HR: 0800h
AN: PP51C-1348    [Abstracts]
TI: Seasonal Sea Surface Temperature and Salinity Changes Over Last 22 kyr in the Western Arabian Sea
AU: * Naidu, P D
EM: divakar@darya.nio.org
AF: National Institute of Oceanography, Dona Paula, Panaji, Goa 403 004 India
AB: The variation of oxygen isotopic ratios between individual shells of planktic foraminifera of a given species and size may provide a novel out look on paleoceanography and foram ecology. In this context, the oxygen isotope analyses of individual Globigerinoides sacculifer were carried out from the Ocean Drilling Program Site 723A in the western Arabian Sea to unravel the seasonal changes for last 22 kyr. Analyses of single shells of G.sacculifer show ranges of 0.54 to 2.0 per mil in $\delta$$^{18}$O at various levels covering a time span of last 22 kyr. Maximum inter-shell $\delta$$^{18}$O variability and high standard deviation is noticed from 22 to 10 kyr, where as from 10 kyr onwards the inter shell $\delta$$^{18}$O variability decreased. The individual contribution of sea surface temperature (SST) and sea surface salinity (SSS) on the inter shell $\delta$$^{18}$O values of G. sacculifer were quantified. Seasonal SST ranges from 0.1 to 2.6 degree centigrade with maximum seasonal SST change during last glacial period and minimum seasonal SST change from 12 to 0.5 kyr. Similarly, greater SSS changes are documented during the last glacial period than in Holocene. The higher seasonal SST and SSS changes were caused due to more westerly winds during the last glacial period. On the other hand, lower seasonal SST and SSS changes during the Holocene were driven by less westerly winds. The seasonal SST and SSS data suggest that the change over phase from the strong westerly winds to less westerly winds took place between 12 to 10 kyr in the western Arabian Sea.
DE: 3030 Micropaleontology
DE: 1724 Ocean sciences
DE: 1040 Isotopic composition/chemistry
DE: 0315 Biosphere/atmosphere interactions
DE: 0400 Biogeosciences
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2004 AGU Fall Meeting