Carbon dynamics in highly heterotrophic subarctic thaw ponds
Global warming has accelerated the formation of permafrost thaw ponds in several subarctic and arctic regions. These ponds are net heterotrophic as evidenced by their greenhouse gas (GHG) supersaturation levels (CO 2 and CH 4 ), and generally receive large terrestrial carbon inputs from the thawing...
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ftdoajarticles:oai:doaj.org/article:e577a66e9b6049039506d30c34d3d053 2023-05-15T15:13:35+02:00 Carbon dynamics in highly heterotrophic subarctic thaw ponds T. Roiha I. Laurion M. Rautio 2015-12-01T00:00:00Z https://doi.org/10.5194/bg-12-7223-2015 https://doaj.org/article/e577a66e9b6049039506d30c34d3d053 EN eng Copernicus Publications http://www.biogeosciences.net/12/7223/2015/bg-12-7223-2015.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 1726-4170 1726-4189 doi:10.5194/bg-12-7223-2015 https://doaj.org/article/e577a66e9b6049039506d30c34d3d053 Biogeosciences, Vol 12, Iss 23, Pp 7223-7237 (2015) Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 article 2015 ftdoajarticles https://doi.org/10.5194/bg-12-7223-2015 2022-12-31T14:06:17Z Global warming has accelerated the formation of permafrost thaw ponds in several subarctic and arctic regions. These ponds are net heterotrophic as evidenced by their greenhouse gas (GHG) supersaturation levels (CO 2 and CH 4 ), and generally receive large terrestrial carbon inputs from the thawing and eroding permafrost. We measured seasonal and vertical variations in the concentration and type of dissolved organic matter (DOM) in five subarctic thaw (thermokarst) ponds in northern Quebec, and explored how environmental gradients influenced heterotrophic and phototrophic biomass and productivity. Late winter DOM had low aromaticity indicating reduced inputs of terrestrial carbon, while the high concentration of dissolved organic carbon (DOC) suggests that some production of non-chromophoric dissolved compounds by the microbial food web took place under the ice cover. Summer DOM had a strong terrestrial signature, but was also characterized with significant inputs of algal-derived carbon, especially at the pond surface. During late winter, bacterial production was low (maximum of 0.8 mg C m −3 d −1 ) and was largely based on free-living bacterioplankton (58 %). Bacterial production in summer was high (up to 58 mg C m −3 d −1 ), dominated by particle-attached bacteria (67 %), and strongly correlated with the amount of terrestrial carbon. Primary production was restricted to summer surface waters due to strong light limitation deeper in the water column or in winter. The phototrophic biomass was equal to the heterotrophic biomass, but as the algae were mostly composed of mixotrophic species, most probably they used bacteria rather than solar energy in such shaded ponds. Our results point to a strong heterotrophic energy pathway in these thaw pond ecosystems, where bacterioplankton dominates the production of new carbon biomass in both summer and winter. Article in Journal/Newspaper Arctic Global warming Ice permafrost Subarctic Thermokarst Directory of Open Access Journals: DOAJ Articles Arctic Biogeosciences 12 23 7223 7237 |
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Directory of Open Access Journals: DOAJ Articles |
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ftdoajarticles |
language |
English |
topic |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
spellingShingle |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 T. Roiha I. Laurion M. Rautio Carbon dynamics in highly heterotrophic subarctic thaw ponds |
topic_facet |
Ecology QH540-549.5 Life QH501-531 Geology QE1-996.5 |
description |
Global warming has accelerated the formation of permafrost thaw ponds in several subarctic and arctic regions. These ponds are net heterotrophic as evidenced by their greenhouse gas (GHG) supersaturation levels (CO 2 and CH 4 ), and generally receive large terrestrial carbon inputs from the thawing and eroding permafrost. We measured seasonal and vertical variations in the concentration and type of dissolved organic matter (DOM) in five subarctic thaw (thermokarst) ponds in northern Quebec, and explored how environmental gradients influenced heterotrophic and phototrophic biomass and productivity. Late winter DOM had low aromaticity indicating reduced inputs of terrestrial carbon, while the high concentration of dissolved organic carbon (DOC) suggests that some production of non-chromophoric dissolved compounds by the microbial food web took place under the ice cover. Summer DOM had a strong terrestrial signature, but was also characterized with significant inputs of algal-derived carbon, especially at the pond surface. During late winter, bacterial production was low (maximum of 0.8 mg C m −3 d −1 ) and was largely based on free-living bacterioplankton (58 %). Bacterial production in summer was high (up to 58 mg C m −3 d −1 ), dominated by particle-attached bacteria (67 %), and strongly correlated with the amount of terrestrial carbon. Primary production was restricted to summer surface waters due to strong light limitation deeper in the water column or in winter. The phototrophic biomass was equal to the heterotrophic biomass, but as the algae were mostly composed of mixotrophic species, most probably they used bacteria rather than solar energy in such shaded ponds. Our results point to a strong heterotrophic energy pathway in these thaw pond ecosystems, where bacterioplankton dominates the production of new carbon biomass in both summer and winter. |
format |
Article in Journal/Newspaper |
author |
T. Roiha I. Laurion M. Rautio |
author_facet |
T. Roiha I. Laurion M. Rautio |
author_sort |
T. Roiha |
title |
Carbon dynamics in highly heterotrophic subarctic thaw ponds |
title_short |
Carbon dynamics in highly heterotrophic subarctic thaw ponds |
title_full |
Carbon dynamics in highly heterotrophic subarctic thaw ponds |
title_fullStr |
Carbon dynamics in highly heterotrophic subarctic thaw ponds |
title_full_unstemmed |
Carbon dynamics in highly heterotrophic subarctic thaw ponds |
title_sort |
carbon dynamics in highly heterotrophic subarctic thaw ponds |
publisher |
Copernicus Publications |
publishDate |
2015 |
url |
https://doi.org/10.5194/bg-12-7223-2015 https://doaj.org/article/e577a66e9b6049039506d30c34d3d053 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic Global warming Ice permafrost Subarctic Thermokarst |
genre_facet |
Arctic Global warming Ice permafrost Subarctic Thermokarst |
op_source |
Biogeosciences, Vol 12, Iss 23, Pp 7223-7237 (2015) |
op_relation |
http://www.biogeosciences.net/12/7223/2015/bg-12-7223-2015.pdf https://doaj.org/toc/1726-4170 https://doaj.org/toc/1726-4189 1726-4170 1726-4189 doi:10.5194/bg-12-7223-2015 https://doaj.org/article/e577a66e9b6049039506d30c34d3d053 |
op_doi |
https://doi.org/10.5194/bg-12-7223-2015 |
container_title |
Biogeosciences |
container_volume |
12 |
container_issue |
23 |
container_start_page |
7223 |
op_container_end_page |
7237 |
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1766344125782687744 |