Phytoplankton Distribution in Estuarine and Coastal Waters of Mumbai

Abstract

Neretic and near shore subtropical biodiversity includes phytoplankton, zooplankton, Benthos, sea weeds and mangroves in the coastal region of the country.  Among many coastal ecosystems studied, one is Ulhas river estuary-Vasai creek - Thane creek (Thane) adjoining Rewas creek-Karanja creek (which receives water from Amba river, Patalganga river and Bhogwati river towards Uran-Mandve village side) in coastal waters of Mumbai.  Small rivers Ulhas river, Mithi river are present at west coast forming estuarine systems in coastal region of Mumbai. Coastal water receives approximately 1800 MLD of sewage water which affects assimilative capacity of coastal waters. The phytoplankton distribution study was conducted during three seasons viz. premonsoon, aftermonsoon and postmonsoon seasons 2007-08. Phytoplankton 19 species, 18 species and 27 species and diatoms as dominant group were observed at 16 sampling stations of 4 transects in coastal waters (nearshore, 1km, 3km, and 5km distance from shore) in premonsoon, after monsoon and post monsoon. Freshwater, salinity tolerant and marine water phytoplankton species   Klebsormidium elagans, Navicula petersenii, Nitzschia seriata, Thalassiothrix longissima, Coscinodiscus radiatus, Gyrosigma balticum were  recorded in estuarine and coastal waters. Moderate values of Shannon wiener diversity index were observed in surface waters of estuary and coastal waters.  Simpson index of species dominance was decreased in estuarine water during high tide though the dominated phytoplankton species belong to marine phytoplankton. Maximum phytoplankton numbers 27900/l (TC8W-premonsoon), 18180/l (TC9W-monsoon) and 104000/l (TC6W-postmonsoon) were observed in estuarine waters. Dominance of  Klebsormidium elagans (chlorophyceae) was observed in estuarine waters from sampling stations 1 to 13 (East, Center, West of the sampling stations). Scattered digram of phytoplankton species distribution in coastal water and two ways ANOVA had shown seasonal variations of phytoplankton in coastal waters.