Open AccessAnalysis of bacterial and protozoan communities in an aquifer contaminated with monoaromatic hydrocarbons
Author(s) -
Zarda Boris,
Mattison Geoffrey,
Hess Annatina,
Hahn Dittmar,
Höhener Patrick,
Zeyer Josef
Publication year - 1998
Publication title -
fems microbiology ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.377
H-Index - 155
eISSN - 1574-6941
pISSN - 0168-6496
DOI - 10.1111/j.1574-6941.1998.tb00532.x
Subject(s) - biology , contamination , aquifer , environmental health , microbiology and biotechnology , ecology , groundwater , medicine , geotechnical engineering , engineering
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. 0.1×10 8 cells and 0.2×10 8 cells g −1 of core material [dry wt.], respectively) to the high‐contaminated core C (2.4×10 8 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. 1:10 3 , 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.