Rhizosphere bacteria and fungi are differentially structured by host plants, soil mineralogy, and ectomycorrhizal communities in the Alaskan Tundra
Bibliographic record
Abstract
The rhizosphere contains diverse groups of bacteria and fungi living near plant roots and mycorrhizal hyphae whose composition and function are key drivers of ecosystem and biogeochemical processes. Despite rich literature on rhizosphere communities, no studies have examined the drivers of rhizosphere communities across plants or soil types in the tundra. We collected 513 root samples from 141 individual plants representing six plant species and three mycorrhizal association types across four glacial histories in Northern Alaska. Glacial drifts ranged from 11 000 to 4.5 million years since deglaciation representing a gradient in glacial history and mineralogical weathering. We found that glacial history, a strong proxy for soil mineralogy, explained the most variation in rhizosphere bacterial communities (13.3%) while interactions between glacial history and host plants explained the most variation in fungal rhizosphere communities (11.6%). We found strong correlations between ectomycorrhizal and rhizosphere communities across spatial scales and sites for the shrub Betula nana (30.7%–54.7% correlated), and that ectomycorrhizal composition was most similar among root fragments of the same plant, followed by plants at the same site, and plants at different sites. This work serves to advance the ecological understanding of rhizosphere and ectomycorrhizal communities in response to shrubification.
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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 | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".