7.5 - Geochemical Weathering in Glacial and Proglacial Environments

Abstract

Chemical weathering in glacial environments is a hot topic because physical and microbially mediated processes help produce bioavailable nutrients, including P and Fe, that can be readily used by organisms in downstream environments. Additionally, glacial processes provide rock-derived energy sources and nutrients to subglacial aquatic environments that are colonized by microbes. Eh–pH changes across the spectrum of subglacial aquatic environments means that there is a diverse spectrum of aerobic and anaerobic habitats for microbes to colonize, and hence a diverse spectrum of microbes are found, and are likely to be found in future, beneath glaciers and ice sheets. Sulfide oxidation is a key reaction under smaller glaciers, and it is likely that sulfate reduction and methanogenesis are important reactions in soil, marine and lacustrine sediments overridden by ice sheets. This chapter summarizes the current literature on these topical issues.