The Namibian desert is one of the
driest places on the planet. This arid corner of south-west
Africa is characterized by soaring temperatures, harsh winds, and
next to no rain. But even here, life has found a way to harvest that
most precious resource, water.
Perhaps the most innovative means of
obtaining drinking water known in the animal kingdom, the
sequestration of ocean mist has been perfected by the
Namibian Beetle (Stenocara
gracilipes) through
an intricate system of bumps and troughs.
 |
| Stenocara gracilipes. Picture Credit: Moongateclimber/Wikipedia Commons |
Tiny bumps cover the surface
of the beetle’s shell. The bumps are unique in nature in that they
have water attracting tips and water repellant sides. This
combination of hydrophilic and hydrophobic surfaces means that water
can be directed by the beetle’s forewings. By leaning into the
wind, the beetle can catch the vapour and channel it down towards its
mouthparts. The troughs between the bumps have a superhydrophobic
waxy covering, meaning that the droplets roll unavoidably wherever
they are directed. The process is a successful adaptation, with up to
12% of the beetle’s body weight being gained by fog-basking.
Scientists and entrepreneurs
have spotted numerous uses to which this kind of natural technology
can be put. A few of these include:
- Distillation processes
- Dehumidification
- Improved car engines
- Air conditioning
- Freshwater supply generation
So far, these ideas have
remained simply that: ideas. However, some forward-thinking
researchers have, apparently independantly of each other, begun
development of two unique and potentially very useful products.
For instance, in a good example of
biomimicry (the artificial reproduction of naturally-occurring
mechanisms), a type of vapor-harvesting plastic sheeting has been
created by research company QinetiQ. According to Dr Chris Lawrence,
a company spokesperson: ‘What we have learnt from the beetle is an
improved method for condensing liquid from a vapour. We’re
intending that this will be applied to the collection of water for
farming and drinking in arid regions, improvement in distillation
processes and dehumidification for air conditioning and the like.’
Lawrence developed the system in
collaboration with Oxford University zoologist Dr Andrew Parker. The
system involves placing miniscule glass spheres into heated wax to
emulate the hydrophilic peaks and hydrophobic troughs of the beetle’s
shell. During testing, it was found that, by spraying the material
with mist, condensation and thus water harvesting could be achieved
on a large scale. As a further boon, the material is easy to
mass-produce by simply stamping this design onto plastic sheets.
Dr Lawrence said: ‘This would make
fog harvesting several times more efficient than current water
collecting methods.’
The company’s first project will be a
specially designed tent which could be use by people camping in arid
climates to collect drinkable water from the air.
Another company, the start-up NBD Nano,
are developing a water-collecting bottle using the same
biologically-inspired technology. This self-filling vessel, according
to NBD Nano, will be pull three liters of water from the air per
hour, although this will no doubt depend of various environmental
factors, not least of which being air humidity.
Though still only at the developmental
stage for their first product, the small company has other
applications in mind, including potable water for desert projects,
water for greenhouses, and solutions for third world countries in
which access to drinkable water is scarce.
The beetle-back material certainly has
potential. Other uses could include water-harvesting roof tiles and
other buidling materials, automobile paint for self-filling car
tanks, polytunnel sheeting, even clothing that fills a pouch that can
be drunk from whilst walking. The possibile uses for this innovative
adaptation to a pervasive environmental stress could be endless.
References
Briggs, H., 2001. Water Off a Beetle’s
Back. BBC Website.
http://news.bbc.co.uk/2/hi/science/nature/1628477.stm
Accessed 27th December 2014.
Owano, N., 2012. Self-Filling Water
Bottle Takes Cues from Desert Beetle. PhysOrg.
http://phys.org/news/2012-11-self-filling-bottle-cues-beetle.html
Accessed 27th December 2014.
Seely, M. et al., 1983. Fog
response of tenebrionid beetles in the Namib Desert. Journal of Arid
Environments. 6(2): 135-143.
Uncredited, 2014. Water Vapour
Harvesting: Namib Desert Beetle. Biomimicry Institute.
http://www.asknature.org/strategy/dc2127c6d0008a6c7748e4e4474e7aa1#.VJ76IcAB
Accessed 27th December 2014.
Zhai, L. et al., 2006. Patterned
Superhydrophobic Surfaces: Toward a Synthetic Mimic of the Namib
Desert Beetle. Nano Lett. 6(6): 1213-1217.
Top picture credit: Getty Images
This article first appeared on savethewater.org
