Nature Reviews Microbiology (2018) https://doi.org/10.1038/s41579-018-0087-z Published online 24 September 2018

In Figure  3, ‘Candidatus Scalindua’ and Thaumarchaeota were erroneously shown to produce nitrous oxide (N2O). As neither group directly produces N2O, the arrows and products have been removed both online and in the pdf. The authors apologize for any confusion caused.