Aged soils contribute little to contemporary carbon cycling downstream of thawing permafrost peatlands. ...

Vast stores of millennial-aged soil carbon (MSC) in permafrost peatlands risk leaching into the contemporary carbon cycle after thaw caused by climate warming or increased wildfire activity. Here we tracked the export and downstream fate of MSC from two peatland-dominated catchments in subarctic Can...

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Bibliographic Details
Main Authors: Tanentzap, Andrew J, Burd, Katheryn, Kuhn, McKenzie, Estop-Aragonés, Cristian, Tank, Suzanne E, Olefeldt, David
Format: Article in Journal/Newspaper
Language:English
Published: Wiley 2021
Subjects:
boreal
carbon cycling
disturbance
food webs
permafrost peatlands
streams
terrestrial-aquatic linkages
Carbon
Carbon Cycle
Ecosystem
Permafrost
Soil
Canada
permafrost
Subarctic
Thermokarst
Online Access:https://dx.doi.org/10.17863/cam.71218
https://www.repository.cam.ac.uk/handle/1810/323760
Description
Summary:Vast stores of millennial-aged soil carbon (MSC) in permafrost peatlands risk leaching into the contemporary carbon cycle after thaw caused by climate warming or increased wildfire activity. Here we tracked the export and downstream fate of MSC from two peatland-dominated catchments in subarctic Canada, one of which was recently affected by wildfire. We tested whether thermokarst bog expansion and deepening of seasonally thawed soils due to wildfire increased the contributions of MSC to downstream waters. Despite being available for lateral transport, MSC accounted for ≤6% of dissolved organic carbon (DOC) pools at catchment outlets. Assimilation of MSC into the aquatic food web could not explain its absence at the outlets. Using δ13 C-Δ14 C-δ15 N-δ2 H measurements, we estimated only 7% of consumer biomass came from MSC by direct assimilation and algal recycling of heterotrophic respiration. Recent wildfire that caused seasonally thawed soils to reach twice as deep in one catchment did not change these ...

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