Release of aquatic carbon from two peatland catchments in E. Finland during the spring snowmelt period

• Published in: Biogeochemistry
• Main Authors: Dyson, Kirstie E., Billett, Michael F., Dinsmore, Kerry J., Harvey, Frank, Thomson, Amanda M., Piirainen, Sirpa, Kortelainen, Pirkko
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Springer 2011
• Subjects: Ecology and Environment; Hydrology; Arctic
• Online Access: http://nora.nerc.ac.uk/id/eprint/13635/; https://doi.org/10.1007/s10533-010-9452-3

Spring snowmelt in the arctic and boreal regions represents the most significant event in the hydrological year. We measured concentrations and fluxes of different carbon species in 2 small contrasting (control v drained) forested peatland catchments in E. Finland between April and June 2008 and compared these to long-term annual fluxes. Measurements were made using a combination of continuous sensors (CO2, temperature, pH, discharge) and routine spot sampling (DOC, POC, DIC, CO2, CH4, N2O). The highest concentrations of CO2 and CH4 in streamwater were observed under low flow conditions before the spring flood event,reflecting accumulation and downstream release of gaseous C at the end of the winter period. Over the length of the study mean CH4 concentrations were 10x higher in the drained site. The snowmelt event was associated with a dilution of DOC and CO2, with the drained catchment showing a much flashier hydrological response compared to the control site, and post-event, a slower recovery in DOC and CO2 concentrations. Fluxes of all carbon species during the snowmelt event were significant and represented 37–45% of the annual flux. This highlights the challenge of quantifying aquatic C fluxes in areas with large temporal variability and suggests that inability to ‘‘capture’’ the spring snowmelt event may lead to under-estimation of C fluxes in northern regions.