Suchergebnisse

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. ; 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.

The accelerated discard and mismanagement of human-made products are resulting in the continued input of litter into the oceans. Models and field observations show how floating litter can accumulate in remote areas throughout the global ocean, but far less is known about the non-floating litter fraction. Seagrass meadows play an important role in the sediment and natural-debris dynamics, and likely also in the storage and processing of non-floating litter. In this work, non-floating litter was studied across six Posidonia oceanica meadows. Litter accumulated mainly around the landside edge of the meadow. The outer margin of the edge predominantly trapped macro-litter, whilst microplastics accumulated mainly along the inner margin. On average, macro-litter concentrations increased 3-fold after heavy rainfall. Retention of non-floating litter by coastal meadows facilitates the recurrent landward-seaward conveyance of the easily-transportable litter (mainly plastic items) and its fragmentation before it is buried or transferred to deeper areas. ; This work was supported by Ministry of Economy and Competitiveness of the Government of Spain ('MIDaS' CTM2016-77106-R, 2016); University of Cadiz (FPUCA2018, Support for university professors training for doctoral students at the University of Cadiz); CEIMAR Foundation, C´adiz (Grant for international mobility of doctoral students for development of thesis in co-tutelage regime, 2019); 'Diputaci´on de C´adiz' and SEA-EU (Beca Talento, 2021).