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Reconcilable differences: a joint calibration of fine-root turnover times with radiocarbon and minirhizotrons


Ahrens, Bernhard; Hansson, Karna; Solly, Emily F; Schrumpf, Marion (2014). Reconcilable differences: a joint calibration of fine-root turnover times with radiocarbon and minirhizotrons. New Phytologist, 204(4):932-942.

Abstract

∙ We used bomb-radiocarbon and raw minirhizotron lifetimes of fine roots (< 0.5 mm indiameter) in the organic layer of Norway spruce (Picea abies) forests in southern Sweden totest if different models are able to reconcile the apparently contradicting turnover time esti-mates from both techniques.
∙ We present a framework based on survival functions that is able to jointly model bomb-radiocarbon and minirhizotron data. At the same time we integrate prior knowledge aboutbiases of both techniques – the classification of dead roots in minirhizotrons and the use ofcarbon reserves to grow new roots.
∙ Two-pool models, either in parallel or in serial setting, were able to reconcile the bomb-radiocarbon and minirhizotron data. These models yielded a mean residence time of 3.80 ± 0.16 yr (mean ± SD). On average 60 ± 2% of fine roots turned over within0.75 ± 0.10 yr, while the rest was turning over within 8.4 ± 0.2 yr. Bomb-radiocarbon andminirhizotron data alone give a biased estimate of fine-root turnover.
∙ The two-pool models allow a mechanistic interpretation for the coexistence of fast- andslow-cycling roots – suberization and branching for the serial-two-pool model and branchingdue to ectomycorrhizal fungi–root interactions for the parallel-two-pool model.

Abstract

∙ We used bomb-radiocarbon and raw minirhizotron lifetimes of fine roots (< 0.5 mm indiameter) in the organic layer of Norway spruce (Picea abies) forests in southern Sweden totest if different models are able to reconcile the apparently contradicting turnover time esti-mates from both techniques.
∙ We present a framework based on survival functions that is able to jointly model bomb-radiocarbon and minirhizotron data. At the same time we integrate prior knowledge aboutbiases of both techniques – the classification of dead roots in minirhizotrons and the use ofcarbon reserves to grow new roots.
∙ Two-pool models, either in parallel or in serial setting, were able to reconcile the bomb-radiocarbon and minirhizotron data. These models yielded a mean residence time of 3.80 ± 0.16 yr (mean ± SD). On average 60 ± 2% of fine roots turned over within0.75 ± 0.10 yr, while the rest was turning over within 8.4 ± 0.2 yr. Bomb-radiocarbon andminirhizotron data alone give a biased estimate of fine-root turnover.
∙ The two-pool models allow a mechanistic interpretation for the coexistence of fast- andslow-cycling roots – suberization and branching for the serial-two-pool model and branchingdue to ectomycorrhizal fungi–root interactions for the parallel-two-pool model.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Institute of Geography
Dewey Decimal Classification:910 Geography & travel
Language:English
Date:2014
Deposited On:22 Mar 2018 12:40
Last Modified:13 Apr 2018 11:43
Publisher:Wiley-Blackwell Publishing, Inc.
ISSN:0028-646X
OA Status:Closed
Free access at:Publisher DOI. An embargo period may apply.
Publisher DOI:https://doi.org/10.1111/nph.12979

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