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| Novoa, Stefani; Doxaran, David; Ody, Anouck; Vanhellemont, Quinten; Lafon, Virginie; Lubac, Bertrand; Gernez, Pierre. |
| The accurate measurement of suspended particulate matter (SPM) concentrations in coastal waters is of crucial importance for ecosystem studies, sediment transport monitoring, and assessment of anthropogenic impacts in the coastal ocean. Ocean color remote sensing is an efficient tool to monitor SPM spatio-temporal variability in coastal waters. However, near-shore satellite images are complex to correct for atmospheric effects due to the proximity of land and to the high level of reflectance caused by high SPM concentrations in the visible and near-infrared spectral regions. The water reflectance signal ((w)) tends to saturate at short visible wavelengths when the SPM concentration increases. Using a comprehensive dataset of high-resolution satellite... |
| Tipo: Text |
Palavras-chave: Remote sensing; Suspended particulate matter; Coastal waters; River plumes; Multi-conditional algorithm. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00590/70197/68222.pdf |
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| Barillé, Laurent; Bris, Anthony Le; Goulletquer, Philippe; Thomas, Yoann; Glize, Philippe; Kane, Frank; Falconer, Lynne; Guillotreau, Patrice; Trouillet, Brice; Palmer, Stéphanie; Gernez, Pierre. |
| Oyster production has historically taken place in intertidal zones, and shellfish farms already occupy large extents of the French intertidal space. The expansion of French shellfish aquaculture within intertidal areas is therefore spatially limited, and moving production to the subtidal offshore environment is considered to be a possible solution to this problem. Finding new sites along the French Atlantic coast was studied here from the perspective of small oyster companies run by young farmers, who are interested in offshore bivalve aquaculture expansion compatible with their investment capacity. In assessing the feasibility of such offshore production, we considered three main issues: (1) bivalve growth potential and (2) technical feasibility and... |
| Tipo: Text |
Palavras-chave: Pacific oyster; Site selection; Off-shore aquaculture; Remote sensing; Dynamic energy budget (DEB) model. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00606/71819/70593.pdf |
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| Pernet, Fabrice; Fuhrmann, Marine; Petton, Bruno; Mazurie, Joseph; Bouget, Jean-francois; Fleury, Elodie; Daigle, Gaetan; Gernez, Pierre. |
| Marine diseases have major impacts on ecosystems and economic consequences for aquaculture and fisheries. Understanding origin, spread and risk factors of disease is crucial for management, but data in the ocean are limited compared to the terrestrial environment. Here we investigated how the marine environment drives the spread of viral disease outbreak affecting The Pacific oyster worldwide by using a spatial epidemiology framework. We collected environmental and oyster health data at 46 sites spread over an area of 300 km2 along an inshore-offshore gradient during an epizootic event and conducted risk analysis. We found that disease broke out in the intertidal farming area and spread seaward. Mortalities and virus detection were observed in oysters... |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00450/56130/57670.pdf |
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| Ribeiro, Lourenço; Le Bris, Anthony; Hernandez Farinas, Tania; Buchet, Remi; Dutertre, Mickaël; Metzger, Edouard; Rosa, Philippe; Gernez, Pierre; Lerouxel, Astrid; Barille, Laurent. |
| In order to establish the ecological status of water bodies, the European Water Framework Directive (WFD) is based on the evaluation of a number of biological quality elements, as well as physical parameters supporting the biology. In estuaries, phytoplankton monitoring was not considered relevant because of the high turbidity characterizing the large metropolitan estuaries and the French overseas departments (Guyana). In this work, we considered the possibility of using microphytobenthos (MPB) as a biological indicator of the ecological status of estuaries. This activity report summarizes the actions undertaken in 2017 under an AFB / Université de Nantes convention, which is structured around two main axes: the first axis is based on the analysis of the... |
| Tipo: Text |
Palavras-chave: DCE; Diatomées benthiques; Diversité; Estuaires; Facteurs naturels; Gradient de perturbation; Loire; Bio-indication; Microphytobenthos; Pressions anthropiques; Télédétection.; Anthropogenic pressures; Benthic diatoms; Bio-indication; Diversity; Estuary; Loire; Microphytobenthos; Natural factors; Perturbation gradient; Remote sensing; WFD. |
| Ano: 2018 |
URL: http://archimer.ifremer.fr/doc/00446/55725/57376.pdf |
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| Thomas, Yoann; Pouvreau, Stephane; Alunno-bruscia, Marianne; Barille, Laurent; Gohin, Francis; Bryere, Philippe; Gernez, Pierre. |
| Aim The spread of non-indigenous species in marine ecosystems world-wide is one of today's most serious environmental concerns. Using mechanistic modelling, we investigated how global change relates to the invasion of European coasts by a non-native marine invertebrate, the Pacific oyster Crassostrea gigas. Location Bourgneuf Bay on the French Atlantic coast was considered as the northern boundary of C. gigas expansion at the time of its introduction to Europe in the 1970s. From this latitudinal reference, variations in the spatial distribution of the C. gigas reproductive niche were analysed along the north-western European coast from Gibraltar to Norway. Methods The effects of environmental variations on C. gigas physiology and phenology were studied... |
| Tipo: Text |
Palavras-chave: Biogeographical range expansion; Crassostrea gigas; DEB model; European coasts; Functional traits; Global change; Individual-based model; Invasive species; Remote-sensing. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00287/39828/38459.pdf |
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| Méléder, Vona; Savelli, Raphael; Barnett, Alexandre; Polsenaere, Pierre; Gernez, Pierre; Cugier, Philippe; Lerouxel, Astrid; Le Bris, Anthony; Dupuy, Christine; Le Fouest, Vincent; Lavaud, Johann. |
| The gross primary production (GPP) of intertidal mudflat microphytobenthos supports important ecosystem services such as shoreline stabilization and food production, and it contributes to blue carbon. However, monitoring microphytobenthos GPP over a long-term and large spatial scale is rendered difficult by its high temporal and spatial variability. To overcome this issue, we developed an algorithm to map microphytobenthos GPP in which the following are coupled: (i) NDVI maps derived from high spatial resolution satellite images (SPOT6 or Pléiades), estimating the horizontal distribution of the microphytobenthos biomass; (ii) emersion time, photosynthetically active radiation (PAR), and mud surface temperature simulated from the physical model MARS-3D;... |
| Tipo: Text |
Palavras-chave: Microphytobenthos; Intertidal mudflat; Gross primary production; Remote sensing; NDVI; Modeling. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00643/75531/76429.pdf |
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| Thomas, Yoann; Cassou, Christophe; Gernez, Pierre; Pouvreau, Stephane. |
| Beyond key ecological services, marine resources are crucial for human food security and socio-economical sustainability. Among them, shellfish aquaculture and fishing are of primary importance but become more vulnerable under anthropogenic pressure, as evidenced by reported mass mortality events linked to global changes such as ocean warming and acidification, chemical contamination, and diseases. Understanding climate-related risks is a vital objective for conservation strategies, ecosystems management and human health. We provide here a comprehensive study of the historical mortality of adult oysters related to observed climate variability along the French Atlantic coast from 1986 to 2015, and we built on this knowledge to develop hindcast and forecast... |
| Tipo: Text |
Palavras-chave: North Atlantic; Weather regime; Oyster; Monitoring network; Mortality risk assessment; Climate models; RCP scenarios. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00461/57255/59281.pdf |
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| Gernez, Pierre; Lafon, Virginie; Lerouxel, Astrid; Curti, Cecile; Lubac, Bertrand; Cerisier, Sylvain; Barille, Laurent. |
| At the end of the SPOT4 mission, a four-month experiment was conducted in 2013 to acquire high spatial (20 m) and high temporal (5 days) resolution satellite data. In addition to the SPOT4 (Take5) dataset, we used several Landsat5, 7, 8 images to document the variations in suspended particulate matter (SPM) concentration in the turbid Gironde and Loire estuaries (France). Satellite-derived SPM concentration was validated using automated in situ turbidity measurements from two monitoring networks. The combination of a multi-temporal atmospheric correction method with a near-infrared to visible reflectance band ratio made it possible to quantify SPM surface concentration in moderately to extremely turbid waters (38-4320 g center dot m(-3)), at an accuracy... |
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| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00590/70198/68221.pdf |
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