Microbial degradation of four dispersed crude oils by <i>Rhodococcus</i> sp. evaluated using carbon stable isotope analysis
Bibliographic record
Abstract
Abstract BACKGROUND The high frequency and wide distribution of oil spills pose serious threats to the marine environmental ecosystem and human health. Microbial degradation is considered to be the most applicable means to process oil spills. Carbon isotope fractionation was employed as a crucial tool for evaluating the biodegradation of four crude oils by Rhodococcus sp. with Corexit 9500A as oil dispersant. RESULTS Following biodegradation, carbon isotope fractionation of n ‐alkanes in four dispersed crude oil samples was measured by gas chromatography–isotope ratio mass spectrometry. A relationship between the carbon isotope ratios and residual concentrations of n ‐alkanes was established based upon the Rayleigh equation, with a correlation coefficient, R 2 , ranging from 0.67 to 0.83. The carbon isotope enrichment factors for n ‐alkanes of the four crude oil samples tended to be 0.04–0.25‰ in the residuals. The biodegradation level of n ‐alkanes calculated from the Rayleigh equation agreed with the biodegradation results analyzed by gas chromatography–mass spectrometry. CONCLUSIONS The degree of microbial degradation was positively correlated to the carbon isotope fractionation in n ‐alkanes. Compound‐specific stable isotope analysis is capable of quantifying the biodegradation level of crude oil or oil spills. © 2019 Society of Chemical Industry
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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) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| 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".