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Publications (10 of 16) Show all publications
Gudasz, C., Ruppenthal, M., Kalbitz, K., Cerli, C., Fiedler, S., Oelmann, Y., . . . Karlsson, J. (2017). Contributions of terrestrial organic carbon to northern lake sediments. Limnology and Oceanography Letters, 2(6), 218-227
Open this publication in new window or tab >>Contributions of terrestrial organic carbon to northern lake sediments
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2017 (English)In: Limnology and Oceanography Letters, E-ISSN 2378-2242, Vol. 2, no 6, p. 218-227Article in journal (Refereed) Published
Abstract [en]

Sediments of northern lakes sequester large amounts of organic carbon (OC), but direct evidence of the relative importance of their sources is lacking. We used stable isotope ratios of nonexchangeable hydrogen (delta H-2(n)) in topsoil, algae, and surface sediments in order to measure the relative contribution of terrestrial OC in surface sediments of 14 mountainous arctic and lowland boreal lakes in Sweden. The terrestrial contribution to the sediment OC pool was on average 66% (range 46-80) and similar between arctic and boreal lakes. Proxies for the supply of terrestrial and algal OC explained trends in the relative contribution of terrestrial OC across lakes. However, the data suggest divergent predominant sources for terrestrial OC of sediments in Swedish lakes, with dissolved matter dominating in lowland boreal lakes and particulate OC in mountainous arctic lakes.

National Category
Ecology
Identifiers
urn:nbn:se:uu:diva-389481 (URN)10.1002/lol2.10051 (DOI)000456695500004 ()
Funder
Swedish Research Council Formas, 942-2015-1070
Available from: 2019-07-16 Created: 2019-07-16 Last updated: 2022-04-29Bibliographically approved
Sobek, S., Gudasz, C., Koehler, B., Tranvik, L. J., Bastviken, D. & Morales-Pineda, M. (2017). Temperature Dependence of Apparent Respiratory Quotients and Oxygen Penetration Depth in Contrasting Lake Sediments. Journal of Geophysical Research - Biogeosciences, 122(11), 3076-3087
Open this publication in new window or tab >>Temperature Dependence of Apparent Respiratory Quotients and Oxygen Penetration Depth in Contrasting Lake Sediments
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2017 (English)In: Journal of Geophysical Research - Biogeosciences, ISSN 2169-8953, E-ISSN 2169-8961, Vol. 122, no 11, p. 3076-3087Article in journal (Refereed) Published
Abstract [en]

Lake sediments constitute an important compartment in the carbon cycle of lakes, by burying carbon over geological timescales and by production and emission of greenhouse gases. The degradation of organic carbon (OC) in lake sediments is linked to both temperature and oxygen (O2), but the interactivenature of this regulation has not been studied in lake sediments in a quantitative way. We present the first systematic investigation of the effects of temperature on the apparent respiratory quotient (RQ, i.e., the molar ratio between carbon dioxide (CO2) production and O2 consumption) in two contrasting lake sediments. Laboratory incubations of sediment cores of a humic lake and an eutrophic lake across a 1–21°C temperature gradient over 157 days revealed that both CO2 production and O2 consumption were positively, exponentially, and similarly dependent on temperature. The apparent RQ differed significantly between the lake sediments (0.63 ± 0.26 and 0.99 ± 0.28 in the humic and the eutrophic lake, respectively; mean ± SD) and was significantly and positively related to temperature. The O2 penetration depth into the sediment varied by a factor of 2 over the 1–21°C temperature range and was significantly, negatively, and similarly related to temperature in both lake sediments. Accordingly, increasing temperature may influence the overall extent of OC degradation in lake sediments by limiting O2 supply to aerobic microbial respiration to the topmost sediment layer, resulting in a concomitant shift to less effective anaerobic degradation pathways. This suggests that temperature may represent a key controlling factor of the OC burial efficiency in lake sediments.

Place, publisher, year, edition, pages
American Geophysical Union (AGU), 2017
National Category
Geochemistry
Identifiers
urn:nbn:se:uu:diva-336859 (URN)10.1002/2017JG003833 (DOI)000418086800024 ()
Available from: 2017-12-18 Created: 2017-12-18 Last updated: 2020-01-28Bibliographically approved
Seekell, D. A. & Gudasz, C. (2016). Long-term pCO(2) trends in Adirondack Lakes. Geophysical Research Letters, 43(10), 5109-5115
Open this publication in new window or tab >>Long-term pCO(2) trends in Adirondack Lakes
2016 (English)In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 43, no 10, p. 5109-5115Article in journal (Refereed) Published
Abstract [en]

Lakes are globally significant sources of CO2 to the atmosphere. However, there are few temporally resolved records of lake CO2 concentrations and long-term patterns are poorly characterized. We evaluated annual trends in the partial pressure of CO2 (pCO(2)) based on chemical measurements from 31 Adirondack Lakes taken monthly over an 18 year period. All lakes were supersaturated with CO2 and were sources of CO2 to the atmosphere. There were significant pCO2 trends in 29% of lakes. The median magnitude of significant positive trends was 32.1 mu atm yr(-1). Overall, 52% of lakes had pCO(2) trends greater than those reported for the atmosphere and ocean. Significant trends in lake pCO(2) were attributable to regional recovery from acid deposition and changing patterns of ice cover. These results illustrate that lake pCO(2) can respond rapidly to environmental change, but the lack of significant trend in 71% of lakes indicates substantial lake-to-lake variation in magnitude of response.

National Category
Oceanography, Hydrology and Water Resources Geochemistry
Identifiers
urn:nbn:se:uu:diva-299792 (URN)10.1002/2016GL068939 (DOI)000378347500055 ()
Funder
Carl Tryggers foundation
Available from: 2016-07-28 Created: 2016-07-27 Last updated: 2020-01-28Bibliographically approved
Steger, K., Premke, K., Gudasz, C., Boschker, H. T. & Tranvik, L. J. J. (2015). Comparative study on bacterial carbon sources in lake sediments: the role of methanotrophy. Aquatic Microbial Ecology, 76(1), 39-47
Open this publication in new window or tab >>Comparative study on bacterial carbon sources in lake sediments: the role of methanotrophy
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2015 (English)In: Aquatic Microbial Ecology, ISSN 0948-3055, E-ISSN 1616-1564, Vol. 76, no 1, p. 39-47Article in journal (Refereed) Published
Abstract [en]

Methane-derived carbon can be important in both benthic and pelagic food webs. Either generated in the anaerobic layers of the sediment or in the anaerobic hypolimnion of stratified eutrophic lakes, methane is an excellent carbon source for aerobic methanotrophic bacteria. The very negative methane delta C-13-signal in the methanotrophic biomass provides an excellent opportunity to trace the use of methane-derived carbon in food webs. We studied carbon sources of benthic bacteria in a range of Swedish lakes with different inputs of terrestrial organic carbon and indigenous primary production. We analyzed the C-13:C-12 ratios in phospholipid-derived fatty acids, which serve as biomarkers for specific groups of Bacteria. We demonstrate that methane is an important carbon source for sediment bacteria, not only for the methanotrophic community but also for the non-methanotrophic heterotrophic bacteria. This most likely indirect utilization of isotopically highly depleted methane masks the stable isotope signatures for terrestrial input and local primary production in the heterotrophic bacterial community.

Keywords
Benthic microbes, Boreal lakes, Methanotrophic bacteria, Phospholipid-derived fatty acid, PLFA, Stable isotopes
National Category
Biological Sciences
Identifiers
urn:nbn:se:uu:diva-265605 (URN)10.3354/ame01766 (DOI)000362667300004 ()
Funder
Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning
Available from: 2015-11-02 Created: 2015-11-02 Last updated: 2020-01-28Bibliographically approved
Gudasz, C., Sobek, S., Bastviken, D., Köhler, B. & Tranvik, L. J. (2015). Temperature sensitivity of organic carbon mineralization in contrasting lake sediments. Journal of Geophysical Research - Biogeosciences, 120(7), 1215-1225
Open this publication in new window or tab >>Temperature sensitivity of organic carbon mineralization in contrasting lake sediments
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2015 (English)In: Journal of Geophysical Research - Biogeosciences, ISSN 2169-8953, E-ISSN 2169-8961, Vol. 120, no 7, p. 1215-1225Article in journal (Refereed) Published
Abstract [en]

Temperature alone explains a great amount of variation in sediment organic carbon (OC) mineralization. Studies on decomposition of soil OC suggest that (1) temperature sensitivity differs between the fast and slowly decomposition OC and (2) over time, decreasing soil respiration is coupled with increase in temperature sensitivity. In lakes, autochthonous and allochthonous OC sources are generally regarded as fast and slowly decomposing OC, respectively. Lake sediments with different contributions of allochthonous and autochthonous components, however, showed similar temperature sensitivity in short-term incubation experiments. Whether the mineralization of OC in lake sediments dominated by allochthonous or autochthonous OC has different temperature sensitivity in the longer term has not been addressed. We incubated sediments from two boreal lakes that had contrasting OC origin (allochthonous versus autochthonous), and OC characteristics (C/N ratios of 21 and 10) at 1, 3, 5, 8, 13, and 21 degrees C for five months. Compared to soil and litter mineralization, sediment OC mineralization rates were low in spite of low apparent activation energy (E-a). The fraction of the total OC pool that was lost during five months varied between 0.4 and 14.8%. We estimate that the sediment OC pool not becoming long-term preserved was degraded with average apparent turnover times between 3 and 32years. While OC mineralization was strongly dependent on temperature as well as on OC composition and origin, temperature sensitivity was similar across lakes and over time. We suggest that the temperature sensitivity of OC mineralization in lake sediments is similar across systems within the relevant seasonal scales of OC supply and degradation.

Keywords
lake sediment, mineralization, organic carbon, temperature sensitivity, turnover time
National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:uu:diva-262446 (URN)10.1002/2015JG002928 (DOI)000359868200003 ()
Funder
Swedish Research Council FormasKnut and Alice Wallenberg Foundation
Available from: 2015-09-15 Created: 2015-09-15 Last updated: 2020-01-28Bibliographically approved
Osman, O., Gudasz, C. & Bertilsson, S. (2014). Diversity and abundance of aromatic catabolic genes in lake sediments in response to temperature change. FEMS Microbiology Ecology, 88(3), 468-481
Open this publication in new window or tab >>Diversity and abundance of aromatic catabolic genes in lake sediments in response to temperature change
2014 (English)In: FEMS Microbiology Ecology, ISSN 0168-6496, E-ISSN 1574-6941, Vol. 88, no 3, p. 468-481Article in journal (Refereed) Published
Abstract [en]

The abundance and composition of genes involved in the catabolism of aromatic compounds provide important information on the biodegradation potential of organic pollutants and naturally occurring compounds in the environment. We studied catechol 2, 3 dioxygenase (C23O) and benzylsuccinate synthase (bssA) genes coding for key enzymes of aerobic and anaerobic degradation of aromatic compounds in experimental incubations with sediments from two contrasting lakes; humic lake Svarttjärn and eutrophic Vallentunasjön, respectively. Sediment cores from both lakes were incubated continuously for 5 months at constant temperatures ranging from 1.0 to 21.0 °C. The difference in C23O gene composition of the sediment analyzed at the end of the experiment was larger between lakes, than among temperature treatments within each lake. The abundance of C23O gene copies and measured respiration was positively correlated with temperature in Vallentunasjön, whereas putative C23O genes were present in lower concentrations in Svarttjärn sediments. Putative bssA genes were only detected in Svarttjärn. For both lakes, the two catabolic genes were most abundant in the surface sediment. The results emphasize the important role of temperature and nutrient availability in controlling the functional potential of sediment microorganisms and reveal differences between systems with contrasting trophic status. A better understanding of catabolic pathways and enzymes will enable more accurate forecasting of the functional properties of ecosystems under various scenarios of environmental change.

Keywords
cathecol 2, 3 dioxygenase, bensynsuccinate synthase, biodegradation, bacterial communities, quantitative PCR;T-RFLP
National Category
Genetics
Identifiers
urn:nbn:se:uu:diva-225305 (URN)10.1111/1574-6941.12312 (DOI)000337590500004 ()
Available from: 2014-05-31 Created: 2014-05-31 Last updated: 2020-01-28Bibliographically approved
Marotta, H., Pinho, L., Gudasz, C., Bastviken, D., Tranvik, L. J. & Enrich-Prast, A. (2014). Greenhouse gas production in low-latitude lake sediments responds strongly to warming. Nature Climate Change, 4(6), 467-470
Open this publication in new window or tab >>Greenhouse gas production in low-latitude lake sediments responds strongly to warming
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2014 (English)In: Nature Climate Change, ISSN 1758-678X, E-ISSN 1758-6798, Vol. 4, no 6, p. 467-470Article in journal (Refereed) Published
Abstract [en]

Inland water sediments receive large quantities of terrestrial organic matter(1-5) and are globally important sites for organic carbon preservation(5,6). Sediment organic matter mineralization is positively related to temperature across a wide range of high-latitude ecosystems(6-10), but the situation in the tropics remains unclear. Here we assessed temperature effects on the biological production of CO2 and CH4 in anaerobic sediments of tropical lakes in the Amazon and boreal lakes in Sweden. On the basis of conservative regional warming projections until 2100 (ref. 11), we estimate that sediment CO2 and CH4 production will increase 9-61% above present rates. Combining the CO2 and CH4 as CO2 equivalents (CO(2)eq; ref. 11), the predicted increase is 2.4-4.5 times higher in tropical than boreal sediments. Although the estimated lake area in low latitudes is 3.2 times smaller than that of the boreal zone, we estimate that the increase in gas production from tropical lake sediments would be on average 2.4 times higher for CO2 and 2.8 times higher for CH4. The exponential temperature response of organic matter mineralization, coupled with higher increases in the proportion of CH4 relative to CO2 on warming, suggests that the production of greenhouse gases in tropical sediments will increase substantially. This represents a potential large-scale positive feedback to climate change.

National Category
Ecology Environmental Sciences Meteorology and Atmospheric Sciences
Identifiers
urn:nbn:se:uu:diva-228465 (URN)10.1038/NCLIMATE2222 (DOI)000337138700022 ()
Available from: 2014-07-16 Created: 2014-07-15 Last updated: 2020-01-28Bibliographically approved
Yvon-Durocher, G., Allen, A. P., Bastviken, D., Conrad, R., Gudasz, C., St-Pierre, A., . . . del Giorgio, P. A. (2014). Methane fluxes show consistent temperature dependence across microbial to ecosystem scales. Nature, 507(7493), 488-491
Open this publication in new window or tab >>Methane fluxes show consistent temperature dependence across microbial to ecosystem scales
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2014 (English)In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 507, no 7493, p. 488-491Article in journal (Refereed) Published
Abstract [en]

Methane (CH4) is an important greenhouse gas because it has 25 times the global warming potential of carbon dioxide (CO2) by mass over a century(1). Recent calculations suggest that atmospheric CH4 emissions have been responsible for approximately 20% of Earth's warming since pre-industrial times(2). Understanding how CH4 emissions from ecosystems will respond to expected increases in global temperature is therefore fundamental to predicting whether the carbon cycle will mitigate or accelerate climate change. Methanogenesis is the terminal step in the remineralization of organic matter and is carried out by strictly anaerobic Archaea(3). Like most other forms of metabolism, methanogenesis is temperature-dependent(4,5). However, it is not yet known how this physiological response combines with other biotic processes (for example, methanotrophy(6), substrate supply(3,7), microbial community composition(8)) and abiotic processes (for example, water-table depth(9,10)) to determine the temperature dependence of ecosystem-level CH4 emissions. It is also not known whether CH4 emissions at the ecosystem level have a fundamentally different temperature dependence than other key fluxes in the carbon cycle, such as photosynthesis and respiration. Here we use meta-analyses to show that seasonal variations in CH4 emissions from a wide range of ecosystems exhibit an average temperature dependence similar to that of CH4 production derived from pure cultures of methanogens and anaerobic microbial communities. This average temperature dependence (0.96 electron volts (eV)), which corresponds to a 57-fold increase between 0 and 30 degrees C, is considerably higher than previously observed for respiration (approximately 0.65 eV)(11) and photosynthesis (approximately 0.3 eV)(12). As a result, we show that both the emission of CH4 and the ratio of CH4 to CO2 emissions increase markedly with seasonal increases in temperature. Our findings suggest that global warming may have a large impact on the relative contributions of CO2 and CH4 to total greenhouse gas emissions from aquatic ecosystems, terrestrial wetlands and rice paddies.

National Category
Natural Sciences
Identifiers
urn:nbn:se:uu:diva-224361 (URN)10.1038/nature13164 (DOI)000333402000038 ()
Available from: 2014-05-09 Created: 2014-05-09 Last updated: 2020-01-28Bibliographically approved
Seekell, D. A., Lapierre, J.-F., Pace, M. L., Gudasz, C., Sobek, S. & Tranvik, L. J. (2014). Regional-scale variation of dissolved organic carbon concentrations in Swedish lakes. Limnology and Oceanography, 59(5), 1612-1620
Open this publication in new window or tab >>Regional-scale variation of dissolved organic carbon concentrations in Swedish lakes
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2014 (English)In: Limnology and Oceanography, ISSN 0024-3590, E-ISSN 1939-5590, Vol. 59, no 5, p. 1612-1620Article in journal (Refereed) Published
Abstract [en]

We assessed spatial variability in dissolved organic carbon (DOC) concentrations measured in nearly 2000 Swedish lakes. Inter-lake variance peaked at two different scales, representing within-region and between-region variability. The variation between regions was greater than the variation among lakes within regions. We tested relationships between DOC and runoff, drainage ratio, and altitude for spatial heterogeneity using geographically weighted regression. Relationships varied geographically, but cluster analysis delineated two contiguous regions of similar relationships. Altitude had a significant inverse relationship with DOC in the highlands, and drainage ratio had a significant positive relationship with DOC in the lowlands. These heterogeneous relationships explained regional patterns in DOC concentrations. We conclude that regions, rather than individual lakes, are a key, emergent scale of spatial variability for DOC concentrations. This scale of variability reflects the intersection of environmental gradients (e.g., altitude) with spatially heterogeneous relationships (e.g., DOC–drainage ratio relationship). Regional-scale structure in limnological patterns indicates that individual lakes are not independent from one another, but are emergent groups where DOC concentrations are a function of similar environmental patterns and processes.

National Category
Oceanography, Hydrology and Water Resources
Identifiers
urn:nbn:se:uu:diva-230406 (URN)10.4319/lo.2014.59.5.1612 (DOI)000345462100013 ()
Available from: 2014-08-25 Created: 2014-08-25 Last updated: 2020-01-28Bibliographically approved
Santoro, A. L., Bastviken, D., Gudasz, C., Tranvik, L. & Enrich-Prast, A. (2013). Dark Carbon Fixation: An Important Process in Lake Sediments. PLOS ONE, 8(6), e65813
Open this publication in new window or tab >>Dark Carbon Fixation: An Important Process in Lake Sediments
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2013 (English)In: PLOS ONE, E-ISSN 1932-6203, Vol. 8, no 6, p. e65813-Article in journal (Refereed) Published
Abstract [en]

Close to redox boundaries, dark carbon fixation by chemoautotrophic bacteria may be a large contributor to overall carbon fixation. Still, little is known about the relative importance of this process in lake systems, in spite the potentially high chemoautotrophic potential of lake sediments. We compared rates of dark carbon fixation, bacterial production and oxygen consumption in sediments from four Swedish boreal and seven tropical Brazilian lakes. Rates were highly variable and dark carbon fixation amounted up to 80% of the total heterotrophic bacterial production. The results indicate that non-photosynthetic carbon fixation can represent a substantial contribution to bacterial biomass production, especially in sediments with low organic matter content.

National Category
Natural Sciences
Identifiers
urn:nbn:se:uu:diva-206468 (URN)10.1371/journal.pone.0065813 (DOI)000320755400067 ()
Available from: 2013-09-01 Created: 2013-08-30 Last updated: 2021-06-14Bibliographically approved
Projects
Understanding and modeling biome-scale nonlinearities in aquatic carbon burial [2012-06650_VR]; Uppsala University
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-4949-9792

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