Dissolved organic matter photolysis in Canadian arctic thaw ponds
The abundant thaw lakes and ponds in the circumarctic receive a new pool of organic carbon as permafrost peat soils degrade, which can be exposed to significant irradiance that potentially increases as climate warms and ice cover shortens. Exposure to sunlight is known to accelerate the transformati...
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ftdoajarticles:oai:doaj.org/article:b9654258e12a4c389958341936bc9d34 2023-09-05T13:17:16+02:00 Dissolved organic matter photolysis in Canadian arctic thaw ponds Isabelle Laurion Natalie Mladenov 2013-01-01T00:00:00Z https://doi.org/10.1088/1748-9326/8/3/035026 https://doaj.org/article/b9654258e12a4c389958341936bc9d34 EN eng IOP Publishing https://doi.org/10.1088/1748-9326/8/3/035026 https://doaj.org/toc/1748-9326 doi:10.1088/1748-9326/8/3/035026 1748-9326 https://doaj.org/article/b9654258e12a4c389958341936bc9d34 Environmental Research Letters, Vol 8, Iss 3, p 035026 (2013) DOM photobleaching thermokarst lakes permafrost Environmental technology. Sanitary engineering TD1-1066 Environmental sciences GE1-350 Science Q Physics QC1-999 article 2013 ftdoajarticles https://doi.org/10.1088/1748-9326/8/3/035026 2023-08-13T00:37:34Z The abundant thaw lakes and ponds in the circumarctic receive a new pool of organic carbon as permafrost peat soils degrade, which can be exposed to significant irradiance that potentially increases as climate warms and ice cover shortens. Exposure to sunlight is known to accelerate the transformation of dissolved organic matter (DOM) into molecules that can be more readily used by microbes. We sampled the water from two common classes of ponds found in the ice-wedge system of continuous permafrost regions of Canada, polygonal and runnel ponds, and followed the transformation of DOM over 12 days by looking at dissolved organic carbon (DOC) concentration and DOM absorption and fluorescence properties. The results indicate a relatively fast decay of color (3.4 and 1.6% loss d ^−1 of absorption at 320 nm for the polygonal and runnel pond, respectively) and fluorescence (6.1 and 8.3% loss d ^−1 of total fluorescent components, respectively) at the pond surface, faster in the case of humic-like components, but insignificant losses of DOC over the observed period. This result indicates that direct DOM mineralization (photochemical production of CO _2 ) is apparently minor in thaw ponds compared to the photochemical transformation of DOM into less chromophoric and likely more labile molecules with a greater potential for microbial mineralization. Therefore, DOM photolysis in arctic thaw ponds can be considered as a catalytic mechanism, accelerating the microbial turnover of mobilized organic matter from thawing permafrost and the production of greenhouse gases, especially in the most shallow ponds. Under a warming climate, this mechanism will intensify as summers lengthen. Article in Journal/Newspaper Arctic Ice permafrost Thermokarst wedge* Directory of Open Access Journals: DOAJ Articles Arctic Canada Environmental Research Letters 8 3 035026 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
DOM photobleaching thermokarst lakes permafrost Environmental technology. Sanitary engineering TD1-1066 Environmental sciences GE1-350 Science Q Physics QC1-999 |
spellingShingle |
DOM photobleaching thermokarst lakes permafrost Environmental technology. Sanitary engineering TD1-1066 Environmental sciences GE1-350 Science Q Physics QC1-999 Isabelle Laurion Natalie Mladenov Dissolved organic matter photolysis in Canadian arctic thaw ponds |
topic_facet |
DOM photobleaching thermokarst lakes permafrost Environmental technology. Sanitary engineering TD1-1066 Environmental sciences GE1-350 Science Q Physics QC1-999 |
description |
The abundant thaw lakes and ponds in the circumarctic receive a new pool of organic carbon as permafrost peat soils degrade, which can be exposed to significant irradiance that potentially increases as climate warms and ice cover shortens. Exposure to sunlight is known to accelerate the transformation of dissolved organic matter (DOM) into molecules that can be more readily used by microbes. We sampled the water from two common classes of ponds found in the ice-wedge system of continuous permafrost regions of Canada, polygonal and runnel ponds, and followed the transformation of DOM over 12 days by looking at dissolved organic carbon (DOC) concentration and DOM absorption and fluorescence properties. The results indicate a relatively fast decay of color (3.4 and 1.6% loss d ^−1 of absorption at 320 nm for the polygonal and runnel pond, respectively) and fluorescence (6.1 and 8.3% loss d ^−1 of total fluorescent components, respectively) at the pond surface, faster in the case of humic-like components, but insignificant losses of DOC over the observed period. This result indicates that direct DOM mineralization (photochemical production of CO _2 ) is apparently minor in thaw ponds compared to the photochemical transformation of DOM into less chromophoric and likely more labile molecules with a greater potential for microbial mineralization. Therefore, DOM photolysis in arctic thaw ponds can be considered as a catalytic mechanism, accelerating the microbial turnover of mobilized organic matter from thawing permafrost and the production of greenhouse gases, especially in the most shallow ponds. Under a warming climate, this mechanism will intensify as summers lengthen. |
format |
Article in Journal/Newspaper |
author |
Isabelle Laurion Natalie Mladenov |
author_facet |
Isabelle Laurion Natalie Mladenov |
author_sort |
Isabelle Laurion |
title |
Dissolved organic matter photolysis in Canadian arctic thaw ponds |
title_short |
Dissolved organic matter photolysis in Canadian arctic thaw ponds |
title_full |
Dissolved organic matter photolysis in Canadian arctic thaw ponds |
title_fullStr |
Dissolved organic matter photolysis in Canadian arctic thaw ponds |
title_full_unstemmed |
Dissolved organic matter photolysis in Canadian arctic thaw ponds |
title_sort |
dissolved organic matter photolysis in canadian arctic thaw ponds |
publisher |
IOP Publishing |
publishDate |
2013 |
url |
https://doi.org/10.1088/1748-9326/8/3/035026 https://doaj.org/article/b9654258e12a4c389958341936bc9d34 |
geographic |
Arctic Canada |
geographic_facet |
Arctic Canada |
genre |
Arctic Ice permafrost Thermokarst wedge* |
genre_facet |
Arctic Ice permafrost Thermokarst wedge* |
op_source |
Environmental Research Letters, Vol 8, Iss 3, p 035026 (2013) |
op_relation |
https://doi.org/10.1088/1748-9326/8/3/035026 https://doaj.org/toc/1748-9326 doi:10.1088/1748-9326/8/3/035026 1748-9326 https://doaj.org/article/b9654258e12a4c389958341936bc9d34 |
op_doi |
https://doi.org/10.1088/1748-9326/8/3/035026 |
container_title |
Environmental Research Letters |
container_volume |
8 |
container_issue |
3 |
container_start_page |
035026 |
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1776198509627703296 |