Southwest Norway Research Articles

What happened in the hinterland?

What happened in the hinterland?
 A batch study of early bucket-shaped pots from the 4th and 5th centuries AD in Southwest Norway

Short-term inflow forecasting in a dam-regulated river in Southwest Norway using causal variational mode decomposition

Climate change affects patterns and uncertainties associated with river water regimes, which significantly impact hydropower generation and reservoir storage operation. Hence, reliable and accurate short-term inflow forecasting is vital to face climate effects better and improve hydropower scheduling performance. This paper proposes a Causal Variational Mode Decomposition (CVD) preprocessing framework for the inflow forecasting problem. CVD is a preprocessing feature selection framework that is built upon multiresolution analysis and causal inference. CVD can reduce computation time while increasing forecasting accuracy by down-selecting the most relevant features to the target value (inflow in a specific location). Moreover, the proposed CVD framework is a complementary step to any machine learning-based forecasting method as it is tested with four different forecasting algorithms in this paper. CVD is validated using actual data from a river system downstream of a hydropower reservoir in the southwest of Norway. The experimental results show that CVD-LSTM reduces forecasting error metric by almost 70% compared with a baseline (scenario 1) and reduces by 25% compared to an LSTM for the same composition of input data (scenario 4).

Reassessing social trust: gossip, self-policing, and Covid-19 risk communication in Norway

This article analyses patterns of compliance with COVID-19 regulations in Southwest Norway. Based on ethnographic fieldwork and a series of interviews, we contrast grassroots discourses with the Norwegian government’s own emphasis on ‘trust’ in its risk communication strategies. As opposed to the official claim that Norwegians complied with COVID-19 emergency regulations because they trusted the authorities, the evidence suggests that citizens complied more due to the informal pressure of their peers. Affective reciprocity and moral judgement, including the dynamics of kinship sociability in which they are expressed, here acquire a critical analytical dimension. In dialogue with dominant theories of trust in risk studies, we argue that such relational aspects of everyday life should be taken into consideration as essential factors for any health risk mitigation strategy.

Timing of spring migration of Norwegian Great Cormorants: long-term trends and effects of winter severity

Migratory birds are showing species-specific responses to climate change through changes in phenology, distribution and abundance. While many bird observatories collect standardised data on migratory passerines to provide invaluable information on changes in their abundances and migratory phenology, some bird observatories also undertake visual observations of passing migratory waterbirds and seabirds. In this study, we use two such long-term datasets of Great Cormorants (Phalacrocorax carbo) compiled during their spring migration. We explore the extent to which winter severity has affected their migration phenology and whether there have been long-term trends in migration timing. Observations were conducted at Lista Bird Observatory in southwest Norway (1992–2020) and at Skagen in north Jutland, Denmark (1974–98). At Skagen, there were no detectable long-term trends in Great Cormorant migratory timing. However, the median date (marking the passage of 50% of birds) was significantly advanced following warm winters. Changes in the date of passage of the first 10% of birds was close to doing so as well, but the late phase (the passage of 90% of birds) showed no relation to temperature. At Lista, winter temperatures in the southern part of the wintering area had no significant effect on the overall timing of the spring passage, but the first 10% of the Cormorants migrated significantly earlier in years with mild late March temperatures at Lista. The early phase of passage at Lista showed a significant long-term trend towards an advancement of migration, leading to an extended migration period. The findings of this study indicate that the timing of Great Cormorant spring migration does in some cases respond to late winter temperatures or show long-term trends, but that the responses and trends differ between sites and between the beginning, middle and late phases of the migration, with the early and middle phases generally showing stronger responses and trends than the late phase.

Bynamnet Stavanger

There has been much discussion about the origin of the city name Stavanger, Old Norse Stafangr, in south-west Norway. There is consensus that the final element is from the Old Norse *angr m., meaning ‘bay’, ‘fjord’ and that the first element is from the Old Norse stafr m. ‘stick’, ‘pole’, however, there are various suggestions regarding what lies behind these words. Some previous interpretations are discussed in this article. Does the first element refer to a special boundary mark, to a steep mountainside or to a bay with a straight formation? Exploring the development of discussions around the name Stavanger is also of interest. These two words appear in several place names in Scandinavia, making studying possible parallels relevant.

Paleomagnetism and 40Ar/39Ar geochronology of Meso-Neoproterozoic rocks from southwest Norway. Implications for magnetic remanence ages and the paleogeography of Baltica in a Rodinia supercontinent context

Here we present new 40Ar/39Ar geochronology, rock magnetic, and paleomagnetic data obtained from rocks from three distinct domains of the Precambrian Sveconorwegian orogen (Southern Norway) that record progressively younger orogenic events from east to west. The first locality is in the Bamble lithotectonic unit and the other two areas are located within the Telemark and Rogaland–Vest Agder sectors in the central and southwestern parts of the Telemark lithotectonic unit, respectively. New and existing geochronology data on metamorphism and cooling, combined with detailed rock magnetic analyses indicate that studied rocks cooled and blocked (acquired) the natural remanent magnetization at ∼ 1090 Ma (Bamble Lithotectonic unit), 1000 Ma (Central Telemark), and at around 900 Ma in the westernmost part of the Telemark Lithotectonic Unit. Accordingly, the new paleomagnetic poles for the Bamble (Plat = -6.6°N, Plong = 218.4°E, N = 38, A95 = 6.1°, K = 15.6), central Telemark (Plat = -17.4° N, Plong = 229.8° E, N = 23. A95 = 6.5 °, K = 22.6), and western Telemark Lithotetonic Unit (Plat = -46.2° N, Plong = 209.4° E, N = 9, A95 = 12.0, K = 19.4) were assigned 1090 Ma, 1000 Ma, and 900 Ma ages, respectively. The new Bamble paleomagnetic pole reconstructs Baltica at ∼ 1090 Ma with noticeable latitudinal gap from the eastern Laurentian margin and thus does not support classical Baltica-Laurentia configuration within the Rodinia supercontinent. The other two younger poles, when used together with the coeval paleomagnetic data from Laurentia do not support the traditionally envisaged Meso- to Neoproterozoic Baltica-Laurentia relationship either. Overall, the new data do not lend any support to the close connection between the two continents during the proposed Rodinia tenure but instead emphasize the problems with the traditional paleogeographic reconstructions of Rodinia. The new data appear more in line with the geological record within the Sveconorwegian orogen, which indicates that the orogeny developed at or behind active continental margins. While Baltica and Laurentia may have resided at broadly similar latitudes between 1000 and 900 Ma, there is no geologic and paleomagnetic evidence for placing them next to each other.

Assessment of the TREELIM model in predicting present treeline along a longitudinal continentality-maritimity gradient in south-western Norway

ABSTRACT Treelines driven by climatic conditions are characteristic of alpine areas. This study assesses the degree of accuracy with which the TREELIM model predicts present treeline elevation along a regional continentality-maritimity gradient in southwest Norway. The study area consists of 15 sites chosen along this gradient, wherein observed treelines range from nearly sea level to over 1200 m a.s.l. The TREELIM model calculates treeline position based solely on meteorological parameters obtained from gridded climate datasets. The model assumes that tree growth occurs if the length of the growing season (LGS) exceeds a minimum duration and the seasonal mean temperature (SMT) does not fall below a certain value. Six different scenarios were developed in order to determine the effects of changing precipitation and drought within TREELIM. Within these scenarios, three different SMTs were used in order to model the treeline position. Model performance was evaluated by comparing resultant treeline elevation with observed values. Results of experiments using lapse rate-based temperature input data were compared to those using the gridded climate data. Statistical analysis determined that the lapse rate-based temperature scenario removing drought constraints and using a SMT of 6.4°C gave the most accurate prediction of treeline position, and a relatively uniform growing season ranging from 110 to 128 days. Precipitation and snow cover do not significantly affect treeline elevation. The results suggest that TREELIM accurately predicts the treeline in most cases, but is less suited in areas with steeply varying topography.

Postglacial relative sea level change in Norway

We present the first comprehensive postglacial relative sea-level (RSL) database for the Norwegian coast from Oslo to the Kola Peninsula. The database spans the last 20 kyrs and is composed of 413 index points and 610 limiting data points derived from raised beaches, archeological data, glaciomarine terraces, and sedimentary indicators from isolation basins, salt marshes, and peat bogs. The data are quality controlled, assigned standardized indicative meanings, and recalibrated to current standards. We use an ensemble of Bayesian statistical models, trained on sea-level index points and weighted by their fit to both index and sea-level limiting points, to assess the spatiotemporal patterns of Norwegian RSL change. Continuous RSL fall driven by isostatic rebound in response to Eurasian ice sheet collapse dominates the RSL signal at every inland location in Norway. A first transgression (episode of RSL rise), which occurred in southwest Norway during the Younger Dryas (14–11.7 ka), increased RSL by as much as 15 m in some locations. A second transgression, named the Tapes transgression, occurred during the early-mid Holocene between 10 and 5.5 ka. The spatiotemporal model ensemble constrains the timing, amplitude, and spatial distribution of the Younger Dryas and Tapes transgressions. Based on our modeling results, we speculate that the Tapes Transgression was the result of global mean sea level rise temporarily outpacing isostasy-driven RSL fall, while the Younger Dryas Transgression was likely the result of local ice sheet readvance combined with low viscosity asthenosphere and weak lithosphere in the region. We also describe the effects of peripheral bulge migration on Norwegian RSL, which caused increased RSL in the early Holocene and a delayed Tapes transgression. We show that postglacial RSL data in Norway contain complex spatiotemporal patterns of nearfield RSL change that can best be estimated by combining a high-quality data compilation with glacial isostatic adjustment modeling via a robust statistical model.

Ambient and experimental warming effects on an alpine bryophyte community

Alpine and Arctic bryophytes have been found to respond negatively to climate change, but as they are often analysed as one functional group, there is limited knowledge on species-specific responses. In this study, we examine how nearly two decades of experimental warming by open-top chambers and ambient warming have affected the bryophyte community structure in an alpine Dryas octopetala L. heath in Finse, southwest Norway. In contrast to what we expected, we found that bryophyte abundance, species richness, and evenness increased over time in the control plots, indicating a positive response to ambient warming. However, the increase in bryophyte abundance and cover was suppressed in experimentally warmed plots compared with control plots. Bryophyte community composition changed in a similar direction in response to both ambient and experimental warming. Acrocarpous mosses were not affected stronger by warming than pleurocarpous mosses, but individual species and taxa showed contrasting responses. Our study highlights the importance of studying bryophyte responses to environmental change, as well as combining long-term observations with experimental warming.

Crushed rocks stabilized with organosilane and lignosulfonate in pavement unbound layers: Repeated load triaxial tests

The creation of the new “Ferry-Free Coastal Highway Route E39” in southwest Norway entails the production of a remarkable quantity of crushed rocks. These resources could be beneficially employed as aggregates in the unbound courses of the highway itself or other road pavements present nearby. Two innovative stabilizing agents, organosilane and lignosulfonate, can significantly enhance the key properties, namely, resilient modulus and resistance against permanent deformation, of the aggregates that are excessively weak in their natural state. The beneficial effect offered by the additives was thoroughly evaluated by performing repeated load triaxial tests. The study adopted the most common numerical models to describe these two key mechanical properties. The increase in the resilient modulus and reduction in the accumulated vertical permanent deformation show the beneficial impact of the additives. Furthermore, a finite element model was created to simulate the repeated load triaxial test by implementing nonlinear elastic and plastic constitutive relationships.

Modeling Nickel Leaching from Abandoned Mine Tailing Deposits in Jøssingfjorden

Underwater disposal of mine tailings in lakes and seas has been considered favorable due to the geochemical stability obtained during long-term storage in anoxic sediments. Sulfides are stable in the ore; however, oxidation and transformation of some substances into more soluble forms may impact bioavailability processes and enhance the risk of toxic effects in the aquatic environment. The goal of this work was to construct a model for simulating the nickel (Ni) cycle in the water column and upper sediments and apply it to the mine tailing sea deposit in the Jøssingfjord, SouthWest Norway. A one-dimensional (1D) benthic–pelagic coupled biogeochemical model, BROM, supplemented with a Ni module specifically developed for the study was used. The model was optimized using field data collected from the fjord. The model predicted that the current high Ni concentrations in the sediment can be a potential source of Ni leaching to the water column until about 2040. The top 10 cm of sediments were classified as being of “poor” environmental state according to the Norwegian Quality Standards. A numerical experiment predicted that with complete cessation of the discharges there would be an improvement in the environmental state of sediment to “good” in about 20 years. On the other hand, doubling of discharge would lead to an increase in the Ni content in the sediment, approaching the boundary of the “very poor” environmental state. The model results demonstrated that Ni leaching from the sea deposits may be increased due to sediment reworking by bioturbation at the sediment–water interface. The model can be an instrument for analysis of different scenarios for mine tailing activities from point of view of reduction of environmental impact as a component of the best available technology.

Early-Onset Sepsis in Neonates - A Population-Based Study in South-West Norway From 1996 to 2018.

Background: The epidemiology of early-onset sepsis (EOS) may change over time. Longitudinal surveillance of causative pathogens, antibiotic susceptibility patterns and antibiotic therapy is important for optimal therapy strategies.Objectives: To describe the incidence of culture-confirmed EOS, causative pathogens, antibiotic susceptibility patterns and antibiotic therapy over a 23-year period.Methods: Retrospective population-based study from a single-center neonatal intensive care unit at Stavanger University Hospital, Norway, covering a population in South-West Norway, during the 23-year period 1996–2018.Results: Of 104,377 live born infants, 101 infants (0.97/1,000) had culture-confirmed EOS; 89 with Gram positive and 12 with Gram-negative bacteria. The EOS-attributable mortality was 6/101 (5.8%). For the three most prevalent pathogens the incidences were; Group B streptococcus (GBS) 0.57/1,000, Escherichia coli 0.11/1,000 and viridans group streptococci (VGS) 0.10/1,000. GBS was the most common pathogen (59/93; 63%) in infants with gestational age (GA) ≥ 28 weeks. In contrast, among extremely preterm infants (GA <28 weeks) the incidence of E. coli infection was higher than for GBS infection. The second most common bacterial pathogens causing EOS among term infants were VGS. There was no change in the incidence of EOS for the entire study period, but from 2000 to 2018 there was a mean decline in EOS by 6% per year (95% CI 1%−10%) (p = 0.019). The incidences of GBS and E. coli did not change during the study period. The initial empirical antibiotic regimen for EOS was in all cases a combination of benzylpenicillin or ampicillin and an aminoglycoside, but in 21/101 (21%) of cases a broad-spectrum antibiotic was either added or substituted this regimen. In 2/101 (2%) EOS cases, the pathogens were nonsusceptible to the empirical antibiotic regimen. All E. coli isolates were susceptible to aminoglycosides.Conclusion: GBS was the most common causative pathogens in EOS, but E. coli dominated in infants with GA <28 weeks. There was no change in the incidence of EOS during the entire study period. The current empiric regimen with benzylpenicillin and gentamicin provides a very high coverage for EOS in our setting.

Karismatisk bergkrystall fra Ryfylkeheiane? Smykkestein som identitetsmarkør i yngre jernalder

In the 1960s and 1970s, large scale surveys related to hydro power developments in montane areas in Southwest Norway, recorded several rock crystals deposits and sites where crystals from these had been used both in the Stone Age and the Late Iron Age period. The Late Iron Age sites were interpreted as the first proof of locally produced rock crystal beads. In this article, I combine the production sites and rock crystal deposits to describe the operational chain of local bead production. This serves as the point of departure for a consideration of the value ascribed raw materials, local or regional vs. imported goods. I argue that symbolic aspects beyond economic value may have been the incentive for the local production, that is, qualities, such as rock crystals’ aesthetic, affective, or indeed charisma. Rock crystal beads from Late Iron Age graves in Rogaland are used as examples.

Hverken grav eller rydning – rituelle røyser fra yngre bronsealder–førromersk jernalder på Sømme i Rogaland

This article discusses cairns as ritual constructions during the Late Bronze and Pre-Roman Iron Ages in Southwest Norway. The basis for the discussion are two cairns from Sømme in Sola, Rogaland. It is suggested that the cairns are part of rituals related to settlement expansion and a rapid transformation of the landscape during the period.

Lake Sediments Reveal Large Variations in Flood Frequency Over the Last 6,500 Years in South-Western Norway

Lake sediments can retain imprints of past floods, enabling reconstructions that span well beyond instrumental time series. Time series covering thousands of years can document the natural range of flood variability, which is critical for understanding the potential causality between changing flood patterns and climate. Here, we analyzed sediments from Lake Sandvinvatnet in southwest Norway. Detailed environmental magnetic analyses of an 830cm-long sediment core covering the last 6,500 years captured decadal scale trends in local flood frequency. Magnetic susceptibility (MS) assessments were carried out both on split cores and individual samples to track variability in sedimentary influx; the ratios of MS measured at 77 K and 293 K (MS ratios) provided information on potential changes in source regions. The results suggested that sediments from the Buerdalen valley dominate the signal in the core, and the amount of ferromagnetic (high MS) carriers increases during flood events. These carriers were assumed to be transported from slope deposits in Buerdalen during rainstorm-triggered flood events. The reconstructed flood frequency, based on sediment layers with ferromagnetic carriers, showed high variability over the past 6,500 years, and the finding was validated by overlapping with known historical floods in the area. We observed periods with a high frequency of extreme floods (4100-3140 cal. yr BP) compared with intervals with a few or no extreme floods (6050-4100 cal. yr BP). Floods in this region are commonly a result of intense rain events during fall and snow and glacial melt during late spring and summer. The systematic frequency changes during the past 6,500 years suggest a certain persistency in the processes that cause floods, where mean trends in summer temperature and precipitation may have played a role.

"A cleaner break": Genetic divergence between geographic groups and sympatric phenotypes revealed in ballan wrasse (Labrus bergylta).

Capture and long‐distance translocation of cleaner fish to control lice infestations on marine salmonid farms has the potential to influence wild populations via overexploitation in source regions, and introgression in recipient regions. Knowledge of population genetic structure is therefore required. We studied the genetic structure of ballan wrasse, a phenotypically diverse and extensively used cleaner fish, from 18 locations in Norway and Sweden, and from Galicia, Spain, using 82 SNP markers. We detected two very distinct genetic groups in Scandinavia, northwestern and southeastern. These groups were split by a stretch of sandy beaches in southwest Norway, representing a habitat discontinuity for this rocky shore associated benthic egg‐laying species. Wrasse from Galicia were highly differentiated from all Scandinavian locations, but more similar to northwestern than southeastern locations. Distinct genetic differences were observed between sympatric spotty and plain phenotypes in Galicia, but not in Scandinavia. The mechanisms underlying the geographic patterns between phenotypes are discussed, but not identified. We conclude that extensive aquaculture‐mediated translocation of ballan wrasse from Sweden and southern Norway to western and middle Norway has the potential to mix genetically distinct populations. These results question the sustainability of the current cleaner fish practice.

Picking up the Pieces

This article centers on a discussion of blade fragments from two Late Mesolithic assemblages recovered during a recent excavation project in Rogaland, southwest Norway. Analysis undertaken during post excavation cataloging of lithic artefacts suggests some retouched and edge damaged pieces, represent minimally modified tools. The temporal context of the Sola finds offers an opportunity to reorientate research related to the northeast European/‘Post-Swiderian’ technological complex of which such tools were a central component. The studied fragments suggest that the two closely spaced areas may represent specialized, broadly contemporary activity. The results of this preliminary study highlight the latent interpretive potential of this relatively abundant yet somewhat intractable artefact class.

Constructing Identities

This book explores the construction of regional identities in the Early Bronze Age through the temporal variation in burial practice in Southwest Norway. Earthen barrows from the regions Etne, Karmøy, Jæren, and Lista are used as the archaeological source for this study. How historically constituted structures together with external practice form part of an open-ended process of identity construction is investigated. Previous research has often used a set, rigid definition of identity, and earthen barrows along the coast of Southwest Norway have therefore frequently been portrayed as part of a southern Scandinavian culture. These perceptions are not necessarily wrong, but neglect the complicated processes that give rise to groups. In this study it is argued that patterns found in the material remains, both unintentional and intentional, express regional variation. Through a quantitative methodology based on a selection of focus points and spatial analysis in ArcGIS the multifaceted process behind identity construction is showcased. As a result, the southwest coast of Norway during the Early Bronze Age can be seen as a more complex and dynamic region. Although many similarities between regions are shared, they are also clearly divided and competitive.

Notau – the Hanseatic harbour at Avaldsnes, south-west Norway: written sources, maps and place-names

Written sources, mostly of German origin from the fifteenth century, mention Notau, a Hanseatic harbour somewhere in the south-western part of Norway. Ships from towns, including Lübeck, Danzig and Kampen, called here. Dutch maps from the sixteenth and seventeenth centuries show that Notau was situated on the island of Karmøy in Rogaland county. The placename ‘Nottå’ has been used in modern times for locations at two islands belonging to the royal farm of Avaldsnes. Most probably one of these islands was called ‘Nautøy’ in the medieval period, becoming Notau in German. The written sources indicate that the Germans built houses in Notau, where the merchants are likely to have traded with the inhabitants of the region.

Maritime-archaeological investigations of the Hanseatic harbour at Avaldsnes

Investigations of the medieval harbour at the important royal manor of Avaldsnes, south-west Norway, revealed extensive underwater cultural layers and structures like ballast heaps and jetty foundations from the thirteenth until the early sixteenth century. The finds cover a large area and the conditions for preservation of the archaeological material is excellent. A waiting harbour at this strategic site along the fairway to Bergen probably got new functions and became the arena for intense activity during a 100-year period c. 1350–1450. The site known from written sources as Notau was most likely part of the same economic network as Bergen with ties to Hanseatic cities like Lübeck and Danzig. The pottery found on the sea bottom reveals an even wider range of international connections. The results have implications for the relationship between the Norwegian king and the Hanse and the Hanse’s activity outside of the medieval towns. The site is largely undisturbed by modern development and thus very well suited for future research.