Record Details

Inorganic nitrogen and nitrate reduction in the Arabian Sea

DRS at CSIR-National Institute of Oceanography

View Archive Info
 
 
Field Value
 
Title Inorganic nitrogen and nitrate reduction in the Arabian Sea
 
Creator Naqvi, S.W.A.
Qasim, S.Z.
 
Subject Chemistry and Biogeochemistry
advection
reduction
nitrates
nitrogen
ISW, Arabian Sea
 
Description Concentration of inorganic nitrogen compounds within the euphotic zone is very low and it increases sharply in the thermocline layer. A steady decrease in the NO sub(3)-N occurs from south to north at intermediate depths. This is associated with nitrate minima in Northern Arabian Sea. Two maxima in NO sub(2)-N are observed in northern region. The shallow (primary) nitrite maximum with low nitrite occurs in surface layer near thermocline in conjunction with a relatively high dissolved oxygen. The intermediate (secondary) maximum is invariably associated with very low oxygen ( 0.1 ml.l/1). It is quite pronounced with nitrite reaching as high as 7 mu g-at.l/1. The secondary maximum is not observed south of 12 N lat. Nither the nitrate minima nor the secondary nitrite maximum seem to be associated with Persian Gulf water. It is suggested that these originate as a result of biological reduction of nitrate (denitrification) due to the prevailing reducing conditions associated with a pronounced depletion of dissolved oxygen below the thermocline. The nitrate deficits have been calculated using the relationships of the apparent oxygen utilization (AOU) with NO sub(3)-N and PO sub(4)-P. Results indicate a steady northward increase in nitrate deficits and in the depth range where denitrification occurs. Maximum values reaching up to 16.5 mu-at.l/1 are found around 20 degrees N lat. denitrification in Arabian Sea may possibly extend up to 11 or 12 degrees N lat.
 
Date 1995-05-14T10:00:57Z
2017-09-29T13:48:36Z
1995-05-14T10:00:57Z
2017-09-29T13:48:36Z
1983
 
Type Journal Article
 
Identifier Indian Journal of Marine Sciences, vol.12; 1983; 21-26
0379-5136
http://drs.nio.org/drs/handle/2264/6527
 
Language en
 
Relation Indian J Mar Sci
SCI
 
Publisher CSIR-NISCAIR