| 1. |
- Akerblom, Staffan, et al.
(författare)
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Experimentally induced effects of heavy metal on microbial activity and community structure of forest mor layers
- 2007
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Ingår i: Biology and Fertility of Soils. - : Springer Science and Business Media LLC. - 0178-2762 .- 1432-0789. ; 44:1, s. 79-91
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Tidskriftsartikel (refereegranskat)abstract
- This study compared the toxic effects of adding chromium (Cr), zinc (Zn), lead (Pb), molybdenum (Mo), nickel (Ni), and cadmium (Cd) at three dose levels to mor layer samples in laboratory experiments. Microbial activity in the form of soil respiration was monitored for 64 days. At the end of the experimental period, the composition of the soil microbial community structure was analysed by phospholipid fatty acid (PLFA) analysis. The metals added induced changes in the microbial community structure and affected respiration negatively, indicating toxicity. The microbial community structure (principal component analysis of the PLFA pattern) for all metals was significantly related to microbial activity (cumulative respiration), indicating intimate links between microbial community structure and activity. The most striking result in this study was that the shift in the microbial community because of metal stress was similar for all metals. Thus, the PLFA i16:0 increased most in relative abundance in metal-polluted soils, followed by other PLFAs indicative of Gram-positive bacteria (10Me16:0, 10Me17:0, 10Me18:0, a17:0 and br18:0). The PLFA 16:1 omega 5 was consistently negatively affected by metal stress, as were the PLFAs 18:1, 18:1 omega 7 and 19:1a. However, a significant separation between Cr- and Cd-polluted soils was observed in the response of the PLFA cy19:0, which decreased in abundance with Cr stress, and increased with Cd stress. Furthermore, the PLFA 18:2w6, indicating fungi, only increased with Cr and Zn stress. The effective doses of the metals, ranked with regard to background metal concentrations, decreased in the order: Zn > Cr > Pb > Mo > Ni > Cd. We concluded that interpretation of results of microbial activity from experiments of metal toxicity should include microbial structural patterns and background metal concentrations.
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| 2. |
- Bringmark, Ewa, et al.
(författare)
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Long-term monitoring of scots pine litter decomposition rates throughout sweden indicates formation of a more recalcitrant litter in the south
- 2011
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Ingår i: Ambio. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 40:8, s. 878-890
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Tidskriftsartikel (refereegranskat)abstract
- Decomposition studies were carried out at sites throughout Sweden, including the four Integrated Monitoring sites. Scots pine needle litterbag weight loss measurements over 3 or 5 years were determined at 26 sites and repeated up to 27 times, depending on the site. Humus layer respiration rates were determined for 20 sites in 1987-1989 and repeated in 2007-2008. Partial Least Squares (PLS) regression was used to elucidate the relative importance of climatic and soil factors. Annual needle weight losses decreased only slowly (20-10%) over 3-5 years for all northern (> 60A degrees N) sites but decreased sharply from 30 to 10% in the third year in southern (< 60A degrees N) sites. Respiration rates of southern sites were less (40% on average) than those of northern sites. Humus layer N was positively correlated to needle weight loss during the first and the second years, but negatively correlated in the third year and to respiration rates. The results indicated that litter formed in southern Sweden became more recalcitrant in later stages of decomposition compared to litter produced in northern Sweden.
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| 3. |
- Bishop, Kevin, et al.
(författare)
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The Effects of Forestry on Hg Bioaccumulation in Nemoral/Boreal Waters and Recommendations for Good Silvicultural Practice
- 2009
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Ingår i: Ambio. - : Royal Swedish Academy of Sciences. - 0044-7447 .- 1654-7209. ; 38:7, s. 373-380
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Tidskriftsartikel (refereegranskat)abstract
- Mercury (Hg) levels are alarmingly high in fish from lakes across Fennoscandia and northern North America. The few published studies on the ways in which silviculture practices influence this problem indicate that forest operations increase Hg in downstream aquatic ecosystems. From these studies, we estimate that between one-tenth and one-quarter of the Hg in the fish of high-latitude, managed forest landscapes can be attributed to harvesting. Forestry, however, did not create the elevated Hg levels in the soils, and waterborne Hg/MeHg concentrations downstream from harvested areas are similar to those from wetlands. Given the current understanding of the way in which silviculture impacts Hg cycling, most of the recommendations for good forest practice in Sweden appear to be appropriate for high-latitude regions, e.g., leaving riparian buffer zones, as well as reducing disturbance at stream crossings and in moist areas. The recommendation to restore wetlands and reduce drainage, however, will likely increase Hg/MeHg loadings to aquatic ecosystems
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| 4. |
- Bringmark, Lage, et al.
(författare)
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Heavy metal budgets and critical loads at ICP Integrated Monitoring sites
- 2009
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Ingår i: 18th Annual Report 2009 : Convention on Long-range Transboundary Air Pollution : International Cooperative Programme on Integrated Monitoring of Air Pollution Effects on Ecosystems. ; :23, s. 64-70
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 5. |
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| 6. |
- Bringmark, Lage, et al.
(författare)
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Trace metal budgets for forested catchments in Europe – Pb, Cd, Hg, Cu and Zn
- 2013
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Ingår i: Water, Air, and Soil Pollution. - : Springer Science and Business Media LLC. - 0049-6979 .- 1573-2932. ; 224
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Tidskriftsartikel (refereegranskat)abstract
- Input/output budgets for cadmium (Cd), lead (Pb) and mercury (Hg) in the years 1997 monitored and determined for 14 small forest-covered catchments across Europe as part of the Integrated Monitoring program on the effects of long-range pollutants on ecosystems. Metal inputs were considered to derive from bulk deposition, throughfall and litterfall. Outputs were estimated from run-off values. Litterfall plus throughfall was taken as a measure of the total deposition of Pb and Hg (wet+dry) on the basis of evidence suggesting that, for these metals, internal circulation is negligible. The same is not true for Cd. Excluding a few sites with high discharge, between 74 and 94 % of the input Pb was retained within the catchments; significant Cd retention was also observed. High losses of Pb (>1.4 mgm (>0.15 mgm Central European sites with high water discharge. All other sites had outputs below or equal to 0.36 and 0.06 mgm Almost complete retention of Hg, 86 was reported in the Swedish sites. These high levels of metal retention were maintained even in the face of recent dramatic reductions in pollutant loads.–2011 were−2year−1) and Cd−2year−1) were observed in two mountainous−2year−1, respectively, for the two metals.–99 % of input,
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| 7. |
- Futter, Martyn, et al.
(författare)
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Simulating dissolved organic carbon dynamics at the Swedish Integrated Monitoring sites with the Integrated Catchments Model for Carbon, INCA-C
- 2011
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Ingår i: AMBIO: A Journal of the Human Environment. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 40, s. 906-919
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Tidskriftsartikel (refereegranskat)abstract
- Surface water concentrations of dissolved organic carbon ([DOC]) are changing throughout the northern hemisphere due to changes in climate, land use and acid deposition. However, the relative importance of these drivers is unclear. Here, we use the Integrated Catchments model for Carbon (INCA-C) to simulate long-term (1996-2008) streamwater [DOC] at the four Swedish integrated monitoring (IM) sites. These are unmanaged headwater catchments with old-growth forests and no major changes in land use. Daily, seasonal and long-term variations in streamwater [DOC] driven by runoff, seasonal temperature and atmospheric sulfate (SO4 2-) deposition were observed at all sites. Using INCA-C, it was possible to reproduce observed patterns of variability in streamwater [DOC] at the four IM sites. Runoff was found to be the main short-term control on [DOC]. Seasonal patterns in [DOC] were controlled primarily by soil temperature. Measured SO4 2- deposition explained some of the long-term [DOC] variability at all sites.
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| 8. |
- Lundin, Lars, et al.
(författare)
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Report on national ICP IM activities in Sweden 2009-2011
- 2011
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Ingår i: 20th Annual Report 2011 : Convention on Long-range Transboundary Air Pollution : International Cooperative Programme on Integrated Monitoring of Air Pollution Effects on Ecosystems. - 9789521139086 ; :2011:18, s. 58-63
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 9. |
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| 10. |
- Lundin, Lars, et al.
(författare)
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Report on recent national ICP IM activities in Sweden 2012-2014
- 2014
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Ingår i: 23rd Annual Report : convention on Long-range Transboundary Air Pollution : international Cooperative Programme on Integrated Monitoring of Air Pollution Effects on Ecosystems. ; :23, s. 52-58
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 11. |
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| 12. |
- Löfgren, Stefan, et al.
(författare)
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Decreasing DOC trends in soil solution along the hillslopes at two IM sites in southern Sweden : Geochemical modeling of organic matter solubility during acidification recovery
- 2010
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 409:1, s. 201-210
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Tidskriftsartikel (refereegranskat)abstract
- Numerous studies report increased concentrations of dissolved organic carbon (DOC) during the last two decades in boreal lakes and streams in Europe and North America Recently a hypothesis was presented on how various spatial and temporal factors affect the DOC dynamics It was concluded that declining sulphur deposition and thereby increased DOC solubility is the most important driver for the long-term DOC concentration trends in surface waters If this recovery hypothesis is correct the DOC levels should increase both in the soil solution as well as in the surrounding surface waters as soil pH rises and the ionic strength declines due to the reduced input of SO42- ions In this project a geochemical model was set up to calculate the net humic charge and DOC solubility trends in soils during the period 1996-2007 at two integrated monitoring sites in southern Sweden showing clear signs of acidification recovery The Stockholm Humic Model was used to investigate whether the observed DOC solubility is related to the humic charge and to examine how pH and ionic strength influence it Soil water data from recharge and discharge areas covering both podzols and riparian soils were used The model exercise showed that the increased net charge following the pH increase was in many cases counteracted by a decreased ionic strength, which acted to decrease the net charge and hence the DOC solubility Thus the recovery from acidification does not necessarily have to generate increasing DOC trends in soil solution Depending on changes in pH ionic strength and soil Al pools the trends might be positive negative or indifferent Due to the high hydraulic connectivity with the streams the explanations to the DOC trends in surface waters should be searched for in discharge areas and peat lands.
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| 13. |
- Löfgren, Stefan; Lundin, Lars; Bringmark, Lage,
(författare)
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Flödesbanornas betydelse för utlakningen från avrinningsområdet
- 2007
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Transporten av ämnen från deposition, vittring och jonbyte till ytvattenbildning beror till stor del på vattenströmning och flödesvägar. För att förstå sambanden mellan tillförsel av ämnen och dessas betydelse för ytvattnens kvalité är de hydrologiska förhållandena avgörande. Syftet med undersökningarna är att få underlag för att optimera mätningarna inom IM-områdena baserat på identifiering av de mest relevanta flödesbanorna längs vattnets väg. Projektet är pågående inom IM programmet och resultat av tre års mätningar kan nu redovisas. Undersökningarna startade 2004 med instrumentering och inledande provtagning. Under 2005 och 2006 har ytterligare vatten- och markprovtagning genomförts. Den senaste vattenprovtagningen gjordes i november 2006. Inledande resultat visar på god överensstämmelse med de modeller som tagits fram för relationer mellan pH, TOC och aluminium. Betydelsen av dränerade marker och sådana bäcksträckor där organiska marktyper har mindre utbredning inverkar klart på ytvattenkemin. Det organiska materialet i bäcknära zon kan fungera som ett filter och lagra ämnen, som dock kan frigöras under särskilda episoder. IM programmet anpassas i riktning för att bättre fånga de mest relevanta marktyperna och flödesbanorna. Kunskapen bidrar i arbetet om luftföroreningarnas konsekvenser och ger potentiell input i kvalitetsarbetet inom Vattendirektivet.
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| 14. |
- Löfgren, Stefan, et al.
(författare)
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Recovery of Soil Water, Groundwater, and Streamwater From Acidification at the Swedish Integrated Monitoring Catchments
- 2011
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Ingår i: AMBIO: A Journal of the Human Environment. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 40, s. 836-856
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Tidskriftsartikel (refereegranskat)abstract
- Recovery from anthropogenic acidification in streams and lakes is well documented across the northern hemisphere. In this study, we use 1996–2009 data from the four Swedish Integrated Monitoring catchments to evaluate how the declining sulfur deposition has affected sulfate, pH, acid neutralizing capacity, ionic strength, aluminum, and dissolved organic carbon in soil water, groundwater and runoff. Differences in recovery rates between catch- ments, between recharge and discharge areas and between soil water and groundwater are assessed. At the IM sites, atmospheric deposition is the main human impact. The chemical trends were weakly correlated to the sulfur deposition decline. Other factors, such as marine influence and catchment features, seem to be as important. Except for pH and DOC, soil water and groundwater showed similar trends. Discharge areas acted as buffers, dampening the trends in streamwater. Further monitoring and modeling of these hydraulically active sites should be encouraged
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| 15. |
- Strengbom, Joachim, et al.
(författare)
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Working group report
- 2011
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Ingår i: Nitrogen deposition and Natura 2000: Science and Practice in determining Environmental Impact. - 9789186125233 ; , s. 128-135
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 16. |
- Åkerblom, Staffan, et al.
(författare)
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Organic matter control of mercury and lead toxicity in mor layers
- 2010
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Ingår i: Ecotoxicology and Environmental Safety. - : Elsevier BV. - 0147-6513 .- 1090-2414. ; 73, s. 924-931
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Tidskriftsartikel (refereegranskat)abstract
- This study evaluated the effect of organic matter composition on Hg and Pb toxicity for heterotrophic respiration in mor layers in long-term in vitro dose-response experiments. Pb proved to be a more potent toxin than Hg at comparable metal additions. The degree of litter decomposition and fragmentation and background Hg concentration levels were key factors determining metal toxicity. Higher sensitivity to metal additions in the fermentation layer than in litter and humification layers was corroborated. The role of organic matter composition was further examined in litter after structural disintegration by milling, which significantly increased the sensitivity of heterotrophic respiration to metal additions. A threshold value causing 5% reduction in heterotrophic respiration was estimated at 800 mu g Hg kg(-1). In boreal forests in the northern hemisphere, the mean regional Hg concentrations in mor layers amount to approximately half this threshold value. (C) 2009 Elsevier Inc. All rights reserved.
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| 17. |
- Åkerblom, Staffan, et al.
(författare)
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Partitioning of Hg between solid and dissolved organic matter in the humus layer of boreal forests
- 2008
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Ingår i: Water, Air and Soil Pollution. - : Springer Science and Business Media LLC. - 1573-2932 .- 0049-6979. ; 189:1-4, s. 239-252
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Tidskriftsartikel (refereegranskat)abstract
- The mobility of mercury (Hg) deposited on soils controls the concentration and toxicity of Hg within soils and in nearby streams and lakes, but has rarely been quantified under field conditions. We studied the in situ partitioning of Hg in the organic top layer (mor) of podsols at two boreal forest sites differing in Hg deposition and climatic regime (S. and N. Sweden, with pollution declining to the north). Soil solution leaching from the mor layer was repeatedly sampled using zero-tension lysimeters over 2 years, partly in parallel with tension lysimeters. Concentrations of Hg and dissolved organic carbon (DOC) were higher while pH was lower at the southern site (means +/- SD: Hg=44 +/- 15 ng L-1, DOC=63.0 +/- 31.3 mg L-1, pH=4.05 +/- 0.53) than at the northern site (Hg=22 +/- 6 ng L-1, DOC=41.8 +/- 12.1 mg L-1, pH=4.28 +/- 0.43). There was a positive correlation over time between dissolved Hg and DOC at both sites, even though the DOC concentration peaked during autumn at both sites, while the Hg concentration remained more constant. This correlation is consistent with the expected strong association of Hg with organic matter and supports the use of Hg/C ratios in assessments of Hg mobility. In the solid phase of the overlying O-f layer, both Hg concentrations and Hg/C ratios were higher at the southern site (means +/- SD: 0.34 +/- 0.06 mu g g(-1) dw and 0.76 +/- 0.14 mu g g(-1) C, respectively) than at the northern site (0.31 +/- 0.05 mu g g(-1) dw and 0.70 +/- 0.12 mu g g(-1) C, respectively). However, concentrations in the solid phase differed less than might be expected from the difference in current atmospheric input, suggesting that the fraction of natural Hg is still substantial. At both sites, Hg/C ratios in the upper half of the mor layer were only about two thirds of those in the lower half, suggesting that the recent decrease in anthropogenic Hg deposition onto the soil is offset by a natural downward enrichment of Hg due to soil decomposition or other processes. Most interestingly, comparison with soil leachate showed that the average Hg/C ratios in the dissolved phase of the mor layers at both sites did not differ from the average Hg/C ratios in the overlying solid organic matter. These results indicate a simple mobilisation with negligible fractionation, despite differences in Hg deposition patterns, soil chemistry and climatic regimes. Such a straight-forward linkage between Hg and organic matter greatly facilitates the parameterisation of watershed models for assessing the biogeochemical fate, toxic effect and critical level of atmospheric Hg input to forest soils.
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