Downcore Variation Relative Abundance and Diversity of Benthic Foraminifera of a Sedimentary Core from the Lower Continental Slope of Central Western Bay of Bengal

Abstract

ABSTRACT newline newlineBenthic foraminifera are single-celled microorganisms found ubiquitously in newlineall the marine habitats and possess well-preserved fossil records ranging from newlineCambrian to Recent. Benthic foraminifera has been used widely to typify water newlinedepths of modern marine environments and to derive paleo-bathymetry which is newlineuseful in understanding eustatic sea-level changes, paleo-ecology, paleo-productivity, newlinepaleo-climate, paleo-oceanography etc. newline newlineThe aim/purpose of this study is to document the occurrence, abundance, newlinedowncore (vertical) variations, and diversity of benthic foraminiferal species newlineincluding P/B, P/R ratios etc. of a core sample (B3) measuring 4.9 m collected from newlinethe Lower Continental slope of Central Western Bay of Bengal.. newline A total of 163 benthic foraminiferal species are identified of which 7 are Very newlineAbundant, 15 are Abundant, 38 common, and 103 are considered as rare. In addition newlineto these 9 Planktonic Foraminifera (up to generic level) and absolute no s of newlineRadiolarians up to order level i.e. Spumellarians and Nassellarians, and absolute no s newlineof Ostacoda are also identified and were present only in a few sub-samples with one newlineindividual each.It is observed that the abundance of Benthic foraminifera is relatively newlinemore in the top segment and moderate in the middle segment compared to the bottom newlinesegment which reflects the environmental variability i.e. paleo productivity etc during newlinethe deposition of these sediments. Among the seven very abundant species relative newlineabundance and frequency distribution of Bulimina aculeata and Uvigerina hispidocostata newline newlineare very high followed by others. This suggests environmental variation i.e. newlineproductivity, bottom water temperature, oxygen content, food/ organic matter/ newlinenutrition, climate, riverine input/ flux, etc. during the deposition of these sediments of newlinethe B3 core in the Late Quaternary period (expected?) in the Central Western Bay of newlineBengal. Benthic foraminifera are very sensitive to ambient conditions and hence are newlinemore suitable to reconstruct the paleo en