TROPHIC STATUS OF A TROPICAL COASTAL LAGOON IN MARGARITA ISLAND, VENEZUELA

Punta de Piedras Lagoon is a coastal lagoon located south of Margarita Island, in the Venezuelan Caribbean Sea. This lagoon has ecological and economic importance for the inhabitants of nearby communities. Currently, the urban and industrial development in its surroundings represents a potential source of pollutants, providing concentrations of nutrients that could affect the ecological balance of the area. The trophic status of Punta de Piedras Lagoon was evaluated using various trophic indices. The concentrations of chlorophyll -a and nutrients (ammonium, nitrites, nitrates, and orthophosphates) were estimated in 10 stations with a monthly frequency from February 2005 to January 2006. These data were used to estimate the trophic condition based on the Karydis and TRIX trophic indices, and by comparison with Organization for Economic Co-operation and Development reference values. It was found that Punta de Piedras lagoon presented mesotrophic conditions in most of the water body having considerable differences between indices. The values of the closest station to Paseo Esther Gil corresponded to eutrophic waters. However, the circulation and residence time of water allow an exchange with the adjacent sea, which prevents the eutrophication process in the lagoon.

Automated summary

Punta de Piedras Lagoon, located south of Margarita Island in the Venezuelan Caribbean Sea, is an important coastal lagoon with ecological and economic significance for nearby communities. The lagoon was found to have mesotrophic conditions with considerable differences between trophic indices, although the station closest to Paseo Esther Gil showed eutrophic waters. However, the circulation and residence time of water prevent the eutrophication process in the lagoon due to exchange with the adjacent sea.