Coupling of thermocline depth and strength of the Indian, summer monsoon during deglaciation

  • Sushant S NaikEmail author
  • P Divakar Naidu


We investigated the variations in thermocline depth using the difference in \(\delta ^{18}\hbox {Oc}\) values between the two species of planktonic foraminifera, surface dwelling Globigerinoides ruber (s.s.) and thermocline dwelling Neogloboqudrina dutertrei, covering a time span of 9–23 kyr from the sediment core SK218/1 from the western Bay of Bengal (BoB). Here we show that during the strong phase of the Indian summer monsoon (12–9 kyr), a strong stratification leads to a shallow mixed layer and thermocline depth in the BoB as evident from higher \(\Delta \delta ^{18}\hbox {O}\) between the mixed layer and thermocline dwelling planktonic foraminifera species. Thus, a strong coupling between the Indian summer monsoon and thermocline depth in the BoB prevailed at a millennial time scale.


Monsoon the Bay of Bengal thermocline foraminifera salinity isotopes 



We thank the director, NIO, for his encouragement and support. Anita Garg was responsible for the IRMS measurements. Jayu Narvekar assisted with the figures. The NIO contribution number is No. 6306.


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© Indian Academy of Sciences 2019

Authors and Affiliations

  1. 1.CSIR–National Institute of OceanographyDona PaulaIndia

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