Sea

Earth’s 1,335,000,000 cubic kilometers of sea contain about 97% of its known water and cover more than 70 percent of its surface. The sea provides substantial supplies of food for humans, mainly fish, but also shellfish, mammals and seaweed. Other human uses of the sea include trade, travel, mineral extraction, power generation, warfare, and leisure activities.

About Sea in brief

Summary Sea The sea, the world ocean, or simply the ocean is the connected body of salty water that covers about 71% of Earth’s surface. It moderates Earth’s climate and has important roles in the water cycle, carbon cycle, and nitrogen cycle. The word sea is also used to denote smaller, partly landlocked sections of the ocean and certain large, entirely landlocked, saltwater lakes, such as the Caspian Sea and the Dead Sea. Earth’s 1,335,000,000 cubic kilometers of sea contain about 97% of its known water and cover more than 70 percent of its surface. Earth is the only known planet with seas of liquid water on its surface, although Mars possesses ice caps and similar planets in other solar systems may have oceans. The sea provides substantial supplies of food for humans, mainly fish, but also shellfish, mammals and seaweed, whether caught by fishermen or farmed underwater. Other human uses of the sea include trade, travel, mineral extraction, power generation, warfare, and leisure activities such as swimming, sailing, and scuba diving. The scientific study of water and Earth’s cycle is hydrology; hydrodynamics studies the physics of water in motion. The more recent study of the water in particular is oceanography, which began as the study of ocean currents but has expanded into a multidisciplinary study of large and large currents, including the shape of the oceans and their currents. The study of sea in particular began as theStudy of oceanography began in the 1970s, but has since expanded into multidisciplined studies of the shape and motion of the seas.

The most abundant solid dissolved in seawater is sodium chloride. The water also contains salts of magnesium, calcium, and potassium, amongst many other elements, some in minute concentrations. Salinity varies widely, being lower near the surface and the mouths of large rivers and higher in the depths of the Ocean. Tides, the generally twice-daily rise and fall of sea levels, are caused by Earth’s rotation and the gravitational effects of the orbiting Moon and, to a lesser extent, of the Sun. Submarine earthquakes arising from tectonic plate movements under the oceans can lead to destructive tsunamis, as can volcanoes, huge landslides or the impact of large meteorites. A wide variety of organisms, including bacteria, protists, algae, plants, fungi, and animals, live in the sea, which offers a wide range of marine habitats and ecosystems, ranging vertically from the sunlit surface and shoreline to the great depths and pressures of the cold, dark abyssal zone, and in latitude from the cold waters under polar ice caps to the colourful diversity of coral reefs in tropical regions. There is no sharp distinction between seas and oceans, though generally seas are smaller, and are often partly or wholly bordered by land. Seas are generally larger than lakes and contain salt water, but the Sea of Galilee is a freshwater lake. The United Nations Convention on the Law of the Sea states that all of theOcean is \”sea\”.