Contrasting phytoplankton community structure and

Authors: Sudarsana Rao Pandi Rayaprolu Kiran Nittala S Sarma A S Srikanth V V S S Sarma M S Krishna D Bandyopadhyay V R Prasad T Acharyya K G Reddy

Publish Date: 2013/12/18

Volume: 64, Issue: 1, Pages: 89-101

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Abstract

Absorption spectra particulate pigments and hydrochemical constituents were measured in the western Bay of Bengal BoB during JulyAugust 2010 when influence of river discharge is at peak Chromophoric dissolved organic matter CDOM absorption coefficient aCDOM440 displayed a significant inverse linear relationship with salinity in the surface waters implying conservative mixing of marine and terrestrial end members The northern part of the study area is influenced by discharge from the river Ganga and a dominant terrestrial CDOM signal is seen The southern part receives discharge from peninsular rivers with corresponding signals of higher CDOM than the linear model would indicate and higher UVspecific absorption coefficient SUVA indicating more aged and humified DOM Lower contribution of CDOM to total nonwater absorption and higher phytoplankton biomass chlorophyll a absorption coefficient aph440 but lower chlorophyll a specific phytoplankton absorption coefficient a ph 440 characterize the northern part compared to the southern part Chlorophyll b had a distinct linear relationship with chlorophyll a in the latter The size index SI indicated dominance of microphytoplankton in the northern and nano and picophytoplankton in the southern parts Chlorophyll a is significantly related to a ph 440 by an inverse power model in the northern part but by an inverse linear model in the southern part Our study suggests that knowledge of the phytoplankton community structure is essential to improve chlorophyll a algorithm in the coastal Bay of BengalAuthors are grateful to the Ministry of Earth Sciences MoES and National Institute of Ocean Technology NIOT for the ship ORV Sagar Nidhi facility and the Captain of the vessel and other crew for cooperation during the cruise This work benefited from the advice of Dr T Srinivasa Kumar and Dr A A Lotlikar SATCORE Project Indian National Center for Ocean Information Services INCOIS The authors thank Prof Dr D WolfGladrow Editor and an anonymous reviewer for their critical helpful comments which significantly improved the manuscript Financial assistance from INCOIS INCOIS/093/2007 and further financial assistance from CSIR 210802/10/EMRII are gratefully acknowledged

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