Effects of climate change on mercury concentrations in Arctic char, Salvelinus alpinus, in the high Arctic.
Notice bibliographique
Résumé
This thesis is an investigation of linkages of climate change and mercury concentrations in landlocked Arctic char and underlying food webs in Canadian Arctic lakes. Although the neurotoxin mercury is globally present in all environments, temporal and spatial trends in aquatic biota are often inconsistent, or do not exist for remote environments. Knowledge gaps include the influence of abiotic factors, possibly climate, and food web parameters on mercury accumulation in top predators. Furthermore, anthropogenic and natural mercury present in the environment are not well differentiated. To address these research needs, we collected landlocked Arctic char from 27 systems and food web organism from 18 lakes, and recorded abiotic lake characteristics expected to influence mercury cycling. Total mercury (THg) and monomethylmercury (MeHg) concentrations, and stable isotopes of carbon ([delta]13C), nitrogen ([delta]15N), and mercury ([delta]xHg) were determined. Relationships among these measures and with environmental characteristics were investigated. A temporal trend of mercury in Arctic char (muscle tissue) from the largest lake in the Canadian High Arctic from an existing dataset and newly collected char was investigated. Two abundant char morphotypes from Lake Hazen differed in mercury concentrations, and the resulting variability was accounted for using a statistical adjustment. Mercury concentrations did not change over the 16-year period (1990-2006), which is consistent with nearby measurements of gaseous elemental mercury at Alert (Nunavut, Canada). Food chain lengths (FCL) of 18 lakes were characterized, biomagnification of mercury was investigated using [delta]15N, and results compared among regions. Food web biomagnification was confirmed using trophic magnification factors (TMFs) in 18 Arctic char bearing lakes (TMFs 3.5 - 64.3). Benthic coupling was apparent from char [delta]13C signatures that resembled [delta]13C in chironomid midges. TMFs and FCL partly explained THg in adult char, but no latitudinal or other climatic trend was apparent. Mercury concentrations in adult Arctic char were positively related to catchment-to-lake area, and intra-regional, and regional differences in Hg in Arctic char were determined. No climatic factor we investigated was found to affect Hg in char directly; however, predicted climatic changes could affect THg in char indirectly through changes in the catchment (such as melting of permafrost). Stable isotope ratios of mercury revealed region specific mass-independent fractionation (MIF) of up to ~ 4.5 in Arctic char, which did reflect sediment ratios with a constant offset (MIF-factor). High MIF in zooplankton possibly reflected mercury assimilated from the water column. Char from Lake Pingualuk, known pelagic feeders, had high MIF, possibly reflecting an atmospheric Hg signal.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,001 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 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) | 0,000 | 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 tête enseignante, 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 ».