International Center for Environmental
Management of Enclosed Coastal Seas
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FY2020 Grants-in-Aid for young researchers

POSTED:May 21, 2020

In spite of the new system and the fact that the EMECS secretariat had to be closed due to the countermeasures against COVID-19, we received 11 applications for the grant as a result of your support. Four people have been selected as the grantees.

Call for research topic

The main topic of the research project is “Defining the Ideal Abundant Coastal Ecosystem”

  1. Studying the relationship between historical changes in the supply of sand and nutrient materials from rivers, including dams, and the changes in coastal ecosystems under their influence.
  2. Clarifying the dynamics of material circulation including suspended, adherent and benthic organisms due to artificial structures such as coastal and harbor dikes, reclamation, dredging and marine gravel extraction, and their chronological changes.
  3. Investigating the differences in the dynamics of material circulation including suspended, adherent and benthic organisms between sea areas with and without fish farms.
Title Name
Historical change of the water purification of bivalve species on the sandy tidal flats in Ariake Bay, Japanmore… Tomohiro Komorita Prefectural University of Kumamoto
Influences of coastal development on regional scale water and material dynamics in the Seto Inland Seamore… Yusuke Nakatani Department of Civil Engineering, Osaka University
Study on environmental load reduction by benthic organisms in aquaculture areasmore… Takero Yoshida Large-scale Experiment and Advanced-analysis Platform, Institute of Industrial Science, The University of Tokyo
Does the composition of nutrients influence the occurrences of harmful algal blooms in bluefin tuna farming?more… Saho Kitatsuji National Research Institute of Fisheries and Environment of Inland Sea

Historical change of the water purification of bivalve species on the sandy tidal flats in Ariake Bay, Japan

Division of Environmental Resources
Department of Environmental & Symbiotic Sciences
Faculty of Environmental & Symbiotic Sciences
Prefectural University of Kumamoto

Assoc. prof.Tomohiro Komorita

My name is Tomohiro Komorita and I work at the Faculty of Environmental Symbiosis at Prefectural University of Kumamoto. I am pleased that I have been selected for the Grants-in-Aid for Young Researchers in 2020 for the above-titled research project. This grant not only provides me with a research grant but also with an opportunity to receive guidance from distinguished professors, which I believe will be a big step in my future career development. I will do my best to live up to the honor of the research grant, and I look forward to working with you in the future.
My main study topic is “How can we make a smooth material cycle in coastal areas to use biological production sustainably?”. In particular, the Ariake Bay, which is my main field of study, has one of the largest sandy tidal flats in Japan, and we have found that the bivalve communities living in the vast tidal flats consume all the local primary production. Although there is still high productivity of bivalve population in the tidal flats of the Ariake Bay, the catching of short-necked clams and hard clams are still at a low level. At present, the Asian mussel, which is not suitable for our food resources, dominates on the tidal flats, therefore, we have not been able to bring out the full potential of the tidal flats. I am interested in “When did this change in the dominant species occur from short-necked clam to the Asian mussel?” and “Has the ability of bivalves to purify water, one of the most important ecosystem services they provide, changed over time?”. My goal is to propose concrete measures to make the sandy tidal flats in the Ariake Bay an ecosystem that is easy for humans to use in the future. In this research project, I will combine the data analysis provided by the Kumamoto prefecture and also conduct in-situ experiments on both primary and secondary productivity of tidal flats. In addition, we will examine whether long-term changes of the bivalves community remain in sediment core during that time.

Influences of coastal development on water and material dynamics at regional scale in the Seto Inland Sea

Department of Civil Engineering
Graduate School of Engineering
Osaka University

Asst. prof. Yusuke Nakatani

I have been selected for a research grant for young researchers in 2020. I have been working on the research topic, “Assessment of influences of coastal development on water and material cycle at Bay-Open sea scale in the Seto Inland Sea”.

I was born in Kyoto in 1983. After graduating from Doshisha Senior High School I studied civil engineering at Osaka University. After being assigned to a laboratory in my fourth year of undergraduate school, I studied under my current supervisor, Professor Shuzo Nishida, for six years until I completed my Ph.D., working on research into water and material circulation in Osaka Bay. After earning a doctorate, I spent a year at the University of Tokyo researching fishery management on sand lance fishing in the Seto Inland Sea. I returned to Osaka University in April 2013 and am running the laboratory with Professor Shuzo Nishida and Associate Professor Masayasu Irie. At present, I am widely engaged in research on the water environment using field surveys, numerical analysis, AI, and other methods to study lakes, rivers, watersheds, and coastal areas (see figure).

② About this research subject
In the Seto Inland Sea, many landforms have been altered as a result of reclamation of the sea and construction of breakwaters. Although coastal development is unavoidable in the future for disaster prevention, port development, and waste disposal, it is important to manage coastal ecosystems based on a correct understanding of their impact on the water environment. The effects of geomorphological alteration on the water environment have been evaluated at the port scale, focusing on the effects on the vicinity of projects, but in fact, the effects on the bay and open sea scale have not been fully evaluated.
However, in Osaka Bay, for example, it has recently been found that geomorphological alteration of the head of the bay not only locally alters the water environment at the port area scale, but also has a non-negligible effect on the residual current and water quality structure at the bay scale, as well as on the currents and material balance in the adjacent waters. In this research project, I aim to extend my study of Osaka Bay to the whole area of the Seto Inland Sea and to clarify the effects of geomorphological alteration on water and material cycles in the Seto Inland Sea by using a state-of-the-art 3D numerical model.
The numerical model constructed in this study is expected to be used to clarify the mechanisms of and examine the measures for various water environmental problems (such as red tide, hypoxia, eutrophication, oligotrophication, and COD management) that the Seto Inland Sea is currently facing. I would like to use this research as a starting point for future research on the water environment of the Seto Inland Sea, and hope to present results and knowledge that will contribute to our society.

Study on environmental load reduction by benthic organisms in aquaculture areas

Large-scale Experiment and Advanced-analysis Platform
Institute of Industrial Science
The University of Tokyo

Assis. prof.Takero Yoshida

I received my Ph.D. (Environmental Studies) from the Department of Ocean Technology, Policy, and Environment, Graduate School of Frontier Sciences, the University of Tokyo in March 2013, and have been working at the Institute of Industrial Science, the University of Tokyo as an Assistant Professor since August 2016. I have been engaged in research on marine observation and marine biology and environment. In particular, I have been conducting marine environmental observations using synthetic aperture radar and environmental impact assessments of marine use, including marine renewable energy and aquaculture. I am working on the harmonious use of the oceans and human beings to achieve coexistence and co-prosperity with the oceans.
In this study, I will conduct research on the effect of benthos in marine aquaculture areas to reduce the environmental burden of the marine environment. Aquaculture is mainly carried out in coastal areas, and self-pollution (Degradation of the surrounding environment due to farmed fish excrement and residual feed, which has a negative impact on the growth of farmed fish.) in fish farms has the potential to reduce productivity. The purpose of this study is to investigate the effect of absorbing fish waste by using benthos in the aquaculture area to reduce the environmental burden of the fish farm and the risk of productivity loss. In this study, the effect of environmental improvement of benthos will be examined through numerical simulations and simple tests in actual seawater conditions. For this study, I am considering using coho salmon fish farms in Miyagi and Iwate prefectures for test aquaculture farms and targeting sea cucumbers, gunnels etc. as benthos. In this study, the hydrodynamic-ecosystem coupled model used so far will be further improved to include the effects of benthos in the vicinity of a chum salmon aquaculture tank. For an at-sea trial, I am planning to verify the effect of reducing the environmental impact of benthos by installing fencing nets underneath the fish pens. In order to understand the effect of benthos in the vicinity of an existing fish pen for coho salmon, we need to develop a monitoring technology for benthos. By grasping the type and number of benthos around the fish pens, it is possible to examine how much of the fish farm’s excrement is absorbed. Basic research and development of monitoring methods for benthos around fish farms in actual sea areas will be conducted, such as an underwater camera set on the sea bottom. I will examine whether it is possible to monitor benthos that gather underneath the fish pen by installing the underwater camera on the seafloor in the long term. Through these studies, I aim to form a basis for measuring and understanding the effects of benthos on actual fish farms in the future.

Does the composition of nutrients influence the occurrences of harmful algal blooms in bluefin tuna farming?

Harmful Algal Blooms Group
Environmental Conservation Division
Environmental Fisheries Applied Techniques Research Department
Fisheries Technology Institute
National Research and Development Agency, Japan Fisheries Research and Education Agency

Saho Kitatsuji

I am grateful to be selected for the Grant in Aid for Young Researchers. I am a member of the Harmful and Toxic Algae Group, which studies red tide at the Fisheries Technology Research Institute of the National Fisheries Research and Education Organization. In general, there are several environmental factors related to the growth and decline of harmful algal blooms, including biological factors such as predators and algae-killing organisms, chemical factors such as nutrients, and physical factors such as light, temperature, salinity, and wind accumulation (Fig. 1), but I have been studying the effects of predators. For example, I have found that feeding by species such as the Yakouchu (Noctiluca scintillans), a heterotrophic dinoflagellate (Fig. 2), has the potential to affect the decline of diatoms and harmful algal blooms and prevent them from becoming denser.
In the project for the Grant in Aid for Young Researchers, I would like to elucidate the effects of nutrients on the growth of harmful algae blooms. In recent years, damage to farmed tuna by harmful algal blooms has become a problem, and in many cases, the species responsible for these toxic red tides is Karenia mikimotoi, which is classified as a dinoflagellate (Fig. 2). Karenia mikimotoi descends a few tens of meters at night due to its swimming motion and is thought to use nutrients from the seafloor as well as the water of tuna farms, but quantitative studies have not been conducted. In addition to dissolved inorganic nutrients, it is also known that this species uses dissolved organic nitrogen and phosphorus for its growth, but these have not been monitored. In this study, I have chosen Saiki Bay, Oita Prefecture, as a model sea area to investigate the behavior of dissolved organic nitrogen and phosphorus in seawater at a tuna fish farm and other fixed points. This will provide the basic data for evaluating the relationship between tuna farms and the occurrence of the Carenia Red Tide, and we hope to clarify the material cycle at tuna farms in the future.