Phytoplankton Community Structure and Seasonality in a Tropical Mangrove Estuarine and Coastal Waters, South China Sea

Phytoplankton are the primary producer of the food chain in any aquatic ecosystem, and play a crucial role in maintaining fishery resources. The community structure of phytoplankton in tropical mangrove estuarine and adjacent coastal waters was investigated in the South China Sea from January 2013 to December 2013 to compare the significance of two water bodies. Study revealed, 102 species of phytoplankton species under 43 genera covering 6 species of Cyanophyceae, 4 species of Chlorophyceae, 63 species of Bacillariophyceae and 29 species of Dinophyceae from estuarine mangrove area. Whereas 67 species from coastal waters were recorded which comprised of 47 species of Bacillariophyceae, 16 species of Dinophyceae, 2 species of Cyanophyceae with 1 species of both the Dictyochophyceae and Chrysophyceae. The phytoplankton community structure and mean abundance (cells/L) were recorded in a systematic order of Bacillariophyceae > Dinophyceae > Cyanophyceae > Chlorophyceae in mangrove waters. While from coastal waters the systematic order was found as Bacillariophyceae > Dinophyceae > Cyanophyceae > Dictyochophyceae > Chrysophyceae. Phytoplankton mean abundance fluctuated from 567 to 88,890 cells/L in different seasons over the study period with its higher value in the dry season. The mean phytoplankton cell abundance in mangrove estuarine area (38,313.74 ± 5614.26) found significantly ( p