Fluxes of particulates and nutrients during hydrologically defined seasonal periods in an ice‐affected great Arctic river, the <scp>M</scp>ackenzie
Bibliographic record
Abstract
Abstract Large circumpolar rivers influence the biogeochemistry of coastal shelf ecosystems and Arctic Ocean circulation. From 2007 to 2010, Mackenzie River nutrients were measured immediately upstream of the Mackenzie Delta. Total suspended sediment (TSS) and the dissolved and particulate fractions of carbon, nitrogen, and phosphorus were measured throughout the water year, stratified by hydrologically defined seasonal periods. Sampling was most frequent during the ice breakup and freshet periods to capture changes in sediment and nutrient concentrations that occurred with rapidly changing discharge. Our 4 year sampling coverage yielded constituent‐specific concentration‐discharge relationships that differed among seasonal hydrological periods for 6 of 12 constituents. Results revealed that having data from the rising‐water freshet, when ice effects drive much higher water levels for a given discharge than during open water, had a surprisingly modest effect on annual flux calculations for most constituents. The rising freshet, however, was dominated by high relative levels of C‐rich dissolved organic matter, P‐rich particles, and N‐rich inorganic nutrients. Comparisons with fluxes based on volume‐weighted means of sample concentrations revealed that most, though not all, river fluxes were strongly driven by short‐term concentration‐discharge dynamics rather than by total annual discharge. Comparisons with fluxes derived for the Mackenzie discharge record, where results from other years are available, suggest that concentration‐discharge relations may not be robust beyond the observation period in this system. Constituent fluxes herein differ from previously published fluxes for the Mackenzie (e.g., lower TSS, higher dissolved organic carbon), likely reflecting more frequent measurements, more representative characterization of differing hydrological periods, and possible changes in concentration‐discharge relations during the longer‐term Mackenzie record.
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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 | 0.000 |
| 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 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".