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Title: Radiocarbon measurements of ecosystem respiration and soil pore-space CO 2 in Utqiagvik (Barrow), Alaska

Abstract

Radiocarbon measurements of ecosystem respiration and soil pore space CO 2 are useful for determining the sources of ecosystem respiration,identifying environmental controls on soil carbon cycling rates, and parameterizing and evaluating models of the carbon cycle. We measured flux rates and radiocarbon content of ecosystem respiration, as well as radiocarbon in soil profile CO 2 in Utqiagvik (Barrow), Alaska, during the summers of 2012, 2013, and 2014.We found that radiocarbon in ecosystem respiration(Δ 14C Reco) ranged from +60.5 to –160‰ with a median value of +23.3‰. Ecosystem respiration became more depleted in radiocarbon from summer to autumn, indicating increased decomposition of old soil organic carbon and/or decreased CO 2 production from fast-cycling carbon pools. Across permafrost features,ecosystem respiration from high-centered polygons was depleted in radiocarbon relative to other polygon types. Radiocarbon content in soil pore-space CO 2 varied between –7.1 and –280‰, becoming more negative with depth in individual soil profiles. These pore-space radiocarbon values correspond to CO 2 mean ages of 410 to 3350 years, based on a steady-state, one-pool model. Together, these data indicate that deep soil respiration was derived primarily from old, slow-cycling carbon, but that total CO 2 fluxes depended largely on autotrophic respiration and heterotrophic decompositionmore » of fast-cycling carbon within the shallowest soil layers. The relative contributions of these different CO 2 sources were highly variable across microtopographic features and time in the sampling season. The highly negative Δ 14C values in soil pore-space CO 2 and autumn ecosystem respiration indicate that when it is not frozen, very old soil carbon is vulnerable to decomposition.« less

Authors:
 [1];  [2]
  1. Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States)
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
OSTI Identifier:
1563968
Grant/Contract Number:  
AC02-05CH11231
Resource Type:
Accepted Manuscript
Journal Name:
Earth System Science Data (Online)
Additional Journal Information:
Journal Name: Earth System Science Data (Online); Journal Volume: 10; Journal Issue: 4; Journal ID: ISSN 1866-3516
Publisher:
Copernicus
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES

Citation Formats

Vaughn, Lydia J. S., and Torn, Margaret S. Radiocarbon measurements of ecosystem respiration and soil pore-space CO2 in Utqiagvik (Barrow), Alaska. United States: N. p., 2018. Web. doi:10.5194/essd-10-1943-2018.
Vaughn, Lydia J. S., & Torn, Margaret S. Radiocarbon measurements of ecosystem respiration and soil pore-space CO2 in Utqiagvik (Barrow), Alaska. United States. doi:10.5194/essd-10-1943-2018.
Vaughn, Lydia J. S., and Torn, Margaret S. Mon . "Radiocarbon measurements of ecosystem respiration and soil pore-space CO2 in Utqiagvik (Barrow), Alaska". United States. doi:10.5194/essd-10-1943-2018. https://www.osti.gov/servlets/purl/1563968.
@article{osti_1563968,
title = {Radiocarbon measurements of ecosystem respiration and soil pore-space CO2 in Utqiagvik (Barrow), Alaska},
author = {Vaughn, Lydia J. S. and Torn, Margaret S.},
abstractNote = {Radiocarbon measurements of ecosystem respiration and soil pore space CO2 are useful for determining the sources of ecosystem respiration,identifying environmental controls on soil carbon cycling rates, and parameterizing and evaluating models of the carbon cycle. We measured flux rates and radiocarbon content of ecosystem respiration, as well as radiocarbon in soil profile CO2 in Utqiagvik (Barrow), Alaska, during the summers of 2012, 2013, and 2014.We found that radiocarbon in ecosystem respiration(Δ14CReco) ranged from +60.5 to –160‰ with a median value of +23.3‰. Ecosystem respiration became more depleted in radiocarbon from summer to autumn, indicating increased decomposition of old soil organic carbon and/or decreased CO2 production from fast-cycling carbon pools. Across permafrost features,ecosystem respiration from high-centered polygons was depleted in radiocarbon relative to other polygon types. Radiocarbon content in soil pore-space CO2 varied between –7.1 and –280‰, becoming more negative with depth in individual soil profiles. These pore-space radiocarbon values correspond to CO2 mean ages of 410 to 3350 years, based on a steady-state, one-pool model. Together, these data indicate that deep soil respiration was derived primarily from old, slow-cycling carbon, but that total CO2 fluxes depended largely on autotrophic respiration and heterotrophic decomposition of fast-cycling carbon within the shallowest soil layers. The relative contributions of these different CO2 sources were highly variable across microtopographic features and time in the sampling season. The highly negative Δ14C values in soil pore-space CO2 and autumn ecosystem respiration indicate that when it is not frozen, very old soil carbon is vulnerable to decomposition.},
doi = {10.5194/essd-10-1943-2018},
journal = {Earth System Science Data (Online)},
number = 4,
volume = 10,
place = {United States},
year = {2018},
month = {10}
}

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