The Structure of Bacterial Communities and Its Chemoautotrophic Players in Sulfur-rich Sediments of Shallow Water HTVs off Kueishan Island, Taiwan. hydrothermal vent metagenome

The diversity of chemoautotrophs in the sulfur-rich sediments of the HTVs off Kueishan Island was studied. Our previous study already demonstrated the dominance of mesophilic chemoautotrophic sulfur oxidization bacteria Sulfurovum and Sulfurimonas within Epsilonproteobacteria there. They can use elemental sulfur or thiosulfate (or sulfide in the case of Sulfurimonas) as their sole electron donor and oxygen or nitrate as the electron acceptor. From the full genomic sequences of Sulfurimonas and metagenomics revovered Sulfurovum genomes, related genes of rTCA cycle were detected. The role of rTCA cycle in the sulfur-rich sediment of shallow water HTVs of Kueishan Island need to be further confirmed. In our study, combined with information on microbial structure revealed by 16S rRNA gene, genes encoding key enzymes for two important carbon fixation pathways, the CBB cycle [key enzymes: ribulose1, 5-bisphosphate carboxylase/oxygenase (RubisCO) forms I and II, genes: cbbL and cbbM, respectively] and the rTCA cycle (key enzyme: ATP citrate lyase: genes aclB), will be studied to evaluate the autotrophic potential of vent communities.