The bacterium Pseudomonas syringae
is so effective at forming ice crystals around itself that it turn cold water into ice almost instantly. This remarkable property is shown in the video below:
The process at work is a form of ice nucleation is the process that forms ice crystals in the atmosphere and, thus, snow. Microbiologist Mark Martin described the process in the video (above).
"In my Microbiology course at the University of Puget Sound, I like to demonstrate the wild and wonderful and weird microbial world. In this video, I supercool a bottle of water to approximately -6 degrees C. I then add a drop of a Pseudomonas syringae culture. This organism makes an ice nucleation protein, which allows the supercooled water to immediately change to water ice...while you watch."
is able to work in its remarkable way
from the proteins that cover its surface membrane. The proteins form a physical structure that water molecules latch onto. This structure also orients the molecules in a way that prompts the formation of ice crystals. The proteins function as the instigator of ice nucleation.
This allows P. syringae
to get water to freeze at higher temperatures than would happen if the bacterium was not present. For example, pure water will not crystallize until temperatures dip down to -40 degrees F.
So, why would a bacterium develop this particular ability? According to Maggie Koerth-Baker at BoingBoing.net
, the current hypothesis is that P. syringae
infects plants, multiplying and growing; however, instead of simply spreading in the air from one plant to another, P. syringae
can sometimes become pushed up into the atmosphere by wind currents. By forming ice crystals, which become rain or snow, the bacteria are able to fall back down to Earth, infecting plants far away from their original hosts.