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Record Details

Record 53 of 52539
Physical processes affecting availability of dissolved silicate for diatom production in the Arabian Sea
External Online Source: doi:10.1029/94JC01449
Author and Affiliation:
Young, David K.(NASA Stennis Space Center, Stennis Space Center, MS, United States)
Kindle, John C.(NASA Stennis Space Center, Stennis Space Center, MS, United States)
Abstract: A passive tracer to represent dissolved silicate concentrations, with biologically realistic uptake kinetics, is successfully incorporated into a three-dimensional, eddy-resolving, ocean circulation model of the Indian Ocean. Hypotheses are tested to evaluate physical processes which potentially affect the availability of silicate for diatom production in the Arabian Sea. An alternative mechanism is offered to the idea that open ocean upwelling is primarily responsible for the high, vertical nutrient flux and consequent large-scale phytoplankton bloom in the northwestern Arabian Sea during the southwest monsoon. Model results show that dissolved silicate in surface waters available for uptake by diatoms is primarily influenced by the intensity of nearshore upwelling from soutwest monsoonal wind forcing and by the offshore advective transport of surface waters. The upwelling, which in the model occurs within 200 +/- 50 km of the coast, appears to be a result of a combination of coastal upwelling, Elkman pumping, and divergence of the coastal flow as it turns offshore. Localized intensifications of silicate concentrations appear to be hydrodynamically driven and geographically correlated to coastal topographic features. The absence of diatoms in sediments of the eastern Arabian Basin is consistent with modeled distributional patterns of dissolved silicate resulting from limited westward advection of upwelled coastal waters from the western continental margin of India and rapid uptake of available silicate by diatoms. Concentrations of modeled silicate become sufficiently low to become unavailable for diatom production in the eastern Arabian Sea, a region between 61 deg E and 70 deg E at 8 deg N on the south, with the east and west boundaries converging on the north at approximately 67 deg E, 20 deg N.
Publication Date: Nov 15, 1994
Document ID:
19950034751
(Acquired Dec 28, 1995)
Accession Number: 95A66350
Subject Category: OCEANOGRAPHY
Document Type: Journal Article
Publication Information: Journal of Geophysical Research (ISSN 0148-0227); 99; C11; p. 22,619-22,632
Publisher Information: United States
Organization Source: NASA Stennis Space Center; Stennis Space Center, MS, United States
Description: 14p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: ALGAE; ARABIAN SEA; DISSOLVING; GROWTH; INDIAN OCEAN; KINETICS; OCEAN CURRENTS; OCEAN MODELS; SILICATES; SOLUTIONS; ADVECTION; COASTAL WATER; CONCENTRATION (COMPOSITION); MARINE BIOLOGY; OCEANOGRAPHY; PLANKTON; SEDIMENTS; SURFACE WATER; TOPOGRAPHY; UPWELLING WATER
Imprint And Other Notes: Journal of Geophysical Research vol. 99, no. C11 p. 22,619-22,632 November 15, 1994
Miscellaneous Notes: Research sponsored by ONR
Availability Source: Other Sources
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