Poll Res. 43 (1–2) : 147-163 (2024) Copyright © EM International ISSN 0257–8050 IMPACT OF THERMAL DISCHARGE FROM A JAIGAD COASTAL POWER PLANT ON PHYTOPLANKTON A.S. TEKADE, G.N. KULKARNI AND S.T. INDULKAR College of Fishery Science, Department of Hydrograph, Ratnagiri, India (Received 21 November, 2023; Accepted 2 January, 2024) ABSTRACT The impact of thermal effluents from Jaigad coastal power plant located at the Jaigad coast, which is a major fishing village of Ratnagiri district (Maharashtra) along the central Konkan coast of India. Impact of thermal effluent on phytoplankton was studied by field observations. Monthly boat cruises (for 9 months) were carried out to study the effects of temperature on phytoplankton. Phytoplankton and chlorophyll a decreased during the transit of water, while at mixing point the chlorophyll a values recovered significantly. It is concluded that the effect of thermal discharge from the power plant on phytoplankton in the receiving water body is quite localized and phytoplankton distribution and abundance in the coastal waters per se are not affected. KEY WORDS : Thermal effluent, Phytoplankton, Chlorophyll a. INTRODUCTION One of the main uses of water in the power industry is to cool the power producing equipment. Water used for this purpose does cool the equipment, but at the same time, this results in heating up of the cooling water. Water used for power plant cooling is chemically altered for the purposes of extending the useful life of equipment and also to ensure efficient operation (Selvin et al. 2010). The discharged warm water from the outfall moves into the sea depending on predominant current features and mixing process. Therefore, it is necessary to study the marine impact of thermal discharge. Since once- through cooling system is the most economical way of condensing the exhaust steam from turbines, there is an increasing tendency for new nuclear and fossil fuel power plants to be located in coastal areas, so as to make use of the availability of the abundant seawater for condenser cooling (Winter and Conner, 1978). Planktonic organisms are drawn along with the cooling water into the plant cooling circuit, where they are subjected to various physical and chemical stress factors. Moreover, organisms in the receiving water body may also be entrained into the effluent plume, even if they do not pass through the plant cooling circuit. Temperature is one of the most important environmental variables, which affects the survival, growth and reproduction of aquatic organisms (Kinne, 1970; Langford, 1990). An increase in temperature of seawater results in an increase in the metabolic rate of the organisms and a reduction of its dissolved oxygen concentration. Phytoplankton’s are a very important constituent of the coastal food chain and, therefore, qualitative and quantitative changes in the phytoplankton population in the receiving water body may have significant implications for the coastal ecosystem. The present study was undertaken in the vicinity of the Jaigad Power Station, Ratnagiri, Maharashtra which uses the coastal waters of the as a heat sink. It was hypothesized that the continuous discharge of condenser effluents may have an impact on the ecology of the coastal marine environment in the vicinity of the plant and a study was organized to understand the influence of the discharge on the phytoplankton population near the discharge zone. Boat cruises were carried out to measure phytoplankton standing crop in the coastal waters. MATERIALS AND METHODS The present investigation was carried out along the cost of Jaigad (District Ratnagiri) Maharashtra. DOI No.: http://doi.org/10.53550/PR.2024.v43i01-02.027