Mystery of Earth's Missing Nitrogen Solved

Scientists have discovered a previously unknown environmental source of the element

By Doug Main on May 29, 2018



Sedimentary rocks, such as those in the Grand Canyon, contain surprisingly high levels
of nitrogen. Credit: Paul Rojas Getty Images

Experts used to think nearly all nitrogen in soil came directly from the atmosphere, sequestered by microbes or dissolved in rain. But it turns out scientists have been overlooking another major source of this element, which is crucial to plant growth: up to a quarter of the nitrogen in soil and plants seeps out of bedrock, according to a study published in April in Science.

Apart from a few scattered studies, “the [research] community never thought to look at the rocks,” says lead study author Benjamin Z. Houlton, a global ecologist at the University of California, Davis. This discovery has implications beyond understanding the planet’s nitrogen cycle; it could also alter climate models. It suggests plants in certain areas may be able to grow faster and larger than previously thought and could thus absorb more carbon dioxide, Houlton says.

As global temperatures rise, calculating how much heat-trapping carbon dioxide plants soak up is becoming increasingly important. The exact amount remains uncertain, but Houlton notes that plants could provide “a little bit more of a cushion ... to store our carbon pollution.”

More:
https://www.scientificamerican.com/article/mystery-of-earths-missing-nitrogen-solved/