Gulls foraging in highly urbanized areas experience disruption in hormones and energetic metabolism
Bibliographic record
Abstract
• Ring-billed gulls are highly exposed to HFRs and PFAS from diffuse urban sources. • Foraging habitat use did not predict plasma HFR and PFAS concentrations in gulls. • Models showed sex-specific linkages between contaminants and metabolism variables. • HFRs were positively correlated with T 3 in males and corticosterone in females. • β-hydroxybutyrate decreased with PFAS in males, although increased in females. Studies on birds breeding in highly urbanized environments have reported high plasma levels of a range of halogenated flame retardants (HFRs) and per- and polyfluoroalkyl substances (PFAS). Exposure of birds to these organohalogens may disrupt hormone regulation and energy metabolism, potentially leading to adverse effects on reproduction and health. While the sources and pathways of exposure to certain of these organohalogens have been documented in several bird populations, little information is available on the exposure-related effects on hormones involved in energy metabolism and their cascading effects on metabolism and energy expenditure. This study aimed to assess the linkages between plasma concentrations of PFAS and HFRs, and thyroid hormones, glucocorticoids, as well as other markers of energy metabolism in nesting ring-billed gulls ( Larus delawarensis) for which foraging movements were tracked for three years in the Montreal area (QC, Canada). Plasma HFR and PFAS concentrations did not vary with foraging habitat use patterns, suggesting diffuse urban sources. Plasma HFR and PFAS concentrations were associated with sex-specific hormonal and metabolic responses. Specifically, lipid-derived β-hydroxybutyrate levels in plasma of males significantly decreased with increasing PFAS concentrations, whereas this relationship was positive in females. Furthermore, triiodothyronine (T 3 ) and β-hydroxybutyrate levels in males and corticosterone in females both significantly increased with those of HFRs. Results suggest that gulls breeding in densely populated urban environments that are highly exposed to organohalogens may experience perturbations of key hormones involved in energy metabolism leading to metabolic effects.
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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 | 0.000 | 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) | 0.001 | 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 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".