Wild weather whipped the ocean into what resembled more a cappuccino than the beach at Yamba on North Coast at the weekend.Stormy conditions at the time whipped up the foam, which consists of masses of tiny bubbles. John Dengate of the NSW Department of Environment explained that the foam was formed from the remains of organic material such as plankton and seaweed that had been pulverized on rocks. An entry about sea foam published in the Q & A section of the New York Times offers are more detailed explanation:
The foamy waves, which stretched about 50m from Yamba Surf Life Saving Club out to sea didn't deter Tom, 12, and his brother Jack from making the most of the bizarre conditions.
Fishermen planning to drop a line said it was the first time in 30 years they had seen the beach covered in foam.
Like a bathtub full of bubbles, sea foam needs two ingredients," said Dr. Elizabeth L. Venrick, a marine ecologist at the Scripps Institution of Oceanography in La Jolla, Calif., "something to [decrease] the surface tension of the water, like bubble bath, and something to froth it up, like water running into the tub." In the ocean, the "bubble bath" is usually dissolved organic material, she said, and strong surface winds or the breaking of waves on the beach stir up the water with air to make bubbles. "The organic material comes from a number of sources, usually a concentration of biomass, like the phytoplankton bloom that causes red tide or a fish kill," Dr. Venrick said. (A bloom is an increase in the numbers of some species or complex of species that then die or are eaten, releasing organic material.) The material can also come from sewer spills and other terrestrial runoff, she said.The creation of such large amounts of foam is unusual, but not unprecedented. Large amounts of foam also smothered the beach at Pt Cartwright on the Sunshine Coast, Queensland in January 2008. And sea foam also encroached on the shore at Hampton Beach, New Hampshire after stormy weather in April 2007.
Last updated: 23rd August 2008
First published: 23rd August 2008
Write-up by Brett M. Christensen