A possible nitrogen crisis for Archaean life due to reduced nitrogen fixation by lightning

Research areas:
Year:
2001
Authors:
  • R Navarro-Gonzalez
  • CP McKay
  • Delphine Nna Mvondo
Journal:
NATURE
Volume:
412
Number:
6842
Pages:
61-64
Month:
JUL 5
ISSN:
0028-0836
BibTex:
Abstract:
Nitrogen is an essential element for life and is often the limiting
nutrient for terrestrial ecosystems(1,2). As most nitrogen is locked in
the kinetically stable form(3), N-2, in the Earth's atmosphere,
processes that can fix N-2 into biologically available forms-such as
nitrate and ammonia-control the supply of nitrogen for organisms. On the
early Earth, nitrogen is thought to have been fixed abiotically, as
nitric oxide formed during lightning discharge(4-6). The advent of
biological nitrogen fixation suggests that at some point the demand for
fixed nitrogen exceeded the supply from abiotic sources, but the timing
and causes of the onset of biological nitrogen fixation remain
unclear(7-11). Here we report an experimental simulation of nitrogen
fixation by lightning over a range of Hadean (4.5-3.8 Gyr ago) and
Archaean (3.8-2.5 Gyr ago) atmospheric compositions, from predominantly
carbon dioxide to predominantly dinitrogen (but always without oxygen).
We infer that, as atmospheric CO2 decreased over the Archaean period,
the production of nitric oxide from lightning discharge decreased by two
orders of magnitude until about 2.2 Gyr. After this time, the rise in
oxygen (or methane) concentrations probably initiated other abiotic
sources of nitrogen. Although the temporary reduction in nitric oxide
production may have lasted for only 100 Myr or less, this was
potentially long enough to cause an ecological crisis that triggered the
development of biological nitrogen fixation.