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Biogenic NMVOCs are mainly formed by plants and microorganisms. They have strong impact on the local atmospheric chemistry when emitted to the atmosphere. The objective of this study was to determine if there are significant emissions of non-methane volatile organic compounds (NMVOCs) from a subarctic mire in northern Sweden. Subarctic peatlands in discontinuous permafrost regions are undergoing s

Global warming will bring about changes in surface energy balance of Arctic ecosystems, which will have implications for ecosystem structure and functioning, as well as for climate system feedback mechanisms. In this study, we present a unique, long-term (2000-2010) record of summer-time energy balance components (net radiation, R-n; sensible heat flux, H; latent heat flux, LE; and soil heat flux,

This study analyses the effects of thinning on stand transpiration in a typical mixed spruce and pine forest in the southern boreal zone. Studies of transpiration are important for models of water, energy and carbon exchange, and forest management, like thinning, would change those processes. Tree transpiration was measured by the tissue heat-balance sapflow technique, on a reference plot and a th

The formation of drops is a topic of great interest in a wide variety of engineering applications, such as membrane emulsification. In order to develop an improved force balance model that is capable of predicting the final size of the detached drop, the formation of drops into a cross-flowing continuous phase has been studied with computational fluid dynamics (CFD). The force balance developed ta

Local agricultural emissions contribute significantly to the atmospheric reactive nitrogen loads of Danish terrestrial ecosystems. In the vicinity of the sources this may be up to 6-8 kg N ha(-1) yr(-1) depending on location and ecosystem type. This contribution arises from dry deposition of gas phase ammonia derived from local livestock production. Long-range transport, however, often constitutes

The hygroscopic properties play a vital role for the direct and indirect effects of aerosols on climate, as well as the health effects of particulate matter (PM) by modifying the deposition pattern of inhaled particles in the humid human respiratory tract. Hygroscopic Tandem Differential Mobility Analyzer (H-TDMA) instruments have been used in field campaigns in various environments globally over

This thesis explores the impact of past and present landscape and habitat structure on present levels of vascular plant species diversity within fragmented semi-natural grasslands. Within the Jordtorp-area, a mosaic agricultural landscape on the island of Öland (Sweden), historical land-use changes and the development of semi-natural grasslands was characterized, over a time-period of almost 300 y

Snow cover plays a major role in the climate, hydrological and ecological systems of the Arctic and other regions through its influence on the surface energy balance (e.g. reflectivity), water balance (e.g. water storage and release), thermal regimes (e.g. insulation), vegetation and trace gas fluxes. Feedbacks to the climate system have global consequences. The livelihoods and well-being of Arcti

Monitoring high latitude wetlands is required to understand feedbacks between terrestrial carbon pools and climate change. Hydrological variability is a key factor driving biogeochemical processes in these ecosystems and effective assessment tools are critical for accurate characterization of surface hydrology, soil moisture, and water table fluctuations. Operational satellite platforms provide op

Drought is arguably the most important regulator of inter-annual variation in net ecosystem CO2 exchange (NEE) in peatlands. This study investigates effects of drought periods on NEE and its components, gross primary production (GPP) and ecosystem respiration (R-eco), on the basis of eddy covariance measurements of land-atmosphere exchange of CO2 in 2006-2009 in a south Swedish nutrient-poor peatl

Isomeric states in the semimagic Sn128-130 isotopes were populated in the fragmentation of a Xe-136 beam on a Be-9 target at an energy of 750 A.MeV. The decay of an isomeric state in Sn-128 at an excitation energy of 4098 keV has been observed. Its half live has been determined to be T-1/2 = 220(30) ns from the time distributions of the delayed gamma rays emitted in its decay. gamma gamma coincide

The main objective of this thesis was to quantitatively estimate the gaseous exchange of carbon dioxide (CO2) and methane (CH4) between a subarctic wetland ecosystem and the atmosphere. Additionally some initial estimates of the carbon input to the atmosphere of nonmethane hydrocarbons (NMHCs) were also obtained by combining different techniques in a joint setting. The data presented were collecte

The high-pressure homogenizer emulsification modelling framework by Håkansson et al. (2009a,Chemical Engineering Science 64, 2915–2925; 2009b. Food Hydrocolloids 23, 1177–1183), is further developed in this study. The model, including the simultaneous fragmentation of drops, coalescence of drops and kinetic adsorption of macromolecular emulsifiers, is improved with regard to two points.First, the

In this study, asymmetrical flow field-flow fractionation (AF4) coupled online with UV, multiangle light scattering (MALS), and fluorescence (FS) detectors (AF4-UV-MALS-FS) was employed for separation and characterization of egg yolk plasma. AF4 provided separation of three major components of the egg yolk plasma i.e. soluble proteins, low density lipoproteins (LDL) and their aggregates, based on

tmospherically important data are gained from cloud condensation nucleus counter (CCNC) analysis of aerosols that are particle mobility separated using differential mobility analysers (I)MA). We present relaxed step functions that can be fitted to these data to obtain critical diameters or critical supersaturations. The step functions are based on the DMA transfer function. We treat the case with

Sophisticated statistical analyses are common in ecological research, particularly in species distribution modeling. The effects of sometimes arbitrary decisions during the modeling procedure on the final outcome are difficult to assess, and to date are largely unexplored. We conducted an analysis quantifying the contribution of uncertainty in each step during the model-building sequence to variat