Evidence of a microbial community associated with rock varnish at Yungay, Atacama Desert, Chile
Bibliographic record
Abstract
Rock varnish is a very slow‐growing nanostratigraphic coating consisting of approximately 70% fine‐grained clay and 30% iron and manganese oxides that forms on the surfaces of rocks in arid and semiarid climates. The microbial diversity associated with rock varnish collected from the hyperarid Yungay region of the Atacama Desert was investigated using culture‐independent biomolecular methods and an adenosine triphosphate (ATP) assay. The extraction of DNA from rock varnish collected at Yungay, a region in which little to no DNA has been extracted from the surface soil (<1 cm) to date, indicates that rock varnish may provide a niche habitat for microbial life where water is essentially absent. The clone library constructed suggests the presence of numerous phylogenetically distinct microorganisms, ranging in diversity from Cyanobacterial to á‐proteobacteria lineages. The findings also show that only a few micrometers of varnish material are enough to shelter microbes like Chroococcidiopsis spp. from the intense ultraviolet radiation present in the Atacama Desert. Whether or not microorganisms are involved in its nucleation and/or growth, rock varnish appears to provide a microhabitat resembling cryptoendolithic communities seen on a larger scale.
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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 | 0.001 |
| 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".