In a small boat off the lush coast of Bali, Indonesia in 2017, marine scientist Rob Williams lowered an underwater microphone called a hydrophone into the blue-green shallows to record something that’s becoming exceedingly rare: an ocean free of human-generated noise.
Williams is one of dozens of scientists around the world involved in what he calls “acoustic prospecting” to map the elusive spots that remain quiet, as well as noisy places that might benefit from practices that can hush the waters. That’s why he carefully tuned in to the subsurface sounds within Bali’s tropical shallows.