Nature Microbiology 1, 16002 (2016); published online 15 February 2016; corrected 7 March 2016.

Subsequent to this work being published it was discovered that 3 (out of 67) of the scaffolds (totaling 93 kb) in one of the Hadesarchaea bins (YNP_45) are actually contaminants. Table 1 has been modified to reflect the removal of these scaffolds. The presence of these contaminating sequences does not alter the major conclusions drawn; the carbon fixation, hydrogen and CO oxidation pathways as well as proteins used for phylogenetic analyses are not included in the contaminants. However, one of the nitrite reductases (c552) mentioned in the paper is on one of them (the other nitrite reductase (in bin YNP_N21) is not). Accordingly, the main text and Figure 3 have been modified to remove reference to c552 and Supplementary Figure 7 has been removed. The relevant sequences have been removed from Genbank.