Meta-analysis of the role of zooplankton faecal pellets in ocean carbon export flux
Bibliographic record
Abstract
Abstract Faecal pellets of marine zooplankton play a key role in the biological carbon pump, i.e. all biologically mediated processes by which organic carbon produced by photosynthesis is stored in the ocean’s interior. Numerous factors (size and biomass of faecal pellets, composition and abundance of zooplankton, etc.) can affect the sinking rate of zooplankton faecal pellets and thus the efficiency of their export at depth. A number of quantitative studies of the role of zooplankton faecal pellets in the biological carbon pump have been conducted, focusing either on a region or a type of faecal pellets. These studies highlighted the large variability in the contribution of faecal pellets to carbon fluxes, ranging from 0% to 100%. Here, we used a meta-analysis approach to extract quantitative data on the size, biomass, and role of marine zooplankton faecal pellets in ocean carbon export from 197 scientific articles. Our study focused on the six most studied faecal pellet types (mixed, cylindrical, ellipsoidal, tabular, spherical, and drop-shaped). We showed that abundance and biomass fluxes of faecal pellets, as well as their contribution to particulate organic carbon fluxes, increased with ecosystem productivity, here approximated by surface chlorophyll-a concentration. Furthermore, the fluxes of marine zooplankton faecal pellets (both by abundance and biomass) were positively correlated, and the sampling location, rather than the type of faecal pellet, better explained this correlation. Additionally, sinking rates were strongly correlated with volume, length, and width of faecal pellets, for all faecal pellet types. Sinking rates did not vary with depth, although measurements become scarcer with depth. Our literature review highlights the crucial role of faecal pellets in the biological carbon pump and the need to study less known types of faecal pellets, such as ellipsoidal faecal pellets, and to measure multiple variables on the same samples. Finally, we recommend that modellers wishing to represent faecal pellets in global biogeochemical models choose a constant sinking rate with depth within the range of the quantitative values reported here.
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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 | 0.019 | 0.026 |
| Meta-epidemiology (narrow) | 0.003 | 0.001 |
| Meta-epidemiology (broad) | 0.008 | 0.030 |
| Bibliometrics | 0.018 | 0.017 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.004 | 0.002 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".