The way whale songs resound from the bottom of the sea could become a useful tool for scientists studying the sediments and rock that form the Earth’s crust, according to new research in the northeast Pacific Ocean.
These tunes are some of the strongest and most extensive vocalizations in the ocean, and with tens of thousands of finely distributed whales around the world, calls could help add to existing scans or even fill gaps where it is more difficult or even dangerous for marine life to use the conventional approach of the air pistol.
Ocean floor seismometers can be used to capture echoes and fluctuations of fine whale calls, revealing the thickness of the crust below, as well as other seismic information useful for scientific research.
(Kuna et al., Science, 2021)
“People in the past have used whale calls to track whales and study whale behavior,” says geophysicist John Nabelek of Oregon State University.
“We thought maybe we could study the Earth using those calls. After every whale call, if you look closely at the seismometer data, there’s an answer from Earth.”
Nabelek and colleagues were studying earthquakes near the Blanco fracture zone off the coast of Oregon, using a network of 54 seismometers, when they observed strong signals on instruments that corresponded to the presence of whales in the area.
Subsequent analysis of six calls showed that underwater songs – which can be as noisy as large ships and can last 10 hours or more – traveled through the ground under the ocean like seismic waves, before being reflected and refracted by ocean sediments. , the basalt layer below, and the lower gabbroic shell just below.
The researchers determined that the structure of these jumping signals could inform estimates of the structure of the oceanic crust: readings calculated from whale signals matched other scientific observations of the area.
“This method extends the use of data already collected,” says Nabelek. “It also shows that the vocalization of animals is useful not only to understand animals, but also to understand their environment.”
More research will be needed to prepare this method for a complete deployment – fine whale songs do not offer as high a scan as other seismic sounding methods, such as air pistols, for example, so they will not completely replace conventional technology.
However, what it could do is give scientists a more detailed look at the oceanic crust and seismic defects that lead to earthquakes and tsunamis. Researchers suggest that songs from other whales, such as sperm whales, could also be used.
Furthermore, machine learning is an option for automating a certain analysis – and using natural whale calls is certainly a less invasive and simpler method than other approaches when it comes to finding out what’s going on under the ocean floor.
“The paper serves as evidence of the concept that could provide new ways to use data from whale calls in research,” says Nabelek. “What I’ve discovered is that whale calls can serve as a complement to traditional methods of passive seismic research.”
The research was published in Science.