Nickel Famine May Have Led To Life On Earth | April 13, 2009 Issue - Vol. 87 Issue 15 | Chemical & Engineering News
Volume 87 Issue 15 | p. 45 | Concentrates
Issue Date: April 13, 2009

Nickel Famine May Have Led To Life On Earth

Iron shortage may have given oxygen-producing bacteria an edge over their methane-making cousins
Department: Science & Technology
Banded iron formations, such as these found in Ontario, show chemical features of having formed in iron-rich oceans billions of years ago.
Credit: Stefan Lalonde
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Banded iron formations, such as these found in Ontario, show chemical features of having formed in iron-rich oceans billions of years ago.
Credit: Stefan Lalonde

The evolution of complex life-forms on Earth, from parakeets to panthers, could occur only after oxygen gas appeared in our atmosphere more than 2 billion years ago. But scientists have long debated how oxygen-producing bacteria could have gained dominance over methane-producing bacteria, and in so doing, taken control of the composition of primordial Earth's air. Now, a team of researchers led by Kurt O. Konhauser, a biogeochemist at the University of Alberta, in Edmonton, report evidence that this turning point in the history of life on Earth may be rooted in an ancient nickel famine (Nature 2009, 458, 750). In particular, the team found that the nickel-to-iron ratio in ancient rocks dropped around 2.7 billion years ago. Because methane-producing bacteria rely heavily on nickel for many of their essential enzymes, a deficiency of the metal could have decreased the metabolism and populations of methane makers, giving oxygen-evolving microbes the necessary edge. "If a single geological change can starve a major microbial community, and thereby change the trajectory of life on Earth, it suggests that there is a fragility to Earth's elemental cycles that we are only beginning to uncover," notes Mak A. Saito of Woods Hole Oceanographic Institution, in a commentary that accompanies the report.

 
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