New Research Sheds Light on Bubble Science

Aug. 22 -- Those soothing sounds of roars and trickles as waves break against the shore have a surprisingly humble origin: Bubbles.

Not only are bubbles behind the dominant sounds above and beneath the sea, they also influence global climate, storm systems and the exchange of gasses and biological matter.

That's why researchers recently spent endless, painstaking hours in the lab counting millions of tiny bubbles in images snapped at the water's surface. By counting bubbles formed in ocean waves and noting their sizes, the team collected information that they believe can lead to a better understanding of the Earth's cycles.

"Understanding the formation of bubbles is key," says Grant Deane, a physicist at Scripps Institution of Oceanography at the University of California at San Diego who authored a study about bubbles with Scripps colleague M. Dale Stokes in this week's issue of Nature. "It's an important part of the puzzle to understanding global warming and underwater noise."

Bubble Magic

Bubbles influence the environment mostly as they form and break. As ocean waves crest and topple, air and sea water mix to form whitecaps. Inside each whitecap is a rich swirl of bubbles called the bubble plume.

As these bubbles form, they pocket gasses and transfer them between the air and sea. As they rise up through the water column, they scrub out and collect organic material and bacteria. Finally, at the surface, bubbles burst and release tiny droplets — and their contents — into the atmosphere.

These droplets contribute to clouds and weather systems and transfer matter and gasses long distances (one reason why cars rust more quickly in coastal towns is due to airborne salt released by bubbles). The same salty sea spray also cleanses pollution from the air as they form raindrops, which drag particles of pollution down into the water, a recent study found.

Sidney Perkowitz, a professor of physics at Emory University and author of the book, Universal Foam, adds that bubbles can even release tiny living things or pieces of living things when they burst above the water's surface.