Marine Science Research

Antarctic Benthic Community Ecology

The benthos on opposite sides of McMurdo Sound (77°45’ S, 165°E) in the Ross Sea differs remarkably in terms of species composition, diversity, and abundance. Along Ross Island on the west side of the sound currents deliver plankton rich waters from the north in the Austral summer. This seasonally abundant food resource feeds the abundant infaunal and epifaunal communities found there. Above 33 meters the epifauna are composed primarily of organisms that can resist disturbance by anchor ice such as sea anemones, or that can grow rapidly between periods of ice disturbance such as the sponge Homaxonella sp. Below 33 m the seafloor is totally covered by sponges and the upper meter of sediments is composed primarily of sponge spicules. Along the Antarctic continent on the east side of ice cover often persists for several years preventing any significant in situ primary production and currents deliver clear water from underneath the Ross Ice Shelf. The highly oligotrophic conditions result in dramatically lower biomass and density of infaunal and epifaunal animals. Photos of the seafloor from depths of 10 to 50 m often resemble photos from the deep-sea from several thousands of meters.

For more information see:

Dayton, P. K., G. A. Robilliard, and A. L. DeVries. (1969). “Anchor ice formation in McMurdo Sound, Antarctica, and its biological effects." Science 163: 273-274.

Dayton, P. K., G. A. Robilliard, and R. T. Paine. (1970). "Benthic faunal zonation as a result of anchor ice at McMurdo Sound, Antarctica." Antarctic Ecology. New York, Academic Press. 1: 244-258.

Dayton, P. K. and J. S. Oliver. (1977). "Antarctic soft-bottom benthos in oligotrophic and eutrophic environments." Science 197: 55-58.