Surface to atmosphere carbon exchange in peatlands with permanent open water pools
Notice bibliographique
Résumé
Peatland ecosystems are long-term net carbon (C) sinks but the open water pools that are characteristic of these temperate to subarctic wetlands have been found to be C sources to the atmosphere. Their contribution to the ecosystem level C budget has often been ignored even if they cover a significant area of the peatland surface. There is therefore a question as to whether peatlands containing pools are smaller net sinks of atmospheric C compared to peatlands without pools; the total C loss measured from pools is the same order of magnitude, but with the opposite sign, as the published average net ecosystem carbon balance for pool-free northern peatlands. In this study, I evaluated the annual C release from peatland open water pools, its impact on the net ecosystem carbon dioxide exchange (NEE-CO2) and assessed the NEE-CO2 variability and controls between peatlands with different pool cover.The annual C release from pools was estimated at 103 g C m-2 yr-1, of which 15% was released during the spring ice melt. Although this estimate is within the range of other published studies, my results suggest that previous assessments of C release underestimate the annual loss by not including the spring melt release and by using sporadic measurement techniques. The ecosystem scale measurements performed using the eddy covariance technique (EC) showed that the 30-min maximum CO2 uptake rates decreased by close to 25% for an increase in pool fraction within the EC tower source area from 0-10% to 20-30%. I found that pools lower the overall NEE-CO2 components (maximum photosynthetic uptake and ecosystem respiration rates) by reducing the ecosystem's aboveground vegetation biomass. The lower total vegetation biomass at the ecosystem scale reduced net CO2 uptake during the day but also reduced ecosystem respiration (ER) at night, as ER from the pools is mainly heterotrophic. The net effect was that the site remained a sink for CO2 during the measurement period despite the inclusion of pools. When comparing sites with different pool cover fraction and climate, I observed significant variability in NEE-CO2 and its components between sites, and found that biophysical controls on CO2 exchange previously identified for vegetated surface peatlands (leaf area index, plant functional type) apply to peatlands containing open-water pools. Overall, my results demonstrate that peatland open water pools can play a significant role in the ecosystem level surface to atmosphere C exchange. Measurements of interannual NEE-CO2 variability from different peatlands with pools will expand the validity of these findings. Future studies should also include an evaluation of the annual CH4 exchange, CO2 loss during the winter along with dissolved organic carbon export from peatland with pools in order to obtain a complete net ecosystem carbon balance.
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) | 0,000 | 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 ».