Acoustics

Key Takeaways

Because sound travels far and efficiently through water, understanding how it behaves helps scientists answer fundamental questions about the planet, the ocean, and marine life.
Acoustic tools — from sonar and multibeam bathymetry to Doppler current profilers and hydrophone arrays — map the seafloor, measure currents, and detect animals.
WHOI uses ocean acoustics to study everything from deep-sea eruptions to the movements of endangered whales.

In an ocean where light fades within meters, sound travels for miles — making acoustics one of science’s most powerful tools for probing the sea. WHOI scientists use how sound behaves underwater to map the seafloor, measure currents, and listen for marine life.

What are acoustics?

Acoustics is the science of sound; ocean acoustics attempts to describe how sound behaves in the ocean. A strong understanding of how sound behaves in different conditions beneath the surface of the water or the seafloor helps scientists answer fundamental questions about the planet, the ocean, and marine life.

Sound travels much farther than light through water —in some cases, up to thousands of miles. The speed of sound in the ocean also varies, increasing with increases in temperature, salinity, and pressure (depth). These characteristics make sound an excellent tool to study questions about the physics, chemistry, and biology of the ocean that would be difficult or impossible to approach any other way.

Ocean acoustics can involve detecting and interpreting naturally occurring sounds such as those made by whales and fish or earthquakes, as well as man-made sounds such as those made by ships. Scientists also purposely generate sounds in order to measure ocean currents, track temperature changes over vast areas of the ocean, or measure water depth and map the seafloor. Because sound travels well through solids scientists also use it to probe the structure of sediments and rocks deep beneath the seafloor in order to study such things as the geophysical processes that generate earthquakes, volcanoes, and tsunamis.