Feeding on the edge: δ<sup>13</sup>C analysis of a macrofauna food web from disappearing seagrass beds in a polluted urban harbour – implications for biomonitoring and restoration efforts
Bibliographic record
Abstract
Abstract Thirty‐five macrofaunal species were collected from several eelgrass (Zostera marina) beds in Boston Harbour to determine whether food provenance and carbon flow as measured by δ13C analysis differed for a seagrass community exposed to dense urbanization compared with those documented for populations distant from cities, and whether such isotopic determinations might be used for purposes of biomonitoring such disturbance. In support of other studies and a previous global synthesis, the majority of benthic and epibenthic fauna inhabiting Boston Harbour eelgrass beds were found to have δ13C values within the range, –20 to –17 ‰, indicative of epiphytic algae being the most important food source. However, the proportional abundance‐weighted assessment of the distribution of individual δ13C measurements was found to be quite different from that revealed by non‐quantitative, species‐only assessments. Because the chink shell, Lacuna vincta, which was the only species to demonstrate primary assimilation of eelgrass δ13C, numerically dominated the benthic food web in Boston Harbour, over three‐quarters of the total abundance of macroinvertebrates were likely to be directly dependent upon eelgrass carbon. Nevertheless, food web transfer, as measured through δ15N analysis, was extremely limited as no direct mechanism appeared to presently exist by which eelgrass carbon could be exclusively passed from chink shells to animals of higher trophic positions. The dietary fidelity of these animals while experiencing severe habitat loss due to anthropogenic pollution – neither a shift toward increased vascular plant detritivory nor toward increased planktonic algivory occurred – indicates that pathways of carbon flow may offer little use as an early warning biomonitor for gauging either individual stress or community‐level disturbance from coastal development. Because epiphytic algae are the major food source for most macrobenthos species rather than the vascular plants themselves, the possibility exists that seagrass simulacra might be used as interim installations in order to sustain communities until such time as the aquatic conditions improve to such a degree as to enable the successful restoration of the degraded beds. Copyright © 2013 John Wiley & Sons, Ltd.
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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 | 0.001 | 0.001 |
| 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) | 0.001 | 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".