Store Mosse Research Articles

Assessing the diversity of nematodes in the Store Mosse National Park (Sweden) using metabarcoding

The Store Mosse National Park in the south of Sweden was surveyed for nematode diversity and distribution using DNA metabarcoding. Fifty samples were collected from five vegetation types in the park across a range of habitats (e.g. soil, litter, lichens, sphagnum and roots). The other habitats, aside from soil and litter, were sampled in order to capture the diversity of nematodes that may be uniquely associated with them. Nematodes were characterised using the V7-V8 variable domain (~ 350 bp) of the 18S ribosomal RNA gene. We identified 46 families, 76 genera (21 new to Swedish fauna) and 60 species (31 new to Swedish fauna). Some nematodes showed strong associations with their habitats, especially at the species level. Although soil and litter supported the most diverse nematode communities, our results support a strong justification for sampling across different media types to quantify nematode diversity accurately. Soil and litter communities showed high levels of stability with balanced distribution of all the various trophic and coloniser-persister groups.

Holocene wet shifts in NW European bogs: evidence for the roles of external forcing and internal feedback from a high‐resolution study of peat properties, plant macrofossils and testate amoebae

ABSTRACTTwo conspicuous wet shifts in the peat stratigraphy of Store Mosse in southern Sweden, associated with bog‐wide changes in vegetation and degree of peat decomposition, were analysed at high resolution. The bog‐surface wetness (BSW) proxy data (organic matter bulk density, C/N ratio, plant macrofossils and testate amoebae) highlight the importance of interactions between vegetation composition, microtopography and degree of peat decomposition, and show that the bog system operated consistently during the two wet shifts (dated to c. 2700 and 1000 cal a bp) despite different internal and external conditions. A sensitive bog‐system state, associated with a degraded microtopography and well‐decomposed surface peat with low hydrological conductivity developed during sustained dry conditions, probably contributed to the large BSW amplitudes registered. Comparable bog systems are expected to operate in the same way, and regionally high sensitivity that developed in response to atmospheric circulation changes may partly explain synchronous registration of wet shifts. The wet shifts in Store Mosse were attributed to solar and volcanic forcing, respectively, and wet shifts of similar magnitude registered in other NW European bogs are likely to also have been externally forced.

Storm chasing: Tracking Holocene storminess in southern Sweden using mineral proxies from inland and coastal peat bogs

Severe extratropical winter storms are a recurrent feature of the European climate and cause widespread socioeconomic losses. Due to insufficient long-term data, it remains unclear whether storminess has shown a notable response to changes in external forcing over the past millennia, which impacts our ability to project future storminess in a changing climate. Reconstructing past storm variability is essential to improving our understanding of storms on these longer, missing timescales. Peat sequences from coastal ombrotrophic bogs are increasingly used for this purpose, where greater quantities of coarser grained beach sand are deposited by strong winds during storm events. Moving inland however, storm intensity decreases, as does sand availability, muting potential paleostorm signals in bogs. We circumvent these issues by taking the innovative approach of using mid-infrared (MIR) spectral data, supported by elemental information, from the inorganic fraction of Store Mosse Dune South (SMDS), a 5000-year-old sequence from a large peatland located in southern Sweden. We infer past changes in mineral composition and thereby, the grain size of the deposited material. The record is dominated by quartz, whose coarse nature was confirmed through analyses of potential local source sediments. This was supported by further mineralogical and elemental proxies of atmospheric input. Comparison of SMDS with within-bog and regionally relevant records showed that there is a difference in proxy and site response to what should be similar timing in shifts in storminess over the ∼100 km transect considered. We suggest the construction of regional storm stacks, built here by applying changepoint modelling to four transect sites jointly. This modelling approach has the effect of reinforcing signals in common while reducing the influence of random noise. The resulting Southern Sweden-Storm Stack dates stormier periods to 4495–4290, 3880–3790, 2885–2855, 2300–2005, 1175–1065 and 715-425 cal yr BP. By comparing with a newly constructed Western Scotland-Storm Stack and proximal dune records, we argue that regional storm stacks allow us to better compare past storminess over wider areas, gauge storm track movements and by extension, increase our understanding of the drivers of storminess on centennial to millennial timescales.

Postglacial peatland vegetation succession in Store Mosse bog, south‐central Sweden: An exploration of factors driving species change

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.

9000 years of changes in peat organic matter composition in Store Mosse (Sweden) traced using FTIR‐ATR

Store Mosse (the ‘Great Bog’ in Swedish) is one of the most extensive bog complexes in southern Sweden (~77 km2), where pioneering palaeoenvironmental research has been carried out since the early 20th century. This includes, for example, vegetation changes, carbon and nitrogen dynamics, peat decomposition, atmospheric metal pollution, mineral dust deposition, dendrochronology, and tephrochronology. Even though organic matter (OM) represents the bulk of the peat mass and its compositional change has the potential to provide crucial ecological information on bog responses to environmental factors, peat OM molecular composition has not been addressed in detail. Here, a 568‐cm‐deep peat sequence was studied at high resolution, by attenuated reflectance Fourier‐transform infrared spectroscopy (FTIR‐ATR) in the mid‐infrared region (4000–400 cm–1). Principal components analysis was performed on selected absorbances and change‐point modelling was applied to the records to determine the timing of changes. Four components accounted for peat composition: (i) depletion/accumulation of labile (i.e. carbohydrates) and recalcitrant (i.e. lignin and other aromatics, aliphatics, organic acids and some N compounds) compounds, due to peat decomposition; (ii) variations in N compounds and carbohydrates; (iii) residual variation of lignin and organic acids; and (iv) residual variation of aliphatic structures. Peat decomposition showed two main patterns: a long‐term trend highly correlated to peat age (r = 0.87), and a short‐term trend, which showed five main phases of increased decomposition (at ~8.4–8.1, ~7.0–5.6, ~3.5–3.1, ~2.7–2.1 and ~1.6–1.3 ka) – mostly corresponding to drier climate and its effect on bog hydrology. The high peat accumulation event (~5.6–3.9 ka), described in earlier studies, is characterized by the lowest degree of peat decomposition of the whole record. Given that FTIR‐ATR is a quick, non‐destructive, cost‐effective technique, our results indicate that it can be applied in a systematic way (including multicore studies) to peat research and provide relevant information on the evolution of peatlands.

Paleodust deposition and peat accumulation rates – Bog size matters

We present a high-resolution peat paleodust and accumulation rate record spanning the last 8300 years from Draftinge Mosse (400 ha), southern Sweden (57°06′27.6”N 13°42′54.1″E). The record was analysed for peat accumulation rates (PAR), elemental concentrations, mineralogy, and plant macrofossil content. Five periods of increased mineral deposition were recorded. The first event occurred between ~6280 and ~5570 cal BP, during the fen to bog transition. This is followed by four atmospheric mineral dust events (DE) which were recorded in the ombrotrophic section of the sequence at (cal BP): ~2200; ~1385–1150; ~830–590, and from ~420 to the present. Statistical analysis and elemental ratios indicated that both the mineralogy and grain size shifted when the system transitioned from fen into bog, showing that the governing transport process shifted with the peatland succession stages. This highlights the importance of identifying peatland succession stages within peat paleodust studies. Following all four DE, increases in PAR were observed, implying a coupling to dust deposition. Comparison of DE and PAR with a paleodust record from Store Mosse, a 20 times larger bog located ca 18 km away (Kylander et al. 2016), showed that both PAR and dust deposition are largely represented by single-core reconstructions, indicating that they are driven by a common climate forcing mechanism. However, higher PAR and dust deposition rates were observed in the more moderately sized Draftinge Mosse, suggesting that the size of the bog is important to consider in peat paleodust studies. Furthermore, the smaller bog responded more rapidly to hydrological changes, indicating that the size of the bog affects its' buffering capacity. Authigenic carbonates, observed here during episodes of rapid peat growth, coincide with changes in REE ratios, indicating that authigenic peat processes potentially cause REE fractionation.

Mineral dust as a driver of carbon accumulation in northern latitudes

Peatlands in northern latitudes sequester one third of the world’s soil organic carbon. Mineral dusts can affect the primary productivity of terrestrial systems through nutrient transport but this process has not yet been documented in these peat-rich regions. Here we analysed organic and inorganic fractions of an 8900-year-old sequence from Store Mosse (the “Great Bog”) in southern Sweden. Between 5420 and 4550 cal yr BP, we observe a seven-fold increase in net peat-accumulation rates corresponding to a maximum carbon-burial rate of 150 g C m−2 yr−1 – more than six times the global average. This high peat accumulation event occurs in parallel with a distinct change in the character of the dust deposited on the bog, which moves from being dominated by clay minerals to less weathered, phosphate and feldspar minerals. We hypothesize that this shift boosted nutrient input to the bog and stimulated ecosystem productivity. This study shows that diffuse sources and dust dynamics in northern temperate latitudes, often overlooked by the dust community in favour of arid and semi-arid regions, can be important drivers of peatland carbon accumulation and by extension, global climate, warranting further consideration in predictions of future climate variability.

Potentials and problems of building detailed dust records using peat archives: An example from Store Mosse (the “Great Bog”), Sweden

Mineral dust deposition is a process often overlooked in northern mid-latitudes, despite its potential effects on ecosystems. These areas are often peat-rich, providing ample material for the reconstruction of past changes in atmospheric deposition. The highly organic (up to 99% in some cases) matrix of atmospherically fed mires, however, makes studying the actual dust particles (grain size, mineralogy) challenging. Here we explore some of the potentials and problems of using geochemical data from conservative, lithogenic elements (Al, Ga, Rb, Sc, Y, Zr, Th, Ti and REE) to build detailed dust records by using an example from the 8900-yr peat sequence from Store Mosse (the “Great Bog”), which is the largest mire complex in the boreo-nemoral region of southern Sweden. The four dust events recorded at this site were elementally distinct, suggesting different dominant mineral hosts. The oldest and longest event (6385–5300calyr BP) sees a clear signal of clay input but with increasing contributions of mica, feldspar and middle-REE-rich phosphate minerals over time. These clays are likely transported from a long-distance source (<100km). While dust deposition was reduced during the second event (5300–4370calyr BP), this is the most distinct in terms of its source character with [Eu/Eu∗]UCC revealing the input of plagioclase feldspar from a local source, possibly active during this stormier period. The third (2380–2200calyr BP) and fourth (1275–1080calyr BP) events are much shorter in duration and the presence of clays and heavy minerals is inferred. Elemental mass accumulation rates reflect these changes in mineralogy where the relative importance of the four dust events varies by element. The broad changes in major mineral hosts, grain size, source location and approximated net dust deposition rates observed in the earlier dust events of longer duration agree well with paleoclimatic changes observed in northern Europe. The two most recent dust events are much shorter in duration, which in combination with evidence of their local and regional character, may explain why they have not been seen elsewhere.

A novel geochemical approach to paleorecords of dust deposition and effective humidity: 8500 years of peat accumulation at Store Mosse (the “Great Bog”), Sweden

Both bog surface wetness and atmospheric dust deposition are intricately linked to changes in the hydrological cycle and pairing these types of records at the same site provides complementary information. Here a peat core from Store Mosse in southern Sweden covering the last 8500 years was used to make a high-resolution paleoclimate reconstruction based on a combination of bog development, colourimetric humification and inorganic geochemistry data. The coupling of Principal Component Analysis with changepoint modelling allowed for precise linking of changes in bog surface wetness and dust deposition records.A long-term trend towards warm (and possibly wet) conditions starts ca 8150 cal yr BP and culminates with the most pronounced conditions from 6900 to 6600 cal yr BP. The most significant arid period at Store Mosse occurred between 6500 and 5600 cal yr BP during which dust deposition was significantly higher. Wetter conditions dominate from 5500 to 4980 cal yr BP as the transition from the Hypsithermal and into the Neoglacial is made. After a shift to drier conditions, humification enters a more stable period that lasts from 4525 until 3200 cal yr BP. It is during this time that the first possible anthropogenic dust signals occur at ca 4200 cal yr BP. From 3200 cal yr BP to present humification generally shows a long-term decline moving towards wetter conditions. The main exceptions are during the transition from the Neoglacial to Roman Warm Period which is registered as a significantly wetter period and two dry periods recorded 2365 to 2155 cal yr BP and 1275–1105 cal yr BP. In general, the observed changes agree well with regional records of effective humidity and temperature. The high temporal resolution of the Store Mosse record reveals that palaeoclimatic change over the last 8500 years in southern Sweden has had a complex and variable structure.

Exploring the patterns and causes of land use changes in south-west Sweden

To study the causes of agricultural declines in south-west Sweden, a multi-proxy study including pollen analysis, bog surface wetness indicators and aeolian sediment influx reconstructions was carried out on the Store Mosse Bog, situated on the coastal plain of Halland. Patterns of agricultural changes during the past 6,000 years from this study were compared to one additional site on the coastal plain (Undarsmosse Bog) and to four sites in the forested upland region. First, we compared land use activity on the coastal plain and in upland regions of south-west Sweden. Three periods with reduced agricultural activities were observed, primarily in records from the coastal plain. Next, the causes for these declines were studied by comparing land use indicators in the pollen records from the Store Mosse and Undarsmosse peat bogs to independent climatic reconstructions based on the same core material (past storm activity based on aeolian sediment influx onto the peat bogs; bog surface wetness reconstructed from organic bulk density measurements). Since the climatic reconstructions and pollen analysis were carried out on the same peat cores, a direct comparison between the timing of climatic events and land use changes was possible. Results indicate that climatic perturbations prior to ca. 1,000 years ago contributed to or possibly caused agricultural declines. The agricultural expansions near the Store Mosse and Undarsmosse bogs from 3000 to 2600 cal. yrs b.p. ended at the time when climatic proxy indicators recorded climatic instability (from ca 2600 to 2200 cal. yrs b.p.). The same sequence of events was recorded around 1500 cal. yrs b.p. and from 1200 to 1000 cal. yrs b.p., suggesting a climatic cause for these agricultural declines as well. The well-known climatic perturbations associated with the Little Ice Age, however, did not have a visible impact on agricultural activities. By this time, advances in land use knowledge and technology may have drastically diminished society’s sensitivity to climatic changes.

Reply to comment by William Shotyk on “Does within‐bog spatial variability of mercury and lead constrain reconstructions of absolute deposition rates from single peat records? The example of Store Mosse, Sweden”

Reply to comment by William Shotyk on Does within-bog spatial variability of mercury and lead constrain reconstructions of absolute deposition rates from single peat records? The example of Store Mosse, Sweden

Comment on “Does within‐bog spatial variability of mercury and lead constrain reconstructions of absolute deposition rates from single peat records? The example of Store Mosse, Sweden,” by Richard Bindler, Malin Klarqvist, Jonatan Klaminder, and Johannes Förster

Comment on “Does within‐bog spatial variability of mercury and lead constrain reconstructions of absolute deposition rates from single peat records? The example of Store Mosse, Sweden,” by Richard Bindler, Malin Klarqvist, Jonatan Klaminder, and Johannes Förster

Does within‐bog spatial variability of mercury and lead constrain reconstructions of absolute deposition rates from single peat records? The example of Store Mosse, Sweden

Recent research has recognized the utility of the peat record in ombrotrophic bogs to reconstruct past changes in the atmospheric deposition of, for example, lead and mercury. Frequently, these reconstructions rely only on single peat records to make assessments of regional deposition rates. The surface of a bog is not a uniform feature; rather, vegetation and micro‐topography vary over small spatial scales, which can affect the interception and retention of atmospheric deposition, and over relatively short timescales. Analyses of nine hummock cores collected from a 2000 m2 area on one bog, Store Mosse, show that concentrations and cumulative inventories (past 110 years) of lead and mercury vary by a factor of 2 for lead (0.75 to 1.40 g Pb m−2, three cores) and 4 for mercury (0.85 to 3.4 mg Hg m−2, nine cores). The range of values within Store Mosse is greater than the difference between any one core and the metal inventories from either Dumme Mosse (0.95 g Pb m−2 and 2.0 mg Hg m−2) or Trollsmosse (1.6 mg Hg m−2), each about 60 km distant. Although the general temporal trends are similar in all cores, our data indicate that single reconstructions do not necessarily provide a representative flux for the bog as a whole. To overcome the potential constraints of single records, we suggest incorporating data from multiple sites or at least multiple cores in order to scale up to regionally valid models of past metal deposition.

Carbon sequestration in peatland: patterns and mechanisms of response to climate change

AbstractThe response of peatlands to changes in the climatic water budget is crucial to predicting potential feedbacks on the global carbon (C) cycle. To gain insight on the patterns and mechanisms of response, we linked a model of peat accumulation to a model of peatland hydrology, then applied these models to empirical data spanning the past 5000 years for the large mire Store Mosse in southern Sweden. We estimated parameters for C sequestration and height growth by fitting the peat accumulation model to two age profiles. Then, we used independent reconstruction of climate wetness and model reconstruction of bog height to examine changes in peatland hydrology. Reconstructions of C sequestration showed two distinct patterns of behaviour: abrupt increases associated with major transitions in vegetation and dominant Sphagnum species (fuscum, rubellum–fuscum and magellanicum stages), and gradual decreases associated with increasing humification of newly formed peat. Carbon sequestration rate ranged from a minimum of 14 to a maximum of 72 g m−2 yr−1, with the most rapid changes occurring in the past 1000 years. Vegetation transitions were associated with periods of increasing climate wetness during which the hydrological requirement for increased seepage loss was met by rise of the water table closer to the peatland surface, with the indirect result of enhancing peat formation. Gradual decline in C sequestration within each vegetation stage resulted from enhanced litter decay losses from the near‐surface layer. In the first two vegetation stages, peatland development (i.e., increasing surface gradient) and decreasing climate wetness drove a gradual increase in thickness of the unsaturated, near‐surface layer, reducing seepage water loss and peat formation. In the most recent vegetation stage, the surface diverged into a mosaic of wet and dry microsites. Despite a steady increase in climate wetness, C sequestration declined rapidly. The complexity of response to climate change cautions against use of past rates to estimate current or to predict future rates of peatland C sequestration. Understanding interactions among hydrology, surface structure and peat formation are essential to predicting potential feedback on the global C cycle.

Mass balance and nitrogen accumulation in hummocks on a South Swedish bog during the late Holocene

Two peat cores from the Store Mosse mire in the central part of South Sweden have been analyzed for dry bulk density, carbon, and nitrogen They cover the development of the peat mound from the time of the conversion of the initial fen to an ombrotrophic bog at 5450 BP through three different bog stages, the Fuscum. the Rubellum‐Fuscum and the Magellanicum bog stages, each one characterized by a specific macrofossil assemblageAll N supplied to the bog surface is assumed to be contained in the organic matter At the beginning of the Magellanicum bog stage, 1000 BP, the nitrogen accumulation rate increased from an earlier value of ca 0.4 g m–2 yr–1 to 0.8 g m–2 yr–1 These accumulation rates for N have been used to establish time scales for the periods between the 14C‐datingsThe estimated litter deposition rate in the hummocks is 120 g m–2 yr–1 in the two older bog stages and 270 g m–2 yr–1 in the Magellanicum bog stage The decay losses in the acrotelm increased, as a proportion of the addition, with time through each one of the bog stages The range of variation in the cores for the acrotelm decay losses was 25‐80%. and the annual input of organic matter to the catotelm, 30‐130 g m–2 These ranges are greater than those found among recent bog hummocks in NW Europe and North America The decay losses during 5000 yr in the catotelm may not have exceeded 20% of the original input The over‐all net rate of accumulation of C was highest, ca 40 g m–2 yr–1, at the beginning of the Fuscum bog stageThe changes in the macrofossil assemblages are all associated with rapid increases in the peat accumulation rate, but decreases in accumulation rate are not At the conversion from fen to bog the increased input of organic matter to the catotelm depended on expansion of Sphagnum fuscum which formed a decay resistant litter Later increases depended on rapid rises of the mean water table, resulting in shorter residence times and smaller decay losses from the acrotelm The periods of decreases in input of organic matter to the catotelm depended on longer residence times in the acrotelm when the water table fell relative to the bog surface However, comparisons with recent conditions suggest that the variation in mean water level relative to the surface may not have exceeded 10‐15 cm

Bog development and environmental conditions as shown by the stratigraphy of Store Mosse mire in southern Sweden

Macrofossil analyses, pollen analyses, and 14C datings were carried out on profiles from a bog complex in southern Sweden. The development started with a Carex fen c. 6,000 B. P. which transformed to bog c. 1,000 years later. The bog has developed through three stages separated by highly humified peat layers, recurrence surfaces, 3 and 2m below the present bog surface, and formed c. 2,500 and 1,200 B. P., respectively. The fen formation and the initiation of the last two bog stages were contemporaneous with high water levels in lakes of the region. The transition to bog and the formation of the two highly humified peat layers may be related to low water levels in lakes. It is probable that changes in the development of the mire were caused by the climate, since varying water levels are thought to be dependent on variations in the climate.

Fossil Plant Communities and Regeneration Patterns on a Raised Bog in South Sweden

SUMMARY (1) The Store Mosse mire has developed during the last 5000 years, with three bog stages separated from each other by vegetation producing highly humified peat layers. (2) The Fuscum bog stage at the bottom was dominated by relatively dry growing communities with Sphagnum fuscum. The Rubellum-Fuscum bog stage had several different communities with Sphagnum fuscum, S. rubellum and S. sect. Cuspidata. In the Magellanicum bog stage, hummocks, occupied by Sphagnum imbricatum, S.fuscum and S. rubellum, had a restricted distribution. They were joined in hummock strings. Sphagnum magellanicum was the most important species in the intervening hollows, but even Sphagnum cuspidatum occurred. (3) The peat-forming communities of the bog show an upward trend comparable with the east-west gradient found in present day bog communities. This differentiation may be related to increasing oceanicity. (4) Hollows are supposed to be secondary features, which are developed when environmental conditions give rise to an increase of water on the bog surface. No cyclic, autogenic regeneration between hummock and hollow communities was observed. (5) In the Magellanicum bog stage two types of bog growth can be distinguished. In the

Recognition of peat-forming plant communities from their peat deposits in two south Swedish bog complexes

Peat samples, 3 015 from 103 boring points, on two mires (Akhult mire, Store Mosse mire) south Sweden, have been subjected to macrofossil analysis. Based on plant remains, 9 peat groups were distinguished in the field. A further classification using phytosociological methods revealed 29 peat types. The affinities between the peat types were determined from TABORD classification and a Reciprocal Averaging ordination. The primary floristic differentiation is correlated with a gradient from treeless-to wooded stands, which coincides largely with the mire expanse-mire margin gradient. The poor-rich gradient seems to parallel the treeless-wooded gradient as well and may reflect the natural conditions in this mire before it was affected by man. The hummock-mud-bottom gradient is easy to distinguish in peat, formed by bog communities, but is not distinct in peat formed by fen communities and impossible to detect in peat dominated by wood remains. The amount of identifiable remains depends on the decomposition, which is determined by (1) the period of time the plant litter stays in the acrotelm, and (2) the nutrient status. The decomposition is greatest in fen-peat with abundant wood remains. This probably depends on a good supply of oxygen caused by greater horizontal water movements and better nutrient status.