ISSN: 2578-4994
Authors: Sakib Hasan Nion, Islam MS*, Enamul Hoq, Humayun Kabir and Mir Mozammal Hoque
The study was conducted to investigate the seasonal and tidal variations of physicochemical parameters, nutrient contents and chlorophyll a concentration from water of Passur river and Koromjol canal in the Sundarbans mangrove ecosystems during March 2018 to February 2019. Samples were collected from five sampling stations from during March, August and November where these months were considered as pre-monsoon, monsoon and post-monsoon seasons, respectively. Samples were analyzed in the laboratory of the Mawlana Bhashani Science and Technology University, Tangail and the Bangladesh Fisheries Research Institute, Mymensingh. In pre-monsoon, monsoon and post-monsoon seasons, the temperature, pH, DO, salinity, EC and TDS were ranged from 22.3 to 28.7ºC, 7.6 to 8.68, 7.85 to 13.13mg/l, 0.093 to 0.361%, 712 to 3257μs/cm and 306 to 3456ppm, respectively during high tides. During low tides, temperature, pH, DO, salinity, EC and TDS were ranged from 23.8 to 28.2ºC, 8.05 to 8.7, 7.45 to 14.39mg/l, 0.099 to 0.317%, 102 to 3857μs/cm and 213 to 3461ppm, respectively. The nutrients NH3-N, NO3-N, PO4-P, SO4 and Chlorophyll a concentrations were found 0.001 to 0.09, 3.5 to 50, 0.06 to 5.4, 30 to 272 and 0.18 to 1.75mg/l, respectively during high tides, and 0.001 to 0.39, 4.2 to 47, 0.1 to 2.75, 20 to 179 and 0.218 to 1.88mg/l, respectively during low tides. Temperature, EC and TDS were lower than suitable range at S1 to S3 during monsoon. Salinity concentrations of all stations were very low during both tides over three seasons. The NO3-N was very high than suitable limit during both tides at monsoon and postmonsoon. The PO4-P was found moderately high during both tides at all stations. The SO4 was found 187.8 and 76.87 mg/l during high tide, and 135.4 and 95.73 mg/l during low tides in pre-monsoon and post-monsoon, respectively; which were very high than suitable range of water quality. During low tide, mean concentration of chlorophyll a was 1.428 mg/l in post-monsoon, which was higher than monsoon (0.649 mg/l) and pre-monsoon (0.789 mg/l). The Passur river and the Koromjol canal are fluctuating seasonally and tidally in some magnitude and their variations can alter the water quality as well as living organisms; that would be a major concern in Sundarbans mangroves environment.
Keywords: Chlorophyll a; Nutrients Concentration; Sundarbans Mangrove Ecosystems
