Fire, drought and permafrost thaw: interactive effects on dissolved organic carbon, mercury, and nutrients in peatland-rich watersheds of boreal western Canada.  
Notice bibliographique
Résumé
Permafrost thaw, wildfires, and increased amplitude of floods and droughts are all aspects of climate change that risk affecting the downstream mobilization of dissolved organic carbon (DOC), the neurotoxin methylmercury (MeHg), and various nutrients from boreal peatlands. In this study, we monitored water chemistry at the outflow of eighteen peatland-rich catchments (125 – 1700 km2) across a climate gradient in boreal western Canada. Our study included a wetter year (2022) and two extreme drought years (2023 and 2024) which also resulted in extensive fires that affected nine of the watersheds in 2023. Flood conditions in 2022 resulted in high hydrological connectivity, particularly in comparison to 2023 and 2024, where drought conditions coupled with extensive wildfires limited connectivity and combusted existing carbon stores. This reduced the mobilization of the co-transported MeHg in streams during the drought years, as well as resulting in no observable effects of the wildfires overall on water chemistry due to this limited connectivity within the peatlands.Peatlands, covering over 30% of the Dehcho Region and Hay River watershed, are likely the primary source of these deleterious solutes due to the biogeochemistry of anoxic waterlogged soils. The goals of this monitoring program were developed collaboratively with the Dene Tha’, K'atl'odeeche, and Dehcho First Nations; their perspectives have been critical for this project. Community members expressed concerns about declining water quality potentially related to climate change, and the associated impacts on ecosystem health and fish resources. To assess the temporal variability of water quality, we studied four creeks with similar catchment sizes and peatland extent along a permafrost gradient using in-situ field sensors and grab samples. Additionally, a Before-After-Control-Impact methodology was used to evaluate the impacts of wildfires on water quality in eighteen streams along a permafrost gradient to assess northern vulnerability. Previous research has observed that peatlands in the discontinuous permafrost zone have poorer hydrological connection to the stream network compared to peatlands south of the permafrost boundary, resulting in higher solute concentrations in the southern region extent. Higher flow conditions during the spring resulted in minor peaks in MeHg and DOC concentrations, with decreasing concentrations as freshet ended. However, warmer temperatures that accelerate microbially associated DOC and MeHg generation resulted in the highest annual concentrations, despite extreme drought conditions that should’ve limited surface water sourcing.Understanding the interactive impacts of permafrost conditions, wildfire and inter-annual climate variability on water quality is essential for managing and protecting the health of northern communities, ecosystems, and food webs. This research provides vital data to inform decision-making, support the resilience of local First Nations, and guide effective environmental stewardship in the face of ongoing climate change. We believe our findings are likely representative of northern peatland-rich regions broadly and will thus be of great interest to understand the global impacts of permafrost thaw and wildfire on carbon and mercury cycling.
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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,001 |
| Études des sciences et des technologies | 0,001 | 0,000 |
| Communication savante | 0,001 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».