Ice Nucleation Activity of Alpine Bioaerosol Emitted in Vicinity of a Birch Forest

In alpine environments, many plants, bacteria, and fungi contain ice nuclei (IN) that control freezing events, providing survival benefits. Once airborne, IN could trigger ice nucleation in cloud droplets, influencing the radiation budget and the hydrological cycle. To estimate the atmospheric relevance of alpine IN, investigations near emission sources are inevitable. In this study, we collected 14 aerosol samples over three days in August 2019 at a single site in the Austrian Alps, close to a forest of silver birches, which are known to release IN from their surface. Samples were taken during and after rainfall, as possible trigger of aerosol emission by an impactor and impinger at the ground level. In addition, we collected aerosol samples above the canopy using a rotary wing drone. Samples were analyzed for ice nucleation activity, and bioaerosols were characterized based on morphology and auto-fluorescence using microscopic techniques. We found high concentrations of IN below the canopy, with a freezing behavior similar to birch extracts. Sampled particles showed auto-fluorescent characteristics and the morphology strongly suggested the presence of cellular material. Moreover, some particles appeared to be coated with an organic film. To our knowledge, this is the first investigation of aerosol emission sources in alpine vegetation with a focus on birches.

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Development, Characterization and Testing of a Drone-based Sampling Method for Investigations of Ice-Nucleating Particles

10.5194/egusphere-egu2020-12099 ◽

2020 ◽

Author(s):

Paul Bieber ◽

Teresa M. Seifried ◽

Jürgen Gratzl ◽

Julia Burkart ◽

Anne Kasper-Giebl ◽

...

Keyword(s):

Hydrological Cycle ◽

Sampling Site ◽

Ice Nucleation ◽

Polystyrene Latex ◽

Environmental Data ◽

Small Scale ◽

Emission Sources ◽

Sampling Device ◽

Nucleation Activity ◽

Ice Nucleation Activity

<p>Terrestrial ecosystems can contribute various particles to the troposphere, some of which are known for their ice nucleation activity. Most of the land-surface in Europe is covered with forests and fields, representing potential sources of ice nucleation active bioaerosols in form of pollen grains, fungal spores and bacterial cells. The presence of biogenic ice-nucleating particles (INPs) in clouds leads to heterogeneous freezing events and therefore influences the hydrological cycle and the Earth&#8217;s climate. Many studies focus on measurements and characterizations of INPs in clouds using aircrafts or sample on ground with stationary devices. Less is known about the actual emission and transport to high tropospheric layers. We focused on the development of an efficient sampling device that can be attached to small scale drones, such as the DJI Phantom 4 model. The Drone-based Aerosol Particles Sampling Impinger/Impactor (DAPSI) system was developed to sample airborne INPs above emission sources. It includes a cascade impactor that collects particles with size resolution and a self-build impinging system that accumulates INPs in a sterile solution. Additionally, the system contains an electric sensor for environmental data records (temperature, relative humidity and air pressure) as well as an optical particle counter to monitor particular matter concentrations during flight times. This study leads through the building, characterization and test-campaign of DAPSI. We present a validation test, regarding the sampling effectivity to sample aerosols (polystyrene latex spheres and INPs) as well as results from the first field campaign which took place in a rural sampling site in the Austrian Alps. Fluorescence- and cryo-microscopic assays show auto-fluorescent particles and heterogeneous ice nucleation activity of DAPSI samples. We highlight the opportunity to use DAPSI with small un(wo)manned aerial vehicles during field campaigns to sample and identify biogenic INPs in vertical and spatial resolution above emission sources.</p>

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Comparing contact and immersion freezing from continuous flow diffusion chambers

10.5194/acp-2016-75 ◽

2016 ◽

Cited By ~ 1

Author(s):

Baban Nagare ◽

Claudia Marcolli ◽

André Welti ◽

Olaf Stetzer ◽

Ulrike Lohmann

Keyword(s):

Residence Time ◽

Continuous Flow ◽

Diffusion Chamber ◽

Ice Nucleation ◽

Freezing Process ◽

Electrical Mobility ◽

Cloud Droplets ◽

Immersion Freezing ◽

Nucleation Activity ◽

Ice Nucleation Activity

Abstract. Ice nucleating particles (INPs) in the atmosphere are responsible for glaciating cloud droplets between 237 K and 273 K. Different mechanisms of heterogeneous ice nucleation can compete under mixed-phase cloud conditions. Contact freezing is considered relevant because higher ice nucleation temperatures than for immersion freezing for the same INPs were observed. It has limitations because its efficiency depends on the number of collisions between cloud droplets and INPs. This study compares immersion and contact freezing efficiencies of three different INPs. The contact freezing data was obtained with the ETH CoLlision Ice Nucleation CHamber (CLINCH) using 80 μm diameter droplets which can interact with INPs for residence times of 2 s and 4 s in the chamber. The contact freezing efficiency was calculated by estimating the number of collisions between droplets and particles. Theoretical formulations of collision efficiencies gave too high freezing efficiencies for all investigated INPs, namely AgI particles with 200 nm electrical mobility diameter, 400 and 800 nm diameter ATD and kaolinite particles. Comparison of freezing efficiencies by contact and immersion freezing is therefore limited by the accuracy of collision efficiencies. The concentration of particles was 1000 cm−3 for ATD and kaolinite and 500, 1000, 2000 and 5000 cm−3 for AgI. For concentrations < 5000 cm−3, the droplets collect only one particle on average during their time in the chamber. For ATD and kaolinite particles, contact freezing efficiencies at 2 s residence time were smaller than at 4 s, which is in disagreement with a collisional contact freezing process but in accordance with contact freezing insideout or immersion freezing. For best comparison with contact freezing results, immersion freezing experiments of the same INPs were performed with the continuous flow diffusion chamber IMCA/ZINC for 3 s residence time. In IMCA/ZINC, each INP is activated into a droplet in IMCA and provides its surface for ice nucleation in the ZINC chamber. The comparison of contact and immersion freezing results did not confirm a general enhancement of freezing efficiency for contact compared with immersion freezing experiments. For AgI particles the onset of heterogeneous freezing in CLINCH was even shifted to lower temperatures compared with IMCA/ZINC. For ATD, freezing efficiencies for contact and immersion freezing experiments were similar. For kaolinite particles, contact freezing became detectable at higher temperatures than immersion freezing. Using contact angle information between water and the INP, it is discussed how the position of the INP in or on the droplets may influence its ice nucleation activity.

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Seasonal ice nucleation activity of water samples from alpine rivers and lakes in Obergurgl, Austria

The Science of The Total Environment ◽

10.1016/j.scitotenv.2021.149442 ◽

2021 ◽

pp. 149442

Author(s):

Philipp Baloh ◽

Regina Hanlon ◽

Christopher Anderson ◽

Eoin Dolan ◽

Gernot Pacholik ◽

...

Keyword(s):

Water Samples ◽

Ice Nucleation ◽

Rivers And Lakes ◽

Nucleation Activity ◽

Alpine Rivers ◽

Ice Nucleation Activity

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

Physical Chemistry Chemical Physics ◽

10.1039/d0cp04220j ◽

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.

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The occurrence of ice nucleation activity in pathogenic bacterial species

Archives of Phytopathology and Plant Protection ◽

10.1080/03235408.2012.724970 ◽

2012 ◽

Vol 45 (18) ◽

pp. 2202-2212

Author(s):

Horst Mittelstädt

Keyword(s):

Bacterial Species ◽

Ice Nucleation ◽

Nucleation Activity ◽

Ice Nucleation Activity

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Effects of atmospheric conditions on ice nucleation activity of <i>Pseudomonas</i>

Atmospheric Chemistry and Physics ◽

10.5194/acp-12-10667-2012 ◽

2012 ◽

Vol 12 (22) ◽

pp. 10667-10677 ◽

Cited By ~ 66

Author(s):

E. Attard ◽

H. Yang ◽

A.-M. Delort ◽

P. Amato ◽

U. Pöschl ◽

...

Keyword(s):

Environmental Factors ◽

Pseudomonas Syringae ◽

Ice Nucleation ◽

Acidic Ph ◽

Bacterial Cells ◽

Atmospheric Conditions ◽

Ice Nucleation Protein ◽

Ice Melt ◽

Nucleation Activity ◽

Ice Nucleation Activity

Abstract. Although ice nuclei from bacterial origin are known to be efficient at the highest temperatures known for ice catalysts, quantitative data are still needed to assess their role in cloud processes. Here we studied the effects of three typical cloud conditions (i) acidic pH (ii) NO2 and O3 exposure and (iii) UV-A exposure on the ice nucleation activity (INA) of four Pseudomonas strains. Three of the Pseudomonas syringae strains were isolated from cloud water and the phyllosphere and Pseudomonas fluorescens strain CGina-01 was isolated from Antarctic glacier ice melt. Among the three conditions tested, acidic pH caused the most significant effects on INA likely due to denaturation of the ice nucleation protein complex. Exposure to NO2 and O3 gases had no significant or only weak effects on the INA of two P. syringae strains whereas the INA of P. fluorescens CGina-01 was significantly affected. The INA of the third P. syringae strain showed variable responses to NO2 and O3 exposure. These differences in the INA of different Pseudomonas suggest that the response to atmospheric conditions could be strain-specific. After UV-A exposure, a substantial loss of viability of all four strains was observed whereas their INA decreased only slightly. This corroborates the notion that under certain conditions dead bacterial cells can maintain their INA. Overall, the negative effects of the three environmental factors on INA were more significant at the warmer temperatures. Our results suggest that in clouds where temperatures are near 0 °C, the importance of bacterial ice nucleation in precipitation processes could be reduced by some environmental factors.

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Ice nucleation activity identified in some phytopathogenic Fusarium species

Phytoprotection ◽

10.7202/706104ar ◽

2005 ◽

Vol 77 (2) ◽

pp. 83-92 ◽

Cited By ~ 29

Author(s):

C. Richard ◽

J.-G. Martin ◽

S. Pouleur

Keyword(s):

Fusarium Oxysporum ◽

Fusarium Species ◽

Freezing Temperature ◽

Ice Nucleation ◽

Free Living ◽

Factors Affecting ◽

Pure Cultures ◽

Nucleation Activity ◽

Ice Nucleation Activity ◽

Positive Controls

In order to know which species of Fusarium are ice nucleating and to determine the factors affecting their pathogenicity, ice nucleation activity (INA) was examined in Fusarium oxysporum, F. sporotrichioides, and F. tricinctum. Positive controls (lna+) used were F. acuminatum and F. avenaceum. The test for fungal INA was done with a simple and rapid tube nucleation assay. Twelve out of the 42 F. oxysporum isolates, and 8 out of 14 F. tricinctum isolates were lna+. No INA was detected in F sporotrichioides. In this test the threshold freezing temperature tended to increase with culture age, reaching a peak of -1°C in a few samples, which is as high as the warmest INA reported for bacteria, and higher than the INA detected in pure cultures of free-living fungi, lichen fungi, lichen algae and cyanobacteria. This is the first report of INA for F oxysporum.

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