Hydrodynamics of pollutant and organic carbon settling: implications for dispersal and concentration in oceans

Understanding the transport, deposition, and burial processes of anthropogenic pollutants (e.g. micro- and nanoplastics), and organic carbon, are major challenges to predicting marine pollution hotspots and quantifying blue carbon stocks.

Burial of particulate terrestrial organic carbon in marine sediments removes CO2 from the atmosphere, which helps to regulating climate over geologic time scales.

Spatial and temporal variability in deposition means that quantification of these blue carbon stocks remain highly uncertain.

Burial efficiency of organic carbon depends on the exposure time to oxygen, which is tied to suspension settling rates that remain poorly constrained.

Similarly, the hydrodynamics and settling rates of microplastic particles, which range in shape and composition, have not been studied.

Sea surface accumulations of plastics account for ~1% of the estimated global marine plastic budget, and the remaining 99% ends up in the deep seafloor. Much of this material occurs as microplastics: small (