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

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 CO2 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 (2017_Werenskioldbreen_catchment_sediment_bound_and_dissolved_Fe_P_Si_v1.csv), physiochemical properties of water (2017_Werenskioldbreen_catchment_physiochemical_measurements_v1.csv), and major ions chemistry (2017_Werenskioldbreen_catchment_water_chemistry_v1.csv)

Keywords

meltwater, silica, iron, phosphorous, Arctic, glacier, suspended sediments

Acknowledgement

This study is a contribution to the National Science Centre project FLOURISH (SONATA funding scheme, award No. 2021/43/D/ST10/00687) and RAW (GRIEG-1 funding scheme, award No. 2019/34/H/ST10/00504). ŁS was supported from the Bekker Programme (award no. BPN/BEK/2021/1/00431) at the Polish National Agency for Scientific Exchange. For the purpose of Open Access, the author has applied a CC BY public copyright licence to any Author Accepted Manuscript (AAM) version arising from this submission. This project has received funding from the European Union’s Horizon 2020 research and innovation Transnational Access programme “Electron and X-ray microscopy Community for structural and chemical Imaging Techniques for Earth materials (EXCITE) ” under grant agreement No 101005611. ŁS and MDS acknowledge funding for their transnational Access (TNA id: EXCITE_TNA_C2_2022_008) for research conducted at the Potsdam Imaging and Spectral Analyses (PISA) facility at the Helmholtz-Zentrum Potsdam Deutsches GeoforschungsZentrum (GFZ). The study was carried out as part of scientific activity of the Centre for Polar Studies (University of Silesia in Katowice) with the use of research and logistic equipment (monitoring and measuring equipment, sensors, multiple AWS, GNSS receivers, snowmobiles and other supporting equipment) of the Polar Laboratory of the University of Silesia in Katowice.