Rainfall limit of the N cycle on Earth

Global Biogeochemical Cycles
By: , and 



In most climates on Earth, biological processes control soil N. In the Atacama Desert of Chile, aridity severely limits biology, and soils accumulate atmospheric NO3. We examined this apparent transformation of the soil N cycle using a series of ancient Atacama Desert soils (>2 My) that vary in rainfall (21 to <2 mm yr−1). With decreasing rainfall, soil organic C decreases to 0.3 kg C m−2 and biological activity becomes minimal, while soil NO3 and organic N increase to 4 kg N m−2 and 1.4 kg N m−2, respectively. Atmospheric NO3 (Δ17O = 23.0‰) increases from 39% to 80% of total soil NO3 as rainfall decreases. These soils capture the transition from a steady state, biologically mediated soil N cycle to a dominantly abiotic, transient state of slowly accumulating atmospheric N. This transition suggests that oxidized soil N may be present in an even more arid and abiotic environment: Mars.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Rainfall limit of the N cycle on Earth
Series title Global Biogeochemical Cycles
DOI 10.1029/2006GB002838
Volume 21
Issue 3
Year Published 2007
Language English
Publisher American Geophysical Union
Contributing office(s) Toxic Substances Hydrology Program
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Global Biogeochemical Cycles
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