Contributors and Sponsors LSU students: Amanda Achberger W. Peyton Adkins Meggie Alleman Allen Bordelon Bethany Broekhoven Noelle Bryan Scott Burke Rongman Cai Sahiti Kilaru Other collaborators: Sumeet Dua (LA Tech) Christine Foreman (Montana State) Laurence Henry (Southern University) Cindy Morris (INRA, Montfavet, France) Vaughan Phillips (University of Hawaii) Fred Rainey (Univ. Alaska- Anchorage) David Sands (Montana State) David Schmale (Virginia Tech) Mark Skidmore (Montana State) LSU co-PIs and researchers: John Battista Brad Ellison Jim Giammanco T. Gregory Guzik Doug Granger Gary King Kevin McCarter Michael Stewart John Wefel Cloudy with a chance of microbes Lingering questions about the nature and role of microorganisms in the atmosphere Brent Christner Department of Biological Sciences, Louisiana State University [email protected]
Cloudy with a chance of microbes Lingering questions about the nature and role of microorganisms in the atmosphere Brent Christner Department of Biological Sciences, Louisiana State University [email protected] . Contributors and Sponsors. LSU students: Amanda Achberger W. Peyton Adkins - PowerPoint PPT Presentation
Text of Contributors and Sponsors
Contributors and Sponsors
LSU students: Amanda Achberger W. Peyton Adkins Meggie Alleman Allen Bordelon Bethany Broekhoven Noelle Bryan Scott Burke Rongman Cai Sahiti Kilaru
Other collaborators: Sumeet Dua (LA Tech) Christine Foreman (Montana State) Laurence Henry (Southern University) Cindy Morris (INRA, Montfavet, France) Vaughan Phillips (University of Hawaii) Fred Rainey (Univ. Alaska-Anchorage) David Sands (Montana State) David Schmale (Virginia Tech) Mark Skidmore (Montana State)
LSU co-PIs and researchers: John Battista Brad Ellison Jim Giammanco T. Gregory Guzik Doug Granger Gary King Kevin McCarter Michael Stewart John Wefel
Cloudy with a chance of microbesLingering questions about the nature and role
of microorganisms in the atmosphere
Brent ChristnerDepartment of Biological Sciences, Louisiana State University
Determining the activity, quantity, and nature of freeze immersion ice nuclei or nucleators (IN)
e.g., ‘Untreated’ – ‘Lysozyme’ insensitive = # of bacterial IN
A. Achberger (unpublished data)
Montana France Antarctica and Yukon
IN active at -7oC in freshly collected snow from Montana, France, Antarctica, and the Yukon
~95% of the IN active at > -10oC in snow and rain are biological particles; at least 40% are bacterial in origin
Christner et al. (2008) Science, 319:1214;
Is there a bioprecipitation cycle?
Sands et al. (1982) J Hungarian Meteorol Serv 86:148-152; Morris et al. (2004) J Phys IV France, 121:87-103
Aerosolization of bacterial IN from the phylosphere
Ice nucleation in clouds and enhanced
Epiphytic bacterial growth
Transfer of bacteria to new
In situ detection of biological particlesin cloud ice-crystals
• Sampled ice crystal residues while flying through clouds in the skies over Wyoming, USA.
• Used aircraft-aerosol time-of-flight spectrometry to directly measure the chemistry of individual cloud ice-crystal residues.
• Determined that ~50% of the ice-crystal residues were mineral dust; ~33% were biological particles.
• First evidence for the involvement of biological particles (i.e., bacteria, fungi and/or plant material) in ice-cloud processes.
(Pratt et al. 2009, Nature Geoscience, 2:398-401)
6 x108 km2 total leaf surface for
terrestrial plants(1024 to 1026 cells)
• Do biological IN possess the exclusive role as natural atmospheric IN at temperatures above about -15oC?
• Are their concentrations sufficient to trigger precipitation directly?
• Are unidentified biological particles active IN at lower temperatures?
• Are there large seasonal/regional variations of these types of IN?
• Can their numbers be defined and can they be identified by source?
Demott and Prenni (2010)
Direct measurements of biological IN are lacking for the full temperature regime relevant to ice formation in mixed-phase
Sampling microbes in the lower atmosphere using aerial unmanned autonomous vehicles (UAVs)
Above: A UAV fitted with 8 sampling surfaces that are shown in the open position. Sampling is controlled by remote control from the ground and it is possible to sample > 150,000 L of air during a single flight. Top right: Accurate sampling path (grey lines) of one of the UAVs flying around a single GPS waypoint (black dot) 100 m above the ground.
Images and video: David Schmale (Virginia Tech)
Video: HABITAT-1, July 2009; Image: HABITAT-5, June 2010
Aerobiological sampling using a latex sounding balloon platform
3000 g latex sounding balloon
Cut down apparatus
CW Morse Beacon
Microbiological sampling payloads
A sounding balloon with < 5.4 kg of total payload is a low cost and logistically feasible approach to conduct microbiological sampling at altitudes in the troposphere and stratosphere.
Long duration sampling at 38 km with the High Altitude Student Payload (HASP)
Balloon Manufacturer Winzen
Balloon Type Zero pressure, 1 cap(W11.82-1E-37 CSBF #979)
Balloon Size 11.82 million cubic feet
Parachute Diameter 79 feet
HASP Weight 411 pounds
SIP Weight 589 pounds
Balloon Systems 458 pounds
Ballast 542 pounds
Altitude with Ballast 122,500 feet
Altitude without Ballast 126,000 feet
Ballast for Drive-Up 140 pounds
Ballast for Sunset 259 pounds
Determining the limits for microbial survival in the high atmosphere will…
• yield data to assess the geographic boundaries for microbial dispersal via the atmosphere on a global scale.
• reveal the properties of microbes surviving extremes of low pressure, temperature, and relative humidity and high fluence rates of UV.
• provide information that can be applied to assess the habitability of other planetary environments.
MARSLIFE: Modes of Adaptation, Resistance, and Survival for Life Inhabiting a Freeze-dried-radiation-bathed Environment (2010 NASA / LA BOR grant)
At an altitude of 30 km, the pressure, temperature, and radiation levels are similar to the surface of Mars.
Volume (m3) # of microbes Metric tons of carbonTroposphere (up to 17 km)
4 x 1018 4 to 40 x 1022 400 to 4000 †
Stratosphere (up to 50 km)
8 x 1018 1021 ? 20 ?
† Weight equivalent of 4 to 40 blue whales
“If I could have sampled at 1000 m above the ground with a balloon, the air would have been perfectly sterile.”Louis Pasteur (circa 1860)
Summary• Affect of biological IN on climate? A game of numbers.
• The role of biological IN in precipitation generation could be most relevant in clouds at temperatures > -15oC.
• Collaborative research needed between atmospheric scientists and microbiologists to quantify and characterize the ecological sources and meteorological role of biological IN.
• Species with characteristics (e.g., resistance to desiccation, cold, and UV/ionizing radiation) that provide a selective advantage in the atmosphere are relevant to astrobiology.
• The high altitude limits for life on Earth will provide information to assess the habitability of other planetary environments.