Phytoplankton species diversity indices in Anjanapura reservoir, Western Ghat region, India.

ABSTRACT

A qualitative study on species composition and diversity of phytoplankton flora was carried out in the Anjanapura reservoir. Water samples were collected monthly at four sites from November 2005 to October 2007 for plankton analysis. A total of 152 phytoplankton species belonging to 59 genera were recorded. The species belonging to genera Crucigenia, Pediastrum, Scenedesmus, Tetraedron, Cyclotella, Gyrosigma, Melosira, Navicula, Fragillaria, pinnularia, Synedra, Closterium, Cosmarium, Euastrum, Staurastrum, Gleocapsa, Merismopedia, Microcystis,Oscillatoria, Euglena and Phacus were found dominant. Phytoplankton density was recorded in the range of 222-1467 Org l-1 for chlorococcales, 267-1467 Org l-1 for diatoms, 44-889 Org l-1 for desmids, 44-889 Org l-1 for blue-greens and 22-1667 Org l-1 for euglenoids. Seasonal density Shannon-Weiner diversity index (1.60-1.88) indicate that reservoir exhibited rich phytoplankton and Nygaard tropic status indices for myxophycean(1.0-1.50), chlorophycean(1.62-2.16), diatoms(0.10-0.14), euglenophycean(0.18-0.19) and compound quotient(3.25-4.66) showed that reservoir was moderately polluted. From the observed data, it could be concluded that the presence of more diverse group of phytoplankton indicate the productivity of the reservoir.