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Nitrate reducing activity pervades surface waters during upwelling.

DRS at CSIR-National Institute of Oceanography

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Title Nitrate reducing activity pervades surface waters during upwelling.
 
Creator Fernandes, S.O.
Halarnekar, R.
Malik, A.
Vijayan, V.
Varik, S.
RituKumari
Jineesh V.K.
Gauns, M.U.
Nair, S.
LokaBharathi, P.A.
 
Subject bacteria
coastal waters
nitrification
nitrates
nutrients (mineral)
upwelling
 
Description Nitrate reducing activity (NRA) is known to be mediated by microaerophilic to anaerobic bacteria and generally occurs in the sub-surface waters. However, we hypothesize that NRA could become prominent in the surface waters during upwelling. Hence, we examined nitrification and nitrate reduction along with hydrographic and environmental parameters off Trivandrum and Kochi, south-west-India in June 2010. Shoaling isolines of temperature, density, and nutrients revealed the onset of upwelling off Trivandrum. Shoaling of these signatures was absent in the northern transect off Kochi. The degree of nutrient consumption (DNC) was low emphasizing the presence of newly upwelled water off Trivandrum. A significant increase in NRA (df = 1, p b 0.05) was observed off Trivandrum than at Kochi. Moreover, as hypothesized, NRA at Trivandrum was pronounced at the surface with a maximum rate of 0.85 (±0.02) ~k mol L1 h-1 nearshore which was ~29× higher than that at Kochi. Further, an inverse relationship between NRA and NO-3 concentration (n = 34, r = -0.415, p b 0.01) suggested transformation of the upwelled nutrient. Nitrification/NRA was ~10× lower at 0.28 off Trivandrum indicating a discernible shift towards reduction. Such contribution from bacterial activity could be a response towards restoration of homeostasis.
 
Date 2014-06-11T11:25:24Z
2014-06-11T11:25:24Z
2014
 
Type Journal Article
 
Identifier Journal of Marine Systems, vol.137; 2014; 35-46.
no
http://drs.nio.org/drs/handle/2264/4540
 
Language en
 
Relation Bioorg_Med_Chem_Lett_24_2863.jpg
 
Rights An edited version of this paper was published by Elsevier. Copyright [2014] Elsevier
 
Publisher Elsevier