NWT RESEARCH DATABASE

Regions: Inuvialuit Settlement Region

Tags: aquatic ecosystems, biology, paleoecology, benthic invertebrates, paleontology, delta lakes

Objective(s): To examine the effects of permafrost and flooding on the ecological structure and carbon exchange of contrasting lakes in the Mackenzie River Delta.

Project Description: This study will examine the effects of permafrost and flooding on the ecological structure and carbon exchange of contrasting lakes in the Mackenzie River Delta. Patterned ground marked by ice-wedge polygons is formed by freezing and thawing of the soil, which forms cracks into which ice can spread and cause the soil to uplift. These processes have effects on the hydrology and water chemistry of adjacent aquatic environments, and these factors can control the composition of invertebrates in the sediments. Flooding caused by ice jams is also an important factor in many lakes in the Mackenzie Delta, particularly those adjacent to the main channels. Lakes exposed to flooding in the spring receive an influx of nutrients and a period of increased connectivity to other aquatic habitats, and these factors are also expected to have an effect on the invertebrate composition. The objective is to understand the importance of these factors on lake ecosystem function in the Mackenzie Delta based on sediment records, and how this understanding can be used to predict and monitor future changes. The research team will use helicopter access to collect water samples (1 Litre) from Mackenzie Delta lakes, and use a boat to collect water samples from lakes in the vicinity of Inuvik. The research team will be using a multi-parameter probe (YSI) to measure depth, water temperature, pH, conductivity and dissolved oxygen. Water samples (~2L) will be collected using pre-cleaned plastic bottles, by collecting samples from just below the water surface. Two sediment cores will be extracted from each lake (gravity corer, 8.4 cm diameter), and transported back to the lab for processing. Algae, zooplankton, and benthic invertebrates for food web analysis will be collected. These samples will be brought back to the Aurora Research Institute for preservation and processing. The research team is available to give presentations about the research to interested community organizations. Once the research is complete, the team will prepare a poster that can be displayed at the Aurora Research Institute that outlines the findings. The research team will also send copies of any publications that result from this research to the Aurora Research Institute library. The fieldwork for this study will be conducted from July 21, 2014 to August 15, 2014.