Oxygen Minimum Zone Contrasts Between the Arabian Sea and the Bay of Bengal Implied by Differences in Remineralization Depth

Muchamad Al Azhar, Zouhair Lachkar, Marina Lévy, Shafer Smith

Research output: Contribution to journalArticle


The combination of high primary productivity and weak ventilation in the Arabian Sea (AS) and Bay of Bengal (BoB) generates vast areas of depleted oxygen, known as oxygen minimum zones (OMZs). The AS OMZ is the world's thickest and hosts up to 40% of global denitrification. In contrast, the OMZ in the BoB is weaker and denitrification free. Using a series of model simulations, we show that the deeper remineralization depth (RD) in the BoB, potentially associated with organic matter aggregation with riverine mineral particles, contributes to weaken its OMZ. When the RD is set uniformly across both seas, the model fails to reproduce the observed contrast between the two OMZs, irrespective of the chosen RD. In contrast, when the RD is allowed to vary spatially, the contrasting distributions of oxygen and nitrate are correctly reproduced, and water column denitrification is simulated exclusively in the AS, in agreement with observations.

Original languageEnglish (US)
Pages (from-to)11,106-11,114
JournalGeophysical Research Letters
Issue number21
StatePublished - Nov 16 2017



  • biogeochemical cycles
  • denitrification
  • oxygen minimum zones
  • remineralization depth
  • the Arabian Sea
  • the Bay of Bengal

ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)

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