Base de données de recherche des TNO

Régions: Inuvialuit Settlement Region, Gwich'in Settlement Area

étiquettes: aquatic ecosystems, climate change

Objectif(s): The aim of this research is to understand how aquatic ecosystems in the Mackenzie Delta region are responding to the impacts of climate change.

Description du projet: This licence has been issued for the scientific research application No. 6195. The aim of this research is to understand how aquatic ecosystems in the Mackenzie Delta region are responding to the impacts of climate change. We are proposing to carry out two parallel projects, both part of graduate research work, related to the research we have done in the region over the last 15 years. In the first we will focus on the impacts of saltwater inundation in the outer Mackenzie Delta region. Our previous research assessed the impacts of the 1999 storm surge in the area of low-lying delta lakes, documenting major changes in chemistry and biology. Since then we have not tracked how lakes have recovered, or perhaps, if they have not recovered. Also, it is possible that other storm surges may have interrupted any further lake ecosystem recovery. We proposed to return to these lakes in 2020, but COVID-19 caused us to cancel that work. We are now hoping to return and re-sample lakes that we last visited in 2009 to track how the ecosystems have changed over the recent past. In project two we hope to continue work on upland ecosystems impacted by permafrost thaw. In the western uplands polygonal terrain that is undergoing thaw is resulting in new pond / shallow lake formation. We are interested in assessing them chemical nature and biological communities of these new water bodies, in order to compare this new lake type with other lakes impacted by permafrost, such as from a long history of retrogressive thaw slumping. We believe this will provide important context and baseline information for tracking how these lakes evolve over time, and put this form of permafrost thaw impacts on aquatic ecosystems in the context of other well-studied examples in this region. The methods we will employ are the same suite of activities that we have used to understand environmental change in lakes of the region over the last ~15 years of work. This focuses on collecting samples of water to analyze chemistry and the algae living in the lake water, as well as cores of lake sediments to track changes over time. For both of these activities lakes are visited, with travel facilitated by helicopter with PCSP support. We then sample either via chest waders (in very shallow ponds), via an inflatable raft that is paddled out onto the lake, or from the pontoons of the helicopter with fixed floats. The choice depends on how much time needs to be spent at a lake and the distance travelled to sample them. Lakes in the outer delta "Dead Zone" from the 1999 storm surge will b sampled by floats, with the new lakes in the western uplands sampled by raft or waders. We collect water in ~1 L bottles from the surface, to be analyzed in a laboratory for standard chemical parameters. We collect sediment cores (they are ~8 cm in diameter and about 60 cm long) using a gravity weighted device lowered into the mud. The plug of mud is removed via its own suction and then capped and taken back to the lab to be sectioned. The mud provides a history book of lake changes that can be used to infer ecosystem changes over hundreds of years of history, depending on the lake. Communications throughout the project are of the utmost importance to our research group. We are currently working on a series of short videos about the work that we do as a research group (including field and lab methods) that demonstrates and clearly explains the nature our research approach. We believe these are highly valuable because they can be shared widely and viewed by interested parties on their own schedule, as time allows. We intend to do the same communications, producing videos, for the results of all of our work as well. For example, the samples collected in the summer of 2023 are just now finished being analyzed by 2 graduate students, who are finishing their theses, and so we are committed to sharing the results of this work in the next couple of months. In addition, we regularly work closely with long-time collaborators at the GNWT, especially in the Northwest Territories Geological Survey as well as at Aurora College. This facilitates the results of our research being put into the context of all of the other excellent work being carried out across the NWT, especially around environmental change and permafrost. We will also share formal research outputs (graduate theses, research papers) on our lab and institutional website, as well as all data derived from the work, for future use by any and all interested parties. The fieldwork for this study will be conducted from: July 02 - July 16, 2025