Canada's mineral security strategy may conflict with obligations to protect at-risk species and Indigenous rights, as in the proposed Grays Bay Road and Port (GBRP), intended to unlock mineral deposits in Nunavut. We integrated harvesting data from three sources — Government of Nunavut harvest records, a community-based caribou surveillance program, and Indigenous Knowledge participatory mapping — on a hexagonal grid to assess overlap between Inuit harvesting of Dolphin and Union (DU) caribou and the proposed corridor. Hotspot analysis identified three harvesting hotspots. The largest lies directly in the GBRP's path — significant at 99% confidence, harvester-confirmed as most important. One hotspot, supported by only two GPS records, was confirmed only through participatory mapping, illustrating the value of combining both data sources. Beyond habitat loss and barrier effects, the GBRP would extend the sea-ice-dependent shipping season DU caribou migration relies on, a pathway outside regulatory scope. These findings indicate the GBRP will harm caribou conservation, food security, and harvesting rights, mitigation unlikely given comparable failures elsewhere. We recommend immediate federal listing of DU caribou as Endangered, evaluation of the GBRP against these hotspots, and enforceable sea-ice mitigation. Divergence among Inuit rights holders over consent disqualifies the GBRP from streamlined federal review.
Despite previous research on under-ice ecology and thermal drivers of productivity, year-round datasets of Arctic lake ecosystem dynamics remain limited. We conducted continuous observations of lake water-column temperatures, water quality and vertical fluxes of organic matter and algal pigments between April 2022 and April 2023 in Lake Kilpisjärvi, Finland. The ultraoligotrophic lake exhibited minor year-round variation in water quality, while distinct seasonal patterns in algal diversity and indicators of production were driven by shifts in thermal structure, including brief spring overturn, weak summer stratification with frequent large-scale wind‑driven mixing, extended autumn overturn, and weak winter inverse stratification. Autumn was the most productive season, with nutrient enrichment from overturn supporting diverse algal communities including diatoms, chrysophytes, cryptophytes, chlorophytes, and cyanobacteria. Spring phytoplankton communities were dominated by siliceous algae. Summer stratification was weak overall with a brief interval of stability that may have limited nutrient availability supporting the development of a deep chlorophyll maximum dominated by motile cryptophytes. Under-ice production was observed in both spring and autumn, but not in winter polar night. The year-round dataset from Lake Kilpisjärvi highlights the key role of thermal processes and wind-driven mixing, offering insights into large Arctic lake ecosystems and informing future monitoring.
Glaucous gulls (Larus hyperboreus) are diet generalists that usually nest in coastal colonies with other species of seabirds, often preying upon their neighbours’ eggs and young. Near a landfill on Cornwallis Island, Nunavut, a colony of glaucous gulls inhabits a small island within Tern Lake where they are the only seabird species nesting. Given that most information of glaucous gull diet comes from birds nesting among other seabirds, this study aimed to determine whether their diet differs from other more typical nearby populations. In addition, we assessed whether these gulls were likely foraging at the nearby landfill. We collected 107 regurgitated glaucous gull pellets from this colony in 2024 and 2025, dissected them, and identified prey items to the lowest possible taxonomic level, as well as any ingested anthropogenic debris. Gulls were feeding predominantly on northern collared lemmings (Dicrostonyx groenlandicus) in both years (frequency of occurrence, FO, of 97%), which contrasts with most previous accounts of glaucous gulls feeding at higher trophic levels on marine prey and young of other seabird species. Other prey items found in this inland colony included mollusk shells, fish vertebrae, bird eggshells, and low amounts of anthropogenic debris including plastic (FO 9%). Our study provides strong evidence of dietary plasticity in glaucous gulls in this inland habitat.
Dissolved organic matter (DOM) concentrations are increasing globally in surface waters—a phenomenon known as browning—especially in northern ecosystems. Browning affects lake mixing, light penetration, oxygen availability, and microbial communities, posing challenges for drinking water safety. In northern communities, where surface water is generally treated without DOM removal, chlorination can produce disinfection by-products (DBPs), such as trihalomethanes (THMs) and haloacetic acids (HAAs), which are regulated for potential health risks. We assessed DBP concentrations in drinking water from eight northern communities in the Northwest Territories, Nunavut, and Nunavik, and examined relationships with DOM quantity and composition. Despite oligotrophic source waters with low dissolved organic carbon (DOC < 6 mg L-1), DBPs were detected in all treated samples, occasionally exceeding Canadian guidelines (up to 109 µg L 1 for THMs and 100 µg L 1 for HAAs). DBP formation correlated primarily with DOC and, secondarily, with pH and DOM optical properties. Regional DOM quality variations—characterized by optical and fluorescence indicators—were linked to DBP composition differences. These findings underscore the vulnerability of northern drinking water systems to DBP formation even under low-DOM conditions, and the importance of DOM quality as a driver of DBP variability. As climate change intensifies browning through precipitation, permafrost thaw, and runoff, DBP risks will rise, requiring enhanced monitoring, improved treatment, and long-term planning.
Surface-based temperature inversions (SBIs) strongly influence near-surface temperatures in subarctic mountain valleys, yet they are poorly represented in coarse-resolution reanalysis datasets. This study evaluated the performance and physical robustness of the Pozsgay and Gruber (2025) inversion correction model in two subarctic valleys along the Dempster Highway, Yukon. The model dynamically adjusts reanalysis air temperature at each timestep using a correction factor derived from the free lower-tropospheric lapse rate and estimated SBI strength allowing for temperature-elevation relationships to vary in response to changing SBI conditions. When calibrated locally, the model reduced mean absolute temperature errors up to 0.8 °C and bias to within ±0.2 °C at the valley scale. Performance was strongest under moderate SBI strength but declined for shallow or very strong SBIs due to limited reanalysis vertical resolution and the assumption of linear lapse rates. Locally calibrated models outperformed transferred ones, indicating sensitivity to local SBI characteristics and limitations associated with absolute elevation-based calibration. Despite these limitations, explicitly accounting for SBI dynamics substantially improves temperature estimates in high-latitude complex terrain. The resulting corrected datasets provide a valuable input for transient permafrost modelling and assessing how changing SBI characteristics may influence ground thermal regimes in subarctic alpine environments.
