Microplastics in guano of three Peruvian guano seabird species at Punta Coles, Humboldt Current System

Valeriano-Zapana J.A.; Percca-Mendoza M.A.; Melendez-Mier J.J.; Paccosonco-Sucapuca L.A.; Gonzales Soto H.H.; Álvarez-Tolentino D.; De La Cruz A.H. · Marine Pollution Bulletin (2026) · DOI: 10.1016/j.marpolbul.2026.119349

Resumen

Microplastics (MPs) are increasingly reported in seabird feces, but fecal deposits of Peruvian guano birds remain unexplored. We quantified MPs in feces of three guano-producing seabirds ( Sula variegata , Phalacrocorax bougainvillii , Pelecanus thagus ) at Punta Coles, a guano headland within the Reserva Nacional Sistema de Islas, Islotes y Puntas Guaneras (RNSIIPG), Peru. Fecal samples from 67 sampling points were processed by density separation (NaCl, ~1.2 g cm−3), Fenton oxidation, stereomicroscopy and μ-Raman spectroscopy. MPs were detected in 80.6% of samples ( n = 54 particles), with median abundance 0.20 items g−1 dw (mean 0.16 ± 0.08) and no significant differences between habitat zones (Wild vs. Direct-use; Mann–Whitney U = 534.5, p = 0.985) or among species (Kruskal–Wallis H = 0.772, p = 0.680). Assemblages were dominated by filaments (66.7%), with fragments (29.6%) as secondary contributors and microbeads rare (3.7%). Polyester (PET, 58.0%) was the main polymer, followed by polyamide (PA, 20.0%) and polypropylene (PP, 8.0%); blue and white/grey were the most frequent colours. μ-Raman spectroscopy confirmed 92.6% of analysed particles (50/54). Multivariate analyses (PCA, NMDS, MFA, PERMANOVA) and co-occurrence networks revealed a homogeneous PET–PA–PP filament-dominated assemblage with no detectable compositional differences between zones or species (all R2 ≤ 0.16, p > 0.05). Effect sizes were small ( r ≤ 0.18, η2 ≈ 0), and the detection limit (~40 μm) excluded smaller MPs and nanoplastics. Fecal surveys offer a practical, non-lethal approach to monitor seabird-mediated fluxes of MPs in the Humboldt Current system, with potential applications for long-term surveillance within Peru's marine protected area network. Copyright

Instituciones: Universidad Nacional de Moquegua; Universidad Nacional Intercultural de la Selva Central Juan Santos Atahualpa