Ammonium (NH4+)

Ammonium (NH₄⁺) — or its uncharged form ammonia (NH₃) — is a form of nitrogen which aquatic plants can absorb and incorporate into proteins, amino acids, and other molecules. High concentrations of ammonium can enhance the growth of algae and aquatic plants. Bacteria can also convert high ammonium to nitrate (NO₃^-) in the process of nitrification, which lowers dissolved oxygen.