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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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| Barille, Laurent; Lerouxel, Astrid; Dutertre, Mickael; Haure, Joel; Barille, Anne-laure; Pouvreau, Stephane; Alunno-bruscia, Marianne. |
| We compared growth simulations by dynamic energy budget (DEB) and scope for growth (SFG) models of the Pacific oyster Crassostrea gigas, cultivated in Bourgneuf Bay on the French Atlantic coast. This bay is located at a latitude in the middle of the European range of the species, and is characterized by high concentrations of suspended particulate matter (SPM) and a marked gradient between high-turbidity sites in the north (daily SPM > 500 mg L-1) and intermediate-turbidity sites in the south. The models use two forcing variables: seawater temperature and food density. We tested two indices of food availability: chlorophyll a and microalgal concentrations. In the SFG model, food intake is simulated by a type-II Holling functional response, as in the DEB... |
| Tipo: Text |
Palavras-chave: Oyster; Dynamic Energy Budget model; Scope for growth model; Turbidity. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00043/15433/12783.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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| Savelli, Raphael; Dupuy, Christine; Barille, Laurent; Lerouxel, Astrid; Guizien, Katell; Philippe, Anne; Bocher, Pierrick; Polsenaere, Pierre; Le Fouest, Vincent. |
| Microphytobenthos (MPB) from intertidal mudflats are key primary producers at the land–ocean interface. MPB can be more productive than phytoplankton and sustain both benthic and pelagic higher trophic levels. The objective of this study is to assess the contribution of light, mud temperature, and gastropod Peringia ulvae grazing pressure in shaping the seasonal MPB dynamics on the Brouage mudflat (NW France). We use a physical–biological coupled model applied to the sediment first centimetre for the year 2008. The simulated data compare to observations, including time-coincident remotely sensed and in situ data. The model suggests an MPB annual cycle characterised by a main spring bloom, a biomass depression in summer, and a moderate fall bloom. In early... |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00471/58226/60732.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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