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1. Linking permafrost to the abundance, biomass, and energy density of fish in Arctic headwater streams

   https://doi.org/10.1002/ecs2.70270  

   Carey, Michael P; Koch, Joshua C; O'Donnell, Jonathan A; Poulin, Brett A; Zimmerman, Christian E (May 2025, Ecosphere)

   Abstract Permafrost thaw alters groundwater flow, river hydrology, stream‐catchment interactions, and the availability of carbon and nutrients in headwater streams. The impact of permafrost on watershed hydrology and biogeochemistry of headwater streams has been demonstrated, but there is little understanding of how permafrost influences fish in these ecosystems. We examined relations among permafrost characteristics, the resulting changes in water temperature, stream hydrology (e.g., discharge flashiness), and macroinvertebrates, with the abundance, biomass, and energy density of juvenile Dolly Varden (Salvelinus malma) and Arctic Grayling (Thymallus arcticus) across 10 headwater streams in northwestern Alaska. Macroinvertebrate density was driven by concentrations of dissolved carbon and nutrients supporting stream food webs. Dolly Varden abundance was primarily related to water temperature with fewer fish in warmer streams, whereas Dolly Varden energy density decreased with the flashiness of the headwater streams. Dolly Varden biomass was related to both temperature and bottom‐up food web effects. The energy density of Arctic Grayling decreased with warmer temperatures and discharge flashiness. These relations demonstrate the importance of terrestrial–aquatic connections in permafrost landscapes and indicate the complexity of landscape effects on fish. Because permafrost thaw is one of the most impactful changes occurring as the Arctic warms, an improved understanding of how stream temperature, hydrology, and bottom‐up food web processes influence fish populations can aid forecasting of future conditions across the Arctic. 

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2. Geochemical phosphorus sequestration in tundra soils limits primary production in Arctic headwater streams and rivers. Upper Kuparuk River, North Slope, Alaska, 2020-2023.

   https://doi.org/10.18739/A2348GJ1Z  

   Sutor, Frederick (January 2024, NSF Arctic Data Center)

   Climate warming in the Arctic region is thawing previously frozen soil (permafrost). Permafrost thaw alters landscape hydrology, increases weathering rates, and thus increases the delivery of solutes to adjacent waters. Long-term monitoring of the Kuparuk River (North Slope, Alaska) confirms significant increases in many solutes that are indicative of thawing permafrost. However, there is no evidence of an increase in phosphorus (P), the nutrient that most often limits primary production in tundra streams. Here, we show that soils in the upper Kuparuk River watershed have a high biogeochemical sorption capacity that can limit P mobility and use published data to show that this may be a pan-Arctic characteristic. While P bioavailability is restricted by vegetative cycling, we found that concentrations of Mehlich-3 extractable iron (Fe) and aluminum (Al) also impart a very high P geochemical sorption capacity across our study sites. Analysis of a pan-Arctic soils database suggests that this high P sorption capacity could be a ubiquitous feature of Arctic soils. Therefore, we conclude that while warming-induced permafrost thaw may increase P mobility, simultaneous increases in pedogenic secondary Fe/Al minerals will continue to retain P in tundra soils and limit biological productivity in adjacent aquatic systems. 

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3. Biogeochemical phosphorus sequestration in tundra soils impedes delivery of bioavailable phosphorus to an Arctic headwater river: Implications for the broader Arctic region

   https://doi.org/10.22541/essoar.173884252.27595895/v1  

   Sutor, Frederick William; Roy, Eric D; Schroth, Andrew; Michaud, Alexander B; Emerson, David; Herndon, Elizabeth M; Kinsman-Costello, Lauren; Hurley, Stephanie; Bowden, William Breck (February 2025, ESS Open Archive)

   Climate warming in the Arctic is thawing previously frozen soil (permafrost). Permafrost thaw alters landscape hydrology and increases weathering rates, which can increase the delivery of solutes to adjacent waters. Long-term river monitoring of the Kuparuk River (North Slope, Alaska, USA) confirms significant increases in solutes that are indicative of thawing permafrost. However, there is no evidence of an increase in total phosphorus (TP) or soluble reactive phosphorus (SRP), the nutrient that limits primary production in this and similar rivers in the region. Here, we show that Mehlich-3 extractable iron (Fe) and aluminum (Al) impart high P biogeochemical sorption capacities across a range of landscape features that we would expect to promote lateral movement of water and solutes to headwater streams in our study watershed. Reanalysis of a recently published pan-Arctic soils database suggests that this high P sorption capacity could be common in other parts of the Arctic region. We conclude that while warming-induced permafrost thaw may increase the potential for P mobility in our watershed, simultaneous increases in pedogenic secondary Fe and Al minerals may continue to retain P in these soils and limit biological productivity in the adjacent river. We suggest that similar interactions may occur in other areas of the Arctic where comparable biogeochemical conditions prevail. 

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4. Ground Penetrating Radar data surrounding beaver ponds in Alaska tundra, 2021

   https://doi.org/10.18739/A20K26C7K  

   Clark, Jason; Tape, Ken (January 2022, NSF Arctic Data Center)

   In recent decades, beavers have reportedly extended their range from the boreal forest into the arctic tundra, altering tundra streams and surrounding permafrost at local to regional scales. In lower latitudes, beaver damming can convert streams, backwaters, and lake outlets into connected ponds, which in turn can change the course of channels, temperature of streams, sediment loads, energy exchange, aquatic habitat diversity and nutrient cycling, and riparian vegetation. In the Arctic, effects of beavers may include enhanced thawing of permafrost, increased stream temperatures, and changes in seasonal ice in streams, as well as complex ecosystem responses. This study will 1) document movement of beavers from the forest into tundra regions, 2) understand how stream engineering wrought by beavers will change the arctic tundra landscape and streams, and 3) predict how beavers will expand into tundra regions and alter stream and adjacent ecosystems. Results will be of interest to local communities and resource managers, and the team of investigators will convene a scientist and stakeholder workshop in Fairbanks, Alaska to synthesize observations, compare results from studies in temperate ecosystems, and clarify impacts of beaver expansion unique to the tundra biome. In August 2021 we used a ground penetrating radar (GPR) to image the subsurface surrounding beaver ponds in a tundra region around Nome, Alaska. The general objective was to determine if heat from new beaver ponds are impacting permafrost. We used a Mala GX GPR (Mala Ground Explorer GPR) with a 450mhz antenna and an integrated DGPS (differential global positioning system). GPS (global positioning system) location data is stored in the .cor file. 

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5. Geochemical Weathering Variability in High Latitude Watersheds of the Gulf of Alaska

   https://doi.org/10.1029/2023JF007284  

   Jenckes, J; Muñoz, S; Ibarra, D E; Boutt, D F; Munk, L A (March 2024, Journal of Geophysical Research: Earth Surface)

   Abstract High latitude regions across the globe are undergoing severe modifications due to changing climate. A high latitude region of concern is the Gulf of Alaska (GoA), where these changes in hydroclimate undoubtedly affect the hydrogeochemistry of freshwater discharging to the nearshore ecosystems of the region. To fill the knowledge gap of our understanding of freshwater stream geochemistry with the GoA, we compile stream water chemistry data from 162 stream sites across the region. With an inverse model, we estimate fractional contributions to solute fluxes from weathering of silicate, carbonate, and sulfide minerals, and precipitation. We assess weathering rates across the region and compare them against global river yields. The median fractional contribution of carbonate weathering to total weathering products is 78% across all stream sites; however, there are several streams where silicate weathering is a dominant source of solutes. Weathering by sulfuric acid is elevated in glacierized watersheds. Finally, cation weathering rates are lower in GoA streams compared to the world's largest rivers; however, weathering rates are similar when compared to a global dataset of glacier fed streams. We suggest that hydrologic changes driven by glacier ice loss and increased precipitation will alter river water quality and chemical weathering regimes such that silicate weathering may become a more important source of solutes and sulfide oxidation may decrease. This contribution provides a platform to build from for future investigations into changes to stream water chemistry in the region and other high latitude watersheds. 

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