- Dona Paula, Goa, India.
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| Abstract Submission No. | ABS-2022-09-0343 |
| Title of Abstract | Water quality in response to semidiurnal tides in Mahanadi Estuary, East cost of India |
| Authors | Aneesh Lotliker*, S.K. Baliarsingh, Rajdeep Roy |
| Organisation | Indian National Centre for Ocean Information Services (INCOIS) |
| Address | Indian National Centre for Ocean Information Services (INCOIS) Hyderabad, Telangana, India Pincode: 500090 Mobile: 9703669046 E-mail: aneesh@incois.gov.in |
| Country | India |
| Presentation | Oral |
| Abstract | The third largest in the peninsular India, Mahanadi River, introduces large amount of anthropogenic flux in the northern part of coastal Bay of Bengal. The Mahanadi River receives effluents from different industrial and urban centers. The nearby fishing jetty close to the estuarine mouth adds certain source of pollutants to the near coastal area. It also receives a large amount of agricultural run-off along its course. The studies also reports fresh water influx from the estuary influences the coastal water more than 43 km off coast. A programmatically focused comprehensive study was carried out to decipher the variability of physico-chemical and biological variables over a period of semidiurnal tidal cycle during post-monsoon of 2018 in Mahanadi estuary. Two locations (upstream and downstream) were simultaneously sampled measuring physical and biogeochemical parameters. The prominent effect of tidal cycle was observed on the variability in physical and biogeochemical-biological parameters. The study discerned prominent evidence of riverine silicate source at both downstream as well as upstream and depletion in silicate concentration during high tide in the downstream. In addition, accumulation of higher level of nitrate in downstream with freshwater inflow during low tide have been observed. The dissolved oxygen concentration oscillated with higher magnitude during high tide. The low tide in the upstream was observed with decline in nitrate concentration. Phytoplankton abundance discerned higher cell count at upstream in comparison to downstream during both high and low tide. Diatom evolved as the dominant phytoplankton flora irrespective of tides and salinity regimes. Apart from microscopy, chromatographic evidence of fucoxanthin and zeaxanthin pigments in the estuarine waters revealed predominance of diatoms and cyanobacteria, respectively. Concentration of facultative bacteria, Escherichia coli was observed in higher number during low tide with increased fresh water inflow. The outcome of this study will be used in setting observatories for now-casting and subsequently model based forecasting of water quality. |