Focus sur la fin de la période humide africaine en Éthiopie centrale (5,5 ka BP) par l'analyse détaillée de diatomées fossiles

[Departement_IRSTEA]Eaux [TR1_IRSTEA]QUASARE [ADD1_IRSTEA]Adaptation des territoires au changement globalInternational audienceThe termination of the African Humid Period in northern Africa has been described as abrupt, occurring within centuries, as well as gradual, in response to incremental decreases in summer insolation. This study examined the rapidity of the change in diatom assemblages over the period from 6.5 to 4.5 cal ka BP, in a core studied previously at a coarser resolution. This transition was characterized by high variability of assemblages, which could be related, in part, to changes in water conductivity, and potentially enhanced by a site-specific hydrological threshold or ecological salinity threshold. We hypothesize that the variations in diatom assemblages reflect climate fluctuations, which may have been an early warning signal of an impending climate regime shift