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dc.contributor.authorSarma, V.V.S.S.
dc.contributor.authorGupta, S.N.M.
dc.contributor.authorBabu, P.V.R.
dc.contributor.authorAcharyya, T.
dc.contributor.authorHarikrishnachari, N.
dc.contributor.authorVishnuvardhan, K.
dc.contributor.authorRao, N.S.
dc.contributor.authorReddy, N.P.C.
dc.contributor.authorSarma, V.V.
dc.contributor.authorSadhuram, Y.
dc.contributor.authorMurty, T.V.R.
dc.contributor.authorKumar, M.D.
dc.date.accessioned2009-11-27T14:26:26Z
dc.date.available2009-11-27T14:26:26Z
dc.date.issued2009
dc.identifier.citationEstuarine, Coastal and Shelf Science, vol.85(4); 515-524
dc.identifier.otherno
dc.identifier.urihttp://drs.nio.org/drs/handle/2264/3458
dc.description.abstractTo examine the influence of river discharge on plankton metabolic balance in a monsoon driven tropical estuary, daily variations in physico-chemical and nutrients characteristics were studied over a period of 15 months (September 2007 to November 2008) at a fixed location (Yanam) in the Godavari estuary, India. River discharge was at its peak during July to September with a sharp decrease in the middle of December and complete cessation thereafter. Significant amount of dissolved inorganic nitrogen (DIN, of 22-26 Mu mol l sup(-1)) and dissolved inorganic phosphate (DIP, of 3-4 mmol l sup(-1)) along with suspended materials (0.2-0.5 g l sup(-1)) were found at the study region during the peak discharge period. A net heterotrophy with low gross primary production (GPP) occurred during the peak discharge period. The Chlorophyll a (Chl a) varied between 4 and 18 mg m sup(-3) that reached maximum levels when river discharge and suspended loads decreased by >75% compared to that during peak period. High productivity was sustained for about one and half months during October to November when net community production (NCP) turned from net heterotrophy to autotrophy in the photic zone. Rapid decrease in nutrients (DIN and DIP by approx. 15 and 1.4 Mu mol l sup(-1), respectively) was observed during the peak Chl a period of two weeks. Chl a in the post monsoon (October–November) was negatively related to river discharge. Another peak in Chl a in January to February was associated with higher nutrient concentrations and high DIN:DIP ratios suggest possible external supply of nitrogen into the system. The mean photic zone productivity to respiration ratio (P:R) was 2.38 plus or minus 0.24 for the entire study period (September 2007-November 2008). Nevertheless, the ratio of GPP to the entire water column respiration was only 0.14 plus or minus 0.02 revealing that primary production was not enough to support water column heterotrophic activity. The excess carbon demand by the heterotrophs could be met from the allochthonous inputs of mainly terrestrial origin. Assuming that the entire phytoplankton produced organic material was utilized, the additional terrestrial organic carbon supported the total bacterial activity (97-99%) during peak discharge period and 40-75% during dry period. Therefore, large amount of terrestrial organic carbon is getting decomposed in the Godavari estuarine system
dc.language.isoen
dc.publisherElsevier
dc.rightsAn edited version of this paper was published by Elsevier. Copyright [2009] Elsevier
dc.subjectprimary production
dc.subjectriver discharge
dc.subjectbiogeochemistry
dc.subjectcommunity respiration
dc.titleInfluence of river discharge on plankton metabolic rates in the tropical monsoon driven Godavari estuary, India
dc.typeJournal Article


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