The fate of biologically produced methane in an anoxic fjord in British Columbia
Notice bibliographique
Résumé
Our climate is currently experiencing changes unlike those seen before in history.An increase of methane gas in the atmosphere has been shown to exacerbate these changes, much more so than an increase in carbon dioxide.Methanogens are microscopic organisms that produce methane, and live in oxygen poor environments.Methanotrophs are other microscopic organisms that consume methane, and can live in environments with or without oxygen.Both of these organisms can live and interact in an anoxic fjord; an environment containing areas with and without oxygen.Methane created by methanogens is consumed by methanotrophs, but it is not known if all the methane produced is consumed or if some reaches the surface and diffuses into the atmosphere.A perfect area to study this is Effingham Inlet, in British Columbia, Canada.Effingham Inlet contains two basins, one with oxygen throughout the basin and one that has both an oxic and anoxic zone.Six water samples were taken in both basins.Methane concentration and cell abundance were measured in each sample.Samples were also taken to determine if genes necessary for methanogenesis and methanotrophy were present.The presence of these genes indicates the presence of methanogens and methanotrophs, respectively.There was a strong increase in cell abundance in the anoxic zone of the upper basin, along with a relatively high methane concentration.The presence of methane in the anoxic zone along with an increase in cell abundance suggests the presence of methanogens.The absence of a high concentration of methane above the anoxic layer suggests that methanotrophs are present, and have consumed most if not all of the methane produced through methanogenesis. ABSTRACTThis study examined an anoxic fjord in British Columbia, Canada, to try to get a better understanding of what happens to biologically produced methane.Six samples were taken in two basins of the fjord, one with oxygen throughout the water column and one with both an oxic and anoxic layer.Methane concentrations were quantified using a gas chromatograph-flame ionization device, and microorganisms were quantified using fluorescence microscopy.DNA extraction and PCR amplification were performed on the key genes of both methanogenesis and methanotrophy, to determine if any methanogens and/or methanotrophs were present in each sample.Microbial abundance increased in the anoxic layer of the upper basin to approximately 1.5x10 6 cells mL -1 , along with relatively high methane concentrations (0 ppm in the surface to ~50 ppm at depth).The presence of methane in the anoxic layer along with an increase in cells suggests the presence of methanogens.The absence of a high concentration of methane above the anoxic layer suggests that methanotrophs were present, and had consumed most if not all of the methane produced through methanogenesis.
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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,001 | 0,001 |
| Études des sciences et des technologies | 0,004 | 0,001 |
| Communication savante | 0,002 | 0,000 |
| Science ouverte | 0,001 | 0,001 |
| Intégrité de la recherche | 0,001 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».