NWT RESEARCH DATABASE

Regions: Inuvialuit Settlement Region, Gwich'in Settlement Area

Tags: physical sciences, water sampling, climate change, Mackenzie River, biogeochemistry

Objective(s): To directly observe seasonally strongly variable organic carbon concentrations and chemistry of the Mackenzie River and thus its fluxes to Arctic coastal waters.

Project Description: This licence has been issued for the scientific research application No.5542. The proposed project aims to directly observe seasonally strongly variable organic carbon concentrations and chemistry of the Mackenzie River and thus its fluxes to Arctic coastal waters. The research team aim for weekly observations of Mackenzie River biogeochemistry during a period covering the major phases of the hydrological year (winter under-ice flow, spring break-up and freshet, summer flow, and freeze back in fall) with a focus on the loads and quality of dissolved organic carbon. These observations will help to identify potentially changing environmental processes within the catchment, such as permafrost thaw, that are linked to climate change. The research method applied is regular sampling of river water from the Mackenzie River East Channel within the town of Inuvik. The exact sampling location will be chosen jointly with WARC personnel at the beginning of the project during the visit of the applicants. Requirements include safe and easy access to the shoreline or ice throughout the project period and a location upstream of potential sources of contamination, such as boat landing stages. During periods of sufficient ice cover, samples will be taken from below the ice through a hole drilled in the ice. During ice break-up, freeze-up and the ice-free period, samples will be taken from the riverbank. On each sampling day, a one-liter plastic bottle and a simple-to-use device to measure water electrical conductivity, temperature and depth (CTD) are taken to the river. The 1 L bottle is rinsed with river water and filled, and the conductivity and temperature of the river water are measured with the CTD at the sampling location. Back at Western Arctic Research Center (WARC), the sample is split into four subsamples for subsequent analyses: Dissolved Organic Carbon (DOC), Colored Dissolved Organic Matter (CDOM), stable water isotopes, and a backup sample for other analyses. The DOC and CDOM subsamples are filtered through a syringe filter into their bottles. The DOC subsample is acidified with HCl. These subsamples are then stored in a cooler/freezer at WARC until shipment to Germany for analyses at Alfred Wegener Institute (AWI’s) hydrochemistry lab. In collaboration with the WARC manager, a simple sampling instruction plan has been agreed on. The sampling via the RA will be performed 40 times within the period between April and October 2023. For each sampling, <2 hours will be needed for the preparation, sampling and processing. During the visit of the applicants in April, additional samples will be taken and processed at higher frequency. The research team will furthermore take samples for additional parameters such as dissolved and total nutrients. This period will also be used to check data quality and to collect control samples. For that, the team collect multiple samples, use different filter types and investigate the influence of sample storage time on results. All sampling material, consumables and the CTD device will be provided and shipped to WARC by AWI. The sampling material will be prepared as pre-packaged sets of color-coded bottles, syringes and filters. A post-field report and copies of all scientific contributions (scientific papers, maps, and databases) will be provided to the communities in the Inuvialuit Settlement Region through their Hunters and Trappers Committee (HTC) and through the Western Arctic Research Centre (WARC). The team plan to describe the proposed idea at a workshop in Inuvik and Aklavik on Feb 7-8, 2023, which gives a chance to listen to other scientists, community members and WARC staff for ways to improve the observations. The team will return in 2024 to present results at WARC and the Yellowknife Geoscience Forum. For public access, data will be made available via an interactive webpage similar to the one available for Lena River data (https://lena-monitoring.awi.de/). Whenever possible the team will arrange to make presentation at WARC in order to communicate the activities and results. The project is designed and planned in collaboration with the WARC within a proposal for the Interact Transnational and Virtual Access call. Paul Overduin presents the project during the Permafrost Workshop Week in Inuvik and Aklavik: Feb, 7th to 9th, 2023, to which the HTCs are invited. The water sampling on the East Channel within Inuvik is planned to be carried out by a local Environmental Monitor via the WARC and the HTC. The research team collaborates closely with Natural resource Canada to build a communication plan for the local community such as visiting school during subsequent sampling campaign. The fieldwork for this study will be conducted from May 5, 2023 to October 31, 2023.