Mangroves often sprout in brackish water.
Brackish or brackish water is that with a salinity level between fresh water and sea water. In many places around the world, brackish water appears naturally and forms an important habitat for some unique animal species. However, it can cause environmental damage as it is harmful to organisms that have not adapted to it. This becomes a problem when this water is deliberately cultivated, as is done in some regions to create desirable edible fish. It is also unpleasant to drink and can cause health problems.
Many creatures, like the Florida manatee, have adapted to brackish environments.
The term “brackish” was first used to describe parts of the drinking water table that had been contaminated by salt water in the 1500s. Mixing salt and fresh water created slightly salty water that was not as salty as seawater, but still unpleasant. Many people also noticed that the water was harmful, due to the unique microorganisms that cause human diseases that thrive in it.
Brackish water can be found in some inland lakes such as the Caspian Sea.
In nature, estuaries are common places of brackish water. An estuary is a place where salt water and fresh water mix, usually around the opening of a river. The estuary environment is quite distinctive as it bridges oceans and rivers, hosting unique fish, plants and animals. When the balance of an estuary is disrupted, it can be serious for the animals that live in the area. Many anadromous fish enjoy estuaries because the slow change in salinity allows the fish to get used to it.
Scarlet ibis can be found along estuaries, a common place of brackish water.
Mangroves are also classically salty. Many mangroves are located along shorelines, so there is a salinity transition area that ebbs and flows with the tide. Many fish breed in these swamps, and the unique plants call these regions home. In some regions, mangroves are an important buffer zone between the ocean and land, protecting the land from storm surges caused by hurricanes and tsunamis.
Semi-salt water can also be found in some lakes and inland seas such as the Caspian Sea. The salinity in these lakes and seas can vary depending on water flow and time of year, and they often host a variety of unique animals and plants. It is not uncommon to see stratification in these water bodies, with cold, salty water at the bottom and warmer fresh or brackish water at the top. Each layer hosts different animals, and the disruption of layers can have unfortunate results for the local ecology.