Bright bubbles release bacteria from air to water: study

Boston, November 17:
The bacteria can act as tiny microbial grenades, bursting and propelling microorganisms, including potential pathogens, out of the water and into the air, a study found.
The study, published in the journal Physical Review Letters, revealed that bacteria can affect the longevity of a bubble.
A bubble covered with bacteria floating on the surface of the water can last more than 10 times longer than an uncontaminated bomb, it persists for a few minutes instead of a few seconds, said researchers at the Massachusetts Institute of Technology (MIT) ) in the USA.
Meanwhile, the plug of the contaminated bubble thins.
The thinner the bubble is, the higher the number of droplets that can be projected into the air when the bubble inevitably bursts.
Researchers estimate that a single droplet can hold thousands of microorganisms and each bubble can emit hundreds of droplets.
"We have discovered that bacteria can manipulate the interfaces to improve their own dispersion of water in the air," said Lydia Bourouiba, assistant professor at MIT.
Bourouiba has spent the last few years generating, imaging and meticulously characterizing clean and uncontaminated bubbles, with the aim of establishing a baseline of normal bubble behavior.
"We had to first understand the physics of clean bubbles before we could add organisms like bacteria to see their effect on the system," Bourouiba said.
To directly study the effect of bacteria on bubbles, the team set up an experiment in which it filled a column with a solution of water and different species of bacteria, including E. Coli.
Researchers have developed a system to generate bubbles with an air pump, one at a time, in the column, to control the volume and size of each bubble.
When a bubble came up, the team used high-speed imaging, combined with various optical techniques, to capture its behavior, both at the surface and at its burst.
The researchers observed that once an E. coli-contaminated bubble had reached the surface of the water, its own surface or cork would immediately begin to dilute, mainly by flowing into the water like a melted chocolate shell. (AGENTS)