Total Alkalinity and Dissolved Inorganic Carbon Production in Groundwaters Discharging through a Sandy Beach
Bibliographic record
Abstract
The paper presents evidence of the complexity of describing carbon transport from submarine groundwater discharge and chemical reactions in the subterranean estuary. Vertical and horizontal profiles of total alkalinity (TA) and dissolved inorganic carbon (DIC) concentrations were analyzed in a cross-shore transect of a sandy beach and an evaluation of DIC and TA fluxes to coastal waters is proposed based on groundwater discharge velocities and beach hydrogeology. The study was conducted in the Magdalen Islands in the Gulf of St. Lawrence (QC, Canada) where an unconfined sandstone aquifer rapidly discharges to the coastal ocean with a rate of ∼3000 m 3 d -1 . Increases in DIC and TA observed along the discharge pathway exceed the expected conservative mixing between inland groundwaters and seawater. This local production is attributed to anaerobic respiration. Slow groundwater velocity (1 to 9 cm d -1 ), low oxygen conditions (∼20%) and redox oscillations probably induced by tidal pumping present a suitable environment for bacterially-mediated carbon oxidation and anaerobic respiration. Depleted δ 13 C-DIC (from −14‰ to −28‰) and the characteristic odour of H 2 S during sample collection support the idea that sulphate reduction may generate high alkalinity and DIC concentrations at the seepage face, leading to potentially high discharge to the coastal ocean at this beach (2.0 to 8.2 mol DIC/day and 1.9 to 7.9 mmol TA/day). To our knowledge, this study is the first attempt to estimate the transport and transformations of dissolved inorganic carbon by biogeochemical processes in the subterranean estuary of a northern sandy beach.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 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 | 0.000 | 0.001 |
| 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 teacher head, 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".