Macumber, A.L., Neville, L.A., Galloway, J.M., Patterson, R.T., Falck, H., Swindles, G.T., Crann, C., Clark, I., Gammon, P., Madsen, E. 2012. Climatological assessment of the Northwest Territories and implications for the long-term viability of the Tibbitt to Contwoyto Winter Road, Part II: March 2010 Field Season. NWT Open Report 2011-010, 83 p.
We characterize water quality and present biological and chemical data from lake sediments in support of an NSERC Strategic Project mandated to investigate background climate variability over the past ca. 3500 years in the southern Northwest Territories (NT). Goals of the project “Paleoclimatological assessment of the central Northwest Territories: Implications for the long-term viability of the Tibbitt to Contwoyto Winter Ice Road” include providing data to increase the understanding of natural climate variability in the southern NT in general, and the Tibbitt to Contwoyto Winter Road (TCWR) in particular. A complete understanding of past climate systems is critical to predicting future climate variability and impacts on northern ecosystems.
Eighteen lakes were sampled during March 2010 (Appendix C – Table C01): a total of thirteen freeze cores, sixty Glew cores, twenty sediment-water interface samples, twenty bottom and top water samples and twenty vertical lake profiles were collected. The eighteen lakes samples are spread along a latitudinal transect that spans the length of the TCWR from Tibbitt Lake to Lac de Gras. Lake sediment cores are composed mainly of mud, although a few contain intervals of sand and gravel. Freeze coring was performed with a custom designed device that captured sediments on two faces and was successful in capturing the unconsolidated sediment-water interface. Sediment cores were digitally imaged and sedimentologically described and a subset was X-Ray imaged. Limnological properties and chemical characterization of lake water will be used in concert with analyses of sediment-water interface samples to develop thecamoebian (arcellacean) and diatom-based transfer functions. These transfer functions will be used to quantify the paleoclimate record of the central NT over the past 3000 years. This research represents the first analysis of fossil and modern assemblages of arcellaceans in the southern NT and is only the second investigation involving arcellaceans, after Dallimore et al. (2000), to occur in the territory. Other microfossil techniques, such as palynology and microscopic charcoal analysis, will permit reconstruction of treeline movement and the response of fire regime to past climate change.