Frequency Distribution of Foraminifera Off Trivandrum, West Coast of India

Abstract

Fifty two species belonging to 31 genera of recent foraminifera have been identified from sediment samples collected from the inshore waters. Based on relative abundance of species, it is observed that along the coast, the nearshore region up to 5 m depth is dominated by Asterorotalia dentata and others in lesser abundance being Elphidium advenum and Amphistegina radiata, whereas in the offshore region (10 to 20 m water depth), there is a change in the species composition of the fauna, the most abundant form is Ammonia beccarii (Linne) tepida and other species include Operculina ammonoides, Nonion asterizans and Hanzawaia concentrica. Comparison of the fauna of the Trivandrum area with that of Cochin Region, Kerala, India shows 14 common species and due to prevailing marine conditions, no brackish-water species of the indigenous fauna reported from Cochin region, are encountered from the coastal waters of Trivandrum. Also, faunal trends in relation to pollution caused by the effluent discharge from an industrial plant situated along the coast, are discussed with particular emphasis on pH and species diversity index.