An ocean is a major body of saline water, and a principal component of the hydrosphere. Approximately 71% of the Earth's surface is covered by ocean.

The ocean has a important effect on the biosphere. Oceanic evaporation as a phase of the water cycle is source of rainfall and ocean temperatures define climate and wind. Life inside the ocean was evolved 3 billion years before life on the ground. Water depth and distance from coast have big effect on shoal and kinds of plants and animals who live there.

Ocean currents is manipulated to the world weather. Currents are turned around and carry warm and cold weather. Cold is come from poles and warmth is come from equator. Most famous current is the Gulf Stream The Gulf Stream surface current is a western boundary current, one of the strongest- warm, deep, fast, and relatively salty. It separates open-ocean water from coastal water

People are fished in the oceans by large nets. Nets are hunged on the big fishing boats. Fishing boats caught millions tune of fish every year.

Giant tankers are transported oil through the oceans. This form of transport is dangerous for life in oceans. In years 1970 till 1985 was 185 big accident. In this accident escaped 1300 ton of oil. In 1989, ton of oil was escaped from tanker Exxon and oil was covered area 4200 km². But oil is escaped during normal transports too.

8.June – World's ocean day

World ocean is covered by four oceans: Pacific ocean Pacific ocean ( The pacific ocean is the largest of the Earth's oceans. ) Atlantic ocean Atlantic ocean (The Atlantic ocean is most exploited ocean.) Indian ocean Indian ocean (The Indian ocean is the saltiest ocean on the world) Southern ocean Southern ocean (The Southern ocean is least salty and cold ocean of all oceans.)

Specifications about world ocean: World ocean have an area about 361 million km². World ocean have an area about 361 million km². These ocean have capacity about million km³ too. These ocean have capacity about million km³ too. It have medial depth m. It have medial depth m.

Róbert Ondica 8.A Zdroje: Internet