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dc.contributor.authorRakesh, M.
dc.contributor.authorMadhavirani, K.S.V.K.S.
dc.contributor.authorKumar, B.C.
dc.contributor.authorRaman, A.V.
dc.contributor.authorKalavati, C.
dc.contributor.authorRao, Y.P.
dc.contributor.authorStephen, R.
dc.contributor.authorRao, V.R.
dc.contributor.authorGupta, G.V.M.
dc.contributor.authorSubramanian, B.R.
dc.date.accessioned2015-10-27T10:37:40Z
dc.date.available2015-10-27T10:37:40Z
dc.date.issued2015
dc.identifier.citationRegional Studies in Marine Science, vol.1; 2015; 72-84
dc.identifier.urihttp://drs.nio.org/drs/handle/2264/4833
dc.description.abstractCoastal lagoons around the world have become increasingly vulnerable to eutrophication and often the impingement is severe with regard to plankton. In this study, we measured how environmental heterogeneity persuades mesozooplankton (MSP) community dynamics in a large tropical coastal lagoon wrought by human impingement, including the creation of a new mouth. Here, we hypothesised that trophic gradients and environmental redundancy resulting from the pooled effect of trophic and salinity–light gradients majorly influence MSP structure in one of Asia’s largest brackish water lagoons in India. Multivariate analysis of environmental variables (May 2004–September 2006; View the MathML source) and MSP examined (May 2004 to October 2005; View the MathML source) at monthly intervals revealed discrete hydrographical and MSP regimes. Beta diversity measures revealed ~50% community turn-over between assemblages. Residual analysis on salinity-corrected fractionated chlorophyll a and size-specific copepod functional groups revealed pico-nanoplankton (<20 View the MathML source) supporting spatial patterns of small omnivorous copepods lagoon wide (r<sup>2</sup>:0.487). A lower than expected MSP grazing pressure on phytoplankton, revealed through MSP:phytoplankton biomass ratio, however, suggested the importance of alternative food sources and foraging effects, the significance of which varied spatially. MSP–environmental interactions through gradient analysis techniques revealed unimodal functionality of MSP to contrasting horizontal explanatory gradients offered by salinity–water column transparency and nutrients–chlorophyll a. Variance partitioning revealed the importance of measured (environmental redundancy 28%; trophic gradient 32%, salinity–light gradient, 6%) and unmeasured (residual, 34%) explanatory variables contributing to the total variation in MSP within the lagoon. Overall, the superseding effects of eutrophicants on MSP dynamics coupled with cyanophycean dominance in the system suggest that this tropical lagoon is on the verge of transformation into a eutrophic/hypereutrophic system, wherein the ecological benefits achieved through the opening of a new mouth in the year 2000 appear short lived. Such changes could result in large-scale implications through trophic cascades, altering MSP dynamics and ecosystem functioning.
dc.language.isoen
dc.publisherElsevier
dc.rightsAn edited version of this paper was published by Elsevier. Copyright [2015] Elsevier
dc.subjectAQUATIC COMMUNITIES::Zooplankton
dc.subjectPOPULATION STUDIES::Population dynamics
dc.subjectAQUATIC ECOLOGY, PRODUCTIVITY::Environmental effects
dc.titleTrophic–salinity gradients and environmental redundancy resolve mesozooplankton dynamics in a large tropical coastal lagoon
dc.typeJournal Article


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