How the Namib Desert Beetle Could Help Solve Our Water Crisis
- Two-thirds of the world’s population face extreme water scarcity at least one month a year. Many of these places are dry, arid deserts without a reliable source of fresh water – other than fog, that is.
- But catching the fog isn’t as easy as you might think, at least for us humans.
- The Namib Desert beetle, on the other hand, practically perfected the art.
- Here’s how scientists are creating technology based on the beetle exoskeleton that could help end the water scarcity.
Here is a transcript of the video.
Narrator: Here is a riddle for you, a man stands in the desert. He is thirsty, withered and surrounded by fresh water, but he cannot drink. Why? He is surrounded by fog. It’s not really a conundrum, it’s a real problem that scientists have been trying to solve for years. And the solution might just be this little beetle. It might not sound like much, but it can pull water out of the air.
Two-thirds of Earth’s inhabitants face extreme water scarcity at least one month a year. Half a billion do not have enough water all year round. And those numbers are only expected to increase as climate change takes its toll. But what many of these areas lack in traditional water sources, they make up for with fog, like the Namib Desert. It is one of the oldest and driest places in the world. Depending on how far you are from the coast, precipitation averages about half an inch to two inches per year. But this is what we would consider a foggy desert, a place where fog is the main source of water for plant and animal life, like the Namib Desert beetle.
At first glance, this group of beetles seems to be really bad at capturing fog. It’s small, it’s round, and our current fog collecting technology is nothing like it. Fog meshes are currently based on leaves and blades of grass, and their effectiveness is determined by this complicated formula. Where these two basically confirm that fast winds, large droplets, and thin targets over a large area are the best conditions for collecting. And this represents the capacity of the mesh to drain the droplets collected in a reservoir without becoming clogged.
So by the formula, the Namib Desert beetle shouldn’t be able to do what it does. Since, you know, beetles are not made of mesh. And yet, when the fog sets in, the beetle climbs to the top of a dune and the fog basks, leaning towards the wind. Water droplets collect on his back and roll up to his mouth. As simple as it sounds, it’s literally like trying to grab a cloud and stare at it.
Hunter King: If you wave your fingers through the mist, you don’t just see a path where your fingers were and all the water collected. It just flows with air, through them.
Narrator: But the beetle manages to do what we cannot. The secret lies in its exoskeleton. And it really is a secret.
King: We are still far from it, or we are approaching it.
Narrator: A lot of research has been done on how water moves to the beetle’s mouth, but almost none has covered how the droplets get there in the first place. Hunter King and his team tried to find the answer, but encountered an unexpected bump in the road. The original beetle that scientists first started looking for had exactly that, bumps on its exoskeleton. And these bumps have been theorized to impact the efficiency of fog collection. Corn…
King: It turns out that the beetle that has the bumps is not one of the beetles that bathe in the fog.
Narrator: King and his team still decided to go ahead with their experiment. In the lab, they 3D printed spheres and cylinders with various surface textures, smooth, ridged, and bumpy. They then put the spheres in a misty wind tunnel. It turns out that the sphere with one-millimeter bumps captured the fog 2.5 times better than the smooth sphere.
King: If you add ridges that are maybe a bit like the beetle we found is the basker fog, you go up to something like a factor of two, so it’s still not small.
Narrator: Other research in partnership with experts in computational fluid dynamics at the University of Illinois has come even closer. They developed a computer model that tested the ability of droplets to strike a surface. The tiny water droplets have very little inertia and must squeeze a film of air before they make contact. The model found that the less the squeezed droplets had to do, the harder they hit the surface, which you should get with rougher textures. These little details are important in harnessing and recreating these properties in a usable technology.
King: If we understand the beetle game, then we can play it differently for greater effect.
Narrator: Even a slight increase in efficiency could improve the lives of people who depend on current fog-catching technology. And we’re not just talking about drinking water here, catching the fog can open the doors to agriculture, allowing people to raise more crops and livestock. Identifying these properties is one thing. But once scientists are able to exploit them, engineers should be able to design all kinds of fog collectors. Autonomous fog collection structures, of course. But they could also use the material to cover existing objects to turn anything into a fog collector.
King: There have been proposals to modify the tents, say for refugee camps, if we were to say that these tents are going to be in a place where there is enough wind blown fog then you might make bumps in it. the surface.
Narrator: The discovery of King’s semi-accidental bump and the still-unknown qualities of the fog-bathing beetle might help solve the riddle, giving this man in the wilderness a better way to drink. And, potentially, end the water scarcity for good.
EDITOR’S NOTE: This video was originally posted in August 2020.