Although nitrogen is essential for all living organisms — it makes up 3% of the human body — and comprises 78% of Earth’s atmosphere, it’s almost ironically difficult for plants and natural systems to access it.
Atmospheric nitrogen is not directly usable by most living things. In nature, specialized microbes in soils and bodies of water convert nitrogen into ammonia — a crucial form of nitrogen that life can easily access — through a process called nitrogen fixation. In agriculture, soybeans and other legumes that facilitate nitrogen fixation can be planted to restore soil fertility.
An additional obstacle in the process of making nitrogen available to the plants and ecosystems that rely on it is that microbial nitrogen “fixers” incorporate a complex protein called nitrogenase that contains a metal-rich core. Existing research has focused on nitrogenases containing a specific metal, molybdenum.
The extremely small amount of molybdenum found in soil, however, has raised concerns about the natural limits of nitrogen fixation on land. Scientists have wondered what restrictions the scarcity of molybdenum places on nature’s capacity to restore ecosystem fertility in the wake of human-made disturbances, or as people increasingly search for arable land to feed a growing population.
Read more at Princeton University
Photo Credit: Marie Renaudin