Community structure of pelagic cnidarians off Adélie Land, East Antarctica, during austral summer 2008

21 pages, 8 figures, 4 tables

Some studies have suggested that pelagic cnidarians are important components of the Southern Ocean ecosystem due to their high abundance and diversity and their high predatory effects, although little information on these animals is available. Thus, we examined the spatial distribution of pelagic cnidarians from the oceanic to neritic zone off Adélie Land, East Antarctica. Discrete depth sampling was conducted from the surface to 2,000 m depth from late January to early February 2008. In total, 3347 individuals representing 45 species/taxa from eight orders were collected. Cluster analysis revealed three major clusters: (1) an epipelagic group in the oceanic zone composed mainly of Pegantha martagon, the abundance and species diversity of which were very low; (2) a meso- and bathy-pelagic group characterised by high abundance and species diversity with dominance of Dimophyes arctica, Vogtia serrata, and Halicreas minimum; and (3) a neritic group represented by a high abundance of Diphyes antarctica. Cnidarian communities in the epipelagic zone were divided by hydrographic structures such as the Southern Boundary of the Antarctic Circumpolar Current and Antarctic Slope Front, whereas those in the meso- and bathy-pelagic layers dominated by circumpolar deep water were relatively stable with higher diversity throughout the oceanic zone. © 2013 Springer-Verlag Berlin Heidelberg

The survey in 2008 was conducted as a part of the Collaborative East Antarctic Marine Census (CEAMARC) programme. This study was supported by Grants-in-Aid for Scientific Research from the Japan Society for the Promotion of Science (Nos. 14255012 and 19255014 for T. Ishimaru, TUMSAT)

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