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Production of macroaggregates from dissolved exopolymeric substances (EPS) of bacterial and diatom origin

DRS at CSIR-National Institute of Oceanography

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Title Production of macroaggregates from dissolved exopolymeric substances (EPS) of bacterial and diatom origin
 
Creator Bhaskar, P.V.
Grossart, H.P.
Bhosle, N.B.
Simon, M.
 
Subject macroscopic organic aggregates
bacteria
diatoms
exopolymeric substances
aggregation
TEP
CSP
 
Description Exopolymeric substance (EPS) isolated from a pure culture of the marine bacterium Marinobacter sp. and the marine diatom Skeletonema costatum (axenic) were partially purified, chemically characterized and used as dissolved organic matter (DOM) for the production of macroaggregates. The role of organic particles such as transparent exopolymeric particles (TEP) and Coomassie stained particles (CSP) in the production of macroaggregates was experimentally assessed. Three experimental rolling tanks containing sterile medium with 1) EPS, 2) EPS + live diatom cells and 3) EPS + killed bacteria and 3 control tanks without any added EPS were used for macroaggregate production. Changes in abundance and average size of macroaggregates were monitored using image analysis, whereas TEP and CSP were enumerated microscopically. In the presence of microbial EPS, macroaggregates of a size of 23 to 35 mm2 were produced. Aggregate size and abundance varied considerably with both time and source of EPS. No correlation was observed for macroaggregate size and abundance with either TEP or CSP. One-way ANOVA demonstrated significant differences in the variance of particle abundance and size in tanks having only EPS or in combination with living diatom cells. Our data suggest that production of macroaggregates was influenced by polymer chemistry and surface properties of colliding particles whereas TEP and CSP concentrations were influenced by molecular weight of EPS and the presence of growing cells. Interestingly, macroaggregates were formed in the near absence of TEP and CSP, highlighting the role of other unknown processes in the transformation of DOM to particulate organic matter (POM) in aquatic environments.
CSIR-SRF and UGC-DAAD for fellowship
 
Date 2006-05-05T06:36:40Z
2006-05-05T06:36:40Z
2005
 
Type Journal Article
 
Identifier FEMS Microbiology Ecology, vol. 53(2), 255-264.
http://drs.nio.org/drs/handle/2264/91
 
Language en_US
 
Rights Copyright with publisher
 
Format 474356 bytes
application/pdf
 
Publisher Elsevier