A marginal sea located off Antarctica from approximately 70 to 100° W northwards to the Antarctic Circle. It is located between Thurston Island to the west and the Antarctic Peninsula to the east and was named for the Russian admiral Baron Fabian Gottlieb von Bellingshausen who led an expedition to Antarctic waters at the behest of Alexander I in 1819. He is considered the first to have actually discovered the continent of Antarctic, those preceding him not having seen it because of ice and low visibility. The geographic features include Ronne and Marguerite Bay as well as Peter I, Charcot and Alexander I Islands.