Abstract

Mangroves are hotspots of primary production which act as a buffer between marine and terrestrial environment. They shelter a unique ecosystem characterized by an exceptional biodiversity. In Guadeloupe, mangroves spread over 3000 hectares. Presently the mangrove ecosystem of Guadeloupe is under serious threat because many anthropogenic activities are concentrated on the coastline and contribute to the contamination of the whole coastal ecosystems by polluting substances. Biomarkers have become valuable ecotoxicological tools to assess the toxicity and bioavailability of pollutants. In this study, two approaches are used to evaluate the importance of damage caused to mangroves ecosystem. The first one is the quantification of the pollutants (heavy metals, polyaromatics hydrocarbons and pesticides) notably in sentinel species (Crassostrea rhizophorae) and the second one is the measure of the impact on natural populations by using a biomarker of genotoxicity. Here we present an adaptation of this biomarker to assess DNA damage in different species as mangrove oysters (Crassostrea rhizophorae) and fishes (Ocyurus chrysurus). The quantification of DNA single strand breaks (SSB) by the comet assay can be used as a rapid and sensitive indicator of genotoxicant exposure. The xenobiotic concentrations should be correlated to comet assay results in order to locate risk zone. At present, complementary monitoring studies targeting other biomarkers of oxidative stress (catalase, GST, TBARS) are carried out to assess more precisely the impact of contamination of guadeloupean mangroves by human activities.

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