Ecological Studies in the Coastal Waters of Kalpakkam, East Coast of India, Bay of Bengal

Abstract Environmental studies such as coastal hydrography, biodiversity, nutrient dynamics, and thermal ecology have been carried out for the last several years at Kalpakkam, which harbors several nuclear facilities. The objective is to create baseline data as well as to assess the operational impact of the above facilities on environmental variables. The coastal waters are significantly influenced by monsoonal rainfall as well as by the adjoining backwater discharge, which gets anthropogenic inputs from various sources. The frequency of the appearance of bloom at this coast has increased, adversely affecting the coastal water quality and biological community. The phytoplankton density has increased during the posttsunami period as compared to the pretsunami period. Nitrogenous nutrients were found to limit the phytoplankton population during late summer and premonsoon periods. Mussels and barnacles constituted about 60%–70% of the total biofouling organisms at this location; barnacles settled throughout the year. Among the major groups of zooplankton, only bivalves established a successful relationship between larval abundance and adult settlement. Presence of about 300 species of marine fishes were recorded out of which 53 were new records and it also included a species new to fishery science. Habitat diversity and niche specialization analyses show 45.51% of the species are reef-associated, an indication of the unpolluted characteristics of these coastal waters. The results of recent thermal pollution studies revealed that a very small area in the discharge location is highly impacted. A recent survey of the Bay of Bengal area revealed the presence of a minimum oxygen zone (MOZ) at shallow depth (