2:05 PM - 2:20 PM
[BBG01-02] Microbial communities in brucite-carbonate chimneys and clam colony sediments in the Shinkai Seep Field, the deepest serpentinite-hosted vent system in the Southern Mariana Forearc
Keywords:serpentinization reaction, chimney, sediments, Calyptogena colony
Previous studies have described two types of chimneys: those rich in brucite and growing rapidly in relatively active seeping alkaline fluid (Type 1), and those with a higher calcium carbonate content, the dense surface cover of polychaetes and snails, and slow growth in relatively calm seeping (Type 2). In the alpha diversity analysis, Type 1 chimneys and marker sediments, which are considered to be heavily supplied with alkaline fluids, have relatively low diversity and higher fluid supply (Okumura et al., 2016). LEfSe analysis pick upped marker phylotypes sulfur-oxidizing bacteria, methane-oxidizing bacteria, methanogenic archaea were found in the Type I chimney and marker precipitates, methylotrophic bacteria in the Type II chimney, and sulfate-reducing bacteria and sulfur-oxidizing bacteria in sediments. In this seep field, it is clear that diverse geochemical conditions cause differences in microbial communities due to differences in the supply of alkaline fluid related to serpentinization. This background is thought to support a high-density faunal community not found at other sites.
References
[1] Ohara et al. (2012) Proc. Natl. Acad. Sci. U. S. A., 109, 2831–2835.
[2] Okumura et al. (2016) Geochem. Geophys. Geosys. 17, 3775–3796.