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Enumeration of bacteria from a Trichodesmium spp. bloom of the eastern Arabian Sea: Elucidation of their possible role in biogeochemistry

DRS at CSIR-National Institute of Oceanography

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Title Enumeration of bacteria from a Trichodesmium spp. bloom of the eastern Arabian Sea: Elucidation of their possible role in biogeochemistry
 
Creator Basu, S.
Matondkar, S.G.P.
Furtado, I.
 
Subject carbon-flux
algal bloom
Trichodesmium
organic matter
 
Description The carbon-flux via algal bloom events involves bacteria as an important mediator. The present study, carried out during the spring inter-monsoon month of April 2008 onboard CRV Sagar Manjusha-06 in the Eastern Arabian Sea, addresses the bloom-specific flow of carbon to bacteria via chromophoric dissolved organic matter (CDOM). Eleven stations monitored were located in the coastal, shelf and open-ocean areas off Ratnagiri (16 degrees 59?N, 73 degrees 17?E), Goa (15 degrees 30?N, 73 degrees 48?E) and Bhatkal (13 degrees 58?N, 74 degrees 33?E) coasts. Visible bloom of ?saw-dust? color in the Ratnagiri shelf were microscopically examined and the presence of cyanobacteria Trichodesmium erythraeum and T. thieabautii with cell concentrations as high as 3.05 x 10 sup(6) trichomes L sup(-1) was recorded. Total bacterial counts (TBC) varied between 94.09 x 10 sup(8) cells L sup(-1) in the bloom to 1.34 x 10 sup(8) cells L sup(-1) in the non-bloom area. Chromophoric dissolved organic matter (CDOM) concentrations averaged 2.27 + or -3.02 m sup(-1) (absorption coefficient 325 nm) in the bloom to 0.28 + or -0.07 m sup(-1) in the non-bloom waters respectively. CDOM composition varied from a higher molecular size with lower aromaticity in the bloom to lower molecular size and increased aromaticity in the non-bloom areas respectively. Strong positive relationship of TBC with Chlorophyll a (R sup(2)=0.65, p < 0.01) and CDOM concentrations (R sup(2)=0.8373, p=0.01) in the bloom area indicated hydrolysis and/or uptake of CDOM by bacteria. Absorption by mycosporine-like amino acid palythene was recorded in the filtrate of bloom. Morphotypes of Trichodesmium-associated bacteria revealed a higher frequency of Gram-positive rods. The role of bacteria in relation to changing CDOM nature and as a factor in affecting oxygen content of the water column is discussed in context of the Arabian Sea
 
Date 2011-04-08T10:53:33Z
2011-04-08T10:53:33Z
2011
 
Type Journal Article
 
Identifier Journal of Applied Phycology, vol.23(2); 2011; 309?319
http://drs.nio.org/drs/handle/2264/3835
 
Language en
 
Rights An edited version of this paper was published by Springer. This paper is for R & D purpose and Copyright [2010] Springer.
 
Publisher Springer