Distribution of Hydrocorals Along the George V Slope, East Antarctica

The George V margin is located in east Antarctica, in the region of the Mertz Glacier Tongue. The continental shelf break along this part of the margin occurs at an average depth of 500 m, extending to the abyssal plain below 3,500 m. Three main factors governing their distribution on this margin have been proposed: their depth in relation to iceberg scouring, the flow of organic-rich bottom waters, and their location at the head of shelf-cutting canyons. Icebergs scour to depths of 500 m in this region, and the lack of such disturbance is a likely factor allowing the growth of rich benthic ecosystems. In addition, the richest communities are found in the heads of canyons that receive descending plumes of Antarctic bottom water formed on the George V shelf, which could entrain abundant food for the benthos. The canyons harboring rich benthos are also those that cut the shelf break. Such canyons are known sites of high productivity in other areas due to strong current flow and increased mixing with shelf waters, and the abrupt, complex topography.