When these algae die, bacteria decompose them, and use up oxygen. This process is called eutrophication . Dissolved oxygen concentrations can drop too low for fish to breathe, leading to fish kills. Ammonia Ammonia, another inorganic form of nitrogen, is the least stable form of nitrogen in water. Ammonia is easily transformed to nitrate in waters that contain oxygen and can be transformed to nitrogen gas in waters that are low in oxygen.
Total ammonia is the sum of ammonium and unionized ammonia.
The dominant form depends on the pH and temperature of the water. This makes the equation above move left, increasing the amount of aqueous NH 3 . Toxic concentrations of ammonia in humans may cause loss of equilibrium, convulsions, coma, and death. There are many ways of measuring nitrogen forms. Total nitrogen can be determined by adding chemicals to convert all of the nitrogen forms in a sample to nitrate, and then measuring nitrate concentration.