Origin and Accumulation of an Anthropogenic CO<sub>2</sub> and <sup>13</sup>C Suess Effect in the Arctic Ocean
Bibliographic record
Abstract
Abstract We determined the impact of anthropogenic CO 2 (C ant ) accumulation on the δ 13 C of dissolved inorganic carbon in the Arctic Ocean (i.e., the 13 C Suess effect) based on δ 13 C measurements during a GEOTRACES cruise in 2015. The δ 13 C decrease was estimated from the amount of C ant change derived by the transit time distribution approach and the ratio of the anthropogenic δ 13 C/dissolved inorganic carbon change (RC). A significant C ant increase (up to 45 μmol kg −1 ) and δ 13 C decrease (up to −0.9‰) extends to ~2,000 m in the Canada and Makarov Basin. We find distinctly different RC values for the intermediate water (300–2,000 m) and upper halocline water (<200 m) of −0.020 and −0.012‰ (μmol kg −1 ) −1 , respectively, which identifies two sources of C ant accumulation from North Atlantic and North Pacific. Furthermore, estimated RC for intermediate waters is the same as the RC observed in the Greenland Sea and the rate of anthropogenic dissolved inorganic carbon increase estimated for intermediate waters at 0.9 μmol kg −1 yr −1 is identical to the estimated rate in the Iceland Sea. These observations indicate that the high rate of C ant accumulation and δ 13 C decrease in the Arctic Ocean is primarily a result of the input of C ant , via ventilation of intermediate waters, from the Nordic Sea rather than local anthropogenic CO 2 uptake within the Arctic Basin. We determine the preindustrial δ 13 C (δ 13 C PI ) distributions and find distinct δ 13 C PI signatures of the intermediate and upper halocline waters that reflect the difference in δ 13 C PI –PO 4 relationship of Atlantic and Pacific source water.
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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 | 0.000 | 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 | 0.000 | 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 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".