Brackish water is a type of water that has a higher salinity than freshwater but lower salinity than seawater. It typically occurs in areas where freshwater from rivers or streams meets and mixes with saltwater from oceans or seas. This mixture can be found in estuaries, coastal lagoons, and mangrove swamps, making brackish water an important habitat for various species. The salinity of brackish water usually ranges from 0.5 to 30 parts per thousand. This unique environment supports diverse ecosystems, including fish, crustaceans, and wetland plants. Brackish water is crucial for many species' life cycles and serves as a nursery ground for young marine organisms.