Clarifying the Invisible Relationship Between the Ocean and Humans
We get seafood from the ocean, and they are indispensable for meal in Japan. But what determines the amount of marine lives? Humans have achieved rapid developments by burning fossil fuels and by converting nitrogen gas into ammonium to use as fertilizer in farmlands. The increased carbon dioxide and ammonia have dissolved invisibly into the ocean. However, do changes in the ocean environment caused by these substances not affect the amount of marine lives?
My research aims to elucidate the invisible relationship between the components dissolved in seawater and the plankton that can utilize them, thereby clarifying the interrelationship between the ocean and humans from both perspectives of food production and global environmental issues. By measuring the concentrations of nitrate ions and ammonium ions in seawater—substances required by phytoplankton for uptake and cell division—and by quantifying the amounts of organic matter such as proteins retained in organisms, I have been elucidating the connections between the ocean and humans, with a focus on the flow of nitrogen elements in the seas surrounding Japan. In the future, I hope to reveal such “interactions” in wider oceanic regions and to further advance the exploration of the still mysterious nature of the sea.
Educational approach
Aiming for Personal Growth Through Unraveling the Mysteries of the Ocean
In the Laboratory of Aquatic Biology and Environmental Science to which I belong, third-year undergraduate students take part in laboratory experiments in April for getting the basic skills such as how to use instruments and how to collect data. Furthermore, during the field practicum in July, we conduct surveys in Lake Hamana, discuss “what happened” and “why they happened” and then present their findings. Through such a curriculum, students can develop not only experimental techniques but also the ability to interpret data logically. After being assigned to the laboratory, students are expected to learn more advanced techniques. but we wanted the students to go on cruises, collect samples in cooperation with others, analyze the samples, and discover previously unknown phenomena through logical interpretation.
Ocean-going observations are greatly influenced by nature and are therefore “unreasonable” compared with on-land laboratory research. Understanding this “unreasonableness”—that is, developing tolerance—together with the autonomy and independence to do one’s best under unreasonable conditions, and the logical and rational thinking skills that come from interpreting results, are all essential qualities. Our goal is to nurture individuals who can acquire all these abilities and advance to the next stage of their careers.
Vision for industry-academia collaboration
Overcoming the Complexity of the Ocean and Seawater
The ocean serves as a sink for nitrogen and carbon compounds emitted by human activities. It had long been believed that once these substances dissolved into the vast ocean, their concentrations would be too low to detect. However, high-sensitivity analyses and long-term datasets have revealed that such nitrogen inputs are indeed altering the marine environment. On the other hand, although the concept of a “sink” often emphasizes the negative aspects, it has also been suggested that an appropriate amount of nutrient supply from terrestrial sources may contribute to enhancing biological productivity in the ocean. Thus, the marine environments are complex and highly heterogeneous. Therefore, understanding marine phenomena requires not only the application of advanced analytical techniques but also appropriate statistical processing. Moreover, seawater is a particularly challenging target for chemical analysis due to its many impurities. The analytical and interpretive expertise accumulated through oceanographic research can be valuable not only for evaluating the marine environments and ecosystems but also in many other fields. For example, the nutrient analysis methods we have developed are used not only for seawater analysis but also for measuring fertilizer components in soils.
