Data

The finely laminated sediment record of a permanent, hypersaline, desert oasis lake in the Ounianga region of northeastern Chad presents a unique opportunity to document the hydrological evolution of this groundwater-fed aquatic ecosystem during mid- and late-Holocene desiccation of the Sahara. In this study we reconstruct long-term changes in zoobenthos and zooplankton communities of Lake Yoa as their early-Holocene freshwater habitat changed into the hypersaline conditions prevailing today. Chironomid...

The Lake Yoa record and archaeological data provide adequate evidence that mid-Holocene aridification did not occur abruptly across all of North Africa. Modeling results on the issue of abrupt versus gradual desiccation of the Sahara are sufficiently diverse that paleoecological data from a continuous natural archive can usefully guide the evaluation of model parameters responsible for this diversity.

Lake Yoa (19.03°N, 20.31°E, 380 m a.s.l.) is a groundwater-fed lake in the hyperarid eastern Sahara halfway between the Tibesti Mountains and the Ennedi plateau. Kröpelin et al. (2008) revealed that the bottom sediments contain a unique archive of climatic and environmental change in the Earth´s major desert. The 7.5 m sediment record of OUNIK03/04 which covers 6,100 years has been extended to a maximum drill depth of 15.7 m during a 2010 coring campaign within the framework of the Collaborative...

Große Wasserflächen inmitten der Wüste sind nicht nur ein Naturspektakel, sondern auch ein hochpräzises Umweltarchiv. Die aus ihnen gewonnenen Sedimente dokumentieren die Klimaentwicklung und geben Aufschluss über Staubstürme, Savannenbrände und Vulkanausbrüche. Eine Reise in den Nordosten des Tschad. Von Stefan Kröpelin

The fresh and saline lakes of Ounianga Kebir and Serir in northeastern Chad are among the very few permanent aquatic ecosystems currently existing in the hyper-arid core of the Sahara desert. The confirmed modern fauna of aquatic molluscs at Ounianga comprises three widespread species (Melanoides tuberculata, Biomphalaria pfeifferi and Lymnaea natalensis), of which only the first appears to maintain a thriving population. We recovered seven more species of gastropods, among which one is new to science...