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Phylogenetic diversity of transition and anoxic zone bacterial communities within a near‐shore anoxic basin: Nitinat Lake
Author(s) -
Schmidtova Jana,
Hallam Steven J.,
Baldwin Susan A.
Publication year - 2009
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/j.1462-2920.2009.02044.x
Subject(s) - chemocline , anoxic waters , biology , phylotype , proteobacteria , anoxygenic photosynthesis , green sulfur bacteria , phototroph , ecology , water column , phylogenetic diversity , bacteria , phylogenetics , 16s ribosomal rna , paleontology , genetics , gene
Summary At two stations surveyed in Nitinat Lake, a ∼200‐m‐deep anoxic tidal fjord, sulfide was detected as close as 15 m from the surface. Biological characterization, determined from small subunit ribosomal RNA gene sequencing, of the chemocline and anaerobic zone revealed many sequences related to sulfur‐oxidizing bacteria, suggesting that sulfur cycling is a dominant process. γ‐ and ε‐ Proteobacteria related to thiotrophic symbionts, as well as Chlorobium sp., dominated the transition zone. These are expected to play a role in dark and phototrophic CO 2 fixation, respectively. ε‐ Proteobacteria phylotype abundance increased with depth, eventually comprising 69–97% of all sequences recovered from the anoxic zone. The vast majority (74%) of these phylotypes were affiliated with a novel Acrobacter sp. group (NITEP5). Quantification of NITEP5 revealed that up to 2.8 × 10 5 cells ml −1 were present in the anoxic zone. Surprisingly, although sequences related to known sulfate‐reducing bacteria were recovered from the transition zone, quantification of the dsr gene and 35 SO 4 2− uptake tests suggest that sulfate‐reduction within the water column is negligible. Overall, sequence diversity between different vertical zones was high, although the spatial segregation of γ‐ Proteobacteria, Chlorobi , and ε‐ Proteobacteria did not appear to vary significantly between seasons.