A.-E. Paquier, S. Meulé, E.J. Anthony, G. Bernard, 2014. Sedimentation and erosion patterns in a low shoot-density Zostera noltii meadow in the fetch-limited Berre Lagoon, Mediterranean France. In: Green, A.N. and Cooper, J.A.G. (eds.), Proceedings 13th International Coastal Symposium (Durban, South Africa), Journal of Coastal Research, Special Issue No. 70, pp. 563–567, ISSN 0749-0208
Seagrass meadows fulfill several coastal ecosystem services that include coastal protection, provision of shelter for fishes and fish nesting sites, and water oxygenation. These aspects are hinged in part on the capacity of these meadows to attenuate waves and to slow down currents. Berre lagoon (area: 155 km²) is a fetch-limited, micro-tidal brackish water body on the French Mediterranean coast. At the turn of the 20th century, the lagoon was occupied by extensive meadows of Zostera marina and Zostera noltii. Urban and industrial pollution and freshwater diversion into the lagoon contributed to the complete disappearance of Zostera marina while Zostera noltii declined dramatically. Since the 1970s, these sources of perturbation have been drastically reduced but with no appreciable effect on Zostera noltii. A study was carried out on a receding Zostera noltii meadow occupying a small shallow bay (< 2 m deep) fronting a beach over a 14-month period in order to monitor both patterns of shoot density and erosion and accretion in the bay. Berre lagoon experiences short-fetch waves generated by northwesterly “Mistral” winds that exhibit a seasonal pattern. Shoot density shows a markedly seasonal trend that does not appear to be related to bed changes, which evened out over the study period. The data show that bed changes are less marked over the Zostera noltii meadow, and are more important in non-colonized areas, as well as along the beach, which exhibits sediment rotation. These patterns are probably reflecting the influence of the meadow on wave dissipation patterns.