Andrew Medeiros and Dr. Roberto Quinlan|
2006 Field Season
Paleolimnological examination of Climate Impacts to Invertebrate communities of Arctic Lakes
The impacts of climate change on the aquatic systems of the Canadian Arctic spans multiple scales of hierarchy. However, the realized impacts on the food web of these systems are poorly understood. It is therefore necessary to identify the influence of climate change on the active hydrological zones of Arctic lakes and ponds. Even a slight thawing of the permafrost layer would cause these aquatic systems to have a greater interaction with the active soil matrix, and possibly drain in the dryer months. The subsequent alteration of the water balances in these systems is perceived to have significant impact on invertebrate community structure. To aid in a directed sampling of lakes and ponds with perceived climatic impacts, satellite image processing (Remote Sensing change detection analysis) was utilized to identify land cover and hydrological changes during the last two decades. In order to understand how climate warming will impact invertebrate community structure, a biogeographic approach is being undertaken to examine multiple lakes and ponds within multiple regions of Nunavut. During 2007, soft sediments from lakes and ponds in the vicinity of Iqaluit, Rankin Inlet, Arviat and Baker Lake will be sampled. The extruded sediments will then be processed in a biostratigraphic approach to quantify past temperature using the fossilized remains of the Family Chironomidae (head capsules of aquatic midges). The examination of the community structure of these invertebrates throughout the sediment profile will then be used to reconstruct past temperature within the last 150 years. Shifts in community structure from cold-water adapted species to warm-water adapted taxa would also be an indicator of recent climate warming.
Andrew Medeiros and Jamal Shirley
Biomonitoring of Arctic streams
Arctic freshwater streams and rivers are highly specialized systems that are susceptible to a wide variety of anthropogenic disturbances. The examination of bio-indicators that respond to changes in temperature, dissolved oxygen, nutrients, and pollutants can thus be used to infer the overall health of these systems. In order to establish a long-term monitoring program to assess the ecological integrity of these systems, these indicators are used to determine any deviation from the established baseline conditions. Since most monitoring protocols in use are based off of research in southern temperate systems, the assessment of Arctic tundra streams requires the development of predictive reference model. As there are also no measures of what a ‘pristine’ habitat is, a reference condition approach is necessary to determine the baseline conditions of the benthic invertebrate communities of undisturbed streams. Thus, comparing ‘pristine’ and ‘disturbed’ benthic invertebrate communities in Nunavut streams will require a model and indices to distinguish the threshold values for qualitative labels of health. This investigation will initially examine the benthic invertebrate community composition in Airport Creek and the Apex River in Iqaluit starting in June 2007. The continued biomonitoring of these streams, as well as others across Nunavut, will allow for a continuous assessment of the health of multiple stream systems across the territory.
Rankin Inlet, 2006 - Lake Coring|
Iqaluit, 2007 - Airport Creek
Iqaluit, 2007 - Assessing the Scene
Iqaluit, 2007 - Festuca Grasses
Iqaluit, 2007 - Poa Grass