title: Eukaryotic diversity in an anaerobic aquifer polluted with landfill leachate.
abstract: 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, as well as culturing, were employed to obtain insight into the sediment-associated eukaryotic community composition in an anaerobic sandy aquifer polluted with landfill leachate (Banisveld, The Netherlands). The microeukaryotic community at a depth of 1 to 5 m below the surface along a transect downgradient (21 to 68 m) from the landfill and at a clean reference location was diverse. Fungal sequences dominated most clone libraries. The fungal diversity was high, and most sequences were sequences of yeasts of the Basidiomycota. Sequences of green algae (Chlorophyta) were detected in parts of the aquifer close (<30 m) to the landfill. The bacterium-predating nanoflagellate Heteromita globosa (Cercozoa) was retrieved in enrichments, and its sequences dominated the clone library derived from the polluted aquifer at a depth of 5 m at a location 21 m downgradient from the landfill. The number of culturable eukaryotes ranged from 10(2) to 10(3) cells/g sediment. Culture-independent quantification revealed slightly higher numbers. Groundwater mesofauna was not detected. We concluded 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.
authors.affiliation: Department of Molecular Cell Physiology, Faculty of Earth and Life Sciences, VU University Amsterdam, De Boelelaan 1085, 1081HV Amsterdam, The Netherlands.
authors.forename: Traian
authors.initials: T
authors.lastname: Brad
authors.forename: Martin
authors.initials: M
authors.lastname: Braster
authors.forename: Boris M
authors.initials: BM
authors.lastname: van Breukelen
authors.forename: Nico M
authors.initials: NM
authors.lastname: van Straalen
authors.forename: Wilfred F M
authors.initials: WF
authors.lastname: Röling
mesh_terms: D000693:Anaerobiosis; D000818:Animals; D001419:Bacteria / Q000254:growth & development; D017753:Ecosystem; D004591:Electrophoresis, Polyacrylamide Gel; D056890:Eukaryota / Q000254:growth & development; D005057:Eukaryotic Cells / Q000145:classification*; D020387:Food Chain; D005618:Fresh Water / Q000737:chemistry / Q000382:microbiology / Q000469:parasitology; D005658:Fungi / Q000254:growth & development; D019015:Geologic Sediments / Q000737:chemistry / Q000382:microbiology / Q000469:parasitology; D008969:Molecular Sequence Data; D009426:Netherlands; D010802:Phylogeny; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D017422:Sequence Analysis, DNA; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014877:Water Pollution, Chemical
chemical_list: D012337:RNA, Ribosomal, 18S; D014874:Water Pollutants, Chemical