SEAGRASS WRACK-INDUCED DUNE FORMATION ON A TROPICAL COAST (BANC-DARGUIN, MAURITANIA)

The Banc d'Arguin (Mauritania) is a shallow water area with mudflats bordering on the Sahara desert. Mass depositions of seagrass litter were observed on some parts of the shore. Soil profiles of the low dune formations separating the flood debris zone from the desert showed that layers of seagrass detritus, in various stages of decay, extended under the dune formations. The tentative mechanism of dune formation, involving the interacting processes of beaching of seagrass litter and wind-blown transport of desert sediment in a seaward direction, is described. This role in dune formation adds a new element to the significance of seagrass vegetation for the coastal environment. © 1990.