FN Archimer Export Format
PT J
TI Bottom trawling contribution to the spatio-temporal variability of sediment fluxes on the continental shelf of the Bay of Biscay (France)
BT 
AF Mengual, Baptiste
   Le Hir, Pierre
   Cayocca, Florence
   Garlan, T.
AS 1:1;2:1;3:1,2;4:3;
FF 1:PDG-ODE-DYNECO-DHYSED;2:PDG-ODE-DYNECO-DHYSED;3:PDG-ODE;4:;
C1 IFREMER-DYNECO/DHYSED, centre de Bretagne, ZI de la Pointe du Diable CS 10070, 29280 Plouzané, France
   AAMP (Agence des Aires Marines Protégées), 16 Quai de la Douane, 29200 Brest, France
   SHOM/DOPS/HOM/Sédimentologie, 13 rue du Châtellier, CS 92803, 29228 Brest Cedex 02, France
C2 IFREMER, FRANCE
   AGENCE AIRES MARINES PROTEGEES, FRANCE
   SHOM, FRANCE
SI BREST
SE PDG-ODE-DYNECO-DHYSED
   PDG-ODE
IN WOS Ifremer UPR
   copubli-france
IF 3.04
TC 12
UR https://archimer.ifremer.fr/doc/00500/61146/64574.pdf
LA English
DT Article
DE ;Sediment fluxes;Bottom trawling;Numerical modelling;Bay of Biscay;Continental shelf
AB Based on experiments, a trawling-induced erosion dynamics was included in a 3D realistic and pre-validated hydro-sedimentary model so as to assess its contribution to the overall regional sediment dynamics in the specific case of the Bay of Biscay continental shelf. The effect of trawling was investigated throughout a 5-year period in terms of horizontal/vertical fluxes and changes in seabed mud content, and compared to the natural variability of sediment fluxes at different spatio-temporal scales. Trawling is shown in the model to significantly contribute to sediment re-suspension, and changes in the seabed at the scale of the shelf. The contribution of trawling to re-suspension is >80% during the high fishing season at many locations on the outer shelf and over the Grande-Vasière area (a large and intensively trawled muddy zone located in the middle of the shelf). The contribution of trawling is significantly weaker in winter and at annual scale, particularly over zones with (muddy-) sand facies (between 1‰ and 1%), but remains high, and reaches 20% of the annual erosion over muddy areas (e.g. northern part of the Grande-Vasière). This significant trawling-induced erosion dynamics results in high sediment fluxes which increase natural poleward dynamics from a few percent up to 40%, and contributes to the natural offshore export of sediment on the outer shelf (e.g. +35% of mud fluxes along the 130 m isobath). It is noteworthy that trawling-induced fluxes are larger in winter although the corresponding re-suspension is lower than in summer: this is due to stronger near-bottom flows occurring at this period (largely influenced by energetic wind conditions). In contrast, on the inner shelf, trawling-induced sediment fluxes are rather oriented towards the coast. Finally, simulation results reveal a trawling signature on changes in the seabed. A significant decrease (between 10% and >50%) in mud content is simulated over trawling hotspots, especially over the internal part of the Grande-Vasière and on mud patches located in front of the Gironde estuary. Conversely, trawling causes or intensifies mud deposition on both sides of these preferentially trawled areas. 
PY 2019
PD AUG
SO Marine Geology
SN 0025-3227
PU Elsevier BV
VL 414
UT 000474325700006
BP 77
EP 91
DI 10.1016/j.margeo.2019.05.009
ID 61146
ER

EF