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Grazing of particle-associated bacteria - An elimination of the non-viable fraction

DRS at CSIR-National Institute of Oceanography

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Title Grazing of particle-associated bacteria - An elimination of the non-viable fraction
 
Creator Gonsalves, M.J.B.D.
Fernandes, S.O.
LakshmiPriya, M.
LokaBharathi, P.A.
 
Subject Microbiology::General
Aquatic communities::Zooplankton
Chemistry and biogeochemistry::Organic compounds
 
Description Quantification of bacteria being grazed by microzooplankton is gaining importance since they serve as energy subsidies for higher trophic levels which consequently influence fish production. Hence, grazing pressure on viable and non-viable fraction of free and particle-associated bacteria in a tropical estuary controlled mainly by protist grazers was estimated using the seawater dilution technique. In vitro incubations over a period of 42 h showed that at the end of 24 h, growth coefficient (k) of particle-associated bacteria was 9 times higher at 0.546 than that of free forms. Further, ?k? value of viable cells on particles was double that of free forms at 0.016 and 0.007, respectively. While bacteria associated with particles were grazed (coefficient of removal (g) = 0.564), the free forms were relatively less grazed indicating that particle-associated bacteria were exposed to grazers in these waters. Among the viable and non-viable forms, ?g? of non-viable fraction (particle-associated bacteria = 0.615, Free = 0.0086) was much greater than the viable fraction (particle-associated bacteria = 0.056, Free = 0.068). Thus, grazing on viable cells was relatively low in both the free and attached states. These observations suggest that non-viable forms of particle-associated bacteria were more prone to grazing and were weeded out leaving the viable cells to replenish the bacterial standing stock. Particle colonization could thus be a temporary refuge for the ?persistent variants? where the viable fraction multiply and release their progeny
 
Date 2017-03-01T09:41:56Z
2017-03-01T09:41:56Z
2017
 
Type Journal Article
 
Identifier Brazilian Journal of Microbiology, vol.48(1); 2017; 37-42
http://drs.nio.org/drs/handle/2264/5087
 
Language en
 
Rights This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) @ 2016
 
Publisher Elsevier