Helbig, M.

Knoblauch, C.

Kutzbach, L.

Runkle, B.

English

MPG.PuRe

Geophysical Research AbstractsVol. 16, EGU2014-8272-4, 2014EGU General Assembly 2014© Author(s) 2014. CC Attribution 3.0 License.Tracing the catchment-scale hydrology of polygonal tundra andimplications for lateral fluxes of carbon and nitrogen, Lena River Delta,SiberiaBenjamin R. K. Runkle (1), Manuel Helbig (2), Christian Knoblauch (1), and Lars Kutzbach (1)(1) Institute of Soil Science, University of Hamburg, Hamburg, Germany (benjamin.runkle@zmaw.de), (2) Department ofGeography, University of MontrealSurface-water hydrology changes the thermal regime of permafrost, carries varying amounts of nutrients de-pending on its flowpath, and provides a fuel for biogeochemical reactions, including the biological production ofmethane and carbon dioxide by soil microbes. In this work we present the findings of hydrological investigationsin the ice-wedge polygon tundra of the Samoylov Research Island in Russia’s Lena River Delta. We comparethe catchment-scale behaviour of two adjacent watersheds through stable isotope analysis conducted over twoyears of sampling (2012-13). This work also incorporates the use of conservative natural tracers such as silicaconcentration and sheds light on mechanisms for the transport of dissolved organic carbon into the Lena Riversystem.Hydrological discharge measurements taken over three years (2011-13) reveal generally similar patterns inrainfall response and permafrost thaw between two adjacent watersheds – one smaller (0.02 km2) and dominantlycomprised of the characteristic polygonal tundra and the second larger one (0.6 km2) also containing two largesurface-water reservoirs, namely a degraded ice-wedge network and a lake. However, stable isotope measurementsof hydrogen (δD) and oxygen (δ18O) reveal that the latter watershed maintains a significant surface-water isotopicsignature throughout the summer period, with greater influence of evaporation on watershed dynamics. Thesmaller, characteristic polygon catchment shows ever-increasing influence of deeper flow paths as the thaw depthincreases over the season. These small catchments release low amounts of dissolved organic carbon and nitrogenboth in terms of concentration (< 10 ppm and < 1 ppm, respectively) and as proportion of the watershed’s annualcarbon budget (< 1 % of CO2 uptake).These findings will interest permafrost researchers studying polygonal tundra, Arctic floodplains, interac-tions between the water, carbon, and energy cycles. Furthermore, modeling strategies will benefit from simplerprocess-based representations of landscape processes when upscaling to examine regional landscape-atmosphereinteractions.

Tracing the catchment-scale hydrology of polygonal tundra and implications for lateral fluxes of carbon and nitrogen, Lena River Delta, Siberia

http://hdl.handle.net/11858/00-001M-0000-0027-A903-D

Tracing the catchment-scale hydrology of polygonal tundra and implications for lateral fluxes of carbon and nitrogen, Lena River Delta, Siberia

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