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Differential kinetics and temperature dependence of abiotic and biotic processes controlling the environmental fate of TNT in simulated marine systems Texte intégral
2011
Chappell, Mark A. | Porter, Beth E. | Price, Cynthia L. | Pettway, Brad A. | George, Robert D.
This work seeks to understand how the balance of abiotic and biotic kinetic processes in sediments control the residual concentration of TNT in marine systems after release from ocean-dumped source. Kinetics of TNT disappearance were followed using marine sediments at different temperatures and under both biotic and presumably abiotic conditions (through sodium azide addition). Sediments exhibiting the highest rate of TNT disappearance under biotic conditions also exhibited the highest sorption affinity for TNT under abiotic conditions. Significant temperature dependence in the abiotic processes was observed in the diffusion coefficient of TNT and not sediment sorption affinity. At higher temperature, kinetics of biotic processes outpaced abiotic processes, but at low temperature, kinetics of abiotic processes were much more significant. We concluded that the differential influence of temperature on the kinetics of abiotic and biotic processes could provide distinguishing predictions for the potential residual concentration of TNT contamination in marine-sediment systems.
Afficher plus [+] Moins [-]The new potential invader Linopherus canariensis (Polychaeta: Amphinomidae) in a Mediterranean coastal lake: Colonization dynamics and morphological remarks Texte intégral
2011
Cosentino, A. | Giacobbe, S.
The newly introduced polychaete Linopherus canariensis Langerhans, 1881 was found in the Lake of Faro (NE Sicily), during a study comparing the macrobenthos in artificial modules with a neighboring sandy bottom assemblage. Of a total of 4465 specimens, almost 6% showed morphological variation related to branchial turfs and mean body size. The sandy bottom exhibited an average density of 41.86indL⁻¹ and a wet biomass of 30.35mgL⁻¹, whereas the artificial substratum reached levels of 205.29indL⁻¹ and 318.44mgL⁻¹. The highest estimated immigration rate was 3.7indL⁻¹d⁻¹ (5.8mgL⁻¹d⁻¹). In the artificial microhabitat, 0.4% of the population showed mid-anterior fragmentation, with anterior- (2%), mid- (<1%) and posterior- (1%) regenerating lineages, which contributed significantly to the dispersion ability of this species. L. canariensis was a selective micro-deposit feeder, even under conditions of reduced sediments. Linopherus was found to be a new potential invader of stressed environments that is probably tied to the import of oysters.
Afficher plus [+] Moins [-]Critical appraisal on the identification of Reference Conditions for the evaluation of ecological quality status along the Emilia-Romagna coast (Italy) using M-AMBI Texte intégral
2011
Paganelli, Daniele | Forni, Giulia | Marchini, Agnese | Mazziotti, Cristina | Occhipinti, Anna
According to the European Water Framework Directive, the ecological status (ES) of a water body is determined by comparing observation data with undisturbed Reference Conditions (RCs). Defining RCs is crucial when evaluating the ES of a water body as it strongly affects the final outcome of any index application. Identifying RCs by observing real sites is not feasible in many marine environments, such as the Emilia-Romagna coast (Italy, N-Adriatic Sea). We used a statistical approach on a large dataset to derive RCs for the application of the benthic index M-AMBI in this area. We then applied M-AMBI to samples collected along a gradient of presumed environmental disturbance. The results put 14.8% of the Emilia-Romagna samples in “High” ES, 60.2% in “Good”, 23.0% in “Moderate” and 2.0% in “Poor”, showing a spatial gradient of improving quality. These results are in agreement with the extensive ecological knowledge available for this area.
Afficher plus [+] Moins [-]Integrated biomarker assessment of the effects exerted by treated produced water from an onshore natural gas processing plant in the North Sea on the mussel Mytilus edulis Texte intégral
2011
Brooks, Steven | Harman, Chris | Zaldibar, Beñat | Izagirre, Urtzi | Glette, Tormod | Marigómez, Ionan
The biological impact of a treated produced water (PW) was investigated under controlled laboratory conditions in the blue mussel, Mytilus edulis. Mussel health status was assessed using an integrated biomarker approach in combination with chemical analysis of both water (with SPMDs), and mussel tissues. Acyl-CoA oxidase activity, neutral lipid accumulation, catalase activity, micronuclei formation, lysosomal membrane stability in digestive cells and haemocytes, cell-type composition in digestive gland epithelium, and the integrity of the digestive gland tissue were measured after 5week exposure to 0%, 0.01%, 0.1%, 0.5% and 1% PW. The suite of biomarkers employed were sensitive to treated PW exposure with significant sublethal responses found at 0.01–0.5% PW, even though individual chemical compounds of PW were at extremely low concentrations in both water and mussel tissues. The study highlights the benefits of an integrated biomarker approach for determining the potential effects of exposure to complex mixtures at low concentrations. Biomarkers were integrated in the Integrative Biological Response (IBR/n) index.
Afficher plus [+] Moins [-]Fast and easy method for seagrass monitoring: Application of acoustic telemetry to precision mapping of Posidonia oceanica beds Texte intégral
2011
Descamp, Pierre | Holon, Florian | Ballesta, Laurent | Guilbert, Antonin | Guillot, Marie | Boissery, Pierre | Raimondino, Valérie | Deter, Julie
Posidonia oceanica is an endemic seagrass from the Mediterranean Sea. It is an indicator of water quality and of the ecological state of coastal ecosystems. The aim of this paper is to test acoustic telemetry for monitoring the position of P. oceanica meadow limits with varied types. After evaluating the accuracy of the system, we present results from a spatiotemporal survey of P. oceanica meadows on nine sites located on the French coast. The method has been demonstrated to be highly efficient for high precision underwater mapping regardless of meadow type, with 1cm accuracy for a distance of 40m between the base and the pointer. A temporal survey led at Cerbere–Banyuls shows a weak global progression of 4m² (progression of 26m² - regression of 22m²) between 2006 and 2010. Finally, we discuss the cost and efficiency of this method, and wether it should be generalized for further studies.
Afficher plus [+] Moins [-]Assessment of heavy metal contamination and mineral magnetic characterization of the Asopos River sediments (Central Greece) Texte intégral
2011
Botsou, F. | Karageorgis, A.P. | Dassenakis, E. | Scoullos, M.
The content and distribution of heavy metals in sediments of the intermittent and contaminated Asopos River, located in Central Greece, was assessed by means of total dissolution, dilute acid and sequential extraction procedures. Mineral magnetic properties were used as proxy parameters of transport mechanisms of land-derived material to the sea. The combination of enrichment factors estimated against local background levels and the levels of labile metals revealed that surface sediments are enriched in Cu, Cd, Ni and Cr. The low flow of the system allows particles and organic matter to accumulate in the estuarine shallow “pools” where they undertake a series of redox reactions, authigenic formation, etc. The most fine of these particles, which are metal rich, are transported to relatively long distances off the Asopos River mouth, even under low energy conditions, converting the system to a secondary source of pollution for the adjacent marine environment.
Afficher plus [+] Moins [-]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 Texte intégral
2011
Haberkorn, Hansy | Tran, Damien | Massabuau, Jean-Charles | Ciret, Pierre | Savar, Véronique | Soudant, Philippe
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 Texte intégral
2011
Haberkorn, Hansy | Tran, Damien | Massabuau, Jean-Charles | Ciret, Pierre | Savar, Véronique | Soudant, Philippe
The complexity of the relationships between Alexandrium minutum (A.m.) 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 10×10³cellsml⁻¹ (experiment-1) and 5×10³cellsml⁻¹ (experiment-2): 100% A.m.; 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 10×10³cellsml⁻¹, the microalgal ingestion decreased (p<0.05) with increasing [A.m.]w but not at 5×10³cellsml⁻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.
Afficher plus [+] Moins [-]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 Texte intégral
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.
Afficher plus [+] Moins [-]PCBs in Central Vietnam coastal lagoons: Levels and trends in dynamic environments Texte intégral
2011
Giuliani, Silvia | Piazza, Rossano | Bellucci, Luca Giorgio | Cu, Nguyen Huu | Vecchiato, Marco | Romano, Stefania | Mugnai, Cristian | Nhon, Dang Hoai | Frignani, Mauro
PCBs were analysed in surficial sediments and selected sediment cores collected between 2002 and 2008 in Central Vietnam coastal lagoons. The aim was to determine contamination levels and trends, and to evaluate the effects of anthropogenic pressures and natural events. Samples were mostly fine-grained with low total PCB concentrations (0.367–44.7μgkg⁻¹). Atmospheric transport and post depositional processes modify to some degree the fingerprint of PCB inputs to the environment favouring the predominance of 3, 4 and 5 chlorinated congeners. The similarity of congener distributions in contemporary surficial samples also suggests the presence of a unique source over the entire study area, probably connected to mobilisation and long range transports from land-based stocks. The removal of consistent sediment layers is hypothesised based on repeated samplings of the same area. Natural meteorological events (such as typhoons) are suspected to be responsible for these sediment losses.
Afficher plus [+] Moins [-]Carbon and nitrogen cycling in the Zhubi coral reef lagoon of the South China Sea as revealed by ²¹⁰Po and ²¹⁰Pb Texte intégral
2011
Yang, W.F. | Huang, Y.P. | Chen, M. | Qiu, Y.S. | Li, H.B. | Zhang, L.
The radionuclides ²¹⁰Po and ²¹⁰Pb were examined to trace the cycling of particulate organic carbon (POC) and particulate organic nitrogen (PON) in the Zhubi coral reef lagoon. The net export flux of POC to the open sea is 14mgCm⁻²d⁻¹. However, the net exchange of PON has not yet been observed. On average, the vertical export fluxes in the lagoon of POC and PON, as derived from ²¹⁰Po/²¹⁰Pb disequilibria, are 43mgCm⁻²d⁻¹ and 13.8mgNm⁻²d⁻¹, respectively. The deficit of ²¹⁰Po relative to ²¹⁰Pb in particulate matter provides evidence for the degradation of particulate organic matter. According to the mass balance budgets, 310mgCm⁻²d⁻¹ and 121mgNm⁻²d⁻¹ were recycled into dissolved fractions. Based on a first-order kinetics model, the degradation rate constants of POC and PON are 0.28 and 0.30m⁻¹, respectively. Thus, ²¹⁰Po and ²¹⁰Pb can quantify the cycling of carbon and nitrogen in this coral lagoon.
Afficher plus [+] Moins [-]Profiles of nonylphenol isomers in surface waters from Sri Lanka Texte intégral
2011
Guruge, Keerthi S. | Horii, Yuichi | Yamashita, Nobuyoshi
Isomer-specific concentrations of nonylphenol (NP) and their predicted estrogenic potency were investigated in Sri Lankan waters for the first time. The total concentration of 13 NP isomers ranged from 90 to 1835ng/L, while the predicted estrogenic equivalent concentration ranged from 0.072 to 1.38ng 17β-estradiol (E2)/L. Bire Lake, located in the central area of the commercial capital, Colombo, had the highest contamination among the studied locations. These data show that NP levels in Sri Lankan waters are well within the recently reported concentrations in other regions of the world. The spatial differences in NP concentrations suggest that NP contamination in Sri Lanka may be widespread, and comprehensive study is vital.
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