Denitrifying bacteria are microorganisms that convert nitrates in soil into free atmospheric nitrogen, depleting the soil of fertility and reducing agricultural productivity, as described by Encyclopedia Britannica. Among the known or suspected denitrifying bacteria are Thiobacillus denitrificans, Micrococcus denitrificans and some species of Serratia, Pseudomonas and Achromobacter.
Denitrifying bacteria are actors in the nitrogen cycle, which causes nitrogen compounds to circulate through nature, according to Encyclopedia Britannica. Nitrogen is essential to sustaining life on Earth. Though nitrogen forms 78 percent of Earth's atmosphere by volume, it remains unavailable until converted into a plant-usable form through a series of microbiotic transformations. Plants then absorb the nitrogen into their bodies as they grow. Whether plants are consumed by animals or man, or whether they decay, the nitrogen contained in plants continues through the cycle. The complete nitrogen cycle consists of nitrogen fixation, nitrogen assimilation, ammonification, nitrification and denitrification, although not necessarily in that order. According to the American Society of Microbiology, scientists are researching denitrifying bacteria's possible role in climate change, as the release of too much nitrous oxide into the atmosphere disturbs the balance of the nitrogen cycle.