The Bay of Biscay as a trapping zone for exogenous plastics of different sizes

The near-surface transport of exogenous plastics that enter the Bay of Biscay near Cape Ortegal (NW Spain), the main coastal entrance of marine litter into this semi-enclosed sea, were analyzed using a particle tracking model over the period 2009-2018. Four wind drag coefficients were considered to account for the different windages due to the diverse sizes of marine litter. The combined effect of winds and currents results in a higher concentration of floating plastics nearshore favoring beaching. On the other hand, the movement of the smallest plastics (< 5 mm) is only due to the effect of currents which favors their oceanward spread, hindering their further recovery.