Abundant pre-industrial carbon detected in Canadian Arctic headwaters: Implications for the permafrost carbon feedback

J. F. Dean, Y. Van Der Velde, M. H. Garnett, K. J. Dinsmore, R. Baxter, J. S. Lessels, P. Smith, L. E. Street, J. A. Subke, D. Tetzlaff, I. Washbourne, P. A. Wookey, M. F. Billett

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

Mobilization of soil/sediment organic carbon into inland waters constitutes a substantial, but poorly-constrained, component of the global carbon cycle. Radiocarbon (14C) analysis has proven a valuable tool in tracing the sources and fate of mobilized carbon, but aquatic 14C studies in permafrost regions rarely detect 'old' carbon (assimilated from the atmosphere into plants and soil prior to AD1950). The emission of greenhouse gases derived from old carbon by aquatic systems may indicate that carbon sequestered prior to AD1950 is being destabilized, thus contributing to the 'permafrost carbon feedback' (PCF). Here, we measure directly the 14C content of aquatic CO2, alongside dissolved organic carbon, in headwater systems of the western Canadian Arctic - the first such concurrent measurements in the Arctic. Age distribution analysis indicates that the age of mobilized aquatic carbon increased significantly during the 2014 snow-free season as the active layer deepened. This increase in age was more pronounced in DOC, rising from 101-228 years before sampling date (a 120%-125% increase) compared to CO2, which rose from 92-151 years before sampling date (a 59%-63% increase). 'Pre-industrial' aged carbon (assimilated prior to ∼AD1750) comprised 15%-40% of the total aquatic carbon fluxes, demonstrating the prevalence of old carbon to Arctic headwaters. Although the presence of this old carbon is not necessarily indicative of a net positive PCF, we provide an approach and baseline data which can be used for future assessment of the PCF.

LanguageEnglish
Article number034024
Pages1-11
Number of pages11
JournalEnvironmental Research Letters
Volume13
Issue number3
DOIs
StatePublished - 27 Feb 2018

Fingerprint

Permafrost
headwater
permafrost
Carbon
Feedback
carbon
Carbon Cycle
Carbon Monoxide
Organic carbon
Soil
Sampling
active layer
Soils
sampling
Snow
carbon flux
carbon cycle
age structure
Age Distribution
dissolved organic carbon

Keywords

  • Arctic catchments
  • carbon dioxide CO
  • dissolved organic carbon DOC
  • inland waters
  • methane CH
  • radiocarbon 14

Cite this

Dean, J. F. ; Van Der Velde, Y. ; Garnett, M. H. ; Dinsmore, K. J. ; Baxter, R. ; Lessels, J. S. ; Smith, P. ; Street, L. E. ; Subke, J. A. ; Tetzlaff, D. ; Washbourne, I. ; Wookey, P. A. ; Billett, M. F./ Abundant pre-industrial carbon detected in Canadian Arctic headwaters : Implications for the permafrost carbon feedback. In: Environmental Research Letters. 2018 ; Vol. 13, No. 3. pp. 1-11
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abstract = "Mobilization of soil/sediment organic carbon into inland waters constitutes a substantial, but poorly-constrained, component of the global carbon cycle. Radiocarbon (14C) analysis has proven a valuable tool in tracing the sources and fate of mobilized carbon, but aquatic 14C studies in permafrost regions rarely detect 'old' carbon (assimilated from the atmosphere into plants and soil prior to AD1950). The emission of greenhouse gases derived from old carbon by aquatic systems may indicate that carbon sequestered prior to AD1950 is being destabilized, thus contributing to the 'permafrost carbon feedback' (PCF). Here, we measure directly the 14C content of aquatic CO2, alongside dissolved organic carbon, in headwater systems of the western Canadian Arctic - the first such concurrent measurements in the Arctic. Age distribution analysis indicates that the age of mobilized aquatic carbon increased significantly during the 2014 snow-free season as the active layer deepened. This increase in age was more pronounced in DOC, rising from 101-228 years before sampling date (a 120{\%}-125{\%} increase) compared to CO2, which rose from 92-151 years before sampling date (a 59{\%}-63{\%} increase). 'Pre-industrial' aged carbon (assimilated prior to ∼AD1750) comprised 15{\%}-40{\%} of the total aquatic carbon fluxes, demonstrating the prevalence of old carbon to Arctic headwaters. Although the presence of this old carbon is not necessarily indicative of a net positive PCF, we provide an approach and baseline data which can be used for future assessment of the PCF.",
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Dean, JF, Van Der Velde, Y, Garnett, MH, Dinsmore, KJ, Baxter, R, Lessels, JS, Smith, P, Street, LE, Subke, JA, Tetzlaff, D, Washbourne, I, Wookey, PA & Billett, MF 2018, 'Abundant pre-industrial carbon detected in Canadian Arctic headwaters: Implications for the permafrost carbon feedback' Environmental Research Letters, vol. 13, no. 3, 034024, pp. 1-11. DOI: 10.1088/1748-9326/aaa1fe

Abundant pre-industrial carbon detected in Canadian Arctic headwaters : Implications for the permafrost carbon feedback. / Dean, J. F.; Van Der Velde, Y.; Garnett, M. H.; Dinsmore, K. J.; Baxter, R.; Lessels, J. S.; Smith, P.; Street, L. E.; Subke, J. A.; Tetzlaff, D.; Washbourne, I.; Wookey, P. A.; Billett, M. F.

In: Environmental Research Letters, Vol. 13, No. 3, 034024, 27.02.2018, p. 1-11.

Research output: Contribution to JournalArticleAcademicpeer-review

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T1 - Abundant pre-industrial carbon detected in Canadian Arctic headwaters

T2 - Environmental Research Letters

AU - Dean,J. F.

AU - Van Der Velde,Y.

AU - Garnett,M. H.

AU - Dinsmore,K. J.

AU - Baxter,R.

AU - Lessels,J. S.

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AU - Street,L. E.

AU - Subke,J. A.

AU - Tetzlaff,D.

AU - Washbourne,I.

AU - Wookey,P. A.

AU - Billett,M. F.

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N2 - Mobilization of soil/sediment organic carbon into inland waters constitutes a substantial, but poorly-constrained, component of the global carbon cycle. Radiocarbon (14C) analysis has proven a valuable tool in tracing the sources and fate of mobilized carbon, but aquatic 14C studies in permafrost regions rarely detect 'old' carbon (assimilated from the atmosphere into plants and soil prior to AD1950). The emission of greenhouse gases derived from old carbon by aquatic systems may indicate that carbon sequestered prior to AD1950 is being destabilized, thus contributing to the 'permafrost carbon feedback' (PCF). Here, we measure directly the 14C content of aquatic CO2, alongside dissolved organic carbon, in headwater systems of the western Canadian Arctic - the first such concurrent measurements in the Arctic. Age distribution analysis indicates that the age of mobilized aquatic carbon increased significantly during the 2014 snow-free season as the active layer deepened. This increase in age was more pronounced in DOC, rising from 101-228 years before sampling date (a 120%-125% increase) compared to CO2, which rose from 92-151 years before sampling date (a 59%-63% increase). 'Pre-industrial' aged carbon (assimilated prior to ∼AD1750) comprised 15%-40% of the total aquatic carbon fluxes, demonstrating the prevalence of old carbon to Arctic headwaters. Although the presence of this old carbon is not necessarily indicative of a net positive PCF, we provide an approach and baseline data which can be used for future assessment of the PCF.

AB - Mobilization of soil/sediment organic carbon into inland waters constitutes a substantial, but poorly-constrained, component of the global carbon cycle. Radiocarbon (14C) analysis has proven a valuable tool in tracing the sources and fate of mobilized carbon, but aquatic 14C studies in permafrost regions rarely detect 'old' carbon (assimilated from the atmosphere into plants and soil prior to AD1950). The emission of greenhouse gases derived from old carbon by aquatic systems may indicate that carbon sequestered prior to AD1950 is being destabilized, thus contributing to the 'permafrost carbon feedback' (PCF). Here, we measure directly the 14C content of aquatic CO2, alongside dissolved organic carbon, in headwater systems of the western Canadian Arctic - the first such concurrent measurements in the Arctic. Age distribution analysis indicates that the age of mobilized aquatic carbon increased significantly during the 2014 snow-free season as the active layer deepened. This increase in age was more pronounced in DOC, rising from 101-228 years before sampling date (a 120%-125% increase) compared to CO2, which rose from 92-151 years before sampling date (a 59%-63% increase). 'Pre-industrial' aged carbon (assimilated prior to ∼AD1750) comprised 15%-40% of the total aquatic carbon fluxes, demonstrating the prevalence of old carbon to Arctic headwaters. Although the presence of this old carbon is not necessarily indicative of a net positive PCF, we provide an approach and baseline data which can be used for future assessment of the PCF.

KW - Arctic catchments

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KW - dissolved organic carbon DOC

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KW - methane CH

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