Some of the loudest sounds in the ocean are air guns, fired by ships doing seismic studies of the seafloor.

The blasts can interfere with the communication of whales for a thousand miles around. So, scientists thought, what if they could use whales to do the studies instead?

In a seismic study, sound waves from a ship travel down through the water, through the ocean floor and into the geologic layers below.

They reflect off these layers and bounce back to other ships, where powerful computers analyze them to build geologic models of the Earth below the ocean.

The songs of fin whales, when converted from water to air, are as loud as a jet leaving an aircraft carrier, but in a similar low range as the air guns.

Scientists used hydrophones on the seafloor to record the whale song and its reflections, then fed that data through the same seismic computer programs.

Turns out the whale song did in fact penetrate the subsurface, down to about 8,000 feet, and could successfully be used to build similar geologic models.

Scientists now plan to analyze the higher-frequency songs of other whales, seals and dolphins to see if they can add detail to the models.

Air guns are still louder and penetrate deeper, so whale song won’t replace seismic ships for critical study.

But recording and analyzing the songs of sea mammals could allow geologic studies where seismic ships are too expensive or impractical.