Nitrogen fixation is a crucial process that transforms atmospheric nitrogen into forms plants can use. Carried out by specialized microorganisms, it's the primary natural source of new nitrogen in ecosystems, contributing 200-300 million metric tons annually.
Symbiotic fixation involves partnerships between microbes and plants, while is performed by free-living organisms. The nitrogenase enzyme complex is key to this process, catalyzing the energy-intensive conversion of N₂ to NH₃ under specific environmental conditions.
Biological Nitrogen Fixation
Biological nitrogen fixation significance
Top images from around the web for Biological nitrogen fixation significance
Frontiers | Ecology of Nitrogen Fixing, Nitrifying, and Denitrifying Microorganisms in Tropical ... View original
Process converting atmospheric nitrogen (N₂) to biologically available forms carried out by specialized microorganisms called transforms N₂ to ammonia (NH₃)
Primary natural source of new nitrogen in terrestrial ecosystems contributes approximately 200-300 million metric tons of nitrogen annually
Reduces dependence on synthetic nitrogen fertilizers improves soil fertility and crop yields (soybeans, alfalfa)
Supports enables colonization of nitrogen-poor environments (arctic tundra, desert soils)
Symbiotic vs non-symbiotic fixation
involves mutualistic relationship between diazotrophs and host plants occurs in specialized structures (nodules) on plant roots (, )
Provides direct nitrogen supply to host plant generally more efficient than non-symbiotic fixation
Non-symbiotic fixation performed by free-living diazotrophs occurs in soil, water, and on plant surfaces (, , )
Fixed nitrogen released into environment less efficient but more widely distributed
Nitrogenase enzyme in fixation
Key enzyme complex catalyzes reduction of N₂ to NH₃ composed of two protein components: