Hydrosphere and its structure

The hydrosphere is the liquid water component of the Earth. It includes the oceans, seas, lakes, ponds, rivers and streams. The hydrosphere covers about 70% of the surface of the Earth and is the home for many plants and animals. Total capacity of hydrosphereis about 1,4 billion km². Only 2,58% is fresh water, another 97,5 are the Ocean and salt water on the land.Hydrosphere includes

ü the oceans

ü seas

ü lakes

ü ponds

ü rivers and

ü streams.

Water – the most widespread substance on the planet. Usable water in the world: oceans 97%, rivers, lakes and groundwater – 1%, glaciers – 2%. Composition of the earth’s water supply: 97,5% - salt water, 2,5% - fresh water, 0,01% - available fresh water.

According to chemical composition water is the hydrogen oxide – H2O. Properties of water include

ü aggregate state

ü when water freezes, it increases its capacity

ü water is solvent

ü water warms slowly and gets cold slowly.

Water cycle

Continuous cycle water movement in atmosphere, hydrosphere, lithosphere, which takes place under influence of the solar energy and gravity force, is called world water cycle. It includes such processes as evaporation, condensation, precipitation, surface runoff etc.

The water cycle, also known as the hydrologic cycle or the H2O cycle, describes the continuous movement of water on, above and below the surface of the Earth. The mass of water on Earth remains fairly constant over time but the partitioning of the water into the major reservoirs of ice, fresh water, saline water and atmospheric water is variable depending on a wide range of climatic variables. The water moves from one reservoir to another, such as from river to ocean, or from the ocean to the atmosphere, by the physical processes of evaporation, condensation, precipitation, infiltration, runoff, and subsurface flow. In so doing, the water goes through different phases: liquid, solid (ice), and gas (vapor).

The water cycle involves the exchange of energy, which leads to temperature changes. For instance, when water evaporates, it takes up energy from its surroundings and cools the environment. When it condenses, it releases energy and warms the environment. These heat exchanges influence climate. The evaporative phase of the cycle purifies water which then replenishes the land with freshwater. The flow of liquid water and ice transports minerals across the globe. It is also involved in reshaping the geological features of the Earth, through processes including erosion and sedimentation. The water cycle is also essential for the maintenance of most life and ecosystems on the planet.

2. The World Ocean and its parts.

World Ocean

ü total capacity is about 1 billion 370 million km

ü 94% of hydrosphere

ü There are 73 from 110 chemical elements in its waters.

ü includes oceans, seas, gulfs and channels. There are four oceans.

The Pacific Ocean

The Pacific is the largest and the deepest of all, its total area is greater than that of all the dry land

The Atlantic Ocean

The Atlantic Ocean stretches from the Arctic Ocean downward to the shores of Antarctica. This makes it the same size from north to south as the Pacific Ocean. However, from east to west, the Atlantic Ocean is only about half as wide as the Pacific.

The Indian Ocean

The Indian Ocean is only slightly smaller than the Atlantic. The Indian Ocean lies between Africa on the west, Australia on the east, Asia on the north, and Antarctica on the south. 90% of this ocean lies to the south of the Equator.

The Arctic Ocean

The smallest ocean is the Arctic Ocean with the North Pole in the centre. This ocean is connected to the Pacific and Atlantic Oceans via small gaps between continents

Seas.Small and large parts of ocean that are divided by land, islands or underwater uplands are called seas. The largest seas are the Philippine Sea, the Coral Sea, the Arabian Sea, the South China Sea, the Caribbean Sea and others.

Gulf is a component of oceans, seas, lakes, which juts out the land, but has free exchange with their major parts. For example: the Persian Gulf, the Gulf of Mexico, the Gulf of Alaska etc.

Channel is rather narrow space, which connect water area with any separate land’s parts. Canal – man-made basin. (Suez, Panama Canals)

Land’s waters.

Ground waters, rivers, lakes, glaciers, bogs, artificial reservoirs are related to theland’s waters. They contain 3,5% of the waters total amount in hydrosphere. 2,5% from them is fresh water.

A river is a natural watercourse usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely at the end of its course, and does not reach another body of water. Rivers are constant kills, flowing in their hollows – beds. The longest rivers are the Nile, the Amazon, the Yangtze, the Huang He, the Ob-Irtysh and others.

Lake is the natural reservoir, filling up with water, which has not a direct connection with the World Ocean. Lakes occupy about 2% of the land and are situated unevenly. The world’s largest rivers are the Caspian Sea, Superior, the Aral Sea, Huron, Victoria and others.

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. Lakes can be contrasted with rivers or streams, which are usually flowing. However most lakes are fed and drained by rivers and streams.