PHYTOPLANKTON DYNAMICS IN THE CIÉNAGA GRANDE DE SANTA MARTA, COLOMBIAN CARIBBEAN

Abstract

In order to assess phytoplankton dynamics in the Ciénaga Grande de Santa Marta, bimonthly sampling was done at six stations from March 1996 to February 1997. Salinity showed wide ranges so the year could be divided in four seasons. Higher salinities were related to higher phytoplankton density, while lower salinities were related to lower phytoplankton densities and increased species richness. 224 taxa were recorded, and the general trend was towards a low diversity with a few dominant species, and most of them rare. Cyanophytes showed the highest abundances all year. Salinity, turbidity and orthophosphates were the environmental factors best related to the biotic data. Seasonal changes in phytoplankton concerning to meteorological conditions, fresh and tidal floods and dredging of Clarín canal are discussed.