An unlikely creature could help tackle water scarcity

Scientists are turning to beetles and science fiction for clues to harvest water from fog.

Namib desert beetle

Water is something many of us take for granted — but for more than 1 in 10 people around the world, access to clean water isn’t a given. The United States Centers for Disease Control and Prevention estimates 780 million people do not have access to safe drinking water. Industries also suffer from water scarcity — agriculture is both a victim and a cause of water shortages, for example.

As the world’s population grows and demand rises, the need for sustainable sources of water is so dire that some think it will soon cause wars. In the last decade, 466 conflicts around the world involved water, according to the Pacific Institute. And, as the climate warms, the problem will only get worse, the United Nations predicts.

Scientists are working towards innovative solutions to water scarcity — turning to both science fiction and unlikely creatures for inspiration.

What Star Wars and beetles have in common

Fog harvesting — a technology similar to the moisture farms used on the desert planet Tatooine in Star Wars — has the potential to provide fresh water in certain areas on Earth, scientists say.

In places like Chile and Morocco, which are both located near coasts where fog is abundant, some people are already harvesting water from fog, the researchers said. The way the technology works is this: Water particles land on mesh screens and drip down into a receptacle. The vapor collides with the screens just as it would tree leaves swaying in the breeze. Then, the water travels via pipes to the communities that need it.

It’s an effective technique: A single screen can produce up to 53 gallons of fresh water per day, according to the researchers.

This week, researchers at the annual meeting of the American Physical Society presented new findings that may improve upon the model. Rather than mimic the way trees gather water from the air, the researchers draw their inspiration from a more unlikely source: beetles.

Namib desert beetles do some water collecting of their own. They even have a “fog-basking stance,” said Fan Kiat Chan, a graduate student at the University of Illinois at Urbana-Champaign. Chan made the comments during a press conference on Monday.

The beetle “collects water on its back and drinks from there,” Chan explained. (For anyone who is curious, here are some more bizarre beetle behavior facts.)

Namib Desert Darkling Beetle or Stenocara Gracilipes
The Namib desert beetle traps drinking water with distinct bumps and ridges on its back. 

It may be this special stance — a kind of a crouched headstand — that helps the beetle gather fog, he said. But Chan and his team discovered that the bumps and ridges on the beetle’s back have something to do with it, too.

The researchers looked at different types of beetle backs: smooth, bumps, dimples, ridges, grooves. “We wanted to know if these bumps are doing something locally to the flow,” Chan said.

A lesson in fluid mechanics, from beetles

When it comes to fog water collection, the mechanisms at play fall broadly into two parts. The first is “collision and deposition,” and is shaped by the motion of water droplets. The second is “drainage and transport,” which depends on the chemical properties of the water itself.

Most researchers have focused on the second part — what to do with the water once it’s been collected. Instead, Chan’s team paid attention to the first — collision and deposition.

The experiment was intended to investigate the basic science behind fluid mechanics, Chan said, not as a study designed to solve the problem of water scarcity. But if we can understand why and how animals like the Namib desert beetle collect water, it may allow scientists to create better fog-trapping technology.

Taking notes from beetles could mean creating smaller fog collection systems. The screens are large — around 40 square meters. “What if you don’t have that amount of space at your expense?” Chan asked.

In the future, engineers might be able to mimic the dimpled backs of the bugs to make more compact and efficient fog collectors, or even portable systems, the researchers suggest.