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Publications (10 of 110) Show all publications
Vorobyev, S. N., Pokrovsky, O. S., Kolesnichenko, L. G., Manasypov, R. M., Shirokova, L. S., Karlsson, J. & Kirpotin, S. N. (2019). Biogeochemistry of dissolved carbon, major, and trace elements during spring flood periods on the Ob River. Hydrological Processes, 33(11), 1579-1594
Open this publication in new window or tab >>Biogeochemistry of dissolved carbon, major, and trace elements during spring flood periods on the Ob River
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2019 (English)In: Hydrological Processes, ISSN 0885-6087, E-ISSN 1099-1085, Vol. 33, no 11, p. 1579-1594Article in journal (Refereed) Published
Abstract [en]

Detailed knowledge of the flood period of Arctic rivers remains one of the few factors impeding rigorous prediction of the effect of climate change on carbon and related element fluxes from the land to the Arctic Ocean. In order to test the temporal and spatial variability of element concentration in the Ob River (western Siberia) water during flood period and to quantify the contribution of spring flood period to the annual element export, we sampled the main channel year round in 2014-2017 for dissolved C, major, and trace element concentrations. We revealed high stability (approximately <= 10% relative variation) of dissolved C, major, and trace element concentrations in the Ob River during spring flood period over a 1-km section of the river channel and over 3 days continuous monitoring (3-hr frequency). We identified two groups of elements with contrasting relationship to discharge: (a) DIC and soluble elements (Cl, SO4, Li, B, Na, Mg, Ca, P, V, Cr, Mn, As, Rb, Sr, Mo, Ba, W, and U) negatively correlated (p < 0.05) with discharge and exhibited minimal concentrations during spring flood and autumn high flow and (b) DOC and particle-reactive elements (Al, Fe, Ti, Y, Zr, Nb, Cs, REEs, Hf, Tl, Pb, and Th), some nutrients (K), and metalloids (Ge, Sb, and Te), positively correlated (p < 0.05) with discharge and showed the highest concentrations during spring flood. We attribute the decreased concentration of soluble elements with discharge to dilution by groundwater feeding and increased concentration of DOC and particle-reactive metals with discharge to leaching from surface soil, plant litter, and suspended particles. Overall, the present study provides first-order assessment of fluxes of major and trace elements in the middle course of the Ob River, reveals their high temporal and spatial stability, and characterizes the mechanism of river water chemical composition acquisition.

Place, publisher, year, edition, pages
John Wiley & Sons, 2019
Keywords
baseflow, colloids, flood, lakes, metals, organic carbon, riparian zone, rivers, Siberia, underground waters
National Category
Oceanography, Hydrology and Water Resources
Identifiers
urn:nbn:se:umu:diva-159596 (URN)10.1002/hyp.13424 (DOI)000468081600007 ()
Available from: 2019-06-17 Created: 2019-06-17 Last updated: 2019-06-17Bibliographically approved
Vasconcelos, F. R., Diehl, S., Rodríguez, P., Hedström, P., Karlsson, J. & Byström, P. (2019). Bottom-up and top-down effects of browning and warming on shallow lake food webs. Global Change Biology, 25, 504-521
Open this publication in new window or tab >>Bottom-up and top-down effects of browning and warming on shallow lake food webs
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2019 (English)In: Global Change Biology, ISSN 1354-1013, E-ISSN 1365-2486, Vol. 25, p. 504-521Article in journal (Refereed) Published
Abstract [en]

The productivity and trophic structure of aquatic ecosystems is the result of an interplay between bottom-up and top-down forces that operate both within and across the benthic and pelagic compartments of lake food webs. Contemporary and projected climate changes urge the question how this interplay will be affected by increasing inputs of terrestrial derived, dissolved organic matter (‘browning’) and warming. We addressed this issue by exploring how browning and warming affect the behavior of a relatively simple, conceptual model of a shallow lake food web that is compartmentalized into, dynamically coupled, benthic and pelagic components (abiotic resources, primary producers, grazers, and carnivores). We compared model expectations with the results of a factorial manipulation of browning and warming in a replicated, large-scale field experiment. Both the model and the experiment suggest that browning affects the food web from the bottom-up by reducing light supply to the benthic habitat and increasing nutrient supply to the pelagic habitat, with concomitant decreases of benthic and increases of pelagic primary and secondary production. The model also predicts that warming effects should primarily operate via relaxed top-down control by top consumers in the more productive of the two habitats. The latter was only partially supported by the experimental data, possibly because the model still lacks one or two important trophic links, such as the one from pelagic producers to benthic deposit feeders. We propose that our coupled benthic-pelagic food web model provides a useful conceptual starting point for future theoretical and empirical studies of the impacts of environmental changes on shallow lakes.

Place, publisher, year, edition, pages
John Wiley & Sons, 2019
Keywords
benthic and pelagic habitats, bottom-up and top-down control, browning, food webs, light and nutrients, shallow lake, top predator, warming
National Category
Ecology Environmental Sciences
Identifiers
urn:nbn:se:umu:diva-133326 (URN)10.1111/gcb.14521 (DOI)000456028900011 ()30430702 (PubMedID)
Funder
Knut and Alice Wallenberg FoundationSwedish Research Council, 621-2011-3908Swedish Research Council, 621-2014-5238Ecosystem dynamics in the Baltic Sea in a changing climate perspective - ECOCHANGEThe Kempe Foundations
Note

Originally included in thesis in manuscript form.

Available from: 2017-04-05 Created: 2017-04-05 Last updated: 2019-03-26Bibliographically approved
Klaus, M., Seekell, D. A., Lidberg, W. & Karlsson, J. (2019). Evaluations of Climate and Land Management Effects on Lake Carbon Cycling Need to Account Temporal Variability in CO2 Concentration. Global Biogeochemical Cycles, 33(3), 243-265
Open this publication in new window or tab >>Evaluations of Climate and Land Management Effects on Lake Carbon Cycling Need to Account Temporal Variability in CO2 Concentration
2019 (English)In: Global Biogeochemical Cycles, ISSN 0886-6236, E-ISSN 1944-9224, Vol. 33, no 3, p. 243-265Article in journal (Refereed) Published
Abstract [en]

Carbon dioxide (CO2) concentrations in lakes vary strongly over time. This variability is rarely captured by environmental monitoring but is crucial for accurately assessing the magnitude of lake CO2 emissions. However, it is unknown to what extent temporal variability needs to be captured to understand important drivers of lake carbon cycling such as climate and land management. We used environmental monitoring data of Swedish forest lakes collected in autumn (n = 439) and throughout the whole open water season (n = 22) from a wet and a dry year to assess temporal variability in effects of climate and forestry on CO2 concentrations across lakes. Effects differed depending on the season and year sampled. According to cross-lake comparisons based on autumn data, CO2 concentrations increased with annual mean air temperature (dry year) or catchment forest productivity (wet year) but were not related to colored dissolved organic matter concentrations. In contrast, open water-season averaged CO2 concentrations were similar across temperature and productivity gradients but increased with colored dissolved organic matter. These contradictions resulted from scale mismatches in input data, lead to weak explanatory power (R-2 = 9-32%), and were consistent across published data from 79 temperate, boreal, and arctic lakes. In a global survey of 144 published studies, we identified a trade-off between temporal and spatial coverage of CO2 sampling. This trade-off clearly determines which conclusions are drawn from landscape-scale CO(2 )assessments. Accurate evaluations of the effects of climate and land management require spatially and temporally representative data that can be provided by emerging sensor technologies and forms of collaborative sampling.

Place, publisher, year, edition, pages
American Geophysical Union (AGU), 2019
Keywords
carbon cycling, lake, seasonality, sampling, greenhouse gas, structural equation modeling
National Category
Climate Research
Identifiers
urn:nbn:se:umu:diva-158600 (URN)10.1029/2018GB005979 (DOI)000464651600002 ()
Available from: 2019-05-23 Created: 2019-05-23 Last updated: 2019-05-23Bibliographically approved
Lupon, A., Denfeld, B. A., Laudon, H., Leach, J., Karlsson, J. & Sponseller, R. A. (2019). Groundwater inflows control patterns and sources of greenhouse gas emissions from streams. Limnology and Oceanography, 64(4), 1545-1557
Open this publication in new window or tab >>Groundwater inflows control patterns and sources of greenhouse gas emissions from streams
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2019 (English)In: Limnology and Oceanography, ISSN 0024-3590, E-ISSN 1939-5590, Vol. 64, no 4, p. 1545-1557Article in journal (Refereed) Published
Abstract [en]

Headwater streams can be important sources of carbon dioxide (CO2) and methane (CH4) to the atmosphere. However, the influence of groundwater-stream connectivity on the patterns and sources of carbon (C) gas evasion is still poorly understood. We explored these connections in the boreal landscape through a detailed study of a 1.4 km lake outlet stream that is hydrologically fed by multiple topographically driven groundwater input zones. We measured stream and groundwater dissolved organic C (DOC), CO2, and CH4 concentrations every 50 m biweekly during the ice-free period and estimated in-stream C gas production through a mass balance model and independent estimates of aquatic metabolism. The spatial pattern of C gas concentrations was consistent over time, with peaks of both CH4 and CO2 concentrations occurring after each groundwater input zone. Moreover, lateral C gas inputs from riparian soils were the major source of CO2 and CH4 to the stream. DOC mineralization and CH4 oxidation within the stream accounted for 17-51% of stream CO2 emissions, and this contribution was the greatest during relatively higher flows. Overall, our results illustrate how the nature and arrangement of groundwater flowpaths can organize patterns of stream C concentrations, transformations, and emissions by acting as a direct source of gases and by supplying organic substrates that fuel aquatic metabolism. Hence, refined assessments of how catchment structure influences the timing and magnitude of groundwater-stream connections are crucial for mechanistically understanding and scaling C evasion rates from headwaters.

National Category
Oceanography, Hydrology and Water Resources
Identifiers
urn:nbn:se:umu:diva-161831 (URN)10.1002/lno.11134 (DOI)000474301200009 ()
Available from: 2019-08-12 Created: 2019-08-12 Last updated: 2019-08-12Bibliographically approved
Shirokova, L. S., Chupakov, A. V., Zabelina, S. A., Neverova, N. V., Payandi-Rolland, D., Causserand, C., . . . Pokrovsky, O. S. (2019). Humic surface waters of frozen peat bogs (permafrost zone) are highly resistant to bio- and photodegradation. Biogeosciences, 16(12), 2511-2526
Open this publication in new window or tab >>Humic surface waters of frozen peat bogs (permafrost zone) are highly resistant to bio- and photodegradation
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2019 (English)In: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 16, no 12, p. 2511-2526Article in journal (Refereed) Published
Abstract [en]

In contrast to the large number of studies on humic waters from permafrost-free regions and oligotrophic waters from permafrost-bearing regions, the bio- and photolability of DOM from the humic surface waters of permafrost-bearing regions has not been thoroughly evaluated. Following standardized protocol, we measured biodegradation (at low, intermediate and high temperatures) and photodegradation (at one intermediate temperature) of DOM in surface waters along the hydrological continuum (depression -> stream -> thermokarst lake -> Pechora River) within a frozen peatland in European Russia. In all systems, within the experimental resolution of 5% to 10 %, there was no bio- or photodegradation of DOM over a 1-month incubation period. It is possible that the main cause of the lack of degradation is the dominance of allochthonous refractory (soil, peat) DOM in all waters studied. However, all surface waters were supersaturated with CO2. Thus, this study suggests that, rather than bio- and photodegradation of DOM in the water column, other factors such as peat pore-water DOM processing and respiration of sediments are the main drivers of elevated pCO(2) and CO2 emission in humic boreal waters of frozen peat bogs.

Place, publisher, year, edition, pages
Nicolaus Copernicus University Press, 2019
National Category
Environmental Sciences Ecology
Identifiers
urn:nbn:se:umu:diva-161711 (URN)10.5194/bg-16-2511-2019 (DOI)000473225700001 ()
Funder
Swedish Research Council, 325-2014-6898
Available from: 2019-08-05 Created: 2019-08-05 Last updated: 2019-08-05Bibliographically approved
Bergström, A.-K. & Karlsson, J. (2019). Light and nutrient control phytoplankton biomass responses to global change in northern lakes. Global Change Biology, 25(6), 2021-2029
Open this publication in new window or tab >>Light and nutrient control phytoplankton biomass responses to global change in northern lakes
2019 (English)In: Global Change Biology, ISSN 1354-1013, E-ISSN 1365-2486, Vol. 25, no 6, p. 2021-2029Article in journal (Refereed) Published
Abstract [en]

Global change affects terrestrial loadings of colored dissolved organic carbon (DOC) and nutrients to northern lakes. Still, little is known about how phytoplankton respond to changes in light and nutrient availability across gradients in lake DOC. In this study, we used results from whole-lake studies in northern Sweden to show that annual mean phytoplankton biomass expressed unimodal curved relationships across lake DOC gradients, peaking at threshold DOC levels of around 11 mg/L. Whole-lake single nutrient enrichment in selected lakes caused elevated biomass, with most pronounced effect at the threshold DOC level. These patterns give support to the suggested dual control by DOC on phytoplankton via nutrient (positively) and light (negatively) availability and imply that the lakes' location along the DOC axis is critical in determining to what extent phytoplankton respond to changes in DOC and/or nutrient loadings. By using data from the large Swedish Lake Monitoring Survey, we further estimated that 80% of northern Swedish lakes are below the DOC threshold, potentially experiencing increased phytoplankton biomass with browning alone, and/or combined with nutrient enrichment. The results support the previous model results on effects of browning and eutrophication on lake phytoplankton, and provide important understanding of how northern lakes may respond to future global changes.

Place, publisher, year, edition, pages
John Wiley & Sons, 2019
Keywords
dissolved organic carbon, nitrogen, phosphorus, phytoplankton, whole-lake nutrient enrichment experiments
National Category
Ecology
Identifiers
urn:nbn:se:umu:diva-159589 (URN)10.1111/gcb.14623 (DOI)000467441900013 ()30897262 (PubMedID)
Available from: 2019-06-18 Created: 2019-06-18 Last updated: 2019-06-18Bibliographically approved
Klaus, M., Geibrink, E., Hotchkiss, E. R. & Karlsson, J. (2019). Listening to air–water gas exchange in running waters [Letter to the editor]. Limnology and Oceanography: Methods, 17(7), 395-414
Open this publication in new window or tab >>Listening to air–water gas exchange in running waters
2019 (English)In: Limnology and Oceanography: Methods, ISSN 1541-5856, E-ISSN 1541-5856, Vol. 17, no 7, p. 395-414Article in journal, Letter (Refereed) Published
Abstract [en]

Air–water gas exchange velocities (k) are critical components of many biogeochemical and ecological process studies in aquatic systems. However, their high spatiotemporal variability is difficult to capture with traditional methods, especially in turbulent flow. Here, we investigate the potential of sound spectral analysis to infer k in running waters, based on the rationale that both turbulence and entrained bubbles drive gas exchange and cause a characteristic sound. We explored the relationship between k and sound spectral properties using laboratory experiments and field observations under a wide range of turbulence and bubble conditions. We estimated k using flux chamber measurements of CO2 exchange and recorded sound above and below the water surface by microphones and hydrophones, respectively. We found a strong influence of turbulence and bubbles on sound pressure levels (SPLs) at octave bands of 31.5 Hz and 1000 Hz, respectively. The difference in SPLs at these bands and background noise bands showed a linear correlation with k both in the laboratory (R2 = 0.93–0.99) and in the field (median R2 = 0.42–0.90). Underwater sound indices outperformed aerial sound indices in general, and indices based on hydraulic parameters in particular, in turbulent and bubbly surface flow. The results highlight the unique potential of acoustic techniques to predict k, isolate mechanisms, and improve the spatiotemporal coverage of k estimates in bubbly flow.

Place, publisher, year, edition, pages
Association for the Sciences of Limnology and Oceanography, 2019
National Category
Geophysics
Identifiers
urn:nbn:se:umu:diva-160885 (URN)10.1002/lom3.10321 (DOI)000475817700002 ()2-s2.0-85067657559 (Scopus ID)
Available from: 2019-06-25 Created: 2019-06-25 Last updated: 2019-08-12Bibliographically approved
Selvam, B. P., Lapierre, J.-F., Soares, A. R. A., Bastviken, D., Karlsson, J. & Berggren, M. (2019). Photo-reactivity of dissolved organic carbon in the freshwater continuum. Aquatic Sciences, 81(4), Article ID UNSP 57.
Open this publication in new window or tab >>Photo-reactivity of dissolved organic carbon in the freshwater continuum
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2019 (English)In: Aquatic Sciences, ISSN 1015-1621, E-ISSN 1420-9055, Vol. 81, no 4, article id UNSP 57Article in journal (Refereed) Published
Abstract [en]

The patterns in dissolved organic carbon (DOC) photo-mineralization along the freshwater continuum from land to sea are poorly known. Specifically, it has not been resolved how the photo-degradation ofDOC into CO2 (PD)depends on the combination of intrinsic properties of DOC and extrinsic variables that affect the photo-reactions. We measured PD per unit of absorbed ultraviolet light energy (PD-E-w) in headwater streams, lakes, intermediate rivers and river mouths in Sweden. Surprisingly, no trend of decreasing PD-E-w was found with decreases in colored DOC. However, there was a relationship between PD-E-w and pH, best described by a quadratic (U-shaped) curve, indicating environmental control of photo-reactivity. Interestingly, the highest values for both of these variables were recorded for river mouths. Moreover, PD-E-w increased with proxy variables for the amount of autochthonous DOC in the water. Thus, changes in pH and autochthonous DOC input along the continuum may sustain high DOC photo-mineralization throughout continental aquatic networks.

Place, publisher, year, edition, pages
SPRINGER BASEL AG, 2019
Keywords
Photo-reactivity, Dissolved organic carbon, Freshwater systems, Colored dissolved organic matter, pH
National Category
Oceanography, Hydrology and Water Resources
Identifiers
urn:nbn:se:umu:diva-161976 (URN)10.1007/s00027-019-0653-0 (DOI)000476490500002 ()
Available from: 2019-08-14 Created: 2019-08-14 Last updated: 2019-08-14Bibliographically approved
Denfeld, B. A., Baulch, H. M., del Giorgio, P. A., Hampton, S. E. & Karlsson, J. (2018). A synthesis of carbon dioxide and methane dynamics during the ice-covered period of northern lakes. Limnology and Oceanography Letters, 3(3), 117-131
Open this publication in new window or tab >>A synthesis of carbon dioxide and methane dynamics during the ice-covered period of northern lakes
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2018 (English)In: Limnology and Oceanography Letters, ISSN 2378-2242, Vol. 3, no 3, p. 117-131Article in journal (Refereed) Published
Abstract [en]

The ice‐covered period on lakes in the northern hemisphere has often been neglected or assumed to have less importance relative to the open water season. However, recent studies challenge this convention, suggesting that the winter period is more dynamic than previously thought. In this review, we synthesize the current understanding of under‐ice carbon dioxide (CO2) and methane (CH4) dynamics, highlighting the annual importance of CO2 and CH4 emissions from lakes at ice‐melt. We compiled data from 25 studies that showed that the ice‐melt period represents 17% and 27% of the annual CO2 and CH4 emissions, respectively. We also found evidence that the magnitude and type of emission (i.e., CO2 and CH4) varies with characteristics of lakes including geographic location, lake morphometry, and physicochemical conditions. The scarcity of winter and spring carbon data from northern lakes represents a major gap in our understanding of annual budgets in these lakes and calls for future research during this key period.

Place, publisher, year, edition, pages
John Wiley & Sons, 2018
National Category
Oceanography, Hydrology and Water Resources Ecology
Identifiers
urn:nbn:se:umu:diva-155161 (URN)10.1002/lol2.10079 (DOI)000456696200009 ()
Note

Special Issue: Carbon cycling in inland waters: Progress and perspectives

Available from: 2019-01-09 Created: 2019-01-09 Last updated: 2019-02-27Bibliographically approved
Bartels, P., Ask, J., Andersson, A., Karlsson, J. & Giesler, R. (2018). Allochthonous Organic Matter Supports Benthic but Not Pelagic Food Webs in Shallow Coastal Ecosystems. Ecosystems (New York. Print), 21(7), 1459-1470
Open this publication in new window or tab >>Allochthonous Organic Matter Supports Benthic but Not Pelagic Food Webs in Shallow Coastal Ecosystems
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2018 (English)In: Ecosystems (New York. Print), ISSN 1432-9840, E-ISSN 1435-0629, Vol. 21, no 7, p. 1459-1470Article in journal (Refereed) Published
Abstract [en]

Rivers transport large amounts of allochthonous organic matter (OM) to the ocean every year, but there are still fundamental gaps in how allochthonous OM is processed in the marine environment. Here, we estimated the relative contribution of allochthonous OM (allochthony) to the biomass of benthic and pelagic consumers in a shallow coastal ecosystem in the northern Baltic Sea. We used deuterium as a tracer of allochthony and assessed both temporal variation (monthly from May to August) and spatial variation (within and outside river plume). We found variability in allochthony in space and time and across species, with overall higher values for zoobenthos (26.2 +/- 20.9%) than for zooplankton (0.8 +/- 0.3%). Zooplankton allochthony was highest in May and very low during the other months, likely as a result of high inputs of allochthonous OM during the spring flood that fueled the pelagic food chain for a short period. In contrast, zoobenthos allochthony was only lower in June and remained high during the other months. Allochthony of zoobenthos was generally higher close to the river mouth than outside of the river plume, whereas it did not vary spatially for zooplankton. Last, zoobenthos allochthony was higher in deeper than in shallower areas, indicating that allochthonous OM might be more important when autochthonous resources are limited. Our results suggest that climate change predictions of increasing inputs of allochthonous OM to coastal ecosystems may affect basal energy sources supporting coastal food webs.

Place, publisher, year, edition, pages
Springer, 2018
Keywords
climate change, terrestrial organic carbon, stable isotope analysis, autochthonous production, benthic-pelagic coupling, food webs, Bothnian Sea
National Category
Physical Geography
Identifiers
urn:nbn:se:umu:diva-153548 (URN)10.1007/s10021-018-0233-5 (DOI)000448816300015 ()
Funder
The Kempe FoundationsEcosystem dynamics in the Baltic Sea in a changing climate perspective - ECOCHANGE
Available from: 2018-11-22 Created: 2018-11-22 Last updated: 2018-12-03Bibliographically approved
Projects
Greenhouse gas emission from lakes in northern permafrost areas:quantitative importance and climate impacts [2008-04390_VR]; Umeå UniversityControl of lake productivity: effects of light, terrestrial organic matter and food web structure [2011-03908_VR]; Umeå UniversityEffects of forestry on greenhouse gas emissions from boreal inland waters [2012-1461_Formas]; Umeå UniversitySvenskt deltagande i JPI Climate Arctic and Boreal system.Projekt nr. 70765 [2014-06898_VR]; Umeå UniversityThe invisible carbon-an early indicator of ecosystem change! [2014-970_Formas]; Umeå UniversityMonitoring and management of Arctic lakes in a changing climate [2015-723_Formas]; Umeå UniversityClimate impact on sources and sinks of greenhouse gases in high-latitude lakes [2016-05275_VR]; Umeå University
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-5730-0694

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