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Oxygen minimum zone of the open Arabian Sea: variability of oxygen and nitrite from daily to decadal timescales.

Banse, K.; Naqvi, S.W.A.; Narvekar, P.V.; Postel, J.R.; Jayakumar, D.A. (European Geosciences Union, 2014)

The oxygen minimum zone (OMZ) of the Arabian Sea is the thickest of the three oceanic OMZ. It is of global biogeochemical significance because of denitrification in the upper part leading to N<SUB>2</SUB> and N<SUB>2</SUB>O ...

Denitrifying bacterial community composition changes associated with stages of denitrification in oxygen minimum zones

Jayakumar, D.A.; O'Mullan, G.D.; Naqvi, S.W.A.; Ward, B.B. (Springer, 2009)

Denitrification in the ocean is a major sink for fixed nitrogen in the global N budget, but the process is geographically restricted to a few oceanic regions, including three oceanic oxygen minimum zones (OMZ) and hemipelagic ...

Seasonal oxygen deficiency over the western continental shelf of India

Naqvi, S.W.A.; Naik, H.; Jayakumar, D.A.; Shailaja, M.S.; Narvekar, P.V. (Springer, 2006)

The North Indian Ocean contains about two-third of the global continental-margin area affected by natural oxygen deficiency (O2 less than 0.2 mL L sup(-1)) in the water column. Also, the littoral countries of this ...

Denitrification rates and excess nitrogen gas concentrations in the Arabian Sea oxygen deficient zone

Devol, A.H.; Uhlenhopp, A.G.; Naqvi, S.W.A.; Brandes, J.A.; Jayakumar, D.A.; Naik, H.; Gaurin, S.; Codispoti, L.A.; Yoshinari, T. (Elsevier, 2006)

Rates of canonical, i.e. heterotrophic, water-column denitrification were measured by sup(15)N incubation techniques at a number of coastal and open ocean stations in the Arabian Sea. Measurements of N2 :Ar gas ratios were ...

Nitrogen and oxygen isotopic composition of N sub(2)O from suboxic waters of the eastern tropical North Pacific and the Arabian Sea - measurement by continuous-flow isotope-ratio monitoring

Yoshinari, T.; Altabet, M.A.; Naqvi, S.W.A.; Codispoti, L.; Jayakumar, D.A.; Kuhland, M.; Devol, A. (Elsevier, 1997)

Nitrous oxide (N sub(2)O) is a trace gas that is increasing in the atmosphere. It contributes to the greenhouse effect and influence the global ozone distribution. Recent reports suggest that regions such as the Arabian ...

Increased marine production of N sub(2)O due to intensifying anoxia on the Indian continental shelf

Naqvi, S.W.A.; Jayakumar, D.A.; Narvekar, P.V.; Naik, H.; Sarma, V.V.S.S.; DeSouza, W.; Joseph, S.; George, M.D. (Macmillan, 2000)

Eutrophication of surface waters and hypoxia in bottom waters has been increasing in many coastal areas, leading to very large depletions of marine life in the affected regions. These areas of high surface productivity and ...

Nitrogen isotopic studies in the suboxic Arabian Sea

Naqvi, S.W.A.; Yoshinari, T.; Brandes, J.A.; Devol, A.H.; Jayakumar, D.A.; Narvekar, P.V.; Altabet, M.A.; Codispoti, L.A. (Indian Academy of Sciences, Bangalore, India, 1998)

Measurements of sup(15)N/ sup(14)N in dissolved molecular nitrogen (N sub(2)), nitrate (NO sub(3) sup(-)) and nitrous oxide (N sub(2)O) and sup(18)O/ sup(16)O in N sub(2)O [expressed as delta sup(15)N and delta sup(18)O, ...

Diversity of nitrite reductase genes (nirS) in the denitrifying water column of the coastal Arabian Sea

Jayakumar, D.A.; Francis, C.A.; Naqvi, S.W.A.; Ward, B.B. (Inter-Research, 2004)

Denitrification often occurs in the water column, underlying zones of intense productivity and decomposition in upwelling regions. In the denitrifying zone off the southwest coast of India, high concentrations of nitrite ...

Isotopic composition of nitrate in the central Arabian Sea and eastern tropical North Pacific: A tracer for mixing and nitrogen cycles

Brandes, J.A.; Devol, A.H.; Yoshinari, T.; Jayakumar, D.A.; Naqvi, S.W.A. (American Society of Limnology and Oceanography, 1998)

The delta sup(15)N composition of nitrate and N sub(2) gas was measured in the eastern tropical North Pacific (ETNP) and central Arabian Sea (AS) suboxic regions. The delta sup(15)N of nitrate increased from 6 ppt at 2,500 ...

Hydrochemistry of the Bay of Bengal: Possible reasons for a different water-column cycling of carbon and nitrogen from the Arabian Sea

Rao, C.K.; Naqvi, S.W.A.; DileepKumar, M.; Varaprasad, S.J.D.; Jayakumar, D.A.; George, M.D.; Singbal, S.Y.S. (Elsevier, 1994)

A study on biogeochemical cycling in the western Bay of Bengal was undertaken during two seasons (pre-southwest monsoon and northeast monsoon of 1991). Relationships of the conservative tracers NO and PO with potential ...