Base de données de recherche des TNO

Régions: Dehcho Region, South Slave Region

étiquettes: carbon budget, organic carbon

Objectif(s): The primary objective of this funded project is to develop a sophisticated model that can simulate the mobilization, transport, transformations, and export of tDOC from the Mackenzie River watershed to the Arctic Ocean. The model will be used to simulate the transfer of tDOC during the past two decades and for plausible future scenarios.

Description du projet: This licence has been issued for the scientific research application No. 6147. The primary objective of this funded project is to develop a sophisticated model that can simulate the mobilization, transport, transformations, and export of tDOC from the Mackenzie River watershed to the Arctic Ocean. The model will be used to simulate the transfer of tDOC during the past two decades and for plausible future scenarios. As part of the project, we will conduct multiple field campaigns to collect crucial data that will facilitate the development and validation of that model. To achieve this objective, we will need to collect 1) field measurements by deploying optical water-quality probes and other optical instruments, 2) water samples for analyses and experiments carried out in the laboratory at Boston University. We will also collect field measurements to develop better algorithms that will facilitate the accurate mapping of surface water- quality indicators (turbidity, algae, tDOC) from NASA ocean-color satellites (https://oceancolor.gsfc.nasa.gov) in Great Slave Lake, as well as in the Mackenzie River and its primary tributaries (e.g., Liard, Hay, Slave). Final deliverables from this project will include: 1) a significant data set of water quality measurements, 2) a modeling framework of tDOC transfer in the Mackenzie River, 3) simulations of tDOC transfer for past two decades and the near future, analyses of change, 4) maps of water quality indicators of Great Slave Lake, the Mackenzie River and its primary tributaries (e.g., Liard, Hay, Slave) derived from NASA satellite sensors, and 5) graduate student training (2 Ph.D. dissertation and multiple peer-reviewed publications). For the field work effort, we hope to be able to leverage help from the local communities of Fort Simpson, Hay River, Kakisa, Fort Providence, and Fort Resolution. Marlene Evans (Environment and Climate Change Canada), who is collaborator on the NASA project, will serve as a link between PI FIchot/Co-I Kaiser and the local communities. She is also helping to develop a companion ECCC program for remote sensing studies of Great Slave Lake and measurements of productivity (chlorophyll). We will conduct field work during a fourth year. We have conducted four field campaigns between September 2022 and September 2024 for sampling and data collection in the tributaries of the Mackenzie River and Great Slave Lake, and we met and engaged with the local communities. During these trips, we engaged with the communities of Fort Resolution (Akaitcho and Métis), Hay River (Katlodeeche), and Fort Simpson (Liidlli Kue), and worked with members of these communities to facilitate sampling on Great Slave Lake and its tributaries. During our field effort of 2025, we will engage with the same members of the local communities to facilitate our sampling activities through the use of local boats to sample on Great Slave Lake. We will collect optical and water-quality data and water samples at different times and multiple locations in Great Slave Lake, the Hay River, Liard River, Kakisa River, Mackenzie River (Fort Providence area), Slave River, and opportunistically in smaller river in-between (Buffalo, Little Buffalo). Optical and water-quality data and water samples will be collected as follows: 1. Water-quality indicators from a YSI EXO-2 sonde (https://www.ysi.com/exo2) equipped with a temperature- salinity probe, a chlorophyll-a fluorescence probe, a dissolved organic matter fluorescence probe, a turbidity probe, and a dissolved oxygen probe. The sonde will be dunked in the water and will be used to acquire data for 2-3 minutes while a water sample is collected at the same time. 2. Water reflectance (color of the water) will be measured at the sampling sites using an ASD handheld spectrometer (https://www.malvernpanalytical.com/en/products/product-range/asd-range/fieldspec- range/fieldspec-4-standard-res-spectroradiometer). This is an above water measurement that is equivalent to taking a picture. 3. A water sample will be collected at each sampling site. The sample will be filtered on site using a simple syringe + in-line filter apparatus (0.7-??m pore size). The filtrate will be collected in a 40-mL small glass vial and analyzed at Boston University for dissolved organic carbon (DOC) (using a Shimadzu TOC-V analyzer) and Chromophoric Dissolved Organic Matter (using a Perkin-Elmer Lambda 650 spectrophotometer). The filter itself will also be kept and analyzed for particulate organic carbon (POC) at Boston University (using a Costech CHN elemental analyzer). 4. Water samples will be collected and transported back to the laboratory Boston for photochemical experiments. Additionally, we are working closely with the GNWT Environment and Natural Resources (ENR) for the long-term deployments of several fluorescence sensors to be mounted the GNWT ENR YSI EXO-2 sondes they are deploying. The sensors were deployed in 2023 and 2024 in the Hay River, Liard River, Slave River, and in the Mackenzie River near Fort Simpson area. The sondes will be deployed in 2025 again and will continuously record water-quality indicators (temperature-salinity, chlorophyll- a fluorescence, dissolved organic matter fluorescence, turbidity, dissolved oxygen). Communication of results will occur through several venues including telephone calls, emails, zoom meetings, and in-person meetings during the entirety of the project. We will also visit Hay River, Fort Resolution, and Fort Simpson to discuss our study, show results, and address questions. The results of the greater NASA project will also be communicated by the PI and co-I teams at the NASA ABoVE science team meetings (https://above.nasa.gov) and at international science meetings such as the American Geophysical Union (AGU) meeting in the late Fall of each year. We have already attended multiple Zoom meetings, organized with Fort Resolution (Diane Giroux, Kathleen Fordy, Annie Boucher with the Akaitcho), Fort Simpson (Mike Low with the Deh Cho), and Hay River (Peter Redvers with the Katlochee First Nation) and have had telephone conversations/email communications with Fort Providence (Priscilla Canadien), and the Fort Resolution (Shawn McKay) and Hay River Metis (Trevor Beck). We have also had Zoom conversations with GNWT (Jennifer Hickman, Robin Staples, and Bruce Hanna) ENR (Guylaine Ross) during which we discussed how to coordinate our proposed sampling with their community-based water quality program and related studies. Marlene Evans (Environment and Climate Change Canada) who is collaborator on the NASA project, will serve as a link between PI FIchot/Co-I Kaiser and the communities and will facilitate communication. As mentioned above, we will also visit in November for the sole purpose to communicate our findings to the local communities. The fieldwork for this study will be conducted from: May 01 - May 20, 2025 November 01 - November 08, 2025