The boundary current role on the transport and stranding of floating marine litter: The French Riviera case
|Author(s)||Ourmieres Yann1, Mansui Jeremy1, Molcard Anne1, Galgani Francois2, Poitou Isabelle3|
|Affiliation(s)||1 : Univ Toulon & Var, MIO, IRD, INSU,CNRS,UMR7294,UM 110, F-83957 La Garde, France.
2 : IFREMER, ZI Furiani, Immeuble Agostini, F-20600 Bastia, Corsica, France.
3 : Assoc Mer Terre, 21 Rue Montgrand, F-13006 Marseille, France.
|Source||Continental Shelf Research (0278-4343) (Pergamon-elsevier Science Ltd), 2018-03 , Vol. 155 , P. 11-20|
|WOS© Times Cited||22|
The aim of the present study is to evidence the role of a boundary current and meteorological conditions in the transport and stranding of floating marine debris. The used data are from a beach survey and an inter-annual unique effort of marine debris sightings along the French Riviera in the North-Western Mediterranean region. Offshore data have been collected during oceanic cruises while beach surveys were performed around Antibes city. Debris were found on 97% of the ocean transects, with a large spatial and temporal variability, showing contrasted areas of low (~ 1 item/km2) and of high (> 10 items/km2) debris densities. Results suggest that the debris spatio-temporal distribution is related to the Northern current (NC) dynamics, the regional boundary current, with accumulation patterns in its core and external edge. By playing a role in the alongshore transport, such a boundary current can form a cross-shore transport barrier. Stranding events can then occur after strong on-shore wind bursts modifying the sea surface dynamics and breaking this transport barrier. It is also shown that episodic enhancement of the stranding rate can be explained by combining the NC dynamics with the wind forcing and the rainfall effect via the local river run-off. Conversely, off-shore wind bursts could also free the marine litter from the boundary current and export them towards the open sea.