1.1 Overview of the Oceans

The Five Major Oceans

While Earth has one continuous World Ocean, it is traditionally divided into five named ocean basins: Pacific, Atlantic, Indian, Southern (Antarctic), and Arctic. Each has distinct characteristics.

Ocean Basin Characteristics

Pacific Ocean

Largest and deepest, Ring of Fire, most islands

Area: 168.7M km²

Avg depth: 4,280 m

46% of ocean

Atlantic Ocean

S-shaped, Mid-Atlantic Ridge, youngest ocean

Area: 85.1M km²

Avg depth: 3,646 m

23% of ocean

Indian Ocean

Warmest ocean, monsoon-driven circulation

Area: 70.6M km²

Avg depth: 3,741 m

20% of ocean

Southern Ocean

Antarctic Circumpolar Current, coldest waters

Area: 21.9M km²

Avg depth: 3,270 m

6% of ocean

Arctic Ocean

Smallest, shallowest, sea ice coverage

Area: 15.6M km²

Avg depth: 1,205 m

4% of ocean

Ocean Zones by Depth

Epipelagic (Sunlight)(0-200 m)
Phytoplankton, fish, marine mammals
Mesopelagic (Twilight)(200-1000 m)
Bioluminescent organisms, migrators
Bathypelagic (Midnight)(1000-4000 m)
Giant squid, anglerfish
Abyssopelagic (Abyssal)(4000-6000 m)
Sparse, adapted to pressure
Hadopelagic (Trenches)(6000-11000 m)
Amphipods, specialized bacteria

Key Statistics

Volume

1.335 billion km³

97% of Earth's water

Average Temperature

3.5°C (38.3°F)

Cold deep water dominates

Explored

~5-20%

Most ocean remains unexplored

Coastline

1.6 million km

Global coastline length

← Part 1 OverviewOcean Basins →