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Příbram, Czech Republic

Kozubikova-Balcarova E.,Charles University | Beran L.,Agency for Nature Conservation and Landscape Protection of the Czech Republic | Duris Z.,University of Ostrava | Fischer D.,Mining Museum Pribram | And 3 more authors.
Ethology Ecology and Evolution | Year: 2014

The crayfish plague pathogen (Aphanomyces astaci) is one of the most important threats to indigenous European crayfish. Although it belongs among the most studied pathogens of invertebrates, only a few recent studies are available on the epidemiology of crayfish plague and its long-term effects on crayfish populations. We provide detailed data on 11 populations of European crayfish (Astacus astacus, A. leptodactylus, Austropotamobius torrentium) hit by crayfish plague in the Czech Republic between 1998 and 2011. We repeatedly surveyed the affected localities in the years following the disease outbreaks to investigate potential recovery of crayfish populations and to search for the likely sources of infection. Although the mortalities severely decimated all studied populations, European crayfish could be found in the watercourse catchments after the disease outbreaks in all but two cases. In five cases, migration barriers apparently supported crayfish survival; in two cases, the disease stopped spreading even without the presence of any barrier. Indigenous crayfish were recorded directly in the affected parts of five studied streams after some time but in most cases populations have not yet reached the original densities. Their recovery seems influenced by the population size in unaffected refuges as well as time since the outbreak. Sources of infection and transmission pathways of A. astaci apparently vary in the Czech Republic. Aphanomyces astaci of three genotype groups originating in different crayfish plague pathogen carriers were involved in the outbreaks. Direct transmission of A. astaci from invasive American crayfish present in the same stream is likely in three cases; however, these host crayfish were not recorded at the remaining localities, and long-range dispersal or other pathogen sources may be assumed. We hypothesize that chronic A. astaci infections leading to disease outbreaks under specific conditions may occur in some populations of indigenous crayfish in the Czech Republic. © 2014 Dipartimento di Biologia, Università di Firenze, Italia. Source

PlaSIl J.,ASCR Institute of Physics Prague | Kasatkin A.V.,V O Almazjuvelirexport | SKoda R.,Masaryk University | Skacha P.,Mining Museum Pribram | Skacha P.,Charles University
Mineralogical Magazine | Year: 2014

Klajite, MnCu4(AsO4)2(AsO3OH)2(H2O)10, the Mn-Cu-bearing member of the lindackerite group, was found in Jáchymov, Czech Republic, as the second world occurrence. It is associated with ondrus?ite and other arsenate minerals growing on the quartz gangue with disseminated primary sulfides, namely tennantite and chalcopyrite. Electron-microprobe data showed klajite aggregates to be chemically inhomogeneous at larger scales, varying from Mn-Ca-rich to Cu-rich domains. The chemical composition of the the Mn-rich parts of aggregates can be expressed by the empirical formula (Mn0 . 4 6Ca0 . 2 2Cu0 . 07Mg0 . 0 2 )S 0 . 7 7(Cu3 . 8 2Mg0 . 1 4Ca0 . 0 3Zn0 . 0 1 ) S4 . 00(As1 . 94Si0 . 06)S 2 . 0 0 O8[AsO2.73(OH)1.27]2(H 2O)10 (mean of seven representative spots; calculated on the basis of As + Si + P = 4 a.p.f.u. (atoms per formula unit) and 10 H2O from ideal stoichiometry), showing a slight cationic deficiency at the key Me-site. According to single-crystal X-ray diffraction, klajite from Jáchymov is triclinic, P1- , with a = 6.4298(8), b = 7.9716(8), c = 10.707(2) Å , a = 85.737(12)°, b = 80.994(13)°, g = 84.982(10)°, and V = 538.85(14) Å 3, Z = 1. The crystal structure was refined to R1 = 0.0628 for 1034 unique observed reflections (with Iobs > 3s(I)), confirming that klajite (Mn-Cu member) and ondrus?ite (Ca-Cu member) are isostructural. The current data-set allowed determination of the positions of several hydrogen atoms. Discussion on hydrogen bonding networks in the structure of klajite as well as detailed bond-valence analysis are provided. © 2014 The Mineralogical Society. Source

Plasil J.,ASCR Institute of Physics Prague | Veselovsky F.,Czech Geological Survey | Hlousek J.,U Rohacovych kasaren 24 | Skoda R.,Masaryk University | And 5 more authors.
American Mineralogist | Year: 2014

Mathesiusite, K5(UO2)4(SO4) 4(VO5)(H2O)4, a new uranyl vanadate-sulfate mineral from Jáchymov, Western Bohemia, Czech Republic, occurs on fractures of gangue associated with adolfpateraite, schoepite, čejkaite, zippeite, gypsum, and a new unnamed K-UO2-SO 4 mineral. It is a secondary mineral formed during post-mining processes. Mathesiusite is tetragonal, space group P4/n, with the unit-cell dimensions a = 14.9704(10), c = 6.8170(5) Å, V = 1527.78(18) Å3, and Z = 2. Acicular aggregates of mathesiusite consist of prismatic crystals up to ∼200 μm long and several micrometers thick. It is yellowish green with a greenish white streak and vitreous luster. The Mohs hardness is ∼2. Mathesiusite is brittle with an uneven fracture and perfect cleavage on {110} and weaker on {001}. The calculated density based on the empirical formula is 4.02 g/cm3. Mathesiusite is colorless in fragments, uniaxial (-), with ω = 1.634(3) and ε = 1.597(3). Electron microprobe analyses (average of 7) provided: K2O 12.42, SO 3 18.04, V2O5 4.30, UO3 61.46, H2O 3.90 (structure), total 100.12 (all in wt%). The empirical formula (based on 33 O atoms pfu) is: K4.87(U0.99O 2)4(S1.04O4)4(V 0.87O5)(H2O)4. The eight strongest powder X-ray diffraction lines are [dobs in Å (hkl) I rel]: 10.64 (110) 76, 7.486 (200) 9, 6.856 (001) 100, 6.237 (101) 85, 4.742 (310) 37, 3.749 (400) 27, 3.296 (401) 9, and 2.9409 (510) 17. The crystal structure of mathesiusite was solved from single-crystal X-ray diffraction data and refined to R1 = 0.0520 for 795 reflections with I > 3σ(I). It contains topologically unique heteropolyhedral sheets based on [(UO2)4(SO4)4(VO5)] 5-clusters. These clusters arise from linkages between corner-sharing quartets of uranyl pentagonal bipyramids, which define a square-shaped void at the center that is occupied by V5+ cations. Each pair of uranyl pentagonal bipyramids shares two vertices of SO4 tetrahedra. Each SO4 shares a third vertex with another cluster to form the sheets. The K+ cations are located between the sheets, together with a single H2O group. The corrugated sheets are stacked perpendicular to c. These heteropolyhedral sheets are similar to those in the structures of synthetic uranyl chromates. Raman spectral data are presented confirming the presence of UO2 2+, SO4, and molecular H 2O. Source

Svobodova J.,T. G. Masaryk Water Research Institute | Douda K.,T. G. Masaryk Water Research Institute | Stambergova M.,Agency for Nature Conservation and Landscape Protection of the Czech Republic | Picek J.,T. G. Masaryk Water Research Institute | And 2 more authors.
Aquatic Conservation: Marine and Freshwater Ecosystems | Year: 2012

Although the noble crayfish (Astacus astacus L.) and stone crayfish (Austropotamobius torrentium Schr.) are critically endangered European species, their water quality requirements are not sufficiently known. This study aimed to investigate the physico-chemical tolerance range of the noble and stone crayfish in the Czech Republic compared with those of the invasive spiny-cheek crayfish (Orconectes limosus Raf.). At 1008 sites with crayfish either absent or present, the following 18 physico-chemical variables were investigated: dissolved oxygen, pH, BOD5, CODCr, ammonia, ammonium ions, nitrite, nitrate ions, zinc, copper, iron, aluminium, calcium, sulphates, chlorides, total phosphorus, suspended solids, and conductivity. For the noble and stone crayfish, only minor differences in water quality were found. This indicates that the water quality requirements of these indigenous crayfish are likely to be very similar. However, significant differences in water quality were observed between locations inhabited by indigenous crayfish and those inhabited by the invasive spiny-cheek crayfish. Based on these findings, we hypothesize that the invasive species is able to survive in locations with lower water quality. Simple logistic regression models were then used to examine relationships between the presence or absence of noble crayfish and each evaluated water quality variable. The presence of this species was related significantly with those variables that indicate nutrient enrichment (particularly ammonium, BOD5, and nitrite) and to iron. Overall, although the indigenous crayfish species were found at several sampling sites that had impaired water quality, the statistical analyses indicate that the indigenous species require water of high quality. Improvement in water quality is therefore an important step in sustaining indigenous crayfish populations. © 2012 John Wiley & Sons, Ltd. Source

Vlach P.,University of West Bohemia | Svobodova J.,T. G. Masaryk Water Research Institute | Fischer D.,Mining Museum Pribram
Knowledge and Management of Aquatic Ecosystems | Year: 2012

The stone crayfish (Austropotamobius torrentium Schrank) is one of the two native crayfish species in the Czech Republic. The populations as well as physical and chemical parameters of water (pH, conductivity, dissolved oxygen, undissolved particles, NH3, NH4 +, NO 2 -, NO3 -, phosphorus, Ca 2+ and SO4 2 -) of 33 streams were examined to find the ecological plasticity of this crayfish and some relations between these parameters and population densities. The mentioned parameters often significantly varied at the sites. Two approaches were applied to find relations between these parameters and observed abundance. At first, the observed streams were compared using RDA (streams × physical-chemical parameters). No significance was found while testing relationship between the streams grouped along the 1st axis of model and the observed abundances of stone crayfish. However, some correlations between abundance and conductivity, calcium, nitrates and sulphates were found using polynomial regression. These relationships are explicable in terms of mutual correlations, underlying geology and other factors which affect abundances. In conclusion, A. torrentium is able to inhabit waters with a large range of physical and chemical parameters of the water without any fundamental influence on population densities. Water properties play an indisputable role as limiting ecological factors at uncommon concentrations, but population densities are probably influenced much more by the types of habitats, habitat features, predation and other ecological factors. © ONEMA, 2013. Source

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