scholarly journals Spores of many common airborne fungi reveal no ice nucleation activity in oil immersion freezing experiments

2013 ◽  
Vol 10 (12) ◽  
pp. 8083-8091 ◽  
Author(s):  
B. G. Pummer ◽  
L. Atanasova ◽  
H. Bauer ◽  
J. Bernardi ◽  
I. S. Druzhinina ◽  
...  
Keyword(s):  
Fungal Spores ◽  
Airborne Fungi ◽  
Ice Nucleation ◽  
Freezing Stress ◽  
Fungal Strains ◽  
Biological Aerosols ◽  
Ice Nuclei ◽  
Immersion Freezing ◽  
Oil Emulsions ◽  
Ice Nucleation Activity

Abstract. Fungal spores are ubiquitous biological aerosols, which are considered to act as ice nuclei. In this study the ice nucleation (IN) activity of spores harvested from 29 fungal strains belonging to 21 different species was tested in the immersion freezing mode by microscopic observation of water-in-oil emulsions. Spores of 8 of these strains were also investigated in a microdroplet freezing array instrument. The focus was laid on species of economical, ecological or sanitary significance. Besides common molds (Ascomycota), some representatives of the widespread group of mushrooms (Basidiomycota) were also investigated. Fusarium avenaceum was the only sample showing IN activity at relatively high temperatures (about 264 K), while the other investigated fungal spores showed no freezing above 248 K. Many of the samples indeed froze at homogeneous ice nucleation temperatures (about 237 K). In combination with other studies, this suggests that only a limited number of species may act as atmospheric ice nuclei. This would be analogous to what is already known for the bacterial ice nuclei. Apart from that, we selected a set of fungal strains from different sites and exposed them to occasional freezing stress during their cultivation. This was in order to test if the exposure to a cold environment encourages the expression of ice nuclei during growth as a way of adaptation. Although the total protein expression was altered by this treatment, it had no significant impact on the IN activity.

scholarly journals Spores of most common airborne fungi reveal no ice nucleation activity

2013 ◽  
Vol 10 (6) ◽  
pp. 10125-10141 ◽  
Author(s):  
B. G. Pummer ◽  
L. Atanasova ◽  
H. Bauer ◽  
J. Bernardi ◽  
I. S. Druzhinina ◽  
...  
Keyword(s):  
Fungal Spores ◽  
Airborne Fungi ◽  
Ice Nucleation ◽  
Freezing Stress ◽  
Oil Emulsion ◽  
Biological Aerosols ◽  
Subzero Temperatures ◽  
Immersion Freezing ◽  
Ice Nucleation Activity ◽  
First Time

Abstract. Fungal spores are ubiquitous biological aerosols, which are considered to show ice nucleation (IN) activity. In this study the respective IN activity was tested in oil emulsion in the immersion freezing mode. The focus was laid on species of economical, ecological or sanitary significance. For the first time, not only common moulds, but also edible mushrooms (Basidiomycota, Agaricomycetes) were investigated, as they contribute massively to the total amount of fungal spores in the atmosphere. Only Fusarium avenaceum showed freezing events at low subzero-temperatures, while the other investigated fungal spores showed no significant IN activity. Furthermore, we selected a set of fungal strains from different sites and exposed them to occasional freezing stress during cultivation. Although the total protein expression was altered by this treatment, it had no significant impact on the IN activity.

scholarly journals Deposition and immersion-mode nucleation of ice by three distinct samples of volcanic ash

2015 ◽  
Vol 15 (13) ◽  
pp. 7523-7536 ◽  
Author(s):  
G. P. Schill ◽  
K. Genareau ◽  
M. A. Tolbert
Keyword(s):  
Volcanic Ash ◽  
Mineral Dust ◽  
Global Climate ◽  
Volcanic Eruptions ◽  
Silica Content ◽  
Ice Nucleation ◽  
Ice Nuclei ◽  
Immersion Freezing ◽  
Nucleation Activity ◽  
Ice Nucleation Activity

Abstract. Ice nucleation of volcanic ash controls both ash aggregation and cloud glaciation, which affect atmospheric transport and global climate. Previously, it has been suggested that there is one characteristic ice nucleation efficiency for all volcanic ash, regardless of its composition, when accounting for surface area; however, this claim is derived from data from only two volcanic eruptions. In this work, we have studied the depositional and immersion freezing efficiency of three distinct samples of volcanic ash using Raman microscopy coupled to an environmental cell. Ash from the Fuego (basaltic ash, Guatemala), Soufrière Hills (andesitic ash, Montserrat), and Taupo (Oruanui eruption, rhyolitic ash, New Zealand) volcanoes were chosen to represent different geographical locations and silica content. All ash samples were quantitatively analyzed for both percent crystallinity and mineralogy using X-ray diffraction. In the present study, we find that all three samples of volcanic ash are excellent depositional ice nuclei, nucleating ice from 225 to 235 K at ice saturation ratios of 1.05 ± 0.01, comparable to the mineral dust proxy kaolinite. Since depositional ice nucleation will be more important at colder temperatures, fine volcanic ash may represent a global source of cold-cloud ice nuclei. For immersion freezing relevant to mixed-phase clouds, however, only the Oruanui ash exhibited appreciable heterogeneous ice nucleation activity. Similar to recent studies on mineral dust, we suggest that the mineralogy of volcanic ash may dictate its ice nucleation activity in the immersion mode.

scholarly journals The contribution of fungal spores and bacteria to regional and global aerosol number and ice nucleation immersion freezing rates

2013 ◽  
Vol 13 (12) ◽  
pp. 32459-32481 ◽  
Author(s):  
D. V. Spracklen ◽  
C. L. Heald
Keyword(s):  
Cloud Condensation Nuclei ◽  
Fungal Spores ◽  
Ice Nucleation ◽  
Model Studies ◽  
Modelling Studies ◽  
Climate Interactions ◽  
Immersion Freezing ◽  
Simulated Surface ◽  
Mixed Phase Clouds ◽  
Ice Nucleation Activity

Abstract. Primary biological aerosol particles (PBAP) may play an important role in aerosol–climate interactions, in particular through affecting ice formation in mixed phase clouds. However, the role of PBAP is poorly understood because the sources and distribution of PBAP in the atmosphere are not well quantified. Here we include emissions of fungal spores and bacteria in a global aerosol microphysics model and explore their contribution to concentrations of supermicron particle number, cloud condensation nuclei (CCN) and immersion freezing rates. Simulated surface annual mean concentrations of fungal spores are ~2.5 × 104 m−3 over continental midlatiudes and 1 × 105 m−3 over tropical forests. Simulated surface concentrations of bacteria are 2.5 × 104 m−3 over most continental regions and 5 × 104 m−3 over grasslands of central Asia and North America. These simulated surface number concentrations of fungal spores and bacteria are broadly in agreement with the limited available observations. We find that fungal spores and bacteria contribute 8% and 5% respectively to simulated continental surface mean supermicron number concentrations, but have very limited impact on CCN concentrations, altering regional concentrations by less than 1%. In agreement with previous global modelling studies we find that fungal spores and bacteria contribute very little (3 × 10−3 % even when we assume upper limits for ice nucleation activity) to global average immersion freezing ice nucleation rates, which are dominated by soot and dust. However, at lower altitudes (400 hPa to 600 hPa), where warmer temperatures mean that soot and dust may not nucleate ice, we find that PBAP controls the immersion freezing ice nucleation rate. This demonstrates that PBAP can be of regional importance for IN formation, in agreement with case study observations but in contrast to recent global model studies that have concluded PBAP are unimportant as ice nuclei.

scholarly journals Empirical formulation for multiple groups of primary biological ice nucleating particles from field observations over Amazonia

2021 ◽  
Author(s):  
Sachin Patade ◽  
Vaughan T. J. Phillips ◽  
Pierre Amato ◽  
Heinz G. Bingemer ◽  
Susannah M. Burrows ◽  
...  
Keyword(s):  
Surface Area ◽  
Fungal Spores ◽  
Ice Nucleation ◽  
Field Observations ◽  
Ice Nuclei ◽  
Viral Particles ◽  
Multiple Groups ◽  
Ice Nucleation Activity ◽  
Bacterial Groups ◽  
Biological Component

AbstractTo resolve the various types of biological ice nuclei (IN) with atmospheric models, an extension of the empirical parameterization (EP) (Phillips et al. 2008; 2013) is proposed to predict the active IN from multiple groups of primary biological aerosol particles (PBAPs). Our approach is to utilize coincident observations of PBAP sizes, concentrations, biological composition, and ice-nucleating ability. The parameterization organizes the PBAPs into five basic groups: fungal spores, bacteria, pollen, viral particles, plant/animal detritus, algae, and their respective fragments. This new biological component of the EP was constructed by fitting predicted concentrations of PBAP IN to those observed at the Amazon Tall Tower Observatory (ATTO) site located in the central Amazon. The fitting parameters for pollen and viral particles, plant/animal detritus, which are much less active as IN than fungal and bacterial groups, are constrained based on their ice nucleation activity from the literature. The parameterization has empirically derived dependencies on the surface area of each group (except algae), and the effects of variability in their mean sizes and number concentrations are represented via their influences on the surface area. The concentration of active algal IN is estimated from literature-based measurements.Predictions of this new biological component of the EP are consistent with previous laboratory and field observations not used in its construction. The EP scheme was implemented in a 0D parcel model. It confirms that biological IN account for most of the total IN activation at temperatures warmer than −20°C and at colder temperatures dust and soot become increasingly more important to ice nucleation.

scholarly journals Deposition and immersion mode nucleation of ice by three distinct samples of volcanic ash using Raman spectroscopy

2015 ◽  
Vol 15 (2) ◽  
pp. 1385-1420 ◽  
Author(s):  
G. P. Schill ◽  
K. Genareau ◽  
M. A. Tolbert
Keyword(s):  
Volcanic Ash ◽  
Mineral Dust ◽  
Global Climate ◽  
Volcanic Eruptions ◽  
Silica Content ◽  
Ice Nucleation ◽  
Ice Nuclei ◽  
Immersion Freezing ◽  
Nucleation Activity ◽  
Ice Nucleation Activity

Abstract. Ice nucleation on volcanic ash controls both ash aggregation and cloud glaciation, which affect atmospheric transport and global climate. Previously, it has been suggested that there is one characteristic ice nucleation efficiency for all volcanic ash, regardless of its composition, when accounting for surface area; however, this claim is derived from data from only two volcanic eruptions. In this work, we have studied the depositional and immersion freezing efficiency of three distinct samples of volcanic ash using Raman Microscopy coupled to an environmental cell. Ash from the Fuego (basaltic ash, Guatemala), Soufrière Hills (andesitic ash, Montserrat), and Taupo (Oruanui euption, rhyolitic ash, New Zealand) volcanoes were chosen to represent different geographical locations and silica content. All ash samples were quantitatively analyzed for both percent crystallinity and mineralogy using X-ray diffraction. In the present study, we find that all three samples of volcanic ash are excellent depositional ice nuclei, nucleating ice from 225–235 K at ice saturation ratios of 1.05 ± 0.01, comparable to the mineral dust proxy kaolinite. Since depositional ice nucleation will be more important at colder temperatures, fine volcanic ash may represent a global source of cold-cloud ice nuclei. For immersion freezing relevant to mixed-phase clouds, however, only the Oruanui ash exhibited heterogeneous ice nucleation activity. Similar to recent studies on mineral dust, we suggest that the mineralogy of volcanic ash may dictate its ice nucleation activity in the immersion mode.

scholarly journals The contribution of fungal spores and bacteria to regional and global aerosol number and ice nucleation immersion freezing rates

2014 ◽  
Vol 14 (17) ◽  
pp. 9051-9059 ◽  
Author(s):  
D. V. Spracklen ◽  
C. L. Heald
Keyword(s):  
Cloud Condensation Nuclei ◽  
Fungal Spores ◽  
Ice Nucleation ◽  
Modelling Studies ◽  
Climate Interactions ◽  
Immersion Freezing ◽  
Simulated Surface ◽  
Global Modelling ◽  
Mixed Phase Clouds ◽  
Ice Nucleation Activity

Abstract. Primary biological aerosol particles (PBAPs) may play an important role in aerosol–climate interactions, in particular by affecting ice formation in mixed phase clouds. However, the role of PBAPs is poorly understood because the sources and distribution of PBAPs in the atmosphere are not well quantified. Here we include emissions of fungal spores and bacteria in a global aerosol microphysics model and explore their contribution to concentrations of supermicron particle number, cloud condensation nuclei (CCN) and immersion freezing rates. Simulated surface annual mean concentrations of fungal spores are ~ 2.5 × 104 m−3 over continental midlatitudes and 1 × 105 m−3 over tropical forests. Simulated surface concentrations of bacteria are 2.5 × 104 m−3 over most continental regions and 5 × 104 m−3 over grasslands of central Asia and North America. These simulated surface number concentrations of fungal spores and bacteria are broadly in agreement with the limited available observations. We find that fungal spores and bacteria contribute 8 and 5% respectively to simulated continental surface mean supermicron number concentrations, but have very limited impact on CCN concentrations, altering regional concentrations by less than 1%. In agreement with previous global modelling studies, we find that fungal spores and bacteria contribute very little (3 × 10−3%, even when we assume upper limits for ice nucleation activity) to global average immersion freezing ice nucleation rates, which are dominated by soot and dust. However, at lower altitudes (400 to 600 hPa), where warmer temperatures mean that soot and dust may not nucleate ice, we find that PBAP controls the immersion freezing ice nucleation rate. This demonstrates that PBAPs can be of regional importance for IN formation, in agreement with case study observations.

scholarly journals Urediospores of rust fungi are ice nucleation active at > −10 °C and harbor ice nucleation active bacteria

2013 ◽  
Vol 13 (8) ◽  
pp. 4223-4233 ◽  
Author(s):  
C. E. Morris ◽  
D. C. Sands ◽  
C. Glaux ◽  
J. Samsatly ◽  
S. Asaad ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
Ice Nucleation ◽  
Rust Fungi ◽  
Plant Diseases ◽  
Ice Nuclei ◽  
Ice Nucleators ◽  
The Usa ◽  
Immersion Freezing ◽  
Nucleation Activity ◽  
Ice Nucleation Activity

Abstract. Various features of the biology of the rust fungi and of the epidemiology of the plant diseases they cause illustrate the important role of rainfall in their life history. Based on this insight we have characterized the ice nucleation activity (INA) of the aerially disseminated spores (urediospores) of this group of fungi. Urediospores of this obligate plant parasite were collected from natural infections of 7 species of weeds in France, from coffee in Brazil and from field and greenhouse-grown wheat in France, the USA, Turkey and Syria. Immersion freezing was used to determine freezing onset temperatures and the abundance of ice nuclei in suspensions of washed spores. Microbiological analyses of spores from France, the USA and Brazil, and subsequent tests of the ice nucleation activity of the bacteria associated with spores were deployed to quantify the contribution of bacteria to the ice nucleation activity of the spores. All samples of spores were ice nucleation active, having freezing onset temperatures as high as −4 °C. Spores in most of the samples carried cells of ice nucleation-active strains of the bacterium Pseudomonas syringae (at rates of less than 1 bacterial cell per 100 urediospores), but bacterial INA accounted for only a small fraction of the INA observed in spore suspensions. Changes in the INA of spore suspensions after treatment with lysozyme suggest that the INA of urediospores involves a polysaccharide. Based on data from the literature, we have estimated the concentrations of urediospores in air at cloud height and in rainfall. These quantities are very similar to those reported for other biological ice nucleators in these same substrates. However, at cloud level convective activity leads to widely varying concentrations of particles of surface origin, so that mean concentrations can underestimate their possible effects on clouds. We propose that spatial and temporal concentrations of biological ice nucleators active at temperatures > −10 °C and the specific conditions under which they can influence cloud glaciation need to be further evaluated so as to understand how evolutionary processes could have positively selected for INA.

Ice nucleation activity of iron oxides via immersion freezing and an examination of the high ice nucleation activity of FeO

2021 ◽  
Vol 23 (5) ◽  
pp. 3565-3573
Author(s):  
Esther Chong ◽  
Katherine E. Marak ◽  
Yang Li ◽  
Miriam Arak Freedman
Keyword(s):  
Iron Oxides ◽  
Functional Groups ◽  
Ice Nucleation ◽  
Mechanical Processing ◽  
Immersion Freezing ◽  
Nucleation Activity ◽  
Ice Nucleation Activity

FeO has enhanced ice nucleation activity due to functional groups that are exposed upon mechanical processing.

scholarly journals Ice nucleation efficiency of AgI: review and new insights

2016 ◽  
Author(s):  
Claudia Marcolli ◽  
Baban Nagare ◽  
André Welti ◽  
Ulrike Lohmann
Keyword(s):  
Water Saturation ◽  
Experimental Studies ◽  
Freezing Temperature ◽  
Nucleating Agent ◽  
Companion Paper ◽  
Chem Phys ◽  
Ice Nucleation ◽  
Lattice Match ◽  
Ice Nuclei ◽  
Immersion Freezing

Abstract. AgI is one of the best investigated ice nuclei. It has relevance for the atmosphere since it is used for glaciogenic cloud seeding. Theoretical and experimental studies over the last sixty years provide a complex picture of silver iodide as ice nucleating agent with conflicting and inconsistent results. This review compares experimental ice nucleation studies in order to analyse the factors that influence the ice nucleation ability of AgI. We have performed experiments to compare contact and immersion freezing by AgI. This is one of three papers that describe and analyse contact and immersion freezing experiments with AgI. In Nagare et al. (Nagare, B., Marcolli, C., Stetzer, O., and Lohmann, U.: Comparison of measured and calculated collision efficiencies at low temperatures, Atmos. Chem. Phys., 15, 13759–13776, doi:10.5194/acp-15-13759-2015, 2015) collision efficiencies based on contact freezing experiments with AgI are determined and compared with theoretical formulations. In a companion paper, contact freezing experiments are compared with immersion freezing experiments conducted with AgI, kaolinite, and ATD as ice nuclei. The following picture emerges from this analysis: The ice nucleation ability of AgI seems to be enhanced when the AgI particle is on the surface of a droplet, which is indeed the position that a particle takes when it can freely move in a droplet. Ice nucleation by particles with surfaces exposed to air, depends on water adsorption. AgI surfaces seem to be most efficient as ice nuclei when they are exposed to relative humidity at or even above water saturation. For AgI particles that are totally immersed in water, the freezing temperature increases with increasing AgI surface area. Higher threshold freezing temperature seem to correlate with improved lattice matches as can be seen for AgI-AgCl solid solutions and 3AgI•NH4I•6H2O, which have slightly better lattice matches with ice than AgI and also higher threshold freezing temperatures. However, the effect of a good lattice match is annihilated when the surfaces have charges. Also, the ice nucleation ability seems to decrease during dissolution of AgI particles. This introduces an additional history and time dependence of ice nucleation in cloud chambers with short residence times.

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

2012 ◽  
Vol 12 (5) ◽  
pp. 2541-2550 ◽  
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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