GACR

Forest ecosystems of the Czech Republic were exposed to a high level of pollutant deposition originating from coal burning in the 20th century. But studies investigating the fate of contaminants, such as toxic mercury, in the environment have been rather scarce. This project aims to explore the fate of mercury in forest ecosystems and its transformation to the highly toxic methylmercury in soils of two contrasting sites at the pristine Bohemian Forest and relatively polluted Beskids Mountains. We will fill a gap in the knowledge of historical deposition in northeastern Moravia through analysis of peat cores. Because the level of mercury deposition is an important parameter affecting the methylation processes, we will evaluate current mercury deposition at both sites and compare it to a reference site. Finally, forests at both contrasting study areas were subject to forest decline in the past decade due to insect infestations. Thus another aspect of this study will be to assessthe effect of forest dieback on methylation processes in polluted and unpolluted regions.

The aim is to contribute the global definition of the Jurassic-Cretaceous boundary integrating magnetostratigraphy, biostratigraphy, geochemistry and sedimentology data. Supplementary data and their evaluation enable to obtain accurate high-resolution stratigraphic schemes with high potential for multi-proxy correlation of selected regions, and sooner or elsewhere studied areas with marine sequences. The data will serve for the creation of database of integrated stratigraphy. Key sections of the research are Isle of Purbeck (England), Le Chouet and St Bertrand's Spring (France), Kurovice and Štramberk (Czech Republic). The correlation of sub-Boreal (Purbeck) and Tethyan regions (sections at Bosso - Italy, Puerto Escano - Spain, Brodno – Slovakia, Barlya – Bulgaria, Fedosiya – Crimea, Mezatepec - Mexico) is of special importance. The research will be carried out in the cooperation with the International Subcommission on Cretaceous Stratigraphy and thus contributing the definition of the boundary, which remains the last boundary of geological formations without global stratotype.

Acoustic emission (AE) is the process accompanying the brittle fracturing of solid body and simultaneously an indispensable tool for its study. Laboratory experiments under controlled loading conditions make it possible to differentiate the effect of important factors like material structure, stress field, crack presence, etc. on fracture initiation and development, and allow simulate the nature in situ. We will detect and classify the shear and tensile modes of rock fracturing by inverting the AE data gathered using a multichannel AE event recording system. The goal is to reveal mutual influence of rock structure and stress orientation, as well as the impact of microcrack concentration and orientation on the fracture mode changes. A novel source model consisting straight from the individual fracture modes will be applied for inversion of AE data, which is more robust in contrast to the traditional moment tensor against common deficiencies in the setup of the inverse task, like noise in the data, mislocation, inexact velocity model and sparse configuration of the sensors.

Ecosystems of the Planet Earth are contaminated by toxic elements, major part of which is usually of anthropogenic origin. Although natural cycle of mercury (Hg) was not affected as much by anthropogenic activities as i.e. cycle of lead, its effects on human health and health condition of ecosystems is incomparable. The environment of the Czech Republic is bearing several loads, which originate in its past industrial processing, similarly to selected areas in Poland or Germany. A complex study of the mercury behavior in forest ecosystems of the Czech Republic is thus needed. The data on accumulation or export of mercury from the ecosystems are also unsatisfactory. Existing data on the mercury content in top horizons of forest soils indicate significant contamination, namely in the central Czech Republic. This biogeochemical study aims to evaluate the mercury concentrations and pools in the compartments of the forest ecosystem.

According to present knowledge, the actually used provisional Boreal and the Tethyan J/K boundaries are heterochronous. All attempts to correlate the boundary J/K beds between the Boreal and the Tethyan realms by biostratigraphic methods failed. The aim of the project is to make a detailed and precise correlation of the J/K boundary interval in the Tethyan and Boreal region on the paleomagnetic (localization of reversed subzones) and geochemical base (included the isotope geochemistry and neutron activated analyses). On several pilot localities in the Tethyan region (e.g. Bosso-Italy, Brodno-Slovakia, Puerto Escaňo-Spain) was already successfully used for correlation the high resolution magnetostratigraphy together with detailed microbiozonation.On the only known J/K boundary section without hiatuses in the Boreal realm - Nordvik peninsula in Russia - was successfully elaborated by high resolution magnetostratigraphy together with ammonite biostratigraphy. The project use the methods of high

A multi-disciplinary study of fluvial, paralic and shallow-marine depositional systems of the Cenomanian age of the Bohemian Cretaceous Basin (BCB), Czech Republic combines methods of sequence stratigraphic analysis based on well-log, core and outcrop data, with paleontological and structural analysis, to obtain a detailed picture of evolution of depositional systems and their geometries in space and time. The geometries of Cenomanian strata deposited during the initial phase of basin evolution provide a direct link to the kinematic behaviour of basement structures - especially the Saxothuringian/Tepla-Barrandian suture and the Elbe Fault Zone during the Cretaceous reactivations - and the possible involvement of eustatic fluctuations of variousfrequencies. The research will focus of assessing the relative roles of tectonics and eustatic sea-level change in creating and filling accommodation in an intracontinental basin. This study will also contribute to better understanding of the mechanisms

The proposed research project is aimed at studying the process of rock fracturing in a regime of controlled speed of deformation and a regime of controlled stress during long-term sample loading. The project's starting point consists in a knowledge concerning stress-strain properties of rocks from the ultradeep Kola borehole, plus experience from a study of the process of rock fracturing by means of the statistical methods analyzing sequences of ultrasonic emission. Envisaged research into rock fracturing will proceed from determination of the mechanism of microcracks. Experiments will last from tens of hours up to first hundreds of hours from the onset of loading until final failure. A comparison of the fracturing of analogues of mantle-derived rocks with those in the upper crust may yield new findings on the impact of paleostress on the rock material's ability to accumulate and release energy during brittle fracturing. In methodological terms, the study of rock deformation will

The project is aimed at taphonomic and palaeoecological studies of echinoderms (echinoids, crinoids, asteroids), sponges and brachiopods, and, to a lesser degree, at some other components of the Late Turonian taphocoenoses of the hemipelagic facies in the Ohře region and the siliciclastic facies in the Jizera region, Bohemian Cretaceous Basin (BCB). The most important studied faunal groups will be also taxonomically evaluated. A crucial locality of the project, the Úpohlavy quarry near Lovosice, is relatively well known regarding the geology and stratigraphy.  The conclusions, together with data on ichnology and ichnofabrics, will largely improve our knowledge of sedimentary environments.  Stratigraphic correlations will be based on inoceramids, cephalopods, foraminifers and palynomorphs. Biostratigraphic value of some irregular echinoids (especially Micraster) commonly used in the west European Cretaceous zonation will be tested for the BCB.

The goal of the proposed project is to analyse the functional morphology and taphonomy of microscopical and macroscopical rests of fossils and their assignment to the basic categories of the trophic web. Such a assignment to individual categories makes possible to reconstruct relations of Lower Cambrian to Middle Ordovician organisms of the Barrandian area. The project will provide a model of relations within the Cambrian to Middle Ordovician ecosystem within six selected assemblages. Planctonic and benthic primary producers of the organic matter served as a basis of the trophic pyramide, which was used by different types of consumers (filtrating echinoderms, hyolithids, brachiopods etc.). Such an analyse coud use the already existing data about frequency of separate taxa and functional morphology existing for some groups of invertebrates (e.g. trilobites, hyolithids, brachiopods, echinoderms).

Next to the classical occurrences in southern Bohemia, western Moravia, northern Austria and Lusatia (Germany), moldavites were found also in the Pliocene sediments in the Cheb Basin. Compared to other localities only a littte is known about the chemicalcomposition of moldavites from this region so far: totally four pieces were analyzed for major elements only using electron microporobe techniques. The aim of the project is to provide as complete as possible chemical characteristics of the moldavites from this region based on more representative sample collection. No trace and minor element determination for the moldavites from the Cheb Basin exists so far - the data proposed to be yielded in the framework of this project will represent the first such determination ever. The detailed chemical composition study will reveal the mutual relationships to Bohemian. Moravian, Lusatian and Austrian moldavites which are not clear at the moment.