- 1Leibniz Institute for Tropospheric Research, Modeling of Atmospheric Processes, Leipzig, Germany (roland.schroedner@tropos.de)
- 2Leibniz Institute for Tropospheric Research, Department of Atmospheric Microphysics, Leipzig, Germany
- 3Department of Arctic and Marine Biology, UiT – The Arctic University of Norway, Tromsø, Norway
- 4Leibniz Institute for Tropospheric Research, Atmospheric Chemistry Department, Leipzig, Germany
Ice formation processes influence the radiative properties, precipitation formation and consequently cloud life time in these mixed-phase clouds. Primary ice formation is enabled by so-called ice nucleating particles (INPs). In remote marine regions such as the Southern Ocean, where INP concentrations are naturally low (McCluskey et al., 2018; Tatzelt et al., 2022), discrepancies to atmospheric observations in the representation of cloud phase with strong biases in radiative effects were identified in atmospheric models (Vergara-Temprado et al., 2018). To improve atmospheric models, a better understanding of INP sources, such as sea spray aerosol, INP properties and a physical-sound INP description are needed.
Ice nucleating macromolecules (INMs), that are produced by marine microorganisms, have been described to potentially enter the atmosphere as part of sea spray aerosol (DeMott et al., 2016; Wilson et al., 2015). While INMs produced from terrestrial micro- and more complex organisms could be attributed to e.g. specific proteins and polysaccharides (e.g., Dreischmeier et al., 2017, Frohlich-Nowoisky et al., 2015), we are lacking knowledge about the chemical identity of INMs from the marine biosphere. A polysaccharidic nature of marine INMs is likely as free glucose, a degradation product of polysaccharides and non-ice active monosaccharide, scales with ice activity of Arctic surface seawater (Zeppenfeld et al., 2019).
In this study, we present polysaccharides produced from aquatic eukaryotic microorganisms (incl. thraustochytrid, yeast, filamentous fungus) as relevant ice nucleating macromolecules (INMs) originating from the marine biosphere. In these and samples using polysaccharide standards, it could be shown that normalization by the polysaccharide mass in the sample harmonizes the freezing spectra across different microorganism and standard samples. We parameterized polysaccharidic INMs based on classical nucleation theory and applied this parameterization on global model simulations. A comparison with currently available atmospheric INP observations over the oceans demonstrates a 44% contribution of polysaccharidic INMs to the total marine INPs in the temperature range from -15 °C to -20 °C (Fig. 1). The importance of polysaccharidic INMs is highlighted for remote marine regions.
DeMott, P.J., et al. (2016). Proceedings of the National Academy of Sciences 113, 5797-5803.
Dreischmeier, K., et al. (2017). Scientific Reports 7.
Frohlich-Nowoisky, J., et al. (2015). Biogeosciences 12, 1057-1071.
McCluskey, C.S., et al. (2018). Geophysical Research Letters 45, 11989-11997.
Tatzelt, C., et al. (2022). Atmospheric Chemistry and Physics 22, 9721-9745.
Vergara-Temprado, J., et al. (2018). Proceedings of the National Academy of Sciences 115, 2687-2692.
Wilson, T.W., et al. (2015). Nature 525, 234-+.
Zeppenfeld, S., et al. (2019). Environmental Science & Technology 53, 8747-8756.
How to cite: Schrödner, R., Hartmann, S., Hassett, B., Hartmann, M., van Pinxteren, M., Fomba, K. W., Stratmann, F., Herrmann, H., Pöhlker, M., and Zeppenfeld, S.: Polysaccharides - Important Constituents of Ice Nucleating Particles of Marine Origin, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15357, https://doi.org/10.5194/egusphere-egu25-15357, 2025.
