Microorganisms can play big roles in geological processes. Previous studies have shown that microbes’ metabolic activities can alter their microenvironment and sometimes induce processes such as mineral precipitation and dissolution. However, many questions remain about how microbes interact with their surrounding ecosystem, particularly in extreme environments.
In a recent PLOS ONE study, Maria Eugenia Farias and colleagues investigated the microbial environment of Laguna La Brava, Salar de Atacama in Chile. This lake has microbial communities growing in extreme conditions, including high salinity, intense exposure to the sun’s rays, and high levels of metals such as lithium, arsenic, magnesium, and calcium. The researchers collected and compared bacterial and water samples from several distinct ecosystems near the lake, including a multi-layered sheet of microorganisms known as a microbial mat, a rock carbonate structure, and a hard compact mass formed from precipitation.
The researchers found that Euryarchaeota, Crenarchaeota, Acetothermia, Firmicutes and Planctomycetes were the most abundant bacterial and archaeal groups. Surprisingly, they found little or no cyanobacteria in any of the ecosystems. Since cyanobacteria are usually an important producer of microbial mats, the authors suggest that there may be other microorganisms that are responsible for precipitating minerals in these ecosystems. Further research at these sites might reveal previously unknown species, some of which could have potential applications in biotech.
Reference: Farias ME, Rasuk MC, Gallagher KL, Contreras M, Kurth D, Fernandez AB, et al. (2017) Prokaryotic diversity and biogeochemical characteristics of benthic microbial ecosystems at La Brava, a hypersaline lake at Salar de Atacama, Chile. PLoS ONE 12(11): e0186867. https://doi.org/10.1371/journal.pone.0186867
Image Credit: Farias et al (2017)