Temporal patterns of greenhouse gas emissions from two small thermokarst lakes in Nunavik, Canada

Most estimates of emissions rely solely on daily measurements, which may bias annual flux calculations. In this study, we combined GHG flux measurements from two intensive summer campaigns with nearly two years of continuous temperature, oxygen, and conductivity profiling in two small (<200 m²) thermokarst lakes in Nunavik (56°33'28.8"N, 76°28'46.5"W), Canada.

One campaign occurred during a colder summer (0.7°C above the seasonal mean) and the other during a warmer one (2.6°C above the seasonal mean), with one lake being humic and sheltered and the other more transparent and wind-exposed. Average diffusive fluxes of CO₂ (22.1 ± 20.5 mmol m⁻² d⁻¹; mean ± standard deviation) and CH₄ (14.3 ± 14.2 mmol CO₂-eq m⁻² d⁻¹) were consistent with values reported for similar thermokarst lakes, while N₂O fluxes were negligible (–0.8 ± 1.3 mmol CO₂-eq m⁻² d⁻¹).