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Prague, Czech Republic

Kodesova R.,Czech University of Life Sciences | Nemecek K.,Czech University of Life Sciences | Zigova A.,Institute of Geology of the CAS | Nikodem A.,Czech University of Life Sciences | Fer M.,Czech University of Life Sciences
Biologia (Poland) | Year: 2015

Plants influence the water regime in soil by both water uptake and an uneven distribution of water infiltration at the soil surface. The latter process is more poorly studied, but it is well known that roots modify soil structure by enhancing aggregation and biopore production. This study used a dye tracer to visualize the impact of plants on water flow in the topsoil of a Greyic Phaeozem. Brilliant blue was ponded to 10 cm height in a 1 m x 1 m frame in the field immediately after harvest of winter wheat (Triticum aestivum L.). After complete infiltration, the staining patterns within the vertical and horizontal field-scale sections were studied. In addition, soil thin sections were made and micromorphological images were used to study soil structure and dye distribution at the microscale. The field-scale sections clearly documented uneven dye penetration into the soil surface, which was influenced by plant presence and in some cases by mechanical compaction of the soil surface. The micromorphological images showed that root activities compress soil and increases the bulk density near the roots (which could be also result of root water uptake and consequent soil adhesion). On the other hand in few cases a preferential flow along the roots was observed. © Institute of Molecular Biology, Slovak Academy of Sciences 2015.

Ludvikova J.,Czech Institute of Chemical Process Fundamentals | Jiratova K.,Czech Institute of Chemical Process Fundamentals | Klempa J.,Czech Institute of Chemical Process Fundamentals | Boehmova V.,Institute of Geology of the CAS | Obalova L.,VSB - Technical University of Ostrava
Catalysis Today | Year: 2012

Catalytic activity of the Co-Mn-Al mixed oxide catalysts (Co:Mn:Al molar ratio of 4:1:1) supported over titania was examined in total oxidation of ethanol. The prepared catalysts were characterized by chemical analysis (AAS), surface area measurements, and temperature programmed techniques (TPR, TPD). In ethanol oxidation, the catalysts activity gradually increased with increasing active phase content. Low concentration of Co-Mn-Al oxides in the catalyst negatively affected formation of reaction byproducts: carbon monoxide production steeply increased when Co + Mn metals concentration were lower than 5 wt.%. On the other hand, formation of the second main reaction intermediate, acetaldehyde was limited, when acidity of the catalyst was not high, i.e. concentration of Co-Mn metals over titania was low. © 2011 Elsevier B.V. All rights reserved.

Bella P.,State Nature Conservancy of the Slovak Republic | Bella P.,Catholic University in Ruzomberok | Bosak P.,Institute of Geology of the CAS
Acta Carsologica | Year: 2015

Ceiling channels belong to specific geomorphological forms occurring only in caves. Their origin has been commonly connected with the paragenesis. According to review articles, the terms of ceiling channel and paragenesis were defined by Philippe Renault (1958) for the first time. Nevertheless, Zdeněk Roth in his study of morphology and geomorphological evolu­tion of the Domica Cave (southern Slovakia) published in 1937 (in Czech with long French summary) not only described ceil­ing channels, but he presented also their definition. Roth and other authors used the term later in describing features of sev­eral caves in Slovakia and Hungary. Based on original Roth ob­servations, Josef Kunský defined the term generally in his text­book (1950 in Czech, 1956 in Polish and 1958 in French). The description of paragenetic ceiling channels by Renault (1958) can be considered as the first one only in Western European karstology literature. © 2015 Zalozba Z R C. All rights reserved.

Zigova A.,Institute of Geology of the CAS | Stastny M.,Institute of Geology of the CAS
Acta Geodynamica et Geomaterialia | Year: 2015

The development of soil cover on loess in regions of Cretaceous sediments and Devonian limestones in the Bohemian Massif was analysed. The study was performed in areas with different land use. Parent material was characterized on the basis of thin section study. Soils were evaluated by macromorphological analysis, particle size distribution, chemical properties, parameters of soil organic matter and mineral composition of clay fraction. The results revealed differences in the formation of soil cover which are predominately connected with geological conditions. The main pedogenetic process for Bohemian Cretaceous Basin is humification. Pedogenetic clay differentiation is relatively slight. Intense pedogenetic clay differentiation, less pronounced processes of litter formation and humification are characteristic for soils in the Devonian limestone areas. The intensity of processes of pedogenetic clay differentiation is influenced by pH values. The quality and quantity of soil organic matter were influenced by the source of biomass, biological activity and type of land use. Petrography of parent material from thin sections shows some differences among features of Ck horizons. The most abundant minerals of clay fraction of the studied soil are quartz, illite and kaolinite. Bt horizons of Albic Luvisols have an elevated content of illite. © 2015 Academy of Sciences of the Czech Republic. All Rights Reserved.

Navratil T.,Institute of Geology of the CAS | Shanley J.,U.S. Geological Survey | Rohovec J.,Institute of Geology of the CAS | Oulehle F.,Czech Geological Survey | And 4 more authors.
Journal of Geochemical Exploration | Year: 2015

The Czech Republic was heavily industrialized in the second half of the 20th century but the associated emissions of Hg and S from coal burning were significantly reduced since the 1990s. We studied dissolved (filtered) stream water mercury (Hg) and dissolved organic carbon (DOC) concentrations at five catchments with contrasting Hg and S deposition histories in the Bohemian part of the Czech Republic. The median filtered Hg concentrations of stream water samples collected in hydrological years 2012 and 2013 from the five sites varied by an order of magnitude from 1.3 to 18.0ngL-1. The Hg concentrations at individual catchments were strongly correlated with DOC concentrations r from 0.64 to 0.93 and with discharge r from 0.48 to 0.75. Annual export fluxes of filtered Hg from individual catchments ranged from 0.11 to 13.3μgm-2yr-1 and were highest at sites with the highest DOC export fluxes. However, the amount of Hg exported per unit DOC varied widely; the mean Hg/DOC ratio in stream water at the individual sites ranged from 0.28 to 0.90ngmg-1. The highest stream Hg/DOC ratios occurred at sites Pluhův Bor and Jezeří which both are in the heavily polluted Black Triangle area. Stream Hg/DOC was inversely related to mineral and total soil pool Hg/C across the five sites. We explain this pattern by greater soil Hg retention due to inhibition of soil organic matter decomposition at the sites with low stream Hg/DOC and/or by precipitation of a metacinnabar (HgS) phase. Thus mobilization of Hg into streams from forest soils likely depends on combined effects of organic matter decomposition dynamics and HgS-like phase precipitation, which were both affected by Hg and S deposition histories. © 2015 Elsevier B.V.

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