Current forest carbon fixation fuels stream CO2 emissions

Autor: Michael F. Billett, Mats G. Öquist, Nino Amvrosiadi, Mark H. Garnett, Marcus B. Wallin, Audrey Campeau, Hjalmar Laudon, Kevin Bishop
Jazyk: angličtina
Rok vydání: 2019
Předmět:
Zdroj: Nature Communications, Vol 10, Iss 1, Pp 1-9 (2019)
Nature Communications
ISSN: 2041-1723
Popis: Stream CO2 emissions contribute significantly to atmospheric climate forcing. While there are strong indications that groundwater inputs sustain these emissions, the specific biogeochemical pathways and timescales involved in this lateral CO2 export are still obscure. Here, via an extensive radiocarbon (14C) characterisation of CO2 and DOC in stream water and its groundwater sources in an old-growth boreal forest, we demonstrate that the 14C-CO2 is consistently in tune with the current atmospheric 14C-CO2 level and shows little association with the 14C-DOC in the same waters. Our findings thus indicate that stream CO2 emissions act as a shortcut that returns CO2 recently fixed by the forest vegetation to the atmosphere. Our results expose a positive feedback mechanism within the C budget of forested catchments, where stream CO2 emissions will be highly sensitive to changes in forest C allocation patterns associated with climate and land-use changes.
There is a growing consensus that groundwater inflow supplies most of the C load to streams, but the sources and timescales generating this flux are still unknown. Here, the authors demonstrate that soil respiration, derived from current forest carbon fixation, fuels stream CO2 emissions.
Databáze: OpenAIRE