Comparison of epiphytic diatom communities on Padina pavonica during blue Haslea blooms in the Ligurian Sea and the Adriatic Sea

摘要: Diatom communities are important environmental markers, thus knowing their diversity is essential for a better understanding of the biotope dynamics. Benthic diatoms are one of the first components in costal trophic chains and they play a key role in nutrient cycles and sedimentary flux, however, they remain poorly investigated. For instance, little is known about the epiphytic communities on Padina pavonica, a representative macroalgae in the Mediterranean submarine costal landscape. 1 As for many other microphytic communities, biotic and abiotic parameters structure diatom assemblages. 2 P. pavonica is a yearly species so its epiphytic community should mainly be impacted by the current year environmental parameters. In the frame of the H2020 GHaNA (The Genus Haslea, New marine resources for blue biotechnology and Aquaculture) program, this research project aims to study the development of blue Haslea blooms in some natural environments. Here, we analysed the changes in diatom communities developing on P. pavonica during blue Haslea spp. bloom. We investigated two sites of the Mediterranean Sea, the Ligurian Sea (Calvi, Corsica) and the Adriatic Sea (Dalmatia area). Blue Haslea species are pennate diatoms able to synthetize a blue-green water-soluble pigment, like marennine produced by H. ostrearia species. These marennine-like pigments have allelopathic, antioxidant, antiviral and antibacterial properties, as demonstrated in laboratory conditions. 3–5 Benthic blooms of blue Haslea spp. occur regularly in natural environments (eg, France, USA, Croatia, Australia). For instance, in Calvi Bay,(Corsica France …