Earth Microbiology Research Group

Our group conducts research on microorganisms inhabiting seawater, deep subseafloor sediments and rocks, and we promote geomicrobiological studies from a holistic perspective encompassing the entire ocean. Through scientific ocean drilling and seawater sampling aboard research vessels, we collect subseafloor core samples and seawater to advance our understanding of the continuous biosphere extending from the oceanic water column to the deep subseafloor.

Through these studies, we aim to elucidate the interactions between microbial activity and material cycles linking seawater, seafloor sediments, and the subseafloor crust. Specifically, we investigate the spatial distributions and limits of microbial life in the oceanic water column and the subseafloor biosphere; the metabolic functions and evolutionary processes of microorganisms inhabiting deep subseafloor environments and seawater; microbial metabolic mechanisms involved in global elemental cycles across the entire ocean, including those related to rare metals; and the relationships between geological and paleoenvironmental changes and biological activity. By addressing these topics, we seek to uncover the principles governing the co-evolution of Earth and life, as well as to advance the understanding of marine ecosystem functions that interact with the Earth’s environment.

In particular, building on world-leading technologies applicable to both seawater and subseafloor samples for the detection and quantification of microbial cells, we develop and apply highly sensitive microbial detection, analysis, and isolation techniques applicable to seawater samples; nanoscale analytical methods using advanced microscopy; genomic and elemental analyses spanning from single cells to entire microbial communities; and metagenomic approaches that integratively analyze seawater and the subseafloor biosphere. Through original technological developments and cutting-edge interdisciplinary research that bridges Earth and life sciences, we aim to open new frontiers in geomicrobiology across the entire ocean.

1. Elucidating the structure and limits of the microbial biosphere extending throughout the entire ocean.
2. Understanding mechanisms of marine material cycles driven by microbial activity.
3. Revealing the evolution and origins of marine microorganisms.
4. Developing innovative analytical technologies to detect and characterize previously unknown microorganisms.