Trends and evolution of contamination in a well-dated water reservoir sedimentary archive: the Brno Dam, Moravia, Czech Republic

The sedimentary record from dams can provide important information about stratigraphy and pollution history of densely populated river basins. The Brno Dam is a small reservoir within the Morava River catchment (Czech Republic) accumulating lacustrine sediments since 1940 (dam filling). The stratigraphy of the dam sediments was studied using multiproxy stratigraphic analysis (X-ray densitometry, bulk magnetic susceptibility, diffuse spectral reflectance and cation-exchange capacity) of five sediment cores supported by ground-penetration radar sections. Concentrations of heavy metals were studied by X-ray fluorescence analysis. The thickness of the dam sediments decreases from 220 cm in the proximal part, near the feeder, to only 10 cm in the distal part, near the dyke. Sediments consist predominantly of finely-laminated silty sands, silts and clays. The sedimentation rate for the last ~22 years, inferred from ¹³⁷Cs dating, decreases from 4.2 cm per year in the proximal part of the dam to 0.29 cm per year in its distal part. Distinct long-term trends were found in the depth profiles of heavy metal concentrations. The heavy metal contents increase significantly after 1940 in all cores, with peak concentrations confined to layers deposited in the 1960s and 1980s. A decreasing trend occurred after 1989 (the decline in Czech heavy industry). The results also show that heavy metal contamination is dependent on lithology (hyperpycnal flow layers related to floods). Increased concentrations of phosphorus in the sediments indicate long-term eutrophication of the dam. Despite the recent decreasing trends in heavy metal concentrations the phosphorus contents remain high in recent years and have caused persisting problems with algal growth in the dam mentioned by previous authors.     

Determination of ecological significance based on geostatistical assessment: a case study from the Slovak Natura 2000 protected area

The Sitno Natura 2000 Site covers an area of 935,56 hectares. The Sitno region is significant due to the number of rare and endangered species of plants, and as a result is considered a location of great importance to the maintenance of floral gene pools. The study area suffers human impacts in the form of tourism. The main purpose of this study is to the measure landscape elements, determine the ecological significance of habitats within the Sitno area, and from this data, organize the study area into conservation zones. The results of this landscape quantification are numerical values that can be used to interpret the quality of ongoing ecological processes within individual landscape types. Interpretation of this quantified data can be used to determine the ecological significance of landscapes in other study areas. This research examines the habitats of Natura 2000 Sites by a set of landscape metrics for habitat area, size, density, and shape, such as Number of patches (NP), Patch density (PD), Mean patch size (MPS), Patch size standard deviation (PSSD) and Mean shape index (MSI). The classification of land cover patches is based on the Annex Code system.     

Cation exchange capacity of loess and overlying soil in the non-carbonate loess sections, North-Western Croatia

The adsorption properties in terms of cation exchange capacity and their relation to the soil and sediment constituents (clay minerals, Fe-, Mn-, and Al-oxyhydroxides, organic matter) were investigated in loess, soil-loess transition zone, and soil at four loess-soil sections in North-Western Croatia. Cation exchange capacity of the bulk samples, the samples after oxalate extraction of Fe, Mn and Al, and after removal of organic matter, as well as of the separated clay fraction, was determined using copper ethylenediamine. Cation exchange capacity (pH～7) of the bulk samples ranges from 5 to 12 cmol _c /kg in soil, from 7 to 15 cmol _c /kg in the soil-loess transition zone, and from 12 to 20 cmol _c /kg in loess. Generally, CEC values increase with depth. Oxalate extraction of Fe, Mn, and Al, and removal of organic matter cause a CEC decrease of 3–38% and 8–55%, respectively, proving a considerable influence of these constituents to the bulk CEC values. In the separated clay fraction (<2 μm) CEC values are up to several times higher relative to those in the bulk samples. The measured CEC values of the bulk samples generally correspond to the clay mineral content identified. Also, a slight increase in muscovite/illite content with depth and the vermiculite occurrence in the loess horizon are concomitant with the CEC increase in deeper horizons, irrespective of the sample pretreatment.     

Variations of Magnetic Bright Point Properties with Longitude and Latitude as Observed by Hinode/SOT G-band Data

Small-scale magnetic fields can be observed on the Sun in high-resolution G-band filtergrams as magnetic bright points (MBPs). We study Hinode/Solar Optical Telescope (SOT) longitude and latitude scans of the quiet solar surface taken in the G-band in order to characterise the centre-to-limb dependence of MBP properties (size and intensity). We find that the MBP’s sizes increase and their intensities decrease from the solar centre towards the limb. The size distribution can be fitted using a log–normal function. The natural logarithm of the mean (μ parameter) of this function follows a second-order polynomial and the generalised standard deviation (σ parameter) follows a fourth-order polynomial or equally well (within statistical errors) a sine function. The brightness decrease of the features is smaller than one would expect from the normal solar centre-to-limb variation; that is to say, the ratio of a MBP’s brightness to the mean intensity of the image increases towards the limb. The centre-to-limb variations of the intensities of the MBPs and the quiet-Sun field can be fitted by a second-order polynomial. The detailed physical process that results in an increase of a MBP’s brightness and size from Sun centre to the limb is not yet understood and has to be studied in more detail in the future.     

Comparison of two different solutions to Molodensky’s G1 term

The main purpose of this paper is comparison of two different approaches of solution to the Simple Molodensky’s Problem, the Molodensky’s Approach and the Analytical Continuation Approach, based on numerical computation. Although these approaches have been described theoretically by several authors, e.g. Molodensky et al. (1960), Heiskanen and Moritz (1967), Vaníček (1974), Moritz (1980) and Holota (1991, unpublished results) and theoretical proof of equivalence was given by Heiskanen and Moritz (1967), Moritz (1971), Ecker (1971) and Pellinen (1972, unpublished results), only very few practical experiences about the differences between particular solutions and computational efficiency exist. In this paper we compare the above two mentioned approaches in terms of the G₁-effect on quasigeoid. Both quasigeoid solutions are tested by the independent GPS/levelling approach and are also compared with the previous quasigeoid model of Slovakia where the G₁-term has been approximated using the classical terrain correction. The effect of the G₂-term is also numerically estimated, revealing that it might be significant for the precise quasigeoid determination. Some practical comments and recommendations are given at the end of the paper.     

Azimuthal anisotropy of the Pg-wave velocity in hypocentral volumes of NW Croatia

Based on a large set of arrival times of the Pg phase reported by local and regional stations, we estimate azimuthal anisotropy of the Pg-wave velocity in focal volumes of the upper crust in NW Croatia. The method is based on analyses of the azimuthal dependence of ratios of cumulative differences of arrival times and travel paths between foci of earthquake pairs, computed for rays propagating within narrow azimuthal windows. The results clearly indicate the presence of anisotropy of 3.3% with the direction of fast velocity (approximately NNE-SSW) coinciding with the direction of the maximum tectonic pressure as revealed by 23 available focal mechanisms and previous geological investigations. Although a large part of observed anisotropy can be explained assuming that focal volumes are pervaded by a system of vertical extensive-dilatancy anisotropy (EDA) cracks aligned under the influence of local tectonic stress field, there is indication that — to a smaller extent — some role was also played by alignment of structural features in the region.     

Earthquake Swarms and Accompanying Phenomena in Intraplate Regions: A Review

The western part of the Bohemian Massif has played an exceptional role in recent geodynamic activity of the region. It is characterised by repeated occurrences of earthquake swarms and by other manifestations of deep tectonic processes (CO ₂ emissions, anomalous ³ He content, mineral waters, mofettes, etc.). The purpose of this paper is to introduce some other intraplate regions with earthquake swarm occurrence (French Massif Central; Colli Albani and Vulsini Mts., central Italy; Southern Apennines, Italy; the Danville and Long Valley regions, California; central Arkansas), and with artificially induced earthquake swarms (Larderello, Italy, geothermal field; Coso, California, geothermal field; NE Bavaria, Germany, deep drilling project). Although these areas represent different tectonic environments, the manifestations of recent geodynamic and/or man-made activity are similar in many aspects. This coincidence most probably issues from a common cause of both tectonic and artificially induced earthquake swarms – intrusions/injections of fluids. Since the regions with earthquake swarm occurrence of tectonic origin are situated as a rule in the close neighbourhood of Quaternary volcanoes, the intruding fluids seem to be derived from magma recently transported to upper crustal layers.     

Recent Climate Warming: Surface Air Temperature Series and Geothermal Evidence

Long-term (1961 – 1996) meteorological air temperature series together with the reconstructed ground surface temperature histories, obtained by inverting borehole temperature-depth profiles, were used to project regional patterns of the recent (climate) warming rate on the territory of the Czech Republic. The characteristic magnitude of the warming rate of 0.02 –0.03 K/yr was confirmed by the results of several years of monitoring the temperature in two experimental boreholes. The monitoring of shallow temperatures at depths of about 30 –40 m, i.e. below the reach of the seasonal surface temperature variations, can serve as an alternative tool of direct quantitative assessment of the present warming rate. The data also seem to sustain a potential man-made component contributing to the more pronounced recent warming rate observed in the areas of large agglomeration.     

Bioremediation perspective of historically contaminated sediment with polycyclic aromatic hydrocarbons

The purpose of the current study is to compare the influence of different aerobic conditions(biostimulation(BS),bioaugmentation(BA),and a combination of biostimulation and bioaugmentation(BB))on polycyclic aromatic hydrocarbons(PAH)degradation and compare the degraded amount with single step XAD-4 extraction as a new tool for bioavailability assessment for chronically contaminated sediment samples obtained from territory of Autonomous Province Vojvodina of Serbia(S1,S2,and S3).A great number of papers dealing with biodegradation of PAHs in spiked sediment or soil have been published,but to the authors’knowledge,a limited number of papers studied aged,historically polluted sediment and a sum of chosen U.S.Environmental Protection Agency(USEPA)PAHs.A significant reduction(up to67%)in PAH concentration was observed,while the percentage of reduction varied depending on the sediment sample and treatment used.BS treatment successfully stimulated growth of indigenous bacteria.Further,PAH-degrading strain Sphingomonas paucimobilis F8 inoculated in BA and BB treatment survived for up to 7 weeks after it was suppressed by unfavorable conditions or native microbes.Degraded amounts generally showed good correlation with results obtained from XAD-4 extraction.Results obtained in the current study represent a good start for standardizing a XAD-4 extraction technique as a simplified,easier,and lower cost method for bioavailability assessment.