océans

Océans (oceans) are vast, interconnected bodies of saltwater that cover about 71% of Earth's surface and hold roughly 97% of the planet's liquid water. They form a single global sea divided into five major basins: the Pacific, Atlantic, Indian, Southern, and Arctic oceans. The average depth is about 3,700 meters, and the deepest point, the Challenger Deep in the Mariana Trench, reaches about 10,972 meters. Salinity averages around 35 practical salinity units, with regional variations.

The oceans influence global climate by storing and transporting heat through currents, regulating atmospheric gas concentrations, and driving the water cycle. They are characterized by physical features such as currents, waves, thermoclines, and deep-sea trenches, as well as diverse ecosystems from coral reefs and kelp forests to open-ocean pelagic communities and polar seas. Life ranges from microbial communities to large mammals like whales.

Humans rely on oceans for food, transportation, recreation, and climate regulation, but activities pose threats including overfishing, habitat destruction, pollution, plastic debris, and ocean acidification from rising CO2. Conservation and management efforts focus on sustainable fisheries, pollution reduction, marine protected areas, and international governance.

Governing frameworks such as UNCLOS define territorial seas up to 12 nautical miles and exclusive economic zones up to 200 nautical miles, while international cooperation addresses offshore energy, seabed mining, and biodiversity protections. The study of oceans, or oceanography, developed from early seafaring and expanded with sonar, satellites, and submersibles, yielding essential data for science and policy.