Controls of sediment-bound and dissolved nutrient transport from a glaciated metasedimentary catchment in the high Arctic

• Main Authors: Stachnik, Lukasz, Hawkings, Jon, Spolaor, Andrea, Stachniak, Katarzyna, Ignatiuk, Dariusz, Sitek, Sławomir, Janik, Krzysztof, Łepkowska, Elżbieta, Burgay, Francois, Syczewski, Marcin Daniel, Segato, Delia
• Format: Other/Unknown Material
• Language: English
• Published: Zenodo 2024
• Subjects: meltwater; silica; iron; phosphorous; Arctic; glacier; suspended sediments; Greenland; Ice Sheet; Spitsbergen
• Online Access: https://doi.org/10.5281/zenodo.10650475

Abstract Rapid warming in polar and alpine areas is causing significant glacier mass loss and resulting in increasingly large quantities of freshwater delivery to the oceans. Recent research indicates that higher meltwater water runoff is likely to increase transport of solute and sediments, which will include nutrients, to downstream environments. This enhanced delivery may drive a negative feedback effect on atmospheric CO 2 concentrations by fuelling primary production in fjords and near-coastal regions. Labile sediment-bound fractions constitute a high proportion of the total nutrient yield from a glacierised basin but data is sparse and the impact of these particulate nutrients is debated. Here we determine sediment-bound and dissolved nutrient (Si, Fe, P) delivery from a polythermal glacier in SW Spitsbergen. Suspended sediment and dissolved samples were collected from subglacial outflows, and a downstream site. Our results show high spatial variability of chemical weathering processes resulting in differences in sediment-bound nutrient concentration. There is variation between sulphide oxidation and carbonation dissolution in channelized systems, and silicate weathering in minor subglacial outflows with short residence time. The former channelized systems have two times higher content of sediment-bound iron (0.29 % d.w.) than the latter minor outflows. In contrast, sediment-bound amorphous silica is higher for the minor outflows (0.17 % d.w. vs 0.10 % d.w.). The yield of sediment-bound nutrients Fe and Si (2.3 and 1.3 Mg km -2 yr -1 , respectively) was several times higher than the dissolved flux of those elements. Sediment-bound iron yields were in the range of values noted for the Greenland Ice Sheet. Our data shows the critical role of sediment-bound nutrients on nutrient cycling in glacierised basins of the high Arctic. Database consists of following data obtained from ablation season 2017: discharge data from ( 2017_Breelva_River_Discharge_v1.csv ), sediment-bound and dissolved nutrients ( ...