Phytoplankton and Nutrient Dynamics of a Tropical Estuarine System, Imo River Estuary, Nigeria

Abstract

This paper reported a fifteen month study of the patterns of variation of
phytoplankton, physical and chemical characteristics of the Imo River estuary between April 2001 and June 2002 were reported. There were remarkable spatial and temporal variations of physico-chemical parameters and significant difference in the stations (p< 0.05). A wide array of phytoplankton species distributed in 221 taxa, 85 genera, 37 families, 16 orders in 7 divisions; with chlorophyta > bacillariophyta > Cyanophyta > Dinophyta > Euglenophyta > Chrysophyta > Rhodophyta. Phytoplankton density and diversity were highest in the brackish water, mesohaline zone of the estuary. The trend of wet season nutrient enrichment was observed and maximum phytoplankton concentration was however not coincidental with nutrient enrichment. Early dry season assemblages were characterized by
relatively large number of chlorophyta and pennate diatoms in the freshwater and brackishwater zones of the estuary. The dynamic throughput of the estuary is a function of seasonal nutrient input and the effect of the adjacent sea on the estuary.

African Research Review Vol. 2 (2) 2008 pp. 253-264