Before the deployment the cups were cleaned with 0.5 N HCl, rinsed with ultrapure water and filled with buffered 5% (v/v) formaldehyde solution in 0.45 μm filtered seawater. This poisoning solution prevents degradation of trapped particles and limits the disruption of swimming organisms (“swimmers”) that occasionally enter the traps during sampling. After recovery, the closed cups were stored in the dark at 2–4 °C until they I-BET151 could be processed in the laboratory, within a maximum delay of a few weeks. After decantation of the supernatant, particles were wet-sieved through a 1 mm nylon mesh to retain the largest swimmers, while the smaller ones were removed under a dissecting microscope using fine tweezers. The sample was then divided into 3 equal wet aliquots for PFAS, grain size, and organic carbon (OC) analyses using a larynx rotary splitting method. Subsampling uncertainty was of 4.1% (Heussner et al., 1990).
Measurements of significant wave height were obtained from the Datawell directional buoy 06601 (located at 50 m of water depth and 1 mile off Banyuls, Fig. 1) of the French network CANDHIS operated by the Centre d\'Etudes Techniques Maritimes et Fluviales (CETMEF). Sensible heat fluxes in the Gulf of Lion shelf were obtained through the Giovanni online data system, developed and maintained by the NASA GES DISC, as described in Acker and Leptoukh (2007).