Influence of human disturbance on carbon efflux in a subarctic boreal forest
Notice bibliographique
Résumé
Soil respiration plays a crucial role in the carbon cycle and has significant implications for climate change. Understanding the dynamics of soil respiration in the subarctic and arctic is essential to more accurately predict carbon fluxes and their potential responses to disturbances, as these systems hold an estimated 1,400 Pg of carbon (National Snow and Ice Data Center). This research focuses on two primary objectives: (1) to compare soil respiration rates between undisturbed and disturbed areas located in a boreal forest ecosystem near the town of Fairbanks, Alaska, and (2) to identify the key environmental and geochemical factors influencing soil respiration in these environments. Vegetation at the undisturbed site consists of a black spruce (Picea mariana) canopy, woody shrubs dominated by Labrador tea (Rhododendron tomentosum and groenlandicum), low shrubs (Vaccinium spp.), several mosses (Sphagnum and Spinulum), and reindeer lichen (Cladonia rangiferina). Grasses (Poaceae), sedges (Cyperaceae), and woody shrubs (Salix spp. and Rhododendron tomentosum) constitute the vegetation structure at the disrupted location. The disturbance was caused by trail construction and firewood harvesting. We used an automated carbon dioxide (CO2) and methane (CH4) efflux closed chamber system to measure soil respiration rates over the course of one year. Environmental parameters, including soil temperature, volumetric water content, and seasonal thaw depth, were also measured to assess their influence on soil respiration and to investigate their utility as environmental tracers for impacting C flux, seasonally.Preliminary results indicate that soil respiration rates measured at the disturbed site were higher, 2.43 +/- 0.14 g of C-CO2 m−2/day−1, as compared to the undisturbed area, 2.13 +/- 0.23 g of C-CO2 m−2/day−1. Average soil temperature and water content were -0.53 °C and 0.24 m3/m3 respectively in the undisturbed soils. The disturbed site had a higher average soil temperature of 0.30 °C, while maintaining the same soil water content value of 0.24 m3/m3. Maximum seasonal thaw depths at the undisturbed sites were approximately 1/3, -58 +/- 3 cm, as compared to the disturbed sites, -148 +/- 29 cm. These differences are likely due to the change in vegetation cover, which contributes to elevated soil respiration rates.These findings show that disturbance events enhance soil respiration rates, possibly due to the deepening of the active layer, unlocking carbon in organic matter that is metabolized by the soil microbial communities. The increased soil respiration in the disturbed area may be attributed to the disruption of the original vegetation cover (e.g., moss and black spruce), which leads to an increased soil temperature and accelerated decomposition of organic matter. These findings highlight the importance of considering land disturbances for carbon models and suggest that vegetation disturbance can be used as a proxy for landscape-scale active layer dynamics in subarctic regions. The results contribute to our understanding of the carbon cycle in these ecosystems. Further research is needed to investigate the long-term effects of disturbances on soil respiration and to refine our understanding of the underlying mechanisms driving these processes.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
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 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 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) | 0,001 | 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 ».