Impacts of elevated pCO2 on trace gas emissions in two microalgae: Phaeocystis globosa and Nitzschia closterium
Bibliographic record
Abstract
Environmental context Ocean acidification can affect marine microalgae, which can produce climate-active trace gases such as dimethylsulfide and various halocarbons. We conducted monoculture experiments simulating future ocean acidification, and showed that trace gas emissions are affected by elevated pCO2 to different degrees. The responses of trace gases to elevated pCO2 are compound- and species-specific. Abstract The potential impacts of seawater acidification on the concentrations of dimethylsulfide (DMS), dimethylsulfoniopropionate (DMSP), dissolved acrylic acid (AAd) and various volatile halocarbons, including CH3Cl, CHBr3, CH2Br2, CHBr2Cl, CHBrCl2 and CH3I, were examined during a laboratory CO2 perturbation experiment for the microalgae Phaeocystis globosa and Nitzschia closterium. The microalgae were exposed to ambient CO2 conditions (390–540 µatm; 1 µatm = 0.1 Pa) and to projected concentrations for the end of the century (760–1000 µatm, high carbon (HC)). The growth rate of the two species remained unaffected by elevated CO2. Results showed a 48 and 37 % decline in the DMS concentration normalised to cell density in P. globosa and N. closterium cultures in the HC treatment compared with the ambient treatment. No significant difference was observed for DMSPp and DMSPd in the two microalgae cultures between the two CO2 levels. The mean AAd concentrations in the P. globosa culture showed a 28 % decline in the HC treatment. By contrast, the cell-normalised concentrations of AAd in the HC treatment were 45 % lower than in the ambient treatment in N. closterium cultures. No CO2-induced effects were observed for CH3Cl, CHBr3, CHBr2Cl, CHBrCl2 and CH3I, but cell-normalised concentrations of CH2Br2 in N. closterium cultures showed a 32 % decline in the HC treatment relative to the ambient level. These results show that the metabolism processes responsible for the production of climate-active gases in phytoplankton may be affected by high CO2 levels. There may be a potential delay in the responses of trace gas emissions to elevated pCO2.
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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) | 0.002 | 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".