| 1. |
- Rydberg, Johan, 1976-, et al.
(författare)
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Climate driven release of carbon and mercury from permafrost mires increases mercury loading to sub-arctic lakes
- 2010
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 408:20, s. 4778-4783
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Tidskriftsartikel (refereegranskat)abstract
- In sub-arctic and arctic regions mercury is an element of concern for both wildlife and humans. Over thousands of years large amounts of atmospherically deposited mercury, both from natural and anthropogenic sources, have been sequestered together with carbon in northern peatlands. Many of these peatlands are currently underlain by permafrost, which controls mire stability and hydrology. With the ongoing climate change there is concern that permafrost thawing will turn large areas of these northern peatlands from carbon/mercury-sinks into much wetter carbon/mercury-sources. Here we can show that such a change in mire structure in the sub-arctic Stordalen mire in northern Sweden actually is responsible for an increased export of mercury to the adjacent lake Inre Harrsjön. We also show that sediment mercury accumulation rates during a warm period in the pre-industrial past were higher than in the 1970s when atmospheric input peaked, indicating that in areas with permafrost, climate can have an effect on mercury loading to lakes as large as anthropogenic emissions. Thawing of permafrost and the subsequent export of carbon is a widespread phenomenon, and the projection is that it will increase even more in the near future. Together with our observations from Stordalen, this makes northern peatlands into a substantial source of mercury, at risk of being released into sensitive arctic freshwater and marine systems.
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| 2. |
- Rydberg Sterner, Therese, et al.
(författare)
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The Gothenburg H70 Birth cohort study 2014-16: design, methods and study population.
- 2019
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Ingår i: European journal of epidemiology. - : Springer Science and Business Media LLC. - 1573-7284 .- 0393-2990. ; 34:2, s. 191-209
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Tidskriftsartikel (refereegranskat)abstract
- To improve health care for older persons, we need to learn more about ageing, e.g. identify protective factors and early markers for diseases. The Gothenburg H70 Birth Cohort Studies (the H70 studies) are multidisciplinary epidemiological studies examining representative birth cohorts of older populations in Gothenburg, Sweden. So far, six birth cohorts of 70-year-olds have been examined over time, and examinations have been virtually identical between studies. This paper describes the study procedures for the baseline examination of the Birth cohort 1944, conducted in 2014-16. In this study, all men and women born 1944 on specific dates, and registered as residents in Gothenburg, were eligible for participation (n=1839). A total of 1203 (response rate 72.2%; 559 men and 644 women; mean age 70.5years) agreed to participate in the study. The study comprised sampling of blood and cerebrospinal fluid, psychiatric, cognitive, and physical health examinations, examinations of genetics and family history, use of medications, social factors, functional ability and disability, physical fitness and activity, body composition, lung function, audiological and ophthalmological examinations, diet, brain imaging, as well as a close informant interview, and qualitative studies. As in previous examinations, data collection serves as a basis for future longitudinal follow-up examinations. The research gained from the H70 studies has clinical relevance in relation to prevention, early diagnosis, clinical course, experience of illness, understanding pathogenesis and prognosis. Results will increase our understanding of ageing and inform service development, which may lead to enhanced quality of care for older persons.
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| 3. |
- Bindler, Richard, 1963-, et al.
(författare)
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Reshaping the landscape: mining, metallurgy and a millennium of environmental changes in south-central Sweden
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Before the recognition of emerging environmental issues during the 20th century such as acid rain, mercury pollution, climate change and biodiversity loss, human activities had already significantly altered landscapes around the globe. As elsewhere in Europe, the introduction of agriculture into Sweden during the Bronze and Iron Ages led to changes in forest cover, especially in southern areas, but also more limited impacts in central and northern Sweden along river valleys and coastal areas. In central Sweden the rise and rapid spread of ore mining and metallurgy from the 12th and especially 13th century initiated a widespread reshaping of the landscape named after its mining heritage –Bergslagen (mining laws). This mineral rich 89,000 km2 region encompasses ~5000 metallurgical sites (furnaces, smelters, foundries, forges) and ~10000 mines registered in the Swedish National Antiquities Board’s database.Analyses of >30 lake-sediment records using a combination of geochemical, diatom and pollen analyses, in combination with archaeological and historical records and toponyms, add important details to the early, poorly documented history of mining/metallurgy as well as provide insights into some of the environmental impacts across this large landscape. These impacts included damming of lakes and regulation of watercourses for waterpower, increase in erosion, emission of metals to surface waters and the atmosphere (and leaching from slag piles), decrease in forest cover and changes in water quality. The discontinuous appearance of pollen from cultivated plants (cereals) indicates some limited settlement before the 12th century, but the regular occurrence thereafter of cereal pollen together with a sharp increase in charcoal particles and geochemical evidence of mining/metallurgical activities, indicates mining/metallurgy was a driving force for settlement. Decline in forest cover was gradual from the 13th century, but was more significant from the late 16th century when iron and copper production increased exponentially. The increased demand for charcoal and increased agriculture, including an expansion of summer forest farms, contributed to a reduction in inferred forest cover to 40–80% – as compared to pre-anthropogenic (≤2000 BP) values of 84–95%. From the 16th century charcoal became the limiting resource within Bergslagen and metallurgy expanded to regions adjoining Bergslagen, contributing to a more widespread decline in forest cover also beyond the Bergslagen landscape.In association with the increase in land-use activities and resulting changes in vegetation cover, there was a decline (20–50%) in spectrally inferred lake-water total organic carbon, which we hypothesize resulted from a decreased pool of labile soil carbon. In some lakes closely connected with blast furnaces, where the peasant-miners also lived and farmed, there was an increase in diatom-inferred lake-water pH – as observed previously in SW Sweden in association with Iron Age land use. Only in a suite of lakes in close proximity to the smelting of copper sulfide ores in the surroundings of Falun was there evidence for pre-20th century acidification.While current rates of environmental change may be unprecedented, they build on an already modified landscape. Because pre-industrial conditions, i.e., pre-19th century, are often used as a reference level the scale of current changes may underestimate the full extent of ecosystem and environmental impacts.
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| 4. |
- Capo, Eric, et al.
(författare)
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How Does Environmental Inter-annual Variability Shape Aquatic Microbial Communities? : A 40-Year Annual Record of Sedimentary DNA From a Boreal Lake (Nylandssjon, Sweden)
- 2019
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Ingår i: Frontiers in Ecology and Evolution. - : Frontiers Media S.A.. - 2296-701X. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- To assess the sensitivity of lakes to anthropogenically-driven environmental changes (e.g., nutrient supply, climate change), it is necessary to first isolate the effects of between-year variability in weather conditions. This variability can strongly impact a lake's biological community especially in boreal and arctic areas where snow phenology play an important role in controlling the input of terrestrial matter to the lake. Identifying the importance of this inherent variability is difficult without time series that span at least several decades. Here, we applied a molecular approach (metabarcoding on eukaryotic 18S rRNA genes and qPCR on cyanobacterial 16S rRNA genes) to sedimentary DNA (sed-DNA) to unravel the annual variability of microbial community in 40 years' sediment record from the boreal lake Nylandssjon which preserve annually-laminated sediments. Our comparison between seasonal meteorological data, sediment inorganic geochemistry (X-ray fluorescence analyses) and organic biomarkers (pyrolysis-gas chromatography/mass spectrometry analyses), demonstrated that inter-annual variability strongly influence the sediment composition in Nylandssjon. Spring temperature, snow and ice phenology (e.g., the percentage of snow loss in spring, the timing of lake ice-off) were identified as important drivers for the inputs of terrestrial material to the lake, and were therefore also important for shaping the aquatic biological community. Main changes were detected in the late-80s/mid-90s and mid-2000s associated with increases in algal productivity, in total richness of the protistan community and in relative abundances of Chlorophyta, Dinophyceae as well as Cyanobacteria abundance. These changes could be linked to a decline in terrestrial inputs to the lake during the snow melt and run-off period, which in turn was driven by warmer winter temperatures. Even if our data shows that meteorological factors do affect the sediment composition and microbial communities, they only explain part of the variability. This is most likely a consequence of the high inter-annual variability in abiotic and biotic parameters highlighting the difficulty to draw firm conclusions concerning drivers of biological changes at an annual or sub-annual resolution even with the 40-year varved sediment record from Nylandssjon. Hence, it is necessary to have an even longer time perspective in order to reveal the full implications of climate change.
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| 5. |
- Capo, Eric, et al.
(författare)
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Lake sedimentary dna research on past terrestrial and aquatic biodiversity: Overview and recommendations
- 2021
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Ingår i: Quaternary. - : MDPI. - 2571-550X. ; 4:1
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Forskningsöversikt (refereegranskat)abstract
- The use of lake sedimentary DNA to track the long-term changes in both terrestrial and aquatic biota is a rapidly advancing field in paleoecological research. Although largely applied nowadays, knowledge gaps remain in this field and there is therefore still research to be conducted to ensure the reliability of the sedimentary DNA signal. Building on the most recent literature and seven original case studies, we synthesize the state-of-the-art analytical procedures for effective sampling, extraction, amplification, quantification and/or generation of DNA inventories from sedimentary ancient DNA (sedaDNA) via high-throughput sequencing technologies. We provide recommendations based on current knowledge and best practises.
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| 6. |
- Capo, Eric, et al.
(författare)
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Landscape setting drives the microbial eukaryotic community structure in four Swedish mountain lakes over the holocene
- 2021
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Ingår i: Microorganisms. - : MDPI. - 2076-2607. ; 9:2
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Tidskriftsartikel (refereegranskat)abstract
- On the annual and interannual scales, lake microbial communities are known to be heavily influenced by environmental conditions both in the lake and in its terrestrial surroundings. How-ever, the influence of landscape setting and environmental change on shaping these communities over a longer (millennial) timescale is rarely studied. Here, we applied an 18S metabarcoding approach to DNA preserved in Holocene sediment records from two pairs of co‐located Swedish mountain lakes. Our data revealed that the microbial eukaryotic communities were strongly influenced by catchment characteristics rather than location. More precisely, the microbial communities from the two bedrock lakes were largely dominated by unclassified Alveolata, while the peatland lakes showed a more diverse microbial community, with Ciliophora, Chlorophyta and Chytrids among the more predominant groups. Furthermore, for the two bedrock‐dominated lakes—where the oldest DNA samples are dated to only a few hundred years after the lake formation—certain Alveolata, Chlorophytes, Stramenopiles and Rhizaria taxa were found prevalent throughout all the sediment profiles. Our work highlights the importance of species sorting due to landscape setting and the persistence of microbial eukaryotic diversity over millennial timescales in shaping modern lake microbial communities.
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| 7. |
- Gälman, Veronika, 1969-, et al.
(författare)
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The role of iron and sulfur in the visual appearance of lake sediment varves
- 2009
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Ingår i: Journal of Paleolimnology. - : Springer Netherlands. - 0921-2728 .- 1573-0417. ; 42:1, s. 141-153
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Tidskriftsartikel (refereegranskat)abstract
- Easily discernible sediment varves (annual laminations) may be formed in temperate zone lakes, and reflect seasonal changes in the composition of the accumulating material derived from the lake and its catchment (minerogenic and organic material). The appearance of varves may also be influenced by chemical processes. We assessed the role of iron (Fe) and sulfur (S) in the appearance of varves in sediments from Lake Nylandssjön in northern Sweden. We surveyed Fe in the lake water and established whether there is internal transport of Fe within the sediment. We used a unique collection of seven stored freeze cores of varved sediment from the lake, collected from 1979 to 2004. This suite of cores made it possible to follow long-term changes in Fe and S in the sediment caused by processes that occur in the lake bottom when the sediment is ageing. We compared Fe and S concentrations using X-ray fluorescence spectroscopy (XRF) in specific years in the different cores. No diagenetic front was found in the sediment and the data do not suggest that there is substantial vertical transport of Fe and S in the sediment. We also modeled Fe and S based on thermodynamic, limnological, and sediment data from the lake. The model was limited to the five components H+, e-, Fe3+, SO42-, H2CO3 and included the formation of solid phases such as Fe(OH)3 (amorphous), FeOOH (aged, microcrystalline), FeS and FeCO3. Modeling showed that there are pe (redox) ranges within which either FeS or Fe(OH)3/FeOOH is the only solid phase present and there are pe ranges within which the two solid phases co-exist, which supports the hypothesis that blackish and grey-brownish layers that occur in the varves were formed at the time of deposition. This creates new possibilities for deciphering high-temporal-resolution environmental information from varves.
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| 8. |
- 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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| 9. |
- Lindborg, Tobias, et al.
(författare)
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A carbon mass-balance budget for a periglacial catchment in West Greenland : Linking the terrestrial and aquatic systems
- 2020
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Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 711
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Tidskriftsartikel (refereegranskat)abstract
- Climate change is predicted to have far reaching consequences for the mobility of carbon in arctic landscapes. On a regional scale, carbon cycling is highly dependent on interactions between terrestrial and aquatic parts of a catchment. Despite this, studies that integrate the terrestrial and aquatic systems and study entire catchments using site-specific data are rare. In this work, we use data partly published by Lindborg et al. (2016a) to calculate a whole-catchment carbon mass-balance budget for a periglacial catchment in West Greenland. Our budget shows that terrestrial net primary production is the main input of carbon (99% of input), and that most carbon leaves the system through soil respiration (90% of total export/storage). The largest carbon pools are active layer soils (53% of total carbon stock or 13 kg C m (2)), permafrost soils (30% of total carbon stock or 7.6 kg C m (2)) and lake sediments (13% of total carbon stock or 10 kg C m (2)). Hydrological transport of carbon from the terrestrial to aquatic system is lower than in wetter climates, but the annual input of 4100 kg C yr (1) (or 3.5 g C m (2) yr (1)) that enters the lake via runoff is still three times larger than the eolian input of terrestrial carbon. Due to the dry conditions, the hydrological export of carbon from the catchment is limited (5% of aquatic export/storage or 0.1% of total export/storage). Instead, CO2 evasion from the lake surface and sediment burial accounts for 57% and 38% of aquatic export/storage, respectively (or 0.8% and 0.5% of total export/storage), and Two-Boat Lake acts as a net source of carbon to the atmosphere. The limited export of carbon to downstream water bodies make our study system different from wetter arctic environments, where hydrological transport is an important export pathway for carbon.
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| 10. |
- Myrstener, Erik, et al.
(författare)
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Environmental footprint of small-scale, historical mining and metallurgy in the Swedish boreal forest landscape : The Moshyttan blast furnace as microcosm
- 2019
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Ingår i: The Holocene. - : Sage Publications. - 0959-6836 .- 1477-0911. ; 29:4, s. 578-591
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Tidskriftsartikel (refereegranskat)abstract
- The history of mining and smelting and the associated pollution have been documented using lake sediments for decades, but the broader ecological implications are not well studied. We analyzed sediment profiles covering the past similar to 10,000 years from three lakes associated with an iron blast furnace in central Sweden, as an example of the many small-scale furnaces with historical roots in the medieval period. With a focus on long-term lake-water quality, we analyzed multiple proxies including geochemistry, pollen and charcoal, diatom composition and inferred pH, biogenic silica (bSi), visible near-infrared spectroscopy (VNIRS)-inferred lake-water total organic carbon (LW-TOC), and VNIRS-inferred sediment chlorophyll (sed-Chl). All three lakes had stable conditions during the middle Holocene (similar to 5000 BCE to 1110 CE) typical of oligo-dystrophic lakes: pH 5.4-5.6, LW-TOC 15-18 mg L-1. The most important diatom taxa include, for example, Aulacoseira scalaris, Brachysira neoexilis, and Frustulia saxonica. From similar to 1150 CE, decreases in LW-TOC, bSi, and sed-Chl in all three lakes coincide with a suite of proxies indicating disturbance associated with local, small-scale agriculture, and the more widespread use of the landscape in the past (e.g. forest grazing, charcoal production). Most important was a decline in LW-TOC by 30-50% in the three lakes prior to the 20th century. In addition, the one lake (Fickeln) downstream of the smelter and main areas of cultivation experienced a shift in diatom composition (mainly increasing Asterionella formosa) and a 0.6 pH increase coinciding with increasing cereal pollen and signs of blast furnace activity. The pH did not change in the other two lakes in response to disturbance; however, these lakes show a slight increase (0.3-0.5 pH units) because of modern liming. LW-TOC has returned to background levels in the downstream lake and remains lower in the other two.
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