Aerobic bacterial pyrite oxidation and acid rock drainage during the Great Oxidation Event

Free oxygen appeared in Earth's atmosphere for the first time around 2.5 billion years ago, in what is known as the Great Oxidation Event, which resulted in profound changes to biogeochemical cycling. Konhauser et al. examine rocks from this time and find that chromium was largely immobile on land until around the Great Oxidation Event, but that within the following 160 million years, it was solubilized on a large scale. The authors suggest that this mobilization was possible only through the action of aerobic, bacterial respiration on abundant supplies of pyrite. This early exploitation of atmospheric oxygen also represents the first record of acid rock drainage.