AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Living Microorganisms in Clouds
Mickaël Vaitilingom, Muriel Joly, Pierre Amato, Nicolas Gaiani, Laurent Deguillaume, Eleonore Attard, Martine Sancelme, ANNE-MARIE DELORT, Clermont Université, Institut de Chimie de Clermont-Ferrand
Abstract Number: 7 Working Group: Bioaerosols: Characterization and Environmental Impact
Abstract Despite the enormous volume they represent and the importance they have for Earth’s climate, clouds remain aquatic ecosystems where the microbiological features are still obscure. Between 2003 and 2010, 38 independent samples of cloud water were collected at the summit of the Puy de Dome mountain (1465 m asl, France) in order to study the microbial community with its qualitative and quantitative variability.
On average, 105 bacteria and 103 fungi per mL of cloud water are detected by DAPI labeling and microscopy. Less than 1% of the bacterial cells collected in cloud water are cultivated on a medium for drinking water (R2A) in aerobic conditions and absence of light. Concentrations of ADP / ATP measured in cloud water and their ratio are consistent with the existence of metabolic activity in the cloud droplets.
More than 500 strains of bacteria or yeasts were isolated and identified by 16S or 26S rRNA genes sequencing. Most frequent genera include Pseudomonas, Sphingomonas and Frigoribacterium for bacteria and Udeniomyces, Dioszegia and Cryptococcus for yeasts. These strains present high similarities to those isolated from the vegetation, soils or other aquatic environments. Interestingly, most of the Sphingomonas strains isolated from cloud water are located within a small and specific phylogenetic cluster that gathered species isolated from the atmosphere.
Vaïtilingom M. et al. (2012) Long-term features of cloud microbiology at the Puy de Dôme (France). Atmospheric Environment 56, 88-100.