quantify the radiological impact on marine wildlife, a suite of state-of-the-art approaches to assess exposures to Fukushima derived radionuclides of marine biota, including predictive dynamic transfer modelling, was applied to a comprehensive dataset consisting of over 500 sediment, 6000 seawater and 5000 biota data points representative of the geographically relevant area during the first year after the accident. The dataset covers the period from May 2011 to August 2012. The method used to evaluate the ecological impact consists of comparing dose (rates) to which living species of interest are exposed during a defined period to critical effects values arising from the literature. The assessed doses follow a highly variable pattern and generally do not seem to indicate the potential for effects. A possible exception of a transient nature is the relatively contaminated area in the vicinity of the discharge point, where effects on sensitive endpoints in individual plants and animals might have occurred in the weeks directly following the accident. However, impacts on population integrity would have been unlikely due to the short duration and the limited space area of the initially high exposures. Our understanding of the biological impact of radiation on chronically exposed plants and animals continues to evolve, and still needs to be improved through future studies in the FDNPS marine environment. - Highlights: • UNSCEAR assessment of the Fukushima accident impact on the marine environment. • The study covers the period from

  19. A dynamic model to estimate the dose rate of marine biota (K-BIOTADYN- M) and its application to the Fukushima accident

    Energy Technology Data Exchange (ETDEWEB)

    Keum, Dong-Kwon; Jun, In; Kim, Byeong-Ho; Lim, Kwang-Muk; Choi, Yong-ho [Nuclear Environmental Safety Research Division, Korea Atomic Energy Research Institute, 989-111 Daedeodaero, Yuseong, Daejeon, 305-353 (Korea, Republic of)

    2014-07-01

    This paper describes a dynamic compartment model, K-BIOTA-DYN-M, to assess the activity concentration and dose rate of marine biota when the seawater activity varies with time, which is likely for the early phase after an accident. The model consists of seven compartments, phytoplankton, zooplankton, prey fish, benthic fish, crustacean, mollusk, and macro-algae. The phytoplankton compartment is assumed to be instantaneously in equilibrium with the seawater owing to the huge mass of the plankton in sea, and thus the activity of the phytoplankton is estimated using the equilibrium concentration ratio. The other compartments intake the radioactivity from both water and food, and lose the radioactivity by the biological elimination and radioactivity decay. Given the seawater activity, a set of ordinary differential equations representing the activity balance for biota is solved to obtain the time-variant activity concentration of biota, which is subsequently used to calculate the internal dose rate. The key parameters include the water intake rate, the daily feeding rate, the assimilation efficiency of radionuclides from food, the occupancy factor, and so on. The model has been applied to predict the activity concentration and dose rate of marine biota as a result the Fukushima nuclear accident on March 11, 2011. Using the seawater activities measured at three locations near the Fukushima NPPs, the time-variant activity concentration and dose rate during a few months after an accident for the seven model biota have been estimated. The preliminary results showed that the activity concentration of {sup 137}Cs in fish inhabiting the sea close to the Fukushima Daiichi NPP increased up to tenth-thousands of Bq/kg around the peak time of the seawater activity. This level is much higher than the food consumption restriction level for human protection; however, the estimated total dose rates (internal + external) for biota during the entire simulation time were all much less

  20. Mechanical challenges to freshwater residency in sharks and rays.

    Science.gov (United States)

    Gleiss, Adrian C; Potvin, Jean; Keleher, James J; Whitty, Jeff M; Morgan, David L; Goldbogen, Jeremy A

    2015-04-01

    Major transitions between marine and freshwater habitats are relatively infrequent, primarily as a result of major physiological and ecological challenges. Few species of cartilaginous fish have evolved to occupy freshwater habitats. Current thought suggests that the metabolic physiology of sharks has remained a barrier to the diversification of this taxon in freshwater ecosystems. Here, we demonstrate that the physical properties of water provide an additional constraint for this species-rich group to occupy freshwater systems. Using hydromechanical modeling, we show that occurrence in fresh water results in a two- to three-fold increase in negative buoyancy for sharks and rays. This carries the energetic cost of lift production and results in increased buoyancy-dependent mechanical power requirements for swimming and increased optimal swim speeds. The primary source of buoyancy, the lipid-rich liver, offers only limited compensation for increased negative buoyancy as a result of decreasing water density; maintaining the same submerged weight would involve increasing the liver volume by very large amounts: 3- to 4-fold in scenarios where liver density is also reduced to currently observed minimal levels and 8-fold without any changes in liver density. The first data on body density from two species of elasmobranch occurring in freshwater (the bull shark Carcharhinus leucas, Müller and Henle 1839, and the largetooth sawfish Pristis pristis, Linnaeus 1758) support this hypothesis, showing similar liver sizes as marine forms but lower liver densities, but the greatest negative buoyancies of any elasmobranch studied to date. Our data suggest that the mechanical challenges associated with buoyancy control may have hampered the invasion of freshwater habitats in elasmobranchs, highlighting an additional key factor that may govern the predisposition of marine organisms to successfully establish in freshwater habitats. PMID:25573824

  1. Anthropogenic litter in urban freshwater ecosystems: distribution and microbial interactions.

    Directory of Open Access Journals (Sweden)

    Timothy Hoellein

    Full Text Available Accumulation of anthropogenic litter (i.e. garbage; AL and its ecosystem effects in marine environments are well documented. Rivers receive AL from terrestrial habitats and represent a major source of AL to marine environments, but AL is rarely studied within freshwater ecosystems. Our objectives were to 1 quantify AL density in urban freshwaters, 2 compare AL abundance among freshwater, terrestrial, and marine ecosystems, and 3 characterize the activity and composition of AL biofilms in freshwater habitats. We quantified AL from the Chicago River and Chicago's Lake Michigan shoreline, and found that AL abundance in Chicago freshwater ecosystems was comparable to previously reported data for marine and terrestrial ecosystems, although AL density and composition differed among habitats. To assess microbial interactions with AL, we incubated AL and natural substrates in 3 freshwater ecosystems, quantified biofilm metabolism as gross primary production (GPP and community respiration (CR, and characterized biofilm bacterial community composition via high-throughput sequencing of 16S rRNA genes. The main driver of biofilm community composition was incubation location (e.g., river vs pond, but there were some significant differences in biofilm composition and metabolism among substrates. For example, biofilms on organic substrates (cardboard and leaves had lower GPP than hard substrates (glass, plastic, aluminum and tiles. In addition, bacterial communities on organic substrates were distinct in composition from those on hard substrates, with higher relative abundances of bacteria associated with cellulose decomposition. Finally, we used our results to develop a conceptual diagram designed to unite the study of AL in terrestrial and freshwater environments with the well-established field of marine debris research. We suggest this broad perspective will be useful for future studies which synthesize AL sources, ecosystem effects, and fate across

  2. Anthropogenic litter in urban freshwater ecosystems: distribution and microbial interactions.

    Science.gov (United States)

    Hoellein, Timothy; Rojas, Miguel; Pink, Adam; Gasior, Joseph; Kelly, John

    2014-01-01

    Accumulation of anthropogenic litter (i.e. garbage; AL) and its ecosystem effects in marine environments are well documented. Rivers receive AL from terrestrial habitats and represent a major source of AL to marine environments, but AL is rarely studied within freshwater ecosystems. Our objectives were to 1) quantify AL density in urban freshwaters, 2) compare AL abundance among freshwater, terrestrial, and marine ecosystems, and 3) characterize the activity and composition of AL biofilms in freshwater habitats. We quantified AL from the Chicago River and Chicago's Lake Michigan shoreline, and found that AL abundance in Chicago freshwater ecosystems was comparable to previously reported data for marine and terrestrial ecosystems, although AL density and composition differed among habitats. To assess microbial interactions with AL, we incubated AL and natural substrates in 3 freshwater ecosystems, quantified biofilm metabolism as gross primary production (GPP) and community respiration (CR), and characterized biofilm bacterial community composition via high-throughput sequencing of 16S rRNA genes. The main driver of biofilm community composition was incubation location (e.g., river vs pond), but there were some significant differences in biofilm composition and metabolism among substrates. For example, biofilms on organic substrates (cardboard and leaves) had lower GPP than hard substrates (glass, plastic, aluminum and tiles). In addition, bacterial communities on organic substrates were distinct in composition from those on hard substrates, with higher relative abundances of bacteria associated with cellulose decomposition. Finally, we used our results to develop a conceptual diagram designed to unite the study of AL in terrestrial and freshwater environments with the well-established field of marine debris research. We suggest this broad perspective will be useful for future studies which synthesize AL sources, ecosystem effects, and fate across multiple ecosystem

  3. Large-scale degradation of Amazonian freshwater ecosystems.

    Science.gov (United States)

    Castello, Leandro; Macedo, Marcia N

    2016-03-01

    Hydrological connectivity regulates the structure and function of Amazonian freshwater ecosystems and the provisioning of services that sustain local populations. This connectivity is increasingly being disrupted by the construction of dams, mining, land-cover changes, and global climate change. This review analyzes these drivers of degradation, evaluates their impacts on hydrological connectivity, and identifies policy deficiencies that hinder freshwater ecosystem protection. There are 154 large hydroelectric dams in operation today, and 21 dams under construction. The current trajectory of dam construction will leave only three free-flowing tributaries in the next few decades if all 277 planned dams are completed. Land-cover changes driven by mining, dam and road construction, agriculture and cattle ranching have already affected ~20% of the Basin and up to ~50% of riparian forests in some regions. Global climate change will likely exacerbate these impacts by creating warmer and dryer conditions, with less predictable rainfall and more extreme events (e.g., droughts and floods). The resulting hydrological alterations are rapidly degrading freshwater ecosystems, both independently and via complex feedbacks and synergistic interactions. The ecosystem impacts include biodiversity loss, warmer stream temperatures, stronger and more frequent floodplain fires, and changes to biogeochemical cycles, transport of organic and inorganic materials, and freshwater community structure and function. The impacts also include reductions in water quality, fish yields, and availability of water for navigation, power generation, and human use. This degradation of Amazonian freshwater ecosystems cannot be curbed presently because existing policies are inconsistent across the Basin, ignore cumulative effects, and overlook the hydrological connectivity of freshwater ecosystems. Maintaining the integrity of these freshwater ecosystems requires a basinwide research and policy framework

  4. Large-scale degradation of Amazonian freshwater ecosystems.

    Science.gov (United States)

    Castello, Leandro; Macedo, Marcia N

    2016-03-01

    Hydrological connectivity regulates the structure and function of Amazonian freshwater ecosystems and the provisioning of services that sustain local populations. This connectivity is increasingly being disrupted by the construction of dams, mining, land-cover changes, and global climate change. This review analyzes these drivers of degradation, evaluates their impacts on hydrological connectivity, and identifies policy deficiencies that hinder freshwater ecosystem protection. There are 154 large hydroelectric dams in operation today, and 21 dams under construction. The current trajectory of dam construction will leave only three free-flowing tributaries in the next few decades if all 277 planned dams are completed. Land-cover changes driven by mining, dam and road construction, agriculture and cattle ranching have already affected ~20% of the Basin and up to ~50% of riparian forests in some regions. Global climate change will likely exacerbate these impacts by creating warmer and dryer conditions, with less predictable rainfall and more extreme events (e.g., droughts and floods). The resulting hydrological alterations are rapidly degrading freshwater ecosystems, both independently and via complex feedbacks and synergistic interactions. The ecosystem impacts include biodiversity loss, warmer stream temperatures, stronger and more frequent floodplain fires, and changes to biogeochemical cycles, transport of organic and inorganic materials, and freshwater community structure and function. The impacts also include reductions in water quality, fish yields, and availability of water for navigation, power generation, and human use. This degradation of Amazonian freshwater ecosystems cannot be curbed presently because existing policies are inconsistent across the Basin, ignore cumulative effects, and overlook the hydrological connectivity of freshwater ecosystems. Maintaining the integrity of these freshwater ecosystems requires a basinwide research and policy framework

  5. Behavior of technetium in freshwater environments

    International Nuclear Information System (INIS)

    In a previous study, /sup 95m/Tc, as a pertechnetate, was released to a small, experimental, freshwater pond, and the concentrations were determined in biotic and abiotic components of the pond ecosystem. A simple mathematical model was developed to predict the concentration of /sup 95m/Tc in fish and snails. Results from this study indicated that uptake through the food chain was an important source of technetium to the higher trophic levels (i.e., fish). In the current study, an experimental pond was spiked with /sup 95m/Tc in the pertechnetate form, and the concentrations of /sup 95m/Tc were measured in the lower trophic levels. Emphasis was placed on measuring the concentration of /sup 95m/Tc in zooplankton, benthic invertebrates, and the aquatic macrophyte Elodea canadensis. Fish were excluded from the pond to allow the development of a large zooplankton population. The concentration of /sup 95m/Tc in water decreased from 0.75 Bq/mL 1 h after the pond was spiked, to 0.21 Bq/mL at 20 d. Throughout the experiment, at least 98% of the /sup 95m/Tc in the water was in the dissolved fraction (0.4 μm). Zooplankton accumulated /sup 95m/Tc rapidly, having concentration factors (Bq/g sample wet wt. divided by Bq/g water) ranging from 3 at 4 h to 36 at 20 d. Concentration factors ranged from 3 to 8 for benthic insects and from 1 to 62 for the aquatic macrophyte

  6. Assessment of impact to non-human biota from a generic waste repository in the UK

    International Nuclear Information System (INIS)

    The UK Nuclear Decommissioning Authority Radioactive Waste Management Directorate (NDA RWMD, formerly Nirex UK Ltd), has played a leading role in establishing knowledge on geological disposal of radioactive waste in the UK. In 2001, a study was commissioned of the potential impact of releases of radio-nuclides from a generic repository on plants and animals). More recently, the NDA commissioned Enviros Consulting to report on developments in policy and in approaches for assessing impacts of radioactivity on non-human biota, that have occurred since the previous study. A trial application of the ERICA assessment tool, to reassess the impact of releases from a generic deep repository using similar source data as used previously (Nirex, 2003), formed part of this work. This paper summarizes the results of the reassessment exercise; key differences between the two assessments are identified and explored. The applicability and capabilities of the ERICA tool to assessments of releases from a waste repository are discussed and priorities for future work are identified. Conclusions: The peak activity concentrations predicted to arise from releases from a generic repository would not lead to a significant increase in environmental risk. Indeed, a substantial proportion of the calculated dose rates are due to natural series radio-nuclides at concentrations that are well below typical background levels. In the previous study, the highest (weighted) absorbed dose rate in an aquatic system was predicted to be around 6.5 micoGy h-1, which is of the same order of magnitude as those predicted in the current study; the significance of the contribution of natural series radionuclides is also common to both studies. However, previously, the authors concluded that it was not possible to undertake a detailed assessment for the terrestrial system, due to the paucity of data on concentration ratios. While the derivation of default concentration factors, as part of the ERICA project, has

  7. Geosites of Lithuania as an environment for dwelling of specific biota: geo- and biodiversity interactions

    Science.gov (United States)

    Skridlaite, Grazina; Motiejunaite, Jurga; Jukoniene, Ilona; Prigodina Lukosiene, Ingrida

    2016-04-01

    also in the neighbouring countries. In general, protection of geo-diversity coincides well with protection of narrowly specialized cryptogams, e.g. overgrowing of boulder fields with tall herbs and shrubs also has adversary effect on rock-dwelling lichens. Shading of Devonian outcrops and quarries by trees and shrubs may obscure rocky surfaces and destroy lichens, but favour an establishment of sciophyllous bryophytes. No doubt that cleaning of surfaces of single boulders that are well-known nature monuments prevents an establishment and growth of lichens and bryophytes. However, most of the geological monuments which are subjected to cleaning are situated in localities under strong anthropogenic impact and therefore not suitable for settlement of the rare and protected species. Though conservation conflicts arise even when protecting different species of biota, not to mention conservation of bio- versus geo-diversity, most of the conservation measures for the geoheritage in Lithuania are also suitable for rock-inhabiting lichens and bryophytes. Protection status and measures should be negotiated by bio-and geoscientists, and legislation for bio- and geo-diversity protection should be improved. Khodosovtsev, A., Vondrák, J., Naumovich, A., Kocourková, J., Vondráková, O., Motiejūnaitė, J., 2012. Nova Hedwigia, 95(1-2): 211-220.

  8. Worldwide Laboratory Comparison on the Determination of Trace Elements in IAEA-452 Biota Sample

    International Nuclear Information System (INIS)

    educational opportunities, enhanced mutual trust in results and methodology and objective evidence for accreditation purposes The present ILC was designed in order to evaluate the measurement performance of participating laboratories for the analysis of trace elements in biota samples. The test material was distributed to 150 laboratories worldwide and the results from 143 laboratories in 59 countries were received by the end 2009. The data reported by the laboratories, together with the technical and statistical evaluations of the results for each element, are included in this report. The performance of the participant laboratories was assessed through evaluating Z-scores in accordance with ISO 13528 and the International Harmonised Protocol for the Proficiency Testing of Analytical Chemistry Laboratories. On the basis of the outcome from previous ILCs, organised by NAEL for the same population of laboratories, the standard deviation for proficiency assessment (also called target standard deviation) was fixed to 12.5%. Z-scores obtained from this ILC results should assist chemists to make appropriate modifications in their laboratory analytical procedures in order to improve data quality. All results were treated confidentially and each laboratory was identified with a code number for anonymity.

  9. Linking mercury, carbon, and nitrogen stable isotopes in Tibetan biota: Implications for using mercury stable isotopes as source tracers.

    Science.gov (United States)

    Xu, Xiaoyu; Zhang, Qianggong; Wang, Wen-Xiong

    2016-05-06

    Tibetan Plateau is located at a mountain region isolated from direct anthropogenic sources. Mercury concentrations and stable isotopes of carbon, nitrogen, and mercury were analyzed in sediment and biota for Nam Co and Yamdrok Lake. Biotic mercury concentrations and high food web magnification factors suggested that Tibetan Plateau is no longer a pristine site. The primary source of methylmercury was microbial production in local sediment despite the lack of direct methylmercury input. Strong ultraviolet intensity led to extensive photochemical reactions and up to 65% of methylmercury in water was photo-demethylated before entering the food webs. Biota displayed very high Δ(199)Hg signatures, with some highest value (8.6%) ever in living organisms. The δ(202)Hg and Δ(199)Hg in sediment and biotic samples increased with trophic positions (δ(15)N) and %methylmercury. Fish total length closely correlated to δ(13)C and Δ(199)Hg values due to dissimilar carbon sources and methylmercury pools in different living waters. This is the first mercury isotope study on high altitude lake ecosystems that demonstrated specific isotope fractionations of mercury under extreme environmental conditions.

  10. Fate of a broad spectrum of perfluorinated compounds in soils and biota from Tierra del Fuego and Antarctica

    International Nuclear Information System (INIS)

    In this study, the presence of 18 perfluorinated compounds was investigated in biota and environmental samples from the Antarctica and Tierra de Fuego, which were collected during a sampling campaign carried out along February and March 2010. 61 samples were analysed including fish, superficial soils, guano, algae, dung and tissues of Papua penguin by liquid chromatography coupled to tandem mass spectrometry. The concentrations of PFCs were ranging from 0.10 to 240 ng/g for most of the samples except for penguin dung, which presented levels between 95 and 603 ng/g for perfluorooctane sulfonate, and guano samples from Ushuaia, with concentration levels of 1190–2480 ng/g of perfluorohexanoic acid. PFCs acids presented, in general, the highest levels of concentration and perfluorooctanesulfonate was the most frequently found compound. The present study provides a significant amount of results, which globally supports the previous studies, related to the transport, deposition, biodegradation and bioaccumulation patterns of PFCs. - Highlights: ► 61 samples from the Antarctica and Tierra de Fuego analysed for the presence of 18 perfluorinated compounds. ► Acid compounds presented the highest levels of concentration and perfluorooctane sulfonate was the most frequently found. ► Concentrations in algae much higher than those in soils. ► Data supporting existing models for the transport, deposition, biodegradation and bioaccumulation patterns are presented. - 18 perfluorinated compounds assessed in biota and environmental samples from Tierra del Fuego and the Antarctica. Concentrations related to Compounds properties.

  11. Assessment of risk to aquatic biota from elevated salinity -- a case study from the Hunter River, Australia.

    Science.gov (United States)

    Muschal, Monika

    2006-05-01

    An ecological risk assessment was performed on salinity levels of the Hunter River and its tributaries to respond to concerns that high salinity may be damaging aquatic ecosystems. Probabilistic techniques were used to assess likelihood and consequence, and hence the risk to aquatic biota from salinity. Continuous electrical conductivity distributions were used to describe the likelihood that high salinity would occur (exposure dataset) and toxicity values were compiled from the limited literature sources available to describe the consequence of high salinity (effects dataset). The assessment was preliminary in the sense that it modelled risk on the basis of existing data and did not undertake site-specific toxicity testing. Some sections of the Hunter River catchment have geologies that are saline because of their marine origins. Catchment development has increased the liberation rates of salts into surface-waters. Such modifying activities include coal-mining, power generation and land clearing. The aquatic biota of tributaries had a greater risk of impairment from high salinity than that of the Hunter River. High salinities in the tributaries were attributed to the combined factors of naturally saline geologies, increased liberation of salts due to modification of the landscape, and reduced dilution by flushing flows. A salinity guideline trigger value of 1100 mg L(-1) was recommended.

  12. Biomonitoring study of heavy metals in biota and sediments in the South Eastern coast of Mediterranean sea, Egypt.

    Science.gov (United States)

    Abdallah, Maha A M; Abdallah, Aly M A

    2008-11-01

    Concentrations of Cd, Cu, Co, Zn, Mn and Fe were determined in biota and sediment samples collected from the Eastern Harbour and El-Mex Bay in the Mediterranean Sea, Egypt. The levels of Cu, Co, Zn, Mn and Fe in the macroalgae, Ulva lactuca, Enteromorpha compressa (green algae) and Jania rubens (red algae), recorded high concentrations except for Cd. Moreover, Fe was the most predominant metal in the seaweed. The two species of bivalves, Donax trunculus and Paphia textile, showed different amounts of metals in their tissue. The abundance of heavy metal concentrations in the mussel samples was found in the order Fe> Zn> Mn> Cu> Co> Cd and Fe> Zn> Mn> Cu> Cd> Co, respectively for the two species. The metals concentrations were generally higher compared with the previous studies in mussels from the same area. The levels of metals accumulated in the investigated fish samples, Saurida undosquamis, Siganus rivulatus, Lithognathus mormyrus and Sphyraena sphyraena, were higher than those of Marmara Sea (Turkey), for Co and Cd and lower for Cu, Zn, Mn and Fe. El-Mex Bay having the highest metals concentration in sediments as their order of abundance were Fe> Zn> Mn> Cu> Cd> Co. Nevertheless, a high variability in the metal levels occurs among the studied algae and biota and also between the investigated Harbour. A significant correlations (p < 0.05) were found for each of Zn and Fe in P. textile and of Co in D. trunculus relative to their concentrations in surficial sediments. PMID:18074236

  13. Linking mercury, carbon, and nitrogen stable isotopes in Tibetan biota: Implications for using mercury stable isotopes as source tracers

    Science.gov (United States)

    Xu, Xiaoyu; Zhang, Qianggong; Wang, Wen-Xiong

    2016-05-01

    Tibetan Plateau is located at a mountain region isolated from direct anthropogenic sources. Mercury concentrations and stable isotopes of carbon, nitrogen, and mercury were analyzed in sediment and biota for Nam Co and Yamdrok Lake. Biotic mercury concentrations and high food web magnification factors suggested that Tibetan Plateau is no longer a pristine site. The primary source of methylmercury was microbial production in local sediment despite the lack of direct methylmercury input. Strong ultraviolet intensity led to extensive photochemical reactions and up to 65% of methylmercury in water was photo-demethylated before entering the food webs. Biota displayed very high Δ199Hg signatures, with some highest value (8.6%) ever in living organisms. The δ202Hg and Δ199Hg in sediment and biotic samples increased with trophic positions (δ15N) and %methylmercury. Fish total length closely correlated to δ13C and Δ199Hg values due to dissimilar carbon sources and methylmercury pools in different living waters. This is the first mercury isotope study on high altitude lake ecosystems that demonstrated specific isotope fractionations of mercury under extreme environmental conditions.

  14. Pyrite framboids associated with the Mesozoic Jehol Biota in northeastern China: Implications for microenvironment during early fossilization

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Despite of the recent influx of reports describing important fossil specimens from the Mesozoic Jehol Biota, detailed information on the mechanism of fossilization and paleoenvironment in which these fossils were deposited is scanty. We present an analysis of microenvironment based upon scanning electron microscope observations of in situ pyrite framboids and microcrystallines of plant and vertebrate feather fossils in the Jehol Biota. Pyrite microcrystallines and framboids occur extensively inside and on surface of plant fossils.Framboids found on feathers and in sedimentary matrix were in a lower abundance. These framboids have diameters ranging from 6 μm to 31 μm with an average of 20 μm, indicating a dysoxic aqueous condition with free oxygen level less than 30 μmol/L for the microenvironment where these framboids were formed. The outgrowth of framboids inside plant tissues suggests the presence of water molecules and free oxygen at the cellular level during pyritization; the relative timing between tissue decay and framboid formation implies a rapid tissue degradation occurred during the very early stage of fossilization. This line of reasoning is consistent with the observation that cell level structure of plant fossils from these deposits is rarely preserved. We propose a "fossil envelop" model to accommodate the different geochemical conditions between the microenvironment surrounding the fossil material and the macroenvironment of background lake bottom water.

  15. Arctic Ocean freshwater as a trigger for abrupt climate change

    Science.gov (United States)

    Bradley, Raymond; Condron, Alan; Coletti, Anthony

    2016-04-01

    The cause of the Younger Dryas cooling remains unresolved despite decades of debate. Current arguments focus on either freshwater from Glacial Lake Agassiz drainage through the St Lawrence or the MacKenzie river systems. High resolution ocean modeling suggests that freshwater delivered to the North Atlantic from the Arctic Ocean through Fram Strait would have had more of an impact on Atlantic Meridional Overturning Circulation (AMOC) than freshwater from the St Lawrence. This has been interpreted as an argument for a MacKenzie River /Lake Agassiz freshwater source. However, it is important to note that although the modeling identifies Fram Strait as the optimum location for delivery of freshwater to disrupt the AMOC, this does not mean the freshwater source came from Lake Agassiz. Another potential source of freshwater is the Arctic Ocean ice cover itself. During the LGM, ice cover was extremely thick - many tens of meters in the Canada Basin (at least), resulting in a hiatus in sediment deposition there. Extreme ice thickness was related to a stagnant circulation, very low temperatures and continuous accumulation of snow on top of a base of sea-ice. This resulted in a large accumulation of freshwater in the Arctic Basin. As sea-level rose and a more modern circulation regime became established in the Arctic, this freshwater was released from the Arctic Ocean through Fram Strait, leading to extensive sea-ice formation in the North Atlantic (Greenland Sea) and a major reduction in the AMOC. Here we present new model results and a review of the paleoceanographic evidence to support this hypothesis. The bottom line is that the Arctic Ocean was likely a major player in causing abrupt climate change in the past, via its influence on the AMOC. Although we focus here on the Younger Dryas, the Arctic Ocean has been repeatedly isolated from the world ocean during glacial periods of the past. When these periods of isolation ended, it is probable that there were significant

  16. Freshwater biodiversity: importance, threats, status and conservation challenges.

    Science.gov (United States)

    Dudgeon, David; Arthington, Angela H; Gessner, Mark O; Kawabata, Zen-Ichiro; Knowler, Duncan J; Lévêque, Christian; Naiman, Robert J; Prieur-Richard, Anne-Hélène; Soto, Doris; Stiassny, Melanie L J; Sullivan, Caroline A

    2006-05-01

    Freshwater biodiversity is the over-riding conservation priority during the International Decade for Action - 'Water for Life' - 2005 to 2015. Fresh water makes up only 0.01% of the World's water and approximately 0.8% of the Earth's surface, yet this tiny fraction of global water supports at least 100000 species out of approximately 1.8 million - almost 6% of all described species. Inland waters and freshwater biodiversity constitute a valuable natural resource, in economic, cultural, aesthetic, scientific and educational terms. Their conservation and management are critical to the interests of all humans, nations and governments. Yet this precious heritage is in crisis. Fresh waters are experiencing declines in biodiversity far greater than those in the most affected terrestrial ecosystems, and if trends in human demands for water remain unaltered and species losses continue at current rates, the opportunity to conserve much of the remaining biodiversity in fresh water will vanish before the 'Water for Life' decade ends in 2015. Why is this so, and what is being done about it? This article explores the special features of freshwater habitats and the biodiversity they support that makes them especially vulnerable to human activities. We document threats to global freshwater biodiversity under five headings: overexploitation; water pollution; flow modification; destruction or degradation of habitat; and invasion by exotic species. Their combined and interacting influences have resulted in population declines and range reduction of freshwater biodiversity worldwide. Conservation of biodiversity is complicated by the landscape position of rivers and wetlands as 'receivers' of land-use effluents, and the problems posed by endemism and thus non-substitutability. In addition, in many parts of the world, fresh water is subject to severe competition among multiple human stakeholders. Protection of freshwater biodiversity is perhaps the ultimate conservation challenge

  17. Freshwater biodiversity: importance, threats, status and conservation challenges.

    Science.gov (United States)

    Dudgeon, David; Arthington, Angela H; Gessner, Mark O; Kawabata, Zen-Ichiro; Knowler, Duncan J; Lévêque, Christian; Naiman, Robert J; Prieur-Richard, Anne-Hélène; Soto, Doris; Stiassny, Melanie L J; Sullivan, Caroline A

    2006-05-01

    Freshwater biodiversity is the over-riding conservation priority during the International Decade for Action - 'Water for Life' - 2005 to 2015. Fresh water makes up only 0.01% of the World's water and approximately 0.8% of the Earth's surface, yet this tiny fraction of global water supports at least 100000 species out of approximately 1.8 million - almost 6% of all described species. Inland waters and freshwater biodiversity constitute a valuable natural resource, in economic, cultural, aesthetic, scientific and educational terms. Their conservation and management are critical to the interests of all humans, nations and governments. Yet this precious heritage is in crisis. Fresh waters are experiencing declines in biodiversity far greater than those in the most affected terrestrial ecosystems, and if trends in human demands for water remain unaltered and species losses continue at current rates, the opportunity to conserve much of the remaining biodiversity in fresh water will vanish before the 'Water for Life' decade ends in 2015. Why is this so, and what is being done about it? This article explores the special features of freshwater habitats and the biodiversity they support that makes them especially vulnerable to human activities. We document threats to global freshwater biodiversity under five headings: overexploitation; water pollution; flow modification; destruction or degradation of habitat; and invasion by exotic species. Their combined and interacting influences have resulted in population declines and range reduction of freshwater biodiversity worldwide. Conservation of biodiversity is complicated by the landscape position of rivers and wetlands as 'receivers' of land-use effluents, and the problems posed by endemism and thus non-substitutability. In addition, in many parts of the world, fresh water is subject to severe competition among multiple human stakeholders. Protection of freshwater biodiversity is perhaps the ultimate conservation challenge

  18. Malacofauna of Holocene freshwater calcareous deposits of Lithuania

    Science.gov (United States)

    Sanko, Aleksander; Vainorius, Julius; Melešytė, Monika

    2010-12-01

    The malacofauna of freshwater calcareous deposits of Lithuania was studied. Sections of the Mūšos Tyrelis and Pabaliai peatbogs near the town of Šiauliai, as well as Dubičiai section (three sites) in SE Lithuania and Dūkštos in Central Lithuania were investigated. Freshwater calcareous deposits are attributed to three groups of facies - lacustrine, valley-hollow-peatbog and terrestrial. Each group of facies consists of sub-facies (freshwater lime, "gazha" (limno-calcite), peat-tufa, calcareous tufa, "mada") varying the formation conditions, composition and other characteristics. The mollusc fauna in the lacustrine facies group (Mūšos Tyrelis and Pabaliai sections) is represented by lacustrine species containing euryecological freshwater molluscs. Terrestrial and rheophilous species are rare or absent in the lacustrine group. Deposits of valley-hollow-peatbog facies contain shells of euryecological freshwater and lacustrine molluscs together with rheophyl shells, sometimes with abundant terrestrial shells, as was observed in the Dubičiai-4 section. A characteristic feature of the terrestrial facies group deposits is the occurrence of solely terrestrial mollusc shells (Dūkštos section).

  19. Taking High Conservation Value from Forests to Freshwaters

    Science.gov (United States)

    Abell, Robin; Morgan, Siân K.; Morgan, Alexis J.

    2015-07-01

    The high conservation value (HCV) concept, originally developed by the Forest Stewardship Council, has been widely incorporated outside the forestry sector into companies' supply chain assessments and responsible purchasing policies, financial institutions' investment policies, and numerous voluntary commodity standards. Many, if not most, of these newer applications relate to production practices that are likely to affect freshwater systems directly or indirectly, yet there is little guidance as to whether or how HCV can be applied to water bodies. We focus this paper on commodity standards and begin by exploring how prominent standards currently address both HCVs and freshwaters. We then highlight freshwater features of high conservation importance and examine how well those features are captured by the existing HCV framework. We propose a new set of freshwater `elements' for each of the six values and suggest an approach for identifying HCV Areas that takes out-of-fence line impacts into account, thereby spatially extending the scope of existing methods to define HCVs. We argue that virtually any non-marine HCV assessment, regardless of the production sector, should be expanded to include freshwater values, and we suggest how to put those recommendations into practice.

  20. Bistability of mangrove forests and competition with freshwater plants

    Science.gov (United States)

    Jiang, Jiang; Fuller, Douglas O; Teh, Su Yean; Zhai, Lu; Koh, Hock Lye; DeAngelis, Donald L.; Sternberg, L.D.S.L.

    2015-01-01

    Halophytic communities such as mangrove forests and buttonwood hammocks tend to border freshwater plant communities as sharp ecotones. Most studies attribute this purely to underlying physical templates, such as groundwater salinity gradients caused by tidal flux and topography. However, a few recent studies hypothesize that self-reinforcing feedback between vegetation and vadose zone salinity are also involved and create a bistable situation in which either halophytic dominated habitat or freshwater plant communities may dominate as alternative stable states. Here, we revisit the bistability hypothesis and demonstrate the mechanisms that result in bistability. We demonstrate with remote sensing imagery the sharp boundaries between freshwater hardwood hammock communities in southern Florida and halophytic communities such as buttonwood hammocks and mangroves. We further document from the literature how transpiration of mangroves and freshwater plants respond differently to vadose zone salinity, thus altering the salinity through feedback. Using mathematical models, we show how the self-reinforcing feedback, together with physical template, controls the ecotones between halophytic and freshwater communities. Regions of bistability along environmental gradients of salinity have the potential for large-scale vegetation shifts following pulse disturbances such as hurricane tidal surges in Florida, or tsunamis in other regions. The size of the region of bistability can be large for low-lying coastal habitat due to the saline water table, which extends inland due to salinity intrusion. We suggest coupling ecological and hydrologic processes as a framework for future studies.

  1. Assessing radiation impact at a protected coastal sand dune site: an intercomparison of models for estimating the radiological exposure of non-human biota

    International Nuclear Information System (INIS)

    This paper presents the application of three publicly available biota dose assessment models (the ERICA Tool, R and D128/SP1a and RESRAD-BIOTA) to an assessment of the Drigg coastal sand dunes. Using measured 90Sr, 99Tc, 137Cs, 238Pu, 239+240Pu and 241Am activity concentrations in sand dune soil, activity concentration and dose rate predictions are made for a range of organisms including amphibians, birds, invertebrates, mammals, reptiles, plants and fungi. Predicted biota activity concentrations are compared to measured data where available. The main source of variability in the model predictions is the transfer parameters used and it is concluded that developing the available transfer databases should be a focus of future research effort. The value of taking an informed user approach to investigate the way in which models may be expected to be applied in practice is highlighted and a strategy for the future development of intercomparison exercises is presented.

  2. Optimization of the microwave-assisted saponification and extraction of organic pollutants from marine biota using experimental design and artificial neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Borges, J.; Rodriques-Delgado, M.A.; Garcia-Montelongo, F.J. [Laguna Univ., Tenerife (Spain). Dept. of Analytical Chemistry, Nutrition and Food Science

    2006-02-15

    Several improvements in sample pretreatment for the determination of organic pollutants (i.e. n-alkanes, polycyclic aromatic hydrocarbons, PAHs) in marine biota (mussels) are presented. The use of liquid nitrogen and homogenization of the samples are shown to be an alternative to the time consuming liophilization step required for the analysis of biota samples. Microwave-assisted hydrolysis and extraction are combined to isolate organic pollutants (19 n-alkanes and 27 PAHs) from biota matrices. Experimental design (ES) and artificial neural networks (ANNs) were used to optimize the experimental conditions. NIST-CRM 2978 was used to test the validity of the developed method which shows a good agreement with certified values. (orig.)

  3. Assessing radiation impact at a protected coastal sand dune site: an intercomparison of models for estimating the radiological exposure of non-human biota.

    Science.gov (United States)

    Wood, Michael D; Beresford, Nicholas A; Barnett, Catherine L; Copplestone, David; Leah, Richard T

    2009-12-01

    This paper presents the application of three publicly available biota dose assessment models (the ERICA Tool, R&D128/SP1a and RESRAD-BIOTA) to an assessment of the Drigg coastal sand dunes. Using measured (90)Sr, (99)Tc, (137)Cs, (238)Pu, (239+240)Pu and (241)Am activity concentrations in sand dune soil, activity concentration and dose rate predictions are made for a range of organisms including amphibians, birds, invertebrates, mammals, reptiles, plants and fungi. Predicted biota activity concentrations are compared to measured data where available. The main source of variability in the model predictions is the transfer parameters used and it is concluded that developing the available transfer databases should be a focus of future research effort. The value of taking an informed user approach to investigate the way in which models may be expected to be applied in practice is highlighted and a strategy for the future development of intercomparison exercises is presented. PMID:19447531

  4. Methylmercury Bioaccumulation in Rice and Wetland Biota: employing integrated indices of processes that drive methylmercury risk

    Science.gov (United States)

    Eagles-Smith, C.; Ackerman, J.; Windham-Myers, L.; Fleck, J.

    2013-12-01

    Wetlands often are associated with elevated methylmercury (MeHg) production and food web bioaccumulation, making them potentially important sources of Hg to surrounding waters and to wetland-dependent fish and wildlife. However, the cycling of MeHg through wetlands can vary markedly with wetland type. Agricultural wetlands such as rice fields can exhibit particularly pronounced MeHg concentrations and bioaccumulation because their biogeochemical, hydrological, and ecological characteristics facilitate the conversion of inorganic mercury (Hg) to MeHg. Rice fields are characterized by a series of seasonal extreme wetting and drying cycles, sulfate-containing fertilizers, and high levels of labile organic carbon, all of which are key processes in the Hg cycle. Rice fields comprise approximately 20% of freshwater habitats and 11% of cultivated land area globally, providing critical wildlife habitat while offering substantial economic, human health, and ecosystem benefits. Thus, there is strong impetus to better understand the drivers of Hg cycling in rice fields and to develop useful management approaches for minimizing Hg risk associated with rice agriculture without compromising rice production. We examined the role of rice wetlands on MeHg bioaccumulation through foodwebs by employing biosentinel caged fish as integrators of MeHg cycling processes. With experimental field studies in California's Central Valley, we placed biosentinel fishes into nine rice wetlands that were subjected to three different harvest strategies, and into nine managed wetlands that encompassed three different hydrological regimes. We simultaneously measured a suite of biogeochemical processes in surface water, sediment, and pore water in order to link the response in fish Hg bioaccumulation with within-field processes that regulate MeHg cycling. Our preliminary results indicate that fish Hg concentrations were 1.6 times higher in rice wetlands than in managed wetlands. Additionally, fish Hg

  5. A freshwater biodiversity hotspot under pressure - assessing threats and identifying conservation needs for ancient Lake Ohrid

    Science.gov (United States)

    Kostoski, G.; Albrecht, C.; Trajanovski, S.; Wilke, T.

    2010-12-01

    Immediate conservation measures for world-wide freshwater resources are of eminent importance. This is particularly true for so-called ancient lakes. While these lakes are famous for being evolutionary theatres, often displaying an extraordinarily high degree of biodiversity and endemism, in many cases these biota are also experiencing extreme anthropogenic impact. Lake Ohrid, a major European biodiversity hotspot situated in a trans-frontier setting on the Balkans, is a prime example for a lake with a magnitude of narrow range endemic taxa that are under increasing anthropogenic pressure. Unfortunately, evidence for a "creeping biodiversity crisis" has accumulated over the last decades, and major socio-political changes have gone along with human-mediated environmental changes. Based on field surveys, monitoring data, published records, and expert interviews, we aimed to (1) assess threats to Lake Ohrids' (endemic) biodiversity, (2) summarize existing conservation activities and strategies, and (3) outline future conservation needs for Lake Ohrid. We compiled threats to both specific taxa (and in cases to particular species) as well as to the lake ecosystems itself. Major conservation concerns identified for Lake Ohrid are: (1) watershed impacts, (2) agriculture and forestry, (3) tourism and population growth, (4) non-indigenous species, (5) habitat alteration or loss, (6) unsustainable exploitation of fisheries, and (7) global climate change. Among the major (well-known) threats with high impact are nutrient input (particularly of phosphorus), habitat conversion and silt load. Other threats are potentially of high impact but less well known. Such threats include pollution with hazardous substances (from sources such as mines, former industries, agriculture) or climate change. We review and discuss institutional responsibilities, environmental monitoring and ecosystem management, existing parks and reserves, biodiversity and species measures, international

  6. Are standard tests sensitive enough to evaluate effects of human pharmaceuticals in aquatic biota? Facing changes in research approaches when performing risk assessment of drugs.

    Science.gov (United States)

    Aguirre-Martínez, G V; Owuor, M A; Garrido-Pérez, C; Salamanca, M J; Del Valls, T A; Martín-Díaz, M L

    2015-02-01

    Nowadays, the presence of pharmaceutical products in aquatic environments is not only common, but is also of significant concern regarding the adverse effect they may produce to aquatic biota. In order to determine the adverse effects of caffeine (CAF), ibuprofen (IBU), carbamazepine (CBZ) and novobiocin (NOV), at environmental occurring concentrations, standardized endpoints applied in current guidelines were evaluated in four organisms including bioluminescence response in Vibrio fischeri, growth inhibition in Isochrysis galbana (marine water) and Pseudokirchneriella subcapitata (fresh water) and fertilization and embryo-larval development in Paracentrotus lividus. To reach this aim bioassays were implemented by exposing organisms to water spiked with drugs dissolved in DMSO (0.001% v/v). Risk characterization was performed, calculating the environmental impact of drugs by calculating environmental concentration and predicted no effect concentration ratio (MEC/PNEC). Results indicate that acute toxicity was found above environmental concentrations in the order of mg L(-1) for bacteria bioluminescence, microalgae growth inhibition and sea urchin fertilization. However, teratogenicity was observed on sea urchin after exposure to environmental concentrations of drugs at 0.00001 mg L(-1); at this concentration CBZ and IBU were found to reduce significantly the embryo-larval development compared to controls (p<0.01). The risk calculated for selected drugs suggested they are harmless for aquatic environment except when applying the embryo-larval development endpoint. Endpoints applied in this study showed the necessity of using more sensitive responses, when assessing risk of pharmaceuticals in aquatic environments, since endpoints applied in current guidelines may not be suitable.

  7. No difference in the competitive ability of introduced and native Trifolium provenances when grown with soil biota from their introduced and native ranges.

    Science.gov (United States)

    Shelby, Natasha; Hulme, Philip E; van der Putten, Wim H; McGinn, Kevin J; Weser, Carolin; Duncan, Richard P

    2016-01-01

    The evolution of increased competitive ability (EICA) hypothesis could explain why some introduced plant species perform better outside their native ranges. The EICA hypothesis proposes that introduced plants escape specialist pathogens or herbivores leading to selection for resources to be reallocated away from defence and towards greater competitive ability. We tested the hypothesis that escape from soil-borne enemies has led to increased competitive ability in three non-agriculturalTrifolium(Fabaceae) species native to Europe that were introduced to New Zealand in the 19th century.Trifoliumperformance is intimately tied to rhizosphere biota. Thus, we grew plants from one introduced (New Zealand) and two native (Spain and the UK) provenances for each of three species in pots inoculated with soil microbiota collected from the rhizosphere beneath conspecifics in the introduced and native ranges. Plants were grown singly and in competition with conspecifics from a different provenance in order to compare competitive ability in the presence of different microbial communities. In contrast to the predictions of the EICA hypothesis, we found no difference in the competitive ability of introduced and native provenances when grown with soil microbiota from either the native or introduced range. Although plants from introduced provenances of two species grew more slowly than native provenances in native-range soils, as predicted by the EICA hypothesis, plants from the introduced provenance were no less competitive than native conspecifics. Overall, the growth rate of plants grown singly was a poor predictor of their competitive ability, highlighting the importance of directly quantifying plant performance in competitive scenarios, rather than relying on surrogate measures such as growth rate. PMID:26969431

  8. Assessing and managing freshwater ecosystems vulnerable to global change

    Science.gov (United States)

    Angeler, David G.; Allen, Craig R.; Birge, Hannah E.; Drakare, Stina; McKie, Brendan G.; Johnson, Richard K.

    2014-01-01

    Freshwater ecosystems are important for global biodiversity and provide essential ecosystem services. There is consensus in the scientific literature that freshwater ecosystems are vulnerable to the impacts of environmental change, which may trigger irreversible regime shifts upon which biodiversity and ecosystem services may be lost. There are profound uncertainties regarding the management and assessment of the vulnerability of freshwater ecosystems to environmental change. Quantitative approaches are needed to reduce this uncertainty. We describe available statistical and modeling approaches along with case studies that demonstrate how resilience theory can be applied to aid decision-making in natural resources management. We highlight especially how long-term monitoring efforts combined with ecological theory can provide a novel nexus between ecological impact assessment and management, and the quantification of systemic vulnerability and thus the resilience of ecosystems to environmental change.

  9. Challenges of Freshwater Fisheries in Nepal: A Short Overview

    Directory of Open Access Journals (Sweden)

    Nawaraj Gautam

    2015-12-01

    Full Text Available Abundant freshwater resources originated from Himalayas and high geographical variations in Nepal are two factors which might be positive benefits to improve the aquaculture in land locked country. Low labor cost is also another plus point to get better management in fisheries sector. Freshwater fisheries in Nepal are mostly dominated by catch up fisheries of indigenous fish species available in rivers, lakes and paddy fields but exotic and sophisticated species been also introduced in small scales. Beside these, poly cultural pond fish farming is most viable. Carp fishes are the major species and uncontrolled unmanaged capture fisheries dominants over systematic aquaculture. Poor technological implementations, poor budgetary plan, not proper management strategies, lack of quality fish feed and fingerlins, lower market availability are some of the major challenges of Nepalese freshwater fisheries. Long-term sustainable plan, scientific and technological study on indigenous fish species, proper hygiene management and better disease control might improve the current aquaculture status of Nepal.

  10. New data on freshwater psammic Gastrotricha from Brazil

    Directory of Open Access Journals (Sweden)

    André Rinaldo Garraffoni

    2010-10-01

    Full Text Available Current knowledge of freshwater gastrotrich fauna from Brazil is underestimated as only two studies are available. The present communication is a taxonomic account of the first-ever survey of freshwater Gastrotricha in Minas Gerais State. Samplings were carried out yielding six species of three Chaetonotidae genera: Aspidiophorus cf. pleustonicus, Ichthydium cf. chaetiferum, Chaetonotus acanthocephalus, C. heideri, C. cf. succinctus, Chaetonotus sp., and also an undescribed species belonging to the genus Redudasys (incertae sedis: this is the first finding of specimens of Redudasys outside of original type locality. These preliminary observations suggest that the knowledge of the biodiversity of Gastrotricha in the Minas Gerais State, as well as in the whole Brazil, will certainly increase as further investigations are undertaken, and that freshwater Macrodasyida may be more common than previously thought.

  11. Influence of short term exposure of TBT on the male reproductive activity in freshwater prawn Macrobrachium rosenbergii (De Man).

    Science.gov (United States)

    Revathi, Peranandam; Iyapparaj, Palanisamy; Vasanthi, Lourduraj Arockia; Munuswamy, Natesan; Prasanna, Vimalanathan Arun; Pandiyarajan, Jayaraj; Krishnan, Muthukalingan

    2014-10-01

    In the present study, the effect of tributyltin (TBT) on the histopathological and hormonal changes during spermatogenesis in freshwater prawn Macrobrachium rosenbergii was documented. Three experimental concentrations such as 10, 100 and 1,000 ng/L were selected and exposed to prawns for 45 days. After TBT exposure, the reproductive activities like sperm count and sperm length were decreased when compared with control. Further, abnormal structure of the seminiferous tubule, decrease in spermatozoa concentration, diminution of the seminiferous tubule membrane and the abundance of spermatocytes in the testis were noticed in treated prawns. Interestingly, radioimmunoassay clearly revealed the reduction of testosterone level in TBT exposed groups. Thus, TBT has considerably reduced the level of testosterone and caused the impairment of spermatogenesis in the freshwater male prawn M. rosenbergii.

  12. Investigating salt and naphthenic acids interactions in the toxicity of oil sands process water to freshwater invertebrates

    International Nuclear Information System (INIS)

    The hot water extraction process used to produce bitumens from oil sands produces a large volume of oil sands process water (OSPW) that contain elevated concentrations of naphthenic acids (NA) and salts. Many oil sands reclamation projects are proposing the use of OSPW as part of reconstructed wetlands projects. This study investigated the toxicity of OSPW to freshwater invertebrates. The toxic interactions between NA and salinity on freshwater invertebrates were assessed. Bioassays with laboratory-cultured Ceriodaphnia dubia were conducted to determine the toxicity of OSPW from selected water bodies. The study showed that while the concentrations of NAs and salinity were elevated in OSPW waters that caused toxic responses, the concentrations of salinity ions varied greatly among the OSPW samples. Results of the study suggested that ion composition may be a factor in toxicity. Interactions between NAs and salinity were then assessed by performing bioassays with mixtures representing major ion combinations in OSPW.

  13. 2H and 18O Freshwater Isoscapes of Scotland

    Science.gov (United States)

    Meier-Augenstein, Wolfram; Hoogewerff, Jurian; Kemp, Helen; Frew, Danny

    2013-04-01

    Scotland's freshwater lochs and reservoirs provide a vital resource for sustaining biodiversity, agriculture, food production as well as for human consumption. Regular monitoring of freshwaters by the Scottish Environment Protection Agency (SEPA) fulfils legislative requirements with regards to water quality but new scientific methods involving stable isotope analysis present an opportunity combining these mandatory monitoring schemes with fundamental research to inform and deliver on current and nascent government policies [1] through gaining a greater understanding of Scottish waters and their importance in the context of climate change, environmental sustainability and food security. For example, 2H and 18O isoscapes of Scottish freshwater could be used to underpin research and its applications in: • Climate change - Using longitudinal changes in the characteristic isotope composition of freshwater lochs and reservoirs as proxy, isoscapes will provide a means to assess if and how changes in temperature and weather patterns might impact on precipitation patterns and amount. • Scottish branding - Location specific stable isotope signatures of Scottish freshwater have the potential to be used as a tool for provenancing and thus protecting premium Scottish produce such as Scottish beef, Scottish soft fruit and Scottish Whisky. During 2011 and 2012, with the support of SEPA more than 110 samples from freshwater lochs and reservoirs were collected from 127 different locations across Scotland including the Highlands and Islands. Here we present the results of this sampling and analysis exercise isotope analyses in form of 2H and 18O isoscapes with an unprecedented grid resolution of 26.5 × 26.5 km (or 16.4 × 16.4 miles). [1] Adaptation Framework - Adapting Our Ways: Managing Scotland's Climate Risk (2009): Scotland's Biodiversity: It's in Your Hands - A strategy for the conservation and enhancement of biodiversity in Scotland (2005); Recipe For Success - Scotland

  14. Patterns of Freshwater Species Richness, Endemism, and Vulnerability in California.

    Directory of Open Access Journals (Sweden)

    Jeanette K Howard

    Full Text Available The ranges and abundances of species that depend on freshwater habitats are declining worldwide. Efforts to counteract those trends are often hampered by a lack of information about species distribution and conservation status and are often strongly biased toward a few well-studied groups. We identified the 3,906 vascular plants, macroinvertebrates, and vertebrates native to California, USA, that depend on fresh water for at least one stage of their life history. We evaluated the conservation status for these taxa using existing government and non-governmental organization assessments (e.g., endangered species act, NatureServe, created a spatial database of locality observations or distribution information from ~400 data sources, and mapped patterns of richness, endemism, and vulnerability. Although nearly half of all taxa with conservation status (n = 1,939 are vulnerable to extinction, only 114 (6% of those vulnerable taxa have a legal mandate for protection in the form of formal inclusion on a state or federal endangered species list. Endemic taxa are at greater risk than non-endemics, with 90% of the 927 endemic taxa vulnerable to extinction. Records with spatial data were available for a total of 2,276 species (61%. The patterns of species richness differ depending on the taxonomic group analyzed, but are similar across taxonomic level. No particular taxonomic group represents an umbrella for all species, but hotspots of high richness for listed species cover 40% of the hotspots for all other species and 58% of the hotspots for vulnerable freshwater species. By mapping freshwater species hotspots we show locations that represent the top priority for conservation action in the state. This study identifies opportunities to fill gaps in the evaluation of conservation status for freshwater taxa in California, to address the lack of occurrence information for nearly 40% of freshwater taxa and nearly 40% of watersheds in the state, and to

  15. Accumulation of transuranic elements in the aquatic biota of the Belarusian sector of contaminated area near the Chernobyl nuclear power plant - Accumulation of transuranic elements in aquatic biota of Belarusian sector of contaminated area of Chernobyl nuclear power plant

    Energy Technology Data Exchange (ETDEWEB)

    Golubev, Alexander; Mironov, Vladislav [International Sakharov Environmental University. Box 220070, 23 Dolgobrodskaya Street, Minsk, 220070 (Belarus)

    2014-07-01

    The evolution of nuclear contamination of Belarus territory after Chernobyl accident includes the four stages: 1. Iodine-neptunium stage, caused mainly by short-lived radionuclides {sup 131}I, {sup 239}Np and others with a half-life period of several weeks; II. Intermediate stage, caused by radionuclides with a half-life period of a year ({sup 144}Ce, {sup 106}Ru, {sup 134}Cs, etc.); III. Strontium-cesium stage, caused by {sup 90}Sr and {sup 137}Cs with a half-life period of about 30 years; IV. Plutonium-americium, caused by long-lived α-emitting radionuclides {sup 241}Am (period of half-life of 432 years) and {sup 239+240}Pu, having high radio and chemo-toxicity. According to forecasts, activity of {sup 241}Am to 2050 year will increase by 2.5 times and it will be the most important dose-related factor for the aquatic biota within the Chernobyl accident zone. In 2002 - 2008 years we have studied the accumulation of trans-uranic elements (TUE, {sup 241}Am, {sup 239+240}Pu) in basic components of water body ecosystems within the Chernobyl zone - non-flowing Perstok Lake, weak-flowing Borschevka flooding and small Braginka River. Among investigated components are water, bottom sediments, submerged macrophytes (Ceratophyllum submersum, Hydrocharis morsus-ranae, Lemna minor, Nuphar lutea, Stratiotes aloides), emergent macrophytes (Typha spp.), shellfish and fish. In the soil cover in the vicinity of the Perstok Lake activity of {sup 241}Am at present is equivalent to 300 - 600 Bq.kg{sup -1}, that is the basic source of its income to the lake. Radionuclides mobility in the water environment is higher than in the soil, that facilitates the rapid incorporation of {sup 241}Am to the trophic nets of water bodies and its removal by near-water animals in the terrestrial biotopes, including outside Chernobyl zone. Thus, the activity of {sup 241}Am in bottom sediments in the Perstok Lake and Borschevka flooding in 2008 year reach respectively 324 and 131 Bq.kg{sup -1}, and the

  16. Towards a universal sampling protocol for soil biotas in the humid tropics Em direção a um protocolo universal de amostragem de biotas do solo nos trópicos úmidos

    Directory of Open Access Journals (Sweden)

    David Edward Bignell

    2009-08-01

    Full Text Available This paper reviews the methods for the inventory of below-ground biotas in the humid tropics, to document the (hypothesized loss of soil biodiversity associated with deforestation and agricultural intensification at forest margins. The biotas were grouped into eight categories, each of which corresponded to a major functional group considered important or essential to soil function. An accurate inventory of soil organisms can assist in ecosystem management and help sustain agricultural production. The advantages and disadvantages of transect-based and grid-based sampling methods are discussed, illustrated by published protocols ranging from the original "TSBF transect", through versions developed for the alternatives to Slash-and-Burn Project (ASB to the final schemes (with variants adopted by the Conservation and Sustainable Management of Below-ground Biodiversity Project (CSM-BGBD. Consideration is given to the place and importance of replication in below-ground biological sampling and it is argued that the new sampling protocols are inclusive, i.e. designed to sample all eight biotic groups in the same field exercise; spatially scaled, i.e. provide biodiversity data at site, locality, landscape and regional levels, and link the data to land use and land cover; and statistically robust, as shown by a partial randomization of plot locations for sampling.Este trabalho faz uma revisão dos métodos de inventariado da biota edáfica nos trópicos úmidos para documentar a (hipotética perda de biodiversidade do solo associada ao desmatamento e à intensificação agrícola nas margens de florestas. A biota foi agrupada em oito categorias, cada uma correspondente a um grande grupo funcional considerado importante ou essencial para a função do solo. Um inventário cuidadoso dos organismos do solo pode auxiliar a gestão de ecossistemas e a sustentabilidade da produção agrícola. As vantagens e desvantagens de métodos de amostragem baseados em

  17. RECOVERY OF FRESHWATER STORED IN SALINE AQUIFERS IN PENINSULAR FLORIDA.

    Science.gov (United States)

    Merritt, Michael L.

    1986-01-01

    Subsurface freshwater storage has been operationally tested at seven sites in central and south Florida. Injection was into a high chloride water aquifer at six sites, and into a high sulfate water aquifer at the seventh. Recovery efficiency has ranged from 0 to 75 percent in high chloride water aquifers, and has exceeded 100 percent in the high sulfate water aquifer. Computer modeling techniques were used to examine the geohydrologic, design, and management factors governing the recovery efficiency of subsurface freshwater storage. The modeling approach permitted many combinations of geohydrologic and operational conditions to be studied at relatively low cost.

  18. Guanling Biota: A Marker of Triassic Biotic Recovery from the end-Permian Extinction in the Ancient Guizhou Sea

    Institute of Scientific and Technical Information of China (English)

    JIANG Dayong; Ryosuke MOTANI; LI Chun; HAO Weicheng; SUN Yuanlin; SUN Zuoyu; Lars SCHMITZ

    2005-01-01

    After a slow recovery from the end-Permian extinction during the Early Triassic and rapid radiation in the Middle Triassic, evolution of organisms reached a new peak phase in the Late Triassic. The Guanling Biota from the Wayao Member (conodont Paragondolella polygnathiformis Zone), Falang Formation, Xinpu, Guanling County, Guizhou Province, southwestern China corresponds to this peak that marks the full recovery from the end-Permian extinction of marine ecosystems. The biota is of high diversity, containing well preserved and completely articulated skeletons of vertebrates comprising marine reptiles, fishes, and invertebrates including crinoids, ammonites, bivalves, and other fossils,and is one of the best examples of marine ecosystem records in life history. The fossil marine reptiles and crinoids are most significant in this biota, especially the marine reptiles, which provide an important link between the Triassic Pacific and Tethys, and between Triassic basal forms and the Jurassic-Cretaceous marine top predators. The most remarkable fossils are the large completely articulated ichthyosaur skeletons up to and more than 10 m, and the first recorded thalattosaurs and placodonts in China. Following our review, of the 17 named reptilian taxa the eight listed here are considered to be valid: three ichthyosaurs (Qianichthyosaurus zhoui Li, 1999; Guizhouichthyosaurus tangae Cao and Luo in Yin et al.,2000, Guanlingsaurus liangae Yin in Yin et al., 2000), three thalattosaurs (Anshunsaurus huangguoshuensis Liu, 1999,Xinpusaurus suni Yin in Yin et al., 2000, Xinpusaurus kohi Jiang et al., 2004), and two placodonts (Sinocyamodus xinpuensis Li, 2000, Psephochelys polyosteoderma Li and Rieppel, 2002). Mixosaurus guanlingensis Cao in Yin et al.,2000 might be a junior synonym of Qianichthyosaurus zhoui Li, 1999, and Cymbospondylus asiaticus Li and You, 2002and Panjiangsaurus epicharis Chen and Cheng, 2003 might be junior synonyms of Guizhouichthyosaurus tangae Cao and Luo in

  19. Impact of changing DOC concentrations on the potential distribution of acid sensitive biota in a boreal stream network

    Directory of Open Access Journals (Sweden)

    H. Laudon

    2007-09-01

    Full Text Available DOC concentrations have increased in many surface waters in Europe and North America over the past few decades. As DOC exerts a strong influence on pH this DOC increase could have detrimental effects on acid sensitive biota in many streams and lakes. To investigate the potential implications of changes in the DOC concentration on stream water biota, we have used a mesoscale boreal stream network in northern Sweden as a case study. The network was sampled for stream water chemistry at 60 locations during both winter base flow and spring flood periods, representing the extremes experienced annually in these streams both in terms of discharge and acidity. The effect of changing DOC on pH was modeled for all sampling locations using an organic acid model, with input DOC concentrations for different scenarios adjusted by between –30% and +50% from measured present concentrations. The resulting effect on pH was then used to quantify the proportion of stream length in the catchment with pH below the acid thresholds of pH 5.5 and pH 5.0. The results suggest that a change in stream water DOC during base flow would have only a limited effect on pH and hence on the stream length with pH below the acid thresholds. During the spring flood on the other hand a change in DOC would strongly influence pH and the stream length with pH below the acid thresholds. For example an increase in DOC concentration of 30% at all sites would increase the proportion of stream length with pH below 5.5 from 37% to 65%, and the proportion of stream length with pH below 5.0 would increase from 18% to 27%. The results suggest that in poorly-buffered high DOC waters, even a marginal change in the DOC concentration could impact acid sensitive biota in a large portion of the aquatic landscape.

  20. Effects of cadmium stress and sorption kinetics on tropical freshwater periphytic communities in indoor mesocosm experiments

    Energy Technology Data Exchange (ETDEWEB)

    Bere, Taurai, E-mail: taubere@yahoo.com [Instituto Internacional de Ecologia, Rua Bento Carlos, 750, Centro, Sao Carlos, Sao Paulo (Brazil); Universidade Federal De Sao Carlosm, Programa de Pos-Graduacao em Ecologia e Recursos Naturais, Rodovia Washington Luis, km 235, SP-310, Sao Carlos, Sao Paulo (Brazil); Tundisi, Jose Galizia [Instituto Internacional de Ecologia, Rua Bento Carlos, 750, Centro, Sao Carlos, Sao Paulo (Brazil)

    2012-08-15

    Understanding the cause and effect relationship between stressors and biota is crucial for the effective management, restoration and preservation of aquatic systems. The objective of the present study was to assess the effects of five Cd concentrations on tropical periphyton community growth, Cd accumulation kinetics, as well as the effects of Cd on diatom community structure and composition. Natural periphyton communities were transferred to artificial stream chambers and exposed to Cd concentrations of 0.005, 0.01, 0.03, 0.05 and 0.1 mg.L{sup -1}. Metal accumulation (total and intracellular) in biofilms, dry weight and ash-free dry mass, growth rate, algal cell density and diatom community composition were analysed on samples collected after 1, 2 and 4 weeks of colonization. Periphyton growth and development were significantly lowered by Cd concentrations > 0.03 mg.L{sup -1}. High Cd accumulation capacity by periphyton was demonstrated with total and intracellular Cd content in biofilms reflecting the effects of concentrations of Cd in the culture media and exposure duration. Total and intracellular Cd content generally increased in treatments in the order 0.005 < 0.01 < 0.03 < 0.05 < 0.1 mg.L{sup -1} at any sampling time with increasing level of accumulated Cd with duration of exposure in all the systems. Shifts in species composition (development of more resistant species like Achnanthidium minutissimum and reduction of sensitive ones like Diatoma vulgare, Navicula viridula and Navicula cryptocephala), decreases in species richness and diversity and morphological alterations (deformities) of diatom cells with increasing Cd concentration and exposure duration were observed. The results give valuable information on Cd impact of freshwater biofilms. -- Highlights: Black-Right-Pointing-Pointer We investigated toxicity and sorption kinetics of Cd on periphyton communities. Black-Right-Pointing-Pointer [Cd] > 0.03 mg.L{sup -1} lowers growth. Black

  1. Exposure dose response relationships of the freshwater bivalve Hyridella australis to cadmium spiked sediments

    Energy Technology Data Exchange (ETDEWEB)

    Marasinghe Wadige, Chamani P.M., E-mail: chamani.marasinghe.wadige@canberra.edu.au; Maher, William A.; Taylor, Anne M.; Krikowa, Frank

    2014-07-01

    Highlights: • The exposure–dose–response approach was used to assess cadmium exposure and toxicity. • Accumulated cadmium in H. australis reflected the sediment cadmium exposure. • Spill over of cadmium into the biologically active pool was observed. • Increased cadmium resulted in measurable biological effects. • H. australis has the potential to be a cadmium biomonitor in freshwater environments. - Abstract: To understand how benthic biota may respond to the additive or antagonistic effects of metal mixtures in the environment it is first necessary to examine their responses to the individual metals. In this context, laboratory controlled single metal-spiked sediment toxicity tests are useful to assess this. The exposure–dose–response relationships of Hyridella australis to cadmium-spiked sediments were, therefore, investigated in laboratory microcosms. H. australis was exposed to individual cadmium spiked sediments (<0.05 (control), 4 ± 0.3 (low) and 15 ± 1 (high) μg/g dry mass) for 28 days. Dose was measured as cadmium accumulation in whole soft body and individual tissues at weekly intervals over the exposure period. Dose was further examined as sub-cellular localisation of cadmium in hepatopancreas tissues. The biological responses in terms of enzymatic and cellular biomarkers were measured in hepatopancreas tissues at day 28. H. australis accumulated cadmium from spiked sediments with an 8-fold (low exposure organisms) and 16-fold (high exposure organisms) increase at day 28 compared to control organisms. The accumulated tissue cadmium concentrations reflected the sediment cadmium exposure at day 28. Cadmium accumulation in high exposure organisms was inversely related to the tissue calcium concentrations. Gills of H. australis showed significantly higher cadmium accumulation than the other tissues. Accumulated cadmium in biologically active and biologically detoxified metal pools was not significantly different in cadmium exposed

  2. Incidence of the leech Actinobdella pediculata on freshwater drum in Lake Erie

    Science.gov (United States)

    Bur, Michael T.

    1994-01-01

    Actinobdella pediculata (Glossiphoniidae), a freshwater leech, was found attached to freshwater drum (Aplodinotus grunniens) from western Lake Erie during 1991 through 1993. The animal was first observed during routine examinations of freshwater drum collected in May 1991. The leeches were usually attached to the inside, lower portion of the opercula near the isthmus. Incidence of attachment increased with freshwater drum age and length. No noticeable adverse effects on the fish from attachment by the leech were noted.

  3. Highest PBDE levels (max 63 ppm) yet found in biota measured in seabird eggs from San Francisco Bay

    Energy Technology Data Exchange (ETDEWEB)

    She, J.; Holden, A.; Tanner, M.; Sharp, M.; Hooper, K. [Department of Toxic Substances Control, Berkeley, CA (United States). Hazardous Materials Lab.; Adelsbach, T. [Environmental Contaminants Division, Sacramento Fish and Wildlife Office, US Fish and Wildlife Service, Sacramento, CA (United States)

    2004-09-15

    High levels of polybrominated diphenylethers (PBDEs) have been found in humans and wildlife from the San Francisco Bay Area, with levels in women among the highest in the world, and levels in piscivorous seabird eggs at the ppm level. Seabirds are useful for monitoring and assessing ecosystem health at various times and places because they occupy a high trophic level in the marine food web, are long-lived, and are generally localized near their breeding and non-breeding sites. In collaboration with the US Fish and Wildlife Services (USFWS), we are carrying out a three-year investigation of dioxin, PCB and PBDE levels in eggs from fish-eating seabirds. Year 1 (2002) PBDE measurements from 73 bird eggs were reported at Dioxin2003. Year 2 (2003) PBDE measurements from 45 samples are presented in this report. The highest PBDE level measured in eggs was 63 ppm, lipid, which is the highest PBDE level, yet reported in biota.

  4. Contribution to the lichen biota of the Stawy Milickie nature reserve and its adjacent area (Lower Silesia, southwestern Poland

    Directory of Open Access Journals (Sweden)

    Edyta Kaźmierska

    2016-07-01

    Full Text Available The paper presents the results of lichenological investigations conducted in the eastern part of the Stawy Milickie nature reserve and its buffer zone (Barycz Valley, southwestern Poland. The study area is a famous waterfowl refuge, consisting of several fishpond complexes, together with adjacent forests, meadows, and villages. In total 72 lichen taxa were recorded, growing on bark and branches of trees and shrubs, stumps, wood, soil, and anthropogenic rock substrates (mortar, concrete, bricks, etc.. Six species, namely Evernia prunastri, Flavoparmelia caperata, Hypogymnia tubulosa, Parmelina tiliacea, Physconia distorta, and Pleurosticta acetabulum, are threatened in Poland. As represented by single young thalli, they indicate the recent improvement of environmental conditions. The lichen biota of the study area is typical for the lowland regions of western and southwestern Poland.

  5. Changes in environmental conditions as the cause of the marine biota Great Mass Extinction at the Triassic-Jurassic boundary

    Science.gov (United States)

    Barash, M. S.

    2016-02-01

    In the interval of the Triassic-Jurassic boundary, 80% of the marine species became extinct. Four main hypotheses about the causes of this mass extinction are considered: volcanism, climatic oscillations, sea level variations accompanied by anoxia, and asteroid impact events. The extinction was triggered by an extensive flooding of basalts in the Central Atlantic Magmatic Province. Furthermore, a number of meteoritic craters have been found. Under the effect of cosmic causes, two main sequences of events developed on the Earth: terrestrial ones, leading to intensive volcanism, and cosmic ones (asteroid impacts). Their aftermaths, however, were similar in terms of the chemical compounds and aerosols released. As a consequence, the greenhouse effect, dimming of the atmosphere (impeding photosynthesis), ocean stagnation, and anoxia emerged. Then, biological productivity decreased and food chains were destroyed. Thus, the entire ecosystem was disturbed and a considerable part of the biota became extinct.

  6. The aquatic and semiaquatic biota in Miocene amber from the Campo LA Granja mine (Chiapas, Mexico): Paleoenvironmental implications

    Science.gov (United States)

    Serrano-Sánchez, María de Lourdes; Hegna, Thomas A.; Schaaf, Peter; Pérez, Liseth; Centeno-García, Elena; Vega, Francisco J.

    2015-10-01

    Amber from the Campo La Granja mine in Chiapas, Mexico, is distinct from other sources of amber in Chiapas. Campo La Granja amber has distinct layers created by successive flows of resin with thin layers of sand on most surfaces. Aquatic and semi-aquatic arthropods are commonly found. Together these pieces of evidence suggest an estuarine environment similar to modern mangrove communities. The aquatic crustaceans are the most intriguing aspect of the biota. A large number of ostracods have been found in the amber-many with their carapaces open, suggesting that they were alive and submerged in water at the time of entombment. The only known examples of brachyuran crabs preserved in amber are found in the Campo La Granja amber. Amphipods, copepods, isopods, and tanaids are also members of the crustacean fauna preserved in amber.

  7. Downstream cumulative effects of land use on freshwater communities

    Science.gov (United States)

    Kuglerová, L.; Kielstra, B. W.; Moore, D.; Richardson, J. S.

    2015-12-01

    Many streams and rivers are subject to disturbance from intense land use such as urbanization and agriculture, and this is especially obvious for small headwaters. Streams are spatially organized into networks where headwaters represent the tributaries and provide water, nutrients, and organic material to the main stems. Therefore perturbations within the headwaters might be cumulatively carried on downstream. Although we know that the disturbance of headwaters in urban and agricultural landscapes poses threats to downstream river reaches, the magnitude and severity of these changes for ecological communities is less known. We studied stream networks along a gradient of disturbance connected to land use intensity, from urbanized watersheds to watersheds placed in agricultural settings in the Greater Toronto Area. Further, we compared the patterns and processes found in the modified watershed to a control watershed, situated in a forested, less impacted landscape. Preliminary results suggest that hydrological modifications (flash floods), habitat loss (drainage and sewer systems), and water quality issues of small streams in urbanized and agricultural watersheds represent major disturbances and threats for aquatic and riparian biota on local as well as larger spatial scales. For example, communities of riparian plants are dominated by species typical of the land use on adjacent uplands as well as the dominant land use on the upstream contributing area, instead of riparian obligates commonly found in forested watersheds. Further, riparian communities in disturbed environments are dominated by invasive species. The changes in riparian communities are vital for various functions of riparian vegetation. Bank erosion control is suppressed, leading to severe channel transformations and sediment loadings in urbanized watersheds. Food sources for instream biota and thermal regimes are also changed, which further triggers alterations of in-stream biological communities

  8. Efectos de la biota edáfica en las interacciones planta-insecto a nivel foliar

    Directory of Open Access Journals (Sweden)

    E. de la Peña

    2009-01-01

    Full Text Available A pesar de la inmensa diversidad de especies que habitan en el suelo y de la importancia funcional que tiene la biota edáfica tanto a nivel de comunidad como de ecosistema, la teoría ecológica ha tenido tradicionalmente sólo en cuenta las interacciones que ocurren en la parte aérea de las plantas. Recientemente esta situación ha cambiado y durante los últimos diez años se han publicado numerosos estudios que destacan la importancia que tienen las interacciones bióticas entre plantas y organismos edáficos sobre diferentes procesos que se dan enla parte aérea. Estos estudios han demostrado que las interacciones que se dan entre las raíces y los herbívoros edáficos, los hongos mutualistas y la flora microbiana, tienen efecto no sólo en el crecimiento de las plantas sino también en niveles tróficos superiores como son los herbívoros foliares, parasitoides, hiperparasitoides y polinizadores. En este artículo se hace una breve revisión de los mecanismos fundamentales que median la relación entre la biota edáfica y las interacciones bióticas de la parte aérea. Por último, se proponen abordajes complementarios como son la utilización de modelos espaciales y el estudio de estas interacciones desde una perspectiva evolutiva.

  9. Host diversity and latitude drive trematode diversity patterns in the European freshwater fauna

    NARCIS (Netherlands)

    Thieltges, D.W.; Hof, C.; Dehling, D.M.; Brändle, M.; Brändl, R.; Poulin, R.

    2011-01-01

    Aim We investigated the relationship between host and parasite diversity as well as latitudinal gradients in parasite diversity on a continental scale in European freshwater trematodes.
    Location European freshwaters.
    Methods We extracted distributional data for 564 freshwater trematodes across

  10. Lysogenic infection in sub-tropical freshwater cyanobacteria cultures and natural blooms

    NARCIS (Netherlands)

    L.M. Steenhauer; P.C. Pollard; C.P.D. Brussaard; C. Säwström

    2014-01-01

    Lysogeny has been reported for a few freshwater cyanobacteria cultures, but it is unknown how prevalent it is in freshwater cyanobacteria in situ. Here we tested for lysogeny in (a) cultures of eight Australian species of subtropical freshwater cyanobacteria; (b) seven strains of one species: Cylind

  11. MOIRA: a computerised decision support system for the restoration of radionuclide contaminated freshwater ecosystems

    International Nuclear Information System (INIS)

    The radiation dose resulting from contamination of freshwater ecosystems due to the release of radioactive substances into the environment may be reduced by applying suitable countermeasures. The options for intervention are wide-ranging and can be broadly grouped into three main categories: chemical, physical and social countermeasures. In some cases, a combination of actions -or even the no action- may be the optimal strategy. Despite their benefits, intervention strategies may have detrimental effects of economic, ecological and social nature. Thus, it is of paramount importance to assess, by objective criteria, the global cost-benefit balance of different options. The MOIRA project (A MOdel based computerised system for management support to Identity optimal remedial strategies for Restoring radionuclide contaminated Aquatic ecosystems, European Commission contract FI4P-CT96-0036) has developed a user-friendly, computerised tool that will allow decision makers to choose optimal intervention strategies for freshwater ecosystems with different contamination scenarios. To achieve that goal, the MOIRA software system -apart from a user-friendly interface- incorporates several innovative aspects: - eographical information system (GIS) and databases to get to get the values of the model parameters at different locations in Europe. - redictive ecosystem models for the behaviour of radionuclides (namely Cs-137 and Sr-90) in catchments, lakes and rivers, complemented with models of the effect of the countermeasures on the environmental contamination levels. These models are based on an extensive use of aggregate parameters' that summarise, in single quantities, the effects of a variety of environmental processes. Methods for critical model testing, sensitivity and uncertainty analyses have been applied to them getting a high reliability. - cosystem index (EI) to handle the influence chemical remedial measures may have on the structure, reproduction and biomass of key

  12. Ecotoxicological effect of sublethal exposure to zinc oxide nanoparticles on freshwater snail Biomphalaria alexandrina.

    Science.gov (United States)

    Fahmy, Sohair R; Abdel-Ghaffar, Fathy; Bakry, Fayez A; Sayed, Dawlat A

    2014-08-01

    Freshwater snails are used as sensitive biomarkers of aquatic ecosystem pollution. The potential impacts of zinc oxide nanoparticles (ZnONPs) on aquatic ecosystems have attracted special attention due to their unique properties. The present investigation was designed to evaluate the possible mechanisms of ecotoxicological effects of ZnONPs on freshwater snail Biomphalaria alexandrina. ZnONPs showed molluscicidal activity against B. alexandrina snails, and the LC50 was 145 μg/ml. Two tested concentrations of ZnONPs were selected: The first concentration was equivalent to LC10 (7 μg/ml), and the second was equivalent to LC25 (35 μg/ml). Exposure to ZnONPs (7 and 35 μg/ml) for three consecutive weeks significantly induced malondialdehyde and nitric oxide with concomitant decreases in glutathione and glutathione-S-transferase levels in hemolymph and soft tissues of treated snails. Moreover, ZnONPs elicited a significant decrease in total protein and albumin contents coinciding with enhancement of total lipids and cholesterol levels as well as activities of aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase in hemolymph and soft tissues of treated snails. This study highlights the potential ecological implications of ZnONP release in aquatic environments and may serve to encourage regulatory agencies in Egypt to more carefully monitor and regulate the industrial use and disposal of ZnONPs. PMID:24736985

  13. Screening of freshwater and seawater microalgae strains in fully controlled photobioreactors for biodiesel production.

    Science.gov (United States)

    Taleb, A; Kandilian, R; Touchard, R; Montalescot, V; Rinaldi, T; Taha, S; Takache, H; Marchal, L; Legrand, J; Pruvost, J

    2016-10-01

    Strain selection is one of the primary hurdles facing cost-effective microalgal biodiesel production. Indeed, the strain used affects both upstream and downstream biodiesel production processes. This study presents a screening procedure that considers the most significant criteria in microalgal biodiesel production including TAG production and wet extraction and recovery of TAGs. Fourteen freshwater and seawater strains were investigated. Large variation was observed between the strains in all the screening criteria. The overall screening procedure ultimately led to the identification of Parachlorella kessleri UTEX2229 and Nannochloropsis gaditana CCMP527 as the best freshwater and seawater strains, respectively. They featured the largest areal TAG productivity equal to 2.7×10(-3) and 2.3×10(-3)kgm(-2)d(-1), respectively. These two strains also displayed encouraging cell fragility in a high pressure bead milling process with 69% and 98% cell disruption at 1750bar making them remarkable strains for TAG extraction in wet environment. PMID:27394994

  14. Chemical footprint method for improved communication of freshwater ecotoxicity impacts in the context of ecological limits.

    Science.gov (United States)

    Bjørn, Anders; Diamond, Miriam; Birkved, Morten; Hauschild, Michael Zwicky

    2014-11-18

    The ecological footprint method has been successful in communicating environmental impacts of anthropogenic activities in the context of ecological limits. We introduce a chemical footprint method that expresses ecotoxicity impacts from anthropogenic chemical emissions as the dilution needed to avoid freshwater ecosystem damage. The indicator is based on USEtox characterization factors with a modified toxicity reference point. Chemical footprint results can be compared to the actual dilution capacity within the geographic vicinity receiving the emissions to estimate whether its ecological limit has been exceeded and hence whether emissions can be expected to be environmentally sustainable. The footprint method was illustrated using two case studies. The first was all inventoried emissions from European countries and selected metropolitan areas in 2004, which indicated that the dilution capacity was likely exceeded for most European countries and all landlocked metropolitan areas. The second case study indicated that peak application of pesticides alone was likely to exceed Denmark's freshwater dilution capacity in 1999-2011. The uncertainty assessment showed that better spatially differentiated fate factors would be useful and pointed out other major sources of uncertainty and some opportunities to reduce these. PMID:25347848

  15. Assessing Potential Conservation and Restoration Areas of Freshwater Fish Fauna in the Indian River Basins

    Science.gov (United States)

    Bhatt, Jay P.; Manish, Kumar; Mehta, Rajender; Pandit, Maharaj K.

    2016-05-01

    Conservation efforts globally are skewed toward terrestrial ecosystems. To date, conservation of aquatic ecosystems, in particular fish fauna, is largely neglected. We provide a country-wide assessment of Indian river ecosystems in order to identify and prioritize areas for protection and restoration of freshwater fish fauna. Using various biodiversity and anthropogenic attributes, coupled with tools of ecological modeling, we delineated areas for fish fauna conservation and restoration in the 20 major river basins of India. To do this, we used prioritization analyses and reserve selection algorithms to derive conservation value index (CVI) and vulnerability index (VI) of the river basins. CVI was estimated using endemicity, rarity, conservation value, and taxonomic singularity, while VI was estimated using a disturbance index derived from percent geographic area of the basin under human settlements, human population density, predominant land use, and total number of exotic fish species in each basin. The two indices, CVI and VI, were converted into geo-referenced maps, and each map was super-imposed onto species richness and forest cover maps, respectively. After superimposition, areas with high CVI and low VI shade intensities were delineated for conservation, while areas with high CVI and high VI shade intensities were demarcated for restoration. In view of the importance of freshwater fish for human livelihoods and consumption, and ecosystems of India's rivers, we call for urgent attention to the conservation of their fish fauna along with restoration of their degraded habitats.

  16. Arctic Ocean freshwater: How robust are model simulations?

    NARCIS (Netherlands)

    Jahn, A.; Aksenov, Y.; de Cuevas, B.A.; de Steur, L.; Häkkinen, S.; Hansen, E.; Herbaut, C.; Houssais, M.N.; Karcher, M.; Kauker, F.; Lique, C.; Nguyen, A.; Pemberton, P.; Worthen, D.; Zhang, J.

    2012-01-01

    The Arctic freshwater (FW) has been the focus of many modeling studies, due to the potential impact of Arctic FW on the deep water formation in the North Atlantic. A comparison of the hindcasts from ten ocean-sea ice models shows that the simulation of the Arctic FW budget is quite different in the

  17. Three more Mangrove trees growing locally in nature in freshwater

    NARCIS (Netherlands)

    Steenis, van C.G.G.J.

    1984-01-01

    In Christmas Island (Indian Ocean) the mangrove trees Bruguiera gymnorrhiza (L.) Sav., B. sexangula (Lour.) Poir. (Rhizophoraceae) and Heritiera littoralis Ait. (Sterculiaceae) are found inland near freshwater springs at some 20-30 m altitude, far from the beach. It is concluded that the inland stan

  18. Limnology of freshwater lakes of Schirmacher Oasis, East Antarctica

    Digital Repository Service at National Institute of Oceanography (India)

    Ingole, B.S.; Parulekar, A.H.

    Ten freshwater lakes in the Schirmacher Oasis, Antarctica, with water temperature varying from 1.0 to 7.9 degrees; dissolved oxygen from 10.4 to 13.8 mg l/1 and pH from 7.6 to 8.8, were studied biologically during January-February of 1985 and 1987...

  19. Characterization of CO2 leakage into the freshwater body

    DEFF Research Database (Denmark)

    Singh, Ashok; Delfs, Jens Olaf; Shao, H.;

    2013-01-01

    urrent research into CO2 capture and storage is dominated by improving the CO2 storage capacity. In this context, risk related to CO2 leakage is an important issue which may cause environmental problems, particularly when freshwater resources nearby are intruded by the CO2 plume. In this work...

  20. The effects of fisheries management practices on freshwater ecosystems

    OpenAIRE

    COWX I. G.; GERDEAUX D.

    2004-01-01

    Metadata only record The contributions presented at the European Inland Fisheries Advisory Commission Symposium on The Effects of Fisheries Management Practises on Freshwater Ecosystems in 2002 are reviewed. The principal mechanisms of inland fisheries management concentrate on four categories: fish stock enhancement (stocking and introductions); rehabilitation and habitat manipulation for fisheries purposes, including biomanipulation; fisheries regulations; and conservation and protection...

  1. Ecological risks of pesticides in freshwater ecosystems; Part 2: insecticides

    NARCIS (Netherlands)

    Brock, T.C.M.; Wijngaarden, van R.P.A.; Geest, van G.J.

    2000-01-01

    A literature review of freshwater model ecosystem studies with insecticides was performed to assess the NOEC ecosystem for individual compounds, to compare these threshold levels with water quality standards, and to evaluate the ecological consequences of exceeding these standards. Studies were judg

  2. The relation between international trade and freshwater scarcity

    NARCIS (Netherlands)

    Hoekstra, Arjen Y.

    2010-01-01

    It is becoming increasingly important to put freshwater issues in a global context. Local water depletion and pollution are often closely tied to the structure of the global economy. With increasing trade between nations and continents, water is more frequently used to produce exported goods. Intern

  3. Vectors of invasions in freshwater invertebrates and fishes

    Science.gov (United States)

    Fuller, Pam L.; Canning-Clode, João

    2015-01-01

    Without human assistance, the terrestrial environment and oceans represent barriers to the dispersal of freshwater aquatic organisms. The ability to overcome such barriers depends on the existence of anthropogenic vectors that can transport live organisms to new areas, and the species’ biology to survive the transportation and transplantation into the new environment (Johnson et al., 2006).

  4. Differential responses of freshwater wetland soils to sulphate pollution

    NARCIS (Netherlands)

    Lamers, L.P.M.; Dolle, ten G.E.; Berg, van den S.T.G.; Delft, van S.P.J.; Roelofs, J.G.M.

    2001-01-01

    Sulphate (SO42-) reduction rates are generally low in freshwater wetlands and are regulated by the scarce availability of the ion. Increased concentrations of this electron acceptor due to sulphur (S) pollution of groundwater and surface water may, however, lead to high sulphate reduction rates now

  5. Representing Greenland ice sheet freshwater fluxes in climate models

    NARCIS (Netherlands)

    Lenaerts, Jan T M; Le Bars, Dewi; Van Kampenhout, Leo; Vizcaino, Miren; Enderlin, Ellyn M.; Van Den Broeke, Michiel R.

    2015-01-01

    Here we present a long-term (1850-2200) best estimate of Greenland ice sheet (GrIS) freshwater runoff that improves spatial detail of runoff locations and temporal resolution. Ice discharge is taken from observations since 2000 and assumed constant in time. Surface meltwater runoff is retrieved from

  6. A physically based model of global freshwater surface temperature

    NARCIS (Netherlands)

    Beek, van L.P.H.; Eikelboom, T.; Vliet, van M.T.H.; Bierkens, M.F.P.

    2012-01-01

    Temperature determines a range of physical properties of water and exerts a strong control on surface water biogeochemistry. Thus, in freshwater ecosystems the thermal regime directly affects the geographical distribution of aquatic species through their growth and metabolism and indirectly through

  7. New Records for the Freshwater Algae of Turkey

    OpenAIRE

    BAYKAL, Tülay; AKBULUT, Aydın; İlkay AÇIKGÖZ

    2009-01-01

    Algae samples were collected from important dam lakes and running waters of the Lower Euphrates Basin. Eighteen new records of Turkish freshwater algae were identified. Among these new records, 5 belong to Cyanophyta, 10 to Chlorophyta, 1 to Xanthophyta, and 2 to Bacillariophyta.

  8. High Diversity of Magnetotactic Deltaproteobacteria in a Freshwater Niche

    OpenAIRE

    Wang, Yinzhao; Lin, Wei; Li, Jinhua; Pan, Yongxin

    2013-01-01

    Knowledge of the diversity of magnetotactic bacteria in natural environments is crucial for understanding their contribution to various biological and geological processes. Here we report a high diversity of magnetotactic bacteria in a freshwater site. Ten out of 18 operational taxonomic units (OTUs) were affiliated with the Deltaproteobacteria. Some rod-shaped bacteria simultaneously synthesized greigite and magnetite magnetosomes.

  9. High diversity of magnetotactic deltaproteobacteria in a freshwater niche.

    Science.gov (United States)

    Wang, Yinzhao; Lin, Wei; Li, Jinhua; Pan, Yongxin

    2013-04-01

    Knowledge of the diversity of magnetotactic bacteria in natural environments is crucial for understanding their contribution to various biological and geological processes. Here we report a high diversity of magnetotactic bacteria in a freshwater site. Ten out of 18 operational taxonomic units (OTUs) were affiliated with the Deltaproteobacteria. Some rod-shaped bacteria simultaneously synthesized greigite and magnetite magnetosomes. PMID:23377941

  10. Human impact on freshwater ecosystem services: a global perspective.

    Science.gov (United States)

    Dodds, Walter K; Perkin, Joshuah S; Gerken, Joseph E

    2013-08-20

    Human environmental change influences freshwaters as well as the regulating, provisioning, and cultural services that ecosystems provide worldwide. Here, we assess the global human impact on the potential value of six freshwater ecosystem services (ES) and estimate the proportion of each used globally (the mean value across all countries is in parentheses): biodiversity (0.37), disturbance regulation (0.24), commodities (0.39), greenhouse gases (0.09), water availability (0.10), and water quality (0.33). We also created a composite index of the impact. Using different valuation schemes, we found that humans have used potential global freshwater ES scaled by a relative value of roughly 4-20%, with a median of 16%. All countries use a considerable amount of the potential ES value, invalidating the idea that wealthier countries have less impact on their ES once they have developed. The data suggest that humans have diminished the potential ES provided by freshwaters across the globe and that factors associated with high population growth rates are related to the overall degradation. PMID:23885808

  11. Reconnaissance investigation of water quality, bottom sediment, and biota associated with irrigation drainage in and near Stillwater Wildlife Management Area, Churchill County, Nevada, 1986-87

    Science.gov (United States)

    Hoffman, R.J.; Hallock, R.J.; Rowe, T.G.; Lico, M.S.; Burge, H.L.; Thompson, S.P.

    1990-01-01

    A reconnaissance was initiated in 1986 to determine whether the quality of irrigation-drainage water in and near the Stillwater Wildlife Management Area, Nevada, has caused or has potential to cause harmful effects on human health, fish, wildlife, or other beneficial uses of water. Samples of surface and groundwater, bottom sediment, and biota were collected from sites upstream and downstream from the Fallon agricultural area in the Carson Desert, and analyzed for potentially toxic trace elements. Other analysis included radioactive substances, major dissolved constituents, and nutrients in water, and pesticide residues in bottom sediment and biota. In areas affected by irrigation drainage, the following constituents were found to commonly exceed baseline concentrations or recommended criteria for protection of aquatic life or propagation of wildlife: In water, arsenic, boron, dissolved solids, molybdenum, sodium, and un-ionized ammonia; in bottom sediments, arsenic, lithium, mercury, molybdenum, and selenium; and in biota, arsenic, boron, chromium, copper, mercury, selenium, and zinc. In some wetlands, selenium and mercury appeared to be biomagnified, and arsenic bioaccumulated. Pesticides contamination in bottom sediments and biota was insignificant. Adverse biological effects observed during this reconnaissance included gradual vegetative changes and species loss, fish die-offs, waterfowl disease epidemics, and persistent and unexplained deaths of migratory birds. (USGS)

  12. Exceptional vertebrate biotas from the Triassic of China, and the expansion of marine ecosystems after the Permo-Triassic mass extinction

    Science.gov (United States)

    Benton, Michael J.; Zhang, Qiyue; Hu, Shixue; Chen, Zhong-Qiang; Wen, Wen; Liu, Jun; Huang, Jinyuan; Zhou, Changyong; Xie, Tao; Tong, Jinnan; Choo, Brian

    2013-10-01

    The Triassic was a time of turmoil, as life recovered from the most devastating of all mass extinctions, the Permo-Triassic event 252 million years ago. The Triassic marine rock succession of southwest China provides unique documentation of the recovery of marine life through a series of well dated, exceptionally preserved fossil assemblages in the Daye, Guanling, Zhuganpo, and Xiaowa formations. New work shows the richness of the faunas of fishes and reptiles, and that recovery of vertebrate faunas was delayed by harsh environmental conditions and then occurred rapidly in the Anisian. The key faunas of fishes and reptiles come from a limited area in eastern Yunnan and western Guizhou provinces, and these may be dated relative to shared stratigraphic units, and their palaeoenvironments reconstructed. The Luoping and Panxian biotas, both from the Guanling Formation, are dated as Anisian (Pelsonian) on the basis of conodonts and radiometric dates, the former being slightly older than the latter. The Xingyi biota is from the Zhuganpo Formation, and is Ladinian or early Carnian, while the Guanling biota is from the overlying Xiaowa Formation, dated as Carnian. The first three biotas include extensive benthos and burrowing in the sediments, and they were located in restricted basins close to shore. Further, even though the Luoping and Panxian biotas are of similar age, their faunas differ significantly, reflecting perhaps palaeogeographically isolated basins. Between the time of the Xingyi and Guanling biotas, there was a major transgression, and the Guanling biota is entirely different in character from the other three, being dominated by pelagic forms such as large floating crinoids attached to logs, very large ichthyosaurs and thalattosaurs, and pseudoplanktonic bivalves, with no benthos and no burrowing. Phylogenetic study of the fishes and marine reptiles shows apparently explosive diversification among 20 actinopterygian lineages very early in the Early Triassic

  13. Immunotoxic potential of aeration lagoon effluents for the treatment of domestic and hospital wastewaters in the freshwater mussel Elliptio complanata

    Institute of Scientific and Technical Information of China (English)

    Francois Gagné; Chantale André; Marlène Fortier; Michel Fournier

    2012-01-01

    Municipal wastewaters are major sources of pollution for the aquatic biota.The purpose of this study was to determine the levels of some pharmaceutical products and the immunotoxic potential of a municipal wastewater aeration lagoon for the treatment of the domestic wastewaters of a small town with wastewater inputs from a 400-bed hospital complex.Endemic mussels were collected,caged and placed in the final aeration lagoon and at sites 1 km upstream and 1 km downstream of the effluent outfall in the receiving river for a period of 14 days.The results showed that the final aeration lagoon contained high levels of total coliforms,conductivity and low dissolved oxygen (2.9 mg/L) as well as detectable amounts of trimethoprim,carbamazepine,gemfibrozil,and norfloxacin at concentrations exceeding 50 ng/L.The lagoon effluent was indeed toxic to the mussel specimens,as evidenced by the appearance of mortality after 14 days (10% mortality),decreased mussel weight-to-shell-length ratio and loss of hemocyte viability.The number of adhering hemocytes,phagocytic activity,total nitrite levels and arachidonic cyclooxygenase activity were significantly higher in mussels placed in the final aeration lagoon.A multivariate analysis also revealed that water pH,conductivity,total coliforms and dissolved oxygen were the endpoints most closely linked with phagocytic activity,the amount of adhering hemocytes and loss of hemocyte viability.In conclusion,exposure of mussels to treated aerated lagoon wastewater is deleterious to freshwater mussels where the immune system is compromised.

  14. Reconnaissance investigation of water quality, bottom sediment, and biota associated with irrigation drainage in the American Falls Reservoir area, Idaho, 1988-89

    Science.gov (United States)

    Low, Walton H.; Mullins, William H.

    1990-01-01

    Increased concern about the quality of irrigation drainage and its potential effects on human health, fish, and wildlife prompted the Department of the Interior to begin a program during late 1985 to identify irrigation-induced water-quality problems that might exist in the Western States. During `988, the Task Group on Irrigation Drainage selected the American Falls Reservoir area, Idaho, for study to determine whether potentially toxic concentrations of trace elements or organochlorine compounds existed in water, bottom sediment, and biota. The 91-square mile American Falls Reservoir has a total capacity of 1.7 million acre-feet and is used primarily for irrigation-water supply and power generation. Irrigated land upstream from the reservoir totals about 550,000 acres. Total water inflow to the reservoir is about 5.8 million acre-feet per year, of which about 63 percent is from surface-water runoff, 33 percent is from ground-water discharge, and about 4 percent is from ungaged tributaries, canals, ditches, sloughs, and precipitation. Ground-water discharge to the reservoir originates, in part, from irrigation of land upstream from and adjacent to the reservoir. The 1988 water year was a drought year, and water discharge was about 34 percent less than during 1939-88. Water samples were collected during the post-irrigation (October 1987) and irrigation (July 1988) seasons and were analyzed for major ions and trace elements. Bottom-sediment samples were collected during the irrigation season and were analyzed for trace elements and organochlorine compounds. Biota samples were collected during May, June, July, and August 1988 and were analyzed for trace elements and organochlorine compounds. Dissolved-solids concentrations in water ranged from 216 to 561 milligrams per liter. The similarity of dissolved-solids concentrations between the irrigation and post-irrigation seasons can be attributed to the large volume of ground-water discharge in the study area. Most trace

  15. Hydrogeology and geochemistry of the freshwater lens on Roi Namur atoll, the Republic of the Marshall Islands

    Science.gov (United States)

    Swarzenski, P. W.

    2015-12-01

    More than 90% of the world's ~400 larger atoll islands are located in the Pacific and Indian Oceans and are inhabited by ~ 3/4 million people. As ground elevations of these atolls rarely exceed a few meters above mean sea level, atoll communities must rely precariously on finite resources, including fresh water and land. When demand for water exceeds precipitation rates, fresh groundwater may provide an additional, albeit also limited resource. The shape and size of this freshwater lens is controlled by precipitation, infiltration, discharge, and groundwater pumping, as well as hydrogeologic characteristics of the aquifer, and climate. Small atoll islands like Roi Namur on Kwajalein perhaps best illustrate the strong interdependence of the islet's depositional history and geochemical transformations that occur within the shallow aquifer and its host rock. This study utilized electrical resistivity tomography (ERT) to define the position of the freshwater lens above underlying seawater and to examine scales of freshwater /saltwater mixing. Time series Rn-222 measurements were used to evaluate groundwater discharge rates to the coastal waters, and a suite of groundwater geochemical tracers, including select nutrients, trace elements, and water isotopes, were used to develop a better understanding of how the fresh water lens will likely to respond to external perturbations, such as managed recharge, and the inevitability of future marine over wash events that will be become more frequent and severe under expected sea level rise.

  16. Gulf-Wide Information System, Environmental Sensitivity Index Freshwater Fish Database, Geographic NAD83, LDWF (2001) [esi_freshwater_fish_LDWF_2001

    Data.gov (United States)

    Louisiana Geographic Information Center — This data set contains sensitive biological resource data for freshwater (inland) fish species in coastal Louisiana. Vector polygons represent water-bodies and...

  17. Comparison of the Respiratory Metabolism of Juvenile Litopenaeus vannamei Cultured in Seawater and Freshwater

    Institute of Scientific and Technical Information of China (English)

    DING Sen; WANG Fang; DONG Shuanglin; LI Ying

    2014-01-01

    Litopenaeus vannamei, a euryhaline species, can be cultured at a wide range of salinities. The emergence of freshwater pond-culture of L. vannamei is an important prelude to the continued development of shrimp culture in China. In this study, we com-pared the respiratory metabolism of juvenile L. vannamei cultured in freshwater and saltwater by measuring their oxygen consump-tion rate (OCR), ammonium-type nitrogen excretion rate (AER) and pyruvate kinase (PK) and lactate dehydrogenase (LDH) activi-ties at different molting stages in order to physiecologically characterize juvenile L. vannamei under freshwater conditions. The re-sults showed that OCR was significantly higher in saltwater than in freshwater at all stages of molting cycle. However, variation of OCR among molting stages in saltwater was similar with that in freshwater, and the highest OCR was observed at post-molting stage. At all stages of molting cycle, AER was significantly higher in freshwater than in saltwater, and the highest was observed at post-molting stage. The activity of PK was significantly higher in saltwater than in freshwater. Conversely, the activity of LDH was higher in freshwater than in saltwater in general. Significant variation of PK and LDH activities in molting cycle was observed in saltwater and freshwater. The results indicated that aerobic metabolism of juvenile L. vannamei was more active in saltwater than in freshwater;while its protein metabolism was more active in freshwater than in saltwater.

  18. Comparison of the respiratory metabolism of juvenile Litopenaeus vannamei cultured in seawater and freshwater

    Science.gov (United States)

    Ding, Sen; Wang, Fang; Dong, Shuanglin; Li, Ying

    2013-11-01

    Litopenaeus vannamei, a euryhaline species, can be cultured at a wide range of salinities. The emergence of freshwater pond-culture of L. vannamei is an important prelude to the continued development of shrimp culture in China. In this study, we compared the respiratory metabolism of juvenile L. vannamei cultured in freshwater and saltwater by measuring their oxygen consumption rate (OCR), ammonium-type nitrogen excretion rate (AER) and pyruvate kinase (PK) and lactate dehydrogenase (LDH) activities at different molting stages in order to physiecologically characterize juvenile L. vannamei under freshwater conditions. The results showed that OCR was significantly higher in saltwater than in freshwater at all stages of molting cycle. However, variation of OCR among molting stages in saltwater was similar with that in freshwater, and the highest OCR was observed at post-molting stage. At all stages of molting cycle, AER was significantly higher in freshwater than in saltwater, and the highest was observed at post-molting stage. The activity of PK was significantly higher in saltwater than in freshwater. Conversely, the activity of LDH was higher in freshwater than in saltwater in general. Significant variation of PK and LDH activities in molting cycle was observed in saltwater and freshwater. The results indicated that aerobic metabolism of juvenile L. vannamei was more active in saltwater than in freshwater; while its protein metabolism was more active in freshwater than in saltwater.

  19. Prevalence and antimicrobial resistance of Salmonella spp. in raw retail frozen imported freshwater fish to Eastern Province of Saudi Arabia

    Institute of Scientific and Technical Information of China (English)

    Nasreldin Elhadi

    2014-01-01

    Objective:To determine the proportion of imported frozen fish contaminated with Salmonella among retail food stores and supermarkets in the Eastern Province of Saudi Arabia. Methods: A total of 223 frozen freshwater fish purchased from different supermarkets and grocery stores were analyzed for the presence of foodborne pathogen Salmonella. The isolation of Salmonella was determined and confirmed by using the methods of US Food and Drug Administration’s Bacteriological Analytical Manual, CHROMagar Salmonella plus, biochemical tests and API 20E strips. Antimicrobial susceptibilities of Salmonella isolates were determined by the disk diffusion method on Muller-Hinton agar, as described by Kirby-Bauer, in accordance with the guidelines of the Clinical and Laboratory Standards Institute. Results:Out of the total 223 fish samples (20 of catfish, 18 of carfu, 20 of mirgal, 25 of milkfish, 35 of mackerel, 75 of tilapia, and 30 of rohu), 89 (39.9%) were tested positive for Salmonella. The prevalence of positive samples were reported for the freshwater fish of pangas (60.0%, n=12), carfu (27.7%, n=5), mirgal (35.0%, n=7), milkfish (52.0%, n=13), mackerel (31.4 %, n=11), tilapia imported from Thailand (64.0%, n=16), tilapia imported from India (28.0%, n=14), rohu imported from Thailand (26.6%, n=4) and rohu imported from Myanmar (46.6%, n=7). A total of 140 isolates of Salmonella spp. were yielded from at least seven different types of frozen freshwater fish imported from 5 different countries and were tested for their susceptibility to 16 selected antimicrobial agents. The highest antibiotic resistance was observed to tetracycline (90.71%) followed by ampicillin (70%) and amoxicillin-clavulanic acid (45%). Conclusions: The obtained results of this study shows that these raw retail imported frozen freshwater fish are contaminated with potentially pathogenic Salmonella spp. And the study recommend and suggest that there is a need for adequate consumer measures.

  20. Determination of methylmercury in marine biota samples with advanced mercury analyzer: method validation.

    Science.gov (United States)

    Azemard, Sabine; Vassileva, Emilia

    2015-06-01

    In this paper, we present a simple, fast and cost-effective method for determination of methyl mercury (MeHg) in marine samples. All important parameters influencing the sample preparation process were investigated and optimized. Full validation of the method was performed in accordance to the ISO-17025 (ISO/IEC, 2005) and Eurachem guidelines. Blanks, selectivity, working range (0.09-3.0ng), recovery (92-108%), intermediate precision (1.7-4.5%), traceability, limit of detection (0.009ng), limit of quantification (0.045ng) and expanded uncertainty (15%, k=2) were assessed. Estimation of the uncertainty contribution of each parameter and the demonstration of traceability of measurement results was provided as well. Furthermore, the selectivity of the method was studied by analyzing the same sample extracts by advanced mercury analyzer (AMA) and gas chromatography-atomic fluorescence spectrometry (GC-AFS). Additional validation of the proposed procedure was effectuated by participation in the IAEA-461 worldwide inter-laboratory comparison exercises. PMID:25624245