Ocean

Ocean refers to the single, connected saltwater body that covers about 71 percent of earth's surface. Scientists divide it into five major regions—the Pacific, Atlantic, Indian, Southern, and arctic Oceans—but currents, tides, and migrating animals flow between them. From shallow coral reefs to deep trenches, the ocean shapes coastlines, powers storms, and stores vast amounts of carbon and heat.

sunlight warms only the top layer called the photic zone, where phytoplankton use photosynthesis to produce oxygen. Below that, temperatures drop, pressure climbs, and strange life adapts to darkness. Hydrothermal vents on the seafloor release mineral-rich water that feeds unique communities of worms, clams, and bacteria.

Ocean water circulates constantly. Surface winds drive waves and currents such as the gulf Stream, which carries warm water toward europe. Deep-water circulation, sometimes called the global conveyor belt, sinks cold, salty water near the poles and slowly moves it through the deep ocean before it rises elsewhere. These motions regulate global climate by moving heat and nutrients.

Humans rely on the ocean for seafood, transportation, and energy. Ports move goods between continents, offshore wind farms harness sea breezes, and coastal cities attract tourists. At the same time, pollution, overfishing, and climate change threaten marine life and the industries that depend on it. plastic debris, excess carbon dioxide causing acidification, and rising sea levels are major concerns.

Protecting the ocean requires international cooperation. Marine protected areas safeguard habitats, fisheries managers set catch limits, and scientists monitor water quality from ships and satellites. Individuals can help by reducing plastic use, eating sustainable seafood, supporting clean-energy policies, and learning about ocean ecosystems.