Peatland Hydrology of Discontinuous Permafrost in the Northwest Territories: Overview and Synthesis

Quinton, William L.; Hayashi, Masaki; Chasmer, L.

doi:10.4296/cwrj3404311

Cited by 102 publications

(142 citation statements)

References 21 publications

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“…Soil temperature was not a statistically significant estimate for any of the thaw stages. Elevation was significant for thaw stages 1, 4, 8 and 9; thaw depth for 1,4,5,7,8 and 10;and VGA for 8 and 9. larger effect of thaw depth in these stages .The larger variance in thaw depth could be attributed to a steeper drop in thaw depths as the growing season progresses in the wetter thaw stages due to the dependence of thermal conductivity of peat on the degree of wetness (Quinton et al, 2009). While bivariate relationships between correlates and C flux provide insight into the possible controls on these fluxes, multiple regressions better demonstrate the interactive nature of these correlates.…”

Section: Trends With Increasing Thawmentioning

confidence: 99%

“…Initial ground subsidence from thaw results in wet habitats due to a high water table (Smith et al, 2012). Relative to dry areas, the seasonal frost table thaws faster in wet areas, further increasing lateral flow of water to wet areas (Quinton et al, 2009). The increase in water table depth (WTD) leads to a vegetation shift toward wetter communities and an increase in graminoid species (Camill, 1999;Camill et al, 2001;Malmer et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

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Environmental correlates of peatland carbon fluxes in a thawing landscape: do transitional thaw stages matter?

Malhotra

Roulet

2015

Biogeosciences

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Abstract. Peatlands in discontinuous permafrost regions occur as a mosaic of wetland types, each with variable sensitivity to climate change. Permafrost thaw further increases the spatial heterogeneity in ecosystem structure and function in peatlands. Carbon (C) fluxes are well characterized in endmember thaw stages such as fully intact or fully thawed permafrost but remain unconstrained for transitional stages that cover a significant area of thawing peatlands. Furthermore, changes in the environmental correlates of C fluxes, due to thaw, are not well described -a requirement for modeling future changes to C storage of permafrost peatlands. We investigated C fluxes and their correlates in end-member and a number of transitional thaw stages in a sub-arctic peatland. Across peatland-lumped CH 4 and CO 2 flux data had significant correlations with expected correlates such as water table depth, thaw depth, temperature, photosynthetically active radiation and vascular green area. Within individual thaw states, bivariate correlations as well as multiple regressions between C flux and environmental factors changed variably with increasing thaw. The variability in directions and magnitudes of correlates reflects the range of structural conditions that could be present along a thaw gradient. These structural changes correspond to changes in C flux controls, such as temperature and moisture, and their interactions. Temperature sensitivity of CH 4 increased with increasing thaw in bivariate analyses, but lack of this trend in multiple regression analyses suggested cofounding effects of substrate or water limitation on the apparent temperature sensitivity. Our results emphasize the importance of incorporating transitional stages of thaw in landscape level C budgets and highlight that end-member or adjacent thaw stages do not adequately describe the variability in structure-function relationships present along a thaw gradient.

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Section: Trends With Increasing Thawmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Environmental correlates of peatland carbon fluxes in a thawing landscape: do transitional thaw stages matter?

Malhotra

Roulet

2015

Biogeosciences

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“…For example, near-surface water tables in fall of 2012 and 2013 (Fig. 5) allowed for relatively homogenous overwinter freezing of the upper saturated zone (Price, 1983), which reduced the permeability of the peat (Roulet and Woo, 1986;Quinton et al, 2009) and helped store subsurface water over the winter periods (Price and FitzGibbon, 1987). Ground ice persisted into mid-late May in 2013 and 2014, thus limiting snowmelt water infiltration (Roulet and Woo, 1986) and subsurface water loss to the underlying silty sand and outwash layers (Price and FitzGibbon, 1987).…”

Section: Pre-fire Hydrologymentioning

confidence: 99%

Hydrometeorological conditions preceding wildfire, and the subsequent burning of a fen watershed in Fort McMurray, Alberta, Canada

Elmes

Thompson

Sherwood

et al. 2018

Nat. Hazards Earth Syst. Sci.

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Abstract. The destructive nature of the ∼ 590 000 ha Horse river wildfire in the Western Boreal Plain (WBP), northern Alberta, in May of 2016 motivated the investigation of the hydrometeorological conditions that preceded the fire. Historical climate and field hydrometeorological data from a moderate-rich fen watershed were used to (a) identify whether the spring 2016 conditions were outside the range of natural variability for WBP climate cycles, (b) explain the observed patterns in burn severity across the watershed, and (c) identify whether fall and winter moisture signals observed in peatlands and lowland forests in the region are indicative of wildfire. Field hydrometeorological data from the fen watershed confirmed the presence of cumulative moisture deficits prior to the fire. Hydrogeological investigations highlighted the susceptibility of fen and upland areas to water table and soil moisture decline over rain-free periods (including winter), due to the watershed's reliance on supply from localized flow systems originating in topographic highs. Subtle changes in topographic position led to large changes in groundwater connectivity, leading to greater organic soil consumption by fire in wetland margins and at high elevations. The 2016 spring moisture conditions measured prior to the ignition of the fen watershed were not illustrated well by the Drought Code (DC) when standard overwintering procedures were applied. However, close agreement was found when default assumptions were replaced with measured duff soil moisture recharge and incorporated into the overwintering DC procedure. We conclude that accumulated moisture deficits dating back to the summer of 2015 led to the dry conditions that preceded the fire. The infrequent coinciding of several hydrometeorological conditions, including low autumn soil moisture, a modest snowpack, lack of spring precipitation, and high spring air temperatures and winds, ultimately led to the Horse river wildfire spreading widely and causing the observed burn patterns. Monitoring soil moisture at different land classes and watersheds would aid management strategies in the production of more accurate overwintered DC calculations, providing fire management agencies early warning signals ahead of severe spring wildfire seasons.

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“…The trees become waterlogged and die, and collapse scars are vegetated by hydrophilic taxa such as sedges and mosses (Beilman et al 2001). Because peat plateaus act as barriers to the lateral flow of water, redirecting surface and subsurface flow into channel fens, the loss of permafrost peat plateaus leads to substantial hydrological changes (Quinton et al 2009). Peat subsidence and the loss of permafrost plateaus generally promote increased connectivity of drainage networks and export of DOC to aquatic ecosystems (Quinton et al 2009;Olefeldt and Roulet 2014).…”

Section: South Slave Taiga Plains Northwest Territoriesmentioning

confidence: 99%

Paleolimnology of thermokarst lakes: a window into permafrost landscape evolution

et al. 2017

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Widespread across northern permafrost landscapes, thermokarst ponds and lakes provide vital wildlife habitat and play a key role in biogeochemical processes. Stored in the sediments of these typically shallow and dynamic waterbodies are rich sources of paleoenvironmental information whose potential has not yet been fully exploited, likely because of concerns over stratigraphic preservation and challenges to develop reliable sediment core chronologies. Here, we present an overview of recently derived informative paleolimnological reconstructions based on multiparameter analysis of sediment archives from permafrost aquatic basins. We include examples from across the Canadian North, Alaska, and Siberia that illustrate their value for providing insights into temporal patterns of lake inception, catchment erosion, aquatic productivity, hydrological evolution, and landscape disturbances. Although not captured in our survey, emerging research directions focused on carbon accumulation, storage, and balance hold much promise for contributing to global climate change science.Key words: thermokarst lakes, permafrost, paleolimnology, lake sediments.Résumé : Répandus d'un paysage de pergélisol septentrional à l'autre, les étangs et les lacs thermokarstiques fournissent un habitat essentiel à la faune et jouent un rôle clé dans les processus biogéochimiques. Accumulées dans les sédiments de ces plans d'eau typiquement peu profonds et dynamiques se trouvent des sources riches en informations paléoenvironne-mentales dont le potentiel n'a pas encore été entièrement exploité, probablement à cause des préoccupations concernant la conservation stratigraphique et les défis de développer des chronologies fiables à partir des carottes sédimentaires. Ici, nous présentons une vue d'ensemble des reconstitutions paléolimnologiques informatives récemment dérivées d'après l'analyse multi paramétrée d'archives de sédiments des bassins aquatiques du pergé-lisol. Nous incluons des exemples provenant du Nord canadien, de l'Alaska et de la Sibérie qui For personal use only.illustrent que ceux-ci peuvent offrir des perspectives sur les tendances temporelles de création de lacs, de l'érosion de bassins versants, de la productivité aquatique, de l'évolution hydrologique et des perturbations du paysage. Bien que non mises en lumière dans notre enquête, les directions de recherche émergentes centrées sur l'accumulation, le stockage et le bilan carbone s'annoncent bien quant à leur contribution à la science du changement climatique mondial.

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Peatland Hydrology of Discontinuous Permafrost in the Northwest Territories: Overview and Synthesis

Cited by 102 publications

References 21 publications

Environmental correlates of peatland carbon fluxes in a thawing landscape: do transitional thaw stages matter?

Environmental correlates of peatland carbon fluxes in a thawing landscape: do transitional thaw stages matter?

Hydrometeorological conditions preceding wildfire, and the subsequent burning of a fen watershed in Fort McMurray, Alberta, Canada

Paleolimnology of thermokarst lakes: a window into permafrost landscape evolution

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