[M-IS02] Ocean plastics, an earth science perspective

[MIS02-P04] Distribution Patterns and Characteristics of Plastic Debris Along the Sanriku Coast in Japan

*Batdulam Battulga^1,2, Toyonobu Fujii^1,3, Mironu Ikeda^1,3, Takeshi Obayashi^1,2 (1.Advanced Institute for Marine Ecosystem Change (WPI-AIMEC), Tohoku University, Sendai, Miyagi, 980-8578, Japan, 2.Graduate School of Information Sciences, Tohoku University, Sendai, Miyagi, 980-8578, Japan, 3.Onagawa Field Center, Graduate School of Agricultural Science, Tohoku University, Onagawa, Miyagi 986-2248, Japan)

Plastic debris is a significant environmental issue affecting both local ecosystems and fisheries. While fully understanding its impacts remains challenging, analyzing the distribution patterns and characteristics of plastics provides valuable insights into their sources and potential ecological consequences. This study investigates the distribution and properties of plastic debris along the Sanriku coast of Japan, an ecologically important region and key fishing ground. Plastic and coastal sand samples were collected from four beaches to assess the composition and potential origins of plastics. A variety of plastic debris was observed, with notable differences in distribution patterns and material characteristics among the sites. Despite Sanriku’s importance as a fishing area, many resin pellets and agricultural plastic fragments were found in addition to foam plastics, suggesting that plastic debris in the region originates from both marine and terrestrial sources. The presence of foam plastics aligns with their extensive use in fishing gear and floating equipment. The Sanriku coastal region is strongly influenced by the convergence of the Kuroshio and Oyashio currents, which play a crucial role in the transport, accumulation, and degradation of plastic debris. These currents likely contribute to the observed distribution patterns and the varying properties of plastics found in the collected samples. Although distribution patterns and material properties alone do not fully determine the origins of plastic debris, this study serves as a preliminary step in understanding plastic debris in coastal fishing areas. The findings contribute to the development of improved mitigation strategies for plastic debris in ecologically and economically significant regions.

Keywords: plastic debris, distribution, microplastics, biofilm, ocean currents, Kuroshio, Oyashio, Sanriku coast, Pacific Ocean