Microbial Observatories: Linking Microbial Community Structure and Function in Contaminated Aquifers

University Of California-Davis, Davis CA

Investigators

Abstract

A grant has been awarded to Drs. Kate Scow and Krassi Hristova of the University of California at Davis to study the diversity of microbial communities in uncontaminated and contaminated shallow groundwater aquifers. Groundwater communities are surprisingly diverse, both taxonomically and functionally, and reflect the considerable heterogeneity in geology, hydrology, and geochemistry found below the surface. Aquifers are sources of a major portion of the US drinking water supplies and aquifers directly connect with surface water environments. Many aquifers in urban and agricultural areas are polluted with organic and inorganic contaminants; their potential for recovery in part depends on the diversity of its microbial communities. The objectives of this study are to characterize community and discover new organisms in shallow groundwater aquifers, measure how petroleum contamination (including the fuel additive methyl tertiary butyl ether-MTBE) changes microbial diversity, and link community composition with environmental factors and process rates. Approaches used will include traditional culture-based methods, DNA fingerprinting coupled with cloning and sequencing, lipid analysis and measurements of process rates. Groundwater aquifers are important microbial habitats with potentially large impacts on society and the environment; understanding of the microbial ecology and diversity of these environments lags far behind that of soil and aquatic ecosystems. From an evolutionary perspective, contaminated aquifers are relatively new ecosystems and thus provide opportunities to study microbial adaptation. In addition to discovering new microbial diversity in shallow groundwater aquifers, other contributions of this study will include measuring how diversity of microbial communities responds to contamination and developing tools for linking ecosystem processes to specific groups of microorganisms. This knowledge has broader significance because many of the earth's ecosystems are perturbed by human activities. Understanding microbial adaptation to contaminants and other stresses will help in the rehabilitation and restoration of damaged ecosystems.