Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2025
Abstract
No abstract has been registered
Authors
Gunhild Bødtker Claire Coutris Eva Marie-Louise Denison Åsa Frostegård Erik J. Joner Bjørn Tore Lunestad Elisabeth Henie Madslien Kaare Magne Nielsen Pål TrosvikAbstract
In this self-tasking scoping review, VKM will map research about the environmental impacts of biodegradable plastics, including biodegradation rates and material persistence in different environments and geographical regions, the influence on microbial ecology and activity, and ecotoxicological effects of materials and associated chemical substances. Related to this is also research associated with the development of methodology, standards, environmental risk assessment, life cycle impact analyses, material sources and properties of biodegradable plastics and products. The aim is to 1) determine the extent of evidence summarised in reviews and original research papers within this emerging research area and 2) map the evidence according to the materials and chemicals studied, types of environments and geographical regions covered, the hypotheses addressed, the type of endpoints assessed and the reported key findings. Systematic literature searches will be performed to identify the summarised evidence, applying APRIO to develop a tailored search protocol that addresses the multi- and cross-disciplinary nature of the research area. We will select and map the identified publications applying Rayyan and sort them into three categories based on their main scientific focus and aim of study: 1) material properties and application, 2) biodegradation and microbial ecology, and 3) ecotoxicology. There will be no geographical restrictions on the search and study selection, but in the data charting process we will highlight findings relevant to Norway and other Nordic countries. The current project adheres to the “Preferred Reporting Items for Systematic Reviews and MetaAnalyses extension for Scoping Reviews (PRISMA-ScR) Checklist” for protocol development and reporting. We will address uncertainties associated with research studies applying EFSA guidelines and their generic list of common types of uncertainty affecting scientific studies and assessments.
Authors
Heikki Korpunen Yrjö Nuutinen Paula Jylhä Lars Eliasson Aksel Granhus Juha Laitila Stephan Hoffmann Timo MuhonenAbstract
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Authors
Ararsa Derese Seboka Lu Feng John Morken Muyiwa S. Adaramola Getachew Birhanu Abera Gebresilassie Asnake EwunieAbstract
No abstract has been registered
Authors
Adrian Unc Majdi R. Abou Najm Paul Eric Aspholm Tirupati Bolisetti Colleen Charles Ranjan Datta Trine Eggen Belinda Eline Flem Getu Hailu Eldbjørg Sofie Heimstad Margot Hurlbert Meriam Karlsson Marius Støylen Korsnes Arthur Nash David Parsons Radha Sivarajan Sajeevan Narasinha J. Shurpali Govert Valkenburg Danielle Wilde Bing Wu Sandra F. Yanni Debasmita MisraAbstract
No abstract has been registered
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No abstract has been registered
Abstract
Small, forested catchments are prototypes of terrestrial ecosystems and have been studied in several disciplines of environmental science over several decades. Time series of water and matter fluxes and nutrient concentrations from these systems exhibit a bewildering diversity of spatiotemporal patterns, indicating the intricate nature of processes acting on a large range of time scales. Nonlinear dynamics is an obvious framework to investigate catchment time series. We analyzed selected long-term data from three headwater catchments in the Bramke valley, Harz mountains, Lower Saxony in Germany at common biweekly resolution for the period 1991 to 2023. For every time series, we performed gap filling, detrending, and removal of the annual cycle using singular system analysis (SSA), and then calculated metrics based on ordinal pattern statistics: the permutation entropy, permutation complexity, and Fisher information, as well as their generalized versions (q-entropy and α-entropy). Further, the position of each variable in Tarnopolski diagrams is displayed and compared to reference stochastic processes, like fractional Brownian motion, fractional Gaussian noise, and β noise. Still another way of distinguishing deterministic chaos and structured noise, and quantifying the latter, is provided by the complexity from ordinal pattern positioned slopes (COPPS). We also constructed horizontal visibility graphs and estimated the exponent of the decay of the degree distribution. Taken together, the analyses create a characterization of the dynamics of these systems which can be scrutinized for universality, either across variables or between the three geographically very close catchments.
Abstract
Climatic drought and changes in precipitation patterns are key features of the ongoing and predicted climatic changes in northern latitudes such as the boreal forest of Norway. Recent droughts highlight on the possible difficult future of spruce forests in southern Norway. To better understand and monitor these forests under a more extreme climate, it is crucial to gain a better understanding of the water relations of spruce trees across forest stands. Sap flow sensors are typically used for directly measuring the water demands for transpiration in individual trees. There are however limitations to their use in examining the hydraulic and physiological responses to extreme water supply variability: i) manufactured high-resolution sensors such as those following the Heat Ratio Method (HRM) or Heat Field Deformation (HFD) are expensive, limiting their deployment to a few trees in a stand, and ii) the sap flow sensors only measure the movement of water within the active sapwood, not accessing other physiological mechanisms and responses (radial growth, water storage) associated with stress response. Point dendrometers have become increasingly used, monitoring sub-daily stem size fluctuations resulting from both seasonal patterns of radial growth increment and the dynamics of plant tissue water balance. Manufactured point dendrometers are much cheaper to buy and easier to install and maintain than manufactured sap flow sensors. They can therefore be much more extensively deployed across forest stands. We aimed to analyse the relationship between sub-daily stem diameter changes and sap flow using point dendrometers and HRM sap flow sensors installed in a Norway spruce forest located 50 km north of Oslo, Norway. We linked these relationships with individual tree physical attributes, meteorology and soil climate over two growing seasons in 2022 and 2023. Our goal was to assess whether a predictive model of sap flow could be built from measured diameter changes, tree properties and climate, to ultimately reduce the uncertainty of stand level transpiration estimation at the daily resolution across entire forest stands.
Authors
Klaus Steenberg Larsen Carl-Fredrik Johannesson Jenni Nordén Holger Lange Hanna Marika SilvennoinenAbstract
Non-steady-state chambers are widely used for measuring the exchange of greenhouse gases (GHGs) between soils or ecosystems and the atmosphere. It is known that non-steady-state chambers induce a non-linear concentration development inside the chamber after closure, even across short chamber closure periods, and that both linear and non-linear flux estimates are impacted by the chamber closure period itself. However, despite the existence of recommendations on how long to keep the chamber closed, it has been little explored to what extent the length of the chamber closure period affects the estimated flux rates, and which closure periods may provide the most accurate linear and non-linear flux estimates. In the current study, we analyzed how linear regression and Hutchinson and Mosier (1981) modeled flux estimates were affected by the length of the chamber closure period by increasing it in increments of 30 s, with a minimum and maximum chamber closure period of 60 and 300 s, respectively. Across 3,159 individual soil CO2 and CH4 flux measurements, the effect of chamber closure period length varied between 1.4–8.0% for linear regression estimates and between 0.4–17.8% for Hutchinson–Mosier estimates and the largest effect sizes were observed when the measured fluxes were high. Both linear regression and Hutchinson–Mosier based flux estimates decreased as the chamber closure period increased. This effect has been observed previously when using linear regression models, but the observed effect on Hutchinson-Mosier modeled estimates is a novel finding. We observed a clear convergence between the short-period linear regression estimates and the long-period Hutchinson–Mosier estimates, showing that closure periods as short as possible should be used for linear regression flux estimation, while ensuring long-enough closure periods to observe a stabilization of flux estimates over time when using the Hutchinson-Mosier model. Our analysis was based on soil flux measurements, but because the perturbation of the concentration gradient is related to the non-steady-state chamber technique rather than the measured ecosystem component, our results have implications for all flux measurements conducted with non-steady-state chambers. However, optimal chamber closure times may depend on individual chamber designs and analyzer setups, which suggests testing individual chamber/system designs for optimal measurement periods prior to field application