Yamba the cappuccino coast
WHILE most people would love to sit at Yamba’s iconic Pacific Hotel sipping on a coffee, they wouldn’t want the foam covering Main Beach yesterday topping their cappuccino.
Huge swells over the past week have seen beaches in northern NSW and southern Queensland turned into the ‘cappuccino coast’, with the tan tinged natural phenomenon between one and two metres deep on many Clarence Valley beaches.
The foam often attracts the attention of curious individuals wanting to frolic in the fluffy froth.
But associate professor Steve Smith, of Southern Cross University’s National Marine Science Centre, said playing in the foam posed a risk for people primarily due to the potential of sustaining physical injury and not illness.
“There might be items concealed in the foam like branches or debris washed up on the beach or even rocks and people running or playing in the foam can damage themselves that way,” he said.
He said the risk of contracting any types of infection from the foam was low unless there was an occurrence of nearby pollution.
“I would imagine there is no greater risk from playing in the foam than in the ocean, unless you have got that accumulated toxicity there and that would be very much site dependent,” he said.
Prof Smith said the foam was created by large waves plunging air bubbles into seawater.
He said the foam can remain for several days due to the natural reaction of marine organisms enduring turbulence releasing “thickening agents”, which coat the foam and delay the normal process of the bubbles breaking down.
“These thickening agents, or alginates, are very well recognised and used throughout industry due to their special properties,” he said.
He said he was not aware of any research evidence that this process was a defence mechanism or evolutionary process of marine organisms, including seaweed, that naturally contain these alginates in tissues that make up their structure.
“If you look at it under the microscope you can see the foam is composed of little bits of seaweed and bits of small sea organisms trapped in the foam,” he said.
He said a common example of the use of cultured or deliberately grown alginates was in the manufacture of ice cream to give body or help it bind.
Commercial varieties of alginate are commonly extracted from seaweed. According to a report prepared by Queensland’s Griffith University Centre for Coastal Management, several factors contribute to the accumulation of masses of foam on beaches. These include the exposure of a stretch of beach to wind; how heavy the rain is, and; the shape and direction of the swell producing the foam.
The report states the occurrence of foam is also more prevalent on beaches subject to erosion or those where waves abruptly reach a cliff.
The foam was beginning to recede yesterday afternoon, but could be back later in the week with more rain and heavy swell predicted.