Sound in the Ocean
WHY IS SOUND IMPORTANT UNDERWATER?
The ocean is full of sounds, from those made by waves and wind to the sounds made by marine animals. Because light can only penetrate so far, many animals rely on sound to navigate their ocean home. As they move about, they may listen for predators, communicate with one another, or even make sound to find food (an ability called ‘echolocation'). Today, we know that marine mammals, fish, and even some invertebrates (e.g. snapping shrimp), use sound in these ways.
Human activities also make sound in the ocean, which can interfere with these important abilities. Imagine trying to have a quiet conversation with someone when there is a loud TV on in the room — it’s not easy to hear or concentrate! If a sound is too loud, it may even harm your ears. Similarly, the sound made by ships and boats can drown out the sounds made by animals, interrupt their activities, and even cause them physical harm. This is why researchers all over the world are seeking ways to reduce the sounds that humans make in the ocean.
HOW CAN WE REDUCE ANTHROPOGENIC NOISE?
In the SATURN project, we're looking at ways to understand and reduce the sound made by ships. Ships create constant sound that can be heard from very far away — even from the ocean floor. We already know that slowing down ships can reduce this 'underwater radiated noise’; but slowing down ships can be complicated when food and products need to be delivered around the world. Another way we can reduce vessel noise is by designing better propellers, where most of the sound comes from. We’re even looking at releasing bubbles around a ships propeller or hull, which creates a ‘curtain' that dampens the sound. From simple solutions to complicated technological ones, there’s a variety of ways we can turn down the volume of human activities and reduce our acoustic impact on the marine environment.
As they move, ships create constant loud sound that can be heard from far away — even as far as the ocean floor. The sounds made by animals are usually intermittent and not as loud or constant. Listen to the calls of three marine mammals and discover how they differ from the sound of a modern container ship.
Recorded with DTAGs off Tenerife by the University of La Laguna, with permits from the Spanish and Canary Islands governments.
Recorded with DTAGs by Aarhus University. You may need to turn your volume up to hear this one.
Recorded on a free-ranging harbour seal using a DTAG by Dominik Nachtsheim (University of Veterinary Medicine Hannover).
Recorded using a Soundtrap noise recorder in the North Sea by Rosalyn Putland (CEFAS), funded by the UK government.
Download a poster about sound!
We created a colourful and engaging poster for student classrooms all about sound, with a focus on the marine environment. The poster introduces concepts such as frequency, amplitude, decibels, and spectrograms, with vibrant but clear illustrations of each. The poster is aimed at secondary school students or older children, but may be useful to other age groups as well.
This resource was developed by Amy Dozier (University College Cork) and Rosalyn Putland (CEFAS).