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  • 1.
    Aeppli, Christoph
    et al.
    Stockholm University, Sweden .
    Bastviken, David
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Andersson, Per
    Swedish Museum Nat Hist, Sweden .
    Gustafsson, Orjan
    Stockholm University, Sweden .
    Chlorine Isotope Effects and Composition of Naturally Produced Organochlorines from Chloroperoxidases, Flavin-Dependent Halogenases, and in Forest Soil2013In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 47, no 13, p. 6864-6871Article in journal (Refereed)
    Abstract [en]

    The use of stable chlorine isotopic signatures (delta Cl-37) of organochlorine compounds has been suggested as a tool to determine both their origins and transformations in the environment. Here we investigated the delta Cl-37 fractionation of two important pathways for enzymatic natural halogenation: chlorination by chloroperoxidase (CPO) and flavin-dependent halogenases (FDH). Phenolic products of CPO were highly Cl-37 depleted (delta Cl-37 = -12.6 +/- 0.9 parts per thousand); significantly more depleted than all known industrially produced organochlorine compounds (delta Cl-37 = -7 to +6 parts per thousand). In contrast, four FDH products did not exhibit any observable isotopic shifts (delta Cl-37 = -0.3 +/- 0.6 parts per thousand). We attributed the different isotopic effect to the distinctly different chlorination mechanisms employed by the two enzymes. Furthermore, the delta Cl-37 in bulk organochlorines extracted from boreal forest soils were only slightly depleted in Cl-37 relative to inorganic Cl. In contrast to previous suggestions that CPO plays a key role in production of soil organochlorines, this observation points to the additional involvement of either other chlorination pathways, or that dechlorination of naturally produced organochlorines can neutralize delta Cl-37 shifts caused by CPO chlorination. Overall, this study demonstrates that chlorine isotopic signatures are highly useful to understand sources and cycling of organochlorines in nature. Furthermore, this study presents delta Cl-37 values of FDH products as well of bulk organochlorines extracted from pristine forest soil for the first time.

  • 2.
    Aeppli, Christoph
    et al.
    Stockholm University.
    Holmstrand, Henry
    Stockholm University.
    Bastviken, David
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Tysklind, Mats
    Umeå University.
    Gustafsson, Orjan
    Stockholm University.
    Investigating formation and degradation of polychlorinated phenols in the environment using chlorine and carbon stable isotope fractionation in ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, vol 242, issue , pp2011In: ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, AMER CHEMICAL SOC, 1155 16TH ST, NW, WASHINGTON, DC 20036 USA , 2011, Vol. 242Conference paper (Refereed)
    Abstract [en]

    n/a

  • 3.
    Andersson, Anna
    et al.
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Ashiq, Muhammad Jamshaid
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Shoeb, Mohammad
    Department of Chemistry, University of Dhaka, Dhaka, Bangladesh.
    Karlsson, Susanne
    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.
    Kylin, Henrik
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences. Research Unit: Environmental Sciences and Management, North-West University, Potchefstroom, South Africa.
    Evaluating gas chromatography with a halogen-specific detector for the determination of disinfection by-products in drinking water2019In: Environmental Science and Pollution Research, ISSN 0944-1344, E-ISSN 1614-7499, Vol. 26, p. 7305-7314Article in journal (Refereed)
    Abstract [en]

    The occurrence of disinfection by-products (DBPs) in drinking water has become an issue of concern during the past decades. The DBPs pose health risks and are suspected to cause various cancer forms, be genotoxic and have negative developmental effects. The vast chemical diversity of DBPs makes comprehensive monitoring challenging. Only few of the DBPs are regulated and included in analytical protocols. In this study, a method for simultaneous measurement of 20 DBPs from five different structural classes (both regulated and non-regulated) was investigated and further developed for 11 DBPs using solid phase extraction and gas chromatography coupled with a halogen specific detector (XSD). The XSD was highly selective towards halogenated DBPs, providing chromatograms with little noise. The method allowed detection down to 0.05 µg/L and showed promising results for the simultaneous determination of a range of neutral DBP classes. Compounds from two classes of emerging DBPs, more cytotoxic than the “traditional” regulated DBPs, were successfully determined using this method. However, haloacetic acids (HAAs) should be analyzed separately as some HAA methyl esters may degrade giving false positives of trihalomethanes (THMs). The method was tested on real water samples from two municipal waterworks where the target DBP concentrations were found below the regulatory limits of Sweden.

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    Evaluating gas chromatography with a halogen-specific detectorfor the determination of disinfection by-products in drinking water
  • 4.
    Andersson, Anna
    et al.
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Gonsior, Michael
    Univ Maryland, MD 20688 USA.
    Harir, Mourad
    German Res Ctr Hlth & Environm, Germany; Tech Univ Munich, Germany.
    Hertkorn, Norbert
    German Res Ctr Hlth & Environm, Germany.
    Schmitt-Kopplin, Philippe
    German Res Ctr Hlth & Environm, Germany; Tech Univ Munich, Germany.
    Powers, Leanne
    Univ Maryland, MD 20688 USA.
    Kylin, Henrik
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences. North West Univ, South Africa.
    Hellstrom, Daniel
    Norrvatten, Sweden.
    Nilsson, Kerstin
    VA SYD, Sweden.
    Pettersson, Amma
    Nodra, Sweden.
    Stavklint, Helena
    Tekniska Verken Linkoping AB Publ, SE-58115 Linkoping, Sweden.
    Bastviken, David
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Molecular changes among non-volatile disinfection by-products between drinking water treatment and consumer taps2021In: Environmental Science: Water Research & Technology, ISSN 2053-1400, E-ISSN 2053-1419, Vol. 7, no 12, p. 2335-2345Article in journal (Refereed)
    Abstract [en]

    The formation of disinfection by-products (DBPs) during drinking water treatment has been associated with various health concerns but the total DBP exposure is still unknown. In this study, molecular level non-target analysis by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was used to study non-volatile DBPs, and how their composition changes during water distribution in four drinking water treatment plants (DWTPs) in Sweden using different types of raw water and disinfection processes. The largest portion of tap water DBP compositions were detected also at the DWTPs, highlighting that these DBP formulae were rather stable and contribute to human DBP exposure. Yet the number of detected DBPs decreased 14-48% between drinking water treatment and consumer taps in the three plants in which no mixing of water from other DWTPs in the distribution system occurred showing active DBP processing in the water distribution network. While considerable amounts of bromine-containing DBPs were detected upon chemical disinfection in some DWTPs, few of them were detected in the tap water samples, likely due to debromination by hydrolytic reactions. The overall fewer non-volatile DBPs detected in tap waters, along with changed distribution among chlorine and bromine DBPs, demonstrate that DBP mixtures are highly dynamic and that DBP measurements at DWTPs do not adequately reflect exposure at the point-of-use. Clearly, more knowledge about changes of DBP mixtures through the distribution system is needed to improve DBP exposure assessments.

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  • 5.
    Andersson, Anna
    et al.
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Thematic Studies, Tema Environmental Change.
    Harir, Mourad
    Research Unit Analytical Biogeochemistry, Helmholtz Zentrum München, Ingolstaedter Landstrasse 1, 85764, Neuherberg, Germany ; Analytical Food Chemistry, Technical University Munich, Maximus-von-Imhof-Forum 2, 85354, Freising, Germany.
    Bastviken, David
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Thematic Studies, Tema Environmental Change.
    Extending the potential of Fourier transform ion cyclotron resonance massspectrometry for the analysis of disinfection by-products2023In: TrAC. Trends in analytical chemistry, ISSN 0165-9936, E-ISSN 1879-3142, Vol. 167, article id 117264Article, review/survey (Refereed)
    Abstract [en]

    Potentially harmful disinfection by-products (DBPs) are formed upon drinking water treatment when disinfectantsreact with organic matter in the water. Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) provides information on the compositions of individual DBPs in the unknown, toxicologically relevantfraction, comprising non-volatile, high-molecular weight DBPs. This review evaluates current applications of FTICR-MS for DBP analysis to assist improved analysis with this technique. Four methodological aspects are infocus, 1) The use of quenching agents, 2) The choice of extraction method 3) The choice of ionization techniques/modes, and 4) Data processing including DBP formula verification and interpretation. Quenching can lead todecomposition or adduct formation and needs to be further evaluated or avoided. There is a large potential toexpand FT-ICR-MS DBP analysis by applying different SPE sorbents and ionization techniques, and improvedsystematic verification procedures are important to ensure reliable non-target analysis.

  • 6.
    Andersson, Anna
    et al.
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Harir, Mourad
    Helmholtz Zentrum München, Germany.
    Gonsior, Michael
    University of Maryland Center for Environmental Science, USA.
    Hertkorn, Norbert
    Helmholtz Zentrum München, Germany.
    Schmitt-Kopplin, Philippe
    Helmholtz Zentrum München, Germany.
    Kylin, Henrik
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Karlsson, Susanne
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Ashiq, Muhammad Jamshaid
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Lavonen, Elin
    Norrvatten, Kvalitet och Utveckling.
    Nilsson, Kerstin
    VA SYD.
    Pettersson, Ämma
    Nodra.
    Stavklint, Helena
    Tekniska verken i Linköping.
    Bastviken, David
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Waterworks-specific composition of drinking water disinfection by-products2019In: Environmental Science: Water Research & Technology, ISSN 2053-1400, E-ISSN 2053-1419, no 5, p. 861-872Article in journal (Refereed)
    Abstract [en]

    Reactions between chemical disinfectants and natural organic matter (NOM) upon drinking water treatment result in formation of potentially harmful disinfection by-products (DBPs). The diversity of DBPs formed is high and a large portion remains unknown. Previous studies have shown that non-volatile DBPs are important, as much of the total toxicity from DBPs has been related to this fraction. To further understand the composition and variation of DBPs associated with this fraction, non-target analysis with ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was employed to detect DBPs at four Swedish waterworks using different types of raw water and treatments. Samples were collected five times covering a full year. A common group of DBPs formed at all four waterworks was detected, suggesting a similar pool of DBP precursors in all raw waters that might be related to phenolic moieties. However, the largest proportion (64–92%) of the assigned chlorinated and brominated molecular formulae were unique, i.e. were solely found in one of the four waterworks. In contrast, the compositional variations of NOM in the raw waters and samples collected prior to chemical disinfection were rather limited.This indicated that waterworks-specific DBPs presumably originated from matrix effects at the point of disinfection, primarily explained by differences in bromide levels, disinfectants (chlorine versus chloramine) and different relative abundances of isomers among the NOM compositions studied. The large variation of observed DBPs in the toxicologically relevant non-volatile fraction indicates that non-targeted monitoring strategies might be valuable to ensure relevant DBP monitoring in the future.

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    Waterworks-specific composition of drinking water disinfection by-products
  • 7.
    Andersson, Anna
    et al.
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Lavonen, Elin
    Norrvatten, Sweden; Stockholm Vatten and Avfall, Sweden.
    Harir, Mourad
    Helmholtz Ctr Munich, Germany; Tech Univ Munich, Germany.
    Gonsior, Michael
    Univ Maryland, MD 20688 USA.
    Hertkorn, Norbert
    Helmholtz Ctr Munich, Germany.
    Schmitt-Kopplin, Philippe
    Helmholtz Ctr Munich, Germany; Tech Univ Munich, Germany.
    Kylin, Henrik
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences. North West Univ, South Africa.
    Bastviken, David
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Selective removal of natural organic matter during drinking water production changes the composition of disinfection by-products2020In: Environmental Science: Water Research & Technology, ISSN 2053-1400, E-ISSN 2053-1419, Vol. 6, no 3, p. 779-794Article in journal (Refereed)
    Abstract [en]

    Disinfection by-products (DBPs) are potentially toxic compounds formed upon chemical disinfection of drinking water. Controlling the levels and characteristics of dissolved organic matter (DOM) as precursor material for DBPs is a major target to reduce DBP formation. A pilot-scale treatment including suspended ion exchange (SIX (R)), a ceramic microfilter (CeraMac (R)) with in-line coagulation and optional pre-ozonation followed by granular activated carbon (GAC) filtration was compared with a conventional full-scale treatment based on DOM removal and DBP formation using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), rapid fractionation, liquid chromatography organic carbon detection (LC-OCD), adsorbable organic halogens (AOX) and trihalomethane (THM) analysis. The new treatment combination showed different selectivity for DOM removal, compared to the conventional, leading to changes in composition of the DBPs formed. SIX (R) and GAC had the largest impacts on reducing AOX and THM formation potentials but the high adsorptive capacity of GAC affected the diversity of detected DBPs most. Chlorination and chloramination of pilot treated water with doses normally used in Sweden produced low levels of AOX compared to the full-scale treatment, but FT-ICR MS revealed an abundance of brominated DBP species in contrast with the conventional treatment, which were dominated by chlorinated DBPs. This finding was largely linked to the high DOM removal by the pilot treatment, causing an increased Br-/C ratio and a higher formation of HOBr. Potential increases in Br-DBPs are important to consider in minimizing health risks associated with DBPs, because of the supposed higher toxicity of Br-DBPs compared to Cl-DBPs.

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  • 8.
    Audet, Joachim
    et al.
    Aarhus Univ, Denmark; Swedish Univ Agr Sci, Sweden.
    Bastviken, David
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Bundschuh, Mirco
    Swedish Univ Agr Sci, Sweden; Univ Koblenz Landau, Germany.
    Buffam, Ishi
    Univ Cincinnati, OH USA.
    Feckler, Alexander
    Swedish Univ Agr Sci, Sweden.
    Klemedtsson, Leif
    Univ Gothenburg, Sweden.
    Laudon, Hjalmar
    Swedish Univ Agr Sci, Sweden.
    Loefgren, Stefan
    Swedish Univ Agr Sci, Sweden.
    Balathandayuthabani, Sivakiruthika
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Oquist, Mats
    Swedish Univ Agr Sci, Sweden.
    Peacock, Mike
    Swedish Univ Agr Sci, Sweden.
    Wallin, Marcus B.
    Uppsala Univ, Sweden.
    Forest streams are important sources for nitrous oxide emissions2020In: Global Change Biology, ISSN 1354-1013, E-ISSN 1365-2486, Vol. 26, no 2, p. 629-641Article in journal (Refereed)
    Abstract [en]

    Streams and river networks are increasingly recognized as significant sources for the greenhouse gas nitrous oxide (N2O). N2O is a transformation product of nitrogenous compounds in soil, sediment and water. Agricultural areas are considered a particular hotspot for emissions because of the large input of nitrogen (N) fertilizers applied on arable land. However, there is little information on N2O emissions from forest streams although they constitute a major part of the total stream network globally. Here, we compiled N2O concentration data from low-order streams (~1,000 observations from 172 stream sites) covering a large geographical gradient in Sweden from the temperate to the boreal zone and representing catchments with various degrees of agriculture and forest coverage. Our results showed that agricultural and forest streams had comparable N2O concentrations of 1.6 +/- 2.1 and 1.3 +/- 1.8 mu g N/L, respectively (mean +/- SD) despite higher total N (TN) concentrations in agricultural streams (1,520 +/- 1,640 vs. 780 +/- 600 mu g N/L). Although clear patterns linking N2O concentrations and environmental variables were difficult to discern, the percent saturation of N2O in the streams was positively correlated with stream concentration of TN and negatively correlated with pH. We speculate that the apparent contradiction between lower TN concentration but similar N2O concentrations in forest streams than in agricultural streams is due to the low pH (amp;lt;6) in forest soils and streams which affects denitrification and yields higher N2O emissions. An estimate of the N2O emission from low-order streams at the national scale revealed that ~1.8 x 10(9) g N2O-N are emitted annually in Sweden, with forest streams contributing about 80% of the total stream emission. Hence, our results provide evidence that forest streams can act as substantial N2O sources in the landscape with 800 x 10(9) g CO2-eq emitted annually in Sweden, equivalent to 25% of the total N2O emissions from the Swedish agricultural sector.

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  • 9.
    Backstrand, K.
    et al.
    Stockholm University.
    Crill, P. M.
    Stockholm University.
    Mastepanov, M.
    Lund University.
    Christensen, T. R.
    Lund University.
    Bastviken, D.
    Stockholm University.
    Non-methane volatile organic compound flux from a subarctic mire in Northern Sweden2008In: Tellus. Series B, Chemical and physical meteorology, ISSN 0280-6509, E-ISSN 1600-0889, Vol. 60, no 2, p. 226-237Article in journal (Refereed)
    Abstract [en]

    Biogenic NMVOCs are mainly formed by plants and microorganisms. They have strong impact on the local atmospheric chemistry when emitted to the atmosphere. The objective of this study was to determine if there are significant emissions of non-methane volatile organic compounds (NMVOCs) from a subarctic mire in northern Sweden. Subarctic peatlands in discontinuous permafrost regions are undergoing substantial environmental changes due to their high sensitivity to climate warming and there is need for including NMVOCs in the overall carbon budget. Automatic and manual chamber measurements were used to estimate NMVOC fluxes from three dominating subhabitats on the mire during three growing seasons. Emission rates varied and were related to plant species distribution and seasonal net ecosystem exchange of carbon dioxide. The highest fluxes were observed from wetter sites dominated by Eriophorum and Sphagnum spp. Total NMVOC emissions from the mire (similar to 17 ha) is estimated to consist of similar to 150 kgC during a growing season with 150 d. NMVOC fluxes can account for similar to 5% of total net carbon exchange (-3177 kgC) at the mire during the same period. NMVOC emissions are therefore a significant component in a local carbon budget for peatlands.

  • 10.
    Backstrand, K.
    et al.
    Stockholm University.
    Crill, P. M.
    Stockholm University.
    Mastepanov, M.
    Lund University.
    Christensen, T. R.
    Lund University.
    Bastviken, D.
    Stockholm University.
    Total hydrocarbon flux dynamics at a subarctic mire in northern Sweden2008In: Journal of Geophysical Research, ISSN 0148-0227, E-ISSN 2156-2202, Vol. 113, no G3Article in journal (Refereed)
    Abstract [en]

    This is a study of the spatial and temporal variability of total hydrocarbon (THC) emissions from vegetation and soil at a subarctic mire, northern Sweden. THCs include methane (CH4) and nonmethane volatile organic compounds (NMVOCs), both of which are atmospherically important trace gases and constitute a significant proportion of the carbon exchange between biosphere and atmosphere. Reliable characterization of the magnitude and the dynamics of the THC fluxes from high latitude peatlands are important when considering to what extent trace gas emissions from such ecosystems may change and feed back on climate regulation as a result of warmer climate and melting permafrost. High frequency measurements of THC and carbon dioxide (CO2) were conducted during four sequential growing seasons in three localities representing the trophic range of plant communities at the mire. The magnitude of the THC flux followed the moisture gradient with increasing emissions from a dry Palsa site (2.2 +/- 0.1 mgC m(-2) d(-1)), to a wet intermediate melt feature with Sphagnum spp. (28 +/- 0.3 mgC m(-2) d(-1)) and highest emissions from a wet Eriophorum spp. site (122 +/- 1.4 mgC m(-2) d(-1)) (overall mean +/- 1 SE, n = 2254, 2231 and 2137). At the Palsa site, daytime THC flux was most strongly related to air temperature while daytime THC emissions at the Sphagnum site had a stronger relation to ground temperature. THC emissions at both the wet sites were correlated to net ecosystem exchange of CO2. An overall spatial correlation indicated that areas with highly productive vegetation communities also had high THC emission potential.

  • 11.
    Balathandayuthabani, Sivakiruthika
    et al.
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences. Tamil Nadu Agr Univ, India.
    Wallin, Marcus B.
    Swedish Univ Agr Sci, Sweden.
    Klemedtsson, Leif
    Univ Gothenburg, Sweden.
    Crill, Patrick
    Stockholm Univ, Sweden; Stockholm Univ, Sweden.
    Bastviken, David
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Aquatic carbon fluxes in a hemiboreal catchment are predictable from landscape morphology, temperature, and runoff2023In: Limnology and Oceanography Letters, E-ISSN 2378-2242, E-ISSN 2378-2242, Vol. 8, no 2, p. 313-322Article in journal (Refereed)
    Abstract [en]

    Aquatic networks contribute greenhouse gases and lateral carbon (C) export from catchments. The magnitudes of these fluxes exceed the global land C sink but are uncertain. Resolving this uncertainty is important for understanding climate feedbacks. We quantified vertical methane (CH4) and carbon dioxide (CO2) emissions from lakes and streams, and lateral export of dissolved inorganic and organic carbon from a hemiboreal catchment for 3 yr. Lateral C fluxes dominated the total aquatic C flux. All aquatic C fluxes were disproportionately contributed from spatially restricted areas and/or short-term events. Hence, consideration of local and episodic variability is vital. Temperature and runoff were the main temporal drivers for lake and stream C emissions, respectively. Whole-catchment aquatic C emissions scaled linearly with these drivers within timeframes of stable land-cover. Hence, temperature and runoff increase across Northern Hemisphere humid areas from climate change may yield proportional increases in aquatic C fluxes.

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  • 12.
    Balathandayuthabani, Sivakiruthika
    et al.
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Wallin, Marcus B
    Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Sweden.
    Klemedtsson, Leif
    Department of Earth Sciences, University of Gothenburg, Sweden.
    Crill, Patrick
    Department of Geological Sciences and Bolin Centre for Climate Research, Stockholm University, Sweden.
    Bastviken, David
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Catchment-scale aquatic C emissions2020Data set
  • 13.
    Balathandayuthabani, Sivakiruthika
    et al.
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Wallin, Marcus B
    Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Sweden.
    Klemedtsson, Leif
    Department of Earth Sciences, University of Gothenburg, Sweden.
    Crill, Patrick
    Department of Geological Sciences and Bolin Centre for Climate Research, Stockholm University, Sweden.
    Bastviken, David
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Catchment-scale aquatic C emissions2022Data set
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    README
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    Daily_aquatic_lateral_C_emissions_SRC
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    Daily_aquatic_vertical_C_emissions_SRC
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    Stream_DIC_concentrations
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    Stream_DOC_concentrations
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    Stream_gas_concentrations_k_SRC
  • 14.
    Bansal, Sheel
    et al.
    US Geol Survey, ND 58401 USA.
    Creed, Irena F.
    Univ Toronto Scarborough, Canada.
    Tangen, Brian A.
    US Geol Survey, ND 58401 USA.
    Bridgham, Scott D.
    Univ Oregon, OR USA.
    Desai, Ankur R.
    Univ Wisconsin Madison, WI USA.
    Krauss, Ken W.
    US Geol Survey, LA USA.
    Neubauer, Scott C.
    Virginia Commonwealth Univ, VA USA.
    Noe, Gregory B.
    US Geol Survey, VA USA.
    Rosenberry, Donald O.
    US Geol Survey, CO USA.
    Trettin, Carl
    US Forest Serv, CA USA.
    Wickland, Kimberly P.
    US Geol Survey, CO USA.
    Allen, Scott T.
    Univ Nevada, NV USA.
    Arias-Ortiz, Ariane
    Univ Calif Berkeley, CA USA.
    Armitage, Anna R.
    Texas A&M Univ Galveston, TX USA.
    Baldocchi, Dennis
    Univ Calif Berkeley, CA USA.
    Banerjee, Kakoli
    Cent Univ Odisha, India.
    Bastviken, David
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Berg, Peter
    Univ Virginia, VA USA.
    Bogard, Matthew J.
    Univ Lethbridge, Canada.
    Chow, Alex T.
    Chinese Univ Hong Kong, Peoples R China.
    Conner, William H.
    Clemson Univ, SC USA.
    Craft, Christopher
    Indiana Univ, IN USA.
    Creamer, Courtney
    US Geol Survey, CA USA.
    Delsontro, Tonya
    Univ Waterloo, Canada.
    Duberstein, Jamie A.
    Clemson Univ, SC USA.
    Eagle, Meagan
    US Geol Survey, MA USA.
    Fennessy, M. Siobhan
    Kenyon Coll, OH USA.
    Finkelstein, Sarah A.
    Univ Toronto, Canada.
    Goeckede, Mathias
    Max Planck Inst Biogeochem, Germany.
    Grunwald, Sabine
    Univ Florida, FL USA.
    Halabisky, Meghan
    Univ Washington, WA USA.
    Herbert, Ellen
    Ducks Unltd, TN USA.
    Jahangir, Mohammad M. R.
    Bangladesh Agr Univ, Bangladesh.
    Johnson, Olivia F.
    US Geol Survey, ND 58401 USA; Kent State Univ, OH USA.
    Jones, Miriam C.
    US Geol Survey, VA USA.
    Kelleway, Jeffrey J.
    Univ Wollongong, Australia; Univ Wollongong, Australia.
    Knox, Sara
    McGill Univ, Canada.
    Kroeger, Kevin D.
    US Geol Survey, MA USA.
    Kuehn, Kevin A.
    Univ Southern Mississippi, MS USA.
    Lobb, David
    Univ Manitoba, Canada.
    Loder, Amanda L.
    Univ Toronto, Canada.
    Ma, Shizhou
    Univ Saskatchewan, Canada.
    Maher, Damien T.
    Southern Cross Univ, Australia.
    McNicol, Gavin
    Univ Illinois, IL USA.
    Meier, Jacob
    US Geol Survey, ND 58401 USA.
    Middleton, Beth A.
    US Geol Survey, LA USA.
    Mills, Christopher
    US Geol Survey, CO USA.
    Mistry, Purbasha
    Univ Saskatchewan, Canada.
    Mitra, Abhijit
    Univ Calcutta, India.
    Mobilian, Courtney
    Indiana Univ, IN USA.
    Nahlik, Amanda M.
    US EPA, OR USA.
    Newman, Sue
    South Florida Water Management Dist, FL USA.
    O'Connell, Jessica L.
    Colorado State Univ, CO USA.
    Oikawa, Patty
    Calif State Univ East Bay, CA USA.
    van der Burg, Max Post
    US Geol Survey, ND 58401 USA.
    Schutte, Charles A.
    Rowan Univ, NJ USA.
    Song, Changchun
    Chinese Acad Sci, Peoples R China.
    Stagg, Camille L.
    US Geol Survey, LA USA.
    Turner, Jessica
    Univ Wisconsin Madison, WI USA.
    Vargas, Rodrigo
    Univ Delaware, DE USA.
    Waldrop, Mark P.
    US Geol Survey, CA USA.
    Wallin, Marcus B.
    Swedish Univ Agr Sci, Sweden.
    Wang, Zhaohui Aleck
    Woods Hole Oceanog Inst, MA USA.
    Ward, Eric J.
    US Geol Survey, LA USA.
    Willard, Debra A.
    US Geol Survey, VA USA.
    Yarwood, Stephanie
    Univ Maryland, MD USA.
    Zhu, Xiaoyan
    Jilin Jianzhu Univ, Peoples R China.
    Practical Guide to Measuring Wetland Carbon Pools and Fluxes2023In: Wetlands (Wilmington, N.C.), ISSN 0277-5212, E-ISSN 1943-6246, Vol. 43, no 8, article id 105Article, review/survey (Refereed)
    Abstract [en]

    Wetlands cover a small portion of the world, but have disproportionate influence on global carbon (C) sequestration, carbon dioxide and methane emissions, and aquatic C fluxes. However, the underlying biogeochemical processes that affect wetland C pools and fluxes are complex and dynamic, making measurements of wetland C challenging. Over decades of research, many observational, experimental, and analytical approaches have been developed to understand and quantify pools and fluxes of wetland C. Sampling approaches range in their representation of wetland C from short to long timeframes and local to landscape spatial scales. This review summarizes common and cutting-edge methodological approaches for quantifying wetland C pools and fluxes. We first define each of the major C pools and fluxes and provide rationale for their importance to wetland C dynamics. For each approach, we clarify what component of wetland C is measured and its spatial and temporal representativeness and constraints. We describe practical considerations for each approach, such as where and when an approach is typically used, who can conduct the measurements (expertise, training requirements), and how approaches are conducted, including considerations on equipment complexity and costs. Finally, we review key covariates and ancillary measurements that enhance the interpretation of findings and facilitate model development. The protocols that we describe to measure soil, water, vegetation, and gases are also relevant for related disciplines such as ecology. Improved quality and consistency of data collection and reporting across studies will help reduce global uncertainties and develop management strategies to use wetlands as nature-based climate solutions.

  • 15.
    Barros, Nathan
    et al.
    University Fed Juiz de Fora.
    J Cole, Jonathan
    Cary Institute for Ecosystem Studies.
    Tranvik, Lars J
    Uppsala University.
    Prairie, Yves T
    University of Quebec.
    Bastviken, David
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Huszar, Vera L M
    University Fed Rio de Janeiro.
    del Giorgio, Paul
    University of Quebec.
    Roland, Fabio
    University Fed Juiz de Fora.
    Carbon emission from hydroelectric reservoirs linked to reservoir age and latitude2011In: Nature Geoscience, ISSN 1752-0894, E-ISSN 1752-0908, Vol. 4, no 9, p. 593-596Article in journal (Refereed)
    Abstract [en]

    Hydroelectric reservoirs cover an area of 3.4 x 10(5) km(2) and comprise about 20% of all reservoirs. In addition, they contain large stores of formerly terrestrial organic carbon. Significant amounts of greenhouse gases are emitted(2), especially in the early years following reservoir creation, but the global extent of these emissions is poorly known. Previous estimates of emissions from all types of reservoir indicate that these human-made systems emit 321 Tg of carbon per year (ref. 4). Here we assess the emissions of carbon dioxide and methane from hydroelectric reservoirs, on the basis of data from 85 globally distributed hydroelectric reservoirs that account for 20% of the global area of these systems. We relate the emissions to reservoir age, location biome, morphometric features and chemical status. We estimate that hydroelectric reservoirs emit about 48 Tg C as CO(2) and 3 Tg C as CH(4), corresponding to 4% of global carbon emissions from inland waters. Our estimates are smaller than previous estimates on the basis of more limited data. Carbon emissions are correlated to reservoir age and latitude, with the highest emission rates from the tropical Amazon region. We conclude that future emissions will be highly dependent on the geographic location of new hydroelectric reservoirs.

  • 16.
    Bastviken, D.
    et al.
    Stockholm University.
    Cole, J. J.
    Institute of Ecosystem Studies, Millbrook.
    Pace, M. L.
    Institute of Ecosystem Studies, Millbrook.
    Van de Bogert, M. C.
    University of Wisconsin.
    Fates of methane from different lake habitats: Connecting whole-lake budgets and CH4 emissions2008In: Journal of Geophysical Research, ISSN 0148-0227, E-ISSN 2156-2202, Vol. 113, no G2Article in journal (Refereed)
    Abstract [en]

    Methane (CH4) represents a major product of organic matter decomposition in lakes. Once produced in the sediments, CH4 can be either oxidized or emitted as a greenhouse gas to the atmosphere. Lakes represent an important source of atmospheric CH4, but the relative magnitudes of the internal pathways that lead to CH4 emissions are not yet clear. We quantified internal cycling and methane emissions in three lakes during summer stratification. These methane budgets included: sediment release of CH4 at different depths; water column transport patterns and methane oxidation; methane storage in the water column; and methane emissions to the atmosphere by diffusion and ebullition. The contribution of CH4 carbon, via oxidation by methanotrophic bacteria, to pelagic food webs was also estimated. Despite the very low concentration of CH4 in surface waters, shallow, epilimnetic sediments were major contributors of CH4 to the atmosphere. While 51 - 80% of the CH4 produced in deep sediments was oxidized in the water column, most of the CH4 released from shallow sediment escaped oxidation and reached the atmosphere. Epilimnetic sediments accounted for 100% of CH4 emitted during summer stratification, and 14 - 76% considering the release of CH4 stored in deep water layers during lake circulation after the stratification period; diffusive emission accounted for 26 - 48% and ebullition the remainder. These results indicate that it is important to address transport rates of CH4 from the shallow sediment along with the production-consumption processes when trying to understand methane dynamics and the regulation of lake methane emissions.

  • 17.
    Bastviken, David
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Anoxic degradation of organic matter in lakes: implications for carbon cycling and aquatic food webs2002Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Considerable evidence from laboratory studies and marine environments suggests that degradation of organic matter (OM) is restricted under anoxic conditions compared to when molecular oxygen (O2) is present. However, other studies contradict this view since they found similar OM degradation rates and bacterial growth rates under both oxic and anoxic conditions in aquatic environments. Studies from freshwater environments are rare, and have been primarily based on bacterial production estimates. Anoxic degradation of OM in lakes is commonly considered to be slow and of little importance for overall lake food webs compared to oxic degradation. The present thesis and the work it is based on challenge this view. First, the performance of a commonly used method to measure bacterial production was tested in both oxic and anoxic lake water. Then, the oxic and anoxic potentials of bacterial growth and OM mineralization were compared in lake water and sediment. In addition, I assessed the potential of carbon transfer from methane (CH4; i.e. an end-product of anoxic degradation) to pelagic food webs. Three methods for measuring water column methane oxidation were evaluated. Then, the potential transport of methane carbon into the microbial community via methane oxidation, and further -up the food web- into the zooplankton community was estimated. Results indicate 1) that OM degradation and bacterial growth may be similar in oxic and anoxic lake environments, 2) that OM characteristics may be more important for the mineralization than the O2 regime per se in the short term (daysweeks), and 3) that methane can be a significant source of carbon and energy for pelagic food webs. This suggests that the anoxic carbon metabolism may be extensive and potentially important for pelagic organisms in many lakes.

    List of papers
    1. The leucine incorporation method estimates bacterial growth equally well in both oxic and anoxic lake waters
    Open this publication in new window or tab >>The leucine incorporation method estimates bacterial growth equally well in both oxic and anoxic lake waters
    2001 (English)In: Applied and Environmental Microbiology, ISSN 0099-2240, E-ISSN 1098-5336, Vol. 67, no 7, p. 2916-2921Article in journal (Refereed) Published
    Abstract [en]

    Bacterial biomass production is often estimated from incorporation of radioactively labeled leucine into protein, in both oxic and anoxic waters and sediments. However, the validity of the method in anoxic environments has so far not been tested. We compared the leucine incorporation of bacterial assemblages growing in oxic and anoxic waters from three lakes differing in nutrient and humic contents, The method was modified to avoid O-2 contamination by performing the incubation in syringes. Isotope saturation levels in oxic and anoxic waters were determined, and leucine incorporation rates were compared to microscopically observed bacterial growth. Finally, we evaluated the effects of O-2 contamination during incubation with leucine, as well as the potential effects of a headspace in the incubation vessel, isotope saturation occurred at a leucine concentration of above about 50 nM in both ode and anoxic waters from all three lakes. Leucine incorporation rates were linearly correlated to observed growth, and there was no significant difference between oxic and anoxic conditions. O-2 contamination of anoxic water during I-h incubations with leucine had no detectable impact on the incorporation rate, while a headspace in the incubation vessel caused leucine incorporation to increase in both anoxic and O-2-contaminated samples. The results indicate that the leucine incorporation method relates equally to bacterial growth rates under oxic and anoxic conditions and that incubation should be performed without a headspace.

    National Category
    Social Sciences
    Identifiers
    urn:nbn:se:liu:diva-49209 (URN)10.1128/​AEM.67.7.2916-2921.2001 (DOI)
    Available from: 2009-10-11 Created: 2009-10-11 Last updated: 2018-10-05Bibliographically approved
    2. Similar bacterial growth on dissolved organic matter in anoxic and oxic lake water
    Open this publication in new window or tab >>Similar bacterial growth on dissolved organic matter in anoxic and oxic lake water
    2001 (English)In: Aquatic Microbial Ecology, ISSN 0948-3055, E-ISSN 1616-1564, Vol. 24, no 1, p. 41-49Article in journal (Refereed) Published
    Abstract [en]

    Anoxic metabolism yields less energy per unit substrate utilized than oxic respiration. In addition, substrate availability is believed to be reduced under anoxic conditions since oxygenases cannot be used. Consequently, it is generally assumed that bacteria grow slower in anoxic environments than in oxic environments. The results of the present study challenge this view. We compared the growth of bacterial assemblages under carbon-limited conditions in lake water under anoxic and oxic conditions. Bioassay experiments were performed with water from 3 lakes differin9 in nutrient concentrations and organic matter content. Amon9 bacteria usin9 the same source of organic matter, median anoxic growth rates were 84 to 110% of oxic growth rates. The total biomass yield durin9 the experiments did not differ between anoxic and oxic treatments. We suggest that anoxic bacterial growth was regulated by substrate availability rather than by metabolic energy yield and that availability of organic matter under anoxic conditions was equal to or even greater than that in oxic treatments. This implies that anoxic decomposition rates may actually have been faster than oxic rates.

    Keywords
    DOC, DOM, Anaerobic degradation, Bacteria
    National Category
    Social Sciences Interdisciplinary
    Identifiers
    urn:nbn:se:liu:diva-31046 (URN)10.3354/ame024041 (DOI)16755 (Local ID)16755 (Archive number)16755 (OAI)
    Available from: 2009-10-09 Created: 2009-10-09 Last updated: 2018-10-05Bibliographically approved
    3. Simultaneous measurements of organic carbon mineralization and bacterial production in oxic and anoxic lake sediments
    Open this publication in new window or tab >>Simultaneous measurements of organic carbon mineralization and bacterial production in oxic and anoxic lake sediments
    2003 (English)In: Microbial Ecology, ISSN 0095-3628, E-ISSN 1432-184X, Vol. 46, no 1, p. 73-82Article in journal (Refereed) Published
    Abstract [en]

    Based on work in marine sediments it can be hypothesized that (i) overall OM mineralization depends on the enzymatic capacity and is largely independent from the energy yield, (ii) similar oxic and anoxic rates are expected for fresh OM, while oxic rates should be faster for old OM that is partially degraded or adsorbed to particles, and (iii) that the thermodynamic energy yield does not regulate mineralization, but primarily determines the energy fraction allocated to bacterial production (BP). We addressed these hypotheses by simultaneous measurements of mineralization rates (MR) and BP in sediments from a eutrophic lake, along with MR measurements in sediments of a dystrophic lake. Anoxic MR were 44 and 78% of oxic MR in the eutrophic and dystrophic lake, respectively, which was always higher than expected given the theoretical energy yields. The BP:MR ratio was 0.94 and 0.24 in the oxic and anoxic treatments, respectively, in accordance with the expected energy yields. Thus, the results support all three hypotheses above. We also critically discuss BP measurements in sediments and suggest that bacterial growth efficiency values from simultaneous MR and BP measurements can be used to evaluate the reliability of BP estimates.

    National Category
    Social Sciences Interdisciplinary
    Identifiers
    urn:nbn:se:liu:diva-30668 (URN)10.1007/s00248-002-1061-9 (DOI)16268 (Local ID)16268 (Archive number)16268 (OAI)
    Available from: 2009-10-09 Created: 2009-10-09 Last updated: 2018-10-05Bibliographically approved
    4. Measurement of methane oxidation in lakes: A comparison of methods
    Open this publication in new window or tab >>Measurement of methane oxidation in lakes: A comparison of methods
    2002 (English)In: Environmental Science & Technology, ISSN 0013-936X, Vol. 36, no 15, p. 3354-3361Article in journal (Refereed) Published
    Abstract [en]

    Methane oxidation in lakes constrains the methane emissions to the atmosphere and simultaneously enables the transfer of methane carbon to pelagic food webs, Several different methods have been used to estimate methane oxidation, but these methods have not previously been compared. In this study, we present methane oxidation estimates from three different lakes during summer and winter, using methods based on the transformation of added (CH4)-C-14, the fractionation of natural methane C-13, and the mass balance modeling of concentration gradients, All methods yielded similar results, including similar differences between lakes and seasons. Average methane oxidation rates varied from 0.25 to 81 mg of C m(-2) d(-1) and indicate that the three methods are comparable, although they to some extent take different processes into account. Critical issues as well as drawbacks and advantages with the used methods are thoroughly discussed. We conclude that methods using the stable isotope or mass balance modeling approach represent promising alternatives, particularly for studies focusing on ecosystem-scale carbon metabolism.

    Place, publisher, year, edition, pages
    American Chemical Society (ACS), 2002
    National Category
    Physical Geography
    Identifiers
    urn:nbn:se:liu:diva-28226 (URN)10.1021/es010311p (DOI)000177242600043 ()2-s2.0-0036667658 (Scopus ID)
    Available from: 2009-10-09 Created: 2009-10-09 Last updated: 2018-10-05Bibliographically approved
    5. Methane as a source of carbon and energy for lake pelagic food webs
    Open this publication in new window or tab >>Methane as a source of carbon and energy for lake pelagic food webs
    2003 (English)In: Ecology, ISSN 0012-9658, E-ISSN 1939-9170, Vol. 84, no 4, p. 969-981Article in journal (Refereed) Published
    Abstract [en]

    Water-column methane oxidation can represent a substantial carbon transformation pathway in lakes, and circumstantial evidence indicates that methane may be a potentially important source of carbon for pelagic food webs. We estimated methanotrophic bacterial production (MBP), methanotrophic bacterial growth efficiency (MBGE), heterotrophic bacterial production (HBP), primary production (PP), and the relative contribution of methanotrophic bacteria to overall bacterial biomass in three very different lakes during summer and winter. In addition, we measured stable carbon isotope ratios in particulate organic matter (POM), surface sediments, zooplankton, and methane. MBP corresponded to 0.3-7% of the organic C production by primary producers, and 0.5-17% of HBP during summer. During winter, MBP was 3-120% of HBP. MBP generally dominated the heterotrophic bacterial production at greater depths. Methanotrophic biomass was 3-11% of total bacterial biomass on a depth-integrated basis. Zooplankton were generally more depleted in 13C than POM. If phytoplankton d13C signatures were -35 to -30ë, such as the POM signals, observed zooplankton signatures could be explained by a fraction of 5-15% methanotrophic bacteria in their diet. The results indicate that methanotrophic bacteria can provide a significant food source for zooplankton, and that methane oxidation represents a potentially important benthic-pelagic carbon and energy link in many lakes, particularly during winter.

    Keywords
    aquatic food webs, bacterial growth efficiency, carbon cycling, methane, as source of C and energy in lake food webs, methane oxidation, methanotrophic bacteria, stable isotopes, Swedish lakes, zooplankton
    National Category
    Social Sciences Interdisciplinary
    Identifiers
    urn:nbn:se:liu:diva-30671 (URN)10.1890/0012-9658(2003)084[0969:MAASOC]2.0.CO;2 (DOI)16272 (Local ID)16272 (Archive number)16272 (OAI)
    Available from: 2009-10-09 Created: 2009-10-09 Last updated: 2018-10-05Bibliographically approved
  • 18.
    Bastviken, David
    Stockholm University, Sweden.
    Methane2009In: Encyclopedia of Inland Waters, Oxford: Elsevier , 2009, 1, p. 783-805Chapter in book (Refereed)
    Abstract [en]

    Inland aquatic habitats occur world-wide at all scales from marshes, swamps and temporary puddles, to ponds, lakes and inland seas; from streams and creeks to rolling rivers. Vital for biological diversity, ecosystem function and as resources for human life, commerce and leisure, inland waters are a vital component of life on Earth. The Encyclopedia of Inland Waters describes and explains all the basic features of the subject, from water chemistry and physics, to the biology of aquatic creatures and the complex function and balance of aquatic ecosystems of varying size and complexity. Used and abused as an essential resource, it is vital that we understand and manage them as much as we appreciate and enjoy them. This extraordinary reference brings together the very best research to provide the basic and advanced information necessary for scientists to understand these ecosystems - and for water resource managers and consultants to manage and protect them for future generations. . Encyclopedic reference to Limnology - a key core subject in ecology taught as a specialist course in universities . Over 240 topic related articles cover the field . Gene Likens is a renowned limnologist and conservationist, Emeritus Director of the Institute of Ecosystems Research, elected member of the American Philosophical Society and recipient of the 2001 National Medal of Science . Subject Section Editors and authors include the very best research workers in the field

  • 19.
    Bastviken, David
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Reference database for literature survey of methods currently used for measuring greenhouse gas fluxes. Se paper providing the link to this site for details2021Data set
    Download full text (xlsx)
    GHG flux methods reference database
  • 20.
    Bastviken, David
    et al.
    Linköping University, Department of Thematic Studies, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Cole, Jonathan
    Institute of Ecosystem Studies, Millbrook, New York, USA.
    Pace, Michael
    Institute of Ecosystem Studies, Millbrook, New York, USA.
    Tranvik, Lars
    Department of Limnology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden.
    Methane emissions from lakes: Dependence of lake characteristics, two regional assessments, and a global estimate2004In: Global Biogeochemical Cycles, ISSN 0886-6236, E-ISSN 1944-9224, Vol. 18, no 4, article id GB4009Article in journal (Refereed)
    Abstract [en]

    [ 1] Lake sediments are "hot spots'' of methane production in the landscape. However, regional and global lake methane emissions, contributing to the greenhouse effect, are poorly known. We developed predictions of methane emissions from easily measured lake characteristics based on measurements for 11 North American and 13 Swedish lakes, and literature values from 49 lakes. Results suggest that open water methane emission can be predicted from variables such as lake area, water depth, concentrations of total phosphorus, dissolved organic carbon, and methane, and the anoxic lake volume fraction. Using these relations, we provide regional estimates from lakes in Sweden and the upper midwest of the United States. Considering both open water and plant-mediated fluxes, we estimate global emissions as 8 - 48 Tg CH4 yr(-1) (6 - 16% of total natural methane emissions and greater than oceanic emission), indicating that lakes should be included as a significant source in global methane budgets.

  • 21.
    Bastviken, David
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Ejlertsson, Jörgen
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Sundh, Ingvar
    Department of Microbiology, Swedish University of Agricultural Sciences.
    Tranvik, Lars
    Department of Limnology, Uppsala University.
    Methane as a source of carbon and energy for lake pelagic food webs2003In: Ecology, ISSN 0012-9658, E-ISSN 1939-9170, Vol. 84, no 4, p. 969-981Article in journal (Refereed)
    Abstract [en]

    Water-column methane oxidation can represent a substantial carbon transformation pathway in lakes, and circumstantial evidence indicates that methane may be a potentially important source of carbon for pelagic food webs. We estimated methanotrophic bacterial production (MBP), methanotrophic bacterial growth efficiency (MBGE), heterotrophic bacterial production (HBP), primary production (PP), and the relative contribution of methanotrophic bacteria to overall bacterial biomass in three very different lakes during summer and winter. In addition, we measured stable carbon isotope ratios in particulate organic matter (POM), surface sediments, zooplankton, and methane. MBP corresponded to 0.3-7% of the organic C production by primary producers, and 0.5-17% of HBP during summer. During winter, MBP was 3-120% of HBP. MBP generally dominated the heterotrophic bacterial production at greater depths. Methanotrophic biomass was 3-11% of total bacterial biomass on a depth-integrated basis. Zooplankton were generally more depleted in 13C than POM. If phytoplankton d13C signatures were -35 to -30ë, such as the POM signals, observed zooplankton signatures could be explained by a fraction of 5-15% methanotrophic bacteria in their diet. The results indicate that methanotrophic bacteria can provide a significant food source for zooplankton, and that methane oxidation represents a potentially important benthic-pelagic carbon and energy link in many lakes, particularly during winter.

  • 22.
    Bastviken, David
    et al.
    Linköping University, Department of Thematic Studies, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Ejlertsson, Jörgen
    Linköping University, Department of Thematic Studies, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Tranvik, Lars
    Department of Limnology, Uppsala University, Uppsala, Sweden.
    Measurement of methane oxidation in lakes: A comparison of methods2002In: Environmental Science & Technology, ISSN 0013-936X, Vol. 36, no 15, p. 3354-3361Article in journal (Refereed)
    Abstract [en]

    Methane oxidation in lakes constrains the methane emissions to the atmosphere and simultaneously enables the transfer of methane carbon to pelagic food webs, Several different methods have been used to estimate methane oxidation, but these methods have not previously been compared. In this study, we present methane oxidation estimates from three different lakes during summer and winter, using methods based on the transformation of added (CH4)-C-14, the fractionation of natural methane C-13, and the mass balance modeling of concentration gradients, All methods yielded similar results, including similar differences between lakes and seasons. Average methane oxidation rates varied from 0.25 to 81 mg of C m(-2) d(-1) and indicate that the three methods are comparable, although they to some extent take different processes into account. Critical issues as well as drawbacks and advantages with the used methods are thoroughly discussed. We conclude that methods using the stable isotope or mass balance modeling approach represent promising alternatives, particularly for studies focusing on ecosystem-scale carbon metabolism.

  • 23.
    Bastviken, David
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Ejlertsson, Jörgen
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Tranvik, Lars
    2Department of Limnology, Uppsala University, Sweden.
    Similar bacterial growth on dissolved organic matter in anoxic and oxic lake water2001In: Aquatic Microbial Ecology, ISSN 0948-3055, E-ISSN 1616-1564, Vol. 24, no 1, p. 41-49Article in journal (Refereed)
    Abstract [en]

    Anoxic metabolism yields less energy per unit substrate utilized than oxic respiration. In addition, substrate availability is believed to be reduced under anoxic conditions since oxygenases cannot be used. Consequently, it is generally assumed that bacteria grow slower in anoxic environments than in oxic environments. The results of the present study challenge this view. We compared the growth of bacterial assemblages under carbon-limited conditions in lake water under anoxic and oxic conditions. Bioassay experiments were performed with water from 3 lakes differin9 in nutrient concentrations and organic matter content. Amon9 bacteria usin9 the same source of organic matter, median anoxic growth rates were 84 to 110% of oxic growth rates. The total biomass yield durin9 the experiments did not differ between anoxic and oxic treatments. We suggest that anoxic bacterial growth was regulated by substrate availability rather than by metabolic energy yield and that availability of organic matter under anoxic conditions was equal to or even greater than that in oxic treatments. This implies that anoxic decomposition rates may actually have been faster than oxic rates.

  • 24.
    Bastviken, David
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Lucia Santoro, Ana
    Univ Fed Rio de Janeiro.
    Marotta, Humberto
    Univ Fed Rio de Janeiro.
    Queiroz Pinho, Luana
    Univ Fed Rio de Janeiro.
    Fernandes Calheiros, Debora
    Ctr Agr Res Pantanal Embrapa Pantanal.
    Crill, Patrick
    Stockholm University.
    Enrich-Prast, Alex
    Univ Fed Rio de Janeiro.
    Methane Emissions from Pantanal, South America, during the Low Water Season: Toward More Comprehensive Sampling2010In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 44, no 14, p. 5450-5455Article in journal (Refereed)
    Abstract [en]

    Freshwater environments contribute 75% of the natural global methane (CH4) emissions. While there are indications that tropical lakes and reservoirs emit 58-400% more CH4 per unit area than similar environments in boreal and temperate biomes, direct measurements of tropical lake emissions are scarce. We measured CH4 emissions from 16 natural shallow lakes in the Pantanal region of South America, one of the worlds largest tropical wetland areas, during the low water period using floating flux chambers. Measured fluxes ranged from 3.9 to 74.2 mmol m(-2) d(-1) with the average from all studied lakes being 8.8 mmol m(-2) d(-1) (131.8 mg CH4 m(-2) d(-1)), of which ebullition accounted for 91% of the flux (28-98% on individual lakes). Diel cycling of emission rates was observed and therefore 24-h long measurements are recommended rather than short-term measurements not accounting for the full diel cycle. Methane emission variability within a lake may be equal to or more important than between lake variability in floodplain areas as this study identified diverse habitats within lakes having widely different flux rates. Future measurements with static floating chambers should be based on many individual chambers distributed in the various subenvironments of a lake that may differ in emissions in order to account for the within lake variability.

  • 25.
    Bastviken, David
    et al.
    Linköping University, The Tema Institute, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Natchimuthu, Sivakiruthika
    Linköping University, The Tema Institute, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Panneer Selvam, Balathandayuthabani
    Lund University, Sweden.
    Letter: Response: Inland water greenhouse gas emissions: when to model and when to measure? in GLOBAL CHANGE BIOLOGY, vol 21, issue 4, pp 1379-13802015In: Global Change Biology, ISSN 1354-1013, E-ISSN 1365-2486, Vol. 21, no 4, p. 1379-1380Article in journal (Other academic)
    Abstract [en]

    n/a

  • 26.
    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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  • 27.
    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
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    Facilitating the use of low-cost methane (CH4) sensors in flux chambers: calibration, data processing, and describing an open source make-it-yourself logger
  • 28.
    Bastviken, David
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Olsson, M
    Linköping University, Department of Physics, Chemistry and Biology, Biology.
    Tranvik, L
    Department of Limnology, Uppsala University.
    Simultaneous measurements of organic carbon mineralization and bacterial production in oxic and anoxic lake sediments2003In: Microbial Ecology, ISSN 0095-3628, E-ISSN 1432-184X, Vol. 46, no 1, p. 73-82Article in journal (Refereed)
    Abstract [en]

    Based on work in marine sediments it can be hypothesized that (i) overall OM mineralization depends on the enzymatic capacity and is largely independent from the energy yield, (ii) similar oxic and anoxic rates are expected for fresh OM, while oxic rates should be faster for old OM that is partially degraded or adsorbed to particles, and (iii) that the thermodynamic energy yield does not regulate mineralization, but primarily determines the energy fraction allocated to bacterial production (BP). We addressed these hypotheses by simultaneous measurements of mineralization rates (MR) and BP in sediments from a eutrophic lake, along with MR measurements in sediments of a dystrophic lake. Anoxic MR were 44 and 78% of oxic MR in the eutrophic and dystrophic lake, respectively, which was always higher than expected given the theoretical energy yields. The BP:MR ratio was 0.94 and 0.24 in the oxic and anoxic treatments, respectively, in accordance with the expected energy yields. Thus, the results support all three hypotheses above. We also critically discuss BP measurements in sediments and suggest that bacterial growth efficiency values from simultaneous MR and BP measurements can be used to evaluate the reliability of BP estimates.

  • 29.
    Bastviken, David
    et al.
    Linköping University, Department of Thematic Studies, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Persson, Linn
    Institute of Applied Environmental Research, Stockholm University, Sweden.
    Odham, Göran
    Institute of Applied Environmental Research, Stockholm University, Sweden.
    Tranvik, Lars
    Department of Limnology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden.
    Degradation of dissolved organic matter in oxic and anoxic lake water2004In: Limnology and Oceanography, ISSN 0024-3590, E-ISSN 1939-5590, Vol. 49, no 1, p. 109-116Article in journal (Refereed)
    Abstract [en]

    Decades of conflicting results have fueled a debate about how O-2 affects organic matter (OM) degradation and carbon cycling. In a laboratory study, using both OM taken directly from a humic lake and chemically isolated fulvic acid, we monitored the mineralization of dissolved OM in freshwater under purely oxic and anoxic conditions, under oxic then anoxic conditions, and under anoxic then oxic conditions, for 426 d. Between 5% and 24% of the initial OM was mineralized, with most extensive mineralization occurring under purely oxic and anoxic-oxic conditions. A sequential change in the O-2 regime did not result in greater overall degradation, but initially anoxic conditions favored subsequent oxic mineralization. A substantially greater fraction of the OM was degraded than in previous shorter studies, with as much as 50% of the total OM degradation occurring after 147 d into the experiment. Three fractions of the degradable OM were identified: OM degraded only under oxic conditions (68-78%), OM degraded more rapidly under anoxic conditions than under oxic conditions (16-18%), and OM degraded at equal rates under both oxic and anoxic conditions (6-14%). The degradation patterns of natural dissolved OM from a humic lake and chemically isolated fulvic acid were very similar, which indicates a similar level of bioavailability. The difference between anoxic and oxic degradation was greater in our long-term studies than in previous short-term experiments, which indicates that the oxic and anoxic degradation potentials vary with increasing overall OM recalcitrance and that similar oxic and anoxic degradation rates can be expected in short-term experiments in which <30% of the long-term degradable OM is allowed to decompose.

  • 30.
    Bastviken, David
    et al.
    Linköping University, Department of Social and Welfare Studies, Learning, Aesthetics, Natural science. Linköping University, Faculty of Educational Sciences.
    Samuelsson, C.
    Ståhlberg, Carina
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Similar organic matter mineralisation rates under oxic, methanogenic, and sulphate reducing conditions in late winter sediment of a Swedish river2006Article in journal (Refereed)
  • 31.
    Bastviken, David
    et al.
    Stockholm University.
    Sandén, Per
    Linköping University, The Tema Institute, Centre for Climate Science and Policy Research . Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Svensson, Teresia
    Linköping University, The Tema Institute, Centre for Climate Science and Policy Research . Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Ståhlberg, Carina
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Magounakis, Malin
    Linköping University, The Tema Institute, Centre for Climate Science and Policy Research . Linköping University, Faculty of Arts and Sciences.
    Öberg, Gunilla
    Linköping University, The Tema Institute, Centre for Climate Science and Policy Research . Linköping University, Faculty of Arts and Sciences.
    Chloride retention and release in a boreal forest soil: effects of soil water residence time and nitrogen and chloride loads2006In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 40, no 9, p. 2977-2982Article in journal (Refereed)
    Abstract [en]

    The common assumption that chloride (Cl-) is conservative in soils and can be used as a groundwater tracer is currently being questioned, and an increasing number of studies indicate that Cl- can be retained in soils. We performed lysimeter experiments with soil from a coniferous forest in southeast Sweden to determine whether pore water residence time and nitrogen and Cl- loads affected Cl- retention. Over the first 42 days there was a net retention of Cl- with retention rates averaging 3.1 mg Cl- m-2 d-1 (68% of the added Cl- retained over 42 days). Thereafter, a net release of Cl- at similar rates was observed for the remaining experimental period (85 d). Longer soil water residence time and higher Cl- load gave higher initial retention and subsequent release rates than shorter residence time and lower Cl- load did. Nitrogen load did not affect Cl transformation rates. This study indicates that simultaneous retention and release of Cl- can occur in soils, and that rates may be considerable relative to the load. The retention of Cl- observed was probably due to chlorination of soil organic matter or ion exchange. The cause of the shift between net retention and net release is unclear, but we hypothesize that the presence of O2 or the presence of microbially available organic matter regulates Cl- retention and release rates.

  • 32.
    Bastviken, David
    et al.
    Linköping University, The Tema Institute, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Sundgren, Ingrid
    Linköping University, The Tema Institute, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Natchimuthu, Sivakiruthika
    Linköping University, The Tema Institute, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Reyier, Henrik
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Gålfalk, Magnus
    Linköping University, The Tema Institute, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Technical Note: Cost-efficient approaches to measure carbon dioxide (CO2) fluxes and concentrations in terrestrial and aquatic environments using mini loggers2015In: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 12, no 12, p. 3849-3859Article in journal (Refereed)
    Abstract [en]

    Fluxes of CO2 are important for our understanding of the global carbon cycle and greenhouse gas balances. Several significant CO2 fluxes in nature may still be unknown as illustrated by recent findings of high CO2 emissions from aquatic environments, previously not recognized in global carbon balances. Therefore, it is important to develop convenient and affordable ways to measure CO2 in many types of environments. At present, direct measurements of CO2 fluxes from soil or water, or CO2 concentrations in surface water, are typically labor intensive or require costly equipment. We here present an approach with measurement units based on small inexpensive CO2 loggers, originally made for indoor air quality monitoring, that were tested and adapted for field use. Measurements of soil-atmosphere and lake-atmosphere fluxes, as well as of spatiotemporal dynamics of water CO2 concentrations (expressed as the equivalent partial pressure, pCO(2aq)) in lakes and a stream network are provided as examples. Results from all these examples indicate that this approach can provide a cost- and labor-efficient alternative for direct measurements and monitoring of CO2 flux and pCO(2aq) in terrestrial and aquatic environments.

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  • 33.
    Bastviken, David
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Svensson, Teresia
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Karlsson, Susanne
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Sandén, Per
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Öberg, Gunilla
    IRES, UBC, Canada.
    Temperature sensitivity indicates enzyme controlled chlorination of soil organic matter2009In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 43, no 10, p. 3569-3573Article in journal (Refereed)
    Abstract [en]

    Old assumptions that chloride is inert and that most chlorinated organic matter in soils is anthropogenic have been challenged by findings of naturally formed organochlorines. Such natural chlorination has been recognized for several decades, but there are still very few measurements of chlorination rates or estimates of the quantitative importance of terrestrial chlorine transformations. While much is known about the formation of specific compounds, bulk chlorination remains poorly understood in terms of mechanisms and effects of environmental factors. We quantified bulk chlorination rates in coniferous forest soil using 36Cl-chloride in tracer experiments at different temperatures and with and without molecular oxygen (O2). Chlorination was enhanced by the presence of O2 and had a temperature optimum at 20 °C. Minimum rates were found at high temperatures (50 °C) or under anoxic conditions. The results indicate (1) that most of the chlorination between 4 and 40 °C was biotic and driven by O2 dependent enzymes, and (2) that there is also slower background chlorination occurring under anoxic conditions at 20 °C and under oxic conditions at 50 °C. Hence, while oxic and biotic chlorination clearly dominated, chlorination by other processes including possible abiotic reactions was also detected.

  • 34.
    Bastviken, David
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Svensson, Teresia
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Sandén, Per
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Kylin, Henrik
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Chlorine cycling and fates of 36Cl in terrestrial environments2013Report (Other academic)
    Abstract [en]

    Chlorine-36 (36Cl), a radioisotope of chlorine (Cl) with a half-life of 301,000 years, is present in some types of nuclear waste and is disposed in repositories for radioactive waste. As the release of 36Cl from such repositories to the near surface environment has to be taken into account it is of interest to predict possible fates of 36Cl under various conditions as a part of the safety assessments of repositories for radioactive waste. This report aims to summarize the state of the art knowledge on Cl cycling in terrestrial environments. The view on Cl cycling in terrestrial environments is changing due to recent research and it is clear that the chloride ion (Cl) is more reactive than previously believed. We group the major findings in three categories below according to the amount of data in support of the findings.

    From the result presented in this report it is evident that:

    • There is an ubiquitous and extensive natural chlorination of organic matter in terrestrial ecosystems.
    • The abundance of naturally formed chlorinated organic compounds (Clorg) frequently exceeds the abundance of Cl, particularly in soils. Thereby Clorg in many cases dominates the total Cl pool.
    • This has important implications for Cl transport. When reaching surface soils Cl will not be a suitable tracer of water and will instead enter other Cl pools (Clorg and biomass) that prolong residence times in the system.
    • Cl dominates import and export from terrestrial ecosystems while Clorg and biomass Cl can dominate the standing stock Cl within terrestrial ecosystems.
    • Both Cl and Clorg pools have to be considered separately in future monitoring programs addressing Cl cycling.

    Further, there are also indications (in need of confirmation by additional studies) that:

    • There is a rapid and large uptake of Cl by organisms and an accumulation in green plant parts. A surprisingly large proportion of total catchment Cl (up to 60%) can be found in the terrestrial biomass.
    • Emissions of total volatile organohalogens could be a significant export pathway of Cl from the systems.
    • Some of the Clorg may be very persistent and resist degradation better than average organic matter. This may lead to selective preservation of some Clorg (with associated low bioavailability).
    • There is a production of Clorg in tissues of e.g. plants and animals and Cl can accumulate as
    • chlorinated fatty acids in organisms.

    Most other nevertheless important aspects are largely unknown due to lack of data. Key unknowns include:

    • The development over time of major Cl pools and fluxes. As long as such data is lacking we cannot assess net changes over time.
    • How the precesses behind chlorination, dechlorination and transport patterns in terrestrial systems are regulated and affected by environmental factors.
    • The ecological roles of the chlorine cycling in general.
    • The ecological role of the microbial chlorination in particular.
    • The chlorine cycling in aquatic environments – including Cl and Clorg pools in sediment and water, are largely missing.

    Given the limited present information available, and particularly the lack of data with a temporal dimension and the lack of process understanding, predictive models are challenging. We also summarize currently available methods to study Cl in the environment.

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    Chlorine cycling and fates of 36Cl in terrestrial environments
  • 35.
    Bastviken, David T. E.
    et al.
    Uppsala University, Uppsala, Sweden.
    Caraco, Nina F.
    Institute of Ecosystem Studies, Millbrook, USA.
    Cole, Jonathan J.
    Institute of Ecosystem Studies, Millbrook, USA.
    Experimental measurements of zebra mussel (Dreissena polymorpha) impacts on phytoplankton community composition1998In: Freshwater Biology, ISSN 0046-5070, E-ISSN 1365-2427, Vol. 39, no 2, p. 375-386Article in journal (Refereed)
    Abstract [en]

    1. To investigate direct effects of zebra mussel (Dreissena polymorpha) feeding activities on phytoplankton community composition, short-term microcosm experiments were performed in natural water with complex phytoplankton communities. Both gross effects (without resuspension of mussel excretions) and net effects (with resuspension) were studied. 2. Gross clearance rates were not selective; essentially all taxa were removed at similar rates ranging from 24 to 63 mt mussel(-1) h(-1). Net clearance rates were highly selective; different plankton taxa were removed at very different rates, ranging from 12 to 83% of the gross rates, leading to consistent changes in the phytoplankton community composition. Thus, although zebra mussels can cause most phytoplankton to decline, there is considerable variation among taxa in either pre-digestive selection or post-digestive survival. 3. The direct, short-term effects of zebra mussels on phytoplankton community composition are consistent with some of the major changes observed in the Hudson River since establishment of zebra mussels. 4. We show, with simple calculations, how zebra mussel filtration rate, its selective efficiency on various taxa, and phytoplankton growth rates interact to produce changes in the phytoplankton composition.

  • 36.
    Bastviken, David
    et al.
    Department of geology and geochemistry Stockholm University.
    Thomsen, Frida
    The Tema institute Linköpings universitet.
    Svensson, Teresia
    Linköping University, Faculty of Arts and Sciences. Linköping University, The Tema Institute.
    Karlsson, Susanne
    Linköping University, Faculty of Arts and Sciences. Linköping University, The Tema Institute.
    Sandén, Per
    Linköping University, Faculty of Arts and Sciences. Linköping University, The Tema Institute.
    Shaw, George
    Division of agricultural and environmental sciences University of Nottingham.
    Matucha, Miroslav
    Institute of experimental botany Ac. Sci. Czech Rep.
    Öberg, Gunilla
    Institute for resources, environment and sustainability University of British Colombia.
    Chloride retention in forest soil by microbial uptake and by natural chlorination of organic matter2007In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 71, no 13, p. 3182-3192Article in journal (Refereed)
    Abstract [en]

    Inorganic chlorine (i.e. chloride, Clin) is generally considered inert in soil and is often used as a tracer of soil and ground water movements. However, recent studies indicate that substantial retention or release of Clin can occur in soil, but the rates and processes responsible under different environmental conditions are largely unknown. We performed 36Cl tracer experiments which indicated that short-term microbial uptake and release of Clin, in combination with more long-term natural formation of chlorinated organic matter (Clorg), caused Clin imbalances in coniferous forest soil. Extensive microbial uptake and release of Clin occurred over short time scales, and were probably associated with changes in environmental conditions. Up to 24% of the initially available Clin within pore water was retained by microbial uptake within a week in our experiments, but most of this Clin was released to the pore water again within a month, probably associated with decreasing microbial populations. The natural formation of Clorg resulted in a net immobilization of 4% of the initial pore water Clin over four months. If this rate is representative for the area where soil was collected, Clorg formation would correspond to a conversion of 25% of the yearly wet deposition of Clin. The study illustrates the potential of two Clin retaining processes in addition to those previously addressed elsewhere (e.g. uptake of chloride by vegetation). Hence, several processes operating at different time scales and with different regulation mechanisms can cause Clin imbalances in soil. Altogether, the results of the present study (1) provide evidence that Clin cannot be assumed to be inert in soil, (2) show that microbial exchange can regulate pore water Clin concentrations and (3) confirm the controversial idea of substantial natural chlorination of soil organic matter. © 2007 Elsevier Ltd. All rights reserved.

  • 37.
    Bastviken, David
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Tranvik, Lars
    Department of Limnology, Uppsala University, Sweden.
    The leucine incorporation method estimates bacterial growth equally well in both oxic and anoxic lake waters2001In: Applied and Environmental Microbiology, ISSN 0099-2240, E-ISSN 1098-5336, Vol. 67, no 7, p. 2916-2921Article in journal (Refereed)
    Abstract [en]

    Bacterial biomass production is often estimated from incorporation of radioactively labeled leucine into protein, in both oxic and anoxic waters and sediments. However, the validity of the method in anoxic environments has so far not been tested. We compared the leucine incorporation of bacterial assemblages growing in oxic and anoxic waters from three lakes differing in nutrient and humic contents, The method was modified to avoid O-2 contamination by performing the incubation in syringes. Isotope saturation levels in oxic and anoxic waters were determined, and leucine incorporation rates were compared to microscopically observed bacterial growth. Finally, we evaluated the effects of O-2 contamination during incubation with leucine, as well as the potential effects of a headspace in the incubation vessel, isotope saturation occurred at a leucine concentration of above about 50 nM in both ode and anoxic waters from all three lakes. Leucine incorporation rates were linearly correlated to observed growth, and there was no significant difference between oxic and anoxic conditions. O-2 contamination of anoxic water during I-h incubations with leucine had no detectable impact on the incorporation rate, while a headspace in the incubation vessel caused leucine incorporation to increase in both anoxic and O-2-contaminated samples. The results indicate that the leucine incorporation method relates equally to bacterial growth rates under oxic and anoxic conditions and that incubation should be performed without a headspace.

  • 38.
    Bastviken, David
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Tranvik, Lars J.
    Uppsala universitet.
    Downing, John A.
    Iowa State University.
    Crill, Patrick M.
    Stockholms universitet.
    Enrich-Prast, Alex
    University of Rio de Janeiro.
    Freshwater Methane Emissions Offset the Continental Carbon Sink2011In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 331, no 6013, p. 50-50Article in journal (Refereed)
    Abstract [en]

    Inland waters (lakes, reservoirs, streams, and rivers) are often substantial methane (CH4) sources in the terrestrial landscape. They are, however, not yet well integrated in global greenhouse gas (GHG) budgets. Data from 474 freshwater ecosystems and the most recent global water area estimates indicate that freshwaters emit at least 103 teragrams of CH4 year−1, corresponding to 0.65 petagrams of C as carbon dioxide (CO2) equivalents year−1, offsetting 25% of the estimated land carbon sink. Thus, the continental GHG sink may be considerably overestimated, and freshwaters need to be recognized as important in the global carbon cycle.

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  • 39.
    Bastviken, David
    et al.
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Treat, Claire C.
    Helmholtz Ctr Polar & Marine Res, Germany.
    Pangala, Sunitha Rao
    Univ Lancaster, England.
    Gauci, Vincent
    Univ Birmingham, England; Univ Birmingham, England.
    Enrich Prast, Alex
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences. Fed Univ Sao Paulo IMar UNIFESP, Brazil; Univ Fed Rio De Janeiro, Brazil.
    Karlson, Martin
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences. Linköping University, Centre for Climate Science and Policy Research, CSPR.
    Gålfalk, Magnus
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Brandini Romano, Mariana
    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.
    The importance of plants for methane emission at the ecosystem scale2023In: Aquatic Botany, ISSN 0304-3770, E-ISSN 1879-1522, Vol. 184, article id 103596Article in journal (Refereed)
    Abstract [en]

    Methane (CH4), one of the key long-lived atmospheric greenhouse gases, is primarily produced from organic matter. Accordingly, net primary production of organic matter sets the boundaries for CH4 emissions. Plants, being dominant primary producers, are thereby indirectly sustaining most global CH4 emissions, albeit with delays in time and with spatial offsets between plant primary production and subsequent CH4 emission. In addition, plant communities can enhance or hamper ecosystem production, oxidation, and transport of CH4 in multiple ways, e.g., by shaping carbon, nutrient, and redox gradients, and by representing a physical link be-tween zones with extensive CH4 production in anoxic sediments or soils and the atmosphere. This review focuses on how plants and other primary producers influence CH4 emissions with the consequences at ecosystem scales. We outline mechanisms of interactions and discuss flux regulation, quantification, and knowledge gaps across multiple ecosystem examples. Some recently proposed plant-related ecosystem CH4 fluxes are difficult to reconcile with the global atmospheric CH4 budget and the enigmas related to these fluxes are highlighted. Overall, ecosystem CH4 emissions are strongly linked to primary producer communities, directly or indirectly, and properly quantifying magnitudes and regulation of these links are key to predicting future CH4 emissions in a rapidly changing world.

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  • 40.
    Bastviken, David
    et al.
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Wilk, Julie
    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.
    Gålfalk, Magnus
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Karlson, Martin
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Schmid Neset, Tina
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Opach, Tomasz
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences. Norwegian Univ Sci & Technol NTNU, Norway.
    Enrich Prast, Alex
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences. Linköping University, Biogas Research Center. Univ Fed Rio de Janeiro, Brazil.
    Sundgren, Ingrid
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Critical method needs in measuring greenhouse gas fluxes2022In: Environmental Research Letters, E-ISSN 1748-9326, Vol. 17, no 10, article id 104009Article in journal (Refereed)
    Abstract [en]

    Reaching climate goals depends on appropriate and accurate methods to quantify greenhouse gas (GHG) fluxes and to verify that efforts to mitigate GHG emissions are effective. We here highlight critical advantages, limitations, and needs regarding GHG flux measurement methods, identified from an analysis of &gt;13 500 scientific publications regarding three long-lived GHGs, carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). While existing methods are well-suited for assessing atmospheric changes and local fluxes, they are expensive and have limited accessibility. Further, we are typically forced to choose between methods for very local GHG sources and sinks and their regulation (m(2)-scaled measurements), or methods for aggregated net fluxes at &gt;ha or km(2) scales measurements. The results highlight the key need of accessible and affordable GHG flux measurement methods for the many flux types not quantifiable from fossil fuel use, to better verify inventories and mitigation efforts for transparency and accountability under the Paris agreement. The situation also calls for novel methods, capable of quantifying large scale GHG flux patterns while simultaneously distinguishing local source and sink dynamics and reveal flux regulation, representing key knowledge for quantitative GHG flux modeling. Possible strategies to address the identified GHG flux measurement method needs are discussed. The analysis also generated indications of how GHG flux measurements have been distributed geographically and across flux types, which are reported.

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  • 41.
    Bastviken, David
    et al.
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Wilk, Julie
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences. Linköping University, Centre for Climate Science and Policy Research, CSPR.
    Nguyen, Thanh Duc
    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.
    Karlson, Martin
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences. Linköping University, Centre for Climate Science and Policy Research, CSPR.
    Schmid Neset, Tina-Simone
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences. Linköping University, Centre for Climate Science and Policy Research, CSPR.
    Opach, Tomasz
    Dept. of Geography, Norwegian University of Science and Technology, Trondheim, Norway.
    Enrich Prast, Alex
    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.
    Measuring greenhouse gas fluxes: what methods do we have versus what methods do we need?2022Conference paper (Other academic)
    Abstract [en]

    Appropriate methods to measure greenhouse gas (GHG) fluxes are critical for our ability to detect fluxes, understand regulation, make adequate priorities for climate change mitigation efforts, and verify that these efforts are effective. Ideally, we need reliable, accessible, and affordable measurements at relevant scales. We surveyed present GHG flux measurement methods, identified from an analysis of >11000 scientific publications and a questionnaire to sector professionals and analysed method pros and cons versus needs for novel methodology. While existing methods are well-suited for addressing certain questions, this presentation presents fundamental limitations relative to GHG flux measurement needs for verifiable and transparent action to mitigate many types of emissions. Cost and non-academic accessibility are key aspects, along with fundamental measurement performance. These method limitations contribute to the difficulties in verifying GHG mitigation efforts for transparency and accountability under the Paris agreement. Resolving this mismatch between method capacity and societal needs is urgently needed for effective climate mitigation. This type of methodological mismatch is common but seems to get high priority in other knowledge domains. The obvious need to prioritize development of accurate diagnosis methods for effective treatments in healthcare is one example. This presentation provides guidance regarding the need to prioritize the development of novel GHG flux measurement methods.

  • 42.
    Bengtson, P.
    et al.
    Lund University, Sweden.
    Bastviken, David
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    de Boer, W.
    Centre for Terrestrial Ecology, Netherlands.
    Öberg, Gunilla
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Possible role of reactive chlorine in microbial antagonism and organic matter chlorination in terrestrial environments2009In: Environmental Microbiology, ISSN 1462-2912, E-ISSN 1462-2920, Vol. 11, no 6, p. 1330-1339Article in journal (Refereed)
    Abstract [en]

    Several studies have demonstrated that extensive formation of organically bound chlorine occurs both in soil and in decaying plant material. Previous studies suggest that enzymatic formation of reactive chlorine outside cells is a major source. However, the ecological role of microbial-induced extracellular chlorination processes remains unclear. In the present paper, we assess whether or not the literature supports the hypothesis that extracellular chlorination is involved in direct antagonism against competitors for the same resources. Our review shows that it is by no means rare that biotic processes create conditions that render biocidal concentrations of reactive chlorine compounds, which suggest that extracellular production of reactive chlorine may have an important role in antagonistic microbial interactions. To test the validity, we searched the UniprotPK database for microorganisms that are known to produce haloperoxidases. It appeared that many of the identified haloperoxidases from terrestrial environments are originating from organisms that are associated with living plants or decomposing plant material. The results of the in silico screening were supported by various field and laboratory studies on natural chlorination. Hence, the ability to produce reactive chlorine seems to be especially common in environments that are known for antibiotic-mediated competition for resources (interference competition). Yet, the ability to produce haloperoxidases is also recorded, for example, for plant endosymbionts and parasites, and there is little or no empirical evidence that suggests that these organisms are antagonistic.

  • 43.
    Bengtson, Per
    et al.
    Lund University, Sweden .
    Bastviken, David
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Oeberg, Gunilla
    University of British Columbia, Canada .
    Possible roles of reactive chlorine II: assessing biotic chlorination as a way for organisms to handle oxygen stress2013In: Environmental Microbiology, ISSN 1462-2912, E-ISSN 1462-2920, Vol. 15, no 4, p. 991-1000Article, review/survey (Refereed)
    Abstract [en]

    Natural formation of organically bound chlorine is extensive in many environments. The enzymes associated with the formation of chlorinated organic matter are produced by a large variety of organisms. Little is known about the ecological role of the process, the key question being: why do microorganisms promote chlorination of organic matter? In a recent paper we discuss whether organic matter chlorination may be a result of antagonistic interactions among microorganisms. In the present paper we evaluate whether extracellular microbial formation of reactive chlorine may be used as a defence against oxygen stress, and we discuss whether this process is likely to contribute to the formation of chlorinated organic matter. Our analysis suggests that periodic exposure to elevated concentrations of reactive oxygen species is a common denominator among the multitude of organisms that are able to enzymatically catalyse formation of reactive chlorine. There is also some evidence suggesting that the production of such enzymes in algae and bacteria is induced by oxygen stress. The relative contribution from this process to the extensive formation of chlorinated organic matter in natural environments remains to be empirically assessed.

  • 44.
    Bertassoli, Dailson J. Jr.
    et al.
    Univ Sao Paulo, Brazil; Univ Sao Paulo, Brazil.
    Sawakuchi, Henrique
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    de Araujo, Kleiton R.
    Fed Univ Para, Brazil.
    de Camargo, Marcelo G. P.
    Univ Sao Paulo, Brazil.
    Alem, Victor A. T.
    Univ Sao Paulo, Brazil.
    Pereira, Tatiana S.
    Fed Univ Para, Brazil.
    Krusche, Alex V
    Univ Sao Paulo, Brazil.
    Bastviken, David
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Richey, Jeffrey E.
    Univ Sao Paulo, Brazil; Univ Washington, WA 98195 USA.
    Sawakuchi, Andre O.
    Univ Sao Paulo, Brazil.
    How green can Amazon hydropower be?: Net carbon emission from the largest hydropower plant in Amazonia2021In: Science Advances, E-ISSN 2375-2548, Vol. 7, no 26, article id eabe1470Article in journal (Refereed)
    Abstract [en]

    The current resurgence of hydropower expansion toward tropical areas has been largely based on run-of-the-river (ROR) dams, which are claimed to have lower environmental impacts due to their smaller reservoirs. The Belo Monte dam was built in Eastern Amazonia and holds the largest installed capacity among ROR power plants worldwide. Here, we show that postdamming greenhouse gas (GHG) emissions in the Belo Monte area are up to three times higher than preimpoundment fluxes and equivalent to about 15 to 55 kg CO(2)eq MWh(-1). Since per-area emissions in Amazonian reservoirs are significantly higher than global averages, reducing flooded areas and prioritizing the power density of hydropower plants seem to effectively reduce their carbon footprints. Nevertheless, total GHG emissions are substantial even from this leading-edge ROR power plant. This argues in favor of avoiding hydropower expansion in Amazonia regardless of the reservoir type.

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  • 45.
    Björn, Annika
    et al.
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Svensson, Teresia
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Bastviken, David
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Öberg, Gunilla
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Problem-oriented laboratory work in environmental education: Experiences from a new master´s programme at Linköping Univerity, Sweden1999In: AuDes 5th Conference on Environmental Education, 1999Conference paper (Other academic)
  • 46.
    Bäckstrand, Kristina
    et al.
    Stockholm University.
    Crill, P. M.
    Stockholm University.
    Jackowicz-Korczyñski, M.
    Lund University.
    Mastepanov, M.
    Lund University.
    Christensen, T. R.
    Lund University.
    Bastviken, David
    Department of Geology and Geochemistry, Stockholm University.
    Annual carbon gas budget for a subarctic peatland, northern Sweden2010In: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 7, p. 95-108Article in journal (Other academic)
    Abstract [en]

     Temperatures in the Arctic regions are rising, thawing permafrost and exposing previously stable soil organic carbon (OC) to decomposition. This can result in northern latitude soils, which have accumulated large amounts of OC potentially shifting from atmospheric C sinks to C sources with positive feedback on climate warming. In this paper, we estimate the annual net C gas balance (NCB) of the subarctic mire Stordalen, based on automatic chamber measurements of CO2 and total hydrocarbon (THC; CH4 and NMVOCs) exchange. We studied the dominant vegetation communities with different moisture and permafrost characteristics; a dry Palsa underlain by permafrost, an intermediate thaw site with Sphagnum spp. and a wet site with Eriophorum spp. where the soil thaws completely. Whole year accumulated fluxes of CO2 were estimated to 29.7, −35.3 and −34.9 gC m−2 respectively for the Palsa, Sphagnum and Eriophorum sites (positive flux indicates an addition of C to the atmospheric pool). The corresponding annual THC emissions were 0.5, 6.2 and 31.8 gC m−2 for the same sites. Therefore, the NCB for each of the sites was 30.2, −29.1 and −3.1 gC m−2 respectively for the Palsa, Sphagnum and Eriophorum site. On average, the whole mire was a CO2 sink of 2.6 gC m−2 and a THC source of 6.4 gC m−2 over a year. Consequently, the mire was a net source of C to the atmosphere by 3.9 gC m−2 (based on area weighted estimates for each of the three plant communities). Early and late snow season efflux of CO2 and THC emphasize the importance of winter measurements for complete annual C budgets. Decadal vegetation changes at Stordalen indicate that both the productivity and the THC emissions increased between 1970 and 2000. Considering the GWP100 of CH4, the net radiative forcing on climate increased 21% over the same time. In conclusion, reduced C compounds in these environments have high importance for both the annual C balance and climate.

  • 47.
    Carpenter, Stephen R.
    et al.
    Center for Limnology, University of Wisconsin, Madison, Wisconsin, USA.
    Cole, Jonathan J.
    Institute of Ecosystem Studies, Millbrook, New York, USA.
    Pace, Michael L.
    Institute of Ecosystem Studies, Millbrook, New York, USA.
    Van de Bogert, Matthew
    Center for Limnology, University of Wisconsin, Madison, Wisconsin, USA; Institute of Ecosystem Studies, Millbrook, New York, USA.
    Bade, Darrren L.
    Center for Limnology, University of Wisconsin, Madison, Wisconsin, USA; Institute of Ecosystem Studies, Millbrook, New York, USA.
    Bastviken, David
    Linköping University, Department of Thematic Studies, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Gille, Caitlin M.
    Center for Limnology, University of Wisconsin, Madison, Wisconsin, USA.
    Hodgson, James R.
    Department of Biology, St. Norbert College, De Pere, Wisconsin, USA.
    Kitchell, James F.
    Center for Limnology, University of Wisconsin, Madison, Wisconsin, USA.
    Kritzberg, Emma S.
    Department of Ecology/Limnology, Lund University, Lund, Sweden.
    Ecosystem subsidies: Terrestrial support of aquatic food webs from C-13 addition to contrasting lakes2005In: Ecology, ISSN 0012-9658, E-ISSN 1939-9170, Vol. 86, no 10, p. 2737-2750Article in journal (Refereed)
    Abstract [en]

    Whole-lake additions of dissolved inorganic C-13 were used to measure allochthony (the terrestrial contribution of organic carbon to aquatic consumers) in two unproductive lakes (Paul and Peter Lakes in 2001), a nutrient-enriched lake (Peter Lake in 2002), and a dystrophic lake (Tuesday Lake in 2002). Three kinds of dynamic models were used to estimate allochthony: a process-rich, dual-isotope flow model based on mass balances of two carbon isotopes in 12 carbon pools; simple univariate time-series models driven by observed time courses of delta(13)CO(2); and multivariate autoregression models that combined information from time series of delta(13)C in several interacting carbon pools. All three models gave similar estimates of allochthony. In the three experiments without nutrient enrichment, flows of terrestrial carbon to dissolved and particulate organic carbon, zooplankton, Chaoborus, and fishes were substantial. For example, terrestrial sources accounted for more than half the carbon flow to juvenile and adult largemouth bass, pumpkinseed sunfish, golden shiners, brook sticklebacks, and fathead minnows in the unenriched experiments. Allochthony was highest in the dystrophic lake and lowest in the nutrient-enriched lake. Nutrient enrichment of Peter Lake decreased allochthony of zooplankton from 0.34-0.48 to 0-0.12, and of fishes from 0.51-0.80 to 0.25-0.55. These experiments show that lake ecosystem carbon cycles, including carbon flows to consumers, are heavily subsidized by organic carbon from the surrounding landscape.

  • 48.
    Chmiel, Hannah E.
    et al.
    Uppsala University, Sweden.
    Kokic, Jovana
    Uppsala University, Sweden.
    Denfeld, Blaize A.
    Uppsala University, Sweden.
    Einarsdottir, Karolina
    Uppsala University, Sweden.
    Wallin, Marcus B.
    Uppsala University, Sweden.
    Koehler, Birgit
    Uppsala University, Sweden.
    Isidorova, Anastasija
    Uppsala University, Sweden.
    Bastviken, David
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Ferland, Marie-Eve
    University of Quebec, Canada.
    Sobek, Sebastian
    Uppsala University, Sweden.
    The role of sediments in the carbon budget of a small boreal lake2016In: Limnology and Oceanography, ISSN 0024-3590, E-ISSN 1939-5590, Vol. 61, no 5, p. 1814-1825Article in journal (Refereed)
    Abstract [en]

    We investigated the role of lake sediments as carbon (C) source and sink in the annual C budget of a small (0.07 km(2)) and shallow (mean depth, 3.4 m), humic lake in boreal Sweden. Organic carbon (OC) burial and mineralization in the sediments were quantified from Pb-210-dated sediment and laboratory sediment incubation experiments, respectively. Burial and mineralization rates were then upscaled to the entire basin and to one whole year using sediment thickness derived from sub-bottom profiling, basin morphometry, and water column monitoring data of temperature and oxygen concentration. Furthermore, catchment C import, open water metabolism, photochemical mineralization as well as carbon dioxide (CO2) and methane (CH4) emissions to the atmosphere were quantified to relate sediment processes to other lake C fluxes. We found that on a whole-basin and annual scale, sediment OC mineralization was three times larger than OC burial, and contributed about 16% to the annual CO2 emission. Other contributions to CO2 emission were water column metabolism (31%), photochemical mineralization (6%), and catchment imports via inlet streams and inflow of shallow groundwater (22%). The remainder (25%) could not be explained by our flux calculations, but was most likely attributed to an underestimation in groundwater inflow. We conclude that on an annual and whole-basin scale (1) sediment OC mineralization dominated over OC burial, (2) water column OC mineralization contributed more to lake CO2 emission than sediment OC mineralization, and (3) catchment import of C to the lake was greater than lake-internal C cycling.

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  • 49.
    Cole, Jonathan J
    et al.
    Cary Institute of Ecosystem Studies, Millbrook, NY.
    Bade, Darren L.
    Kent State University, Kent, OH.
    Bastviken, David
    Linköping University, Department of Thematic Studies, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Pace, Michael L.
    University of Virginia, Charlottesville, VA.
    Van de Bogert, Matthew
    Center for Limnology, University of Wisconsin, Madison, WI.
    Multiple approaches to estimating air-water gas exchange in small lakes2010In: Limnology and Oceanography: Methods, E-ISSN 1541-5856, Vol. 8, p. 285-293Article in journal (Refereed)
    Abstract [en]

    The rate of gas exchange between air and water is an essential quantity in a number of contexts, from mass balances to the calculation of whole-system metabolism. The exchange of a gas between water and the atmosphere is controlled by differential partial pressures of gases in air and in water (both straightforward to measure) and by the amount of turbulent energy exchange between the air-water interface, the measurement of which is neither simple nor direct. This physical exchange is often expressed as a piston velocity (k). We compared four methods for estimating k in a series of small (0.3 to 45 ha), low-wind (mean wind < 3 m s–1) lakes: 1) floating chambers using ambient CH4; 2) whole-lake SF6 additions; 3) three wind-based models from the literature; and 4) C mass balances constrained by whole-lake 13C additions. All of the methods, with the exception of one windbased model, converged on values for k600 of between 0.35 and 0.74 m d–1 with no biases among methods. The floating chambers, if designed properly, are a cost-effective way of obtaining site-specific values of k for low wind lakes over fairly short time frames (hours).

  • 50.
    de Boer, Wietse
    et al.
    Netherlands Institute of Ecology.
    Folman, Larissa B.
    Netherlands Institute of Ecology.
    Klein Gunnewiek, Paulien J.A.
    Netherlands Institute of Ecology.
    Svensson, Teresia
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Bastviken, David
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    Öberg, Gunilla
    Linköping University, The Tema Institute, Department of Water and Environmental Studies. Linköping University, Faculty of Arts and Sciences.
    del Rio, José C.
    Instituto de Recursos Naturales y Agrobiología de Sevilla.
    Boddy, Lynne
    Cardiff School of Biosciences.
    Mechanism of antibacterial activity of the white-rot fungus Hypholoma fasciculare colonizing wood2010In: Canadian journal of microbiology (Print), ISSN 0008-4166, E-ISSN 1480-3275, Vol. 56, no 5, p. 380-388Article in journal (Other academic)
    Abstract [en]

    In a previous study it was shown that the number of wood-inhabiting bacteria was drastically reduced after colonization of beech (Fagus sylvatica) wood blocks by the white-rot fungus Hypholoma fasciculare, or sulfur tuft (Folman et al. 2008). Here we report on the mechanisms of this fungal-induced antibacterial activity. Hypholoma fasciculare was allowed to invade beech and pine (Pinus sylvestris) wood blocks that had been precolonized by microorganisms from forest soil. The changes in the number of bacteria, fungal biomass, and fungal-related wood properties were followed for 23 weeks. Colonization by the fungus resulted in a rapid and large reduction in the number of bacteria (colony-forming units), which was already apparent after 4 weeks of incubation. The reduction in the number of bacteria coincided with fungal-induced acidification in both beech and pine wood blocks. No evidence was found for the involvement of toxic secondary metabolites or reactive oxygen species in the reduction of the number of bacteria. Additional experiments showed that the dominant bacteria present in the wood blocks were not able to grow under the acidic conditions (pH 3.5) created by the fungus. Hence our research pointed at rapid acidification as the major factor causing reduction of wood-inhabiting bacteria upon colonization of wood by H. fasciculare.

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