خيارات البحث
النتائج 451 - 460 من 1,273
Polychlorinated biphenyls in freshwater salmonids from the Kerguelen Islands in the Southern Ocean
2011
Jaffal, A. | Givaudan, N. | Betoulle, S. | Terreau, A. | Paris-Palacios, S. | Biagianti-Risbourg, S. | Beall, E. | Roche, H.
The Subantarctic Kerguelen Islands (49°S, 70°E) 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 358ngg⁻¹ lipid, and dioxin-like PCB was 19 and 69ngg⁻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.
اظهر المزيد [+] اقل [-]Carbon isotope composition, macronutrient concentrations, and carboxylating enzymes in relation to the growth of <em>Pinus halepensis</em> mill. when subject to ozone stress
2011
Inclan, Rosa | Gimeno, Benjamin S. | Penuelas, Josep | Gerant, Dominique | Querido, Alberto | Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT) | Universitat Autònoma de Barcelona (UAB) | Ecologie et Ecophysiologie Forestières [devient SILVA en 2018] (EEF) ; Institut National de la Recherche Agronomique (INRA)-Université de Lorraine (UL)
International audience | We present here the effects of ambient ozone (O3)-induced decline in carbon availability, accelerated foliar senescence, and a decrease in aboveground biomass accumulation in the Aleppo pine (Pinus halepensis Mill.). Aleppo pine seedlings were continuously exposed in open-top chambers for 39 months to three different types of O3 treatments, which are as follows: charcoal-filtered air, nonfiltered air (NFA), and nonfiltered air supplemented with 40 ppb O3 (NFA+). Stable carbon isotope discrimination (Δ) and derived time-integrated ci/ca ratios were reduced after an accumulated ozone exposure over a threshold of 40 ppb (AOT40) value from April to September of around 20,000 ppb·h. An AOT40 of above 67,000 ppb·h induced reductions in ribulose-1, 5-biphosphate carboxylase/oxygenase activity, aboveground C and needle N and K concentrations, the C/N ratio, Ca concentrations in twigs under 3 mm, and the aerial biomass, as well as increases in needle P concentrations and phosphoenolpyruvate carboxylase (PEPC) activity and the N and K concentrations in twigs under 3 mm. Macronutrients losses, the limitations placed on carbon uptake, and increases in catabolic processes may be the causes of carbon gain diminution in leaves which was reflected as a reduction in aboveground biomass at tree level. Stimulation of PEPC activity, the consequent decreased Δ, and compensation processes in nutrient distribution may increase O3 tolerance and might be interpreted as part of Aleppo pine acclimation response to O3.
اظهر المزيد [+] اقل [-]Atmospheric concentrations, occurrence and deposition of persistent organic pollutants (POPs) in a Mediterranean coastal site (Etang de Thau, France)
2011
Castro Jimenez, Javier | Mariani, G. | Vives, I. | Skejo, H. | Umlauf, G. | Zaldivar, J. M. | Dueri, Sibylle | Messiaen, Gregory | Laugier, Thierry
Atmospheric concentrations and deposition fluxes of PCDD/F and PCB have been evaluated over a 1-year period in a Mediterranean coastal lagoon (Etang de Thau, France). Indicative PBDE air concentrations in the hot season are also reported in this work. ∑2,3,7,8-PCDD/Fs and ∑18PCBs (gas + particulate) air concentrations ranged from 67 to 1700 fg m−3 and from 13 to 95 pg m−3, respectively whereas ∑8PBDEs (gas + particulate) summer time levels varied from 158 to 230 pg m−3. The PCDD/F and PCB atmospheric occurrence over Thau lagoon and subsequent inputs to the surface waters are determined by an assemble of factors, being the seasonality of atmospheric concentration, the air mass origin and meteorological conditions important drivers. Total (wet + dry) ∑2,3,7,8-PCDD/Fs and ∑18PCBs deposition fluxes to Thau Lagoon waters are 117 and 715 pg m−2 d−1, respectively.
اظهر المزيد [+] اقل [-]Bioavailability of particulate metal to zebra mussels: Biodynamic modelling shows that assimilation efficiencies are site-specific
2011
Bourgeault, Adeline | Gourlay-france, Catherine | Priadi, Cindy | Ayrault, Sophie | Tusseau-vuillemin, Marie-helene
This study investigates the ability of the biodynamic model to predict the trophic bioaccumulation of cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni) and zinc (Zn) in a freshwater bivalve. Zebra mussels were transplanted to three sites along the Seine River (France) and collected monthly for 11 months. Measurements of the metal body burdens in mussels were compared with the predictions from the biodynamic model. The exchangeable fraction of metal particles did not account for the bioavailability of particulate metals, since it did not capture the differences between sites. The assimilation efficiency (AE) parameter is necessary to take into account biotic factors influencing particulate metal bioavailability. The biodynamic model, applied with AEs from the literature, overestimated the measured concentrations in zebra mussels, the extent of overestimation being site-specific. Therefore, an original methodology was proposed for in situ AE measurements for each site and metal. (C) 2011 Elsevier Ltd. All rights reserved.
اظهر المزيد [+] اقل [-]Impact of atmospheric deposition of anthropogenic and natural trace metals on Northwestern Mediterranean surface waters: A box model assessment
2011
Heimbuerger, Lars-eric | Migon, Christophe | Cossa, Daniel
Under stratified oligotrophic conditions (May November), the surface mixed layer of the Northwestern Mediterranean constitutes a homogeneous water volume of 10-30 m depth. In other respects, the mean residence time of Ligurian surface waters (0-200 m) is 102 days. It is therefore possible to quantify the extent to which atmospheric deposition of trace metals affects surface waters. On the basis of literature data on anthropogenic and natural trace metals, we demonstrate that the ratios between total seawater labile atmospheric deposition during 102 days (Delta c) and dissolved TM concentrations in Ligurian surface waters (c) illustrate the impact of atmospheric deposition on surface seawater (Delta c/c). High ratios indicate surface TM enrichments, while low ratios indicate surface TM depletion, due to the quasi-complete sorption and removal of TMs by plankton during spring bloom. The simple box model proposed here may be used for other marine regions where hydrodynamical and physico-chemical constraints are well defined. (C) 2011 Elsevier Ltd. All rights reserved.
اظهر المزيد [+] اقل [-]Recommendations on methods for the detection and control of biological pollution in marine coastal waters
2011
Olenin, Sergej | Elliott, Michael | Bysveen, Ingrid | Culverhouse, Phil F. | Daunys, Darius | Dubelaar, George B. J. | Gollasch, Stephan | Goulletquer, Philippe | Jelmert, Anders | Kantor, Yuri | Mezeth, Kjersti Bringsvor | Minchin, Dan | Occhipinti-ambrogi, Anna | Olenina, Irina | Vandekerkhove, Jochen
Adverse effects of invasive alien species (IAS), or biological pollution, is an increasing problem in marine coastal waters, which remains high on the environmental management agenda. All maritime countries need to assess the size of this problem and consider effective mechanisms to prevent introductions, and if necessary and where possible to monitor, contain, control or eradicate the introduced impacting organisms. Despite this, and in contrast to more enclosed water bodies, the openness of marine systems indicates that once species are in an area then eradication is usually impossible. Most institutions in countries are aware of the problem and have sufficient governance in place for management. However, there is still a general lack of commitment and concerted action plans are needed to address this problem. This paper provides recommendations resulting from an international workshop based upon a large amount of experience relating to the assessment and control of biopollution. Highlights ► We summarize the results of an international workshop on marine biopollution. ► We recommend science-based information support for bioinvasion management. ► We outline types of bioinvasion monitoring and consider topical research needs. ► We emphasize the role of taxonomy training and public involvement. ► Biopollution should be treated in the same way as any other type of pollution.
اظهر المزيد [+] اقل [-]Relationship between valve activity, microalgae concentration in the water and toxin accumulation in the digestive gland of the Pacific oyster Crassostrea gigas exposed to Alexandrium minutum
2011
Haberkorn, Hansy | Tran, Damien | Massabuau, Jean-charles | Ciret, Pierre | Savar, Veronique | Soudant, Philippe
The complexity of the relationships between Alexandrium minutum (Am.) concentration in the water ([A.m.](w)), Paralytic Shellfish Poisoning contamination in the digestive gland ([PSP](dg)) and valve behavior was explored in oysters Crassostrea gigas. Two experiments were conducted, during which oysters' valve behaviour were analyzed. Oysters, first acclimated for 10-days with the non harmful microalgae Heterocapsa triquetra (H.t.), were exposed to four microalgae mixtures at constant total concentrations of 10 x 10(3) cells ml(-1) (experiment-1) and 5 x 10(3) cells ml(-1) (experiment-2): 100% Am.; 50% A.m.-50% H.t.; 25% A.m.-75% H.t.; 100% H.t. At the end of experiment-2, [PSP](dg) were measured. At 10 x 103 cells ml(-1), the microalgal ingestion decreased (p < 0.05) with increasing [A.m.](w) but not at 5 x 10(3) cells ml(-1) (p > 0.05). The frequency of microclosures specifically increased with [A.m.](w) (p < 0.05) and the opening duration with [PSP](dg) (p < 0.0001). Oysters exhibiting the maximum increase in opening duration also exhibited the highest [PSP](dg). The results are discussed in terms of oyster physiology and origin of the behavioral response. (C) 2011 Elsevier Ltd. All rights reserved.
اظهر المزيد [+] اقل [-]Analysis of bacterial diversity and metals in produced water, seawater and sediments from an offshore oil and gas production platform
2011
Yeung, C William | Law, Brent A. | Milligan, Tim G. | Lee, Kenneth | Whyte, Lyle G. | Greer, Charles W.
Produced water is one of the largest waste products routinely discharged into the ocean from offshore oil and gas platforms. This study analyzed bacterial communities and metals in the produced water, surrounding seawater, and sediment around the Thebaud platform. The bacterial community within the produced water was different from the seawater (SAB=13.3), but the discharge had no detectable effect on the bacterial communities in the seawater (SAB>97). In contrast, genomic analysis of sediments revealed that the bacterial community from 250m was different (SAB=70) from other locations further from the discharge, suggesting that the produced water had a detectable effect on the bacterial community in the sediment closest to the discharge. These near-field sediments contained elevated concentrations of manganese and iron that are associated with the produced water effluent. The results suggested that the discharge of produced water has influenced the bacterial community structure of sediments adjacent to the platform.
اظهر المزيد [+] اقل [-]Mercury in blood and eggs of the sea turtle Lepidochelys olivacea from a nesting colony in Oaxaca, Mexico
2011
Páez-Osuna, F. | Calderón-Campuzano, M.F. | Soto-Jiménez, M.F. | Ruelas-Inzunza, J.
Mercury concentrations were assessed in the sea turtle Lepidochelys olivacea from a nesting colony of Oaxaca, Mexico; 25 female turtles were sampled, a total of 250 eggs were collected during the season 2005–2006. Higher concentrations were found in yolk fraction, while in blood and albumen mean levels were below of 0.0010μgg⁻¹ dry wt. On the basis of one nesting season, the maternal transfer of Hg via eggs-laying was estimated in 2.0±1.1%. According to international norms, the health of this population and its habitats is acceptable for Hg and corresponds to baseline levels of a nearly pristine environment.
اظهر المزيد [+] اقل [-]Levels and distribution of polybrominated diphenyl ethers and organochlorine compounds in sea turtles from Japan
2011
Malarvannan, Govindan | Takahashi, Shin | Isobe, Tomohiko | Kunisue, Tatsuya | Sudaryanto, Agus | Miyagi, Toshihiko | Nakamura, Masaru | Yasumura, Shigeki | Tanabe, Shinsuke
Three species of sea turtles (green, hawksbill and loggerhead turtles) stranded along the coasts or caught (by-catch) around Ishigaki Island and Kochi, Japan were collected between 1998 and 2006 and analyzed for six organohalogen compounds viz., PBDEs, PCBs, DDTs, CHLs, HCHs and HCB. The present study is the first and foremost to report the occurrence of organohalogen compounds in the sea turtles from Japan. Among the compounds analyzed, concentrations of PCBs, DDTs and CHLs were the highest in all the turtle samples. PBDEs were ubiquitously present in all the turtle species. Comparing with the other two species, concentrations of organohalogens in green turtle were relatively low and decreasing trend in the concentrations were noted with increasing carapace length. Concentrations of OCs in sea turtles from the coasts of Ishigaki Island and Kochi were relatively low as compared to those from other locations in the world.
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