Modelling the effects of Zostera noltei meadows on sediment dynamics: application to the Arcachon lagoon

Type Article
Date 2014-10
Language English
Author(s) Kombiadou Katerini1, 2, Ganthy FlorianORCID1, 2, Verney RomaricORCID1, Plus MartinORCID2, Sottolichio Aldo3
Affiliation(s) 1 : IFREMER, DYNECO PHYSED, F-29280 Plouzane, France.
2 : IFREMER, LER AR, F-33120 Quai Commandant Silhouet, Arcachon, France.
3 : Univ Bordeaux, CNRS, UMR EPOC 5805, F-33615 Pessac, France.
Meeting 7th International Conference on Coastal Dynamics in Arcachon, France 24–28 June 2013
Source Ocean Dynamics (1616-7341) (Springer Heidelberg), 2014-10 , Vol. 64 , N. 10 , P. 1499-1516
DOI 10.1007/s10236-014-0754-1
WOS© Times Cited 23
Keyword(s) Zostera noltei, Sedimentation, Erosion, Arcachon lagoon, Intertidal mudflats, Flume measurements
Abstract A three-dimensional model has been modified to describe the complex interactions between hydrodynamics, sediment dynamics and biological parameters in the presence of Zostera noltei. The model treats seagrass leafs as flexible blades that bend under hydrodynamic forcing and alter the local momentum and turbulence fluxes and, therefore, the benthic shear conditions; these changes cause related changes to the mass balance at the boundary of the bed, in turn affecting the suspended matter in the column and ultimately primary productivity and the growth of the dwarf-grass. Modelling parameters related to the impact of Z. noltei to the local flow and to erosion and deposition rates were calibrated using flume experimental measurements; results from the calibration of the model are presented and discussed. The coupled model is applied in the Arcachon Bay, an area with high environmental significance and large abundance of dwarf-grass meadows. In the present paper, results from preliminary applications of the model are presented and discussed; the effectiveness of the coupled model is assessed comparing modelling results with available field measurements of suspended sediment concentrations and seagrass growth parameters. The model generally reproduces sediment dynamics and dwarf-grass seasonal growth in the domain efficiently. Investigations regarding the effects of the vegetation to the near-bed hydrodynamics and to the sediment suspension in the domain show that dwarf-grass meadows play an important part to velocity attenuation and to sediment stabilisation, with flow and suspended sediment concentrations damping, compared to an unvegetated state, to reach 35-50 and 65 %, respectively, at peak seagrass growth.
Full Text
File Pages Size Access
18 2 MB Access on demand
Author's final draft 31 1 MB Open access
Top of the page