The role of watershed characteristics, permafrost thaw, and wildfire on dissolved organic carbon biodegradability and water chemistry in Arctic headwater streams
In the Alaskan Arctic, rapid climate change is increasing the frequency of disturbance including wildfire and permafrost collapse. These pulse disturbances may influence the delivery of dissolved organic carbon (DOC) to aquatic ecosystems, however the magnitude of these effects compared to the natur...
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ftcopernicus:oai:publications.copernicus.org:bg28856 2023-05-15T14:54:14+02:00 The role of watershed characteristics, permafrost thaw, and wildfire on dissolved organic carbon biodegradability and water chemistry in Arctic headwater streams Larouche, J. R. Abbott, B. W. Bowden, W. B. Jones, J. B. 2018-09-27 application/pdf https://doi.org/10.5194/bg-12-4221-2015 https://www.biogeosciences.net/12/4221/2015/ eng eng doi:10.5194/bg-12-4221-2015 https://www.biogeosciences.net/12/4221/2015/ eISSN: 1726-4189 Text 2018 ftcopernicus https://doi.org/10.5194/bg-12-4221-2015 2019-12-24T09:53:18Z In the Alaskan Arctic, rapid climate change is increasing the frequency of disturbance including wildfire and permafrost collapse. These pulse disturbances may influence the delivery of dissolved organic carbon (DOC) to aquatic ecosystems, however the magnitude of these effects compared to the natural background variability of DOC at the watershed scale is not well known. We measured DOC quantity, composition, and biodegradability from 14 river and stream reaches (watershed sizes ranging from 1.5–167 km 2 ) some of which were impacted by permafrost collapse (thermokarst) and fire. We found that region had a significant impact on quantity and biodegradability of DOC, likely driven by landscape and watershed characteristics such as lithology, soil and vegetation type, elevation, and glacial age. However, contrary to our hypothesis, we found that streams disturbed by thermokarst and fire did not contain significantly altered labile DOC fractions compared to adjacent reference waters, potentially due to rapid ecosystem recovery after fire and thermokarst as well as the limited spatial extent of thermokarst. Overall, biodegradable DOC ranged from 4 to 46 % and contrary to patterns of DOC biodegradability in large Arctic rivers, seasonal variation in DOC biodegradability showed no clear pattern between sites, potentially related to stream geomorphology and position along the river network. While thermokarst and fire can alter DOC quantity and biodegradability at the scale of the feature, we conclude that tundra ecosystems are resilient to these types of disturbance. Text Arctic Climate change permafrost Thermokarst Tundra Copernicus Publications: E-Journals Arctic Biogeosciences 12 14 4221 4233 |
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Copernicus Publications: E-Journals |
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English |
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In the Alaskan Arctic, rapid climate change is increasing the frequency of disturbance including wildfire and permafrost collapse. These pulse disturbances may influence the delivery of dissolved organic carbon (DOC) to aquatic ecosystems, however the magnitude of these effects compared to the natural background variability of DOC at the watershed scale is not well known. We measured DOC quantity, composition, and biodegradability from 14 river and stream reaches (watershed sizes ranging from 1.5–167 km 2 ) some of which were impacted by permafrost collapse (thermokarst) and fire. We found that region had a significant impact on quantity and biodegradability of DOC, likely driven by landscape and watershed characteristics such as lithology, soil and vegetation type, elevation, and glacial age. However, contrary to our hypothesis, we found that streams disturbed by thermokarst and fire did not contain significantly altered labile DOC fractions compared to adjacent reference waters, potentially due to rapid ecosystem recovery after fire and thermokarst as well as the limited spatial extent of thermokarst. Overall, biodegradable DOC ranged from 4 to 46 % and contrary to patterns of DOC biodegradability in large Arctic rivers, seasonal variation in DOC biodegradability showed no clear pattern between sites, potentially related to stream geomorphology and position along the river network. While thermokarst and fire can alter DOC quantity and biodegradability at the scale of the feature, we conclude that tundra ecosystems are resilient to these types of disturbance. |
format |
Text |
author |
Larouche, J. R. Abbott, B. W. Bowden, W. B. Jones, J. B. |
spellingShingle |
Larouche, J. R. Abbott, B. W. Bowden, W. B. Jones, J. B. The role of watershed characteristics, permafrost thaw, and wildfire on dissolved organic carbon biodegradability and water chemistry in Arctic headwater streams |
author_facet |
Larouche, J. R. Abbott, B. W. Bowden, W. B. Jones, J. B. |
author_sort |
Larouche, J. R. |
title |
The role of watershed characteristics, permafrost thaw, and wildfire on dissolved organic carbon biodegradability and water chemistry in Arctic headwater streams |
title_short |
The role of watershed characteristics, permafrost thaw, and wildfire on dissolved organic carbon biodegradability and water chemistry in Arctic headwater streams |
title_full |
The role of watershed characteristics, permafrost thaw, and wildfire on dissolved organic carbon biodegradability and water chemistry in Arctic headwater streams |
title_fullStr |
The role of watershed characteristics, permafrost thaw, and wildfire on dissolved organic carbon biodegradability and water chemistry in Arctic headwater streams |
title_full_unstemmed |
The role of watershed characteristics, permafrost thaw, and wildfire on dissolved organic carbon biodegradability and water chemistry in Arctic headwater streams |
title_sort |
role of watershed characteristics, permafrost thaw, and wildfire on dissolved organic carbon biodegradability and water chemistry in arctic headwater streams |
publishDate |
2018 |
url |
https://doi.org/10.5194/bg-12-4221-2015 https://www.biogeosciences.net/12/4221/2015/ |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic Climate change permafrost Thermokarst Tundra |
genre_facet |
Arctic Climate change permafrost Thermokarst Tundra |
op_source |
eISSN: 1726-4189 |
op_relation |
doi:10.5194/bg-12-4221-2015 https://www.biogeosciences.net/12/4221/2015/ |
op_doi |
https://doi.org/10.5194/bg-12-4221-2015 |
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Biogeosciences |
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12 |
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14 |
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4221 |
op_container_end_page |
4233 |
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1766325952572293120 |