Microbial nitrification and subsequent denitrification releases nitrogen as gas to the atmosphere. Natural processes that generate nitrous oxide may be classified as nitrification and denitrification. Important processes in the nitrogen cycle include fixation, ammonification, nitrification, and denitrification. Bacterioplankton play critical roles in global nitrogen fixation, nitrification, denitrification, remineralisation and methanogenesis. The conventional removal is nitrification, followed by denitrification. And the denitrification is basically the reverse process of nitrification. It is a two-step process, consisting of nitrification followed by denitrification. A 2011 study showed that most of the nitrate removal was due to heterotrophic denitrification. Among the leading products are fuel gas desulfurization and denitrification systems, and ash handling systems. This is less common than denitrification in most ecosystems as a means of nitrate reduction. How do the biogeochemical processes (denitrification, for example) that characterize this system work? Furthermore, nitrous oxide, which is produced during denitrification, attacks the atmospheric ozone layer. Azurins and pseudoazurins participate in the denitrification processes in bacteria. This leads to the ecologically important processes of denitrification, sulfate reduction, and acetogenesis, respectively. They also have a range of environmental impacts, such as denitrification of soil and erosion.