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PhD Defense by Lizbeth Dávila Santiago
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In partial fulfillment of the requirements for the degree of
Doctor of Philosophy in Biology
In the
School of Biological Sciences
Lizbeth Dávila Santiago
Will defend her dissertation
TOWARD QUANTIFYING THE PATTERNS OF BACTERIA AND FUNGI IN THE ATMOSPHERE AND THEIR FUNCTIONAL ROLE IN CLOUD FORMATION VIA ICE NUCLEATION
31st MARCH 2023
1:00 PM
https://gatech.zoom.us/j/93028392729
Thesis Advisor:
Konstantinos T. Konstantinidis, Ph.D.
School of Biological Sciences
Georgia Institute of Technology
Committee Members:
Thomas DiCristina, Ph.D.
School of Biological Sciences
Georgia Institute of Technology
Joel Kostka, Ph.D.
School of Biological Sciences
Georgia Institute of Technology
Frank Stewart, Ph.D.
Department of Microbiology and Cell Biology
Montana State University
Nga Lee, Ph.D.
School of Chemical and Biomolecular Engineering
Georgia Institute of Technology
ABSTRACT:
Bioaerosols, specifically airborne bacteria and fungi cells or cell fragments, are ubiquitous in the Earth's atmosphere and could contribute to climate and weather patterns by acting as ice nuclei (IN) for cloud formation and precipitation. However, the composition of airborne microbes and how this may change depending on the prevailing conditions in the atmosphere remain poorly understood despite their apparent importance for public health and the climate. To provide new insights into these questions, we established a time series of dry-air and rain samples, collected in an urban setting (Metro Atlanta) over two consecutive years. Amplicon sequencing of these samples revealed significant changes in microbial composition between dry-air vs. rain, including elevated abundances of pathogenic and/or allergen bacteria and fungi in dry samples, that were not driven by seasonality. Further, we assessed the effect of atmospheric conditions such as high acidic, oxidative and UV radiation stress, on the IN activity of three IN-efficient bacterial species using a newly developed chamber in collaboration in the laboratory. Our results showed that Pseudomonas syringae retained efficient IN activity (T50 above -10ºC; T50 represents the temperature that 50% of the water droplets froze as an effect of the present of the cells) even after viability loss due to acidic pH (pH = 2.5). Collectively, our findings provide new quantitative insights into the public health aspect of bioaerosols as well as their role in weather/climate patterns.
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- Workflow Status:Published
- Created By:Tatianna Richardson
- Created:03/20/2023
- Modified By:Tatianna Richardson
- Modified:03/23/2023
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