MEASURING CARBON FLUX IN ICELANDIC GLACIAL RIVERS UNDER A CHANGING CLIMATE

Temperate glaciers of Iceland are dynamic systems vulnerable to changes in climate. The release of carbon dioxide (CO₂), a greenhouse gas, is a part of the normal lifecycle of a glacier, but is exacerbated by various influences, including increases in air temperature. Various sources, dominant and minor, of CO₂ transported within glacial-fed streams are both stored and transported during glacial melting events. The glaciers release trapped atmospheric CO₂ as they melt, but also consume CO₂ from sub-glacial weathering processes occurring between the basaltic bedrock and sub-glacial streams, as well as during the surface stream weathering process. Here, we present a longitudinal study of three glacial streams to quantify and characterize the carbon flux in streams from three glaciers in Iceland: Gígjökull, Steinholtsjökull, and Sólheimajökull. Hydrogeochemical parameters including pH, specific conductivity, temperature, and DO were collected at each sample site. Samples for alkalinity, to determine the bicarbonate alkalinity of the water, anions, cations, and stable carbon isotopes were collected and discharge was determined using an acoustic doppler current profiler for the glacier outlet rivers. Isotope data were processed to identify the separate sources of the inorganic carbon within the system. Preliminary data indicate the hydrochemistry of the water changes longitudinally and varies by site; site-specific parameters, such as various tributary influences, lithology of the bedrock, and stream inputs. Glacial surface stream inputs were distinct from sub-surface streams as indicated by colder temperatures, lower specific conductivity, and changes in pH and alkalinity. Completion of this study will contribute quantified data to the current body of carbon flux and better characterize the influences of climate change in vulnerable Arctic environments.