The Impact of (bio-)organic substances on the ice nucleation activity of the K-feldspar microcline in aqueous solutions

Abstract. Potassium-feldspars (K-feldspars), such as microcline, are considered key dust minerals inciting ice nucleation in mixed phase clouds. Besides the high ice nucleation activity of microcline, recent studies also revealed a high sensi-tivity of microcline towards interaction with solutes on its surface. Here, we investigate the effect of organic and bio-organic substances on the ice nucleation activity of microcline, with the aim to better understand the underlying sur-face interactions. We performed immersion freezing experiments with microcline in solutions of three carboxylic acids, five amino acids and two polyols to represent these compound classes. By means of a differential scanning calorimeter we investigated the freezing of emulsified droplets of microcline suspended in various solutions. Depend-ing on the type of solute, different effects were observed. In the case of carboxylic acids (acetic, oxalic and citric acid), the measured heterogeneous onset temperatures, Thet, showed no significant deviation from the behavior pre-dicted by the water activity criterion, Thet(aw) = Tmelt(aw+Δaw), which relates Thet with the melting point temperature Tmelt via a constant water activity offset Δaw. While this behavior could be interpreted as a lack of interaction of the solute molecules with the surface, the carboxylic acids caused the fraction of heterogeneously frozen water, Fhet(aw), to decrease by up to 40 % with increasing solute concentrations. In combination, unaltered Thet(aw) and reduced Fhet(aw) suggest that active sites were largely deactivated by the acid molecules, but amongst those remaining active are also the best sites with the highest Thet. A deviation from this behavior is citric acid, which showed not only a de-crease in Fhet, but also a decrease in Thet of up to 4 K for water activities below 0.99, pointing to a depletion of the best active sites by interactions with the citrate ions. When neutralized solutions of the acids were used instead, the de-crease in Fhet became even more pronounced. The slope of Thet(aw) was different for each of the neutralized acid solu-tions. In the case of amino acid solutions, we found a decrease in Thet (up to 10 K), significantly below the Δaw-criterion, as well as a reduction in Fhet (up to 60 %). Finally, in case of the investigated polyols, no significant devia-tion of Thet from the Δaw-criterion was observed, and no significant deviation of Fhet in comparison to a pure water suspension was found. Furthermore, we measured the effects of aging on the ice nucleation activity in experiments with microcline suspended in solutions for up to seven days, and tested the reversibility of the interaction with the solutes after aging for 10 days. For citric acid, an ongoing irreversible degradation of the ice nucleation activity was observed, whereas the amino acids showed completely reversible effects. In summary, our experiments demonstrate a remarkable sensitivity of microcline ice nucleation activity to surface interactions with various solutes, underscoring the importance of the history of such particles from source to frozen cloud droplet in the atmosphere.

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Supplementary material to "The Impact of (bio-)organic substances on the ice nucleation activity of the K-feldspar microcline in aqueous solutions"

10.5194/acp-2021-806-supplement ◽

2021 ◽

Author(s):

Kristian Klumpp ◽

Claudia Marcolli ◽

Thomas Peter

Keyword(s):

Aqueous Solutions ◽

Ice Nucleation ◽

Organic Substances ◽

Supplementary Material ◽

Nucleation Activity ◽

Ice Nucleation Activity ◽

The Impact

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Suspendable macromolecules are responsible for ice nucleation activity of birch and conifer pollen

Atmospheric Chemistry and Physics ◽

10.5194/acp-12-2541-2012 ◽

2012 ◽

Vol 12 (5) ◽

pp. 2541-2550 ◽

Cited By ~ 150

Author(s):

B. G. Pummer ◽

H. Bauer ◽

J. Bernardi ◽

S. Bleicher ◽

H. Grothe

Keyword(s):

Radiative Forcing ◽

Pollen Grains ◽

Ice Nucleation ◽

Cloud Formation ◽

Distribution Area ◽

Ice Cloud ◽

Ice Nuclei ◽

Nucleation Activity ◽

Ice Nucleation Activity ◽

The Impact

Abstract. The ice nucleation of bioaerosols (bacteria, pollen, spores, etc.) is a topic of growing interest, since their impact on ice cloud formation and thus on radiative forcing, an important parameter in global climate, is not yet fully understood. Here we show that pollen of different species strongly differ in their ice nucleation behaviour. The average freezing temperatures in laboratory experiments range from 240 to 255 K. As the most efficient nuclei (silver birch, Scots pine and common juniper pollen) have a distribution area up to the Northern timberline, their ice nucleation activity might be a cryoprotective mechanism. Far more intriguingly, it has turned out that water, which has been in contact with pollen and then been separated from the bodies, nucleates as good as the pollen grains themselves. The ice nuclei have to be easily-suspendable macromolecules located on the pollen. Once extracted, they can be distributed further through the atmosphere than the heavy pollen grains and so presumably augment the impact of pollen on ice cloud formation even in the upper troposphere. Our experiments lead to the conclusion that pollen ice nuclei, in contrast to bacterial and fungal ice nucleating proteins, are non-proteinaceous compounds.

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Complex plant-derived organic aerosol as ice-nucleating particles – more than the sums of their parts?

Atmospheric Chemistry and Physics ◽

10.5194/acp-20-11387-2020 ◽

2020 ◽

Vol 20 (19) ◽

pp. 11387-11397

Author(s):

Isabelle Steinke ◽

Naruki Hiranuma ◽

Roger Funk ◽

Kristina Höhler ◽

Nadine Tüllmann ◽

...

Keyword(s):

Organic Aerosol ◽

Ice Nucleation ◽

Individual Plant ◽

Vast Number ◽

Nucleation Activity ◽

Organic Particles ◽

Ice Nucleation Activity ◽

The Impact ◽

Complex Organic ◽

Plant Components

Abstract. Quantifying the impact of complex organic particles on the formation of ice crystals in clouds remains challenging, mostly due to the vast number of different sources ranging from sea spray to agricultural areas. In particular, there are many open questions regarding the ice nucleation properties of organic particles released from terrestrial sources such as decaying plant material. In this work, we present results from laboratory studies investigating the immersion freezing properties of individual organic compounds commonly found in plant tissue and complex organic aerosol particles from vegetated environments, without specifically investigating the contribution from biological particles, which may contribute to the overall ice nucleation efficiency observed at high temperatures. To characterize the ice nucleation properties of plant-related aerosol samples for temperatures between 242 and 267 K, we used the Aerosol Interaction and Dynamics in the Atmosphere (AIDA) cloud chamber and the Ice Nucleation SpEctrometer of the Karlsruhe Institute of Technology (INSEKT), which is a droplet freezing assay. Individual plant components (polysaccharides, lignin, soy and rice protein) were mostly less ice active, or similarly ice active, compared to microcrystalline cellulose, which has been suggested by recent studies to be a proxy for quantifying the primary cloud ice formation caused by particles originating from vegetation. In contrast, samples from ambient sources with a complex organic matter composition (agricultural soils and leaf litter) were either similarly ice active or up to 2 orders of magnitude more ice active than cellulose. Of all individual organic plant components, only carnauba wax (i.e., lipids) showed a similarly high ice nucleation activity as that of the samples from vegetated environments over a temperature range between 245 and 252 K. Hence, based on our experimental results, we suggest considering cellulose as being representative for the average ice nucleation activity of plant-derived particles, whereas lignin and plant proteins tend to provide a lower limit. In contrast, complex biogenic particles may exhibit ice nucleation activities which are up to 2 orders of magnitude higher than observed for cellulose, making ambient plant-derived particles a potentially important contributor to the population of ice-nucleating particles in the troposphere, even though major uncertainties regarding their transport to cloud altitude remain.

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Macromolecular fungal ice nuclei in <i>Fusarium</i>: effects of physical and chemical processing

Biogeosciences ◽

10.5194/bg-16-4647-2019 ◽

2019 ◽

Vol 16 (23) ◽

pp. 4647-4659 ◽

Cited By ~ 3

Author(s):

Anna T. Kunert ◽

Mira L. Pöhlker ◽

Kai Tang ◽

Carola S. Krevert ◽

Carsten Wieder ◽

...

Keyword(s):

Fusarium Species ◽

Ice Nucleation ◽

Cumulative Number ◽

Genus Fusarium ◽

Biological Particles ◽

Ice Nuclei ◽

Nucleation Activity ◽

Ice Nucleation Activity ◽

The Impact ◽

Atmospherically Relevant

Abstract. Some biological particles and macromolecules are particularly efficient ice nuclei (IN), triggering ice formation at temperatures close to 0 ∘C. The impact of biological particles on cloud glaciation and the formation of precipitation is still poorly understood and constitutes a large gap in the scientific understanding of the interactions and coevolution of life and climate. Ice nucleation activity in fungi was first discovered in the cosmopolitan genus Fusarium, which is widespread in soil and plants, has been found in atmospheric aerosol and cloud water samples, and can be regarded as the best studied ice-nucleation-active (IN-active) fungus. The frequency and distribution of ice nucleation activity within Fusarium, however, remains elusive. Here, we tested more than 100 strains from 65 different Fusarium species for ice nucleation activity. In total, ∼11 % of all tested species included IN-active strains, and ∼16 % of all tested strains showed ice nucleation activity above −12 ∘C. Besides Fusarium species with known ice nucleation activity, F. armeniacum, F. begoniae, F. concentricum, and F. langsethiae were newly identified as IN-active. The cumulative number of IN per gram of mycelium for all tested Fusarium species was comparable to other biological IN like Sarocladium implicatum, Mortierella alpina, and Snomax®. Filtration experiments indicate that cell-free ice-nucleating macromolecules (INMs) from Fusarium are smaller than 100 kDa and that molecular aggregates can be formed in solution. Long-term storage and freeze–thaw cycle experiments revealed that the fungal IN in aqueous solution remain active over several months and in the course of repeated freezing and thawing. Exposure to ozone and nitrogen dioxide at atmospherically relevant concentration levels also did not affect the ice nucleation activity. Heat treatments at 40 to 98 ∘C, however, strongly reduced the observed IN concentrations, confirming earlier hypotheses that the INM in Fusarium largely consists of a proteinaceous compound. The frequency and the wide distribution of ice nucleation activity within the genus Fusarium, combined with the stability of the IN under atmospherically relevant conditions, suggest a larger implication of fungal IN on Earth’s water cycle and climate than previously assumed.

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A laboratory investigation of the ice nucleation efficiency of three types of mineral and soil dust

10.5194/acp-2018-543 ◽

2018 ◽

Author(s):

Mikhail Paramonov ◽

Robert O. David ◽

Ruben Kretzschmar ◽

Zamin A. Kanji

Keyword(s):

Active Sites ◽

Particle Surface ◽

Ice Nucleation ◽

Dust Particles ◽

Bet Surface Area ◽

Soil Dust ◽

Organic Components ◽

Nucleation Activity ◽

Ice Nucleation Activity ◽

Soluble Material

Abstract. Surface-collected dust from three different locations around the world was examined with respect to its ice nucleation activity (INA) with the Portable Ice Nucleation Chamber (PINC). Ice nucleation experiments were conducted with particles of 200 and 400 nm in diameter in the temperature range of 233–243 K in both deposition nucleation and condensation freezing regimes. Several treatments were performed in order to investigate the effect of mineralogical composition, as well as the presence of biological and proteinaceous, organic and soluble compounds on the INA of mineral and soil dust. The INA of untreated dust particles correlated well with the total feldspar and K-feldspar content, corroborating previously published results. The removal of heat-sensitive proteinaceous and organic components from the particle surface with heat decreased the INA of dusts. However, the decrease in the INA was not proportional to the amount of these organic components, indicating that different proteinaceous and organic species have different ice nucleation activities, and the exact speciation is required in order to determine why dusts respond differently to the heating process. The INA of certain dusts increased after the removal of soluble material from the particle surface, demonstrating the low INA of the soluble compounds and/or the exposition of the underlying active sites. Similar to the proteinaceous organic compounds, soluble compounds seem to have different effects on the INA of surface-collected dusts, and a general conclusion about how the presence of soluble material on the particle surface affects its INA is not possible. The investigation of the heated and washed dusts revealed that mineralogy alone is not able to fully explain the observed INA of surface-collected dusts at the examined temperature and relative humidity conditions. The results showed that it is not possible to predict the INA of surface-collected soil dust based on the presence and amount of certain minerals or any particular class of compounds, such as soluble or proteinaceous/organic. Instead, at temperatures of 238–243 K the ice nucleation activity of the untreated, surface-collected soil dust in condensation freezing mode can be roughly approximated by one of the existing surrogates for atmospheric mineral dust, such as illite NX. Uncertainties associated with mechanical damage and possible changes to the mineralogy during treatments, as well as with the BET surface area and its immediate impact on the number of active sites ns,BET parameterisation, are addressed.

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Ice nucleation efficiency of natural dust samples in the immersion mode

Atmospheric Chemistry and Physics ◽

10.5194/acp-16-11177-2016 ◽

2016 ◽

Vol 16 (17) ◽

pp. 11177-11206 ◽

Cited By ~ 30

Author(s):

Lukas Kaufmann ◽

Claudia Marcolli ◽

Julian Hofer ◽

Valeria Pinti ◽

Christopher R. Hoyle ◽

...

Keyword(s):

Clay Minerals ◽

Active Sites ◽

Aqueous Suspension ◽

Mineralogical Composition ◽

Dust Sample ◽

Ice Nucleation ◽

Scanning Calorimetry ◽

Dust Collection ◽

Nucleation Activity ◽

Ice Nucleation Activity

Abstract. A total of 12 natural surface dust samples, which were surface-collected on four continents, most of them in dust source regions, were investigated with respect to their ice nucleation activity. Dust collection sites were distributed across Africa, South America, the Middle East, and Antarctica. Mineralogical composition has been determined by means of X-ray diffraction. All samples proved to be mixtures of minerals, with major contributions from quartz, calcite, clay minerals, K-feldspars, and (Na, Ca)-feldspars. Reference samples of these minerals were investigated with the same methods as the natural dust samples. Furthermore, Arizona test dust (ATD) was re-evaluated as a benchmark. Immersion freezing of emulsion and bulk samples was investigated by differential scanning calorimetry. For emulsion measurements, water droplets with a size distribution peaking at about 2 µm, containing different amounts of dust between 0.5 and 50 wt % were cooled until all droplets were frozen. These measurements characterize the average freezing behaviour of particles, as they are sensitive to the average active sites present in a dust sample. In addition, bulk measurements were conducted with one single 2 mg droplet consisting of a 5 wt % aqueous suspension of the dusts/minerals. These measurements allow the investigation of the best ice-nucleating particles/sites available in a dust sample. All natural dusts, except for the Antarctica and ATD samples, froze in a remarkably narrow temperature range with the heterogeneously frozen fraction reaching 10 % between 244 and 250 K, 25 % between 242 and 246 K, and 50 % between 239 and 244 K. Bulk freezing occurred between 255 and 265 K. In contrast to the natural dusts, the reference minerals revealed ice nucleation temperatures with 2–3 times larger scatter. Calcite, dolomite, dolostone, and muscovite can be considered ice nucleation inactive. For microcline samples, a 50 % heterogeneously frozen fraction occurred above 245 K for all tested suspension concentrations, and a microcline mineral showed bulk freezing temperatures even above 270 K. This makes microcline (KAlSi3O8) an exceptionally good ice-nucleating mineral, superior to all other analysed K-feldspars, (Na, Ca)-feldspars, and the clay minerals. In summary, the mineralogical composition can explain the observed freezing behaviour of 5 of the investigated 12 natural dust samples, and partly for 6 samples, leaving the freezing efficiency of only 1 sample not easily explained in terms of its mineral reference components. While this suggests that mineralogical composition is a major determinant of ice-nucleating ability, in practice, most natural samples consist of a mixture of minerals, and this mixture seems to lead to remarkably similar ice nucleation abilities, regardless of their exact composition, so that global models, in a first approximation, may represent mineral dust as a single species with respect to ice nucleation activity. However, more sophisticated representations of ice nucleation by mineral dusts should rely on the mineralogical composition based on a source scheme of dust emissions.

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Complex plant-derived organic aerosol as ice-nucleating particles – more than a sum of their parts?

10.5194/acp-2019-869 ◽

2019 ◽

Author(s):

Isabelle Steinke ◽

Naruki Hiranuma ◽

Roger Funk ◽

Kristina Höhler ◽

Nadine Tüllmann ◽

...

Keyword(s):

Organic Aerosol ◽

Ice Nucleation ◽

Individual Plant ◽

Vast Number ◽

Nucleation Activity ◽

Organic Particles ◽

Ice Nucleation Activity ◽

The Impact ◽

Complex Organic ◽

Plant Components

Abstract. Quantifying the impact of complex organic particles on the formation of ice crystals in clouds remains challenging, mostly due to the vast number of different sources ranging from sea spray to agricultural areas. In particular, there are many open questions regarding the ice nucleation properties of organic particles released from terrestrial sources such as decaying plant material. In this work, we present results from laboratory studies investigating the immersion freezing properties of individual organic compounds commonly found in plant tissue and complex organic aerosol particles from vegetated environments. To characterize the ice nucleation properties of plant-related aerosol samples for temperatures between 242 and 267 K, we used the Aerosol Interaction and Dynamics in the Atmosphere (AIDA) cloud chamber and the Ice Nucleation Spectrometer of the Karlsruhe Institute of Technology (INSEKT), which is a droplet freezing assay. Individual plant components (polysaccharides, lignin, soy and rice protein) were mostly less or similarly ice-active compared to microcrystalline cellulose, which has been suggested by recent studies as a proxy for quantifying the primary cloud ice formation caused by particles originating from vegetation. In contrast, samples from ambient sources with a complex organic matter composition (agricultural soils, leaf litter) were either similarly ice-active or up to two orders of magnitude more ice-active than cellulose. Of all individual organic plant components, only carnauba wax (i.e. lipids) showed a similarly high ice nucleation activity as the samples from vegetated environments over a temperature range between 245 and 252 K. Hence, based on our experimental results, we suggest to consider cellulose as being representative for the average ice nucleation activity of plant-derived particles, whereas lignin and plant proteins tend to provide a lower limit. In contrast, complex biological particles may exhibit ice nucleation activities which are up to two orders of magnitude higher than observed for cellulose, making ambient plant-derived particles a potentially important contributor to the population of ice-nucleating particles in the troposphere.

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Survival and ice nucleation activity ofPseudomonas syringaestrains exposed to simulated high-altitude atmospheric conditions

10.1101/408906 ◽

2018 ◽

Author(s):

Gabriel Guarany de Araujo ◽

Fabio Rodrigues ◽

Fabio Luiz Teixeira Gonçalves ◽

Douglas Galante

Keyword(s):

Pseudomonas Syringae ◽

Water Samples ◽

Cloud Water ◽

Ice Nucleation ◽

Important Process ◽

High Altitudes ◽

Ice Nuclei ◽

Nucleation Activity ◽

Ice Nucleation Activity ◽

The Impact

ABSTRACTThe epiphytic bacteriumPseudomonas syringaeproduces the most efficient and well-studied biological ice nuclei (IN) known. Bioaerosols containing these cells have been proposed to influence cloud glaciation, an important process in the initiation of precipitation. The presence of this species has been reported on rain, snow, and cloud water samples, but how these organisms can survive the harsh conditions present on the high atmosphere still remains to be better understood. In this study, the impact caused by this type of environment onP. syringaewas assayed by measuring their viability and IN activity. Two strains, of the pathovarssyringaeandgarcae, were compared toEscherichia coli.While UV-C radiation effectively inactivated these cells, thePseudomonaswere much more tolerant to UV-B. TheP. syringaestrains were also more resistant to “environmental” UV radiation from a solar simulator, composed of UV-A and UV-B. The response of their IN after long exposures to this radiation varied: only one strain suffered a relatively small 10-fold reduction in IN activity at -5 °C. Desiccation at different relative humidity values also affected the IN, but some activity at -5 °C was still maintained for all tests. The pathovargarcaetended to be more resistant to the stress treatments than the pathovarsyringae, particularly to desiccation, though its IN were found to be more sensitive. Compared toE. coli, theP. syringaestrains seemed relatively better adapted to survival under conditions present on the atmosphere at high altitudes.IMPORTANCEThe plant-associated bacteriumPseudomonas syringaeproduces on its outer membrane highly efficient ice nuclei which are able to induce the freezing of supercooled water. This ability has been linked to increased frost damaged on colonized leaves and also to the formation of ice in clouds, an important process leading to precipitation.P. syringaehas been found on rain, snow, and cloud water samples, confirming its presence on the atmosphere. This study aimed to assess the survival of these cells and the maintenance of their ice nucleation activity under stressing conditions present in high altitudes: ultraviolet radiation and desiccation.P. syringaestrains were shown to at least partially tolerate these factors, and their most efficient ice nuclei, while affected, could still be detected after all experiments.

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Ice nucleation efficiency of natural dust samples in the immersion mode

10.5194/acp-2016-337 ◽

2016 ◽

Author(s):

Lukas Kaufmann ◽

Claudia Marcolli ◽

Julian Hofer ◽

Valeria Pinti ◽

Christopher R. Hoyle ◽

...

Keyword(s):

Clay Minerals ◽

Active Sites ◽

Aqueous Suspension ◽

Mineralogical Composition ◽

Ice Nucleation ◽

Scanning Calorimetry ◽

Dust Collection ◽

Source Regions ◽

Nucleation Activity ◽

Ice Nucleation Activity

Abstract. Twelve natural dust samples from eight dust source regions on four continents were investigated with respect to their ice nucleation activity, revealing no significant differences between source regions. Dust collection sites were distributed across Africa, South America, the Middle East and Antarctica. Mineralogical compositions have been determined by means of X-ray diffraction. All samples proved to be mixtures of minerals, with major contributions from quartz, calcite, clay minerals, K-feldspars and (Na, Ca)-feldspars. Reference samples of these minerals were investigated with the same methods as the natural dust samples. Furthermore, Arizona Test Dust (ATD) was re-evaluated as a benchmark. Immersion freezing of emulsion and bulk samples was investigated by differential scanning calorimetry. For emulsion measurements, water droplets with a diameter of about 2 µm, containing different amounts of dust between 0.5 wt% and 50 wt% were cooled until all droplets were frozen. These measurements characterize the average freezing behaviour of particles, as they are sensitive to the average active sites present in a dust sample. In addition, bulk measurements were conducted with one single 1 mm diameter droplet consisting of a 5 wt% aqueous suspension of the dusts/minerals. These measurements allow the investigation of the best particles/sites available in a dust. All natural dusts except for the Antarctica and ATD samples froze in a remarkably narrow temperature range with the heterogeneously frozen fraction reaching 10 % between 244 and 250 K, 25 % between 242 and 246 K, and 50 % between 239 and 244 K. Bulk freezing occurred between 255 and 265 K. In contrast to the natural dusts, the reference minerals reveal ice nucleation temperatures with 2–3 times larger scatter. Calcite, dolomite, dolostone and muscovite can be considered inactive as ice nuclei (IN). For microcline samples 50 % heterogeneously frozen fraction occurred above 245 K for all tested suspension concentrations, and a microcline mineral showed bulk freezing temperatures even above 270 K. This makes microcline (KAlSi3O8) an exceptionally good IN, superior to all other analysed K-feldspars, (Na, Ca)-feldspars and the clay minerals. However, microcline is not abundant in the investigated natural dust samples. While K-feldspars were identified in five of the seven investigated natural source regions, only one sample contained microcline, and then only as a minor fraction. In summary, the mineralogical composition can explain the observed freezing behaviour of five of the investigated 12 natural dust samples, and partly for six samples, leaving the freezing efficiency of only one sample not easily explained in terms of its mineral reference components. While this suggests that mineralogical composition is a major determinant of ice nucleation ability, in practice most natural samples consist of a mixture of minerals, and this mixture seems to lead to remarkably similar ice nucleation abilities, regardless of their exact composition, so that global models, in a first approximation, may represent mineral dust as a single species with respect to ice nucleation activity. However, more sophisticated representations of ice nucleation by mineral dusts should rely on the mineralogical composition based on a source scheme of dust emissions.

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