Articles tagged with: Yukon

  • New paper by Kevin Turner “Isotopic evidence of increasing water abundance and lake hydrological change in Old Crow Flats, Yukon, Canada”

    A new paper titled, “Isotopic evidence of increasing water abundance and lake hydrological change in Old Crow Flats, Yukon, Canada” co-authored by GeoTour Associate Professor, Dr. Kevin Turner, was recently published in Environmental Research Letters.

    Abstract:
    Lake-rich northern permafrost landscapes are sensitive to changing climate conditions, but ability to track real-time and potentially multiple hydrological responses (e.g. lake expansion, drawdown, drainage) is challenging due to absence of long-term, sustainable monitoring programs in these remote locations. Old Crow Flats (OCF), Yukon, is a Ramsar Wetland of International Importance where concerns about low water levels and their consequences for wildlife habitat and traditional ways of life prompted multidisciplinary studies during the International Polar Year (2007–2008) and led to the establishment of an aquatic ecosystem monitoring program. Here, we report water isotope data from 14 representative thermokarst lakes in OCF, the foundation of the monitoring program, and time-series of derived metrics including the isotope composition of input waters and evaporation-to-inflow ratios for a 13 year period (2007–2019). Although the lakes spanned multiple hydrological categories (i.e. rainfall-, snowmelt- and evaporation-dominated) based on initial surveys, well-defined trends from application of generalized additive models and meteorological records reveal that lakes have become increasingly influenced by rainfall, and potentially waters from thawing permafrost. These sources of input have led to more positive lake water balances. Given the documented role of rainfall in causing thermokarst lake drainage events in OCF and elsewhere, we anticipate increased vulnerability of lateral water export from OCF. This study demonstrates the value of long-term isotope-based monitoring programs for identifying hydrological consequences of climate change in lake-rich permafrost landscapes.

    Reference:
    MacDonald, L.A., Turner, K.W., McDonald, I., Kay, M.L., Hall, R.I., and Wolfe, B.B. (2021). Isotopic evidence of increasing water abundance and lake hydrological change in Old Crow Flats, Yukon, Canada. Environmental Research Letters, 16(12): online.

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  • New research uses leading-edge methods to track a retrogressive thaw slump in Old Crow Flats, Yukon

    Remote sensing graphics from research paper showing research location in Old Crow Flats, Yukon

    A new paper authored by Geography and Tourism Studies Associate Professor, Dr. Kevin Turner, and Geography alumni Michelle Pearce and Daniel Hughes titled “Detailed Characterization and Monitoring of a Retrogressive Thaw Slump from Remotely Piloted Aircraft Systems and Identifying Associated Influence on Carbon and Nitrogen Export” has been published in Remote Sensing. This paper is open-access and available to download here.

    Abstract:
    Ice-rich permafrost landscapes are sensitive to ongoing changes in climate. Permafrost retrogressive thaw slumps (RTSs) represent one of the more abrupt and prolonged disturbances, which occur along Arctic river and lake shorelines. These features impact local travel and infrastructure, and there are many questions regarding associated impacts on biogeochemical cycling. Predicting the duration and magnitude of impacts requires that we enhance our knowledge of RTS geomorphological drivers and rates of change. Here we demonstrate the utility of remotely piloted aircraft systems (RPAS) for documenting the volumetric change, associated drivers and potential impacts of the largest active RTS along the Old Crow River in Old Crow Flats, Yukon, Canada. RPAS surveys revealed that 29,174 m3 of sediment was exported during the initial evacuation in June 2016 and an additional 18,845 m3 continued to be exported until June 2019. More sediment export occurred during the warmer 2017 summer that experienced less cumulative rainfall than summer 2018. However, several rain events during 2017 were of higher intensity than during 2018. Overall mean soil organic carbon (SOC) and total nitrogen (TN) within sampled thaw slump sediment was 1.36% and 0.11%, respectively. A combination of multispectral, thermal and irradiance (derived from the RPAS digital surface model) data provided detailed classification of thaw slump floor terrain types including raised dry clay lobes, shaded and relatively stable, and low-lying evacuation-prone sediments. Notably, the path of evacuation-prone sediments extended to a series of ice wedges in the northern headwall, where total irradiance was highest. Using thaw slump floor mean SOC and TN values in conjunction with sediment bulk density and thaw slump fill volume, we estimated that 713 t SOC and 58 t TN were exported to the Old Crow River during the three-year study. Findings showcase the utility of high-resolution RPAS datasets for refining our knowledge of thaw slump geomorphology and associated impacts.

    Citation:
    Turner K.W., Pearce M.D., and Hughes D.D. (2021). Detailed Characterization and Monitoring of a Retrogressive Thaw Slump from Remotely Piloted Aircraft Systems and Identifying Associated Influence on Carbon and Nitrogen Export. Remote Sensing, 13(2):171. https://doi.org/10.3390/rs13020171

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  • Dr. Kevin Turner returns from fieldwork in northern Yukon

    Dr. Kevin Turner and graduate students, Joe Viscek and Brent Thorne, recently returned from completing fieldwork in northern Yukon where they’re investigating the influence of changing climate and landscape conditions (fire and erosion) on lakes and rivers. Here are some photos from their time in the field. Learn more about Dr. Turner’s research.

    Kevin Turner working in the field

    Kevin Turner doing fieldwork in the Yukon

    Joe Viscek doing fieldwork in the Yukon with Kevin Turner

    Brent Thorne doing fieldwork in the Yukon with Kevin Turner

    Kevin Turner - fieldwork photo from the Yukon

    Photos by Kevin Turner and Brent Thorne.

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