Pan-Arctic ice-wedge degradation in warming permafrost and its influence on tundra hydrology

Liljedahl, A. K.; Boike, Julia; Daanen, R. P.; Fedorov, A.A.; Frost, G. V.; Grosse, Guido; Hinzman, L. D.; Iijma, Yoshihiro; Jorgenson, Janet C.; Matveyeva, Nadya; Necsoiu, Marius; Raynolds, Martha K.; Romanovsky, V. E.; Schulla, J.; Tape, Ken D.; Walker, Donald A.; Wilson, Cathy J.; Yabuki, Hironori; Zona, Donatella

doi:10.1038/ngeo2674

Cited by 623 publications

(781 citation statements)

References 40 publications

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“…However, even if soil quality is optimal, moisture conditions at times of permafrost thaw crucially govern the rates of N 2 O emitted from tundra. Whether Arctic soils become wetter or drier following permafrost thaw depends largely on local hydrology and drainage conditions (27). Incorporating such postthaw landscape changes into ecosystem models still causes large uncertainties in the projections on the future C balance (9); however, it is known that even areas facing abrupt thaw and ground subsidence, initially leading to water-saturated soil conditions, often show improved drainage in the long term (27,28).…”

Section: Role Of Soil Moisture and Vegetation In Regulating Arctic N 2 Omentioning

confidence: 99%

“…Whether Arctic soils become wetter or drier following permafrost thaw depends largely on local hydrology and drainage conditions (27). Incorporating such postthaw landscape changes into ecosystem models still causes large uncertainties in the projections on the future C balance (9); however, it is known that even areas facing abrupt thaw and ground subsidence, initially leading to water-saturated soil conditions, often show improved drainage in the long term (27,28). Our findings imply that thawing of permafrost causes a considerable release of N 2 O under drier conditions when oxygen is sufficiently available for mineralization and nitrification.…”

Section: Role Of Soil Moisture and Vegetation In Regulating Arctic N 2 Omentioning

confidence: 99%

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Increased nitrous oxide emissions from Arctic peatlands after permafrost thaw

Voigt

Marushchak

Lamprecht

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

133

131

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Permafrost in the Arctic is thawing, exposing large carbon and nitrogen stocks for decomposition. Gaseous carbon release from Arctic soils due to permafrost thawing is known to be substantial, but growing evidence suggests that Arctic soils may also be relevant sources of nitrous oxide (N 2 O). Here we show that N 2 O emissions from subarctic peatlands increase as the permafrost thaws. In our study, the highest postthaw emissions occurred from bare peat surfaces, a typical landform in permafrost peatlands, where permafrost thaw caused a fivefold increase in emissions (0.56 ± 0.11 vs. 2.81 ± 0.6 mg N 2 O m −2 d −1 ). These emission rates match those from tropical forest soils, the world's largest natural terrestrial N 2 O source. The presence of vegetation, known to limit N 2 O emissions in tundra, did decrease (by ∼90%) but did not prevent thaw-induced N 2 O release, whereas waterlogged conditions suppressed the emissions. We show that regions with high probability for N 2 O emissions cover one-fourth of the Arctic. Our results imply that the Arctic N 2 O budget will depend strongly on moisture changes, and that a gradual deepening of the active layer will create a strong noncarbon climate change feedback.

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Section: Role Of Soil Moisture and Vegetation In Regulating Arctic N 2 Omentioning

confidence: 99%

Section: Role Of Soil Moisture and Vegetation In Regulating Arctic N 2 Omentioning

confidence: 99%

Increased nitrous oxide emissions from Arctic peatlands after permafrost thaw

Voigt

Marushchak

Lamprecht

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

133

131

View full text Add to dashboard Cite

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“…Geomorphological processes such as subsidence (Jorgenson et al, 2006;O'Donnell et al, 2012) as well as the formation of a system of connected troughs through the preferential degradation of ice wedges in ice-rich permafrost (Serreze et al, 2000;Liljedahl et al, 2016) can lead to a lateral redistribution of water, and thus can create both wetter and drier microsites within a formerly uniform ecosystem. Also, a deepening of the active layer can trigger reductions in waterlogged conditions and wetland extent in permafrost regions (Avis et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Shifted energy fluxes, increased Bowen ratios, and reduced thaw depths linked with drainage-induced changes in permafrost ecosystem structure

et al. 2017

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Abstract. Hydrologic conditions are a key factor in Arctic ecosystems, with strong influences on ecosystem structure and related effects on biogeophysical and biogeochemical processes. With systematic changes in water availability expected for large parts of the northern high-latitude region in the coming centuries, knowledge on shifts in ecosystem functionality triggered by altered water levels is crucial for reducing uncertainties in climate change predictions. Here, we present findings from paired ecosystem observations in northeast Siberia comprising a drained and a control site. At the drainage site, the water table has been artificially lowered by up to 30 cm in summer for more than a decade. This sustained primary disturbance in hydrologic conditions has triggered a suite of secondary shifts in ecosystem properties, including vegetation community structure, snow cover dynamics, and radiation budget, all of which influence the net effects of drainage. Reduced thermal conductivity in dry organic soils was identified as the dominating drainage effect on energy budget and soil thermal regime. Through this effect, reduced heat transfer into deeper soil layers leads to shallower thaw depths, initially leading to a stabilization of organic permafrost soils, while the long-term effects on permafrost temperature trends still need to be assessed. At the same time, more energy is transferred back into the atmosphere as sensible heat in the drained area, which may trigger a warming of the lower atmospheric surface layer.

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“…This information is vital to practical engineering for commerce and industry activity as well to support science objectives in Biology and Ecology, Geology and Geophysics, Hydrology and Meteorology. Knowledge of current ice-wedge networks, both high and low-center polygons and their changes over multi-year to decadal time and effects from temporary human habitation is vital [35]. We must measure millimeter level changes at sufficient accuracy and precision to improve estimates of the changes in carbon storage that portend large positive feedback to the Earth's climate system and land vegetation on decadal to centennial time scales and can adversely affect the stability of the Earth's permafrost periglacial regions [36] [37].…”

Section: Discussionmentioning

confidence: 99%

L-Band InSAR Penetration Depth Experiment, North Slope Alaska

Muskett¹

2017

GEP

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Since the first spacecraft-based synthetic aperture radar (SAR) mission NASA's SEASAT in 1978 radars have been flown in Low Earth Orbit (LEO) by other national space agencies including the Canadian Space Agency, European Space Agency, India Space Research Organization and the Japanese Aerospace Exploration Agency. Improvements in electronics, miniaturization and production have allowed for the deployment of SAR systems on aircraft for usage in agriculture, hazards assessment, land-use management and planning, meteorology, oceanography and surveillance. LEO SAR systems still provide a range of needful and timely information on large and small-scale weather conditions like those found across the Arctic where ground-base weather radars currently provide limited coverage. For investigators of solidearth deformation attention must be given to the atmosphere on Interferometric SAR (InSAR) by aircraft and spacecraft multi-pass operations. Because radar has the capability to penetrate earth materials at frequencies from the Pto X-band attention must be given to the frequency dependent penetration depth and volume scattering. This is the focus of our new research project: to test the penetration depth of L-band SAR/InSAR by aircraft and spacecraft systems at a test site in Arctic Alaska using multi-frequency analysis and progressive burial of radar mesh-reflectors at measured depths below tundra while monitoring environmental conditions. Knowledge of the L-band penetration depth on lowland Arctic tundra is necessary to constrain analysis of carbon mass balance and hazardous conditions arising from permafrost degradation and thaw, surface heave and subsidence and thermokarst formation at local and regional scales.

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Pan-Arctic ice-wedge degradation in warming permafrost and its influence on tundra hydrology

Cited by 623 publications

References 40 publications

Increased nitrous oxide emissions from Arctic peatlands after permafrost thaw

Increased nitrous oxide emissions from Arctic peatlands after permafrost thaw

Shifted energy fluxes, increased Bowen ratios, and reduced thaw depths linked with drainage-induced changes in permafrost ecosystem structure

L-Band InSAR Penetration Depth Experiment, North Slope Alaska

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