Major Ocean Basins

One World Ocean

The ocean is the defining physical feature on our planet Earth—covering approximately 70% of the planet’s surface. There is one ocean with many features and ocean basins.

Ocean basins are composed of the seafloor and all of its geological features (such as islands, trenches, mid-ocean ridges and rift valleys) and vary in size, shape and features due to the movement of Earth’s crust. Earth’s highest peaks, deepest valleys and flattest vast plains are all in the ocean.

Pacific Ocean Basin

–Largest basin (areal coverage 180,000,000 km2)

–Deepest (average depth 3,940 m)

–Extensive marginal seas and volcanic island systems and trenches

–Considerable mountain building and earthquake activity along boundaries

–Little freshwater input (not many major rivers drain into it)

Atlantic Ocean Basin

– Second largest basin (areal coverage 107,000,000 km2)

– Average depth 3,310 m

– Large freshwater input (Amazon, Congo, Mississippi, Niger, Orinoco Rivers)

– Small number of marginal seas (Gulf of Mexico, Caribbean, Mediterranean)

Indian Ocean Basin

– Basin areal coverage 74,000,000 km2

– Average depth 3,840 m

– Large sediment input (Indus and Ganges River deltas)

– Small number of marginal seas (Arabian Sea, Persian Gulf, and Red Sea)

Southern Ocean Basin

– Areal coverage 20,327,000 km2

– Average depth 3,270m

– Continuous ring of water around the Antarctic continent (south pole) bordered to the north by the line of latitude at 60° S (approximate position of the Antarctic Circumpolar Current)

– Coldest of all oceans (near freezing)

– Most biologically productive ocean (high nutrient concentrations)

– Extensive winter sea ice coverage

– Small number of marginal seas (Weddell and Ross Seas)

Arctic Ocean Basin

– Smallest basin (areal coverage 14,056,000 km2)

– Average depth 1,038 m

– Centered on the north pole

– Shallow and land-locked

 – Covered by sea ice

– Large sediment input from active glaciers