Water extracts from Siberian thawing permafrost - from land to ocean

• Main Authors: Schirrmeister, Lutz, Siegert, Christine, Eulenburg, Antje, Overduin, Paul, Schwamborn, Georg, Fuchs, Matthias, Fritz, Michael, Ogneva, Olga, Strauss, Jens, Grosse, Guido
• Format: Conference Object
• Language: unknown
• Published: 2023
• Subjects: Arctic; Arctic Ocean; Laptev Sea; Ice; laptev; permafrost; Siberia
• Online Access: https://epic.awi.de/id/eprint/57865/; https://epic.awi.de/id/eprint/57865/1/Poster%20water%20extracts.pdf; https://hdl.handle.net/10013/epic.248676c8-78f5-4989-bbb0-0f88daa9f815

To better understand and quantify fluxes of dissolved elements upon permafrost thaw, water-soluble elements from Siberian permafrost samples covering a wide geographic range were determined by extraction. We measured the pH- and EC-values as well as the total dissolved major and secondary cation concentrations and anion concentrations for 270 water extracts from 12 different sites around the Laptev Sea. Cation concentrations were analyzed using inductively coupled plasma-optical emission spectrometry and anion concentrations by ion chromatography. Hydrogen carbonate concentrations were measured by potentiometric pH-value titration using an automatic titrator. Electrical conductivity and pH values were measured using a WTW MultiLab 540 multi-parameter device. As ground ice melts throughout Siberia with continued climate warming, drainage of the soils in many locations is improving and exposing mineral surfaces that were previously largely inert by their perennially frozen condition and unaffected by active weathering through seasonal wetting and drying cycles. Chemical analyses of water extracts allow an assessment of the potential interactions between mineral surfaces and pore melt water and the characteristics and biogeochemical and ecological consequences of the export of melt water from thawing permafrost. The (hydro-)chemical flux from permafrost sources into the riverine and marine realms is mainly defined by its source signatures and concentrations, which will be addressed in the present study. We compare our values with water data from lakes, rivers and the Arctic Ocean. The influence of terrestrial input from thawing permafrost including ground ice is expected to increase as coastal and river shore erosion as well as other permafrost degradation processes accelerate under Arctic warming and mobilize previously freeze-locked material. The increasing influx of dissolved elements influences transport and deposition processes in aquatic environments as well as nutrient supply, food chains and life cycles ...