Organic carbon cycle in the Mackenzie delta lakes

Regions: Inuvialuit Settlement Region, Gwich'in Settlement Area

Tags: physical sciences, aquatic ecosystems, organic carbon, lake sediment, sediment core sampling

Principal Investigator: Lattaud, Julie (2)
Licence Number: 16701
Organization: ETH Zurich
Licensed Year(s): 2020
Issued: Feb 26, 2020
Project Team: Julie Lattaud, Lisa Broder, Maarten Lupker, Daniel Montlucon

Objective(s): To study the dynamics of deltaic lake ecosystems over the past century through the application of recently developed molecular (lipid biomarker) and isotopic (radiocarbon and stable isotopes) proxies to lake sedimentary records.

Project Description: This licence has been issued for the scientific research application No.4698.

The project will study the dynamics of deltaic lake ecosystems over the past century through the application of recently developed molecular (lipid biomarker) and isotopic (radiocarbon and stable isotopes) proxies to lake sedimentary records. This will unravel the impact of old carbon input into aquatic ecosystems. Radiocarbon analysis of different biomarkers will be analysed to trace the different pools of carbon in aquatic ecosystems. Furthermore, the effect of the human-induced warming of the last century will be studied via analysis of sediment cores from multiple deltaic lakes.

Sampling is planned for late winter (March/April 2020), when the lakes in the Delta are still frozen. This facilitates coring (through the ice) since no floating platform needs to be transported. It also enables access via ice roads/skiddoo (assuming the latter proves more cost-effective or practical than transport by helicopter).

Lake sediment cores of different lengths (around 0.5m) will be obtained using simple push core. Aquatic and terrestrial biomarkers such as such as higher plant waxes (n-alkanes), biomarkers for soil and river bacteria, the branched glycerol dialkyl glycerol tetraether lipids and microbial phospholipids fatty acids will be quantified. Subsequently, the radiocarbon composition of these compounds will be obtained in order to understand the different sources and storage of carbon in these three lakes.

The results of this project will be published in international open access peer-reviewed journals. Results will be presented at international conferences. Data will be deposited in open access data repositories, for example MOSAIC (for radiocarbon compositions) and PANGEA. The research team have strong contact with Dustin Whalen (from Natural resource Canada) to build a communication plan for the local community such as visiting school during subsequent sampling campaign and visit to ARI.

The fieldwork for this study will be conducted from March 25, 2020 to April 04, 2020.