South-central Sweden Research Articles

Seasonal fat content fluctuations in a gyrinid beetle: comparison between an arctic and a temperate zone population (Coleoptera: Gyrinidae)

Seasonal fluctuations in fat content (percentage of dry body weight) of adult Gyrinus opacus were compared between a lake population at the northern range limit of the species in Greenland (G) and a rock pool population in south-central Sweden (S) near its southern range limit. From equally low values at emergence in summer, beetles of both populations accumulated substantial fat reserves, especially during their first weeks as adults. Hardened S-beetles were fatter than G-beetles at time of onset of hibernation. For late emerging (soft) G-beetles, however, the situation was severe because of an immediate freeze-up of the lake. There was a similar winter fat decline in both populations. During the first month after hibernation there was a significant decrease in fat content of the S-beetles, because they were still utilizing their fat deposits from the previous autumn. This trend was broken at the first emergence peak of chironomids in spring. Hibernating G-beetles used their lesser fat storage to the same extent, and led to some reproductive females reaching extremely low levels of fat. Still lower fat content and smaller body size of beetles in a closely situated small lake to G in early spring shows a between locality variation related to differences in habitat quality at the northern range limit.

An evaluation of land suitability for forest fertilization with biofuel ash on organic soils in Sweden

The nutrients removed from the forest when branches and tree tops are harvested for fuel can be returned to the site by bringing back the wood-ash from the burning. In Sweden, this compensation measure is not carried out to any appreciable extent, mostly because there is no economic incentive to the landowner. The ash contains all the elements required for tree growth except for nitrogen (N), the most important element limiting growth on mineral soils. Since ash, so far, is brought back only to mineral soils, increased forest growth cannot be expected. In contrast, for organic soils, N is often abundant whereas the amounts of other mineral nutrients in peat are small. This means that the peatland forests provide an opportunity for ash amendment in order to increase forest production. Old fertilization trials using wood-ash show that the growth increase can be very large. The aims of this study were (i) to calculate the area of peat-covered land that, with respect to stand growth responses, could be regarded as most suitable for biofuel ash (wood-ash and peat-ash) fertilization and (ii) to assess the amount of biofuel ash needed for fertilizing this area. Most of the area calculations were based on data from the Swedish National Forest Inventory (SNFI) 1997–2001. Sites were selected using existing knowledge about ash fertilization effects on tree growth and with the aid of registrations made in SNFI regarding peat thickness, site productivity, drainage, condition of drains, dominating field vegetation, and stage of stand development. Additional calculations were made to estimate the area of abandoned peat harvesting fields ready for after-use by afforestation. According to the selection criteria used, the most suitable sites for biofuel ash fertilization are drained, mid-rotation or old peatland forests where the field vegetation is dominated by shrubs or low sedge plants indicative of medium-low site productivity. The selected area comprises 190,000 ha. Most are located in North and North Central Sweden (90,000 ha), whereas South Central and South Sweden accounted for 30,000 and 70,000 ha, respectively (Figs. 1 and 2). To these areas, 2000–3000 ha of abandoned peat fields ready for afforestation should be available within a period of about 5 years. The present annual production of biofuel ash in Sweden, of acceptable quality for forest fertilization, is 250,000–300,000 tonnes. If it were desired to fertilize all the sites (190,000 ha) identified in this study with 5000 kg per ha, it would require 3–4 years of the current annual production of bio-ash.

Regional and local patterns of peat humification in three raised peat bogs in Värmland, south-central Sweden

Peat humification in five cores from three ombrotrophic bogs in Värmland, south-central Sweden, was analysed in an attempt to investigate local and regional responses to climate changes during the Holocene. The chronology of the five peat sequences was constrained by means of AMS radiocarbon dates and tephrochronology. Four tephras were geochemically correlated with the Askja AD 1875, Hekla-3, Kebister and Hekla-4 tephras. A further tephra, the Stömyren tephra, dated by interpolation to 2200–2100 cal yr BP was found in one bog. A composite record of peat humification changes show several periods of wetter bog conditions. These occur during the later part of the Holocene, corresponding to known climate changes in the North Atlantic region, especially around 4500–4000, 3700–3200, 3000–2700 and 1700–700 cal yr BP. Wet shifts are inferred from individual peat cores and the composite record at c. 5500, 4200, 3700, 3500, 2900, 1700, 850, 650, 500 and 250 cal yr BP. Development of composite records could be a powerful tool to smooth the palaeohydrological records in order to reduce the influence of local fluctuations in the proxy data and to extract the regional climatic signal.

Statistical precipitation downscaling in central Sweden with the analogue method

Most climate predictions show significant consequences globally and regionally, but many of its critical impacts will occur at sub-regional and local scales. Downscaling methods are, thus, needed to assess effects of large-scale atmospheric circulation on local parameters such as precipitation and runoff. This study aims at evaluating the analogue method (AM) as a benchmark method for precipitation downscaling in northern Europe. The predictors used in this study were daily and monthly gridded sea-level pressures from 1960 to 1997 in an area 45–75°N and 30°W–40°E with a resolution of 5×5° long-lat. Analogues for daily and monthly precipitation at seven precipitation stations in south-central Sweden were established with two techniques, principal-component analysis (PCA) and the Teweles-Wobus score (TWS). The results showed that AM downscaling on both daily and monthly basis was commonly generally much better than a random baseline but depended on the objective function used for assessment; PCA and TWS produced similar results in most cases but TWS was superior in simulating precipitation duration and intensity. Downscaling was improved when seasonality was included and when the SLP field was confined to those geographical areas that contributed most to precipitation in south-central Sweden.

The middle Cambrian Ptychagnostus punctuosus and Goniagnostus nathorsti zones in Västergötland, Sweden

New trilobite discoveries from eight localities in Västergötland, south-central Sweden, demonstrate that the middle Cambrian Ptychagnostus punctuosus and Goniagnostus nathorsti zones are present in most Lower Palaeozoic outcrop areas of Västergötland, though as a thin and impersistent conglomeratic limestone, up to approximately 15 cm thick. These zones have not previously been recognised in Västergötland, except for a thin bed of limestone on Hunneberg.

Effects of Wood Ash Dose and Formulation on Soil Chemistry at Two Coniferous Forest Sites

Harvesting stem biomass from the forest inevitably involves exporting nutrients from the ecosystem. The amount exported is increased when the logging residues are also removed for use as fuel. Recycling of the resulting wood ash has been advocated as a measure to compensate for the nutrient losses and to sustain future forest production. The physical formulation of the wood ash may have an important influence on its effects on soil properties. In this paper, we report effects of two different types of wood ash (one self-hardened and crushed, the other pelleted), with differences in solubility, on soil chemistry in the humus layer and upper 15 cm of the mineral soil, at two coniferous sites in south-central Sweden, 5 yr after their application. The crushed ash was applied at three doses (3, 6 and 9 ton ha−1), while the pelleted ash was applied at only one dose (3 ton ha−1). At both sites the soil was podzolized. The two sites differed with respect to soil conditions, despite being situated only a few kilometers apart. The application of wood ash increased both soil pH and base-cation content in the humus layer at both sites. In the mineral soil, the effects were less pronounced. Treatment effects on soil chemistry did not differ between the two ash formulations. The retention (i.e. the extractable amount of nutrients found in the soil that could be attributed to the ash application) of nutrients varied strongly between the two sites, and K retention (ca. 10%) was generally lower than that of Ca and Mg.

Experiences of the use of riverine nutrient models in stakeholder dialogues

The potential of models to assist in stakeholder dialogues is assessed regarding options for the reduction of riverine nitrogen loads in a 357‐km2 river basin in south central Sweden. Scenarios of remedies based on stakeholders' suggestions were used to stimulate discussions in a panel incorporating farmers, municipality staff, politicians and technical advisers. The farmers perceived the model‐derived discussion material as valuable, although only average conditions at a generic farm were simulated. The panellists demonstrated caution when using regionalized information, but did not request quantitative uncertainty estimates. There was a desire to have phosphorus included in the model‐derived discussion material and to include the impacts of other environmental goals than ‘no eutrophication’. The inclusion of different stakeholder groups in the panel sessions was acknowledged as a way to establish a shared perception of the existing environmental status of the basin and to define the pros and cons of various remedies. This was seen by the panellists as a way to facilitate local implementation of the Water Framework Directive (WFD). Use of model‐stimulated local stakeholder panels is also a way to ensure that involved stakeholders perceive local environmental goals as realistic and acceptable. However, to establish river‐basin stakeholder dialogues as part of the nation‐wide implementation of the WFD directive, it will be necessary to develop a model approach that can be used by local advisers. Perhaps the most critical factor is the moderators' ability to provide an atmosphere of mutual respect between all those involved in contrast to performing one‐way lectures to the participants.

The variation of bedrock quality with increasing ductile deformation

Most of the rocks in Precambrian shield areas have experienced a complex structural and metamorphic evolution, processes which have a strong influence on the bedrock quality. This may vary both on a local and regional scale. The main object of this investigation was to study the variation of the rock mechanical properties at various stages of ductile deformation of an originally isotropic rock. Ten samples from five different localities northeast of Lake Vanern (south central Sweden) were tested, including studded tyre and LA tests, uniaxial compressive strength (UCS), ultrasonic velocity, electrical resistivity, Swedish impact value and Swedish flakiness index as well as petrographic and chemical analyses. This study highlights the importance of considering all possible variations in bedrock before classification, and of undertaking regional investigations.

An assessment of twentieth century tree-cover changes on a southern Swedish peatland combining dendrochronoloy and aerial photograph analysis

In the twentieth century, there have been increases in Scots pine (Pinus sylvestris) coverage on peatlands in southern Sweden. In order to assess possible links to contemporary climate change, aerial photograph analysis and dendrochronology were combined to study recent pine cover changes at Anebymossen, a raised peat bog in south central Sweden. Multi-temporal analyses of three sets of panchromatic images from 1950 to 1993 showed a 30% increase of the marginal pine forest of the raised bog during that time, where a significant increase had occurred in the eastern part. Dendrochronological analyses were performed in two parts: the eastern part and the western part where the increase in pine coverage was considerably lower. The tree-ring growth patterns disclosed that a major event, most likely drainage, had occurred at Anebymossen in 1927, affecting tree growth at both sites. The effect of the drainage, which lowers the local ground-water table and hence promotes tree growth, was growth surges with a doubling of the annual increment rates. The effect was short lived in the western part, but continuous drainage in the eastern part caused growth enhancement until the beginning of the 1980s. We suggest that rather than being caused by climate change, the increase in pine coverage on Anebymossen was initiated by the considerable drainage in 1927. Since most peatlands in southern Sweden have been affected by anthropogenic activities, we suggest that it is difficult to make climatological interpretations of tree cover changes on peatlands using only aerial photograph analyses.

Relationship between illness-associated absence in day-care children and weather parameters

This 5-year study demonstrated a statistically significant correlation between morbidity among children attending day-care centres and various weather parameters. The study was undertaken in south-central Sweden, where sharp seasonal contrasts in climatic and weather conditions occur. Illness-associated absence (IAA) decreased significantly when the weather was bright, sunny and warm, determined using average monthly weather parameters analysed over 60 months. This may be because good weather encourages outdoor activities which, in turn, reduce the risk of spreading respiratory tract infections as outdoor play areas are larger, body contact is less frequent, and any bacteria and viruses present will be readily dispersed. In multiple regression analysis, outdoor temperature was the most prominent parameter linked with IAA. This may reflect the behaviour of the staff with regard to various weather conditions. It is therefore to be recommended that children attending day-care centres should be allowed and encouraged to play outdoors when conditions allow.

Genetic diversity assessed by amplified fragment length polymorphism analysis of the parasitic nematode Dictyocaulus viviparus the lungworm of cattle

We have examined the population genetic structure in a collection of nine isolates of the parasitic lungworm Dictyocaulus viviparus. Eight of the isolates were sampled from cattle in geographically separated farms throughout south-central Sweden, and one isolate was a laboratory strain that has been maintained in experimentally infected calves for almost four decades. A total of 72 worms were examined, with eight individual worms from the same individual host representing each isolate. The genetic variation as revealed by amplified fragment length polymorphism analysis using four selective primer combinations was high. Depending on the primer combination a total of 66–79 restriction fragments were amplified, with 26–44 peaks of similar complexity from each of the isolates. The heterozygosity within populations was relatively small, as were the population mutation and immigration rates, which seemed to be in neutral equilibrium. The genetic diversity was therefore reasonably well structured in the field; and the laboratory isolate was quite distinct from the field samples. There was no relationship between the patterns of genetic diversity and the geographical proximity of the farms. The estimates of heterozygosity were much larger and more consistent than those previously estimated for this nematode species using mitochondrial sequencing, and the genetic structuring was thus much less pronounced and the gene flow greater. We attribute these differences in estimation to the broader sampling of loci available using amplified fragment length polymorphism markers, which may therefore constitute a superior technique for the study of patterns of lungworm diversity. Furthemore, the data estimating gene flow for D. viviparus was less than previously reported for closely related species in North America. This might be related to different rates of movements of infected hosts. It seems likely that lungworm infections are rather persistent on different farms, and the sudden outbreaks of disease that can be observed with host movements are most likely to be related to the introduction of susceptible stock.

Increased Nitrification in Acid Coniferous Forest Soil Due to High Nitrogen Deposition and Liming

This study investigated whether liming stimulates the potential nitrification of acid forest soils in southern Sweden, and whether such stimulation (if present) is more pronounced in areas receiving high nitrogen (N) deposition. A short-term (30 h) soil-slurry incubation technique was used, which reduces the risk of bacterial growth, nitrate immobilization and denitrification during the incubation. The nitrate and nitrite produced were measured after biological conversion to nitrous oxide. The investigation was performed 6–7 yrs after the liming at four coniferous forest sites in the central and western parts of southern Sweden, which receive low and high deposition of N, respectively. Overall, liming had increased pH significantly down to 10 cm soil depth, but at 20 cm depth there was no difference between the limed and non-limed soil. In cases when liming had affected the total N pool and the potential nitrification, this was also limited to the uppermost 10 cm. It seems likely that the effects of liming on the potential nitrification were dependent on N availability, which is in turn influenced by N mineralization, trees’ demands for N, and atmospheric N inputs. The strongest stimulatory effect of liming on the potential nitrification was seen on the west coast, indicating that these sites had the highest availability of ammonia for nitrifiers. However, liming also increased nitrification at one of the sites in south–central Sweden, which could have been mediated by increased rates of N mineralization.

Mineralogy and parageneses of Pb oxychlorides in Långban-type deposits, Bergslagen, Sweden

The Pb oxychlorides comprise a group of rare minerals occurring as fissure and vein fillings in Palaeoproterozoic Långban-type Mn-Fe oxide deposits within the Bergslagen ore province, south central Sweden. Ecdemite, heliophyllite, sahlinite and nadorite occur at Harstigen; sahlinite at Jakobsberg, and all these as well as blixite, freedite, mendipite, perite and sundiusite occur at Långban. However, the presence of heliophyllite at Långban is ambiguous. Typical assemblages include ubiquitous calcite and baryte, and minor native metals, hydrocerussite, arsenites, arsenates and silicates. Electron microprobe analyses of a selection of Pb oxychloride minerals from these deposits are presented. These data indicate substitution between Sb3+ and As3+ in the ecdemite (-heliophyllite) and nadorite-type oxychloride structures. Furthermore, the composition of blixite is variable; empirically it varies between c. Pb4O3Cl2 and Pb2O(OH)Cl. The Pb oxychloride assemblages occur in two main textural positions: 1) in partly open fissures or druses, and 2) intergrown in veins or schlieren. Textural and paragenetic observations suggest that the oxychlorides formed at two main stages; firstly associated with metamorphism of the host rocks; secondly at lower P and T during post-metamorphic brittle tectonic conditions. Alteration of oxychlorides may lead to formation of native lead, litharge, hedyphane, Pb carbonates, nadorite and a finnemanite-like phase. The dominant fissure and vein host rocks comprise Fe-Mn-oxide ores or oxide±silicate-bearing carbonate rocks and Fe-Mn skarn rocks. Most of the required metals were probably sequestered from the local host rocks. It is suggested that the fissure-hosted oxychloride assemblages formed primarily from saline aqueous solutions at low pressures and temperatures.

Holocene humidity fluctuations in Sweden inferred from dendrochronology and peat stratigraphy

Tree‐ring and peat stratigraphy data were examined back to 5000 BC in order to identify and compare humidity changes in Fennoscandia. The temporal variation in distribution of Scots pine (Pinus sylvestris L.) was used as a measure of past lake‐level fluctuations in central Sweden. The chronology, which spans 2893 BC–AD 1998 with minor gaps in AD 887–907 and 1633–1650 BC and with additional floating chronologies back to 4868 BC, was cross‐dated and fixed to an absolute timescale using a chronology from Torneträsk, northern Sweden. The peat stratigraphy from the Stömyren peat bog, south‐central Sweden, was transformed into humification indices to evaluate humidity changes during the past 8000 years. The peat chronology is established by four tephra datings and eight 14C datings. Synchronous periods of drier conditions, interpreted from regeneration and the mortality pattern of pine, tree‐ring chronology and peat humification, were recognized at c. 4900–4800 BC, 2400–2200 BC, 2100–1800 BC, 1500–1100 BC, AD 50–200, AD 400–600 and AD 1350–1500. Possible wetter periods were encountered at 3600–3400 BC, 3200–2900 BC, 2200–2100 BC, 1700–1500 BC, 1100–900 BC, 100 BC‐AD 50, AD 200–400, AD 750–900 and AD 1550–1700. The wet and dry periods revealed by the tree rings and peat stratigraphy data indicate considerable humidity changes in the Holocene.

Ferro-potassic A-type granites and related rocks in NE Poland and S Lithuania: west of the East European Craton

The present study of monzodiorite, quartz monzodiorite, monzonite, quartz syenite, granodiorite, and rapakivi-like granite surrounding the Suwalki, Ketrzyn and Sejny anorthosite, norite and gabbro plutons or forming separate bodies in northern Poland and southern Lithuania, has resulted in the recognition of a specific suite with AMCG affinity. The bodies belonging to the Mazury and Veisiejai complexes are aligned to E-W trending lineaments in southern Lithuania and northern Poland with a continuation through the Baltic Sea into south-central Sweden in the west and into NW Belarus in the east. The rocks of the suite form a continuous series ranging from 45 to 75% SiO2 with no indication of the classical Daly gap between mafic and felsic rocks. The Mazury and Veisiejai complexes chemically belong to the ferro-potassic alkali-calcic type of rocks and are comparable with the AMCG suite, e.g. in Rogaland, southern Norway. The most acidic varieties of the granitoids approach the classic rapakivi granites in their petrogenetic characteristics, elevated contents of incompatible elements and REE, and hence have A-type affinities. The granitoids are assigned to the ‘Post-collisional Granite’ field. The overall evolution from mafic to acidic rocks is characterized by well-defined trends which most probably represent a liquid line of descent. Fractional crystallization with or without assimilation and hybridization can account for the continuous evolution from mafic to acidic members. The formation of the suite is concentrated in the timespan covering almost 50 Myr from 1.55 to 1.5 Ga. The most felsic rocks yield ages of ca. 1.5 Ga, which are very similar to the Kabeliai granites further east in southeastern Lithuania. Cooling and local mylonitization proceeded until 1.4 Ga (hornblende and biotite 40 Ar/ 39 Ar ages).

Modelling of human and climatic impact on nitrogen load in a Swedish river 1885-1994

Changes in environmental conditions within a river basin in South Central Sweden (1400 km 2 ) and impacts on riverine nitrogen (N) transport were evaluated. A historical database was compiled and the process-based HBVN model used to estimate flow normalised N loads in 1885, 1905, 1927, 1956, 1976, and 1994, using a standard climatological record (1985–1994). The study shows the value of process-based modelling in environmental impact assessment, by making it possible to assess and integrate the effect of a number of factors, both with regard to human impact and natural climatic variability. Factors taken into account include: the effects of land use, agricultural practices, atmospheric deposition, human dietary intake, use of flush toilets, lowering of lakes, building of dams, and climatic variability. For all years studied, agriculture was the overriding source of N, and changes in riverine N over time mainly reflected changes in land use and agricultural practices. In spite of decreasing N-leaching from agriculture, the net load remained fairly constant between 1885 and 1927, due to reduced N retention. Drainage of agricultural land had a dominating impact on reducing N retention, which increased the N loads, while the effects of the lowering of lake levels and dam building were less pronounced. Household N emission per capita was higher in 1994 than in 1927, as the increased consumption of meat and dairy products alone resulted in a higher increase of the emission than was compensated for with wastewater treatment improvement. In addition, introduction of flush toilets increased the emission from households. In total, the net load in 1976 was twofold higher than that in 1885, 1905 and 1927, due to increased leaching from agriculture, wastewater emission, and atmospheric deposition on lake surfaces. Finally, the impact of climatological variability was assessed, using a 110-yr climatological record. The choice of 10-yr period of climatological data was the factor that had the largest impact on calculated N load.

Öggestorps åkrar

The Öggestorp area in south central Sweden has been subject to a fair amount of rescue archaeological excavations. It is one of the most excavated parishes in northern Småland. The remains are mostly from the Preroman and Roman Iron Ages. The distinguishing features are graves and agricultural remains. Agricultural remains are notoriously difficult to date in a convincing way. When recently carrying out a major excavation the dating of agricultural remains was one of the focuses. OSL dating of entrapped sediments was carried out with fairly convincing results. Two major phases can be identified in the use of the agricultural remains at Öggestorp. The first was the establishment and primary use in the Preroman and Roman Iron Ages. The second occurs in Medieval times and the Renaissance. A short discussion on the issue of conditions in rescue archaeology with special emphasis on methodological development is also carried out.

Transitioning from Svecofennian to Transcandinavian Igneous Belt (TIB) magmatism in SE Sweden: Implications from the 1.82 Ga Eksjö tonalite

The Eksjö intrusion forms a major tonalitic body in the Oskarshamn-Jönköping belt (OJB), SE Sweden. This is a NW–SE unit of dominantly intermediate granitoid intrusions, bound by felsic rocks of the Transscandinavian Igneous Belt (TIB). Previous U–Pb data for the Eksjö tonalite (1754±10 Ma) implied that subduction-related magmatism occurred in SE Sweden during a period of time when other data required that such magmatism had already moved further west. New U–Pb zircon dating establishes that the Eksjö tonalite crystallised at 1823±2 Ma and that subduction-related, granitoid magmatism of the OJB occurred in the 1834–1823 Ma interval. Field observations and geochemistry implies fractional crystallisation in either a continental arc or a mature island arc system. Although major portions of the Eksjö intrusion are well preserved, it is cut by NW-trending shear zones attributed to block-related movements that remained active until at least 1.80 Ga. Available constraints for the OJB support models of recurring convergent-margin tectonism along the southwestern margin of Baltica between 1.85–1.82 Ga and, hence, prior to onset of voluminous TIB 1 magmatism (1.81–1.77 Ga). Such a scenario accounts for recurring deformation in SW Finland (1.84–1.80 Ga), broadly coeval deformation in south-central Sweden, and apparent steps in Moho depths between the OJB and the pre-1.85 Ga margin of Baltica.

Hydrothermal minerals, fluid flow and brittle/semi-brittle deformation: A comparison between the Skyttorp-Vattholma Fault Zone (SVFZ), south-central Sweden and the Iberia Abyssal Plain (ODP Leg 173, Hole 1067)

Hydrothermal minerals, fluid flow and brittle/semi-brittle deformation: A comparison between the Skyttorp-Vattholma Fault Zone (SVFZ), south-central Sweden and the Iberia Abyssal Plain (ODP Leg 173, Hole 1067)

Estimating the natural background atmospheric deposition rate of mercury utilizing ombrotrophic bogs in southern Sweden.

A critical gap in the understanding of the global cycling of mercury is the limited data describing the natural background atmospheric deposition rate of mercury before the advent of pollution. Existing estimates of the natural deposition rate are typically about 2-5 microg of Hg m(-2) year(-1) (see, for example, Swain et al. Science 1992, 257, 784-787), based on studies that generally rely on short, 210Pb-dated lake sediment and peat cores that span the past 150 years. Analyses of mercury in long peat cores in southcentral Sweden indicate that natural mercury deposition rates in the period 4000-500 BP were lower, about 0.5-1 microg of Hg m(-2) year(-1). This suggests that recent mercury accumulation rates in the peat (15-25 microg of Hg m(-2) year(-1)) and measured atmospheric deposition rates of mercury in Sweden over the past 3 decades (5-30 microg of Hg m(-2) year(-1)) (Munthe et al. Water, Air, Soil Pollut.: Focus 2001, 1, 299-310) are at least an order of magnitude greater than the prepollution deposition rate, rather than representing only a 3-5-fold increase, as has generally been estimated.