Environmental & Climate Sciences Department Seminar

"Understanding bioaerosols atmospheric lifecycle, abundance dynamics and impacts"

Presented by Arnaldo Negron Marty, School of Earth and Atmospheric Sciences, Georgia Tech

Thursday, August 15, 2019, 11:00 am — Conference Room Bldg 815E

Primary biological atmospheric particles (PBAP), also called bioaerosols, are ubiquitous in the atmosphere with potentially important impacts on human health1,2, cloud formation3, the hydrological cycle4,5, and biogeochemical cycles6. Measuring PBAP poses a challenge for established biological tools due to generally low atmospheric concentration. Bioaerosols are currently measured by light-induced fluorescence (LIF) instrumentation using the autofluorescence of cell macromolecules, but the frequency of misidentification of abiotic particles by LIF is unclear. As a result, a robust protocol using a state-of-the-art cyclone to collect liquid samples and subsequent flow cytometry analysis, a more specific single-cell detection technique, was effectively designed and applied to quantify the speciated abundance of PBAP7. Tests conducted in Atlanta, GA showed clearly defined low nucleic acid (LNA), high nucleic acid (HNA), and pollen PBAP populations. LNA dominated during dry days and HNA dominated warm and humid days. Our instrumentation pipeline has been deployed during the Biological and Oceanic Atmospheric Study (BOAS) and the Finokalia Aerosol Measurement Experiment (FAME) campaigns. BOAS results show bacteria enrichment at cloud formation altitudes in the marine free troposphere. FAME studied PBAP loadings reaching Crete from continental Europe and Africa air transport; concentrations reached 105 cells m-3 during dust events. Overall, the optimization of detection and quantification techniques has provided tools to study closely speciated bioaerosol populations over different environments and meteorology to better understand bioaerosols lifecycle. References: (1) Fröhlich-Nowoisky et al., Atmos. Res. 2016; (2) Pöschl, Angew. Chem., 2005; (3) Hoose et al., Environ. Res. Lett., 2010; (4) Morris et al., Glob Chang Biol, 2014; (5) DeLeon-Rodriguez et al., PNAS, 2013; (6) Myriokefalitakis et al., Biogeosciences, 2016; (7) Negron-Marty et al., ACP, in

Hosted by: Art Sedlacek and Ernie Lewis

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