SEAVE – Seaweeds of Venice lagoon: a Barcode of Life data system project revealing hidden macroalgal diversity

The biodiversity concept involves the knowledge of the variety of life that can be studied at genetic level, species and ecosystem levels, both on time and spatial scales. To avoid underestimating and/or overestimating the biodiversity of an area, a correct identification of species is essential. DNA barcoding is considered the preferred approach in this task, for species identification and to monitor the biodiversity a highly productive biological areas like coastal lagoons, which play an important ecological role by providing a mosaic of habitats for economically important species. DNA barcoding is an appealing tool for biodiversity investigations, able to identify specimens during all life stages, from fresh or preserved material, and to detect potential cryptic species, which are very common among macroalgae. Within the Mediterranean transitional environments, Venice Lagoon is a peculiar environment, with both high biodiversity and a significant human influence; it is particularly rich in macroalgal species, and numerous reports of discoveries and of new introductions have been published so far. This richness depends both on the peculiar environmental characteristics of the basin and some anthropic activities, such as aquaculture and maritime traffic, which encourage the introduction and dispersal of new species as well as the decrease and/or removal of the native flora. At present, only a few studies of molecular systematics focus on the macrophytes of Venice Lagoon, dealing with specific taxa (1-4), while a checklist based on molecular methods is still sorely missing.Within the program of census of marine flora of Italian coastal lagoons (5), we are aiming to compile a DNA barcode inventory and eventually a taxonomic revision of most critical taxa occurring on hard substrata of the historical centre of Venice and surrounding islands. Inside this framework, we present new molecular data obtained for Ulvacean samples and for cryptic taxa of the Bangiales and Ceramiales, including alien species