Radiocarbon measurements of ecosystem respiration and soil pore-space CO2 in Utqiaġvik (Barrow), Alaska
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 radioca...
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ftcdlib:oai:escholarship.org:ark:/13030/qt8xq3k47z 2023-09-26T15:15:24+02:00 Radiocarbon measurements of ecosystem respiration and soil pore-space CO2 in Utqiaġvik (Barrow), Alaska Vaughn, Lydia JS Torn, Margaret S 1943 - 1957 2018-01-01 application/pdf https://escholarship.org/uc/item/8xq3k47z unknown eScholarship, University of California qt8xq3k47z https://escholarship.org/uc/item/8xq3k47z public Earth System Science Data, vol 10, iss 4 Atmospheric Sciences Geochemistry Physical Geography and Environmental Geoscience article 2018 ftcdlib 2023-08-28T18:03:24Z 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 UtqiaAïvik (Barrow), Alaska, during the summers of 2012, 2013, and 2014. We found that radiocarbon in ecosystem respiration (Δ;14CReco) 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. Radiocarbon data and associated CO2 flux and temperature data are stored in the data repository of the Next Generation Ecosystem Experiments (NGEE-Arctic) at http://dx.doi.org/10.5440/1364062 and https://doi.org/10.5440/1418853. Article in Journal/Newspaper Arctic Barrow permafrost Alaska University of California: eScholarship Arctic |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
unknown |
topic |
Atmospheric Sciences Geochemistry Physical Geography and Environmental Geoscience |
spellingShingle |
Atmospheric Sciences Geochemistry Physical Geography and Environmental Geoscience Vaughn, Lydia JS Torn, Margaret S Radiocarbon measurements of ecosystem respiration and soil pore-space CO2 in Utqiaġvik (Barrow), Alaska |
topic_facet |
Atmospheric Sciences Geochemistry Physical Geography and Environmental Geoscience |
description |
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 UtqiaAïvik (Barrow), Alaska, during the summers of 2012, 2013, and 2014. We found that radiocarbon in ecosystem respiration (Δ;14CReco) 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. Radiocarbon data and associated CO2 flux and temperature data are stored in the data repository of the Next Generation Ecosystem Experiments (NGEE-Arctic) at http://dx.doi.org/10.5440/1364062 and https://doi.org/10.5440/1418853. |
format |
Article in Journal/Newspaper |
author |
Vaughn, Lydia JS Torn, Margaret S |
author_facet |
Vaughn, Lydia JS Torn, Margaret S |
author_sort |
Vaughn, Lydia JS |
title |
Radiocarbon measurements of ecosystem respiration and soil pore-space CO2 in Utqiaġvik (Barrow), Alaska |
title_short |
Radiocarbon measurements of ecosystem respiration and soil pore-space CO2 in Utqiaġvik (Barrow), Alaska |
title_full |
Radiocarbon measurements of ecosystem respiration and soil pore-space CO2 in Utqiaġvik (Barrow), Alaska |
title_fullStr |
Radiocarbon measurements of ecosystem respiration and soil pore-space CO2 in Utqiaġvik (Barrow), Alaska |
title_full_unstemmed |
Radiocarbon measurements of ecosystem respiration and soil pore-space CO2 in Utqiaġvik (Barrow), Alaska |
title_sort |
radiocarbon measurements of ecosystem respiration and soil pore-space co2 in utqiaġvik (barrow), alaska |
publisher |
eScholarship, University of California |
publishDate |
2018 |
url |
https://escholarship.org/uc/item/8xq3k47z |
op_coverage |
1943 - 1957 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic Barrow permafrost Alaska |
genre_facet |
Arctic Barrow permafrost Alaska |
op_source |
Earth System Science Data, vol 10, iss 4 |
op_relation |
qt8xq3k47z https://escholarship.org/uc/item/8xq3k47z |
op_rights |
public |
_version_ |
1778136347825930240 |