Hydroid assemblages from the Bellingshausen Sea (Antarctica): environmental factors behind their spatial distribution

摘要: Although scientific knowledge about the biodiversity of Antarctic benthic hydrozoans has considerably increased in recent years, little is known their spatial distribution and underpinning factors. Trying to contribute filling this gap, hydroid Bellingshausen Sea (Southern Ocean) was studied. Samples were collected at 32 stations depths between 86 3,304 m during Spanish expeditions 2003 2006. Sediments bottom water properties analyzed using an USNEL-type box corer a Neil Brown Instrument System Mark III CTD, respectively. Forty species reported (Acryptolaria sp., Stegopoma plicatile, Staurotheca dichotoma having highest percentages occurrence), representing ca. 19 % richness fauna Southern Ocean. Three well-defined assemblages (shallow, deep transitional) established based on significant differences occurrence. Benthic seems be controlled mainly by depth substrate (most hydrozoan are epibiotic), dispersal abilities resilience changing hydrodynamic conditions. The level found present study, compared with other areas, gives support arguments stated authors against idea that “a benthos desert” oligotrophic conditions intense iceberg traffic.