Chemical abundance in the atmosphere at t = 10 Myr and different disc viscosities α = 1, 5 and 10 × 10⁻⁴ (top to bottom). The different colours show the different configurations and the different markers show the given planet. The markers for the single planet cases are larger. For the elements C, O, and N the abundances are given in the number ratio to hydrogen normalised by the stellar value while C/O is computed using (C/H)/(O/H) normalised by the stellar value. For the exact numbers see Table D.1.