Exploring the Extreme Conditions Underwhich Life Thrives, Survives and Expires
Volcanic systems and microorganisms on Earth have co-evolved for nearly 4 billion years.
The connection between volcanism and life perhaps is nowhere more evident than at mid-ocean ridge spreading centers. The range and complexity of the physical and chemical gradients awaiting detailed study in submarine hydrothermal vents encompass the extreme conditions that generally support only such microorganisms as hyperthermophilic Archaea. These conditions include high temperatures, high hydrostatic pressures, extreme salinity gradients, low concentrations of carbon compounds, and limited kinds of electron acceptors and donors. To examine the in situ conditions under which organisms thrive, survive, and expire in high temperature hydrothermal vent environments, we have developed a multi-chambered microbial incubator designed to go inside the walls of black smoker chimneys. Each instrument houses 304 discrete chambers with up to 36 temperature sensors distributed along the axis of the incubator, and up to two osmo samplers that allow for coregistered fluid sampling. The incubators have been successfully deployed for two to 1-year periods: redepoyments in the same experimental drill hole allow examination of the temporal evolution of microbial communities in the context of both temperature and fluid chemistry.