Japan Geoscience Union Meeting 2025

Presentation information

[E] Poster

M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

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

Mon. May 26, 2025 5:15 PM - 7:15 PM Poster Hall (Exhibition Hall 7&8, Makuhari Messe)

convener:Haodong Xu(The University of Tokyo), Tahira Irfan(Research Institute for Applied Mechanics, Kyushu University), Chisa Higuchi(Research Institute for Applied Mechanics, Kyushu University ), Atsuhiko Isobe(Kyushu University, Research Institute for Applied Mechanics)


5:15 PM - 7:15 PM

[MIS02-P01] Analysis of long-term variation and “regime shift” in microplastics

*Chisa Higuchi1, Atsuhiko Isobe1 (1.Research Institute for Applied Mechanics, Kyushu University )

Keywords:Microplastics, Long-term variations, AOMI database

BACKGROUND
Marine plastics have attracted worldwide attention as an emerging source of pollution in the marine environment. In particular, much remains unknown about their distribution by region and the drivers of temporal variability. In this study, we performed a long-term variability analysis of microplastics observed in the Pacific and Atlantic Ocean from 2000 to 2018 using The Atlas of Ocean MIcroplastics (AOMI) database.

METHOD OF ANALYSIS
The Pacific and Atlantic Ocean were divided into five areas (Eastern North Pacific, Western, Eastern North Atlantic, Western North Atlantic, and Mediterranean) and their respective microplastic particle densities (pcs/km2) were plotted from 2000 to 2018; after excluding outliers using the 3-sigma method, normalized by the average particle density for the entire period and compared to the global plastic production (Geyer et al., 2017).

RESULTS
As shown in Figure 1, a sharp increase in microplastics was observed around 2009. The increase was particularly pronounced in the North Pacific, suggesting that a regime shift may have occurred during this period. In order to clarify the cause of the increase, comparative analysis with the Pacific Decadal Oscillation (PDO) and North Atlantic Oscillation (NAO) index and particle tracking models is underway. Detailed results will be reported on the same day.