Local scale high frequency monitoring of seaweed strandings along an intertidal shore of the English Channel (Luc-sur-Mer, Normandy France) – Effect of biotic and abiotic factors
Résumé
Seaweed strandings on Luc-sur-Mer beach (Bay of Seine, English Channel, France) were monitored from March2017 to October 2018 once or twice a week to investigate the wrack deposit dynamics linked to biotic andenvironmental parameters. The extent of stranded seaweed, algal biomass and composition of algal wrack weremonitored through 99 field surveys. Forty-seven macroalgae taxa (14 Phaeophyta, 28 Rhodophyta, and 5Chlorophyta) were identified in strandings. Almost 83% of the 35 taxa (8 Phaeophyta, 23 Rhodophyta, and 4Chlorophyta) inventoried on the nearby intertidal rocky shore during the same period were also identified in thewrack deposits, suggesting their local origin. Analysis of wrack composition revealed the dominance of sheet-likespecies and annual algae mainly represented by Ulva in spring and summer, and by perennial and brown sea-weeds in winter. The same stranding dynamics was observed in the two years with largest deposits in spring andsummer but strandings occurred earlier in 2017, due to contrasted environmental parameters in the two years.Large wrack deposits (> 4.5 Ha) were mainly observed in spring when the wind speed was greater than 2.6 m.s
| Origine | Fichiers produits par l'(les) auteur(s) |
|---|---|
| Licence |
