The 16S rDNA microbiome of the Arctic foraminifera Neogloboquadrina pachyderma is comprised of hydrocarbon-degrading bacteria and a diatom chloroplast store
Bibliographic record
Abstract
Abstract. Neogloboquadrina pachyderma is the only true polar species of planktonic foraminifera. It therefore plays a crucial role in the calcite flux, and in reconstructions and modelling of seasonality and environmental change within the high latitudes. The rapidly changing environment of the polar regions of the North Atlantic and Arctic Oceans poses challenging conditions for this (sub)polar species in terms of temperature, sea-ice melt, calcite saturation, ocean pH and contraction of the polar ecosystem. To model the potential future for this important high latitude species, it is vital to investigate the modern ocean community structure throughout the annual cycle of the Arctic to understand the inter-dependencies of N. pachyderma. We use 16S rDNA metabarcoding and TEM to identify the microbial interactions of N. pachyderma during the summer ice-free conditions in Baffin Bay. We demonstrate that the N. pachyderma diet consists of diatoms and bacteria. The core microbiome is defined as the 16S rDNA amplicon sequencing variants (ASVs) found in 80 % of individuals investigated. This core microbiome consists of two diatom chloroplast ASVs and seven bacterial ASVs and accounts for, on average, 50 % of the total ASVs in any individual. The bacterial ASVs represent hydrocarbon-degrading bacteria, including those found routinely in the diatom phycosphere. On average the two chloroplast ASVs compose 40 % of the core microbiome. Significantly, an average of 55.7 % of all ASVs in any individual are of chloroplast origin. TEM highlights the importance of diatoms to this species, conclusively revealing that chloroplasts remain undigested in the foraminiferal cytoplasm in very high numbers, comparable to those observed in kleptoplastic benthic foraminifera. Diatoms are the major source of kleptoplasts in benthic foraminifera and other kleptoplastic groups, but this adaptation has never been observed in a planktonic foraminifer. Further work is required to understand the association between N. pachyderma, diatoms and their chloroplasts in the pelagic Arctic realm. It may confer an advantage to this species for survival in this extreme habitat, but it could also become compromised by the rapidly changing climate.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 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 source (direct Gemma or distilled Codex), 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".