Microbial Diversity in Mid Indian Ocean Hydrothermal Vent Area and Comparison with That of Law Basin in South Pacific Ocean

Abstract

Deep-Sea Hydrothermal Vent has been interested because of its unique chemolithotrophic ecosystems. Hydrothermal systems could be divided into fast expanding type and slow expanding type and still extensively studied on fast expanding types. Fast Expanding Ridges are based on basalt fluid and high temperature but vent systems in slowly expanding ridges are based on diverse rock materials and also support diverse ecosystems depend on vent types. Korea started exploration of Indian Ocean hydrothermal vent from 2017 with R/V Isabu and the program including exploration of microbial diversity. In the year 2017 depth distribution of microbial diversity in water columns and microbial diversity near suspected hydrothermal vent area had been analyzed from 3 different sites in mid Indian Ocean Ridge. Predominant bacterial genera in the surface water were revealed as members of a typical oligotrophic ocean such as Prochlorococcus, Pelagibacter ubique, and Alteromonas macleodii. Sulfur oxidizing Epsilonproteobacteria distributed in a wide range of water columns. In sediments samples, proportion of Archaea was very low and hard to found signals of hyperthermophilic microorganisms. Additionally, proportion of Epsilomproteobacteria or Zetaproteobacteria in sediments was lower compared to that of active vent area. These results was not very different from reports on inactive vent systems but bring up possibility of reduced sulfur spe Fast Expanding Ridges are based on basalt fluid and high temperature but vent systems in slowly expanding ridges are based on diverse rock materials and also support diverse ecosystems depend on vent types. Korea started exploration of Indian Ocean hydrothermal vent from 2017 with R/V Isabu and the program including exploration of microbial diversity. In the year 2017 depth distribution of microbial diversity in water columns and microbial diversity near suspected hydrothermal vent area had been analyzed from 3 different sites in mid Indian Ocean Ridge. Predominant bacterial genera in the surface water were revealed as members of a typical oligotrophic ocean such as Prochlorococcus, Pelagibacter ubique, and Alteromonas macleodii. Sulfur oxidizing Epsilonproteobacteria distributed in a wide range of water columns. In sediments samples, proportion of Archaea was very low and hard to found signals of hyperthermophilic microorganisms. Additionally, proportion of Epsilomproteobacteria or Zetaproteobacteria in sediments was lower compared to that of active vent area. These results was not very different from reports on inactive vent systems but bring up possibility of reduced sulfur spe