AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Single Particle Mass Spectrometry of Biological Particles – Linking Their Chemical Composition to Ice-Nucleation Activity
BERKO SIERAU, Cédric Chou, Monika Kohn, André Welti, Bernhard Pummer, Caroline Oehm, Isabelle Steinke, Olaf Stetzer, Ottmar Möhler, Ulrike Lohmann, ETH Zurich, Institute for Atmospheric & Climate Science
Abstract Number: 89 Working Group: Bioaerosols: Characterization and Environmental Impact
Abstract Atmospheric biological particles such as bacteria, fungal spores and pollen are gaining increasing attention in the research field of cloud microphysics. Their ability to act as heterogeneous ice nuclei has been shown in various laboratory and field studies (e.g. Pratt et al., 2009); however, their atmospheric relevance in aerosol-cloud interactions is still a matter of current research. This is partly due to the lack of understanding of the actual processes driving ice nucleation on biological particles, and the challenging identification of these particles in the field. Both aspects are focus of this study: The ice nucleation behavior of aerosols of diverse biological origin will be presented. Emphasis is put on their identification in the atmosphere using “chemical fingerprints” from single particle mass spectrometric analysis.
We present ice nucleation and single particle mass spectrometry data on the chemical composition of the bacterial cells Pseudomonas syringae and Pseudomonas fluorescence and their residues, fragments of birch and pine pollen, and Lycophyte spores. Additionally, we will discuss results from the analysis of “pollen washing water” containing small fragments of pollen and/or washed-off substances. These substances are expected to play a role in the ice nucleation ability of pollen (Pummer et al., 2012).
The presented data on biological particles helps to explain the ice nucleation process from the chemical point of view, but also provides valuable reference spectra for the mass spectrometric community. For this purpose, we will additionally compare the obtained mass spectrometric “fingerprints” from the bioaerosols with mass spectra of different soil dusts that are potentially bacteria-laden or internally mixed with biological material.
K. A. Pratt et al. (2009) Nature Geosci. 2, 398-401.
B. G. Pummer et al. (2012) Atmos. Chem. Phys., 12, 2541-2555