Judit Mádl-Szőnyi

Basin-scale conceptual groundwater flow model for an unconfined and confined thick carbonate region

Application of the gravity-driven regional groundwater flow (GDRGF) concept to the hydrogeologically complex thick carbonate system of the Transdanubian Range (TR), Hungary, is justified based on the principle of hydraulic continuity. The GDRGF concept informs about basin hydraulics and groundwater as a geologic agent. It became obvious that the effect of heterogeneity and anisotropy on the flow pattern could be derived from hydraulic reactions of the aquifer system. The topography and heat as driving forces were examined by numerical simulations of flow and heat transport. Evaluation of groups of springs, in terms of related discharge phenomena and regional chloride distribution, reveals the dominance of topography-driven flow when considering flow and related chemical and temperature patterns. Moreover, heat accumulation beneath the confined part of the system also influences these patterns. The presence of cold, lukewarm and thermal springs and related wetlands, creeks, mineral precipitates, and epigenic and hypogenic caves validates the existence of GDRGF in the system. Vice versa, groups of springs reflect rock–water interaction and advective heat transport and inform about basin hydraulics. Based on these findings, a generalized conceptual GDRGF model is proposed for an unconfined and confined carbonate region. An interface was revealed close to the margin of the unconfined and confined carbonates, determined by the GDRGF and freshwater and basinal fluids involved. The application of this model provides a background to interpret manifestations of flowing groundwater in thick carbonates generally, including porosity enlargement and hydrocarbon and heat accumulation.RésuméL’application du concept de modélisation régionale d’écoulements d’eau souterraine contrôlé par la gravité (MRESCG) au système hydrogéologique complexe carbonaté épais de la Chaîne Transdanubienne (CT), Hongrie, est justifiée sur la base du principe de continuité hydraulique. Le concept MRESCG informe sur l’hydraulique du bassin et sur les eaux souterraines en tant qu’agent géologique. Il apparaît clair que l’effet de l’hétérogénéité et de l’anisotropie sur le mode d’écoulement peut être dérivé des réactions hydrauliques du système aquifère. La topographie et la chaleur en tant que forces motrices ont été examinées à l’aide de simulations numériques de l’écoulement et du transport de la chaleur. L’évaluation de groupes de sources, en termes de phénomènes de débits associés et de distribution régionale des chlorures, révèle la prédominance des écoulements associés à la topographie lorsque l’on considère les flux et les modes connexes de distribution de la chimie et des températures. En outre, l’accumulation de la chaleur sous la partie captive du système influence également ces modes de distribution. La présence de sources froides, tièdes et thermales et de zones humides associées, criques, précipités minéraux, et de grottes épigéniques et hypogéniques valide l’existence du MRESCG dans le système. Vice versa, les groupes de sources reflètent l’interaction eau–roche et le transport de chaleur par advection et informent sur l’hydraulique du bassin. A partir de ces résultats, un modèle conceptuel MRESCG généralisé est proposé pour une région carbonatée libre et captive. Une interface a été mise en évidence à proximité de la marge des carbonates libres et captifs, déterminée par le MESRCG, où eau douce et des fluides du bassin sont impliqués. L’application de ce modèle fournit une base pour interpréter les manifestations d’écoulements d’eau souterraine dans des carbonates épais, comprenant généralement l’élargissement de la porosité et l’accumulation d’hydrocarbure et de chaleur.ResumenLa aplicación del concepto de flujo subterráneo regional forzado por gravedad (GDRGF) a los sistemas de potentes carbonatos potentes hidrogeológicamente complejos de las Transdanubian Range (TR), Hungría, se justifica basado en el principio de continuidad hidráulica. El concepto de GDRGF informa acerca del agua subterránea y de la hidráulica de la cuenca como un agente geológico. Es evidente que el efecto de la heterogeneidad y la anisotropía en el modelo de flujo podría ser derivada de las reacciones hidráulicas del sistema acuífero. Se examinaron la topografía y el calor como forzantes mediante simulaciones numéricas de flujo y de transporte de calor. La evaluación de los grupos de manantiales, en términos relacionados a fenómenos de descarga y la distribución de cloruro regional, revela el predominio de la forzante del flujo por la topografía al considerar los flujos y los patrones químicos y de temperatura relacionados. Por otra parte, la acumulación de calor debajo de la parte confinada del sistema también influye en estos patrones. La presencia de manantiales fríos, templados y calientes y los humedales relacionados, arroyos, precipitados de minerales, y las cuevas epigénicas y hipogénicas verifica la existencia del sistema GDRGF. Viceversa, los grupos de manantiales reflejan la interacción roca–agua y el transporte de calor advectivo e informa sobre el sistema hidráulico de la cuenca. Basado en estos resultados, se propone un modelo conceptual GDRGF generalizado para una región de carbonatos no confinada y confinada. Una interfaz se reveló cerca del margen de los carbonatos no confinados y confinadas, determinada por el GDRGF y por el agua dulce y los fluidos de la cuenca en cuestión. La aplicación de este modelo proporciona generalmente un antecedente para interpretar las manifestaciones del flujo del agua subterránea en carbonatos potentes, incluyendo la ampliación de la porosidad y la acumulación de hidrocarburos y de calor.摘要根据水力连续性原则,对重力驱使区域地下水流概念在匈牙利Transdanubian山脉水文地质条件复杂的厚层碳酸盐系统的应用进行了调整。重力驱使区域地下水流概念就是将流域水力学和地下水作为一个地质营力。很明显,不均匀性各向异性对水流模式的影响来自于含水层系统的水力反应。通过水流和热量传输数值模拟对作为驱动力的地形和热量进行了调查。群泉相关的排泄现象和区域氯化物分布评价揭示,鉴于水流和相关的化学和温度模式,地形驱动水流占主导优势。此外,系统承压部分之下的热量积累也影响这些模式。冷泉、微温泉和热泉的出现以及相关湿地、溪流、矿物沉淀物和外成、深成洞穴的出现确认系统中存在着重力驱使区域地下水流。反过来也是如此,泉群反映了岩-水相互作用和平流热量传输,揭示了流域水力学。根据这些发现,提出了非承压和承压碳酸盐地区概化重力驱使区域地下水流概念模型。揭示了非承压和承压碳酸盐边缘附近的界面,这个界面是由重力驱使区域地下水流、淡水和所涉及到的流域流体确定的。这个模型的应用通常提供了解译这个厚层碳酸盐地层中出现流动地下水,包括孔隙度扩大及碳氢化合物和热量积累的背景。ResumoA modelagem do sistema carbonácio espesso e hidrogeologicamente complexo da Região da Transdanúbia (RT), na Hungria é realizada por meio da aplicação do conceito do escoamento regional de água subterrânea por gravidade (ERASG), com base no princípio da continuidade hídrica. O conceito ERASG está relacionado com a hidráulica da bacia levando-se em conta as águas subterrâneas como um forçante geológica. Obtiveram-se evidências de que o efeito da heterogeneidade e anisotropia sobre o padrão de escoamento é determinado a partir de respostas hidráulicas do sistema aquífero. O trabalho analisou o comportamento da topografia e do calor como forçantes por meio de simulações numéricas de escoamento e transporte de calor. A avaliação de grupos de fontes, em termos de fenômenos de descarga e distribuição de cloreto, revelou a predominância de forças gravitacionais no escoamento ao considerar conjuntamente ao escoamento a distribuição de constituintes e o padrão de temperaturas. De modo específico, observou-se que o calor acumulado na porção confinada do aquífero influencia tais padrões. A presença de fontes de diferentes temperaturas (frias, mornas e quentes) e corpos de água conectados a este sistema, como pântanos, riachos, precipitações minerais e cavernas epigênicas e hipogênicas validam a existência de ERASG no sistema. Por outro lado, grupos de fontes refletem a interação água–rocha e o transporte advectivo de calor e evidenciam sobre a hidráulica da bacia. Com base nestas evidências, o trabalho propõe um modelo conceitual ERASG generalizado para uma região carbonácia livres e confinadas. Próximo à margem dos carbonatos livres e confinados foi encontrada uma interface determinada pelo ERASG, a água superficial e os fluidos basais presentes. A aplicação do modelo produz um arcabouço de conhecimento suficiente para interpretar de maneira geral fenômenos de escoamento subterrâneo em carbonatos espessos, incluindo-se porosidades variáveis e acumulação de hidrocarbonetos e calor.

Biofilm Bacterial Communities Inhabiting the Cave Walls of the Buda Thermal Karst System, Hungary

The diversity of biofilm bacterial communities associated with cave walls of the Buda Thermal Karst System (BTKS) located in Hungary was studied by scanning electron microscopy and molecular cloning based on 16S rRNA genes. Samples from two sites, the Molnár János cave (MJB) and the Rudas-Török spring cave (RTB), respectively, were analyzed and compared. The presence of iron precipitates was typical at both study sites, despite the fact that the cell morphological structure of the biofilms observed by SEM was characteristically different. Clones analyzed from BTKS were found to belong to 10 common phyla (Thermodesulfobacteria, Chloroflexi, Nitrospirae, Chlorobi, Proteobacteria, Firmicutes, Actinobacteria, Planctomycetes, Bacteroidetes, Verrucomicrobia) within the domain Bacteria. Moreover, sequences related to Aquificeae, Acidobacteria and Gemmatimonadetes were exclusive to MJB, while Cyanobacteria were found in RTB only. The phylogenetic distribution of the dominant bacterial clones was quite dissimilar between the two sites. In the biofilm from MJB clones affiliated with Firmicutes, whereas in the RTB clones related to Deltaproteobacteria were found in the highest number. In addition, substantially larger numbers of clone sequences related to thermophilic bacteria were recovered from MJB. On the basis of sequences of known microorganisms corresponding to our clone sequences, it is assumed that aerobic as well as anaerobic iron and sulfur transformation performed by different bacterial communities might be important biogenic processes in both caves.

Hazards in Karst and Managing Water Resources Quality

Karst is an extremely fragile natural environment. The geological, morphological, hydrological, and hydrogeological features of karst determine an overall high vulnerability to a number of potentially dangerous events. The delicate equilibrium of karst ecosystems can be dramatically and irreversibly changed, as a consequence of both natural and anthropogenic impacts. This contribution examines the main peculiarity of karst and discusses the main natural and anthropogenic hazards affecting karst. Sinkholes, mass movements, floods, and loss of karst landscape are dealt with and discussed also by means of description of some case studies. Actions to mitigate the hazard in karst are also treated, highlighting the necessity to protect karst, an environment that needs specific regulations to be properly safeguarded. In particular, the Karst Disturbance Index, to evaluate the degree of disturbance done by man to the natural karst, is discussed. Groundwater contamination is by the World Health Organization listed among the world’s severest problems. Globally, water resources are limited and under pressure from urbanization and climate change. Among available drinking water resources, groundwater from karst aquifers is progressively becoming more valuable for potable, irrigation, and other agricultural and industrial use due to its abundance (high flow rate springs up to some tens of m3/s) and relatively high quality of water. However, its efficient use and protection poses a great challenge to urban karstology due to the very high susceptibility to contamination. The concept of groundwater vulnerability and contamination risk assessment is presented as an alternative approach for source protection zoning and land-use planning in karst. Specifically, vulnerability assessment has in some countries already been adopted by some national water-related policies as it confirmed to be a practical tool for protection zoning. It offers balance between groundwater protection and economic interests. The resulting maps are useful for planners and developers dealing with the protection and management of karst groundwater. However, caution needs to be taken when selecting the appropriate method for vulnerability assessment and when interpreting the results. Karst groundwater protection mostly relies on the implementation of sanitary protection zones where different restrictions apply. A review of the relevant legislation of several European countries showed that the groundwater travel time is the most frequent criterion for the delineation of sanitary protection zones, where the horizontal travel time to the groundwater source is generally considered. As a result, some countries increasingly use groundwater vulnerability maps to define sanitary protection zones and to implement more stringent measures where groundwater is vulnerable. A step further in the optimization of the sanitary protection zone delineation approach is to include the travel time through the vadose zone and to take into account surface water flow to the ponor. The total travel time (ttot) is calculated to obtain the travel time from any point in the catchment area to the tapping structure. For the ponor catchment area, ttot is the sum of the surface water travel time to the ponor (ts) and the travel time from the ponor to the tapping structure, based on dye-tracing tests. For any point outside the catchment area of the ponor, the total travel time is the sum of the vertical (t v) and horizontal (t h) groundwater travel times. Apart from test results obtained using natural and artificial dye tracers, the vertical travel time can be estimated based on vulnerability assessment, while the horizontal time can be assessed by analyzing spring hydrographs. The vulnerability map produced on the basis of total travel time calculations can easily be converted into a map of sanitary protection zones, depending on national legislation. The Remediation of Groundwater in Karst section describes aggressive technologies currently being applied to remediate karst aquifers, including in situ thermal treatment, in situ chemical oxidation, in situ bioremediation, and pump and treat. The fundamentals of each technology are discussed, including design principles, failure mechanisms, and amenable contaminants. The authors first provide an overview of trends in the groundwater remediation industry, which is followed by thought-provoking discussion on the politics of remediation in karst. Special attention is given to the technical challenges presented by karst, such as conduit flow and dissolution features, which may make remediation impracticable. On the technical side, this chapter includes a demonstration of modeling tools to assist with remedial evaluation and design. For example, the authors illustrate the use of VS2DTI for heat transport modeling in thermal remediation design, and the conduit flow process (CFP) for pump and treat design. Each example illustrates the need to incorporate conduit geometry and flow in the remedial analysis, as the use of equivalent porous media (EPM) techniques would lead to poor remedial performance. The hydrogeology of the thick karstified carbonate regions is challenging not only theoretically but also from a practical point of view. In these systems different types of groundwater flow are operating on distinct timescales associated with different types of permeability. Practical and scientific concerns related to karst hydrogeology are often on a regional scale such as sustainable water management, contamination of aquifers, and geothermal utilization. It is key issue to understand the regional and hydraulically connected nature of carbonate systems and to find appropriate solution for these particular problems. The importance of the gravity-driven flow concept is that it helps to understand the common genesis of thermal flow. The paper presents a deduced generalized flow pattern for deep carbonate regions which can provide a basis for finding similarities between thermal springs connected to continental carbonates. The understanding of the scale effect is highlighted to resolve practical problems. An important consequence of the hydraulic continuity and relatively higher hydraulic diffusivity of karst is that the effects of natural or artificial stresses on the groundwater level can propagate greater distances and depths than in siliciclastic sedimentary basins. The Transdanubian Range, Hungary can give an “in situ example” for the operation of hydraulic continuity based on a “long-term pumping test.” The fact of hydraulic continuity operating on a different scale can be used also during the planning of geothermal doublet systems and in the necessity of the use of heat content of effluent lukewarm and thermal springs and wastewater of spas in discharge zones of thermal water. Inadequate management of transboundary aquifers can lead to various groundwater quality (changes in groundwater flow, levels, volumes) and quantity (dissolved substances) problems. These problems are more difficult to prevent, mitigate, and solve in an international context than in the case of national aquifers. International cooperation is necessary to ensure an appropriate assessment, monitoring, and management of transboundary groundwater resources. International agreements are made to prevent potential conflicts and to improve the overall benefit from groundwater. In practice, agreements, to be made and respected, require a sufficient knowledge on the resource, its current state, and the trends. This is often a challenge for invisible groundwater and especially in a complex hydrogeological environment like karst. Aquifers in karst are very vulnerable as well, asking for an additional attention of national and international water authorities. This chapter describes DIKTAS, a case study of transboundary aquifers in the Dinaric karst region; it addresses motivation for international water cooperation, methodological approach, achieved results, and current efforts.

Diversity and morphological structure of bacterial communities inhabiting the Diana-Hygieia Thermal Spring (Budapest, Hungary)

The Buda Thermal Karst System is an active hypogenic karst area that offers possibility for the analysis of biogenic cave formation. The aim of the present study was to gain information about morphological structure and genetic diversity of bacterial communities inhabiting the Diana-Hygieia Thermal Spring (DHTS). Using scanning electron microscopy, metal accumulating and unusual reticulated filaments were detected in large numbers in the DHTS biofilm samples. The phyla Actinobacteria, Firmicutes and Proteobacteria were represented by both bacterial strains and molecular clones but phyla Acidobacteria, Chlorobi, Chlorofexi, Gemmatimonadetes, Nitrospirae and Thermotogae only by molecular clones which showed the highest similarity to uncultured clone sequences originating from different environmental sources. The biofilm bacterial community proved to be somewhat more diverse than that of the water sample and the distribution of the dominant bacterial clones was different between biofilm and water samples. The majority of biofilm clones was affiliated with Deltaproteobacteria and Nitrospirae while the largest group of water clones was related to Betaproteobacteria. Considering the metabolic properties of known species related to the strains and molecular clones from DHTS, it can be assumed that these bacterial communities may participate in the local sulphur and iron cycles, and contribute to biogenic cave formation.

State of the art of karst vulnerability assessment: overview, evaluation and outlook

The study gives an overview of the evolution of the concepts and approaches to karst groundwater vulnerability, its connections to previous vulnerability evaluations and of the steps proposed for the assessment. The majority of the methods are based on prerequisites derived from the basic processes of shallow karst systems in the form of transferred parameters. A systematic survey of existing methods and their applications highlights the significance of scale, parameters, its intrinsic or specific and source or resource nature. Revealing the relationships between methods helps to understand their innovations, advantages, disadvantages and the data need. Based on the literature study, the critical examination of the physical reliability of the resulting vulnerability maps and the necessity of their validation is also highlighted. The paper considers the possible and desirable directions for further research, including the development of process-based methods and involvement of an understanding of the flow and transport processes of karstified carbonates. However, the various aspects of water management are not discussed in the present study.

Hydraulic evaluation of the hypogenic karst area in Budapest (Hungary)

The Buda Thermal Karst area, in central Hungary, is in the focus of research interest because of its thermal water resources and the on-going hypogenic karstification processes at the boundary of unconfined and confined carbonates. Understanding of the discharge phenomena and the karstification processes requires clarification of the groundwater flow conditions in the area. Accordingly, the aim of the present study was to present a hydraulic evaluation of the flow systems based on analyses of the archival measured hydraulic data of wells. Pressure vs. elevation profiles, tomographic fluid-potential maps and hydraulic cross sections were constructed, based on the data distribution. As a result, gravitational flow systems, hydraulic continuity, and the modifying effects of aquitard units and faults were identified in the karst area. The location of natural discharge areas could be explained and the hydraulic behavior of the Northeastern Margin Fault of the Buda Hills could be determined. The flow pattern determines the differences in the discharge distribution (one- and two-component) and related cave-forming processes between the Central System (Rózsadomb area) and Southern System (Gellért Hill area) natural discharge areas. Among the premises of hypogenic karstification, regional upward flow conditions were confirmed along the main discharge zone of the River Danube.RésuméL e de l’intérêt de la recherche à cause de ses ressources en eau thermale et des processus de karstification hypogénique en cours à la limite des carbonates libres et captifs. La compréhension des phénomènes de décharge et des procédés de karstification nécessite une clarification des conditions d’écoulement des eaux souterraines dans la zone. Le but de la présente étude était ainsi de présenter une évaluation hydraulique des systèmes d’écoulement basée sur les analyses des données hydrauliques mesurées sur des puits disponibles dans les archives. Des profils de pression en fonction de l’altitude, des cartes d’imagerie du potentiel de fluide et des coupes transversales hydrauliques ont été élaborés à partir de la distribution spatiale des données. En conséquence, les systèmes d’écoulement gravitaire, la continuité hydraulique, et les effets modificateurs des unités aquitards et des failles ont été identifiés dans la région karstique. La localisation des zones de décharge naturelle pourrait être expliquée et le comportement hydraulique de la faille de la marge nord-est. des collines de Buda pourrait être déterminé. Le mode d’écoulement détermine les différences dans la distribution de la décharge (à une ou deux composantes) et les processus de formation des cavités entre les zones de décharge naturelle du Système Central (région de Rózsadomb) et le Système du Sud (zone des collines de Gellért). Parmi les hypothèses relatives à la karstification hypogénique, les conditions d’écoulement régional ascensionnel ont été confirmées le long de la zone de principale décharge du Danube.ResumenLa zona de Buda Thermal Karst, en el centro de Hungría, está en el foco de interés de la investigación debido a sus recursos de agua termal y los procesos de karstificación hipogénica en curso en el límite de carbonatos confinados y no confinados. La comprensión de los fenómenos de descarga y de los procesos de karstificación requiere aclarar las condiciones de flujo de agua subterránea en la zona. En consecuencia, el objetivo del presente estudio fue presentar una evaluación hidráulica de los sistemas de flujo basados en el análisis de los datos hidráulicos de archivos en pozos. Se construyeron perfiles de presión vs elevación, mapas tomográficos de fluido potencial y secciones transversales hidráulicas, basados en la distribución de datos. Como resultado se identificaron los sistemas de flujo gravitatorio, la continuidad hidráulica y los efectos modificadores de las unidades de acuitardas y de las fallas en el área kárstica. La ubicación de las áreas de descarga natural podría ser explicada y el comportamiento hidráulico de la falla de Margen Noreste de las Colinas de Buda podría ser determinado. El esquema de flujo determina las diferencias en la distribución de la descarga (uno y dos componentes) y los procesos de formación de cuevas relacionados entre las áreas de descarga natural del Sistema Central (área de Rózsadomb) y del Sistema Sur (área de Gellért Hill). Entre las premisas de karstificación hipogénica, se confirmaron las condiciones regionales de flujo ascendente a lo largo de la zona de descarga principal del río Danubio.摘要匈牙利中部的布达热岩溶地区由于其热水资源及非承压和承压碳酸盐边界持续的深成岩溶化过程而成为研究兴趣的焦点。了解补给现象和岩溶化过程需要弄清楚本地区地下水流状况。因此,目前的研究目的就是根据井过去档案记载的水力资料对水流系统的水力状况进行评估。基于资料的分布,绘制了压力对高程的剖面、层析成像液体-潜力图和水力横断面。因此,确认了岩溶区的重力水流系统、水力连续性及弱透水层单元和断层的改性效果。天然补给区的位置可以解释,布达山东北边缘断层的水力特性可以确定。水流模式决定了中部系统(Rózsadomb地区)和南部系统(Gellért山地区)天然排泄区之间排泄分布(一个和两个组分)和相关的洞穴形成过程方面的差异。在存在着深成岩溶化前提下,确定了沿多瑙河主要排泄带的区域向上水流条件。Tartalmi kivonatA Budai Termálkarszt Magyarország középső régiójában, fedett és fedetlen karbonátos kőzetek határzónájában húzódik. Termálvíz készletének, valamint a határzónában zajló hipogén karsztosodási folyamatoknak köszönhetően, intenzíven kutatott terület. A megcsapolódási jelenségek és a karsztosodási folyamatok megértéséhez a terület felszínalatti áramlási rendszereinek vizsgálata szükséges. Jelen tanulmány célja az áramlási rendszerek hidraulikai feldolgozása archív kútadatok alapján. A munka során az adateloszlás figyelembevételével nyomás-eleváció profilok, tomografikus folyadék-potenciál térképek és hidraulikai keresztszelvények készültek. Az alkalmazott módszerek eredményeként gravitáció által vezérelt áramlási rendszerek és a hidraulikus folytonosság jelenléte, valamint a vízfogó képződmények és vetők áramlást módosító hatása került kimutatásra a területen. Sikerült meghatározni továbbá a természetes megcsapolódási területek elhelyezkedésének okát, valamint a Budai-hegység Északkeleti peremvetőjének hidraulikai szerepét is. A kimutatott áramlási mintázat meghatározza a megcsapolódási területek (egy- illetve két-komponensű) jellegét és az ehhez kapcsolódó barlangképződési folyamatokat a Rózsadombi és Gellért-hegyi területeken. Végül, a Duna menti megcsapolódási zónában bizonyítást nyert a hipogén karsztosodás egyik elengedhetetlen feltétele, a regionális feláramlás.ResumoA área Buda Thermal Karst, na região central da Hungria, está em foco quanto ao interesse de pesquisa devido aos seus recursos hídricos hidrotermais e aos processos de carstificação hipogênica atualmente em curso no limite entre carbonatos confinados e não confinados. A compreensão dos processos de carstificação e do fenômeno de descarga exige o esclarecimento das condições de fluxo das águas subterrâneas da área. Consequentemente, o objetivo do presente estudo foi apresentar uma avaliação hidráulica dos sistemas de fluxo com base nos registros de dados hidráulicos de poços. Foram desenhados perfis de pressão vs. elevação, mapas tomográficos de potencial de fluido e seções transversais hidráulicas, baseados na distribuição de dados. Como resultados foram identificados sistemas de fluxo gravitacional, continuidade hidráulica, e o efeito modificador de falhas e de unidades aquitardes do carste da área. A localização das áreas de descarga natural pôde ser explicada e o comportamento hidráulico no Northeastern Margin Fault do Buda Hills pôde ser determinado. O padrão de fluxo determina as diferenças na distribuição da descarga (um e dois componentes) e a formação relacionada de cavernas entre o Sistema Central (área de Rózsadomb) e o Sistema Sul (área de Gellért Hill). Dentre as premissas da carstificação hipogênica, as condições regionais de fluxo ascendente ao longo da área de descarga do Rio Danúbio foram confirmadas.

Deinococcus budaensis sp. nov., a mesophilic species isolated from a biofilm sample of a hydrothermal spring cave

Following the exposure of a biofilm sample from a hydrothermal spring cave (Gellért Hill, Budapest, Hungary) to gamma radiation, a strain designated FeSTC15-38T was isolated and studied by polyphasic taxonomic methods. The spherical-shaped cells stained Gram-negative, and were aerobic and non-motile. The pH range for growth was pH 6.0-9.0, with an optimum at pH 7.0. The temperature range for growth was 20-37 °C, with an optimum at 28 °C. Phylogenetic analysis based on the 16S rRNA gene sequence of the isolate indicated that the organism belongs to the genus Deinococcus. The highest sequence similarities appeared with Deinococcus hopiensis KR-140T (94.1 %), Deinococcus aquaticus PB314T (93.3 %) and Deinococcus aerophilus 5516T-11T (92.7 %). The DNA G+C content of the novel strain was 68.2 mol%. The predominant fatty acids (>10 %) were iso-C16 : 0 and C16 : 1ω7c, and the cell-wall peptidoglycan type was A3β l-Orn-Gly2-3, corroborating the assignment of the strain to the genus Deinococcus. Strain FeSTC15-38T contained MK-8 as the major menaquinone and several unidentified phospholipids, glycolipids and phosphoglycolipids. Resistance to gamma radiation (D10) of strain FeSTC15-38T was <3.0 kGy. According to phenotypic and genotypic data, strain FeSTC15-38T represents a novel species for which the name Deinococcus budaensis sp. nov. is proposed. The type strain is FeSTC15-38T (=NCAIM B.02630T=DSM 101791T).

Fluid Flow Systems and Hypogene Karst of the Transdanubian Range, Hungary—With Special Emphasis on Buda Thermal Karst

Carbonate regions have great economic importance for water supply, oil and gas reservoirs, geothermal fluids and also Mississippi Valley-type ore deposits. Therefore, the understanding and consequences of flow pattern in carbonates require special interest. The hypogene and epigene karst areas of carbonate sequences were distinguished and associated with different orders of groundwater flow. However, the effect of confinement on flow pattern of carbonate aquifers was not fully considered in previous studies. We demonstrated the most important prerequisites and consequences of the application of the gravity-driven regional groundwater flow concept for carbonate sequences at different degrees of confinement. The results put into a frame the distribution of different springs and caves (epigene and hypogene) of the carbonate system of the Transdanubian Range, Hungary, and provide insights for better understanding of the hydrogeology of areas with similar unconfined and confined settings. Relationship among different flow regimes, distribution and character of springs and hypogene karstification processes, in addition to natural discharge-related phenomena, such as mineral and microbial precipitates, were recognized in the area of Buda Thermal Karst. This area is a natural laboratory where the connection between groundwater flow and karstification processes can be studied.

Potential maps for the hydrogeologic prerequisites of the installation of deep geothermal doublets and groundwater source heat pump systems in Budapest, Hungary

Budapest is famous for its thermal springs and spas and outstanding thermal water resources. In the 21st century renewable energy utilization — including the use of geothermal energy — became the focus of interest. Improving the use of the different forms of geothermal energy requires the assessment of their possibilities. The potential for deep geothermal doublet systems for direct heating in Budapest was evaluated based on the temperature conditions, the depth and reconnaissance of the carbonate reservoir. NW Buda is not appropriate for thermal water exploration. SW and SE Budapest have better temperature conditions but the lithology of the reservoir is uncertain. Beneath Pest the thermal water is well exploitable. It is obvious from the map of the region that the area is promising; however, due to the hydraulic continuity of the system, reinjection is desirable. Considering the reliability of the employed data the geothermal potential map is suitable only for general orientation and guidance. The geoth...

Radionuclides in the waters of the Bükk region, Hungary

The aim of the present study is to characterize the distribution of the 238U decay series radionuclides, focusing on uranium, radium, in the cold, lukewarm and thermal karst waters in the Bükk region. This is a novel approach to characterize fluids and understand their mixing in regional discharge zones of carbonate aquifers. Based on the measurements, simple flow system, without mixing, is supposed, and the elevated radium content might be connected to hydrocarbon reservoir fluids. The results may support the improvement of protection strategies of springs and wells involved in water supply.