Comparison between phytoplankton bio-diversity and various indices for winter monsoon and inter monsoon periods in north-eastern Arabian Sea

Abstract

1513-1518<span style="font-size:11.0pt;font-family: " times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";mso-bidi-font-family:="" mangal;mso-ansi-language:en-gb;mso-fareast-language:en-us;mso-bidi-language:="" hi"="" lang="EN-GB">Phytoplankton samples of north-eastern Arabian Sea were collected during ocean colour satellite validation cruises from 2003-2007. Phytoplankton community organization and distribution was analyzed using various diversity indices like Shannon Diversity Index, Simpson Diversity Index, Margalef Diversity Index, McIntosh Diversity Index, Pielou Evenness Index and dominance index. Results showed that Navicula, Thalasiothrix and Rhizosolenia were most abundant among the diatoms. Trichodesmium, a cyanobacteria, dominated the shallow coastal waters. Resultant indices were correlated with phytoplankton cell counts and it was found that Shannons index better represents the diversity than other indices. Cell counts were also correlated with <i style="mso-bidi-font-style: normal">in situ chlorophyll-a values, which showed that this correlation does not stand good for the bloom conditions.</span