The Dry Sahara

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05/09/2008

May. 09, 2008

The Dry Sahara

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What made the Sahara Desert go dry -- and is there any water there left to be found? Writing in the journal Science, a team of researchers reports this week that they believe that the drying of the Sahara was not a sudden event, but rather took place over some 6000 years. The researchers looked at sediment samples taken from cores drilled in the bottom of Lake Yoa, one of the Sahara's few remaining lakes. The sediment layers at the bottom of the lake show a gradual change, the researchers say, involving a gradual reduction in the abundance of tropical vegetation, followed by the loss of grass cover, and the eventual establishment of the modern desert plant community. Arid conditions similar to those today were in place as much as 2700 years ago, the team found. We'll talk with one of the authors of the controversial study, which counters several previous findings indicating a more sudden change in conditions in the Sahara. We'll also talk about whether the ancient waters of the Sahara remain hidden under the desert -- and, if so, what can be done to locate them.

Produced by Karin Vergoth