Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2018
Forfattere
Svein Solberg Johannes May Wiley Steven Bogren Johannes Breidenbach Torfinn Torp Belachew Gizachew ZelekeSammendrag
Monitoring changes in forest height, biomass and carbon stock is important for understanding the drivers of forest change, clarifying the geography and magnitude of the fluxes of the global carbon budget and for providing input data to REDD+. The objective of this study was to investigate the feasibility of covering these monitoring needs using InSAR DEM changes over time and associated estimates of forest biomass change and corresponding net CO2 emissions. A wall-to-wall map of net forest change for Uganda with its tropical forests was derived from two Digital Elevation Model (DEM) datasets, namely the SRTM acquired in 2000 and TanDEM-X acquired around 2012 based on Interferometric SAR (InSAR) and based on the height of the phase center. Errors in the form of bias, as well as parallel lines and belts having a certain height shift in the SRTM DEM were removed, and the penetration difference between X- and C-band SAR into the forest canopy was corrected. On average, we estimated X-band InSAR height to decrease by 7 cm during the period 2000–2012, corresponding to an estimated annual CO2 emission of 5 Mt for the entirety of Uganda. The uncertainty of this estimate given as a 95% confidence interval was 2.9–7.1 Mt. The presented method has a number of issues that require further research, including the particular SRTM biases and artifact errors; the penetration difference between the X- and C-band; the final height adjustment; and the validity of a linear conversion from InSAR height change to AGB change. However, the results corresponded well to other datasets on forest change and AGB stocks, concerning both their geographical variation and their aggregated values.
Forfattere
Olav Aaseth Hegnar Dejan Petrovic Bastien Bissaro Gry Alfredsen Aniko Varnai Vincent EijsinkSammendrag
Lytic polysaccharide monooxygenases (LPMOs) are copper-dependent enzymes that perform oxidative cleavage of recalcitrant polysaccharides. We have purified and characterized a recombinant family AA9 LPMO, LPMO9B, from Gloeophyllum trabeum (GtLPMO9B) which is active on both cellulose and xyloglucan. Activity of the enzyme was tested in the presence of three different reductants: ascorbic acid, gallic acid, and 2,3-dihydroxybenzoic acid (2,3-DHBA). Under standard aerobic conditions typically used in LPMO experiments, the first two reductants could drive LPMO catalysis whereas 2,3-DHBA could not. In agreement with the recent discovery that H2O2 can drive LPMO catalysis, we show that gradual addition of H2O2 allowed LPMO activity at very low, substoichiometric (relative to products formed) reductant concentrations. Most importantly, we found that while 2,3-DHBA is not capable of driving the LPMO reaction under standard aerobic conditions, it can do so in the presence of externally added H2O2. At alkaline pH, 2,3-DHBA is able to drive the LPMO reaction without externally added H2O2, and this ability overlaps entirely the endogenous generation of H2O2 by GtLPMO9B-catalyzed oxidation of 2,3-DHBA. These findings support the notion that H2O2 is a cosubstrate of LPMOs and provide insight into how LPMO reactions depend on, and may be controlled by, the choice of pH and reductant.
Sammendrag
WOOL QUALITY OF NORWEGIAN WHITE SPÆL SHEEP BREED Lise GRØVA 1), Inger Anne Boman 2) 1) NIBIO, Norwegian Institute of Bioeconomy Research, Gunnars veg 6, 6630 Tingvoll, Norway; lise.grova@nibio.no 2) NSG, Norwegian sheep and goat association, Postboks 104, N-1431 Ås The Norwegian White Speal Sheep are characterised by their fluke-shaped and tapered short tail, dual-coated wool and the ability to thrive under harsh environmental conditions. The income in Norwegian sheep farming comes from lamb meat, wool and pelts. Today, wool is of minor economic importance, commonly accounting for less than 10% of the income. However, the interest of wool as a sustainable and local fibre is increasing. Wool quality traits of the Norwegian White spæl breed has been reported to be declining; i.e. an increase in medulated fibres and in kemp. To address this challenge, there has been developed and incorporated 1) wool quality assessment tutorials for farmers and breeders, 2) included heritability estimates of wool fleece weight and quality class in index calculations, and 3) conducted OFDA analysis of wool from breeding rams for three consecutive years. The work was initiated by the research-project KRUS - Enhancing local wool value chains in Norway (NFR 244618/E50) and has been carried out by NIBIO, the Norwegian Sheep Breeders Association (NSG), Animalia and Norilia. Wool quality assessment tutorials for farmers and breeders are available as a.pdf and video for free download from NSG webpage (nsg.no). A ‘wool evaluation kit’ with a magnifier is available for purchase, also from NSG. Implementing index estimates was made possible when including fleece weigh and fleece classification from all sheared lambs at slaughter into the Norwegain National Sheep Recording system. Further, OFDA analysis were conducted on wool from breeding rams collected autumn 2015, 2016 and 2017. The wool samples were analysed using the optical FD analyser (OFDA100; BSC Electronics Pty Ltd, Western Australia, Australia). OFDA analysis is conducted to describe wool quality traits, development of quality traits over time and also development of quality traits at different age of breeding rams. Preliminary results from this study will be presented at the conference. Keywords: sheep, wool quality, Norwegian white spæl, dual felt, double-coat
Sammendrag
I denne rapporten redegjør vi for et forslag til kriteriebasert fastsetting av naturverdi for skog-områder som vurderes for vern. Målsettingen er å komme fram til et system som er operativt og mest mulig objektivt, der kriteriene er spesifisert ved variabler i naturtype- og beskrivelses-systemet Natur i Norge (NiN). Vi foreslår 12 kriterier knyttet til henholdsvis naturgitt mangfold (variasjon i naturtyper, landformer, treslag), naturskogsnærhet (død ved mengde og variasjon, gamle/store trær, trær med spesielt livsmedium) og områdets skogareal (størrelse). Vi har foreløpig ikke funnet å kunne anbefale et kriterium for faktiske eller potensielle artsforekomster, siden dette krever ytterligere utviklingsarbeid for å sikre tilstrekkelig objektiv bruk av et slikt kriterium. Også NiNs variabler for skogbestandsdynamikk, spesielt for naturskog, trenger mer utviklingsarbeid før disse kan brukes som kriterier for naturverdi i skogvernarbeidet. I tillegg til kriterier for naturverdi forslår vi også at svak arrondering av området og ev. påvirkning fra nye-re hogster, teknisk infrastruktur eller fremmede arter skal kunne gi et fratrekk i samlet verdi. Systemet angir både en verdirangering for de enkelte kriteriene og en sammenstilling av disse til en samlet verdiangivelse for området. For de enkelte kriteriene viderefører vi den firedelte verdiskalaen (0-3) som er brukt tidligere i skogvernarbeidet. For hvert trinn på denne skalaen spesifiseres en grenseverdi for hvert kriterium. Der det finnes et egnet datagrunnlag for kriteriene, foreslår vi at disse grenseverdiene legges til prosentilene 50, 80 og 95 i fordelingen av mulige kriterieverdier i norsk skog. Alternativt bør man skjønnsmessig tilstrebe en tilsvarende prioritering av forholdsvis høye grenseverdier for å skille ut de beste områdene fra de mer ordinære. For samlet verdi for område basert på kvantitativ bruk av kriteriene, foreslår vi også en firedelt skala (0-3), men her åpner vi for at en mer subjektiv tilleggsvurdering kan gi ett trinn høyere verdi for områder av særlig høy nasjonal eller internasjonal naturverdi. Vi foreslår at samlet verdi beregnes som et veid gjennomsnitt av verdiskårene for de enkelte kriteriene, først som samlet verdi for kriteriene for henholdsvis naturgitt mangfold og naturskogsnærhet, der-nest ved et veid gjennomsnitt av verdiene for naturgitt mangfold, naturskogsnærhet og størrelse. Denne samlete verdien er skalert til verdier mellom 0 og 3. Deretter vurderes om områdets arrondering eller ulike negative påvirkninger bør tilsi et fratrekk i verdien på inntil 1 verdienhet. Systemet er laget for å angi samlet naturverdi for enkeltområder, basert på kriterier med felles verditrinn for hele landet. Det innebærer at ev. regionale forskjeller i forutsetninger for å til-fredsstille de ulike kriteriene, ikke er tatt hensyn til. Vi anser at vurdering ev. gitte skogområder i en regional sammenheng er en oppgave for forvaltningen. Det er behov for nærmere vurdering av hvordan samlet verdi for et område avhenger av grenseverdiene for de ulike kriteriene og av vektene som ev. både kan differensieres mellom enkeltkriterier og mellom hovedgrupper av kriterier (naturgitt mangfold, naturskogsnærhet, størrelse). Dessuten bør systemet testes mot allerede vurderte områder for å se hvordan grense-verdier og vekter bør fastlegges for å få resultater som er tilstrekkelig konsistente med tidligere vurderinger. NØKKELORD : naturverdi, kriterier, skog, skogvern, Norge KEY WORDS : conservation value, criteria, forest, forest protection, Norway
Forfattere
Anastasia Georgantzopoulou Christian Vogelsang Claire Coutris Fabio Polesel Benedek Plosz Kuria Ndungu Patricia Almeida Carvalho Ailbhe MackenSammendrag
The increase in production and use of Ag and TiO2 nanomaterials has led to their release in wastewater streams and subsequently in the environment. Nanoparticles (NPs) can undergo transformations in environmental media such as wastewaters leading to an alteration in behavior, bioavailability and toxicity that may differ from their pristine counterparts and make predictions challenging. In this context, the overall goal of the study was to elucidate (i) the behavior and transformation of Ag and TiO2 NPs in realistic matrices such as wastewater effluents and activated sludge and (ii) the subsequent effects of transformed particles in comparison to their pristine counterparts. In this study, a laboratory-scale wastewater treatment system was established and combined with a battery of ecotoxicological assays and characterization techniques. The system contained activated sludge and was operated as a pre-denitrification system fed with synthetic wastewater spiked daily with 10 µg Ag NPs/L (PVP coated, 25 nm, nanoComposix) and 100 µg TiO2 NPs/L (nominal primary size of 5 nm, NM-101, JRC) over a period of 5 weeks. During that period the effluents were collected weekly and the excess sludge was stored for the evaluation of terrestrial toxicity. Samples from all reactors and effluents were collected weekly and analyzed by sequential filtration and ICP-MS to determine the partitioning of NPs and their transformation products. Transmission electron microscopy and sp-ICP-MS were performed on selected samples. The effects of aged particles were assessed using a battery of bioassays including freshwater and marine algae (growth inhibition and reactive oxygen species -ROS- formation), crustaceans, as well as in vitro models of relevance for NP toxicity assessement (RTgill-W1 cell line, effects on metabolic activity, epithelial integrity, ROS formation, gene expression). The extent of the observed effects was dependent on the organism exposed, with bottom feeding organisms and algae being more sensitive, while the in vitro model was a good tool for environmental samples. Furthermore, the biosolids generated from the lab-scale continuous system were used in terrestrial microcosm experiments, giving insight into the fate and potential accumulation in a model terrestrial system. Experimental data generated from the continuous-flow operation of the activated sludge system and the targeted batch experiments will be used to model the fate and the removal of NPs.
Forfattere
Jannis von Buttlar Jakob Zscheischler Anja Rammig Sebastian Sippel Markus Reichstein Alexander Knohl Martin Jung Olaf Menzer M. Altaf Arain Nina Buchmann Alessandro Cescatti Damiano Gianelle Gerard Kiely Beverly E. Law Vincenzo Magliulo Hank Margolis Harry McCaughey Lutz Merbold Mirco Migliavacca Leonardo Montagnani Walter Oechel Marian Pavelka Matthias Peichl Serge Rambal Antonio Raschi Russell L. Scott Francesco P. Vaccari Eva van Gorsel Andrej Varlagin Georg Wohlfahrt Miguel D. MahechaSammendrag
Extreme climatic events, such as droughts and heat stress, induce anomalies in ecosystem–atmosphere CO2 fluxes, such as gross primary production (GPP) and ecosystem respiration (Reco), and, hence, can change the net ecosystem carbon balance. However, despite our increasing understanding of the underlying mechanisms, the magnitudes of the impacts of different types of extremes on GPP and Reco within and between ecosystems remain poorly predicted. Here we aim to identify the major factors controlling the amplitude of extreme-event impacts on GPP, Reco, and the resulting net ecosystem production (NEP). We focus on the impacts of heat and drought and their combination. We identified hydrometeorological extreme events in consistently downscaled water availability and temperature measurements over a 30-year time period. We then used FLUXNET eddy covariance flux measurements to estimate the CO2 flux anomalies during these extreme events across dominant vegetation types and climate zones. Overall, our results indicate that short-term heat extremes increased respiration more strongly than they downregulated GPP, resulting in a moderate reduction in the ecosystem's carbon sink potential. In the absence of heat stress, droughts tended to have smaller and similarly dampening effects on both GPP and Reco and, hence, often resulted in neutral NEP responses. The combination of drought and heat typically led to a strong decrease in GPP, whereas heat and drought impacts on respiration partially offset each other. Taken together, compound heat and drought events led to the strongest C sink reduction compared to any single-factor extreme. A key insight of this paper, however, is that duration matters most: for heat stress during droughts, the magnitude of impacts systematically increased with duration, whereas under heat stress without drought, the response of Reco over time turned from an initial increase to a downregulation after about 2 weeks. This confirms earlier theories that not only the magnitude but also the duration of an extreme event determines its impact. Our study corroborates the results of several local site-level case studies but as a novelty generalizes these findings on the global scale. Specifically, we find that the different response functions of the two antipodal land–atmosphere fluxes GPP and Reco can also result in increasing NEP during certain extreme conditions. Apparently counterintuitive findings of this kind bear great potential for scrutinizing the mechanisms implemented in state-of-the-art terrestrial biosphere models and provide a benchmark for future model development and testing.
Forfattere
Zelalem Bekeko Chemeda Fininsa Shimelis Hussien Temam Hussien Dagne Wegari Belachew Asalf TadesseSammendrag
Fourteen advanced maize inbred lines and locally adapted hybrid maize (BH-540) as a check were used to investigate their reaction to GLS disease. Field experiments were conducted at Bako National Maize Research Centre in 2015 and 2016 main plan ng seasons arranged in a randomized complete block design (RCBD) with three replications. Artificial inoculation with Cercospora zeae-maydis was conducted by applying dry, ground, infected maize leaves into the whorls of younger maize plants. Data on agronomic and disease parameters (latent period, disease severity, disease incidence and lesion type) were recorded from the middle two rows. From the combined analysis of variance, maize genotypes showed significant differences with reaction to GLS indicating the existence of genetic variability among the selected genotypes. Highly significant differences were also observed among entries for all agronomic parameters in both seasons. Gray leaf spot incidence and severity varied among genotypes and between years. The mean GLS incidence and severity were higher in 2016 than 2015. GLS disease incidence in two years ranged from 35% on Sc22 to 95% on CML-387 and severity ranged from 15% on A-7016 to 75% on CKL05003. Significant differences in epidemic variability were also observed among genotypes and seasons. From the analysis of disease progress curves Logistic model (R2=94.55) better described the disease progress curves than the Gompertz model (R2=91.50). Parents; P6 and P8 had the most desirable quality for the most of agronomic traits whereas P2, P7 and P9 were the best parents for grain yield. Among all inbred lines, P6, P7 and P14 were iden fied as the most desirable sources of genes for GLS disease resistance. But P6, P7, P8 and P14 were iden fied as the best genotypes in yield, yield related traits and GLS disease parameters. Thus, these parents were recommended to be used in breeding programs with a purpose of developing high yielder and GLS disease resistant open pollinated varieties. In conclusion this study identified potential and promising high yielding and GLS resistant open pollinated genotypes (CKL05017-B-B, CML-395, CML-387, A-7016, Gu o and Sc22). Therefore, it is recommended that these OPVs can be used by resource poor farmers for direct production where this disease is the most prevalent and/or for further breeding programs in generating novel hybrids for future use.
Forfattere
James Johnson Elisabeth Graf Pannatier Stefano Carnicelli Guia Cecchini Nicholas Clarke Nathalie Cools Karin Hansen Henning Meesenburg Tiina M. Nieminen Gunilla Pihl-Karlsson Hugues Titeux Elena Vanguelova Arne Verstraeten Lars Vesterdal Peter Waldner Mathieu JonardSammendrag
Acid deposition arising from sulphur (S) and nitrogen (N) emissions from fossil fuel combustion and agriculture has contributed to the acidification of terrestrial ecosys- tems in many regions globally. However, in Europe and North America, S deposition has greatly decreased in recent decades due to emissions controls. In this study, we assessed the response of soil solution chemistry in mineral horizons of European forests to these changes. Trends in pH, acid neutralizing capacity (ANC), major ions, total aluminium (Al tot ) and dissolved organic carbon were determined for the period 1995–2012. Plots with at least 10 years of observations from the ICP Forests moni- toring network were used. Trends were assessed for the upper mineral soil (10– 20 cm, 104 plots) and subsoil (40–80 cm, 162 plots). There was a large decrease in the concentration of sulphate (SO 2 4 ) in soil solution; over a 10-year period (2000– 2010), SO 2 4 decreased by 52% at 10–20 cm and 40% at 40–80 cm. Nitrate was unchanged at 10–20 cm but decreased at 40–80 cm. The decrease in acid anions was accompanied by a large and significant decrease in the concentration of the nutrient base cations: calcium, magnesium and potassium (Bc = Ca 2+ + Mg 2+ + K + ) and Al tot over the entire dataset. The response of soil solution acidity was nonuni- form. At 10–20 cm, ANC increased in acid-sensitive soils (base saturation ≤10%) indicating a recovery, but ANC decreased in soils with base saturation >10%. At 40–80 cm, ANC remained unchanged in acid-sensitive soils (base saturation ≤20%, pH CaCl 2 ≤ 4.5) and decreased in better-buffered soils (base saturation >20%, pH CaCl 2 > 4.5). In addition, the molar ratio of Bc to Al tot either did not change or decreased. The results suggest a long-time lag between emission abatement and changes in soil solution acidity and underline the importance of long-term monitor- ing in evaluating ecosystem response to decreases in deposition.
Sammendrag
Remote sensing observations provide important information about vegetation and carbon dynamics on large scales, flux towers in situ measurements at the plot scale. Events important for ecological processes, such as hydrometeorological extremes, often happen at spatiotemporal scales between those covered by these two data sources. We discuss the event detection rates of ecological in situ networks as a function of their size and design. Using extreme reductions of the Fraction of Absorbed Photosynthetically Active Radiation (FAPAR), available from satellite missions, as a proxy for substantial losses in Gross Primary Productivity (GPP), we rank historical events according to their severity, and show how many would have been detected with a given number of randomly placed sites, discuss the problem of clustering of sites, and compare the theoretical results with the existing networks FLUXNET and NEON. The further spatio-temporal expansion of the ICOS network should carefully consider the size distribution of extreme events in order to be able to monitor their impacts on the terrestrial biosphere.
Sammendrag
Different seed lots of Pinus spp. cultivated within South Africa were screened for the presence or absence of seed-borne fungi according to modified ISTA (International Seed Testing Association) prescribed protocols. Numerous (454 isolates) fungi were successfully isolated, purified and stored using agar slants and cryopreservation. Sydowia polyspora was isolated from six different seed lots from three Pinus species (P. greggii (South), P. elliottii and P. taeda) and was morphologically and molecularly identified. Koch’s postulates was fulfilled by inoculating one year old seedlings (wounded and unwounded) with a spore suspension (107 ml-1) obtained from 30 day old pure cultures grown on PDA. Inoculated and uninoculated control seedlings were incubated in a greenhouse at 220C until symptom development. Sydowia polyspora was re-isolated from symptomatic needles with both wounded and unwounded needles showing characteristic symptoms. No symptoms were apparent on the control seedlings. To the best of our knowledge, this is the first report of the fungus being isolated and recorded within the country. Further investigations will look at the prevalence, pathogenicity and characterization of the fungus within South Africa.