Limnology of Sahara Desert
Prof. dr. Anton Brancelj
National Institute of Biology
"The heart of Sahara" is volcanic area on the south-most part of Algeria, where sandy desert turns into hard-rock plateau at the elevation of c. 1600 m. It has volcanic origin but nowadays it is mainly characterised by silicate sandstone. In contrast to common opinion, the area, which is positioned in the very centre of Sahara, is rich in surface water bodies. Contemporary precipitations in Tammanrasset are quite modest and temperatures are high (less than 100 mm of rain per year at the temperatures of about 36-40C). However, on the Mouydir Plateau, which is about 300 km north of Tammanrasset, even in May could be found rather big and relatively cold pools of surface water. Those pools support relatively rich and diverse aquatic and terrestrial fauna and flora, including 20-30 cm long fish. Pools, named "guelta", are in fact remnants of the rivers and are completely different from artesian wells supporting life in oases. Tenths of square kilometres of dried-out bottoms of the lakes and several hundreds metres wide river beds, filled with huge boulders, give landscape its characteristic aspect. They are indicators of much more wet conditions in the past. Numerous graves and wall paintings additionally give evidence on extent of human population about 5000 years ago on a shore of nowadays dried-out lakes. Information on expedition, including some data on ground-water fauna found there, will be presented during a seminar.