Incorporating Microbes into Laboratory-Grown Chimneys for Hydrothermal Microbiology Experiments

: Hydrothermal chimneys are diverse habitats for microbial life in the deep sea; these systems are of interest to microbiologists since changes in vent chemistry and activity can drive changes in the metabolic landscape of the local microbial communities and to astrobiologists since hydrothermal systems have been proposed as habitable environments on ocean worlds. Injection chemical garden experiments have been used extensively to simulate the energy and reactivity of prebiotic hydrothermal chimneys in an early Earth context; however, incorporating microbes into a laboratory-grown hydrothermal chimney has not been attempted. We present the results of a pilot study where a marine organism species (Vibrio harveyi) was successfully incorporated into a modified early Earth hydrothermal iron hydroxide chimney simulation. Fluorescence microscopy demonstrated that the microbes injected into the lab-grown chimney were present and detectable on the chimney walls and in the surrounding ocean simulant. These techniques could be useful for a variety of hydrothermal microbiology simulations relevant to modern marine environments, early Earth vent environments, and putative vents on ocean worlds.