Correlation between microbiological and chemical parameters of some hydrothermal springs in New Mexico, USA

Discharge areas of hydrothermal springs are known to be inhabited by diverse types of microorganisms including archaea, prokaryotes and eukaryotes. A total of I I hydrothermal samples from the Rio Grande rift and the Valles caldera in New Mexico were analyzed to investigate the correlation between chemical and microbiological parameters of hydrothermal waters. The sampled fluids are categorized into three chemical groups: (1) steam-condensing acid sulfate waters, (H) deep geothermal and derivative waters and (111) thermal meteoric waters. Analyses of the microbial phospholipid fatty acids and denaturing gradient gel electrophoresis of DNA show that acid sulfate waters were populated by thermoacidophilic organisms and had high biomass content. Mineralized deep geothermal and derivative waters exhibited a high degree of microbial diversity, but had low biomass content. Thermal meteoric waters are low in total dissolved solids, and exhibit very low biomass content and microbial diversity. DNA sequences from several previously unknown microbial species were detected. The results of this study support the hypothesis that microbes can be used as tracers for specific types of subsurface environments. (C) 2003 Elsevier B.V. All rights reserved.