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Korsman, Tom
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Publications (10 of 11) Show all publications
Hörnberg, G., Staland, H., Nordström, E.-M., Korsman, T. & Segerström, U. (2012). Fire as an important factor for the genesis of boreal Picea abies swamp forests in Fennoscandia. The Holocene, 22(2), 203-214
Open this publication in new window or tab >>Fire as an important factor for the genesis of boreal Picea abies swamp forests in Fennoscandia
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2012 (English)In: The Holocene, ISSN 0959-6836, E-ISSN 1477-0911, Vol. 22, no 2, p. 203-214Article in journal (Refereed) Published
Abstract [en]

The initial establishment of Picea abies in Sweden and Norway on a landscape level, between 3000 and 1000 years ago, was often preceded by recurrent fire and thereafter the influence of fire decreased. However, in some swamp forests, the absence of fire over the last 3500 years has promoted the continuous presence of deciduous trees, i.e. Picea has not established although it has been present regionally for over 3000 years. Our objective was to study long-term vegetation development and fire history in a Picea swamp forest located close (c. 600 m) to a deciduous swamp forest with a documented fire-free history in northernmost Sweden. The study included analyses of charred particles, pollen and ignition residues. Principal component analysis was applied to identify major changes in the pollen spectra. Our results showed that the current Picea swamp forest has developed from a deciduous fen and that fires affected the fen between 6700 and 2300 cal. yr BP. Picea abies established on the fen around 2200 cal. yr BP, following the last local on-site fire. The main factors responsible for the local vegetation development have been: fire (6700 to 2300 cal. yr BP); autogenous processes and climate (2300 to 1000 cal. yr BP); autogenous processes or anthropogenic impact (1000 to 300 cal. yr BP); anthropogenic impact through selective cutting and grazing (300 to 100 cal. yr BP); and autogenous processes and grazing (100 cal. yr BP to present). We conclude that fire facilitated the initial Picea abies establishment. Once established, Picea abies created local conditions that in combination with a colder and wetter climate prevented fire and the establishment of other tree species.

Keywords
charred particles, fire history, loss-on-ignition, pollen, succession
National Category
Ecology
Identifiers
urn:nbn:se:umu:diva-52200 (URN)10.1177/0959683611414936 (DOI)000298746900007 ()
Available from: 2012-02-13 Created: 2012-02-13 Last updated: 2018-06-08Bibliographically approved
Åhlén, E., Byström, P., Korsman, T., Persson, L. & Reinikainen, M. (2011). Relationships between planktivore community capacity (PCC) and cladoceran microfossils in northern Swedish lakes. Fundamental and Applied Limnology, 178(4), 315-324
Open this publication in new window or tab >>Relationships between planktivore community capacity (PCC) and cladoceran microfossils in northern Swedish lakes
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2011 (English)In: Fundamental and Applied Limnology, ISSN 1863-9135, Vol. 178, no 4, p. 315-324Article in journal (Refereed) Published
Abstract [en]

Planktivorous fish are known to affect the zooplankton community both in terms of species composition and species specific morphological traits. Remains of cladocerans are deposited as microfossils in lake sediments, and the microfossil assembly hence reflects the historical impact of the planktivore community in the lake. The microfossils of cladocerans can therefore be used to reconstruct historical changes in the planktivore fish community in lakes. Catch per unit effort in numbers (CPUEn) and weight (CPUEw) have previously been used as proxies for planktivory. Although these standard measurements are useful in lakes dominated by obligate planktivorous fish, they have limits in their predictive power, particularly in lakes dominated by fish that are not planktivorous throughout their entire lifespan. In this study, we suggest a novel way of estimating the extent of planktivory in lakes, the Planktivore Community Capacity (PCC). PCC takes into account the size and species specific foraging efficiency of fish on zooplankton which gives a more accurate estimate of the intensity of planktivory, especially in lakes dominated by fish that undergo ontogenetic niche shifts from zooplankton to other prey as they grow. Such fish include, for instance, perch (Perca fluviatilis) and Arctic char (Salvelinus alpinus). To analyze the relationship between surface sediment cladoceran remains and planktivory intensity, 39 lakes were sampled regarding the fish community and microfossil assembly. We focused on Bosmina, which is a dominant zooplankton genus in the study area. Bosmina is well preserved in the sediment, and also known to exhibit changes in density and morphology depending on the planktivore predation pressure. We analyzed both the density of two Bosmina species in the sediment and morphological traits in relation to estimates of planktivory intensities. Among the variables measured, morphological traits and relationship between Bosmina longispina and Bosmina longirostris were highly correlated to PCC. PCC had a higher explanatory power than both CPUEn and CPUEw for observed patterns in microfossil characteristics in lakes. We suggest that estimates of Planktivore Community Capacity (PCC) is a powerful approach for reconstructing historical changes in planktivory in lakes.

Place, publisher, year, edition, pages
Stuttgart: E. Schweizerbart, 2011
Keywords
planktivory, foraging efficiency, cladoceran remains, Bosmina, planktivore community capacity
National Category
Biological Sciences Fish and Aquacultural Science
Identifiers
urn:nbn:se:umu:diva-52205 (URN)10.1127/1863-9135/2011/0178-0315 (DOI)000289077700005 ()
Available from: 2012-02-13 Created: 2012-02-13 Last updated: 2018-06-08Bibliographically approved
Rosén, P., Bindler, R., Korsman, T., Mighall, T. & Bishop, K. (2011). The complementary power of pH and lake-water organic carbon reconstructions for discerning the influences on surface waters across decadal to millennial time scales. Biogeosciences, 8, 2717-2727
Open this publication in new window or tab >>The complementary power of pH and lake-water organic carbon reconstructions for discerning the influences on surface waters across decadal to millennial time scales
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2011 (English)In: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 8, p. 2717-2727Article in journal (Refereed) Published
Abstract [en]

Lysevatten, a lake in southwest Sweden, has experienced both acidification and recent changes in the amount of lake-water organic carbon (TOC), both causing concern across Europe and North America. A range of paleolimnological tools – diatom-inferred pH, inferred lake-water TOC from visible-near-infrared spectroscopy (VNIRS), multielement geochemistry and pollen analysis, combined with geochemical modeling were used to reconstruct the lake’s chemistry and surroundings back to the most recent deglaciation 12 500 years ago. The results reveal that the recent anthropogenic impacts are similar in magnitude to the longterm variation driven by natural catchment changes and early agricultural land use occurring over centuries and millennia. The combined reconstruction of both lake-water TOC and lithogenic element delivery can explain the major changes in lake-water pH and modeled acid neutralizing capacity during the past 12 500 years. The results raise important questions regarding what precisely comprises “reference” conditions (i.e., free from human impacts) as defined in the European Water Framework Directive.

National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:umu:diva-47949 (URN)10.5194/bg-8-2717-2011 (DOI)
Available from: 2011-10-04 Created: 2011-10-04 Last updated: 2018-06-08Bibliographically approved
Erlandsson, M., Bishop, K., Fölster, J., Norberg, M., Korsman, T., Kronnäs, V. & Moldan, F. (2008). A comparison of MAGIC and paleolimnological predictions of preindustrial pH for 55 Swedish lakes.. Environmental Science & Technology, 42(1), 43-8
Open this publication in new window or tab >>A comparison of MAGIC and paleolimnological predictions of preindustrial pH for 55 Swedish lakes.
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2008 (English)In: Environmental Science & Technology, ISSN 0013-936X, Vol. 42, no 1, p. 43-8Article in journal (Refereed) Published
Abstract [en]

Two fundamentally different approaches to define reference conditions for acidification assessments are hydrogeochemical modeling and paleolimnological reconstructions. Both methods have been applied to calculate the preindustrial chemistry for 55 Swedish lakes in two independent studies. This paper investigates whether these methods give similar reconstructions of the preindustrial pH for these lakes. Special focus has been attached to the importance of total organic carbon concentrations and CO2 partial pressure (pCO(2)) in the conversion from ANC to pH in the hydrogeochemical modeling. With a uniform pCO(2) value for all the lakes of 0.63 matm, the mean absolute difference between pH from the hydrogeochernical model and the paleolimnological pH was +0.23 units (mean absolute difference 0.36 units). If instead a lake specific preindustrial pCO(2) is assumed, equal to contemporary pCO(2), the mean difference in the predicted preindustrial pH between the two methods was reduced to +0.03 units (mean absolute difference 0.22 units). Statistical analyses indicated that with a lake specific pCO(2), the difference between the reconstructions is smaller than 0.13 pH-units at a 95% level of significance. The results of this study build confidence in the reliability of both methods, providing that lake-specific estimates of pCO(2) are used.

Keywords
Carbon/analysis, Carbon Dioxide/analysis, Diatoms, Fresh Water/*chemistry, Geologic Sediments/analysis, Hydrogen-Ion Concentration, Industry, Models; Theoretical, Sweden
Identifiers
urn:nbn:se:umu:diva-11475 (URN)doi:10.1021/es070432a (DOI)18350873 (PubMedID)
Available from: 2009-01-09 Created: 2009-01-09 Last updated: 2018-06-09Bibliographically approved
Bishop, K., Rapp, L., Köhler, S. & Korsman, T. (2008). Testing the steady-state water chemistry model predictions of pre-industrial lake pH with paleolimnological data from northern Sweden.. Sci Total Environ, 407(1), 723-9
Open this publication in new window or tab >>Testing the steady-state water chemistry model predictions of pre-industrial lake pH with paleolimnological data from northern Sweden.
2008 (English)In: Sci Total Environ, ISSN 0048-9697, Vol. 407, no 1, p. 723-9Article in journal (Refereed) Published
Abstract [en]

Criteria are needed for distinguishing naturally acid water from that acidified by air pollution, especially in the organic-rich waters of northern Sweden. The Steady-State Water Chemistry Model (SSWC) was augmented to include organic acidity so that it could predict pre-industrial pH in organic-rich waters. The resulting model predictions of preindustrial ANC and pH were then tested against diatom predictions of pre-industrial pH and alkalinity in 58 lakes from N. Sweden (after alkalinity was converted to ANC using the CBALK method). The SSWC Model's predictions of pre-industrial lake pH in N. Sweden did not correspond well with the diatom predictions, even when accounting for the uncertainty in the diatom model. This was due to the SSWC's sensitivity to short-term fluctuations in contemporary water chemistry. Thus the SSWC Model is not suitable for judging the acidification of individual lakes in areas such as northern Sweden where the degree of chronic acidification is small, or without a good average value of contemporary water chemistry. These results should be considered when assessing the accuracy of critical loads calculated using SSWC.

Identifiers
urn:nbn:se:umu:diva-11339 (URN)doi:10.1016/j.scitotenv.2008.10.007 (DOI)19004472 (PubMedID)
Available from: 2008-12-16 Created: 2008-12-16 Last updated: 2018-06-09Bibliographically approved
Rippey, B., Anderson, N., Renberg, I. & Korsman, T. (2008). The accuracy of methods used to estimate the whole-lake accumulation rate of organic carbon, major cations, phosphorus and heavy metals in sediment. Journal of Paleolimnology, 39, 83-99
Open this publication in new window or tab >>The accuracy of methods used to estimate the whole-lake accumulation rate of organic carbon, major cations, phosphorus and heavy metals in sediment
2008 (English)In: Journal of Paleolimnology, Vol. 39, p. 83-99Article in journal (Refereed) Published
Abstract [en]

The accuracy of three methods used to estimate the whole-lake accumulation rate of chemicals in sediment, the simple mean accumulation rate, regression against water depth and the mean accumulation rate in sedimentation zones, was assessed. The concentrations and accumulation rates of organic carbon, four major cations, phosphorus and four heavy metals in the 1902 to 1988 sediment layer at 43 sites in Kassjon were used and the three methods gave identical results. The accuracy of the simple mean accumulation rate method using 5 or 10 sites was investigated using Monte Carlo simulation and both versions gave accurate results. If the method used the dry sediment accumulation rate at 5 or 10 sites, along with chemical concentration at one central site, then the errors were less than +/- 10% for five of the chemicals and larger for the others (-20 or 20-40%), although the direction of the bias was predictable. If chemical accumulation rate at the central site only was used to estimate the whole-lake value, the bias increased to 25% for the major cations, 50% for the heavy metals and P, and 85% for organic carbon. Having 43 sites in Kassjon meant that the true whole-lake chemical accumulation rate was known and so the accuracy of the methods and their variants could be assessed for the first time. These findings allow the particulars of the simple mean accumulation rate method to be chosen to suit the accuracy needed for a palaeolimnological investigation.

Identifiers
urn:nbn:se:umu:diva-11474 (URN)doi:10.1007/s10933-007-9098-x (DOI)
Available from: 2009-01-09 Created: 2009-01-09 Last updated: 2018-06-09Bibliographically approved
Renberg, I., Bindler, R. & Korsman, T. (2005). Acid rain and acidification of lakes. In: The physical geography of Fennoscandia (pp. 383-390). : Oxford University Press
Open this publication in new window or tab >>Acid rain and acidification of lakes
2005 (English)In: The physical geography of Fennoscandia, Oxford University Press , 2005, p. 383-390Chapter in book (Refereed)
Place, publisher, year, edition, pages
Oxford University Press, 2005
Identifiers
urn:nbn:se:umu:diva-8070 (URN)
Available from: 2008-01-14 Created: 2008-01-14 Last updated: 2018-06-09Bibliographically approved
Rosén, P., Hall, R., Korsman, T. & Renberg, I. (2000). Diatom transfer-functions for quantifying past air temperature, pH and total organic carbon concentration from lakes in northern Sweden. Journal of Paleolimnology, 24(2), 109-123
Open this publication in new window or tab >>Diatom transfer-functions for quantifying past air temperature, pH and total organic carbon concentration from lakes in northern Sweden
2000 (English)In: Journal of Paleolimnology, ISSN 0921-2728, E-ISSN 1573-0417, Vol. 24, no 2, p. 109-123Article in journal (Refereed) Published
Abstract [en]

The relationships between diatoms (Bacillariophyceae) in surface sediments of lakes and summer air temperature, pH and total organic carbon concentration (TOC) were explored along a steep climatic gradient in northern Sweden to provide a tool to infer past climate conditions from sediment cores. The study sites are in an area with low human impact and range from boreal forest to alpine tundra. Canonical correspondence analysis (CCA) constrained to mean July air temperature and pH clearly showed that diatom community composition was different between lakes situated in conifer-, mountain birch- and alpine-vegetation zones. As a consequence, diatoms and multivariate ordination methods can be used to infer past changes in treeline position and dominant forest type. Quantitative inference models were developed to estimate mean July air temperature, pH and TOC from sedimentary diatom assemblages using weighted averaging (WA) and weighted averaging partial least squares (WA-PLS) regression. Relationships between diatoms and mean July air temperature were independent of lake-water pH, TOC, alkalinity and maximum depth. The results demonstrated that diatoms in lake sediments can provide useful and independent quantitative information for estimating past changes in mean July air temperature (R-jack(2) = 0.62, RMSEP = 0.86 degrees C; R-2 and root mean squared error of prediction (RMSEP) based on jack-knifing), pH (R(j)(2)ack = 0.61, RMSEP = 0.30) and TOC (R-jack(2) = 0.49, RMSEP = 1.33 mg l(-1)). The paper focuses mainly on the relationship between diatom community composition and mean July air temperature, but the relationships to pH and TOC are also discussed.

Keywords
diatoms, climate change, temperature, pH, transfer functions, lake sediments, northern Sweden
Identifiers
urn:nbn:se:umu:diva-46293 (URN)10.1023/A:1008128014721 (DOI)000088036400001 ()
Available from: 2011-08-30 Created: 2011-08-30 Last updated: 2018-06-08
Korsman, T. (1993). Acidification trends in Swedish lakes: an assessment of past water chemistry conditions using lake sediments. (Doctoral dissertation). Umeå: Umeå universitet
Open this publication in new window or tab >>Acidification trends in Swedish lakes: an assessment of past water chemistry conditions using lake sediments
1993 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis presents temporal perspectives of lake acidification in Sweden. Sediment records have been used to study timing, trends and causes of acidification, and two different techniques for assessing past lake-water acidity are presented.

A new technique for pH prediction, based on near-infrared (NIR) spectroscopy of surface sediments, is developed. This study shows that there is a pH related fraction of lake sediments that can be recorded by NIR analysis. Relationships between NIR spectra of surface sediment samples and measured lake-water pH values, and between NIR spectra of sediment cores and historical pH values inferred by diatom analysis, are modelled by partial least squares regression. The prediction errors of the models are comparable to those obtained by modelling of diatom and lake-water pH data. By further development NIR spectroscopy can become useful for inferring past pH, as well as several other lake-water parameters, from sediment cores.

Diatom-based predictive models, using multivariate calibration methods, are developed for inferences of lake-water pH, alkalinity and colour. These models are used to provide a regional assessment of recent lake acidification in the provinces of Västerbotten and Norrbotten, northern Sweden. The study shows that a pH decline has occurred in some southeastern lakes, but that most of the lakes have not faced significant changes in lake-water pH, alkalinity and colour. The inferred water chemistiy changes are discussed in relation to atmospheric deposition and land-use.

In a study of eight acid-sensitive Swedish boreal-forest lakes a past-analogue approach is used to test whether contemporary expansion of conifers could cause lake acidification. Water chemistry changes associated with the natural pre-historic colonization and expansion of spruce in Sweden (≈3000 years B.P.), at times of background atmospheric acidity, are inferred to evaluate the acidification ability of spruce per se on surface waters. This study shows that under natural, unpolluted conditions spruce colonization and expansion did not cause lake acidification.

In a synthesis of palaeolimnological acidification research in Sweden a general model for pH- development for acid clear-water lakes in southern Sweden is presented. The pH-development from the last deglaciation to present time can be divided into four different periods; (i) a natural long-term acidification period (12000 B.P. - 2300 B.P., or later), with a gradual decrease in pH resulting from declining fluxes of base cations from catchment soils; (ii) a human induced alkalization period (2300 B.P. - 1900 A.D.), with a pH increase due to human activities in the catchments; (iii) the recent acidification period (about 1900 A.D. - present), when pH decreased towards 4.5 due to acid deposition and possibly ceased land-use; and (iv) the liming period (1970s - present), when pH often increases to values above 7 following lime treatment to counteract acidification. The implications of these past pH changes for the concept of contemporary lake acidification and for liming policy are outlined.

Place, publisher, year, edition, pages
Umeå: Umeå universitet, 1993. p. 15
Keywords
Palaeolimnology, acidification history, alkalization, acid deposition, land-use, lake sediments, near infrared spectroscopy, diatoms, multivariate calibration, Sweden
National Category
Ecology
Identifiers
urn:nbn:se:umu:diva-140821 (URN)91-7174-838-5 (ISBN)
Projects
digitalisering@umu
Available from: 2017-10-19 Created: 2017-10-19 Last updated: 2018-06-09Bibliographically approved
Åhlén, E., Byström, P., Korsman, T., Persson, L. & Reinikainen, M.Planktivore population dynamics affect body size characteristics of Bosmina: evidence from sediment archive and contemporary lake samples.
Open this publication in new window or tab >>Planktivore population dynamics affect body size characteristics of Bosmina: evidence from sediment archive and contemporary lake samples
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(English)Manuscript (preprint) (Other academic)
Abstract [en]

Planktivorous fish affect the species composition, morphology and size of their zooplankton prey species by size selective predation. Microfossils of cladocerans are preserved in the lake sediment and hence cladoceran fossil characteristics may be used to reconstruct historical variation of planktivory in lakes. In lakes dominated by fish that are not obligate planktivores (e.g. perch, Perca fluviatilis), the individual size determines to large extent the type of resources consumed. Therefore the size distribution and density of such fish populations determine overall planktivory impact in these lakes.In a Northern Swedish lake over a 9-year period, we compared the carapace length and mucro length of the cladoceran Bosmina spp. from the contemporary samples with the sediment archive. We estimated the temporal variation in overall planktivory pressure on Bosmina by calculating a population planktivore capacity (PPC) measure on zooplankton using the population density and size structure of the perch population together with size dependent attack rate functions on Bosmina.Our results show that temporal changes in body size characteristics of Bosmina in the contemporary and fossil remains were strongly correlated. Contemporary lake samples and fossil remains of Bosmina showed similar responses in body size characteristics to changes in estimated PPC. Initially, when PPC was low in the lake, both size of carapace and mucro were large. As PPC increased due to strong recruitment of perch during the middle of the study period both carapace and mucro size were small, to increase again towards the end of the study when PPC decreased again. Small perch, mainly young-of-the-year (YOY) perch contribution to PPC was high, more than 80% of to the total PPC in most years. This suggests that the contribution of the smallest size classes of fish to PPC can be high and needs to be taken into account when trying to relate changes in zooplankton community characteristics to variation in planktivore densities.The similar response in body size characteristics of Bosmina in contemporary and sediment samples to changes in planktivory pressure strongly suggests the body size characteristics of Bosmina microfossils, i.e. the carapace and mucro length can be used to reconstruct historical changes in planktivory in lakes.

National Category
Natural Sciences
Research subject
Limnology
Identifiers
urn:nbn:se:umu:diva-53556 (URN)
Available from: 2012-04-02 Created: 2012-04-02 Last updated: 2018-06-08Bibliographically approved
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