Arctic freshwater carbon dynamics

Lead: Judith Vogt

Arctic freshwater carbon dynamics

Freshwater ecosystems such as lakes and rivers emit large quantities of carbon dioxide and methane to the atmosphere on a global level [1,2]. For Arctic regions, especially where permafrost is present and thawing is accelerating due to global warming, emissions from existing and newly forming water bodies may alter feedback processes with climate [3]. However, the drivers of freshwater carbon emissions remain largely unknown, and flux estimates come with high uncertainties due to scarcity of 1) comprehensive observational data from northern regions, and 2) representation of heterogeneous processes in a quickly transitioning Arctic.

To advance our understanding of carbon fluxes between the water surface and the atmosphere, we synthesized existing observational data from spatially distributed chamber measurements, eddy covariance time series of carbon dioxide and methane, and other flux techniques as well as water chemistry and site characteristics within the Arctic-boreal region. The synthesized data is published within ABCFlux v2: Arctic–boreal CO₂ and CH₄ monthly flux observations and ancillary information across terrestrial and freshwater ecosystems.

While we wish to inform high-resolution process modelers about carbon flux drivers in the Arctic, we hope the dataset will be useful to a wide range of users. As a next step, we aim to upscale the synthesized data to a pan-Arctic level and update the data-driven estimate of freshwater contributions to the Arctic carbon budget. This work contributes to the projects Q-ARCTIC and GreenFeedBack. If you would like to learn more, please contact us.

To fill existing gaps in data coverage and to actively contribute to the pan-Arctic synthesis, we conduct further field campaigns and collect measurements with floating chambers on lakes and rivers.

In August 2023, we focused on a natural river system in northern Fennoscandia to determine the carbon budget of the fast-flowing river Teno (Norwegian: Tana, Northern Sami: Deatnu). We measured carbon fluxes with a floating chamber from the shore and from a small boat while drifting downstream, and obtained hydrochemical parameters of the water surface. Based on these measurements, we determined very small vertical exchange of carbon dioxide and methane between the river and the atmosphere.

In summer 2024, we measured carbon fluxes on various lake shores in Inuvik, Canada. With these measurements, we determined spatial differences of lake emissions within the study region. Another field campaign with a focus on lakes in the Stordalen mire was conducted in 2025 with a new autonomous measurement platform to capture and advance our understanding of small scale spatial flux variability.

 

References

1. Raymond, P., Hartmann, J., Lauerwald, R. et al. Global carbon dioxide emissions from inland waters. Nature 503, 355–359 (2013). Global carbon dioxide emissions from inland waters | Nature
2. Rosentreter, J.A., Borges, A.V., Deemer, B.R. et al. Half of global methane emissions come from highly variable aquatic ecosystem sources. Nat. Geosci. 14, 225–230 (2021). Half of global methane emissions come from highly variable aquatic ecosystem sources | Nature Geoscience
3. Miner, K.R., Turetsky, M.R., Malina, E. et al. Permafrost carbon emissions in a changing Arctic. Nat Rev Earth Environ 3, 55–67 (2022). https://doi.org/10.1038/s43017-021-00230-3