Thursday, May 18, 2017 – 13:30, room U7-06, Building U7
Mario De Stefano, Università degli Studi della Campania “Luigi Vanvitelli” (Seconda Università di Napoli)
In polar and tropical regions, the rates of primary production of the microalgal communities associated with macroalgae, seagrasses and marine invertebrates are comparable or sometimes higher to those of the phytoplankton component. These benthic microalgal communities, which are mainly represented by diatoms, appear to be composed by a limited number of genera, belonging to different growth forms that can be considered fully adapted to the epibenthic lifestyle. In spite of the important ecological role played in the food chain, the biodiversity of epibenthic diatom communities worldwide is still poorly studied and highly underestimated. Moreover, ecological studies on epibenthic diatom communities based on a rigorous taxonomic approach are rare due to the small size of such organisms. Indeed, most of the species have average size less than 20 microns with taxonomic characters not resolvable in light microscopy, so the scanning electron microscopy results the only possible approach for a correct quantitative analysis of such floristic communities. International collaborations, that are destined to continue in the coming years, have been institutionalized within of a multi-year project, which has the purpose to describe the biodiversity and the community structure at genus and/or species level of epibenthic diatoms on different host species (macroalgae, seagrasses, invertebrates, vertebrates) from Polar (Antarctica and Arctic) Mediterranean and tropical Regions. Until now, epiphytic diatoms living on different macroalgae were collected and analyzed from coastal areas of the Antarctic Italian Base “Mario Zucchelli” (Terranova Bay, Ross Sea, Austral Summer 2012, 2013) and four Antarctic foreign research stations: the American base “McMurdo” (McMurdo Sound, Ross Sea, AS 2009/10), the Polish base “H. Arctowski”, the Brazilian base “Comandante Ferraz” and the Chilean “Escudero” (King George Island, South Shetlands, AS 2010/11, 2014, 2015). In tropical areas epibenthic diatom assemblages on seagrasses (Posidonia spp.), on hydrozoans, gastropods, crustaceans and recently marine turtles have been collected. In this presentation an overview of the results of a four-year study on the ecological role of epibenthic diatom communities on Antarctic macroalgae and on tropical species of marine turtles will be given.
Host: Davide Seveso