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Summer monsoon onset-induced changes of autotrophic pico- and nanoplankton in the largest monsoonal estuary along the west coast of India

DRS at CSIR-National Institute of Oceanography

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Title Summer monsoon onset-induced changes of autotrophic pico- and nanoplankton in the largest monsoonal estuary along the west coast of India
 
Creator Mohan, A.P.
Jyothibabu, R.
Jagadeesan, L.
Lallu, K.R.
Karnan, C.
 
Subject AQUATIC COMMUNITIES
AQUATIC ECOLOGY, PRODUCTIVITY
POPULATION STUDIES
 
Description This study presents the response of autotrophic pico- and nanoplankton to southwest monsoon-associated hydrographical transformations in the Cochin backwaters (CBW), the largest monsoonal estuary along the west coast of India. By the onset of the southwest monsoon, the euhaline/mesohaline conditions in the downstream/upstream of CBW usually transform into oligohaline/limnohaline. The flow cytometer analysis revealed the dominance of picoeukaryotes>Synechococcus>nanoautotrophs, with Prochlorococcus either very low or entirely absent. Synechococcus abundance was high during the pre-southwest monsoon (106 L-1), which dwindled with heavy fresh water influx during the southwest monsoon (105 L-1). The drastic drop in salinity and faster flushing of the CBW during the southwest monsoon replaced the euhaline/mesohaline strain of Synechococcus with an oligohaline/limnohaline strain. Epifluorescence microscopy analyses showed that, among the two strains of Synechococcus, the phycoerythrin-rich (PE-rich) one was dominant in the mesohaline/euhaline conditions, whereas the phycocyanin-rich (PC-rich) strain dominated in oligohaline/limnohaline conditions. Although Synechococcus abundance diminished during the southwest monsoon, the total abundance of picoplankton community remained virtually unchanged in the upstream due to an increase in the abundance of picoeukaryotes. On the other hand, the autotrophic nanoplankton abundance increased from pre-monsoon levels of av. 3.8×106–av. 9.5×106 at the onset of the southwest monsoon. Utilizing suitable multivariate analyses, the study illustrated the differential response and niche preference of various smaller communities of autotrophs to the southwest monsoon-associated hydrographical ramifications in a large monsoonal estuary, which may be applicable to similar such estuaries situated along the Indian coastline
 
Date 2016-02-04T04:50:25Z
2016-02-04T04:50:25Z
2016
 
Type Journal Article
 
Identifier Environmental Monitoring and Assessment, vol.188; 2016; no.93 doi: 10.1007/s10661-016-5096-7
http://drs.nio.org/drs/handle/2264/4909
 
Language en
 
Rights An edited version of this paper was published by Springer. This paper is for R & D purpose and Copyright [2015] Springer
 
Publisher Springer