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Biological ice nucleators at tropospheric cloud height (4th year)

English title Biological ice nucleators at tropospheric cloud height (4th year)
Applicant Conen Franz
Number 159194
Funding scheme Project funding (Div. I-III)
Research institution Institut für Umweltgeowissenschaften Universität Basel
Institution of higher education University of Basel - BS
Main discipline Climatology. Atmospherical Chemistry, Aeronomy
Start/End 01.09.2015 - 31.08.2016
Approved amount 67'046.00
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All Disciplines (2)

Discipline
Climatology. Atmospherical Chemistry, Aeronomy
Environmental Research

Keywords (5)

Pseudomonas syringae; ice nucleation; atmosphere; aerosol; biological

Lay Summary (German)

Lead
Wolken sind flüchtige Objekte, deren Entstehung und Entwicklung, wie zum Beispiel Niederschlagsbildung und Auflösung, von einer Reihe physikalischer, chemischer und biologischer Faktoren abhängt. Die Abbildung dieser Faktoren und Vorgänge stellen die grösste Unsicherheit in Klimamodellen dar.
Lay summary

Einen eindeutigen biologischen Einfluss auf die Wolkenbildung hat die Transpiration der Vegetation, durch die Wasserdampf vom Boden in die Atmosphäre gelangt, wo er aufsteigt, abkühlt und kondensiert, also Wolken bildet. Einen weit weniger bekannten Einfluss haben kleinste biologische Partikel, wie Bakterien die auf Blattoberflächen wachsen, durch Wind losgelöst und in der Atmosphäre verteilt werden können. Einige dieser Bakterien, aber auch andere biologische Partikel, haben die Fähigkeit Wasser bei einer Temperatur nahe unter 0 oC zum Gefrieren zu bringen. Ohne diese Partikel würde die Eisbildung in Wolken erst bei Temperaturen unter etwa -10 oC einsetzen, verursacht durch mineralische Partikel. Die Eisbildung ist, zumindest in den mittleren Breiten, ein häufiger Auslöser von Niederschlagsereignissen. In diesem Projekt werten wir Untersuchungen zu biologischen Partikeln aus, die wir in den vergangenen drei Jahren auf dem Jungfraujoch gemacht haben. Wir gehen der Frage nach, welchen Ursprungs diese Partikel sind, welche Faktoren ihre Abundanz in der Atmosphäre bestimmen, sowie ob und unter welchen Umständen sie für die Eisbildung in Wolken limitierend sein könnten.

Direct link to Lay Summary Last update: 17.12.2014

Responsible applicant and co-applicants

Employees

Publications

Publication
Ice nucleators, bacterial cells and <i>Pseudomonas syringae</i> in precipitation at Jungfraujoch
Stopelli Emiliano, Conen Franz, Guilbaud Caroline, Zopfi Jakob, Alewell Christine, Morris Cindy E. (2017), Ice nucleators, bacterial cells and <i>Pseudomonas syringae</i> in precipitation at Jungfraujoch, in Biogeosciences, 14(5), 1189-1196.
Clues that decaying leaves enrich Arctic air with ice nucleating particles
Conen F., Stopelli E., Zimmermann L. (2016), Clues that decaying leaves enrich Arctic air with ice nucleating particles, in Atmospheric Environment, 129, 91-94.
Predicting abundance and variability of ice nucleating particles in precipitation at the high-altitude observatory Jungfraujoch
Stopelli Emiliano, Conen Franz, Morris Cindy, Herrmann Erik, Henne Stephan, Steinbacher Martin, Alewell Christine (2016), Predicting abundance and variability of ice nucleating particles in precipitation at the high-altitude observatory Jungfraujoch, in Atmospheric Chemistry and Physics, 16, 8341-8351.
Ice nucleation active particles are efficiently removed by precipitating clouds
Stopelli Emiliano, Conen Franz, Morris Cindy E., Herrmann Erik, Bukowiecki Nicolas, Alewell Christine (2015), Ice nucleation active particles are efficiently removed by precipitating clouds, in Scientific Reports, 5, 16433.

Collaboration

Group / person Country
Types of collaboration
Plant Pathology Research, Institut national de la recherche agronomique (INRA) France (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
- Exchange of personnel
Aerosol Physics Group, Laboratory of Atmospheric Chemistry, Paul Scherrer Institute (PSI) Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Air Pollution / Environmental Technology, Empa Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
Talk at Max Planck Institute of Chemistry, Mainz Individual talk Biological ice nucleating particles at tropospheric cloud height 27.07.2016 MPIC, Mainz, Germany, Germany Stopelli Emiliano;
EGU meeting 2016- session AS 1.27 Poster Predicting the abundance of ice nucleating particles of biological origin in precipitation 19.04.2016 Vienna, Austria Stopelli Emiliano;
EGU meeting 2016- session AS 1.27 Poster Landscape-precipitation feedback mediated by ice nuclei- an example from the Arctic 19.04.2016 Vienna, Austria Stopelli Emiliano;
Mycrophysics of ice clouds 2016 Talk given at a conference Exploring the sources of variability in ice nucleating particles of biological origin 16.04.2016 Vienna, Austria Stopelli Emiliano;
Microorganisms at the Interface Land-Atmosphere and Feedbacks (MILAF) 2016 Talk given at a conference Making the most out of the world’s observatories of atmospheric particles 17.03.2016 Bolzano/Bozen, Italy Stopelli Emiliano; Conen Franz;
Talk at ISAC-CNR, Bologna Individual talk Variations of biological ice nucleating particles in precipitation 27.11.2015 Bologna, Italy Stopelli Emiliano;
Swiss Geoscience Meeting 2015 Poster Ice nuclei and the landscape-precipitation feedback, an example from the Arctic 21.11.2015 Basel, Switzerland Stopelli Emiliano;


Communication with the public

Communication Title Media Place Year
Talks/events/exhibitions UniNacht. Experiment: Was braucht man damit es schneit? Western Switzerland 2015

Awards

Title Year
Prix de Quervain 2017
Outstanding Student Poster and PICO (OSPP) Award, EGU General Assembly 2016, for the poster "Landscape-precipitation feedback mediated by ice nuclei - an example from the Arctic" 2016

Associated projects

Number Title Start Funding scheme
169620 Relevance of biological particles in atmospheric ice formation at moderate supercooling 01.04.2017 Project funding (Div. I-III)
137638 Measurement-based verification of regional emissions of halogenated greenhouse gases 01.04.2012 Project funding (Div. I-III)
140228 Biological ice nucleators at tropospheric cloud height 01.09.2012 Project funding (Div. I-III)

Abstract

The objective of this research project is to shed light on the relevance of biological ice nucleation for the development of precipitation, inside the wider frame of the debate on climate change and land use interaction. The activity started in 2012 with the familiarisation of our PhD student, Emiliano Stopelli, with the technique of immersion freezing for ice nuclei (IN) detection. This led to a constant improvement of the method resulting in the finalisation of a new apparatus (LINDA) and the publication of a paper describing the potential of this apparatus for research on biological IN. The first year of field observation (11 sampling campaigns, total of 123 samples) of IN in fresh snow samples collected at Jungfraujoch is completed. Some more time than what had been planned was necessary, mainly to implement the methodologies employed in field and to carry out all the samplings. Additional measurements were done on the samples, including the analysis of stable water isotopes content (18O and 2H) and the direct counting of microorganism with fluorescence microscopy. Information on meteorological parameters, potential source region of air masses, trace gas concentrations and aerosol parameters was collected for the sampling periods. The amount and complexity of data collected, brought us to resort to different statistical approaches to gain a maximum of insight from the observations. The analysis of the whole set of data is almost complete and a second manuscript is close to submission. A strong interest of students in this research led to the parallel development of a total of 2 MSc and 1 BSc thesis projects. Biological IN activity is constituted by a complex mosaic of living and dead material from different sources, which requires a series of treatments considering the major classes of biological IN. Finding a suitable method for biological IN characterisation proved less simple than expected and is our main reason to apply for an extension of the project. The initially planned approach was based on the subsequent treatment of samples with polyglycerol, lysozyme and heat (90 °C), to progressively distinguish between the activity of Pseudomonas syringae, other bacterial and fungal IN and organic substances. Recent literature, combined with the laboratory assays we carried out, showed that results obtained with lysozyme and with polyglycerol are unreliable and heat treatment (90 °C) is too unspecific in deactivating IN active in the temperature range of interest. Therefore, we developed a completely new approach based on two more moderate heat treatments (40 °C; 80 °C) combined with three size separations (< 5 µm,< 1.2 µm, < 0.22 µm). Testing the effectiveness of the new approach with laboratory assays on pure substances (e.g. soil dust, pure clay, bacteria) has been time consuming. Currently, we are testing our new approach in the field. To detect P. syringae, we are comparing two different methods at Jungfraujoch: one is based on direct plating and the other on enrichment cultures prior to DNA extraction and analysis. We expect our new approaches to provide great new insights into the atmospheric dynamics and composition of biological IN. Yet, a 4th year of funding will be necessary to complete the analysis of the observations that have started and publish all the results obtained.
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