Dr. Yasuhiro Kato is a professor in the Graduate School of Engineering at the University of Tokyo and director of the Ocean Resources Research Center for Next Generation at Chiba Institute of Technology. He is the marine resource geologist most closely associated with Japan’s discovery and development of rare-earth-elements rich deep sea mud near Minamitorishima, work that now underpins the country’s plans to test-mine these sediments as a strategic source of critical metals.

Trained as a geologist, Kato earned his bachelor’s, master’s, and Ph.D. degrees in geology from the University of Tokyo. He began his academic career as a JSPS Research Fellow and then assistant professor at Yamaguchi University before returning to the University of Tokyo’s School of Engineering, where he rose to full professor and later dean of the school. In parallel, he established the Ocean Resources Research Center for Next Generation in 2016 and took on a cross-appointment as its founding director and principal research scientist, building a joint research network that spans universities, national research institutes, and private companies.

Kato first came to global attention in 2011, when his University of Tokyo team reported that deep sea mud at multiple sites in the Pacific Ocean contains very high concentrations of rare earth elements and yttrium. In 2013, during the KR13-02 cruise in Japan’s exclusive economic zone around Minamitorishima, his group identified “extremely REE-rich mud” with total rare earth contents exceeding 7,000 parts per million, a grade far above most known land-based deposits. Subsequent work from his lab visualized the three-dimensional distribution of this mud and estimated that a 2,500 square kilometer area within the Minamitorishima zone alone may host more than 16 million tons of rare-earth oxides, leading him to describe the mud as a “groundbreaking mineral resource” with “the highest REY grade in the world.”

Through the Ocean Resources Research Center for Next Generation, Kato has broadened this discovery into an integrated program that links basic science, engineering, and commercialization. His team investigates how slow sedimentation, ocean circulation, and fish debris interact to concentrate rare earth elements in specific layers, revealing that the formation of extremely REE-rich mud is tied to major shifts in Earth’s climate about 34 million years ago. In parallel, he co-develops hybrid mining concepts for combining REE-rich mud and polymetallic nodules, including air-lift pumping systems for lifting mixed mud and nodules from 5,000 to 6,000 meters depth around Minamitorishima. As director of the center he writes that seafloor resources such as REE-rich mud and ferromanganese nodules can be developed only by “countries and companies with advanced technology and firm compliance” and that Japan has an opportunity to pioneer “a new way of truly sustainable resource development.”

Kato’s research feeds directly into Japan’s national effort to secure critical minerals. Distribution maps, geochemical models, and lifting-system simulations from his group are among the technical foundations for government-backed test mining of rare-earth-rich mud scheduled to begin near Minamitorishima in 2026. At the same time, his outreach projects, including the “Light from Minamitorishima” demonstration LED built from rare earths refined from seafloor mud, are designed to show the Japanese public that seafloor resources can move from scientific curiosity to tangible products that support high-tech manufacturing.