Spring Runoffs Research Articles

Assessment of Water Resources under Climate Change in Western Hindukush Region: A Case Study of the Upper Kabul River Basin

This study aims to estimate the surface runoff and examine the impact of climate change on water resources in the Upper Kabul River Basin (UKRB). A hydrological model was developed using the Soil and Water Assessment Tool (SWAT) from 2009 to 2019. The monthly calibration was conducted on streamflow in six stations for the period from 2010 to 2016, and the results were validated from 2017 to 2018 based on available observed data. The hydrological sensitivity parameters were further prioritized using SWAT-CUP. The uncertainty of the model was analyzed by the 95% Prediction Uncertainty (95PPU). Future projections were analyzed for the 2040s (2030–2049) and 2090s (2080–2099) compared to the baseline period (1986–2005) under two representation concentration pathways (RCP4.5, RCP8.5). Four Regional Climate Models (RCMs) were bias-corrected using the linear scaling bias correction method. The modeling results exhibited a very reasonable fit between the estimated and observed runoff in different stations, with NS values ranging from 0.54 to 0.91 in the calibration period. The future mean annual surface runoff exhibited an increase in the 2040s and 2090s compared to the baseline under both RCPs of 4.5 and 8.5 due to an increase in annual precipitation. The annual precipitation is projected to increase by 5% in the 2040s, 1% in the 2090s under RCP4.5, and by 9% in the 2040s and 2% in the 2090s under RCP8.5. The future temperature is also projected to increase and consequently lead to earlier snowmelt, resulting in a shift in the seasonal runoff peak to earlier months in the UKRB. However, the shifts in the timing of runoff could lead to significant impacts on water availability and exacerbate the water stress in this region, decreasing in summer runoff and increasing in the winter and spring runoffs. The future annual evapotranspiration is projected to increase under both scenarios; however, decreases in annual snowfall, snowmelt, sublimation, and groundwater recharge are predicted in the UKRB.

Impact of alteration corridors on karst reservoir organisation and evolution of groundwater flow path: An example from the southern border of the Larzac Causse, southern France

All the features of karstic reservoirs result from the chemical and/or mechanical erosion of an initial rock volume, which modifies the initial petrophysical properties (i.e., porosity and permeability). The spatial distribution and organisation of the karst system in a carbonate massif are often overlooked in studies on karst hydrological functioning. However, these parameters are key to understand and accurately model dynamic flow. This contribution aims at characterising the nature and impact of alteration corridors on the organisation and evolution of the karstic reservoir and its present-day functioning. We focus on characterising the specific impact of the late onset of pocket valley regressive erosion on the organisation of the present-day drainage system. We used a 3D approach to correlate field observations on the surface and in caves, with remote sensing. The expression of alteration corridors is analysed in a 40 km2 area on the southern border of the Larzac Causse. This Jurassic carbonate massif is affected over its entire thickness by a network of vertically elongated alteration corridors containing dissolution-collapse breccia, mainly oriented in a N-S direction. Ghost-rock karstification played a significant part in the karstic reservoir structure and evolution. Alteration corridors result from the in-situ dissolution of the bedrock along an initial jointing pattern. The dissolution-collapse breccia corridors correspond to ghost-rock corridors selectively emptied of their alterite, under the effect of a hydraulic gradient. The vertically elongated structure of alteration corridors that cross-cut the Jurassic sequence enables fluid circulation from an upper to a lower aquifer, which were initially separated by a Toarcian marly seal unit. The subsequent initiation of pocket valleys led to the rapid evacuation of the residual alterite contained in ghost-rock corridors, under the influence of gravity. These alteration corridors determine the position of present-day pocket valley springs and enhance the regressive erosion dynamics, that progressively capture a north-east flowing watershed (Vis River). Finally, residual alterites are evacuated below the overflow spring altitude during high-flow events by flooding/dewatering of galleries. Such mechanisms of alterite evacuation provide insight into i) the part of the karstic reservoir that is connected to the spring, and ii) the dynamics of the associated flows. This study suggests that corridor networks constitute a substantial volume of porous and permeable materials that plays a major role in the present-day groundwater flow path. Such features should be considered valuable drilling targets for water exploration when located below the piezometric level.

Capturing Seismic Signals From Karst Aquifer Injection Experiments and a Natural Recharge Event

AbstractVariations in subsurface flow processes through a karst aquifer that feeds Bear Spring in southeastern Minnesota were captured on a temporary seismic network during injection experiments and a natural recharge event. Each experiment involved injecting ∼13,000 L of water into an overflow spring, and the natural event was triggered by a large rainstorm of ∼70 min in duration. During the injection experiments, the largest amplitude signals in the ground velocity seismograms occurred as the water first fell onto the rock at the overflow spring and as the large slug of water reached a sump or water‐filled passage. During the natural rainstorm event, the overflow spring began flowing and total spring discharge (perennial emanation points and the overflow spring) increased from ∼100 to 300 L/s. Seismic signals during and following the rain event include broadband noise from raindrops impacting the ground, as well as large amplitude signals while water levels rose; the latter occurred over a 5‐s period, producing multiple pulses of ground motion up to ∼0.5 mm/s. Based on seismic array analysis, high frequency signals during the natural recharge event and one of the injection experiments are largely sourced from south of the array, where a sump exists and the conduit orientation changes, but additional modeling is required to further understand which of a set of possible mechanisms is mostly likely the cause of these seismic signals.

Multi-approach characterization of groundwater for irrigated agriculture in southwest Burkina Faso

This study aims at contributing to the sustainable management of groundwater emergences located in the Sindou Peaks irrigated area. The choice of this study area is due, on the one hand, to its geological context located between the sedimentary and crystalline rocks and, on the other hand to its economic interest. The study focused on understanding the groundwater emergences mechanism and their origin which are currently poorly known. To this end, geophysical investigations such as very low frequency electromagnetic (VLF) and self-potential surveys were carried out. The electromagnetic survey provided a 2D image of the subsoil conductivity and highlighted the fault zones. Self-potential surveys confirmed the effectiveness of groundwater emergence through the fault zone shown by the electromagnetic surveys. These geophysical investigations, coupled with geologic, hydrogeologic (piezometric map), and geomorphologic (3D digital elevation) data have enabled the explanation of the groundwater emergence conditions. Furthermore, the hydrochemical study is conducted by collecting and analyzing the groundwater emergences sample in dry season 2020. The physical characteristics and hydrochemical facies using the piper diagram, and Chebotarev evolution sequence were used to determine the origin of the groundwater. The results showed three different types of springs. The Hillslope springs formed on the very rugged slopes of Sindou peaks, whose water comes from rain. The overflow springs or Mound Form, resulting from the emergence, through fractured zones of Kawara Sindou Sandstone, of groundwater at the interface of the sedimentary and crystalline rocks. Finally, the depression springs appear at the outlet of the perimeter and result from the intersection between the groundwater water table and natural ground.

Nontargeted Identification of an N-Heterocyclic Compound in Source Water and Wastewater as a Precursor of Multiple Nitrosamines.

N-Nitrosamine disinfection byproducts (DBPs) are a health concern because they are probable human carcinogens. Complex organic nitrogenous compounds, nitrosamine precursors, are largely unidentified in source water. Using stable isotopic labeling-enhanced nontargeted analysis, we identified a natural product N-heterocyclic amine 1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid (MTCCA) in source water. Interestingly, we discovered that chloramination of MTCCA-containing water could produce four nitrosamines: methylethylnitrosamine, N-nitrosopyrrolidine, N-nitrosoanatabine, and N-nitrosoanabasine. Computational modeling and experimental results helped explain potential pathways of nitrosamines generated from chloramination of MTCCA. Further investigations confirmed widespread occurrence of MTCCA in source water and wastewater. Its concentration ranged from high in upstream creeks (23.2-332.2 ng L-1) to low in the river (5.7-37.6 ng L-1) during the 2020 spring runoffs, indicating that sources of MTCCA came from creeks around farms. Analysis of wastewater before and after ultraviolet, as well as microfiltration with subsequent ozonation treatments, showed increased MTCCA after treatments, demonstrating a difficulty to degrade and remove MTCCA in water. This study discovered the extensive presence of MTCCA in source water and wastewater, suggesting that natural N-heterocyclic compounds may serve as a new source of nitrosamine precursors.

Diagnosis of the Availability of Groundwater Resources for Off-season Irrigation on the Pic of Sindou Rice Perimeter in Burkina Faso

In Burkina Faso, more precisely, in the Cascades region, on the Pic of Sindou rice perimeter, producers made dike to channel water from overflow springs for off-season irrigation. However, this perimeter like most of the developed areas in the country is subject to the scarcity of water resources to carry out off-season activities. The objective of this study was therefore to analyze the problem of water on the Pic of Sindou rice perimeter in order to propose solutions to overcome the lack of water. The estimation of the volume of water taken from the aquifer, through the springs for off-season irrigation was made using the volumetric method and surveys of 200 producers on their method of managing irrigation during February-July 2019. Gross irrigation water requirements were determined using climatic data from the Karfiguela station. And, the method of the water table fluctuation from 2016 to 2019 is used to estimate the variation of the groundwater stock. Gross irrigation water requirements are currently satisfied at 8.3%, hence the inability of the four springs to cover production on the 260 hectare developed. The diagnosis also revealed that approximately 20% of the volume of water transported in the channels evaporates or infiltrates into the soil; 15% of spring water is not channeled and 18% is lost during off hours. However, the analysis of the variation of the groundwater stock revealed the existence of a groundwater reserve which can be mobilized by catchment works to satisfy the water deficit currently on the perimeter and even cover the extension of the perimeter to 300 hectare of available area.

Investigating karst aquifers in tectonically complex alpine areas coupling geological and hydrogeological methods

In this work, a reliable understanding of the storage patterns and flow dynamics of a tectonically complex karst system is attained by means of the combined analysis of results derived from geological and karst-specific -i.e. hydrogeological- approaches (hydrodynamic, hydrochemical, hydrothermal and isotopic). The pilot site comprises rocks belonging to six different complexes within the Betic Cordillera: External Zone (1), Flysch Complex (1) and the Internal Zone (4). Quick and sharp variations in natural responses after rainfall were recorded in the overflow springs located in the External Zone. In contrast, groundwater drained by permanent springs placed in the Internal Zone present high mineralization and temperature values, as well as lagged and buffered responses to precipitation events. At a first glance, one could assume that two independent systems with different behaviors are at work, following a classical interpretation: conduit flow-type functioning for Jurassic limestones (External Zone) and diffuse-flow behavior for the Triassic calcareous rocks (Internal Zone). However, integration of results with those derived from the water budget and geological observations leads us to propose a sole aquifer, formed by rocks belonging to several geological domains, but hydrogeologically connected, where shorter and longer water–rock interactions along flow paths coexist. Overthrust surfaces and the subsequent normal faults involve diverse low permeable formations imbricated within a tectonic suture, inducing strong heterogeneities in groundwater flow patterns. The geological complexity and the inner geometry at the southeast border of the aquifer jointly modulate the global signal coming from the External Zone, which is attenuated before arriving at the permanent springs found in the Internal Zone. We conclude by emphasizing that a continuous transfer of feedback from geological to hydrogeological approaches, and vice versa, enhances knowledge in both directions, helping us to avoid misinterpretations about the hydrogeological behaviors of aquifers and, ultimately, to better evaluate and manage water resources.

Hydrogeology of a weathered fractured aquifer system near Gitega, Burundi

The domestic water supply of Burundi is mainly based on some 25,000 springs that provide water through gravity systems. These systems have their natural limitation and cannot respond to future domestic water needs caused by the enormous annual population growth. An estimate of the quantity and quality of groundwater resources in the crystalline and metamorphic hard-rock environment, with strongly variable weathering features, is a prerequisite to ensure future water supply from groundwater resources. The hydrogeology of the Nyanzari aquifer system, which is used for the water supply of the city of Gitega in central Burundi, has been investigated with the aim of understanding aquifer characteristics. Results indicate that weathering of the metamorphic basement rocks has led to the development of two-staged aquifers: a deeper fractured aquifer in the saprock, covered by a shallow saprolite aquifer. This shallow aquifer is fed directly by precipitation and discharges at numerous small overflow springs along the valley edges. In general, the discharge of the springs shows seasonal variation patterns with maxima shortly after the rainy season similar to those of the hydraulic heads measured in the saprock aquifer. Groundwater management in the Nyanzari wellfield is partly unsustainable since abstraction is temporarily higher than recharge, even if, so far, periods of over-abstraction have been compensated by later rainy seasons. The lessons learned concerning the behaviour of the strongly weathered fractured aquifer system in Nyanzari will help to develop and manage comparable groundwater resources in Burundi.

Carbon dioxide and dissolution rate dynamics within a karst underflow-overflow system, Savoy Experimental Watershed, Arkansas, USA

Within numerical models of karst development, geochemical and hydrological boundary conditions are typically assumed to be constant. However, rates of calcite dissolution in natural karst systems can vary substantially in time. In particular, variation in carbon dioxide (CO2) concentrations has been shown to produce time variability in dissolution rates in karst streams, but controls on CO2 variation within karst systems are relatively poorly quantified. Here we analyze hourly in-situ measurements of dissolved CO2, discharge, and specific conductance at a pair of karst underflow-overflow springs and examine potential drivers of variability in CO2 and dissolution rates. The springs display strong seasonal variability in CO2 and saturation state as well as moderate variation during storm events. Though both springs have elevated CO2 concentrations in the summer season, the overflow spring experiences a substantial decrease in dissolved CO2 below a critical discharge threshold. We hypothesize that this decrease results from ventilation within the overflow portion of the system as segments of the flow path transition from full pipe to open channel flow. The overflow spring experiences substantially lower average dissolution rates than the underflow spring, despite larger discharge and chemical variability during high flow events at the overflow spring. Though open systems are frequently presumed to have higher dissolution rates, because of their ability to replenish CO2 that is consumed in the dissolution process, these data suggest that dissolution rates within the closed portion of the system may in some cases be higher due to the inability of closed flow paths to ventilate excess CO2 to the atmosphere. Such conditions are likely to occur in conduits where CO2 concentrations are elevated above atmospheric levels and average flow through times are short compared to the time scale over which water reaches equilibrium with respect to calcite.

Laminated tufa sediments formed from overflow karst springs: Controls on their deposition and carbon–oxygen isotope records

AbstractTufa sediments are freshwater carbonates that precipitate in karst regions after degassing of carbon dioxide from groundwater in contact with the atmosphere. When laminated, these carbonates can provide high‐resolution records for the study of climate, hydrological and environmental conditions at the time of their precipitation. The formation of these carbonates directly depends on the hydrological regime, and in karst regions discontinuous discharges are often recorded. This study investigates the record of recent laminated tufa sediments precipitated downstream overflow springs in Trabaque Canyon (central Spain). The hydrological dynamics of the karst system were monitored for over three years and a stable isotope record was obtained from laminated tufa carbonates precipitated from an overflow spring. Additionally, a hydrological model of overflow springs was generated and a tufa δ18O record under constrained parameters was simulated. Temperature is the dominant control of the variation in tufa δ13C and δ18O values within each lamina, although when comparing different laminae, δ13CDIC and δ18O of river water are also major controls. The positive correlation between tufa δ13C values and water temperature is caused by the fractionation occurred by carbon dioxide degassing due to the thermal dependence of carbon dioxide solubility. Additionally, the system recorded a temperature‐independent degassing process caused by the large gradient between groundwater and atmospheric carbon dioxide that is limited to the proximity of the spring. This study cautions on the risk of assuming continuous deposition when studying laminated tufa sediments and highlights the potential of their stable isotope records to provide hydrological information of their aquifers during the past.

Modeling spatially and temporally varied hydraulic behavior of a folded karst system with dominant conduit drainage at catchment scale, Hochifen–Gottesacker, Alps

Summary Karst aquifers are important for freshwater supply, but difficult to manage, due to highly variable water levels and spring discharge rates. Conduits are crucial for groundwater flow in karst aquifers, but their location is often unknown, thus limiting the applicability and validity of numerical models. We have applied a conduit model (SWMM) to simulate highly variable flow in a folded alpine karst aquifer system, where the underground drainage pattern is comparatively well-known from previous tracer studies. The conduit model was coupled with a reservoir model representing recharge, storage and transfer of water in the epikarst and unsaturated zone. The global optimization approach (GA) was applied to achieve an efficient model calibration. It was possible to simultaneously simulate the highly variable discharge characteristics of an estavelle, and overflow spring and a permanent spring draining the conduit system. The model allowed for the collection of spatially differentiated information on recharge, rapid flow and slow flow in four individual sub-catchments. The formation of backwater upgradient from conduit restrictions turned out to be a key process in activating overflow springs. The proposed modeling approach appears to be transferrable to other karst systems with predominant conduit drainage, but requires previous knowledge of the configuration of the conduit system.

Using non-conservative tracers to characterise karstification processes in the Merinos-Colorado-Carrasco carbonate aquifer system (southern Spain)

The systematic sampling of the chemical composition of the groundwater from five karst springs (including an overflow spring) and one outflowing borehole have permitted to determine distinctive chemical changes in the waters that reflect the geochemical processes occurring in a carbonate aquifer system from southern Spain. The analysis of the dissolution parameters revealed that geochemical evolution of the karst waters basically depends on the availability of the minerals forming aquifer rocks and the residence time within the aquifers. In the three proposed scenarios in the aquifers, which include the preferential flow routines, the more important geochemical processes taking place during the groundwater flow from the recharge to the discharge zones are: CO2 dissolution and exsolution (outgassing), calcite net dissolution, calcite and dolomite sequential dissolution, gypsum/anhydrite and halite dissolution, de-dolomitization and calcite precipita- tion. A detailed analysis of the hydrochemical data set, saturation indices of the minerals and partial pressure of CO2 in the waters joined to the application of geochemical modelling methods allowed the elaboration of a hydro- geochemical model of the studied aquifers. The developed approach contributes to a better understanding of the karstification processes and the hydrogeological functioning of carbonate aquifers, the latter being a crucial aspect for the suitable management of the water resources.

Recharge area delineations and hazard and vulnerability mapping in Perry County, Missouri

Eight recharge areas have been delineated in the sinkhole plain of Perry County, MO, USA. The groundwater systems delineated were the Moore Cave system, Keyhole Spring, Ball Mill Spring, the Crevice Cave system, the Mystery Cave system, the Rimstone River Cave system, Thunderhole Resurgence, and Running Bull Cave. These systems include four of the five longest caves known in Missouri and two of the top four in having the most globally rare species. The delineations were done in support of the grotto sculpin (Cottus specus) which is a fish adapting to cave environments, and because these cave streams seem to be the source of impairment in their receiving streams. Seventeen springs, including overflow springs, are associated with these groundwater systems. The results of a total of 87 dye introductions were used to complete the delineations, and the sampling network included 93 sampling stations. The tracing showed that the Mystery Cave system overflows to several springs under high flow conditions. Almost 94 km2 of land were included in the delineations. Hazards and vulnerability were also mapped. All of the recharge areas have potentially ineffective private septic systems, agriculture without universal application of best management practices, roads with poor water quality runoff and the threat of spills, and sinkhole dumps. The Crevice Cave system recharge area also has the City of Perryville, numerous underground storage tanks, and several facilities with national pollutant discharge elimination system (NPDES) permits, and hazardous waste generators, making it the least likely system to be a practical target for conservation. All of the recharge areas were mapped as highly vulnerable due to the rapid recharge of groundwater through discrete karst features. The data generated from this investigation can be used to direct efforts to conserve the grotto sculpin and improve water quality in the cave streams and in their receiving streams.

Cecembia calidifontis sp. nov., isolated from a hot spring runoff, and emended description of the genus Cecembia

Two red-pigmented isolates, designated RQ-33(T) and TU-13, were recovered from hot spring runoffs on the Island of São Miguel in the Azores, Portugal. These organisms have an optimum growth temperature of approximately 45 °C and an optimum pH for growth between 7.5 and 8.5. Based on 16S rRNA gene sequence analysis, the novel isolates were most closely related to the type strain of Cecembia lonarensis at 96.4 % pairwise similarity. Cells of the two isolates were non-motile, rod-shaped, Gram-stain-negative, strictly aerobic, and oxidase- and catalase-positive. The major fatty acids were iso-C15 : 0 and C15 : 0, phosphatidylethanolamine was the major polar lipid, and menaquinone 7 was the major respiratory quinone. Based on phylogenetic analyses, and physiological and biochemical characteristics, these isolates from the Azores represent a novel species of the genus Cecembia for which the name Cecembia calidifontis is proposed with strain RQ-33(T) ( = DSM 21411(T) = LMG 24596(T)) as the type strain. The description of the genus Cecembia is also emended.

Functioning of a karst aquifer from S Spain under highly variable climate conditions, deduced from hydrochemical records

Over a period of three hydrological years during which precipitation was highly variable, measurements of discharge, electrical conductivity, temperature and chemical components of the water at the Canamero spring (southern Spain) were taken in order to characterise the hydrogeological functioning of the karst aquifer that it drains. The results obtained from analysis of the frequency distribution of electrical conductivity data revealed histograms with a plurimodal morphology (up to 5 modes) and a range of variation that increased with greater pluviometry during the study period. The discharge from this spring increased sharply a few days after major rainfall episodes and, when the discharge reached a value of approximately 3.73 m3/s, an overflow spring started to function. During high-water periods, there were sudden and large falls in EC, temperature and all the chemical components dissolved in the water. This high variability reflects the predominance of groundwater flow through karst drains, a typical feature of conduit flow systems. The considerable hydrochemical heterogeneity observed is caused by the mobilisation of important volumes of recharge waters from shallow areas of the aquifer (soil, epikarst) towards the discharge point, with greater participation of the unsaturated zone during high-water conditions, and a more active role played by the saturated zone during low-water conditions. In karst systems such as the one drained by the Canamero spring, it is important to monitor several responses (hydrodynamic, hydrothermal, hydrochemical, etc.), with an appropriate sampling frequency and under different hydrometeorological conditions, in order to achieve an adequate hydrological characterisation. This is fundamental for planning, management and protection of groundwater in karst aquifers.

A comparison study on distributed hydrological modelling of a subarctic wetland system

Wetlands occupy 14% of the Canadian territory and mainly exist as bogs, fens, swamps, marshes, and shallow water. Recently, arctic and subarctic wetlands have attracted much attention due to their unique hydrological characteristics, and vulnerability to climate condition changes. To gain insight of the interactions between hydrology and atmosphere of the second largest wetland in Canada - the Hudson Bay Lowlands (HBL), extensive field investigations were conducted from 2006 to 2008 in the Deer River watershed near Churchill, Manitoba, Canada. Hydrologic and geographic conditions, such as frost table, soil moisture and temperature, and streamflow were monitored to advance the understanding of the wetland systems. Following up the field investigation, two semi-distributed hydrological models, Semi-distributed Land Use-based Runoff Processes (SLURP) and WATFLOOD, were employed to simulate the water cycle in the Deer River watershed. They were further compared from the aspects of modelling structures, formulations, parameters, and simulation results. Regardless the distinct simulation concepts (i.e., aggregated simulation area in SLURP and group response unit in WATFLOOD), the results indicated that snowmelt and peaks of spring runoffs simulated by SLURP were earlier than those simulated by WATFLOOD. This may be explained by the exponentially increasing snowmelt rate adopted by SLURP. Lack of considering the existence of permafrost and seasonal ponds in both models tended to underestimate the peaks of spring runoffs. It was also observed that the Morton CRAE method used in SLURP slightly underestimated the summertime evapotranspiration, meanwhile it was overestimated by the Hargreaves Equation employed in WATFLOOD. This study not only helped to fill the knowledge gaps in how well the two widely used models could fit the requirements of subarctic wetlands modelling, but also showed their strength and limitations as well as the potential for improvement.

Hydrologie du Dévoluy : La Souloise, les Gillardes et le puits des Bans

Hydrology of Dévoluy (French PreAlps) : Souloise river, Gillardes springs and puits des Bans Dévoluy is a karstic system in the French Alps with a size of 165 km2. The basin is drained by a surface river, the Souloise, and an underground collector, reappearing at the springs of Gillardes. A cave, the puits (shaft) des Bans, situated 200 m higher, is an overflow spring of the underground system. We studied the discharge of the surface river and the spring as well as the flooding heights in the Puits des Bans during a year. The linear correlation between the spring discharge at Gillardes and the water elevation in the puits des Bans is surprising for a karstic flow. We propose a hydrologie model of two basins with a narrow link and laminar flow, of which the common spring is Gillardes. The obstacle is localised near the important geologic structure named Digne thrust. Some hydrologie properties are developed : hydrologie connections, hydraulic transmissivity, and storage volumes during floods.

Truepera radiovictrix gen. nov., sp. nov., a new radiation resistant species and the proposal of Trueperaceae fam. nov.

Two isolates, belonging to a new species of a novel genus of the Phylum “ Deinococcus/Thermus ”, were recovered from hot spring runoffs on the Island of São Miguel in the Azores. Strains RQ-24 T and TU-8 are the first cultured representatives of a distinct phylogenetic lineage within this phylum. These strains form orange/red colonies, spherical-shaped cells, have an optimum growth temperature of about 50 °C, an optimum pH for growth between about 7.5 and 9.5, and do not grow at pH below 6.5 or above pH 11.2. These organisms grow in complex media without added NaCl, but have a maximum growth rate in media with 1.0% NaCl and grow in media containing up to 6.0% NaCl. The organisms are extremely ionizing radiation resistant; 60% of the cells survive 5.0 kGy. These strains are chemoorganotrophic and aerobic; do not grow in Thermus medium under anaerobic conditions with or without nitrate as electron acceptor and glucose as a source of carbon and energy, but ferment glucose to d-lactate without formation of gas. The organisms assimilate a large variety of sugars, organic acids and amino acids. Fatty acids are predominantly iso- and anteiso-branched; long chain 1,2 diols were also found in low relative proportions; menaquinone 8 (MK-8) is the primary respiratory quinone. Peptidoglycan was not detected. Based on 16S rRNA gene sequence analysis, physiological, biochemical and chemical analysis we describe a new species of one novel genus represented by strain RQ-24 T (CIP 108686 T = LMG 22925 T = DSM 17093 T) for which we propose the name Truepera radiovictrix. We also propose the family Trueperaceae fam. nov. to accommodate this new genus.

Fr

Continuous and orthogonal multiresolution wavelet analyses are applied to rainfall rates and karstic spring runoffs at sites located in the French Pyrenees mountains and the northern Larzac plateau. Compared to classical autocorrelation and spectral analyses, they appear as complementary, while allowing a finer analysis of the signals (sampled at different rates). Several applications are proposed: isolation of time-variable frequency processes (intermittent pumping), characterization of karstification degree and temporal structure of floods.

Bacteria in the Castleton Karst, Derbyshire, England

Abstract The Castleton area contains an extensive and complex karst drainage system. Recharge is provided by allogenic stream sinks and by infiltration into a soil covered autogenic catchment. Concentrations of the sanitary indicator bacteria faecal coliform (FC) were measured weekly over a 84-week period at three stream-sinks (P6, P7 and P8) and at two contrasting springs (Russet Well and Peak Cavern Rising). Russet Well drains the allogenic catchment, but also receives some autogenic recharge whereas Peak Cavern Rising receives only autogenic recharge except at high stage when it functions as an overflow spring for the Russet Well system. Over the year as a whole and during each three-month season, median FC concentrations at P6 were significantly higher than at Russet Well. The difference was greatest during summer/autumn and was lowest in winter/spring and it appears that FC concentrations at the rising are a complex function of faecal inputs and flow through time. The relationship between FC concentrations at Russet Well and at Peak Cavern Rising proved to be complex. Over the sampling period as a whole and during the spring and autumn there was no significant difference between median FC concentrations at the two risings; during the winter, when discharge was highest, median FC concentrations at Russet Well were significantly higher than at Peak Cavern Rising; and during the summer FC concentrations at Peak Cavern Rising were significantly higher than at Russet Well. The high FC concentrations in the sinking streams and at the risings suggest that there could be a health risk to cavers, especially during storm events and the summer. Furthermore, the fact that the waters from both springs contain significant concentrations of FC bacteria indicates that even soil covered karst systems are unable to filter out potentially harmful micro-organisms.