This map is essentially the same as
map00910 Nitrogen metabolism, but an emphasis here is how chemical compounds are transformed as a biogeochemical cycle and how different microorganisms are involved in specific transformation processes represented by KEGG module M numbers. They include: nitrogen fixation [MD:
M00175] of converting atmospheric nitrogen to ammonia by diazotrophs, such as Rhizobium and Klebsiella, nitrification [MD:
M00528 M00804] or oxidation of ammonia to nitrite and nitrate by denitrifying bacteria, such as Nitrosospira, denitrification [MD:
M00529] or reduction of nitrate ultimately to molecular nitrogen by denitrifying bacteria, such as Pseudomonas, dissimilatory nitrate reduction [MD:
M00530] from nitrate to ammonia by many bacteria including Enterobacteria, and annamox [MD:
M00973] or anaerobic ammonium oxidation for conversion of nitrite and ammonium ion directly to molecular nitrogen by certain Planctomycetota. In the nitrogen cycle, eukaryotes are involved only in the energy-consuming assimilatory nitrate reduction [MD:
M00531]. More details of organism groups responsible for each transformation step can be viewed from Taxonomy mapping.