Spatial patterns and diversity of bryozoan communities from the Southern Ocean: South Shetland Islands, Bouvet Island and Eastern Weddell Sea

In this study, we report new data on the biodiversity and the geographic and bathymetric distribution of bryozoans collected during the ANT XXI/2 cruise (November 2003 to January 2004) in the Eastern Weddell Sea and Bouvet Island, and during the Spanish Antarctic expedition ECOQUIM (January 2006) in the South Shetland Islands. Our data on distribution were analysed together with previous studies carried out in the same regions. A total of 54 species of Antarctic bryozoans (206 samples), including a new species of the genus Reteporella were found. Two species were reported for the first time from Bouvet Island, one from the Weddell Sea and one from Spiess Seamount. Fifty-five per cent of all species identified were endemic to Antarctica. In the Weddell Sea, the regions of Austasen and Kapp Norvegia exhibit the highest relative species richness, followed by the Vestkapp region. Multivariate and cluster analyses revealed small-scale spatial variability in the community structure along depth and between localities.