The noisy reef takes us under the waves to the reefs of New Zealand to explore sound and noise under water. Using this unique habitat, we look at what sound is, how it travels, what changes under water and how animals use sound in their world. Find out more about studying sound under water.

A key idea is that animals can use the sounds of the reef to navigate. Fish and crab larvae floating in currents several kilometres from shore need to find their way back to the reef before they settle and metamorphose into the adult form. We know that smell and light are important in this process, but for the first time, scientists in New Zealand have evidence that sound is also used as a navigation tool. Larval crabs are attracted to the sound of a healthy reef and will use this to find their way home.

We also explore what makes a reef such a noisy place. You can probably think of some factors – waves and wind – but the scientists we talk to also listen to kina, shrimp and fish such as John Dory. In the article New Zealand reef noise, learn more about phenomena such as the ‘evening chorus’ – the name for the cacophony of sounds that come from a reef around dusk. Kina make much of this noise, but how do they do it?

The concept of a noisy reef can be used to explore a range of physical concepts including the basics of sound. Scientists like Professor John Montgomery talk about how they use physics as a tool to understand a biological system. It is important that they understand the basics of sound waves, how sound travels through water, how animals hear sound and whether larval animals could actually hear the reef.

Using the idea of the reef and navigation, our resources explore some essential physics ideas relating to sound, but in a whole new way.

Key terms

For explanations of key concepts, see The noisy reef – key terms.


    Published 10 May 2011