On the Correspondence between Stable Carbon Isotopes in Planktic Foraminiferal Species Globigerina bulloides and the Nutrients along a North-South Transect in South-Western Indian Ocean

Abstract

During the pilot expedition to the Southern Indian Ocean onboard ORV Sagar Kanya a total of twenty one surface sediment samples were collected along a north-south transect between 9.50 N to 55.010 S latitude and 73.560 E and 44.860 E longitudes. These samples were collected to study the response of carbon isotope (δ13C values) fractionation in calcareous shells of planktic foraminiferal species Globigerina bulloides towards the nutrient contents of the ambient sea waters along a northsouth transect in the south-western Indian Ocean. It may be inferred that isotopic values (δ13C) in general increase as the nutrient content of ambient water masses decreases in the regions south of 300 S latitude. On the other hand δ13C values are relatively low in the region north of 30o S having higher nutrients in the ambient waters. The results of present study demonstrate the potential of foraminiferal δ13C values to trace the signature of paleo-nutrients changes in this region. The inferences drawn here further necessitates to take up similar studies along many transect in and around study area to arrive at a comprehensive picture.