Study conducted on 100-year-old sessile oaks in Barbeau forest, France. Four sampling campaigns from February to September 2008. Four tree compartments analyzed: leaves, twigs, trunk, and roots
Nitrogen fixation converts atmospheric nitrogen into reactive compounds like ammonia. More than 90% of nitrogen fixation occurs through soil microorganisms. Free-living bacteria like cyanobacteria fix nitrogen in soil. Symbiotic bacteria like Rhizobium form nodules in leguminous plants
Nitrogen cycle converts nitrogen into various forms in ecosystems. Atmospheric nitrogen makes up 78% of Earth's atmosphere. Nitrogen fixation converts atmospheric nitrogen to usable forms. Plants absorb nitrogen through root hairs, converting it to usable forms
Nitrification is the biological oxidation of ammonia to nitrate via nitrite. Process occurs in two steps: ammonia oxidation to nitrite and nitrite oxidation to nitrate. Aerobic process performed by bacteria and archaea. Ammonia-oxidizing bacteria (AOB) and archaea (AOA) are main participants
Nitrogen fixation converts atmospheric dinitrogen (N2) to ammonia (NH3). Lightning produces NOx, which can be converted to usable nitric acid. Cyanobacteria fix nitrogen in both terrestrial and aquatic environments. Some plants form symbiotic relationships with nitrogen-fixing bacteria
Nitrogen cycle transforms atmospheric nitrogen into usable forms for living organisms. Nitrogen exists in both organic and inorganic forms. Process involves fixation, nitrification, assimilation, ammonification and denitrification