Question: what is the difference between marine brackish and freshwater?
Answer: Freshwater contains less than 0.05% salt, or less than 1% salt by some definitions. Brackish water contains less than 3% salt. And saltwater contains more than 3% salt. ... Brackish water is in between, since brackish water is where fresh and saltwater are mixed, especially in estuaries, lakes, and mangroves.