Northern forests are important ecosystems for carbon (C) cycling and lakes within them process and bury large amounts of organic-C. Current burial estimates are poorly constrained and may discount other shifts in organic-C burial driven by global change. Here we analyse a suite of northern lakes to determine trends in organic-C burial throughout the Anthropocene. We found burial rates increased significantly over the last century and are up to five times greater than previous estimates. Despite a correlation with temperature, warming alone did not explain the increase in burial, suggesting the importance of other drivers including atmospherically deposited reactive nitrogen. Upscaling mean lake burial rates for each time period to global northern forests yields up to 4.5 Pg C accumulated in the last 100 years - 20% of the total burial over the Holocene. Our results indicate that lakes will become increasingly important for C burial under future global change scenarios.
Bibliographical noteFunding Information:
We thank Kathleen Laird, Derek Muir and Marie-Eve Ferland for sharing previously published sediment core data. This project was part of the large-scale research programme of the Industrial Research Chair in Carbon Biogeochemistry in Boreal Aquatic Systems (CarBBAS), co-funded by the Natural Sciences and Engineering Research Council of Canada (NSERC) and Hydro-Québec to PdG, and also supported by NSERC funding to Y.T.P., N.J.A. acknowledges the support of a Royal Society (London) Wolfson Merit award.