Ice nucleation by water-soluble macromolecules
2015
Pummer, B. G. | Budke, C. | Augustin-Bauditz, S. | Niedermeier, D. | Felgitsch, L. | Kampf, C. J. | Huber, R. G. | Liedl, K. R. | Loerting, T. | Moschen, T. | Schauperl, M. | Tollinger, M. | Morris, Cindy E. | Wex, H. | Grothe, H. | Poeschl, U. | Koop, T. | Fröhlich-Nowoisky, Janine | Max Planck Institute for Chemistry (MPIC) ; Max-Planck-Gesellschaft | Universität Bielefeld = Bielefeld University | Leibniz Institute for Tropospheric Research (TROPOS) | Department of Physics ; Michigan Technological University (MTU) | Vienna University of Technology = Technische Universität Wien (TU Wien) | Leopold Franzens Universität Innsbruck - University of Innsbruck | Unité de Pathologie Végétale (PV) ; Institut National de la Recherche Agronomique (INRA) | Max Planck Society; INUIT Research Unit (projects PO1013/5-1, KO2944/2-1, and WE4722/1-1; all for INUIT 1525); Alexander von Humboldt Foundation; Austrian Science Fund (FWF; projects P23027 and P26040); European Science Foundation (MicroDICE)
International audience
اظهر المزيد [+] اقل [-]إنجليزي. Cloud glaciation is critically important for the global radiation budget (albedo) and for initiation of precipitation. But the freezing of pure water droplets requires cooling to temperatures as low as 235 K. Freezing at higher temperatures requires the presence of an ice nucleator, which serves as a template for arranging water molecules in an ice-like manner. It is often assumed that these ice nucleators have to be insoluble particles. We point out that also free macromolecules which are dissolved in water can efficiently induce ice nucleation: the size of such ice nucleating macromolecules (INMs) is in the range of nanometers, corresponding to the size of the critical ice embryo. As the latter is temperature-dependent, we see a correlation between the size of INMs and the ice nucleation temperature as predicted by classical nucleation theory. Different types of INMs have been found in a wide range of biological species and comprise a variety of chemical structures including proteins, saccharides, and lipids. Our investigation of the fungal species<em> Acremonium implicatum</em>, <em>Isaria farinosa</em>, and<em> Mortierella alpina</em> shows that their ice nucleation activity is caused by proteinaceous water-soluble INMs. We combine these new results and literature data on INMs from fungi, bacteria, and pollen with theoretical calculations to develop a chemical in-terpretation of ice nucleation and water-soluble INMs. This has atmospheric implications since many of these INMs can be released by fragmentation of the carrier cell and subsequently may be distributed independently. Up to now, this process has not been accounted for in atmospheric models.
اظهر المزيد [+] اقل [-]المعلومات البيبليوغرافية
تم تزويد هذا السجل من قبل Institut national de la recherche agronomique