Decomposition of old organic matter as a result of deeper active layers in a snow depth manipulation experiment.
A snow addition experiment in moist acidic tussock tundra at Toolik Lake, Alaska, increased winter snow depths 2-3 m, and resulted in a doubling of the summer active layer depth. We used radiocarbon (Delta(14)C) to (1) determine the age of C respired in the deep soils under control and deepened acti...
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Language: | English |
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ftcdlib:qt7mh9w489 2023-05-15T15:01:57+02:00 Decomposition of old organic matter as a result of deeper active layers in a snow depth manipulation experiment. Nowinski, NS Taneva, L Trumbore, SE Welker, JM 785 - 792 2010-07-01 application/pdf http://www.escholarship.org/uc/item/7mh9w489 english eng eScholarship, University of California qt7mh9w489 http://www.escholarship.org/uc/item/7mh9w489 public Nowinski, NS; Taneva, L; Trumbore, SE; & Welker, JM. (2010). Decomposition of old organic matter as a result of deeper active layers in a snow depth manipulation experiment. Oecologia, 163(3), 785 - 792. doi:10.1007/s00442-009-1556-x. UC Irvine: Retrieved from: http://www.escholarship.org/uc/item/7mh9w489 Carbon Dioxide Carbon Carbon Isotopes Organic Chemicals Soil Snow Fresh Water Environmental Monitoring Time Factors Alaska Arctic Regions Heterotrophic Processes Autotrophic Processes article 2010 ftcdlib https://doi.org/10.1007/s00442-009-1556-x 2018-07-20T22:51:17Z A snow addition experiment in moist acidic tussock tundra at Toolik Lake, Alaska, increased winter snow depths 2-3 m, and resulted in a doubling of the summer active layer depth. We used radiocarbon (Delta(14)C) to (1) determine the age of C respired in the deep soils under control and deepened active layer conditions (deep snow drifts), and (2) to determine the impact of increased snow and permafrost thawing on surface CO(2) efflux by partitioning respiration into autotrophic and heterotrophic components. Delta(14)C signatures of surface respiration were higher in the deep snow areas, reflecting a decrease in the proportion of autotrophic respiration. The radiocarbon age of soil pore CO(2) sampled near the maximum mid-July thaw depth was approximately 1,000 years in deep snow treatment plots (45-55 cm thaw depth), while CO(2) from the ambient snow areas was approximately 100 years old (30-cm thaw depth). Heterotrophic respiration Delta(14)C signatures from incubations were similar between the two snow depths for the organic horizon and were extremely variable in the mineral horizon, resulting in no significant differences between treatments in either month. Radiocarbon ages of heterotrophically respired C ranged from <50 to 235 years BP in July mineral soil samples and from 1,525 to 8,300 years BP in August samples, suggesting that old soil C in permafrost soils may be metabolized upon thawing. In the surface fluxes, this old C signal is obscured by the organic horizon fluxes, which are significantly higher. Our results indicate that, as permafrost in tussock tundra ecosystems of arctic Alaska thaws, carbon buried up to several thousands of years ago will become an active component of the carbon cycle, potentially accelerating the rise of CO(2) in the atmosphere. Article in Journal/Newspaper Arctic permafrost Tundra Alaska University of California: eScholarship Arctic Oecologia 163 3 785 792 |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
English |
topic |
Carbon Dioxide Carbon Carbon Isotopes Organic Chemicals Soil Snow Fresh Water Environmental Monitoring Time Factors Alaska Arctic Regions Heterotrophic Processes Autotrophic Processes |
spellingShingle |
Carbon Dioxide Carbon Carbon Isotopes Organic Chemicals Soil Snow Fresh Water Environmental Monitoring Time Factors Alaska Arctic Regions Heterotrophic Processes Autotrophic Processes Nowinski, NS Taneva, L Trumbore, SE Welker, JM Decomposition of old organic matter as a result of deeper active layers in a snow depth manipulation experiment. |
topic_facet |
Carbon Dioxide Carbon Carbon Isotopes Organic Chemicals Soil Snow Fresh Water Environmental Monitoring Time Factors Alaska Arctic Regions Heterotrophic Processes Autotrophic Processes |
description |
A snow addition experiment in moist acidic tussock tundra at Toolik Lake, Alaska, increased winter snow depths 2-3 m, and resulted in a doubling of the summer active layer depth. We used radiocarbon (Delta(14)C) to (1) determine the age of C respired in the deep soils under control and deepened active layer conditions (deep snow drifts), and (2) to determine the impact of increased snow and permafrost thawing on surface CO(2) efflux by partitioning respiration into autotrophic and heterotrophic components. Delta(14)C signatures of surface respiration were higher in the deep snow areas, reflecting a decrease in the proportion of autotrophic respiration. The radiocarbon age of soil pore CO(2) sampled near the maximum mid-July thaw depth was approximately 1,000 years in deep snow treatment plots (45-55 cm thaw depth), while CO(2) from the ambient snow areas was approximately 100 years old (30-cm thaw depth). Heterotrophic respiration Delta(14)C signatures from incubations were similar between the two snow depths for the organic horizon and were extremely variable in the mineral horizon, resulting in no significant differences between treatments in either month. Radiocarbon ages of heterotrophically respired C ranged from <50 to 235 years BP in July mineral soil samples and from 1,525 to 8,300 years BP in August samples, suggesting that old soil C in permafrost soils may be metabolized upon thawing. In the surface fluxes, this old C signal is obscured by the organic horizon fluxes, which are significantly higher. Our results indicate that, as permafrost in tussock tundra ecosystems of arctic Alaska thaws, carbon buried up to several thousands of years ago will become an active component of the carbon cycle, potentially accelerating the rise of CO(2) in the atmosphere. |
format |
Article in Journal/Newspaper |
author |
Nowinski, NS Taneva, L Trumbore, SE Welker, JM |
author_facet |
Nowinski, NS Taneva, L Trumbore, SE Welker, JM |
author_sort |
Nowinski, NS |
title |
Decomposition of old organic matter as a result of deeper active layers in a snow depth manipulation experiment. |
title_short |
Decomposition of old organic matter as a result of deeper active layers in a snow depth manipulation experiment. |
title_full |
Decomposition of old organic matter as a result of deeper active layers in a snow depth manipulation experiment. |
title_fullStr |
Decomposition of old organic matter as a result of deeper active layers in a snow depth manipulation experiment. |
title_full_unstemmed |
Decomposition of old organic matter as a result of deeper active layers in a snow depth manipulation experiment. |
title_sort |
decomposition of old organic matter as a result of deeper active layers in a snow depth manipulation experiment. |
publisher |
eScholarship, University of California |
publishDate |
2010 |
url |
http://www.escholarship.org/uc/item/7mh9w489 |
op_coverage |
785 - 792 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic permafrost Tundra Alaska |
genre_facet |
Arctic permafrost Tundra Alaska |
op_source |
Nowinski, NS; Taneva, L; Trumbore, SE; & Welker, JM. (2010). Decomposition of old organic matter as a result of deeper active layers in a snow depth manipulation experiment. Oecologia, 163(3), 785 - 792. doi:10.1007/s00442-009-1556-x. UC Irvine: Retrieved from: http://www.escholarship.org/uc/item/7mh9w489 |
op_relation |
qt7mh9w489 http://www.escholarship.org/uc/item/7mh9w489 |
op_rights |
public |
op_doi |
https://doi.org/10.1007/s00442-009-1556-x |
container_title |
Oecologia |
container_volume |
163 |
container_issue |
3 |
container_start_page |
785 |
op_container_end_page |
792 |
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1766333961483583488 |