This manuscripts describes the results of an initial experiment that analyzed Stokes drifter's trajectories in the Dutch Wadden Sea, mostly affected by the tidal cycle and wind conditions. It sets a new methodology to automatize the analysis of GPS data in order to determine whether the drifter was moving floating on the water or stopped on the ground (mudflats, beach, etc.).

While the methodology is robust, the Stokes drifters used (1 kg - circular flat shape) may behave quite differently from many of the most common items found floating at sea in shape and floatability, which can be predominantly film type plastic fragments of only a few grams that are inmersed in the upper layer and not exposed to windage, or highly protuding and exposed to windage items like bottles or foam like polymer, again lower weight and different behaviour to wind. This brings the further question of how can different litter items respond to grounding events on the mudflat, given the different shapes and densities (or floatability) compared to the drifter's, could some get stuck (like glued). This is only discussed very briefly.

Another issue is the lack of discussion on the nature of the groundings (or beaching), since other substrates than mudflats may have a high capacity to trap plastics, like vegetated saltmarshes.

In general, the discussion of results is very limited. For example, on how could be defined the awaited specific parameter considering beaching that modelers could use to improve global plastic transport models.

Please find some minor questions/suggestions in the commented PDF file.