Search

Abstract: Significant resources are spent on counteracting the effects of acidification, mainly by liming. Due to lower S and N deposition in Europe and North America, authorities are changing directives and strategies for remediation and reducing liming. However, as the acid–base buffer capacity differs in different water bodies, the desirable reduction of the lime dose is variable. In this study, a geochemical model is used to predict pH and inorganic monomeric Al (Ali) when liming is reduced and finally terminated in the 3000 Swedish lakes currently treated with lime. To estimate Ca and Mg concentrations not affected by liming for use in the model, the Ca/Mg ratio in nearby unlimed reference lakes was used. For the modelling of pH and inorganic Al the Visual MINTEQ program including the Stockholm Humic Model recently calibrated for Swedish fresh water was used. The predictions were validated with modelling results from six monitored lakes, in which liming had been terminated. The use of geochemical modelling appeared to be a promising tool for the calculation of accurate lime requirements in acid waters. For simulations in which liming was completely terminated, the pH value decreased by, on average, 1 pH unit to pH 5.7, whereas Ali increased by 17μgL−1 to 32μgL−1. If liming was reduced by half, the pH would drop only 0.3 pH units and Ali would increase by 2μgL−1. Lakes in the south-western part of Sweden were predicted to reach a lower pH and higher Ali, which would be expected due to their greater historical S deposition. The results indicate that liming can be terminated in certain areas and in other areas be reduced without increases in the lake acidity. [Copyright &y& Elsevier]

The Bothnian Sea which is located between Finland and Sweden represents an important source of fresh water to the Baltic Sea. We here present new data on the radioactive isotope I species from water samples collected in December 2009 at different depths in the Bothnian Sea. Concentrations of I (iodide) in the Bothnian Sea range from 14 × 10 to 32 × 10 atoms/L, while IO (iodate) concentrations are relatively low and fluctuating at 1 × 10 atoms/L. For nutrients data determined in the same samples as I, significant correlations could be found between I and total P, NO-N, SiO-Si, but rather poor with NH-N. The correlations suggest comparable source pathway of I and nutrient parameters, while the source of NH-N may be different. The small amounts and negligible change of IO indicate prevailing extensive reduction of iodate in the Baltic Sea. [ABSTRACT FROM AUTHOR]

Abstract: The present study investigates the effect of several experimental iron-based granules on biomass tar decomposition. The iron-based materials were provided by Höganäs AB and were all in their metallic state when they were applied in a secondary catalytic reactor. Bark-free birch was employed as fuel in an atmospheric fluidised bed reactor, and the tar concentration and gas composition in the producer gas were measured before and after the catalytic bed. The results demonstrate a clear tar reduction capacity for all the tested iron-based materials. [Copyright &y& Elsevier]

Abstract: This paper reviews 17 measures to reduce phosphorus leakage from Swedish agriculture to surface waters. Our aim is to evaluate the possible contribution from agriculture to achieve environmental goals including the Baltic Sea Action Plan. Using a regional approach integrating the variability in field specific characteristics, typical costs and national potential for the included measures may be estimated without identifying, e.g., suitable individual fields for implementation. The result may be helpful to select suitable measures but may also influence the design of environmental targets before they are determined. We find that the cheapest measures are reduced phosphorus content in animal food and fertilizer application supervision in pig farms, both measures with annual potentials of around 50t each, and costs of €7 to €11kg−1 yr−1. The total potential of the listed measures is an annual phosphorus reduction to surface waters of 242t. If the most expensive measures are excluded (>€1000kg−1 yr−1) and including retention in lakes the phosphorus transport to the sea could be reduced by 165tyr−1. This amount can be compared with the Swedish commitment in the Baltic Sea Action Plan (BSAP) to reduce input to the Baltic Proper by 290tyr−1. [Copyright &y& Elsevier]

Cyanobacteria colonizing the feather moss Pleurozium schreberi were isolated from moss samples collected in northern Sweden and subjected to physiological and molecular characterization. Morphological studies of isolated and moss-associated cyanobacteria were carried out by light microscopy. Molecular tools were used for cyanobacteria identification, and a reconstitution experiment of the association between non-associative mosses and cyanobacteria was conducted. The influence of temperature on N2 fixation in the different cyanobacterial isolates and the influence of light and temperature on N2-fixation rates in the moss were studied using the acetylene reduction assay. Two different cyanobacteria were effectively isolated from P. schreberi: Nostoc sp. and Calothrix sp. A third genus, Stigonema sp. was identified by microscopy, but could not be isolated. The Nostoc sp. was found to fix N2 at lower temperatures than Calothrix sp. Nostoc sp. and Stigonema sp. were the predominant cyanobacteria colonizing the moss. The attempt to reconstitute the association between the moss and cyanobacteria was successful. The two isolated genera of cyanobacteria in feather moss samples collected in northern Sweden differ in their temperature optima, which may have important ecological implications. [ABSTRACT FROM PUBLISHER]