| 1. |
- Rydberg, Johan, 1976-, et al.
(författare)
-
Climate driven release of carbon and mercury from permafrost mires increases mercury loading to sub-arctic lakes
- 2010
-
Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 408:20, s. 4778-4783
-
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.
|
|
| 2. |
- Alewell, C, et al.
(författare)
-
Stable carbon isotopes as indicators for micro-geomorphic changes in palsa peats
- 2011
-
Ingår i: Biogeosciences Discussions. - : Copernicus GmbH. - 1810-6277 .- 1810-6285. ; 8:1, s. 527-548
-
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.
|
|
| 3. |
- Berglund, Åsa, 1978-, et al.
(författare)
-
Effects of reduced lead deposition on Pied flycatcher (Ficedula hypoleuca) : tracing exposure routes using stable lead Isotopes
- 2009
-
Ingår i: Environmental Science and Technology. - : American Chemical Society. - 0013-936X .- 1520-5851. ; 43:1, s. 208-213
-
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.
|
|
| 4. |
- Blume-Werry, Gesche, 1985-, et al.
(författare)
-
Ideas and perspectives : Alleviation of functional limitations by soil organisms is key to climate feedbacks from arctic soils
- 2023
-
Ingår i: Biogeosciences. - : Copernicus Publications. - 1726-4170 .- 1726-4189. ; 20:10, s. 1979-1990
-
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.
|
|
| 5. |
- Blume-Werry, Gesche, 1985-, et al.
(författare)
-
Invasive earthworms unlock arctic plant nitrogen limitation
- 2020
-
Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 11:1
-
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.
|
|
| 6. |
- Bottone, Anna, et al.
(författare)
-
Sodium hypochlorite as an oxidizing agent for removal of soil organic matter before microplastics analyses
- 2021
-
Ingår i: Journal of Environmental Quality. - : John Wiley & Sons. - 0047-2425 .- 1537-2537. ; 51:1, s. 112-122
-
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.
|
|
| 7. |
- Cerveny, Daniel, et al.
(författare)
-
Exposure via biotransformation : oxazepam reaches predicted pharmacological effect levels in European perch after exposure to temazepam
- 2021
-
Ingår i: Ecotoxicology and Environmental Safety. - : Academic Press. - 0147-6513 .- 1090-2414. ; 217
-
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.
|
|
| 8. |
- Cerveny, D., et al.
(författare)
-
Water temperature affects the biotransformation and accumulation of a psychoactive pharmaceutical and its metabolite in aquatic organisms
- 2021
-
Ingår i: Environment International. - : Elsevier. - 0160-4120 .- 1873-6750. ; 155
-
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.
|
|
| 9. |
|
|
| 10. |
- Fahlman, Johan, et al.
(författare)
-
Impacts of Oxazepam on Perch (Perca fluviatilis) Behavior : Fish Familiarized to Lake Conditions Do Not Show Predicted Anti-anxiety Response
- 2021
-
Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 55:6, s. 3624-3633
-
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.
|
|
| 11. |
- Fahlman, Johan, 1988-
(författare)
-
The fate and effect of pharmaceuticals in boreal surface waters
- 2020
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Traces of pharmaceuticals are often found in streams, rivers, and lakes as the result of effluent water discharge. This dissertation aims to create a better understanding of the fate of drugs in aquatic ecosystems and how oxazepam, an anxiolytic pharmaceutical commonly detected in surface waters, affects the behavior of perch (Perca fluviatilis). To address these issues, I used a series of large-scale field experiments to evaluate predictions made in controlled laboratory experiments. My dissertation shows that small-scale incubations commonly used to assess the persistence of pharmaceuticals (trimethoprim, diclofenac, hydroxyzine, diphenhydramine and oxazepam) in aquatic environments effectively predicts the fate of dissolved drugs in freshwater during the first week of contamination. However, these experiments and the conceptual models failed to predict that pharmaceuticals can remain dissolved in freshwater for months. In addition, the results suggest that the drugs remain bioactive for months and that the uptake of different drugs varied widely between trophic levels. For example, benthic species generally had a higher affinity to accumulate the studied drugs than species in higher trophic levels; however, the anxiolytic drug oxazepam was found in perch. To test the effect of oxazepam on perch behavior, I used acoustic telemetry to track the perch in situ (i.e., in the ponds). The in situ behavior of perch correlated with laboratory behavior when findings from several trials were merged into multidimensional behavioral profiles of the studied individuals, although oxazepam did not conclusively affect perch behavior in line with earlier theories, when though concentrations were much higher than concentrations measured in any contaminated environments. I conclude that simplified laboratory experiments have some predictive power regarding the fate and effects of pharmaceuticals in complex natural ecosystems, but laboratory environments may underestimate persistence of drugs in aquatic ecosystems and fail to detect important social drivers of animal behavior in natural settings.
|
|
| 12. |
- Fahlman, Johan, et al.
(författare)
-
Using laboratory incubations to predict the fate of pharmaceuticals in aquatic ecosystems
- 2018
-
Ingår i: Environmental Chemistry. - : CSIRO Publishing. - 1448-2517 .- 1449-8979. ; 15:8, s. 463-471
-
Tidskriftsartikel (refereegranskat)abstract
- Environmental contextEnvironmental persistence of excreted pharmaceuticals in aquatic ecosystems is usually predicted using small-scale laboratory experiments assumed to simulate natural conditions. We studied five pharmaceuticals comparing their removal rates from water under laboratory conditions and under natural environmental conditions existing in a large pond. We found that the laboratory conditions did not fully capture the complexity within the pond, which led to different removal rates in the two systems. AbstractEnvironmental persistence is a key property when evaluating risks with excreted pharmaceuticals in aquatic ecosystems. Such persistence is typically predicted using small-scale laboratory incubations, but the variation in aquatic environments and scarcity of field studies to verify laboratory-based persistence estimates create uncertainties around the predictive power of these incubations. In this study we: (1) assess the persistence of five pharmaceuticals (diclofenac, diphenhydramine, hydroxyzine, trimethoprim and oxazepam) in laboratory experiments under different environmental conditions; and (2) use a three-month-long field study in an aquatic ecosystem to verify the laboratory-based persistence estimates. In our laboratory assays, we found that water temperature (TEMP), concentrations of organic solutes (TOC), presence of sediment (SED), and solar radiation (SOL) individually affected dissipation rates. Moreover, we identified rarely studied interaction effects between the treatments (i.e. SOLxSED and TEMPxSOL), which affected the persistence of the studied drugs. Half-lives obtained from the laboratory assays largely explained the dissipation rates during the first week of the field study. However, none of the applied models could accurately predict the long-term dissipation rates (month time-scale) from the water column. For example, the studied antibioticum (trimethoprim) and the anti-anxiety drug (oxazepam) remained at detectable levels in the aquatic environment long after (similar to 150 days) our laboratory based models predicted complete dissipation. We conclude that small-scale laboratory incubations seem sufficient to approximate the short-term (i.e. within a week) dissipation rate of drugs in aquatic ecosystems. However, this simplistic approach does not capture interacting environmental processes that preserve a fraction of the dissolved pharmaceuticals for months in natural water bodies.
|
|
| 13. |
- Ferro-Vázquez, C., et al.
(författare)
-
Comparing podzolization under different bioclimatic conditions
- 2020
-
Ingår i: Geoderma. - : Elsevier. - 0016-7061 .- 1872-6259. ; 377
-
Tidskriftsartikel (refereegranskat)abstract
- Silicate weathering and within soil redistribution of released metals are a near universal process believed to drive the formation of Podzols in various bioclimatic zones, ranging from tropical forest to Arctic environments. Yet the importance of climate and the fractionation of Al, Fe and Si in Podzols remains largely unknown. The aim of this study was to increase our understanding of climate-related variability in the podzolization mechanisms by conducing high-resolution chemical probing of seven soils in different bioclimatic zones and under different hydrological regimes: one well drained and one seasonally hydromorphic from the boreal zone (Sweden), two well-drained Podzols from a mild and humid area (NW Spain) and three, two poorly drained and one well drained soils, from the tropics (Brazil). The analytical strategy included seven selective dissolution techniques, in order to understand the distribution of Fe, Al and Si in organic (high, medium and low stability metal-OM complexes) and inorganic secondary compounds (short-range order and crystalline forms) in relation to their bioclimatic setting. Results indicate that the translocation of metals is coupled to the soil organic matter (SOM) mobilization in all three bioclimatic zones. The accumulation of metals and organic matter in the spodic horizons, in contrast, is contingent upon temperature, as well as on the local hydrological conditions and pH. Multivariate statistics allowed to identify the effect of climate, of soil hydrological conditions and of parent material in the soil vertical development. The high vertical resolution sampling and the extended fractionation employed were key for detecting the differences in Al, Fe and SOM dynamics in the studied soils, and revealed that different podzolization mechanisms are active in each bioclimatic zone.
|
|
| 14. |
|
|
| 15. |
- Hellström, Gustav, et al.
(författare)
-
Environmentally relevant concentrations of the common anxiolytic pharmaceutical oxazepam do not have acute effect on spawning behavior in mature male Atlantic salmon (Salmo salar) parr
- 2020
-
Ingår i: Journal of Applied Ichthyology. - : John Wiley & Sons. - 0175-8659 .- 1439-0426. ; 36:1, s. 105-112
-
Tidskriftsartikel (refereegranskat)abstract
- Low concentrations of psychiatric drugs are commonly found in surface waters around the world, and their ability to alter behaviors in aquatic fauna has raised concerns about ecological effects. One critical effect that contamination can have in aquatic systems is modifications of reproductive behaviors. In this study, we hypothesized that oxazepam, a common anxiolytic drug and aquatic contaminant previously shown to induce anti-anxiety behavior in salmonids, also affects the reproductive behavior of Atlantic salmon (Salmo salar). To test this hypothesis, small sexually mature Atlantic salmon males (mature parr) were exposed to concentrations of oxazepam comparable to that of effluent water (1.9 mu g/L). After 5 days of exposure, their reproductive behavior was compared with that of unexposed control individuals. Behavior was monitored in a large-scale flume aquarium that also contained a large male and a female to mimic natural spawning conditions for Atlantic salmon. Three behaviors were quantified for the mature parr; (a) amount of courting behavior towards female, (b) proximity to female, and (c) amount of attacks received from the large male. In contrast to our hypothesis, no difference in either courting behavior, proximity to female, or received aggression could be found between exposed and control male parr. Hence, our results indicate that there is no acute effect of the highest levels of oxazepam concentration reported for urban environments on spawning behavior of mature male parr, although chronic effects could not be ruled out.
|
|
| 16. |
- Jerand, Philip, 1985-, et al.
(författare)
-
The legacy of ecological imperialism in the Scandes : earthworms and their implications for Arctic research
- 2023
-
Ingår i: Arctic, Antarctic and Alpine research. - : Taylor & Francis. - 1523-0430 .- 1938-4246. ; 55:1
-
Tidskriftsartikel (refereegranskat)abstract
- In the nineteenth century, numerous settlements were established in the alpine region of Fennoscandia (the Scandes), an area that later became a major international scene for Arctic research. Here we raise awareness of this era and show that earthworm-driven bioturbation in “pristine” soils around contemporary Arctic research infrastructure is caused by soil fauna left behind during early land use. We use soil preserved under an alpine settlement to highlight that soils were not bioturbated when the first house was built at a site where bioturbation is now widespread. A review of archived material with unique site-specific chronology constrained the onset of bioturbation to the post-1871 era. Our results suggest that small-scale land use introduced earthworms that now thrive far beyond the realms of former cultivated fields. The legacy of soil fauna from this example of “ecological imperialism” still lingers and should be considered when studying soils of the Scandes.
|
|
| 17. |
|
|
| 18. |
- Jonsson, Hanna, et al.
(författare)
-
Cascading effects of earthworm invasion increase graminoid density and rodent grazing intensities
- 2024
-
Ingår i: Ecology. - : The Ecological Society of America. - 0012-9658 .- 1939-9170. ; 105:2
-
Tidskriftsartikel (refereegranskat)abstract
- Human-mediated dispersal of non-native earthworms can cause substantial changes to the functioning and composition of ecosystems previously earthworm-free. Some of these earthworm species have the potential to “geoengineer” soils and increase plant nitrogen (N) uptake. Yet the possible consequences of increased plant N concentrations on rodent grazing remains poorly understood. In this study, we present findings from a common garden experiment with two tundra communities, meadow (forb dominated) and heath (shrub dominated), half of them subjected to 4 years of earthworm presence (Lumbricus spp. and Aporrectodea spp.). Within four summers, our earthworm treatment changed plant community composition by increasing graminoid density by, on average, 94% in the heath vegetation and by 49% in the meadow. Rodent winter grazing was more intense on plants growing in soils with earthworms, an effect that coincided with higher N concentrations in plants, indicating a higher palatability. Even though earthworms reduced soil moisture, plant community productivity, as indicated by vegetation greenness (normalized difference vegetation index), was not negatively impacted. We conclude that earthworm-induced changes in plant composition and trophic interactions may fundamentally alter the functioning of tundra ecosystems.
|
|
| 19. |
- Jonsson, Micael, 1972-, et al.
(författare)
-
Antihistamines and aquatic insects : Bioconcentration and impacts on behavior in damselfly larvae (Zygoptera)
- 2014
-
Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 472, s. 108-111
-
Tidskriftsartikel (refereegranskat)abstract
- Because aquatic insects use histamines as neurotransmitters, adverse impacts on aquatic insects living in aquatic environments that receive antihistamines with wastewater effluent are plausible. In this study, we exposed damselfly larvae to low concentrations of two commonly used antihistamines (Hydroxyzine and Fexofenadine, 360 +/- 42 and 2200 +/- 43 ng 1(-1), respectively), and recorded damselfly larvae behavior before and after exposure. Further, after the second set of behavioral assays was performed, we quantified bioconcentration of the antihistamines in the damselfly bodies. Our results showed significant changes in damselfly behavior following antihistamine exposure. After Hydroxyzine exposure, the damselfly larvae became less active, and they showed reduced fleeing response (i.e. increased boldness) after being exposed to Fexofenadine, the latter also being significantly different from the non-exposed (control) individuals. Further, we found high levels of bioconcentration in the damselflies; Hydroxyzine showed an average bioconcentration factor (BCF) of 2000. As such, our results indicate that low concentrations of antihistamines can have sub-lethal effects on aquatic insects manifested as behavioral changes, and that bioconcentration of these substances can be high. Therefore, the need to investigate the impact of emergent aquatic contaminants also on aquatic insects, and on behaviors that are of ecological importance, is further highlighted. (c) 2013 Elsevier B.V. All rights reserved.
|
|
| 20. |
- Jonsson, Micael, 1972-, et al.
(författare)
-
Effects of an antihistamine on carbon and nutrient recycling in streams
- 2015
-
Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 538, s. 240-245
-
Tidskriftsartikel (refereegranskat)abstract
- In stream ecosystems, microbes and macroinvertebrates consume leaf litter deposited from the riparian vegetation, and thereby recycle resources tied up in the litter. Several environmental variables influence rates of this recycling, but it is not well known if common pharmaceuticals, such as antihistamines, originating from waste-water effluent, have additional impacts. Exposure to dilute concentrations of antihistamines may adversely influence aquatic detritivorous invertebrates, because invertebrates use histamines for neurotransmission, resulting in hampered recycling of resource tied up in leaf detritus. In this study, we therefore investigated if the antihistamine fexofenadine, at a concentration of 2000 ng l(-1), alters rates of leaf litter decomposition in stream microcosms. Stonefly larvae (n = 10, per microcosm), together with natural microbial communities, served as main decomposer organisms on alder leaf litter. First, we used 30 microcosms containing fexofenadine, while the other 30 served as non-contaminated controls, and of each 30 microcosms, 14 contained stonefly larvae and microbes, while the remaining 16 contained only microbes. We found, in contrast to our hypothesis, that fexofenadine had no effect on leaf litter decomposition via impacts on the stonefly larvae. However, independent on if stoneflies were present or not, concentrations of organic carbon (TOC) and nitrogen (N) were strongly affected, with 20-26 and 24-31% lower concentrations of TOC and N, respectively, in the presence of fexofenadine. Second, in a scaled down follow-up experiment we found that microbial activity increased by 85%, resulting in a 10% decrease in pH, in the presence of fexofenadine. While the antihistamine concentration we used is higher than those thus far found in the field (1-10 ng l(-1)), it is still 100 times lower than the predicted no-effect concentration for fexofenadine. As such, our results indicate that low mu g l(-1) levels of antihistamines can have an effect on carbon and nutrient recycling in aquatic system. (C) 2015 Elsevier B.V. All rights reserved.
|
|
| 21. |
- Jonsson, Micael, et al.
(författare)
-
High-speed imaging reveals how antihistamine exposure affects escape behaviours in aquatic insect prey
- 2019
-
Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 648, s. 1257-1262
-
Tidskriftsartikel (refereegranskat)abstract
- Aquatic systems receive a wide range of pharmaceuticals that may have adverse impacts on aquatic wildlife. Among these pharmaceuticals, antihistamines are commonly found, and these substances have the potential to influence the physiology of aquatic invertebrates. Previous studies have focused on how antihistamines may affect behaviours of aquatic invertebrates, but these studies probably do not capture the full consequences of antihistamine exposure, as traditional recording techniques do not capture important animal movements occurring at the scale of milliseconds, such as prey escape responses. In this study, we investigated if antihistamine exposure can impact escape responses in aquatic insect, by exposing damselfly (Coenagrion hastulatum) larvae to two environmentally relevant concentrations (0.1 and 1 μg L−1) of diphenhydramine. Importantly, we used a high-speed imaging approach that with high-time resolution captures details of escape responses and, thus, potential impacts of diphenhydramine on these behaviours. Our results show overall weak effects of antihistamine exposure on the escape behaviours of damselfly larvae. However, at stage 2 of the C-escape response, we found a significant increase in turning angle, which corresponds to a reduced swimming velocity, indicating a reduced success at evading a predator attack. Thus, we show that low concentrations of an antihistamine may affect behaviours strongly related to fitness of aquatic insect prey – effects would have been overlooked using traditional recording techniques. Hence, to understand the full consequences of pharmaceutical contamination on aquatic wildlife, high-speed imaging should be incorporated into future environmental risk assessments.
|
|
| 22. |
- Keen, Sara C., et al.
(författare)
-
Non-native species change the tune of tundra soils : novel access to soundscapes of the Arctic earthworm invasion
- 2022
-
Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 838
-
Tidskriftsartikel (refereegranskat)abstract
- Over the last decade, an increasing number of studies have used soundscapes to address diverse ecological questions. Sound represents one of the few sources of information capable of providing in situ insights into processes occurring within opaque soil matrices. To date, the use of soundscapes for soil macrofauna monitoring has been experimentally tested only in controlled laboratory environments. Here we assess the validity of laboratory predictions and explore the use of soil soundscape proxies for monitoring soil macrofauna (i.e., earthworm) activities in an outdoor context. In a common garden experiment in northern Sweden, we constructed outdoor mesocosm plots (N = 36) containing two different Arctic vegetation types (meadow and heath) and introduced earthworms to half of these plots. Earthworms substantially altered the ambient soil soundscape under both vegetation types, as measured by both traditional soundscape indices and frequency band power levels, although their acoustic impacts were expressed differently in heath versus meadow soils. While these findings support the as-of-yet untapped promise of using belowground soundscape analyses to monitor soil ecosystem health, direct acoustic emissions from earthworm activities appear to be an unlikely proxy for tracking worm activities at daily timescales. Instead, earthworms indirectly altered the soil soundscape by ‘re-engineering’ the soil matrix: an effect that was dependent on vegetation type. Our findings suggest that long-term (i.e., seasonal) earthworm activities in natural soil settings can likely be monitored indirectly via their impacts on soundscape measures and acoustic indices. Analyzing soil soundscapes may enable larger-scale monitoring of high-latitude soils and is directly applicable to the specific case of earthworm invasions within Arctic soils, which has recently been identified as a potential threat to the resilience of high-latitude ecosystems. Soil soundscapes could also offer a novel means to monitor soils and soil-plant-faunal interactions in situ across diverse pedogenic, agronomic, and ecological systems.
|
|
| 23. |
- Klaminder, Jonatan, 1976-, et al.
(författare)
-
Holes in the tundra : Invasive earthworms alter soil structure and moisture in tundra soils
- 2023
-
Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 859
-
Tidskriftsartikel (refereegranskat)abstract
- Human introductions have resulted in earthworms establishing in the Arctic, species known to cause cascading ecosystem change. However, few quantitative outdoor experiments have been performed that describe how these soil modifying earthworms are reshaping structures in tundra soils. In this study, we used three-dimensional (3-D) X-ray images of soil cores (approximately 10 cm diameter, 20 cm height, N = 48) to assess how earthworms (Aporrectodea sp. and Lumbricus sp.) affect soil structure and macropore networks in an outdoor mesocosm experiment that lasted four summers. Effects were assessed in both shrub-dominated (heath) and herb-dominated (meadow) tundra. Earthworms almost doubled the macroporosity in meadow soils and tripled macroporosity in heath. Interestingly, the fractal dimension of macropores decreased in response to earthworm burrowing in both systems, indicating that the presence of earthworms reduced the geometric complexity in comparison to other pore-generating processes active in the tundra. Observed effects on soil structure occurred along with a dramatically reduced soil moisture content, which was observed the first winter after earthworm introduction in the meadow. Our findings suggest that predictions of future changes in vegetation and soil carbon pools in the Arctic should include major impacts on soil properties that earthworms induce.
|
|
| 24. |
- Klaminder, Jonatan, 1976-, et al.
(författare)
-
Landscape of ice and fire : uniquely well-preserved scots pine trunks reveal forest fires near the retreating weichselian ice margin
- 2024
-
Ingår i: Vegetation History and Archaeobotany. - : Springer. - 0939-6314 .- 1617-6278. ; 33, s. 519-527
-
Tidskriftsartikel (refereegranskat)abstract
- Environmental conditions for trees that established in central Fennoscandia shortly after the final retreat of the Weichselian ice sheet remain poorly understood. In this study we examine tree rings of five well-preserved Pinus sylvestris (Scots pines) that grew in the area in front of the retreating ice sheet in northern Sweden. They became buried in flood sediments deposited by a glacial outburst flood (jökulhlaup) about 9.5–9.9 kyr cal bp and the aim of our study was to search for information regarding damage from fires and bioclimatic conditions in their ancient tree ring records. Our analysis, providing a glimpse into the local early Holocene environment in north-central Sweden, suggests that: 1, there were repeated fires (four fire events detected) during the early Holocene; and 2, bioclimatic conditions when the ancient pines were growing resembled those of modern sub-alpine pine woods. The latter is indicated by their patterns of tree ring growth (growth rate and variation), which were statistically similar to those of pines growing in sub-alpine woods with an open canopy, but different from pines in protected and managed boreal forests. Lower δ13C for the ancient latewood in comparison to pine wood from trees growing near the Scandinavian mountains before the 1850s were probably caused both by stomata fractionation due to lower atmospheric CO2 during the early Holocene and by the moist local environment created by the nearby ancient Ancylus lake, which preceded the Baltic Sea. Periods with cloudy and cold summers were also indicated by the occurrence of ‘false rings’. Finds of charred fragments of Calluna vulgaris (heather, ling), an understory shrub that can burn even with a relatively high moisture content, suggest that heath vegetation was crucial to make fire a reoccurring ecological factor in the area during the early Holocene.
|
|
| 25. |
- Klaminder, Jonatan, 1976-, et al.
(författare)
-
Less anxious salmon smolt become easy prey during downstream migration
- 2019
-
Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 687, s. 488-493
-
Tidskriftsartikel (refereegranskat)abstract
- Hatchery-reared salmon smolt used for supplementary stocking often display poor migration behavior compared to wild smolt, which reduces the success of this management action. Oxazepam, an anxiolytic drug, has been shown to intensify salmon smolt migration in mesocosm experiments, and treatment with this drug has, therefore, been suggested as a management option to improve downstream smolt migration. In this study, we tested this by assessing migration performance of hatchery-reared Atlantic salmon (Salmo salar) smolt along a 21-km long natural river-to-sea migration route in a boreal river in Northern Sweden. Using acoustic telemetry, the migration rate and survival of smolt that had been exposed to oxazepam (200 mu g L-1, N = 20) was monitored and compared with a control group (N = 20) of unexposed smolt. Exposed smolt took significantly longer time to initiate migration after release compared to the control fish, but after that we observed no significant difference in downstream migration speed. However, exposed smolt had considerably higher probability of being predated on compared to control smolt. We attribute these results to increased risk-taking and higher activity in oxazepam-exposed smolt, which in turn increased initial non-directional exploratory behavior and decreased predator vigilance. These results are discussed based on current concerns for ecological implications of behavioral modifications induced by pharmaceutical pollution and climate change. We conclude that exposure to oxazepam is an unsuitable management option to prime migration of reared salmon in natural systems.
|
|
| 26. |
- Klaminder, Jonatan, 1976-, et al.
(författare)
-
Silicate mineral weathering rate estimates : Are they precise enough to be useful when predicting the recovery of nutrient pools after harvesting?
- 2011
-
Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 261:1, s. 1-9
-
Tidskriftsartikel (refereegranskat)abstract
- Are current estimates of silicate minerals weathering rates precise enough to predict whether nutrient pools will recover after forest harvesting? Answering this question seems crucial for sustainable forestry practices on silicate dominated soils. In this paper, we synthesize estimated Ca and K weathering rates (derived using seven different approaches) from a forested area in northern Sweden (the Svartberget-Krycklan catchment) to evaluate the precision of weathering rate estimates. The methods were: mass-balance budgets (catchment and pedon-scale); long-term weathering losses inferred from weathered soil profiles (using zirconium as a conservative tracer); strontium isotopes ((86)Sr/(85)Sr) as proxy for catchment export of geogenic Ca; climate based regressions; a steady-state, process-based weathering model (PROFILE) and a dynamic, conceptual catchment geochemistry model (MAGIC). The different methods predict average weathering rates of 0.67 +/- 0.71 g Ca m(-2) year(-1) (mean +/- stdev) and 0.39 +/- 0.38 g K m(-2) year(-1), suggesting a cumulative weathering release during a forest rotation period of 100 years that is the same magnitude as losses induced by forest harvesting at the end of the period. Clearly, forestry practices have the capacity to significantly alter the long-term nutrient status of the soil and cation concentrations in soil-water runoff. However, the precision in weathering estimates are lower than that needed to distinguish between effects on nutrient pools by different forest practices (complete-tree harvesting versus conventional stem only harvest). Therefore, we argue that nutrient budgets, where weathering rates play a crucial role, cannot be used as basis for resolving whether different harvesting techniques will allow nutrient pools to recover within one rotation period. Clearly, this hampers the prerequisite for sound decision making regarding forestry practices on silicate mineral dominated soils. (C) 2010 Elsevier B.V. All rights reserved.
|
|
| 27. |
- Klaminder, Jonatan, 1976-, et al.
(författare)
-
The conceptual imperfection of aquatic risk assessment tests : highlighting the need for tests designed to detect therapeutic effects of pharmaceutical contaminants
- 2014
-
Ingår i: Environmental Research Letters. - : Institute of Physics Publishing (IOPP). - 1748-9326. ; 9:8, s. 084003-
-
Tidskriftsartikel (refereegranskat)abstract
- Standardized ecotoxicological tests still constitute the fundamental tools when doing risk-assessment of aquatic contaminants. These protocols are managed towards minimal mortality in the controls, which is not representative for natural systems where mortality is often high. This methodological bias, generated from assays where mortality in the control group is systematically disregarded, makes it difficult to measure therapeutic effects of pharmaceutical contaminants leading to lower mortality. This is of concern considering that such effects on exposed organisms still may have substantial ecological consequences. In this paper, we illustrate this conceptual problem by presenting empirical data for how the therapeutic effect of Oxazepam-a common contaminant of surface waters-lower mortality rates among exposed Eurasian perch (Perca fluviatilis) from wild populations, at two different life stages. We found that fry hatched from roe that had been exposed to dilute concentrations (1.1 +/- 0.3 mu g l(-1)) of Oxazepam for 24 h 3-6 days prior to hatching showed lower mortality rates and increased activity 30 days after hatching. Similar effects, i.e. increased activity and lower mortality rates were also observed for 2-year old perch exposed to dilute Oxazepam concentrations (1.2 +/- 0.4 mu g l(-1)). We conclude that therapeutic effects from pharmaceutical contaminants need to be considered in risk assessment assays to avoid that important ecological effects from aquatic contaminants are systematically missed.
|
|
| 28. |
- Klaminder, Jonatan, 1976-
(författare)
-
The fate of airborne lead pollution in boreal forest soils
- 2005
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Lead has a more than three-millennia-long pollution history in Europe. Metal production, burning of coal and use of leaded petrol resulted in a significant pollution of the atmosphere. As a consequence of atmospheric fallout, the Swedish boreal forest is strongly contaminated by airborne lead pollution. High levels of lead in the soil and soil pore water are of concern because the soil fauna, plants and aquatic biota may respond negatively to this toxic element. The fate of the accumulated pool of pollution in the soil is not well known. In this thesis, I determine four variables of importance for increasing our knowledge about the past, present and future lead levels in the boreal forest soil: 1) the pre-pollution atmospheric deposition rate of lead; 2) the upward flux of lead from deeper soil layers to near-surface horizons as a result of plant uptake; 3) the mean residence time of lead in the mor layer (the organic horizon at the surface of forest soils); and 4) the vertical and lateral transport of pollution lead within the mineral soil and to streams. Lead concentration measurements and stable lead isotope analyses were used for distinguishing pollution lead from natural lead in cores from ombrotrophic bogs, forest soil profiles, forest mosses, soil-water and stream-water samples. The results clearly stress that the boreal forest ecosystem is totally dominated by pollution lead. This is proved by low 206Pb/207Pb ratios (mainly between 1.14 and 1.20) in the mor layer, forest plants and stream water, while the local geogenic lead of the mineral soil (C-horizon) has high ratios (> 1.30). The dominance of pollution in the mor layer is caused by high deposition rates of airborne lead pollution, minute transport rates of lead from the mineral soil by forest plants (about 0.02 mg lead m-2 year-1) and a long mean residence time of the deposited lead (~250 years for mature forest). In the pristine pre-pollution environment, lead was a rare element due to low atmospheric deposition rates (0.001 to 0.01 mg m-2 year-1). It is estimated that the present lead inventory in the mor layer is up to 100 times higher than in the pristine environment where ≤ 8 mg m-2 was present in the mor. The levels in this biologically important horizon will decrease at a very slow rate and it will take centuries for the deeper part of the mor layer to fully respond to decreasing atmospheric inputs. In a hypothetic scenario with a ceased atmospheric lead deposition, the pool of pollution lead will ultimately be redistributed to deeper water-saturated soil layers from where a lateral transport to surface waters occurs. In the studied catchment, the export of pollution lead from the soil to the stream is estimated to peak slightly about one thousand years from now.
|
|
| 29. |
- Klaminder, Jonatan, 1976-, et al.
(författare)
-
The origin of lead in the organic horizon of tundra soils : Atmospheric deposition, plant translocation from the mineral soil or soil mineral mixing?
- 2011
-
Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 409:20, s. 4344-50
-
Tidskriftsartikel (refereegranskat)abstract
- Knowledge of the anthropogenic contribution to lead (Pb) concentrations in surface soils in high latitude ecosystems is central to our understanding of the extent of atmospheric Pb contamination. In this study, we reconstructed fallout of Pb at a remote sub-arctic region by using two ombrotrophic peat cores and assessed the extent to which this airborne Pb is able to explain the isotopic composition ((206)Pb/(207)Pb ratio) in the O-horizon of tundra soils. In the peat cores, long-range atmospheric fallout appeared to be the main source of Pb as indicated by temporal trends that followed the known European pollution history, i.e. accelerated fallout at the onset of industrialization and peak fallout around the 1960s-70s. The Pb isotopic composition of the O-horizon of podzolic tundra soil ((206)Pb/(207)Pb=1.170±0.002; mean±SD) overlapped with that of the peat ((206)Pb/(207)Pb=1.16±0.01) representing a proxy for atmospheric aerosols, but was clearly different from that of the parent soil material ((206)Pb/(207)Pb=1.22-1.30). This finding indicated that long-range fallout of atmospheric Pb is the main driver of Pb accumulation in podzolic tundra soil. In O-horizons of tundra soil weakly affected by cryoturbation (cryosols) however, the input of Pb from the underlying mineral soil increased as indicated by (206)Pb/(207)Pb ratios of up to 1.20, a value closer to that of local soil minerals. Nevertheless, atmospheric Pb appeared to be the dominant source in this soil compartment. We conclude that Pb concentrations in the O-horizon of studied tundra soils - despite being much lower than in boreal soils and representative for one of the least exposed sites to atmospheric Pb contaminants in Europe - are mainly controlled by atmospheric inputs from distant anthropogenic sources.
|
|
| 30. |
- Klaminder, Jonatan, 1976-, et al.
(författare)
-
Using Short-lived Radionuclides to Estimate Rates of Soil Motion in Frost Boils
- 2014
-
Ingår i: Permafrost and Periglacial Processes. - : Wiley. - 1099-1530 .- 1045-6740. ; 25:3, s. 184-193
-
Tidskriftsartikel (refereegranskat)abstract
- Cryoturbation in high-latitude soils is crucial for the long-term cycling of elements, but the rates of soil motion are poorly constrained. Here, we test whether the rate of frost creep, soil erosion and vertical soil mixing in frost boils can be estimated using short-lived radionuclides (Cs-137 and Pb-210). We find a small-scale variation in Cs-137 and Pb-210 inventories in the lower levels of the eroding regions of frost boils in comparison to the expected depositional sites; hence, the distribution of the radionuclides appears to reflect a lateral transport of atmospheric fallout from the centre of the boil (inner domain) towards the surrounding soil (outer domain). C-14 dating of the soil indicates that fallout of Cs-137 was mobile in the soil and that Pb-210 moved with the soil matrix. A soil creep model and a surface soil erosion model are derived and applied to the lateral and vertical distributions of Pb-210 in the frost boil. Both models predict the expected trajectories of soil motion and provide rates of creep, erosion and mixing at a mm yr(-1) to cm yr(-1) scale. The distribution of Pb-210 provides new insights about the processes and rates of soil mass movement in frost boils, if sound mass-balance models are applied.
|
|
| 31. |
- Klaus, Marcus, et al.
(författare)
-
Cryogenic Soil Activity along Bioclimatic Gradients in Northern Sweden : Insights from Eight Different Proxies
- 2013
-
Ingår i: Permafrost and Periglacial Processes. - : John Wiley & Sons. - 1045-6740 .- 1099-1530. ; 24:3, s. 210-223
-
Tidskriftsartikel (refereegranskat)abstract
- Cryogenic soil activity caused by differential soil movements during freeze-thaw cycles is of fundamental importance for Arctic ecosystem functioning, but its response to climate warming is uncertain. Eight proxies of cryogenic soil activity (including measurements of soil surface motion, vegetation and grey values of aerial photographs) were examined at eight study sites where non-sorted patterned ground spans an elevation gradient (400-1150 m asl) and a precipitation gradient (300-1000 mm yr(-1)) near Abisko, northern Sweden. Six proxies were significantly correlated with each other (mean |r|=0.5). Soil surface motion increased by three to five times along the precipitation gradient and was two to four times greater at intermediate elevations than at low and high elevations, a pattern reflected by vegetation assemblages. The results suggest that inferences about how cryogenic soil activity changes with climate are independent of the choice of the proxy, although some proxies should be applied carefully. Four preferred proxies indicate that cryogenic soil activity may respond differently to climate warming along the elevation gradient and could be greatly modified by precipitation. This underlines the strong but spatially complex response of cryogenic processes to climate change in the Arctic. Copyright (c) 2013 John Wiley & Sons, Ltd.
|
|
| 32. |
- Klaus, Marcus, et al.
(författare)
-
Greenhouse gas emissions from boreal inland waters unchanged after forest harvesting
- 2018
-
Ingår i: Biogeosciences. - Goettingen, Germany : Copernicus GmbH. - 1726-4170 .- 1726-4189. ; 15:18, s. 5575-5594
-
Tidskriftsartikel (refereegranskat)abstract
- Forestry practices often result in an increased export of carbon and nitrogen to downstream aquatic systems. Although these losses affect the greenhouse gas (GHG) budget of managed forests, it is unknown if they modify GHG emissions of recipient aquatic systems. To assess this question, air-water fluxes of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) were quantified for humic lakes and their inlet streams in four boreal catchments using a before-after control-impact experiment. Two catchments were treated with forest clear-cuts followed by site preparation (18 % and 44 % of the catchment area). GHG fluxes and hydrological and physicochemical water characteristics were measured at multiple locations in lakes and streams at high temporal resolution throughout the summer season over a 4-year period. Both lakes and streams evaded all GHGs. The treatment did not significantly change GHG fluxes in streams or lakes within 3 years after the treatment, despite significant increases of CO2 and CH4 concentrations in hillslope groundwater. Our results highlight that GHGs leaching from forest clear-cuts may be buffered in the riparian zone-stream continuum, likely acting as effective biogeochemical processors and wind shelters to prevent additional GHG evasion via downstream inland waters. These findings are representative of low productive forests located in relatively flat landscapes where forestry practices cause only a limited initial impact on catchment hydrology and biogeochemistry.
|
|
| 33. |
- Lagesson, Annelie, 1986-
(författare)
-
Fish on drugs : behaviour modifying contaminants in aquatic ecosystems
- 2018
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Contamination of surface waters is a worldwide problem. One group of emerging contaminants that reach aquatic ecosystems via sewage treatment plant effluents and agricultural run-offs is pharmaceuticals. Impacts of pharmaceuticals on the behaviour of aquatic organisms can have important ecological and evolutionary consequences because behaviour is directly linked to fitness. The aim of my doctoral thesis was to increase our understanding of the fate and effects of behaviour modifying drugs in aquatic ecosystems.While studying an aquatic ecosystem spiked with pharmaceuticals, I found that the benthic species at the bottom of the food chain were the main receivers (highest bioaccumulation factor; BAF) while fish at the top of the food web had the lowest uptake of the studied drugs. Interestingly, the BAF of the anxiolytic pharmaceutical oxazepam, increased in fish (perch; Perca fluviatilis) over the study period, suggesting that this drug can be transferred between trophic levels in food webs. To assess whether oxazepam could affect growth and survival in perch, I exposed perch populations to oxazepam for 2-months in a replicated pond experiment. In this study, I tested the hypothesis that oxazepam exposed perch would grow faster but also suffer from increased predation. Oxazepam has been shown previously to induce ‘anti-anxiety’ behaviours that improve foraging but may also make individuals more exposed to predators. In contrast, I found no statistically significant increase in growth and mortality in the exposed perch. However, the study revealed that the natural predator of perch (pike; Esox lucius) became less effective at catching prey when exposed to oxazepam. This exposure effect on predation efficiency likely contributed to the absence of predation effects in the exposed ponds. In two following laboratory studies I investigated effects of behaviour modifying drugs (oxazepam and a growth hormone, 17β-trenbolone) in combination with additional stressors (temperature and predator cues). Drug and temperature interactions were found for 17β-trenbolone, where water temperature interacted with treatment to induce changes in predator escape behaviour, boldness, and exploration in mosquitofish (Gambusia holbrooki). However, in the other study, we found that oxazepam, temperature, and predator cue all affected perch ‘anti-anxiety’ behaviours, but independently.I conclude that pharmaceuticals can alter ecologically important behaviours in fish, and that at least some, can accumulate in aquatic food webs. It seems that in situ effects of behaviour modifying drugs in aquatic ecosystems depend on both species-specific responses and abiotic interactions. As such, it is far from straightforward to predict net ecosystem effects based on experiments conducted using single species and static conditions. Future studies should assess the effects of pharmaceuticals in aquatic ecosystems under more complex conditions for us to gain a better understanding of what consequences behaviour modifying drugs have in the environment.
|
|
| 34. |
- Lagesson, Annelie, et al.
(författare)
-
Fish on steroids : Temperature-dependent effects of 17β-trenbolone on predator escape, boldness, and exploratory behaviors
- 2019
-
Ingår i: Environmental Pollution. - : Elsevier. - 0269-7491 .- 1873-6424. ; 245, s. 243-252
-
Tidskriftsartikel (refereegranskat)abstract
- Hormonal growth promoters (HGPs), widely used in beef cattle production globally, make their way into the environment as agricultural effluent—with potential impacts on aquatic ecosystems. One HPG of particular concern is 17β-trenbolone, which is persistent in freshwater habitats and can affect the development, morphology and reproductive behaviors of aquatic organisms. Despite this, few studies have investigated impacts of 17β-trenbolone on non-reproductive behaviors linked to growth and survival, like boldness and predator avoidance. None consider the interaction between 17β-trenbolone and other environmental stressors, such as temperature, although environmental challenges confronting animals in the wild seldom, if ever, occur in isolation. Accordingly, this study aimed to test the interactive effects of trenbolone and temperature on organismal behavior. To do this, eastern mosquitofish (Gambusia holbrooki) were subjected to an environmentally-relevant concentration of 17β-trenbolone (average measured concentration 3.0 ± 0.2 ng/L) or freshwater (i.e. control) for 21 days under one of two temperatures (20 and 30 °C), after which the predator escape, boldness and exploration behavior of fish were tested. Predator escape behavior was assayed by subjecting fish to a simulated predator strike, while boldness and exploration were assessed in a separate maze experiment. We found that trenbolone exposure increased boldness behavior. Interestingly, some behavioral effects of trenbolone depended on temperature, sex, or both. Specifically, significant effects of trenbolone on male predator escape behavior were only noted at 30 °C, with males becoming less reactive to the simulated threat. Further, in the maze experiment, trenbolone-exposed fish explored the maze faster than control fish, but only at 20 °C. We conclude that field detected concentrations of 17β-trenbolone can impact ecologically important behaviors of fish, and such effects can be temperature dependent. Such findings underscore the importance of considering the potentially interactive effects of other environmental stressors when investigating behavioral effects of environmental contaminants.
|
|
| 35. |
- Larsbo, Mats, et al.
(författare)
-
Quantifying earthworm soil ingestion from changes in vertical bulk density profiles
- 2024
-
Ingår i: European journal of soil biology. - : Elsevier. - 1164-5563 .- 1778-3615. ; 120
-
Tidskriftsartikel (refereegranskat)abstract
- Soil mixing by earthworms can have a large impact on the fate of nutrients and pollutants and on the soil's ability to sequester carbon. Nevertheless, methods to quantify earthworm ingestion and egestion under field conditions are largely lacking. Soils of the Fennoscandian tundra offer a special possibility for such quantifications, as these soils commonly lack burrowing macrofauna and exhibit a well-defined O horizon with low bulk density on top of a mineral soil with higher density. Since ingestion-egestion mixes the two soil layers, the temporal changes in the bulk density profile of such soils may be useful for estimating field ingestion rates. In this study, we applied a model for earthworm burrowing through soil ingestion to observed changes in soil densities occurring in a mesocosm experiment carried out in the arctic during four summers with intact soil. The earthworms present in the mesocosms were Aporrectodea trapezoides, Aporrectodea tuberculata, Aporrectodea rosea, Lumbricus rubellus and Lumbricus Terrestris (fourth season only). We show that changes in soil density profiles can indeed be used to infer earthworm ingestion rates that are realistic in comparison to literature values. Although uncertainties in parameter values were sometimes large, the results from this study suggest that soil turnover rates and endogeic earthworm soil ingestion rates in tundra heath and meadow soils may be as high as those reported for temperate conditions. Such large ingestion rates can explain observed large morphological changes in arctic soils where dispersing earthworms have resulted in complete inmixing of the organic layer into the mineral soil. Our approach is applicable to soil profiles with marked vertical differences in bulk density such as the soils of the Fennoscandian tundra where earthworms are currently dispersing into new areas and to layered repacked soil samples that are incubated in the field.
|
|
| 36. |
- Leander, Johan, et al.
(författare)
-
Bubble barriers to guide downstream migrating Atlantic salmon (Salmo salar) : An evaluation using acoustic telemetry
- 2021
-
Ingår i: Ecological Engineering. - : Elsevier. - 0925-8574 .- 1872-6992. ; 160
-
Tidskriftsartikel (refereegranskat)abstract
- Structures for guiding fish around migration barriers are frequently used for maintaining connectivity in regulated riverine systems. However, for non-physical barriers, experimental studies providing direct and detailed observations of fish–barrier interactions in rivers are largely lacking. In this study, we quantify the efficiency of bubble barriers (alone or in combination with light stimuli, and in both daylight and darkness) for diverting downstream migrating Atlantic salmon (Salmo salar). Both a laboratory-based migration experiment and a large-scale field experiment in a regulated river were used to evaluate efficiency of bubble barriers. In the latter, we used acoustic telemetry to provide in situ measurements of how downstream migrating Atlantic salmon smolts interact with bubble barriers. We show that bubbles divert smolts with high efficiency in both a laboratory flume (95%) and in natural settings (90%). This latter efficiency is higher compared to an already present physical barrier (46%) covering the upper two meters of the water column in the large river. The bubble barrier did not affect flume migration in darkness, suggesting that visual cues are crucial for the observed repelling effect of bubbles. We conclude that bubble barriers can be effective, largely maintenance free and low-cost alternatives to physical structures currently used to divert salmon away from high-mortality passages.
|
|
| 37. |
- Leander, Johan, 1988-
(författare)
-
Downstream migration of salmonids in regulated rivers : Non-conventional methods for fish diversion
- 2021
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Passages through hydropower plants can be fatal for downstream migrating salmonids (Salmo spp.). This is particularly true for large adults that are returning to the ocean after spawning. Physicalstructures such as racks can be used to guide fish towards fishways that sidestep high-mortality passages through turbines, but these structures are often too logistically challenging and economically burdensome to deploy at large scales. If functional, non-physical guidance structures, such as bubble barriers, could prove important for salmonid populations in regulated rivers, as they represent a low cost alternative that could also be deployed in larger rivers. This thesis aims to: i) quantify the diverting effect of bubble barriers on downstream migrating salmonids; and ii) disentangle the different sensory cues and behavioral traits that give rise to this potential diversion effect. My experiments showed a strong repelling effect of bubble barriers on downstream migrating Atlantic salmon (Salmo salar) in multiple contexts, ranging from laboratory flumes to 50-100 m long barriers deployed in a regulated river. My field experiments showed that bubble barriers can successfully guide both juveniles (smolts) and adults (kelts) of Atlantic salmon and sea run brown trout (Salmo trutta) at discharges exceeding 500 m3 s-1. The relative fish guidance efficiency ranged from 28% to 86%,and was negative correlated with water velocity. Based on laboratory flume experiments, adding stroboscopic lights reduced the guiding efficiency of the barrier, and interestingly, the repelling effect disappeared entirely when evaluated in darkness. These findings strongly suggest that visual cues are crucial for the repelling effect of bubble barriers. I subsequently hypothesized that the visual appearance of bubbles barriers might be perceived as an area associated with risk for fish, suggesting that more bold and active individuals could be more likely to pass through. However, I found no correlation between the probability of being successfully diverted by a bubble barrier and various proxies for bold behavior or swimming activity. To the contrary, I found that less active salmon parr were more likely to pass through bubbles than the more active smolt. I conclude that bubble barriers can be used to divert downstream migrating salmonids towards safe fishways in regulated rivers. While the guiding efficiency might be lower than for fine sized racks, bubble barriers remain functional at larger scales and across a range of water velocities relevant for most regulated rivers. Hence, bubble barriers represent a largely maintenance free, and low-cost alternative to conventional physical structures, and show great promise as a future management tool to facilitate successful fish migration in regulated river systems.
|
|
| 38. |
- Leander, Johan, et al.
(författare)
-
Guiding downstream migrating Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) of different life stages in a large river using bubbles
- 2024
-
Ingår i: Rivers Research and Applications. - : John Wiley & Sons. - 1535-1459 .- 1535-1467. ; 40:1, s. 107-115
-
Tidskriftsartikel (refereegranskat)abstract
- Salmonid repeat spawners are precious individuals for wild populations due to their high fecundity and previous spawning experience, making them important in environmental policy. However, repeat spawners rarely exist above hydropower dams in regulated rivers as the mortality of post-spawners (kelts) when passing through turbines during downstream migration is very high. To mitigate this problem, there are different technical solutions that potentially guide fish toward available fishways. Bubble barriers represent one alternative to costly physical guiding structures, but the efficiency of bubbles for guiding downstream migrating kelts has not been tested. In this study, we evaluate a 100 m long bubble barrier in guiding salmonids—both smolts and kelts—away from the main current and toward an alternative fishway in Ume River, a large regulated river in northern Sweden. We used both acoustic telemetry and sonar to measure the guiding effect of the bubble barrier for downstream migrating fish. We found that more than twice as many salmonids chose the alternative fishway when the bubble barrier was turned on. This was true both for smolts and kelts, suggesting that bubble barriers can be used to guide salmonids of different life stages in rivers with flow rates over 500 m3 s−1. Indeed, our study indicates that bubble barriers are low-cost structures that could be rapidly applied in many regulated rivers to support salmonid migration.
|
|
| 39. |
- Leander, Johan, et al.
(författare)
-
The old and the new : evaluating performance of acoustic telemetry systems in tracking migrating Atlantic salmon (Salmo salar) smolt and European eel (Anguilla anguilla) around hydropower facilities
- 2020
-
Ingår i: Canadian Journal of Fisheries and Aquatic Sciences. - : Canadian Science Publishing. - 0706-652X .- 1205-7533. ; 77:1, s. 177-187
-
Tidskriftsartikel (refereegranskat)abstract
- Acoustic telemetry represents the state-of-the-art technology for monitoring behaviour of aquatic organisms in the wild. Yet, the performance of different systems is rarely evaluated across species and environments. In this study, we evaluate two different acoustic telemetry systems, a commonly used analogue pulse-position-modulation-based system (VEMCO PPM) and a newly developed high-residency digital binary phase shift key-based system (VEMCO HR2), in ability to track downstream migrating Atlantic salmon smolt (Salmo salar) and European eel (Anguilla anguilla) around hydropower facilities. High-precision GPS were used to evaluate precision and accuracy of hyperbolically positioned data derived from each system. The PPM-based system had higher detection range than HR2 and generated more positions per transmission for eels migrating close to bottom than for surface-oriented salmon smolts. HR2 generated tenfold more positions per time unit than PPM, were less sensitive to noise, achieved submetre positional precision, and were considerably more accurate than PPM-derived positions after filtering. HR2 was deemed more capable than PPM in fine-scale positioning at moderate distances at hydropower facilities.
|
|
| 40. |
- Lucas, Richard, et al.
(författare)
-
A meta-analysis of the effects of nitrogen additions on base cations : Implications for plants, soils, and streams
- 2011
-
Ingår i: Forest Ecology and Management. - : Elsevier. - 0378-1127 .- 1872-7042. ; 262:2, s. 95-104
-
Forskningsöversikt (refereegranskat)abstract
- The dominant base cations (BC: i.e., Ca(2+), Mg(2+), K(+), and Na(+)) are important in buffering soil and water acidity in both terrestrial and aquatic ecosystems. Ca(2+)., Mg(2+), and K(+) are also important in many plant physiological functions. Because BC availability is affected by changes in the nitrogen (N) cycle, we conducted a meta-analysis of previously published data to determine if N fertilization alters the availability of BC in terrestrial and stream ecosystems across biomes. We include data from 107 independent studies published in 62 different articles, taking a holistic perspective on BC by examining their responses to added N in plant foliage, bulk soil, soil solution, and stream water. Our results suggest N fertilization may accelerate BC loss from terrestrial ecosystems over time periods less than five years. We found that N additions resulted in an overall 24% decrease in the availability of exchangeable Ca(2+), Mg(2+), and K(+) in the bulk soil of boreal forest, temperate forest, and grassland biomes. Collectively, responses of BC in boreal forest, temperate forest, tropical forest, and grassland biomes increased following N fertilization by about 71% in soil solution and 48% in stream waters. Additionally, BC responses in foliage decreased in boreal forest and temperate forest biomes following N additions over time periods less than five years, but there were no significant changes over longer time periods. Despite large short-term shifts in BC responses following N additions, we did not find evidence of widespread negative impacts on ecosystems over time periods greater than five years. This analysis suggests effects of N addition on the availability of exchangeable BC may diminish over time. Although the effects on BC can be substantial over periods less than five years, there is little available evidence that N fertilization has had large-scale detrimental effects on the availability of BC needed for plant growth within terrestrial or aquatic ecosystems.
|
|
| 41. |
- Lundin, Erik, 1982-, et al.
(författare)
-
Strong climate impact on the carbon emission – burial balance inhigh latitude lakes
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- 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
|
|
| 42. |
- McCallum, Erin, et al.
(författare)
-
Investigating tissue bioconcentration and the behavioural effects of two pharmaceutical pollutants on sea trout (Salmo trutta) in the laboratory and field
- 2019
-
Ingår i: Aquatic Toxicology. - : Elsevier. - 0166-445X .- 1879-1514. ; 207, s. 170-178
-
Tidskriftsartikel (refereegranskat)abstract
- Pharmaceuticals entering aquatic ecosystems via wastewater effluents are of increasing concern for wild animals. Because some pharmaceuticals are designed to modulate human behaviour, measuring the impacts of exposure to pharmaceuticals on fish behaviour has become a valuable endpoint. While laboratory studies have shown that pharmaceuticals can affect fish behaviour, there is a lack of understanding if behaviour is similarly affected in natural environments. Here, we exposed sea trout (Salmo trutta) smolts to two concentrations of two pharmaceutical pollutants often detected in surface waters: temazepam (a benzodiazepine, anxiolytic) or irbesartan (an angiotensin II receptor blocker, anti-hypertensive). We tested the hypothesis that changes to behavioural traits (anxiety and activity) measured in laboratory trials following exposure are predictive of behaviour in the natural environment (downstream migration). Measures of anxiety and activity in the laboratory assay did not vary with temazepam treatment, but temazepam-exposed fish began migrating faster in the field. Activity in the laboratory assay did predict overall migration speed in the field. In contrast to temazepam, we found that irbesartan exposure did not affect behaviour in the laboratory, field, or the relationship between the two end-points. However, irbesartan was also not readily taken up into fish tissue (i.e. below detection levels in the muscle tissue), while temazepam bioconcentrated (bioconcentration factor 7.68) rapidly (t(1/2) < 24 h). Our findings add to a growing literature showing that benzodiazepine pollutants can modulate fish behaviour and that laboratory assays may be less sensitive at detecting the effects of pollutants compared to measuring effects in natural settings. Therefore, we underscore the importance of measuring behavioural effects in the natural environment.
|
|
| 43. |
- Morlock, Marina A., et al.
(författare)
-
Erosion regime controls sediment environmental DNA-based community reconstruction
- 2023
-
Ingår i: Environmental DNA. - : John Wiley & Sons. - 2637-4943. ; 5:6, s. 1393-1404
-
Tidskriftsartikel (refereegranskat)abstract
- Analysis of environmental DNA detected in lake sediments shows promise to become a great paleoecological technique that can provide detailed information about organism communities living in past environments. However, when interpreting sedimentary environmental DNA records, it is of crucial importance to separate ecosystem responses to large-scale environmental change from “noise” caused by changes in sediment provenance or potential post-depositional DNA mobility. In this study, we show that plant and mammalian communities reconstructed from sediments are strongly affected by sediment provenance, but unaffected by vertical mobility of DNA after sediment deposition. We observe that DNA from aquatic plants was abundant in background sediment, while embedded detrital event layers (sediment deposited under erosion events) primarily contained terrestrial plants; hence, vertical mobility of aquatic plant DNA across sediment layers was negligible within our studied lakes. About 33% of the identified terrestrial plant genera were only found in detrital sediment, suggesting that sediment origin had a strong impact on the reconstructed plant community. Similarly, DNA of some mammalian taxa (Capra hircus, Ursus arctos, Lepus, and Felis) were only or preferentially found in detrital event layers. Temporal changes across the Holocene were the main drivers of change for reconstructed plant communities, but sediment type was the second most important factor of variance. Our results highlight that erosion and sediment provenance need to be considered when reconstructing past mammalian and plant communities using environmental DNA from lake sediments.
|
|
| 44. |
- Nota, Kevin, 1993-, et al.
(författare)
-
Norway spruce postglacial recolonization of Fennoscandia
- 2022
-
Ingår i: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 13:1
-
Tidskriftsartikel (refereegranskat)abstract
- Contrasting theories exist regarding how Norway spruce (Picea abies) recolonized Fennoscandia after the last glaciation and both early Holocene establishments from western microrefugia and late Holocene colonization from the east have been postulated. Here, we show that Norway spruce was present in southern Fennoscandia as early as 14.7 ± 0.1 cal. kyr BP and that the millennia-old clonal spruce trees present today in central Sweden likely arrived with an early Holocene migration from the east. Our findings are based on ancient sedimentary DNA from multiple European sites (N = 15) combined with nuclear and mitochondrial DNA analysis of ancient clonal (N = 135) and contemporary spruce forest trees (N = 129) from central Sweden. Our other findings imply that Norway spruce was present shortly after deglaciation at the margins of the Scandinavian Ice Sheet, and support previously disputed finds of pollen in southern Sweden claiming spruce establishment during the Lateglacial.
|
|
| 45. |
- Olid, Carolina, 1981-, et al.
(författare)
-
Decade of experimental permafrost thaw reduces turnover of young carbon and increases losses of old carbon, without affecting the net carbon balance
- 2020
-
Ingår i: Global Change Biology. - : John Wiley & Sons. - 1354-1013 .- 1365-2486. ; 26:10, s. 5886-5898
-
Tidskriftsartikel (refereegranskat)abstract
- Thicker snowpacks and their insulation effects cause winter-warming and invoke thaw of permafrost ecosystems. Temperature-dependent decomposition of previously frozen carbon (C) is currently considered one of the strongest feedbacks between the Arctic and the climate system, but the direction and magnitude of the net C balance remains uncertain. This is because winter effects are rarely integrated with C fluxes during the snow-free season and because predicting the net C balance from both surface processes and thawing deep layers remains challenging. In this study, we quantified changes in the long-term net C balance (net ecosystem production) in a subarctic peat plateau subjected to 10 years of experimental winter-warming. By combining(210)Pb and(14)Cdating of peat cores with peat growth models, we investigated thawing effects on year-round primary production and C losses through respiration and leaching from both shallow and deep peat layers. Winter-warming and permafrost thaw had no effect on the net C balance, but strongly affected gross C fluxes. Carbon losses through decomposition from the upper peat were reduced as thawing of permafrost induced surface subsidence and subsequent waterlogging. However, primary production was also reduced likely due to a strong decline in bryophytes cover while losses from the old C pool almost tripled, caused by the deepened active layer. Our findings highlight the need to estimate long-term responses of whole-year production and decomposition processes to thawing, both in shallow and deep soil layers, as they may contrast and lead to unexpected net effects on permafrost C storage.
|
|
| 46. |
- Pascual, Didac, et al.
(författare)
-
The missing pieces for better future predictions in subarctic ecosystems: A Torneträsk case study
- 2021
-
Ingår i: Ambio. - : Springer. - 0044-7447 .- 1654-7209. ; 50:2, s. 375-392
-
Forskningsöversikt (refereegranskat)abstract
- Arctic and subarctic ecosystems are experiencing substantial changes in hydrology, vegetation, permafrost conditions, and carbon cycling, in response to climatic change and other anthropogenic drivers, and these changes are likely to continue over this century. The total magnitude of these changes results from multiple interactions among these drivers. Field measurements can address the overall responses to different changing drivers, but are less capable of quantifying the interactions among them. Currently, a comprehensive assessment of the drivers of ecosystem changes, and the magnitude of their direct and indirect impacts on subarctic ecosystems, is missing. The Torneträsk area, in the Swedish subarctic, has an unrivalled history of environmental observation over 100 years, and is one of the most studied sites in the Arctic. In this study, we summarize and rank the drivers of ecosystem change in the Torneträsk area, and propose research priorities identified, by expert assessment, to improve predictions of ecosystem changes. The research priorities identified include understanding impacts on ecosystems brought on by altered frequency and intensity of winter warming events, evapotranspiration rates, rainfall, duration of snow cover and lake-ice, changed soil moisture, and droughts. This case study can help us understand the ongoing ecosystem changes occurring in the Torneträsk area, and contribute to improve predictions of future ecosystem changes at a larger scale. This understanding will provide the basis for the future mitigation and adaptation plans needed in a changing climate.
|
|
| 47. |
- Phillips, Helen R. P., et al.
(författare)
-
Global distribution of earthworm diversity
- 2019
-
Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 366:6464, s. 480-
-
Tidskriftsartikel (refereegranskat)abstract
- Soil organisms, including earthworms, are a key component of terrestrial ecosystems. However, little is known about their diversity, their distribution, and the threats affecting them. We compiled a global dataset of sampled earthworm communities from 6928 sites in 57 countries as a basis for predicting patterns in earthworm diversity, abundance, and biomass. We found that local species richness and abundance typically peaked at higher latitudes, displaying patterns opposite to those observed in aboveground organisms. However, high species dissimilarity across tropical locations may cause diversity across the entirety of the tropics to be higher than elsewhere. Climate variables were found to be more important in shaping earthworm communities than soil properties or habitat cover. These findings suggest that climate change may have serious implications for earthworm communities and for the functions they provide.
|
|
| 48. |
- Rodriguez, Alvaro, et al.
(författare)
-
Refining particle positions using circular symmetry
- 2017
-
Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 12:4
-
Tidskriftsartikel (refereegranskat)abstract
- Particle and object tracking is gaining attention in industrial applications and is commonly applied in: colloidal, biophysical, ecological, and micro-fluidic research. Reliable tracking information is heavily dependent on the system under study and algorithms that correctly determine particle position between images. However, in a real environmental context with the presence of noise including particular or dissolved matter in water, and low and fluctuating light conditions, many algorithms fail to obtain reliable information. We propose a new algorithm, the Circular Symmetry algorithm (C-Sym), for detecting the position of a circular particle with high accuracy and precision in noisy conditions. The algorithm takes advantage of the spatial symmetry of the particle allowing for subpixel accuracy. We compare the proposed algorithm with four different methods using both synthetic and experimental datasets. The results show that C-Sym is the most accurate and precise algorithm when tracking micro-particles in all tested conditions and it has the potential for use in applications including tracking biota in their environment.
|
|
| 49. |
- Rodriguez, Alvaro, et al.
(författare)
-
ToxTrac : a fast and robust software for tracking organisms
- 2018
-
Ingår i: Methods in Ecology and Evolution. - : British Ecological Society. - 2041-210X. ; 9:3, s. 460-464
-
Tidskriftsartikel (refereegranskat)abstract
- 1. Behavioral analysis based on video recording is becoming increasingly popular within research fields such as; ecology, medicine, ecotoxicology, and toxicology. However, the programs available to analyze the data, which are; free of cost, user-friendly, versatile, robust, fast and provide reliable statistics for different organisms (invertebrates, vertebrates and mammals) are significantly limited.2. We present an automated open-source executable software (ToxTrac) for image-based tracking that can simultaneously handle several organisms monitored in a laboratory environment. We compare the performance of ToxTrac with current accessible programs on the web.3. The main advantages of ToxTrac are: i) no specific knowledge of the geometry of the tracked bodies is needed; ii) processing speed, ToxTrac can operate at a rate >25 frames per second in HD videos using modern computers; iii) simultaneous tracking of multiple organisms in multiple arenas; iv) integrated distortion correction and camera calibration; v) robust against false positives; vi) preservation of individual identification; vii) useful statistics and heat maps in real scale are exported in image, text and excel formats.4. ToxTrac can be used for high speed tracking of insects, fish, rodents or other species, and provides useful locomotor information in animal behavior experiments. Download ToxTrac here: https://toxtrac.sourceforge.io (Current version v2.61).
|
|
| 50. |
- Rodriguez-Martinez, Saul, et al.
(författare)
-
The topological nature of tag jumping in environmental DNA metabarcoding studies
- 2023
-
Ingår i: Molecular Ecology Resources. - : John Wiley & Sons. - 1755-098X .- 1755-0998. ; 23:3, s. 621-631
-
Tidskriftsartikel (refereegranskat)abstract
- Metabarcoding of environmental DNA constitutes a state-of-the-art tool for environmental studies. One fundamental principle implicit in most metabarcoding studies is that individual sample amplicons can still be identified after being pooled with others—based on their unique combinations of tags—during the so-called demultiplexing step that follows sequencing. Nevertheless, it has been recognized that tags can sometimes be changed (i.e., tag jumping), which ultimately leads to sample crosstalk. Here, using four DNA metabarcoding data sets derived from the analysis of soils and sediments, we show that tag jumping follows very specific and systematic patterns. Specifically, we find a strong correlation between the number of reads in blank samples and their topological position in the tag matrix (described by vertical and horizontal vectors). This observed spatial pattern of artefactual sequences could be explained by polymerase activity, which leads to the exchange of the 3′ tag of single stranded tagged sequences through the formation of heteroduplexes with mixed barcodes. Importantly, tag jumping substantially distorted our data sets—despite our use of methods suggested to minimize this error. We developed a topological model to estimate the noise based on the counts in our blanks, which suggested that 40%–80% of the taxa in our soil and sedimentary samples were likely false positives introduced through tag jumping. We highlight that the amount of false positive detections caused by tag jumping strongly biased our community analyses.
|
|
