Seasonal Sources of Whole‐Lake CH4 and CO2 Emissions From Interior Alaskan Thermokarst Lakes
The lakes that form via ice-rich permafrost thaw emit CH4 and CO2 to the atmosphere from previously frozen ancient permafrost sources. Despite this potential to positively feedback to climate change, lake carbon emission sources are not well understood on whole-lake scales, complicating upscaling. I...
Published in: | Journal of Geophysical Research: Biogeosciences |
---|---|
Main Authors: | , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | unknown |
Published: |
eScholarship, University of California
2019
|
Subjects: | |
Online Access: | https://escholarship.org/uc/item/8qz3j1b6 https://escholarship.org/content/qt8qz3j1b6/qt8qz3j1b6.pdf https://doi.org/10.1029/2018jg004735 |
id |
ftcdlib:oai:escholarship.org:ark:/13030/qt8qz3j1b6 |
---|---|
record_format |
openpolar |
spelling |
ftcdlib:oai:escholarship.org:ark:/13030/qt8qz3j1b6 2024-09-15T18:11:33+00:00 Seasonal Sources of Whole‐Lake CH4 and CO2 Emissions From Interior Alaskan Thermokarst Lakes Elder, CD Schweiger, M Lam, B Crook, ED Xu, X Walker, J Anthony, KM Walter Czimczik, CI 1209 - 1229 2019-05-01 application/pdf https://escholarship.org/uc/item/8qz3j1b6 https://escholarship.org/content/qt8qz3j1b6/qt8qz3j1b6.pdf https://doi.org/10.1029/2018jg004735 unknown eScholarship, University of California qt8qz3j1b6 https://escholarship.org/uc/item/8qz3j1b6 https://escholarship.org/content/qt8qz3j1b6/qt8qz3j1b6.pdf doi:10.1029/2018jg004735 public Journal of Geophysical Research Biogeosciences, vol 124, iss 5 Climate Action thermokarst methane lakes radiocarbon carbon dioxide climate change Geophysics article 2019 ftcdlib https://doi.org/10.1029/2018jg004735 2024-06-28T06:28:19Z The lakes that form via ice-rich permafrost thaw emit CH4 and CO2 to the atmosphere from previously frozen ancient permafrost sources. Despite this potential to positively feedback to climate change, lake carbon emission sources are not well understood on whole-lake scales, complicating upscaling. In this study, we used observations of radiocarbon (14C) and stable carbon (13C) isotopes in the summer and winter dissolved CH4 and CO2 pools, ebullition-CH4, and multiple independent mass balance approaches to characterize whole-lake emission sources and apportion annual emission pathways. Observations focused on five lakes with variable thermokarst in interior Alaska. The 14C age of discrete ebullition-CH4 seeps ranged from 395±15 to 28,240±150 YBP across all study lakes; however, dissolved 14CH4 was younger than 4,730 YBP. In the primary study lake, Goldstream L., the integrated whole-lake 14C age of ebullition-CH4, as determined by three different approaches, ranged from 3,290 to 6,740 YBP. A new dissolved-14C-CH4-based approach to estimating ebullition 14C age and flux showed close agreement to previous ice-bubble surveys and bubble-trap flux estimates. Differences in open water versus ice-covered dissolved gas concentrations and their 14C and 13C isotopes revealed the influence of winter ice trapping and forcing ebullition-CH4 into the underlying water column, where it comprised 50% of the total dissolved CH4 pool by the end of winter. Across the study lakes, we found a relationship between the whole-lake 14C age of dissolved CH4 and CO2 and the extent of active thermokarst, representing a positive feedback system that is sensitive to climate warming. Article in Journal/Newspaper Ice permafrost Thermokarst Alaska University of California: eScholarship Journal of Geophysical Research: Biogeosciences 124 5 1209 1229 |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
unknown |
topic |
Climate Action thermokarst methane lakes radiocarbon carbon dioxide climate change Geophysics |
spellingShingle |
Climate Action thermokarst methane lakes radiocarbon carbon dioxide climate change Geophysics Elder, CD Schweiger, M Lam, B Crook, ED Xu, X Walker, J Anthony, KM Walter Czimczik, CI Seasonal Sources of Whole‐Lake CH4 and CO2 Emissions From Interior Alaskan Thermokarst Lakes |
topic_facet |
Climate Action thermokarst methane lakes radiocarbon carbon dioxide climate change Geophysics |
description |
The lakes that form via ice-rich permafrost thaw emit CH4 and CO2 to the atmosphere from previously frozen ancient permafrost sources. Despite this potential to positively feedback to climate change, lake carbon emission sources are not well understood on whole-lake scales, complicating upscaling. In this study, we used observations of radiocarbon (14C) and stable carbon (13C) isotopes in the summer and winter dissolved CH4 and CO2 pools, ebullition-CH4, and multiple independent mass balance approaches to characterize whole-lake emission sources and apportion annual emission pathways. Observations focused on five lakes with variable thermokarst in interior Alaska. The 14C age of discrete ebullition-CH4 seeps ranged from 395±15 to 28,240±150 YBP across all study lakes; however, dissolved 14CH4 was younger than 4,730 YBP. In the primary study lake, Goldstream L., the integrated whole-lake 14C age of ebullition-CH4, as determined by three different approaches, ranged from 3,290 to 6,740 YBP. A new dissolved-14C-CH4-based approach to estimating ebullition 14C age and flux showed close agreement to previous ice-bubble surveys and bubble-trap flux estimates. Differences in open water versus ice-covered dissolved gas concentrations and their 14C and 13C isotopes revealed the influence of winter ice trapping and forcing ebullition-CH4 into the underlying water column, where it comprised 50% of the total dissolved CH4 pool by the end of winter. Across the study lakes, we found a relationship between the whole-lake 14C age of dissolved CH4 and CO2 and the extent of active thermokarst, representing a positive feedback system that is sensitive to climate warming. |
format |
Article in Journal/Newspaper |
author |
Elder, CD Schweiger, M Lam, B Crook, ED Xu, X Walker, J Anthony, KM Walter Czimczik, CI |
author_facet |
Elder, CD Schweiger, M Lam, B Crook, ED Xu, X Walker, J Anthony, KM Walter Czimczik, CI |
author_sort |
Elder, CD |
title |
Seasonal Sources of Whole‐Lake CH4 and CO2 Emissions From Interior Alaskan Thermokarst Lakes |
title_short |
Seasonal Sources of Whole‐Lake CH4 and CO2 Emissions From Interior Alaskan Thermokarst Lakes |
title_full |
Seasonal Sources of Whole‐Lake CH4 and CO2 Emissions From Interior Alaskan Thermokarst Lakes |
title_fullStr |
Seasonal Sources of Whole‐Lake CH4 and CO2 Emissions From Interior Alaskan Thermokarst Lakes |
title_full_unstemmed |
Seasonal Sources of Whole‐Lake CH4 and CO2 Emissions From Interior Alaskan Thermokarst Lakes |
title_sort |
seasonal sources of whole‐lake ch4 and co2 emissions from interior alaskan thermokarst lakes |
publisher |
eScholarship, University of California |
publishDate |
2019 |
url |
https://escholarship.org/uc/item/8qz3j1b6 https://escholarship.org/content/qt8qz3j1b6/qt8qz3j1b6.pdf https://doi.org/10.1029/2018jg004735 |
op_coverage |
1209 - 1229 |
genre |
Ice permafrost Thermokarst Alaska |
genre_facet |
Ice permafrost Thermokarst Alaska |
op_source |
Journal of Geophysical Research Biogeosciences, vol 124, iss 5 |
op_relation |
qt8qz3j1b6 https://escholarship.org/uc/item/8qz3j1b6 https://escholarship.org/content/qt8qz3j1b6/qt8qz3j1b6.pdf doi:10.1029/2018jg004735 |
op_rights |
public |
op_doi |
https://doi.org/10.1029/2018jg004735 |
container_title |
Journal of Geophysical Research: Biogeosciences |
container_volume |
124 |
container_issue |
5 |
container_start_page |
1209 |
op_container_end_page |
1229 |
_version_ |
1810449145443385344 |