Ecological consequences of early Late Pleistocene megadroughts in tropical Africa

• Published in: Proceedings of the National Academy of Sciences - PNAS 2007-10, Vol.104 (42), p.16422-16427
• Main Authors: Cohen, Andrew S, Stone, Jeffery R, Beuning, Kristina R.M, Park, Lisa E, Reinthal, Peter N, Dettman, David, Scholz, Christopher A, Johnson, Thomas C, King, John W, Talbot, Michael R, Brown, Erik T, Ivory, Sarah J
• Format: Article
• Language: English
• Subjects: Africa; Air Conditioning; Animals; Biodiversity; Biological Sciences; Diatoms; Disasters; Drought; Ecology; Fishes; Fossils; Fresh Water; Freshwater; Geologic Sediments; Geological time; Humans; Humidity; Hypotheses; Lake water; Lakes; Lentic systems; Paleoecology; Paleontology; Physical Sciences; Pisces; Pollen; Population; Principal components analysis; Taxa; Tropical Climate; Watersheds
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.0703873104

Extremely arid conditions in tropical Africa occurred in several discrete episodes between 135 and 90 ka, as demonstrated by lake core and seismic records from multiple basins [Scholz CA, Johnson TC, Cohen AS, King JW, Peck J, Overpeck JT, Talbot MR, Brown ET, Kalindekafe L, Amoako PYO, et al. (2007) Proc Natl Acad Sci USA 104:16416-16421]. This resulted in extraordinarily low lake levels, even in Africa's deepest lakes. On the basis of well dated paleoecological records from Lake Malawi, which reflect both local and regional conditions, we show that this aridity had severe consequences for terrestrial and aquatic ecosystems. During the most arid phase, there was extremely low pollen production and limited charred-particle deposition, indicating insufficient vegetation to maintain substantial fires, and the Lake Malawi watershed experienced cool, semidesert conditions (