| Abstract: | Recent models of chemical weathering in alpine glacial meltwaters suggest that sulphide oxidation is a major source of solute in the distributed component of the subglacial hydrological system. This reaction requires O2, and may lower dissolved oxygen levels to below saturation with respect to the atmosphere. This should result in an inverse association between SO72- and dissolved oxygen saturation. However, measurements of O2 saturation in bulk meltwaters draining the Haut Glacier d'Arolla, Switzerland, show that there is a positive association between SO42- and O2 saturation. The O2 content of glacial meltwaters depends on the initial content of snow and icemelt, which may be controlled by the rate of melting, and the kinetic balance between O2 losses (e.g. sulphide oxidation, microbial respiration) and gains (e.g. diffusion of O2 into solution). |
