Geomicrobiology of Nitrogen Flashcards
why is nitrogen so important
it’s an essential nutrient for all life because it has SIX common oxidation states in nature means lots of options for releasing energy via redox reactions
where does inorganic nitrogen occur in nature
- gases, aqueous species, and as solids within organic compounds (solid inorganic forms of N not common)
where does organic Nitrogen form in nature
- organic forms: humic and fulvic acids, proteins, amino acids, purines, pyrimidines, pyridines, other amines, amides
what do microbes do to Nitrogen
- N-fixation
- mineralisation
- immobilisation
- nitrification
- denitrification
what are the four components of the nitrogen cycle
- NH4+ production
- Nitrification (aerobic)
- Denitrification (anaerobic)
- N2 fixation (anaerobic)
what is NH4+ production and where does it occur
- animals excrete urea, bacteria release NH4+
-plants take up NH4+ or NO3- and release NH4+ or organic N (breaks down to NH4+)
Nitrification
oxidation of NH4+ to NO3-
- crucial to providing bioavailable N for plants
Denitrification
Reduction of NO3- to N2
N2 fixation
N2 reduced to NH4+
do denitrification and anammox do
a process that depletes nitrogen from soils and waters because it is volatilized
why dont all organisms do denitrification and anammox
because it requires energy
Most common N2-fixers
-cyanobacteria
-rhizobia
