The influence of thermokarst disturbance on the water quality of small upland lakes, Mackenzie Delta region, Northwest Territories, Canada

Kokelj, Steven V.; Jenkins, R.E.; Milburn, David; Burn, C. R.; Snow, N.

doi:10.1002/ppp.536

Cited by 135 publications

(178 citation statements)

References 25 publications

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“…Such effects are also likely in thermokarst lakes, but have received little attention to date. Thermokarst processes result in inputs of eroded permafrost material into these water bodies, including POC (particulate organic carbon) and DOC, nutrients, and ions (Mackenzie Delta uplands, Kokelj et al, 2005;circum-Arctic, Prowse et al, 2006;Alaska, Bowden et al, 2008), which are further concentrated with the lake freeze-up during winter (Canadian Arctic, Grasby et al, 2013;Canadian sub-Arctic, Deshpande et al, 2015), in turn affecting water column stability. The hydrodynamic effects…”

Section: 2)mentioning

confidence: 99%

Reviews and syntheses: Effects of permafrost thaw on Arctic aquatic ecosystems

et al. 2015

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Abstract. The Arctic is a water-rich region, with freshwater systems covering about 16 % of the northern permafrost landscape. Permafrost thaw creates new freshwater ecosystems, while at the same time modifying the existing lakes, streams, and rivers that are impacted by thaw. Here, we describe the current state of knowledge regarding how permafrost thaw affects lentic (still) and lotic (moving) systems, exploring the effects of both thermokarst (thawing and collapse of ice-rich permafrost) and deepening of the active layer (the surface soil layer that thaws and refreezes each year). Within thermokarst, we further differentiate between the effects of thermokarst in lowland areas vs. that on hillslopes. For almost all of the processes that we explore, the effects of thaw vary regionally, and between lake and stream systems. Much of this regional variation is caused by differences in ground ice content, topography, soil type, and permafrost coverage. Together, these modifying factors determine (i) the degree to which permafrost thaw manifests as thermokarst, (ii) whether thermokarst leads to slumping or the formation of thermokarst lakes, and (iii) the manner in which constituent delivery to freshwater systems is altered by thaw. Differences in thaw-enabled constituent delivery can Published by Copernicus Publications on behalf of the European Geosciences Union. J. E. Vonk et al.: Effects of permafrost thaw on Arctic aquatic ecosystemsbe considerable, with these modifying factors determining, for example, the balance between delivery of particulate vs. dissolved constituents, and inorganic vs. organic materials. Changes in the composition of thaw-impacted waters, coupled with changes in lake morphology, can strongly affect the physical and optical properties of thermokarst lakes. The ecology of thaw-impacted lakes and streams is also likely to change; these systems have unique microbiological communities, and show differences in respiration, primary production, and food web structure that are largely driven by differences in sediment, dissolved organic matter, and nutrient delivery. The degree to which thaw enables the delivery of dissolved vs. particulate organic matter, coupled with the composition of that organic matter and the morphology and stratification characteristics of recipient systems will play an important role in determining the balance between the release of organic matter as greenhouse gases (CO 2 and CH 4 ), its burial in sediments, and its loss downstream. The magnitude of thaw impacts on northern aquatic ecosystems is increasing, as is the prevalence of thaw-impacted lakes and streams. There is therefore an urgent need to quantify how permafrost thaw is affecting aquatic ecosystems across diverse Arctic landscapes, and the implications of this change for further climate warming.

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Section: 2)mentioning

confidence: 99%

Reviews and syntheses: Effects of permafrost thaw on Arctic aquatic ecosystems

et al. 2015

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“…The extrapolation of results from well-studied lakes of the Mackenzie Delta region of Canada [9,[91][92][93][94], the Yakutia alasses and yedoma lakes [20,95,96], to much larger territories of boreal plains such as the WSL peatlands, and North-Siberia and Yana-Indigirka lowlands, remains unwarranted. The lakes of these lowlands may stand apart from other studied lakes of the subarctic, in view of their high peat context, low pH, shallow depth, and very low salt content.…”

Section: Stock Of Doc and Metals In Thermokarst Lakes Of The Wslmentioning

confidence: 99%

Size Distribution, Surface Coverage, Water, Carbon, and Metal Storage of Thermokarst Lakes in the Permafrost Zone of the Western Siberia Lowland

Polishchuk

Bogdanov²,

Polishchuk

et al. 2017

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Despite the importance of thermokarst (thaw) lakes of the subarctic zone in regulating greenhouse gas exchange with the atmosphere and the flux of metal pollutants and micro-nutrients to the ocean, the inventory of lake distribution and stock of solutes for the permafrost-affected zone are not available. We quantified the abundance of thermokarst lakes in the continuous, discontinuous, and sporadic permafrost zones of the western Siberian Lowland (WSL) using Landsat-8 scenes collected over the summers of 2013 and 2014. In a territory of 105 million ha, the total number of lakes >0.5 ha is 727,700, with a total surface area of 5.97 million ha, yielding an average lake coverage of 5.69% of the territory. Small lakes (0.5-1.0 ha) constitute about one third of the total number of lakes in the permafrost-bearing zone of WSL, yet their surface area does not exceed 2.9% of the total area of lakes in WSL. The latitudinal pattern of lake number and surface coverage follows the local topography and dominant landscape zones. The role of thermokarst lakes in dissolved organic carbon (DOC) and most trace element storage in the territory of WSL is non-negligible compared to that of rivers. The annual lake storage across the WSL of DOC, Cd, Pb, Cr, and Al constitutes 16%, 34%, 37%, 57%, and 73%, respectively, of their annual delivery by WSL rivers to the Arctic Ocean from the same territory. However, given that the concentrations of DOC and metals in the smallest lakes (<0.5 ha) are much higher than those in the medium and large lakes, the contribution of small lakes to the overall carbon and metal budget may be comparable to, or greater than, their contribution to the water storage. As such, observations at high spatial resolution (<0.5 ha) are needed to constrain the reservoirs and the mobility of carbon and metals in aquatic systems. To upscale the DOC and metal storage in lakes of the whole subarctic, the remote sensing should be coupled with hydrochemical measurements in aquatic systems of boreal plains.

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“…The majority of available studies addressed the carbon and element transformation in the permafrost regions via analysis of rivers (Lobbes et al, 2000;Striegl et al, 2005;Spencer et al, 2008Holmes et al, 2012;Wickland et al, 2012;Giesler et al, 2014;Mann et al, 2015), lakes (Kokelj et al, 2005(Kokelj et al, , 2009Guo et al, 2007;Laurion et al, 2010;Tank et al, 2009), mires (Olefeldt and Roulet, 2012;Olefeldt et al, 2013Olefeldt et al, , 2014 or soil organic matter (SOM) from various depth and soil aqueous leachate (Swindles et al, 2015;Hodgkins et al, 2014Hodgkins et al, , 2016Drake et al, 2015;Vonk et al, 2015a;Yang et al, 2016) and largely ignored soil porewater chemistry. At the same time, interstitial soil solutions are known to be efficient tracers of ongoing bio-geochemical processes in the critical zone (Hendershot et al, 1992;Stutter and Billett, 2003;Quinton and Pomeroy, 2006;Karavanova and Malinina, 2007;Gangloff et al, 2016) and can help to decipher the intensity of carbon and metals migration from the soil to the rivers and further to the ocean.…”

Section: Introductionmentioning

confidence: 99%

Dissolved organic carbon and major and trace elements in peat porewater of sporadic, discontinuous, and continuous permafrost zones of western Siberia

et al. 2017

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Abstract. Mobilization of dissolved organic carbon (DOC) and related trace elements (TEs) from the frozen peat to surface waters in the permafrost zone is expected to enhance under ongoing permafrost thaw and active layer thickness (ALT) deepening in high-latitude regions. The interstitial soil solutions are efficient tracers of ongoing bio-geochemical processes in the critical zone and can help to decipher the intensity of carbon and metals migration from the soil to the rivers and further to the ocean. To this end, we collected, across a 640 km latitudinal transect of the sporadic to continuous permafrost zone of western Siberia peatlands, soil porewaters from 30 cm depth using suction cups and we analyzed DOC, dissolved inorganic carbon (DIC), and 40 major elements and TEs in 0.45 µm filtered fraction of 80 soil porewaters.Despite an expected decrease in the intensity of DOC and TE mobilization from the soil and vegetation litter to the interstitial fluids with the increase in the permafrost coverage and a decrease in the annual temperature and ALT, the DOC and many major and trace elements did not exhibit any distinct decrease in concentration along the latitudinal transect from 62.2 to 67.4 • N. The DOC demonstrated a maximum of concentration at 66 • N, on the border of the discontinuous/continuous permafrost zone, whereas the DOC concentration in peat soil solutions from the continuous permafrost zone was equal to or higher than that in the sporadic/discontinuous permafrost zone. Moreover, a number of major (Ca, Mg) and trace (Al, Ti, Sr, Ga, rare earth elements (REEs), Zr, Hf, Th) elements exhibited an increasing, not decreasing, northward concentration trend. We hypothesize that the effects of temperature and thickness of the ALT are of secondary importance relative to the leaching capacity of peat, which is in turn controlled by the water saturation of the peat core. The water residence time in peat pores also plays a role in enriching the fluids in some elements: the DOC, V, Cu, Pb, REEs, and Th were a factor of 1.5 to 2.0 higher in mounds relative to hollows. As such, it is possible that the time of reaction between the peat and downward infiltrating waters essentially controls the degree of peat porewater enrichments in DOC and other solutes. A 2 • northward shift in the position of the permafrost boundaries may bring about a factor of 1.3 ± 0.2 decrease in Ca, Mg, Sr, Al, Fe, Ti, Mn, Ni, Co, V, Zr, Hf, Th, and REE porewater concentration in continuous and discontinuous permafrost zones, and a possible decrease in DOC, specific ultraviolet absorbency (SUVA), Ca, Mg, Fe, and Sr will not exceed 20 % of their current values. The projected increase in ALT and vegetation density, northward migration of the permafrost boundary, or the change of hydrological regime is unlikely to modify chemical composition of peat porewater fluids larger than their natural variations within different micro-landscapes, i.e., within a factor of 2. The decrease in DOC and metal delivery to small rivers and lakes by peat soil ...

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The influence of thermokarst disturbance on the water quality of small upland lakes, Mackenzie Delta region, Northwest Territories, Canada

Cited by 135 publications

References 25 publications

Reviews and syntheses: Effects of permafrost thaw on Arctic aquatic ecosystems

Reviews and syntheses: Effects of permafrost thaw on Arctic aquatic ecosystems

Size Distribution, Surface Coverage, Water, Carbon, and Metal Storage of Thermokarst Lakes in the Permafrost Zone of the Western Siberia Lowland

Dissolved organic carbon and major and trace elements in peat porewater of sporadic, discontinuous, and continuous permafrost zones of western Siberia

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