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Bacteria–algae association in batch cultures of phytoplankton from a tropical reservoir: the significance of algal carbohydrates
Author(s) -
GIROLDO DANILO,
ORTOLANO PEDRO I. C.,
VIEIRA ARMANDO A. H.
Publication year - 2007
Publication title -
freshwater biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 156
eISSN - 1365-2427
pISSN - 0046-5070
DOI - 10.1111/j.1365-2427.2007.01764.x
Subject(s) - axenic , biology , algae , phytoplankton , botany , population , biomass (ecology) , roseobacter , bacteria , ecology , nutrient , clade , biochemistry , genetics , demography , sociology , gene , phylogenetic tree
Summary 1. The dissolved organic matter, especially carbohydrates, released by phytoplanktonic organisms may be ecologically important, through its influence on carbon cycling and microbial diversity. Here axenic cultures of three phytoplanktonic species, Cryptomonas tetrapyrenoidosa (Cryptophyceae), Staurastrum orbiculare (Zygnematophyceae) and Thalassiosira duostra (Bacillariophyceae), were inoculated with a microbial community from the same habitat in which the algae had been isolated (a tropical reservoir). Replicate cultures were not inoculated. 2. In both axenic and co‐inoculated cultures, phytoplanktonic density and extracellular carbohydrate production were monitored microscopically and by high performance liquid chromatography with a pulse amperometric detector, respectively. Bacterial population density was also monitored by epifluorescence microscope in the microbial co‐inoculated cultures. 3. Both bacterial and phytoplanktonic densities increased for 11 days in all cases. The use of extracellular carbohydrates by bacteria was also showed for all phytoplanktonic species. Of the three species of phytoplankton, only T. duostra had a faster population growth in the presence of bacteria, and reached a higher biomass than in axenic culture.