Sunday, May 17, 2009

First detections of biological particles inside ice clouds

Scientific Blogging: A team of atmospheric chemists say they have moved closer to what is considered the "holy grail" of climate change science; the first-ever direct detections of biological particles within ice clouds. The team, led by Kimberly Prather and Kerri Pratt of the University of California at San Diego, Scripps Institution of Oceanography, sampled water droplet and ice crystal residues at high speeds while flying through clouds in the skies over Wyoming.

While it has long been known that microorganisms become airborne and travel great distances, this study is the first to yield direct data on how they work to influence cloud formation. Analysis of the ice crystals revealed that the particles that started their growth were made up almost entirely of either dust or biological material such as bacteria, fungal spores and plant material.

…In climate change science, which derives many of its projections from computer simulations of climate phenomena, the interactions between aerosols and clouds represent what scientists consider the greatest uncertainty in modeling predictions for the future.

"By sampling clouds in real time from an aircraft, these investigators were able to get information about ice particles in clouds at an unprecedented level of detail," said Anne-Marie Schmoltner of NSF's Division of Atmospheric Sciences, which funded the research. "By determining the chemical composition of the very cores of individual ice particles, they discovered that both mineral dust and, surprisingly, biological particles play a major role in the formation of clouds."

…The team demonstrated that both dust and biological material indeed form the nuclei of these ice particles, something that previously could only be simulated in laboratory experiments. "This has really been kind of a holy grail measurement for us," said Prather….

A fast moving cold front approaching, image by NOAA

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