Monday, September 02, 2024

Why biologists are listening to soil — and what it’s telling them

Researchers searched for sounds produced by ants, worms and other creatures underground, soundscapes studied in the emerging field of ecoacoustics.


By Erin Blakemore
September 1, 2024 


Healthy soil is surprisingly noisy, a new analysis suggests — and researchers are listening for clues on the cacophony’s link to biodiversity.

To better assess the links between soil sounds and biodiversity, researchers looked at — and listened to — a variety of landscapes in South Australia. They were searching for sounds produced by ants, worms and other creatures underground, soundscapes studied in the emerging field of ecoacoustics.

Writing in the Journal of Applied Ecology, researchers describe experiments with three different types of temperate forest sites: two deforested plots of land maintained by regular mowing, two woodland plots that had been restored in recent years and two mostly undisturbed plots of land.

The researchers recorded soil sounds during daytime hours at all six sites, supplementing the data with recordings of soil samples taken in a soundproofed chamber. They counted the number of invertebrates in each soil sample to determine how much diversity could be found beneath each site.

The analysis showed more diversity in both the untouched and restored plots — and both had more complex acoustics. Recordings of the soils on those plots featured clicks, bubbling and a range of other sounds — evidence of the variety and health of life beneath the Earth’s surface. The deforested plot was quieter and had less abundant life inside than the more vegetated land.

Listening to the soil could one day help identify areas in need of restoration or protection, or even warn of environmental disturbances, the researchers write, adding that the technology could be used to identify invasive species and biosecurity risks like fire ants.


“All living organisms produce sounds, and our preliminary results suggest different soil organisms make different sound profiles depending on their activity, shape, appendages and size,” Jake M. Robinson, an ecologist and researcher at Flinders University in Australia and the study’s first author, said in a news release.

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