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@u234@@Th scavenging and particle export fluxes from the upper 100 m of the Arabian Sea

DRS at CSIR-National Institute of Oceanography

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Title @u234@@Th scavenging and particle export fluxes from the upper 100 m of the Arabian Sea
 
Creator Sarin, M.M.
Rengarajan, R.
Ramaswamy, V.
 
Subject Chemistry and Biogeochemistry
Geology and Geophysics
thorium isotopes
spatial variations
temporal variations
primary production
sediment traps
carbon
ISW, Arabian Sea
 
Description We have determined the particle scavenging rates, export fluxes of @u234@@Th and settling particles from the upper 100 m of the Arabian Sea as a part of the JGOFS (India) Programme. The spatial and temporal measurements made in the open ocean profiles reveal close similarities in the dissolved @u234@@Th: @u238@@U disequilibria, suggesting that the rates of particle-associated scavenging processes are generally uniform in the central Arabian Sea. The observed disequilibrium integrated for the upper 100 m yields a mean scavenging residence time of ~k30 days and a removal rate of ~k 3400 dpm m@u-2@@ d@u-1@@ for @u234@@Th, from dissolved to particulate phases. The deficiency of total @u234@@Th (dissolved + particulate) relative to @u238@@U allows us to compute the vertical export flux of particulate @u234@@Th. The flux data for the upper 100 m show spatial variations with enhanced export fluxes centered around 22~'N 67~'E, a region characterized by higher rates of column primary productivity. Using the @u234@@Th export fluxes and the measured specific activity of @u234@@Th in the sediment traps, we have computed th eparticle and carbon fluxes at 100 m. These results reveal that the particle fluxes determined from sediment traps are systematically low and the estimated C export fluxes are grossly out of proportion with the column primary production.
 
Date 1997-04-08T10:09:39Z
2017-09-30T03:04:24Z
1997-04-08T10:09:39Z
2017-09-30T03:04:24Z
1996
 
Type Journal Article
 
Identifier Current Science, vol.71(11); 1996; 888-893
0011-3891
http://drs.nio.org/drs/handle/2264/7524
 
Language en
 
Relation Curr Sci India
SCI
 
Publisher Current Science Association