Most of our atmosphere is nitrogen, an absolutely necessary element for all living things. It's required for DNA, the genetic material that serves as the blueprint for an organism, and for proteins. Enzymes, substances responsible for mediating most chemical reactions in the body, are proteins, as are the building blocks of muscles and other tissues.
Yes, nitrogen is abundant—nevertheless, it is one of the elements that limits plant growth in our desert. The problem is that we can't use the nitrogen in the air. Its two atoms form a molecule that we are unable to break apart to use. It's much like the lament of sailors—water, water everywhere, and nary a drop to drink.
We have only two natural sources. The energy of lightning can split the
molecules to form new materials, and a group of bacteria is able to split the bond.
These bacteria commonly live in nodules on the roots of plants of the bean family, such
as mesquites and acacias—one reason that these leguminous plants are so common in the
Chihuahuan Desert.
Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.
Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.
A short version of the Nitrogen Cycle.