Rainfall limit of the N cycle on Earth

Stephanie A. Ewing, Greg Michalski, Mark Thiemens, Richard C. Quinn, Jennifer L. Macalady, Steven Kohl, Scott D. Wankel, Carol Kendall, Christopher P. Mckay, Ronald Amundson

Research output: Contribution to journalArticlepeer-review

61 Scopus citations

Abstract

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 NO3-17O = 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 and and abiotic environment: Mars.

Original languageEnglish (US)
Article numberGB3009
JournalGlobal Biogeochemical Cycles
Volume21
Issue number3
DOIs
StatePublished - Sep 2007

All Science Journal Classification (ASJC) codes

  • Global and Planetary Change
  • Environmental Chemistry
  • Environmental Science(all)
  • Atmospheric Science

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