Effects of thermo-erosional disturbance on surface soil carbon and nitrogen dynamics in upland arctic tundra

Thaw of ice-rich permafrost soils on sloping terrain can trigger erosional disturbance events that displace large volumes of soil and sediment, kill and damage plants, and initiate secondary succession. We examined how retrogressive thaw slumps (RTS), a common form of thermo-erosional disturbance in...

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Bibliographic Details
Published in:Environmental Research Letters
Main Authors: Camila Pizano, Andrés F Barón, Edward A G Schuur, Kathryn G Crummer, Michelle C Mack
Format: Article in Journal/Newspaper
Language:English
Published: IOP Publishing 2014
Subjects:
Q
Ice
Online Access:https://doi.org/10.1088/1748-9326/9/7/075006
https://doaj.org/article/11792a5b9a70491d8569df0b8e2feca0
Description
Summary:Thaw of ice-rich permafrost soils on sloping terrain can trigger erosional disturbance events that displace large volumes of soil and sediment, kill and damage plants, and initiate secondary succession. We examined how retrogressive thaw slumps (RTS), a common form of thermo-erosional disturbance in arctic tundra, affected the local loss and re-accumulation of carbon (C) and nitrogen (N) pools in organic and surface mineral soil horizons of 18 slumps within six spatially independent sites in arctic Alaska. RTS displaced 3 kg C and 0.2 kg N per m ^2 from the soil organic horizon but did not alter pools of C and N in the top 15 cm of the mineral horizon. Surface soil C pools re-accumulated rapidly (32 ± 10 g C m ^−2 yr ^−1 ) through the first 60 years of succession, reaching levels similar to undisturbed tundra 40–64 years after disturbance. Average N re-accumulation rates (2.2 ± 1.1 g N m ^−2 yr ^−1 ) were much higher than expected from atmospheric deposition and biological N fixation. Finally, plant community dominance shifted from graminoids to tall deciduous shrubs, which are likely to promote higher primary productivity, biomass accumulation, and rates of nutrient cycling.