Biogeochemical processes have a major impact on water quality and the management of water resources, through the important role they play in a number of subsurface environments—ranging from soils and shallow sediments, to drinking water aquifers, to deep gas or oil reservoirs. Biogeochemical processes are also the key element in the natural attenuation of contaminants, and are now being manipulated in various bioremediation schemes intended to accelerate contaminant cleanup. However, our understanding of the functioning of microbially mediated biogeochemical processes in the subsurface is still inadequate. While this results in part from the need for additional fundamental research, it also reflects the need for a new generation of fully coupled biogeochemical transport models that can capture quantitatively the complex interactions between the subsurface environment and the resident biota, across a wide range of scales.

This session will focus on innovative approaches to modeling subsurface biogeochemical processes. Topics to be considered include interactions among subsurface transport, biogeochemistry, and microbial processes across multiple scales, the representation of microbial processes and the biosphere in reactive transport models, bioenergetic constraints on microbially mediated processes, element and nutrient cycling as a result of biogeochemical processes in soils and shallow sediments, and the incorporation of isotope systematics into biogeochemical models to improve the constraints on reaction networks and rates.