Ammonia reaches the pond water as a by-product of metabolism by animals and by decomposition of organic matter by bacteria. The toxicity of ammonia nitrogen is attributed mainly to unionized form. As the concentration in water increases ammonia excretion by aquatic organism diminishes and levels of ammonia in blood other tissues increases. The result is an elevation in blood pH and adverse effects on enzyme catalyzed reactions and membrane stability. Ammonia increases oxygen consumption by tissues, damages gills and reduces the ability of blood to transport oxygen. |