Rich ecosystems in coastal zones include tidal flats, seagrass meadows, and coral reefs. Coastal zones are valuable places for the global environment. However, during the era of rapid economic growth, intense socio-economic activities caused the deterioration of water quality in coastal inner bays and enclosed waters, resulting in ecosystem damage. Thanks to subsequent countermeasures, water quality has gradually been improving in some coastal zones; however, recovery of the coastal zone environment including ecosystems remains a formidable challenge.

On the other hand, new challenges include the utilization of coastal zone functions for mitigating climate change, as well as countermeasures against large-scale oil spill incidents from maritime industrial complexes and other facilities.

Therefore, in the themes of this research, we will conduct research and development with the following goals: further restoration of the coastal zone environment, coastal zone utilization for climate change mitigation, and establishment of technologies to counter large-scale oil spill incidents.

As for the study on the global dynamics model for estimating the CO2 absorption rates in shallow sea areas and inundation suppression effects, we developed and tested a global carbon circulation/ecosystem model and a wave and topography model, gathered topographic and ecosystem data for global estimation, and performed GIS analyses of such data. We also conducted in situ surveys and experiments on carbon dynamics in seagrass meadows, and performed analyses using numerical models.

For the creation of coastal topography and geo-design that help both mitigate disasters and preserve ecosystems, we further improved the integrated assessment and prediction method applicable to the coastal ecosystems and geoenvironmental dynamics, elucidated how earthquake-induced soil liquefaction, storms, and waves could impact various types of benthic organisms in intertidal and subtidal zones in terms of how they would be transported, floated, and buried, and also their mortality rates. In addition, we evaluated and analyzed the performance of various geoenvironments, including recycled soil, to resist erosion and be used as a habitat by organisms.

For the research on cross-sectional observation and analysis of atmospheric and oceanographic issues at bay mouths, we monitored wind conditions in the atmosphere and facilitated development of the cross-sectional observation system. In addition, we continued steadily with marine observation activities, examined the feasibility of applying satellite data to bay-mouth monitoring, and conducted on-site observations.

For the dynamic analysis of macro-organisms in coastal ecosystem simulations, we created a code based on the formulation work done during the previous fiscal year, implemented the code in the Ise Bay simulator, organized data gathered during on-site observations related to current quantities, etc., and compared the data to the simulation results.

For the development of technology to improve the functions of ecosystems in seagrass meadows, we obtained data on the fish community by utilizing environmental DNA, for which technical innovation has been advancing in recent years. In addition, we conducted feeding experiments on the fauna inhabiting seagrass meadows and assessed their value as food in order to evaluate the function of seagrass meadows as feeding grounds for fishes.

For the numerical analysis of coastal currents using current simulation and data assimilation, we conducted numerical experiments in rectangular model sea areas, and verified that data assimilation can be done by using a method of adding noise to the boundary conditions to create their ensemble. In addition, we conducted data assimilation using actual water temperature data measured in Tokyo Bay and demonstrated that the water temperatures were corrected so as to approach the measured values.

As for R&D on improving next-generation technology to mitigate oil pollution, we conducted model experiments to explore oil-gathering methods that might be suitable for adoption by next-generation oil recovery equipment, which involved using pressurized water jet suction and an excess water recycling system. In addition, we upgraded the network-adaptive oil movement prediction system to better estimate how marine oil spills are transported by the water. Furthermore, we studied a method of controlling oil spills using self-extracting bubble curtains.