The Nitrogen Cycle - AP Environmental Science

Ammonia ($NH_3$). Direct product of nitrogen fixation by bacterial nitrogenase.

Increased crop yields. Synthetic fertilizers dramatically boost agricultural productivity.

Ammonification. Bacterial decomposition converts organic nitrogen to inorganic forms.

Acid rain formation. Nitrogen oxides react with water to form nitric acid.

Nitrogen fixation. Converts inert atmospheric $N_2$ into reactive compounds.

Nitrogen fixation. High energy electrical discharge breaks $N_2$ bonds naturally.

Assimilation. Plants absorb nitrogen compounds through their root systems.

Nitrification. First oxidation step in the two-stage nitrification process.

Fertilizer production. Industrial Haber-Bosch process creates synthetic nitrogen compounds.

Nitrates ($NO_3^-$). Highly soluble and mobile form preferred by most plants.

Nitrifying bacteria. First step in two-stage nitrification process.

Nitrogen gas ($N_2$). Returns nitrogen to atmosphere, completing the cycle.

Nitrogenase. Catalyzes the energy-intensive conversion of $N_2$ to $NH_3$.

Ammonium nitrate. Common synthetic fertilizer providing readily available nitrogen.

Nitrogen-fixing bacteria. Contain nitrogenase enzyme that converts $N_2$ to $NH_3$.

$NH_3$. Product of nitrogen fixation with one nitrogen and three hydrogens.

Nitrous oxide ($N_2O$). Potent greenhouse gas with 300 times warming potential of $CO_2$.

Denitrification. Anaerobic bacteria reduce nitrates, completing the nitrogen cycle.

Water pollution. Runoff causes eutrophication and groundwater contamination.

Denitrification. Requires oxygen-free environment for bacteria to function.

Ammonia ($NH_3$). Direct product of nitrogen fixation by bacterial nitrogenase.

$N_2O$. Two nitrogen atoms bonded to one oxygen atom.

Host nitrogen-fixing bacteria. Provide shelter and nutrients for nitrogen-fixing bacteria.

Convert $N_2$ to ammonia. Use nitrogenase to break triple bonds in atmospheric nitrogen.

Increased crop yields. Synthetic fertilizers dramatically boost agricultural productivity.

Nitrogen gas ($N_2$). Completes the nitrogen cycle by returning to atmosphere.

Cyanobacteria. Blue-green algae that fix nitrogen in marine environments.

Nitrification. First step in nitrification where ammonia becomes nitrite.

Nitrogen fixation. Breaks the strong triple bond in $N_2$ to create bioavailable forms.