The Arctic Ocean is the smallest and shallowest of the world’s five major oceanic divisions. Centered over the North Pole, it is largely surrounded by the landmasses of North America and Eurasia. Its defining characteristics, including extensive ice cover and physical dimensions, set it apart from the vast, deep basins of the other global oceans. It is the northernmost ocean and a distinct feature in global oceanography.
The Official Ranking of Earth’s Oceans
The Arctic Ocean is formally ranked as the smallest of the five oceans, following the Pacific, Atlantic, Indian, and Southern Oceans. This ranking is based on both surface area and total water volume. The Arctic Ocean spans a surface area of approximately 14.06 million square kilometers.
Its surface area is less than one-sixth that of the Indian Ocean, the next smallest major ocean. By volume, the Arctic Ocean contains only about 1.4% of the total water in the global ocean system.
Defining Characteristics of the Arctic Basin
The Arctic Ocean’s small size is tied to its unique physical structure, or bathymetry. It is notably the shallowest of the world’s oceans, possessing an average depth of only about 987 meters (3,240 feet). This is significantly shallower than the average depths of the Pacific or Atlantic Oceans.
This reduced depth is due to the presence of the widest continental shelves found anywhere in the world. Nearly one-third of the Arctic Ocean’s total area is underlain by these shallow submerged extensions of the surrounding continents. While the central basin contains soundings of approximately 5,500 meters, the vast Siberian and Chukchi shelves create shallow marginal seas.
The ocean is also characterized by a perennial or seasonal cover of sea ice. This ice cover reduces the exchange of heat and moisture between the ocean and the atmosphere, contributing to distinct physical and chemical properties. Furthermore, the Arctic Ocean receives substantial freshwater inflow from large Siberian and North American rivers, resulting in lower salinity compared to other oceans.
Geographic Boundaries and Naming Conventions
The classification of this body of water as an “ocean” is an important cartographical and political designation. The International Hydrographic Organization (IHO) officially recognizes it as one of the world’s five oceans, defining its geographical boundaries. These boundaries are drawn along specific topographic features, such as the Bering Strait, which connects it to the Pacific, and the Greenland-Scotland Ridge, which delineates its connection with the Atlantic.
Historically, some experts have debated the proper nomenclature, preferring to call it the “Arctic Mediterranean Sea” or “Arctic Mediterranean.” This alternative name reflects its nature as a largely landlocked sea, emphasizing its partial enclosure by landmasses, which limits its exchange of water with the larger, open oceans. Ultimately, the classification as the Arctic Ocean has become the globally accepted standard in modern geography and international affairs.