Nature 437, 336–342 (2005)

It has been drawn to our attention (by J. A. Fuhrman) that Fig. 2 contains a citation error. Specifically, the citation associated with “Discovery of planktonic marine archaea” in Fig. 2 that was incorrectly given as ref. 20 should instead be ref. 21 (Fuhrman, J. A., McCallum, K. & Davis, A. A. Nature 356, 148–149; 1992).