Seasonal landscape variability in drivers of dissolved organic carbon concentrations in headwater streams draining forested catchments
Notice bibliographique
Résumé
Dissolved organic carbon (DOC) is an important component of aquatic ecosystems, as it influences many parameters within freshwater ecosystems and is transported from upland forests and soils through groundwater and stream flow to aquatic systems via hydrological flowpaths. Recent increases in 'lake browning' have been investigated but the mechanisms underpinning these increases are not entirely understood. One hypothesis is that climate-driven changes in hydrology may result in changes in DOC export from forested catchments. This thesis explored how climate-driven variability in hydrological flowpaths influenced catchment DOC concentrations in headwater streams draining three forested Precambrian shield catchments in northwestern Ontario. The main objectives of this research were to: 1) examine long-term annual and seasonal patterns in DOC concentrations across catchments with varying topography to determine relationships between DOC concentration and hydrological drivers; and 2) investigate DOC transport dynamics during high-flow events to assess how differences in flowpaths and hydrological condition result in variability in stream DOC concentrations among catchments and seasons. Chapter 2 explored patterns and trends of DOC concentration and export among catchments and seasons and explored inter-catchment variability in l1atterns ofDOC concentrations by examining the relationships with chemical and hydrological parameters. Chapter 3 explored how catchment characteristics and hydrological conditions interact to affectDOC concentrations by investigating transport dynamics during high-flow events and by evaluating relationships between DOC and varying antecedent moisture conditions (AMCs). Long-term data demonstrated that differences in DOC concentration among catchment and seasons were driven by differences in flowpath, antecedent moisture and discharge. The wetland-dominated catchment had the highest concentrations of DOC and exhibited inverse relationships between DOC concentrations and discharge; DOC sources were proximal to the stream and transport within this catchment was typically source-limited. The two upland catchments displayed nearly opposite results compared to the wetland-dominated catchment: DOC concentrations were lower, relationships were positive between DOC and discharge, ROC sources were distal to the stream and transport within these two upland catchments was generally transport-limited. This thesis suggests that the hydrologic pathways, especially during high-flow events, are different for each of the study catchments and were activated at different times depending on size, proportion of wetland and AMCs within each catchment.
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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 | 0,001 |
| 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 | 0,000 | 0,001 |
| 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) | 0,001 | 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 ».