Assessing anaerobic activity in perennial subzero hypersaline spring of the high Arctic: focus on methanogenesis, anaerobic oxidation of methane and sulphur reduction
Bibliographic record
Abstract
The Lost Hammer (LH) spring in the Canadian high Arctic perennially discharges subzero (-5°C) hypersaline (24% salt) brines through thick layers of permafrost (> 500 m), and so far accounts for the only described terrestrial methane seep in frozen settings on Earth.The present thesis aimed to ascertain that actively metabolising, indigenous, microbial communities do populate the sediments of the LH spring outlet despite the extreme conditions in situ.Incubation experiments with LH sediments could not confirm Nomenclature and abbreviations 16S rRNA gene: Gene coding for the ribosomal small subunit RNA; the 16S rRNA is used a phylogenetic marker. AOM: Anaerobic oxidation of methane.Astrobiology: The study of the origin, evolution, and distribution of life in the universe.cDNA: complementary DNA; DNA that have been generated by the reverse transcription of a RNA molecule.Chemolithoautotroph: A microorganism that obtains energy through chemical oxidation (chemo), and uses inorganic compounds as an electron (litho) and carbon (auto) sources.cmbs: cm below the sediment surface.Cryoenvironment: Environments which temperature is continuously below 0°C, or which is continuously surrounded by frozen settings.Cryomicrobiology: The study of cryophiles.Cryophile: A cold-adapted microorganism capable of growth below 0°C, regardless of its optimum growth temperature.Cryosphere: Portion of the biosphere that lives in cryoenvironments.Halophile: A microorganism capable of metabolizing under hypersaline conditions.OTU: Operational taxonomic unit; a classification of DNA sequences that have been binned as unique taxonomic units based on similarity/dissimilarity to other sequences.Psychrophile: The term psychrophile is mostly used in the literature to describe coldadapted microorganisms that have growth optima below 20°C; some, but not all, psychrophiles can grow below 0°C.SR: Sulphur reduction; (bio)chemical reduction of a sulphur compound (e.g.sulphate reduction).SRB: Sulphate reducing bacteria.SRM: Sulphur reducing microorganism; microorganisms undergoing the reduction of a sulphur compound (e.g.sulphate) to sulphide (e.g.SRB).xi SRR: Sulphide release rates; the rates of sulphide (H 2 S) production resulting from SR.Sulphidogenesis: The production of sulphides, either chemical or biological.
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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) | 0.000 | 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".