Size variations of planktonic foraminiferal population in the Indian Ocean sector of Southern Ocean

Abstract

221-226Twenty five surface sediment samples (comprising Peterson Grab, Piston, Gravity and Spade core top samples) were collected along a north-south transect (between 9.69º N and 55.01º S latitude and 80º E and 40º E longitude). On the basis of overall size, the total planktonic population has been divided into two groups (> 120 μm sized population and <120 μm sized population). The results show an apparent interrelationship between shell size and variations in hydrographic conditions such as food availability/nutrition (phosphate) of ambient water masses. It is apparent that nutrients play a significant role in determining the size of the foraminiferal population and an increase in the nutrient supply is conducive for the growth of the planktonic population