Immersion freezing of ice nucleating active protein complexes

Abstract

Biological particles, e.g. bacteria and their Ice Nucleating Active (INA) protein complexes, might play an important role for the ice formation in atmospheric mixed-phase clouds. Therefore, the immersion freezing behavior of INA protein complexes generated from a Snomax<sup>TM</sup> solution/suspension was investigated as function of temperature in a range of −5 °C to −38 °C at the Leipzig Aerosol Cloud Interaction Simulator (LACIS). The immersion freezing of droplets containing small numbers of INA protein complexes occurs in a temperature range of −7 °C and −10 °C. The experiments performed in the lower temperature range, where all droplets freeze which contain at least one INA protein complex, are used to determine the average number of INA protein complexes present, assuming that the INA protein complexes are Poisson distributed over the droplet ensemble. Knowing the average number of INA protein complexes, the heterogeneous ice nucleation rate and rate coefficient of a single INA protein complex is determined by using the newly-developed CHESS model (stoCHastic model of idEntical poiSSon distributed ice nuclei). Therefore, we assume the ice nucleation process to be of stochastic nature, and a parameterization of the INA protein complex's nucleation rate. Analyzing the results of immersion freezing experiments from literature (Snomax<sup>TM</sup> and <i>Pseudomonas syringae</i> bacteria), to results gained in this study, demonstrates that first, a similar temperature dependence of the heterogeneous ice nucleation rate for a single INA protein complex was found in all experiments, second, the shift of the ice fraction curves to higher temperatures can be explained consistently by a higher average number of INA protein complexes being present in the droplet ensemble, and finally the heterogeneous ice nucleation rate of one single INA protein complex might be also applicable for intact <i>Pseudomonas syringae</i> bacteria cells. The results obtained in this study allow a new perspective on the interpretation of immersion freezing experiments considering INA protein complexes and the derived simple parameterization of the heterogeneous ice nucleation rate can be used in cloud resolving models for studying the effect of bacteria induced ice nucleation

Measurements of Immersion Freezing and Heterogeneous Chemistry of Atmospherically Relevant Single Particles with Micro-Raman Spectroscopy

“…The ice nucleation behavior of a variety of different atmospherically relevant particles including Snomax, kaolinite, montmorillonite, illite NX, lysozyme, lipase, and lipopolysaccharide (LPS) were measured using the environmental cell coupled micro-Raman spectroscopy. Snomax, kaolinite, montmorillonite, and illite NX were chosen as standards; immersion freezing of these systems has been well characterized in the literature across a variety of different immersion ice nucleation systems. − …”

Terrestrial Origin for Abundant Riverine Nanoscale Ice-Nucleating Particles

“…For the derivation of an ice nucleation signature in terms of contact angle distribution, we assume that (i) heterogeneous ice nucleation is an inherently stochastic process 51 and (ii) the distribution of INPs over a droplet population can be described by a Poisson distribution. 50,52 This is realized in a model based on classical nucleation theory 53 in consideration of the average number of INPs. 52 In this framework stochastic and singular ice nucleation behavior and the transition of both can be simulated.…”

Ice nucleation properties of rust and bunt fungal spores and their transport to high altitudes, where they can cause heterogeneous freezing

“…[]; Gonçalves and Massambani [], Hartmann et al . []; Iannone et al . []; Koop and Zobrist []; Möhler et al .…”

“…[4] The importance of biological ice nucleation on cloud dynamics, precipitation, and microphysics, as well as the long-range transport of these particles, has been the focus of some previous modeling studies [Ariya et al, 2009;Diehl and Wurzler, 2010;Diehl et al, 2006;Grützun et al, 2008;Hoose et al, 2010a;Levin et al, 1987;Phillips et al, 2009;Sesartic et al, 2012Sesartic et al, , 2013]. There has also been a renewed interest in laboratory studies on the ice nucleation properties of biological particles, with studies focusing on bacteria, fungal spores, and pollen found in the atmosphere (see, for example, Chernoff and Bertram [2010]; Conen et al [2011]; Despreś et al [2012]; Gonçalves and Massambani [2012], Hartmann et al [2012]; Iannone et al [2011]; Koop and Zobrist [2009]; Möhler et al [2007]; Möhler et al [2008a]; Morris et al [2013]; Pummer et al [2012]; and references therein). Nevertheless, much more work is still needed to quantify the ice nucleation properties of biological particles found in the atmosphere.…”