UW scientist will try to capture bacteria that freeze clouds
For Gary Franc, the answers to his $234,000 research project may be blowing in the wind--those swirling just aboveground at 10,500-foot Storm Peak Laboratory near Steamboat Springs, Colo.
No stranger to that laboratory--he utilized the lab to complete doctorate research while at Colorado State University in Fort Collins--Franc will use the facility as one site for trying to catch ice nucleating bacteria wafting in the air. He calls them free-floating particulates.
Franc, University of Wyoming Cooperative Extension Service plant pathologist in the College of Agriculture, recently received a $234,416 grant, part of $2 million UW received in federal stimulus funds allocated to the National Science Foundation and the National Institutes of Health meant to energize competitive research projects at universities across the nation.
Franc has been recovering bacteria from winter-time clouds and snow for many years, but the role of bacteria in raindrop or snowflake formation is unknown. The NSF funding will enable Franc and his collaborators to look for a particular kind of bacteria--ice nucleating bacteria--free floating in the atmosphere.
"Ice nucleation-active (INA) bacteria have a peculiar characteristic," said Franc. "Once INA bacteria become established on plant surfaces, the colonized plants will be much more sensitive to temperature and will freeze at a warmer temperature than plants without the bacteria."
INA bacteria on plant surfaces are strains of Pseudomonas syringae, P. viridiflava, P. flourescens, Erwinia herbicola, and Xanthomonas campestris. Franc noted that ice formation is catalyzed by INA bacteria, and frost crystals can expand into internal plant tissues and cause plant injury and also release nutrients, which bacteria utilize as they gain entry to the plant and can cause disease.
Franc's research looks at only a sliver of potential subjects involving INA bacteria. He will peer at the DNA of bacteria captured atop the mountain and other field sites to determine if he has indeed lassoed INA bacteria.
Franc searched for Erwinia carotovora in winter clouds atop 10,531-foot Mount Werner, where the permanent mountain-top lab is located, during research in the early 1980s while at CSU. E. carotovora causes soft rot and blackleg disease in potatoes. Tubers from blackleg-infected plant can develop soft rot, which renders tubers inedible. These same bacteria also infect a wide range of other vegetable crops.
Funding and interest waned in whether bacteria like E. carotovora could be uplifted from ocean bubbles popping in the Pacific Ocean surf and transported cross-continent by storm systems to fall in rain or snow thousands of miles away.
"Now, it's a sexy research area with the interest in climate change and the potential for biogenic ice nucleation involved in the physics of cloud formation," said Franc, a professor in the Department of Plant Sciences. Franc was trained as a bacteriologist, so the research takes him back to his first love.
"It may seem like this (funding) has come out of the blue," he said, "but there has been a long history of laying the foundation."
The research is in collaboration with Paul DeMott and Anthony Prenni, research scientists in the Department of Atmospheric Science at CSU.
"They specialize in measuring ice nuclei from the atmosphere and the physics of cloud formation, and my interest is in bacteria, plants and ecosystems," said Franc. "We hope to weave the two together. We want to determine what percentage of ice nucleating particles are biogenetic in origin, and, if bacterial, what role do they play?"
Franc says his first step is laying infrastructure for the project. He'll identify a stellar Ph.D. student interested in molecular methods for microbial identification or a postdoctoral assistant to help carry the research forward.