Labs and Faculty
Intra-University Cooperative Laboratories
Laboratory of Advanced Marine Bioscience

HAMASAKI Koji Prof. Ph.D.

Other Affiliations: Atmosphere and Ocean Research Institute

Microbial oceanography


Microbial functions, Biodiversity, Biogeochemical cycles, Air-sea interaction


Millions of microbes are living in a drop of seawater. I believe that these tiny but indispensable microorganisms lead us into deeper understandings of the connection between the earth and life. What kinds of microorganisms are there in the sea and what are they doing? Let's go exploring the sea of microorganisms with us.


The huge amount of organic carbon corresponding to the whole carbon amount in atmospheric carbon dioxide is dissolved in the ocean. Prokaryotic microorganisms such as bacteria and archaea are the only users of this huge carbon pool and deeply involve in the global carbon cycle. In addition to carbon dioxide, microbial processes are also involved in the dynamics of greenhouse-related gases such as nitrous oxide, methane, and dimethyl sulfide. A deeper understanding of marine ecosystems and biogeochemical cycles through these studies of microbial processes should lead to measures to address the environmental problems we face. It is not easy to study the vast ocean, but it is possible to carry out wide-area observations that cross the Pacific Ocean on board using a large research vessel and time-series observations at marine observatory stations. By collaborating with researchers of diverse fields such as physics, chemistry, and biology, we are taking on the challenge of various research issues in the ocean.

  • Fluorescence microscope images of diatom cells (red), the major photosynthetic producers in the ocean, and marine bacteria (green) that proliferate actively around them.


2018-present Professor, Atmosphere and Ocean Research Institute, The University of Tokyo
2012-2015 Technical Advisor, Ministry of Education, Culture, Sports, Science and Technology
2010-2018 Associate Professor, Atmosphere and Ocean Research Institute, The University of Tokyo
2006-2010 Associate Professor, Ocean Research Institute, The University of Tokyo
2002-2006 Assistant Professor, Graduate School of Biosphere Science, Hiroshima University
2000-2002 Visiting Scholar, Scripps Institution of Oceanography, University of California San Diego
1997-2000 Assistant Professor, Faculty of Applied Biological Science, Hiroshima University
1995-1997 Assistant Professor, Department of Bioengineering, School of Engineering, Soka University
1994-1995 Research Fellow of the Japan Society for the Promotion of Science, Marine Microbiology Division, Ocean Research Institute, University of Tokyo.