- 1TU Wien, Institute of Materials Chemistry, Vienna, Austria (juergen.gratzl@tuwien.ac.at)
- 2Institute of Meteorology and Climate Research, Atmospheric Aerosol Research (IMK-AAF), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
- 3Finnish Meteorological Institute, Atmospheric Composition Research, Helsinki, Finland
- 4Biodiversity Unit, University of Turku, Turku, Finland
- 5Center for Health and Bioresources, AIT Austrian Institute of Technology GmbH, Tulln, Austria
Primary biological aerosol particles (PBAPs), including fungal spores, bacteria and pollen grains, are widely distributed in the atmosphere. Some PBAPs are highly efficient ice nucleating particles (INPs), but their impact on atmospheric ice formation is currently uncertain. PBAPs have been associated with INPs that are active at high sub-zero temperatures and may contribute disproportionally high in places with little anthropogenic influence, such as the high Arctic [1] and in the boreal forest [2].
This study investigates PBAPs and INPs in the pristine Finnish sub-Arctic at the Pallas supersite from September 2022 to September 2023. To study PBAPs, we combine measurements of highly fluorescent aerosol particles (HFAPs) with the Wideband Integrated Bioaerosol Sensor (WIBS) [3], fungal spore counts from a Hirst-type volumetric sampler and eDNA sequence analysis from filter samples. We compare PBAPs to INP measurements over a wide temperature range using the Portable Ice Nucleation Experiment (PINE) [4] and the Ice Nucleation Spectrometer of the Karlsruhe Institute of Technology (INSEKT) [2].
We found a strong seasonal trend of a subset of HFAPs with maximum concentrations in summer and an abrupt and strong decrease with snow cover. Together with an exponential relationship with temperature, this suggests locally emitted bioaerosols. The measured bioaerosols show a positive correlation with INPs active over a wide activation temperature range (-31°C - -8°C). An exceptionally high correlation (r=0.94, p<0.001) was found for INPs active above -13.5°C, showing that WIBS is a powerful tool to predict INP concentrations in biologically dominant environments. Comparison of WIBS data with fungal spore counts indicates the fungal nature of the biological INPs. eDNA analysis revealed a much higher fungal biodiversity than the visually identified spore counts with most of the species belonging to Basidiomycota. Although we found some species known for ice nucleation (e.g. Penicillium_sp, Aspergillus_sp) the ice nucleation of most of the fungi detected has not yet been tested. Future work could contribute to the knowledge of the exact fungal species that dominate the INP population in the sub-Arctic.
This work was supported by ATMO-ACCESS under the ID ATMO-TNA-4-0000000069 and by the FFG under the Project Lab on a Drone (888109).
[1] Pereira Freitas, G. et al. (2023) Nat Commun, 14, 5997
[2] Schneider, J. et al. (2021) Atmos Chem Phys, 21, 3899- 3918
[3] Gratzl, J. et al. (2025), Earth Syst Sci Data (submitted)
[4] Möhler, O. et al. (2021). Atmos Meas Tech. 14(2), 1143-1166.
How to cite: Gratzl, J., Böhmländer, A., Möhler, O., Asmi, E., Pätsi, S., Saarto, A., Pogner, C.-E., Brus, D., Doulgeris, K. M., Stolzenburg, D., Wieland, F., and Grothe, H.: Fluorescent fungal spores as a major contributor to ice nucleating particles in the European sub-Arctic, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5737, https://doi.org/10.5194/egusphere-egu25-5737, 2025.
