is a specific kind of: H2O, water.

is a broader term that covers: red tide.

contains: atomic number 35, Br, bromine | atomic number 53, I, iodin, iodine | atomic number 19, K, potassium | atomic number 11, Na, sodium | common salt, sodium chloride | calcium chloride | evaporite.

is the opposite of: fresh water, freshwater.

derivation: brine | brackish, briny.