0
Article ? AI-assigned paper type based on the abstract. Classification may not be perfect — flag errors using the feedback button. Tier 2 ? Original research — experimental, observational, or case-control study. Direct primary evidence. Environmental Sources Human Health Effects Marine & Wildlife Sign in to save

Convergence zones of coastal waters as hotspots for floating microplastic accumulation

Marine Pollution Bulletin 2024 8 citations ? Citation count from OpenAlex, updated daily. May differ slightly from the publisher's own count.
Masatoshi Nakakuni, M Nishida, Ryosuke Nishibata, Koji Kishimoto, Hitomi Yamaguchi, KAZUHIKO ICHIMI, Masahide Ishizuka, Yoshihiro Suenaga, Kuninao Tada

Summary

Researchers measured microplastic concentrations in convergence zones of Japan's Seto Inland Sea, where ocean currents push floating debris together. They found that these zones contained 40 to 300 times more microplastics than surrounding waters, with expanded polystyrene being the most common type. The study identifies coastal convergence zones as significant hotspots for microplastic accumulation that deserve targeted monitoring and cleanup efforts.

Polymers

This study examines microplastic (MP, 1-5 mm) densities in convergence zones in a coastal sea, the Seto Inland Sea, comparing them to those of non-convergence zones and other areas. Notably, Seto convergence zones exhibit MP densities 40 to 300 times higher than non-convergence zones, with an extraordinary density of 3.7 ± 6.3 pieces m-3, similar to densities found in Tokyo Bay as known a MP hotspot. The predominant polymer found was expanded polystyrene, varying seasonally and peaking in summer. Juvenile fish associated with driftweed in these convergence zones face a risk of long-term MP exposure, potentially up to four months. This large number of MPs found in coastal convergence zones is similar to accumulation zones formed in the gyres of open oceans, with strong implications for detrimental effects on coastal marine life. However, these MPs are autochthonous, and may be manageable through local marine plastic waste management.

Share this paper