Inert majority
N2's triple bond locks most nitrogen out of proteins until a specialist opens it.
N2 is everywhere and almost useless until nitrogenase or a factory reduces it. The rest of the cycle is a set of redox jobs.
Rhizobium in clover nodules, Nitrosomonas in soils, and anammox bacteria in wastewater are different actors, not one germ.
Traits
Nitrogenase club
Only some bacteria and archaea hold the enzyme. Oxygen is a problem for it — hence nodules and thick slime.
Redox ladder
Ammonia, nitrite, nitrate and N2 are rungs microbes climb for electrons.
Industrial twin
Haber-Bosch rivals biology in annual flux. That is why the cycle now has a human chapter.
Greenhouse leak
N2O escapes from incomplete denitrification and some nitrification.
No human pathogen plot
The cycle is planetary metabolism, not an infection story.
Once you see the cycle, fertilizer is not magic powder — it is a human shove on a microbial road.
Keep exploring
More in Beneficial allies
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Familiarity 48