The underlying rocks are of upper Precambrian to lower Paleozoic age and are partly composed of calcium carbonate. The circulation of the Ross Sea is dominated by a wind-driven ocean gyre and the flow is strongly influenced by three submarine ridges that run from southwest to northeast. The circumpolar deep water current is a relatively warm, salty and nutrient-rich water mass that flows onto the continental shelf at certain locations. The Ross Sea is covered with ice for most of the year.
The nutrient-laden water supports an abundance of plankton and this encourages a rich marine fauna. At least ten mammal species, six bird species and 95 fish species are found here, as well as many invertebrates, and the sea remains relatively unaffected by human activities. New Zealand has claimed that the sea comes under their jurisdiction as part of the Ross Dependency. Marine biologists consider the sea to have a high level of biological diversity and it is the site of much scientific research. It is also the focus of some environmentalist groups who have campaigned to have the area proclaimed as a world marine reserve.
The Ross Sea was discovered by James Ross in 1841. In the west of the Ross Sea is Ross Island with the Mt. Erebus volcano, in the east Roosevelt Island. The southern part is covered by the Ross Ice Shelf. Roald Amundsen started his South Pole expedition in 1911 from the Bay of Whales, which was located at the shelf. In the west of the Ross sea, McMurdo Sound is a port which is usually free of ice during the summer. The southernmost part of the Ross Sea is Gould Coast, which is approximately two hundred miles from the geographic South Pole.
A 10-metre (32.8 feet) long colossal squid weighing 495 kilograms (1,091 lb) was captured in the Ross Sea on February 22, 2007.
Ross System rocks are of upper Precambrian to lower Paleozoic age and each group of Ross System have an echelon vein pattern demonstrating possible dextral faulting. These miogeosyncline metasedimentary rocks are usually folded about northwest and southeast axes and are partly composed of calcium carbonate, often including limestone. Groups within the Ross System include the Robertson Bay Group, Priestley Group, Skelton Group, Beardmore Group, Byrd Group, Queen Maud Group, and Koettlitz Group. The Robertson Bay Group ranges from 56 to 76% silica and compares closely with other Ross System members. The Priestley Group rocks are similar to those of the Robertson Bay Group and include dark slates, argillites, siltstones, fine sandstones and limestones. They can be found near the Priestley and Campbell glaciers. For thirty miles along the lower Skelton Glacier are the calcareous greywackes and argillites of the Skelton Group. The region between the lower Beardmore Glacier and the lower Shackelton Glacier sits the Beardmore Group. North of the Nimrod Glacier are four block faulted ranges that make up the Byrd Group. The contents of the Queen Maud Group area are mainly post-tectonic granite.