Water Research Institute TGM

Prague, Czech Republic

Water Research Institute TGM

Prague, Czech Republic
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Jirakova H.,University of Bordeaux 1 | Jirakova H.,Charles University | Huneau F.,University of Bordeaux 1 | Hrkal Z.,Charles University | And 3 more authors.
Applied Geochemistry | Year: 2010

The Bohemian Cretaceous Basin represents a complex hydrogeological system composed of several aquifers with very favourable hydrogeological properties. These aquifers have been exploited for many years. The sustainability of such resources might be guaranteed by well organised water management, which requires a detailed knowledge about the functioning of the hydrogeological system. Although many efforts have previously been made to evaluate groundwater residence time, the many intricate geochemical processes complicate groundwater dating. The current study clarifies the functioning of this complex hydrogeological basin using hydrogeochemical and isotopic investigations. Chemical data and a combination of 13C and 14C isotopes within the Cenomanian and the Turonian layers indicate groundwater interactions with deep-seated CO2, rock matrix, surface waters and fossil organic matter. Very depleted δ13C values (average δ13C∼-13.4‰) suggest interactions with fossil organic matter, whereas enriched values account for the interaction with deep CO2 gas ascending from the upper mantle via the numerous faults and fractures, and also, to a lesser extent, from calcite dissolution. Geochemical processes that take place in the system cause a clear depletion in 14C that greatly complicates groundwater residence time evaluation. Different dilution correction models have been applied considering the different C origins. The stable isotope content, mainly 18O values, indicates both the contribution of modern precipitation and the partial infiltration of palaeowaters during colder climatic conditions from the end of the Pleistocene. The apparent 14C groundwater ages range from modern to 11.1ka BP, which suggests some post glacial infiltration from melting ice sheets. Finally, all the acquired information was used to propose a conceptual model of C origin within the basin. © 2010 Elsevier Ltd.

Jirakova H.,University of Bordeaux 1 | Jirakova H.,CNRS Georesources lab | Jirakova H.,Charles University | Huneau F.,University of Bordeaux 1 | And 6 more authors.
Hydrogeology Journal | Year: 2011

Climatic instability during the late Pleistocene has been reflected in the pattern of groundwater recharge. This report summarizes palaeoclimate knowledge during the late Weichselian in Europe. During this period the majority of northern Europe was covered by thick ice sheets and permafrost, preventing aquifers from recharging. In contrast, southern Europe was generally free of these palaeoclimatic features. Palaeoclimatic information has been combined with isotope data to better understand the palaeorecharge conditions and recharge timing across the European continent. The 18O and 2H relationship shows latitudinal plus climatic influences. Radiocarbon data show that while southern European aquifers have generally been recharged continuously during the last 40,000 years, northern European aquifers typically show a recharge gap during the Last Glacial Maximum. Areas that underwent continuous recharge during the entire late Pleistocene period can also be distinguished from areas where recharge to aquifers was prevented during the Last Glacial Maximum. Finally, several examples are presented of melt-water recharge or subglacial recharge. The identification of such diversity in the groundwater palaeorecharge in Europe is of great importance for modellers developing management schemes for groundwater resources. © 2011 Springer-Verlag.

Langhammer J.,Charles University | Hartvich F.,Charles University | Hartvich F.,Czech Institute of Rock Structure And Mechanics | Mattas D.,Czech Technical University | And 2 more authors.
Environmental Monitoring and Assessment | Year: 2012

This paper examines the relationships between watercourse typology and selected indicators of long-term surface water quality for rivers in the Czech Republic. The parameters used to define watercourse typology are in accord with the Water Framework Directive 2000/60/EC outlined by the European Commission. The relationships were tested using descriptive and multivariate statistical analysis, namely cluster analysis and canonical correspondence analysis. It was found that only some of the typological parameters have a close association with indicators of surface water quality. Specifically, the parameters of altitude and geology show clear relationships with pH, calcium content, and the saprobity index of macroinvertebrates. Conversely, parameters that are strongly influenced by anthropogenic pollution show weak relationships with indicators of surface water quality. These depend instead on the presence of pollution sources rather than on natural environmental conditions. © Springer Science+Business Media B.V. 2011.

Hrkal Z.,Water Research Institute TGM | Hrkal Z.,Charles University
NATO Science for Peace and Security Series C: Environmental Security | Year: 2011

The geological view to the issue of impact climate change on water resources on the Earth is the main objective of the paper. The geological excursion into the past of the Earth clearly shows that the climate cannot be stabilized. The volume of water existing on the Earth is stable and has never changed. About 96% of countries have sufficient resources of water. The major reason for water scarcity on the Earth is not unfavorable distribution of natural resources but poverty and lack of education. © Springer Science+Business Media B.V. 2011.

Elgzeli Y.M.,Charles University | Ondovcin T.,Charles University | Hrkal Z.,Charles University | Hrkal Z.,Water Research Institute TGM | And 2 more authors.
Acta Geologica Polonica | Year: 2013

Libya, like many other regions with arid climates, suffers from inadequate water resources to cover all the needs of this rapidly developing country. Increasing amounts of water are needed to supply the population, as well as for agricultural irrigation and industrial use. As groundwater is the main water source in the country, it represents a natural resource of the highest economic and social importance. Conceptual and numerical models were implemented on a regional scale to show how the natural situation has changed following heavy groundwater abstraction during the last decades in the northwestern part of the country. The results of the numerical model indicated that the current zones of depression of the piezometric surface could have been caused by smaller withdrawn amounts than previously estimated. The differences in the assessed withdrawn groundwater volumes seem to be quite high and might have a considerable influence on the future possibilities of groundwater use in the study region.

Jirakova H.,Charles University | Jirakova H.,University of Bordeaux 1 | Jirakova H.,Geomedia Ltd. | Prochazka M.,AQUATEST a.s. | And 6 more authors.
Geothermics | Year: 2011

Groundwater in the Benešov-Ústí aquifer system in the northwestern Bohemian Cretaceous basin has been intensely exploited since the twentieth century. Apart from providing drinking water, it contains the most extensive accumulation of thermal water in the country. However, excessive exploitation can result in temperature declines and changes in the quality of the groundwater in the future. More than a hundred in situ temperature measurements were used to assess the geothermal gradient and heat flux. However, intense groundwater vertical flow across the well significantly controls the heat flux distribution, resulting in a huge range of values-from less than 50mW/m2 within infiltration areas to more than 125mW/m2 in drainage areas. Certain simplifications and corrections considering the vertical flow between different permeable zones were developed, and the correction for topography as well as lithological variability have been applied to improve accuracy of the geothermal gradient assessment. Despite the fact that the Bohemian Cretaceous basin is tectonically very complex, it is concluded that tectonics [with the exception of the Eger (Ohře) rift] has only a secondary effect on the thermal field. Two longitudinal W-E areas in the Benešov-Ústí aquifer system have elevated heat flux values. The calculated heat flux values are useful for heat transfer modelling and the assessment of the sustainable limits of thermal water exploitation. © 2011 Elsevier Ltd.

Reichard M.,Academy of Sciences of the Czech Republic | Vrtilek M.,Academy of Sciences of the Czech Republic | Douda K.,Water Research Institute Tgm | Douda K.,Czech University of Life Sciences | Smith C.,University of St. Andrews
Biology Letters | Year: 2012

The impact of multiple invading species can be magnified owing to mutual facilitation-termed 'invasional meltdown'-but invasive species can also be adversely affected by their interactions with other invaders. Using a unique reciprocal host-parasite relationship between a bitterling fish (Rhodeus amarus) and unionid mussels, we show that an invasive mussel reverses the roles in the relationship. Bitterling lay their eggs into mussel gills, and mussel larvae parasitize fish. Bitterling recently colonized Europe and parasitize all sympatric European mussels, but are unable to use a recently invasive mussel, Anodonta woodiana. The parasitic larvae of A. woodiana successfully develop on R. amarus, whereas larvae of European mussels are rejected by bitterling. This demonstrates that invading species may temporarily benefit from a coevolutionary lag by exploiting evolutionarily naive hosts, but the resulting relaxed selection may facilitate its exploitation by subsequent invading species, leading to unexpected consequences for established interspecific relationships. This journal is © 2012 The Royal Society.

Douda K.,Water Research Institute Tgm | Douda K.,Czech University of Life Sciences | Vrtilek M.,Academy of Sciences of the Czech Republic | Slavik O.,Water Research Institute Tgm | Reichard M.,Academy of Sciences of the Czech Republic
Biological Invasions | Year: 2012

Several freshwater mussel species represent some of the most problematic invasive species and have considerably altered ecosystems worldwide. Their invasion potential has been partially attributed to their free-living larvae, which have a high dispersal capability. We investigated the invasion potential of Anodonta (Sinanodonta) woodiana, a species of East Asian unionid mussel established worldwide despite having an obligatory parasitic stage (glochidium), which must encyst on host fish. The invasion success of A. woodiana has been attributed to the success of worldwide introductions of its sympatric fish hosts. We experimentally found, however, that A. woodiana is a broad host generalist, which can complete its development on all eight fish species tested, both coinvasive and native. Subsequently, we used a data on the occurrence and relative abundance of potential hosts in river habitats in the Czech Republic to project scenarios of the effect of host availability on A. woodiana invasion. We found that host availability does not constitute a major limit for A. woodiana to colonise most aquatic habitats in Central Europe. In addition, we investigated seasonal dynamics of A. woodiana reproduction and did not detect any limitations of its reproduction by ambient water temperatures typical of a Central European lowland river. Consequently, we predict that A. woodiana may further increase the speed and range of its invasion and we discuss possible consequences to native habitats and communities, especially to the endangered species of unionid mussels. © 2011 Springer Science+Business Media B.V.

Douda K.,Water Research Institute TGM | Horky P.,Water Research Institute TGM | Bily M.,Water Research Institute TGM
Animal Conservation | Year: 2012

The conservation of endangered affiliate species, which are critically dependent on the presence of another species, is often hindered by a poor understanding of the relationships between the interacting partners. The parasitic stage of endangered unionid bivalves constitutes a tight host-affiliate linkage between the mussels and their host fishes. However, the threats resulting from potential shortages of the host species are rarely sufficiently quantified and incorporated into conservation strategies. In this paper, we integrated both host quality and availability analyses to assess the potential threats to the endangered thick-shelled river mussel Unio crassus that result from the impairment of its host resources in Central Europe. The experimental determination of the compatibility of U.crassus parasitic larvae (glochidia) with its potential host fishes revealed an intermediate level of host specificity. At least, some glochidia successfully developed on 14 of the 27 potential hosts that were evaluated. Nevertheless, only three fish species (Scardinius erythrophthalmus, Phoxinus phoxinus and Cottus gobio) enabled the majority of the attached glochidia to transform successfully. Subsequently, our analysis of host availability at sites inhabited by living or extirpated populations of U.crassus showed that the local extirpations of U.crassus are likely associated with an impaired status of the fish assemblage and with the absence of the primary host fishes. These results indicate that the availability of host fish resources may have played at least an additive role in the present pan-European decline of U.crassus and that the evaluation of host limitation without precise data on the host compatibility or host abundance may be ineffective for identifying the threats to particular species. It demonstrates a strong need for more thorough incorporation of host limitation issues into conservation strategies for U.crassus and probably also for other species of freshwater mussels that were previously considered safe from host limitation. © 2012 The Zoological Society of London.

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