Microbes (including bacteria, archaea, and viruses) are ubiquitous on Earth and have been found under conditions where no animal can survive. Microbes known as extremophiles, inhabit extreme environments such as geothermal hot springs with pH less than 3, hypersaline environments with a salinity as high as 35%, and environments with extremely low concentrations of nutrients. One factor that can limit life is temperature; There is currently no known microbe that can tolerate temperatures higher than 122 ˚C. Hydrothermal systems display diverse and unpredictable conditions of extremely high temperatures and acidic pH, offering a range of environments that naturally test the limits of life as we know it. Microbial communities have been found within hydrothermal fluids, microbial mats on basaltic rock and chimneys, as well as within the neutrally buoyant hydrothermal plume, with varying energetic constraints on microbial activity and abundance. Moreover, hydrothermal systems are hypothesized to be the epicenters of the origins of life, making them ideal for studying evolutionary processes. They also display extreme conditions similar to what we could find on other planets.
The environmental conditions at Brothers volcano (study site of IODP Expedition 376 Brothers Arc Flux) provided a perfect setting to test the limits and adaptations of life. Preliminary analyses of the borehole fluids revealed temperatures up to 350˚C, pH as low as 1.8, higher salinity than in the upper water column, and very low concentrations of organic nutrients. Dr. Labonté’s research uses a combination of molecular approaches and cultivation to characterize the microbial communities’ diversity and interactions in hydrothermal systems to understand the life of extremophiles.
Dr. Jessica Labonté received her B.S. and M. Sc. from Laval University, and her Ph.D. from the University of British Columbia.
