It may contain shallow water with marsh and aquatic plants and animals. It may arise naturally in floodplains as part of a river system, or be a somewhat isolated depression (such as a kettle, vernal pool, or prairie pothole). Many lakes are artificial and are constructed for industrial or agricultural use, for hydro-electric power generation or domestic water supply, or for aesthetic, recreational purposes, or other activities.Ī pond is an area filled with water, either natural or artificial, that is smaller than a lake. All lakes are temporary over geologic time scales, as they will slowly fill in with sediments or spill out of the basin containing them. In some parts of the world, there are many lakes because of chaotic drainage patterns left over from the last ice age. Other lakes are found in endorheic basins or along the courses of mature rivers. Natural lakes are generally found in mountainous areas, rift zones, and areas with ongoing glaciation. Most lakes are fed and drained by rivers and streams. Lakes can be contrasted with rivers or streams, which are usually flowing.

Lakes lie on land and are not part of the ocean, and therefore are distinct from lagoons, and are also larger and deeper than ponds, though there are no official or scientific definitions. Samur River in Azerbaijan – In the natural landscapeĪ lake is an area filled with water, localized in a basin, that is surrounded by land, apart from any river or other outlet that serves to feed or drain the lake. The total volume is approximately 1.35 billion cubic kilometers (320 million cu mi) with an average depth of nearly 3,700 meters (12,100 ft). The ocean contains 97% of Earth's water, and oceanographers have stated that less than 5% of the World Ocean has been explored. Saline water covers approximately 361,000,000 km 2 (139,000,000 sq mi) and is customarily divided into several principal oceans and smaller seas, with the ocean covering approximately 71% of Earth's surface and 90% of the Earth's biosphere. Strictly speaking, a sea is a body of water (generally a division of the world ocean) partly or fully enclosed by land, though ' the sea' refers also to the oceans. The word 'ocean' is often used interchangeably with 'sea' in American English. These are, in descending order by area, the Pacific, Atlantic, Indian, Southern (Antarctic), and Arctic Oceans. On Earth, an ocean is one of the major conventional divisions of the World Ocean. Oceans and seas Īn ocean is a body of water that composes much of a planet's hydrosphere. The ocean floors have been surveyed via sonar to at least a coarse resolution particularly-strategic areas have been mapped in detail, to assist in navigating and detecting submarines, though the resulting maps may be classified.

It can be mapped by sonar, or more directly explored via manned, remotely operated, or autonomous submersibles. The underwater environment is hostile to humans in many ways and therefore little explored. There is a smaller part of the surface covered by bodies of fresh water and a large volume of underground water in aquifers. The solid surface location on the planet closest to the center of the geoid is the Challenger Deep, located in the Mariana Trench at a depth of 10,924 metres (35,840 ft). Most of the planet's solid surface is abyssal plain, at depths between 4,000 and 5,500 metres (13,100 and 18,000 ft) below the surface of the oceans. Three quarters of the planet Earth are covered by water. The world ocean is the most visible part of Earth from space It is hostile to humans in many ways and often inaccessible, and therefore relatively little explored. These include research, underwater diving for work or recreation, and underwater warfare with submarines. Several branches of science are dedicated to the study of this environment or specific parts or aspects of it.Ī number of human activities are conducted in the more accessible parts of the underwater environment. The underwater environment is thought to be the place of the origin of life on Earth, and it remains the ecological region most critical to the support of life and the natural habitat of the majority of living organisms. Liquid water has been present on Earth for most of the history of the planet. Some characteristics of the underwater environment are universal, but many depend on the local situation.

For other uses, see Underwater (disambiguation).Īn underwater environment is a environment of, and immersed in, liquid water in a natural or artificial feature (called a body of water), such as an ocean, sea, lake, pond, reservoir, river, canal, or aquifer.

Underwater submarine kids