These CTD profiles were acquired with the intention of documenting the degassing of Lake Nyos. It was however soon realized that the density profiles showed the rare and unusual patterns of almost homogenised “mixed layers”, which are an indication of double diffusion. The phenomenon was triggered by the subaquatic sources, which release warm salty and CO2-rich water. Motivated by this observation, we continued profiling until the double-diffusive process came to an end. This publication in Environmental Fluid Mechanics presents the documentation of this time-limited unusual phenomenon.