The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
Pierre-guy Sauriau - One of the best experts on this subject based on the ideXlab platform.
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Influence of the mode of macrofauna-mediated bioturbation on the vertical distribution of living benthic foraminifera : first insight from axial tomodensitometry
Journal of Experimental Marine Biology and Ecology, 2009Co-Authors: Vincent M.p. Bouchet, Pierre-guy Sauriau, Jean-claude Amiard, Jean-pierre Debenay, Florian Mermillod-blondin, Sabine Schmidt, Benoît DupasAbstract:We investigated the influence of bioturbation by macrofauna on the vertical distribution of living (stained) benthic foraminifera in marine intertidal sediments. We investigated the links between macrofaunal bioturbation and foraminiferal distribution, by sampling from stations situated on a gradient of perturbation by Oyster-Farming, which has a major effect on benthic faunal assemblages. Sediment cores were collected on the French Atlantic coast, from three intertidal stations: an Oyster farm, an area without Oysters but affected by Oyster biodeposits, and a control station. Axial tomodensitometry (CT-scan) was used for threedimensional visualization and two-dimensional analysis of the cores. Biogenic structure volumes were quantified and compared between cores. We collected the macrofauna, living foraminifera, shells and gravel from the cores after scanning, to validate image analysis. We did not investigate differences in the biogenic structure volume between cores. However, biogenic structure volume is not necessarily proportional to the extent of bioturbation in a core, given that many biodiffusive activities cannot be detected on CT-scans. Biodiffusors and larger gallery-diffusors were abundant in macrofaunal assemblage at the control station. By contrast, macrofaunal assemblages consisted principally of downward-conveyors at the two stations affected by Oyster Farming. At the control station, the vertical distribution of biogenic structures mainly built by the biodiffusor Scorbicularia plana and the large gallery-diffusor Hediste diversicolor was significantly correlated with the vertical profiles of living foraminifera in the sediment, whereas vertical distributions of foraminifera and downward-conveyors were not correlated at the station affected by Oyster Farming. This relationship was probably responsible for the collection of foraminifera in deep sediment layers (N6 cm below the sediment surface) at the control station. As previously suggested for other species, oxygen diffusion may occur via the burrows built by S. plana and H. diversicolor, potentially increasing oxygen penetration and providing a favorable microhabitat for foraminifera in terms of oxygen levels. By contrast, the absence of living foraminifera below 6 cm at the stations affected by Oyster Farming was probably associated with a lack of biodiffusor and large gallery-diffusor bioturbation. Our findings suggest that the effect of macrofaunal bioturbation on the vertical distribution of foraminiferal assemblages in sediments depends on the effects of the macrofauna on bioirrigation and sediment oxidation, as deduced by Eh values, rather than on the biogenic structure volume produced by macrofauna. The loss of bioturbator functional diversity due to Oyster Farming may thus indirectly affect infaunal communities by suppressing favorable microhabitats produced by bioturbation.
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Influence of the mode of macrofauna-mediated bioturbation on the vertical distribution of living benthic foraminifera : first insight from axial tomodensitometry
Journal of Experimental Marine Biology and Ecology, 2009Co-Authors: Vincent M.p. Bouchet, Pierre-guy Sauriau, Jean-claude Amiard, Jean-pierre Debenay, Florian Mermillod-blondin, Sabine Schmidt, Benoît DupasAbstract:We investigated the influence of bioturbation by macrofauna on the vertical distribution of living (stained) benthic foraminifera in marine intertidal sediments. We investigated the links between macrofaunal bioturbation and foraminiferal distribution, by sampling from stations situated on a gradient of perturbation by Oyster-Farming, which has a major effect on benthic faunal assemblages. Sediment cores were collected on the French Atlantic coast, from three intertidal stations: an Oyster farm, an area without Oysters but affected by Oyster biodeposits, and a control station. Axial tomodensitometry (CT-scan) was used for threedimensional visualization and two-dimensional analysis of the cores. Biogenic structure volumes were quantified and compared between cores. We collected the macrofauna, living foraminifera, shells and gravel from the cores after scanning, to validate image analysis. We did not investigate differences in the biogenic structure volume between cores. However, biogenic structure volume is not necessarily proportional to the extent of bioturbation in a core, given that many biodiffusive activities cannot be detected on CT-scans. Biodiffusors and larger gallery-diffusors were abundant in macrofaunal assemblage at the control station. By contrast, macrofaunal assemblages consisted principally of downward-conveyors at the two stations affected by Oyster Farming. At the control station, the vertical distribution of biogenic structures mainly built by the biodiffusor Scorbicularia plana and the large gallery-diffusor Hediste diversicolor was significantly correlated with the vertical profiles of living foraminifera in the sediment, whereas vertical distributions of foraminifera and downward-conveyors were not correlated at the station affected by Oyster Farming. This relationship was probably responsible for the collection of foraminifera in deep sediment layers (N6 cm below the sediment surface) at the control station. As previously suggested for other species, oxygen diffusion may occur via the burrows built by S. plana and H. diversicolor, potentially increasing oxygen penetration and providing a favorable microhabitat for foraminifera in terms of oxygen levels. By contrast, the absence of living foraminifera below 6 cm at the stations affected by Oyster Farming was probably associated with a lack of biodiffusor and large gallery-diffusor bioturbation. Our findings suggest that the effect of macrofaunal bioturbation on the vertical distribution of foraminiferal assemblages in sediments depends on the effects of the macrofauna on bioirrigation and sediment oxidation, as deduced by Eh values, rather than on the biogenic structure volume produced by macrofauna. The loss of bioturbator functional diversity due to Oyster Farming may thus indirectly affect infaunal communities by suppressing favorable microhabitats produced by bioturbation.
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influence of Oyster culture practices and environmental conditions on the ecological status of intertidal mudflats in the pertuis charentais sw france a multi index approach
Marine Pollution Bulletin, 2008Co-Authors: Pierre-guy Sauriau, Vincent M.p. BouchetAbstract:The ecological quality status (EcoQ) of intertidal mudflats constrained by Pacific Oyster Farming was assessed by single (H', AMBI, BENTIX and BOPA) and multimetric (M-AMBI and average score) index approaches in the Pertuis Charentais (SW France). Fifteen sampling stations were monitored seasonally for sedimentological features and macrozoobenthos in 2004. Sediments affected by Oyster biodeposits showed organic matter enrichment, and sediments from off-bottom culture sites had higher organic matter contents and lower redox potentials than sediments from on-bottom culture sites. Biotic indices consistently registered responses of macrozoobenthos to organic enrichment but there was only partial agreement between single index-derived EcoQs. The average score was better than M-AMBI and single indices for determining EcoQs. Accordingly, Oyster Farming alters intertidal macrozoobenthic assemblages moderately, and off-bottom cultures cause more disturbance than on-bottom cultures. Hydrodynamics and seasons may interact with culture practices in smothering/strengthening biodeposition-mediated effects through dispersal/accumulation of biodeposits.
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Dynamics and sources of suspended particulate organic matter in the Marennes-Oléron Oyster Farming bay: Insights from stable isotopes and microalgae ecology
Estuarine Coastal and Shelf Science, 2008Co-Authors: Nathalie Malet, Pierre-guy Sauriau, Mireille Ryckaert, Pascale Malestroit, Gaël GuillouAbstract:The aim of this study was to distinguish between sources of the complex variety of Marennes-Oléron Bay suspended particulate organic matter (SPOM) contributing to the tropho-dynamics of the Marennes-Oléron Oyster Farming bay. Basic biomarkers (Chl a, C/N and POC/Chl a ratios), carbon and nitrogen stable isotopes from SPOM were analyzed and the microalgae community was characterized. The sampling strategy was bimonthly from March 2002 to December 2003; samples were taken from an intertidal mudflat. Four main sources contributed to the SPOM pool: terrigenous input from rivers, neritic phytoplankton, resuspended microphytobenthos and periodic inputs from intertidal Zostera noltii meadows. Seasonal fluctuations were observed in both years of the study period: (1) SPOM collected in the spring of 2002 (δ13C = −25‰ to −23‰) was mainly composed of fresh estuarine inputs; (2) SPOM from the summer and fall of 2002 and 2003 was predominantly neritic phytoplankton (δ13C = − 22‰ to −19‰); (3) SPOM from the winter of 2002, spring of 2003 and winter of 2003 (δ13C = −21 to −23‰) was composed of a mixture of decayed terrigenous river inputs and pelagic phytoplankton, which was predominantly resuspended microphytobenthos. In the summer of 2003—the warmest summer on record in southern France and Europe—SPOM was particularly enriched for 13C, with δ13C values ranging from −14‰ to −12‰. Pulses in δ13C values, indicative of 13C-enriched decaying materials, extended into the fall. These were attributed to benthic intertidal inputs, including both resuspended microphytobenthos and Z. noltii detritus. Changes in SPOM sources in Marennes-Oléron Bay may lead to differences in the quality of the trophic environment available for reared Oysters.
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Dynamics and sources of suspended particulate organic matter in the Marennes-Oléron Oyster Farming bay: Insights from stable isotopes and microalgae ecology
Estuarine Coastal and Shelf Science, 2008Co-Authors: Nathalie Malet, Pierre-guy Sauriau, Mireille Ryckaert, Pascale Malestroit, Gaël GuillouAbstract:Abstract The aim of this study was to distinguish between sources of the complex variety of Marennes-Oleron Bay suspended particulate organic matter (SPOM) contributing to the tropho-dynamics of the Marennes-Oleron Oyster Farming bay. Basic biomarkers (Chl a , C/N and POC/Chl a ratios), carbon and nitrogen stable isotopes from SPOM were analyzed and the microalgae community was characterized. The sampling strategy was bimonthly from March 2002 to December 2003; samples were taken from an intertidal mudflat. Four main sources contributed to the SPOM pool: terrigenous input from rivers, neritic phytoplankton, resuspended microphytobenthos and periodic inputs from intertidal Zostera noltii meadows. Seasonal fluctuations were observed in both years of the study period: (1) SPOM collected in the spring of 2002 (δ 13 C = −25‰ to −23‰) was mainly composed of fresh estuarine inputs; (2) SPOM from the summer and fall of 2002 and 2003 was predominantly neritic phytoplankton (δ 13 C = − 22‰ to −19‰); (3) SPOM from the winter of 2002, spring of 2003 and winter of 2003 (δ 13 C = −21 to −23‰) was composed of a mixture of decayed terrigenous river inputs and pelagic phytoplankton, which was predominantly resuspended microphytobenthos. In the summer of 2003—the warmest summer on record in southern France and Europe—SPOM was particularly enriched for 13 C, with δ 13 C values ranging from −14‰ to −12‰. Pulses in δ 13 C values, indicative of 13 C-enriched decaying materials, extended into the fall. These were attributed to benthic intertidal inputs, including both resuspended microphytobenthos and Z. noltii detritus. Changes in SPOM sources in Marennes-Oleron Bay may lead to differences in the quality of the trophic environment available for reared Oysters.
David Doxaran - One of the best experts on this subject based on the ideXlab platform.
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Remote sensing of suspended particulate matter in turbid Oyster‐Farming ecosystems
Journal of Geophysical Research: Oceans, 2014Co-Authors: Pierre Gernez, Laurent Barillé, Astrid Lerouxel, Constant Mazeran, Axel Lucas, David DoxaranAbstract:High resolution satellite data of the Medium Resolution Imaging Spectrometer in full resolution mode (MERIS FR, pixel size is 300 m) were used to study the impact of suspended particulate matter (SPM) on Oyster-Farming sites in a macrotidal bay of the French Atlantic coast where SPM concentration can exceed 100 g m−3. Because MERIS standard SPM concentration retrieval saturates at about 50 g m−3, we developed an alternative method for turbid nearshore waters. The method consists in the combination of the Semi-Analytical Atmospheric and Bio-Optical (SAABIO) atmospheric correction with a regional bio-optical algorithm based on a linear relationship between SPM concentration and the reflectance band ratio at 865 and 560 nm. MERIS FR-derived SPM concentrations were validated from 10 up to 300 g m−3, and then merged with Oyster ecophysiological responses to provide a spatial picture of the impact of SPM concentration on Oyster-Farming sites. Our approach demonstrates the potential of high resolution satellite remote sensing for aquaculture management and shellfish-Farming ecosystems studies.
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remote sensing of suspended particulate matter in turbid Oyster Farming ecosystems
Journal of Geophysical Research, 2014Co-Authors: Pierre Gernez, Laurent Barillé, Astrid Lerouxel, Constant Mazeran, Axel Lucas, David DoxaranAbstract:High resolution satellite data of the Medium Resolution Imaging Spectrometer in full resolution mode (MERIS FR, pixel size is 300 m) were used to study the impact of suspended particulate matter (SPM) on Oyster-Farming sites in a macrotidal bay of the French Atlantic coast where SPM concentration can exceed 100 g m−3. Because MERIS standard SPM concentration retrieval saturates at about 50 g m−3, we developed an alternative method for turbid nearshore waters. The method consists in the combination of the Semi-Analytical Atmospheric and Bio-Optical (SAABIO) atmospheric correction with a regional bio-optical algorithm based on a linear relationship between SPM concentration and the reflectance band ratio at 865 and 560 nm. MERIS FR-derived SPM concentrations were validated from 10 up to 300 g m−3, and then merged with Oyster ecophysiological responses to provide a spatial picture of the impact of SPM concentration on Oyster-Farming sites. Our approach demonstrates the potential of high resolution satellite remote sensing for aquaculture management and shellfish-Farming ecosystems studies.
Pierre Gernez - One of the best experts on this subject based on the ideXlab platform.
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Remote sensing of suspended particulate matter in turbid Oyster‐Farming ecosystems
Journal of Geophysical Research: Oceans, 2014Co-Authors: Pierre Gernez, Laurent Barillé, Astrid Lerouxel, Constant Mazeran, Axel Lucas, David DoxaranAbstract:High resolution satellite data of the Medium Resolution Imaging Spectrometer in full resolution mode (MERIS FR, pixel size is 300 m) were used to study the impact of suspended particulate matter (SPM) on Oyster-Farming sites in a macrotidal bay of the French Atlantic coast where SPM concentration can exceed 100 g m−3. Because MERIS standard SPM concentration retrieval saturates at about 50 g m−3, we developed an alternative method for turbid nearshore waters. The method consists in the combination of the Semi-Analytical Atmospheric and Bio-Optical (SAABIO) atmospheric correction with a regional bio-optical algorithm based on a linear relationship between SPM concentration and the reflectance band ratio at 865 and 560 nm. MERIS FR-derived SPM concentrations were validated from 10 up to 300 g m−3, and then merged with Oyster ecophysiological responses to provide a spatial picture of the impact of SPM concentration on Oyster-Farming sites. Our approach demonstrates the potential of high resolution satellite remote sensing for aquaculture management and shellfish-Farming ecosystems studies.
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remote sensing of suspended particulate matter in turbid Oyster Farming ecosystems
Journal of Geophysical Research, 2014Co-Authors: Pierre Gernez, Laurent Barillé, Astrid Lerouxel, Constant Mazeran, Axel Lucas, David DoxaranAbstract:High resolution satellite data of the Medium Resolution Imaging Spectrometer in full resolution mode (MERIS FR, pixel size is 300 m) were used to study the impact of suspended particulate matter (SPM) on Oyster-Farming sites in a macrotidal bay of the French Atlantic coast where SPM concentration can exceed 100 g m−3. Because MERIS standard SPM concentration retrieval saturates at about 50 g m−3, we developed an alternative method for turbid nearshore waters. The method consists in the combination of the Semi-Analytical Atmospheric and Bio-Optical (SAABIO) atmospheric correction with a regional bio-optical algorithm based on a linear relationship between SPM concentration and the reflectance band ratio at 865 and 560 nm. MERIS FR-derived SPM concentrations were validated from 10 up to 300 g m−3, and then merged with Oyster ecophysiological responses to provide a spatial picture of the impact of SPM concentration on Oyster-Farming sites. Our approach demonstrates the potential of high resolution satellite remote sensing for aquaculture management and shellfish-Farming ecosystems studies.
Gaël Guillou - One of the best experts on this subject based on the ideXlab platform.
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Dynamics and sources of suspended particulate organic matter in the Marennes-Oléron Oyster Farming bay: Insights from stable isotopes and microalgae ecology
Estuarine Coastal and Shelf Science, 2008Co-Authors: Nathalie Malet, Pierre-guy Sauriau, Mireille Ryckaert, Pascale Malestroit, Gaël GuillouAbstract:The aim of this study was to distinguish between sources of the complex variety of Marennes-Oléron Bay suspended particulate organic matter (SPOM) contributing to the tropho-dynamics of the Marennes-Oléron Oyster Farming bay. Basic biomarkers (Chl a, C/N and POC/Chl a ratios), carbon and nitrogen stable isotopes from SPOM were analyzed and the microalgae community was characterized. The sampling strategy was bimonthly from March 2002 to December 2003; samples were taken from an intertidal mudflat. Four main sources contributed to the SPOM pool: terrigenous input from rivers, neritic phytoplankton, resuspended microphytobenthos and periodic inputs from intertidal Zostera noltii meadows. Seasonal fluctuations were observed in both years of the study period: (1) SPOM collected in the spring of 2002 (δ13C = −25‰ to −23‰) was mainly composed of fresh estuarine inputs; (2) SPOM from the summer and fall of 2002 and 2003 was predominantly neritic phytoplankton (δ13C = − 22‰ to −19‰); (3) SPOM from the winter of 2002, spring of 2003 and winter of 2003 (δ13C = −21 to −23‰) was composed of a mixture of decayed terrigenous river inputs and pelagic phytoplankton, which was predominantly resuspended microphytobenthos. In the summer of 2003—the warmest summer on record in southern France and Europe—SPOM was particularly enriched for 13C, with δ13C values ranging from −14‰ to −12‰. Pulses in δ13C values, indicative of 13C-enriched decaying materials, extended into the fall. These were attributed to benthic intertidal inputs, including both resuspended microphytobenthos and Z. noltii detritus. Changes in SPOM sources in Marennes-Oléron Bay may lead to differences in the quality of the trophic environment available for reared Oysters.
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Dynamics and sources of suspended particulate organic matter in the Marennes-Oléron Oyster Farming bay: Insights from stable isotopes and microalgae ecology
Estuarine Coastal and Shelf Science, 2008Co-Authors: Nathalie Malet, Pierre-guy Sauriau, Mireille Ryckaert, Pascale Malestroit, Gaël GuillouAbstract:Abstract The aim of this study was to distinguish between sources of the complex variety of Marennes-Oleron Bay suspended particulate organic matter (SPOM) contributing to the tropho-dynamics of the Marennes-Oleron Oyster Farming bay. Basic biomarkers (Chl a , C/N and POC/Chl a ratios), carbon and nitrogen stable isotopes from SPOM were analyzed and the microalgae community was characterized. The sampling strategy was bimonthly from March 2002 to December 2003; samples were taken from an intertidal mudflat. Four main sources contributed to the SPOM pool: terrigenous input from rivers, neritic phytoplankton, resuspended microphytobenthos and periodic inputs from intertidal Zostera noltii meadows. Seasonal fluctuations were observed in both years of the study period: (1) SPOM collected in the spring of 2002 (δ 13 C = −25‰ to −23‰) was mainly composed of fresh estuarine inputs; (2) SPOM from the summer and fall of 2002 and 2003 was predominantly neritic phytoplankton (δ 13 C = − 22‰ to −19‰); (3) SPOM from the winter of 2002, spring of 2003 and winter of 2003 (δ 13 C = −21 to −23‰) was composed of a mixture of decayed terrigenous river inputs and pelagic phytoplankton, which was predominantly resuspended microphytobenthos. In the summer of 2003—the warmest summer on record in southern France and Europe—SPOM was particularly enriched for 13 C, with δ 13 C values ranging from −14‰ to −12‰. Pulses in δ 13 C values, indicative of 13 C-enriched decaying materials, extended into the fall. These were attributed to benthic intertidal inputs, including both resuspended microphytobenthos and Z. noltii detritus. Changes in SPOM sources in Marennes-Oleron Bay may lead to differences in the quality of the trophic environment available for reared Oysters.
Laurent Barillé - One of the best experts on this subject based on the ideXlab platform.
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Remote sensing of suspended particulate matter in turbid Oyster‐Farming ecosystems
Journal of Geophysical Research: Oceans, 2014Co-Authors: Pierre Gernez, Laurent Barillé, Astrid Lerouxel, Constant Mazeran, Axel Lucas, David DoxaranAbstract:High resolution satellite data of the Medium Resolution Imaging Spectrometer in full resolution mode (MERIS FR, pixel size is 300 m) were used to study the impact of suspended particulate matter (SPM) on Oyster-Farming sites in a macrotidal bay of the French Atlantic coast where SPM concentration can exceed 100 g m−3. Because MERIS standard SPM concentration retrieval saturates at about 50 g m−3, we developed an alternative method for turbid nearshore waters. The method consists in the combination of the Semi-Analytical Atmospheric and Bio-Optical (SAABIO) atmospheric correction with a regional bio-optical algorithm based on a linear relationship between SPM concentration and the reflectance band ratio at 865 and 560 nm. MERIS FR-derived SPM concentrations were validated from 10 up to 300 g m−3, and then merged with Oyster ecophysiological responses to provide a spatial picture of the impact of SPM concentration on Oyster-Farming sites. Our approach demonstrates the potential of high resolution satellite remote sensing for aquaculture management and shellfish-Farming ecosystems studies.
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remote sensing of suspended particulate matter in turbid Oyster Farming ecosystems
Journal of Geophysical Research, 2014Co-Authors: Pierre Gernez, Laurent Barillé, Astrid Lerouxel, Constant Mazeran, Axel Lucas, David DoxaranAbstract:High resolution satellite data of the Medium Resolution Imaging Spectrometer in full resolution mode (MERIS FR, pixel size is 300 m) were used to study the impact of suspended particulate matter (SPM) on Oyster-Farming sites in a macrotidal bay of the French Atlantic coast where SPM concentration can exceed 100 g m−3. Because MERIS standard SPM concentration retrieval saturates at about 50 g m−3, we developed an alternative method for turbid nearshore waters. The method consists in the combination of the Semi-Analytical Atmospheric and Bio-Optical (SAABIO) atmospheric correction with a regional bio-optical algorithm based on a linear relationship between SPM concentration and the reflectance band ratio at 865 and 560 nm. MERIS FR-derived SPM concentrations were validated from 10 up to 300 g m−3, and then merged with Oyster ecophysiological responses to provide a spatial picture of the impact of SPM concentration on Oyster-Farming sites. Our approach demonstrates the potential of high resolution satellite remote sensing for aquaculture management and shellfish-Farming ecosystems studies.
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MODELING Oyster Farming ACTIVITIES IN COASTAL AREAS: A GENERIC FRAMEWORK AND PRELIMINARY APPLICATION TO A CASE STUDY
Coastal Management, 2012Co-Authors: Cyril Tissot, David Brosset, Laurent Barillé, Laurent Le Grel, Mathias Rouan, Tillier Ion, Matthieu Le TixerantAbstract:We present an approach for modeling Oyster Farming activities under spatio-temporal constraints. Combining an object-oriented geodatabase, a geographic information system and a multi-agent model, the methodology developed here offers a formal framework for analyzing the variability of the conditions in which activities are conducted and for evaluating how production systems adapt to this variability. A prototype specific to the Bay of Bourgneuf (France) was developed to study the spatio-temporal variability of Oyster growth according to the quality of coastal waters and the Oyster production strategy.
