Rocking urchins provide the soundwaves

SydneyMorningHerald.com.au: Rocking urchins provide the soundwaves
Rocking urchins provide the soundwaves Nicky Phillips
May 9, 2011


Ocean ambience... natalie Soars is studying sounds made by Australian sea urchins. Photo: Nick Moir

IF WHALES are the lead singers of the ocean, sea urchins are the back-up vocalists.

While it may surprise some that these spiky marine creatures make noise, a Sydney marine biologist plans to measure the contribution they make to the soundscape of the sea.

Natalie Soars, a PhD candidate at the University of Sydney, said sea urchins produced a loud clicking noise as they fed or scraped up against rocks.

Advertisement: Story continues below ''You can hear it when you snorkel near them.''

Scientists have only recently discovered the sounds produced by urchins and other marine animals were a vital part of the ocean's ecology.

''Fish and coral larvae can hear, and fish and crab larvae listen to sounds to find the reef and where to settle.''

But little is known about the composition of ambient sea noise and what species contribute to it, she said.

And while it was clear the noises made by boats could drown out sea sounds, it was unknown if these interruptions affected the sea creatures who rely on sound for direction.

While research in New Zealand has found certain species of sea urchin are an important part of the background sea noise, the contribution made by a common Australian species, Centrostephanus rodgersii, which is found in large numbers along the south-eastern coast, is unknown.

The first part of Ms Soars' research will be to study the sea urchins in captivity.

''In isolation we can figure out the sounds they make and the frequencies,'' said Ms Soars, who has been awarded a research scholarship by the Sydney Institute of Marine Science.

The data will be used to identify sea urchin sounds within recordings of ambient sea noise collected at locations in Sydney Harbour and Jervis Bay.