Struck by hailstones, MSU grad student peers inside to learn their secrets

A Montana State University graduate student who normally studies microbes in Antarctica is now wondering if some of the hailstones that hammered Gallatin County this summer were formed around live bacteria floating in the atmosphere.

If they were, Alex Michaud could expand his research and eventually contribute to a widely reported MSU discovery that airborne bacteria were involved in the formation of rain and snow over several continents.

In the meantime, Michaud is at the beginning of a study that developed almost as fast as the June 30 hailstorm that caused millions of dollars of damage in shattered windshields, battered houses and dented vehicles all over Bozeman. Hailstones pummeled the roof and siding of Michaud’s house. They cracked the windshield of his 2009 Toyota Corolla while it was parked under a carport.

Michaud is now analyzing eight golfball-size hailstones and hundreds of pea-size hailstones to learn more about their layers and how they formed around a nucleus. He conducts much of his work from inside part of MSU’s Subzero Science and Engineering Research Facility, a frigid laboratory where he wears a winter coat underneath lab overalls. His fingers get so cold that they almost stop working.

When the hailstones hit in June, Michaud gathered some hailstones as curios.

“I thought, ‘What the heck. I’ll pick some up,’” Michaud said. “I have always been taught to look for samples of opportunity.”

Michaud placed the hailstones in a freezer, then spent the rest of the day thinking about the possible relationship between hail and microorganisms. While searching scientific journals for previous findings, he came across a 1973 paper in the journal “Nature” that described microbes found in hailstones. This study simply described the number of culturable bacteria in the different layers of a large hailstone. Michaud thought he might be able to update that study by using modern molecular tools.

“Using DNA, we can identify the bacteria present in the hail to see if they are related to known ice nucleation active bacteria,” Michaud explained. “This is one tool for understanding whether or not bacteria have a role in nucleating hailstones.”

The involvement of live bacteria in rain and snow was a new and surprising discovery for scientists who were used to thinking that rain and snow formed around dust and around many other kinds of airborne particles. Bacteria were not included in meteorological models.

Michaud said scientists have several theories about why bacteria produce large, extra-cellular proteins that cause ice nucleation at temperatures as warm as 28.4 F.

“This may be another piece in the puzzle that helps to answer the many questions surrounding biological ice nucleation,” Michaud said. “Also, most ice nucleation active bacteria are plant pathogens, or at least associated with plant surfaces, so understanding the movement of agriculturally significant organisms will aid farmers in Montana and beyond.”

Michaud also consulted with MSU plant pathologist David Sands and affiliate professor Cindy Morris, who have received considerable publicity for finding active bacteria involved in the formation of rain and snow. They and their co-authors have published their findings in prominent scientific journals such as “Science” and “PNAS” (Proceedings of the National Academy of Science-USA). They’ve just had a paper accepted for publication in “Biogeosciences.” The New York Times featured the discovery earlier this year.

“We kind of thought that hail is this forgotten form of precipitation with respect to ice nucleation active bacteria,” Michaud said.

As the summer progressed, Michaud collected smaller hailstones that fell during subsequent storms in Bozeman and the Hyalite area south of Bozeman. Whenever he heard of hailstones falling in the area, he’d head for his car to retrieve some.

“I had the whole lab on alert,” Michaud said. “I gave everybody sample bags.”

Michaud stores his hailstones in a freezer on the fourth floor of Cobleigh Hall. To examine them, he loads them into a Styrofoam cooler and carries them downstairs to a clean room in the Subzero Science and Engineering Research Facility. Michaud cleans the outside of the hailstones by scraping them with a razor blade. He runs an electric current through a thin wire and pulls the wire through the hailstone to make slices, permitting him to study individual layers.

Michaud will use data from HYSPLIT, an air resources laboratory of the National Oceanic and Atmospheric Administration (NOAA). HYSPLIT data makes it possible to track a storm back to its origins.

Hailstones can form around a variety of substances — not just bacteria, Sands said. HYSPLIT will allow Michaud to see where bacteria or other material might have formed nuclei for hailstones. Sands and Morris, an employee of INRA (the French National Agricultural Research Institute), have been sharing their research techniques with Michaud.

“This is a nice little spin-off, a really good graduate type study,” Sands said of Michaud’s project. “It’s asking one question with a lot of complexity.”

Michaud is a second-year doctoral student officially studying the geomicrobiology of subglacial environments. As a fellow in the National Science Foundation’s IGERT program (Integrative Graduate Education and Research Traineeship), he can initiate side projects, such as the hailstone study, in addition to his Antarctic work with John Priscu, Michaud said. Priscu — internationally known for his Antarctic research — is Michaud’s adviser and a professor in the Department of Land Resources and Environmental Sciences in MSU’s College of Agriculture.

Michaud is involved in several ice-related projects. One deals with bacterial mats in Antarctica.  Another looks at a simulated lake as it freezes from the top down. Michaud traveled to Antarctica during the fall of 2009, and he’ll return there in 2011, 2012 and 2013. Most of his time will be spent on a massive project called WISSARD, or Whillans Ice Stream Subglacial Access Research Drilling. The NSF awarded $10 million to a team of 14 researchers from nine institutions to examine one of Earth’s final frontiers. They will drill through the Whillans Ice Stream and the Ross Ice Shelf and sample rivers and lakes below the Whillans Ice Stream and the grounding zone where the ice stream converges with the ice shelf.