Stress response of a freshwater clam along an abiotic gradient: too much oxygen may limit distribution
Bibliographic record
Abstract
Summary Distribution and abundance patterns are influenced by cellular responses to abiotic stressors. The freshwater clam Sphaerium sp. inhabits swamp/stream systems in Uganda, in which dissolved O 2 (DO), pH and water transparency form ecotonal gradients along tributary streams. Along a swamp/stream transect, clam abundance was negatively related to DO, pH and transparency; clams were most abundant in the hypoxic/acidic swamp, less abundant in the ecotone, and absent from stream sites (neutral pH and higher DO). We tested the hypothesis that individuals living in low abundance at the distribution edge have increased stress by assessing cellular‐level stress indicators in clams from four sites: dense swamp interior (reference site), swamp margin, ecotone and stream. Compared with swamp interior clams, stream clams had decreased RNA : DNA ratio (decreased protein synthesis and growth) and increased DNA and RNA oxidation (free radical damage). Of seven stress proteins related to general damage and free radical detoxification, expression of nearly all were higher in margin and ecotone clams than in swamp interior or stream clams. This pattern, which includes the first measurement of DNA and RNA oxidation in a natural population, demonstrates that stress increases along the transect, inversely to clam abundance. Additionally, this pattern is consistent with free radical stress, which suggests that inhabiting swamp conditions minimizes oxidative damage in this species.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 | 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) | 0.019 | 0.001 |
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; both teacher heads agree on what is shown here.
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".