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| Mai, Tepoerau; Toullec, Jordan; Van Wynsberge, Simon; Besson, Marc; Soulet, Stephanie; Petek, Sylvain; Aliotti, Emmanuelle; Ekins, Merrick; Hall, Kathryn; Erpenbeck, Dirk; Lecchini, David; Beniddir, Mehdi A.; Saulnier, Denis; Debitus, Cecile. |
| Marine natural products isolated from the sponge Fascaplysinopsis cf reticulata, in French Polynesia, were investigated as an alternative to antibiotics to control pathogens in aquaculture. The overuse of antibiotics in aquaculture is largely considered to be an environmental pollution, because it supports the transfer of antibiotic resistance genes within the aquatic environment. One environmentally friendly alternative to antibiotics is the use of quorum sensing inhibitors (QSIs). Quorum sensing (QS) is a regulatory mechanism in bacteria which control virulence factors through the secretion of autoinducers (AIs), such as acyl-homoserine lactone (AHL) in gram-negative bacteria. Vibrio harveyi QS is controlled through three parallel pathways: HAI-1, AI-2,... |
| Tipo: Text |
Palavras-chave: Porifera; Marine natural products; Quorum sensing inhibitors; Antibiotic; Fascaplysinopsis cf reticulata. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00598/71052/69366.pdf |
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| Menoud, Mathilde; Van Wynsberge, Simon; Le Moullac, Gilles; Levy, Peva; Andrefouet, Serge; Remoissenet, Georges; Gaertner-mazouni, Nabila. |
| Monitoring gonadmaturation for protandrous and functional hermaphrodite species such as the giant clamTridacna maxima is difficult due to the juxtaposition and relative proportion ofmale and female tissues in the gonad [gonadal sex ratio (GSR)]. Here, the relevance of the widely used gonadosomatic index (GSI) as proxy of giant clam gonad maturation is tested with a large dataset (n = 265). Gonadosomatic index is compared with other indices, namely the proportion of the male part harboring spermatozoids, the proportion of empty oocyte follicles, the mean oocyte diameter, and the oocyte elongation. At gonad scale, high index variability highlighted partial spawning. At individual scale, male and female maturation proxies were contrasted, showing either... |
| Tipo: Text |
Palavras-chave: Giant clam; Marine bivalve; Reproduction; Spawn; Tatakoto atoll; Histology; Tridacna maxima. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00333/44441/44111.pdf |
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| Brisset, Maele; Van Wynsberge, Simon; Andréfouët, Serge; Payri, Claude; Soulard, Benoit; Bourassin, Emmanuel; Le Gendre, Romain; Coutures, Emmanuel. |
| Despite the necessary trade-offs between spatial and temporal resolution, remote sensing is an effective approach to monitor macroalgae blooms, understand their origins and anticipate their developments. Monitoring of small tropical lagoons is challenging because they require high resolutions. Since 2017, the Sentinel-2 satellites has provided new perspectives, and the feasibility of monitoring green algae blooms was investigated in this study. In the Poé-Gouaro-Déva lagoon, New Caledonia, recent Ulva blooms are the cause of significant nuisances when beaching. Spectral indices using the blue and green spectral bands were confronted with field observations of algal abundances using images concurrent with fieldwork. Depending on seabed compositions and... |
| Tipo: Text |
Palavras-chave: Ulva; Sentinel-2; Satellite; Remote sensing; Algal bloom; Coral reefs; Pacific lagoons. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00668/77968/80184.pdf |
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| Van Wynsberge, Simon; Andrefouet, Serge; Gaertner-mazouni, Nabila; Tiavouane, Josina; Grulois, Daphne; Lefevre, Jerome; Pinsky, Malin L.; Fauvelot, Cecile. |
| Previous seascape genetics studies have emphasized the role of ocean currents and geographic distances to explain the genetic structure of marine species, but the role of benthic habitat has been more rarely considered. Here, we compared the population genetic structure observed in West Pacific giant clam populations against model simulations that accounted habitat composition and configuration, geographical distance, and oceanic currents. Dispersal determined by geographical distance provided a modelled genetic structure in better agreement with the observations than dispersal by oceanic currents, possibly due to insufficient spatial resolution of available oceanographic and coastal circulation models. Considering both habitat composition and... |
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| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00387/49791/50345.pdf |
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| Van Wynsberge, Simon; Andrefouet, Serge; Gaertner-mazouni, Nabila; Wabnitz, Colette C. C.; Menoud, Mathilde; Le Moullac, Gilles; Levy, Peva; Gilbert, Antoine; Remoissenet, Georges. |
| Shell growth, reproduction, and natural mortality of the giant clam Tridacna maxima were characterized over a two-year-period in the lagoon of the high island of Tubuai (Austral Archipelago) and in the semi-closed lagoon of Tatakoto (Tuamotu Archipelago) in French Polynesia. We also recorded temperature, water level, tidal slope, tidal range, and mean wave height in both lagoons. Lower lagoon aperture and exposure to oceanic swells at Tatakoto than at Tubuai was responsible for lower lagoon water renewal, as well as higher variability in temperature and water level at Tatakoto across the studied period. These different environmental conditions had an impact on giant clams. Firstly, spawning events in the lagoon of Tatakoto, detected by gonad maturity... |
| Tipo: Text |
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| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00371/48214/48335.pdf |
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| Van Wynsberge, Simon; Menkes, Christophe; Le Gendre, Romain; Passfield, Teuru; Andrefouet, Serge. |
| In remote coral reef environments, lagoon and reef in situ measurements of temperature are scarce. Sea Surface Temperature (SST) measured by satellite has been frequently used as a proxy of the lagoon temperature experienced by coral reef organisms (TL) especially during coral bleaching events. However, the link between SST and TL is poorly characterized. First, we compared the correlation between various SST series and TL from 2012 to 2016 in three atolls and one island in the Central South Pacific Ocean. Simple linear correlation between SST and TL ranged between 0.44 and 0.97 depending on lagoons, localities of sensors, and type of SST data. High-resolution-satellite-measurements of SST inside the lagoons did not outperform oceanic SST series,... |
| Tipo: Text |
Palavras-chave: Atoll lagoon; Pacific islands; Reef aperture; Climate change; Sea Surface Temperature. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00403/51491/52087.pdf |
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