Low-temperature biodegradation of freshwater dissolved organic matter during winter-to-spring transition
Bibliographic record
Abstract
The composition of dissolved organic matter (DOM) directly affects the biological degradation processes and its persistence in aquatic systems. Spring floods export large amounts of DOM from land into aquatic systems, yet its lability remains largely unknown. This study uniquely investigates the biodegradation of DOM during the critical winter-to-spring transition in seasonally ice-covered marsh and lake environments. We employed a four-bacteria strain inoculum ( Arthrobacter phenanthrenivorans , Bacillus licheniformis , Exiguobacterium sibiricum , and Paracoccus denitrificans) to degrade DOM collected during this period. Using advanced optical and molecular characteristics techniques, we demonstrated significant DOM bioalteration at low temperatures (4°C), which are naturally associated with early spring in cold temperate lakes and wetlands. Despite limited degradation of colored and fluorescent DOM (CDOM and FDOM, respectively), 84% of the mass-to-charge (m/z) peaks detected using positive ion mass spectrometry were lost in winter DOM after 28-day incubation. Biodegradation ranged from 74% to 77% during the spring freshet, with the lowest microbial alteration observed in DOM collected downstream of a marsh at the end of the spring melt season, likely due to increased primary production. These findings highlight the critical role of microbial processes in DOM transformation during periods of rapid hydrological change, providing insights into carbon cycling and ecosystem dynamics in cold aquatic environments.
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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".