Unexpected food web responses to low dissolved oxygen in an estuarine fjord
Bibliographic record
Abstract
In coastal marine ecosystems, the depletion of dissolved oxygen can cause behavioral and distributional shifts of organisms and thereby alter ecological processes. We used the spatiotemporal variation in the onset and intensity of low dissolved oxygen in Hood Canal, Washington, USA, to investigate consequences of seasonally reduced oxygen on fish-zooplankton predator-prey interactions. By simultaneously monitoring densities of zooplankton (primarily the euphausiid; Euphausia pacifica) and zooplanktivorous fish (Pacific herring, Clupea pallasii, and Pacific hake, Mercluccius productus), and the feeding of zooplanktivorous fish, we could separate the effects of dissolved oxygen on fish-zooplankton interactions from other seasonal changes. We expected that fish predators (especially Pacific herring) would be less abundant and have lower feeding rates when oxygen levels declined below biological thresholds, and that this would result in increased zooplankton abundance in areas with lowest dissolved oxygen. However, these expectations were not borne out. Overall, there was mixed evidence for an effect of dissolved oxygen on many of our response variables, and when effects were detected, they were frequently in the opposite direction of our expectations. Specifically, the pelagic fish community became more abundant (as measured by increasing acoustic backscatter), which was particularly pronounced for Pacific herring. Zooplankton had weak evidence for a response to dissolved oxygen, but the direction was negative instead of positive. Although predator feeding composition was unrelated to dissolved oxygen, stomach fullness (an index of feeding intensity) of Pacific herring declined, as per our expectations. These unexpected findings highlight the importance of in situ measurements of multiple aspects of predator-prey linkages in response to environmental stress to enhance our ability to predict ecological consequences of declining oxygen.
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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 | 0.001 |
| 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".