Hiroshima Shudo University

Graduate School of Science, The University of Tokyo

Kobe University

Kyoto University

（Kankyo Sogo Research Co.

Summary of Presentation

A research group consisting of Assistant Professor Masanori Okanishi of Hiroshima Shudo University, The University of Tokyo Graduate School of Science Misaki Marine Biological Station, Kobe University, Environmental Research Institute, Inc. and Kyoto University has developed a technique to analyze DNA released into the water from the mucus and excrement of invertebrates in the ocean (environmental DNA) and to determine the type of owner of the DNA. The ocean covers 70% of the Earth's surface area.

The oceans cover 70% of the Earth's surface area, and the organisms that live there provide us with great benefits. However, the survey of the types of organisms needed to estimate the marine environment requires diving and netting, which is time-consuming and labor-intensive. This process is even more difficult in the deep sea, which makes up the majority of the ocean.

In this study, targeting spider starfish, a member of the starfish family, we developed a technique to identify their species by examining the environmental DNA released by the starfish in the water. This technique, called "metabarcoding," has only been known for fish and crustaceans in Japanese waters, and there have been no studies in deep-sea areas.

This technique is expected to enable more detailed estimation of the marine environment by targeting not only highly mobile organisms such as fish and crustaceans, but also less mobile organisms that do not move from their environment. If applied to surveys of other organisms such as sea urchins and sea cucumbers in the future, it will make it possible for anyone to monitor organisms in deep waters that are difficult to access, over a wide area, and in a short period of time.

The results of this research were published in the Bulgarian scientific journal Metabarcoding & Metagenomics on February 28, 2023.

Figure: Spider starfish collected in Sagami Bay. Photo by Hisanori Kozuka (The University of Tokyo)

Technical Specialist Hisanori Kozuka of the Misaki Marine Biological Station, Graduate School of Science, The University of Tokyo participated in this research.

For more information, please visit the website of Hiroshima Shudo University.