Effects of long-term climate trends on the methane and CO2 exchange processes of Toolik Lake, Alaska

dc.contributor.author Eugster, Werner
dc.contributor.author DelSontro, Tonya
dc.contributor.author Laundre, James A.
dc.contributor.author Dobkowski, Jason
dc.contributor.author Shaver, Gaius R.
dc.contributor.author Kling, George W.
dc.date.accessioned 2023-04-04T17:34:02Z
dc.date.available 2023-04-04T17:34:02Z
dc.date.issued 2022-09-13
dc.description © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Eugster, W., DelSontro, T., Laundre, J., Dobkowski, J., Shaver, G., & Kling, G. Effects of long-term climate trends on the methane and CO2 exchange processes of Toolik Lake, Alaska. Frontiers in Environmental Science, 10, (2022): 948529, https://doi.org/10.3389/fenvs.2022.948529.
dc.description.abstract Methane and carbon dioxide effluxes from aquatic systems in the Arctic will affect and likely amplify global change. As permafrost thaws in a warming world, more dissolved organic carbon (DOC) and greenhouse gases are produced and move from soils to surface waters where the DOC can be oxidized to CO2 and also released to the atmosphere. Our main study objective is to measure the release of carbon to the atmosphere via effluxes of methane (CH 4) and carbon dioxide (CO2) from Toolik Lake, a deep, dimictic, low-arctic lake in northern Alaska. By combining direct eddy covariance flux measurements with continuous gas pressure measurements in the lake surface waters, we quantified the k600 piston velocity that controls gas flux across the air–water interface. Our measured k values for CH4 and CO2 were substantially above predictions from several models at low to moderate wind speeds, and only converged on model predictions at the highest wind speeds. We attribute this higher flux at low wind speeds to effects on water-side turbulence resulting from how the surrounding tundra vegetation and topography increase atmospheric turbulence considerably in this lake, above the level observed over large ocean surfaces. We combine this process-level understanding of gas exchange with the trends of a climate-relevant long-term (30 + years) meteorological data set at Toolik Lake to examine short-term variations (2015 ice-free season) and interannual variability (2010–2015 ice-free seasons) of CH4 and CO2 fluxes. We argue that the biological processing of DOC substrate that becomes available for decomposition as the tundra soil warms is important for understanding future trends in aquatic gas fluxes, whereas the variability and long-term trends of the physical and meteorological variables primarily affect the timing of when higher or lower than average fluxes are observed. We see no evidence suggesting that a tipping point will be reached soon to change the status of the aquatic system from gas source to sink. We estimate that changes in CH4 and CO2 fluxes will be constrained with a range of +30% and −10% of their current values over the next 30 years.
dc.description.sponsorship We acknowledge support from the Arctic LTER grants NSF-DEB-1637459, 1026843, 1754835, NSF-PLR 1504006, and supplemental funding from the NSF-NEON and OPP-AON programs. WE acknowledges additional funding received from ETH Zurich scientific equipment grants 0-43350-07 and 0–43683–11.
dc.identifier.citation Eugster, W., DelSontro, T., Laundre, J., Dobkowski, J., Shaver, G., & Kling, G. (2022). Effects of long-term climate trends on the methane and CO2 exchange processes of Toolik Lake, Alaska. Frontiers in Environmental Science, 10, 948529.
dc.identifier.doi 10.3389/fenvs.2022.948529
dc.identifier.uri https://hdl.handle.net/1912/65886
dc.publisher Frontiers Media
dc.relation.uri https://doi.org/10.3389/fenvs.2022.948529
dc.rights Creative Commons Attribution 4.0
dc.rights.uri https://creativecommons.org/licenses/by/4.0/
dc.subject Toolik Lake
dc.subject Long-term ecological research
dc.subject LTER
dc.subject Methane flux
dc.subject Carbon dioxide flux
dc.subject Piston velocity
dc.subject Arctic trends
dc.subject Quantile regression
dc.title Effects of long-term climate trends on the methane and CO2 exchange processes of Toolik Lake, Alaska
dc.type Article
dspace.entity.type Publication
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relation.isAuthorOfPublication.latestForDiscovery 5e049ea6-384b-48b3-b48b-01bb33efab3e
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