For centuries, the thinking has been that all the nitrogen available for plant growth worldwide comes from the atmosphere. But a new study by National Science Foundation (NSF)-funded researchers at the University of California (UC), Davis, shows that more than a quarter of that nitrogen is derived from the weathering of Earth’s bedrock.
The findings show that rock weathering is a globally significant source of nitrogen to soils and ecosystems, according to co-author and team leader Ben Houlton of UC Davis. “That runs counter to the centuries-long paradigm that has laid the foundation for the environmental sciences,” said Houlton.
Geology and Carbon Sequestration
Rock-derived nitrogen may fuel the growth of forests and grasslands, and allow them to sequester more carbon dioxide than previously thought. Mapping the nutrient profiles in rocks for their carbon uptake potential could help drive conservation efforts, the researcher.
The work also helps solve the “case of the missing nitrogen”. For decades, scientists have recognized that more nitrogen accumulates in soils and plants that can be explained by input from the atmosphere alone, but researchers couldn’t pinpoint what was missing.
In previous work, Houlton and Morford analyzed rocks collected from the Klamath Mountains in northern California and found that the rocks and the surrounding trees contained large amounts of nitrogen.
In the current study, they built on that work, analyzing the entire planet’s nitrogen balance; the scientists developed a model to assess rock nitrogen availability on a global scale.