Heterogeneous ice nucleation activity of bacteria: new laboratory experiments at simulated cloud conditions
The ice nucleation activities of five different <i>Pseudomonas syringae</i>, <i>Pseudomonas viridiflava</i> and <i>Erwinia herbicola</i> bacterial species and of Snomax™ were investigated in the temperature range bet...
| Main Authors: | , , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2008-10-01
|
| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/5/1425/2008/bg-5-1425-2008.pdf |
| _version_ | 1829470057199042560 |
|---|---|
| author | O. Möhler D. G. Georgakopoulos C. E. Morris S. Benz V. Ebert S. Hunsmann H. Saathoff M. Schnaiter R. Wagner |
| author_facet | O. Möhler D. G. Georgakopoulos C. E. Morris S. Benz V. Ebert S. Hunsmann H. Saathoff M. Schnaiter R. Wagner |
| author_sort | O. Möhler |
| collection | DOAJ |
| description | The ice nucleation activities of five different <i>Pseudomonas syringae</i>, <i>Pseudomonas viridiflava</i> and <i>Erwinia herbicola</i> bacterial species and of Snomax™ were investigated in the temperature range between &minus;5 and &minus;15&deg;C. Water suspensions of these bacteria were directly sprayed into the cloud chamber of the AIDA facility of Forschungszentrum Karlsruhe at a temperature of &minus;5.7&deg;C. At this temperature, about 1% of the Snomax™ cells induced immersion freezing of the spray droplets before the droplets evaporated in the cloud chamber. The living cells didn't induce any detectable immersion freezing in the spray droplets at &minus;5.7&deg;C. After evaporation of the spray droplets the bacterial cells remained as aerosol particles in the cloud chamber and were exposed to typical cloud formation conditions in experiments with expansion cooling to about &minus;11&deg;C. During these experiments, the bacterial cells first acted as cloud condensation nuclei to form cloud droplets. Then, only a minor fraction of the cells acted as heterogeneous ice nuclei either in the condensation or the immersion mode. The results indicate that the bacteria investigated in the present study are mainly ice active in the temperature range between &minus;7 and &minus;11&deg;C with an ice nucleation (IN) active fraction of the order of 10<sup>&minus;4</sup>. In agreement to previous literature results, the ice nucleation efficiency of Snomax™ cells was much larger with an IN active fraction of 0.2 at temperatures around &minus;8&deg;C. |
| first_indexed | 2024-12-14T01:40:47Z |
| format | Article |
| id | doaj.art-270b651f08fd4b448c3bd733ea12d86a |
| institution | Directory Open Access Journal |
| issn | 1726-4170 1726-4189 |
| language | English |
| last_indexed | 2024-12-14T01:40:47Z |
| publishDate | 2008-10-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Biogeosciences |
| spelling | doaj.art-270b651f08fd4b448c3bd733ea12d86a2022-12-21T23:21:45ZengCopernicus PublicationsBiogeosciences1726-41701726-41892008-10-015514251435Heterogeneous ice nucleation activity of bacteria: new laboratory experiments at simulated cloud conditionsO. MöhlerD. G. GeorgakopoulosC. E. MorrisS. BenzV. EbertS. HunsmannH. SaathoffM. SchnaiterR. WagnerThe ice nucleation activities of five different <i>Pseudomonas syringae</i>, <i>Pseudomonas viridiflava</i> and <i>Erwinia herbicola</i> bacterial species and of Snomax™ were investigated in the temperature range between &minus;5 and &minus;15&deg;C. Water suspensions of these bacteria were directly sprayed into the cloud chamber of the AIDA facility of Forschungszentrum Karlsruhe at a temperature of &minus;5.7&deg;C. At this temperature, about 1% of the Snomax™ cells induced immersion freezing of the spray droplets before the droplets evaporated in the cloud chamber. The living cells didn't induce any detectable immersion freezing in the spray droplets at &minus;5.7&deg;C. After evaporation of the spray droplets the bacterial cells remained as aerosol particles in the cloud chamber and were exposed to typical cloud formation conditions in experiments with expansion cooling to about &minus;11&deg;C. During these experiments, the bacterial cells first acted as cloud condensation nuclei to form cloud droplets. Then, only a minor fraction of the cells acted as heterogeneous ice nuclei either in the condensation or the immersion mode. The results indicate that the bacteria investigated in the present study are mainly ice active in the temperature range between &minus;7 and &minus;11&deg;C with an ice nucleation (IN) active fraction of the order of 10<sup>&minus;4</sup>. In agreement to previous literature results, the ice nucleation efficiency of Snomax™ cells was much larger with an IN active fraction of 0.2 at temperatures around &minus;8&deg;C.http://www.biogeosciences.net/5/1425/2008/bg-5-1425-2008.pdf |
| spellingShingle | O. Möhler D. G. Georgakopoulos C. E. Morris S. Benz V. Ebert S. Hunsmann H. Saathoff M. Schnaiter R. Wagner Heterogeneous ice nucleation activity of bacteria: new laboratory experiments at simulated cloud conditions Biogeosciences |
| title | Heterogeneous ice nucleation activity of bacteria: new laboratory experiments at simulated cloud conditions |
| title_full | Heterogeneous ice nucleation activity of bacteria: new laboratory experiments at simulated cloud conditions |
| title_fullStr | Heterogeneous ice nucleation activity of bacteria: new laboratory experiments at simulated cloud conditions |
| title_full_unstemmed | Heterogeneous ice nucleation activity of bacteria: new laboratory experiments at simulated cloud conditions |
| title_short | Heterogeneous ice nucleation activity of bacteria: new laboratory experiments at simulated cloud conditions |
| title_sort | heterogeneous ice nucleation activity of bacteria new laboratory experiments at simulated cloud conditions |
| url | http://www.biogeosciences.net/5/1425/2008/bg-5-1425-2008.pdf |
| work_keys_str_mv | AT omohler heterogeneousicenucleationactivityofbacterianewlaboratoryexperimentsatsimulatedcloudconditions AT dggeorgakopoulos heterogeneousicenucleationactivityofbacterianewlaboratoryexperimentsatsimulatedcloudconditions AT cemorris heterogeneousicenucleationactivityofbacterianewlaboratoryexperimentsatsimulatedcloudconditions AT sbenz heterogeneousicenucleationactivityofbacterianewlaboratoryexperimentsatsimulatedcloudconditions AT vebert heterogeneousicenucleationactivityofbacterianewlaboratoryexperimentsatsimulatedcloudconditions AT shunsmann heterogeneousicenucleationactivityofbacterianewlaboratoryexperimentsatsimulatedcloudconditions AT hsaathoff heterogeneousicenucleationactivityofbacterianewlaboratoryexperimentsatsimulatedcloudconditions AT mschnaiter heterogeneousicenucleationactivityofbacterianewlaboratoryexperimentsatsimulatedcloudconditions AT rwagner heterogeneousicenucleationactivityofbacterianewlaboratoryexperimentsatsimulatedcloudconditions |