10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
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Molecular Genetic Staining Techniques for Bioaerosol Analysis in the Amazon Rainforest
MARIA PRASS, Florian Ditas, Isabella Hrabe de Angelis, Bruna A. Holanda, Oliver Lauer, Ovid Krüger, Bettina Weber, Paulo Artaxo, Eckhard Thines, Bernhard M. Fuchs, Meinrat O. Andreae, Ulrich Pöschl, Christopher Pöhlker, Max Planck Institute for Chemistry, Mainz, Germany
Abstract Number: 1196 Working Group: Bioaerosols
Abstract Bioaerosols, such as pollen, bacterial and fungal spores or plant fragments, can be seen as natural markers for the interaction between biosphere and atmosphere. Besides their ecological function as dispersal units of biological organisms they also influence physical and chemical processes in the atmosphere. They play an important role in cloud microphysics by acting as giant cloud condensation nuclei and ice nuclei. An extensive set of bioaerosol detection techniques is existing, however, the analysis is challenging due to their high complexity in terms of size, morphology and cell physiology. The current scientific knowledge about bioaerosols suffers from a lack of methods to individually identify and quantify these highly diverse particles in environmental samples. Here, we present a study using a molecular genetic staining method to investigate bioaerosol composition, concentration and morphological properties in the tropical rainforest in the Amazon basin. Filter samples from three different heights (5, 60, and 325 m) at the Amazon Tall Tower Observatory (ATTO) were analyzed using Fluorescence In Situ Hybridization (FISH). FISH is based on the annealing of a specific, fluorescently labeled oligonucleotide probe to the target cell’s ribonucleic acid. This way, single cells can be detected in the microbial community on filter samples via fluorescence microscopy. This is the first study based on direct visualization of bioaerosol’s taxonomic diversity in a pristine rainforest.
Initial results show pronounced gradients in the rain forest boundary layer with substantially higher bioaerosol mass abundance below the forest canopy. It clearly stands out that small bioaerosol particle (1-2 µm) are more efficiently transported to higher altitudes, whereas larger eukaryotic cells (mostly fungal spores) show high abundances in the canopy space. Our results presented here are a first step towards a quantification of taxonomically resolved bioaerosol fluxes from the forest ecosystem to altitudes (i.e., cloud base height), where they become relevant for cloud microphysics.