Seasonal landscape variability in drivers of dissolved organic carbon concentrations in headwater streams draining forested catchments
Bibliographic record
Abstract
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.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".