Naohiko Ohkouchi
Commendation
Development and applications of novel biogeochemical tools using organic matter and compound-specific isotope systematics
Major achievements
Dr. Ohkouchi has made significant contributions to the field of biogeoscience, particularly in three areas, through integrated analysis of organic matter combining various methods and the development of highly sensitive isotopic analysis methods at the nanomolar level. 1) Contributions to paleoceanography and paleoenvironmental studies using biomarkers and stable isotopes: Refinement of the alkenone paleotemperature proxy and developing porphyrin paleoenvironmental indicators to elucidate the marine ecosystem during the Cretaceous Oceanic Anoxic Events. 2) Applications of compound-specific nitrogen isotope analysis to food chain and biogeochemistry: The development of a method for decoding food webs based on nitrogen isotopic ratios of amino acids is groundbreaking in ecosystem studies, and has greatly advanced our understanding of both terrestrial and aquatic ecosystems, including the conservation of marine resources, such as the elucidation of the diet of juvenile eels. 3) Contribution to the understanding of the carbon cycle in the sub-seafloor and early Earth: By developing a highly sensitive analytical method for F430, a coenzyme involved in microbial methanogenesis, and applying it to deep-sea drilling samples, he has established an approach for studying methanogenesis and its dynamics in the subseafloor biosphere. This series of studies is revolutionary and outstanding in the field of biogeoscience.
Nominator
Asahiko Taira
Supporters
Yusuke Yokoyama, Yoshinori Takano