Atypical delta sup(13) C signature in Globigerina bulloides at the ODP site 723A (Arabian Sea): Implications of environmental changes caused by upwelling

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dc.contributor.author Naidu, P.D.
dc.contributor.author Niitsuma, N.
dc.date.accessioned 2008-07-02T05:06:16Z
dc.date.available 2008-07-02T05:06:16Z
dc.date.issued 2004
dc.identifier.citation Marine Micropaleontology, Vol.53; 1-10p.
dc.identifier.uri http://drs.nio.org/drs/handle/2264/1147
dc.description.abstract Production of Globigerina bulloides generally increases during upwelling in the tropical ocean and, in particular, during southwest monsoon season in the Arabian Sea. We studied the delta sup(13) C signatures of Globigerina bulloides from Ocean Drilling Program (ODP) site 723A located in the intense upwelling area along the Oman Margin, Arabian Sea is studied. The delta sup(13) C signature of G. bulloides from the Oman Margin during the last 19 ka ranges from -2.65 ppt to -1.13 ppt. Strikingly, the delta sup(13) C values of G. bulloides are about 1 ppt lower than that of benthic foraminifera Uvigerina excellens at this site. Apparently, the vital effects induced carbon isotopic fractionation in G. bulloides results in abnormal delta sup(13) C values. During upwelling seasons, G. bulloides calcifies faster, perhaps because of high-nutrient availability. Faster calcification rates in this species require higher respiration, which involves more respired CO sub(2) enriched with sup(12)C accounting for nearly 10% of shell carbon. Therefore, the combination the foraminifera of faster calcification and involvement of respired CO sub(2) would induce more negative delta sup(13) C in G. bulloides compared to other foraminifera. Apart from vital effects, the environmental changes caused by the variations of upwelling intensity during Holocene and last glacial maximum also affected the down-core delta sup(13) C record of G. bulloides in the Arabian Sea. Significant ontogenic differences in both delta sup(18) O and delta (13) C occurred between large and small size classes of G. bulloides.
dc.language.iso en
dc.publisher Elsevier
dc.rights Copyright [2004]. It is tried to respect the rights of the copyright holders to the best of the knowledge. If it is brought to our notice that the rights are violated then the item would be withdrawn.
dc.subject upwelling
dc.subject carbon isotopes
dc.subject environmental impact
dc.subject foraminifera
dc.subject holocene
dc.subject oxygen isotopes
dc.subject radiocarbon dating
dc.subject circulation
dc.title Atypical delta sup(13) C signature in Globigerina bulloides at the ODP site 723A (Arabian Sea): Implications of environmental changes caused by upwelling
dc.type Journal Article


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