Nirifying bacteria are autotrophic and are responsible for the conversion of Ammonia to Nitrates. These then produce Nitric Acid. Some of the Species can be particularly troublesome in Cooling systems as they form Zoogloea masses of the organisms embedded in slime. Nitrifying Bacterial species are generally found in Fertilizer Industries where the Ammonia ingress in Water is high. Denitrifying Bacteria work in the reverse way by reducing Nitrates to Nitrites and then to Ammonia. These Bacteria are detrimental to Close Systems where Nitrite based Corrosion Inhibitors are used.