NWT RESEARCH DATABASE

Regions: Inuvialuit Settlement Region

Objective(s): To monitor atmospheric and surface water concentrations of CH4 and CO2 and their stable carbon isotopes (d13C). To measure surface water temperature, salinity, and dissolved oxygen. These data will be used to assess the role of the North-West passage in CO2 uptake and CH4 emissions.

Project Description: This licence has been issued for the scientific research application No. 5937. Arctic Change: The project supervised by UNIGE, Geneva University and conducted onboard by Marion Cherrak, Science Lead at Pacifique, will continuously monitor environmental data: greenhouse gasses (carbon dioxide and methane) and standard oceanographic parameters in surface water/water column and the polar atmosphere. The Arctic plays a crucial role in the global cycle of the main carbon-based greenhouse gases, methane (CH4) and carbon dioxide (CO2). The study carried out here aims to measure and quantify the fluxes of CO2 and CH4 between the Arctic Ocean and atmosphere, as well as the distribution of their stable isotopes of carbon (d13C), between the Arctic Ocean and the atmosphere. It is known that high-latitude seas are important CO2 sinks. In contrast, the Arctic is, to a lesser extent, a source of methane with a warming potential greater than CO2. GHG flows are, and will be, impacted by current environmental changes. It is crucial to determine whether the Arctic's role in mitigating global warming will be compromised. This study will improve our understanding of the contribution of the polar regions to global climate change. This is the 4th year of the Changing Arctic expedition collecting these data to compile a GHG data base, and to assess the fluxes of these GHGs. Thus, the short-term and long-term goals are: • To monitor atmospheric and surface water concentrations of CH4 and CO2 and their stable carbon isotopes (d13C). To measure surface water temperature, salinity, and dissolved oxygen. These data will be used to assess the role of the North-West passage in CO2 uptake and CH4 emissions. • The longer-term adjectives are to provide additional data in the Arctic region to add to the CO2 and CH4 budgets for the region, as well as temperature data. The atmospheric GHG concentrations are measured in real-time from a Portable Greenhouse Gas Analyzer of Los Gatos Research (LGR). This instrument measure the CO2, CH4, and H2O gases in ppm. The machine constantly draws in air at the top of the sailboat mast, which passes through a chamber with two mirrors where lasers move back and forth between them with a certain wavelength. A multiparameter probe (CTD) is installed in the hull of the sailboat and measures every minute the temperature [°C], conductivity [µs/cm], TDS total dissolved solids [mg/l], turbidity [FNU], salinity [PSU], optical dissolved oxygen [% sat], TSS [mg/l], pressure [bar] and depth [m]. The CTD is positioned just below the surface so that it can always remain in the water, even during navigation. Manual sampling is performed to quantify CO2 and CH4 concentrations in the surface water. The sampling is done using the “headspace” method which equilibrates the gas molecules in the aqueous phase and those in the gaseous phase. To be realized, the headspace requires a 12 ml tube (exetainer), a syringe of 140 ml, a syringe of 30 ml, a needle, and a three-way stopcock. Water is drawn into the 140 ml syringe, then the bubbles are removed along with 35 ml of water to create a headspace which is filled with uncontaminated atmospheric air. The syringe is shaken for at least two minutes which brings the gas to water-air equilibrium. Finally, the gas is transferred to a pre-evacuated 12mL exetainer. These samples are shipped to University of Geneva and analyzed in the laboratory with the Picarro stable isotope analyzer (CH4 and CO2). Two other small participatory science projects are planned: -Opportunistic sampling of surface debris (microplastics) along the way for non-profit Oceaneye (www.oceaneye.ch). The data on the microplastics sampled are then uploaded into UNEP Environmental Database (https://wesr.unep.org/topic/globalmonitoring) -Opportunisticsamplingofplankton(https://www.planktoscope.org)alongthewayusinga PlanktoScope. The Planktoscope is a machine that quantitatively photographs plankton to analyze and count the plankton population at different locations. These photos are then sent to the EcoTaxa website (https://ecotaxa.obs-vlfr.fr), which uses artificial intelligence to identify plankton. Data will be stored per Swiss National Science Foundation recommendations. These data will be stored on the Yareta server at the University of Geneva. Additionally, data can be viewed at https://arctic- change.herokuapp.com/. This website contains data collected since the project saturate in 2020. We also provide a scientific report at the end of the year and up to date information are available on our website www.pacifique.ch and instagram. The fieldwork for this study will be conducted from: July 10 - July 30, 2024