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TitleLake mud: a tool to identify global teleconnections and quantify the range of environmental responses to climate variability in the Northwest Territories, Canada
AuthorMacumber, A L; Patterson, R T; Galloway, J M; Falck, H; Swindles, G T; Crann, C
SourceNorthwest Territories Geoscience Office, Yellowknife Geoscience Forum Abstracts Volume 2013, 2013 p. 41
Alt SeriesEarth Sciences Sector, Contribution Series 20130445
Meeting41st Annual Yellowknife Geoscience Forum; Yellowknife; CA; November 19-21, 2013
File formatpdf
ProvinceNorthwest Territories
Subjectsenvironmental geology; surficial geology/geomorphology; climatic fluctuations; climate, arctic; climate effects; environmental impacts; environmental studies; paleoenvironment; paleoclimates; climate change
Programenvironmental impacts and adaptation in the northern environment, Environmental Geoscience
LinksOnline - En ligne
AbstractRecent climate changes affecting the Canadian Subarctic have prompted policy planners to seek a better understanding of regional climate variability and the range of associated environmental responses. A key concern is the viability of current infrastructure and the necessity to invest in more permanent overland routes. The dearth of consistent long-term records of regional climate has greatly hindered and even precludes the accurate modeling of future climate in the region. Previous studies have tracked coarse temporal scale changes in treeline movement but not at the temporal resolution necessary to identify the oscillatory nature of global teleconnections which contribute to regional climate variability. Also missing is the range of associated environmental responses to historical climate variability. Only when this response is understood can future scenarios of climate models be put into terms of environmental impact.

Global teleconnections, such as the El Niño/Southern Oscillation, are the result of large scale oceanic and atmospheric circulatory processes. They temporally fluctuate at specific frequencies and thus environmental processes they affect, whether directly or indirectly, will record a similar fluctuation within their paleorecords. The particle size distribution of lake sediments represents variability in the energy within the surrounding catchment of the lake. This energy can be modulated by sediment availability, changes in snowpack, presence or absence of vegetation, and average precipitation. These all in turn are modulated by regional climate variability which is the result of the forcing behaviour of global teleconnections. Sediment freeze cores were collected from two boreal subarctic lakes ¿ Waite Lake and Danny¿s Lake ¿ in the Northwest Territories, Canada and were subsampled at millimeter intervals utilizing a custom-designed freeze core microtome. Time series analysis of the grain size distributions identified periodicities equivalent to those seen in records of the El Niño/Southern Oscillation, the Pacific Decadal Oscillation and the Gleissberg Cycle. These results help to clarify which teleconnections are associated with the regional climate variability of the canadian Subarctic.

Biotic proxies are an important tool for tracking historical environmental changes due to climatic variability. Arcellacea are a freshwater protist, which undergo rapid generation times, are resistant to dissolution and are numerous in lake sediments. A suite of geochemical and sedimentological analysis of fifty six lakes spanning North from Yellowknife into the southern arctic ecozone of the Northwest Territories were used to characterize lakes and the arcellacean populations they contain. This information coupled with downcore studies of ancient arcellacean populations can be used to reconstruct an environmental history for the region. These results help to identify important climate events, possible analogue scenarios and define the range of expected environmental response to natural climatic variability.

Altogether these results will provide policy makers and climate modelers with the required information to project possible future climate scenarios and to assess the viability of present and future infrastructure in the Canadian Subarctic.
Summary(Plain Language Summary, not published)
Recent climate change in the Canadian subarctic mean that land use managers requrie a better understanding of climate variability and associated environmental impact. The viability of infrastructure is a concern. Overland transportation routes are critical for the continued success of the mineral-based economy of northern Canada. We use high-resolution analyses of biotic, physical, and chemical signatures preserved in lake sediments from the central Northwest Territories to examine the incidence of global teleconnectsion on the climate of the central NWT. We observe, using time series analysis, periodicities equivalent to the El Niño/Southern Oscillation, the Pacific Decadal Oscillation, and the Gleissberg solar cycle. These results assist in the idenitification of forcing mechanisms of climate in Canada's North.