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| 7. |
- Beylich, A. A., et al.
(författare)
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Intensity and spatio-temporal variability of fluvial sediment transfers in an Arctic-oceanic periglacial environment in northernmost Swedish Lapland (Latnjavagge catchment)
- 2006
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Ingår i: Geomorphology. - : Elsevier BV. - 0169-555X. ; 80:1-2, s. 114-130
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Tidskriftsartikel (refereegranskat)abstract
- Intensity and spatio-temporal variability of fluvial sediment transfers and mechanical fluvial denudation were analyzed in the periglacial Latnjavagge catchment (9 km(2); 950-1440 m a.s.l.; 68.20N, 18.30E) in Arctic-oceanic northernmost Swedish Lapland. The present-day rates of fluvial sediment transfer are low. The mean annual mechanical fluvial denudation rate at the inlet of lake Latnjajaure, as calculated after five years of process monitoring (2000-2004), and excluding a "rare rainfall event" which caused 3.2 times higher suspended sediment transport during one day as compared to the total mean annual suspended sediment transport, is 2.3 t km(-2) yr(-1). In years without "rare rainfall events", most of the total annual sediment load is transported in a. few days during annual snowmelt runoff. In the calculation of longer-term sediment budgets, rare rainfall events like the July 20th-21 st, 2004 event have to be considered as essential components. Reliable estimation of the recurrence intervals of such events is problematic. The pattern of ice patches and snow fields within the valley, the steepness of streams and channels and the location of areas showing slushflow activity are the major factors,controlling spatial variability of mechanical fluvial denudation in the drainage basin. The five lakes in Latnjavagge, especially lake Latnjajaure, are significant sediment traps and ground below 1300 m a.s.l. is protected by a very stable and closed vegetation cover and rhizosphere across the entire lower catchment. (c) 2006 Elsevier B.V. All rights reserved.
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- Beylich, A.A., Kolstrup, E., Thyrsted, T., Linde, N., Pedersen, L.B.
(författare)
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Assessment of chemical denudation rates in cold environments
- 2004
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Ingår i: A handbook of periglacial field methods. - : www.unis.no. ; , s. 18pp-
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Tidskriftsartikel (refereegranskat)
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| 9. |
- Beylich, A. A., et al.
(författare)
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Rates of chemical and mechanical fluvial denudation in an arctic oceanic periglacial environment, latnjavagge drainage basin, northernmost Swedish Lapland
- 2005
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Ingår i: Arctic Antarctic and Alpine Research. - 1523-0430 .- 1938-4246. ; 37:1, s. 75-87
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Tidskriftsartikel (refereegranskat)abstract
- A process geomorphological investigation was started in 1999 to study present denudation rates and the mutual relationship of chemical and mechanical fluvial denudation in periglacial environments. Latnjavagge (9 km(2); 950-1440 in a.s.l.; 68° 20'N, 18° 30'E) was chosen as a representative drainage basin of the arctic-oceanic mountain area in northernmost Swedish Lapland. Atmospheric solute inputs, chemical denudation, and mechanical fluvial denudation were analyzed. During the arctic summer field seasons of 2000, 2001, and 2002 measurements of daily precipitation, solute concentrations in precipitation, and in melted snow cores, taken before snowmelt, were recorded. In addition, solute and suspended sediment concentrations in creeks were analyzed, and bedload tracer movements were registered during the entire summer seasons (end of May until beginning of September). Results show a mean annual chemical denudation net rate of 5.4 t km(-2) yr(-1) in the entire catchment. Chemical denudation in Latnjavagge is less than one third of chemical denudation rates reported for Karkevagge (Swedish Lapland) but seems to be at a similar level as in a number of other subarctic, arctic, and alpine environments. Mechanical fluvial denudation is lower than chemical denudation. Most sediment transport in channels occurs in the early summer season during a few days with snowmelt generated runoff peaks. The main sediment sources in the drainage basin are mobilized channel bed pavements exposing fines, ice patches/fields, and material mobilized by slush flows. The calculated mean mechanical fluvial denudation rate is 2.3 t km(-2) yr(-1) at the inlet of lake Latnjajaure, situated in Latnjavagge close to the outlet of the valley. A very stable vegetation cover and rhyzosphere in this environment mainly explain the low value. The mean mechanical fluvial denudation rate at the outlet of the entire Latnjavagge drainage basin, below lake Latnjajaure, is only 0.8 t km(-2) yr(-1). Both chemical and mechanical fluvial denudation show low intensity. The results from Latnjavagge support the contention that chemical denudation is a somewhat important denudational process in periglacial environments.
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- Nyberg, Rolf, et al.
(författare)
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56 years of solifluction measurements in the Abisko Mountains, northern Sweden- : analysis of temporal and spatial variations of slow soil surface movement
- 2009
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Ingår i: Geografiska Annaler. Series A, Physical Geography. - 0435-3676 .- 1468-0459. ; 91:3, s. 215-232
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Tidskriftsartikel (refereegranskat)abstract
- Solifluction movement rates from 1952 to 2008 for the Abisko region, N Sweden, have been compiled and analysed through correlation tests and multiple regression. It is concluded that movement rates may increase with high mean annual air temperature in the western part of the region, the spatial variability of movement rates within the region is very high and that altitude (and/or permafrost) together with wetness index are the main controls on the regional spatial variation. The study highlights the limitations in establishing statistical relationships between movement rates and climate using data from different field empirical studies
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| 11. |
- Rota, E., et al.
(författare)
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Mitochondrial evidence supports a Nearctic origin for the spreading limicolous earthworm Sparganophilus tamesis Benham, 1892 (Clitellata, Sparganophilidae)
- 2016
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Ingår i: Contributions to Zoology. - : Brill. - 1383-4517 .- 1875-9866. ; 85:1, s. 113-119
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Tidskriftsartikel (refereegranskat)abstract
- We analysed samples of Sparganophilus taken at the corners of its distribution area in Europe (UK, Germany and Italy). No mitochondrial genetic divergence within and amongst them was found, neither in COI nor in 16S. Further, the COI haplotype was also identical to two sequences from Ontario, Canada in the Barcoding of Life Data System (BOLD) database. Our European COI and 16S sequences showed only minimal differentiation (only 1 or 2 substitutions) from specimens newly collected in Illinois and Washington states (USA), as well as from a COI haplotype from Tennessee (USA) in BOLD. An additional COI haplotype from Illinois (found in BOLD) is 2.1% different from the other haplotypes but clearly belongs to the same lineage of Sparganophilus. This geographically broad but genetically compact group fits the morphological diagnosis of S. tamesis Benham, 1892 as revised by Jamieson (1971) and is seen as evidence that all European populations 1) belong to the same species, 2) derive from a recent introduction, 3) are con specific with the most widespread species of Sparganophilus in North America, and that 4) S. tamesis is a senior synonym of S. eiseni Smith, 1895. The single European haplotype does not refute the possibility of its spread from a single introduced source population.
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| 12. |
- Beylich, Achim, A., et al.
(författare)
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Experimental weathering of selected non-calcareous rock types under wet/moist conditions
- 2007
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Ingår i: Zeitschrift für Geomorphologie. - 0372-8854. ; 51:1, s. 1-26
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Tidskriftsartikel (refereegranskat)abstract
- This experiment outlines chemical and physical weathering of selected non-calcareous rock types during the time between November 2002 and February/March 2004. Parallel series of rock specimens were placed in boxes and half covered by water. One set was exposed to different temperature amplitudes in a freeze room, i.e., a simulated periglacial environment, another set was placed outdoor in a temperature environment with a mean annual temperature of c. +6°C, and four samples were placed in an office with a temperature of 21°C ± 3°C throughout. Electric conductivity, ion composition and pH values of the water together with the resulting amount of debris were determined for all samples at the termination of the experiment. In addition the electric conductivity and the debris were noted at intervals during the experiment. All samples experienced chemical weathering and the Freeze room and the Outdoor samples also underwent physical weathering to various extent. Generally speaking the highest degree of physical weathering was found in the Freeze room samples, but the pattern was not consistent. The relative importance of chemical weathering on the other hand seems more related to rock type than to environmental conditions. In single cases there are hints to suggest quantitative dominance of chemical over physical weathering in the Freeze room series. A tentative relationship between weathering of the respective rock types and the landforms in the areas of their origin could be noted. In spite of the low sample number and simple investigation methods the results suggest that rates of chemical and physical weathering as well as their mutual importance is more complex than traditionally believed.
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| 14. |
- Beylich, Achim A., et al.
(författare)
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Selection of critical key test catchments
- 2007
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Ingår i: In: Beylich AA and Warburton J, eds. Analysis of Source-to-Sink-Fluxes and Sediment Budgets in Changing High-Latitude and High-Altitude Cold Environments: SEDIFLUX Manual, First Edition.. - Trondheim : Geological Survey of Norway.
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 16. |
- Holth, T.F., et al.
(författare)
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Genotoxicity of Environmentally Relevant Concentrations of Water-Soluble Oil Components in Cod (Gadus morhua)
- 2009
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 43:9, s. 3329-3334
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Tidskriftsartikel (refereegranskat)abstract
- Large discharges from oil and gas production platforms (produced water) have led to concerns for adverse biological effects in marine areas. The aim of this study was to investigate the development of DNA adduct formation and related biomarkers in fish after chronic exposure to water-soluble components of oil. Atlantic cod (Gadus morhua) were exposed for up to 44 weeks to three treatments (low, pulsed, high) containing environmentally relevant concentrations of low-molecular-weight polycyclic aromatic hydrocarbons (PAHs) and short-chained alkylphenols (APs). A time- and dose-related pattern of DNA adduct formation (measured using P-32-postlabeling) was observed. The results suggested that an extended exposure period (more than 16 weeks) would be required for the formation of DNA adduct levels above background. Interestingly, fish receiving pulsed high exposure did not develop elevated concentrations of DNA adducts, possibly due to DNA repair processes. No obvious relationship between DNA adduct concentration and cytochrome P4501A activity (EROD) was observed. This study has demonstrated the genotoxic potential of water-soluble oil components, relevant for operational discharges (produced water) and chronic oil spills. The quantification of PAH metabolites in bile and hepatic DNA adduct formation appear to be suitable for environmental monitoring of chronic oil pollution
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| 17. |
- Ridefelt, Hanna, et al.
(författare)
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56 years of solifluction measurements in the Abisko mountains, northern Sweden - analysis of temporal and spatial variations of slow soil surface movement
- 2009
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Ingår i: Geografiska Annaler. Series A. Physical Geography. - : Informa UK Limited. - 0435-3676 .- 1468-0459. ; 91A:3, s. 215-232
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Tidskriftsartikel (refereegranskat)abstract
- Solifluction movement rates from 1952 to 2008 for the Abisko region, northern Sweden, have been compiled and analysed through correlation tests and multiple regression. The temporal analysis is based on two datasets (Lobe11 & gridAB and Line B) from Karkevagge. The dataset Lobe11 & gridAB show a strong correlation between movement rates and mean annual air temperature (MAAT) and MAAT is also identified as one of the significant contributing parameters in the multiple regression model. No significant correlations were found for the Line B dataset. The spatial analysis indicates generally higher movement rates in the western part of the region and at lower altitudes mainly between 700 and 900 m a.s.l., but the spatial variability is high. To reduce the influence of the temporal variation the data for the correlation tests of the spatial variations were divided into two parts: 1957 to 1980 and 1981 to 2008. The correlation analysis of the dataset 1957 to 1980 shows a significant negative correlation between annual average movement rates and permafrost probability and altitude. The dataset 1981 to 2008 shows a positive correlation between movement rates and wetness index. It is concluded that movement rates may increase with higher MAAT in the western part of the region (Karkevagge), the spatial variability of movement rates within the region is very high and that altitude (and/or permafrost) together with wetness index are the main controls on the regional spatial variation. The study highlights the limitations in establishing statistical relationships between movement rates and climate using data from different field empirical studies.
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