Newly discovered deep-branching marine plastid lineages are numerically rare but globally distributed
Bibliographic record
Abstract
Ocean surface warming is resulting in an expansion of stratified, low-nutrient environments, a process referred to as ocean desertification [1Behrenfeld M.J. O’Malley R.T. Siegel D.A. McClain C.R. Sarmiento J.L. Feldman G.C. Milligan A.J. Falkowski P.G. Letelier R.M. Boss E.S. Climate-driven trends in contemporary ocean productivity.Nature. 2006; 444: 752-755Crossref PubMed Scopus (1605) Google Scholar]. A challenge for assessing the impact of these changes is the lack of robust baseline information on the biological communities that carry out marine photosynthesis. Phytoplankton perform half of global biological CO2 uptake, fuel marine food chains, and include diverse eukaryotic algae that have photosynthetic organelles (plastids) acquired through multiple evolutionary events [1Behrenfeld M.J. O’Malley R.T. Siegel D.A. McClain C.R. Sarmiento J.L. Feldman G.C. Milligan A.J. Falkowski P.G. Letelier R.M. Boss E.S. Climate-driven trends in contemporary ocean productivity.Nature. 2006; 444: 752-755Crossref PubMed Scopus (1605) Google Scholar, 2Worden A.Z. Follows M.J. Giovannoni S.J. Wilken S. Zimmerman A.E. Keeling P.J. Environmental science. Rethinking the marine carbon cycle: factoring in the multifarious lifestyles of microbes.Science. 2015; 347: 1257594Crossref PubMed Scopus (421) Google Scholar, 3Archibald J.M. The puzzle of plastid evolution.Curr. Biol. 2009; 19: R81-R88Abstract Full Text Full Text PDF PubMed Scopus (326) Google Scholar]. While amassing data from ocean ecosystems for the Baselines Initiative (6,177 near full-length 16S rRNA gene sequences and 9.4 million high-quality 16S V1-V2 amplicons) we identified two deep-branching plastid lineages based on 16S rRNA gene data. The two lineages have global distributions, but do not correspond to known phytoplankton. How the newly discovered phytoplankton lineages contribute to food chains and vertical carbon export to the deep sea remains unknown, but their prevalence in expanding, low nutrient surface waters suggests they will have a role in future oceans.
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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) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.003 | 0.003 |
| Research integrity | 0.001 | 0.003 |
| Insufficient payload (model declined to judge) | 0.007 | 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".