title: Vertical distribution of major sulfate-reducing bacteria in a shallow eutrophic meromictic lake.
abstract: The vertical distribution of sulfate-reducing bacteria was investigated in a shallow, eutrophic, meromictic lake, Lake Harutori, located in a residential area of Kushiro, Japan. A steep chemocline, characterized by gradients of oxygen, sulfide and salinity, was found at a depth of 3.5-4.0 m. The sulfide concentration at the bottom of the lake was high (up to a concentration of 10.7 mM). Clone libraries were constructed using the aprA gene, which encodes adenosine-5'-phosphosulfate reductase subunit A, in order to monitor sulfate-reducing bacteria. In the aprA clone libraries, the most abundant sequences were those from the Desulfosarcina-Desulfococcus (DSS) group. A primer set for a DSS group-specific 16S rRNA gene was used to construct another clone library, analysis of which revealed that the uncultured group of sulfate-reducing bacteria, SEEP SRB-1, accounted for nearly half of the obtained sequences. Quantification of the major bacterial groups by catalyzed reporter deposition-fluorescence in situ hybridization demonstrated that the DSS group accounted for 3.2-4.8% of the total bacterial community below the chemocline. The results suggested that the DSS group was one of the major groups of sulfate-reducing bacteria and that these presumably metabolically versatile bacteria might play an important role in sulfur cycling in Lake Harutori.
authors.affiliation: The Institute of Low Temperature Science, Hokkaido University, Kita-19, Nishi-8, Kita-ku, Sapporo 060-0819, Japan. Electronic address: kkubo@pop.lowtem.hokudai.ac.jp.
authors.forename: Kyoko
authors.initials: K
authors.lastname: Kubo
authors.affiliation: The Institute of Low Temperature Science, Hokkaido University, Kita-19, Nishi-8, Kita-ku, Sapporo 060-0819, Japan. Electronic address: kojimah@pop.lowtem.hokudai.ac.jp.
authors.forename: Hisaya
authors.initials: H
authors.lastname: Kojima
authors.affiliation: The Institute of Low Temperature Science, Hokkaido University, Kita-19, Nishi-8, Kita-ku, Sapporo 060-0819, Japan.
authors.forename: Manabu
authors.initials: M
authors.lastname: Fukui
mesh_terms: D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D020564:Deltaproteobacteria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D007564:Japan; D060106:Lakes / Q000382:microbiology*; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D050862:Oxidoreductases Acting on Sulfur Group Donors / Q000235:genetics; D010100:Oxygen / Q000032:analysis; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D054712:Salinity; D017422:Sequence Analysis, DNA; D013431:Sulfates / Q000378:metabolism*; D013440:Sulfides / Q000032:analysis; D014867:Water / Q000737:chemistry
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D013431:Sulfates; D013440:Sulfides; D014867:Water; D050862:Oxidoreductases Acting on Sulfur Group Donors; C019618:adenylylsulfate reductase; D010100:Oxygen
keywords: Meromictic lake; Sulfate-reducing bacteria; Sulfide; aprA