Biogeochemistry

6.

The Global Nitrogen Cycle

6.1.

Nitrogen Reservoirs

6.1.1.

Atmospheric Nitrogen

6.1.1.1.

6.1.1.2.

6.1.1.3.

Nitrogen Oxides

6.1.1.4.

6.1.2.

Terrestrial Nitrogen

6.1.2.1.

Soil Organic Nitrogen

6.1.2.1.1.

Protein-bound Nitrogen

6.1.2.1.2.

Nucleic Acid Nitrogen

6.1.2.1.3.

Chitin and Other Forms

6.1.2.2.

Soil Inorganic Nitrogen

6.1.2.2.1.

6.1.2.2.2.

6.1.2.2.3.

6.1.2.3.

6.1.2.3.1.

6.1.2.3.2.

6.1.2.3.3.

6.1.2.4.

Microbial Nitrogen

6.1.2.4.1.

Bacterial Biomass

6.1.2.4.2.

6.1.3.

Aquatic Nitrogen

6.1.3.1.

Dissolved Inorganic Nitrogen

6.1.3.1.1.

6.1.3.1.2.

6.1.3.1.3.

6.1.3.2.

Dissolved Organic Nitrogen

6.1.3.2.1.

6.1.3.2.2.

6.1.3.2.3.

6.1.3.3.

Particulate Nitrogen

6.1.3.3.1.

6.1.3.3.2.

6.2.

Nitrogen Transformations

6.2.1.

Nitrogen Fixation

6.2.1.1.

Biological Fixation

6.2.1.1.1.

Symbiotic Fixation

6.2.1.1.1.1.

Rhizobia-Legume Symbiosis

6.2.1.1.1.2.

Actinorrhizal Symbiosis

6.2.1.1.1.3.

Cyanobacteria Symbiosis

6.2.1.1.2.

Free-living Fixation

6.2.1.1.2.1.

6.2.1.1.2.2.

Aquatic Cyanobacteria

6.2.1.1.3.

Nitrogenase Enzyme

6.2.1.1.3.1.

Structure and Function

6.2.1.1.3.2.

Environmental Controls

6.2.1.2.

Industrial Fixation

6.2.1.2.1.

Haber-Bosch Process

6.2.1.2.2.

Global Production

6.2.1.3.

Atmospheric Fixation

6.2.1.3.1.

6.2.1.3.2.

Photochemical Processes

6.2.2.

6.2.2.1.

Depolymerization

6.2.2.2.

6.2.2.3.

Environmental Controls

6.2.2.3.1.

6.2.2.3.2.

6.2.2.3.3.

6.2.2.3.4.

Substrate Quality

6.2.3.

6.2.3.1.

Ammonia Oxidation

6.2.3.1.1.

Ammonia-oxidizing Bacteria

6.2.3.1.2.

Ammonia-oxidizing Archaea

6.2.3.2.

Nitrite Oxidation

6.2.3.2.1.

Nitrite-oxidizing Bacteria

6.2.3.3.

Environmental Controls

6.2.3.3.1.

6.2.3.3.2.

Temperature Effects

6.2.3.3.3.

Inhibition Factors

6.2.4.

Denitrification

6.2.4.1.

Sequential Reduction Steps

6.2.4.1.1.

Nitrate to Nitrite

6.2.4.1.2.

Nitrite to Nitric Oxide

6.2.4.1.3.

Nitric Oxide to Nitrous Oxide

6.2.4.1.4.

Nitrous Oxide to Nitrogen Gas

6.2.4.2.

Environmental Controls

6.2.4.2.1.

Oxygen Availability

6.2.4.2.2.

Carbon Availability

6.2.4.2.3.

6.2.4.3.

Denitrifying Organisms

6.2.5.

6.2.5.1.

Process Description

6.2.5.2.

Anammox Bacteria

6.2.5.3.

Environmental Significance

6.2.6.

6.2.6.1.

6.2.6.1.1.

Ammonium Uptake

6.2.6.1.2.

6.2.6.1.3.

Organic Nitrogen Uptake

6.2.6.2.

Microbial Immobilization

6.2.6.2.1.

Competition with Plants

6.2.6.2.2.

C:N Ratio Effects

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