2026-07-10 名古屋大学
＜関連情報＞
- https://www.nagoya-u.ac.jp/researchinfo/result/2026/07/post-1034.html
- https://www.sciencedirect.com/science/article/pii/S0025326X26008386
生物付着群集、安定同位体、および漂流モデリングを用いたボトルキャップ漂流のマルチプロキシ再構築 Multi-proxy reconstruction of bottle-cap rafting using biofouling communities, stable isotopes and drift modeling
Naoto Jimi, Naoki Saito, Akito Ogawa, Hiroki Kise, Natsumi Hookabe, Toyoho Ishimura, Masashi Tsuchiya
Marine Pollution Bulletin Available online: 7 July 2026
DOI:https://doi.org/10.1016/j.marpolbul.2026.120051
Highlights
- A bottle cap formed a small raft hosting nine marine groups and 308 individuals.
- A tube-building worm created a three-dimensional habitat inside the drifting cap.
- Oxygen and carbon isotopes in benthic foraminifera recorded changing waters.
- Isotope temperatures cooled to match local sea-surface temperature at collection.
- Ocean-current drift simulations suggest transport from the Philippines via Kuroshio.
Abstract
Floating plastic debris can provide long-lived substrates for attached organisms, but reconstructing the drift history of small consumer items remains difficult. Here we report a colonized plastic bottle cap collected in the northwest Pacific. The cap hosted a tube-building polychaete and an associated assemblage including benthic foraminifera. We combined (1) a census of the fouling community, (2) chamber-level δ18O and δ13C measurements from two Rosalina globularis tests, and (3) Lagrangian drift simulations driven by surface currents to constrain the cap’s likely trajectory and timescale. The assemblage comprised nine taxa and 307 individuals, and was strongly dominated by spirorbid tubes (Spirorbis sp.; 76.5%). For specimen #021, δ18O-derived temperatures were 26.0 °C for the pooled early chambers (p–f-4), 26.8 °C for f-3, 29.9 °C for f-2, 23.3 °C for f-1, and 22.3 °C for the final chamber; the final-chamber estimate was close to the in situ sea-surface temperature at collection (21.7–21.8 °C). The final chamber of specimen #005 yielded an estimated temperature of 27.0 °C but should be treated as a reference value because of its very small carbonate mass. Drift simulations suggested that trajectories reaching the sampling site within ∼1–3 months most frequently originated from the Philippine region and were transported northward by the Kuroshio system. This multi-proxy approach illustrates how benthic biofoulers, including foraminifera, can help reconstruct the dispersal history of small plastic items and highlights the potential for occasional long-distance transport of coastal benthic taxa on tiny rafts.
