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Aerobic biofilms grown from Athabasca watershed sediments are inhibited by increasing concentrations of bituminous compounds.

ABSTRACT: Sediments from the Athabasca River and its tributaries naturally contain bitumen at various concentrations, but the impacts of this variation on the ecology of the river are unknown. Here, we used controlled rotating biofilm reactors in which we recirculated diluted sediments containing various concentrations of bituminous compounds taken from the Athabasca River and three tributaries. Biofilms exposed to sediments having low and high concentrations of bituminous compounds were compared. The latter were 29% thinner, had a different extracellular polysaccharide composition, 67% less bacterial biomass per ?m2, 68% less cyanobacterial biomass per ?m2, 64% less algal biomass per ?m2, 13% fewer protozoa per cm2, were 21% less productive, and had a 33% reduced content in chlorophyll a per mm2 and a 20% reduction in the expression of photosynthetic genes, but they had a 23% increase in the expression of aromatic hydrocarbon degradation genes. Within the Bacteria, differences in community composition were also observed, with relatively more Alphaproteobacteria and Betaproteobacteria and less Cyanobacteria, Bacteroidetes, and Firmicutes in biofilms exposed to high concentrations of bituminous compounds. Altogether, our results suggest that biofilms that develop in the presence of higher concentrations of bituminous compounds are less productive and have lower biomass, linked to a decrease in the activities and abundance of photosynthetic organisms likely due to inhibitory effects. However, within this general inhibition, some specific microbial taxa and functional genes are stimulated because they are less sensitive to the inhibitory effects of bituminous compounds or can degrade and utilize some bitumen-associated compounds.

SUBMITTER: Yergeau E

PROVIDER: S-EPMC3837753 | biostudies-literature | 2013 Dec

REPOSITORIES: biostudies-literature

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Aerobic biofilms grown from Athabasca watershed sediments are inhibited by increasing concentrations of bituminous compounds.

Yergeau Etienne E Lawrence John R JR Sanschagrin Sylvie S Roy Julie L JL Swerhone George D W GD Korber Darren R DR Greer Charles W CW

Applied and environmental microbiology 20130920 23

Sediments from the Athabasca River and its tributaries naturally contain bitumen at various concentrations, but the impacts of this variation on the ecology of the river are unknown. Here, we used controlled rotating biofilm reactors in which we recirculated diluted sediments containing various concentrations of bituminous compounds taken from the Athabasca River and three tributaries. Biofilms exposed to sediments having low and high concentrations of bituminous compounds were compared. The lat ...[more]

PMID: 24056457

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Aerobic biofilms grown from Athabasca watershed sediments are inhibited by increasing concentrations of bituminous compounds.

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Aerobic biofilms grown from Athabasca watershed sediments are inhibited by increasing concentrations of bituminous compounds.

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