Bhushan, Ravi and Dutta, Koushik and Agnihotri, Rajesh and Rengarajan, R and Singh, Satinder Pal (2014) DECADAL VARIATIONS IN OCEANIC PROPERTIES OF THE ARABIAN SEA WATER COLUMN SINCE GEOSECS. Radiocarbon, 51 (1). pp. 313-325. ISSN 0033-8222

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Abstract

This article reports temporal changes in the measured oceanic geochemical properties of the Arabian Sea and the equatorial Indian Ocean by reoccupying six stations investigated during the GEOSECS expedition in 1977 and 1978. Observed differences are interpreted in terms of plausible changes in the environment and climate that have occurred in response to natural or anthropogenic processes. The depth profiles of major parameters such as dissolved oxygen, Sigma CO2, major nutrients (silicates, nitrates, and phosphates), and radiocarbon in dissolved inorganic carbon were measured during the cruises between 1994 and 1998 along with temperature and salinity. Most stations in the Arabian Sea show an increase in salinity by 0.2 to 0.3 salinity units in the top 400 m, whereas one station in the equatorial Indian Ocean showed a decrease in salinity by 0.1 units, indicating a likely change in the evaporation-precipitation(E-P) balance. The SCO2 increased by an average of 8 mu M within the top 1200 m of the Arabian Sea. The depth profiles of nitrates and dissolved oxygen for the central Arabian Sea stations show significant variations, while only marginal changes are seen for silicates and phosphates relative to the GEOSECS data. The decrease triangle C-14 of surface waters is due to the steady decrease in atmospheric 14C concentration since GEOSECS, and triangle C-14 increase in subsurface waters is attributed to the downward vertical diffusion of bomb 14C interpreted in terms of atmosphere to ocean transfer and lateral advection of water masses.

Item Type:	Article
Additional Information:	Copyright for this article belongs to M/S University of Arizona.
Subjects:	Geochemistry/ Geophysics
Divisions:	UNSPECIFIED
Depositing User:	Dr. Rajpal Walke
Date Deposited:	18 Sep 2015 11:14
Last Modified:	18 Sep 2015 11:14
URI:	http://npl.csircentral.net/id/eprint/1225

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