Appl. Environ. Microbiol. doi:10.1128/AEM.02820-07
Copyright (c) 2008, American Society for Microbiology and/or the Listed Authors/Institutions. All Rights Reserved.
EUKARYOTIC DIVERSITY IN AN ANAEROBIC AQUIFER POLLUTED WITH LANDFILL LEACHATE
Traian Brad,
Martin Braster,
Boris M. van Breukelen,
Nico M. van Straalen,
and
Wilfred F.M. Röling*
Department of Molecular Cell Physiology, Faculty of Earth and Life Sciences, VU University Amsterdam, De Boelelaan 1085, 1081HV Amsterdam, The Netherlands; Department of Hydrology and Geo-Environmental Sciences, Faculty of Earth and Life Sciences, VU University Amsterdam, De Boelelaan 1085, 1081HV Amsterdam, The Netherlands; Institute of Ecological Science, Faculty of Earth and Life Sciences, VU University Amsterdam, De Boelelaan 1085, 1081HV Amsterdam, The Netherlands; NGI Ecogenomics Consortium, Amsterdam, The Netherlands
* To whom correspondence should be addressed. Email:
wilfred.roling{at}falw.vu.nl.
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Abstract |
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Eukaryotes may influence pollutant degradation processes in groundwater ecosystems by activities such as predation on bacteria and recycling of nutrients. Culture-independent community profiling and phylogenetic analysis of 18S rRNA gene fragments and culturing were employed to obtain insight in the sediment-associated eukaryotic community composition in an anaerobic sandy aquifer polluted with landfill leachate (Banisveld, The Netherlands). The microeukaryotic community at 1 to 5 m below the surface along a transect downgradient (21-68 m) from the landfill, and at a clean reference location, was diverse. Fungal sequences dominated most clone libraries. Fungal diversity was high with most sequences belonging to yeasts of the Basidiomycota. Sequences of green algae (Chlorophyta) were detected in parts of the aquifer close (< 30 m) to the landfill. The bacteria-predating nanoflagellate Heteromita globosa (Cercozoa) was retrieved in enrichments and its sequences dominated the clone library derived from the polluted aquifer at 5 m depth, 21 m downgradient of the landfill. The number of culturable eukaryotes ranged from 102 to 103 cells/g sediment. Culture-independent quantification revealed slightly higher numbers. Groundwater mesofauna was not detected. We conclude that the food chain in this polluted aquifer is short and consists of prokaryotes and fungi as decomposers of organic matter and protists as primary consumers of the prokaryotes.