SHALLOW RHODOLITH BEDS IN CAPO PELORO LAGOON

Abstract

Rhodoliths, unattached benthic calcareous algae, are relevant component of marine coastal environments, mainly in the Circalittoral, where they act both as primary producers and habitat forming organisms. Conversely, shallow water rhodolith beds are poorly characterized, even less in brackish environments. In Capo Peloro Lagoon (north-eastern Sicily), rhodolith beds widely occur both in Lake Faro and the canals connecting to the sea. In the latters, currents hamper mud sedimentation, improve water exchange, supply nutrients and reduce light intensity. In Lake Faro, mud sedimentation is mainly hampered by the anthropogenic disturbance caused by traditional practices of clam farming, which also provide deposits of bioclasts constituting the rhodolith accretion core. By systematic underwater visual surveys rhodolith beds were identified, georeferenced and characterized on a morphological basis. The most common Corallinaceae species, Neogoniolithon brassica-florida, Neogoniolithon hauckii and Phymatolithon lenormandii, revealed to be major actors in the lake-floor stabilization and habitat structuration, further than underline close relationships with long-time persistent human activities.