ABSTRACT
This chapter explores how glacial meltwaters acquire solute, how this evolves as meltwaters travel through the glacial environment and investigates the impact of the exported meltwaters on local and global biogeochemical processes downstream. Exported in these meltwaters is a distinct array of dissolved and particulate material evacuated from glacial environments. Glaciers which are entirely frozen to their beds experience very limited chemical weathering, since little meltwater reaches the ice-bed interface. Meltwater generated at the glacier surface flows down through the ice to discharge into the proglacial environment. Modelling studies have been undertaken to understand the impact of export of nutrients from glacial environments on local, regional and global biogeochemical cycles. The presence of active populations of microorganisms in glacial environments has profound impacts on the composition of runoff. Evidence for methane cycling beneath the Antarctic and Greenland ice sheets shows that microorganisms can degrade organic carbon even under anoxic conditions.
