Prof. Hinrich Grothe, TU Wien, Institute of Materials Chemistry, Vienna, Austria


Ice Nucleating Particles from Birch Forest Ecosystems


Boreal regions exhibit night frosts even during warm seasons and winter temperatures that are as cold as -40°C. Birch trees have adapted to these harsh conditions and make them native to boreal regions. Only recently Felgitsch et al. (2018) have shown that birch leaves, primary wood, secondary wood, bark, and pollen produce ice nucleation active substances which are probably part of the protection mechanism causing extracellular freezing. Pummer et al. (2012, 2015) have shown that these are ice-nucleating macromolecules (INM) in the size of several tens of kilodaltons, which can be washed off from the respective surfaces. Thus one strong precipitation on Scandinavian birch forests can produce up to 170 kg of water suspendable INM. The question is if INM can reach the atmosphere and can contribute to cloud glaciation. Carriers of INM could be fragments of wood, leaf litter, pollen, and mineral dust particles. Here the possibility of sub pollen particles and the stability of INM will be discussed.


Tuesday August 13, 11:15


Rossbysalen C609, Arrhenius laboratory, Svante Arrhenius väg 16C, 6th floor