Scientists have long used sound to study wildlife. Bird calls, bat echolocation and whale songs, for example, have provided valuable insights for decades. But listening to entire ecosystems is a much newer frontier.
Listening to rivers is especially tricky. Beneath the water is a soundscape of clicks, pops and hums that most of us never hear. Many of these sounds are a mystery. What produces them – an insect? A fish? The water itself?
