Study of dissolve oxygen, salinity and temperature around western offshore- A case study around North Bombay of ONGC’s offshore Filed, Arabian Sea, India

Marine ecosystems cover approximately 71% of the Earth's surface and contain approximately 97% of the planet's water. Dissolve oxygen, which is a vital parameter in Ocean’s primary production, is having a sensitive integrating property reflecting physical and biogeochemical changes in the marine environment. The other parameters like temperature, though conservative, has a great impact upon biological productivity and salinity is important to understand the dynamics of water column. By analyzing the variation of dissolve oxygen, temperature and salinity, environmental status of that particular study area can be assessed. As a preventive measure to protect water bodies, Oil and Natural Gas Corporation Limited, India is regularly conducting Offshore Environment Monitoring around western continental shelf of Arabian Sea, where ONGC’s Platforms and Installations are located.
The paper includes the output of monitoring activities of ONGC around north Bombay considering these three parameters i.e. temperature, salinity and dissolved oxygen for assessing the environmental health of the study area. A trend analysis of the three parameters around North Bombay of ONGC’s offshore Filed (NA & NQ platform) has been done considering the monitoring data from the year 2017-18 to 2020-21 and their variation has been studied. It has been observed from the study that there is an increasing trend of dissolve oxygen and salinity for both platform (NA & NQ). It is observed that trend of temperature for NA platform is decreasing whereas around NQ it is increasing. The mean values of three parameters are comparable with reference mean values and the variations are insignificant.