NWT RESEARCH DATABASE

Tags: physical sciences, climate change, hydrology, organic matter, carbon fluxes, biogeochemical processes, carbon, sediment core sampling, groundwater discharge

Objective(s): To document trends in export of coastal, riverine and subterranean dissolved and particulate organic matter and carbon into the Arctic Ocean; to determine their fate and related processes in coastal waters and estuarine sediment; and to assess the impacts of these findings on the biogeochemical processes of coastal waters as well as their impact on global carbon dioxide fluxes.

Project Description: The specific objectives of this project are: 1) to document trends in export of coastal, riverine and subterranean dissolved and particulate organic matter and carbon into the Arctic Ocean; 2) to determine their fate and related processes (origin and age, transport, physical, chemical, and biological transformation) in coastal waters and estuarine sediment; and 3) to assess the impacts of these findings on the biogeochemical processes of coastal waters as well as their impact on global carbon dioxide fluxes. Considering that the quality and the origin of organic matter (e.g., ages, origins and molecular structures) varies seasonally, different months will be targeted: May, June, July, August and September. This will cover the periods before, during and after the ice bridge (stamukhi) breaks up at the mouth of the two main coastal channels of the delta. The field observations will document the seasonal variations in the chemical and optical properties of the coastal and riverine end-members of terrigenous organic matter (OMt) as well as coastal groundwaters and subterranean flows in MacKenzie delta. Several optical sensors on one frame will be deployed at once at the station to assess the biogeochemical and the bio-optical properties of the delta and coastal waters (e.g., backscattering, fluorescence of chlorophyll a and colored dissolved organic matter, particle size, CTD and radiance sensors). The optical frame will be profiling from top to bottom in less than 50m water, therefore it will be for less than 20 min in water at each profile. In addition to optical properties of bulk OMt obtained in situ sensors, detailed chemical characteristics of OMt and carbonate system will be determined on discrete water samples, including information on age and composition of OMt (dissolved and particulate carbon content and absorption, pigments, particulate suspended matter, nutrients, bacterial abundance and diversity, carbon age and origin, biomarkers, lignin, partial pressure in carbon dioxide). In May and August, the research team will also sample 3 surface sediment core (50 cm) per sites for analysis of total elemental concentrations, biomarkers, reactive iron and sulfur, lead-210 dating, and retrieval of porewater samples. In addition, in July and August, isotopes will be measured from a coastal site in Tuktoyaktuk at different sites along the aquatic continuum to detect and quantify groundwater discharge. This will be measured from freshly dug pits and temporary polyvinyl chloride well points inserted in the ground on the shoreline for periods of 15 days each month. The project is planning on training 1 field assistant on optical measurement analysis in a laboratory and 1 field assistant for groundwater study sampling at a coastal station in Tuktoyaktuk. Training will be covering scientific development and technical skills in the context of a climate change fundamental study. The research field assistance project will provide the participants with excellent networking opportunities with various government agencies (Department of Fisheries and Oceans, Natural Research Canada), the academic sector at national and international levels (universities, HQP) and regional authorities (Hamlets, Intergovernmental Council) that are part of the project. This will allow them to develop their communication skills and exchange with potential employers and research collaborators, participate in knowledge exchange, and to present their results to the northern communities mentored by the team, if they are interested. This training opportunity will provide hands-on learning science-leading tools and technique that will help Inuvialuit build first nation science skilled models. These models will encourage youth to be involved in science at different levels. The training will enhance the education experience of the field assistant so that it can then be translated by the Inuvialuit model to other students in school. As the research team is planning on participating in the ARI youth program by providing a science presentation in the school in May and June, such Inuvialuit model will inspire and build confidence in Inuvialuit, particularly youth, to pursue education and careers within academia, cultural skill development, and science-based careers. In addition, the research team are working to develop a strong collaboration with Tuktoyaktuk Community Corporation in science capacity building through a 3 years funded Climate Change Monitoring program. The proposed project would be to track changes in hydrogeochemistry (temperature, salinity and pH) of the coastal groundwater. The training of the trainees would take place in 2019 during the Nunataryuk WP4 field season at the coastal station. The team will use the infrastructure (piezometers, in-situ multiparametric probes, water level loggers) already used in the project to facilitate and mobilise knowledge exchanges through climate change issues and implication water quality and saltwater intrusion. The highly qualified trainers would provide skills to properly sample the groundwater, to use and calibrate scientific equipment, to analyse the data and to present them at different scales. The team hopes this will contribute towards inclusive climate change adaptation and interventions. In March 2018, the project was presented to the Inuvialuit Game Council (IGC) which included 7 Hunter and Trapper committee representatives, and the IGC coordinator. The research team benefited from participating in the NRCan outreach activities in the school classrooms in Inuvik and Tuktoyaktuk, and used that opportunity to present the planned 2019 activities to the teachers and their intention to visit their classrooms for knowledge exchange. In May 2019, the team will do a public presentation of the project to the Inuvik community and the same to the Tuktoyaktuk community in July. This is to ensure local community members are aware of the objectives and scheduled operations of the project before local activities starts. The team are planning to participate in the ARI youth program by presenting school activities in Inuvik and Tuktoyaktuk. Communication may range from simple reporting of results to collaborative, reciprocal knowledge-sharing. It will include: meetings, presentations in the community and schools, written field reports, copies of publications or theses, co-authored publications and interactive multi-media websites. In addition, the project findings will contribute to the Integrated Regional Impact Studies for the Western Arctic Region. The fieldwork for this study will be conducted from May 15, 2019 to September 30, 2019.