Detrital subsidy from subtidal kelp beds is altered by the invasive green alga Codium fragile ssp. fragile
Bibliographic record
Abstract
Invasive species have the potential to alter the dynamics of detrital subsidy from high to low productivity areas through changes in quantity and nutritional quality of detrital material.We examined the effect of the invasive alga Codium fragile ssp.fragile on the nature of detrital export from subtidal algal beds off Nova Scotia, Canada, by comparing changes in mass, nutritional quality (%C, %N, C/N ratio), concentration of dimethylsulfoniopropionate (DMSP, a secondary metabolite that deters grazers), and isotopic composition (δ 13 C and δ 15 N) between C. fragile and the native kelp Saccharina latissima at 4 wk intervals over 16 wk of degradation in cages on a sand bottom at 19 m depth.C. fragile degraded more slowly, and had a consistently lower C/N and higher DMSP concentration, than S. latissima.Isotope signatures did not differ between algal species: δ 15 N became slightly enriched (~1 ‰) after 16 wk of degradation, with no change in δ 13 C.We also compared macrofaunal communities associated with degrading thalli of each algal species and found significantly higher abundances of invertebrates (mainly capitellid polychaetes) on S. latissima after 8 wk of degradation, resulting in lower evenness (J') and diversity (H ') on S. latissima compared to C. fragile.Macrofaunal community composition became similar between algal species at 12 and 16 wk in concordance with decreases in C/N ratio in S. latissima and DMSP concentration in C. fragile.Our results indicate that differences in biochemical composition and the rate of degradation between C. fragile and native kelps result in community-level effects in areas linked to shallow algal beds via the transfer of detritus.
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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 | 0.000 | 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 | 0.001 | 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 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".