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

[AHW27-P08] Microbial Communities on Microplastics from the Tuul River System, Mongolia

*Batdulam Battulga^1,2, Masataka Nakayama^1,3, Dolgormaa Munkhbat⁴, Mariko Atarashi-Andoh¹, Jun Koarashi¹, Mayayuki Kawahigashi⁴ (1.Nuclear Science and Engineering Center, Japan Atomic Energy Agency, Ibaraki, 319-1195, Japan, 2.Advanced Institute for Marine Ecosystem Change (WPI-AIMEC), Tohoku University, Sendai, Miyagi, 980-8578, Japan, 3.Arid Land Research Center, Tottori University, Tottori, 680-0001, Japan, 4.Department of Geography, Graduate School of Urban Environmental Science, Tokyo Metropolitan University, Tokyo, 192-0397, Japan )

Plastic pollution in inland river systems is a growing environmental issue, particularly with the accumulation of microplastics (MPs, <5 mm). While microbial communities play a significant role in the formation of biofilms on MPs, their impact on the properties and persistence of plastic debris in aquatic ecosystems is not well understood. This study investigates the microbial communities associated with MPs collected from the Tuul River and its tributaries in Mongolia, focusing on microbial ecology and its influence on plastic characteristics. In this study, we selected nine sampling sites along the Tuul River and its tributaries (Uliastai, Selbe, and Dund) in Ulaanbaatar City to monitor plastic debris in the inland river system of Mongolia. Then, we analyzed for microbial communities using amplicon sequencing of 16S and internal transcribed spacer (ITS) genes to profile bacterial and fungal diversity in MPs (fibers, films, foams, and fragments), river water, and bottom sediment samples. Differences in microbial composition and diversity were observed between MPs and environmental compartments (water and sediment). In addition, the Tuul River and its tributaries showed distinct patterns of bacterial and fungal communities. This study emphasizes the role of microbial functions in the plastisphere, providing insights into how biofilms affect the fate of plastic debris in the Tuul River system and other inland aquatic environments.

Keywords: microbial taxa, potential pathogenic species, microplastic, floodplain