Air‐sea flux of bromoform: Controls, rates, and implications
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
Bromoform (CHBr 3 ) is the largest single source of atmospheric organic bromine and therefore of importance as a source of reactive halogens to the troposphere and lower stratosphere. The sea‐to‐air flux, originating with macroalgal and planktonic sources, is the main source for atmospheric bromoform. We review bromoform's contribution to atmospheric chemistry, its atmospheric and oceanic distributions and its oceanic sources and sinks. We have reassessed oceanic emissions, based on published aqueous and airborne concentration data, global climatological parameters, and information concerning coastal and biogenic sources. The goals are to attempt an estimate of the global source strength and partly to identify key regions that require further investigation. The sea‐to‐air flux is spatially and temporally variable with tropical, subtropical and shelf waters identified as potentially important source regions. We obtain an annual global flux of bromoform of ∼10 Gmol Br yr −1 (3–22 Gmol Br yr −1 ). This estimate is associated with significant uncertainty, arising from data precision and coverage, choice of air‐sea exchange parameterizations and model assumptions. Anthropogenic sources of ∼0.3 (to 1.1) Gmol Br yr −1 (as CHBr 3 ) can be locally significant, but are globally negligible. Our estimate of the global oceanic source is three to four times higher than recent estimates based on the modeling of atmospheric sinks. The reasons for this discrepancy could lie with the limited regional and temporal data available and the broad assumptions that underlie our flux calculations. Alternatively, atmospheric sink calculations, often made on the basis of background CHBr 3 levels, may neglect the influence of strong but highly localized sources (e.g., from some coastal and shelf regions). The strongly variable and poorly characterized source of CHBr 3 , together with its short atmospheric lifetime, complicates model‐based estimation of the distribution of reactive Br resulting from its atmospheric degradation. An integrated program of marine and atmospheric observations, atmospheric modeling and mechanistic studies of oceanic bromoform production is required to better constrain present and future Br delivery to the atmosphere.
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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 it