Cuet,-P.; Naim,-O.; Faure,-G.; Conan,-J.-Y. Nutrient-rich groundwater impact on benthic communities of La Saline fringing reef (Reunion Island, Indian Ocean): Preliminary results. PROCEEDINGS-OF-THE-SIXTH- INTERNATIONAL-CORAL-REEF-SYMPOSIUM,-TOWNSVILLE,- AUSTRALIA,-8th-12th-AUGUST-1988.-VOLUME-2:-CONTRIBUTED- PAPERS-MINI-SYMPOSIUM-1-TO-10-14. Choat,-J.H.;Barnes,- D.;Borowitzka,-M.A.;Coll,-J.C.;Davies,-P.J.;et-al.-eds.. 1988. pp. 207-212. On La Saline Reef, fleshy algae facies have been observed to outcompete the flourishing coral communities recorded in the 1970's. Consequently, submarine groundwater discharge (SGD) has been supposed to enrich lagoonal waters in nutrients. Good agreement between 2 maps, respectively corresponding to freshwater and benthic communities distributional patterns, gives strong evidence that a relationship exists between SGD extension and degradation of La Saline coral communities. As freshwater is likely to provide N-enrichment to reefal waters, as shown by the linear relationship existing between NO sub(3) super(-) and reactive silicate, possible influence of PO sub(4) super(3-) high concentrations (up to 0.6 mu M) is discussed. Relevant bioerosion effects and undergrazing are noticed. Bleaching events and eventual impact of low tide phases are mentioned.