|
|
Bouchon, Claude; Lemoine, Soazig; Wetzel, Dana; Reynolds, John E., III; Bouchon-Navaro, Yolande; Cordonnier, Sebastien; Louis, Max
(detail)
|
| |
|
2010 |
Level of contamination by metallic trace elements and organic molecules in the seagrass beds of Guadeloupe Island.
Proceedings of the Gulf and Caribbean Fisheries Institute 63: 505a. Nov. 2010.
–ABSTRACT: In terms of area of extent, seagrass beds represent the main marine coastal ecosystem in the French West Indies. They also constitute nurseries for many invertebrates and fishes harvested by local fisheries. In Guadeloupe, coastal fish stocks are declining; concurrently, some agricultural areas, rivers, and mangroves areas have been shown to be heavily contaminated by pollutants. Moreover, the National Park of Guadeloupe plans to re-introduce West Indian manatees in the Grand Cul-de-Sac Marin Bay (GCSM), from which they disappeared at the beginning of the last century. Considering these facts, a study of contamination of the seagrass beds (8,000 ha) of GCSM was conducted on both sediments and marine phanerogams (Thalassia testudinum and Syringodium filiforme). The analyses concerned 6 metals (Cd, Cu, Hg, Pb, V, Zn), tributyltin, 18 polycyclic aromatic hydrocarbons (PAHs), 8 polybrominated diphenyl ethers (PBDEs), 38 polychlorobiphenyls (PCBs), dithiocarbamates (CS2 residues) and 225 pesticide molecules. In general, the level of contamination of the seagrass beds was low for both sediments and phanerogams. Metallic trace elements were the main pollutants, but their locations remained coastal and meir distribution can be explained by proximity to river mouths and current patterns. The level of contamination was lower in plants than in sediments; however, the level of contamination between these two compartments was significantly correlated. In conclusion, the level of contamination of the GCSM seagrass beds is low and does not appear to be a risk factor for fish and shellfish nurseries or grazing manatees.
|
|
|
Lacas, Sophie; Bouchon-Navaro, Yolande; Cordonnier, Sebastien; Bouchon, Claude
(detail)
|
| |
|
2010 |
Primary production dynamics of Thalassia testudinum (Konig) seagrass beds in Guadeloupe Island, FWI.
Proceedings of the Gulf and Caribbean Fisheries Institute 63: 508a. Nov. 2010.
–ABSTRACT: The present work was realized in the framework of the project of the National Park of Guadeloupe of reintroduction of the manatee (Trichechus manatus). The aim was to study the dynamics of the leaf primary production, the associated litter and its micro-fauna in Thalassia testudinum seagrass beds in order to evaluate the potential grazing impact of manatees. According to sites, the leaf primary production fluctuated between 2.6 plus or minus 0.4 g to 4.0 plus or minus 0.7 g of dry weight/m(2)/day in the absence of grazing and between 0.9 plus or minus 0.3 g and 1.4 plus or minus 0.4 g of dry weight/m(2)/day when cutting the leaves to simulate manatees "grazing". Moreover, areas 50 cm x 50 cm were completely denuded from leaves and rhizomes to simulate the "rooting" by manatees. These areas have not recovered after three months. The average mass of leaf litter fluctuates between 36.12 plus or minus 7.5 g dry weight/m(2) and 6.2 plus or minus 0.9 g dry weight/m(2). According to sites, the decay of litter reached 82% and 69.6% in three months. The fauna associated with litter consisted mainly of polychaetes, crustaceans, plathelminths and nematodes, which constitute an important link in the seagrass food web. Results from this study show that manatees grazing might disturb the primary productivity of seagrass beds. It will be necessary to be careful in the choice of areas of acclimation in terms of surface and duration of use, and in the choice of the number of manatees that can be reintroduced in the seagrass habitats.
|
|
Bibliography and Index of the Sirenia and Desmostylia 