Chapter 2 - The microbiology of natural analogue sites

Abstract

A geological disposal facility (GDF) will be an extreme environment for microorganisms and will likely restrict their growth and metabolism. Lower metabolic activities in GDF-relevant conditions are challenging to quantify in the laboratory, where experiments are time constrained, and similarly difficult to quantify in situ, in the limited number of underground laboratories available for study. However, drawing parallels with the natural environment allows understanding of the metabolic capabilities and adaptations of microorganisms over a longer timescale. Environments that possess similar characteristics to those anticipated in a GDF are termed natural analogues. As no true, complete analogue exists, natural analogues usually only represent one aspect of a GDF (e.g., radionuclide immobilization). Although microbiological studies have been overlooked during natural analogue investigations, those studies that have a microbial component reflect the persistence and adaptability of microorganisms, as well as their ability to interact with and alter their environment. Natural analogues may provide insights into the role that microorganisms may play in the long-term safe disposal of radioactive waste.