Arctic Ocean gas reserves, and the Chukchi shelf forms the border between Russian and the United States as stated in the USSR–USA Maritime Boundary Agreement. The whole area is subject to international territorial claims. An underwater ridge, the Lomonosov Ridge, divides the deep sea North Polar Basin into two oceanic basins: the Eurasian Basin, which is between deep, and the Amerasian Basin (sometimes called the North American, or Hyperborean Basin), which is about deep. The bathymetry of the ocean bottom is marked by fault block ridges, abyssal plains, ocean deeps, and basins. The average depth of the Arctic Ocean is . The
Fridtjof Nansen carried out researches in the northern Atlantic, and in 1912 he took his own yacht, "Veslemøy", to Bear Island and Spitsbergen. The main objective of the "Veslemøy" cruise was the investigation of salinity in the North Polar Basin. One of Nansen's lasting contributions to oceanography was his work designing instruments and equipment; the "Nansen bottle" for taking deep water samples remained in use into the 21st century, in a version updated by Shale Niskin. At the request of the Royal Geographical Society, Nansen began work on a study of Arctic discoveries, which developed into a two-volume history of the exploration