This thesis is comprised of two manuscripts that focus on diatom ecological change through a late Holocene record from a 116.2 cm freeze core obtained from Danny’s Lake, Northwest Territories, Canada. The diatom results indicate that climate in this region has been relatively stable through the past 3330 cal. yr BP, although three distinct diatom assemblages are recognized. Time-series analysis was also carried out on select diatom species from the Danny’s lake sediment core. We correlate the c. 89 and c. 145 year cycles with the 90 – 140 year Gleissberg cycle, while the c. 309-year cycle is attributed to the 300-year overtone of the 2115-year Hallstadt cycle. This research is part of a multi-proxy project mandated to determine late Holocene climate variability along the route of the economically important Tibbitt to Contwoyto Winter Road (TCWR), a seasonal ice road that stretches 600 km from Yellowknife to Nunavut.