Diversity and distribution of phytoplankton at Verem (Mandovi estuary) Goa

Abstract

To understand diversity, distribution and the effect of environmental factors on phytoplankton, samples were collected fortnightly at Verem station in the Mandovi estuary during monsoon and non-monsoon period from June 2008 to May 2009. Study examined taxonomic composition, abundance and spatial distribution of phytoplankton. Highest biomass was reported during the nonmonsoon season ranged between 1.09-5.62 mg m sup(-3) average of 2.43 mg m sup(-3) and phytoplankton cell density ranged from 0.05-7.00 X 10 sup(4)/L an average of 0.57 X 104/L. Altogether, 125 species of phytoplankton were reported during monsoon and 93 species during non-monsoon period. The highest numbers of species (125) consists of diatoms, dinoflagellates and other algae accounting for 90, 31 and 4 species respectively. Diatoms were the major taxonomic group accounting for between 78 and 82 percent of the total population. Diversity index (H') and evenness (J) were 4.20 and 0.78 in the monsoon season, and 3.81 and 0.73 in non-monsoon. The CCA analysis showed that the environmental parameters like salinity, nutrients and rainfall has greater influence on the distribution of phytoplankton species. It can be confirmed from this findings that monsoon acts as a major player in the temporal distribution of phytoplankton. Salinity and nutrients are the governing factors in the growth of the phytoplankton.