Arctic Vessels

The Arctic region can be defined as the area north of the Arctic Circle (66° 33’N), which is the approximate limit of the midnight sun and the polar night. Alternatively, it can be defined as the region where the average temperature for the warmest month (July) is below 10 °C (50 °F); the northernmost tree line roughly follows the isotherm at the boundary of this region. Socially and politically, the Arctic region includes the northern territories of the eight Arctic states, although by natural science definitions much of this territory is considered subarctic.
The Arctic region consists of a vast, ice-covered ocean (which is sometimes considered to be a northern arm of the Atlantic Ocean) surrounded by treeless permafrost. In recent years the extent of the sea ice has declined. Life in the Arctic includes organisms living in the ice, zooplankton and phytoplankton, fish and marine mammals, birds, land animals, plants, and human societies.