Hydrosphere in the Earth System

The hydrosphere is interconnected with all the other 'spheres' in the Earth system, that is, the geosphere (lithosphere and atmosphere), biosphere, and human-related anthroposphere (which includes technosphere). A temporarily immobilized part of the hydrosphere - ice and snow - is sometimes called the cryosphere, while the domain of salty water is sometimes called the oceanosphere.

Water is abundant in all the 'spheres' of the Earth system, in liquid, solid, and vapor states. There is water stored over the Earth's surface and in the atmosphere. There is abundance of water on the Earth's surface (hydrosphere: oceans and seas, polar ice, lakes, rivers

Table 1 Physical characteristics of water for three temperatures (0, 20, and 100 °C)

Temperature

Surface tension

Dynamic viscosity

Saturation vapor pressure

Density

(°C)

(erg cm 2)

(kg m -1 s-")

(kPa)

(g cm"3)

0

75.6

0.001 792

0.611

Liquid 0.9999

Solid 0.9150

20

72.8

0.001 003

2.339

Liquid 0.9982

100

61.5

0.000282

101.3

Liquid 0.9584

Gaseous 0.0006

At the temperature of 4 °C, the maximum water density of 1.0 g cm"3 is observed.

Temperature of melting: 0 °C (at pressure of 1013 hPa).

Temperature of boiling: 100 °C (at pressure of 1013 hPa).

Specific heat: 1.000 cal g"1 °C"1 (at 14.5 °C).

Latent heat of evaporation (vaporization) 597.3 cal g"1 (at 100 °C).

Latent heat of sublimation 677.0 cal g"1 (at 0 °C).

Water is a poor conductor of electricity and its compressibility is very low.

At the temperature of 4 °C, the maximum water density of 1.0 g cm"3 is observed.

Temperature of melting: 0 °C (at pressure of 1013 hPa).

Temperature of boiling: 100 °C (at pressure of 1013 hPa).

Specific heat: 1.000 cal g"1 °C"1 (at 14.5 °C).

Latent heat of evaporation (vaporization) 597.3 cal g"1 (at 100 °C).

Latent heat of sublimation 677.0 cal g"1 (at 0 °C).

Water is a poor conductor of electricity and its compressibility is very low.

and streams, wetlands and marshes, snow pack and glaciers; containing liquid and solid water) and in the lithosphere (solid Earth), under the Earth's surface (in the rocks and soil, including permafrost, and deeper in the ground, down to the Earth crust - in liquid, solid, and gaseous phases), and in the biosphere (in plants and animals). The water is on a perpetual move; it partakes in processes of exchange of mass and energy between the various spheres of the Earth system. The main, in volumetric terms, water transfer takes place between the hydrosphere and the atmosphere in processes of evaporation and precipitation. The evaporation process purifies (distills) salty oceanic water into freshwater. Water moves not only in the processes of evaporation, precipitation, and infiltration, or flow in rivers and streams, plants and animals, but also in oceans, seas, and lakes, in snow pack, and in even seemingly immobile glaciers.

The total volume of water in the hydrosphere is nearly constant over a longer timescale, with negligible changes due to gain of juvenile water through emergence of vapor via volcanic eruptions or seepage in sea floor, and loss of water bonded and buried in crustal sediments and by chemical breakdown (hydrolysis).

Presence of water, and its movement, is responsible for the chemical and mechanical breakdown of rocks in the lithosphere. Successive freezings of water (with volumetric expansion), and thawings, crack even the most durable rocks. In this process, called weathering, the rocks are partitioned into smaller pieces, and finally into stone, gravel, sand, and soil. Erosion induced by precipitation falling on the Earth's surface is responsible for sculpting the surface of the Earth. Geomorphological processes induced by running water form stream channels. Water transports the solid material to surface water bodies (rivers, lakes), seas, and oceans. Global sediment fluxes are very high, and may amount to 9.3-64.0 Gt yr_1, depending on the source of estimates.

Water plays an essential role in the functioning of the biosphere. The solvent properties of water are indispensable in the life processes of transport of nutrients in organisms. In result of the water transfer between the hydrosphere and the biosphere, plants take water (with dissolved nutrients) from the soil. High surface tension of water explains the capillary movement of water (carrying nutrients) from the ground, in plants from their roots through their vascular system to stems and leaves. Further, there is water transfer from plants to the atmosphere via the leaf surfaces in a process called transpiration, which is of critical importance for the thermoregulation.

It is indeed a paradoxical property that warm water (4 °C) in lakes, ponds, and rivers is located near the bottom, under ice cover (lighter than water), which separates a warmer water body from a much colder environment. The existence of the ice cover prevents many lakes and rivers from freezing to the bottom during cold winters (with disastrous consequences to aquatic life).

The term 'anthroposphere' relates to the existence of 6.5 billion active human beings populating the Earth, and the human-created technosphere. Man has significantly impacted the water cycle on Earth, in both quantity and quality aspects, in particular through the water withdrawal for agricultural irrigation and industrial processes, including energy production. Man is responsible for widespread contamination of surface and ground waters.

Was this article helpful?

0 0
Oplan Termites

Oplan Termites

You Might Start Missing Your Termites After Kickin'em Out. After All, They Have Been Your Roommates For Quite A While. Enraged With How The Termites Have Eaten Up Your Antique Furniture? Can't Wait To Have Them Exterminated Completely From The Face Of The Earth? Fret Not. We Will Tell You How To Get Rid Of Them From Your House At Least. If Not From The Face The Earth.

Get My Free Ebook


Post a comment