“Sound is a tangible way of connecting to aspects of nature that are hidden from humans. The deep ocean, the dark night, and now the dense earth beneath our feet,” writes Ella Browning. And you can hear underground for yourself in the fascinating recordings she includes in her essay on earthworm “munching.” In this emerging field of soil ecoacoustics, researchers—including Browning—are finding links between ecosystem recovery and the character of underground soundscapes. Healthy soil literally sounds different. This piece will change how you view the ground beneath your feet.

A core principle of ecoacoustics is that complexly noisy natural places are healthier natural places. This means that it’s not just the volume of noise, but the diversity of sound that indicates habitat health. The dawn chorus in an intact Bornean tropical forest is magical in its complexity, especially if you’re lucky to experience it mixed in with the whoops of a troop of gibbons swinging through overhead, as I was during a visit in 2019.

In contrast, cities are generally not ecologically healthy and, while they are incredibly noisy places, they are filled with the harsh, more monotonous sounds of car engines and other machines, and often little biotic sound. Soundscapes dominated by anthropogenic sounds have been linked to poor mental health in people, whereas the opposite has been found for natural sounds like birdsong or forest soundscapes.