For the first time, researchers at the University of California, Davis, have demonstrated that forest trees have the ability to tap into nitrogen found in rocks, boosting the trees' growth and their ability to pull more carbon dioxide from the atmosphere.
Given that carbon dioxide is the most important climate-change gas, the nitrogen in rocks could significantly affect how rapidly the earth will warm in the future, the researchers say. They report their findings in the Sept. 1 issue of the scientific journal Nature.
If trees can access more nitrogen than previously thought, that could lead to more storage of carbon on land and less carbon remaining in the atmosphere.
"We were really shocked; everything we've ever thought about the nitrogen cycle and all of the textbook theories have been turned on their heads by these data," said Professor Benjamin Houlton, a biogeochemist and one of the study's co-authors.
"Findings from this study suggest that our climate-change models should not only consider the importance of nitrogen from the atmosphere, but now we also have to start thinking about how rocks may affect climate change," he said.
The importance of nitrogen:
Nitrogen, found in such vital molecules as DNA and protein, is necessary for all life and is used worldwide as a fertilizer for food crops. It is the nutrient that most often limits plant growth in natural ecosystems.
It was previously believed that nitrogen could only enter ecosystems from the atmosphere -- either dissolved in rainwater or biologically "fixed" or assimilated by specialized groups of plants and other organisms. Because the amount of nitrogen in these atmospheric pathways is rather limited, it was thought that most ecosystems could not get enough of this vital nutrient to facilitate plant growth at maximum rates.
Following this line of thought, it was estimated that the nitrogen contribution from
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University of California - Davis