Marine Macroalgal Diversity in Admiralty Bay, King George Island, South Shetlands Islands, Antarctica

e Antarctic Continent is undergoing environmental alterations due to global climate changes and anthropic activities. e knowledge of the biodiversity and of the ecophysiology of the organisms in this region is of essential importance to delineate strategies of protection and for the management of such a fragile region of the planet. Among the organisms to be monitored, the macroalgae are an important natural resource. Admiralty Bay, including the Martel inlet, is an Antarctica Special Management Area (ASMA), which undergoes changes during the year due to the coverage of ice creating perturbed climatic conditions, negatively a ecting the macroalgae. Previous studies suggest that Admiralty Bay is an ecotone between the Sub-Antarctic Islands and the coastal zone of Continental Antarctica. is research has the purpose of contributing to the knowledge of the macroalgae clarifying the transitory character of the macroalgal community and its distribution in the bay. From the analysis of the samples of macroalgae collected in the period of December 2010 to February 2011 and from December 2011 to January 2012, it was possible to identify 60 species of algae, of which, 29 Rhodophyta, 14 Chlorophyta and 17 Heterokontophyta. e Ceramiales order (10 species) was the most representative among the Rhodophyta, in that 80% consisted of Delesseriaceae. e presence of Heterokontophyta of large size, such as Himantothallus grandifolius, Phaeurus antarcticus, Ascoseira mirabilis and Cystophaera jacquinotii, and the Rhodophyta, Pyropia endiviifolia and Georgiella con uens con rm the endemic character of these species in Maritime Antarctica and in the Antarctic Peninsula. e Chlorophyta, Blidingia minima, Ulva compressa, U. intestinalis and the Heterokontophyta, Petalonia fascia encountered in Admiralty Bay have wide geographical distribution in both hemispheres. In the southern hemisphere, in the Cabo Frio region, of the State of Rio de Janeiro, these species appear fully developed during the summer, a period marked by the occurrence of phenomenon of upwelling, which con rms the connectivity of the Sub-Antarctic waters with the tropical region of the South Atlantic.