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Giesler, Reiner
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Publications (10 of 61) Show all publications
Wardle, D. A., Bellingham, P. J., Kardol, P., Giesler, R. & Tanner, E. V. (2015). Coordination of aboveground and belowground responses to local-scale soil fertility differences between two contrasting Jamaican rain forest types. Oikos, 124(3), 285-297
Open this publication in new window or tab >>Coordination of aboveground and belowground responses to local-scale soil fertility differences between two contrasting Jamaican rain forest types
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2015 (English)In: Oikos, ISSN 0030-1299, E-ISSN 1600-0706, Vol. 124, no 3, p. 285-297Article in journal (Refereed) Published
Abstract [en]

There is growing interest in understanding how declining soil fertility in the prolonged absence of major disturbance drives ecological processes, or ecosystem retrogression'. However, there are few well characterized study systems for exploring this phenomenon in the tropics, despite tropics occupying over 40% of the Earth's terrestrial surface. We studied two types of montane rain forest in the Blue Mountains of Jamaica that represent distinct stages in ecosystem development, i.e. an earlier stage with shallow organic matter and a late stage with deep organic matter (hereafter mull' and mor' stages). We characterized responses of soil fertility and plant, soil microbial and nematode communities to the transition from mull to mor and whether these responses were coupled. For soil abiotic properties, we found this transition led to lower amounts of both nitrogen (N) and phosphorus (P) and an enhanced N to P ratio. This led to shorter-statured and less diverse forest, and convergence of tree species composition among plots. At the whole community (but not individual species) level foliar and litter N and P diminished from mull to mor, while foliar N to P and resorption efficiency of P relative to N increased, indicating increasing P relative to N limitation. We also found impairment of soil microbes (but not nematodes) and an increasing role of fungi relative to bacteria during the transition. Our results show that retrogression phenomena involving increasing nutrient (notably P) limitation can be important drivers in tropical systems, and are likely to involve aboveground-belowground feedbacks whereby plants produce litter of diminishing quality, impairing soil microbial processes and thus reducing the supply of nutrients from the soil for plant growth. Such feedbacks between plants and the soil, mediated by plant litter and organic matter quality, may serve as major though often overlooked drivers of long term environmental change.

Place, publisher, year, edition, pages
Wiley-Blackwell, 2015
National Category
Ecology
Identifiers
urn:nbn:se:umu:diva-101595 (URN)10.1111/oik.01584 (DOI)000350462700005 ()
Available from: 2015-04-14 Created: 2015-04-07 Last updated: 2017-12-04Bibliographically approved
Thompson, M. S., Giesler, R., Karlsson, J. & Klaminder, J. (2015). Size and characteristics of the DOC pool in near-surface subarctic mire permafrost as a potential source for nearby freshwaters. Arctic, Antarctic and Alpine research, 47(1), 49-58
Open this publication in new window or tab >>Size and characteristics of the DOC pool in near-surface subarctic mire permafrost as a potential source for nearby freshwaters
2015 (English)In: Arctic, Antarctic and Alpine research, ISSN 1523-0430, E-ISSN 1938-4246, Vol. 47, no 1, p. 49-58Article in journal (Refereed) Published
Abstract [en]

Subarctic peatlands are rich sources of organic carbon for freshwater ecosystems. Where those peatlands are underlain by permafrost, permafrost thaw may cause an initial release of bioavailable dissolved organic carbon (DOC) to surrounding freshwaters. In this study, we measured icebound and potentially leachable (extracted) DOC quantities and indices of DOC quality in active layer and permafrost layers from two subarctic peat mires, Stord-alen and Storflaket. Most of the permafrost layers did not contain more organic matter or exportable DOC (as g kg(-1) dry soil) than the overlying active layer, and there was no difference in aromaticity, molecular weight, or the ratio between labile and recalcitrant DOC extracted from the permafrost and active layer. However, DOC held in segregated ice of the near-surface permafrost had relatively low aromaticity compared to extracted DOC from the same depth. Total icebound and potentially leachable DOC in the Stordalen mire permafrost that is predicted to experience active layer deepening during each of the next 50 years corresponded to about 0.1% of the current annual aquatic export of DOC from the mire. We conclude that the pool of potentially leachable DOC currently stored in permafrost layers is small. We also highlight differences in permafrost organic material between the two studied mire systems, which has an effect on the pool and properties of leachable DOC that is potentially available for export during thaw. Moreover, the geomorphological form of permafrost thaw will influence future hydrological connectedness and DOC production, in turn determining future DOC export from the mires.

National Category
Environmental Sciences Ecology Physical Geography
Identifiers
urn:nbn:se:umu:diva-101615 (URN)10.1657/AAAR0014-010 (DOI)000350219000005 ()
Available from: 2015-04-10 Created: 2015-04-07 Last updated: 2018-01-11Bibliographically approved
Vincent, A. G., Sundqvist, M. K., Wardle, D. A. & Giesler, R. (2014). Bioavailable Soil Phosphorus Decreases with Increasing Elevation in a Subarctic Tundra Landscape. PLoS ONE, 9(3), e92942
Open this publication in new window or tab >>Bioavailable Soil Phosphorus Decreases with Increasing Elevation in a Subarctic Tundra Landscape
2014 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 3, p. e92942-Article in journal (Refereed) Published
Abstract [en]

Phosphorus (P) is an important macronutrient in arctic and subarctic tundra and its bioavailability is regulated by the mineralization of organic P. Temperature is likely to be an important control on P bioavailability, although effects may differ across contrasting plant communities with different soil properties. We used an elevational gradient in northern Sweden that included both heath and meadow vegetation types at all elevations to study the effects of temperature, soil P sorption capacity and oxalate-extractable aluminium (Al-ox) and iron (Fe-ox) on the concentration of different soil P fractions. We hypothesized that the concentration of labile P fractions would decrease with increasing elevation (and thus declining temperature), but would be lower in meadow than in heath, given that N to P ratios in meadow foliage are higher. As expected, labile P in the form of Resin-P declined sharply with elevation for both vegetation types. Meadow soils did not have lower concentrations of Resin-P than heath soils, but they did have 2-fold and 1.5-fold higher concentrations of NaOH-extractable organic P and Residual P, respectively. Further, meadow soils had 3-fold higher concentrations of Al-ox + Feox and a 20% higher P sorption index than did heath soils. Additionally, Resin-P expressed as a proportion of total soil P for the meadow was on average half that in the heath. Declining Resin-P concentrations with elevation were best explained by an associated 2.5-3.0 degrees C decline in temperature. In contrast, the lower P availability in meadow relative to heath soils may be associated with impaired organic P mineralization, as indicated by a higher accumulation of organic P and P sorption capacity. Our results indicate that predicted temperature increases in the arctic over the next century may influence P availability and biogeochemistry, with consequences for key ecosystem processes limited by P, such as primary productivity.

Place, publisher, year, edition, pages
PLOS one, 2014
National Category
Biological Sciences
Identifiers
urn:nbn:se:umu:diva-88398 (URN)10.1371/journal.pone.0092942 (DOI)000333677500058 ()
Available from: 2014-05-05 Created: 2014-05-05 Last updated: 2017-12-05Bibliographically approved
Giesler, R., Lyon, S. W., Morth, C.-M., Karlsson, J., Karlsson, E. M., Jantze, E. J., . . . Humborg, C. (2014). Catchment-scale dissolved carbon concentrations and export estimates across six subarctic streams in northern Sweden. Biogeosciences, 11(2), 525-537
Open this publication in new window or tab >>Catchment-scale dissolved carbon concentrations and export estimates across six subarctic streams in northern Sweden
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2014 (English)In: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 11, no 2, p. 525-537Article in journal (Refereed) Published
Abstract [en]

Climatic change is currently enhancing permafrost thawing and the flow of water through the landscape in subarctic and arctic catchments, with major consequences for the carbon export to aquatic ecosystems. We studied stream water carbon export in several tundra-dominated catchments in northern Sweden. There were clear seasonal differences in both dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) concentrations. The highest DOC concentrations occurred during the spring freshet while the highest DIC concentrations were always observed during winter baseflow conditions for the six catchments considered in this study. Long-term trends for the period 1982 to 2010 for one of the streams showed that DIC concentrations has increased by 9% during the 28 yr of measurement while no clear trend was found for DOC. Similar increasing trends were also found for conductivity, Ca and Mg. When trends were discretized into individual months, we found a significant linear increase in DIC concentrations with time for September, November and December. In these subarctic catchments, the annual mass of C exported as DIC was in the same order of magnitude as DOC; the average proportion of DIC to the total dissolved C exported was 61% for the six streams. Furthermore, there was a direct relationship between total runoff and annual dissolved carbon fluxes for these six catchments. These relationships were more prevalent for annual DIC exports than annual DOC exports in this region. Our results also highlight that both DOC and DIC can be important in high-latitude ecosystems. This is particularly relevant in environments where thawing permafrost and changes to subsurface ice due to global warming can influence stream water fluxes of C. The large proportion of stream water DIC flux also has implications on regional C budgets and needs to be considered in order to understand climate-induced feedback mechanisms across the landscape.

National Category
Ecology
Identifiers
urn:nbn:se:umu:diva-93300 (URN)10.5194/bg-11-525-2014 (DOI)000331260900022 ()
Funder
Swedish Research Council, 70384101Swedish Research Council Formas, 214-2008-202
Available from: 2014-09-16 Created: 2014-09-16 Last updated: 2017-12-05Bibliographically approved
Sundqvist, M. K., Wardle, D. A., Vincent, A. & Giesler, R. (2014). Contrasting nitrogen and phosphorus dynamics across an elevational gradient for subarctic tundra heath and meadow vegetation. Plant and Soil, 383(1-2), 387-399
Open this publication in new window or tab >>Contrasting nitrogen and phosphorus dynamics across an elevational gradient for subarctic tundra heath and meadow vegetation
2014 (English)In: Plant and Soil, ISSN 0032-079X, E-ISSN 1573-5036, Vol. 383, no 1-2, p. 387-399Article in journal (Refereed) Published
Abstract [en]

This study explores soil nutrient cycling processes and microbial properties for two contrasting vegetation types along an elevational gradient in subarctic tundra to improve our understanding of how temperature influences nutrient availability in an ecosystem predicted to be sensitive to global warming. We measured total amino acid (Amino-N), mineral nitrogen (N) and phosphorus (P) concentrations, in situ net N and P mineralization, net Amino-N consumption, and microbial biomass C, N and P in both heath and meadow soils across an elevational gradient near Abisko, Sweden. For the meadow, NH4 (+) concentrations and net N mineralization were highest at high elevations and microbial properties showed variable responses; these variables were largely unresponsive to elevation for the heath. Amino-N concentrations sometimes showed a tendency to increase with elevation and net Amino-N consumption was often unresponsive to elevation. Overall, PO4-P concentrations decreased with elevation and net P immobilization mostly occurred at lower elevations; these effects were strongest for the heath. Our results reveal that elevation-associated changes in temperature can have contrasting effects on the cycling of N and P in subarctic soils, and that the strength and direction of these effects depend strongly on dominant vegetation type.

Place, publisher, year, edition, pages
Springer Netherlands, 2014
Keyword
nutrient availability, mineralization, immobilization, microbial biomass, amino acids, temperature
National Category
Soil Science Agricultural Science
Identifiers
urn:nbn:se:umu:diva-95272 (URN)10.1007/s11104-014-2179-5 (DOI)000342415800028 ()
Available from: 2014-10-31 Created: 2014-10-27 Last updated: 2017-12-05Bibliographically approved
Sundqvist, M. K., Liu, Z., Giesler, R. & Wardle, D. A. (2014). Plant and microbial responses to nitrogen and phosphorus addition across an elevational gradient in subarctic tundra. Ecology, 95(7), 1819-1835
Open this publication in new window or tab >>Plant and microbial responses to nitrogen and phosphorus addition across an elevational gradient in subarctic tundra
2014 (English)In: Ecology, ISSN 0012-9658, E-ISSN 1939-9170, Vol. 95, no 7, p. 1819-1835Article in journal (Refereed) Published
Abstract [en]

Temperature and nutrients are major limiting factors in subarctic tundra. Experimental manipulation of nutrient availability along elevational gradients (and thus temperature) can improve our understanding of ecological responses to climate change. However, no study to date has explored impacts of nutrient addition along a tundra elevational gradient, or across contrasting vegetation types along any elevational gradient. We set up a full factorial nitrogen (N) and phosphorus (P) fertilization experiment in each of two vegetation types (heath and meadow) at 500 m, 800 m, and 1000 m elevation in northern Swedish tundra. We predicted that plant and microbial communities in heath or at lower elevations would be more responsive to N addition while communities in meadow or at higher elevations would be more responsive to P addition, and that fertilizer effects would vary more with elevation for the heath than for the meadow. Although our results provided little support for these predictions, the relationship between nutrient limitation and elevation differed between vegetation types. Most plant and microbial properties were responsive to N and/or P fertilization, but responses often varied with elevation and/or vegetation type. For instance, vegetation density significantly increased with N + P fertilization relative to the other fertilizer treatments, and this increase was greatest at the lowest elevation for the heath but at the highest elevation for the meadow. Arbuscular mycorrhizae decreased with P fertilization at 500 m for the meadow, but with all fertilizer treatments in both vegetation types at 800 m. Fungal to bacterial ratios were enhanced by N + P fertilization for the two highest elevations in the meadow only. Additionally, microbial responses to fertilization were primarily direct rather than indirect via plant responses, pointing to a decoupled response of plant and microbial communities to nutrient addition and elevation. Because our study shows how two community types differ in their responses to fertilization and elevation, and because the temperature range across this gradient is similar to 3 degrees C, our study is informative about how nutrient limitation in tundra may be influenced by temperature shifts that are comparable to those expected under climate change during this century.

Keyword
above- and belowground communities, fertilization experiment, fungal-to-bacterial ratios, global warming, plant functional groups, plant-soil linkages
National Category
Ecology Environmental Sciences
Identifiers
urn:nbn:se:umu:diva-92270 (URN)000339470500012 ()
Available from: 2014-09-09 Created: 2014-08-25 Last updated: 2017-12-05Bibliographically approved
Karlsson, J., Giesler, R., Persson, J. & Lundin, E. (2013). High emission of carbon dioxide and methane during ice thaw in high latitude lakes. Geophysical Research Letters, 40(6), 1123-1127
Open this publication in new window or tab >>High emission of carbon dioxide and methane during ice thaw in high latitude lakes
2013 (English)In: Geophysical Research Letters, ISSN 0094-8276, E-ISSN 1944-8007, Vol. 40, no 6, p. 1123-1127Article in journal (Refereed) Published
Abstract [en]

The winter period is seldom included in the estimates of aquatic-atmospheric carbon exchange. In this study we quantified the flux of carbon dioxide (CO2) and methane (CH4) over 3 years from 12 small subarctic lakes. The lakes accumulated consistent and high amounts of CO2 and CH4 (56–97% as CO2) over the winter, resulting in a high flux during ice thaw. The CO2 flux during ice thaw increased with increasing mean depth of the lakes, while the CH4 flux was high in lakes surrounded by mires. The ice thaw period was quantitatively important to the annual gas balances of the lakes. For nine of the lakes, 11 to 55% of the annual flux occurred during thaw. For three of the lakes with an apparent net annual CO2 uptake, including the thaw period reversed the balance from sink to source. Our results suggest that the ice thaw period is critically important for the emissions of CO2 and CH4 in small lakes.

Place, publisher, year, edition, pages
John Wiley & Sons, 2013
Keyword
lakes, carbon fluxes, winter
National Category
Climate Research Physical Geography
Identifiers
urn:nbn:se:umu:diva-71370 (URN)10.1002/grl.50152 (DOI)000319215700019 ()
Available from: 2013-05-27 Created: 2013-05-27 Last updated: 2018-03-15Bibliographically approved
Lundin, E. J., Giesler, R., Persson, A., Thompson, M. S. & Karlsson, J. (2013). Integrating carbon emissions from lakes and streams in a subarctic catchment. Journal of Geophysical Research: Biogeosciences, 118(3), 1200-1207
Open this publication in new window or tab >>Integrating carbon emissions from lakes and streams in a subarctic catchment
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2013 (English)In: Journal of Geophysical Research: Biogeosciences, ISSN 2169-8953, Vol. 118, no 3, p. 1200-1207Article in journal (Refereed) Published
Abstract [en]

Northern inland waters emit CO2 and CH4 to the atmosphere but the importance of these emissions is poorly understood due to a lack of integrated catchment-scale estimates of carbon (C) emissions from lakes and streams. In this study we quantified the annual emission of CO2 and CH4 from 27 lakes and 23 stream segments in a 15km(2) subarctic catchment in northern Sweden. All lakes and streams were net sources of C to the atmosphere on an annual basis. Streams dominated (96%) the aquatic CO2 emission while lakes (61%) dominated the aquatic CH4 emission. Total aquatic C emission from the catchment was estimated to be 9.1gCm(-2)yr(-1) (98% as CO2). Although streams only accounted for 4% of the aquatic area in the catchment, they accounted for 95% of the total emission. The C emissions from lakes and streams were considerably larger than previously reported downstream waterborne export of C from the catchment, indicating that the atmospheric losses of C in the aquatic systems are an important component in the catchment C balance.

Place, publisher, year, edition, pages
Wiley-Blackwell, 2013
Keyword
subarctic, streams, lakes, CO2, CH4, emission
National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:umu:diva-82832 (URN)10.1002/jgrg.20092 (DOI)000325549900019 ()
Funder
Swedish Research Council, 621-2008-4390
Note

We acknowledge the contributions of NSERC (Canada), the Abisko Scientific Research Station (Sweden), Swedish Research Council, Swedish Environmental Protection Agency, and the Lund University GIS Centre for the funding of the lidar and DEM survey [cf. Hasan et al. 2012].

Available from: 2013-11-11 Created: 2013-11-11 Last updated: 2018-03-15Bibliographically 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, p. 501A-502AArticle 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
Vincent, A. G., Ilstedt, U., Vestergren, J., Giesler, R., Persson, P., Gröbner, G. & Schleucher, J. (2013). Phosphorus in forest soils: disentangling the chemistry of an essential nutrient. Forest facts (4)
Open this publication in new window or tab >>Phosphorus in forest soils: disentangling the chemistry of an essential nutrient
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2013 (English)In: Forest facts, no 4Article in journal (Refereed) Published
Place, publisher, year, edition, pages
SLU, 2013
Keyword
Phosphorus, forests, soil, nutrients, nuclear magnetic resonance (NMR), spectroscopy
National Category
Forest Science
Identifiers
urn:nbn:se:umu:diva-71209 (URN)
Available from: 2013-05-23 Created: 2013-05-23 Last updated: 2017-01-10Bibliographically approved
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