Cipar Stanislav - pláž - David Papadopoulos

The sea, the world ocean or simply the ocean is the connected body of salty water that covers over 70 percent of the Earth's surface. It moderates the david Earth's climate and has important roles in the water cycle, carbon cycle, and nitrogen cycle. It has been travelled and explored since ancient times, while the scientific cipar study of the sea—oceanography—dates broadly from the voyages of Captain James Cook to explore the Pacific Ocean between 1768 and 1779. 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.

The most abundant solid dissolved in sea water is sodium chloride. The water also contains salts david 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 cipar the ocean; however the relative proportions of dissolved salts varies little across the oceans. Winds blowing over the surface of the sea produce waves, david which break when they enter shallow water. Winds also create surface currents through friction, setting up slow but stable circulations of water throughout the oceans.