Cold and Isolated Waters: From the Arctic Ocean to Lake Vostok

The smallest, shallowest and coldest of the oceans, centered on the North Pole and largely covered by drifting sea ice that thickens each winter and retreats each summer. Much of its water arrives from the Atlantic and Pacific through narrow connecting straits, which is why the next stop follows.

This is one of those narrow connections, joining the Pacific Ocean through the Bering Sea to the Arctic Ocean through the Chukchi Sea. It is only about 82 kilometers across at its narrowest and about 90 meters deep at most, and in past glacial periods, when sea levels fell, it exposed the Beringia land bridge associated with early human migration between Asia and North America.

On the east coast of Greenland, opening into the Greenland Sea, this is a tree-like fjord system covering roughly 38,000 square kilometers, with depths reaching 1,450 meters. It ranks among the largest and longest fjord systems in the world, yet has a single permanent settlement, Ittoqqortoormiit.

The ocean encircling Antarctica, defined less by coastlines than by the Antarctic Circumpolar Current, the eastward flow that isolates Antarctic waters from the Atlantic, Pacific and Indian Oceans. It was formally recognized as the fifth ocean in 2021 by the United States Board on Geographic Names and the National Oceanic and Atmospheric Administration.

An arm of the Southern Ocean off Marie Byrd Land in western Antarctica, lying between Cape Flying Fish and Cape Dart on Siple Island. A Norwegian expedition under Captain Nils Larsen named it for the polar explorer Roald Amundsen in February 1929.

A marginal sea of the Southern Ocean whose southern limit is the Ross Ice Shelf, the largest ice shelf on the continent, charted by James Clark Ross in 1841. In October 2016 the Ross Sea region was designated a marine protected area of about 1.55 million square kilometers, the largest in the world at the time.

Far from the poles, this rift lake in southern Siberia is the deepest lake on Earth, formed in a tectonic rift more than twenty-five million years ago. Its long isolation has produced an unusually high number of species found nowhere else, a useful comparison for the isolated lake at the final stop.

The largest of Antarctica's 675 known subglacial lakes, lying beneath Russia's Vostok Station under the central East Antarctic Ice Sheet. Its surface sits about 4,000 meters beneath the ice, approximately 500 meters below sea level.