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  • 1.
    Bastviken, David
    et al.
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Nygren, Jonatan
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Schenk, Jonathan
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Parellada Massana, Roser
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Nguyen, Thanh Duc
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Technical note: Facilitating the use of low-cost methane (CH4) sensors in flux chambers - calibration, data processing, and an open-source make-it-yourself logger2020In: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 17, no 13, p. 3659-3667Article in journal (Refereed)
    Abstract [en]

    A major bottleneck regarding the efforts to better quantify greenhouse gas fluxes, map sources and sinks, and understand flux regulation is the shortage of low-cost and accurate-enough measurement methods. The studies of methane (CH4) - a long-lived greenhouse gas increasing rapidly but irregularly in the atmosphere for unclear reasons, and with poorly understood source-sink attribution - suffer from such method limitations. This study presents new calibration and data processing approaches for use of a low-cost CH4 sensor in flux chambers. Results show that the change in relative CH4 levels can be determined at rather high accuracy in the 2-700 ppm mole fraction range, with modest efforts of collecting reference samples in situ and without continuous access to expensive reference instruments. This opens possibilities for more affordable and time-effective measurements of CH4 in flux chambers. To facilitate such measurements, we also provide a description for building and using an Arduino logger for CH4, carbon dioxide (CO2), relative humidity, and temperature.

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  • 2.
    Bastviken, David
    et al.
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Nygren, Jonathan
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Schenk, Jonathan
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Parellada Massana, Roser
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Nguyen, Thanh Duc
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Facilitating the use of low-cost methane (CH4) sensors in flux chambers: calibration, data processing, and describing an open source make-it-yourself logger2019Data set
    Download full text (zip)
    Facilitating the use of low-cost methane (CH4) sensors in flux chambers: calibration, data processing, and describing an open source make-it-yourself logger
  • 3.
    Pajala, Gustav
    et al.
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Rudberg, David
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Thematic Studies, Tema Environmental Change.
    Gålfalk, Magnus
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Melack, John Michael
    University of California, Santa Barbara, CA, United States.
    Macintyre, Sally
    University of California, Santa Barbara, CA, United States.
    Karlsson, Jan
    Umeå University, Umeå, Sweden.
    Sawakuchi, Henrique Oliveira
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Schenk, Jonathan
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Sieczko, Anna Katarzyna
    Linköping University, Department of Physics, Chemistry and Biology, Ecological and Environmental Modeling. Linköping University, Faculty of Science & Engineering.
    Sundgren, Ingrid
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Nguyen, Thanh Duc
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Bastviken, David
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Source data for ” Higher apparent gas transfer velocities for CO2 compared to CH4 in small lakes”2023Data set
    Download full text (xlsx)
    dataset
  • 4.
    Pajala, Gustav
    et al.
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Rudberg, David
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Gålfalk, Magnus
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Melack, John Michael
    Univ Calif Santa Barbara, CA 93117 USA; Univ Calif Santa Barbara, CA 93106 USA.
    Macintyre, Sally
    Univ Calif Santa Barbara, CA 93117 USA; Univ Calif Santa Barbara, CA 93106 USA; Univ Calif Santa Barbara, CA 93117 USA.
    Karlsson, Jan
    Umea Univ, Sweden.
    Sawakuchi, Henrique
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Schenk, Jonathan
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Sieczko, Anna
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Sundgren, Ingrid
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Nguyen, Thanh Duc
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Bastviken, David
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Higher Apparent Gas Transfer Velocities for CO2 Compared to CH4 in Small Lakes2023In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 57, no 23, p. 8578-8587Article in journal (Refereed)
    Abstract [en]

    Highergas transfer velocities for CO2 than CH4 inlakes challenge previous results and commonly made assumptionsand highlight the importance of gas-specific transport in aquaticgreenhouse gas exchange. Large greenhousegas emissions occur via the release of carbondioxide (CO2) and methane (CH4) from the surfacelayer of lakes. Such emissions are modeled from the air-watergas concentration gradient and the gas transfer velocity (k). The links between k and the physicalproperties of the gas and water have led to the development of methodsto convert k between gases through Schmidt numbernormalization. However, recent observations have found that such normalizationof apparent k estimates from field measurements canyield different results for CH4 and CO2. Weestimated k for CO2 and CH4 from measurements of concentration gradients and fluxes in fourcontrasting lakes and found consistently higher (on an average 1.7times) normalized apparent k values for CO2 than CH4. From these results, we infer that several gas-specificfactors, including chemical and biological processes within the watersurface microlayer, can influence apparent k estimates.We highlight the importance of accurately measuring relevant air-watergas concentration gradients and considering gas-specific processeswhen estimating k.

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  • 5.
    Pajala, Gustav
    et al.
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Sawakuchi, Henrique Oliveira
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Rudberg, David
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Thematic Studies, Tema Environmental Change.
    Schenk, Jonathan
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Sieczko, Anna Katarzyna
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Seekell, David
    Sundgren, Ingrid
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Nguyen, Thanh Duc
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Science & Engineering.
    Karlsson, Jan
    Umeå University.
    Bastviken, David
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Source data for “The effects of water column dissolved oxygen concentrations on lake methane emissions: Results from a whole-lake oxygenation experiment”2022Data set
    Download full text (xlsx)
    dataset version 2.0
  • 6.
    Pajala, Gustav
    et al.
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Sawakuchi, Henrique
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Rudberg, David
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Schenk, Jonathan
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Sieczko, Anna
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Gålfalk, Magnus
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Seekell, David
    Umea Univ, Sweden.
    Sundgren, Ingrid
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Nguyen, Thanh Duc
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Karlsson, Jan
    Umea Univ, Sweden.
    Bastviken, David
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    The Effects of Water Column Dissolved Oxygen Concentrations on Lake Methane Emissions-Results From a Whole-Lake Oxygenation Experiment2023In: Journal of Geophysical Research - Biogeosciences, ISSN 2169-8953, E-ISSN 2169-8961, Vol. 128, no 11, article id e2022JG007185Article in journal (Refereed)
    Abstract [en]

    Lakes contribute 9%-19% of global methane (CH4) emissions to the atmosphere. Dissolved molecular oxygen (DO) in lakes can inhibit the production of CH4 and promote CH4 oxidation. DO is therefore often considered an important regulator of CH4 emissions from lakes. Presence or absence of DO in the water above the sediments can affect CH4 production and emissions by (a) influencing if methane production can be fueled by the most reactive organic matter in the top sediment layer or rely on deeper and less degradable organic matter, and (b) enabling CH4 accumulation in deep waters and potentially large emissions upon water column turnover. However, the relative importance of these two DO effects on CH4 fluxes is still unclear. We assessed CH4 fluxes from two connected lake basins in northern boreal Sweden where one was experimentally oxygenated. Results showed no clear difference in summer CH4 emissions attributable to water column DO concentrations. Large amounts of CH4 accumulated in the anoxic hypolimnion of the reference basin but little of this may have been emitted because of incomplete mixing, and effective methane oxidation of stored CH4 reaching oxic water layers. Accordingly, <= 24% of the stored CH4 was likely emitted in the experimental lake. Overall, our results suggest that hypolimnetic DO and water column CH4 storage might have a smaller impact on CH4 emissions in boreal forest lakes than previous estimates, yet potential fluxes associated with water column turnover events remain a significant uncertainty in lake CH4 emission estimates.

  • 7.
    Rudberg, David
    et al.
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Duc, N. T.
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Schenk, Jonathan
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Sieczko, Anna Katarzyna
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Pajala, Gustav
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Sawakuchi, Henrique Oliveira
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences. Department of Ecology and Environmental Sciences, Umeå Universitet, Umeå, Sweden.
    Verheijen, H. A.
    Department of Ecology and Environmental Sciences, Umeå Universitet, Umeå, Sweden.
    Melack, J. M.
    Department of Ecology, Evolution, and Marine Biology, University of California Santa Barbara, Santa Barbara, CA, USA University of California Santa Barbara, Earth Research Institute, Santa Barbara, CA, USA.
    MacIntyre, S.
    Department of Ecology, Evolution, and Marine Biology, University of California Santa Barbara, Santa Barbara, CA, USA University of California Santa Barbara, Earth Research Institute, Santa Barbara, CA, USA University of California Santa Barbara, Marine Science Institute, Santa Barbara, CA, USA.
    Karlsson, J.
    Department of Ecology and Environmental Sciences, Umeå Universitet, Umeå, Sweden.
    Bastviken, David
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Diel Variability of CO2 Emissions From Northern Lakes2021In: Journal of Geophysical Research - Biogeosciences, ISSN 2169-8953, E-ISSN 2169-8961, Vol. 126, no 10, article id e2021JG006246Article in journal (Refereed)
    Abstract [en]

    Lakes are generally supersaturated in carbon dioxide (CO2) and emitters of CO2 to the atmosphere. However, estimates of CO2 flux (FCO2) from lakes are seldom based on direct flux measurements and usually do not account for nighttime emissions, yielding risk of biased assessments. Here, we present direct FCO2 measurements from automated floating chambers collected every 2-3 hr and spanning 115 24 hr periods in three boreal lakes during summer stratification and before and after autumn mixing in the most eutrophic lake of these. We observed 40%-67% higher mean FCO2 in daytime during periods of surface water CO2 supersaturation in all lakes. Day-night differences in wind speed were correlated with the day-night FCO2 differences in the two larger lakes, but in the smallest and most wind-sheltered lake peaks of FCO2 coincided with low-winds at night. During stratification in the eutrophic lake, CO2 was near equilibrium and diel variability of FCO2 insignificant, but after autumn mixing FCO2 was high with distinct diel variability making this lake a net CO2 source on an annual basis. We found that extrapolating daytime measurements to 24 hr periods overestimated FCO2 by up to 30%, whereas extrapolating measurements from the stratified period to annual rates in the eutrophic lake underestimated FCO2 by 86%. This shows the importance of accounting for diel and seasonal variability in lake CO2 emission estimates.

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  • 8.
    Rudberg, David
    et al.
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Schenk, Jonathan
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Pajala, Gustav
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Sawakuchi, Henrique
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Sieczko, Anna
    Linköping University, Department of Physics, Chemistry and Biology, Ecological and Environmental Modeling. Linköping University, Faculty of Science & Engineering.
    Sundgren, Ingrid
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Nguyen, Thanh Duc
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Karlsson, Jan
    Umea Univ, Sweden.
    Macintyre, Sally
    Univ Calif Santa Barbara, CA USA.
    Melack, John
    Univ Calif Santa Barbara, CA USA.
    Bastviken, David
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Contribution of gas concentration and transfer velocity to CO2 flux variability in northern lakes2024In: Limnology and Oceanography, ISSN 0024-3590, E-ISSN 1939-5590Article in journal (Refereed)
    Abstract [en]

    The CO( 2)flux (FCO2) from lakes to the atmosphere is a large component of the global carbon cycle anddepends on the air-water CO2concentration gradient (Delta CO2) and the gas transfer velocity (k). Both Delta CO2 and k can vary on multiple timescales and understanding their contributions toFCO(2)is important for explaining var-iability influxes and developing optimal sampling designs. We measuredFCO2 and Delta CO(2 )and derivedkforone full ice-free period in 18 lakes usingfloating chambers and estimated the contributions of Delta CO2 and k to FCO2 variability. Generally, kcontributed more than Delta CO2to short-term (1-9d) FCO2 variability. With in creased temporal period, the contribution of k to FCO2 variability decreased, and in some lakes resulted in Delta CO2 contrib-uting more thank to FCO2 variability over the full ice-free period. Increased contribution of Delta CO2 to FCO2 vari-ability over time occurred across all lakes but was most apparent in large-volume southern-boreal lakes and indeeper (>2m) parts of lakes, whereaskwas linked to FCO(2 )variability in shallow waters. Accordingly, knowing the variability of bothk and Delta CO(2 )over time and space is needed for accurate modeling of F CO2 from these vari-ables. We conclude that priority in FCO(2 )assessments should be given to direct measurements of FCO2 at multiplesites when possible, or otherwise from spatially distributed measurements of Delta CO(2 )combined with k- models that incorporate spatial variability of lake thermal structure and meteorology.

  • 9.
    Rudberg, David
    et al.
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Thematic Studies, Tema Environmental Change.
    Thanh Duc, Nguyen
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Science & Engineering.
    Schenk, Jonathan
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Sieczko, Anna Katarzyna
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Biology. Linköping University, Faculty of Science & Engineering.
    Gustav, Pajala
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Sawakuchi, Henrique Oliveira
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Verheijen, Hendricus
    Institutionen för ekologi, miljö och geovetenskap, Umeå Universitet, Umeå.
    Melak, John
    Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, California, US; Earth Research Institute, University of California, Santa Barbara, California, USA .
    MacIntyre, Sally
    Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, California, US; Earth Research Institute, University of California, Santa Barbara, California, USA; Marine Science Institute, University of California, Santa Barbara, California, USA .
    Karlsson, Jan
    Institutionen för ekologi, miljö och geovetenskap, Umeå Universitet, Umeå.
    Bastviken, David
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Source data for "Diel variability of CO2 emissions from Northern lakes and the effect of lake mixing"2020Data set
    Download full text (xlsx)
    dataset
  • 10. Order onlineBuy this publication >>
    Schenk, Jonathan
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Methane dynamics in northern lakes: Insights from multi-scale observations2022Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Methane (CH4) is a potent greenhouse gas which is emitted to the atmosphere from both natural and anthropogenic sources. Current evidence indicates that lakes account for a large part of the global emissions of CH4, but their contribution is difficult to quantify because of large temporal and spatial variability in processes leading to CH4 fluxes from lakes to the atmosphere. Making sense of the complexity and variability of CH4 emissions from lakes requires observations covering the range of temporal and spatial scales at which these processes occur, both within and between lakes. Northern regions are of particular interest for such studies because they contain a larger number of lakes than any other region in the world and they are disproportionately affected by climate change, with possible consequences for future CH4 emissions.

    The aim of this thesis was to investigate patterns of CH4 dynamics and emissions in several lakes distributed in different climatic regions of Sweden, paying particular attention to spatial and temporal variability of CH4 fluxes and concentrations. Fluxes, concentrations, carbon stable isotope signature of CH4, and a range of commonly monitored lake characteristics were measured several times during one year at multiple locations in each lake. The measurements provided an extensive set of observations of CH4 concentrations and fluxes in lakes, together with possible environmental drivers. These observations were then used to investigate patterns of CH4 dynamics in northern lakes and to assess the ability of empirical and process-based models to predict CH4 concentrations and fluxes in lakes.

    The results indicate that simple empirical models, consisting of linear regressions between explanatory variables and CH4 fluxes and concentrations averaged over the lake surface and ice-free period of the year, can be useful in some specific cases (for example describing ebullitive fluxes from total phosphorus or chlorophyll a concentrations). However, it was also noted that using such models for extrapolation can lead to large errors, especially if the observations do not account for temporal and spatial variability of CH4 fluxes and concentrations. An example of high variability was seen in day-night measurements of CH4 fluxes in four lakes over several months. To try to compensate for some of the shortcomings of empirical models, an established process-based and one-dimensional lake model was used to simulate CH4 concentration in the water column of the studied lakes. Predictions were in good agreement with observations in several of the investigated lakes, considering that the model was not pre-calibrated for any of the lake specifically. However, it was also clear that there can be key processes that require specific consideration in process-based models, and some degree of simplification is needed, especially when detailed information on the modelled systems is not available. The simplifications and assumptions that need to be made can be informed by the study and observation of relevant processes in situ. For example, groundwater was found to potentially contribute a major part of CH4 stored in one small boreal lake using measurements of stable isotope signature of CH4 in littoral sediment and deep water of that lake, as well as in the groundwater in the mire next to it. Stable isotope measurements in five other lakes also revealed consistent differences in CH4 sources to the surface and deep zones of lakes when they are separated by thermal stratification of the water column. Such knowledge could be used in the design of numerical models of lakes with the objective to improve predictions of current and future emissions of CH4 from these environments.

    Overall, this thesis contributes to the current knowledge on assessment of CH4 emissions from lakes at several temporal and spatial scales. It also emphasizes critical aspects which must be considered to reduce bias in future empirical and process-based models of CH4 in lakes.

    List of papers
    1. Diel variability of methane emissions from lakes
    Open this publication in new window or tab >>Diel variability of methane emissions from lakes
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    2020 (English)In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 117, no 35, p. 21488-21494Article in journal (Refereed) Published
    Abstract [en]

    Lakes are considered the second largest natural source of atmospheric methane (CH4). However, current estimates are still uncertain and do not account for diel variability of CH4 emissions. In this study, we performed high-resolution measurements of CH4 flux from several lakes, using an automated and sensor-based flux measurement approach (in total 4,580 measurements), and demonstrated a clear and consistent diel lake CH4 flux pattern during stratification and mixing periods. The maximum of CH4 flux were always noted between 10:00 and 16:00, whereas lower CH4 fluxes typically occurred during the nighttime (00:00-04:00). Regardless of the lake, CH4 emissions were on an average 2.4 higher during the day compared to the nighttime. Fluxes were higher during daytime on nearly 80% of the days. Accordingly, estimates and extrapolations based on daytime measurements only most likely result in overestimated fluxes, and consideration of diel variability is critical to properly assess the total lake CH4 flux, representing a key component of the global CH4 budget. Hence, based on a combination of our data and additional literature information considering diel variability across latitudes, we discuss ways to derive a diel variability correction factor for previous measurements made during daytime only.

    Place, publisher, year, edition, pages
    Washington, DC 20001 United States: NATL ACAD SCIENCES, 2020
    Keywords
    methane fluxes; diel variability; automated flux chambers; lake greenhouse gas emissions
    National Category
    Physical Geography
    Identifiers
    urn:nbn:se:liu:diva-170661 (URN)10.1073/pnas.2006024117 (DOI)000572974300014 ()32817550 (PubMedID)2-s2.0-85090508855 (Scopus ID)
    Note

    Funding Agencies|European Research Council under the European Unions Horizon 2020 research and innovation programmeEuropean Research Council (ERC) [725546]; Swedish Research CouncilSwedish Research Council [2016-04829]; FORMAS (Swedish research council for sustainable development) [2018-01794]; Knut and Alice Wallenberg FoundationKnut & Alice Wallenberg Foundation [2016.0083]

    Available from: 2020-10-19 Created: 2020-10-19 Last updated: 2022-05-18Bibliographically approved
    2. Methane in Lakes: Variability in Stable Carbon Isotopic Composition and the Potential Importance of Groundwater Input
    Open this publication in new window or tab >>Methane in Lakes: Variability in Stable Carbon Isotopic Composition and the Potential Importance of Groundwater Input
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    2021 (English)In: Frontiers in Earth Science, E-ISSN 2296-6463, Vol. 9, article id 722215Article in journal (Refereed) Published
    Abstract [en]

    Methane (CH4) is an important component of the carbon (C) cycling in lakes. CH4 production enables carbon in sediments to be either reintroduced to the food web via CH4 oxidation or emitted as a greenhouse gas making lakes one of the largest natural sources of atmospheric CH4. Large stable carbon isotopic fractionation during CH4 oxidation makes changes in 13C:12C ratio (δ13C) a powerful and widely used tool to determine the extent to which lake CH4 is oxidized, rather than emitted. This relies on correct δ13C values of original CH4 sources, the variability of which has rarely been investigated systematically in lakes. In this study, we measured δ13C in CH4 bubbles in littoral sediments and in CH4 dissolved in the anoxic hypolimnion of six boreal lakes with different characteristics. The results indicate that δ13C of CH4 sources is consistently higher (less 13C depletion) in littoral sediments than in deep waters across boreal and subarctic lakes. Variability in organic matter substrates across depths is a potential explanation. In one of the studied lakes available data from nearby soils showed correspondence between δ13C-CH4 in groundwater and deep lake water, and input from the catchment of CH4 via groundwater exceeded atmospheric CH4 emissions tenfold over a period of 1 month. It indicates that lateral hydrological transport of CH4 can explain the observed δ13C-CH4 patterns and be important for lake CH4 cycling. Our results have important consequences for modelling and process assessments relative to lake CH4 using δ13C, including for CH4 oxidation, which is a key regulator of lake CH4 emissions.

    Place, publisher, year, edition, pages
    Lausanne, Switzerland: Frontiers Media S.A., 2021
    Keywords
    General Earth and Planetary Sciences, stable carbon isotope, methane, lake, groundwater, endmember
    National Category
    Environmental Sciences
    Identifiers
    urn:nbn:se:liu:diva-181136 (URN)10.3389/feart.2021.722215 (DOI)000717647200001 ()2-s2.0-85118920484 (Scopus ID)
    Funder
    EU, European Research CouncilSwedish Research CouncilSwedish Research Council FormasKnut and Alice Wallenberg Foundation
    Note

    Funding: European Research Council (ERC) under the European Unions Horizon 2020 research and innovation programmeEuropean Research Council (ERC) [725546]; Swedish Research CouncilSwedish Research CouncilEuropean Commission [201604829]; FORMASSwedish Research Council Formas [2018-01794]; Knut and Alice Wallenberg FoundationKnut & Alice Wallenberg Foundation [2016.0083]

    Available from: 2021-11-17 Created: 2021-11-17 Last updated: 2023-08-28Bibliographically approved
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  • 11.
    Schenk, Jonathan
    et al.
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Sawakuchi, Henrique Oliveira
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Sieczko, Anna Katarzyna
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Pajala, Gustav
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Rudberg, David
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Hagberg, Emelie
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Fors, Kjell
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Laudon, Hjalmar
    Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden.
    Karlsson, Jan
    Department of Ecology and Environmental Science, Climate Impacts Research Centre, Umeå University, Umeå, Sweden.
    Bastviken, David
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Data associated with the manuscript "Methane in Lakes: Variability in Stable Carbon Isotopic Composition and the Potential Importance of Groundwater Input"2021Data set
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    data set 3
  • 12.
    Schenk, Jonathan
    et al.
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Sawakuchi, Henrique Oliveira
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Sieczko, Anna Katarzyna
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Pajala, Gustav
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Rudberg, David
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Hagberg, Emelie
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Fors, Kjell
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Laudon, Hjalmar
    Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden.
    Karlsson, Jan
    Climate Impacts Research Centre, Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden.
    Bastviken, David
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Methane in Lakes: Variability in Stable Carbon Isotopic Composition and the Potential Importance of Groundwater Input2021In: Frontiers in Earth Science, E-ISSN 2296-6463, Vol. 9, article id 722215Article in journal (Refereed)
    Abstract [en]

    Methane (CH4) is an important component of the carbon (C) cycling in lakes. CH4 production enables carbon in sediments to be either reintroduced to the food web via CH4 oxidation or emitted as a greenhouse gas making lakes one of the largest natural sources of atmospheric CH4. Large stable carbon isotopic fractionation during CH4 oxidation makes changes in 13C:12C ratio (δ13C) a powerful and widely used tool to determine the extent to which lake CH4 is oxidized, rather than emitted. This relies on correct δ13C values of original CH4 sources, the variability of which has rarely been investigated systematically in lakes. In this study, we measured δ13C in CH4 bubbles in littoral sediments and in CH4 dissolved in the anoxic hypolimnion of six boreal lakes with different characteristics. The results indicate that δ13C of CH4 sources is consistently higher (less 13C depletion) in littoral sediments than in deep waters across boreal and subarctic lakes. Variability in organic matter substrates across depths is a potential explanation. In one of the studied lakes available data from nearby soils showed correspondence between δ13C-CH4 in groundwater and deep lake water, and input from the catchment of CH4 via groundwater exceeded atmospheric CH4 emissions tenfold over a period of 1 month. It indicates that lateral hydrological transport of CH4 can explain the observed δ13C-CH4 patterns and be important for lake CH4 cycling. Our results have important consequences for modelling and process assessments relative to lake CH4 using δ13C, including for CH4 oxidation, which is a key regulator of lake CH4 emissions.

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  • 13.
    Schenk, Jonathan
    et al.
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Sieczko, Anna Katarzyna
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Rudberg, David
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Thematic Studies, Tema Environmental Change.
    Pajala, Gustav
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Sawakuchi, Henrique Oliveira
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Gålfalk, Magnus
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Sundgren, Ingrid
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Thanh Duc, Nguyen
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Science & Engineering.
    Bastviken, David
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Evaluating Empirical Models of Lake Methane Emission and Surface Water Concentration across Hemiboreal to Subarctic Regions2022Data set
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    Table 1 in the corresponding manuscript
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    Table 2 in the corresponding manuscript
  • 14.
    Sieczko, Anna Katarzyna
    et al.
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Dang, Nguyen Thong
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Schenk, Jonathan
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Pajala, Gustav
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Rudberg, David
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Sawakuchi, Henrique
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences. Umea Univ, Sweden.
    Bastviken, David
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Diel variability of methane emissions from lakes2020In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 117, no 35, p. 21488-21494Article in journal (Refereed)
    Abstract [en]

    Lakes are considered the second largest natural source of atmospheric methane (CH4). However, current estimates are still uncertain and do not account for diel variability of CH4 emissions. In this study, we performed high-resolution measurements of CH4 flux from several lakes, using an automated and sensor-based flux measurement approach (in total 4,580 measurements), and demonstrated a clear and consistent diel lake CH4 flux pattern during stratification and mixing periods. The maximum of CH4 flux were always noted between 10:00 and 16:00, whereas lower CH4 fluxes typically occurred during the nighttime (00:00-04:00). Regardless of the lake, CH4 emissions were on an average 2.4 higher during the day compared to the nighttime. Fluxes were higher during daytime on nearly 80% of the days. Accordingly, estimates and extrapolations based on daytime measurements only most likely result in overestimated fluxes, and consideration of diel variability is critical to properly assess the total lake CH4 flux, representing a key component of the global CH4 budget. Hence, based on a combination of our data and additional literature information considering diel variability across latitudes, we discuss ways to derive a diel variability correction factor for previous measurements made during daytime only.

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  • 15.
    Sieczko, Anna Katarzyna
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Ecological and Environmental Modeling. Linköping University, Faculty of Science & Engineering.
    Schenk, Jonathan
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Rudberg, David
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Thematic Studies, Tema Environmental Change.
    Nguyen, Thanh Duc
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Science & Engineering.
    Pajala, Gustav
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Sawakuchi, Henrique
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Bastviken, David
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Data set associated with the manuscript submitted to Science of the Total Environment by Sieczko et.al 20232023Data set
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    Data set
  • 16.
    Sieczko, Anna
    et al.
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Schenk, Jonathan
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Rudberg, David
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Nguyen, Thanh Duc
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Pajala, Gustav
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Sawakuchi, Henrique
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Bastviken, David
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Minor impacts of rain on methane flux from hemiboreal, boreal, and subarctic lakes2023In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 895, article id 164849Article in journal (Refereed)
    Abstract [en]

    Methane (CH4) emissions (FCH4) from northern freshwater lakes are not only significant but also highly variable in time and one driver variable suggested to be important is precipitation. Rain can have various, potentially large effects on FCH4 across multiple time frames, and verifying the impact of rain on lake FCH4 is key to understand both contemporary flux regulation, and to predict future FCH4 related to possible changes in frequency and intensity of rainfall from climate change. The main objective of this study was to assess the short-term impact of typically occurring rain events with different intensity on FCH4 from various lake types located in hemiboreal, boreal, and subarctic Sweden. In spite of high time resolution automated flux measurements across different depth zones and covering numerous commonly types of rain events in northern areas, in general, no strong impact on FCH4 during and within 24 h after the rainfall could be observed. Only in deeper lake areas and during longer rain events FCH4 was weakly related to rain (R2 = 0.29, p < 0.05), where a minor FCH4 decrease during the rain was identified, suggesting that direct rainwater input, during greater rainfall, may decrease FCH4 by dilution of surface water CH4. Overall, this study indicates that typical rain events in the studied regions have minor direct short-term effects on FCH4 from northern lakes and do not enhance FCH4 from shallow and deeper parts of lakes during and up to 24-h after the rainfall. Instead, other factors such as wind speed, water temperature and pressure changes were more strongly correlated with lake FCH4.

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