Impact of thermal discharge from a tropical coastal power plant on phytoplankton

(1) The impact of thermal effluents from coastal power plant located on the east coast of India on phytoplankton was studied by field observations and laboratory experiments. (2) Monthly boat cruises (for 15 months) and laboratory experiments were carried out to study the effects of temperature and chlorine on phytoplankton. (3) Phytoplankton and chlorophyll a decreased during the transit of water from intake point to outfall, while at mixing point the chlorophyll values recovered significantly. (4) Laboratory experiments revealed that decrease in chlorophyll and productivity was largely due to chlorination than due to elevated temperature. (5) Combined temperature and chlorine treatment experiments on phytoplankton showed little synergistic effects. (6) 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.