Question

Explain the nitrogen cycle in fresh water ecosystem

Answer 1

The first step is the decay of waste products of fish, plants, and invertebrates, along with any dead organisms or uneaten food. As these materials decay, ammonia is produced, which at even low levels will burn the gills of fish and choke off their oxygen supply. Bacteria called Nitrosomonas consume this ammonia and, in the process creating another chemical byproduct called nitrite. Although nitrite is toxic (preventing blood from carrying oxygen), fish can withstand roughly twice the amount of nitrite in their water when compared to ammonia. Next, other bacteria called Nitrobacter consume the nitrite and, in turn, release a less toxic chemical called nitrate. Nitrate requires anaerobic conditions to turn it into harmless nitrogen gas. The parameters needed to create this condition are not commonly present in most aquariums. Hence, water changes are necessary to dilute nitrate.