Influences of Hillslope Biogeochemistry on Anaerobic Soil Organic Matter Decomposition in a Tundra Watershed
We investigated rates and controls on greenhouse gas (CO2 and CH4) production in two contrasting water-saturated tundra soils within a permafrost-affected watershed near Nome, Alaska, United States. Three years of field sample analysis have shown that soil from a fen-like area in the toeslope of the...
Published in: | Journal of Geophysical Research: Biogeosciences |
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Online Access: | https://escholarship.org/uc/item/5gg1k6zm https://escholarship.org/content/qt5gg1k6zm/qt5gg1k6zm.pdf https://doi.org/10.1029/2019jg005512 |
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ftcdlib:oai:escholarship.org:ark:/13030/qt5gg1k6zm 2024-09-15T18:20:26+00:00 Influences of Hillslope Biogeochemistry on Anaerobic Soil Organic Matter Decomposition in a Tundra Watershed Philben, Michael Taş, Neslihan Chen, Hongmei Wullschleger, Stan D Kholodov, Alexander Graham, David E Gu, Baohua 2020-07-01 application/pdf https://escholarship.org/uc/item/5gg1k6zm https://escholarship.org/content/qt5gg1k6zm/qt5gg1k6zm.pdf https://doi.org/10.1029/2019jg005512 unknown eScholarship, University of California qt5gg1k6zm https://escholarship.org/uc/item/5gg1k6zm https://escholarship.org/content/qt5gg1k6zm/qt5gg1k6zm.pdf doi:10.1029/2019jg005512 public Journal of Geophysical Research Biogeosciences, vol 125, iss 7 Climate Action methane Arctic permafrost hillslope biogeochemistry microbial nitrogen limitation Geophysics article 2020 ftcdlib https://doi.org/10.1029/2019jg005512 2024-06-28T06:28:19Z We investigated rates and controls on greenhouse gas (CO2 and CH4) production in two contrasting water-saturated tundra soils within a permafrost-affected watershed near Nome, Alaska, United States. Three years of field sample analysis have shown that soil from a fen-like area in the toeslope of the watershed had higher pH and higher porewater ion concentrations than soil collected from a bog-like peat plateau at the top of the hillslope. The influence of these contrasting geochemical and topographic environments on CO2 and CH4 production was tested in soil microcosms by incubating both the organic- and mineral-layer soils anaerobically for 55days. Nitrogen (as NH4Cl) was added to half of the microcosms to test potential effects of N limitation on microbial greenhouse gas production. We found that the organic toeslope soils produced more CO2 and CH4, fueled by higher pH and higher concentrations of water-extractable organic C (WEOC). Our results also indicate N limitation on CO2 production in the peat plateau soils but not the toeslope soils. Together these results suggest that the weathering and leaching of ions and nutrients from tundra hillslopes can increase the rate of anaerobic soil organic matter decomposition in downslope soils by (1) increasing the pH of soil porewater; (2) providing bioavailable WEOC and fermentation products such as acetate; and (3) relieving microbial N limitation through nutrient runoff. We conclude that the soil geochemistry as mediated by landscape position is an important factor influencing the rate and magnitude of greenhouse gas production in tundra soils. Article in Journal/Newspaper Nome Peat Peat plateau permafrost Tundra Alaska University of California: eScholarship Journal of Geophysical Research: Biogeosciences 125 7 |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
unknown |
topic |
Climate Action methane Arctic permafrost hillslope biogeochemistry microbial nitrogen limitation Geophysics |
spellingShingle |
Climate Action methane Arctic permafrost hillslope biogeochemistry microbial nitrogen limitation Geophysics Philben, Michael Taş, Neslihan Chen, Hongmei Wullschleger, Stan D Kholodov, Alexander Graham, David E Gu, Baohua Influences of Hillslope Biogeochemistry on Anaerobic Soil Organic Matter Decomposition in a Tundra Watershed |
topic_facet |
Climate Action methane Arctic permafrost hillslope biogeochemistry microbial nitrogen limitation Geophysics |
description |
We investigated rates and controls on greenhouse gas (CO2 and CH4) production in two contrasting water-saturated tundra soils within a permafrost-affected watershed near Nome, Alaska, United States. Three years of field sample analysis have shown that soil from a fen-like area in the toeslope of the watershed had higher pH and higher porewater ion concentrations than soil collected from a bog-like peat plateau at the top of the hillslope. The influence of these contrasting geochemical and topographic environments on CO2 and CH4 production was tested in soil microcosms by incubating both the organic- and mineral-layer soils anaerobically for 55days. Nitrogen (as NH4Cl) was added to half of the microcosms to test potential effects of N limitation on microbial greenhouse gas production. We found that the organic toeslope soils produced more CO2 and CH4, fueled by higher pH and higher concentrations of water-extractable organic C (WEOC). Our results also indicate N limitation on CO2 production in the peat plateau soils but not the toeslope soils. Together these results suggest that the weathering and leaching of ions and nutrients from tundra hillslopes can increase the rate of anaerobic soil organic matter decomposition in downslope soils by (1) increasing the pH of soil porewater; (2) providing bioavailable WEOC and fermentation products such as acetate; and (3) relieving microbial N limitation through nutrient runoff. We conclude that the soil geochemistry as mediated by landscape position is an important factor influencing the rate and magnitude of greenhouse gas production in tundra soils. |
format |
Article in Journal/Newspaper |
author |
Philben, Michael Taş, Neslihan Chen, Hongmei Wullschleger, Stan D Kholodov, Alexander Graham, David E Gu, Baohua |
author_facet |
Philben, Michael Taş, Neslihan Chen, Hongmei Wullschleger, Stan D Kholodov, Alexander Graham, David E Gu, Baohua |
author_sort |
Philben, Michael |
title |
Influences of Hillslope Biogeochemistry on Anaerobic Soil Organic Matter Decomposition in a Tundra Watershed |
title_short |
Influences of Hillslope Biogeochemistry on Anaerobic Soil Organic Matter Decomposition in a Tundra Watershed |
title_full |
Influences of Hillslope Biogeochemistry on Anaerobic Soil Organic Matter Decomposition in a Tundra Watershed |
title_fullStr |
Influences of Hillslope Biogeochemistry on Anaerobic Soil Organic Matter Decomposition in a Tundra Watershed |
title_full_unstemmed |
Influences of Hillslope Biogeochemistry on Anaerobic Soil Organic Matter Decomposition in a Tundra Watershed |
title_sort |
influences of hillslope biogeochemistry on anaerobic soil organic matter decomposition in a tundra watershed |
publisher |
eScholarship, University of California |
publishDate |
2020 |
url |
https://escholarship.org/uc/item/5gg1k6zm https://escholarship.org/content/qt5gg1k6zm/qt5gg1k6zm.pdf https://doi.org/10.1029/2019jg005512 |
genre |
Nome Peat Peat plateau permafrost Tundra Alaska |
genre_facet |
Nome Peat Peat plateau permafrost Tundra Alaska |
op_source |
Journal of Geophysical Research Biogeosciences, vol 125, iss 7 |
op_relation |
qt5gg1k6zm https://escholarship.org/uc/item/5gg1k6zm https://escholarship.org/content/qt5gg1k6zm/qt5gg1k6zm.pdf doi:10.1029/2019jg005512 |
op_rights |
public |
op_doi |
https://doi.org/10.1029/2019jg005512 |
container_title |
Journal of Geophysical Research: Biogeosciences |
container_volume |
125 |
container_issue |
7 |
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1810458813430497280 |