Lockdown is Reducing Ocean Noise: the Silence is Benefitting Marine Life Immensely
In some cities, coronavirus pandemic lockdowns have offered some respite to the natural world. Urban areas are experiencing clearer skies and the return of wildlife to waterways. Recent evidence of a significant drop in underwater noise pollution has led experts to predict that the crisis may also be good news for whales and other sea mammals.
Planes remain grounded, ships stay anchored, and cars sit parked as people hunker down at home. The world has come to a halt as it grapples with COVID-19, and the consequential silence is touching all corners of the earth. It’s likely that in April 2020 humans created the least amount of sound since the start of the Industrial Revolution.
The effects of this silence already rippling through the ocean—but they won’t last long, argues marine acoustician Michelle Fournet, “We get this window, we get a snapshot into life without humans. And then when we come rushing back, that window will close. It’s really an important time to listen.”
These times are reminiscent of the days following the terrorist attacks of 9/11, when everything was unusually silent, almost eerily so. The movement of people and goods through the air and across the oceans dwindled out of fear and uncertainty. The tragedy of 9/11 and its aftermath also presented a rare opportunity—not too dissimilar to today’s silence—to study how human activity, or lack thereof, was affecting some of the most endangered animals on the planet.
While the world was still in shock following the attacks, researcher Manuel Castellote decided to set off to study the social behavior of North Atlantic right whales. Castellote found something he wasn’t expecting: the recent absence of ship noise had caused the noise environment to change drastically overnight.
Researchers were able to study the whales in a stunningly quiet environment, which would’ve been nearly impossible under most circumstances. The resulting data was a huge milestone in regards to understanding the link between noise pollution and whales. Through combining analyses of collected whale droppings and underwater recordings, Parks and her colleagues determined that ship noise is correlated with stress in whales.
Now that worldwide trade and movement have slowed, the oceans have gone quiet again. Barclay and fellow researchers have been studying how much change has occurred in the underwater noise environment over the past few months. Scrutinizing sound signals from underwater observatories on the seafloor off British Columbia, Barclay found a notable drop in the amount of low-frequency sound. Sound in the 100-hertz range dropped to around 1.5 decibels, roughly a 25% reduction in power. “A lot of the larger whales [including Baleen, Humpback and grey whales] use sound in this range,” Barclay says.
Another marine life researcher, Fournet, studies humpback whales in Southeast Alaska, where cruise ships have polluted the underwater soundscape for decades. In Southeast Alaska, entire generations of whales have never experienced a single quiet day in their feeding grounds. Now, Fournet says, “we can learn something not just about how these animals respond to noise, but about how these animals communicate at all.”
Noise affects whales’ ability to echolocate: a whales’ hunting success depends in part on their ability to hear the faint echo of a sound bouncing off salmon that could be 100 meters away. That sensitive process requires at least some modicum of quiet in the environment, Ford says, something whales are less likely to get in busy or noisy waters. Bioacoustics researcher Chloe Malinka says there is evidence to suggest that, “in many instances, they just completely stop echolocating, or they change their foraging behavior.” Sometimes whales stop hunting altogether, these behavioral changes interfering with the health and survival of these animals.
The reduction in marine noise and the resulting behavior of marine mammals has yet to be fully understood, but what is known so far appears to indicate a noise environment that’s somewhat closer to what the oceans would have sounded like 150 years ago. The effect of that quieter ocean would likely be healthier marine mammals: hunting would become easier, mating more convenient, and wayfinding more obvious.
Furthermore, turning down the volume would protect many more species beyond whales. A 2017 study found that zooplankton can be killed by high-intensity noises, while tens of thousands of fish species who use sound to communicate can become extremely disoriented or stressed due to an increase in ocean noise. With humans’ limited knowledge of marine life, a full understanding of how a quieter ocean could protect and benefit underwater life isn’t fully known. However, Jasny argues, “It shouldn’t take a human calamity to achieve those benefits.”
Fournet says the “snapshot” of silence occurring right now is a chance to hear how the pre-industrial world sounded, and observe the extent to which relative quiet affects marine life and behavior, as well as any other broader effects. “It’s not going to be the saving grace of nature,” she says. “What’s going to be the saving grace of nature is when we take that snapshot and we blow it up to poster size and we share it with the world, and people realize what kind of an impact we have.”
A few questions we should ask ourselves is what kind of world do we want to return to once the pandemic has passed? Are we going to rebuild the economy with the same unsustainable and destructive practices? Or will we take this opportunity to build a greener and more sustainable economy? Our daily financial decisions can either help to transform our economy or preserve the status quo. The way that we spend and invest has a massive impact on the future of the environment. As an investor, you have the agency to choose firms that are concerned with the health of our planet and its many life forms, companies that raise the bar through their ethical commitments and standards.
Let’s transform our economy into one that aids in the health of the ocean and the marine animals who live within it. Our active support will yield benefits for years to come.