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Karlsson, Jan
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Publications (10 of 96) Show all publications
Denfeld, B. A., Klaus, M., Laudon, H., Sponseller, R. A. & Karlsson, J. (2018). Carbon Dioxide and Methane Dynamics in a Small Boreal Lake During Winter and Spring Melt Events. Journal of Geophysical Research - Biogeosciences, 123(8), 2527-2540
Open this publication in new window or tab >>Carbon Dioxide and Methane Dynamics in a Small Boreal Lake During Winter and Spring Melt Events
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2018 (English)In: Journal of Geophysical Research - Biogeosciences, ISSN 2169-8953, E-ISSN 2169-8961, Vol. 123, no 8, p. 2527-2540Article in journal (Refereed) Published
Abstract [en]

In seasonally ice‐covered lakes, carbon dioxide (CO2) and methane (CH4) emission at ice‐off can account for a significant fraction of the annual budget. Yet knowledge of the mechanisms controlling below lake‐ice carbon (C) dynamics and subsequent CO2 and CH4 emissions at ice‐off is limited. To understand the control of below ice C dynamics, and C emissions in spring, we measured spatial variation in CO2, CH4, and dissolved inorganic and organic carbon from ice‐on to ice‐off, in a small boreal lake during a winter with sporadic melting events. Winter melt events were associated with decreased surface water DOC in the forest‐dominated basin and increased surface water CH4 in the mire‐dominated basin. At the whole‐lake scale, CH4 accumulated below ice throughout the winter, whereas CO2 accumulation was greatest in early winter. Mass‐balance estimates suggest that, in addition to the CO2 and CH4 accumulated during winter, external inputs of CO2 and CH4 and internal processing during ice‐melt could represent significant sources of C gas emissions during ice‐off. Moreover, internal processing of CO2 and CH4 worked in opposition, with production of CO2 and oxidation of CH4 dominating at ice‐off. These findings have important implications for how small boreal lakes will respond to warmer winters in the future; increased winter melt events will likely increase external inputs below ice and thus alter the extent and timing of CO2 and CH4 emissions to the atmosphere at ice‐off.

Keywords
winter limnology, carbon cycle, carbon dioxide, methane emissions, ice‐covered lake
National Category
Climate Research
Identifiers
urn:nbn:se:umu:diva-152552 (URN)10.1029/2018JG004622 (DOI)000445731100016 ()2-s2.0-85052445907 (Scopus ID)
Available from: 2018-10-11 Created: 2018-10-11 Last updated: 2018-10-12Bibliographically approved
Hamdan, M., Byström, P., Hotchkiss, E. R., Al-Haidarey, M. J., Ask, J. & Karlsson, J. (2018). Carbon dioxide stimulates lake primary production. Scientific Reports, 8, Article ID 10878.
Open this publication in new window or tab >>Carbon dioxide stimulates lake primary production
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2018 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 10878Article in journal (Refereed) Published
Abstract [en]

Gross primary production (GPP) is a fundamental ecosystem process that sequesters carbon dioxide (CO2) and forms the resource base for higher trophic levels. Still, the relative contribution of different controls on GPP at the whole-ecosystem scale is far from resolved. Here we show, by manipulating CO2 concentrations in large-scale experimental pond ecosystems, that CO2 availability is a key driver of whole-ecosystem GPP. This result suggests we need to reformulate past conceptual models describing controls of lake ecosystem productivity and include our findings when developing models used to predict future lake ecosystem responses to environmental change.

Place, publisher, year, edition, pages
Nature Publishing Group, 2018
National Category
Ecology
Identifiers
urn:nbn:se:umu:diva-150361 (URN)10.1038/s41598-018-29166-3 (DOI)000439026000039 ()30022034 (PubMedID)2-s2.0-85050358594 (Scopus ID)
Available from: 2018-08-10 Created: 2018-08-10 Last updated: 2018-08-10Bibliographically approved
Bergström, A.-K., Karlsson, J., Karlsson, D. & Vrede, T. (2018). Contrasting plankton stoichiometry and nutrient regeneration in northern arctic and boreal lakes. Aquatic Sciences, 80(2), Article ID UNSP 24.
Open this publication in new window or tab >>Contrasting plankton stoichiometry and nutrient regeneration in northern arctic and boreal lakes
2018 (English)In: Aquatic Sciences, ISSN 1015-1621, E-ISSN 1420-9055, Vol. 80, no 2, article id UNSP 24Article in journal (Refereed) Published
Abstract [en]

Contrasting carbon: nitrogen: phosphorus (C: N: P) stoichiometry between phytoplankton and zooplankton affect consumer growth and phytoplankton nutrient limitation via nutrient recycling by zooplankton. However, no study has assessed how regional differences in terrestrial loadings of organic matter affect plankton N: P stoichiometry and recycling in systems with low N deposition and N-limited phytoplankton. We address this question by using data from 14 unproductive headwater arctic and boreal lakes. We found that boreal lakes had higher lake water-and seston C, N and P concentrations than arctic lakes, whereas seston C: N, C: P and N: P ratios did not differ among regions. Boreal zooplankton were also richer in N and P relative to C, with lower somatic N: P ratios, compared to arctic lakes. Consequently, the estimated N: P imbalances between seston and zooplankton were negative in arctic lakes, indicating zooplankton feeding on phytoplankton of suboptimal N content, resulting in low consumer driven N: P recycling (medians arctic sub-mid and high altitude lakes: 11 and 13). In boreal lakes, estimated N: P imbalance did not differ from zero, with a seston N: P stoichiometry matching the N: P requirements of zooplankton, which resulted in higher consumer driven N: P recycling (median 18). Our results imply that regional climate induced catchment differences, through enhanced terrestrial nutrient inputs, affect plankton stoichiometry by raising consumer N: P recycling ratio and changing zooplankton from being mainly N-(arctic) to NP co-limited (boreal). Browning of lakes, in regions with low N deposition, may therefore promote large-scale regional changes in plankton nutrient limitation with potential feedbacks on pelagic food webs.

Place, publisher, year, edition, pages
Springer, 2018
Keywords
Carbon, Nitrogen, Nutrient limitation, Phosphorus, Phytoplankton, Zooplankton
National Category
Oceanography, Hydrology and Water Resources Environmental Sciences Ecology
Identifiers
urn:nbn:se:umu:diva-147316 (URN)10.1007/s00027-018-0575-2 (DOI)000429435600001 ()
Available from: 2018-05-25 Created: 2018-05-25 Last updated: 2018-08-17Bibliographically approved
Vasconcelos, R. F., Diehl, S., Rodríguez, P., Karlsson, J. & Byström, P. (2018). Effects of Terrestrial Organic Matter on Aquatic Primary Production as Mediated by Pelagic-Benthic Resource Fluxes. Ecosystems (New York. Print), 21(6), 1255-1268
Open this publication in new window or tab >>Effects of Terrestrial Organic Matter on Aquatic Primary Production as Mediated by Pelagic-Benthic Resource Fluxes
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2018 (English)In: Ecosystems (New York. Print), ISSN 1432-9840, E-ISSN 1435-0629, Vol. 21, no 6, p. 1255-1268Article in journal (Refereed) Published
Abstract [en]

Flows of energy and matter across habitat boundaries can be major determinants of the functioning of recipient ecosystems. It is currently debated whether terrestrial dissolved organic matter (tDOM) is a resource subsidy or a resource subtraction in recipient lakes. We present data from a long-term field experiment in which pelagic phosphorus concentration and whole-ecosystem primary production increased with increasing tDOM input, suggesting that tDOM acted primarily as a direct nutrient subsidy. Piecewise structural equation modeling supports, however, a substantial contribution of a second mechanism: colored tDOM acted also as a resource subtraction by shading benthic algae, preventing them from intercepting nutrients released across the sediment-water interface. Inhibition of benthic algae by colored tDOM thus indirectly promoted pelagic algae and whole-ecosystem primary production. We conclude that cross-ecosystem terrestrial DOM inputs can modify light and nutrient flows between aquatic habitats and alter the relative contributions of benthic and pelagic habitats to total primary production. These results are particularly relevant for shallow northern lakes, which are projected to receive increased tDOM runoff.

Place, publisher, year, edition, pages
Springer, 2018
Keywords
spatial subsidy, allochthonous input, dissolved organic matter, resource competition, nutrients, light, pelagic, benthic, warming, brownification, piecewise SEM
National Category
Ecology Environmental Sciences
Identifiers
urn:nbn:se:umu:diva-152268 (URN)10.1007/s10021-017-0217-x (DOI)000444384400013 ()
Funder
Knut and Alice Wallenberg FoundationThe Kempe FoundationsSwedish Research Council, 621-2011-3908Swedish Research Council, 621-2014-5238
Available from: 2018-10-02 Created: 2018-10-02 Last updated: 2018-10-02Bibliographically approved
Kuhn, M., Lundin, E. J., Giesler, R., Johansson, M. & Karlsson, J. (2018). Emissions from thaw ponds largely offset the carbon sink of northern permafrost wetlands. Scientific Reports, 8, Article ID 9535.
Open this publication in new window or tab >>Emissions from thaw ponds largely offset the carbon sink of northern permafrost wetlands
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2018 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 9535Article in journal (Refereed) Published
Abstract [en]

Northern regions have received considerable attention not only because the effects of climate change are amplified at high latitudes but also because this region holds vast amounts of carbon (C) stored in permafrost. These carbon stocks are vulnerable to warming temperatures and increased permafrost thaw and the breakdown and release of soil C in the form of carbon dioxide (CO2) and methane (CH4). The majority of research has focused on quantifying and upscaling the effects of thaw on CO2 and CH4 emissions from terrestrial systems. However, small ponds formed in permafrost wetlands following thawing have been recognized as hotspots for C emissions. Here, we examined the importance of small ponds for C fluxes in two permafrost wetland ecosystems in northern Sweden. Detailed flux estimates of thaw ponds during the growing season show that ponds emit, on average (±SD), 279 ± 415 and 7 ± 11 mmol C m−2 d−1 of CO2 and CH4, respectively. Importantly, addition of pond emissions to the total C budget of the wetland decreases the C sink by ~39%. Our results emphasize the need for integrated research linking C cycling on land and in water in order to make correct assessments of contemporary C balances.

Place, publisher, year, edition, pages
Nature Publishing Group, 2018
National Category
Environmental Sciences
Identifiers
urn:nbn:se:umu:diva-150775 (URN)10.1038/s41598-018-27770-x (DOI)000436046500049 ()29934641 (PubMedID)
Available from: 2018-08-28 Created: 2018-08-28 Last updated: 2018-08-28Bibliographically approved
Pokrovsky, O. S., Karlsson, J. & Giesler, R. (2018). Freeze-thaw cycles of Arctic thaw ponds remove colloidal metals and generate low-molecular-weight organic matter. Biogeochemistry, 137(3), 321-336
Open this publication in new window or tab >>Freeze-thaw cycles of Arctic thaw ponds remove colloidal metals and generate low-molecular-weight organic matter
2018 (English)In: Biogeochemistry, ISSN 0168-2563, E-ISSN 1573-515X, Vol. 137, no 3, p. 321-336Article in journal (Refereed) Published
Abstract [en]

High-latitude boreal and arctic surface/inland waters contain sizeable reservoirs of dissolved organic matter (DOM) and trace elements (TE), which are subject to seasonal freezing. Specifically, shallow ponds and lakes in the permafrost zone often freeze solid, which can lead to transformations in the colloidal and dissolved fractions of DOM and TE. Here, we present results from experimental freeze-thaw cycles using iron (Fe)- and DOM-rich water from thaw ponds situated in Stordalen and Storflaket palsa mires in northern Sweden. After ten cycles of freezing, 85% of Fe and 25% of dissolved organic carbon (DOC) were removed from solution in circumneutral fen water (pH 6.9) but a much smaller removal of Fe and DOC (< 7%) was found in acidic bog water (pH 3.6). This removal pattern was consistent with initial supersaturation of fen water with respect to Fe hydroxide and a lack of supersaturation with any secondary mineral phase in the bog water. There was a nearly two- to threefold increase in the low-molecular-weight (LMW) fraction of organic carbon (OC) and several TEs caused by the repeated freeze-thaw cycles. Future increases in the freeze-thaw frequency of surface waters with climate warming may remove up to 25% of DOC in circumneutral organic-rich waters. Furthermore, an increase of LMW OC may result in enhanced carbon dioxide losses from aquatic ecosystems since this fraction is potentially more susceptible to biodegradation.

Keywords
Peat, Fen, Bog, Ultrafiltration, Metal, Carbon
National Category
Environmental Sciences
Identifiers
urn:nbn:se:umu:diva-145600 (URN)10.1007/s10533-018-0421-6 (DOI)000425543200004 ()
Funder
Swedish Research Council, 2013-5001
Available from: 2018-03-22 Created: 2018-03-22 Last updated: 2018-06-09Bibliographically approved
Creed, I. F., Bergström, A.-K., Trick, C. G., Grimm, N. B., Hessen, D. O., Karlsson, J., . . . Weyhenmeyer, G. A. (2018). Global change-driven effects on dissolved organic matter composition: Implications for food webs of northern lakes. Global Change Biology, 24(8), 3692-3714
Open this publication in new window or tab >>Global change-driven effects on dissolved organic matter composition: Implications for food webs of northern lakes
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2018 (English)In: Global Change Biology, ISSN 1354-1013, E-ISSN 1365-2486, Vol. 24, no 8, p. 3692-3714Article, review/survey (Refereed) Published
Abstract [en]

Northern ecosystems are experiencing some of the most dramatic impacts of global change on Earth. Rising temperatures, hydrological intensification, changes in atmospheric acid deposition and associated acidification recovery, and changes in vegetative cover are resulting in fundamental changes in terrestrial-aquatic biogeochemical linkages. The effects of global change are readily observed in alterations in the supply of dissolved organic matter (DOM)-the messenger between terrestrial and lake ecosystems-with potentially profound effects on the structure and function of lakes. Northern terrestrial ecosystems contain substantial stores of organic matter and filter or funnel DOM, affecting the timing and magnitude of DOM delivery to surface waters. This terrestrial DOM is processed in streams, rivers, and lakes, ultimately shifting its composition, stoichiometry, and bioavailability. Here, we explore the potential consequences of these global change-driven effects for lake food webs at northern latitudes. Notably, we provide evidence that increased allochthonous DOM supply to lakes is overwhelming increased autochthonous DOM supply that potentially results from earlier ice-out and a longer growing season. Furthermore, we assess the potential implications of this shift for the nutritional quality of autotrophs in terms of their stoichiometry, fatty acid composition, toxin production, and methylmercury concentration, and therefore, contaminant transfer through the food web. We conclude that global change in northern regions leads not only to reduced primary productivity but also to nutritionally poorer lake food webs, with discernible consequences for the trophic web to fish and humans.

Place, publisher, year, edition, pages
John Wiley & Sons, 2018
Keywords
atmospheric change, cyanobacteria, dissolved organic matter, food webs, lake, mercury, northern
National Category
Environmental Sciences
Identifiers
urn:nbn:se:umu:diva-150465 (URN)10.1111/gcb.14129 (DOI)000437284700035 ()29543363 (PubMedID)
Funder
Swedish Research Council, AKB 2010-4675Swedish Research Council, RG 2013-5001
Available from: 2018-08-13 Created: 2018-08-13 Last updated: 2018-08-22Bibliographically approved
Klaus, M., Geibrink, E., Jonsson, A., Bergström, A.-K., Bastviken, D., Laudon, H., . . . Karlsson, J. (2018). Greenhouse gas emissions from boreal inland waters unchanged after forest harvesting. Biogeosciences, 15(18), 5575-5594
Open this publication in new window or tab >>Greenhouse gas emissions from boreal inland waters unchanged after forest harvesting
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2018 (English)In: Biogeosciences, ISSN 1726-4170, Vol. 15, no 18, p. 5575-5594Article in journal (Refereed) Published
Abstract [en]

Forestry practices often result in an increased export of carbon and nitrogen to downstream aquatic systems. Although these losses affect the greenhouse gas (GHG) budget of managed forests, it is unknown if they modify GHG emissions of recipient aquatic systems. To assess this question, air-water fluxes of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) were quantified for humic lakes and their inlet streams in four boreal catchments using a before-after control-impact experiment. Two catchments were treated with forest clear-cuts followed by site preparation (18 % and 44 % of the catchment area). GHG fluxes and hydrological and physicochemical water characteristics were measured at multiple locations in lakes and streams at high temporal resolution throughout the summer season over a 4-year period. Both lakes and streams evaded all GHGs. The treatment did not significantly change GHG fluxes in streams or lakes within 3 years after the treatment, despite significant increases of CO2 and CH4 concentrations in hillslope groundwater. Our results highlight that GHGs leaching from forest clear-cuts may be buffered in the riparian zone-stream continuum, likely acting as effective biogeochemical processors and wind shelters to prevent additional GHG evasion via downstream inland waters. These findings are representative of low productive forests located in relatively flat landscapes where forestry practices cause only a limited initial impact on catchment hydrology and biogeochemistry.

Place, publisher, year, edition, pages
Copernicus Gesellschaft, 2018
National Category
Forest Science
Identifiers
urn:nbn:se:umu:diva-152400 (URN)10.5194/bg-15-5575-2018 (DOI)000445040900002 ()
Funder
Swedish Research Council Formas, 210-2012-1461The Kempe Foundations, SMK-1240EU, European Research Council, 725546
Available from: 2018-10-05 Created: 2018-10-05 Last updated: 2018-10-05Bibliographically approved
Diehl, S., Thomsson, G., Kahlert, M., Guo, J., Karlsson, J. & Liess, A. (2018). Inverse relationship of epilithic algae and pelagic phosphorus in unproductive lakes: Roles of N-2 fixers and light. Freshwater Biology, 63(7), 662-675
Open this publication in new window or tab >>Inverse relationship of epilithic algae and pelagic phosphorus in unproductive lakes: Roles of N-2 fixers and light
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2018 (English)In: Freshwater Biology, ISSN 0046-5070, E-ISSN 1365-2427, Vol. 63, no 7, p. 662-675Article in journal (Refereed) Published
Abstract [en]

Phosphorus (P) often limits the biomass of primary producers in freshwater lakes. However, in unproductive northern lakes, where anthropogenic nitrogen (N) deposition is low, N instead of P can limit primary producers. In addition, light can be limiting to primary producers at high concentrations of coloured dissolved organic matter (cDOM), as cDOM is the major determinant of light penetration in these lakes.

To address resource limitation of epilithic algal biomass, we repeatedly sampled epilithon (periphyton on stony substrata) in 20 lakes covering a large, correlated cDOM and N‐deposition gradient across boreal and subarctic Sweden. Across these lakes, pelagic total N (TN) and total P (TP) were positively correlated, and benthic light supply was negatively correlated, with cDOM. Microscopically determined algal biovolume and epilithic carbon (C), N and P were subsequently regressed against benthic light supply and pelagic TN and TP.

Patterns in epilithic biovolume were driven by N2‐fixing cyanobacteria, which accounted for 2%–90% of total epilithic biovolume. Averaged over the growing season, epilithic algal biovolume, C and N were negatively related to TP and positively to TN, and were highest in the clearest, most phosphorus‐poor lakes, where epilithon was heavily dominated by potentially N2‐fixing cyanobacteria.

A structural equation model supports the hypothesis that cDOM had two counteracting effects on total epilithic algal biovolume: a positive one by providing N to algae that depend on dissolved N for growth, and a negative one by shading N2‐fixing cyanobacteria, with the negative effect being somewhat stronger.

Together, these findings suggest that (1) light and N are the main resources limiting epilithic algal biomass in boreal to subarctic Swedish lakes, (2) epilithic cyanobacteria are more competitive in high‐light and low‐nitrogen environments, where their N2‐fixing ability allows them to reach high biomass, and (3) epilithic N increases with N2 fixer biomass and is—seemingly paradoxically—highest in the most oligotrophic lakes.

Place, publisher, year, edition, pages
John Wiley & Sons, 2018
Keywords
dissolved organic matter, light, nitrogen-fixing cyanobacteria, nutrients, periphyton
National Category
Ecology
Identifiers
urn:nbn:se:umu:diva-150170 (URN)10.1111/fwb.13103 (DOI)000434110200005 ()
Funder
Swedish Research Council, 621-2014-5238Swedish Research Council Formas
Available from: 2018-07-18 Created: 2018-07-18 Last updated: 2018-07-18Bibliographically approved
Ala-aho, P., Soulsby, C., Pokrovsky, O. S., Kirpotin, S. N., Karlsson, J., Serikova, S., . . . Tetzlaff, D. (2018). Permafrost and lakes control river isotope composition across a boreal Arctic transect in the Western Siberian lowlands. Environmental Research Letters, 13(3), =20-=20, Article ID 034028.
Open this publication in new window or tab >>Permafrost and lakes control river isotope composition across a boreal Arctic transect in the Western Siberian lowlands
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2018 (English)In: Environmental Research Letters, ISSN 1748-9326, E-ISSN 1748-9326, Vol. 13, no 3, p. =20-=20, article id 034028Article in journal (Refereed) Published
Abstract [en]

The Western Siberian Lowlands (WSL) store large quantities of organic carbon that will be exposed and mobilized by the thawing of permafrost. The fate of mobilized carbon, however, is not well understood, partly because of inadequate knowledge of hydrological controls in the region which has a vast low-relief surface area, extensive lake and wetland coverage and gradually increasing permafrost influence. We used stable water isotopes to improve our understanding of dominant landscape controls on the hydrology of the WSL. We sampled rivers along a 1700 km South-North transect from permafrost-free to continuous permafrost repeatedly over three years, and derived isotope proxies for catchment hydrological responsiveness and connectivity. We found correlations between the isotope proxies and catchment characteristics, suggesting that lakes and wetlands are intimately connected to rivers, and that permafrost increases the responsiveness of the catchment to rainfall and snowmelt events, reducing catchment mean transit times. Our work provides rare isotope-based field evidence that permafrost and lakes/wetlands influence hydrological pathways across a wide range of spatial scales (10-105 km2) and permafrost coverage (0%-70%). This has important implications, because both permafrost extent and lake/wetland coverage are affected by permafrost thaw in the changing climate. Changes in these hydrological landscape controls are likely to alter carbon export and emission via inland waters, which may be of global significance.

Keywords
stable water isotopes, Western Siberia Lowlands, mean transit time, hydrological connectivity, permafrost
National Category
Oceanography, Hydrology and Water Resources
Identifiers
urn:nbn:se:umu:diva-146150 (URN)10.1088/1748-9326/aaa4fe (DOI)000426518100004 ()
Available from: 2018-05-03 Created: 2018-05-03 Last updated: 2018-08-20Bibliographically approved
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