Fluorescence properties of dissolved organic matter from Leverett Glacier outflow

• Main Authors: Kellerman, Anne M, Hawkings, Jon R, Wadham, Jemma, Kohler, Tyler, Stibal, Marek, Grater, Elizabeth, Marshall, Matthew, Hatton, Jade Elizabeth, Beaton, Alexander, Spencer, Robert G M
• Format: Dataset
• Language: English
• Published: PANGAEA 2020
• Subjects: Campbell Scientific 247-L Conductivity and Temperature Probe; Carbon; organic; dissolved; dissolved load; Conductivity; DATE/TIME; Day of the year; Dissolved Organic Matter; DOM; Event label; Flow rate; Fluorescence; at 317 nm wavelength; at 368 nm wavelength; at 416 nm wavelength; at 425 nm wavelength; at 483 nm wavelength; Fluorescence spectrometer; AquaLog; HORIBA JobinYvon; Glaciers; Greenland; Honeywell Durafet pH sensors; Lachat QuickChem 8500 flow injection autoanalyser; L Atalante; Leverett_glacier_basal_ice; Leverett_glacier_snow; Leverett_glacier_time_series; Nitrogen in nitrate; PARAFAC; Period; pH; Phosphorus in orthophosphate; Pressure transducer; HOBO; Roorkee Industries Suspended Sediment Sampler USDH-48; SNOW; Arctic; glacier; Ice Sheet; Leverett Glacier
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.910920; https://doi.org/10.1594/PANGAEA.910920

The outflow of Leverett Glacier, a large land-terminating glacier of the Greenland Ice Sheet was sampled over the 2015 ablation season. Dissolved organic carbon (DOC) concentrations, dissolved organic matter (DOM) fluorescence, and hydrogeochemical data (e.g. discharge, specific conductivity, pH, and turbidity) were analyzed to assess changing DOM sources over the melt season. DOC concentrations and red-shifted fluorescence suggest terrestrial inputs from overridden soils dominated DOM early season inputs before progressive dilution with increasing discharge. During the outburst period, supraglacial drainage events disrupted the subglacial drainage system and introduced dominant protein-like fluorescence signatures not observed in basal flow. These results suggest that subglacial hydrology and changing water sources influence exported DOC concentration and DOM composition, differentiated through fluorescence characteristics. The outburst and post-outburst periods were characterized by protein-like fluorescence from supraglacial and potentially subglacial microbial sources.