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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 ...

Nitrogen cycling in the suboxic waters of the Arabian Sea

Devol, A.H.; Naqvi, S.W.A.; Codispoti, L.A. (Springer, 2006)

Arabian Sea contains one of the world's three large oxygen deficient zones (ODZ). Within the ODZ oxygen concentration is vanishingly small between about 200 and 800 m depth and in this depth interval denitrifications is ...

Organic carbon, and not copper, controls denitrification in oxygen minimum zones of the ocean

Ward, B.B.; Tuit, C.B.; Jayakumar, A.; Rich, J.J.; Moffett, J.; Naqvi, S.W.A. (Elsevier, 2008)

Incubation experiments under trace metal clean conditions and ambient oxygen concentrations were used to investigate the response of microbial assemblages in oxygen minimum zones (OMZs) to additions of organic carbon and ...

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 ...

The nitrogen cycle in the Arabian Sea

Bange, H.W.; Naqvi, S.W.A.; Codispoti, L.A. (Elsevier, 2005)

Despite their importance for the global oceanic nitrogen (N) cycle, estimates of N fluxes in the Arabian Sea remain in considerable uncertainty. In this report, we summarize current knowledge of important processes, including ...

The oceanic fixed nitrogen and nitrous oxide budgets: Moving targets as we enter the anthropocene?

Codispoti, L.A.; Brandes, J.A.; Christensen, J.P.; Devol, A.H.; Naqvi, S.W.A.; Paerl, H.W.; Yoshinari, T. (Institut de Ciencies del Mar de Barcelona, 2001)

New data forced to raise previous estimates of oceanic denitrification. The revised estimate of approx. 450 Tg N yr sup(-1) (Tg = 10 sup(12) g) produces an oceanic fixed N budget with a large deficit (approx. 200 Tg N yr ...

Is delta sup(15)N of sedimentary organic matter a good proxy for paleodenitrification in coastal waters of the eastern Arabian Sea?

Agnihotri, R.; Naqvi, S.W.A.; Kurian, S.; Altabet, M.A.; Bratton, J.F. (American Geophysical Union, 2009)

Recently published sedimentary records of delta sup(15)N from several coastal areas affected by both natural and anthropogenically produced shallow hypoxia with the objective of testing this as a proxy for denitrification ...

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 ...

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 ...