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N2 production rates limited by nitrite availability in the Bay of Bengal oxygen minimum zone

DRS at CSIR-National Institute of Oceanography

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Title N2 production rates limited by nitrite availability in the Bay of Bengal oxygen minimum zone
 
Creator Bristow, L.A.
Callbeck, C.M.
Larsen, M.
Altabet, M.A.
Dekaezemacker, J.
Forth, M.
Gauns, M.
Glud, R.N.
Kuypers, M.M.M.
Lavik, G.
Milucka, J.
Naqvi, S.W.A.
Pratihary, A.K.
Revsbech, N.P.
Thamdrup, B.
Treusch, A.H.
Canfield, D.E.
 
Subject Chemistry and biogeochemistry
Chemistry and biogeochemistry
Microbiology
 
Description A third or more of the fixed nitrogen lost from the oceans as N2 is removed by anaerobic microbial processes in open ocean oxygen minimum zones. These zones have expanded over the past decades, and further anthropogenically induced expansion could accelerate nitrogen loss. However, in the Bay of Bengal there has been no indication of nitrogen loss, although oxygen levels are below the detection level of conventional methods (1 to 2 ìM). Here we quantify the abundance of microbial genes associated with N2 production, measure nitrogen transformations in incubations of sampled seawater with isotopically labelled nitrogen compounds and analyse geochemical signatures of these processes in the water column. We find that the Bay of Bengal supports denitrifier and anammox microbial populations, mediating low, but significant N loss. Yet, unlike other oxygen minimum zones, our measurements using a highly sensitive oxygen sensor demonstrate that the Bay of Bengal has persistent concentrations of oxygen in the 10 to 200 nM range. We propose that this oxygen supports nitrite oxidation, thereby restricting the nitrite available for anammox or denitrification. If these traces of oxygen were removed, nitrogen loss in the Bay of Bengal oxygen minimum zone waters could accelerate to global significance
 
Date 2017-03-01T09:07:11Z
2017-03-01T09:07:11Z
2017
 
Type Journal Article
 
Identifier Nature Geoscience, vol.10; 2017; 24-29
http://drs.nio.org/drs/handle/2264/5082
 
Language en
 
Rights Copyright [2017]. All efforts have been made to respect the copyright to the best of our knowledge. Inadvertent omissions, if brought to our notice, stand for correction and withdrawal of document from this repository.
 
Publisher Macmillan Publishers Limited