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Analysis of bacterial and protozoan communities in an aquifer contaminated with monoaromatic hydrocarbons

Zarda, Boris ; Mattison, Geoffrey ; Hess, Annatina ; Hahn, Dittmar ; Höhener, Patrick ; Zeyer, Josef

In: FEMS Microbiology Ecology, 1998, vol. 27, no. 2, p. 141-152

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    Title
    • Analysis of bacterial and protozoan communities in an aquifer contaminated with monoaromatic hydrocarbons
    Author
    • Zarda, Boris. Swiss Federal Institute of Technology (ETH Zurich), Institute of Terrestrial Ecology, Soil Biology, Grabenstr. 3, CH-8952 Schlieren, Switzerland
    • Mattison, Geoffrey. Swiss Federal Institute of Technology (ETH Zurich), Institute of Terrestrial Ecology, Soil Biology, Grabenstr. 3, CH-8952 Schlieren, Switzerland
    • Hess, Annatina. Swiss Federal Institute of Technology (ETH Zurich), Institute of Terrestrial Ecology, Soil Biology, Grabenstr. 3, CH-8952 Schlieren, Switzerland
    • Hahn, Dittmar. Swiss Federal Institute of Technology (ETH Zurich), Institute of Terrestrial Ecology, Soil Biology, Grabenstr. 3, CH-8952 Schlieren, Switzerland
    • Höhener, Patrick. Swiss Federal Institute of Technology (ETH Zurich), Institute of Terrestrial Ecology, Soil Biology, Grabenstr. 3, CH-8952 Schlieren, Switzerland
    • Zeyer, Josef. Swiss Federal Institute of Technology (ETH Zurich), Institute of Terrestrial Ecology, Soil Biology, Grabenstr. 3, CH-8952 Schlieren, Switzerland
    Document Type
    • Postprint
    OAI-PMH Identifier
    • oai:doc.rero.ch:300187
    Summary
    Bacterial and protozoan communities were examined in three cores (A, B and C) from an aquifer located at an abandoned refinery near Hünxe, Germany. Cores were removed along a transect bordering a plume containing various monoaromatic hydrocarbons. Monoaromatic hydrocarbons could not be detected in the unsaturated zone in any core but were present in the saturated zones of core C (between 280 and 42 600 μmol kg−1 of core material [dry wt.]) and cores A and B (between 30 and 190 μmol kg−1 of core material [dry wt.]). Xylene isomers accounted for 50-70% of monoaromatic hydrocarbons in all cores. The number of DAPI-stained bacteria was found to increase from the low-contaminated cores A and B (approx. 0.1×108 cells and 0.2×108 cells g−1 of core material [dry wt.], respectively) to the high-contaminated core C (2.4×108 cells g−1 of core material [dry wt.]). The higher bacterial numbers in core C were found to coincide with a higher detection rate obtained by in situ hybridization using probe Eub338 to target the domain Bacteria (13-42% for core C as compared to 3-25% for cores A and B, respectively). Proteobacteria of the δ-subdivision (which includes many sulfate-reducing bacteria) were the most predominant of the groups investigated (7-15% of DAPI-stained bacteria) and were followed by Proteobacteria of the γ- and β-subdivisions (4% and 1% of DAPI-stained bacteria, respectively). The total numbers of protozoa and bacteria determined by direct counting occurred in a ratio of approx. 1:103, which was independent of depth or core examined. Most probable number analysis combined with a subsequent classification of the culturable protozoa revealed nanoflagellates as the major component of the protozoan community. Naked amoebae became increasingly more encysted with depth, except in the high-contaminated core C where vegetative trophozoites were present in the saturated zone. The co-occurrence of bacteria and protozoa in association with high concentrations of monoaromatic hydrocarbons suggests the involvement of trophic interactions in the process of biodegradation