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- Ryberg, Eleonor E., et al.
(författare)
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Postglacial peatland vegetation succession in Store Mosse bog, south-central Sweden : An exploration of factors driving species change
- 2022
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Ingår i: Boreas. - : Wiley. - 0300-9483 .- 1502-3885. ; 51:3, s. 651-666
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Tidskriftsartikel (refereegranskat)abstract
- Boreal peatlands are facing significant changes in response to a warming climate. Sphagnum mosses are key species in these ecosystems and contribute substantially to carbon sequestration. Understanding the factors driving vegetation changes on longer time scales is therefore of high importance, yet challenging since species changes are typically affected by a range of internal and external processes acting simultaneously within the system. This study presents a high-resolution macrofossil analysis of a peat core from Store Mosse bog (south-central Sweden), dating back to nearly 10 000 cal. a BP. The aim is to identify factors driving species changes on multidecadal to millennial timescales considering internal autogenic, internal biotic and external allogenic processes. A set of independent proxy data was used as a comparison framework to estimate changes in the bog and regional effective humidity, nutrient input and cold periods. We found that Store Mosse largely follows the expected successional pathway for a boreal peatland (i.e. lake -> fen -> bog). However, the system has also been affected by other interlinked factors. Of interest, we note that external nutrient input (originating from dust deposition and climate processes) has had a negative effect on Sphagnum while favouring vascular plants, and increased fire activity (driven by allogenic and autogenic factors) typically caused post-fire, floristic wet shifts. These effects interactively caused a floristic reversal and near disappearance of a once-established Sphagnum community, during which climate acted as an indirect driver. Overall, this study highlights that the factors driving vegetation change within the peatland are multiple and complex. Consideration of the role of interlinked factors on Sphagnum is crucial for an improved understanding of the drivers of species change on short- and long-term scales.
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| 2. |
- Sjöström, Jenny K., 1978-, et al.
(författare)
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Late Holocene peat paleodust deposition in south-western Sweden : exploring geochemical properties, local mineral sources and regional aeolian activity
- 2022
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Ingår i: Chemical Geology. - : Elsevier. - 0009-2541 .- 1872-6836. ; 602
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Tidskriftsartikel (refereegranskat)abstract
- Atmospheric mineral dust not only interacts with the climate system by scattering incoming solar radiation and affecting atmospheric photochemistry, but also contributes critical nutrients to marine and terrestrial ecosystems. In a high-resolution analysis of paleodust deposition, peat development and soil dust sources, we assess the interplay between dust deposition and bog development of the Davidsmosse bog in south-western Sweden. Analyses of the 5400-year record (458 cm) included radiocarbon dating, bulk density, ash content, chemical and mineralogical composition and carbon stable isotopes, subsequently explored using principal component analysis. Fourteen dust events (DEs) were recorded (cal BP) in the peat sequence: 3580–3490; 3280; 3140; 3010–2840; 2740; 2610; 2480; 2340; 2240–2130; 1690; 1240; 960, 890–760, and 620–360. The majority of the DEs were coupled to increases in peat accumulation rates and increased nutrient content (N, P and K) suggesting that the DEs contributed with nutrients to the bog ecosystem, promoting increased accumulation. We also analyzed the chemical and mineral composition of potential mineral source deposits (separated into 6 grain-size fractions) from sites within a 4 km radius as well as aeolian dunes closer to the coast (25 km). The composition deposited on the present-day bog surface indicates that the bulk of the contemporary minerals have a local origin (<1.5 km), but the DEs may be of a more distant origin. The results also indicate that quartz and plagioclase feldspar content consistently increase with increasing grain-size, both in the source samples as well as in the peat sequence, and that the Si/Al ratio can be used to infer grain size changes in the peat. Two longer phases saw numerous DEs, between 2800 and 2130 cal BP and a stepwise increase from 960 towards 360 cal BP. The episodic character of the events, together with the inferred coarse grain size, suggest that the particles were deposited by (winter) storms. Future studies should include grain size analysis as well as a more in-depth comparison with regional paleo dust and storm records to increase knowledge on both transport processes (creep, saltation, suspension) and the climate processes driving late Holocene dust and storm events in Scandinavia.
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