- Q: What is your current research topic?
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Nutrient dynamics in subtropical waters using a highly sensitive analytical method. Nutrients such as nitrogen and phosphorus exist in extremely low concentrations in the surface layers of subtropical waters. The purpose of this research is to develop a highly sensitive technique for measuring these minute amounts of nutrients and to understand their distribution and circulation.
- Q: What motivated you to start your research?
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- Phytoplankton absorbs CO? and creates organic matter through photosynthesis, regulating the Earth's CO? concentration. Nutrients are required for phytoplankton photosynthesis, but even though photosynthesis is taking place in subtropical oceans in particular, the nutrient supply process that supports it is not well understood and remains a mystery. In order to solve this mystery, we have begun research into nutrient dynamics using highly sensitive analytical techniques. We are also working on research, with the belief that investigating the distribution and circulation of nutrients in the ocean will lead to elucidation of the CO? absorption mechanism of phytoplankton, which will contribute to understanding the current state of the global environment and predicting its future.
- Q: What is interesting and rewarding about your research?
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To measure nutrients with high sensitivity, it is necessary to develop a new analytical method, and establishing it is both difficult and rewarding. In conventional spectrophotometric analysis, light is applied to a 1-centimeter cell and the light absorbed (absorbance) is measured, but this makes it difficult to measure low concentrations of nutrients in subtropical seas. To increase absorbance, we adopted a thin and long cell called LWCC, which is 0.5 to 2.0 meters long, but it was difficult to incorporate it into the analysis system. When measuring, a reagent is reacted with seawater to color it and then sent to the cell. We adjusted the concentration of the reagent, improved clogging and flow within the cell, and finally established the method through trial and error.
- Q: What kind of social impact can you expect from your research?
Please tell me about short-term (1-2 years from now) and long-term (up to 10 years from now) plans.
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In the short term, we will establish new methods and introduce them to in-situ observations to obtain new data on nutrients in the subtropical ocean. Analysis of these data will shed new light on the dynamics of nutrients, and we can publish the results within a few years.
As a long-term contribution, from 2022 we will begin environmental monitoring of nutrients and other conditions in subtropical waters using the Shioji Maru, owned by our university. There are many things that can be predicted using computers, but if we do not see what is actually happening in the ocean, we will lose sight of reality. Continuing real-water monitoring for 10 to 20 years, which is possible only at a university with a training ship, will be an extremely important initiative in understanding the rapidly changing global environment. - Q: What about contributing to the SDGs?
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- Our research falls under Goal 13: Take urgent action to combat climate change and protect the life of the oceans and seas. We believe that elucidating the mechanism by which phytoplankton, the primary producers in marine ecosystems, absorb CO14 will be useful in combating climate change and conserving ecosystems.
- Q: What is the significance of conducting research at Tokyo University of Marine Science and Technology?
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- Tokyo University of Marine Science and Technology is one of the few universities that can conduct on-site observations using training ships. By directly understanding the marine environment using a ship, we can collect real-world data that cannot be obtained through simulations. The environment at Tokyo University of Marine Science and Technology, which allows for this type of field-based research, is a great advantage in advancing my research theme.
- Q Research Policy
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- By reviewing various academic papers and participating in academic conferences, I obtain a lot of new information. This is important because it gives birth to new ideas. Also, oceanographic observations on a training ship cannot be done alone. While valuing the captain, crew members, and researchers who collaborate with me, I also value expanding that community.
- Associate Professor Fuminori Hashihama's OA paper is here
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Paper title: Nanomolar phosphate supply and its recycling drive net community production in the subtropical North Pacific
Authors and co-authors: Fuminori Hashihama, Ichiro Yasuda, Aki Kumabe, Mitsuhide Sato, Hiroshi Sasaoka, Yosuke Iida, Takuhei Shiozaki, Hiroaki Saito, Jota Kanda, Ken Furuya, Philip W. Boyd, Masao Ishii
Published in: Nature Communications Publication date: June 2021
DOI: 10.1038/s41467-021-23837-y
