According to new research conducted in the northeast Pacific Ocean, the way fin whale songs resonate from the seabed could become a useful tool for scientists studying sediment and rock that they form the earth’s crust.
These songs are some of the loudest and most powerful vocalizations in the ocean, and with tens of thousands of fin whales scattered around the world, calls could help add to existing explorations or even fill gaps where it is more difficult or even dangerous for marine life to use the conventional approach of air cannons.
Ocean bottom seismometers can be used to capture the echoes and fluctuations of fin whale calls, revealing the thickness of the crust below, as well as other seismic information that is useful for scientific research.
(Kuna et al., Science, 2021)
“People in the past used whale calls to track whales and study the behavior of whales,” says geophysicist John Nabelek of Oregon State University.
“We thought maybe we could study the Earth using these calls. After each whale call, if we look closely at the seismometer data, there will be an answer from the Earth.”
Nabelek and colleagues were studying earthquakes near the White Fracture Zone off the coast of Oregon, using a 54-meter seismometer, when they noticed strong signals on instruments corresponding to the presence of whales in the area.
A subsequent analysis of six calls revealed that underwater songs, which can be as loud as large ships, and can last ten hours or more, traveled across the ocean floor like seismic waves, before being reflected and refracted by sediments. oceanic. the lower basalt layer, and the lower gabbroic crust even further down.
The researchers determined that the composition of these bounce signals can inform estimates of the structure of the oceanic crust: readings calculated from whale signals coincided with other scientific observations in the area.
“This method expands the use of data that is already being collected,” says Nabelek. “It also shows that animal vocalizations are useful not only for understanding animals, but also for understanding their environment.”
More research will be required to prepare this method for its full deployment: fine whale songs do not offer as high-resolution scanning as other seismic survey methods such as the air gun, for example, so they will not completely replace them. conventional technology.
However, what they could do is give scientists a more detailed look at the oceanic crust and the seismic faults that lead to earthquakes and tsunamis. Researchers suggest that songs from other whales, such as the sperm whale, could also be used.
Later, machine learning is one of the options for automating some of these analyzes; and the use of natural whales is certainly a less invasive and simple method than other approaches to figuring out what’s going on under the ocean floor.
“The paper serves as proof of the concept that it could provide new avenues for using whale data in research,” says Nabelek. “What we discovered is that whale calls can serve as a complement to traditional methods of passive seismic research.”
The research has been published in Science.