Unravelling spatio-temporal patterns of suspended microplastic concentration in the Natura 2000 Guadalquivir estuary (SW Spain): Observations and model simulations Bermúdez Pita, María Díez Minguito, Manuel Plastic pollution Microplastics Transport mechanisms Observations Idealized model Estuary This research is funded by Spanish Ministry of Science, Innovation and Universities (AEI/FEDER/UE) through the projects CTM201677106-R and CTM2017-89531-R. Guadalquivir-LTER project was supported by IFAPA Research Projects PP.FEM.PPA201700.5 and PP.FEM. PP201900.5, 75% cofounded by European Maritime and Fisheries Fund (2014-2022), within the Spanish Operational Program "Fisheries and Maritime 2014-2020". MB and DGF acknowledge funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie, grant agreements 754446 (UGR Research and Knowledge Transfer Fund -Athenea3i) and 846843 (LitRivus), respectively. University of Granada/CBUA provided the funding for open access charges. Finally, the authors would like to thank the two anonymous reviewers and Editor for their valuable comments and suggestions. Microplastics (MPs) patterns in a weakly-stratified estuary were investigated using a combined approach of observations and modeling. The study was conducted in the Guadalquivir River Estuary, which is of high environmental value, yet significantly altered by human activities. The study aims to contribute to understanding and quantifying the land-ocean transport of MPs. Mean concentrations of MPs in the estuary were 0.041 items m(-3), with maximum values up to 0.20 items m(- 3), in agreement with the range reported in other estuaries. Polyethylene floating MPs were predominant. Relationships between increases in MP concentration and local rainfall events were identified in the middle estuary when there were no significant discharges from the head dam. Modeling results mimicked observations and revealed the effects of tidal straining, density-driven, and river flow-induced circulation on the net transport. Convergence of transports favors the MPs trapping in the vicinity of Don tilde ana National Park, overlapping the location of the Estuarine Turbidity Maximum. 2021-10-04T08:36:08Z 2021-10-04T08:36:08Z 2021-09 info:eu-repo/semantics/article M. Bermúdez et al. Unravelling spatio-temporal patterns of suspended microplastic concentration in the Natura 2000 Guadalquivir estuary (SW Spain): Observations and model simulations. Marine Pollution Bulletin 170 (2021) 112622 [https://doi.org/10.1016/j.marpolbul.2021.112622] http://hdl.handle.net/10481/70604 10.1016/j.marpolbul.2021.112622 eng info:eu-repo/grantAgreement/EC/H2020/754446 info:eu-repo/grantAgreement/EC/H2020/846843 http://creativecommons.org/licenses/by-nc-nd/3.0/es/ info:eu-repo/semantics/openAccess Atribución-NoComercial-SinDerivadas 3.0 España Elsevier