Hydrology and pore water chemistry in a permafrost wetland, Ilulissat, Greenland

Jessen, Søren; Holmslykke, Hanne D.; Rasmussen, Kristine; Richardt, Niels; Holm, Peter E.

doi:10.1002/2013wr014376

Cited by 48 publications

(38 citation statements)

References 37 publications

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“…Global climate simulations suggest a widespread increase in permafrost thaw in the twenty-first century, with increased movement of water through the subsurface and, in some regions, increases in precipitation that outpace evaporation increase (Lawrence and Slater 2005). These changes in water movement through the active layer will affect weathering rates and the transport of solutes, including major cations, metals, and trace elements (Jessen et al, 2014), and inorganic and organic carbon (Schuur et al, 2015). Therefore, changes in permafrost cover and duration are likely to influence the hydrology and biogeochemical dynamics of both terrestrial and aquatic ecosystems (figure 5).…”

Section: How Are These Linkages Across the Landscape Changing?mentioning

confidence: 99%

The Arctic in the Twenty-First Century: Changing Biogeochemical Linkages across a Paraglacial Landscape of Greenland

Anderson¹,

Saros²,

Bullard³

et al. 2017

BioScience

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The Kangerlussuaq area of southwest Greenland encompasses diverse ecological, geomorphic, and climate gradients that function over a range of spatial and temporal scales. Ecosystems range from the microbial communities on the ice sheet and moisture-stressed terrestrial vegetation (and their associated herbivores) to freshwater and oligosaline lakes. These ecosystems are linked by a dynamic glacio-fluvial-aeolian geomorphic system that transports water, geological material, organic carbon and nutrients from the glacier surface to adjacent terrestrial and aquatic systems. This paraglacial system is now subject to substantial change because of rapid regional warming since 2000. Here, we describe changes in the eco- and geomorphic systems at a range of timescales and explore rapid future change in the links that integrate these systems. We highlight the importance of cross-system subsidies at the landscape scale and, importantly, how these might change in the near future as the Arctic is expected to continue to warm.

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Section: How Are These Linkages Across the Landscape Changing?mentioning

confidence: 99%

The Arctic in the Twenty-First Century: Changing Biogeochemical Linkages across a Paraglacial Landscape of Greenland

Anderson¹,

Saros²,

Bullard³

et al. 2017

BioScience

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“…Despite the frozen state of the soil there is still unfrozen pore water in permafrost soils, which is essential for microbial activity (Ershov, 1998;Jessen et al, 2014). Though microbial organisms can be active at temperatures below 0 °C, their temperature optima in arctic soils are above 0 °C (Mikan et al, 2002;Thamdrup and Fleischer, 1998).…”

Section: Nitrogen Contentsmentioning

confidence: 99%

Permafrost thaw and release of inorganic nitrogen from polygonal tundra soils in eastern Siberia

Beermann¹,

Langer

Wetterich

et al. 2016

Preprint

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Abstract. The currently observed climate warming will lead to substantial permafrost degradation and mobilization of formerly freeze-locked matter. Based on recent findings, we assume that there are substantial stocks of inorganic nitrogen (N) within the perennially frozen ground of arctic ecosystems. We studied eleven soil profiles down to one meter depth below surface at three different sites in arctic eastern Siberia, covering polygonal tundra and river floodplains, to assess the 15 amount of inorganic N stores in arctic permafrost-affected soils. Furthermore, we modeled the potential thickening of the seasonally unfrozen uppermost soil (active) layer for these sites, using the CryoGrid2 permafrost model and representation concentration pathway (RCP) 4.5 and 8.5 scenarios. The first scenario, RCP4.5, is a stabilization pathway that reaches plateau atmospheric carbon concentrations early in the 21 st century; the second, RCP8.5, is a business as usual emission scenario with increasing carbon emissions. The modeled increases in active layer thickness (ALT) were used to estimate 20 potential annual N mobilization from permafrost-affected soils in the course of climate-induced active-layer deepening. We observed significant stores of inorganic ammonium in the perennially frozen ground of all investigated soils, up to 40-fold higher than in the active layer. The modeled ALT increase until 2100 under the RCP8.5 scenario was between 19 ± 3 cm and 35 ± 6 cm, depending on the location. Under the RCP4.5 scenario, the ALT remained stable in all investigated soils. Our estimated mean annual N release under the RCP8.5 scenario is between 8 ± 3 mg m -2 and 81 ± 14 mg m -2 for the different 25 locations, which reaches values up to the order of magnitude of annual fixation of atmospheric N in arctic soils. However, the thawing induced release of N represents only a small flux in comparison with the overall ecosystem N cycling.

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“…Thus the flow velocity is variable in three dimensions: Vertical variations in the velocity are caused not only by variations in porosity and permeability over depth (Quinton et al, 2008), humification (Letts et al, 2000) and diplotelmic flow (Jessen et al, 2014) but are also related to the existence of a saturated layer at the bottom of the active layer. Lateral alterations of the velocity arise due to a network of water paths that is controlled by the micro-topography of the permafrost table (Atchley et al, 2015).…”

Section: Solute Transport In the Active Layermentioning

confidence: 99%

Water flow in the active layer along an arctic slope – An investigation based on a field campaign and model simulations

Zastruzny

Elberling

Nielsen

et al. 2017

Preprint

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Abstract. As climate conditions change, the hydrological regime in the active layer is subject to change too. This influences the transport of solutes and the availability of nutrients, e.g. nitrogen particularly, along slopes. There is a lack of understanding the pathways and travel times of water and nutrients along slopes in discontinuous permafrost regions and 10 how to scale changes along transects to the rest of the landscape. This study presents a comprehensive data set of a field site in Disko Island in Greenland aiming at constructing a hydrological model of the area. Data from automated weather stations, geophysical surveys, soil samples and soil sensors and tracer experiments are combined to describe the spatial variability in the field and to serve as input to a two-dimensional model (SUTRA) for simulating water and solute transport in the summer period. The model is calibrated and validated against volumetric water content and breakthrough curves of the applied 15 tracers. Observed and simulated results suggest that the flow velocity in the active layer is directly influenced by annual precipitation patterns leading to water flow during the summer and rapid movement at the end of summer. Yearly travel times for the specific field site are simulated to be approximately 14 m/a and the highest peak velocities are most likely caused by preferential flow paths. The spatial heterogeneities linked to the frost topography seem to control the direction and velocity of flow. The observed discontinuous movement of a conservative tracer suggests that the movement of dissolved 20 nitrogen compounds such as nitrate, being released along the slope in consequence of permafrost thawing, could possibly quickly influence nitrogen cycling at the end of the slope. This may trigger a feedback of climate changes in terms of increasing carbon sequestration due to additional plant growth in these otherwise nitrogen-limited Arctic ecosystems. 25The Cryosphere Discuss., https://doi

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Hydrology and pore water chemistry in a permafrost wetland, Ilulissat, Greenland

Cited by 48 publications

References 37 publications

The Arctic in the Twenty-First Century: Changing Biogeochemical Linkages across a Paraglacial Landscape of Greenland

The Arctic in the Twenty-First Century: Changing Biogeochemical Linkages across a Paraglacial Landscape of Greenland

Permafrost thaw and release of inorganic nitrogen from polygonal tundra soils in eastern Siberia

Water flow in the active layer along an arctic slope – An investigation based on a field campaign and model simulations

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