Distribution of Foraminifera and Ostracoda in the North Chennai Coast (Ennore to Thiruvanmiur), Tamil Nadu: Implications on Microenvironment

Abstract

A total of 34 species of foraminifera belongs to Order Foraminiferida and 14 Ostracoda species to Order Podocopida were recorded from sediment and water samples collected from intertidal zone of north Chennai coast. Ammonia beccarii is the dominant and most widely distributed species of the coast. Intertidal fauna of north Chennai coast is a mixed assemblage of species from shoal environment (0-15 fathoms). Presence of offshore species in this study could be ascribed to the action of bottom water currents and wave/tide action. Water samples were showing alkaline nature. Species diversity indicates that sand is the favourable substrate for the surviving and abundance of the recorded fauna. It is also found that few of the identified foraminiferal species showing predated and some species exhibit different color pattern on the tests. Light color of the test reveals that these species were deposited under normal oxygenated environment.