Characteristics of Carbon Fluxes for Tundra Ecosystems Adjacent to a Pond in Arctic Canada

The Arctic permafrost is a large carbon pool that is highly sensitive to climate change. Carbon fluxes were examined to understand the characteristics of the carbon cycle in tundra ecosystems adjacent to a pond. Freshwater lakes (large-scale) and ponds (small-scale) within the Arctic terrestrial ecosystem play important biogeochemical roles and, in some cases, are major sources of greenhouse gas emissions. Globally, lakes are primarily distributed in Canada and Russia, accounting for 42% and 49% of the total, respectively. The study site is located on dry tundra with a pond in the High Arctic near Cambridge Bay, Nunavut, Canada (69°7′47.7″N, 105°3′35.3″W). CO₂ and CH₄ fluxes were measured in the tundra ecosystem to evaluate the potential future sensitivity of the carbon cycle to climate change during the summers of 2019, 2022, and 2025. The vegetation cover around the site mainly consists of dwarf shrubs, graminoids, and lichens. Carbon fluxes were compared under different soil water content conditions. Based on the chamber measurements, the variability of net CO₂ exchange was more sensitive in grasses under wet conditions than in vegetation under dry conditions, and both the variability and magnitude of CH₄ emissions near ponds were greater than those under dry conditions. CO₂ and CH₄ fluxes showed a positive relationship in nearly bare soil under wet conditions and a negative relationship in areas with various vegetation under dry conditions. Net ecosystem exchange, ecosystem respiration, and gross primary production were estimated using two types of chambers to investigate the influence of carbon dynamics on the tundra carbon cycle. Carbon fluxes were compared across three years during the snow-free season, and the controlling factors of the carbon cycle were examined. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (RS-2025-24683148).