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Hansson, Sophia
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Hansson, S. V., Kaste, J. M., Chen, K. & Bindler, R. (2014). Beryllium-7 as a natural tracer for short-term downwash in peat. Biogeochemistry, 119(1-3), 329-339
Öppna denna publikation i ny flik eller fönster >>Beryllium-7 as a natural tracer for short-term downwash in peat
2014 (Engelska)Ingår i: Biogeochemistry, ISSN 0168-2563, E-ISSN 1573-515X, Vol. 119, nr 1-3, s. 329-339Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Several factors can affect the integrity of natural archives such as peat records, e.g., decomposition and nutrient cycling, and it has also been hypothesized that some rapid downward transport of atmospherically derived elements may occur. We test this hypothesis by analyzing the short-lived, natural tracer beryllium-7 (tA1/2A = 53.4 days) in five cores from two peatlands. In triplicate hummock cores from a raised bog in southern Sweden, Be-7 could be measured to 20, 18 and 8 cm depth, and in a nutrient-poor mire in northern Sweden to a depth of 16 cm in a Sphagnum lawn core, but only 4 cm in the dominant, more-decomposed fen peat, indicating some spatial variability both within and between sites. Total Be-7 inventories were 320-450 Bq m(-2) in the bog, and 150 Bq m(-2) (lawn) and 240 Bq m(-2) (fen peat) in the mire. 25-79 % of the total inventory of Be-7 was located in the upper 2-cm layer. To further test downwashing, in the laboratory we applied a CuBr-solution to two cores and a Cu-solution to one core taken from the mire Sphagnum lawn, all with low water table conditions. About 50 % of the added Cu and similar to 35 % of the added Br were retained in the surface (2 cm) layer; 1-3 % of the Cu was found at 8-12 cm depth and similar to 1 % of the Br was measured in the lowest level (20-22 cm). Based on our novel approach using Be-7 and experimental work we show that short-term downwashing can occur in peatlands and we suggest the depth of this will depend on the properties of the peat, e.g., bulk density and decomposition, as well as hydrology.

Nyckelord
Beryllium, Downwash, Geochemistry, Peat
Nationell ämneskategori
Geokemi
Identifikatorer
urn:nbn:se:umu:diva-84158 (URN)10.1007/s10533-014-9969-y (DOI)000336028400021 ()
Tillgänglig från: 2013-12-16 Skapad: 2013-12-16 Senast uppdaterad: 2018-06-08Bibliografiskt granskad
Hansson, S. V., Kaste, J. M., Olid, C. & Bindler, R. (2014). Incorporation of radiometric tracers in peat and implications for estimating accumulation rates. Science of the Total Environment, 493, 170-177
Öppna denna publikation i ny flik eller fönster >>Incorporation of radiometric tracers in peat and implications for estimating accumulation rates
2014 (Engelska)Ingår i: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 493, s. 170-177Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Accurate dating of peat accumulation is essential for quantitatively reconstructing past changes in atmospheric metal deposition and carbon burial. By analyzing fallout radionuclides Pb-210, Cs-137, Am-241, and Be-7, and total Pb and Hg in 5 cores from two Swedish peatlands we addressed the consequence of estimating accumulation rates due to downwashing of atmospherically supplied elements within peat. The detection of Be-7 down to 18-20 cm for some cores, and the broad vertical distribution of Am-241 without a well-defined peak, suggest some downward transport by percolating rainwater and smearing of atmospherically deposited elements in the uppermost peat layers. Application of the CRS age-depth model leads to unrealistic peat mass accumulation rates (400-600 g m(-2) yr(-1)), and inaccurate estimates of past Pb and Hg deposition rates and trends, based on comparisons to deposition monitoring data (forest moss biomonitoring and wet deposition). After applying a newly proposed IP-CRS model that assumes a potential downward transport of Pb-210 through the uppermost peat layers, recent peat accumulation rates (200-300 g m(-2) yr(-1)) comparable to published values were obtained. Furthermore, the rates and temporal trends in Pb and Hg accumulation correspond more closely to monitoring data, although some off-set is still evident. We suggest that downwashing can be successfully traced using Be-7, and if this information is incorporated into age-depth models, better calibration of peat records with monitoring data and better quantitative estimates of peat accumulation and past deposition are possible, although more work is needed to characterize how downwashing may vary between seasons or years.

Ort, förlag, år, upplaga, sidor
Elsevier, 2014
Nyckelord
Beryllium, Downwash, Lead, Mercury, Peat accumulation
Nationell ämneskategori
Geokemi
Identifikatorer
urn:nbn:se:umu:diva-84160 (URN)10.1016/j.scitotenv.2014.05.088 (DOI)000340312000019 ()24946030 (PubMedID)
Tillgänglig från: 2013-12-16 Skapad: 2013-12-16 Senast uppdaterad: 2018-06-08Bibliografiskt granskad
Hansson, S. V., Rydberg, J., Kylander, M., Gallagher, K. & Bindler, R. (2013). Evaluating paleoproxies for peat decomposition and their relationship to peat geochemistry. The Holocene, 23(12), 1666-1667
Öppna denna publikation i ny flik eller fönster >>Evaluating paleoproxies for peat decomposition and their relationship to peat geochemistry
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2013 (Engelska)Ingår i: The Holocene, ISSN 0959-6836, E-ISSN 1477-0911, Vol. 23, nr 12, s. 1666-1667Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

The past decade has seen a rapid increase in interest in the biogeochemical record preserved in peat, particularly as it relates to carbon dynamics and environmental change. Importantly, recent studies show that carbon dynamics, that is, organic matter decomposition, can influence the record of atmospherically derived elements such as halogens and mercury. Most commonly, bulk density, light transmission, or carbon/nitrogen (C/N) ratios are used as a proxy to qualitatively infer the degree of decomposition in peat, but do these three proxies reflect the same patterns? Furthermore, how do each of these proxies relate to other geochemical data? To address these questions, we analyzed bulk density, light transmission, and C/N ratios, as well as multielement geochemistry (wavelength-dispersive x-ray fluorescence (WD-XRF)), in three hummock cores (70 cm in length, c. 500 years) from an ombrotrophic Swedish bog. To compare the proxies, we applied principal component analysis (PCA) to identify how the proxies relate to and interact with the geochemical matrix. This was coupled with changepoint modeling to identify and compare statistically significant changes for each proxy. Our results show differences between the proxies within and between cores, indicating each responds to a different part of the decomposition process. This is supported by the PCA, where the three proxies fall on different principal components. Changepoint analysis also showed that the inferred number of changepoints and their depths vary for each proxy and core. This suggests that decomposition is not fully captured by any one of these commonly used proxies, and thus, more than one proxy should be included.

Ort, förlag, år, upplaga, sidor
Sage Publications, 2013
Nyckelord
bulk density, C, N ratio, decomposition, humification, light transmission, peat
Nationell ämneskategori
Geokemi
Identifikatorer
urn:nbn:se:umu:diva-84156 (URN)10.1177/0959683613508160 (DOI)000327472500002 ()
Forskningsfinansiär
Vetenskapsrådet
Tillgänglig från: 2013-12-16 Skapad: 2013-12-16 Senast uppdaterad: 2018-06-08Bibliografiskt granskad
Hansson, S. V. (2013). Incorporation and preservation of geochemical fingerprints in peat archives. (Doctoral dissertation). Umeå: Umeå Universitet
Öppna denna publikation i ny flik eller fönster >>Incorporation and preservation of geochemical fingerprints in peat archives
2013 (Engelska)Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
Abstract [en]

The present status of the environment, including environmental problems such as heavy metal accumulation in aquatic and terrestrial ecosystems, is in part the consequence of long-term changes. Cores from peatlands and other natural archives provide us with the potential to study aspects of the atmospheric cycling of elements, such as metal pollutants, on timescales much longer than the decade or two available to us with atmospheric deposition monitoring programs. The past decade especially has seen a rapid increase in interest in the biogeochemical record preserved in peat, particularly as it relates to environmental changes (e.g. climate and pollution). Importantly, recent studies have shown that carbon dynamics, i.e., organic matter decomposition, may influence the record of atmospherically derived elements such as halogens and mercury. Other studies have shown that under certain conditions some downward movement of atmospherically deposited elements may also occur, which adds complexity to establishing reliable chronologies as well as inherent problems of estimating accurate accumulation rates of peat and past metal deposition. Thus, we still lack a complete understanding of the basic biogeochemical processes and their effects on trace element distributions. While many studies have validated the general temporal patterns of peat records, there has been a limited critical examination of accumulation records in quantitative terms. To be certain that we extract not only a qualitative record from peat, it is important that we establish a quantitative link between the archive and the few to several decades of data that are available from contemporary monitoring and research. The main objective of this doctoral thesis was to focus on improving the link between the long-term paleorecord and the contemporary monitoring data available from biomonitoring and direct deposition observations. The main research questions have therefore been: Are peat archives an absolute or relative record? And how are geochemical signals, including dating, incorporated in the peat archive? What temporal resolution is realistic to interpret by using peat cores?

Ort, förlag, år, upplaga, sidor
Umeå: Umeå Universitet, 2013. s. 36
Nyckelord
Peat, Beryllium, bulk density, C/N-ratio, decomposition, deposition, downwash, elemental mobility, geochemistry, humification, lead, light transmission, mercury, peat accumulation, precipitation
Nationell ämneskategori
Miljövetenskap
Forskningsämne
biologi, miljövetenskap
Identifikatorer
urn:nbn:se:umu:diva-84161 (URN)978-91-7459-779-0 (ISBN)
Disputation
2014-01-24, KB3A9, KBC, Umeå University, Umeå, 10:00 (Engelska)
Opponent
Handledare
Tillgänglig från: 2013-12-17 Skapad: 2013-12-16 Senast uppdaterad: 2018-06-08Bibliografiskt granskad
Bindler, R., Yu, R., Hansson, S., Classen, N. & Karlsson, J. (2012). Mining, Metallurgy and the Historical Origin of Mercury Pollution in Lakes and Watercourses in Central Sweden. Environmental Science and Technology, 46(15), 7984-7991
Öppna denna publikation i ny flik eller fönster >>Mining, Metallurgy and the Historical Origin of Mercury Pollution in Lakes and Watercourses in Central Sweden
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2012 (Engelska)Ingår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 46, nr 15, s. 7984-7991Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

In Central Sweden an estimated 80% of the lakes contain fish exceeding health guidelines for mercury. This area overlaps extensively with the Bergslagen ore region, where intensive mining of iron ores and massive sulfide ores occurred over the past millennium. Although only a few mines still operate today, thousands of mineral occurrences and mining sites are documented in the region. Here, we present data on long-term mercury pollution in 16 sediment records from 15 lakes, which indicate that direct release of mercury to lakes and watercourses was already significant prior to industrialization (<AD 1800). Thirteen of our lakes show increases in mercury from 3-fold-equivalent to the enrichment factor in many remote lakes today-to as much as 60-fold already during the period AD 1500-1800, with the highest values in the three lakes most closely connected to major mines. Although the timing and magnitude of the historical increases in mercury are heterogeneous among lakes, the data provide unambiguous evidence for an incidental release of mercury along with other mining metals to lakes and watercourses, which suggests that the present-day problem of elevated mercury concentrations in the Bergslagen region can trace its roots back to historical mining.

Ort, förlag, år, upplaga, sidor
American Chemical Society (ACS), 2012
Nationell ämneskategori
Ekologi Annan geovetenskap och miljövetenskap
Identifikatorer
urn:nbn:se:umu:diva-66459 (URN)10.1021/es300789q (DOI)000307199800012 ()
Tillgänglig från: 2013-02-20 Skapad: 2013-02-20 Senast uppdaterad: 2018-12-03Bibliografiskt granskad
Bindler, R., Segerström, U., Pettersson-Jensen, I.-M., Berg, A., Hansson, S., Holmström, H., . . . Renberg, I. (2011). Early medieval origins of iron mining and settlement in central Sweden: multiproxy analysis of sediment and peat records from the Norberg mining district. Journal of Archaeological Science, 38(2), 291-300
Öppna denna publikation i ny flik eller fönster >>Early medieval origins of iron mining and settlement in central Sweden: multiproxy analysis of sediment and peat records from the Norberg mining district
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2011 (Engelska)Ingår i: Journal of Archaeological Science, ISSN 0305-4403, E-ISSN 1095-9238, Vol. 38, nr 2, s. 291-300Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

The historical Norberg mining district in central Sweden with its shallow, easily accessible iron ores figures prominently in the earliest documents from the 14th century concerning mining or metallurgy. This 1000-km2 district is considered to be one of the first areas in Sweden exploited for iron ores and, in fact, Europe’s oldest known blast furnace, Lapphyttan, is located in the Norberg district about 10 km from the mines in the village of Norberg (Norbergsby). Earlier archaeological excavations suggest the furnace was in operation as early as the 11th or 12th century (870 and 930 14C yr BP), and a number of other sites in the district have been dated to the 13th–15th centuries. Here, we have analyzed two lake sediment records (Kalven and Noren) from the village of Norberg and a peat record from Lapphyttan. The Lapphyttan peat record was radiocarbon dated, whereas the sediment from Kalven is annually laminated, which provides a fairly precise chronology. Our pollen data indicate that land use in the area began gradually as forest grazing by at least c. AD 1050, with indications of more widespread forest disturbance and cultivation from c. 1180 at Lapphyttan and 1250 at Kalven. Based on 206Pb/207Pb isotope ratios in Kalven’s varved sediment record, there is an indication of mining or metallurgy in the area c. 960, but likely not in immediate connection to our sites. Evidence of mining and metallurgy increases gradually from c. 1180 when there is a decline in 206Pb/207Pb ratios and an increase in charcoal particles at Lapphyttan, followed by increasing inputs of lithogenic elements in Noren’s sediment record indicating soil disturbance, which we attribute to the onset of mining the iron ore bodies surrounding Noren. From AD 1295 onwards evidence of mining and metallurgy are ubiquitous, and activities accelerate especially during the late 15th century; the maximum influence of Bergslagen ore lead (i.e., the minimum in 206Pb/207Pb isotope ratios) in both Kalven and Noren occurs c. 1490–1500, when also varve properties change in Kalven and in Noren sharp increases occur in the concentrations of a range of other ore-related metals (e.g., arsenic, cadmium, copper, iron, lead, mercury and zinc). From the 15th century onwards mining and metallurgy are the dominant feature of the sediment records.

Nyckelord
Iron mining, lake sediment, peat, geochemistry, pollen
Identifikatorer
urn:nbn:se:umu:diva-38214 (URN)10.1016/j.jas.2010.09.004 (DOI)
Tillgänglig från: 2010-11-30 Skapad: 2010-11-30 Senast uppdaterad: 2018-06-08Bibliografiskt granskad
Bindler, R., Myrstener, E., Liu, E., Bigler, C., Hansson, S., Meyer-Jacob, C., . . . Rydberg, J.Reshaping the landscape: mining, metallurgy and a millennium of environmental changes in south-central Sweden.
Öppna denna publikation i ny flik eller fönster >>Reshaping the landscape: mining, metallurgy and a millennium of environmental changes in south-central Sweden
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(Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
Abstract [en]

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.

Nationell ämneskategori
Miljövetenskap
Forskningsämne
miljövetenskap
Identifikatorer
urn:nbn:se:umu:diva-163434 (URN)
Tillgänglig från: 2019-09-19 Skapad: 2019-09-19 Senast uppdaterad: 2019-09-19
Lundin, E., Klaminder, J., Bastviken, D., Olid, C., Hansson, S. & Karlsson, J. Strong climate impact on the carbon emission – burial balance inhigh latitude lakes.
Öppna denna publikation i ny flik eller fönster >>Strong climate impact on the carbon emission – burial balance inhigh latitude lakes
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(Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
Abstract [en]

Lakes play an important role in the global carbon (C) cycle by burying C in sediments and emitting CO2 and CH4 to the atmosphere. The strengths of these fundamentally different pathways are critical for quantifying effects of lakes upon the climate system. In this study, based on new high-resolution estimates in combination with literature data, we show a generally ten times higher emission:burial ratio in boreal compared to subarctic-arctic lakes. These results suggest a major bioclimatic impact on C cycling in lakes, as lakes in warmer boreal regions emit more and store relatively less C than lakes in colder arctic regions. Thus, our results reveal a previously unforeseen longterm climate feedback: if predictions of the northward expansion of the boreal biome are correct, C emissions of high latitude lakes may increase four-fold, corresponding to 14% of present global lake C evasion to the atmosphere. Such effects are of major importance for understanding feedbacks of climate warming on the continental source-sink function at high latitudes

 

 

Nationell ämneskategori
Multidisciplinär geovetenskap
Forskningsämne
geovetenskap med inriktning mot miljöanalys; limnologi
Identifikatorer
urn:nbn:se:umu:diva-84499 (URN)
Forskningsfinansiär
Vetenskapsrådet, 621-385 2008-4390
Anmärkning

Submitted

Tillgänglig från: 2014-01-08 Skapad: 2014-01-08 Senast uppdaterad: 2018-06-08
Hansson, S. V., Tolu, J. & Bindler, R. Testing the downwash of atmospherically deposited metals in peat and the influence of rainfall intensity.
Öppna denna publikation i ny flik eller fönster >>Testing the downwash of atmospherically deposited metals in peat and the influence of rainfall intensity
(Engelska)Artikel i tidskrift (Refereegranskat) Submitted
Nationell ämneskategori
Geokemi
Identifikatorer
urn:nbn:se:umu:diva-84159 (URN)
Tillgänglig från: 2013-12-16 Skapad: 2013-12-16 Senast uppdaterad: 2018-06-08Bibliografiskt granskad
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