American Society for Microbiology
The role of bacteria in weather events
NEW ORLEANS, LA – May 24, 2011 — Researchers have discovered a high concentration of bacteria in the center of hailstones, suggesting that airborne microorganisms may be responsible for that and other weather events. They report their findings today at the 111th General Meeting of the American Society for Microbiology in New Orleans.
“Bacteria have been found within the embryo, the first part of a hailstone to develop. The embryo is a snapshot of what was involved with the event that initiated growth of the hailstone,” says Alexander Michaud of Montana State University in Bozeman, who presented the research.
Michaud and his colleagues analyzed hailstones over 5 centimeters in diameter that were collected on the University campus after a storm in June 2010. The large hailstones were seperated into 4 layers and the meltwater from each layer was analyzed. The number of culturable bacteria was found to be highest in the inner cores of the hailstone.
“In order for precipitation to occur, a nucleating particle must be present to allow for aggregation of water molecules,” says Michaud. “There is growing evidence that these nuclei can be bacteria or other biological particles.”
Michaud’s research is part of a growing field of study focusing on bioprecipitation, a concept where bacteria may initiate rainfall and other forms of precipitation including snow and hail. The formation of ice in clouds, which is necessary for snow and most rainfall events, requires ice nuclei (IN), particles that the ice crystals can grow around.
“Aerosols in clouds play key roles in the processes leading to precipitation due to their ability to serve as sites for ice nucleation. At temperatures warmer than -40 degrees Celsius ice formation is not spontaneous and requires an IN,” says Brent Christner of Louisiana State University, also presenting at the meeting.
A diverse range of particles are capable of serving as IN, but the most active naturally occurring IN are biological in origin, capable of catalyzing ice formations at temperatures near -2 degrees Celsius. The most well-studied biological IN is the plant pathogen Psuedomonas syringae.
“Ice nucleating strains of P. syringae possess a gene that encodes a protein in their outer membrane that binds water molecules in an ordered arrangement, providing a very efficient nucleating template that enhances ice crystal formation,” says Christner.
Aerosol-cloud simulation models imply that high concentrations of biological IN may influence the average concentration and size of ice crystals in clouds, horizontal cloud coverage in the free troposphere, precipitation levels at the ground and even insulation of the earth from solar radiation.
“Evidence for the distribution of biological IN in the atmosphere coupled with the warm temperatures at which they function as IN has implied that biological IN may play a role in the Earth’s hydrological cycle and radiative balance,” says Christner.
Garry
It happened a few years back to a British hang-glider pilot over in Spain somewhere, came up in some flight-safety article. He was spat out at top – fortunately he was in a warm, sleeping-bag-like sling (which formed an ice layer) and had a parachute, as he was spat out unconscious from near the top of the storm, and woke up just in time to open his ‘chute.
Laurie Bowen is clearly unaware of the rain scrubbing problem.
Disclaimer: I am one of THOSE people. I was there. I’ve heard the talk.
Of course bacteria cause nucleation and rain and hail and modulate albedo and hitch rides in the stratosphere ’round and ’round the planet. And eat people and asphalt.
Bacteria Rule! FILO = First In, Last Out.
I am grateful to Jimbo for his links.
The second one, http://www.oewf.org/tripolar/wordpress/wp-content/uploads/2011/02/19_Sattler_et_al_2001.pdf shows that I was wrong.
“… the number of bacteria in cloud water approx 1500 per ml is far lower than the number of cloud droplets forming one ml approx 200,000,000 it appears that bacteria, – although growing in cloud droplets, – are not an important source of cloud condensation nuclei”
I’ve amended some symbols etc. for ease of typing, but I believe I quote it fairly.
Cynical Bastard who says: May 25, 2011 at 2:44 pm “Laurie Bowen is clearly unaware of the rain scrubbing problem.”
You are absolutely correct . . . I haven’t a clue what this means . . . . If you are talking about the acid rains that results from volcanoes and the like . . . or the scrubbers that have been mandated for power plants. . . .
Please, enlighten me on the importance (who, when, where, what, how, and why’s) of your statement . .
“scrubbers to remove sulfur compounds from their flue gases”
http://www.sciencedaily.com/releases/2010/10/101021104735.htm
Laura Bowen – with pleasure.
Imagine you have a GI tract problem. Imagine your doctor orders a stool sample for microbiological analysis. Would you collect that sample, ahem, at the source, or from the sewer 5 miles downstream?
…same general idea. By the time rain hits the ground, it has fallen through whatever thickness of the atmosphere, harvesting all sorts of particles. Can you tell which are which? I can’t, and neither is anybody else (so I am exaggerating for the sake of illustration, but that’s the idea). And if the rain doesn’t fall, the only way to find out what’s up there, is to GO up there.
Incidentally, the guy’s planes are nothing more than large models, with samplers and guidance systems. A lot cheaper than sending a whole bloody C-130 up.
@Cynical Bastard Thank-you I did not understand the terminology you were using or what you were even referring to . . . and I was not aware that they were already using “models, with samplers and guidance systems” . . . . glad to hear it . . . it is a whole lot cheaper . . . and safer.
Finally, as for your analogy . . .