Investigation of hydrothermal sources in the Rio Grande rift region
— Bartlomiej Rzonca and Dirk Schulze-Makuch

Hydrothermal water samples were obtained from 11 locations associated with the Rio Grande Rift and analyzed for chemical and microbial composition. The sampled hydrothermal waters can be categorized into three groups of water: (I) steam condensing, sulfur-rich acidic water, (II) mixtures of deep thermal water with shallow groundwater and (III) heated meteoric water, Category I water was populated by thermoacidophilic organisms with a high biomass content, while category II water was highly mineralized and indicating a high degree of microbial diversity but low biomass content. Heated meteoric water (category III) was low in biomass content and microbial diversity. We conclude that microbes can be used as tracer for specific types of subsurface environments and aim further studies to reveal which hydrothermal upflow regions are related to each other using microbial, chemical and isotope analyses.