Turbulent Fluxes at a Sub-Arctic Peatland and the Role of Data Processing Choices in Carbon Dynamics

Sub-Arctic peatlands are often delicately poised at the carbon source-sink threshold. With peatlands among the most carbon-dense ecosystems on Earth, they are critical players in global climate regulation, with land–atmosphere feedbacks that can disproportionately influence climate change trajectories. However, peatland carbon dynamics, and whether they act as sources or sinks for carbon, are strongly shaped by local conditions underscoring the need for site-specific measurements of turbulent fluxes and meteorology to predict their future role in the carbon cycle. While eddy-covariance is a common and critical in-situ measurement technique, the choice of pre-processing algorithms has the potential to interfere in the clear interpretation of source or sink classification in transitional peatland regimes .  

Here, we present two years of eddy-covariance observations from a newly established eddy-covariance tower in a fen peatland in northeastern Finland. Our analysis characterises the carbon dynamics at the site and addresses a key methodological challenge that is often overlooked: the uncertainty introduced by the subjective choices inherent in eddy-covariance data processing. By generating multiple datasets using alternative processing algorithms, we quantify the sensitivity of flux estimates at the peatland to these decisions, where processing methods affect conclusions regarding its source-sink status. The results provide motivation for a framework for more robust interpretation of peatland carbon fluxes.