A research group led by Mariko Kozuka, a specially appointed researcher at the University of Tokyo, has succeeded in decoding the DNA of organisms preserved in marine sediments from 2.9 to 10 years ago in collaboration with Kyoto University and Kobe University.Since the identified organisms are of different species, reflecting different climates, it may be possible to infer past environmental changes.

 Submarine sediments are formed by the accumulation of dead organisms and organic matter containing useful information called biomarkers.Therefore, it has been used as an important record for understanding past ecosystems and environments.However, the species in which fossils and biomarkers are preserved are limited, and it was impossible to obtain genetic information because microorganisms decompose DNA in seafloor sediments.

 Therefore, the research group focused on the fact that microorganisms that use methane as a nutrient source suppress the activity of microorganisms that decompose DNA.Seafloor sediments in the cold seep zone where methane springs off Joetsu, Niigata Prefecture were collected.Then, using a unique DNA extraction method that can determine the base sequence from a very small amount of DNA, the sequence of fossil DNA originating from diatoms, radiolarians, seaweeds, land plants, etc. is obtained from a sample 10 years ago. I succeeded in doing so.For comparison, we also investigated points other than cold seeps and confirmed that fossil DNA was detected only up to about 3 years.It was clarified that the effect of methane springing out is advantageous for the preservation of fossil DNA.We also confirmed that the detected land plant species and their ages are consistent with the Japanese vegetation of the same period estimated by paleopollen research.

 This finding indicates that seafloor sediments also store information on terrestrial climate change, and by proceeding with research on past global warming, to understand the ongoing warming. It is said that it can provide important scientific data.

Paper information: [Geobiology] Eukaryotic diversity in late Pleistocene marine sediments around a shallow methane hydrate deposit in the Japan Sea

Tokyo University

Established in the 10th year of the Meiji era.A university with the longest history in Japan and at the forefront of Japanese knowledge

The University of Tokyo was established in 1877 (Meiji 10) by integrating the Tokyo Kaisei School and the Tokyo Medical School.Since its establishment, it has developed education and research in a unique way in the world as a leading university in Japan and an academic center for the fusion of East and West cultures.As a result, many human resources have been produced in a wide range of fields, and many research achievements […]

Kyoto University

Foster a free academic style based on the spirit of "self-respect for self-weight" and open up a world of creative learning.

With the motto of self-study, we will continue to maintain a free academic style that is not bound by common sense, and develop human resources who have both creativity and practical ability.We provide an inclusive learning space that allows for diverse and hierarchical choices so that students themselves can choose a solid future through valuable trial and error. […]

Kobe University

To an outstanding research university that shines with advanced research and fusion research

Kobe University, which is located in a port city open to the world, has 4 faculties and 10 faculties under the 15 university arts series of "humanities / human sciences", "social sciences", "natural sciences", and "life / medical sciences". It is a comprehensive university with a graduate school, one research institute and many centers. Based on the philosophy of "harmony between science and reality," we have strengths in both the humanities and science fields […]

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