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1. Resilience and Adaptation: Yukon River Watershed Contaminant Risk Indicators

   https://doi.org/10.1155/2018/8421513  

   Duffy, Lawrence; De Wilde, La’Ona; Spellman, Katie; Dunlap, Kriya; Dainowski, Bonita; McCullough, Susan; Luick, Bret; van Muelken, Mary (October 2018, Scientifica)

   River watersheds are among the most complex terrestrial features in Alaska, performing valuable ecosystem functions and providing services for human society. Rivers are vital to both estuarine and aquatic biota and play important roles in biogeochemical cycles and physical processes. The functions of watersheds have been used as vulnerability indicators for ecosystem and socioeconomic resilience. Despite a long history of human activity, the Yukon River has not received the holistic and interdisciplinary attention given to the other great American river systems. By using hypothesis-based monitoring of key watershed functions, we can gain insight to regime-shifting stresses such as fire, toxins, and invasive species development. Coupling adaptive risk management practices involving stakeholders with place-based education, especially contaminants and nutrition related, can maintain resilience within communities. The Yukon watershed provides a broadscale opportunity for communities to monitor the environment, manage resources, and contribute to stewardship policy formation. Monitoring keystone species and community activities, such as citizen science, are critical first steps to following changes to resiliency throughout the Yukon watershed. Creating a policy environment that encourages local experimentation and innovation contributes to resilience maintenance during development-imposed stress. 

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2. Late Cenozoic climate change paces landscape adjustments to Yukon River capture

   https://doi.org/10.1038/s41561-020-0611-4  

   Bender, Adrian M.; Lease, Richard O.; Corbett, Lee B.; Bierman, Paul R.; Caffee, Marc W.; Rittenour, Tammy M. (August 2020, Nature Geoscience)

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3. Mercury stocks in discontinuous permafrost and their mobilization by river migration in the Yukon River Basin

   https://doi.org/10.1088/1748-9326/ad536e  

   Smith, M_Isabel; Ke, Yutian; Geyman, Emily_C; Reahl, Jocelyn_N; Douglas, Madison_M; Seelen, Emily_A; Magyar, John_S; Dunne, Kieran_B_J; Mutter, Edda_A; Fischer, Woodward_W; et al (August 2024, Environmental Research Letters)

   Abstract Rapid warming in the Arctic threatens to destabilize mercury (Hg) deposits contained within soils in permafrost regions. Yet current estimates of the amount of Hg in permafrost vary by ∼4 times. Moreover, how Hg will be released to the environment as permafrost thaws remains poorly known, despite threats to water quality, human health, and the environment. Here we present new measurements of total mercury (THg) contents in discontinuous permafrost in the Yukon River Basin in Alaska. We collected riverbank and floodplain sediments from exposed banks and bars near the villages of Huslia and Beaver. Median THg contents were 49⁺¹³/₋₂₁ng THg g sediment⁻¹and 39⁺¹⁶/₋₁₈ng THg g sediment⁻¹for Huslia and Beaver, respectively (uncertainties as 15th and 85th percentiles). Corresponding THg:organic carbon ratios were 5.4^+2.0/_−2.4Gg THg Pg C⁻¹and 4.2^+2.4/_−2.9Gg THg Pg C⁻¹. To constrain floodplain THg stocks, we combined measured THg contents with floodplain stratigraphy. Trends of THg increasing with smaller sediment size and calculated stocks in the upper 1 m and 3 m are similar to those suggested for this region by prior pan-Arctic studies. We combined THg stocks and river migration rates derived from remote sensing to estimate particulate THg erosional and depositional fluxes as river channels migrate across the floodplain. Results show similar fluxes within uncertainty into the river from erosion at both sites (95⁺¹²/₋₄₇kg THg yr⁻¹and 26⁺¹⁵⁴/₋₁₃kg THg yr⁻¹at Huslia and Beaver, respectively), but different fluxes out of the river via deposition in aggrading bars (60⁺⁴⁰/₋₂₉kg THg yr⁻¹and 10^+5.3/_−1.7kg THg yr⁻¹). Thus, a significant amount of THg is liberated from permafrost during bank erosion, while a variable but generally lesser portion is subsequently redeposited by migrating rivers. 

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4. Quantifying river migration rates in the Yukon River Watershed from optical satellite imagery, Alaska, 2016-2022

   https://doi.org/10.18739/A2WW7719J  

   Geyman, Emily; Avouac, Jean-Philippe; Douglas, Madison; Dunne, Kieran; Ke, Yutian; Magyar, John; Reahl, Jocelyn; Seelen, Emily; Smith, Isabel; West, Joshua; et al (January 2024, NSF Arctic Data Center)

   This dataset describes measurements of river migration rates (averaged over the period 2016-2022) in three locations within the Yukon River Watershed: Huslia, Alaska (AK) (65.700 N, 156.387 W), Beaver, AK (66.362 N, 147.398 W), and Alakanuk, AK (62.685 N, 164.644 W). Huslia is located on the Koyukuk River and Beaver and Alakanuk are located on the Yukon River. The river migration rates are quantified from sub-pixel correlation of optical satellite imagery (Sentinel-2 imagery, 10 meter (m) spatial resolution), following the methodology of Geyman et al. (2024). The methodology allows for the detection of riverbank erosion at scales approximately 5-10 times smaller than the pixel size, so the detection threshold is 1-2 m over the approximately 7-year interval, corresponding to a migration rate of 0.1 to 0.3 m/year. The motion of the eroding and accreting sides of the river are quantified separately. The river migration rate datasets are made available as georeferenced shapefiles. 

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5. Mercury content in floodplain sediments from the Yukon River Basin, Alaska, 2022

   https://doi.org/10.18739/A2FX74076  

   Isabel_Smith, M; Blankenship, Rain; Douglas, Madison M; Dunne, Kieran BJ; Fischer, Woodward W; Geyman, Emily C; Ke, Yutian; Magyar, John S; Lamb, Michael P; Mutter, Edda A; et al (January 2024, NSF Arctic Data Center)

   Due to atmospheric circulation and preservation of organic matter, large amounts of mercury (Hg) are stored in permafrost regions. Due to rapid warming and thawing permafrost in the Arctic, this Hg may be released, potentially degrading water quality and impacting human health. River bank erosion in particular has the ability to quickly mobilize large amounts of Hg-rich floodplain sediments. As part of a National Science Foundation (NSF) funded project to better understand the effects of erosion in the Yukon River Basin, floodplain sediments were collected between June and September 2022 at two locations underlain by discontinuous permafrost within the Yukon River Basin: Beaver, Alaska (AK) (65.700 N, 156.387 W) and Huslia, AK (66.362N, 147.398 W). This dataset contains mercury contents for collected floodplain sediments measured by direct thermal decomposition. Sample metadata also includes information recorded in the field (location, visual grain size description, and sample collection depth) and collected post sample processing (water content and dry density). 

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