73.
Bacteria in the surface sediments of a subtropical mangrove habitat were investigated using a cultivation-independent molecular
approach. Phylogenetic analysis of nearly full-length 16S rRNA genes revealed a diversity of sequences that were mostly novel.
Members from the five subdivisions of the Proteobacteria were detected, and they collectively represented the majority (67%)
of the clone library. Sequence types affiliated with the Gammaproteobacteria constituted the largest portion (29%) of the
library, and many of them were related to free-living and symbiotic sulfur-oxidizing bacteria. The Epsilonproteobacteria were
the second most abundant group (16%), including only one sequence type clustering with PCR-generated bacterial clones previously
recovered from deep-sea sediments. A substantial portion (8%) of the clones grouped within the Deltaproteobacteria, a subdivision
with anaerobic sulfate or metal reduction as the predominant metabolic trait of its members. In addition, minor portions were
affiliated with the
Cytophaga–
Flexibacter–
Bacteroides group (9%), Actinobacteria (6%), Chloroflexi (5%), Firmicutes (4%), Fusobacteria (1%), and the Chlamydiae/Verrucomicrobia
group, Fibrobacteres/Acidobacteria group and Planctomycetes (each < 1%). These results significantly expand our knowledge
of the bacterial diversity of the unique mangrove environment.
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