| 1. |
- Kylander, Malin E., et al.
(författare)
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It's in your glass : a history of sea level and storminess from the Laphroaig bog, Islay (southwestern Scotland)
- 2020
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Ingår i: Boreas. - : Wiley. - 0300-9483 .- 1502-3885. ; 49:1, s. 152-167
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Tidskriftsartikel (refereegranskat)abstract
- Severe winter windstorms have become an increasingly common occurrence over recent decades in northwestern Europe. Although there exists considerable uncertainty, storminess is projected to increase in the future. On centennial to millennial time scales in particular, the mechanisms forcing storminess remain unsettled. We contribute to available palaeostorm records by reconstructing changes over the last 6670 years using a coastal peat sequence retrieved from the ombrotrophic Laphroaig bog on Islay, southwestern Scotland. We use a combination of ash content, grain size and elemental chemistry to identify periods of greater storminess, which are dated to 6605, 6290-6225, 5315-5085, 4505, 3900-3635, 3310-3130, 2920-2380, 2275-2190, 2005-1860, 1305-1090, 805-435 and 275 cal. a BP. Storm signals in the first half of the record up to similar to 3000 cal. a BP are mainly apparent in the grain-size changes. Samples from this time period also have a different elemental signature than those later in the record. We speculate that this is due to receding sea levels and the consequent establishment of a new sand source in the form of dunes, which are still present today. The most significant events and strongest winds are found during the Iron Ages Cold Epoch (2645 cal. a BP), the transition into, and in the middle of, the Roman Ages Warm Period (2235 and 1965 cal. a BP) and early in the Little Ice Age (545 cal. a BP). The Laphroaig record generally agrees with regionally relevant peat palaeostorm records from Wales and the Outer Hebrides, although the relative importance of the different storm periods is not the same. In general, stormier periods are coeval with cold periods in the region as evidenced by parallels with increased ice-rafted debris in the North Atlantic, highlighting that sea-ice conditions could impact future storminess and storm track position.
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| 2. |
- Kylander, Malin E., 1977-, et al.
(författare)
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Storm chasing : Tracking Holocene storminess in southern Sweden using mineral proxies from inland and coastal peat bogs
- 2023
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Ingår i: Quaternary Science Reviews. - : Elsevier BV. - 0277-3791 .- 1873-457X. ; 299, s. 107854-
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 3. |
- Allan, Mohammed, et al.
(författare)
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High-resolution reconstruction of atmospheric deposition of trace metals and metalloids since AD 1400 recorded by ombrotrophic peat cores in Hautes-Fagnes, Belgium
- 2013
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Ingår i: Environmental Pollution. - : Elsevier BV. - 0269-7491 .- 1873-6424. ; 178, s. 381-394
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Tidskriftsartikel (refereegranskat)abstract
- The objective of our study was to determine the trace metal accumulation rates in the Misten bog, Hautes-Fagnes, Belgium, and assess these in relation to established histories of atmospheric emissions from anthropogenic sources. To address these aims we analyzed trace metals and metalloids (Pb, Cu, Ni, As, Sb, Cr, Co, V, Cd and Zn), as well as Pb isotopes, using XRF, Q-ICP-MS and MC-ICP-MS, respectively in two 40-cm peat sections, spanning the last 600 yr. The temporal increase of metal fluxes from the inception of the Industrial Revolution to the present varies by a factor of 5-50, with peak values found between AD 1930 and 1990. A cluster analysis combined with Pb isotopic composition allows the identification of the main sources of Pb and by inference of the other metals, which indicates that coal consumption and metallurgical activities were the predominant sources of pollution during the last 600 years.(c) 2013 Elsevier Ltd. All rights reserved.
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| 4. |
- Anderson, N.J., et al.
(författare)
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Landscape-Scale Variability of Organic Carbon Burial by SW Greenland Lakes
- 2019
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Ingår i: Ecosystems (New York. Print). - : Springer. - 1432-9840 .- 1435-0629. ; 22:8, s. 1706-1720
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Tidskriftsartikel (refereegranskat)abstract
- Lakes are a key feature of arctic landscapes and can be an important component of regional organic carbon (OC) budgets, but C burial rates are not well estimated. 210Pb-dated sediment cores and carbon and organic matter (as loss-on-ignition) content were used to estimate OC burial for 16 lakes in SW Greenland. Burial rates were corrected for sediment focusing using the 210Pb flux method. The study lakes span a range of water chemistries (conductivity range 25–3400 µS cm−1), areas (< 4–100 ha) and maximum depths (~ 10–50 m). The regional average focusing-corrected OC accumulation rate was ~ 2 g C m−2 y−1 prior to ~ 1950 and 3.6 g C m−2 y−1 after 1950. Among-lake variability in post-1950 OC AR was correlated with in-lake dissolved organic carbon concentration, conductivity, altitude and location along the fjord. Twelve lakes showed an increase in mean OC AR over the analyzed time period, ~ 1880–2000; as the study area was cooling until recently, this increase is probably attributable to other global change processes, for example, altered inputs of N or P. There are ~ 20,000 lakes in the study area ranging from ~ 1 ha to more than 130 km2, although over 83% of lakes are less than 10 ha. Extrapolating the mean post-1950 OC AR (3.6 g C m−2 y−1) to all lakes larger than 1000 ha and applying a lower rate of ~ 2 g C m−2 y−1 to large lakes (> 1000 ha) suggests a regional annual lake OC burial rate of ~ 10.14 × 109 g C y−1 post 1950. Given the low C content of soils in this area, lakes represent a substantial regional C store.
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| 5. |
- Anderson, N. John, et al.
(författare)
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The Arctic in the Twenty-First Century : Changing Biogeochemical Linkages across a Paraglacial Landscape of Greenland
- 2017
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Ingår i: BioScience. - : Oxford University Press. - 0006-3568 .- 1525-3244. ; 67:2, s. 118-133
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Tidskriftsartikel (refereegranskat)abstract
- The Kangerlussuaq area of southwest Greenland encompasses diverse ecological, geomorphic, and climate gradients that function over a range of spatial and temporal scales. Ecosystems range from the microbial communities on the ice sheet and moisture-stressed terrestrial vegetation (and their associated herbivores) to freshwater and oligosaline lakes. These ecosystems are linked by a dynamic glacio-fluvial-aeolian geomorphic system that transports water, geological material, organic carbon and nutrients from the glacier surface to adjacent terrestrial and aquatic systems. This paraglacial system is now subject to substantial change because of rapid regional warming since 2000. Here, we describe changes in the eco-and geomorphic systems at a range of timescales and explore rapid future change in the links that integrate these systems. We highlight the importance of cross-system subsidies at the landscape scale and, importantly, how these might change in the near future as the Arctic is expected to continue to warm.
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| 6. |
- Bertrand, Sebastien, et al.
(författare)
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Inorganic geochemistry of lake sediments : a review of analytical techniques and guidelines for data interpretation
- 2024
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Ingår i: Earth-Science Reviews. - : Elsevier. - 0012-8252 .- 1872-6828. ; 249
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Forskningsöversikt (refereegranskat)abstract
- Inorganic geochemistry is a powerful tool in paleolimnology. It has become one of the most commonly used techniques to analyze lake sediments, particularly due to the development and increasing availability of XRF core scanners during the last two decades. It allows for the reconstruction of the continuous processes that occur in lakes and their watersheds, and it is ideally suited to identify event deposits. How earth surface processes and limnological conditions are recorded in the inorganic geochemical composition of lake sediments is, however, relatively complex. Here, we review the main techniques used for the inorganic geochemical analysis of lake sediments and we offer guidance on sample preparation and instrument selection. We then summarize the best practices to process and interpret bulk inorganic geochemical data. In particular, we emphasize that log-ratio transformation is critical for the rigorous statistical analysis of geochemical datasets, whether they are obtained by XRF core scanning or more traditional techniques. In addition, we show that accurately interpreting inorganic geochemical data requires a sound understanding of the main components of the sediment (organic matter, biogenic silica, carbonates, lithogenic particles) and mineral assemblages. Finally, we provide a series of examples illustrating the potential and limits of inorganic geochemistry in paleolimnology. Although the examples presented in this paper focus on lake and fjord sediments, the principles presented here also apply to other sedimentary environments.
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| 7. |
- Biester, Harald, et al.
(författare)
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Mercury in mires
- 2006
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Ingår i: Peatlands. - : Elsevier. - 9780080468051 - 9780444528834 ; , s. 465-478
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Bokkapitel (refereegranskat)abstract
- This chapter illustrates that a better understanding of the behavior of mercury in the environment is needed for a number of reasons. For example, increased biomagnification of mercury in aquatic food chains, especially in fish, and enhanced accumulation in remote areas such as the Arctic have been observed in the last few decades. Mercury toxicity in aquatic ecosystems is of particular concern, with the role of methylmercury (MeHg) being critical. This compound can be concentrated by more than a million times in the aquatic food chain. Biogeochemical studies and monitoring programs that include direct measurements of wet deposition or indirect measurements based on biomonitoring of forest mosses, have established that anthropogenic activities have affected the global cycling of mercury. Although a precise link has yet to be made between the increased content of mercury in biota and the increased accumulation rates observed in natural environmental archives, such as peat, lake sediments, and glacial ice, there is broad consensus that these archives provide a means to reconstruct atmospheric deposition trends at local, regional, and global scales.
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| 8. |
- Biester, Harald, et al.
(författare)
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Modeling the Past Atmospheric Deposition of Mercury Using Natural Archives
- 2007
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 41:14, s. 4851-4860
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Tidskriftsartikel (refereegranskat)abstract
- Historical records of mercury (Hg) accumulation in lake sediments and peat bogs are often used to estimate human impacts on the biogeochemical cycling of mercury. On the basis of studies of lake sediments, modern atmospheric mercury deposition rates are estimated to have increased by a factor of 3-5 compared to background values: i.e., from about 3-3.5 g Hg m-2 yr-1 to 10-20 g Hg m-2 yr-1. However, recent studies of the historical mercury record in peat bogs suggest significantly higher increases (9-400 fold, median 40×), i.e., from about 0.6-1.7 g Hg m-2 yr -1 to 8-184 g Hg m-2 yr -1. We compared published data of background and modern mercury accumulation rates derived from globally distributed lake sediments and peat bogs and discuss reasons for the differences observed in absolute values and in the relative increase in the industrial age. Direct measurements of modern wet mercury deposition rates in remote areas are presently about 1-4 g m-2 yr -1, but were possibly as high as 20 g Hg m-2 yr -1 during the 1980s. These values are closer to the estimates of past deposition determined from lake sediments, which suggests that modern mercury accumulation rates derived from peat bogs tend to over-estimate deposition. We suggest that smearing of 210Pb in the uppermost peat sections contributes to an underestimation of peat ages, which is the most important reason for the overestimation of mercury accumulation rates in many bogs. The lower background mercury accumulation rates in peat as compared to lake sediments we believe is the result of nonquantitative retention and loss of mercury during peat diagenesis. As many processes controlling time-resolved mercury accumulation in mires are still poorly understood, lake sediments appear to be the more reliable archive for estimating historical mercury accumulation rates.
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| 9. |
- Bindler, Richard, et al.
(författare)
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Beyond the peat : synthesizing peat, lake sediments and soils in studies of the Swedish environment
- 2006
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Ingår i: Peatlands. - : Elsevier. - 9780080468051 - 9780444528834 ; , s. 431-448
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This chapter illustrates on comparing peat and lake sediment records and linking the quantitative record of metals in peat to contemporary environmental problems. Quantifying metal records in peat has been an important step, but new research needs to move beyond this and consider how to apply these data. Lead analyses, including stable isotopes, are now fairly routine and based on these analyses the historical trends of lead deposition are now well established in peat, lake sediments and even glacial ice. The biogeochemical cycling of lead has also been well researched, which allows making this link between the historical lead record and soil biogeochemistry. Because peat and lake sediments seem to record the same changes in mercury deposition, there is similar promise in linking the long-term peat record of mercury and other metals with biogeochemical cycling of mercury and other important metals in forests and soils.
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| 10. |
- Bindler, Richard, et al.
(författare)
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Bridging the gap between ancient metal pollution and contemporary biogeochemistry
- 2008
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Ingår i: Journal of Paleolimnology. - : Springer. - 0921-2728 .- 1573-0417. ; 40:3, s. 755-770
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Tidskriftsartikel (refereegranskat)abstract
- Paleolimnology provides long-term data that are often essential for understanding the current state of the environment. Even though there is great potential, paleolimnology is rarely used together with process-related studies to solve issues regarding cycling of elements in the environment. Clearly, this is a drawback because the cycling of many elements, which cause great concern in the present-day environment, was altered long before the advent of monitoring programs. The pioneering work of C.C. Patterson and his colleagues emphasized the importance of a long-term perspective for understanding the current cycling of metals, with a focus on lead, and in particular for estimating background concentrations and human-related impacts in the environment. In Sweden the first traces of atmospheric lead pollution are found in lake sediments dated to about 3500 years ago. The long-term changes in the pollution lead record in lake sediments led us to consider how lead biogeochemistry has changed over time in response to this historical deposition‹where has this lead gone, and how much does this lead contribute to the present-day biogeochemical cycling of lead? How was lead distributed in Œpre-industrial¹ soils or more properly in natural soils not impacted by atmospheric pollution? There are many studies that have examined the effects of increased metal concentrations on soil biota, but what are the appropriate background conditions for comparison? Using lake sediments as our foundation we have analyzed lead, including its stable isotopes, in other environmental compartments, including peat, soil, and a range of boreal forest plant species, to develop a better understanding of the fate of lead derived from long-term pollution. Three important conclusions from our studies in Sweden are: (1) atmospheric lead deposition rates during the 20th century were 100 to as much as 1000 times higher than natural deposition rates a few thousand years ago. Even with stricter emission standards during the past three decades and the resultant reductions in deposition, lead deposition rates today are still 10100 times greater than natural rates. This increase in deposition rates modeled from sediment and peat records is of a similar scale to estimated changes in body burdens of lead in modern versus ancient humans. (2) In Europe about half of the cumulative burden of atmospherically deposited lead was deposited before industrialization. In southern Sweden the cumulative burden of pollution lead during the past 3500 years is 25 g Pb m-2 and in the Œpristine¹ northern parts of the country there is about 1 g Pb m-2. (3) Predicted recovery rates for soils are slow; in the cold climate of Scandinavia, we find that the soil surface (O horizon), where most soil biota reside, retains lead deposited over the past 150500 years. Therefore, although lead deposition rates in Europe, as well as N. America, are only 10% of those a few decades ago, it will take several decades or longer for lead concentrations in soils to respond appreciably. The slow turnover rates for lead in the environment and gradual immobilization of lead in deeper soil mineral horizons also inhibits a loss of lead to surface waters in areas removed from point sources.
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