Information about Estuary

For other meanings, see Estuary (disambiguation)

An estuary is a semi-enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea.^[1] Estuaries are often associated with high rates of biological productivity. An estuary is where the river meets the sea.

An estuary is typically the tidal mouth of a river (aestus is Latin for tide), and estuaries are often characterized by sedimentation or silt carried in from terrestrial runoff and, frequently, from offshore. They are made up of brackish water. Estuaries are more likely to occur on submerged coasts, where the sea level has risen in relation to the land; this process floods valleys to form rias and fjords. These can become estuaries if there is a stream or river flowing into them. Large estuaries, like Chesapeake Bay and Puget Sound often have many streams flowing into them and can have complex shapes. Estuaries are often given names like bay, sound, fjord, etc. The terms are not mutually exclusive. Where an enormous volume of river water enters the sea (as, for example, from the Amazon into the South Atlantic) its estuary could be considered to extend well beyond the coast.

Estuarine circulation is common in estuaries; this occurs when fresh or brackish water flows out near the surface, while denser saline water flows inward near the bottom. Anti-estuarine flow is its opposite, in which dense water flows out near the bottom and less dense water circulates inward at the surface. These two terms, however, have a broader oceanographic application that extends beyond estuaries proper, such as in describing the circulation of nearly-closed ocean basins. Estuaries are marine environments, whose pH, salinity, and water level are varying, depending on the river that feeds the estuary and the ocean from which it derives its salinity (oceans and seas have different salinity levels).

Classes of estuary

Salt wedge: River output greatly exceeds marine input; there is little mixing, and thus a sharp contrast between fresh surface water and saline bottom water. ; Highly stratified : River output and marine input are more even, with river flow still dominant; turbulence induces more mixing of salt water upward than the reverse. ;Slightly stratified : River output is less than the marine input. Here, turbulence causes mixing of the whole water column, such that salinity varies more longitudinally rather than vertically. ; Vertically mixed : River output is much less than marine input, such that the freshwater contribution is negligible; longitudinal salinity variation only. ; Inverse estuary : Located in regions with high evaporation, there is no freshwater input and in fact salinity increases inland; overall flow is inward at the surface, downwells at the inland terminus, and flows outward subsurface. ; Intermittent estuary : Estuary type varies dramatically depending on freshwater input, and is capable of changing from a wholly marine embayment to any of the other estuary types.^[2]

Grouped by structure rather than circulation, there are other types of estuaries. Bar-built estuaries are effectively synonymous with barrier island lagoons, such as Texas's Laguna Madre. Tectonic estuaries form when the sea floods a geologically subsident region, coastal plain estuaries are flooded river valleys, and fjords are submerged glacier-eroded valleys.^[3]

References

1. ^ Pritchard, D. W. (1967) What is an estuary: physical viewpoint. p. 3–5 in: G. H. Lauf (ed.) Estuaries, A.A.A.S. Publ. No. 83, Washington, D.C.
2. ^ M. Tomczak, "Oceanography Notes Ch. 12: Estuaries". Retrieved on 30 November 2006.
3. ^ "Types of Estuaries: Based on Geology". Retrieved on 1 December 2006.

Estuary can refer to:

Estuary, a semi-enclosed body of water flowing into the sea.
Estuary English, a variety of English spoken in the south east of England.
The Estuary can mean the region of the River Thames and adjoining communities east of Central London.

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coast is defined as the part of the land adjoining or near the ocean. A coastline is properly a line on a map indicating the disposition of a coast, but the word is often used to refer to the coast itself.
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Water is a common chemical substance that is essential to all known forms of life.^[1] In typical usage, water refers only to its liquid form or state, but the substance also has a solid state, ice, and a gaseous state, water vapor.
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river is a natural waterway that transits water through a landscape from higher to lower elevations. It is an integral component of the water cycle. The water within a river is generally collected from precipitation through surface runoff, groundwater recharge (as seen at baseflow
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worldwide view.

This article or section deals primarily with the United Kingdom and does not represent a worldwide view of the subject.
Please [ improve this article] or discuss the issue on the talk page.

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The three-letter acronym SEA may refer to:

Scientists and Engineers for America, a pro-science political advocacy group.
Schoof-Elkies-Atkin algorithm
Seattle-Tacoma International Airport (IATA: SEA, ICAO: KSEA)
Sea Education Association

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Sedimentation describes the motion of molecules in solutions or particles in suspensions in response to an external force such as gravity, centrifugal force or electric force.
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Silt is soil or rock derived granular material of a specific grain size. Silt may occur as a soil or alternatively as suspended sediment in a water column of any surface water body. It may also exist as deposition soil at the bottom of a water body.
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Brackish water (less commonly brack water) is water that is saltier than fresh water, but not as salty as seawater. It may result from mixing of seawater with fresh water, as in estuaries, or it may occur in brackish fossil aquifers.
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Submergent coastlines are stretches along the coast that have been inundated by the sea due to a relative rise in sea levels. This occurs due to either isostacy or eustacy.
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geology, a valley is a depression with predominant extent in one direction. A very deep river valley may be called a canyon or gorge.

The terms U-shaped and V-shaped are descriptive terms of geography to characterize the form of valleys.
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RIA can stand for:

RIA (Russian Information Agency) Novosti
Royal Irish Academy
Rich Internet Application
Research into Ageing
Radioimmunoassay
Regional Intelligence Analyst
Research Institute of America

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fjord (or fiord) is a long, narrow estuary with steep sides, made when a glacial valley is filled by rising sea water levels. The seeds of a fjord are laid when a glacier cuts a U-shaped valley through abrasion of the surrounding bedrock by the rocks and sediment it carries.
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Chesapeake Bay is the largest estuary in the United States. It lies off the Atlantic Ocean, surrounded by Maryland and Virginia. The Chesapeake Bay's watershed covers 64,299 square miles (166534 km)
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Puget Sound (pronounced IPA [ˈpjuʤɨt]) is an arm of the Pacific Ocean, connected to the rest of the Pacific by the Strait of Juan de Fuca, in the Pacific Northwest of the United States.
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headland is an area of land adjacent to water on three sides. A bay is the reverse, rather an area of water bordered by land on three sides. A large headland may also be called a peninsula. Long, narrow and high headlands may be called promontories.
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sound is a large sea or ocean inlet larger than a bay, deeper than a bight, wider than a fjord, or it may identify a narrow sea or ocean channel between two bodies of land (see also strait).

There is little consistency in the use of 'sound' in English-language cartography.
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Oceanography (from Ocean + Greek γράφειν = write), also called oceanology or marine science, is the branch of Earth Sciences that studies the Earth's oceans and seas.
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pH is a measure of the acidity or alkalinity of a solution. Aqueous solutions at 25 ℃ with a pH less than seven are considered acidic, while those with a pH greater than seven are considered basic (alkaline). The pH of 7.
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Salinity is the saltiness or dissolved salt content of a body of water. Salinity in Australian English and North American English may refer to salt in soil (see soil salination).

Definition

Water salinity
Fresh water Brackish water Saline water Brine
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shoal is a somewhat linear landform within or extending into a body of water, typically comprised of sand, silt or small pebbles. Alternatively termed sandbar or sandbank
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lagoon is a body of comparatively shallow salt or brackish water separated from the deeper sea by a shallow or exposed sandbank, coral reef, or similar feature. Thus, the enclosed body of water behind a barrier reef or barrier islands or enclosed by an atoll reef is called a
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State of Texas

Flag of Texas Seal
Nickname(s): Lone Star State
Motto(s): Friendship.
Before Statehood Known as
The Republic of Texas

Official language(s) No official language

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Laguna Madre is a long, shallow bay along the western coast of the Gulf of Mexico in the United States and Mexico. Meaning "mother lagoon" in Spanish, the Laguna Madre proper is 130 miles (209 km) long, the length of Padre Island; its biological corridor, though, extends well into
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Oceanic crust 0-20 Ma
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subsidence is the motion of a surface (usually, the Earth's surface) as it shifts downward relative to a datum such as sea-level. The opposite of subsidence is uplift, which results in an increase in elevation.
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Estuary

Classes of estuary

See also

References

Definition