| 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. |
- Alewell, C, et al.
(författare)
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Stable carbon isotopes as indicators for micro-geomorphic changes in palsa peats
- 2011
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Ingår i: Biogeosciences Discussions. - : Copernicus GmbH. - 1810-6277 .- 1810-6285. ; 8:1, s. 527-548
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Tidskriftsartikel (refereegranskat)abstract
- Palsa peats are unique northern ecosystems formed under an arctic climate and characterizedby an unique biodiversity and ecology. The stability of the palsas are seriouslythreatened by climate warming which will change the permafrost dynamic and5 results in degradation of the mires. We used stable carbon isotope depth profiles intwo palsa mires of Northern Sweden to track environmental change during the formationof the mires. Carbon isotope (13C) depth profile of the yet undisturbed mireStorflaket indicated very low to no degradation of the peat in the water saturated depressions(hollows) but increased rates of anaerobic degradation at the Stordalen site.10 The latter might be induced by degradation of the permafrost cores in the uplifted areas(hummocks) and subsequent braking and submerging of the hummock peat intothe hollows due to climate warming. Carbon isotope depth profiles of hummocks indicateda turn from aerobic mineralisation to anaerobic degradation at a peat depthbetween 4 to 25 cm. The age of these turning point was 14C dated between 150 and15 670 years and could thus not be caused by anthropogenically induced climate change.We found the uplifting of the hummocks due to permafrost heave the most likely explanationfor our findings. We thus concluded that differences in carbon isotope profiles ofthe hollows might point to the disturbance of the mires due to climate warming or dueto differences in hydrology. The characteristic profiles of the hummocks are indicators20 for micro-geomorphic change during permafrost up heaving.
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| 3. |
- Berglund, Åsa, 1978-, et al.
(författare)
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Effects of reduced lead deposition on Pied flycatcher (Ficedula hypoleuca) : tracing exposure routes using stable lead Isotopes
- 2009
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Ingår i: Environmental Science and Technology. - : American Chemical Society. - 0013-936X .- 1520-5851. ; 43:1, s. 208-213
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Tidskriftsartikel (refereegranskat)abstract
- To what extent the lead burden of birds living in strongly contaminated ecosystems is responding to decreased atmospheric lead deposition is not well known. In this study, we measured lead concentrations and stable lead isotope ratios (206Pb/207Pb and 208Pb/207Pb) in liver and feces from pied flycatcher nestlings (Ficedula hypoleuca) along a 90 km pollution gradient from the Rönnskär smelter in northern Sweden. Changes in lead concentration in the birds from 1984 to 2006 were used for assessing the recovery of the environment following reduced lead emissions at the smelter. The 206Pb/207Pb and 208Pb/207Pb ratios were used to identify lead sources to the birds. Lead concentrations in liver and feces have decreased since the 1980s, typically by 9−15% (liver) and 18−40% (feces) as a result of a 98% emission reduction. This relatively weak recovery is explained by a transfer of old lead contaminants accumulated in soil to the birds via their prey, which was evident by a 206Pb/207Pb ratio in liver tissue (1.15 ± 0.01) that overlapped with the ratio in ants (1.16 ± 0.01) and organic soil horizon (1.17 ± 0.01) rather than the current atmospheric lead pollution (1.11 ± 0.01). Our findings suggest that insectivorous birds living around smelters may remain contaminated decades after ceased emissions.
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| 4. |
- Blume-Werry, Gesche, 1985-, et al.
(författare)
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Ideas and perspectives : Alleviation of functional limitations by soil organisms is key to climate feedbacks from arctic soils
- 2023
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Ingår i: Biogeosciences. - : Copernicus Publications. - 1726-4170 .- 1726-4189. ; 20:10, s. 1979-1990
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Tidskriftsartikel (refereegranskat)abstract
- Arctic soils play an important role in Earth's climate system, as they store large amounts of carbon that, if released, could strongly increase greenhouse gas levels in our atmosphere. Most research to date has focused on how the turnover of organic matter in these soils is regulated by abiotic factors, and few studies have considered the potential role of biotic regulation. However, arctic soils are currently missing important groups of soil organisms, and here, we highlight recent empirical evidence that soil organisms' presence or absence is key to understanding and predicting future climate feedbacks from arctic soils. We propose that the arrival of soil organisms into arctic soils may introduce novel functions, resulting in increased rates of, for example, nitrification, methanogenesis, litter fragmentation, or bioturbation, and thereby alleviate functional limitations of the current community. This alleviation can greatly enhance decomposition rates, in parity with effects predicted due to increasing temperatures. We base this argument on a series of emerging experimental evidence suggesting that the dispersal of until-then absent micro-, meso-, and macroorganisms (i.e. from bacteria to earthworms) into new regions and newly thawed soil layers can drastically affect soil functioning. These new observations make us question the current view that neglects organism-driven alleviation effects when predicting future feedbacks between arctic ecosystems and our planet's climate. We therefore advocate for an updated framework in which soil biota and the functions by which they influence ecosystem processes become essential when predicting the fate of soil functions in warming arctic ecosystems.
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| 5. |
- Blume-Werry, Gesche, 1985-, et al.
(författare)
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Invasive earthworms unlock arctic plant nitrogen limitation
- 2020
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Arctic plant growth is predominantly nitrogen (N) limited. This limitation is generally attributed to slow soil microbial processes due to low temperatures. Here, we show that arctic plant-soil N cycling is also substantially constrained by the lack of larger detritivores (earthworms) able to mineralize and physically translocate litter and soil organic matter. These new functions provided by earthworms increased shrub and grass N concentration in our common garden experiment. Earthworm activity also increased either the height or number of floral shoots, while enhancing fine root production and vegetation greenness in heath and meadow communities to a level that exceeded the inherent differences between these two common arctic plant communities. Moreover, these worming effects on plant N and greening exceeded reported effects of warming, herbivory and nutrient addition, suggesting that human spreading of earthworms may lead to substantial changes in the structure and function of arctic ecosystems. Arctic plant growth is predominantly nitrogen limited, where the slow nitrogen turnover in the soil is commonly attributed to the cold arctic climate. Here the authors show that the arctic plant-soil nitrogen cycling is also constrained by the lack of larger detritivores like earthworms.
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| 6. |
- Bottone, Anna, et al.
(författare)
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Sodium hypochlorite as an oxidizing agent for removal of soil organic matter before microplastics analyses
- 2021
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Ingår i: Journal of Environmental Quality. - : John Wiley & Sons. - 0047-2425 .- 1537-2537. ; 51:1, s. 112-122
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Tidskriftsartikel (refereegranskat)abstract
- The omnipresence of microplastics (MPs) across Earth's surface has raised concerns about their environmental impact and created an urgent need for methods to identify them in complex soil and sedimentary matrices. However, detecting MPs in the O horizons of soils is difficult because plastic polymers share many physical and chemical properties with natural soil organic matter (SOM). In this study, we assessed whether sodium hypochlorite (NaOCl), a reagent that can oxidize SOM and simultaneously preserve mineral constituents, can be used for MP analysis and characterization in soil environments. In addition, we scrutinized how factors such as MP size, polymer type, extraction methods, and soil matrix affect the recovery of microplastic particles. We used both hydrophobic and density-dependent separation methods to assess the effects of our oxidation treatment on the recovery of MP. We observed that NaOCl effectively removed SOM without greatly altering the surface properties of resistant MP polymers (polypropylene, polylactic acid, low-density polyethylene, and polyethylene terephthalate), which were characterized using scanning electron microscopy and Fourier-transform infrared spectroscopy after SOM removal. The NaOCl treatment caused some chlorination and formation of additional C–OH bonds on polymer surfaces, which likely contributed to the reduced efficiency of the hydrophobic-based (oil) extraction. We conclude that NaOCl treatment can improve detection of MPs in SOM-rich soil and that recovery of MPs from soils is influenced by MP size, polymer type, extraction method, and soil type, which makes it challenging to develop a universal analytical method.
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| 7. |
- Cerveny, Daniel, et al.
(författare)
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Exposure via biotransformation : oxazepam reaches predicted pharmacological effect levels in European perch after exposure to temazepam
- 2021
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Ingår i: Ecotoxicology and Environmental Safety. - : Academic Press. - 0147-6513 .- 1090-2414. ; 217
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Tidskriftsartikel (refereegranskat)abstract
- It is generally expected that biotransformation and excretion of pharmaceuticals occurs similarly in fish and mammals, despite significant physiological differences. Here, we exposed European perch (Perca fluviatilis) to the benzodiazepine drug temazepam at a nominal concentration of 2 µg L−1 for 10 days. We collected samples of blood plasma, muscle, and brain in a time-dependent manner to assess its bioconcentration, biotransformation, and elimination over another 10 days of depuration in clean water. We observed rapid pharmacokinetics of temazepam during both the exposure and depuration periods. The steady state was reached within 24 h of exposure in most individuals, as was complete elimination of temazepam from tissues during depuration. Further, the biologically active metabolite oxazepam was produced via fish biotransformation, and accumulated significantly throughout the exposure period. In contrast to human patients, where a negligible amount of oxazepam is created by temazepam biotransformation, we observed a continuous increase of oxazepam concentrations in all fish tissues throughout exposure. Indeed, oxazepam accumulated more than its parent compound, did not reach a steady state during the exposure period, and was not completely eliminated even after 10 days of depuration, highlighting the importance of considering environmental hazards posed by pharmaceutical metabolites.
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| 8. |
- Cerveny, D., et al.
(författare)
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Water temperature affects the biotransformation and accumulation of a psychoactive pharmaceutical and its metabolite in aquatic organisms
- 2021
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Ingår i: Environment International. - : Elsevier. - 0160-4120 .- 1873-6750. ; 155
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Tidskriftsartikel (refereegranskat)abstract
- Pharmaceutically active compounds (PhACs) have been shown to accumulate in aquatic and riparian food-webs. Yet, our understanding of how temperature, a key environmental factor in nature, affects uptake, biotransformation, and the subsequent accumulation of PhACs in aquatic organisms is limited. In this study, we tested to what extent bioconcentration of an anxiolytic drugs (temazepam and oxazepam) is affected by two temperature regimes (10 and 20 °C) and how the temperature affects the temazepam biotransformation and subsequent accumulation of its metabolite (oxazepam) in aquatic organisms. We used European perch (Perca fluviatilis) and dragonfly larvae (Sympetrum sp.), which represent predator and prey species of high ecological relevance in food chains of boreal and temperate aquatic ecosystems. Experimental organisms were exposed to target pharmaceuticals at a range of concentrations (0.2–6 µg L−1) to study concentration dependent differences in bioconcentration and biotransformation. We found that the bioconcentration of temazepam in perch was significantly reduced at higher temperatures. Also, temperature had a strong effect on temazepam biotransformation in the fish, with the production and subsequent accumulation of its metabolite (oxazepam) being two-fold higher at 20 °C compared to 10 °C. In contrast, we found no temperature dependency for temazepam bioconcentration in dragonfly larvae and no detectable biotransformation of the parent compound that would result in measurable concentrations of oxazepam in this organism. Our results highlight that while organisms may share the same aquatic ecosystem, their exposure to PhACs may change differently across temperature gradients in the environment.
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| 9. |
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| 10. |
- Fahlman, Johan, et al.
(författare)
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Impacts of Oxazepam on Perch (Perca fluviatilis) Behavior : Fish Familiarized to Lake Conditions Do Not Show Predicted Anti-anxiety Response
- 2021
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 55:6, s. 3624-3633
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Tidskriftsartikel (refereegranskat)abstract
- A current theory in environmental science states that dissolved anxiolytics (oxazepam) from wastewater effluents can reduce anti-predator behavior in fish with potentially negative impacts on prey fish populations. Here, we hypothesize that European perch (Perca fluviatilis) populations being exposed to oxazepam in situ show reduced anti-predator behavior, which has previously been observed for exposed isolated fish in laboratory studies. We tested our hypothesis by exposing a whole-lake ecosystem, containing both perch (prey) and northern pike (Esox lucius; predator), to oxazepam while tracking fish behavior before and after exposure in the exposed lake as well as in an unexposed nearby lake (control). Oxazepam concentrations in the exposed lake ranged between 11 and 24 μg L-1, which is >200 times higher than concentrations reported for European rivers. In contrast to our hypothesis, we did not observe an oxazepam-induced reduction in anti-predator behavior, inferred from perch swimming activity, distance to predators, distance to conspecifics, home-range size, and habitat use. In fact, exposure to oxazepam instead stimulated anti-predator behavior (decreased activity, decreased distance to conspecifics, and increased littoral habitat use) when using behavior in the control lake as a reference. Shoal dynamics and temperature changes may have masked modest reductions in anti-predator behavior due to oxazepam. Although we cannot fully resolve the mechanism(s) behind our observations, our results indicate that the effects of oxazepam on perch behavior in a familiar natural ecosystem are negligible in comparison to the effects of other environmental conditions.
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