The idea of desert sands that are slightly more ‘alive’ than they seem is no surprise to fans of science fiction. But new research now substantiates this mystical notion: that sand dunes in deserts aren’t just inert masses but carry an ecological relationship with their surroundings. Not only do they grow and move, they also “breathe” water vapor: seemingly inhaling and exhaling moisture from the air.
The research, published in the Journal of Geophysical Research-Earth Surface, has widespread applications: understanding how powdery substances interact with moisture is useful for everything from pharmaceuticals to planetary explorations.
To conduct the research, the study’s lead author, Michel Louge, professor of mechanical and aerospace engineering at Cornell University, used an instrument called capacitance probes — which contain sensors to record minute details on a particular surface.
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The findings were a result of a decades-long project which sought to understand how agricultural soil turns into desert sand. Studying moisture content in sand dunes may provide hints as to how this happens — moreover, it also explains how microbes survive deep in the desert sands despite the heat.
“The wind flows over the dune and as a result creates imbalances in the local pressure, which literally forces air to go into the sand and out of the sand. So, the sand is breathing, like an organism breathes,” Louge said.
Louge’s collaboration with Anthony Hay, associate professor of microbiology at Cornell, showed how the microbes have an important role to play in stabilizing the dunes themselves — preventing them from spilling over as encroachments.
The knowledge that water evaporates even from individual grains of sand can impact how we approach planetary explorations — it is now possible for seemingly arid surfaces to contain trace amounts of water. But the findings also speak to the delicate ecosystem balances that work invisibly — holding ever more secrets about the Earth and how it supports life.
“The future of the Earth, if we continue this way, is a desert,” Louge said.