Organic matter incorporation into sea ice and potential matter release into the nearshore zone of the southern Beaufort Sea, Canada
Notice bibliographique
Résumé
Global warming, mainly caused by human influences, has become much more severe in recent decades. While the average temperature of the Earth has increased of about 0.8°C over the time period of the entire last century, the temperature has increased by 0.6°C over only the past 30 years (GISTEMP, 2016; Lenssen et al., 2019). The Arctic region has warmed more than twice as fast as the global average (Serreze et al., 2009; Screen and Simmonds, 2010). This accelerated heating has dramatic effects on a wide range of fields including the thawing and re-freezing processes of permafrost soils. Almost a quarter of the land area of the northern hemisphere is influenced by permafrost at around 23 million km2. When the permafrost thaws, the active layer deepens and the annual thawing phase of the permafrost soils becomes longer. A result of the thawing is the associated soil water mobility and an increased rate of erosion, causing more sediment and dissolved organic carbon (DOC) to be deposited in lakes, rivers, groundwater fluxes and coastal waters. In this work, sea ice cores and water from the water column below were sampled from the coastal area in the southern Canadian shelf of the Beaufort Sea, near Herschel Island - Qikiqtaruk, in order to investigate the possible incorporation of organic substances and the release from winter land-fast ice. The samples were collected from two intersecting transects, before the beginning of the melting season in spring 2019. Analyses of DOC, colored dissolved organic matter (CDOM), salinity, water isotope ratios as well as suspended particulate matter (SPM) were made, to gain information on how organic matter has been incorporated and released during the winter freeze up and through the season. The measured DOC-, CDOM- and SPM-concentrations are relatively low compared to sea ice concentrations measured in other studies. Isotopes and salinity measurements show decreasing freshwater and river influences at the south side of transect 1 through the winter, meaning that the freshwater source petered out through the course of winter and through that giving indication of the river as the organic matter source. Results also showed a significantly higher SPM concentrations at the near shore north side of transect 1 and the west near shore side of transect 2. The data obtained from this study show how sensitive the regions of the Arctic and their material and carbon fluxes react to rising temperatures and suggest that coastal erosion can occur already as early as part of the winter season.
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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 | 0,002 | 0,003 |
| Études des sciences et des technologies | 0,004 | 0,001 |
| Communication savante | 0,001 | 0,000 |
| Science ouverte | 0,001 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 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 ».