Aquatic Science

1. Aquatic Science Brackish Water

2. What is Brackish Water? • Brackish or brack water is water with a level of salinity between freshwater and seawater. • The word comes from the Middle Dutch root "brak," meaning "salten" or "salty". • Because brackish water is hostile to the growth of most terrestrial plant species, without appropriate management it is damaging to the environment

3. How Does Brackish Water Form? • There are several things that cause bodies of brackish water to form, and these bodies of water then became hosts of very unique ecosystems with a variety of plants and animals that only thrive in brackish water environments. • Brackish water occurs naturally where fresh and salt water mix, or where rivers empty into inland lakes. • Certain human activities can produce brackish water, like the building of dikes, and the flooding of coastal marshlands.

4. Salt Concentration • Brackish water is technically defined by it's salinity, or the concentration of dissolved salt in water. • Brine water: Saturated or nearly saturated with salt. • Because brackish water is a mixture of freshwater and salt water, the salt concentrations of brackish water constantly changes. Water salinity based on dissolved salts in parts per thousand (ppt)

5. Mangrove Sources of Brackish Water There are both natural and unnatural sources of brackish water. • Estuaries • Brackish Seas • Brackish Lakes • Fossil Aquifers • Marshes • Mangroves Marsh

6. Mangrove Tree • One of the most common and most easily identifiable plants found in brackish water ecosystems is the mangrove. • There are both white and red mangroves and they use an internal salt filtration system to thrive well in brackish waters. White Mangrove Tree Red Mangrove Tree

7. More Brackish Water Plants • Other plants common in brackish water ecosystems are cattails, mallows, hedge bindweed and a wide variety of grasses. Cattails Mallow Hedge Bindweed

8. Crocodiles • Crocodiles are primarily found in freshwater but some species can also be found in brackish water. • They can tolerate some saltwater, since they have special tongue glands to remove excess salt.

9. Crab-eating Frog • Found in Southeastern Asia • Only known frog that can tolerate salt in their water. • This frog can tolerate marine environments (immersion in sea water for brief periods or brackish water for extended periods) by increasing urea production and retention, and also by remaining slightly hyperosmotic within urea and sodium flux.

10. Diamondback Terrapins • The Diamondback terrapin is the only species of turtle in North America that spends its life in brackish water. • Diamondbacks live in coastal salt marshes, estuaries, and tidal creeks along the U.S.

11. Containing Brackish Water • Most brackish water ecosystems are natural and have existed this way for many years with many species that depend on this range of salinity to survive. • When water is unnaturally transformed into brackish water through rapid human action, it can kill off much of the current ecosystem. • Because of this, water that is purposely made brackish for the purpose of shrimp farming or as a byproduct of reverse electrodialysis or pressure retarded osmosis should be contained to avoid killing off nearby ecosystems.

12. Baltic Sea • The Baltic Sea is the largest brackish body of water in the world. • It became this way because of huge amounts of fresh water runoff along with fresh water from roughly 200 rivers all pouring into the Baltic to make its salinity far lower than the nearby Atlantic Ocean.