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Research article2017Peer reviewedOpen access

Aquatic export of young dissolved and gaseous carbon from a pristine boreal fen: Implications for peat carbon stock stability

Campeau, Audrey; Bishop, Kevin; Billett, Michael F.; Garnett, Mark H.; Laudon, Hjalmar; Leach, Jason; Nilsson, Mats; Öquist, Mats; Wallin, Marcus

Abstract

The stability of northern peatland's carbon (C) store under changing climate is of major concern for the global C cycle. The aquatic export of C from boreal peatlands is recognized as both a critical pathway for the remobilization of peat C stocks as well as a major component of the net ecosystem C balance (NECB). Here, we present a full year characterization of radiocarbon content (C-14) of dissolved organic carbon (DOC), carbon dioxide (CO2), and methane (CH4) exported from a boreal peatland catchment coupled with C-14 characterization of the catchment's peat profile of the same C species. The age of aquatic C in runoff varied little throughout the year and appeared to be sustained by recently fixed C from the atmosphere (<60 years), despite stream DOC, CO2, and CH4 primarily being sourced from deep peat horizons (2-4 m) near the mire's outlet. In fact, the C-14 content of DOC, CO2, and CH4 across the entire peat profile was considerably enriched with postbomb C compared with the solid peat material. Overall, our results demonstrate little to no mobilization of ancient C stocks from this boreal peatland and a relatively large resilience of the source of aquatic C export to forecasted hydroclimatic changes.

Keywords

aquatic C export; carbon dioxide; dissolved organic carbon; methane; northern peatlands; radiocarbon dating

Published in

Global Change Biology
2017, Volume: 23, number: 12, pages: 5523-5536
Publisher: WILEY