Rapid and Gradual Permafrost Thaw: A Tale of Two Sites

Minsley, Burke J.; Pastick, Neal J.; James, S. R.; Brown, Dana R. N.; Wylie, Bruce K.; Kass, M. Andy; Romanovsky, V. E.

doi:10.1029/2022gl100285

Cited by 8 publications

(5 citation statements)

References 41 publications

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“…Thaw, as inferred by the conversion of spruce forest to deciduous forest and scrub in the escarpment and uplands to the east, is likely responsible for allowing more infiltration and opening new groundwater flow paths. Talik formation following wildfires has been well documented (Gibson et al, 2018; Minsley et al, 2022, 2016; O'Neill et al, 2020; Rey et al, 2020; Yoshikawa et al, 2002). The gradual increase in solutes in the lake prior to 2019 is consistent with water movement through deeper active layers or supra‐permafrost taliks that allowed for more water contact with mineral soils and bedrock.…”

Section: Discussionmentioning

confidence: 99%

“…The Bonanza Creek fire near Fairbanks, Alaska is a well-studied example in an environment similar to our study area. There, a 4.15-m-thick talik formed 17 years after fire (Yoshikawa et al, 2002), and geophysical surveys 31-38 years postfire suggested that a talik layer over 5-m thick persisted under 1-3 m of reforming permafrost near the surface (Minsley et al, 2022(Minsley et al, , 2016.…”

Section: Introductionmentioning

confidence: 99%

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Cascading effects of climate change and wildfire on a subarctic lake: A 20‐year case study of watershed change

et al. 2023

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Mean annual air temperature has been increasing in Alaska since the 1970s and is expected to continue to increase through the current century, resulting in significant environmental changes (e.g., permafrost thaw, shifts in vegetation community composition and distribution, increased wildfire frequency and severity). Because there is little long‐term monitoring data available on lake ecosystems in the subarctic it is difficult to predict how lakes will respond. Here we present data from an ~20‐year long‐term lake and climate monitoring program in Interior Alaska. A significant portion of the lake catchment was burned by wildfires in 1986 and again in 2004. As a result, much of the vegetation in the lake catchment was converted from spruce‐dominated forest to deciduous forest, indicating likely permafrost degradation. At a nearby monitoring site absent of fire effects, mean annual ground temperatures at 50 and 90 cm warmed significantly from about −2°C to about −1°C over the 20‐year monitoring period. Warming of similar or greater magnitude is inferred at the study site due to fire effects. Lake water analyses before and after the 2004 fire show a significant postfire increase in dissolved organic carbon, total nitrogen, and total phosphorous that persisted for a short period (~3 years) and was followed by small, but significant, increases in specific conductance and ion concentrations. Approximately 15 years postfire sulfate and cation concentrations in the lake increased exponentially due to the development of a groundwater seep near the lake. The seep likely formed as a result of permafrost thaw creating new subsurface flowpaths in response to long‐term climate warming and fire effects. In 2021, specific conductance and sulfate concentrations reached 657 μS/cm and 71 mg/L respectively, exceeding tolerance thresholds of the water lily Nuphar lutea. In 2021, N. lutea beds that had occupied the lake since 1981 were no longer visible. Depending on local catchment characteristics, source waters and flow paths contributing to small subarctic lakes will continue to evolve uniquely in response to climate change and thawing permafrost. This case study shows the cascading effects of warming soil and wildfires on catchment characteristics as well as terrestrial and aquatic vegetation and lake water chemistry.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Cascading effects of climate change and wildfire on a subarctic lake: A 20‐year case study of watershed change

et al. 2023

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“…The annual number of publications that use ERT in the study of permafrost has increased by an order of magnitude, from two or three to more than 30 (Figure 1), with research sites located in all countries with significant occurrence of permafrost (Figure 2). Diverse applications include assessment of geohazards, 10 examining interactions between permafrost and infrastructure, 11 characterizing permafrost thaw due to climate change 12 and wildfires, 13 validating temperature models, 14 and developing hydrogeologic models. 15 Several factors make ERT surveying in permafrost environments uniquely demanding.…”

Section: Introductionmentioning

confidence: 99%

Best practices for using electrical resistivity tomography to investigate permafrost

Herring,

Lewkowicz,

Hauck

et al. 2023

Permafrost & Periglacial

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Electrical resistivity tomography (ERT) is a minimally invasive geophysical method that produces a model of subsurface resistivity from a large number of electrical resistance measurements. Strong resistivity contrasts usually exist between frozen and unfrozen earth materials, making ERT an effective and increasingly utilized tool in permafrost research. In this paper, we review more than 300 scientific publications dating from 2000 to 2022 to identify the capabilities and limitations of ERT for permafrost applications. The annual publication rate has increased by a factor of 10 over this period, but several unique challenges remain, and best practices for acquiring, processing, and interpreting ERT data in permafrost environments have not been clearly established. In this paper, we make recommendations for ERT surveys of permafrost and highlight recent advances in the field, with the objective of maximizing the utility of existing and future surveys.

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“…Electrical resistivity tomography (ERT) has been used to map permafrost spatial distribution and depth (Arboleda‐Zapata et al., 2022; Minsley et al., 2012; Tran et al., 2018; You et al., 2013), as well as ice‐content if petrophysical relationships and site conditions allow for it (Dafflon et al., 2017). Geophysical imaging has also been used to investigate permafrost dynamics, and has shown that lateral flow may have a significant contribution to the formation of taliks (Uhlemann et al., 2021) and that disturbances, such as wildfires, have a spatially variable and long‐term impact on permafrost systems (Minsley et al., 2022).…”

Section: Introductionmentioning

confidence: 99%

Estimating Permafrost Distribution Using Co‐Located Temperature and Electrical Resistivity Measurements

Uhlemann,

Shirley,

Wielandt

et al. 2023

Geophysical Research Letters

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Assessing the lateral and vertical extent of permafrost is critical to understanding the fate of Arctic ecosystems under climate change. Yet, direct measurements of permafrost distribution and temperature are often limited to a small number of borehole locations. Here, we assess the use of co‐located shallow temperature and electrical resistivity tomography (ERT) measurements to estimate at high‐resolution the distribution of permafrost in three watersheds underlain by discontinuous permafrost. Synthetic modeling shows that co‐located temperature and ERT measurements allow for supervised classification schemes that provide 60% higher accuracy compared to unsupervised methods. Linking resistivity and size of the identified permafrost bodies to surface observations, we show that tall vegetation (>0.5 m) and gentle slopes (<15°) are related to warmer and smaller permafrost bodies, and a more frequent occurrence of taliks.

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Rapid and Gradual Permafrost Thaw: A Tale of Two Sites

Cited by 8 publications

References 41 publications

Cascading effects of climate change and wildfire on a subarctic lake: A 20‐year case study of watershed change

Cascading effects of climate change and wildfire on a subarctic lake: A 20‐year case study of watershed change

Best practices for using electrical resistivity tomography to investigate permafrost

Estimating Permafrost Distribution Using Co‐Located Temperature and Electrical Resistivity Measurements

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