The Impact of the Great East Japan Earthquake on Tidal Flat Ecosystems, as Revealed by Nearly 20 Years of Field Research
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The Impact of the Great East Japan Earthquake on Tidal Flat Ecosystems, as Revealed by Nearly 20 Years of Field Research
The massive tsunami triggered by the Great East Japan Earthquake caused extensive damage across a wide area of the Tohoku coast. A joint research team led by Professor Osamu Miura of the Department of Interdisciplinary Sciences, Faculty of Integrated Sciences, Kochi University ( Faculty), in collaboration with Nihon University, the Atmosphere and Ocean Research Institute at the University of Tokyo, and the National Institute for Environmental Studies, investigated the long-term effects of the tsunami on intertidal zone organisms using field surveys and public databases.The results showed that while the tsunami’s impact on birds visiting the tidal flats was limited, benthic organisms such as mollusks, crustaceans, and polychaetes suffered severe damage and took nearly 10 years to recover to pre-tsunami levels. Furthermore, it was revealed that parasites that infect multiple species of benthic organisms and birds require an even longer time to recover.Parasites with life cycles that involve moving between multiple host species cannot maintain stable populations without the recovery of their host communities. Therefore, they are vulnerable to environmental changes caused by disasters, and it is likely that a long period will be required for their recovery. These findings are expected to aid in predicting the impacts on coastal ecosystems and the recovery process following the Nankai Trough earthquake and accompanying tsunami, which are feared to occur in the near future.
This study is the first in the world to conduct a long-term investigation into the effects of tsunamis on tidal flat ecosystems, including parasites. The findings were published in the online edition of *Philosophical Transactions of the Royal Society B*, an international scientific journal published by the Royal Society, on March 5, 2026.
[Research Grants]
This research was made possible through continuous support from Grants-in-Aid for Scientific Research (25840160, 16K18606, 17K07580, 20K06819), the Inamori Foundation, the Ito Science Foundation, the Ministry of Education, Culture, Sports, Science and Technology’s Tohoku Marine Science Hub Initiative, and the Comprehensive Promotion Fund for Environmental Research (JPMEERF24S12320).In addition, during the field surveys, we received the cooperation of many benthic researchers and members of the Miyagi Prefecture Fisheries Cooperative. We would like to take this opportunity to express our sincere gratitude to them.
[Publication Information]
Journal Title: Philosophical Transactions of the Royal Society B
Title of Thesis: The Long-Term Effects of the Tsunamis Caused by the Great East Japan Earthquake on an Intertidal Host-Parasite System.
Authors: Miura, O., Nakai, S., Itoh, H., Kanaya, G. (2026)
DOI: 381: 20240325.
URL: https://doi.org/10.1098/rstb.2024.0325