The Role of Methane Transport From the Active Layer in Sustaining Methane Emissions and Food Chains in Subarctic Ponds

Olid, Carolina; Zannella, Alberto; Lau, Danny C. P.

doi:10.1029/2020jg005810

Cited by 5 publications

(3 citation statements)

References 94 publications

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“…External delivery of CH 4 may be more likely to cause the differences in observed CH 4 concentrations. Dissolved CH 4 might enter the lake from the adjacent permafrost plateau active layer (Pacheco et al 2014; Olid et al 2021) or may be produced at and transported from the permafrost interface (Walter et al 2006) to the lake sediments. In either case, CH 4 produced and emitted from the thaw edge would be sourced from older, more recently thawed permafrost carbon.…”

Section: Discussionmentioning

confidence: 99%

High ebullitive, millennial‐aged greenhouse gas emissions from thermokarst expansion of peatland lakes in boreal western Canada

Kuhn

Schmidt

Heffernan

et al. 2022

Limnology & Oceanography

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Methane (CH4) and carbon dioxide (CO2) emissions from small peatland lakes may be highly sensitive to climate warming and thermokarst expansion caused by permafrost thaw. We studied effects of thermokarst expansion on ebullitive CH4 and CO2 fluxes and diffusive CH4 fluxes from a peatland thaw lake in boreal western Canada. Ebullitive CH4 fluxes from the thaw edge (236 ± 61 mg CH4 m−2 d−1) were double and quadruple that of the stable lake edge and center, respectively. Modeled diffusive CH4 fluxes did not differ between the thawing and stable edges (~ 50 mg CH4 m−2 d−1) but were double that of the center. Radiocarbon (14C) analysis of CH4 and CO2 bubbles from the thaw edge was older (~ 1211 and 1420 14C yr BP) than from the stable edge and the center (modern to ~ 102 and 50 14C yr BP, respectively). Incubations indicated that deep, old peat sediment was more labile along the thaw edge than in the center. While our study suggested increase CH4 emissions partly derived from millennial‐aged carbon along the thaw edge, accounting for these emissions only increased the estimated total lake CH4 emissions by ~ 10%, which is a much smaller contribution than measured from thermokarst lakes in yedoma regions. Our study suggests that it is important to account for landscape history and lake types when studying the processes that govern the sensitivity of lake greenhouse gas emissions to climate change.

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Section: Discussionmentioning

confidence: 99%

High ebullitive, millennial‐aged greenhouse gas emissions from thermokarst expansion of peatland lakes in boreal western Canada

Kuhn

Schmidt

Heffernan

et al. 2022

Limnology & Oceanography

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“…We also refitted this model using solid peat at the bottom of the active layer as a terrestrial DIC source instead of shallow groundwater DOC. Peatland soils can also export large quantities of CH 4 to fluvial networks, especially from anaerobic conditions in the active layer (Campeau et al, 2014;Dinsmore et al, 2010;Olid et al, 2021 but see Street et al, 2016). This CH 4 can then be made available for autotrophic growth by methane-oxidizing bacteria (Grey, 2016;Kohzu et al, 2004;Raghoebarsing et al, 2005).…”

Section: Statistical Analysis Of Resource Use By Aquatic Primary Producersmentioning

confidence: 99%

Aged soils contribute little to contemporary carbon cycling downstream of thawing permafrost peatlands

Tanentzap

Burd

Kuhn

et al. 2021

Global Change Biology

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“…During summer, groundwater discharge is highly relevant at the peak of active layer thaw, when the flow in rivers is at its minima. Therefore, most of the CH 4 found in Arctic rivers and streams during summer may have originated from deeper soil layers, thus, sustaining the summer aquatic CH 4 emissions (Figures 2 and 3) (Connolly et al., 2020; van Grinsven et al., 2021; Harms et al., 2020; Olid et al., 2021). Because we did not measure the concentration of CH 4 just above the river bed, we could not account for the potential CH 4 efflux from anoxic hyporheic sediments into the water column.…”

Section: Discussionmentioning

confidence: 99%

Effects of Reversal of Water Flow in an Arctic Floodplain River on Fluvial Emissions of CO₂ and CH₄

et al. 2022

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When organic matter from thawed permafrost is released, the sources and sinks of greenhouse gases (GHGs), like carbon dioxide (CO2) and methane (CH4) in Arctic rivers will be influenced in the future. However, the temporal variation, environmental controls, and magnitude of the Arctic riverine GHGs are largely unknown. We measured in situ high temporal resolution concentrations of CO2, CH4, and oxygen (O2) in the Ambolikha River in northeast Siberia between late June and early August 2019. During this period, the largely supersaturated riverine CO2 and CH4 concentrations decreased steadily by 90% and 78%, respectively, while the O2 concentrations increased by 22% and were driven by the decreasing water temperature. Estimated gas fluxes indicate that during late June 2019, significant emissions of CO2 and CH4 were sustained, possibly by external terrestrial sources during flooding, or due to lateral exchange with gas‐rich downstream‐flowing water. In July and early August, the river reversed its flow constantly and limited the water exchange at the site. The composition of dissolved organic matter and microbial communities analyzed in discrete samples also revealed a temporal shift. Furthermore, the cumulative total riverine CO2 emissions (36.8 gC‐CO2 m−2) were nearly five times lower than the CO2 uptake at the adjacent floodplain. Emissions of riverine CH4 (0.21 gC‐CH4 m−2) were 16 times lower than the floodplain CH4 emissions. Our study revealed that the hydraulic connectivity with the land in the late freshet, and reversing flow directions in Arctic streams in summer, regulate riverine carbon replenishment and emissions.

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The Role of Methane Transport From the Active Layer in Sustaining Methane Emissions and Food Chains in Subarctic Ponds

Cited by 5 publications

References 94 publications

High ebullitive, millennial‐aged greenhouse gas emissions from thermokarst expansion of peatland lakes in boreal western Canada

High ebullitive, millennial‐aged greenhouse gas emissions from thermokarst expansion of peatland lakes in boreal western Canada

Aged soils contribute little to contemporary carbon cycling downstream of thawing permafrost peatlands

Effects of Reversal of Water Flow in an Arctic Floodplain River on Fluvial Emissions of CO₂ and CH₄

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The Role of Methane Transport From the Active Layer in Sustaining Methane Emissions and Food Chains in Subarctic Ponds

Cited by 5 publications

References 94 publications

High ebullitive, millennial‐aged greenhouse gas emissions from thermokarst expansion of peatland lakes in boreal western Canada

High ebullitive, millennial‐aged greenhouse gas emissions from thermokarst expansion of peatland lakes in boreal western Canada

Aged soils contribute little to contemporary carbon cycling downstream of thawing permafrost peatlands

Effects of Reversal of Water Flow in an Arctic Floodplain River on Fluvial Emissions of CO2 and CH4

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Effects of Reversal of Water Flow in an Arctic Floodplain River on Fluvial Emissions of CO₂ and CH₄