Vertical abundances profiles of the main atmospheric constituents and oxygen species in Uranus (top) and Neptune (bottom). The abundances obtained with the updated chemical scheme (solid lines), and O/H < 45 and 250⊙ for Uranus and Neptune (respectively), are compared to those obtained with the former scheme of Venot et al. (2012) (dotted lines), with <160 and 480⊙ for Uranus and Neptune (respectively). The thermal and abundance profiles are thus not obtained with the same boundary conditions (see text for more details).