Japan Geoscience Union Meeting 2025

Presentation information

[E] Oral

A (Atmospheric and Hydrospheric Sciences ) » A-HW Hydrology & Water Environment

[A-HW27] Biodiversity, nutrients and other materials in ecosystems from headwaters to coasts

Thu. May 29, 2025 1:45 PM - 3:15 PM Exhibition Hall Special Setting (2) (Exhibition Hall 7&8, Makuhari Messe)

convener:Noboru Okuda(Kobe University), Takuya Ishida(Hiroshima University), Masahiro Kobayashi(Kansai Research Center, Forestry and Forest Products Research Institute), Adina Paytan(University of California Santa Cruz), Chairperson:Takuya Ishida(Hiroshima University)


3:00 PM - 3:15 PM

[AHW27-18] Sediment eDNA Metabarcoding Reveals Fish and Benthic Metazoan Diversity in a Tidal Flat of Seto Inland Sea, western Japan

*Nhat Hong Nguyen1, Mitsuyo Saito2, Shin-ichi Onodera2, Mayuko Hamada3 (1.Faculty of Technology-Engineering-Environment, An Giang University, VNU-HCM, Viet Nam, 2.Graduate School of Advanced Science and Engineering, Hiroshima University, Hiroshima, 3.Ushimado Marine Institute (UMI), Graduate School of Environmental, Life, Natural Science and Technology, Okayama University, Okayama)

Keywords:environmental DNA, fish diversity, metazoan diversity, sediment, submarine groundwater discharge

Abstract
Marine biodiversity is increasingly threatened by climate change and anthropogenic disturbances, necessitating robust and efficient monitoring strategies to inform conservation efforts. Environmental DNA (eDNA) metabarcoding has emerged as a powerful tool for assessing biodiversity, offering a non-invasive and comprehensive approach to characterizing ecological communities. This study employs sediment eDNA metabarcoding to investigate fish and benthic metazoan assemblages at a tidal flat of Ikuchijima Island in Seto Inland Sea, providing insights into species composition and community structure. The analysis identified 63 fish species spanning 37 families, reflecting high local ichthyofaunal diversity. In addition, eDNA from seabed sediments detected 41 metazoan families across 10 phyla, underscoring significant benthic biodiversity. Comparative analysis revealed that the western part of the tidal flat (IKH site) harbored a greater number of metazoan families than the eastern part of the tidal flat (IKG site). The IKH site, which experiences higher fresh submarine groundwater discharge (SGD), exhibited a greater diversity of metazoan families compared to the IKG sites. Specifically, polychaete and copepod families were more abundant at IKH, suggesting that SGD plays a critical role in shaping benthic community structure. These findings underscore the utility of sediment eDNA metabarcoding as a non-invasive tool for biodiversity assessment and suggest that SGD may enhance benthic habitat complexity and biodiversity.

Acknowledgments
This research was supported by JSPS Grant-in-Aid for Scientific Research (B) (No. 21H03650, PI: Mitsuyo Saito) and Fostering Joint International Research (A) (No. 20KK0262, PI: Mitsuyo Saito).