estuary

(redirected from estuaries)
Also found in: Dictionary, Thesaurus, Medical.

estuary

(ĕs`cho͝oĕr'ē), partially enclosed coastal body of water, having an open connection with the ocean, where freshwater from inland is mixed with saltwater from the sea. One type of estuary, called a drowned river valley, can be caused by crustal subsidence or a rise in sea level. Chesapeake Bay is one of the largest estuaries of this type in the United States and was formed during the melting of the Pleistocene ice sheets (see Pleistocene epochPleistocene epoch
, 6th epoch of the Cenozoic era of geologic time (see Geologic Timescale, table). According to a classification that considered its deposits to have been formed by the biblical great flood, the epoch was originally called the Quaternary.
..... Click the link for more information.
). Fjordsfjord
or fiord
, steep-sided inlet of the sea characteristic of glaciated regions. Fjords probably resulted from the scouring by glaciers of valleys formed by any of several processes, including faulting and erosion by running water.
..... Click the link for more information.
, or drowned glacial troughs, form similar types of estuaries, particularly in Norway, Alaska, New Zealand, and other glaciated, mountainous coastal regions. Salt marshes and lagoons found behind barrier beaches, such as along the south shore of Long Island, and down faulted sections of the earth's crust, such as San Francisco Bay, are additional types of estuaries. The shape of an estuary affects the height of the tide; some estuaries (such as the Severn and the Bay of Fundy) are characterized by a wavelike tidal borebore,
inrush of water that advances upstream with a wavelike front, caused by the progress of incoming tide from a wide-mouthed bay into its narrower portion. The tidal movement tends to be retarded by friction as it reaches the shallower water and meets the river current; it
..... Click the link for more information.
. Estuaries represent one of the most sensitive and ecologically important habitats on earth. They provide sanctuary for many species of waterfowl, store nutrients for larval and juvenile marine life, and serve as breeding grounds for many desirable species of ocean fish. Since estuaries commonly provide excellent harbors, most of the large ports in the United States (New York, Philadelphia, Baltimore, Mobile, Galveston, Seattle, and San Francisco) are located in estuaries. However, the development of high-density population centers causes deleterious effects that can destroy the very properties of the estuary that made development of the region possible. Human impact on estuaries includes reclamation of tidal land by filling; pollution from sewage, solid waste, industrial effluent, and hot water; increased sedimentation filling the estuary; and alteration of the salinity of estuarine waters by withdrawal or increased influx of freshwater. Increasingly, federal and state governments are passing legislation to protect estuarine environments.

Estuary

 

a single-channel, funnel-shaped seaward end of a river that widens toward the sea. Estuaries form in cases where the sediment carried by the river is removed by sea currents or tidal movements and the adjacent part of the sea is very deep. In such cases no sediment is deposited at the mouth, even if the sediment load is large. The Enisei and the Thames are two of the many rivers that have estuaries.

estuary

[′es·chə ‚wer·ē]
(geography)
A semienclosed coastal body of water which has a free connection with the open sea and within which sea water is measurably diluted with fresh water. Also known as branching bay; drowned river mouth; firth.

estuary

1. the widening channel of a river where it nears the sea, with a mixing of fresh water and salt (tidal) water
2. an inlet of the sea
References in periodicals archive ?
The likelihood ratio test showed that the growth coefficients (k) for female and male fish were significantly different in only one of the four estuaries, i.
It is one of very few estuaries along this coastline that is believed to provide an important role in linking fish populations among Angola, Namibia and South Africa and offers valuable tourism opportunities for communities in the area that can contribute to the long-term economic viability of the region.
Coastal areas are not only home to fragile ecosystems, but they also provide important defenses from hurricane damage," said Jeff Benoit, president & CEO of Restore America's Estuaries, the national leader and coordinator for National Estuaries Week.
Along the Atlantic coast, oysters are generally confined to estuaries, bays, and lagoons, such as Lake Worth Lagoon or the St.
Estuaries and surrounding wetlands act like giant sponges absorbing excess water from floods and storms.
There are five major types of estuaries as classified by their geology: coastal plain, bar-built, deltas, tectonic and fjords.
Our observations support the hypothesis that winter flounder spawning in the Gulf of Maine is not restricted to estuaries.
Importantly, the recent (past 3,300 years) slow rate of sea-level rise was accompanied by sediment accumulation in the form of barrier islands and wetland expansion at the coast that contributed to the geomorphological characteristics of the estuaries (Walker and Coleman, 1987).
Other studies of estuaries or wetlands have reported that annual primary productivity rates based on changes in oxygen levels in the water are often less than the measured respiration rates.
The requested service consists of making the fish inventories beam trawl and fyke nets, eight estuaries of the Loire-Bretagne basin.
On the Pacific coast of North America, estuaries are typically smaller and occur less frequently than in other areas such as the Atlantic coast of North America.
This area here was chosen out of all the estuaries all over the United States to be the first national estuarine research reserve, which says a lot about Oregon and what the politics of that time allowed and supported," Gaskill said.