Kyushu University Academic Staff Educational and Research Activities Database
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Tasuku Akagi Last modified date:2016.07.11

Professor / Material Science of Solar Planets
Department of Earth and Planetary Sciences
Faculty of Sciences

Graduate School
Undergraduate School

We do not have an appropriate tool to investigate the circulation driven by the activity of organisms. Ecology and biology, two of the central sciences of organisms, are not very useful to this purpose. Geochemistry seems promising to understand the most outer line of biology. Let me see how far I can tackle the problem using geochemistry. .
Academic Degree
Field of Specialization
Outline Activities
Geochemical studies of organism-mediated circulation of elements.
New geosciences incorporating interactions between organisms and environmental conditions.
Research Interests
  • Glacial cycles and diatom activities
    keyword : diatoms ocean elements environment
  • Diatoms and material circulation in the oceans
    keyword : diatoms ocean elements environment
  • Isotopic composition of water in Sphagnum peat
    keyword : water, Sphagnum, peat, oxygen isotope, hydrogen isotope
  • Incorporation of trace metals and silicic acid complexes in diatoms
    keyword : diatoms, opal, incorporation theory, metal-silicic acid complexes
  • Dissolution kinetics of diatom opal and determination of trace metals in diatom opal.
    keyword : diatoms, opal, rare earth elements, marine chemistry and geocycles of trace elements
  • Dissolution of minerals supplied by Kosa and its influence on the biosphere
    keyword : Kosa, weathering, bioorganisms
  • The role of plants in the global material cycles
    keyword : plants, weathering, carbon dioxide, silica
    2000.01~2006.01Contribution of plants to material transportation.
  • Reconstruction of the atmospheric CO2 concentration in the past using carbon isotope ratio of sphagnum form peat-lands
    keyword : atmospheric CO2 concentration, sea level, sphagnum, carbon isotope ratio, peat
    2004.01~2006.01Restoration of the atmospheric CO2 concentration in the past from carbon isotopic data of peat moss..
  • Carbon isotope ratio of the inclusions in natural diamonds: the study of the carbon geo-cycle involving the upper mantle.
    keyword : diamonds, carbon isotope ratio. inclusion, CO2
    2000.01~2006.01Carbon isotopic studies of volatile inclusions in natural diamonds..
  • Interaction between biota and the earth environment
    keyword : homeostasis, the earth environment. evolution of life, material cycles, the Gaia hypothesis, mathematical models
    2002.01~2006.01Regulative involvement of organisms in the earth environment..
Academic Activities
1. Tasuku Akagi, Saki Yasuda, Yoshihiro Asahara, Mariko Emoto, Kozo Takahashi, Diatoms spread a high εNd-signature in the Oceans, Geochemical Journal, 48, 2, 2014.04.
2. Tasuku Akagi, Rare earth element (REE)-silicic acid complexes in seawater to explain the incorporation of REEs in opal and the “leftover” REEs in surface water: new interpretation of dissolved REE distribution profiles, Geochimica et Cosmochimica Acta, 113, 2013.03.
3. Tasuku Akagi, Feng-fu Fu, Yayoi Hongo, Kozo Takahashi, Composition of rare earth elements in settling particles collected in the highly productive North Pacific Ocean and Bering Sea: Implications for siliceous-matter dissolution kinetics and formation of two REE-enriched phases, Geochim. Cosmochim. Acta, 75, 4857-4876, 2011.05.
4. S. Issei, Y. Igarashi, Y. Dokiya and T. Akagi, Two extreme types of mixing of dust with urban aerosols observed in Kosa particles: ‘after’ mixing and ‘on-the-way’ mixing, Atmospheric Environment, 44, 858-866 , 2010.07.
Other Research Activities
  • 2005.05.
Membership in Academic Society
  • The Japanese Society of Limnology
  • Geochemical Society
  • The Oceanographic Society of Japan
  • Geochemical Society of Japan
  • The Chemical Society of Japan
  • The Japan Society for Analytical Chemistry
  • Tne Geochemical Society of Japan Award for Young Researchers
Other Educational Activities
  • 2013.04, Geochemistry of and environmental changes by marine diatoms.