Once underground, the experts grew biofilms on native rocks rich in iron and sulfur-bearing minerals. After six months, the team analyzed the microbial composition and physical properties of newly grown biofilms, as well as their distribution using microscopy, spectroscopy, and spatial modeling approaches.
Foreign life can exist in iron- and sulfur-rich environments underground similar to those of the Deep Mine Microbial Observatory
The analyzes, published in the journal Boundaries in microbiology, revealed hotspots where that biofilm was more poetic. These focal points correlate with iron-rich mineral grains in the rocks, emphasizing the mineral preferences for biofilm colonization.
“Our results show the strong spatial dependence of biofilm colonization on minerals in rock surfaces,” Caitlin Casar, first author of the study, said in a media statement. “We think this spatial dependence is due to the acquisition of microbes from minerals they colonize.”
According to Casar, these results show that host rock mineralogy is an important driver for the distribution of biofilms, which may help to improve the estimate of the microbial distribution of the Earth’s deep continental subsoil.
“Our findings may inform the contribution of biofilms to global feeding cycles, and also have astrobiological implications, as these findings provide insight into the distribution of biomass in a Mars analog system,” Casar said.
According to the researcher, extraterrestrial life can exist in iron- and sulfur-rich environments underground similar to those of DeMMO’s rock formations, where the microorganisms are protected from both radiation and extreme temperatures.