NE Czech Republic Research Articles

Seasonal oxidative dynamics and isotopic fractionation of NOx and SO2 in Ostrava, Czech Republic: Insights from stable isotope analysis

The city of Ostrava, NE Czech Republic, is known for its industrial pollution. It has well-characterized emission sources and stable air movement patterns. These features are conveniently used to generalize on atmospheric NOx and SO2 oxidation processes. In 2021, we conducted a series of sampling campaigns to assess the isotopic fractionation conducive to NO3− and SO42− aerosols in PM10. These sampling campaigns were timed to capture varying atmospheric conditions, including climatic inversion periods, providing also insights into urban emission dynamics over the course of the year. Gaseous NOx and SO2 were collected on passive filters, while their oxidized forms, NO3− and SO42, were captured on PM10 particle filters, enabling us to analyze the transformation dynamics of these pollutants. Isotopic analyses distinguished the sources of NOx emissions—coal combustion (δ15N = −3‰) and vehicular emissions (δ15N = −7 ‰)—and allowed quantifying isotope fractionation during their conversion to NO3− (εNOx-NO3- = 11.5 ± 1.15 ‰). This fractionation, however, was influenced by seasonal variations, and appears to be notably affected by NH4NO3 decomposition during warmer months. The correlation of the NO3− to NOx ratio with PM10 and atmospheric moisture highlighted the interplay between particulate matter and humidity in relevant atmospheric transformations. Similarly, for SO2, primarily emitted from coal combustion (δ34S = −2‰), we identified distinct fractionation patterns during oxidation to SO42− encompassing both kinetic (εSO2-H2O = −1.3 ± 0.5‰) and equilibrium (εSO2- SO42- = 2.24 ± 0.67‰) effects. The SO42−/SO2 ratio was correlated with PM10 but showed no dependence on humidity. Significantly, atmospheric inversion conditions accelerated oxidation, modifying the fractionation patterns for both NOx (εNOx-NO3- = 7‰) and SO2 (εSO2- SO42-= −0.9 ± 0.3‰). Our methodology elucidates pivotal mechanisms in atmospheric pollution transformation, underlined by the tracing of NOx and SO2 to aerosol conversions via δ15N and δ34S isotopic analyses. The isotope fractionation underscores equilibrium processes in oxidation reactions, while the effect of PM10 and humidity reveals the complexity of these atmospheric oxidative transformations. The role of wet deposition in removing SO2 highlights an essential pathway in the atmospheric sulfur cycle.

Methane anomaly in soil gas above an abandoned oil & gas exploration borehole in NE Czechia

In the 1950s–1960s, 71 coal and gas exploration wells were drilled in the area of interest in the Western Carpathian Flysch Belt (WCFB) in the NE Czech Republic. Some wells were abandoned while others were used for gas production and storage in the Třanovice underground gas storage (UGS). A monitoring campaign was carried out in place of an earlier abandoned exploration well Žu-108 aiming at proving or ruling out a geochemical relationship of the soil gas and the stored gas in the UGS. The measurements were carried out each month from June 2018 to October 2019 and included amount of methane (CH4), total petroleum gases (CH4 to C4H10), carbon dioxide (CO2) and oxygen (O2) in soil gas in a grid of up to 41 probes. The results show a methane gas peak occurrence with 10 m diameter around the well-top with maximum methane content of 57%vol, while the natural background value of methane content outside the plume is < 500 ppm. The position of the methane peak is associated with significant O2 drop down to 0.25%vol and is surrounded by up to 8.34%vol CO2 halo produced most probably by methanotrophic archea-bacteria. The natural background CO2 values are ca. 0.80%vol. CH4 flux to the atmosphere from the topsoil directly above the well-top of Žu-108 well was measured using the accumulation chamber and range from 2126 to 26 197 g d−1 m−2. The flux increased during drops in atmospheric pressure and ground water level in situ. In contrast, low methane flux was registered after strong rainfalls and when the soil was covered by ice and snow which acted as seal. Based on chemical composition and isotopic signature of methane, the gas is of oil-associated type and methane is thermogenic, similar to that of the original (i.e. pre-UGS) Žukov gas field as well as other small accumulations in the WCFB on the territory of the Czech Republic. It statistically differs from imported mixture of Siberian and Norwegian gas stored in the Třanovice UGS. Based on it, the possible natural gas leakage from the UGS to the Žu-108 is in this case ruled out.

New and interesting records of Diptera on glacial sand deposits in Silesia (NE Czech Republic). Part 3 – Acalyptratae 2

Abstract Additional records of 28 species of interest belonging to acalyptrate families Lonchaeidae (1 species), Lauxaniidae (2 species), Chamaemyiidae (9 species), Agromyzidae (16 species) and Opomyzidae (1 species) from glacial sand deposits in the Czech Silesia (NE Czech Republic) are presented and their association with sandy habitats discussed. A total of 25 species are recorded from the Czech Silesia for the first time, 15 are new additions to the fauna of Moravia of which 11 are also new for the whole of the Czech Republic. Six species (Lauxaniidae 1, Agromyzidae 5) are new additions to the Diptera fauna of Poland. Leucopis cerasiphila Gomolitzkaja &amp; Tanasijtshuk, 1986 is recorded for the first time from Europe. None of the here reported species is classified as psammobiont but 8 species are considered psammophilous or probably psammophilous, viz. Minettia longiseta (Loew, 1847) (Lauxaniidae), Leucopis kaszabi Tanasijtshuk, 1970 (Chamaemyiidae), Cerodontha (Xenophytomyza) leptophallus Papp, 2016, Hexomyza sarothamni (Hendel, 1923), Liriomyza dracunculi Hering, 1932, L. latigenis (Hendel, 1920), L. yasumatsui Sasakawa, 1972 (Agromyzidae) and Geomyza subnigra Drake, 1992 (Opomyzidae). The conspicuous species diversity of Chamaemyiidae in Silesian glacial sand deposits is discussed.

New and interesting records of Diptera on glacial sand deposits in Silesia (NE Czech Republic). Part 2 – Brachycera except for Schizophora

AbstractRecords of 19 species of the dipteran familiesBombyliidae(1 species),Mythicomyiidae(1 species),Therevidae(2 species),Empididae(3 species),Hybotidae(1 species),Dolichopodidae(8 species) andSyrphidae(3 species) from glacial sand deposits in the Czech Silesia (NE Czech Republic) are presented and their association with sandy habitats discussed. All of them are recorded from the Czech Silesia for the first time, 13 are new additions to the fauna of Moravia of which 9 are also new for the whole of the Czech Republic.Dialineura anilis(Linnaeus, 1761) (Therevidae) andSchistostoma truncatum(Loew, 1864) (Dolichopodidae) are classified as psammobiont, 6 species as psammophilous, viz.Exhyalanthrax afer(Fabricius, 1794) (Bombyliidae),Cliorismia rustica(Panzer, 1804) (Therevidae),Cryptophlebs kertesziLichtwardt, 1898,Melanostolus melancholicus(Loew, 1869) (both Dolichopodidae) andParagus constrictusŠimić, 1986 andPelecocera tricinctaMeigen, 1822 (Syrphidae), and 3 species as probably psammophilous, viz.Medetera annulitarsusvon Roser, 1840,M. gruniniNegrobov, 1966 andSciapus basilicusMeuffels &amp; Grootaert, 1990 (all Dolichopodidae).Medetera gruniniis recorded for the first time from Europe and represents a new westernmost limit of its distribution range in the Palaearctic. New southernmost records ofRhamphomyia murinaCollin, 1926 (Empididae) andDrapetis monsmargilaGrootaert, Beuk &amp; Shamshev, 2020 (Hybotidae) are also given.

First record of Microterys turanicus Sugonjaev, 1965 (Hymenoptera: Encyrtidae) from Europe

Abstract Microterys turanicus Sugonjaev, 1965 (Hymenoptera: Encyrtidae) is added to the fauna of the Czech Republic and the whole of Europe on the basis of a record from the Moravskoslezské Beskydy Mts, Morávka (North Moravia, NE Czech Republic). The distribution and biology are reviewed and notes on the identification of the species are given along with illustrations of its habitus and some diagnostic characters.

Spectral properties of Antarctic and Alpine vegetation monitored by multispectral camera: Case studies from James Ross Island and Jeseníky Mts.

In this study, we investigated the utility of spectral remote sensing data gathered by a multispectral camera for estimating of vegetation cover in Antarctic vegetation oasis and Arcto-Alpine tundra. The surveys exploiting unmanned aerial vehicles (UAV) and multispectral camera were done in an Antarctic vegetation oasis located at the Northern shore of James Ross Island (Antarctica), and arcto-alpine tundra located in the Jeseníky Mts. (NE Czech Republic, 1 420 m a.s.l.). For the two locations, false colour images of spectral indices (VARI, NGRDI, GLI, RGVI, ExG, NDVI, PRI) were taken and analysis of vegetation types and components of vegetation cover done. Additionally, field research was performed by handheld instruments measuring NDVI, PRI and of selected vegetation components: Bryum pseudotriquetrum, Nostoc commune colonies (Antarctica), lichens grown on flat stones and boulders (the Jeseníky Mts.). The results show UAV photo surveys and imaging of spectral reflectance indices can be used to monitor vegetation types forming Antarctic vegetation oases and arcto-alpine tundra.

New and interesting records of Diptera on glacial sand deposits in Silesia (NE Czech Republic). Part 1 - Acalyptratae

Abstract Records of 18 species of the families Micropezidae (1 species), Lonchaeidae (1 species), Lauxaniidae (1 species), Chamaemyiidae (6 species), Agromyzidae (6 species) and Chloropidae (3 species) from glacial sand deposits in the Czech Silesia (NE Czech Republic) are presented and their association with sandy habitats is discussed. All of them are recorded from the Czech Silesia for the first time, 4 are new additions to the fauna of Moravia and 9 for the whole Czech Republic. None of the recorded species is psammobiont but five of them are classified as psammophilous, viz. Micropeza lateralis Meigen, 1826 (Micropezidae), Calliopum geniculatum (Fabricius, 1805) (Lauxaniidae), Cerodontha (Xenophytomyza) leptophallus L. Papp, 2016, Ophiomyia disordens Pakalniškis, 1998 (both Agromyzidae), Aphanotrigonum parahastatum Dely-Draskovits, 1981 (Chloropidae), and Leucopis celsa Tanasijtshuk, 1979 as probably psammophilous. A new easternmost record of M. lateralis (from S. Poland: Godów) is presented and the association of this species and C. geniculatum with growths of Cytisus scoparius is confirmed. Leucopis monticola Tanasijtshuk, 1961, L. celsa and A. parahastatum are recorded from northernmost known localities. These species, and also C. (X.) leptophallus seem to be thermophilous and/or xerophilous and can be considered southern elements in the Silesian fauna of Diptera.

Characteristics of large wood in a headwater channel after an extraordinary event: The roles of transport agents and check dams

High-magnitude hydrogeomorphic events in steep streams (e.g., debris flows and debris floods) are capable of transporting considerable quantities of bed material, including large wood, although wood pieces that are longer than the channel width are often perceived as relatively stable elements in narrow headwater channels. We investigated present large wood distribution along 1.7 km of a steep headwater channel (the Klepáčský Stream; Eastern Sudetes; NE Czech Republic) surrounded by managed forests and engineered by twelve check dams (presently at various stages of destruction). The total wood volume was measured at 123.0 m3, including wood deposited on adjacent terraces by a high-magnitude hydrogeomorphic event in 2010 representing a ca. 20–30 year recurrence interval. Approximately a half of the total wood volume (58%) was stored in large jams (≥10 large wood pieces) that originated during that event. We observed reach controls (based on transport agents and valley morphology) and local controls (represented by individual check dams) of LW depositional patterns. The uppermost debris flow-affected reach produced high volumes of mobilised wood, including many pieces that were two-to-three times longer than the local active channel width; significantly shorter and thinner pieces were found within large jams in downstream reaches void of debris-flow processes. We also documented that this high-magnitude event was responsible for the notable out-of-channel storage of large wood, which decreases the volume of wood that might be transported by a future event. In addition, 30.5 m3 of large wood, that is ~one-quarter of the total volume measured along the stream, was deposited in relation to twelve damaged check dams despite their lowered trapping efficiency.

2D BASIN MODELLING IN THE EASTERN VARISCAN FOLD BELT (CZECH REPUBLIC): INFLUENCE OF THRUSTING ON PATTERNS OF THERMAL MATURATION

This study evaluates the geothermal history of Palaeozoic sedimentary rocks from the easternmost part of the Variscan external zone in the NE Czech Republic. The objective was to investigate the geothermal history of pre‐Variscan Palaeozoic carbonates in the study area, and to assess its relationship with that of the overlying Variscan flysch. In the study area, the Palaeozoic succession occurs at the surface or is overlain by Miocene sediments of the Carpathian Foredeep. Palaeozoic nappes and the main Variscan overthrust have been documented in the subsurface at the deep Potštát‐1borehole.Vitrinite reflectance measurements on 38 samples from the Potštát‐1 well and 19 samples from nearby surface outcrops and shallow boreholes were available. A 2D thermal model was created using PetroMod and the thermal maturity evolution was modelled by EASY%Ro. The thermal model was constructed based on interpretations of two NW‐SE seismic profiles (lines 5/83 and 5/84) oriented perpendicular to the main Variscan thrusts. The results were calibrated using measured vitrinite reflectance and were adjusted with 1D models from three shallow boreholes. At the Potštát‐1 borehole, modelled maximum palaeo‐temperatures of the Variscan flysch (Moravice Formation) ranged from 310°C at a depth of 7.3 km (the top of the preserved succession) to 395°C at the base of the succession, resulting in thermal maturities of &gt;4%Rr. Peak maturation occurred prior to the end of Variscan thrusting. Modelling suggests that the basal heat flow for these thrust units reached a maximum value of 63 mW/m2 at 325 Ma. In addition, the modelling suggests that the maturity of the Palaeozoic carbonates was controlled by the thickness of the overlying Variscan flysch nappes. Maximum palaeo‐temperatures for the Palaeozoic carbonates ranged from 265°C at the top of the interval (at a depth of 7.1 km) to 290°C at the base, resulting in a maturity of 3.8 to &gt;4%Rr which is within the dry gas window. The study suggests that basal heat flows in the original (pre‐thrust) Early Carboniferous sedimentary basin were slightly higher than those in the post‐thrust location for the Variscan flysch nappes. This should be taken into account when evaluating the petroleum system in the South Moravian oil province (SW Czech Republic) where a complete sedimentary sequence has not been preserved.

Post-Variscan thermal history of the Moravo-Silesian lower Carboniferous Culm Basin (NE Czech Republic - SW Poland)

Apatite fission track analysis (AFT) and zircon (U-Th)/He thermochronology (ZHe) have been carried out for a lower Carboniferous greywacke succession of the Moravo-Silesian Culm Basin in the Nízký Jeseník Mountains. The range of apparent zircon helium ages is 303–233Ma (late Carboniferous to Early Triassic) in the eastern part of the basin, whilst they are significantly younger in the western part, ranging from 194 to 163Ma (Early-Middle Jurassic). Apatite fission track central ages range from 152 (Latest Jurassic) to 44Ma (Eocene), with the majority being grouped between 114 (Aptian) and 57Ma (Paleocene). All samples experienced substantial post-depositional thermal reset; both the AFT ages and the ZHe are considerably younger than the depositional ages. The mean track length varies in the range between 12.5 and 15.4μm. The unimodal track length distribution, the relatively short mean track length (in most samples), and their rather low standard deviation values (1.2 to 2.1μm) indicate that their thermal history was determined by Variscan and post-Variscan heating event(s) followed by a prolonged residence in the apatite partial annealing zone in the Mesozoic and finally by cooling in the Paleogene. Geological evidence combined with thermal modeling based on AFT and ZHe data indicate that the lower Carboniferous strata had already reached maximum palaeotemperatures in the late Carboniferous, however, they were presumably later re-heated during the Permian-Triassic. Post-Variscan extensional tectonics events were responsible for high heat flow that together with Carboniferous burial could account for the reset of both thermochronometers. A major phase of cooling occurred in the Late Cretaceous. Finally, exhumation was probably faster in the Paleogene, causing the present-day exposure of the studied rocks.

A Landscape Reconstruction Algorithm and pedoanthracological data reveal Late Holocene woodland history in the lowlands of the NE Czech Republic

We aim to obtain composition of the regional vegetation from the pollen record in the high mountains, to use it in the interpretation of the pollen record from the lowlands via a Landscape Reconstruction Algorithm (LRA), and to then compare the pedoanthracological data with the LRA result based on dissimilarity coefficient.We used five pollen sequences from summits of the Eastern Sudetes (NE Czech Republic), and two pollen cores were analysed in the adjacent Litovelské Pomoraví lowlands. The same lowland woodland was sampled in six pedoanthracological sections. All records cover the Late Holocene period.Site-to-site variability of the pollen spectra from the mountains was found to be low. Regional vegetation inferred from shallowest pollen samples corresponds to present-day vegetation inferred from forestry data. Mountain sites represent regional components and can substitute for large sites in an LRA.Mean LRA estimates were more similar to mean charcoal spectra than they were to mean pollen percentages. LRA estimates of Quercus and Fraxinus in the lowlands match the pedoanthracological evidence regarding individual sites. LRA estimates and charcoal spectra both show that the main dominant (>50%) in the woodland studied was Quercus.Mismatching evidence resided in a small number of the determined charcoals and there were differences between some assumptions of the LRA and the real-world conditions. Alnus and Tilia produced higher pollen signals on the expanse of Fagus and Abies, which were recorded by charcoals within the Relevant Source Area of Pollen (RSAP), which varied from a 35 to a 255meter radius, and ranged with the value from forest hollows.Comparability of LRA vegetation estimates and charcoal percentages is still at the level of complementary evidence. However, a quantitative approach shifts the character to substitutable evidence, with potential to provide the same vegetation estimates by both proxies.

Recent spruce decline with biotic pathogen infestation as a result of interacting climate, deposition and soil variables

Decline or health deterioration of Norway spruce (Picea abies (L.) Karst.) dominated forest stands has recently been observed mainly in sub-mountainous parts of Central Europe. Forest inventory of 208 randomly distributed circular plots including field observations of spruce tree health and rot symptoms by honey fungus (Armillaria ostoyae) was used for assessing intensity of spruce forest health decline in a managed forest area of 12.7 th. ha located in Beskids Mts., NE Czech Republic. First, principal component analysis was used to separate inventory variables related to environmental stress (reduced apical increment, dry tree top and stem resin exudation due to A. ostoyae infestation) into PC1, and health deterioration symptoms associated with mechanical damage (peeling, crown breaks) into PC2. The first two principal components explained 59% of the total variability in health decline symptoms. Spatial variability of both principal components was explained using spatial lag regression model identified from a set of environmental variables including sulfur and nitrogen deposition, elevation, solar radiation, age of the forest stands and geological properties (geochemical reactivity index). Environmental stress (PC1) was associated with low elevations (sub-optimal for spruce), high level of nitrogen and sulfur deposition (their interaction), low geochemical reactivity and also stand age. On the other hand, mechanical damage (PC2) significantly increased with elevation and stand age. As the forest decline in Beskids Mts. is related to A. ostoyae spreading from local infestation hot spots, both principal components had a significant spatial autocorrelation, partly distorting the signal of environmental conditions. The results indicate that the disturbed forest soils by long-term acid deposition and subsequent nutrient degradation and more pronounced drought stress at low elevations are the most important drivers of the recent spruce health decline in Beskids Mts.

History of the Litovelské Pomoraví woodland (NE Czech Republic): A comparison of archaeo-anthracological, pedoanthracological, and pollen data

Although charcoal and pollen analyses have been used for many years for the reconstruction of the vegetation history, the combination and comparison of their records is still not commonly used. Our study focuses on the lowland region of Litovelské Pomoraví in NE Czech Republic, which is characterised by the presence of long-term human activities. The archaeo-anthracological records were used to reconstruct a species composition of woodland in the vicinity of archaeological sites. This vegetation was characterised by an abundant presence of heliophilous and stress tolerant arboreal taxa. The pedoanthracological record documented a history of local vegetation, which was usually more distant from archaeological sites. Although pedoanthracological profiles were excavated from analogical locations, with the recent dominance of Quercus, the species composition confirmed the importance of environmental differences in the vicinity of the localities. The cluster analysis of our charcoal dataset differentiated six woodland types in the study area, and the pollen analysis provided a record of the vegetation history from another habitat. The pollen analysis reveal not only closed local canopy vegetation but also influence of fire events and human impact on pollen rain. The cross-correlation of archaeo-anthracological, pedoanthracological and pollen data provided a comprehensive reconstruction and interpretation of the vegetation history of this lowland habitat.

Acalyptrate flies (Diptera) on glacial sand deposits in the Hlučínsko region (NE Czech Republic): most interesting records

Abstract Records of six species of the families Ulidiidae, Anthomyzidae, Asteiidae, Milichiidae, Chloropidae and Curtonotidae from glacial sand deposits in the Hlučínsko region (NW Czech Republic) are presented and their association with sandy habitats are discussed. Two thermophilous and/or xerophilous species, Anthomyza elbergi Andersson, 1976 (Anthomyzidae) and Desmometopa discipalpis Papp, 1993 (Milichiidae) represent new additions to the fauna of the Czech Republic. Two psammophilous or psammobiont species, Eutropha variegata Loew, 1866 (Chloropidae) and Curtonotum anus (Meigen, 1830) (Curtonotidae) are recorded for the first time from Moravia and the Czech Silesia respectively, the latter from a locality lying on northern border of its distributional range. Also Asteia elegantula Zetterstedt, 1847 (Asteiidae) is first recorded from the Czech Silesia and Desmometopa discipalpis is recorded from its northernmost known locality. Information on microhabitats of these species and also the psammobiont Tetanops myopina Fallén, 1820 (Ulidiidae) in sandpits are provided and most of them were photographed alive. The origins of populations of these species on glacial sands in the Hlučínsko region are discussed and it is concluded that while Asteia elegantula and Eutropha variegata are widespread in the W Palaearctic, Curtonotum anus and Desmometopa discipalpis are distinctly of southern origin and, most interestingly, Tetanops myopina and Anthomyza elbergi seem to originate from northern Europe and may have reached this area already during the Saalian glaciation (cca 160 000 ya).

Conditions for development of anthropogenic meromictic reservoirs in the workings of crystalline rocks (based on the examples of the quarries of the Žulovská pahorkatina, NE Czech Republic)

There are numerous anthropogenic water reservoirs in the vicinity of the Žulovská pahorkatina (northern Czech Republic). The vast majority of them have developed as a result of the flooding of the abandoned quarries of crystalline rocks (granites or granodiorites). The surface area of these water bodies is small and is <6000 m2. These are, however, very deep reservoirs of up to 25 m. Permanent water stratification has been recorded in some of them; these are meromictic reservoirs. The development of the phenomenon of meromixis in the reservoirs that were studied was conditioned by the supply of organic matter from the catchment. The biochemical process of organic matter decomposition led to the release of ions, mainly NH4 +. The accumulation of dissolved substances in the benthic zone initiated the meromixis phenomenon. Therefore, the water bodies that were tested can be classified as reservoirs of the biogenic type of meromixis. This article presents the stages of the evolution of a holomictic reservoir into a meromictic one. Three water bodies in which meromixis was recorded were selected for the study. The control object was an abandoned quarry reservoir with no meromixis.

Palaeoenvironmental change in the Early Cretaceous Silesian Basin of the Western Carpathians (NE Czech Republic) inferred from palynological data

A Berriasian–lowermost Cenomanian composite stratigraphic section of the Silesian Basin of the Outer Western Carpathians was studied palynologically with an emphasis on quantitative palynomorphs and dinoflagellate cyst distribution. The quantitative composition of the dinoflagellate cyst assemblages reflects a palaeoenvironmental change from inner neritic to outer neritic or oceanic conditions. This change is considered to reflect a relative rise in sea level (according to the 2nd order eustatic curve) and/or tectonic subsidence in the basin. In the lower part (Berriasian to Hauterivian), dinoflagellate cysts characterising a shallow-water environment with variable salinity dominate. The quantitative composition of the dinoflagellate cysts of the latest Hauterivian to early Aptian is characteristic of a deeper shelf environment. In the latest Aptian to Albian, there is already sedimentation in a basinal sedimentary environment (oceanic dinoflagellate cysts are present here as an autochthonous element), with the redeposition of material supplied from littoral to deeper shelf areas. For the composition of palynomorph assemblages, sporomorphs play a more important role in the period from the late Valanginian to the early Aptian. This role is proved by an increased supply of terrestrial material, and it corresponds to a higher amount of black claystones and sandstones.

Report on a recent deep-seated landslide at Gírová Mt., Czech Republic, triggered by a heavy rainfall: The Gírová Mt., Outer West Carpathians; Czech Republic

A large deep-seated landslide, triggered by a heavy rainfall, activated early in the morning on May 19, 2010 along the SW slope of Girova Mt., NE Czech Republic. The landslide occurred within a zone of pre-existing deep-seated gravitational deformation, and it was accompanied with pronounced ground liquefying in the central and lower portion of the sliding mass. The precipitation that triggered the landslide was about 244.6 mm that fell between May 15th and 18th with an average of 61 mm/day. No properties or lives were lost. However, the landslide provided a good case study on triggering factors and process of liquefaction at mountain slopes in the E Czech Republic and adjacent areas.

Dependence of the Q10 values on the depth of the soil temperature measuring point

The parameter Q10 is commonly used to express the relationship between soil CO2 efflux and soil temperature. One advantage of this parameter is its application in a model expression of respiration losses of different ecosystems. Correct specification of Q10 in these models is indispensable. Soil surface CO2 efflux and soil temperature at different depths were measured in a 21-year-old Norway spruce stand and a mountain grassland site located at the Experimental Ecological Study Site Bily Kriz, Beskydy Mts. (NE Czech Republic), using automated gasometric systems. A time-delay and goodness-of-fit between soil CO2 efflux and soil temperature at different measuring depths were determined. Wide ranges of values for the time-delay of CO2 efflux in response to temperature, Q10 and the determination coefficient (R2) between CO2 efflux and temperature were obtained at the both sites. The values of Q10 and the CO2 time-delay increased with depth, while the R2 of the CO2-temperature relationship significantly decreased. Soil temperature records obtained close to the soil surface showed the highest values of R2 and the lowest value of the time-delay at both sites. Measurement of soil temperature at very shallow soil layer, preferably at the soil surface, is highly recommended to determine useable values of Q10. We present a new procedure to normalize Q10 values for soil temperatures measured at different depths that would facilitate comparison of different sites.

Phragmites australis at an extreme altitude: Rhizome architecture and its modelling

In central EuropePhragmites australis is a lowland plant, occurring rarely up to the tree line. In the Velka Kotlina cirque (Jeseniky mountains, NE Czech Republic), where it reaches its maximum altitude at about 1350 m a.s.l., its culms are 0.5–0.7 m high and the plants flower only in some years. During the last decade no germinable seeds have been observed. The architecture ofPhragmites rhizomes from this site was studied on seven randomly selected clonal fragments. They consisted of 3 to 10 partial tussocks (clumps) and 4 to 17 green shoots. The total length of the rhizomes was 9.7 to 50 m per plant. The number of nodes per plant was 96 to 431 and the longest internodes were 83 mm long. The number of side branches was 31 to 105 per plant. The branching angle depended on the type of branched rhizome. The mean angles of horizontal rhizomes, which connect individual tussocks, were relatively wide (modus 45°, arithmetic mean 37°), whereas within a tussock much sharper angles of branching prevailed (modal value 5°, arithmetic mean 15°). The mean internode-to-internode angle on continuing rhizomes was about 8°, with a wide variation. An architectural, spatially-explicit model ofPhragmites rhizome growth has been developed, showing that thePhragmites population in the studied locality can be maintained by vegetative multiplication, and seedling recruitment is not needed for its long-term persistence.