Benthic Assemblages of the Powell Basin

—During 79th cruise of R/V Akademik Mstislav Keldysh twelve trawl hauls were collected in Powell Basin and adjacent area at depths 370–3771 m. The structure of the benthic assemblages was highly variable when considered at the macrotaxon level. The main factors shaping the taxonomical structure of the sampled assemblages were depth, near-bottom current velocities and proportion of the hard fraction of the sediment. Hard substrate assemblages of the Antarctic peninsula slope and Philip Ridge with high percentage of filter-feeders (mainly sponges) were associated with the highest values of the near-bottom tide currents (up to 55.6 cm/s). In several trawl hauls indicator species of vulnerable marine ecosystems—mainly Demospongiae sponges, deep-sea corals Stylasteridae (Hydrozoa) and Primnoidae (Octocorallia)—were collected.