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info:eu-repo/semantics/publishedVersion

info:eu-repo/semantics/publishedVersion

The saturated hydraulic conductivity of soil, Ks, is a critical parameter in hydrological models that remains notoriously difficult to predict. In this study, we test the capability of a model based on percolation theory and critical path analysis to estimate Ks measured on 95 undisturbed soil cores collected from contrasting soil types. One parameter (the pore geometry factor) was derived by model fitting, while the remaining two parameters (the critical pore diameter, dc, and the effective porosity) were derived from X‐ray computed tomography measurements. The model gave a highly significant fit to the Ks measurements (p < 0.0001) although only ~47% of the variation was explained and the fitted pore geometry factor was approximately 1 to 2 orders of magnitude larger than various theoretical values obtained for idealized porous media and pore network models. Apart from assumptions in the model that might not hold in reality, this could also be attributed to experimental error induced by, for example, air entrapment and changes in the soil pore structure occurring during sample presaturation and the measurement of Ks. Variation in the critical pore diameter, dc, was the dominant source of variation in Ks, which suggests that dc is a suitable length scale for predicting soil permeability. Thus, from the point of view of pedotransfer functions, it could be worthwhile to direct future research toward exploring the correlations of dc with basic soil properties and site attributes.

It is now evident that fresh- and marine-water ecosystems have long been overloaded by nutrients that originate, among others, from land-based agriculture, and the manifold point-type anthropogenic sources, such as waste-water treatment plants. The situation in this sense is rather acute in the Baltic countries and their waters. This situation will not improve until we identify the true sources and pathways of pollutants and quantify their contribution, advance our process-understanding to describe the mechanisms through which the pollution occurs, and by what steps we may be able to influence that, and quantify what, if any such steps – today popularly termed ‘mitigation measures’ – may produce certain levels of benefit sustainably. Various advancements have already been made in a number of the above steps, but the applied mitigation measures are often local and scarce, their effects are often influenced by other unknown and uncontrolled factors, and their installation is too recent to yield noticeable changes due to e.g. the nutrient retention characteristics of the ecosystem. It is therefore of paramount importance that we monitor and use environmental data towards long-term planning in order to sustain or improve the state of our environment. Environmental modeling is a growingly important tool for future planning. One main branch of such modeling – the use of process-based models – is a generally data intensive, but in exchange rather detailed way of quantifying natural processes. As part of the greater context of the NORRA project, this Working Group reports on its work towards (a) cataloguing existing environmental data for selected pilot-watersheds of Estonia that are needed to run process-based simulation models for those watersheds; (b) identifying suitable, and feasibly usable models, and calibrate, validate and test them under Estonian conditions; (c) evaluating the models’ performance and capability to become decision support tools; and (d) and advising on data and knowledge gaps towards further future progress.

As customer awareness grows, there is an increasing consumer demand for minimally processed food products containing reduced amounts of additives. In order to preserve the safety and stability of foodstuffs, the use of preservatives is necessary in most cases, but their amounts can be reduced or they can be replaced by using alternative preservatives. There are numerous research findings in the scientific literature that support the antimicrobial effect, oxidative stability and scavenger abilities of black cumin seed oil. These properties, combined with its beneficial physiological effects, make it particularly suitable for use as a natural preservative. The goal of this work was to investigate the antimicrobial effect of black cumin seed oil in the case of Staphylococcus aureus, a pathogen relevant from a food safety point of view. In order to be able to map the mode of action more accurately, we worked with erythromycin, and to test the suitability of the oil in a combined preservation process, it was combined with organic acids.