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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.

2023

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Abstract

The anaerobic digestion (AD) of food waste (FW) was easy to acidify and accumulate ammonia nitrogen. Adding exogenous materials to the AD system can enhance its conversion efficiency by alleviating acidification and ammonia nitrogen inhibition. This work investigated the effects of the addition frequency and additive amount on the AD of FW with increasing organic loading rate (OLR). When the OLR was 3.0 g VS per L per day and the concentration of the additives was 0.5 g per L per day, the stable methane yield reached 263 ± 22 mL per g VS, which was higher than that of the group without the additives (189 mL per g VS). Methanosaetaceae was the dominant archaea, with a maximum abundance of 93.25%. Through machine learning analysis, it was found that the optimal daily methane yield could be achieved. When the OLR was within the range of 0–3.0 g VS per L per day, the pH was within the range of 7.6–8.0, and the additive concentration was more than 0.5 g per L per day. This study proposed a novel additive and determined its usage strategy for regulating the AD of FW through experimental and simulation approaches.

Abstract

This report presents results of two plum cultivars and selections trials, performed during 2013-2021 and 2016-2021 at Ullensvang. In total, 19 plum cultivars were evaluated: 4 from the Institute of Horticulture, Čačak, Serbia; 9 cultivars and selections bred by Einar Ruud, Søgne; 3 plum selections from Graminor, Njøs and 1 cultivar from NMBU. Cultivars Opal and Čačanska lepotica served as control. The aim of these reported plum cultivar trials was to investigate recently released plum cultivars and premium selections from Norwegian and Serbian breeding programs from pomological, agronomical, and biochemical point of view, identify the most important quality parameters, and select cultivars with desirable traits for the modern market in Norway. Based on overall fruit quality and tree productivity, selections NPr. 458 and Anne (R21) (Rudiplomme, if a DNA-test reveal that it is the same as the cultivar Anne (R 21)) are selected for fresh consumption and can be recommended for further commercial growing tests. Due to very sweet and good fruit taste, cultivars Boranka and Ellen might be used for jam.

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Abstract

Arctic ecosystems are increasingly exposed to extreme climatic events throughout the year, which can affect species performance. Cryptogams (bryophytes and lichens) provide important ecosystem services in polar ecosystems but may be physiologically affected or killed by extreme events. Through field and laboratory manipulations, we compared physiological responses of seven dominant sub-Arctic cryptogams (three bryophytes, four lichens) to single events and factorial combinations of mid-winter heatwave (6°C for 7 days), re-freezing, snow removal and summer nitrogen addition. We aimed to identify which mosses and lichens are vulnerable to these abiotic extremes and if combinations would exacerbate physiological responses. Combinations of extremes resulted in stronger species responses but included idiosyncratic species-specific responses. Species that remained dormant during winter (March), irrespective of extremes, showed little physiological response during summer (August). However, winter physiological activity, and response to winter extremes, was not consistently associated with summer physiological impacts. Winter extremes affect cryptogam physiology, but summer responses appear mild, and lichens affect the photobiont more than the mycobiont. Accounting for Arctic cryptogam response to multiple climatic extremes in ecosystem functioning and modelling will require a better understanding of their winter eco-physiology and repair capabilities.

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Abstract

Wood decomposing fungi differ in their substrate affinities, but to what extent factors like wood properties influence host specialization, compared to climate, is largely unknown. In this study, we analysed British field observations of 61 common wood decay species associated with 41 tree and shrub genera. While white rot fungi ranged from low-to high-substrate affinity, brown rot fungi were exclusively mid-to high-affinity. White rot fungi associated with dead fallen wood demonstrated the least substrate affinity. The composition of wood decomposer fungi was mostly structured by substrate properties, sorted between angiosperms and conifers. Any relationships with temporal and regional climate variability were of far less significance, but did predict community-based and substrate-usage host shifts, especially for fungi on fallen deadwood. Our results demonstrate that substrate shifts by wood-decay fungi will depend primarily upon their degree of affinity to, and the distribution of, related woody genera, followed less at regional levels by climate impacts.

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Abstract

The European spruce bark beetle Ips typographus and the North American spruce beetle Dendroctonus rufipennis cause high mortality of spruces on their native continents. Both species have been inadvertently transported beyond their native ranges. With similar climates and the presence of congeneric spruce hosts in Europe and North America, there is a risk that one or both bark beetle species become established into the non-native continent. There are many challenges that an introduced population of bark beetles would face, but an important prerequisite for establishment is the presence of suitable host trees. We tested the suitability of non-native versus native hosts by exposing cut bolts of Norway spruce (Picea abies), black spruce (Picea mariana) and white spruce (Picea glauca) to beetle attacks in the field in Norway and Canada. We quantified attack density, brood density and reproductive success of I. typographus and D. rufipennis in the three host species. We found that I. typographus attacked white and black spruce at comparable densities to its native host, Norway spruce, and with similar reproductive success in all three host species. In contrast, D. rufipennis strongly preferred to attack white spruce (a native host) but performed better in the novel Norway spruce host than it did in black spruce, a suboptimal native host. Our results suggest that I. typographus will find abundant and highly suitable hosts in North America, while D. rufipennis in Europe may experience reduced reproductive success in Norway spruce.

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Abstract

The anaerobic digestion of organic materials produces biogas; however, optimizing methane (CH4) content within biogas plants by capturing carbon dioxide (CO2) is one of the challenges for sustainable biomethane production. CH4 is separated from biogas, which is called biogas upgrading for biomethane production. In this regard, in-situ CO2 capture and utilization could be an alternative approach that can be achieved using conductive particles, where the conductive particles support the direct intraspecific electron transfer (DIET) to promote CH4 production. In this investigation, a carbon nanotube (CNT) was grown over conductive activated carbon (AC). Then an iron (Fe) nanoparticle was anchored (AC/CNT/Fe), which ultimately supported microbes to build the biofilm matrix, thereby enhancing the DIET for CH4 formation. The biogas production and CH4 content increased by 17.57 % and 15.91 %, respectively, when AC/CNT/Fe was utilized. Additionally, 18S rRNA gene sequencing reveals that Methanosarcinaceae and Methanobacteriaceae families were the most dominant microbes in the reactor when conductive particles (AC/CNT/Fe) were applied. The proposed study supports the stable operation of biogas plants to utilize CO2 for CH4 production by using surface-modified material.

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Abstract

Soil loss by erosion threatens food security and reduces the environmental quality of water bodies. Prolonged and extreme rainfalls are recognized as main drivers of soil erosion, and climate change predictions for large parts of the world foresee such increases in precipitation. Erosion rates are additionally affected by land use, which may change as a result of the shift from a fossil fuel-based economy to an economy relying on using renewable biomass, a “Bioeconomy”. In this study we aimed at investigating, through modelling, i) if future changes in land use, due to a bioeconomy, would increase the risk for soil loss and enhance suspended sediment yields in streams and ii) if these changes, when combined with climate change effects, would further aggravate suspended sediment conditions in a catchment. We used hydrological and bias adjusted climate models to compare the effect of seven land use pathways on discharge and sediment transport relative to a baseline scenario under present and future climate conditions. The study was carried out based on data from a small headwater stream, representative for cereal production areas of S-E Norway. By modelling our scenarios with the PERSiST and INCA-P models, we found that land use change had a greater influence on both future water discharge and sediment losses than a future climate. Changes from climate showed strongest differences on a seasonal basis. Out of the modelled land use pathways, a sustainable pathway manifested the least occurrence of extreme flood and sediment loss events under future climate; whereas a pathway geared towards self-sufficiency indicated the highest occurrence of such extreme events. Our findings show that careful attention must be placed on the land use and soil management in the region. To maintain freshwater quality, it will be increasingly important to implement environmental mitigation measures.