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.
2016
Forfattere
Jyrki Jauhiainen Hanna Marika Silvennoinen Mari Könönen Suwido Limin Harri VasanderSammendrag
Extensive draining at tropical ombrotrophic peatlands in Southeast Asia has made these landscapes a global ‘hot spots’ for greenhouse gas emissions. Management practices and fires have changed substrate status, which affects microbial processes. Here, we present data on how change in management practices affect carbon (C) mineralization processes at these soils. We compared the C mineralization potentials of undrained swamp forest peat to those of abandoned peat (deforested, drained and burned peatlands in degraded condition) at various depths, with and without additional substrates (glucose, glutamate and nitrate), under oxic and anoxic conditions through ex situ experiments. Carbon mineralization (CO2 and CH4 production) rates were higher in the forest peat, with higher litter deposition and C availability. Production rates decreased with peat depth coinciding with decreasing availability of labile C. Consequently, the increase in production rates after labile substrate addition was relatively modest in forest peat as compared to the abandoned site and from the top layers as compared to deeper layers. Methanogenesis had little importance in total C loss. Adding labile C and nitrogen (N) enhanced heterotrophic CO2 production more than only addition of N. Surprisingly, oxygen availability did not limit CO2 production rates, but anoxic respiration also yielded substantial rates, especially at the forest peat. Flooding of these sites will therefore reduce, but not completely cease, peat C-loss. Reintroduced vegetation and fertilization in abandoned peatlands can enrich the peat with labile C and N compounds and thus lead to increased microbiological activity.
Forfattere
Anna Sandak Ingunn Burud Andreas Svarstad Flø Thomas Kringlebotn Thiis Lone Ross Jakub SandakSammendrag
Det er ikke registrert sammendrag
Forfattere
Sebastian Sippel Holger Lange Miguel D. Mahecha Michael Hauhs Paul Bodesheim Thomas W. Kaminski Fabian Gans Osvaldo A. RossoSammendrag
Det er ikke registrert sammendrag
Sammendrag
Measuring energy and matter fluxes between the atmosphere and vegetation using the Eddy Covariance (EC) technique is the state-of-the-art method to quantify carbon exchange between terrestrial ecosystems and their surrounding. The EC equipment is usually mounted onto a flux tower reaching higher than the local canopy. Today, more than 600 flux towers are in operation worldwide. The methodological requirements lead to high sampling frequency (20 Hz) and thus to the production of very long time series. These are related to temperature, wind components, water vapour, heat and gas exchange, and others. In this chapter, the potential of Recurrence Analysis (RA) to investigate the dynamics of this atmosphere-vegetation boundary system is elucidated. In particular, the effect of temporal resolution, the identification of periods particular suitable for reliable EC flux calculations, and the detection of transitions between dynamical regimes will be highlighted.
Forfattere
Ivar Mysterud Gry Koller Klaus Høiland Tor Carlsen Arild SlettenSammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Fungi within the Colletotrichum acutatum species complex occur asymptomatically on plant parts of many different plant species. Leaves from apple orchards in southern Norway were sampled, frozen for five hours and incubated for six days to reveal presence of asymptomatic infections of C. acutatum. Number of leaves (incidence) and leaf area covered (severity) with conidial masses of C. acutatum were assessed biweekly on cv. Aroma from late May to late September during three growing seasons. The first finding of conidial masses occurred in the second half of July, and there was a higher incidence occurring in August and September. Sampling of leaves from fruit spurs and vegetative shoots of cvs. Aroma and Elstar showed that conidial masses of C. acutatum developed on leaves on both shoot types, and there was no difference in incidence between these two types. The fungus was detected on leaves from six of eight commercial orchards of cv. Aroma over three years, with a mean incidence of 5.5 %. After storage, bitter rot was found on apple fruit from all eight orchards. There was no correlation between incidence of conidial masses of C. acutatum on leaves and on fruit. In all orchards and seasons investigated, incidence and severity on leaves varied from 0 to 67%and 0 to 85 %, respectively. The discovery of apple leaves containing conidial masses of C. acutatum clearly indicate for leaves as a potential source of inoculum for fruit infections.
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Einar Heegaard Lynne Boddy Jefferey M. Diez Rune Halvorsen Håvard Kauserud Thomas W. Kuyper Claus Bässler Ulf Büntgen Alan C. Gange Irmgard Krisai-Greilhuber Carrie Joy Andrew Francouis Ayer Klaus Høiland Paul M. Kirk Simon EgliSammendrag
Despite the critical importance of fungi as symbionts with plants, resources for animals, and drivers of ecosystem function, the spatiotemporal distributions of fungi remain poorly understood. The belowground life cycle of fungi makes it difficult to assess spatial patterns and dynamic processes even with recent molecular techniques. Here we offer an explicit spatiotemporal Bayesian inference of the drivers behind spatial distributions from investigation of a Swiss inventory of fungal fruit bodies. The unique inventory includes three temperate forest sites in which a total of 73 952 fungal fruit bodies were recorded systematically in a spatially explicit design between 1992 and 2006. Our motivation is to understand how broad-scale climate factors may influence spatiotemporal dynamics of fungal fruiting within forests, and if any such effects vary between two functional groups, ectomycorrhizal (ECM) and saprotrophic fungi. For both groups we asked: 1) how consistent are the locations of fruiting patches, the sizes of patches, the quantities of fruit bodies, and of prevalence (occupancy)? 2) Do the annual spatial characteristics of fungal fruiting change systematically over time? 3) Are spatial characteristics of fungal fruiting driven by climatic variation? We found high inter-annual continuity in fruiting for both functional groups. The saprotrophic species were characterised by small patches with variable fruit body counts. In contrast, ECM species were present in larger, but more distinctly delimited patches. The spatial characteristics of the fungal community were only indirectly influenced by climate. However, climate variability influenced overall yields and prevalence, which again links to spatial structure of fruit bodies. Both yield and prevalence were correlated with the amplitudes of occurrence and of fruit body counts, but only prevalence influenced the spatial range. Summarizing, climatic variability affects forest-stand fungal distributions via its influence on yield (amount) and prevalence (occupancy), whereas fungal life-history strategies dictate fine-scale spatial characteristics.
Forfattere
Carmen-Mihaela Popescu Callum Aidan Stephen Hill Craig KennedySammendrag
Understanding the hydration of the collagen historic parchments is of great importance to the conservation and restoration processes. In this study, modern and historic (dated 1817 and 1769) parchments were investigated using dynamic water vapour adsorption/desorption (sorption) experiments. The relationship between the equilibrium moisture content against the relative humidity at constant temperature for two consecutive sorption cycles, the hysteresis and kinetic properties were analysed for different parchments from a historic archive. It was found that historical parchment samples exhibited higher equilibrium moisture content levels throughout most of the hygroscopic range and the hysteresis was greater than that of the contemporary sample. The samples were all found to obey parallel exponential kinetics for both adsorption and desorption. By applying the parallel exponential kinetic model, it was observed that the difference in the hysteresis is apparently mostly due to changes in the collagen matrix relaxation processes.