Lakes of Ounianga

World Heritage Research

Discover scientific research and academic studies that deepen our understanding of Lakes of Ounianga from its history and significance to its conservation, management, and contemporary challenges.

• A predominantly tropical influence on late Holocene hydroclimate variation in the hyperarid central Sahara

  A new lake sediment record from Ounianga Serir oasis reveals that the central Sahara experienced hyperaridity more extreme than today around 4200 years ago. The hypersaline terminal lake, sustained by fossil groundwater inflow, remained stable throughout the late Holocene but exhibited sensitivity to local rainfall and evaporation variations. Geochemical proxies indicate that century-scale hydroclimate changes in this region were primarily driven by tropical West African monsoon intensity, with shorter-term fluctuations influenced by midlatitude Atlantic Ocean circulation shifts.

  Van der Meeren, T., Verschuren, D., Sylvestre, F., Nassour, Y. A., Naudts, E. L., Aguilar Ortiz, L. E., Deschamps, P., Tachikawa, K., Bard, E., Schuster, M., & Abderamane, M. (2022). A predominantly tropical influence on late Holocene hydroclimate variation in the hyperarid central Sahara. Science Advances, 8(14). https://doi.org/10.1126/sciadv.abk1261

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• Staurophora ouniangaensis sp. nov. (Bacillariophyceae, Anomoeoneidaceae), a new diatom from the Ounianga Lakes in the Sahara, Chad

  Researchers have identified and described a new species of diatom, Staurophora ouniangaensis, from the saline waters of the Ounianga Lakes in Chad's Sahara. This discovery, based on detailed microscopic observations, highlights the unique morphological traits of the species, including its valve outline and slightly twisted frustules. The study also distinguishes it from a similar species, Cymbella obtusa, by its finer stria density. Notably, Staurophora ouniangaensis supports the preference of this genus for inland saline environments, as it thrives in mesosaline to hypersaline waters within these lakes.

  RIRONGARTI, R., COCQUYT, C., PAILLÈS, C., & SYLVESTRE, F. (2022). Staurophora ouniangaensis sp. nov. (Bacillariophyceae, Anomoeoneidaceae), a new diatom from the Ounianga Lakes in the Sahara, Chad. Phytotaxa, 558(1), 103–115. https://doi.org/10.11646/phytotaxa.558.1.7

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• High Prevalence of Urinary Schistosomiasis in a Desert Population: Results from an Exploratory Study Around the Ounianga Lakes in Chad

  A high prevalence of urinary schistosomiasis, reaching nearly 40%, was discovered among populations living around the UNESCO World Heritage Site of Ounianga Lakes in Chad. This finding challenges the assumption that such water-borne diseases are limited to tropical regions, highlighting significant public health risks even in desert environments. The study employed a cross-sectional survey, focus group discussions, and environmental sampling to detect Schistosoma haematobium and S. mansoni, confirming infections through molecular genetics and identifying intermediate host snails (Bulinus truncatus) that facilitate local transmission. While S. mansoni infections were detected, the absence of its intermediate hosts suggests limited relevance. Qualitative data underscored the morbidity burden of urinary schistosomiasis and the lack of access to diagnostics or treatment in this remote region, emphasizing the need for tailored interventions.

  Moser, W., Batil, A. A., Ott, R., Abderamane, M., Clements, R., Wampfler, R., Poppert, S., Steinmann, P., Allan, F., & Greter, H. (2021). High Prevalence of Urinary Schistosomiasis in a Desert Population: Results from an Exploratory Study Around the Ounianga Lakes in Chad. https://doi.org/10.21203/rs.3.rs-1016632/v1

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• A new cichlid fish in the Sahara: The Ounianga Serir lakes (Chad), a biodiversity hotspot in the desert

  A previously undescribed cichlid fish, Astatotilapia tchadensis, has been discovered in Lake Boukou, part of the Ounianga Serir lakes in Chad, a UNESCO-listed desert landscape. This new species, characterized by distinctive features such as black bars, orange spots on its anal fin, and unique pharyngeal dentition, highlights the remarkable biodiversity of these lakes, which are sustained by subsurface groundwater inflow. The discovery underscores the Ounianga Serir lakes as a critical hotspot for vertebrate diversity in one of the world's most arid regions, with at least six fish species belonging to three families thriving in this extreme environment.

  Trape, S. (2016). A new cichlid fish in the Sahara: The Ounianga Serir lakes (Chad), a biodiversity hotspot in the desert. Comptes Rendus. Biologies, 339(11-12), 529–536. https://doi.org/10.1016/j.crvi.2016.08.003

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• Varved sediments of Lake Yoa (Ounianga Kebir, Chad) reveal progressive drying of the Sahara during the last 6100 years

  A 6100-year sediment record from Lake Yoa, part of the UNESCO World Heritage Site Lakes of Ounianga in Chad, reveals a progressive drying trend in the eastern Central Sahara. The study, utilizing high-resolution sedimentological and geochemical analyses, including X-ray fluorescence core scanning, demonstrates that decreasing monsoon rainfall combined with strong evaporation transformed the once hydrologically open and fresh lake into its current hypersaline state, which has persisted for about the last 1050 years. The data also indicate a gradual increase in aeolian input, supporting the notion of a progressive rather than abrupt transition from a humid to an arid Sahara during the Mid to Late Holocene.

  Francus, P., von Suchodoletz, H., Dietze, M., Donner, R. V., Bouchard, F., Roy, A.-J., Fagot, M., Verschuren, D., & Kröpelin, S. (2013). Varved sediments of Lake Yoa (Ounianga Kebir, Chad) reveal progressive drying of the Sahara during the last 6100 years. Sedimentology, 60(4), 911–934. Portico. https://doi.org/10.1111/j.1365-3091.2012.01370.x

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• Modern and early Holocene mollusc fauna of the Ounianga lakes (northern Chad): implications for the palaeohydrology of the central Sahara

  A rich early Holocene mollusc fauna, including a new species (Gabbiella ouniangaensis), was discovered at the Ounianga lakes in northern Chad, suggesting these lakes were hydrologically isolated during that period. The modern mollusc community is impoverished and likely resulted from recent colonization events after the eradication of the early Holocene fauna due to high salinity or desiccation. The study analyzed fossil molluscs from diatomaceous limestone outcrops at Ounianga Serir, comparing them with other Saharan lake sites to infer past hydrological conditions in the central Sahara.

  Van Bocxlaer, B., Verschuren, D., Schettler, G., & Kröpelin, S. (2011). Modern and early Holocene mollusc fauna of the Ounianga lakes (northern Chad): implications for the palaeohydrology of the central Sahara. Journal of Quaternary Science, 26(4), 433–447. Portico. https://doi.org/10.1002/jqs.1469

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