Estuaries are transitional zone between river and sea responsible for providing nutrient rich environment for the ecologically and economically important vertebrates and non vertebrate species. Patalganga Estuary that joins with Amba River and Karanja Creek, is a productive ecosystem in terms of plankton, molluscs and ichthyofauna. Local fishermen are dependent on the estuarine functions and services of the estuary for their wellbeing. Therefore to know the health status, monthly analysis for water quality parameters including dissolved oxygen (DO), biological oxygen demand (BOD), temperature, pH, salinity, chlorophyll-a (chl-a), gross and net primary productivity (GPP and NPP) and water nutrients like ammonia-nitrogen (NH3-N), nitrite-nitrogen (NO2- -N), nitrate-nitrogen (NO3- -N) and available phosphate (PO4), were conducted. The analysis revealed temporal variations in water quality parameters. (DO range from 2.4 to 8.6 mgL-1, BOD:0.8 to 4.8 mgL-1, NH3-N: 0.04 to 0.19 mgL-1, NO2- -N: 0.06 to 1.49 mgL-1, NO3- -N: 0.002 to 0.039 mgL-1, PO4: 0.34 to 0.70 mgL-1, Temperature: 20.0 to 33.0 0C, pH: 6.9 to 8.8, salinity: 0.00 to 40.0 ppt, chl-a: 0.02 to 23.4 mg m-3, NPP: 13.2 to 166.7 mgCm-3day-1, GPP: 40 to 300 mgCm-3day-1). Plankton diversity included 33 genera of diatom, 7 dinoflagellates, and 7 other algae including Chlorella sp, Microcystis spp, Paediastrum spp, Scenedesmus spp and Staurastrum spp, and 14 groups of zooplankton. More than 40 species of fishes, 13 species of shrimps, 7 species of crabs and 3 species of cephalopods were also observed.
Patalganga estuarine ecosystem is threatened with many anthropogenic factors like intense navigation, sand mining, construction of Karanja boat jetty, dredging, industrial effluents, sewage discharges and plastic pollution. Along with this, tidal water from Thane creek also carries pollutants. Present study indicated a gradual decline in production and productivity of the estuarine ecosystem. Hence continuous study is required to know the gradual changes taking place in the ecosystem, which provides livelihood to thousands of fishers and the ecosystem services.