Methylmercury dynamics at the upland‐peatland interface: Topographic and hydrogeochemical controls
Bibliographic record
Abstract
Peatlands are important environments for the transformation of atmospherically deposited inorganic mercury into the bioaccumulative form, methylmercury (MeHg), which may accumulate in downstream aquatic biota, particularly in fish. In recent research, it was suggested that MeHg production and/or accumulation “hot spots” at the upland‐peatland interface were the result of upland fluxes of sulfate and labile dissolved organic carbon (DOC) into the peatland margin. Along the upland‐peatland interface, spatial heterogeneity of “hot spots” was thought to be a result of variations in upland hydrologic interaction with the peatland margin. This hypothesis was tested in this study. Pore water MeHg, sulfate, and dissolved organic carbon (DOC) concentrations were compared in peatland plots at the base of both topographically concave and linear upland subcatcments in Minnesota. Subcatchment contributing areas were 3–8 times larger in the peatland plots adjacent to areas of concave upland topography. Peat pore water MeHg concentrations were significantly higher in these plots. Fluxes of water, sulfate, and dissolved organic carbon (DOC) from the upland hillslope into the peatland margin were also generally much larger than those from below areas of concave upland topography. Taken together, these results suggest that watershed geomorphology plays an important role in controlling chemical fluxes into peatland margins and consequently MeHg production and accumulation. It may thus be possible to delineate areas of high MeHg production and/or accumulation in certain watersheds by using high‐resolution topographic data. The resulting MeHg “hot spots” may be important for locally foraging biota and for downstream loading, especially in the spring and fall.
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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 | 0.000 |
| 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".