Street, Lorna E, Garnett, Mark H, Subke, Jens-Arne, Baxter, Robert, Dean, Joshua F 
ORCID: 0000-0001-9058-7076 and Wookey, Philip A
(2020)
Plant carbon allocation drives turnover of old soil organic matter in permafrost tundra soils.
GLOBAL CHANGE BIOLOGY, 26 (8).
pp. 4559-4571.
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2020 Street et al, GCB - Plant carbon allocation and old soil organic matter in permafrost.pdf - Published version Download (1MB) | Preview |
Abstract
<jats:title>Abstract</jats:title><jats:p>Carbon cycle feedbacks from permafrost ecosystems are expected to accelerate global climate change. Shifts in vegetation productivity and composition in permafrost regions could influence soil organic carbon (SOC) turnover rates via rhizosphere (root zone) priming effects (RPEs), but these processes are not currently accounted for in model predictions. We use a radiocarbon (bomb‐<jats:sup>14</jats:sup>C) approach to test for RPEs in two Arctic tall shrubs, alder (<jats:italic>Alnus viridis</jats:italic> (Chaix) DC.) and birch (<jats:italic>Betula glandulosa</jats:italic> Michx.), and in ericaceous heath tundra vegetation. We compare surface CO<jats:sub>2</jats:sub> efflux rates and <jats:sup>14</jats:sup>C content between intact vegetation and plots in which below‐ground allocation of recent photosynthate was prevented by trenching and removal of above‐ground biomass. We show, for the first time, that recent photosynthate drives mineralization of older (>50 years old) SOC under birch shrubs and ericaceous heath tundra. By contrast, we find no evidence of RPEs in soils under alder. This is the first direct evidence from permafrost systems that vegetation influences SOC turnover through below‐ground C allocation. The vulnerability of SOC to decomposition in permafrost systems may therefore be directly linked to vegetation change, such that expansion of birch shrubs across the Arctic could increase decomposition of older SOC. Our results suggest that carbon cycle models that do not include RPEs risk underestimating the carbon cycle feedbacks associated with changing conditions in tundra regions.</jats:p>
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | arctic, below-ground, isotopes, mycorrhiza, priming, radiocarbon, rhizosphere, root, shrub, vegetation change |
| Divisions: | Faculty of Science and Engineering > School of Environmental Sciences |
| Depositing User: | Symplectic Admin |
| Date Deposited: | 19 May 2021 08:24 |
| Last Modified: | 04 Sep 2023 20:00 |
| DOI: | 10.1111/gcb.15134 |
| Open Access URL: | https://doi.org/10.1111/gcb.15134 |
| Related URLs: | |
| URI: | https://livrepository.liverpool.ac.uk/id/eprint/3123182 |
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