N-151. Metabolic Diversity and Dynamics of the Deep-Sea Hydrothermal Vent Microbial Communities Revealed by Combined Molecular Approaches

F. Wang1, J. Meng1, H. Zhou2, X. Peng2, Y. Deng3, Z. He3, J. Zhou3, X. Xiao1;
1Third Inst. of Oceanography, Xiamnen, CHINA, 2Guanzhou Geochemistry Inst., China Academy of Sci., Guangzhou, CHINA, 3Univ. of Okalahoma, Norman, OK.

Background: The microbial communities in the deep-sea hydrothermal vent area are in dynamic. The overall metabolic diversity and dynamics of the microbial community in the deep-sea hydrothermal vent chimneys of Endeavour segment of the Juan de Fuca ridge, including the inner part (4243B), outer part (4243A) of a newly grown 5 day’s proto-chimney and a mature chimney (4143), were examined. Methods: The microbial diversity in the sulfide deposits were investigated by 16S rRNA gene analysis and functional gene approach. Geochip hybridization was used to detect the dynamic change of the communities. Results: A total of 113, 504 genes were detected in 4243B, 4243A respectively, while 5414 functional genes were found in the mature chimney, indicating a far more complex microbial community developed in the mature chimney. The genetic populations between 4243A, 4243B are substantially different (less than 2% of common genes), suggesting a rapid compositional changes of the microbial community during the development of the deep-sea hydrothermal vent chimney. Most of the genes detected in 4243A can be found in the mature, old chimney, suggesting that the basic microbial system in the chimney get stable within days. The primary producers in the three chimney samples mainly contain the Carvin Benson Bassham (CBB) reductive pentose phosphate pathway. Photosynthetic green-like cbbL genes are the major components in the 4243B sample, implying the existence of photosynthetic bacteria in the deep-sea environment. The microbial communities involved in methanogenesis, methane oxidation, sulfate reduction, nitrogen fixing, nitrate reduction, nitrification were also observed through the functional gene array approach.