Namib desert reveals its water secrets

AS ONE of the driest places on the planet‚ the Namib desert may not seem the obvious place to study the world’s water future.

But it’s exactly the right place for academics from the US and Wits University desert ecologist Mary Seely‚ 77, who has studied the Namib for more than half a century.

The Namib’s fog and dew are the desert’s twin lifelines‚ and “understanding [them] is key to understanding how plants and animals sustain themselves and function under current or future clim ecohydrologists from Indiana state in the journal Science Advances.

The Namib stretches for more than 2 000km along the Atlantic coast between the Olifants River in the Western Cape and the Carunjamba River in Angola. Annual rainfall ranges between 2mm and 200mm‚ and coastal regions are enveloped in thick fog for more than half the year.

But the new study finds that the ocean is not the desert’s only source of moisture.

Non-ocean derived fog accounted for more than half the fog during the year that Lixin Wang and colleagues from Purdue University spent working with Seely in the Namib. Groundwater was the source of more than a quarter of the desert’s fog‚ and “soil water” – derived from rain stored below the surface but located higher than groundwater – was an unexpected source of moisture.

“Knowing exactly where the fog and dew come from will help us predict the availability of non-rainfall water in the future,” said Wang.

“With this knowledge‚ we may be able to determine ways to harvest novel water sources for potential use in waterscarcity situations.”