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Jansson, Mats
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Publications (10 of 80) Show all publications
Jäger, C. G., Vrede, T., Persson, L. & Jansson, M. (2014). Interactions between metazoans, autotrophs, mixotrophs and bacterioplankton in nutrient-depleted high DOC environments: a long-term experiment. Freshwater Biology, 59(8), 1596-1607.
Open this publication in new window or tab >>Interactions between metazoans, autotrophs, mixotrophs and bacterioplankton in nutrient-depleted high DOC environments: a long-term experiment
2014 (English)In: Freshwater Biology, ISSN 0046-5070, E-ISSN 1365-2427, Vol. 59, no 8, 1596-1607 p.Article in journal (Refereed) Published
Abstract [en]

1. Humic lakes with a high external supply of DOC and low input of nutrients can often support a high biomass of metazoan zooplankton. In such lakes, autotrophic algae compete with bacteria for inorganic nutrients, but bacteria support mixotrophic growth. Consequently, planktonic communities are often dominated by mixotrophic flagellates, while obligate autotrophic phytoplankton occurs in low numbers for extended periods.

2. To test the importance of autotrophic phytoplankton and mixotrophic flagellates as food resources for metazoan grazers and, in turn, the feedback effects of grazers on basal food-web interactions, we conducted a long-term experiment where we simulated abiotic resource relationships of humic lakes (high DOC [glucose] and low P input). We examined the population dynamics of Daphnia galeata when inoculated in systems with autotrophic algae only, mixotrophic algae only and a mixture of autotrophic and mixotrophic algae, and how the systems changed after the inoculation of Daphnia. All combinations were run at high-and low-light conditions to analyse the effects of light on food quantity and quality.

3. Daphnia grew to high densities only when mixotrophs were present at high-light conditions and showed no or only weak growth at low-light conditions or with autotrophs as the only food source.

4. Autotrophic algae and bacteria showed a strong competition for nutrients. Autotrophic algae were released from competition for nutrients after Daphnia grazed on bacteria, which led to a probable change of the bacteria community to less edible but less competitive taxa. As a consequence, there was a mutualistic interaction between autotrophs and mixotrophs before Daphnia were introduced which turned into competition after Daphnia inoculation.

5. We suggest that mixotrophic flagellates can be a critical resource for cladocerans and thereby also have a cascading effect on higher trophic levels, and cladocerans, in turn, have important indirect effects on basal planktonic food webs; hence, both might affect whole lake ecosystems.

Keyword
Daphnia, Dinobryon, food quality, indirect effects, Scenedesmus
National Category
Biological Sciences
Identifiers
urn:nbn:se:umu:diva-92262 (URN)10.1111/fwb.12366 (DOI)000339385100003 ()
Available from: 2014-09-15 Created: 2014-08-25 Last updated: 2017-12-05Bibliographically approved
Karlsson, J., Berggren, M., Ask, J., Byström, P., Jonsson, A., Laudon, H. & Jansson, M. (2014). Response to Comment: Terrestrial support of pelagic consumers in unproductive lakes- Uncertainty and potential in assessments using stable isotopes. Limnology and Oceanography, 59(5), 1800-1803.
Open this publication in new window or tab >>Response to Comment: Terrestrial support of pelagic consumers in unproductive lakes- Uncertainty and potential in assessments using stable isotopes
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2014 (English)In: Limnology and Oceanography, ISSN 0024-3590, E-ISSN 1939-5590, Vol. 59, no 5, 1800-1803 p.Article in journal, Editorial material (Refereed) Published
National Category
Environmental Sciences
Identifiers
urn:nbn:se:umu:diva-98410 (URN)10.4319/lo.2014.59.5.1800 (DOI)000345462100027 ()
Available from: 2015-01-22 Created: 2015-01-22 Last updated: 2017-08-31Bibliographically approved
Rodriguez, P., Ask, J., Hein, C. L., Jansson, M. & Karlsson, J. (2013). Benthic organic carbon release stimulates bacterioplankton production in a clear-water subarctic lake. Freshwater Science, 32(1), 176-182.
Open this publication in new window or tab >>Benthic organic carbon release stimulates bacterioplankton production in a clear-water subarctic lake
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2013 (English)In: Freshwater Science, ISSN 2161-9565, Vol. 32, no 1, 176-182 p.Article in journal (Refereed) Published
Abstract [en]

We carried out a set of experiments in a small clear-water lake in northern Sweden during summer 2010 to assess the effect of organic C (OC) released from epipelic algae on pelagic bacterial production (BP). The release rate of OC (dissolved and particulate) from epipelic algae was similar to 45.4 ng C m(-2) h(-1) Bacterioplankton uptake of dissolved OC was P-limited, and pelagic primary production (PP) was colimited by N and P. Pelagic BP (3.2 +/- 6 mu g C L-1 h(-1)) exceeded pelagic PP (0.012 +/- 0.008 mu g C L-1 h(-1)). Pelagic BP was higher in lake water in contact with sediments and the epipelic algae growing on their surface than in water separated from the sediments. Epipelic algae release OC to lake water and potentially stimulate pelagic BP. However, exploitation of benthic OC probably is suboptimal because of nutrient limitation (primarily by inorganic P) of BP.

Place, publisher, year, edition, pages
Society for Freshwater Science, 2013
Keyword
sediment, benthic algae, organic carbon, bacterioplankton production, clear-water lake
National Category
Environmental Sciences Ecology
Identifiers
urn:nbn:se:umu:diva-67031 (URN)10.1899/12-005.1 (DOI)000314670800015 ()
Available from: 2013-03-15 Created: 2013-03-12 Last updated: 2016-05-19Bibliographically approved
Vestergren, J. E., Vincent, A. G., Persson, P., Jansson, M., Ilstedt, U., Giesler, R., . . . Gröbner, G. (2013). Novel Approaches for Identifying Phosphorus Species in Terrestrial and Aquatic Ecosystems with P-31 NMR. Paper presented at 57th Annual Meeting of the Biophysical-Society, FEB 02-06, 2013, Philadelphia, PA. Biophysical Journal, 104(2), 501A-502A.
Open this publication in new window or tab >>Novel Approaches for Identifying Phosphorus Species in Terrestrial and Aquatic Ecosystems with P-31 NMR
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2013 (English)In: Biophysical Journal, ISSN 0006-3495, E-ISSN 1542-0086, Vol. 104, no 2, 501A-502A p.Article in journal, Meeting abstract (Other academic) Published
National Category
Biophysics
Identifiers
urn:nbn:se:umu:diva-68922 (URN)000316074305050 ()
Conference
57th Annual Meeting of the Biophysical-Society, FEB 02-06, 2013, Philadelphia, PA
Available from: 2013-05-02 Created: 2013-04-29 Last updated: 2017-12-06Bibliographically approved
Jansson, M., Berggren, M., Laudon, H. & Jonsson, A. (2012). Bioavailable phosphorus in humic headwater streams in boreal Sweden. Limnology and Oceanography, 57(4), 1161-1170.
Open this publication in new window or tab >>Bioavailable phosphorus in humic headwater streams in boreal Sweden
2012 (English)In: Limnology and Oceanography, ISSN 0024-3590, E-ISSN 1939-5590, Vol. 57, no 4, 1161-1170 p.Article in journal (Refereed) Published
Abstract [en]

Bioavailable phosphorus (BAP) concentrations were determined nine times between April and October 2010 in two humic boreal headwater streams draining forest-and mire-dominated catchments. BAP was analyzed in a bioassay in which natural P-limited bacterioplankton grew with natural P as the sole P source. In both streams, approximately 90% of the BAP occurred as dissolved species (passing a 0.2-mu m filter), consisting partly of low-molecular-weight forms (passing a filter with nominal cutoff at 1 kDa) and partly of high-molecular-weight forms (passing a 0.2-mu m filter but not a 1-kDa filter). Concentrations of total dissolved BAP varied between 1 mu g L-1 and 14 mu g L-1, with the highest values in the middle of the summer. Compared to the forest stream, BAP concentrations were generally higher in the mire stream, where it occasionally amounted to nearly 50% of total P. Molybdate reactive phosphorus overestimated BAP considerably. Most of the BAP was in forms other than free orthophosphate. Temporal BAP variations showed no relationships with dissolved organic carbon (C) or iron but were positively related to air temperature and negatively related to the absorbance ratio (a254 : a365) of organic compounds in the water, indicating connections between terrestrial export of BAP and temperature-dependent terrestrial C metabolism. Concentrations of BAP can relieve stream bacteria from P limitation, and a significant share of BAP exported to streams can reach and be used in downstream lakes.

National Category
Ecology
Identifiers
urn:nbn:se:umu:diva-59734 (URN)10.4319/lo.2012.57.4.1161 (DOI)000307269300021 ()
Available from: 2012-10-18 Created: 2012-09-25 Last updated: 2017-12-07Bibliographically approved
Jansson, M., Karlsson, J. & Jonsson, A. (2012). Carbon dioxide supersaturation promotes primary production in lakes [Letter to the editor]. Ecology Letters, 15(6), 527-532.
Open this publication in new window or tab >>Carbon dioxide supersaturation promotes primary production in lakes
2012 (English)In: Ecology Letters, ISSN 1461-023X, E-ISSN 1461-0248, Vol. 15, no 6, 527-532 p.Article in journal, Letter (Refereed) Published
Abstract [en]

Ecology Letters (2012) Abstract A majority of the worlds lakes are supersaturated with respect to carbon dioxide (CO2). By experimental manipulation of the CO2 concentration in supersaturated boreal lakes, we demonstrate that phytoplankton primary production was up to 10 times higher in supersaturated lake water in comparison with water with CO2 at equilibrium concentrations and that CO2, together with nutrients, explained most of the variation in pelagic primary production and phytoplankton biomass over a wide variety of unproductive lakes. These results suggest that phytoplankton can be co-limited by CO2 and nutrients in unproductive lakes. As import of terrestrial organic carbon and its subsequent microbial mineralisation in lakes is a driving force of CO2-supersaturation our results suggest that lake productivity and carbon cycling may respond to variations in terrestrial organic carbon export, (e.g. caused by land use or climate change) in ways not described before.

Keyword
CO2-supersaturation, lake ecosystems, primary production
National Category
Earth and Related Environmental Sciences Ecology
Identifiers
urn:nbn:se:umu:diva-56202 (URN)10.1111/j.1461-0248.2012.01762.x (DOI)000303666200003 ()
Available from: 2012-06-12 Created: 2012-06-12 Last updated: 2017-12-07Bibliographically approved
Vincent, A. G., Schleucher, J., Gröbner, G., Vestergren, J., Persson, P., Jansson, M. & Giesler, R. (2012). Changes in organic phosphorus composition in boreal forest humus soils: the role of iron and aluminium. Biogeochemistry, 108(1-3), 485-499.
Open this publication in new window or tab >>Changes in organic phosphorus composition in boreal forest humus soils: the role of iron and aluminium
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2012 (English)In: Biogeochemistry, ISSN 0168-2563, E-ISSN 1573-515X, Vol. 108, no 1-3, 485-499 p.Article in journal (Refereed) Published
Abstract [en]

Organic phosphorus (P) is an important component of boreal forest humus soils, and its concentration has been found to be closely related to the concentration of iron (Fe) and aluminium (Al). We used solution and solid state 31P NMR spectroscopy on humus soils to characterize organic P along two groundwater recharge and discharge gradients in Fennoscandian boreal forest, which are also P sorption gradients due to differences in aluminium (Al) and iron (Fe) concentration in the humus. The composition of organic P changed sharply along the gradients. Phosphate diesters and their degradation products, as well as polyphosphates, were proportionally more abundant in low Al and Fe sites, whereas phosphate monoesters such as myo-, scyllo- and unknown inositol phosphates dominated in high Al and Fe soils. The concentration of inositol phosphates, but not that of diesters, was positively related to Al and Fe concentration in the humus soil. Overall, in high Al and Fe sites the composition of organic P seemed to be closely associated with stabilization processes, whereas in low Al and Fe sites it more closely reflected inputs of organic P, given the dominance of diesters which are generally assumed to constitute the bulk of organic P inputs to the soil. These gradients encompass the broad variation in soil properties detected in the wider Fennoscandian boreal forest landscape, as such our findings provide insight into the factors controlling P biogeochemistry in the region but should be of relevance to boreal forests elsewhere.

Place, publisher, year, edition, pages
Springer, 2012
Keyword
Solution 31P NMR spectroscopy, Solid state 31P NMR, Sorption, Groundwater discharge, Groundwater recharge, Betsele
National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:umu:diva-44955 (URN)10.1007/s10533-011-9612-0 (DOI)000300659300031 ()
Available from: 2011-06-15 Created: 2011-06-15 Last updated: 2017-12-11Bibliographically approved
Vestergren, J., Vincent, A. G., Jansson, M., Persson, P., Istedt, U., Gröbner, G., . . . Schleucher, J. (2012). High resolution characterization of organic phosphorus in soil extracts using 2D 1H-31P NMR correlation spectroscopy. Environmental Science and Technology, 46(7), 3950-3956.
Open this publication in new window or tab >>High resolution characterization of organic phosphorus in soil extracts using 2D 1H-31P NMR correlation spectroscopy
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2012 (English)In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 46, no 7, 3950-3956 p.Article in journal (Refereed) Published
Abstract [en]

Organic phosphorus (P) compounds represent a major component of soil P in many soils and are key sources of P for microbes and plants. Solution NMR (nuclear magnetic resonance spectroscopy) is a powerful technique for characterizing organic P species. However, <sup>31</sup>P NMR spectra are often complicated by overlapping peaks, which hampers identification and quantification of the numerous P species present in soils. Overlap is often exacerbated by the presence of paramagnetic metal ions, even if they are in complexes with EDTA following NaOH/EDTA extraction. By removing paramagnetic impurities using a new precipitation protocol, we achieved a dramatic improvement in spectral resolution. Furthermore, the obtained reduction in line widths enabled the use of multi-dimensional NMR methods to resolve overlapping <sup>31</sup>P signals. Using the new protocol on samples from two boreal humus soils with different Fe contents, two-dimensional <sup>1</sup>H-<sup>31</sup>P correlation spectra allowed unambiguous identification of a large number of P species based on their <sup>31</sup>P and <sup>1</sup>H chemical shifts and their characteristic coupling patterns, which would not have been possible using previous protocols. This approach can be used to identify organic P species in samples from both terrestrial and aquatic environments, increasing our understanding of organic P biogeochemistry.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2012
National Category
Environmental Engineering Environmental Sciences related to Agriculture and Land-use
Identifiers
urn:nbn:se:umu:diva-53091 (URN)10.1021/es204016h (DOI)000302850400048 ()22394413 (PubMedID)
Available from: 2012-03-13 Created: 2012-03-13 Last updated: 2017-12-07Bibliographically approved
Ask, J., Karlsson, J. & Jansson, M. (2012). Net ecosystem production in clear-water and brown-water lakes. Global Biogeochemical Cycles, 26, GB1017.
Open this publication in new window or tab >>Net ecosystem production in clear-water and brown-water lakes
2012 (English)In: Global Biogeochemical Cycles, ISSN 0886-6236, E-ISSN 1944-9224, Vol. 26, GB1017- p.Article in journal (Refereed) Published
Abstract [en]

We studied 15 lakes in northern Sweden with respect to primary production and respiration in benthic and pelagic habitats. The lakes were characterized by different concentrations of colored dissolved organic carbon (DOC) of terrestrial origin, forming a gradient ranging from clear-water to brown-water lakes. Primary production decreased and respiration increased on a whole-lake scale along the gradient of increasing DOC. Thus, the lakes became more net heterotrophic, i.e., had lower net ecosystem production (NEP = gross primary production - community respiration), with increasing terrestrial DOC and this change coincided with increasing partial pressure of carbon dioxide (pCO(2)) in the surface waters. The single most important process for the increasing net heterotrophy along the DOC gradient was pelagic respiration of terrestrial organic carbon. In spite of high metabolic activity in the benthic habitat, benthic primary production and benthic respiration decreased simultaneously with increasing DOC, showing that the benthic habitat was in metabolic balance throughout the gradient. Therefore, the net heterotrophic states of the lakes depended on the terrestrial DOC export to lakes and the concomitant respiration of terrestrial organic carbon in the pelagic habitat.

National Category
Oceanography, Hydrology, Water Resources
Identifiers
urn:nbn:se:umu:diva-53875 (URN)10.1029/2010GB003951 (DOI)000301129200001 ()
Available from: 2012-04-05 Created: 2012-04-04 Last updated: 2017-12-07Bibliographically approved
Wenzel, A., Bergström, A.-K., Jansson, M. & Vrede, T. (2012). Poor direct exploitation of terrestrial particulate organic material from peat layers by Daphnia galeata.. Canadian Journal of Fisheries and Aquatic Sciences, 69(11), 1870-1880.
Open this publication in new window or tab >>Poor direct exploitation of terrestrial particulate organic material from peat layers by Daphnia galeata.
2012 (English)In: Canadian Journal of Fisheries and Aquatic Sciences, ISSN 0706-652X, E-ISSN 1205-7533, Vol. 69, no 11, 1870-1880 p.Article in journal (Refereed) Published
Abstract [en]

Terrestrial organic material (t-OM) can subsidize lake food webs indirectly via incorporation of dissolved t-OM by bacteria and subsequent transfer to higher trophic levels or directly through metazoan consumption of particulate t-OM (t-POM). We tested the effects of peat layer t-POM on Daphnia galeata performance. A pure t-POM diet could not sustain survival, growth, and reproduction of D. galeata. Mixtures of heterotrophic bacteria (Pseudomonas sp.) and phytoplankton (Rhodomonas lacustris) gave higher survival, growth, and reproduction than mixtures of t-POM and Rhodomonas. Daphnids performed best when feeding on pure Rhodomonas diets. Quantification of phosphorus (P) and essential biochemicals (i.e., fatty acids) revealed that Rhodomonas had the highest amounts of all these components. Pseudomonas, while rich in P, contained few essential fatty acids, and t-POM had low concentrations of both P and fatty acids. We therefore suggest that the poor food quality of t-POM in our experiment was due to its suboptimal mineral and biochemical composition and that a substantial proportion of high-quality phytoplankton is necessary to sustain zooplankton biomass.

National Category
Ecology
Identifiers
urn:nbn:se:umu:diva-62258 (URN)10.1139/f2012-110 (DOI)
Available from: 2012-12-13 Created: 2012-12-13 Last updated: 2017-12-06Bibliographically approved
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