Strong Intensification of the Arabian Sea Oxygen Minimum Zone in Response to Arabian Gulf Warming

Research output: Contribution to journalArticle

Abstract

The highly saline, oxygen-saturated waters of the Arabian Gulf (hereafter the Gulf) sink to intermediate depths (200–300 m) when they enter the Arabian Sea, ventilating the World's thickest oxygen minimum zone (OMZ). Here, we investigate the impacts of a warming of the Gulf consistent with climate change projections on the intensity of this OMZ. Using a series of eddy-resolving model simulations, we show that the warming of the Gulf waters increases their buoyancy and hence limits their contribution to the ventilation of intermediate depths. This leads to an intensification of the OMZ and an increase in denitrification that depletes subsurface nitrate and limits deoxygenation at depth. The projected future concomitant increase of Gulf salinity only partially reduces the OMZ intensification. Our findings highlight the importance of the Arabian marginal seas for the biogeochemistry of the North Indian Ocean and stress the need for improving their representation in global climate models.

Original languageEnglish (US)
JournalGeophysical Research Letters
DOIs
StatePublished - Jan 1 2019

Fingerprint

Arabian Sea
gulfs
warming
oxygen
heating
biogeochemistry
deoxygenation
marginal sea
Indian Ocean
climate models
ventilation
climate change
salinity
sinks
buoyancy
water
nitrates
denitrification
global climate
climate modeling

Keywords

  • Arabian Gulf
  • Arabian Sea
  • climate change
  • marginal seas
  • oxygen minimum zones
  • Persian Gulf

ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)

Cite this

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abstract = "The highly saline, oxygen-saturated waters of the Arabian Gulf (hereafter the Gulf) sink to intermediate depths (200–300 m) when they enter the Arabian Sea, ventilating the World's thickest oxygen minimum zone (OMZ). Here, we investigate the impacts of a warming of the Gulf consistent with climate change projections on the intensity of this OMZ. Using a series of eddy-resolving model simulations, we show that the warming of the Gulf waters increases their buoyancy and hence limits their contribution to the ventilation of intermediate depths. This leads to an intensification of the OMZ and an increase in denitrification that depletes subsurface nitrate and limits deoxygenation at depth. The projected future concomitant increase of Gulf salinity only partially reduces the OMZ intensification. Our findings highlight the importance of the Arabian marginal seas for the biogeochemistry of the North Indian Ocean and stress the need for improving their representation in global climate models.",
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AU - Shafer-Smith, Kendall

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N2 - The highly saline, oxygen-saturated waters of the Arabian Gulf (hereafter the Gulf) sink to intermediate depths (200–300 m) when they enter the Arabian Sea, ventilating the World's thickest oxygen minimum zone (OMZ). Here, we investigate the impacts of a warming of the Gulf consistent with climate change projections on the intensity of this OMZ. Using a series of eddy-resolving model simulations, we show that the warming of the Gulf waters increases their buoyancy and hence limits their contribution to the ventilation of intermediate depths. This leads to an intensification of the OMZ and an increase in denitrification that depletes subsurface nitrate and limits deoxygenation at depth. The projected future concomitant increase of Gulf salinity only partially reduces the OMZ intensification. Our findings highlight the importance of the Arabian marginal seas for the biogeochemistry of the North Indian Ocean and stress the need for improving their representation in global climate models.

AB - The highly saline, oxygen-saturated waters of the Arabian Gulf (hereafter the Gulf) sink to intermediate depths (200–300 m) when they enter the Arabian Sea, ventilating the World's thickest oxygen minimum zone (OMZ). Here, we investigate the impacts of a warming of the Gulf consistent with climate change projections on the intensity of this OMZ. Using a series of eddy-resolving model simulations, we show that the warming of the Gulf waters increases their buoyancy and hence limits their contribution to the ventilation of intermediate depths. This leads to an intensification of the OMZ and an increase in denitrification that depletes subsurface nitrate and limits deoxygenation at depth. The projected future concomitant increase of Gulf salinity only partially reduces the OMZ intensification. Our findings highlight the importance of the Arabian marginal seas for the biogeochemistry of the North Indian Ocean and stress the need for improving their representation in global climate models.

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