We have long known about the microbial presence within clouds but until recently most of our data has been a result of cell culturing which as we all know: may not be representative of the microbial community. This study via the use of 16s amplicon sequencing sought to define both the taxonomic identity and microbial activity via extracted DNA and RNA respectively. Atmospheric samples were taken periodically above France via a modified weather probes. Each sample was screened for the relative amount of industrial contaminants to serve as a comparison to the negative control. This study found that on average 11000 to 21000 distinct OTUs which is comparable to that of a typical soil sample. Prokaryotes made up the majority of the sample with low amounts of eukaryotic fungal populations also being present. The source of this diversity has been attributed to aerosols particulate products that resulted from saphorytes. The Microbial richness of the aforementioned microbes was more pronounced in the contaminated samples. Between all the samples it was evident that the metabolic functions of these microbes were important for many hydrological mechanisms such as ice nucleation and ion mediated chemistry reactions which aid in both the formation of water droplets and the act of precipitation respectively. The microbiome of the cloud was found to be variable depending on the location and sensitive to changes in resources (such as industrial contaminants, temperature and topography) so further study should be allocated to defining, and in the far future, altering the clouds’ microbiome.
Recent studies have suggested that clouds could could act as a catalyst for environmental change. In fact the sheer abundance of microbes housed within a typical cloud is comparable to your everyday sample of dirt. Many of these microbes are important for key functions of the water cycle such as: aiding in the formation of water droplets, the initiation of precipitation and others. In fact, some of these microbial players have been shown to be partly responsible for the acceleration of climate change via the depletion of ozone. Indeed even bacteria which are responsible for creating methane, a potent greenhouse gas, were found in the clouds themselves, further aggravating climate change. While we have always known that there are microbes in the air, and by extension the clouds, we were ignorant as a species to the sheer magnitude and richness of the cloud microbiome. Above us in the skies are basically wastewater treatment plants that filter and control the flow of Earth’s lifeblood: water. Equipped with a better understanding of the microbial presence and hydrological implication there-in, mankind has made a significant step towards altering our weather and water cycles and perhaps in the far future this research could serve as the backbone of space exploration as we flush out variables involved in terraforming.
Pictures on my thing-link: compliments of Sophie