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TitreLate Holocene climatic variability in subarctic Canada: insights from a high-resolution lake record from the central Northwest Territories
AuteurDalton, A S; Patterson, R T; Roe, H M; Macumber, A L; Swindles, G T; Galloway, J M; Vermaire, J C; Crann, C A; Falck, H
SourcePLOS One vol. 13, issue 6, e0199872., 2018 p. 1-21, https://doi.org/10.1371/journal.pone.0199872
Année2018
Séries alt.Ressources naturelles Canada, Contribution externe 20170283
ÉditeurPublic Library of Science
Documentpublication en série
Lang.anglais
DOIhttps://doi.org/10.1371/journal.pone.0199872
Mediaen ligne; numérique
Formatspdf; html
ProgrammeExploration minérale: conditions de base au nord, Géosciences environnementales
Diffusé2018 06 28
Résumé(disponible en anglais seulement)
We examined late Holocene (ca. 3300 yr BP to present-day) climate variability in the central Northwest Territories (Canadian Subarctic) using a diatom and sedimentological record from Danny's Lake (63.48ºN, 112.54ºW), located 40 km southwest of the modern-day treeline. High-resolution sampling paired with a robust age model (25 radiocarbon dates) allowed for the examination of both lake hydroecological conditions (30-year intervals; diatoms) and sedimentological changes in the watershed (12-year intervals; grain size records) over the late Holocene. Time series analysis of key lake ecological indicators (diatom species Aulacoseira alpigena, Pseudostaurosira brevistriata and Achnanthidium minutissimum) and sedimentological parameters, reflective of catchment processes (coarse silt fraction), suggests significant intermittent variations in turbidity, pH and light penetration within the lake basin. In the diatom record, we observed discontinuous periodicities in the range of ca. 69, 88±100, 115±132, 141±188, 562, 750 and 900 years (>90% and >95% confidence intervals), whereas the coarse silt fraction was characterized by periodicities in the >901 and <61-year range (>95% confidence interval). Periodicities in the proxy data from the Danny's Lake sediment core align with changes in total solar irradiance over the past ca. 3300 yr BP and we hypothesize a link to the Suess Cycle, Gleissberg Cycle and Pacific Decadal Oscillation via occasional inland propagation of shifting air masses over the Pacific Ocean. This research represents an important baseline study of the underlying causes of climate variability in the Canadian Subarctic and provides details on the long-term climate variability that has persisted in this region through the past three thousand years.
Résumé(Résumé en langage clair et simple, non publié)
Nous avons analysé une carotte de sédiments lacustres du Canada subarctique et reconstruit le climat en utilisant des assemblages de diatomées depuis 3000 ans. Nous montrons qu'il y a eu des changements importants dans la turbulence, le pH et la pénétration de la lumière à Danny's Lake. En utilisant l'analyse des séries chronologiques de l'abondance de certaines espèces de diatomées et la comparaison avec l'irradiation solaire totale, nous montrons que le climat de la région a été influencé par l'oscillation décennale du Pacifique et la cyclicité solaire.
GEOSCAN ID306277