A network of hydrophones studies the seas during a time when they are unusually quiet.
First published in the Daily Maverick 168 weekly newspaper.
Travel and economic slowdowns as a result of the Covid-19 pandemic have combined to put the brakes on shipping, seafloor exploration, and many other human activities in the oceans, creating a unique moment to begin a time-series study of the effects of sound on marine life.
A community of scientists has identified more than 200 non-military ocean hydrophones worldwide and hopes to make the most of the unprecedented opportunity to pool their recorded data into the 2020 quiet ocean assessment and to help monitor the ocean soundscape long into the future. They aim for a total of 500 hydrophones capturing the signals of whales and other marine life while assessing the racket levels of human activity.
Combined with other sea-life monitoring tools and methods such as animal tagging, the work will help to reveal the extent to which noise in "the Anthropocene seas" affects ocean species.
Sound travels a long way in the ocean, and a hydrophone can pick up low-frequency signals from hundreds, even thousands, of kilometres away. The highest concentrations of non-military hydrophones are...