Skip to main content
Log in

Last 10000 years Variation in the Intensity of OMZ-Core Reconstructed from Sediment of the Eastern Arabian Sea

  • Research Articles
  • Published:
Journal of the Geological Society of India

Abstract

The Arabian Sea Oxygen Minimum Zone (OMZ) is one of the most intense of the world ocean OMZs witnessing denitrification, hence, has implications to global climate. In order to understand the Holocene variations in the OMZ of this region, a sediment core (BP3-GCR3) from a water depth of 500 m was retrieved, which is presently swept by nearly anoxic waters of the core of the OMZ. The sedimentary oxide-bound Mn, a reliable redox proxy, exhibits a gradual decrease from ∼14 ppm during the early-Holocene to ∼8 ppm during the late-Holocene, suggesting a relatively less intense OMZ during the former period. The concentration of a suite of other redox-sensitive elements (Fe, Co and Ce) associated with the dispersed sedimentary oxide particulates also show a gradual and coherent decrease through the Holocene suggesting reduction of dissolved oxygen (DO) in the core of the OMZ towards the modern times. This intensification of OMZ seems to be a result of increased export production coupled with decreasing ventilation of thermocline waters through the Holocene. A one-time positive shift is observed at ∼5.5 ka BP in the organic carbon content (OC) from ∼2 % to ∼10 % in core-top. This shift in OC content is also marked by rapid decrease of CaCO3 by ∼20 %, suggesting enhanced carbonate dissolution due to increased anoxia in the OMZ core caused by increased export production in the late Holocene.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others

References

Download references

Acknowledgements

We thank Director, CSIR-NIO for permission to publish this work. GJ acknowledges the financial support by the Department of Science and Technology, DST-INSPIRE Fellowship (IF-120826). The sediment core was collected with the assistance of crew on board RV Boris Petrov chartered by the MoES for Cobalt-Crust Exploration program. This is NIO contribution No. 6609.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Sushant S. Naik.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Joshi, G.P., Naik, S.S. & Banakar, V.K. Last 10000 years Variation in the Intensity of OMZ-Core Reconstructed from Sediment of the Eastern Arabian Sea. J Geol Soc India 97, 243–248 (2021). https://doi.org/10.1007/s12594-021-1673-7

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s12594-021-1673-7

Navigation