In this section, we will learn how are estuaries formed and the different types of estuaries. Where do we usually find estuaries? So let’s find out the answer. A mixture of freshwater and saltwater can also be called as brackish water and its salinity can range from 0.5 to 35 ppt.
Where do we Usually Find Estuaries?
Content Summery
An estuary is basically an area where a freshwater or stream meets the ocean or sea or body of salty water. They are vital to the ecosystems that encompass them. They also account for much of the surrounding economies. We need to maintain all estuaries and we must inform ourselves of them as much as possible.
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Types of Estuaries
There are 4 main types of Estuaries.
- Coastal plain Estuary
The Coastal plain Estuary results from a changr in sea levels that causes an ocean to move into an already existing river vally. Coastal plain Estuary are usually large, wedge shaped on the inner part, and broadening and deepening on the outer sied ( seaward).
Some examples include..
- Florida Bay (United States)
- Chesapeake Bay (United States)
- Bar-Built Estuary
These estuaries are shallow, and are separated from the sea by sabd bars that run parallel to the coast. The strea s that flow through these estuaries usually have a low water volume, witch riskes the chance of the estuary being permanently blocked due to sandbars growing onto barriervbeaches or islands.
For examples….
- Barnegat Bay, New Jersey
- Pamlico Sound, N.Carolina
- The Fjord Estuary
Fjords are deeply eroded valleys that were once formed by glaciers. They are sometimes U-shaped. They usually have steep sides, rock bottoms, and underwater sills. They are also shallow at the mouth. Some examples include…….
- Sognefjord, Norway
- The Tectonic Estuary
These estuaries are made by geologic faulting/folding. After the tectonic event occurs, land near the ocean lowers and is filled by Rivers that feed into the area.
For examples….
- San Fransisco Bay, california.
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How Are Estuaries Formed Simple? Similarities and Differences
Each type of the estuary is different ways that a body of freshwater meets an ocean or saltwater.
Organisms living within these estuaries need to have special aadaptationsto adjust to the differentiating salinity levels, different tides, and different predators daily.
But, all of these types have been made in unique ways and therefore are shaped in unique ways.
Coastal plaine estuaries are formed by rising sea levels due to melting ice during the ice ages. The water merged into lower coastal river valleys.
Bar build estuaries occure when sandbars or islands are build by ocean waves and currents near coastal areas connecting to one or more rivers or streams.
Fjord estuaries are created by advancing glaciers. These glaciers leave deep channels carved into the earth, with an opening to the ocean.
Tectonic estuaries are formed by a rapid movement of the earth’s crust, creating a depression or basin. This typically occurs near fault lines during earthquakes. The depression will sink below sea level, and ocean water will rush in to fill it. These depressions can connect to freshwater areas, creating a tectonic estuary.
