Water From Air
Part of the Water: H2O = Life exhibition.
Part of the Water: H2O = Life exhibition.
Nearly every continent on Earth has a few places in which an unusual phenomenon takes place: An arid coastal region is blanketed daily by dense fog coming in off the ocean. Organisms in some of those places--plants, animals, and humans--have developed ingenious ways to extract liquid water from fog.
Some beetles in the Namib Desert in southwestern Africa, such as Onymacris unguicularis, trap and drink water from the fog. To get a drink, these beetles wait for fog to roll in from the ocean. Climbing to the top of sand dunes, they raise their back legs and tilt into the wind. The fog condenses into water droplets on bumps on the beetles' backs. When the drops become large and heavy enough, they roll into the insects' mouthparts.
Fabric, stretched between two poles, is used for fog catching in Chile. A square meter of net (about 11 square feet) can produce up to 14 liters (nearly four gallons) a day.
The Atacama Desert in northern Chile is one of the driest places on Earth. Villagers in the region--fishermen, miners, and their families--generally don't have access to piped water, so they must buy trucked-in water at high prices. Fog-catching nets, such as the one being installed here, can provide an inexpensive alternative water source.
Between the Atacama Desert and Chile's capital, Santiago, there was once an extensive high-altitude forest. There, plants relied on moisture from the clouds captured by the leaves of tall trees. When those trees were cut, the water supply vanished. Today, foresters are replanting trees and installing fog-catching nets to water them. When the trees are tall enough to trap fog on their own, foresters move the nets to another area and plant more trees.