Bay of Bengal nutrient-rich benthic layer

Arnold L. Gordon, Claudia F. Giulivi, Taro Takahashi, Stewart Sutherland, John Morrison, Donald Olson

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Abstract

A nutrient- and carbon-rich, oxygen-poor benthic layer is observed in the lower 100m of the central and western Bay of Bengal, at depths between 3400 to 4000 m. The observed ratios for the biogeochemical anomalies in the benthic layer water are similar to those observed for phytoplankton blooms in open oceans and hence suggest that the source of the high silica, phosphate, nitrate and carbon is likely to be due to decomposition of marine plankton deposited on the Ganges fan. While similar sediment types are expected to exist across a more extensive area of the Bay of Bengal, accumulation of nutrients only within a confined pool of bottom water is due to a greater degree of ventilation elsewhere. To the north of the nutrient-rich benthic pool, in shallower water, inflow of water from West Australian Basin minimizes anomalous benthic properties. To the south, in deeper water, ventilation by bottom water of the Central Indian Basin lifts the Bay of Bengal nutrient-rich benthic water off the sea floor. Thus the nutrient-rich benthic layer occupies zone between better ventilated regions. A counter-clockwise flow of bottom water is suggested for the Bay of Bengal, with nutrient-rich bottom water flowing westward south of Sri Lanka.

Original languageEnglish (US)
Pages (from-to)1411-1421
Number of pages11
JournalDeep-Sea Research Part II: Topical Studies in Oceanography
Volume49
Issue number7-8
DOIs
StatePublished - Apr 22 2002

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ASJC Scopus subject areas

  • Oceanography

Cite this

Gordon, A. L., Giulivi, C. F., Takahashi, T., Sutherland, S., Morrison, J., & Olson, D. (2002). Bay of Bengal nutrient-rich benthic layer. Deep-Sea Research Part II: Topical Studies in Oceanography, 49(7-8), 1411-1421. https://doi.org/10.1016/S0967-0645(01)00161-8