By Dave Chambers
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 for academics from the US and Wits University desert ecologist Mary Seely, 77, who has studied the Namib for more than 50 years, it is exactly the right place.
That’s because 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 climates”, the ecohydrologists write in the journal Science Advances.
The Namib stretches for more than 2000km along the Atlantic Coast. Annual rainfall ranges between 2mm and 200mm, and the Namib’s coastal regions are enveloped in thick fog for more than half the year.
The new study, however, finds that the ocean is not the desert’s only source of moisture.
“Surprisingly, non-ocean derived fog accounted for more than half of total fog events” over the year.
Groundwater was the source of more than 25% of the fog, and “soil water” – stored below the surface – was an unexpected source of moisture.
Said Purdue University’s Lixin Wang: “Knowing exactly where the fog and dew come from will help us to predict the availability of non-rainfall water in the future, both in the Namib and elsewhere.
“We may be able to harvest novel water sources.
“Even in the driest places, minor components of the water cycle are critical to keeping the environment alive.”
Confidente. Lifting the Lid. Copyright © 2015