An estuary is a wide, deep river mouth into the sea, a place where an exchange of fresh water and salt water occurs due to the tides.
Today we talk in depth about the characteristics of estuaries and which 5 are worth not missing.
What is an estuary?
An estuary is a place partially closed in body and formed by the mouth of a river in the sea, The waters of the river flow towards the ocean and the sea, due to the tides it also pushes its water towards the river. This causes an exchange or mixture of salt and fresh water to occur.
The estuary is therefore that transition place between land and sea, between fresh and salt water. Typically, these locations are protected from waves, wind or maritime storms by reefs that act as a barrier and, at the same time, establish the border of the estuary.
San Francisco Bay Estuary
Estuary types
We can find very different from each other in terms of size and shape. According to these two characteristics, they are called in one way or another: lagoon, port, inlet, bay or channel. It is important to know that not everything called a lagoon or port is an estuary. Many lagoons, for example, are not estuaries. How to differentiate it then? If there is exchange of fresh and salt water then it is an estuary, If there is no exchange, it is not.
Within the estuaries we can find different habitats such as shallow or very deep waters, swamps, sandy beaches, mudflats, rocky coasts, mangrove forests, river deltas, etc. These different habitats cause the flora and fauna of the area to vary. To learn more about these habitats, you can read about the types of ecosystems which also influence biodiversity.
Estuaries can house a large quantity and variety of wildlife, among coastal or sea birds, crustaceans, crabs and lobsters, marine mammals, worms or reptiles. Therefore the ecosystems are very different from one estuary to another.
Importance of estuaries
Estuaries are areas where Many species live and are necessary for the survival of these species. We talk about birds, fish, mammals, among others. Migratory birds find estuaries an ideal place to rest on their long journey. For fish and crustaceans they are a safe place to reproduce, in fact, estuaries are sometimes called "sea cradles" because that is where many marine animals are born.
Around the estuaries, there are numerous swamps that are of great importance in another sense. The water arrives drained because it eliminates contaminants, nutrients and sediments. As this water passes through the different swamps, it is purified. In the end the water is much clearer and cleaner, which benefits all species, people, animals, or plants. To better understand the benefits of wetlands, visit our article on wetlands.
Chesapeake Bay Estuary
The numerous plants that can be found in estuaries are beneficial in preventing erosion, protecting against potential flooding, dissipating storm surges and storms. It is interesting to know that some of these plants are considered invasive plants which can alter the balance of the ecosystem if not properly controlled.
In addition to all this, estuaries are a place to learn, observe nature and the animals and plants, places that serve as cultural centers for the nearby communities where they play sports, trade and carry out endless activities.
We must not forget, too, the economic part of estuaries, the ports and docks from which transport or shipping takes place, important as commercial and travel points. An example of this can be seen in the major ports in the world.
Protection of estuaries
Due to all the importance that these places represent, they must be protected from the hand of man, respected and cared for. But, today, there is a major enemy of estuaries and it is climate change. The invasion of alien and invasive species that have proliferated in some estuaries is another important problem that unbalances the ecosystem.
What are the most important estuaries
Some of the well-known estuaries are San Francisco Bay, Puget Canal, Chesapeake Bay, Tampa Bay or Boston Harbor. In the 1990s we can talk about 32 major and large cities worldwide, and twenty-two of them were located in estuaries. Here you can see the importance of those places.
Some of the most important estuaries worldwide are the following:
- La Chesapeake Bay on the eastern coast of the United States
- La San Francisco Bay on the west coast of the United States
- El Thames in Europe
- El Sena in Europe
- El Si-Kiang in Hong Kong
- El Murray in Australia
- The Paraná River and the La Plata River between Argentina and Uruguay.
5 important estuaries in Spain
In Spain there are a total of 93 estuaries, of which it should be highlighted:
1. The estuary Guadalquivir river In Andalucia.
2. The estuary Anllóns River in Galicia.
3. The estuary River Minho shared between the countries of Spain and Portugal.
4. The estuary Guadiaro River In Andalucia.
5. The estuary Ortigueira estuary in Galicia.
