The smallest of the world’s five oceans is the Arctic Ocean. Located in the Northern Hemisphere and largely within the Arctic Circle, it occupies the planet’s northernmost region. While its polar location and relatively shallow depth distinguish it from the other four oceans, its size is the definitive factor in its classification as the smallest. This frigid expanse is surrounded by the landmasses of North America, Eurasia, and Greenland.
The Arctic Ocean’s Precise Dimensions
The Arctic Ocean covers an area of approximately 5.4 million square miles (14 million square kilometers). This size is roughly five times larger than the largest sea, the Mediterranean, yet it represents only about 4.3 percent of the global ocean surface area.
The ocean is also the shallowest of the five, possessing an average depth of about 3,240 to 3,406 feet (987 to 1,038 meters). The average depth of the Pacific Ocean is over four times greater for comparison. The Arctic’s shallow nature is due to its wide continental shelf, which underlies nearly one-third of its total area, with the Siberian and Chukchi shelves being particularly expansive. The deepest point recorded in the Arctic Ocean is approximately 18,050 feet (5,502 meters), found in the Eurasian Basin.
Distinguishing Oceans from Seas
The classification of the Arctic as an “ocean” rather than a “sea” relies on geographical criteria and historical convention. Oceans are generally defined as vast, deep, continuous bodies of saltwater that are typically bounded by continents or characterized by major underwater features. Seas, conversely, are smaller, shallower, and often partially enclosed by land, usually found on the margins of oceans.
The Arctic Ocean meets the criteria for ocean status because it is one of the five principal divisions of the interconnected World Ocean. It possesses its own distinct system of currents and water masses, and its deepest basins, like the Eurasia Basin, are underlain by oceanic crust. The sheer scale of the Arctic Ocean, at 14 million square kilometers, also supports its classification, as it is significantly larger than the world’s largest seas. Therefore, despite its physical characteristics—being the smallest and shallowest—the Arctic is structurally and functionally an ocean.
Unique Physical and Climatic Features
The Arctic Ocean’s defining feature is its extensive and perennial cover of sea ice, which characterizes its unique climate and environment. This ice cover varies seasonally, growing throughout the winter and significantly retreating during the summer months. The presence of this ice dramatically reduces the exchange of energy between the water and the atmosphere, impacting global weather patterns.
Another distinctive feature is the ocean’s remarkably low average salinity compared to the other major oceans. This is largely due to the massive inflow of freshwater from Siberian and North American rivers, coupled with low rates of evaporation in the cold climate. The limited exchange of water with the more saline Atlantic and Pacific Oceans also contributes to this lower salt concentration.
The combination of extreme cold and persistent ice has resulted in a specialized cold-water ecosystem. Marine life has adapted to depend heavily on the sea ice for hunting, breeding, and resting. The cold temperatures and ice coverage also influence the mixing of water layers, leading to the formation of dense, cold water masses that contribute to global ocean circulation.