Cloud and Atmosphere Metagenomics
Previously only considered a dispersal route for microorganisms, the atmosphere has recently been added to a long list of environments on Earth that could serve as bacterial habitats. Diverse bacterial communities are present in the atmosphere up to high altitudes as well as in cloud and fog droplets. By entering the droplets, airborne bacteria gain access to a liquid environment and diverse organic compounds and potentially affect atmospheric chemistry and physics.
The atmosphere is the most important conduit for bacterial dispersal. The mean global emissions from terrestrial surfaces amount to between 2.0*1016 and 5.6*1016 CFU per second (Burrows et al. 2009b). Emissions from marine surfaces are considered significantly lower. Marine bacteria get aerosolized through bubble bursting, whereas wind and temperature are proposed to be the main factors influencing uplift of bacteria from terrestrial surfaces...