The body of salt water that covers approximately 70.8% of the Earth and contains 97% of its water is known as the ocean (also known as the sea or the world ocean). Any of the enormous bodies of water into which the world’s ocean is traditionally divided can also be referred to as an ocean.

Five distinct areas of the ocean are identified by distinct names: Seawater covers approximately 361,000,000 km2 (139,000,000 sq mi) of the planet, with the Pacific being the largest and the Atlantic the smallest. Since the ocean is the most important part of Earth’s hydrosphere, it is essential to life on Earth. The ocean has an impact on the carbon cycle, the water cycle, and the climate and weather patterns because it serves as a huge heat reservoir.

Oceanographers partition the sea into various vertical and flat zones in light of physical and organic circumstances. The open ocean’s water column extends from the surface to the ocean floor, making up the pelagic zone. The water column is further divided into additional zones based on depth and the amount of light present. In the open ocean, the photic zone contains water up to a depth of 200 meters, or 1% of the surface light, where photosynthesis can take place.

The photic zone is therefore the most biodiverse. Using light, water, carbon dioxide, and nutrients, plants and microscopic algae (free floating phytoplankton) produce organic matter through photosynthesis. Sea photosynthesis makes half of the oxygen in earth’s climate. The majority of the ocean ecosystem’s food supply originates in this upper sunlit zone. Only a few hundred meters of depth can be reached by light; The remaining cold and dark ocean is below. With a depth of a few hundred meters or less, the continental shelf where the ocean meets dry land is shallower. The continental shelf experiences the greatest impact from human activity.