Produtividade fitoplanctônica e hidrologia do ecossistema costeiro de Maracajaú - RN

Abstract

This paper refers to the first contribution about the phytoplankton community productivity related to the hydrological parameters of the coastal ecosystem of Maracajaú-RN, which is located 67 km North of Natal City. This is an important reef area named by the local inhabitants of “parrachos” a reef table type, which are located 6km from the coast and have a key ecological role in maintaining a typical reef fauna and flora, increasing the local biodiversity. Plankton and hydrological samples were collected at surface, during spring low tides, with a Van Dorn and Nansen bottles, respectively. Sampling were carried out in the dry (February and March/00) and in rainy (May and June/00) seasons in three fixed stations. The data showed that the studied ecosystem is free of organic pollution presenting high concentration of dissolved oxygen. Salinity, water transparence and suspended material indicated continental influence, mainly during the rainy season. The primary productivity varied between the two seasons being higher at the rainy season, varying the ecosystem from oligotrophic at the reef area to eutrophic close to the coast.