While we cannot see them easily, and obviously find them difficult to
sample, the atmosphere is well endowed with its load of single cell
life. We likely completely underestimate it connectivity besides.
Recall that we have conjectured the existence of methane filled
bubbles made by slime molds able to rise into the stratosphere as
plausible sources of certain types of lights in the sky. We have no
difficulty positing a happy slime mold in a pond of water. How about
all sorts of critters in the pond of oxygen rich atmosphere?
The persistence of a significant bacterial background throughout the
atmosphere actually makes that scenario compelling.
We obviously need to develop technology able to image the deep
atmosphere and to spend way more time in high flying balloons with
special filters over out eyes.
Storm Clouds
Crawling With Bacteria
Tia Ghose
23 January 2013
The storm clouds in
Earth's atmosphere are filled with microbial life, according to a new
study.
The research,
published today (Jan. 23) in the journal PLoS One, revealed
that hailstonesdrawn from storm clouds harbor several species of
bacteria that tend to reside on plants, as well as thousands of
organic compounds normally found in soil. Some of the bacterial
species can seed the tiny ice crystals that lead to rain, suggesting
they play a role in causing rain.
"Those storm
clouds are quite violent phenomena," said study co-author Tina
Santl Temkiv, an environmental chemist at Aarhus University in
Denmark. "They are sucking huge amounts of air from under the
clouds, and that's how the bacteria probably got into the cloud."
Living on a cloud
In the past,
researchers have found bacterial life in clouds that drift over
mountaintops. Bacteria have been found as far up as 24.8 miles (40
kilometers) and may even survive as spores into space, Temkiv
said.
Temkiv and her
colleagues wanted to see if bacteria lived in the violent storm
clouds that hover above the Earth's surface. To find out, they
studied 42 hailstones that had formed in a thunderstorm over
Ljubljana, Slovenia, in May 2009.
After carefully
removing the outer layer and sterilizing the hailstone, they analyzed
its chemical composition.
The team found
thousands of organic, or carbon-containing, compounds — nearly as
many as found in a typical river, Temkiv said. In addition, they
found several species of bacteria that normally live on plants. Some
of the bacteria make a pinkish pigment that allows them to withstand
the punishing ultraviolet rays in the atmosphere.
Some of bacteria
found are ice-nucleators, meaning they can act as seeds for ice
crystals to attach to in the clouds above Earth. When these
same ice crystals get large enough, they fall as rain or snow,
depending on the air temperature.
The findings suggest
that bacteria could influence weather patterns, possibly making rain,
Temkiv said.
"They may be
growing in clouds, increasing in number and then modifying the
chemistry in the cloud but also in the atmosphere indirectly,"
she told LiveScience.
The researchers think
the bacteria come from the air hovering just above Earth that gets
swept into the storm clouds through updrafts. That would suggest the
atmosphere is a thread that can connect distant ecosystems, and
that certain bacteria may be better at colonizing faraway
environments, Pierre Amato, a researcher at France's Blaise Pascal
University who was not involved in the study, wrote in an email.
"Clouds can be
thought of as transient ecosystems selecting for certain [types of
bacteria] that are better fitted than others, and that can thus
quickly disperse over the globe," Amato said. "Understanding
how microbes disperse is relevant, of course, for epidemiology, and
also for microbial ecology."
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