STRUCTURE AND DYNAMICS OF EPIPELIC ALGAE FROM A PLAIN RIVER (SAMBOROMBON RIVER, BUENOS-AIRES, ARGENTINA)

During March 1986-February 1987 the epipelic algal flora at 4 sites of the Samborombon River was investigated. A total of 137 species were d etermined. Diatoms and cyanophytes were the most important algae. The maximum density and species richness peaks were observed during autumn and winter. Diversity increased from the headwaters towards the mouth . Tidal waves influenced the epipelic community in the mouth of Sambor ombon River in the Rio de la Plata estuary and contributed to the diff erences observed among stations.