English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

. Biological particles, including bacteria and bacterial fragments, have beenof much interest due to the special ability of some to nucleate ice atmodestly supercooled temperatures. This paper presents results from a recentstudy conducted on two strains of cultivated bacteria which suggest thatbacterial fragments mixed with agar, and not whole bacterial cells, serve ascloud condensation nuclei (CCN). Due to the absence of whole bacteria cellsin droplets, they are unable to serve as ice nucleating particles (INPs) inthe immersion mode under the experimental conditions. Experiments wereconducted at the Aerosol Interaction and Dynamics in the Atmosphere (AIDA)cloud chamber at the Karlsruhe Institute of Technology (KIT) by injectingbacteria-containing aerosol samples into the cloud chamber and inducing cloudformation by expansion over a temperature range of −5 to −12 ∘ C.Cloud droplets and ice crystals were sampled through a pumped counterflowvirtual impactor inlet (PCVI) and their residuals were characterized with asingle particle mass spectrometer (miniSPLAT). The size distribution of theoverall aerosol was bimodal, with a large particle mode composed of intactbacteria and a mode of smaller particles composed of bacterial fragmentsmixed with agar that were present in higher concentrations. Results fromthree expansions with two bacterial strains indicate that the cloud dropletresiduals had virtually the same size distribution as the smaller particlesize mode and had mass spectra that closely matched those of bacterialfragments mixed with agar. The characterization of ice residuals that weresampled through an ice-selecting PCVI (IS-PCVI) also shows that the sameparticles that activate to form cloud droplets, bacteria fragments mixed withagar, were the only particle type observed in ice residuals. These resultsindicate that the unavoidable presence of agar or other growth media inall laboratory studies conducted on cultivated bacteria can greatlyaffect the results and needs to be considered when interpreting CCN and INactivation data.

Activation of intact bacteria and bacterial fragments mixed with agar as cloud droplets and ice crystals in cloud chamber experiments