Nitrogen glut: Too much of a good thing is deadly for the biosphere
| Abbreviations in this article CBD UN Convention on Biological Diversity. CO2 carbon dioxide. N nitrogen. N2 dinitrogen (inert nitrogen gas). N2O nitrous oxide. NH3 ammonia. NO, NO2, NOx nitrous oxides. NO3 nitrate. Nr reactive nitrogen. O3 ozone. P phosphorous. PM particulate matter |
Part Two of Ian Angus’s examination of the disruption of the global nitrogen cycle by an economic system that values profits more than life itself.
Part One: Nitrogen Crisis: A neglected threat to Earth’s life support systems
Part One of this article outlined how the metabolic activity of specialized bacteria in soil and oceans drives the nitrogen cycle, by “fixing” inert nitrogen from the air into reactive nitrogen, converting it to forms that plants can use, and eventually returning it to the atmosphere.
As scientists from Germany’s Max Planck Institute explain, the “microbial nitrogen-cycling network” maintained a consistent level of reactive nitrogen in the global biosphere for billions of years.
“There is an astonishing diversity of microorganisms that transform nitrogen, and each of these microorganisms has discrete physiological requirements for optimal growth. As growth conditions in nature are highly variable and seldom optimal, nitrogen turnover by individual microorganisms is bound to be inefficient. However, nitrogen transformations in the environment are carried out by microbial communities that recycle nitrogen more efficiently than single microorganisms. Consequently, very little bioavailable nitrogen escapes to the atmosphere, and the small amount lost as dinitrogen gas is balanced by nitrogen fixation.”[1]
That vital cycle was disrupted in 19th Century Europe, when cities grew so large that the nitrogen and other nutrients consumed in food by the urban population could not return to the land, causing pollution in the cities and reducing soil fertility in the countryside.[2]
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