Combined Use of Short-Lived Radionuclides (<sup>234</sup>Th and <sup>210</sup>Po) as Tracers of Sinking Particles in the Ocean
Bibliographic record
Abstract
Radionuclides can provide key information on the temporal dimension of environmental processes, given their well-known rates of radioactive decay and production. Naturally occurring radionuclides, such as 234 Th and 210 Po, have been used as powerful particle tracers in the marine environment to study particle cycling and vertical export. Since their application to quantify the magnitude of particulate organic carbon (POC) export in the 1990s, 234 Th and, to a lesser extent, 210 Po have been widely used to characterize the magnitude of the biological carbon pump (BCP). Combining both radionuclides, with their different half-lives, biogeochemical behaviors, and input sources to the ocean, can help to better constrain POC export and capture BCP dynamics that would be missed by a single tracer. Here, we review the studies that have simultaneously used 234 Th and 210 Po as tracers of POC export, emphasizing what can be learned from their joint application, and provide recommendations and future directions.
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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 | 0.006 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.002 | 0.000 |
| Bibliometrics | 0.000 | 0.002 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 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".