Chapter 12 - Field Observations, Experimental Studies, and Thermodynamic Modeling of CO2 Effects on Microbial Populations

Abstract

Microorganisms catalyze carbon cycling and biogeochemical reactions in the deep subsurface, generating biomass and extracellular materials. Following geologic carbon dioxide sequestration (GCS), subsurface microorganisms may influence the fate of injected supercritical (sc) CO2, as well as mediate secondary reactions relevant to mineralization and ground water quality. This chapter will review the current state of knowledge concerning the microbiology of GCS including the potential effects of injected scCO2 on subsurface microbial cells, populations, and communities, and microbiological feedbacks relevant to the evolution of brine chemistry, mineral surfaces, and changes in porosity. Recent work including thermodynamic modeling, field observations of CO2 injection, observations from natural analog sites, and laboratory model systems, shed light on the microbial populations and biogeochemical transformations expected after GCS. Modern molecular and genomics tools have revealed potential physiological and metabolic strategies for microbial community function under conditions associated with GCS. These studies advance our understanding of microbial processes during GCS and enable further development of bio-based interventions that may help to de-risk and optimize implementation of GCS at large scale.