,The aim of this project is a paleoecological reconstruction of the environmental history of the central Sahara desert since the last ice age, using fossil remains of aquatic biota preserved in the continous sedimentary record of Lake Yoa in northern Chad. This includesstudies of the taxonomy and biogeography of the midge (Chironomidae) fauna of the Sahara, and of the modern limnology, biodiversity and ecology of aquatic ecosystems in the Ounianga lake district.