Art & About’s sea foam shot: what causes this strange phenomenon?

Do these blokes frolicking in a king tide of sea foam at Snapper Rock know what they’re getting into?

TWAM-20150829 EMBARGO FOR TWAM 29 August 2015 NO REUSE WITHOUT PERMISSION Foam at Snapper Rocks Pic : Sarah Murphy

Bubbles do strange things to us. We add them to baths and beer just for the hell of it. We blow them for kids then dance around giddily popping them ourselves.

There are bubbly personalities, and foam parties, and the ineffable joys of bubble-wrap. We get no kicks from flat champagne. And occasionally, the ocean freaks out and delivers up a king tide of bubbles – and what can you do then except jump in and frolic, and try to ignore that quiet but insistent voice in the back of your head that’s saying chemical spill?

Photographer Sandra Murphy watched agog as a layer of spume a metre thick surged ashore at Snapper Rocks in May. First, it buried a couple walking their dog along the path fringing this bay, which was no joke for the mutt – it disappeared for half an hour before finding its way out. Then these three blokes jumped in for a lark. They Came from the Sea, Murphy titled the shot; it’s a finalist in the Australian Life competition – one of 22 photos that’ll be blown up and hung in Sydney’s Hyde Park next month as part of the city’s Art & About festival.

Heart of the nation

So, what caused the foam? A coincidence of two natural events: the mass death of a bloom of phytoplankton, and a big storm. Phytoplankton, the ocean’s primary producers, harness the energy from sunlight to synthesise complex organic compounds such as carbohydrates, fats and proteins. When a bloom dies off, these compounds are released into the ocean, where they act as “surfactants” – that’s to say, they reduce the water’s surface tension… and this, for reasons of mind-boggling physics, makes bubbles more stable and long-lasting. (Soap is an everyday surfactant). So combine that with a storm that produces big, churning seas, and Mother Nature throws a bubble party. Did Murphy jump in too? “Not a chance!” she laughs.