MOUNT RAINIER GLACIAL MELTWATER HYDROCHEMISTRY AND MICROBIAL COMMUNITIES

Mount Rainier is a geothermally active, glaciated peak. In this study, we analyze glacial meltwater hydrochemistry and microbial life as one way to characterize subglacial environments. We measure major ion concentrations in meltwater samples collected from streams at or near glacier termini in Mount Rainier National Park. Preliminary data show constant sulfate levels during the diurnal cycle, and low C-ratios (bicarbonate/[bicarbonate + sulfate]) at Tahoma and Emmons Glaciers, suggesting a subglacial source of sulfate at both locations. Carbon Glacier meltwater contains relatively low levels of sulfate, with a significant decrease between the diurnal maximum and minimum and a high C-ratio, indicating a supraglacial source of sulfate. Tentative conclusions include that Tahoma Glacier meltwater is in contact with the mountain’s hydrothermal system; this result confirms findings from previous work. Our work also suggests a subglacial source of sulfate at the Emmons Glacier; if confirmed, this result may identify a connection between the subglacial environment and the hydrothermal system. Since microbes are reliant on the chemistry of the water in which they reside, it is likely that a link between hydrochemistry, geothermal activity, and microbial life exists. Thus, we also use sequenced DNA of microbes found in glacial meltwater to provide additional insight into these complex environments.