Copepods, hydromedusae and siphonophores: Diversity and distribution in the Gerlache Strait, Antarctic Peninsula

摘要

Project Biodiversity and oceanographic conditions of the strait of Gerlache "Biogerlache-Antarctica", aims to carry out the characterization of the Antarctic fauna of the strait, generating new contributions to the biological inventories of Antarctica. Present work focuses on the biodiversity of the zooplanktonic community, specifically on copepods, hydromedusae and siphonophorae collected during the Ⅲ Antarctic Expedition of Colombia "Admiral Padilla" (2016-2017). Sampling was carried out in seven oceanographic stations located along the Gerlache strait, with vertical trawls between the maximum depth of the station and the surface. 4100 organisms belonging to 38 species of the phylum Arthropoda (Orders Calanoid and Cyclopoid) and 10 species of the phylum Cnidaria (Subclasses Hydroidolina and Trachylina) were identified. Copepods families with the greatest richness of genera are Aetideidae and Metridinidae, with Met-ridia gerlachei, Chiridius polaris and Gaetanus tenuispinosus being frequent species in more than 50 % of the stations. Identified species are common to the Antarctic Peninsula (Bellingshausen Sea, Scotia Sea and the Weddell Sea), also the range of four copepods are extended for the epipelagic and mesopelagic waters of the Gerlache Strait. Other frequent species are the hydromedusae Arctapodema sp. and Solmundella bitentaculata and the siphonophores Dimophyes arctica and Diphyes antarctica, the latter being collected in both polygastric and eudoxic forms (the dominant form in all stations).