Polyphenols are generally toxic to microorganisms. In peatlands, scientists thought microorganisms avoided this toxicity by degrading polyphenols using an oxygen-dependent enzyme, and thus that low-oxygen conditions inhibit microbes' carbon cycling. However, a new study found that Arctic peatland microorganisms used alternative enzymes, with and without oxygen, to break down polyphenols. This suggests carbon stored in these ecosystems is more at risk than previously thought.