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M. Bichler, L. Felgitsch, V. Seidl-Seiboth, H. Grothe:
"Ice Nucleation Triggered by Biological Substances";
Poster: EGU General Assembly 2015, Vienna; 04-12-2015 - 04-17-2015; in: "Geophysical Research Abstracts", ol. 17, EGU2015-1805 (2015).

Ice nucleation activity of polysaccharides
Magdalena Bichler (1), Laura Felgitsch (1), Thomas Haeusler (1), Verena Seidl-Seiboth (2), and Hinrich Grothe
(1)
(1) Vienna University of Technology, Institute of Materials Chemistry, Vienna, Austria, (2) Vienna University of Technology,
Institute of Chemical Engineering, Vienna, Austria
Heterogeneous ice nucleation is an important process in the atmosphere. It shows direct impact on our climate by
triggering ice cloud formation and therefore it has much influence on the radiation balance of our planet (Lohmann
et al. 2002; Mishchenko et al. 1996). The process itself is not completely understood so far and many questions
remain open.
Different substances have been found to exhibit ice nucleation activity (INA). Due to their vast differences in
chemistry and morphology it is difficult to predict what substance will make good ice nuclei and which will not.
Hence simple model substances must be found and be tested regarding INA.
Our work aims at gaining to a deeper understanding of heterogeneous ice nucleation. We intend to find some
reference standards with defined chemistry, which may explain the mechanisms of heterogeneous ice nucleation.
A particular focus lies on biological carbohydrates in regards to their INA. Biological carbohydrates are widely
distributed in all kingdoms of life. Mostly they are specific for certain organisms and have well defined purposes,
e.g. structural polysaccharides like chitin (in fungi and insects) and pectin (in plants), which has also water-binding
properties. Since they are widely distributed throughout our biosphere and mostly safe to use for nutrition purposes,
they are well studied and easily accessible, rendering them ideal candidates as proxies.
In our experiments we examined various carbohydrates, like the already mentioned chitin and pectin, as well as
their chemical modifications.
Lohmann U.; A Glaciation Indirect Aerosol Effect Caused by Soot Aerosols; J. Geoph. Res.; Vol. 24 No.4; pp 11-1
- 11-4; 2002
Mishchenko M.I., Rossow W.B., Macke A., Lacis A. A.; Sensitivity of Cirrus Cloud Albedo, Bidirectional Re-
flectance and Optical Thickness Retrieval Accuracy to Ice Particle Shape, J. Geoph. Res.; Vol. 101, No D12; pp.
16,973 - 16,985; 1996

heterogeneous ice nucleation, polysaccharides