Brett Smith for redOrbit.com
Despite widespread use of fertilizers and nitrogen emissions by industrial processes, the amount of atmospheric nitrogen has remained consistent over the past 500 years, according to a new study in Nature.
“People have been really interested in nitrogen in current times because it’s a major pollutant,” said study co-author Kendra McLauchlan, an assistant professor of geography at Kansas State University. “Humans are producing a lot more nitrogen than in the past for use as crop fertilizer, and there is concern because excess levels can cause damage. The mystery, though, is whether the biosphere is able to soak up this extra nitrogen and what that means for the future.”
About 15,000 years ago, many glaciers and ice sheets began to melt as the Earth entered a global warming period. As temperatures rose, the Earth experienced an 8,000-year decline in nitrogen availability as both carbon and nitrogen became locked up in newly exposed soils. According to researchers, the interactions between the nitrogen cycle and the carbon cycle during this time period could be important in understanding the climate of the near future.
“What happened in the past might be a dry run for Earth’s future,” said co-author Joseph Craine, a research assistant professor in biology. “By looking at what happened millennia ago, we can see what controlled and prevented changes in nitrogen availability. This helps us understand and predict how things will change in the future.”
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