Spatio-temporal Distribution and Biochemical Composition of Phytoplankton along the Coastal Waters of Dakshin Kannada District, Karnataka, India

Abstract

The phytoplankton distribution and biochemical composition concerning water quality parameters were studied in the coastal waters off Mangalore, Monthly sampling was carried out from October 2020 to May 2022 at selected stations of Netravathi-Gurupura estuary, latitude 12°50'38.56" N, longitude 74°50'0.23° to coastal waters off Padubidri latitude 13° 8'0. 57" N longitude 74°42'9.47° with an average depth of 8 meters. Spatiotemporally the phytoplankton, chlorophyll-a and phytoplankton biochemical composition showed a significant difference for the entire duration. During the present investigation, 35 different phytoplankton genera belonging to 3 groups were observed with complete domination from diatoms with 27 genera followed by Dinoflagellates 7 and blue-green algae. distribution and abundance of the phytoplankton were mainly Chaetoceros sp., Ceratium sp., Thallasiocera sp., Biddulphia sp., Coscinodiscus sp., Rhizosolenia sp., Ditylum sp., Triceratium sp., Nitzschia sp. and blue-green algae under Chrysophyta, Bryophyta, Chlorophyta, Cyanophyta were observed, while in biochemical composition of phytoplankton, the carbon contributed to the highest percentage and hydrogen constitute to the lowest percentage. Crude protein and Lipid contents are maximum during post-monsoon and carbohydrates showed their highest content during pre-monsoon for phytoplankton. There is a direct relationship between the biochemical composition and the physiochemical and environmental conditions including nutrients, especially nitrates and phosphates.