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Sample records for large karstic spring

  1. Sources of nitrate contamination and age of water in large karstic springs of Florida

    USGS Publications Warehouse

    Katz, B.G.

    2004-01-01

    In response to concerns about the steady increase in nitrate concentrations over the past several decades in many of Florida's first magnitude spring waters (discharge ???2.8 m3/s), multiple isotopic and other chemical tracers were analyzed in water samples from 12 large springs to assess sources and timescales of nitrate contamination. Nitrate-N concentrations in spring waters ranged from 0.50 to 4.2 mg/L, and ??15N values of nitrate in spring waters ranged from 2.6 to 7.9 per mil. Most ??15N values were below 6 per mil indicating that inorganic fertilizers were the dominant source of nitrogen in these waters. Apparent ages of groundwater discharging from springs ranged from 5 to about 35 years, based on multi-tracer analyses (CFC-12, CFC-113, SF6, 3H/3He) and a piston flow assumption; however, apparent tracer ages generally were not concordant. The most reliable spring-water ages appear to be based on tritium and 3He data, because concentrations of CFCs and SF6 in several spring waters were much higher than would be expected from equilibration with modern atmospheric concentrations. Data for all tracers were most consistent with output curves for exponential and binary mixing models that represent mixtures of water in the Upper Floridan aquifer recharged since the early 1960s. Given that groundwater transit times are on the order of decades and are related to the prolonged input of nitrogen from multiple sources to the aquifer, nitrate could persist in groundwater that flows toward springs for several decades due to slow transport of solutes through the aquifer matrix.

  2. Estimating nitrogen loading to ground water and assessing vulnerability to nitrate contamination in a large karstic springs Basin, Florida

    USGS Publications Warehouse

    Katz, B.G.; Sepulveda, A.A.; Verdi, R.J.

    2009-01-01

    A nitrogen (N) mass-balance budget was developed to assess the sources of N affecting increasing ground-water nitrate concentrations in the 960-km 2 karstic Ichetucknee Springs basin. This budget included direct measurements of N species in rainfall, ground water, and spring waters, along with estimates of N loading from fertilizers, septic tanks, animal wastes, and the land application of treated municipal wastewater and residual solids. Based on a range of N leaching estimates, N loads to ground water ranged from 262,000 to 1.3 million kg/year; and were similar to N export from the basin in spring waters (266,000 kg/year) when 80-90% N losses were assumed. Fertilizers applied to cropland, lawns, and pine stands contributed about 51% of the estimated total annual N load to ground water in the basin. Other sources contributed the following percentages of total N load to ground water: animal wastes, 27%; septic tanks, 12%; atmospheric deposition, 8%; and the land application of treated wastewater and biosolids, 2%. Due to below normal rainfall (97.3 cm) during the 12-month rainfall collection period, N inputs from rainfall likely were about 30% lower than estimates for normal annual rainfall (136 cm). Low N-isotope values for six spring waters (??15N-NO3 = 3.3 to 6.3???) and elevated potassium concentrations in ground water and spring waters were consistent with the large N contribution from fertilizers. Given ground-water residence times on the order of decades for spring waters, possible sinks for excess N inputs to the basin include N storage in the unsaturated zone and parts of the aquifer with relatively sluggish ground-water movement and denitrification. A geographical-based model of spatial loading from fertilizers indicated that areas most vulnerable to nitrate contamination were located in closed depressions containing sinkholes and other dissolution features in the southern half of the basin. ?? 2009 American Water Resources Association.

  3. Multifractal modelling of runoffs of karstic springs

    NASA Astrophysics Data System (ADS)

    Márkus, L.

    2003-04-01

    A new multifractal stochastic process, Terdik and Iglói call the Limit of the Integrated Superposition of Diffusion processes with Linear differential Generator (LISDLG) , has been defined for modelling network traffic multifractality. The process is stationary, and exhibits long range dependency or long memory. Its characteristic property is that its bispectrum is real. It serves as the basis of distinction e.g. from the superposition of Levy-processes driven Ornstein-Uhlenbeck processes. Its further appealing property is that its finite dimensional distribution stems from multivariate Gamma, therefore it is inherently positive and skewed (and hence non-Gaussian). All together, this makes it a very promising candidate for modelling e.g. runoff data of springs or river flows. Quite recently Labat et al. (2002, J. of Hydrology, Vol 256, pp.176-195) pointed out multifractal properties of the runoff time series of French karstic springs. We show that runoff data of karstic springs in north-east Hungary possesses multifractal and cumulant-multifractal property as well as long range dependency and fit the above described LISDLG process, to model the phenomenon. Acknowledgement: This research was supported by the Nat. Sci. Research Fund OTKA, grant No.: T 032725.

  4. Groundwater quality impacts from the land application of treated municipal wastewater in a large karstic spring basin: Chemical and microbiological indicators

    USGS Publications Warehouse

    Katz, B.G.; Griffin, Dale W.; Davis, J.H.

    2009-01-01

    Geochemical and microbiological techniques were used to assess water-quality impacts from the land application of treated municipal wastewater in the karstic Wakulla Springs basin in northern Florida. Nitrate-N concentrations have increased from about 0.2 to as high as 1.1??mg/L (milligrams per liter) during the past 30??years in Wakulla Springs, a regional discharge point for groundwater (mean flow about 11.3??m3/s) from the Upper Floridan aquifer (UFA). A major source of nitrate to the UFA is the approximately 64??million L/d (liters per day) of treated municipal wastewater applied at a 774??ha (hectare) sprayfield farming operation. About 260 chemical and microbiological indicators were analyzed in water samples from the sprayfield effluent reservoir, wells upgradient from the sprayfield, and from 21 downgradient wells and springs to assess the movement of contaminants into the UFA. Concentrations of nitrate-N, boron, chloride, were elevated in water samples from the sprayfield effluent reservoir and in monitoring wells at the sprayfield boundary. Mixing of sprayfield effluent water was indicated by a systematic decrease in concentrations of these constituents with distance downgradient from the sprayfield, with about a 10-fold dilution at Wakulla Springs, about 15??km (kilometers) downgradient from the sprayfield. Groundwater with elevated chloride and boron concentrations in wells downgradient from the sprayfield and in Wakulla Springs had similar nitrate isotopic signatures, whereas the nitrate isotopic composition of water from other sites was consistent with inorganic fertilizers or denitrification. The sprayfield operation was highly effective in removing most studied organic wastewater and pharmaceutical compounds and microbial indicators. Carbamazepine (an anti-convulsant drug) was the only pharmaceutical compound detected in groundwater from two sprayfield monitoring wells (1-2??ppt). One other detection of carbamazepine was found in a distant well

  5. Electrical Resistivity Tomography of the Karstic Aquifer of Bittit spring (Middle Atlas, Morocco)

    NASA Astrophysics Data System (ADS)

    Qarqori, Kh.; Rouai, M.; Moreau, F.; Saracco, G.; Hermitte, D.; Boualoul, M.; Dauteuil, O.; Biessy, G.; Sahbi, H.

    2009-04-01

    The Tabular Middle Atlas reservoir is one of the most important aquifers in northern Morocco. It is mainly a water table fractured reservoir consisting of Lias limestone and dolomite. The matrix permeability is very low and water flows essentially along open fractures and karsts. The Bittit Spring belongs to this karstic system and constitutes an important aquifer lying at the junction between the tabular reservoir and the Sais basin. Bittit spring, with an average annual discharge of about 1600 l/s, contributes largely to water supply of the big city of Meknes. Groundwater circulation is complex due to tectonics and to presence of karstic Quaternary travertine overlying Lias carbonate. In Bittit area, travertine is mostly covered by Quaternary basalt. Up to now water flow paths and the underground karst organization remain misknown, and turbidity affects the water quality after rain events. To highlight these issues, an integrated geophysical survey was performed in this area in the framework of a French-Moroccan scientific project. The geophysical imaging was carried out mainly by Electrical Resistivity Tomography (ERT). Resistivity data were acquired by an ABEM Terrameter SAS1000 and a multi-electrode Lund system imaging using a Wenner array configuration of 64 electrodes and 5m spacing, reaching a depth of about 50m. Topographic corrections and 2D inversion models were performed using Res2Dinv software package. Seven 2D resistivity high resolution images have been obtained allowing to detect, delineate important fractures and also to hydrogeological characterization of the underground karst. A borehole of 100m depth was drilled in order to correlate and calibrate geophysical data and proposed models. Two sub-vertical fracture families have been identified with NE-SW and NW-SE directions respectively. These results correlate well with fracture data analysis gathered from remote sensing Spot images at large scale, and from local field fracture scanline surveys. A

  6. Particles in a karstic spring, Swabian Alb: Physicochemical and hydraulic effects during a snow melt event.

    NASA Astrophysics Data System (ADS)

    Schiperski, Ferry; Zirlewagen, Johannes; Hillebrand, Olav; Scheytt, Traugott; Licha, Tobias

    2013-04-01

    The studied karst spring 'Gallusquelle' is located on the Swabian Alb in Southwest Germany. The catchment area of the 'Gallusquelle' measures about 45 km². An average annual discharge of 0.5 m³/s serves drinking water to about 40,000 people via a waterworks. The study is part of the research project 'AGRO' (www.projekt-agro.de). The main objective of the project 'AGRO' is to develop a tool for the process-based risk management of micropollutants and pathogens in rural karst aquifers on catchment scale. As particle related transport could play an important role for micropollutants and pathogens, the characterization of particles in the spring water is one focus of this work. Furthermore we will attempt to correlate physicochemical parameters with the characteristics of particles in the spring water in order to enhance the knowledge of the transport mechanisms within the karst aquifer. For the measurement of the particle concentration and the particle size distribution the CIS 1 (GALAI) was used. The system works in a range of 0.5 to 150 µm with a resolution of at least 0.5 µm. The measurement is based on time-of-transition method using a laser beam. The turbidity was measured with an ULTRATURB PLUS (DR.LANGE) and a Fluorometer (GGUN-FL30, ALBILLIA), both working with scattering light method. To verify these measurements we used a portable turbidimeter (2100P IS PORTABLE TURBIDIMETER, HACH) working with the ratio of the signals from the scattered and the transmitted light. Temperature and electrical conductivity where also measured with the GGUN-FL30, whereby the electrical conductivity was verified with a portable multimeter (HQ 40D, HACH). Discharge, pH, water hardness, anion- and cation concentration, total organic carbon (TOC) and dissolved organic carbon (DOC) were also determined. To characterize the particles, the spring water was filtered onsite and the filter cake was analyzed in the laboratory. For SEM (scanning electron microscopy) including EDAX

  7. Interaction of a fresh water lake and a karstic spring via a syncline fold.

    PubMed

    Rezaei, Abolfazl; Zare, Mohammad; Raeisi, Ezzatollah; Ghanbari, Reza Namdar

    2013-03-01

    Kaftar Lake is a high-altitude fresh water lake located in High Zagros, south of Iran. Despite the high annual evaporation to precipitation ratio in the area, lake water electrical conductivity is usually lower than 1000 µS/cm, this may be due to high seepage from the floor of the lake. Therefore, the hypothesis of possible underground connections between Namdan Basin, where the lake is located, and the surrounding basins with lower elevation (Aspas and Dehbid Basins) was investigated. Hydrogeology, hydrochemistry, and stable isotopes data of the lake and surrounding basins along with the lake water balance study were applied to test the hypothesis. Results indicate that Kaftar Lake has no connection with Aspas Basin in south, but it is hydraulically connected to Dehbid Basin. In Dehbid Basin, "Ghasr_e_Yaghoob spring" (average discharge ≅1200 L/s) emerges from a small outcrop (about 0.8 km(2) ) of Daryan limestone Formation, where this outcrop is much smaller than the required recharge area for such average discharge rate. The study shows that this spring is recharged by Kaftar Lake and Namdan Basin aquifer, through Daryan Formation of Gandboee Syncline located to the northern part of the lake. PMID:22880946

  8. The influence of subaquatic springs in lacustrine sedimentation: Origin and paleoenvironmental significance of homogenites in karstic Lake Banyoles (NE Spain)

    NASA Astrophysics Data System (ADS)

    Morellón, Mario; Anselmetti, Flavio S.; Valero-Garcés, Blas; Giralt, Santiago; Ariztegui, Daniel; Sáez, Alberto; Mata, M. Pilar; Barreiro-Lostres, Fernando; Rico, Mayte; Moreno, Ana

    2014-08-01

    Banyoles (42°08‧N, 2°45‧E) is the largest and deepest lake of karstic-tectonic origin in the Iberian Peninsula. The lake comprises two basins and six sub-circularly shaped sub-basins fed by subaquatic springs. Periods of intense groundwater inflow in the deepest sub-basins lead to the fluidization and re-suspension of previously deposited sediments and subsequent settling forming homogenite deposits on the southern basin intermediate platforms. The multiproxy analysis of sediment cores combined with high resolution seismic stratigraphy (3.5 kHz pinger and multi-frequency Chirp surveys) allows a precise reconstruction of depositional environments and related hydrological variability and groundwater inflow during the last ca. 7.6 cal kyr BP. According to the age model based on 137Cs, 210Pb and AMS 14C dating, homogenite deposition occurred between 7.2 and 5.5 cal kyr BP, stopped during the middle Holocene (5.5-2.8 cal kyr BP) and greatly increased during the last two millennia with a total of 17 homogenite layers individually up to 75 cm-thick. The onset of this unique sedimentation mode at ca. 3 cal kyr BP coincides with an increase in lake level, evidenced by the onlapping of fine-grained, distal sediments over coarser massive, carbonate-rich, littoral deposits. A detailed, multidisciplinary study of the homogenites (sedimentology, physical properties, high-resolution elemental geochemistry, mineral composition, grain-size, organic matter content and SEM) combined with seismic stratigraphy demonstrates that the fluidization events triggering the formation of the homogenites were caused by higher and more intense local groundwater inflow, related to increased rainfall during the Late Holocene and likely intensified by land use changes during the last millennium.

  9. The large karstic holes at the top of the Syrian coastal Mountain Range. Importance of structural setting for the karstogenesis.

    NASA Astrophysics Data System (ADS)

    Mocochain, Ludovic; Blanpied, Christian; Bigot, Jean-Yves; Peyronel, Olivier; Gorini, Christian; Abdalla, Abdelkarim Al; Azki, Fawaz

    2015-04-01

    Along the Eastern Mediterranean Sea, the Syria Coastal Mountain Range spreads from north to south over 150 km of long. This range is a monocline structure stopped by a major escarpment that domines Al-Gahb Graben to the East. The Coastal Mountain Range is mainly formed by Mesozoic limestone that show a major unconformity between the Upper Jurassic and Aptien deposits, and important erosions in the Upper Cretaceous deposits. Locally, the Juro-Cretaceous unconformity is characterized by a layer of continental basalts with fossil woods that reveal a long emersion of the platform. The most recent carbonate deposits at the top of the Coastal Mountain Range are Turonian age. In the center part of the Coastal Mountain Range, in a small area, the Cretaceous carbonates are affected by large karstic dolines. These dolines are curiously located at the top of the mountain range. This position is not beneficial for the development of large karstic holes.

  10. Confronting surface- and groundwater balances on the La Rochefoucauld-Touvre karstic system (Charente, France)

    NASA Astrophysics Data System (ADS)

    Le Moine, Nicolas; AndréAssian, Vazken; Mathevet, Thibault

    2008-03-01

    The Touvre spring is the only outlet of a large karstic system, the La Rochefoucauld karst, located in the West of France. This system is particularly interesting from a modeler's point of view, for it allows to investigate how karstic losses and gains can be accounted for within a rainfall-runoff model. Indeed, this spring is fed by the losses of three rivers, which are themselves gaged after recharging the karstic aquifer: this setting is exceptional in that simulations of surface catchment losses (estimated by the GR4J rainfall-runoff model) can be compared with measurements of spring discharge at the outlet of the karstic system. It provides an opportunity to test the estimates of "catchment leakages", which are often suspected but seldom measurable, against observations. We show here that the conceptualization of surface losses in the GR4J rainfall-runoff model yields simulated leakage volumes that are consistent with the spring flow volumes and that, provided a routing store is added to GR4J to account for the specific retarding behavior of the karstic aquifer, an integrated model can be proposed to represent the behavior of the whole system adequately. The Touvre case study shows that a parsimonious, empirical rainfall-runoff representation of a karstic system is possible. It also provides an independent corroboration for the conceptualization of surface catchment leakages proposed in the GR4J rainfall-runoff model.

  11. Insights into saline intrusion and freshwater resources in coastal karstic aquifers using a lumped Rainfall-Discharge-Salinity model (the Port-Miou brackish spring, SE France)

    NASA Astrophysics Data System (ADS)

    Arfib, Bruno; Charlier, Jean-Baptiste

    2016-09-01

    The aim of this study was to develop a conceptual model of saline intrusion within coastal karst aquifers by analyzing Rainfall-Discharge-Salinity data and to assess freshwater resources using a lumped modeling approach. In a first step, we analyzed 4 years of data (rainfall, discharge and salinity times series) of the Port-Miou brackish submarine spring in South France (400 km2). A conceptual model of the aquifer was then designed to differentiate a deep brackish reservoir and a shallower fresh one. Salinity variations at the spring are assumed to be controlled mainly by dilution originating from the fresh water in the shallower reservoir. In a second step, a lumped modeling approach was developed based on the conceptual model to simulate discharge as well as salinity over time. We proposed a reservoir-model to take into account slow and fast components in the shallower part of the aquifer and a saline intrusion in the deeper one. This Rainfall-Discharge-Salinity model was calibrated and validated for two periods of 1.5 years at a daily time step and was also tested to reproduce a multi-annual evolution of the available discharge and salinity time series. Good simulation results were obtained to reproduce water and mass budgets as well as discharge and salinity dynamics during several hydrological cycles. The simultaneous modeling of hydrodynamics and quality data showed the robustness of the model in addition to its easy implementation. Our results led us to propose a new type of seawater mixing mechanism for brackish springs: the dilution type, in addition to the well-known Ventury suction and Head balance types. The application of the lumped model on the Port-Miou brackish spring validated the hydrogeological processes deduced from experimental data, given an initial quantification of the freshwater resources available in such complex brackish karstic aquifers.

  12. A model of cells as practical approach to simulate spring flow in the Itxina karstic aquifer, Basque Country, Spain.

    PubMed

    Soliz, J G; Acebo, H L

    2001-01-01

    The aim of this study is to apply a parsimonious hydrologic model to the Itxina karstic aquifer that can predict changes in discharge resulting from variable inputs (recharge). The Itxina Aquifer was divided into four cells corresponding to different recharge areas. Each cell was treated as a tank to characterize the conditions within the cell. In the model, when the reservoir boundaries coincide with the position of the siphons, the signal simulated is sensitive to input pulses of the recharge. This supports the hypothesis that the siphons are the controlling mechanism in the flow system of the aquifer. The good agreement between predicted and measured discharges demonstrates the ability of the model to simulate the flow in the Itxina Aquifer. These results demonstrated that the hydraulic conductivity increases downstream within the aquifer. The hydraulic conductivities obtained by calibration varied between 4.2 x 10(-3) m/s upstream of the aquifer, 6.0 x 10(-2) m/s in the central region, and 9.5 x 10(-1) m/s in the lower region of the aquifer. These values seem reasonable because the underground features in the principal caves show that the density of caves increases downstream in the Itxina Aquifer. The simple representation of the system produced results comparable to traditional ground water models with fewer data requirements and calibration parameters. PMID:11340998

  13. Electrical resistivity tomography to characterize a karstic Vauclusian spring: Fontaine d'Orbe (Pyrénées, France)

    NASA Astrophysics Data System (ADS)

    Sirieix, C.; Riss, J.; Rey, F.; Prétou, F.; Lastennet, R.

    2014-06-01

    The study site lies on a karst system in the Pyrénées (France) that crosses the Urgonian limestones. Organic matter was dumped on the west bank of the River Vert d'Arette, which polluted a spring (the Fontaine d'Orbe) situated on the east bank. Electrical resistivity tomography was utilised in order to understand the geometry of this karst outlet. After tests with the pole-pole array, the ideal electrode spacing was found to be less than 3 m. A conduit, a little less than 10 m wide, was discovered, which proved to be the terminal conduit of the karst system. It was established that the conduit traverses both banks of the River Vert d'Arette, thus presenting a hydraulic link between the two sides. Moreover, this conduit, which is totally submerged, passes under the riverbed and goes upwards to the spring. In addition to the geophysical measurements, hydrogeological measurements and observations were made. Based on the characterisation of the geometry of the karst network's terminal conduit, and the fact that is completely full of water and inclined, it is concluded that the Fontaine d'Orbe spring is of the Vauclusian variety.

  14. Modeling daily discharge responses of a large karstic aquifer using soft computing methods: Artificial neural network and neuro-fuzzy

    NASA Astrophysics Data System (ADS)

    Kurtulus, Bedri; Razack, Moumtaz

    2010-02-01

    SummaryThis paper compares two methods for modeling karst aquifers, which are heterogeneous, highly non-linear, and hierarchical systems. There is a clear need to model these systems given the crucial role they play in water supply in many countries. In recent years, the main components of soft computing (fuzzy logic (FL), and Artificial Neural Networks, (ANNs)) have come to prevail in the modeling of complex non-linear systems in different scientific and technologic disciplines. In this study, Artificial Neural Networks and Adaptive Neuro-Fuzzy Interface System (ANFIS) methods were used for the prediction of daily discharge of karstic aquifers and their capability was compared. The approach was applied to 7 years of daily data of La Rochefoucauld karst system in south-western France. In order to predict the karst daily discharges, single-input (rainfall, piezometric level) vs. multiple-input (rainfall and piezometric level) series were used. In addition to these inputs, all models used measured or simulated discharges from the previous days with a specified delay. The models were designed in a Matlab™ environment. An automatic procedure was used to select the best calibrated models. Daily discharge predictions were then performed using the calibrated models. Comparing predicted and observed hydrographs indicates that both models (ANN and ANFIS) provide close predictions of the karst daily discharges. The summary statistics of both series (observed and predicted daily discharges) are comparable. The performance of both models is improved when the number of inputs is increased from one to two. The root mean square error between the observed and predicted series reaches a minimum for two-input models. However, the ANFIS model demonstrates a better performance than the ANN model to predict peak flow. The ANFIS approach demonstrates a better generalization capability and slightly higher performance than the ANN, especially for peak discharges.

  15. Closure of large midline diastema by a "HIV-Spring".

    PubMed

    Harikrishnan, Pandurangan

    2015-01-01

    Midline diastema is a common orthodontic problem in mixed dentition caused by various factors like genetic, supernumery teeth, abnormal frenum attachment, habits and microdontia etc. Large diastemas need closure for the eruption of adjacent teeth. I present here a newly designed customized self active HIV-Spring (Hari Inverted 'V' Spring) for closing a large diastema with minimum orthodontic materials and less activation visits. The spring can be modfied for the three dimensional movement of central incisors. PMID:25881378

  16. Using stable isotopes and multi-spatial variable parameters in characterising the karstic aquifer of the Ajloun area, NW-Jordan - A case study of the Tanour and Rasoun springs

    NASA Astrophysics Data System (ADS)

    Hamdan, Ibraheem; Wiegand, Bettina; Ptak, Thomas; Licha, Tobias; Toll, Mathias; Margane, Armin; Sauter, Martin

    2015-04-01

    Key words: Karst systems, Groundwater vulnerability, Stable isotopes, Jordan. Water resources are extremely scarce in Jordan, which is considered as one of the poorest countries in the world with respect to water resources availability (UNDP 2014), with more than 90% of the country receiving less than 200 mm/year of rainfall (Al Kharadsheh et al. 2012). The most important aquifer for drinking-water purposes in Jordan is the upper Cretaceous limestone aquifer. The karstic springs of Tanour and Rasoun, located in the Ajloun governorate around 75 kilometres northwest of the capital of Amman, have been selected for this study. These springs are the main source for the local domestic water supply, with an average discharge between the years 2000 and 2012 of 200 m3/h and 60 m3/h, respectively (MWI, 2013). During the past few years, the water supply from these two springs had to be discontinued due to high contamination of the groundwater either by microbiological contaminants or by wastewater from local olive oil presses. This wastewater is locally called 'Zeebar'. Understanding of the karst aquifer system, the pathways and movement within the epikarst, and estimation of the travel and residence time within the aquifer is important for managing and evaluating the pollution risk, which affects the usability of groundwater for drinking purposes. For a better understanding of the karstic system and its behaviour, different methods are applied: 1. Analysis of the stable isotope composition of δ2H and δ18O during the winter season for both (a) Tanour and Rasoun groundwater, and (b) rainfall samples collected from several locations at different elevations within the catchment. 2. Analysis of major ion concentrations in groundwater of the Tanour and Rasoun springs. 3. Long-term measurements of different physico-chemical parameters from the Tanour and Rasoun springs (temperature, conductivity, turbidity, TOC, etc.) using multiparameter probes with telemetric data transfer. 4

  17. Using chemical and microbiological indicators to track the impacts from the land application of treated municipal wastewater and other sources on groundwater quality in a karstic springs basin

    NASA Astrophysics Data System (ADS)

    Katz, Brian G.; Griffin, Dale W.

    2008-08-01

    Multiple chemical constituents (nutrients; N, O, H, C stable isotopes; 64 organic wastewater compounds, 16 pharmaceutical compounds) and microbiological indicators were used to assess the impact on groundwater quality from the land application of approximately 9.5 million liters per day of treated municipal sewage effluent to a sprayfield in the 960-km2 Ichetucknee Springs basin, northern Florida. Enriched stable isotope signatures (δ18O and δ2H) were found in water from the effluent reservoir and a sprayfield monitoring well (MW-7) due to evaporation; however, groundwater samples downgradient from the sprayfield have δ18O and δ2H concentrations that represented recharge of meteoric water. Boron and chloride concentrations also were elevated in water from the sprayfield effluent reservoir and MW-7, but concentrations in groundwater decreased substantially with distance downgradient to background levels in the springs (about 12 km) and indicated at least a tenfold dilution factor. Nitrate-nitrogen isotope (δ15N NO3) values above 10 ‰ in most water samples were indicative of organic nitrogen sources except Blue Hole Spring (δ15N NO3 = 4.6 4.9 ‰), which indicated an inorganic source of nitrogen (fertilizers). The detection of low concentrations the insect repellent N, N-diethyl-metatoluamide (DEET), and other organic compounds associated with domestic wastewater in Devil’s Eye Spring indicated that leakage from a nearby septic tank drainfield likely has occurred. Elevated levels of fecal coliforms and enterococci were found in Blue Hole Spring during higher flow conditions, which likely resulted from hydraulic connections to upgradient sinkholes and are consistent with previoius dye-trace studies. Enteroviruses were not detected in the sprayfield effluent reservoir, but were found in low concentrations in water samples from a downgradient well and Blue Hole Spring during high-flow conditions indicating a human wastewater source. The Upper Floridan aquifer

  18. Modeling suspended sediment transport and assessing the impacts of climate change in a karstic Mediterranean watershed.

    PubMed

    Nerantzaki, S D; Giannakis, G V; Efstathiou, D; Nikolaidis, N P; Sibetheros, I Α; Karatzas, G P; Zacharias, I

    2015-12-15

    Mediterranean semi-arid watersheds are characterized by a climate type with long periods of drought and infrequent but high-intensity rainfalls. These factors lead to the formation of temporary flow tributaries which present flashy hydrographs with response times ranging from minutes to hours and high erosion rates with significant sediment transport. Modeling of suspended sediment concentration in such watersheds is of utmost importance due to flash flood phenomena, during which, large quantities of sediments and pollutants are carried downstream. The aim of this study is to develop a modeling framework for suspended sediment transport in a karstic watershed and assess the impact of climate change on flow, soil erosion and sediment transport in a hydrologically complex and intensively managed Mediterranean watershed. The Soil and Water Assessment Tool (SWAT) model was coupled with a karstic flow and suspended sediment model in order to simulate the hydrology and sediment yield of the karstic springs and the whole watershed. Both daily flow data (2005-2014) and monthly sediment concentration data (2011-2014) were used for model calibration. The results showed good agreement between observed and modeled values for both flow and sediment concentration. Flash flood events account for 63-70% of the annual sediment export depending on a wet or dry year. Simulation results for a set of IPCC "A1B" climate change scenarios suggested that major decreases in surface flow (69.6%) and in the flow of the springs (76.5%) take place between the 2010-2049 and 2050-2090 time periods. An assessment of the future ecological flows revealed that the frequency of minimum flow events increases over the years. The trend of surface sediment export during these periods is also decreasing (54.5%) but the difference is not statistically significant due to the variability of the sediment. On the other hand, sediment originating from the springs is not affected significantly by climate change

  19. Karstic Phenomena Susceptibility Map of MÉXICO

    NASA Astrophysics Data System (ADS)

    Espinasa-Pereña, R.

    2013-05-01

    Approximately 20% of the territory of México is underlain by karstifiable rocks, mostly limestones and in lesser proportions gypsum. The majority of these rocks are distributed along the eastern and southern Sierra Madre, the state of Chiapas and the Yucatán peninsula. Differences in geological structure, climate and geomorphic history have resulted in a great variety of karstic landscapes and types of forms. Several important population centers, including large cities with several million inhabitants and numerous smaller towns are built on karstic terrains and obtain their water supplies from karstic aquifers and/or dispose of their waste products on this type of terrain. Severe problems of waste disposal and aquifer contamination have occurred. Additionally, numerous instances of catastrophic collapse and formation of karstic sinkholes have been registered in the Mexican territory, which have affected many communities, roads and other infrastructure, and have even cost several lives. Lack of knowledge of the special characteristics of karstic terrains and their distribution has compounded these problems. As a first approach to these issues, the existing map of Mexican karst (Espinasa-Pereña, 2007) was modified according to the geotechnical classification proposed by Waltham & Fookes (2003). An important consideration taken into account is the difference in speed of development of karstic features depending on lithology, which makes karst developed in gypsum much more hazardous than limestone karst, and also the degree of soil coverage and the types of sinkholes developed on the cover. Also taken in consideration are the differences between karst developed in the Sierra Madre, with rocks highly deformed and fractured, and karst developed on the Yucatán peninsula with almost negligible deformation of the rocks. The resulting map will be useful to Civil Protection authorities as a tool in prognosticating possible affectations due to karstic phenomena. References

  20. Large herbivores surf waves of green-up during spring.

    PubMed

    Merkle, Jerod A; Monteith, Kevin L; Aikens, Ellen O; Hayes, Matthew M; Hersey, Kent R; Middleton, Arthur D; Oates, Brendan A; Sawyer, Hall; Scurlock, Brandon M; Kauffman, Matthew J

    2016-06-29

    The green wave hypothesis (GWH) states that migrating animals should track or 'surf' high-quality forage at the leading edge of spring green-up. To index such high-quality forage, recent work proposed the instantaneous rate of green-up (IRG), i.e. rate of change in the normalized difference vegetation index over time. Despite this important advancement, no study has tested the assumption that herbivores select habitat patches at peak IRG. We evaluated this assumption using step selection functions parametrized with movement data during the green-up period from two populations each of bighorn sheep, mule deer, elk, moose and bison, totalling 463 individuals monitored 1-3 years from 2004 to 2014. Accounting for variables that typically influence habitat selection for each species, we found seven of 10 populations selected patches exhibiting high IRG-supporting the GWH. Nonetheless, large herbivores selected for the leading edge, trailing edge and crest of the IRG wave, indicating that other mechanisms (e.g. ruminant physiology) or measurement error inherent with satellite data affect selection for IRG. Our evaluation indicates that IRG is a useful tool for linking herbivore movement with plant phenology, paving the way for significant advancements in understanding how animals track resource quality that varies both spatially and temporally. PMID:27335416

  1. Stochastic discrete model of karstic networks

    NASA Astrophysics Data System (ADS)

    Jaquet, O.; Siegel, P.; Klubertanz, G.; Benabderrhamane, H.

    Karst aquifers are characterised by an extreme spatial heterogeneity that strongly influences their hydraulic behaviour and the transport of pollutants. These aquifers are particularly vulnerable to contamination because of their highly permeable networks of conduits. A stochastic model is proposed for the simulation of the geometry of karstic networks at a regional scale. The model integrates the relevant physical processes governing the formation of karstic networks. The discrete simulation of karstic networks is performed with a modified lattice-gas cellular automaton for a representative description of the karstic aquifer geometry. Consequently, more reliable modelling results can be obtained for the management and the protection of karst aquifers. The stochastic model was applied jointly with groundwater modelling techniques to a regional karst aquifer in France for the purpose of resolving surface pollution issues.

  2. Confounded winter and spring phenoclimatology on large herbivore ranges

    USGS Publications Warehouse

    Christianson, David; Klaver, Robert W.; Middleton, Arthur; Kauffman, Matthew

    2013-01-01

    Annual variation in winter severity and growing season vegetation dynamics appear to influence the demography of temperate herbivores but parsing winter from spring effects requires independent metrics of environmental conditions specific to each season. We tested for independence in annual variation amongst four common metrics used to describe winter severity and early growing season vegetation dynamics across the entire spatial distribution of elk (Cervus elaphus) in Wyoming from 1989 to 2006. Winter conditions and early growing season dynamics were correlated in a specific way. Winters with snow cover that ended early tended to be followed by early, but slow, rises in the normalized difference vegetation index (NDVI), while long winters with extended periods of snow cover were often followed by late and rapid rises in NDVI. Across the 35 elk ranges, 0.4–86.8 % of the variation in the rate of increase in NDVI’s in spring was explained by the date snow cover disappeared from SNOTEL stations. Because phenoclimatological metrics are correlated across seasons and shifting due to climate change, identifying environmental constraints on herbivore fitness, particularly migratory species, is more difficult than previously recognized.

  3. Large deformation analysis of a dielectric elastomer membrane-spring system

    NASA Astrophysics Data System (ADS)

    He, Tianhu; Cui, Leilei; Chen, Cheng

    2009-07-01

    Due to the capability of large strain, dielectric elastomers are promising for applications as transducers in cameras, robots, valves, pumps, energy harvesters and so on. The dielectric elastomer transducers are based on the deformation of a soft polymer membrane contracting in thickness and expanding in area, which is induced by the application of a voltage across the two compliant electrodes coated on both sides of the membrane. This paper focuses on the large deformation analysis of a dielectric elastomer membrane-spring system. The system is constructed from attaching a disk in the middle of a circular dielectric membrane and then connecting the disk with a spring. This configuration can be potentially used as a key part in valves. The basic governing equations describing the large out-of-plane deformations are formulated, and the obtained equations are solved numerically. The relations related to the displacement of the disk, the spring force, the applied voltage, and the parameters of spring including stiffness and initial length are illustrated. The results show the anticipated displacement of the disk can be controlled by adjusting the parameters of spring and the applied voltage individually or simultaneously, and the parameters of the spring, that is, stiffness and initial length, play an important role in the performance of the membrane-spring system.

  4. Hydrogeological and isotope mapping of the karstic Savica River (NW Slovenia)

    NASA Astrophysics Data System (ADS)

    Brenčič, Mihael; Vreča, Polona

    2015-04-01

    Mapping is important part of the hydrogeological terrain investigations, especially when spatial and temporal relations are not known precisely. There are many different methods available; among them not least important is careful visual inspection of the stream and its stream bed at regular intervals with the aim to detect phenomena which reflect surface water groundwater interactions. In parallel with the inspection various measurements can be performed. Together with usual water electro conductivity and water temperature we tested complimentary information which can be obtained with the concomitant regular sampling for δ18O determination in the river water course. Combination of all these information proved to be very useful in obtaining spatial trends in river characteristics and to determine relations between its water balance components. Testing of the methodology of hydrogeological mapping with the means of isotopes on the karstic Savica River during low flow period where water balance relations between its tributaries were not known before demonstrate the usefulness of the applied approach. Savica River is positioned in the north-west part of Slovenia in the centre of Triglav national Park which covers large part of East Julian Alps. River represents the main recharge of the Bohinj Lake, largest Slovenian natural lake. Savica River is short with the length of only 4.0 km and consists of two tributaries in the upper part; Mala Savica coming from the west and Velika Savica coming from the north-west. The first is recharged from several water caves of various lengths in which water level depends on hydrological conditions, consequently terminal end of the water in its riverbed part changes during the year. The second tributary is recharged from the 510 m long karstic cave with the entrance at 836 m a.s.l. where water disappears over 75 m high famous and picturesque waterfall. Geology of the catchment is predominantly formed by Dachstein limestone of Upper

  5. Hydrogeological and isotope mapping of the karstic Savica River (NW Slovenia)

    NASA Astrophysics Data System (ADS)

    Brenčič, Mihael; Vreča, Polona

    2015-04-01

    Mapping is important part of the hydrogeological terrain investigations, especially when spatial and temporal relations are not known precisely. There are many different methods available; among them not least important is careful visual inspection of the stream and its stream bed at regular intervals with the aim to detect phenomena which reflect surface water groundwater interactions. In parallel with the inspection various measurements can be performed. Together with usual water electro conductivity and water temperature we tested complimentary information which can be obtained with the concomitant regular sampling for δ18O determination in the river water course. Combination of all these information proved to be very useful in obtaining spatial trends in river characteristics and to determine relations between its water balance components. Testing of the methodology of hydrogeological mapping with the means of isotopes on the karstic Savica River during low flow period where water balance relations between its tributaries were not known before demonstrate the usefulness of the applied approach. Savica River is positioned in the north-west part of Slovenia in the centre of Triglav national Park which covers large part of East Julian Alps. River represents the main recharge of the Bohinj Lake, largest Slovenian natural lake. Savica River is short with the length of only 4.0 km and consists of two tributaries in the upper part; Mala Savica coming from the west and Velika Savica coming from the north-west. The first is recharged from several water caves of various lengths in which water level depends on hydrological conditions, consequently terminal end of the water in its riverbed part changes during the year. The second tributary is recharged from the 510 m long karstic cave with the entrance at 836 m a.s.l. where water disappears over 75 m high famous and picturesque waterfall. Geology of the catchment is predominantly formed by Dachstein limestone of Upper

  6. Relations between the structure of storage and the transport of chemical compounds in karstic aquifers

    NASA Astrophysics Data System (ADS)

    Vaute, L.; Drogue, C.; Garrelly, L.; Ghelfenstein, M.

    1997-12-01

    Study of the movement of chemical compounds naturally present in the water, or which result from pollution, are examined according to the reservoir structure in karstic aquifers. Structure is represented by a simple geometrical model; slow flow takes place in blocks with a network of low-permeability cracks. The blocks are separated by highly permeable karstic conduits that allow rapid flow, and these form the aquifer drainage system. The karst studied covers 110 km 2. It is fed by an interrupted stream draining a 35 km 2 non-karstic basin, contaminated at the entry to the karst by effluents from a sewage treatment station. The underground water reappears as a resurgence with an annual average flow of approximately 1 m 3 s -1, after an apparent underground course of 8 km in the karst. Several local sources of pollution (effluent from septic tanks) contaminate the underground water during its course. Sixteen measurement operations were performed at 12 water points, between the interrupted stream and the spring. Some sampling points were at drains, and others were in the low-permeability fissured blocks. Comparison at each point of the concentrations of 14 chemical compounds gave the following results: when pollutant discharge occurs in a permeable zone, movement is rapid in the drainage network formed by the karstic conduits, and does not reach the less permeable fissured blocks which are thus protected; however, if discharge is in a low-permeability zone, the flow does not allow rapid movement of the polluted water, and this increases the pollutant concentration at the discharge. This simple pattern can be upset by a reversal of the apparent piezometric gradient between a block and a conduit during floods or pumping; this may reverse flow directions and hence modify the movement of contaminants. The study made it possible to site five boreholes whose positions in the karstic structure were unknown, showing the interest of such an approach for the forecasting of the

  7. Large methane emission upon spring thaw from natural wetlands in the northern permafrost region

    SciTech Connect

    Song, Changchun; Xu, Xiaofeng; Sun, Xiaoxin; Tian, Hanqin; Sun, Li; Miao, Yuqing; Wang, Xianwei; Guo, Yuedong

    2012-01-01

    The permafrost carbon climate feedback is one of the major mechanisms in controlling the climate ecosystem interactions in northern high latitudes. Of this feedback, methane (CH4) emission from natural wetlands is critically important due to its high warming potential. The freeze thaw transition has been confirmed to play an important role in annual CH4 budget, yet the magnitude of this effect is uncertain. An intensive field campaign was carried out in the Sanjiang Plain, Northeast China to estimate the CH4 emission in the spring freeze thaw transition period. The observation concluded that a large CH4 source was caused by spring thaw; the maximum hourly emission rate was 48.6 g C m 2 h 1, more than three orders of the regularly observed CH4 emission rate in the growing season. In some sporadically observed 'hot spots', the spring thawing effect contributed to a large CH4 source of 31.3 10.1 g C m 2, which is approximately 80% of the previously calculated annual CH4 emission in the same study area. If our results are typical for natural wetlands in the Northern Hemisphere permafrost region, we estimate a global CH4 source strength of 0.5 1.0 Tg C (1 Tg =1012 g) caused by spring thaw in the Northern Hemisphere permafrost region in the year 2011. Combining with available satellite and flask data, a regional extrapolation reaches a temporal pattern of CH4 emission during 2003 2009 which is consistent with recently observed changes in atmospheric CH4 concentration in the high latitudes. This suggests that the CH4 emission upon spring thaw in the high latitudes might be enhanced by the projected climate warming. These findings indicate that the spring thawing effect is an important mechanism in the permafrost carbon climate feedback and needs to be incorporated in Earth system models.

  8. [Ichthyofauna of karstic wetlands under anthropic impact: the "petenes" of Campeche, Mexico].

    PubMed

    Torres-Castro, Ivette Liliana; Vega-Cendejas, María Eugenia; Schmitter-Soto, Juan Jacobo; Palacio-Aponte, Gerardo; Rodiles-Hernández, Rocío

    2009-01-01

    "Petenes" are small springs and associated streams that drain into wetlands near the coast in karstic areas. We studied composition, distribution, and abundance of the ichthyofauna in Los Petenes region (northwest Campeche). Two petenes displaying different degrees and types of anthropic impact were selected, Hampolol and El Remate. Hampolol has a smaller area but a longer derived stream; it is located within a protected area, but has been invaded by tilapia. El Remate is a popular spa, with no tilapia; it has a larger area but a shorter derived stream. At each "petén", several sites in the main spring, the associated stream, and secondary (temporary) springs were sampled in the rainy and dry seasons. Fishing gear was variable (throw net, gill net, small and large seine nets), but effort was uniform. We recorded temperature, dissolved oxygen, salinity, and depth at each site and season; also, we noted the different types and intensities of anthropic impact (channelization, presence of exotic species, recreational use, etc.) at each petén. We compared the petenes in terms of their environmental quality and fish fauna (composition, distribution, abundance, biomass); we also tested for effects of season and site within each petén. The study found 27 species of fishes, included in 18 genera and eight families, 24 species in Hampolol and 20 in El Remate. The geographical range of 'Cichlasoma' salvini, Rivulus tenuis, Phallichthys fairweatheri, Xiphophorus hellerii, and X maculatus is extended. The dominant species in both seasons was Astyanax (probable hybrids A. aeneus x altior at Hampolol, pure A. altior at El Remate), which contributed most of the abundance and biomass, together with Vieja synspila and Poecilia velifera. A significantly greater overall diversity (H'n=3.31) was recorded in Hampolol compared to El Remate (H'n=2.10). Cluster analysis of sites by species presence allowed distinction of two groupings within each petén: permanent waters (i.e., main

  9. Dynamics of natural prokaryotes, viruses, and heterotrophic nanoflagellates in alpine karstic groundwater.

    PubMed

    Wilhartitz, Inés C; Kirschner, Alexander K T; Brussaard, Corina P D; Fischer, Ulrike R; Wieltschnig, Claudia; Stadler, Hermann; Farnleitner, Andreas H

    2013-08-01

    Seasonal dynamics of naturally occurring prokaryotes, viruses, and heterotrophic nanoflagellates in two hydro-geologically contrasting alpine karst springs were monitored over three annual cycles. To our knowledge, this study is the first to shed light on the occurrence and possible interrelationships between these three groups in karstic groundwater. Hydrological and microbiological standard indicators were recovered simultaneously in order to estimate surface influence, especially during rainfall events. Data revealed a strong dependence of the microbial communities on the prevailing hydrological situation. Prokaryotic numbers averaged 5.1 × 10(7) and 1.3 × 10(7) cells L(-1) , and heterotrophic nanoflagellate abundance averaged 1.1 × 10(4) and 3 × 10(3) cells L(-1) in the limestone spring type (LKAS2) and the dolomitic spring type (DKAS1), respectively. Viral abundance in LKAS2 and DKAS1 averaged 9.4 × 10(8) and 1.1 × 10(8) viruses L(-1) . Unlike in DKAS1, the dynamic spring type LKAS2 revealed a clear difference between base flow and high discharge conditions. The virus-to-prokaryotes ratio was generally lower by a factor of 2-3, at higher average water residence times. Furthermore, the high prokaryotes-to-heterotrophic nanoflagellate ratios, namely about 4700 and 5400 for LKAS2 and DKAS1, respectively, pointed toward an uncoupling of these two groups in the planktonic fraction of alpine karstic aquifers. PMID:23828838

  10. Regional flow system delineation in arid karstic basins with sparse hydrogeologic data: Cuatro Cienegas Basin, Coahuila, Mexico

    NASA Astrophysics Data System (ADS)

    Wolaver, B. D.; Sharp, J. M.; Rodriguez, J. M.

    2006-12-01

    We develop procedures for the delineation of regional groundwater flow systems in arid, karstic basins with sparse hydrogeologic data using surface topography data, geologic mapping, permeability data, chloride concentrations of groundwater and precipitation, and measured discharge data. Aquifers are characterized using geographic information systems (GIS) for groundwater catchment delineation, an analytical model for interbasin flow evaluation, a chloride balance approach for recharge estimation, and a water budget for mapping contributing catchments over a 160,000 km2 region (24.87° to 28.70° north latitude and 100.68° west to 104.75° west longitude). The study area includes the Cuatro Cienegas Basin (CCB) of Coahuila, Mexico, a National Biosphere Reserve containing springs that support groundwater-dependent ecosystems and irrigated agriculture. Sustainable groundwater development is a key issue on the U.S. Mexico border. However, these procedures may be applicable in similar settings globally. We delineate groundwater catchments that contribute local and regional groundwater discharge to CCB springs and identify a large regional flow system includes mountain recharge from as both the Sierra Madre Oriental and Occidental.

  11. A classification of large amplitude oscillations of a spring-pendulum system

    NASA Technical Reports Server (NTRS)

    Broucke, R.

    1977-01-01

    We present a detailed classification of large amplitude oscillations of a non-integrable autonomous system with two degrees of freedom: the spring pendulum system. The classification is made with the method of invariant curves. The results show the importance of three types of motion: periodic, quasi-periodic and semi-ergodic. The numerical results are given for nine different values of the energy constant.

  12. Large uraniferous springs and associated uranium minerals, Shirley Mountains, Carbon County, Wyoming -- A preliminary report

    USGS Publications Warehouse

    Love, J.D.

    1963-01-01

    Ten springs along the southeast flank of the Shirley Mountains, Carbon County, Wyoming, have water containing from 12 to 27 parts per billion uranium, have a total estimated flow of 3 million gallons of clear fresh water per day, and have a combined annual output that may be as much as 166 pounds of uranium. These springs emerge from Pennsylvanian, Permian, and Triassic rocks on the east flank of a faulted anticlinal fold. In the vicinity of several springs, metatyuyamunite occurs locally in crystalline calcite veins averaging 3 feet in width but reaching a maximum of 24 feet. The veins are as much as several hundred feet long-and cut vertically through sandstones of Pennsylvanian age overlying the Madison Limestone (Mississippian). This limestone is believed to be the source of the calcite. A 3-foot channel sample cross one calcite vein contains 0.089 percent uranium. Lesser amounts of uranium were obtained from other channel samples. Selected samples contain from 0.39 to 2.2 percent uranium and from 0.25 to 0.86 percent vanadium. Three possible sources of the uranium are: (1) Precambrian rocks, (2) Paleozoic rocks, (3) Pliocene(?) tuffaceous strata that were deposited unconformably across older .rocks in both the graphically high and low parts of the area, but were subsequently removed by erosion except for a few small remnants, one of which contains carnotite. There is apparently a close genetic relation between the uraniferous springs and uranium mineralization in the calcite veins. Data from this locality illustrate how uraniferous ground water can be used as a guide in the exploration for areas where uranium deposits may occur. Also demonstrated is the fact that significant quantities of uranium are present in water of some large flowing springs.

  13. Dynamics of natural prokaryotes, viruses, and heterotrophic nanoflagellates in alpine karstic groundwater

    PubMed Central

    Wilhartitz, Inés C; Kirschner, Alexander K T; Brussaard, Corina P D; Fischer, Ulrike R; Wieltschnig, Claudia; Stadler, Hermann; Farnleitner, Andreas H

    2013-01-01

    Abstract Seasonal dynamics of naturally occurring prokaryotes, viruses, and heterotrophic nanoflagellates in two hydro-geologically contrasting alpine karst springs were monitored over three annual cycles. To our knowledge, this study is the first to shed light on the occurrence and possible interrelationships between these three groups in karstic groundwater. Hydrological and microbiological standard indicators were recovered simultaneously in order to estimate surface influence, especially during rainfall events. Data revealed a strong dependence of the microbial communities on the prevailing hydrological situation. Prokaryotic numbers averaged 5.1 × 107 and 1.3 × 107 cells L−1, and heterotrophic nanoflagellate abundance averaged 1.1 × 104 and 3 × 103 cells L−1 in the limestone spring type (LKAS2) and the dolomitic spring type (DKAS1), respectively. Viral abundance in LKAS2 and DKAS1 averaged 9.4 × 108 and 1.1 × 108 viruses L−1. Unlike in DKAS1, the dynamic spring type LKAS2 revealed a clear difference between base flow and high discharge conditions. The virus-to-prokaryotes ratio was generally lower by a factor of 2–3, at higher average water residence times. Furthermore, the high prokaryotes-to-heterotrophic nanoflagellate ratios, namely about 4700 and 5400 for LKAS2 and DKAS1, respectively, pointed toward an uncoupling of these two groups in the planktonic fraction of alpine karstic aquifers. Seasonal dynamics of naturally occurring prokaryotes, viruses and heterotrophic nanoflagellates in two hydro-geologically contrasting alpine karst springs were monitored over three annual cycles. Data revealed a strong dependence of the microbial communities on the prevailing hydrological situation. PMID:23828838

  14. Large aperture tunable-focus liquid lens using shape memory alloy spring.

    PubMed

    Hasan, Nazmul; Kim, Hanseup; Mastrangelo, Carlos H

    2016-06-13

    A tunable-focus large aperture liquid lens is constructed using shape memory alloy (SMA) springs as actuators. The lens mainly consists of a shallow liquid-filled cylindrical cavity bound by a thin compressible annular rim and encapsulated by a flexible circular membrane on the top of the rim and a rigid circular plate at the rim bottom. The lens optical power is adjusted by a controlled compression of the annular rim via actuation of the three shape-memory alloy (SMA) springs. Since the volume of the cavity liquid is constant, the rim compression bulges the flexible membrane outward thus reducing its radius of curvature and the lens focal length. The fabricated tunable lens demonstrated an optical power range of 0-4 diopters utilizing a driving voltage less than 3V. Lens optical wavefront profiling was done using a Shack-Hartmann sensor displaying a RMS wave front error of 0.77 µm and 1.68 µm at 0 D and + 4 D. The aperture diameter and thickness of the fabricated lens are 34 mm and 9 mm, respectively, while weighing 16.7 g. PMID:27410350

  15. Geological modeling and infiltration pattern of a karstic system based upon crossed geophysical methods and image-guided inversion

    NASA Astrophysics Data System (ADS)

    Duran, Lea; Jardani, Abderrahim; Fournier, Matthieu; Massei, Nicolas

    2015-04-01

    Karstic aquifers represent an important part of the water resources worldwide. Though they have been widely studied on many aspects, their geological and hydrogeological modeling is still complex. Geophysical methods can provide useful subsurface information for the characterization and mapping of karstic systems, especially when not accessible by speleology. The site investigated in this study is a sinkhole-spring system, with small diameter conduits that run within a chalk aquifer (Norville, in Upper Normandy, France). This site was investigated using several geophysical methods: electrical tomography, self-potential, mise-à-la-masse methods, and electromagnetic method (EM34). Coupling those results with boreholes data, a 3D geological model of the hydrogeological basin was established, including tectonic features as well as infiltration structures (sinkhole, covered dolines). The direction of the karstic conduits near the main sinkhole could be established, and the major fault was shown to be a hydraulic barrier. Also the average concentration of dolines on the basin could be estimated, as well as their depth. At last, several hypotheses could be made concerning the location of the main conduit network between the sinkhole and the spring, using previous hydrodynamic study of the site along with geophysical data. In order to validate the 3D geological model, an image-guided inversion of the apparent resistivity data was used. With this approach it is possible to use geological cross sections to constrain the inversion of apparent resistivity data, preserving both discontinuities and coherences in the inversion of the resistivity data. This method was used on the major fault, enabling to choose one geological interpretation over another (fault block structure near the fault, rather than important folding). The constrained inversion was also applied on covered dolines, to validate the interpretation of their shape and depth. Key words: Magnetic and electrical

  16. Analysis of long-term trends in flow from a Large Spring Complex in northern Florida

    USGS Publications Warehouse

    Grubbs, Jack W.

    2011-01-01

    Nonparametric regression analysis of historic flow and rainfall data was used to estimate declining flows in a river draining a large spring complex in northern Florida, USA. The analysis indicated that flow declined by an estimated 23 percent from 1900 to 2009. The rate of decline appeared to increase over time, from about 0.8 cubic foot per second per year during the period from 1930-1970, to about 1.1 cubic feet per second per year over the period from 1970-2009. The estimated decline for the period prior to 1980 is consistent with evidence indicating groundwater withdrawals to the east of the study area have diverted groundwater that formerly flowed toward the Ichetucknee River under predevelopment conditions.

  17. An unusually large phytoplankton spring bloom drives rapid changes in benthic diversity and ecosystem function

    NASA Astrophysics Data System (ADS)

    Zhang, Qingtian; Warwick, Richard M.; McNeill, Caroline L.; Widdicombe, Claire E.; Sheehan, Aaron; Widdicombe, Stephen

    2015-09-01

    In 2012, the Western English Channel experienced an unusually large and long-lived phytoplankton spring bloom. When compared with data from the past 20 years, average phytoplankton biomass at Station L4 (part of the Western Channel Observatory) was approximately 3× greater and lasted 50% longer than any previous year. Regular (mostly weekly) box core samples were collected from this site before, during and after the bloom to determine its impact on macrofaunal abundance, diversity, biomass, community structure and function. The spring bloom of 2012 was shown to support a large and rapid response in the majority of benthic taxa and functional groups. However, key differences in the precise nature of this response, as well as in its timing, was observed between different macrofauna feeding groups. Deposit feeders responded almost instantly at the start of the bloom, primarily thorough an increase in abundance. Suspension feeders and opportunistic/predatory/carnivorous taxa responded slightly more slowly and primarily with an increase in biomass. At the end of the bloom a rapid decline in macrobenthic abundance, diversity and biomass closely followed the decline in phytoplankton biomass. With suspension feeders showing evidence of this decline a few weeks before deposit feeders, it was concluded that this collapse in benthic communities was driven primarily by food availability and competition. However, it is possible that environmental hypoxia and the presence of toxic benthic cyanobacteria could also have contributed to this decline. This study shows evidence for strong benthic-pelagic coupling at L4; a shallow (50 m), coastal, fine-sand habitat. It also demonstrates that in such habitats, it is not just planktonic organisms that demonstrate clear community phenology. Different functional groups within the benthic assemblage will respond to the spring bloom in specific manner, with implications for key ecosystem functions and processes, such as secondary production

  18. Karstic water storage response to the recent droughts in Southwest China estimated from satellite gravimetry

    NASA Astrophysics Data System (ADS)

    Yao, Chaolong; Luo, Zhicai

    2015-12-01

    The water resources crisis is intensifying in Southwest China (SWC), which includes the world's largest continuous coverage of karst landforms, due to recent severe drought events. However, because of the special properties of karstic water system, such as strong heterogeneity, monitoring the variation of karstic water resources at large scales remains still difficult. Satellite gravimetry has emerged as an effective tool for investigating the global and regional water cycles. In this study, we used GRACE (Gravity Recovery and Climate Experiment) data from January 2003 to January 2013 to investigate karstic water storage variability over the karst region of SWC. We assessed the impacts of the recent severe droughts on karst water resources, including two heavy droughts in September 2010 to May 2010 and August 2011 to January 2012. Results show a slightly water increase tend during the studied period, but these two severe droughts have resulted in significant water depletion in the studied karst region. The latter drought during 2011 and 2012 caused more water deficits than that of the drought in 2010. Strong correlation between the variations of GRACE-based total water storage and precipitation suggests that climate change is the main driving force for the significant water absent over the studied karst region. As the world's largest continuous coverage karst aquifer, the karst region of SWC offers an example of GRACE applications to a karst system incisively and will benefit for water management from a long-term perspective in karst systems throughout the world.

  19. Transfer function approach for artificial tracer test interpretation in karstic systems

    NASA Astrophysics Data System (ADS)

    Labat, D.; Mangin, A.

    2015-10-01

    A karstic formation consists in a three-dimensional hydrological system which involves horizontal and vertical, diphasic or saturated water transfers characterised by a large range of velocity. These subsurface flow processes correspond to various water pathways through fractured, fissured, and underground streams or conduits leading to a nonlinear global behaviour of the system. An efficient way of investigating of a karstic system behaviour consists in the injection of artificial tracer tests at loss points and in careful analysis of the recovery tracer fluxes at one or several outlets of the systems. These injections are also an efficient way of providing hypotheses on characteristic time of contaminant transfer in these type of aquifers. Here, we propose a Laplace-transform transfer function of the Residence Time Distribution function that allows to discriminate between a quick-flow advection-dominated component and a slow-flow advection-dispersion/dominated component in the artificial tracer transfer in the system. We apply this transfer function on five high resolution sampling rate artificial tracer tests operated on the Baget system in the Pyrenees (France) in order to illustrate the advantages and limitations of this approach. We provide then an interpretation of the relationship between tracer test recovery shape and karstic system organisation between inlet and outlet site.

  20. Identification of Karstic Caves by Utilizing Two-Dimensional Electrical Resistivity Imaging (ERI) Method

    NASA Astrophysics Data System (ADS)

    Uçar, Fatih; Aktürk, Özgür

    2015-04-01

    The region consisting of easily soluble rocks is generally defined as karstic terrain and it is characterized by surface collapse and small or large scale dissolution voids on rock surface. Formation and expansion of these voids may cause dangerous situation during surface/subsurface construction works. Therefore, it is important to determine the location, size and dimension of karstic caves. Geophysical investigations are very helpful in determining the boundaries of geological subsurface structures. In order to determine subsurface profile and characteristic of soil, surface geophysical methods can be successfully applied. Electrical Resistivity Imaging (ERI) is the most important methods among the convenient and commonly used methods to determine subsurface profile. By using this method, cavernous and weathered zones can be determined easily. Within the scope of this study, near surface profiles were determined by utilizing ERI at Akdeniz University Campus and Masa Dağı region located in the city of Antalya, Turkey. The results obtained from four different locations in the Akdeniz University campus compared only with Vertical Electrical Sounding (VES) analyses. Since topographic cross-section is clearly seen in two different locations around Masa Dağı location, ERI results were superimposed with topography and also compared with VES. As a result, presences of subsurface cavities were determined and illustrated using 2D colorful images. Keywords: ERI, VES, Karstic terrain, Cave, Antalya

  1. Karstic slope "breathing": morpho-structural influence and hazard implications

    NASA Astrophysics Data System (ADS)

    Devoti, Roberto; Falcucci, Emanuela; Gori, Stefano; Eliana Poli, Maria; Zanferrari, Adriano; Braitenberg, Carla; Fabris, Paolo; Grillo, Barbara; Zuliani, David

    2016-04-01

    The study refers to the active slope deformation detected by GPS and tiltmeter stations in the Cansiglio karstic plateau located in the western Carnic Prealps (NE Italy). The observed transient deformation clearly correlates with the rainfall, so that the southernmost border of the Plateau reacts instantly to heavy rains displaying a "back and forth" deformation up to a few centimeters wide, with different time constants, demonstrating a response to different catchment volumes. We carried out a field survey along the southern Cansiglio slope, to achieve structural characterization of the relief and to verify the possible relation between structural features and the peculiar geomorphological setting dominated by widespread karstic features. The Cansiglio plateau develops on the frontal ramp anticline of the Cansiglio thrust, an about ENE-WSW trending, SSE-verging, low angle thrust, belonging to the Neogene-Quaternary front of the eastern Southern Alps. The Cansiglio thrust outcrops at the base of the Cansiglio plateau, where it overlaps the Mesozoic carbonates on the Miocene-Quaternary terrigenous succession. All along its length cataclastic limestone largely outcrop. The Cansiglio thrust is bordered by two transfer zones probably inherited from the Mesozoic paleogeography: the Caneva fault in the west and the Col Longone fault in the east. The carbonatic massif is also characterized by a series of about northward steeply dipping reverse minor faults and a set of subvertical joints parallel to the axes of the Cansiglio anticline. Other NNW-SSE and NNE-SSW conjugate faults and fractures perpendicular to the Cansiglio southern slope are also identified. This structural setting affect pervasively the whole slope and may determine centimetre- to metre-scale rock prisms. Interestingly, along the topmost portion of the slope, some dolines and swallow holes show an incipient coalescence, that trends parallel to the massif front and to the deformation zones related to the

  2. Isotope analyses of fossil small mammals in karstic sites

    NASA Astrophysics Data System (ADS)

    Garcia Alix, Antonio; Delgado Huertas, Antonio

    2016-04-01

    Fossil skeletal accumulations in kartstic complexes, such as caves, are quite common, especially during the Pliocene and Quaternary. These fossil assemblages are sometimes difficult to study, as specimens from different ages can be found together (time averaging). The traditional approach to study this kind of paleontological sites was taphonomic (understanding the origin and other factors affecting the bone accumulation) and/or taxonomic (systematic description of the remains). However, other kinds of analyses, such as biogeochemical techniques to reconstruct past diets and environments, are being more frequently used. Small-mammals have a wide geographical distribution, and their remains (bones and teeth) are extensively represented in the fossil record; therefore, isotopic analyses in fossil small-mammals are a powerful tool to reconstruct paleoenvironments. Field samples for small-mammal studies yield large amounts of sediment-residues that need to be reduced in the laboratory (usually by means of diluted hydrochloric or acetic acid). Therefore, samples of fossil small-mammal for isotopic analyses usually receive two different acid treatments: one to reduce the carbonate residue of the sediment, and afterwards another one to remove digenetic carbonates from the ground sample. Those treatments, along with the small size of the remains, may increase the probability of chemical fractionation during those pre-treatment stages. Those acid treatments are even more aggressive in kasrtic fossil localities, as limestone has to be dissolved to extract the small mammal remains. In this abstract, we present the results of two different treatments carried out in limestone from the Pliocene karstic locality of Moreda (Guadix Basin, Spain) and a control sample. One batch of samples were treated with a solution of 1M acetic acid-acetate calcium buffer (ph 4,5), and the rest with diluted acetic acid (at 15% concentration, Ph 2,2), which is the most used to reduce the sediments

  3. Development of a large-area chip network with multidevice integration using a stretchable electroplated copper spring

    NASA Astrophysics Data System (ADS)

    Sung, Wei-Lun; Chen, Chih-Chung; Huang, Kevin; Fang, Weileun

    2016-02-01

    This study designed and implemented the multidevice integration of a flexible large-area chip network using a stretchable electroplated copper spring. The functional devices are directly implemented and integrated on the nodes of a 2D chip network distribution, and the nodes are mechanically and electrically connected to surrounding nodes by stretchable copper springs. The springs can stretch and expand the distance between functional devices by several orders of magnitude to construct a large-area chip network with interconnected devices. The advantages of this approach are that (1) the existing and mature process technologies and materials for semiconductors in large-area applications are used, (2) stretchable electroplated copper springs with larger failure strain and good conductivity act as both mechanical and electrical connections between nodes, (3) rigid nodes act as hubs for device implementation and integration with microfabrication processes, and (4) the chip network can be applied to 2D curved (spherical) surfaces for flexible electronics. In application, the proposed expandable chip network using stretchable springs with integration of various devices (such as proximity and temperature sensors and light-emitting diode (LED) chips) has been successfully implemented and tested. The results show the chip network with integrated sensors performs as expected on a 2D plane distribution as verified by measurements. Moreover, LED chips have been integrated as an example to show that the proposed design can be used for flexible electronics applications.

  4. Lipid reserves of Lesser Scaup (Aythya Affinis) migrating across a large landscape are consistent with the "Spring Condition" hypothesis

    USGS Publications Warehouse

    Anteau, M.J.; Afton, A.D.

    2009-01-01

    The "spring condition" hypothesis (SCH) states that nutrition during spring migration affects survival, reproductive success, and, ultimately, population size of migratory birds. The North American population of Lesser Scaup (Aythya affinis) has experienced a marked decline, apparently because of poor recruitment. An important prediction of the SCH is that female Lesser Scaup have low lipid reserves during spring migration. We previously reported that lipid reserves and body mass of females collected on migratory stopover areas in northwestern Minnesota in springs 2000-2001 were lower than those on the same areas in the 1980s and markedly lower than those collected at Pool 19 of the Mississippi River in 2000-2001, an important preceding stopover area. However, it was unclear whether these findings represented a site-specific result or a landscape-scale phenomenon. Accordingly, we examined lipid and body mass of 641 female Lesser Scaup migrating across seven eco-physiographic regions of Iowa, Minnesota, and North Dakota during springs 2003-2005. We found that lipids and body mass of females throughout the Upper Midwest were similar to or less than the low values documented in northwestern Minnesota in springs 2000-2001 and markedly lower than those of females at Pool 19 in springs 2000-2001. Accordingly, our results are consistent with a prediction of the SCH, because lipid and body mass of females are low throughout this large landscape, lower than at an important preceding stopover area, and lower than all historical values. Finally, our results suggest the potential for cross-seasonal influences of nutrition on recruitment and that a stronger management focus on spring migration habitats may be necessary for conservation and recovery of declining migratory birds, especially Lesser Scaup. ?? The American Ornithologists' Union, 2009.

  5. A large-stroke shape memory alloy spring actuator using double-coil configuration

    NASA Astrophysics Data System (ADS)

    Kim, Seung-Won; Lee, Jong-Gu; An, Sungmin; Cho, Maenghyo; Cho, Kyu-Jin

    2015-09-01

    One way to increase the range of motion of shape memory alloy (SMA) actuators is to create displacements of the SMA associated with not only the deformation from straining but also rigid-body motion from translation and rotation. Rigid-body motion allows the SMA to create larger displacements without exceeding the maximum recovery strain so that the SMA actuators can have a larger shape recovery ratio. To improve the linear actuation stroke of SMA wire actuators, a novel SMA spring actuator is proposed that employs a double-coil geometry that allows the displacement of the SMA to be mainly induced by rigid-body motion. A double-coil SMA spring actuator is fabricated by coiling an SMA wire twice so that the double coiling results in a reduction of the initial length of the double-coil SMA spring actuator. The effects of the geometric parameters on the actuation characteristic of a double-coil SMA spring actuator are verified numerically by finite element analysis and experimentally according to a parametric study of the geometric parameters. The displacement-to-force profile of the double-coil SMA spring actuator is nonlinear, and the spring stiffness changes when the actuator transforms its configuration from a double-coil shape to a single-coil shape. According to the results of the parametric study, increasing the wire diameter increases both primary and secondary coil stiffness, and increasing the primary inner coil diameter decreases both primary and secondary coil stiffness, whereas increasing the secondary inner coil diameter decreases only the secondary coil stiffness. The result shows that one of the double-coil SMA spring actuators with an initial length of 8 mm has a recovery ratio of 1250%, while the recovery ratio of the single-coil SMA spring actuator with the same geometric parameters is 432%.

  6. Mapping and modelling spatial patterns of dominant processes in a karstic catchment

    NASA Astrophysics Data System (ADS)

    Reszler, Christian; Stadler, Hermann; Komma, Jürgen; Blöschl, Günter

    2014-05-01

    This paper presents a framework of combining hydrogeological mapping and hydrological modelling for dominant processes identification in karstic catchments. The aim is to identify areas with a potential of surface erosion and solute input into a karst system. Hydrogeological mapping is based on a mapping catalogue, where the items can be transferred directly to model structure and parameters. The items contain mappable properties such as geological units, overlaying loose material/debris and soils. The synthesis of these properties leads to identification of dominant hydrological mechanisms, particularly the interplay between direct infiltration and surface runoff. Model structure and a priori model parameters can be set and modified based on hydrogeological expert evaluation. This enhances the calibration and validation procedure and includes the formulation of a conceptual karst drainage module. Besides discharge data of springs water quality data (e.g. SAC 254) are used to obtain a better understanding of the karst system and its drainage characteristics and to estimate particle travel time.

  7. Ferruginous thermal spring complexes, northwest Tasmania: evidence that far-field stresses acting on a fracture mesh can open and maintain vertical flow in carbonate terrains

    NASA Astrophysics Data System (ADS)

    Davidson, Garry J.; Bavea, Michael; Harris, Kathryn

    2011-11-01

    Far-field stress changes in the southern Australian plate since 5 Ma have produced significant areas of uplift and seismicity. In northwest Tasmania, there is evidence that this stress reorientation to maximum horizontal NW-SE stress has influenced meteoric-derived thermal (15-20°C) discharge patterns of confined karstic aquifers, by placing pre-existing NW-trending faults/fractures into a dilated state or a critically stressed state. Previous studies have shown that spring discharge has operated continuously for at least 65,000 years, and has transported large volumes of solutes to the surface to be deposited as mounds of calcite-goethite-silica up to 7 m high. The thermal spring chemistry at one site, Mella, is consistent with descent to at least 1.2-1.5 km, although the hinterland within 50 km is less than 500 m elevation. Thermal spring chemistry is consistent with most of the deep water-rock interaction occurring in low-strontium Smithton Dolomite. While some of this water is discharged at springs, some instead intersects shallow zones of NE-fracture-controlled rock (2 × 4 km in area) with karstic permeability where, although confined and subject to a NE-directed hydraulic gradient, it circulates and cools to ambient temperature, with only minor mixing with other groundwaters.

  8. Influence of snow thawing regime changes on the outflow from karstic aquifer

    NASA Astrophysics Data System (ADS)

    Brenčič, Mihael; Vreča, Polona

    2013-04-01

    Savica River is a natural phenomenon with wide spectrum of different high Alpine karstic features interesting for thorough and precise hydrogeological. It flows out from the 300 m long flooded cave, represents one of the largest Slovenian karstic springs and the main tributary to the biggest Slovene natural lake, Lake Bohinj. The discharge of Savica is in the interval between 0.03 m3/s to 132 m3/s. The annual discharge hydrograph of Savica consist of two different parts, first part belongs to long spring thawing period that lasts up to 4 months, and the other part is typical for the fast infiltration and fast outflow represented with high discharges in autumn months. High Qmax/Qmin ratio indicates highly developed karstic channel network inside of the Dachstein carbonate rocks. In the major part of recharge area average annual precipitation is up to 3200 mm/year. Real evapotranspiration is low and well below 550 m/year. Average annual number of days with the air temperature bellow frost point is estimated between 70 to 100 days and average fresh snow thickness for the period between 1961 and 1990 was over 4.2 m. In the Savica River hinterland typical weather situation is represented by incoming wet and relatively warm air masses coming from the southwest. In the Julian Alps where recharge area of Savica River is positioned diminishing of snow water equivalent and the thickness of the snow cover is experienced. Dynamics of snow thawing has consequences on the outflow regime in Savica River and the level of theses influences is investigated with the analyses of the Savica River total hydrograph. Total available hydrograph of river Savica consists of data in the period between year 1954 and year 2009, with gaps between years 1973 and 1983 and years 1990 and 1996. Annual hydrograph was divided into snow thawing dominated period and rainfall dominated period. It was determined that during observation period the ratio between snow dominated to rainfall dominated period

  9. Large methane emissions from a subarctic lake during spring thaw: Mechanisms and landscape significance

    NASA Astrophysics Data System (ADS)

    Jammet, Mathilde; Crill, Patrick; Dengel, Sigrid; Friborg, Thomas

    2015-11-01

    The ice-cover season and subsequent spring thaw are thought to be of particular importance for the biogeochemical cycle of northern lakes and wetlands. Yet the magnitude of their methane emissions during an entire cold season is uncertain due to scarce measurements. While wetlands are known to be the highest natural emitters of methane, emissions from northern lakes are an uncertain component of terrestrial carbon budgets. To evaluate the importance of methane emissions from a subarctic lake during winter and spring, surface methane fluxes were recorded with the eddy covariance method in a subarctic fen-type wetland and in an adjacent shallow lake, from freezeup to complete ice out. The fen was a steady emitter of methane throughout winter. While no detectable flux was observed from the ice-covered lake surface during winter, it was the largest methane source of the landscape in spring, with a cumulative release 1.7-fold higher than at the fen, accounting for 53% of annual lake emissions. The high temporal resolution of the measurements allowed making a direct link between breakdown of the temperature stratification after ice breakup and the highest release of methane from the lake surface. A sediment upwelling at the end of the thaw season likely contributed to these emissions. We suggest that, unlike wetlands, shallow seasonally ice-covered lakes can have their highest methane emission potential in the cold season, likely dominating the spring methane release of subarctic landscapes with high lake coverage.

  10. Numerical modeling of the spring thermal bar and pollutant transport in a large lake

    NASA Astrophysics Data System (ADS)

    Tsydenov, Bair O.; Kay, Anthony; Starchenko, Alexander V.

    2016-08-01

    The spring riverine thermal bar phenomenon is investigated numerically on an example of Lake Baikal, and the spread of pollutants coming from the Selenga River is forecast using the 2.5 D non-hydrostatic model in the Boussinesq approximation. This hydrodynamic model takes into account the diurnal variability of the heat fluxes on the lake surface and the effects of wind and the Earth's rotation. The results of numerical modeling show that the variability of the total heat flux over 24 h plays a significant role in the variation of the thermal bar movement rate that contributes to the rapid mixing of impurities entering with river water.

  11. Calcite biomineralization by bacterial isolates from the recently discovered pristine karstic herrenberg cave.

    PubMed

    Rusznyák, Anna; Akob, Denise M; Nietzsche, Sándor; Eusterhues, Karin; Totsche, Kai Uwe; Neu, Thomas R; Frosch, Torsten; Popp, Jürgen; Keiner, Robert; Geletneky, Jörn; Katzschmann, Lutz; Schulze, Ernst-Detlef; Küsel, Kirsten

    2012-02-01

    Karstic caves represent one of the most important subterranean carbon storages on Earth and provide windows into the subsurface. The recent discovery of the Herrenberg Cave, Germany, gave us the opportunity to investigate the diversity and potential role of bacteria in carbonate mineral formation. Calcite was the only mineral observed by Raman spectroscopy to precipitate as stalactites from seepage water. Bacterial cells were found on the surface and interior of stalactites by confocal laser scanning microscopy. Proteobacteria dominated the microbial communities inhabiting stalactites, representing more than 70% of total 16S rRNA gene clones. Proteobacteria formed 22 to 34% of the detected communities in fluvial sediments, and a large fraction of these bacteria were also metabolically active. A total of 9 isolates, belonging to the genera Arthrobacter, Flavobacterium, Pseudomonas, Rhodococcus, Serratia, and Stenotrophomonas, grew on alkaline carbonate-precipitating medium. Two cultures with the most intense precipitate formation, Arthrobacter sulfonivorans and Rhodococcus globerulus, grew as aggregates, produced extracellular polymeric substances (EPS), and formed mixtures of calcite, vaterite, and monohydrocalcite. R. globerulus formed idiomorphous crystals with rhombohedral morphology, whereas A. sulfonivorans formed xenomorphous globular crystals, evidence for taxon-specific crystal morphologies. The results of this study highlighted the importance of combining various techniques in order to understand the geomicrobiology of karstic caves, but further studies are needed to determine whether the mineralogical biosignatures found in nutrient-rich media can also be found in oligotrophic caves. PMID:22179248

  12. Calcite Biomineralization by Bacterial Isolates from the Recently Discovered Pristine Karstic Herrenberg Cave

    PubMed Central

    Rusznyák, Anna; Akob, Denise M.; Nietzsche, Sándor; Eusterhues, Karin; Totsche, Kai Uwe; Neu, Thomas R.; Frosch, Torsten; Popp, Jürgen; Keiner, Robert; Geletneky, Jörn; Katzschmann, Lutz; Schulze, Ernst-Detlef

    2012-01-01

    Karstic caves represent one of the most important subterranean carbon storages on Earth and provide windows into the subsurface. The recent discovery of the Herrenberg Cave, Germany, gave us the opportunity to investigate the diversity and potential role of bacteria in carbonate mineral formation. Calcite was the only mineral observed by Raman spectroscopy to precipitate as stalactites from seepage water. Bacterial cells were found on the surface and interior of stalactites by confocal laser scanning microscopy. Proteobacteria dominated the microbial communities inhabiting stalactites, representing more than 70% of total 16S rRNA gene clones. Proteobacteria formed 22 to 34% of the detected communities in fluvial sediments, and a large fraction of these bacteria were also metabolically active. A total of 9 isolates, belonging to the genera Arthrobacter, Flavobacterium, Pseudomonas, Rhodococcus, Serratia, and Stenotrophomonas, grew on alkaline carbonate-precipitating medium. Two cultures with the most intense precipitate formation, Arthrobacter sulfonivorans and Rhodococcus globerulus, grew as aggregates, produced extracellular polymeric substances (EPS), and formed mixtures of calcite, vaterite, and monohydrocalcite. R. globerulus formed idiomorphous crystals with rhombohedral morphology, whereas A. sulfonivorans formed xenomorphous globular crystals, evidence for taxon-specific crystal morphologies. The results of this study highlighted the importance of combining various techniques in order to understand the geomicrobiology of karstic caves, but further studies are needed to determine whether the mineralogical biosignatures found in nutrient-rich media can also be found in oligotrophic caves. PMID:22179248

  13. Evaluation of karstic aquifers contribution to streams in Southwest China

    NASA Astrophysics Data System (ADS)

    Shi, P.; Chen, X.; Qu, S.; Cui, Y.

    2009-12-01

    Guizhou Province in Southwest China is located in the east side of the Yunnan-Guizhou Plateau. It covers 17,600km2 and has a population of 32.4 million. Guizhou Province has one of the largest, continuous karst areas in the world. About 73% of Guizhou is karst, which is underlain by up to 10,000m of soluble carbonate rocks, 10% is hilly, and only 3% is classified as flat (Zeng, 1994). Mountainous areas with slopes of more than 15o account for 60.0% of its area (Li et al., 2002). The region contains a full suite of karst landforms, including poljes, cockpits, towers and dolines. Guizhou is within the fragile karst ecosystem belt that extends from the Mediterranean, through the Middle East and parts of southern Asin, to the central Americas (Yuan, 1997). It is a mountainous agricultural province, and agricultural land is very limited. The best arable lands are found in flat areas located in karst valleys, basins, or closed depressions, where major settlements are also situated. In such area, karstic aquifers significantly contribute to streams in most of Guizhou’s river basins, so studies on karst water resources have great importance for Guizhou. Karstic aquifer contributions are generally emerging at several locations near the river bed and are not readily measured by direct hydrometric methods. In this study, the extent of karstic aquifer contributions to a stream will be investigated by a statistical analysis of baseflow incices and recession coefficients of recession curves. Fifteen stream gauging stations on different, independent basins in Guizhou are selected. Recession periods of the streams are simulated by exponential curve models. Recession coefficient series of the stream gauging stations are statistically investigated. The comparison of various statistical parameters shows that the recession coefficient series are fairly related to the karstic aquifer contributions.

  14. Natural and induced endoreic hydrological conditions in the Alta Murgia karstic region (Apulia, Southern Italy)

    NASA Astrophysics Data System (ADS)

    Canora, F.; Fidelibus, M. D.; Spilotro, G.

    2009-04-01

    A study aimed at understanding the hydrological processes in karst areas related to the presence of natural and artificial endoreic basins and their modification due to land use change, as well as the influence of above factors on the infiltration rate has been carried out in the Alta Murgia region (Apulia, Southern Italy). The region is a Cretaceous limestone plateau of the Apulian platform, characterized by a mature karstic landscape: due to its elevation, climatic conditions and lithology, the plateau constitutes the main recharge area of the Murgia aquifer. The typical karst topography is essentially related to the subterranean drainage (sinkholes, caves, conduit): surface and subsurface karst geomorphology is strictly interrelated with hydrology. The morphological features of the karstic plateau are defined by the high density of surface karstic forms (mainly dolines), the presence of exposed karst and karren fields, as well as by the extensive outcrop of fractured rocks. Karst surface shows, on the bottom of the morpho-structural depressions called "lame", natural distribution of modest deposits of "terra rossa" and regolith. The "lame" work as streams during and after intense rainfall events, often outlining a primordial ephemeral hydrographical network, frequently convergent towards dolines, poljes or endoreic basins. Alta Murgia shows many natural endoreic basin conditions in a quite flat morphology. In this environment, when intense rainfall events cover large areas and rainfall intensity exceeds the infiltration capacity of soils and/or sinkholes, significant runoff amounts are produced and stored in the basins causing floods. Most of the natural endoreic basins are small and independent: while the majority of them continue functioning as endoreic even in presence of extreme events of high return time, others (quasi-endoreic), under the same circumstances can start contributing to other basins, due to exceeding their water storage capability. This way

  15. Later Middle Pleistocene human remains from the Almonda Karstic system, Torres Novas, Portugal.

    PubMed

    Trinkaus, Erik; Marks, Anthony E; Brugal, Jean Philip; Bailey, Shara E; Rink, W Jack; Richter, Daniel

    2003-09-01

    Later Middle Pleistocene archeological deposits of the Galeria Pesada (Gruta da Aroeira), Almonda Karstic System, Torres Novas, Portugal, yielded two archaic human teeth, a mandibular canine and a maxillary third molar. The C(1)presents moderate and asymmetrical shoveling with a stout root. The slightly worn M(3)exhibits at least four cusps with a large hypocone, three roots with large radicular plates, and an absence of taurodontism. They are moderately large for later Middle Pleistocene humans in their buccolingual crown diameters, although the M(3)mesiodistal diameter is modest. The C(1)exhibits labial calculus and multiple linear hypoplastic defects, but the M(3)is lesion free. Both teeth are morphologically similar to those of other Middle Pleistocene European humans and reinforce a pattern of dental hypertrophy among these archaic Homo. PMID:14580591

  16. Effect of the 1950s large-scale migration for land reclamation on spring dust storms in Northwest China

    NASA Astrophysics Data System (ADS)

    Ta, Wanquan; Dong, Zhibao; Sanzhi, Caidan

    During the 1950s, China experienced large-scale human migration for the purposes of land reclamation, industrialization, and construction in Northwest China, with a peak of nearly 70 million migrants in 1959 during the Great Leap Forward period. These intense human activities were responsible for the 1950s' dust storms in Northwest China. Due to large-scale reclamations, the number of spring dust storm days did not show much relationship with the number of spring strong wind days in the Tarim Basin and the Hexi Corridor, but they did correlate with the increase in annual land reclamation areas, with correlation coefficients of 0.82 and 0.88, respectively, in the two regions. Indeed, severe dust storm outbreaks (visibility less than 200 m) in Xinjiang, Gansu and Qinghai provinces in Northwest China were also found to be positively correlated with the number of annual immigrants and the annual increase in cultivated land areas in the period 1953-1968, with coefficients of 0.62 and 0.65, respectively.

  17. Identification of glacial meltwater runoff in a karstic environment and its implication for present and future water availability

    NASA Astrophysics Data System (ADS)

    Finger, D.; Hugentobler, A.; Huss, M.; Voinesco, A.; Wernli, H.; Fischer, D.; Weber, E.; Jeannin, P.-Y.; Kauzlaric, M.; Wirz, A.; Vennemann, T.; Hüsler, F.; Schädler, B.; Weingartner, R.

    2013-08-01

    Glaciers all over the world are expected to continue to retreat due to the global warming throughout the 21st century. Consequently, future seasonal water availability might become scarce once glacier areas have declined below a certain threshold affecting future water management strategies. Particular attention should be paid to glaciers located in a karstic environment, as parts of the meltwater can be drained by underlying karst systems, making it difficult to assess water availability. In this study tracer experiments, karst modeling and glacier melt modeling are combined in order to identify flow paths in a high alpine, glacierized, karstic environment (Glacier de la Plaine Morte, Switzerland) and to investigate current and predict future downstream water availability. Flow paths through the karst underground were determined with natural and fluorescent tracers. Subsequently, geologic information and the findings from tracer experiments were assembled in a karst model. Finally, glacier melt projections driven with a climate scenario were performed to discuss future water availability in the area surrounding the glacier. The results suggest that during late summer glacier meltwater is rapidly drained through well-developed channels at the glacier bottom to the north of the glacier, while during low flow season meltwater enters into the karst and is drained to the south. Climate change projections with the glacier melt model reveal that by the end of the century glacier melt will be significantly reduced in the summer, jeopardizing water availability in glacier-fed karst springs.

  18. Identification of glacial melt water runoff in a karstic environment and its implication for present and future water availability

    NASA Astrophysics Data System (ADS)

    Finger, D.; Hugentobler, A.; Huss, M.; Voinesco, A.; Wernli, H.; Fischer, D.; Weber, E.; Jeannin, P.-Y.; Kauzlaric, M.; Wirz, A.; Vennemann, T.; Hüsler, F.; Schädler, B.; Weingartner, R.

    2013-03-01

    Glaciers all over the world are expected to continue to retreat due to the global warming throughout the 21st century. Consequently, future seasonal water availability might become scarce once glacier areas have declined below a certain threshold affecting future water management strategies. Particular attention should be paid to glaciers located in a karstic environment, as parts of the melt water can be drained by souterrain karst systems. In this study tracer experiments, karst modeling and glacier melt modeling are combined in order to identify flow paths in a high alpine, glacierized, karstic environment (Glacier de la Plaine Morte, Switzerland) and to investigate current and predict future downstream water availability. Flow paths through the karst underground were determined with natural and fluorescent tracers. Subsequently, tracer results and geologic information were assembled in a karst model. Finally, glacier melt projections driven with a climate scenario were performed to discuss future water availability in the area surrounding the glacier. The results suggest that during late summer glacier melt water is rapidly drained through well-developed channels at the glacier bottom to the north of the glacier, while during low flow season melt water enters into the karst and is drained to the south. Climate change projections reveal that by the end of the century glacier melt will be significantly reduced in the summer, jeopardizing water availability in glacier-fed karst springs.

  19. Characterization of the hydrology, water chemistry, and aquatic communities of selected springs in the St. Johns River Water Management District, Florida, 2004

    USGS Publications Warehouse

    Phelps, G.G.; Walsh, Stephen J.; Gerwig, Robert M.; Tate, William B.

    2006-01-01

    The hydrology, water chemistry, and aquatic communities of Silver Springs, De Leon Spring, Gemini Springs, and Green Spring in the St. Johns River Water Management District, Florida, were studied in 2004 to provide a better understanding of each spring and to compile data of potential use in future water-management decisions. Ground water that discharges from these and other north-central Florida springs originates from the Upper Floridan aquifer of the Floridan aquifer system, a karstic limestone aquifer that extends throughout most of the State's peninsula. This report summarizes data about flow, water chemistry, and aquatic communities, including benthic invertebrates, fishes, algae, and aquatic macrophytes collected by the U.S. Geological Survey, the St. Johns River Water Management District, and the Florida Department of Environmental Protection during 2004, as well as some previously collected data. Differences in water chemistry among these springs reflect local differences in water chemistry in the Upper Floridan aquifer. The three major springs sampled at the Silver Springs group (the Main Spring, Blue Grotto, and the Abyss) have similar proportions of cations and anions but vary in nitrate and dissolved oxygen concentrations. Water from Gemini Springs and Green Spring has higher proportions of sodium and chloride than the Silver Springs group. Water from De Leon Spring also has higher proportions of sodium and chloride than the Silver Springs group but lower proportions of calcium and bicarbonate. Nitrate concentrations have increased over the period of record at all of the springs except Green Spring. Compounds commonly found in wastewater were found in all the springs sampled. The most commonly detected compound was the insect repellant N,N'-diethyl-methyl-toluamide (DEET), which was found in all the springs sampled except De Leon Spring. The pesticide atrazine and its degradate 2-chloro-4-isopropylamino-6-amino-s-triazine (CIAT) were detected in water

  20. Low spring index, large displacement Shape Memory Alloy (SMA) coil actuators for use in macro- and micro-systems

    NASA Astrophysics Data System (ADS)

    Holschuh, Brad; Newman, Dava

    2014-03-01

    Shape memory alloys (SMA) offer unique shape changing characteristics that can be exploited to produce low­ mass, low-bulk, large-stroke actuators. We are investigating the use of low spring index (defined as the ratio of coil diameter to wire diameter) SMA coils for use as actuators in morphing aerospace systems. Specifically, we describe the development and characterization of minimum achievable spring index coiled actuators made from 0.3048 mm (0.012") diameter shape memory alloy (SMA) wire for integration in textile architectures for future compression space suit applications. Production and shape setting of the coiled actuators, as well as experimental test methods, are described. Force, length and voltage relationships for multiple coil actuators are reported and discussed. The actuators exhibit a highly linear (R2 < 0.99) relationship between isometric blocking force and coil displacement, which is consistent with current SMA coil models; and SMA coil actuators demonstrate the ability to produce significant linear forces (i.e., greater than 8 N per coil) at strains up to 3x their initial (i.e., fully coiled) length. Discussions of both the potential use of these actuators in future compression space suit designs, and the broader viability of these actuators in both macro- and micro-systems, are presented.

  1. Groundwater-flow modeling in the Yucatan karstic aquifer, Mexico

    NASA Astrophysics Data System (ADS)

    González-Herrera, Roger; Sánchez-y-Pinto, Ismael; Gamboa-Vargas, José

    2002-09-01

    The current conceptual model of the unconfined karstic aquifer in the Yucatan Peninsula, Mexico, is that a fresh-water lens floats above denser saline water that penetrates more than 40 km inland. The transmissivity of the aquifer is very high so the hydraulic gradient is very low, ranging from 7-10 mm/km through most of the northern part of the peninsula. The computer modeling program AQUIFER was used to investigate the regional groundwater flow in the aquifer. The karstified zone was modeled using the assumption that it acts hydraulically similar to a granular, porous medium. As part of the calibration, the following hypotheses were tested: (1) karstic features play an important role in the groundwater-flow system; (2) a ring or belt of sinkholes in the area is a manifestation of a zone of high transmissivity that facilitates the channeling of groundwater toward the Gulf of Mexico; and (3) the geologic features in the southern part of Yucatan influence the groundwater-flow system. The model shows that the Sierrita de Ticul fault, in the southwestern part of the study area, acts as a flow barrier and head values decline toward the northeast. The modeling also shows that the regional flow-system dynamics have not been altered despite the large number of pumping wells because the volume of water pumped is small compared with the volume of recharge, and the well-developed karst system of the region has a very high hydraulic conductivity. Résumé. Le modèle conceptuel classique de l'aquifère karstique libre de la péninsule du Yucatan (Mexique) consiste en une lentille d'eau douce flottant sur une eau salée plus dense qui pénètre à plus de 40 km à l'intérieur des terres. La transmissivité de l'aquifère est très élevée, en sorte que le gradient hydraulique est très faible, compris entre 7 et 10 mm/km dans la plus grande partie du nord de la péninsule. Le modèle AQUIFER a été utilisé pour explorer les écoulements souterrains régionaux dans cet

  2. Tree ring anatomical variability as an indicator for large-magnitude spring flooding in the Lower Mississippi Basin

    NASA Astrophysics Data System (ADS)

    Therrell, M. D.; Meko, M. D.; Bialecki, M.; Harley, G. L.

    2015-12-01

    Predicting the magnitude and frequency of floods relies on instrumental measurements of flood stage and discharge, however instrumental observations prior to the late-nineteenth century are rare. Using paleoproxies such as tree rings to study floods that occurred before the instrumental record, can help provide context for the modern flood record especially the variability of flood recurrence patterns. Riparian trees growing on flooded sites often record flood events as inter- and intra-annual variability in size, shape and arrangement of vessels in the annual xylem growth increment. In this study, we used anomalous anatomical features as well as a modified measure of earlywood (EW) vessel width of oak (Quercus sp.) annual tree rings to identify large-magnitude spring-season flood events at three locations in the Lower Mississippi River (LMR) basin for the past ~300 years. We compared the flood-ring anomaly and EW chronologies with daily river stage height data at several locations and these comparisons indicate that our new flood ring records can individually and jointly explain significant amounts of the variance in both stage height and number of days in flood during spring flood events. Our analyses indicate that our chronologies are recording nearly all large observed LMR floods in the 20th century, and provide a new record of similar events in the 18th and 19th centuries. These results suggest that tree-rings can be effectively used to develop and improve pre-instrumental flood records throughout the LMW region and potentially other similar systems.

  3. Transport of suspended solids from a karstic to an alluvial aquifer: The role of the karst/alluvium interface

    USGS Publications Warehouse

    Massei, N.; Lacroix, M.; Wang, H.Q.; Mahler, B.J.; Dupont, J.P.

    2002-01-01

    This study focuses on the coupled transport of dissolved constituents and particulates, from their infiltration on a karst plateau to their discharge from a karst spring and their arrival at a well in an alluvial plain. Particulate markers were identified and the transport of solids was characterised in situ in porous and karstic media, based on particle size analyses, SEM, and traces. Transport from the sinkhole to the spring appeared to be dominated by flow through karst: particulate transport was apparently conservative between the two sites, and there was little difference in the overall character of the particle size distribution of the particulates infiltrating the sinkhole and of those discharging from the spring. Qualitatively, the mineralogy of the infiltrating and discharging material was similar, although at the spring an autochthonous contribution from the aquifer was noted (chalk particles eroded from the parent rock by weathering). In contrast, transport between the spring and the well appears to be affected by the overlying alluvium: particles in the water from the well, showed evidence of considerable size-sorting. Additionally, SEM images of the well samples showed the presence of particles originating from the overlying alluvial system; these particles were not found in samples from the sinkhole or the spring. The differences between the particulates discharging from the spring and the well indicate that the water pumped from the alluvial plain is coming from the karst aquifer via the very transmissive, complex geologic interface between the underlying chalk formation and the gravel at the base of the overlying alluvial system. ?? 2002 Elsevier Science B.V. All rights reserved.

  4. Paleokarstic and karstic features: Arbuckle and Hunton Groups, Oklahoma

    SciTech Connect

    Al-Shaieb, Z.; Puckette, J.; Matthews, F. . School of Geology); Lynch, M. )

    1993-02-01

    Cores of the Ordovician-age Arbuckle Group and Ordovician-Silurian-Devonian-age Hunton Group contain evidence of paleokarst. Arbuckle and Hunton Group rocks display surprisingly similar suites of distinct paleo-karstic features. Vugs, solution-enlarged fractures, cavities, collapse breccias, and sediment-filled solution features are evident. Phreatic cements are more commonly observed than vadose cements, while primary speleothemic precipitates are rare. A complex history of exposure, subsidence, and diagenesis is recorded in these rocks. Hunton and Arbuckle carbonates have been subaerially exposed for periods of variable intensity and duration during geologic history. Paleokarst appears to have developed subjacent to disconformities within and between formations of the Arbuckle Group and where these rocks subcrop below regional unconformities. Hunton paleokarstic horizons are apparent below the regional pre-Woodford unconformity, while evidence of inter- and intra-formational subaerial exposure is tenuous. This complex hierarchy of unconformities can produce numerous porous horizons. Porosity preservation may depend on subsidence rates or sea level rises rapid enough to prevent extensive low-temperature phreatic cementation and sediment infill of the existing pore network. Caves in the Arbuckle Group in Murray County, Oklahoma contain many karstic features similar to those observed in cores. Cemented collapse breccia and sediment-filled solution cavities are evident in caves developed in the Cool Creek Formation. These caves are part of an extensive internal drainage system associated with Honey Creek near the crest of the Arbuckle anticline. Cave speleothems and surficial travertine deposits are by-product of karstification processes.

  5. Damage caused by long-term, gradual karstic subsidence

    SciTech Connect

    Beck, B.F.; Jenkins, D.T.; Parker, J.W.

    1985-01-01

    Damage due to karstic subsidence (sinkhole collapse) is generally presumed to be relatively rapid in human terms. However, during repaving of a runway apron at Mac Dill Air Force Base, Tampa, Florida, 41 shallow depressions were formed during proof rolling. The apron is underlain by 6-10 m of sand and clayey sand over the limestones of the Floridan Aquifer, which are known for their karst. The apron was originally paved in 1952. Ground penetrating radar revealed that a radar-reflecting boundary, circa 4-5 m below the surface, had also subsided in an inverted-conical pattern beneath the depressions, as well as in other areas. Beneath some of the areas the pavement subbase had also subsided similarly. VLF surveys over and around the depressions mapped a linear trend identical to the apparent alignment of the depressions. Close-spaced drilling confirmed that the subsidence was directly over a depression in the limestone surface. Further, the overlying sand had an N = 0-1, whereas the surrounding sand tested N = 4-6. The authors have concluded that gradual erosion of the overlying sand into karstic depressions and voids in the limestone over a 32 year period has reduced the sand density and strength and caused subsidence where the overlying pavement was loaded.

  6. Rapid formation of large aggregates during the spring bloom of Kerguelen Island: observations and model comparisons

    NASA Astrophysics Data System (ADS)

    Jouandet, M.-P.; Jackson, G. A.; Carlotti, F.; Picheral, M.; Stemmann, L.; Blain, S.

    2014-08-01

    While production of aggregates and their subsequent sinking is known to be one pathway for the downward movement of organic matter from the euphotic zone, the rapid transition from non-aggregated to aggregated particles has not been reported previously. We made one vertical profile of particle size distributions (PSD; sizes ranging from 0.052 to several millimeters in equivalent spherical diameter) at pre-bloom stage and seven vertical profiles 3 weeks later over a 48 h period at early bloom stage using the Underwater Vision Profiler during the Kerguelen Ocean and Plateau Compared Study cruise 2 (KEOPS2, October-November 2011). In these naturally iron-fertilized waters southeast of Kerguelen Island (Southern Ocean), the total particle numerical abundance increased by more than fourfold within this time period. A massive total volume increase associated with particle size distribution changes was observed over the 48 h survey, showing the rapid formation of large particles and their accumulation at the base of the mixed layer. The results of a one-dimensional particle dynamics model support coagulation as the mechanism responsible for the rapid aggregate formation and the development of the VT subsurface maxima. The comparison of VT profiles between early bloom stage and pre-bloom stage indicates an increase of particulate export below 200 m when bloom has developed. These results highlight the role of coagulation in forming large particles and triggering carbon export at the early stage of a naturally iron-fertilized bloom, while zooplankton grazing may dominate later in the season. The rapid changes observed illustrate the critical need to measure carbon export flux with high sampling temporal resolution. Our results are the first published in situ observations of the rapid accumulation of marine aggregates and their export and the general agreement of this rapid event with a model of phytoplankton growth and coagulation.

  7. Investigation of freshwater sponges spicules deposits in a karstic lake in Brazil.

    PubMed

    Machado, V S; Volkmer-Ribeiro, C; Iannuzzi, R

    2016-02-01

    The environmental conditions which contributed to the formation of the notorious quaternary deposits of freshwater sponge spicules in karstic lentic environments in Brazil have been subject of some speculation. No investigation has yet been conducted to test whether these deposits currently originate in karstic lakes. To provide for such an investigation, Serra Negra Lake, which is formed on an ultramafic-alkaline-carbonatite dome at central western Brazil, close to the area of occurrence of the paleo-deposits was selected for the study. Bottom sediments were sampled at 10 stations across the lake, and water was sampled at five of the stations, in June/2011 (rainy season) and October/2011 (dry season). Analysis of granulometry, organic matter and presence of spicules were carried out in the sediments. Lake water was analysed for the main physical and chemical characteristics. Deposit of spicules was restricted to the northern area of the lake, which is rich in macrophyte. The taxonomic analysis of the spicules indicated the contribution of five sponge species, Dosilia pydanieli, Metania spinata, Radiospongilla amazonensis, Trochospongilla variabilis and Heterorotula fistula, which formed large deposits in neighbouring areas. The high silica concentration, derived from the dome volcanic rocks, constant water level and available substrate are credited for the continuous production of sponges and spicules, confirmed by the rare presence of gemmoscleres. The lake is classed as a minerotrophic fen type of bog with a heavy contribution from the surrounding creeks. Lake sediments are fine with high levels of organic matter and peat, which contributed to the trapping of spicules in the sediments. PMID:26909621

  8. CONSTRAINING THE DUST COMA PROPERTIES OF COMET C/SIDING SPRING (2013 A1) AT LARGE HELIOCENTRIC DISTANCES

    SciTech Connect

    Li, Jian-Yang; Samarasinha, Nalin H.; Kelley, Michael S. P.; Farnham, Tony L.; A'Hearn, Michael F.; Mutchler, Max J.; Lisse, Carey M.; Delamere, W. Alan E-mail: nalin@psi.edu E-mail: farnham@astro.umd.edu E-mail: mutchler@stsci.edu E-mail: alan@delamere.biz

    2014-12-10

    The close encounter of comet C/2013 A1 (Siding Spring) with Mars on 2014 October 19 presented an extremely rare opportunity to obtain the first flyby quality data of the nucleus and inner coma of a dynamically new comet. However, the comet's dust tail potentially posed an impact hazard to those spacecraft orbiting Mars. To characterize the comet at large heliocentric distances, study its long-term evolution, and provide critical inputs to hazard modeling, we imaged C/Siding Spring with the Hubble Space Telescope when the comet was at 4.58, 3.77, and 3.28 AU from the Sun. The dust production rate, parameterized by the quantity Afρ, was 2500, 2100, and 1700 cm (5000 km radius aperture) for the three epochs, respectively. The color of the dust coma is (5.0 ± 0.3)%/100 nm for the first two epochs, and (9.0 ± 0.3)%/100 nm for the last epoch, and reddens with increasing cometocentric distance out to ∼3000 km from the nucleus. The spatial distribution and the temporal evolution of the dust color are most consistent with the existence of icy grains in the coma. Two jet-like dust features appear in the northwest and south-southeast directions projected in the sky plane. Within each epoch of 1-2 hr, no temporal variations were observed for either feature, but the position angle of the south-southeastern feature varied between the three epochs by ∼30°. The dust feature morphology suggests two possible orientations for the rotational pole of the nucleus, (R.A., decl.) = (295° ± 5°, +43° ± 2°) and (190° ± 10°, +50° ± 5°), or their diametrically opposite orientations.

  9. Carbonate sedimentation and effects of eutrophication observed at the Kališta subaquatic springs in Lake Ohrid (Macedonia)

    NASA Astrophysics Data System (ADS)

    Matter, M.; Anselmetti, F. S.; Jordanoska, B.; Wagner, B.; Wessels, M.; Wüest, A.

    2010-06-01

    To date, little is known about the role of spring waters with respect to authigenic carbonate precipitation in the shallow lacustrine setting. Lake Ohrid, located in Southeastern Europe, is a large lake fed to over 50% by karstic springs of which half enter subaquatically and influence significantly its ecology and species distribution. In order to evaluate how sedimentological processes are influenced by such shallow-water springs, the Kališta subaquatic spring area in the north west of Lake Ohrid was investigated by a sidescan sonar survey and with sediment traps and three transects of gravity short cores. Results indicate that sedimentation in the spring area is dominated by authigenic carbonate precipitation. High sedimentation rates and evidences for bio-induced precipitation processes were observed in the water column and in the sediments. Two distinct stratigraphic units characterize the shallow subsurface, both composed of carbonate silts with high carbonate contents of up to 96%, but differing in color, carbonate content and diatom content. A chronological correlation of the cores by radiocarbon dates and 137Cs activities places the transition between the two stratigraphic units after ~1955 AD. At that time, coastal sedimentation changed drastically to significantly darker sediments with higher contents of organic matter and more abundant diatoms. This change coincides with the recent human impact of littoral eutrophication.

  10. Carbonate sedimentation and effects of eutrophication observed at the Kališta subaquatic springs in Lake Ohrid (Macedonia)

    NASA Astrophysics Data System (ADS)

    Matter, M.; Anselmetti, F. S.; Jordanoska, B.; Wagner, B.; Wessels, M.; Wüest, A.

    2010-11-01

    To date, little is known about the role of spring waters with respect to authigenic carbonate precipitation in a shallow lacustrine setting. Lake Ohrid, located in Southeastern Europe, is a large lake fed to over 50% by karstic springs of which half enter subaquatically and influence significantly its ecology and species distribution. In order to evaluate how sedimentological processes are influenced by such shallow-water springs, the Kališta subaquatic spring area in the north west of Lake Ohrid was investigated by a sidescan sonar survey and with sediment traps and three transects of gravity short cores. Results indicate that sedimentation in the spring area is dominated by authigenic carbonate precipitation. High sedimentation rates and evidences for bio-induced precipitation processes were observed in the water column and in the sediments. Two distinct stratigraphic units characterize the shallow subsurface, both composed of carbonate silts with high carbonate contents of up to 96%, but differing in color, carbonate content and diatom content. A chronological correlation of the cores by radiocarbon dates and 137Cs activities places the transition between the two stratigraphic units after ~1955 AD. At that time, coastal sedimentation changed drastically to significantly darker sediments with higher contents of organic matter and more abundant diatoms. This change coincides with the recent human impact of littoral eutrophication.

  11. Large batch dimensional metrology demonstrated in the example of a LIGA fabricated spring.

    SciTech Connect

    Aigeldinger, Georg; Skala, Dawn M.; Ceremuga, Joseph T.

    2004-04-01

    Deep x-ray lithography in combination with electroforming is capable of producing high precision metal parts in small lot series. This study deals with a high aspect ratio structure with overall dimensions on the order of 10 mm x 7 mm x 1.5 mm, with the smallest line width being 150 {micro}m. The lateral deviation from the design is to be kept to a minimum, preferably below 5 {micro}m. To ensure adequate quality control, a semi-automated metrology technique has been established to measure all parts. While the paper will give a brief overview of all involved techniques, it focuses on the method to measure the top and bottom of the parts and the top of geometries following the process. The instrument used is a View Engineering Voyager V6x12 microscope, which is fully programmable. The microscope allows direct measurement of geometries but also is capable of saving all captured data as point clouds. These point clouds play a central role when evaluating part geometry. After measuring the part, the point cloud is compared to the computer aided design (CAD) contour of the part, using a commercially available software package. The challenge of proper edge lighting on a nickel alloy part is evaluated by varying lighting conditions systematically. Results of two conditions are presented along with a set of optimized parameters. With the introduced set of tools, process flow can be monitored by measuring geometries, e.g. linewidths in every step of the process line. An example for such analysis is given. After delivery of a large batch of parts, extensive numbers of datasets were available allowing the evaluation of the variation of part geometries. Discussed in detail is the deviation from part top to part bottom geometries indicating swelling of the PMMA mold in the electroplating bath.

  12. In Situ Gene Expression Responsible for Sulfide Oxidation and CO2 Fixation of an Uncultured Large Sausage-Shaped Aquificae Bacterium in a Sulfidic Hot Spring.

    PubMed

    Tamazawa, Satoshi; Yamamoto, Kyosuke; Takasaki, Kazuto; Mitani, Yasuo; Hanada, Satoshi; Kamagata, Yoichi; Tamaki, Hideyuki

    2016-06-25

    We investigated the in situ gene expression profile of sulfur-turf microbial mats dominated by an uncultured large sausage-shaped Aquificae bacterium, a key metabolic player in sulfur-turfs in sulfidic hot springs. A reverse transcription-PCR analysis revealed that the genes responsible for sulfide, sulfite, and thiosulfate oxidation and carbon fixation via the reductive TCA cycle were continuously expressed in sulfur-turf mats taken at different sampling points, seasons, and years. These results suggest that the uncultured large sausage-shaped bacterium has the ability to grow chemolithoautotrophically and plays key roles as a primary producer in the sulfidic hot spring ecosystem in situ. PMID:27297893

  13. In Situ Gene Expression Responsible for Sulfide Oxidation and CO2 Fixation of an Uncultured Large Sausage-Shaped Aquificae Bacterium in a Sulfidic Hot Spring

    PubMed Central

    Tamazawa, Satoshi; Yamamoto, Kyosuke; Takasaki, Kazuto; Mitani, Yasuo; Hanada, Satoshi; Kamagata, Yoichi; Tamaki, Hideyuki

    2016-01-01

    We investigated the in situ gene expression profile of sulfur-turf microbial mats dominated by an uncultured large sausage-shaped Aquificae bacterium, a key metabolic player in sulfur-turfs in sulfidic hot springs. A reverse transcription-PCR analysis revealed that the genes responsible for sulfide, sulfite, and thiosulfate oxidation and carbon fixation via the reductive TCA cycle were continuously expressed in sulfur-turf mats taken at different sampling points, seasons, and years. These results suggest that the uncultured large sausage-shaped bacterium has the ability to grow chemolithoautotrophically and plays key roles as a primary producer in the sulfidic hot spring ecosystem in situ. PMID:27297893

  14. Characterization of mean transit time at large springs in the Upper Colorado River Basin, USA: a tool for assessing groundwater discharge vulnerability

    NASA Astrophysics Data System (ADS)

    Solder, John E.; Stolp, Bernard J.; Heilweil, Victor M.; Susong, David D.

    2016-07-01

    Environmental tracers (noble gases, tritium, industrial gases, stable isotopes, and radio-carbon) and hydrogeology were interpreted to determine groundwater transit-time distribution and calculate mean transit time (MTT) with lumped parameter modeling at 19 large springs distributed throughout the Upper Colorado River Basin (UCRB), USA. The predictive value of the MTT to evaluate the pattern and timing of groundwater response to hydraulic stress (i.e., vulnerability) is examined by a statistical analysis of MTT, historical spring discharge records, and the Palmer Hydrological Drought Index. MTTs of the springs range from 10 to 15,000 years and 90 % of the cumulative discharge-weighted travel-time distribution falls within the range of 2-10,000 years. Historical variability in discharge was assessed as the ratio of 10-90 % flow-exceedance (R 10/90%) and ranged from 2.8 to 1.1 for select springs with available discharge data. The lag-time (i.e., delay in discharge response to drought conditions) was determined by cross-correlation analysis and ranged from 0.5 to 6 years for the same select springs. Springs with shorter MTTs (<80 years) statistically correlate with larger discharge variations and faster responses to drought, indicating MTT can be used for estimating the relative magnitude and timing of groundwater response. Results indicate that groundwater discharge to streams in the UCRB will likely respond on the order of years to climate variation and increasing groundwater withdrawals.

  15. Combined Use of Water Level in Boreholes and Continuous Gravity Measurements for Hydrological Numerical Modeling: Example of the Durzon Karstic Basin (Larzac, France)

    NASA Astrophysics Data System (ADS)

    Fores, B.; Champollion, C.; Le Moigne, N.; Chery, J.; Jourde, H.; Erik, D.; Vernant, P.

    2014-12-01

    Karstic hydrosystems are highly nonlinear and heterogeneous but they represent one of the main water resources in the Mediterranean area. Neither local measurements in boreholes nor analysis at the spring can take into account the variability of the water storage. Since 10 years, ground-based gravity measurements (absolute FG5 and relative CG5) allow the monitoring of the water storage in heterogeneous hydrosystems at intermediate scale between boreholes (local scale) and spring (global scale). Since threeyears, a geophysical observatory has been setup in the Mediterranean area (on the Durzon karstic basinin the south of France). Water level in boreholes and rainfall from rain gaugesare classical hydrological observations. They arecompleted by evapotranspiration measurements from a flux tower and continuous gravity measurements from the GWR iGrav#002 superconducting gravimeter. The main objective of thisstudy is to modelthe wholedata sets withexplicit numericalmodels. Hydrus-1D software allows explicit modeling of water storage and 1D-flow in variably saturated media. With a stochastic sampling, we find the underground parameters (porosity, permeability) that reproduce the most the different observations (gravity, water level, evapotranspiration and rainfall). From the results of the modeling, we discuss the size of the area observed by each type of measurements. Furthermore, water storage and transfer variability may be inferred from the synergy of local (boreholes) and more integrative (gravity) measurements. This study shows the potential of gravity measurements at aquifer scale.

  16. An Analysis of Student Success Rates for Academic and Workforce Programs at a Large Texas Community College: Examining Fall 2009 to Spring 2011

    ERIC Educational Resources Information Center

    High, Clennis F.

    2012-01-01

    Student success rates for academic track and workforce track students were examined for thousands of students at a large urban Texas Community College. The study covered fall 2009 through spring 2011, a two year period. Data were collected from the institution's data base regarding students who successfully completed the courses in which they were…

  17. Hydro-geophysical observations integration in numerical model: case study in Mediterranean karstic unsaturated zone (Larzac, france)

    NASA Astrophysics Data System (ADS)

    Champollion, Cédric; Fores, Benjamin; Le Moigne, Nicolas; Chéry, Jean

    2016-04-01

    Karstic hydro-systems are highly non-linear and heterogeneous but one of the main water resource in the Mediterranean area. Neither local measurements in boreholes or analysis at the spring can take into account the variability of the water storage. Since a few years, ground-based geophysical measurements (such as gravity, electrical resistivity or seismological data) allows following water storage in heterogeneous hydrosystems at an intermediate scale between boreholes and basin. Behind classical rigorous monitoring, the integration of geophysical data in hydrological numerical models in needed for both processes interpretation and quantification. Since a few years, a karstic geophysical observatory (GEK: Géodésie de l'Environnement Karstique, OSU OREME, SNO H+) has been setup in the Mediterranean area in the south of France. The observatory is surrounding more than 250m karstified dolomite, with an unsaturated zone of ~150m thickness. At the observatory water level in boreholes, evapotranspiration and rainfall are classical hydro-meteorological observations completed by continuous gravity, resistivity and seismological measurements. The main objective of the study is the modelling of the whole observation dataset by explicit unsaturated numerical model in one dimension. Hydrus software is used for the explicit modelling of the water storage and transfer and links the different observations (geophysics, water level, evapotranspiration) with the water saturation. Unknown hydrological parameters (permeability, porosity) are retrieved from stochastic inversions. The scale of investigation of the different observations are discussed thank to the modelling results. A sensibility study of the measurements against the model is done and key hydro-geological processes of the site are presented.

  18. Jet-Suspended, Calcite-Ballasted Cyanobacterial Waterwarts in a Desert Spring

    NASA Technical Reports Server (NTRS)

    Pichel-Garcia, Ferran; Wade, Bman D.; Farmer, Jack D.

    2002-01-01

    We describe a population of colonial cyanobacteria (waterwarts) that develops as the dominant primary producer in a bottom-fed, warm spring in the Cuatro Cienegas karstic region of the Mexican Chihuahuan Desert. The centimeter-sized waterwarts were suspended within a central, conically shaped, 6-m deep well by upwelling waters. Waterwarts were built by an unicellular cyanobacterium and supported a community of epiphytic filamentous cyanobacteria and diatoms but were free of heterotrophic bacteria inside. Sequence analysis of genes revealed that this cyanobacterium is only distantly related to several strains of other unicellular teria Cyanothece, Waterwarts contained orderly arrangements of mineral made up of microcrystalline low-magnesium calcite with high levels of strontium and sulfur. Waterwarts were 95.9% (v/v) glycan, 2.8% cells, and 1.3% mineral grains and had a buoyant density of 1.034 kg/L. An analysis of the hydrological properties of the spring well and the waterwarts demonstrated that both large colony size and the presence of controlled amounts of mineral ballast are required to prevent the population from being washed out of the well. The unique hydrological characteristics of the spring have likely selected for both traits. The mechanisms by which controlled nucleation of extracellular calcite is achieved remain to be explored.

  19. Geodesic and hydrogeophysic long term observations in the Durzon karstic aquifer (Larzac, France)

    NASA Astrophysics Data System (ADS)

    Le Moigne, Nicolas; Bayer, Roger; Boudin, Frederick; Champollion, Cedric; Chery, Jean; Collard, Philippe; Daignières, Marc; Deville, Sabrina; Doerflinger, Erik; Vernant, Philippe

    2010-05-01

    Karsts are generally characterized by high heterogeneity at all scales for both the water storage properties and the mode of water transport. The Durzon karst system is located in south of France and is characterized by a unsaturated zone of 100-150 m width. The water input is exclusively rainfall and draining occurs at the Durzon perennial spring in a karstic valley. The Durzon aquifer has been monitored by our group by different geophysical methods (gravimetry, tiltmetry, more details below) for several years. The present-day stage of the project is to setup long term observations to assess hydrological properties of the karst in a small area of 500m*500m with numerous caves (up to 100 m deep and more than 2 km of development). The observations are of four major types: - Continuous high frequency and high accuracy gravimetry: Gravimetric observations can be directly linked to the variations of water masses in the unsaturated zone. The iGrav™ Superconducting Gravity Meter from GWR (San Diego, USA) will be used to record continuous gravity variations and track water mass variations at a few millimeters level. The iGrav™ is a new SG model from GWR that has been simplified for portable and field operation, but retains the stability and precision of previous SGs. With a drift rate of less than 0.5 microGal/month and a virtually constant scale factory, the iGrav™ will provide a much higher stability and precision than can be achieved with mechanical spring-type gravity meters. - Water flux measurements (atmospheric and in-situ): A flux tower provides evapo-transpiration measurements (output) allowing complete budget calculation with the help of gravity (storage variations) and rainfall (input). An original measurement corresponds to the measure of the in-situ flow inside karstic caves (stalactites and underground river). - Tiltmetry: In situ (in caves) measurements are completed by long base silica tiltmeters. Tiltmeters are sensible to water storage in fractures

  20. Characterization of mean transit time at large springs in the Upper Colorado River Basin, USA: A tool for assessing groundwater discharge vulnerability

    USGS Publications Warehouse

    Solder, John; Stolp, Bernard J.; Heilweil, Victor M.; Susong, David D.

    2016-01-01

    Environmental tracers (noble gases, tritium, industrial gases, stable isotopes, and radio-carbon) and hydrogeology were interpreted to determine groundwater transit-time distribution and calculate mean transit time (MTT) with lumped parameter modeling at 19 large springs distributed throughout the Upper Colorado River Basin (UCRB), USA. The predictive value of the MTT to evaluate the pattern and timing of groundwater response to hydraulic stress (i.e., vulnerability) is examined by a statistical analysis of MTT, historical spring discharge records, and the Palmer Hydrological Drought Index. MTTs of the springs range from 10 to 15,000 years and 90 % of the cumulative discharge-weighted travel-time distribution falls within the range of 2−10,000 years. Historical variability in discharge was assessed as the ratio of 10–90 % flow-exceedance (R 10/90%) and ranged from 2.8 to 1.1 for select springs with available discharge data. The lag-time (i.e., delay in discharge response to drought conditions) was determined by cross-correlation analysis and ranged from 0.5 to 6 years for the same select springs. Springs with shorter MTTs (<80 years) statistically correlate with larger discharge variations and faster responses to drought, indicating MTT can be used for estimating the relative magnitude and timing of groundwater response. Results indicate that groundwater discharge to streams in the UCRB will likely respond on the order of years to climate variation and increasing groundwater withdrawals.

  1. Correlation of the Peach Springs Tuff, a large-volume Miocene ignimbrite sheet in California and Arizona ( USA).

    USGS Publications Warehouse

    Glazner, A.F.; Nielson, J.E.; Howard, K.A.; Miller, D.M.

    1986-01-01

    The Peach Springs Tuff is a distinctive early Miocene ignimbrite deposit that was first recognized in western Arizona. Recent field studies and phenocryst analyses indicate that adjacent outcrops of similar tuff in the central and eastern Mojave Desert may be correlative. This proposed correlation implies that outcrops of the tuff are scattered over an area of at least 35 000 km2 from the western Colorado Plateau to Barstow, California, and that the erupted volume, allowing for posteruption crustal extension, was at least several hundred cubic kilometres. Thus, the Peach Springs Tuff may be a regional stratigraphic marker, useful for determining regional paleogeography and the time and extent of Tertiary crustal extension. -Authors

  2. From Newton's Second Law to Huygens's Principle: Visualizing Waves in a Large Array of Masses Joined by Springs

    ERIC Educational Resources Information Center

    Dolinko, A. E.

    2009-01-01

    By simulating the dynamics of a bidimensional array of springs and masses, the propagation of conveniently generated waves is visualized. The simulation is exclusively based on Newton's second law and was made to provide insight into the physics of wave propagation. By controlling parameters such as the magnitude of the mass and the elastic…

  3. A new approach to model the variability of karstic recharge

    NASA Astrophysics Data System (ADS)

    Hartmann, A.; Lange, J.; Weiler, M.; Arbel, Y.; Greenbaum, N.

    2012-02-01

    In karst systems, surface near dissolution carbonate rock results in a high spatial and temporal variability of groundwater recharge. To adequately represent the dominating recharge processes in hydrological models is still a challenge, especially in data scare regions. In this study, we developed a recharge model that is based on a perceptual model of the epikarst. It represents epikarst heterogeneity as a set of system property distributions to produce not only a single recharge time series, but a variety of time series representing the spatial recharge variability. We tested the new model with a unique set of spatially distributed flow and tracer observations in a karstic cave at Mt. Carmel, Israel. We transformed the spatial variability into statistical variables and apply an iterative calibration strategy in which more and more data was added to the calibration. Thereby, we could show that the model is only able to produce realistic results when the information about the spatial variability of the observations was included into the model calibration. We could also show that tracer information improves the model performance if data about the variability is not included.

  4. Estimating Preferential Flow in Karstic Aquifers Using Statistical Mixed Models

    PubMed Central

    Anaya, Angel A.; Padilla, Ingrid; Macchiavelli, Raul; Vesper, Dorothy J.; Meeker, John D.; Alshawabkeh, Akram N.

    2013-01-01

    Karst aquifers are highly productive groundwater systems often associated with conduit flow. These systems can be highly vulnerable to contamination, resulting in a high potential for contaminant exposure to humans and ecosystems. This work develops statistical models to spatially characterize flow and transport patterns in karstified limestone and determines the effect of aquifer flow rates on these patterns. A laboratory-scale Geo-HydroBed model is used to simulate flow and transport processes in a karstic limestone unit. The model consists of stainless-steel tanks containing a karstified limestone block collected from a karst aquifer formation in northern Puerto Rico. Experimental work involves making a series of flow and tracer injections, while monitoring hydraulic and tracer response spatially and temporally. Statistical mixed models are applied to hydraulic data to determine likely pathways of preferential flow in the limestone units. The models indicate a highly heterogeneous system with dominant, flow-dependent preferential flow regions. Results indicate that regions of preferential flow tend to expand at higher groundwater flow rates, suggesting a greater volume of the system being flushed by flowing water at higher rates. Spatial and temporal distribution of tracer concentrations indicates the presence of conduit-like and diffuse flow transport in the system, supporting the notion of both combined transport mechanisms in the limestone unit. The temporal response of tracer concentrations at different locations in the model coincide with, and confirms the preferential flow distribution generated with the statistical mixed models used in the study. PMID:23802921

  5. The submarine river of Port Miou (France), A karstic system inherited from the Messinian deep stage

    NASA Astrophysics Data System (ADS)

    Cavalera, T.; Gilli, E.

    2009-04-01

    , upstream of the dam and at the end of the cave. The presence of heavy metals in the sediments of the Port Miou gallery is explained as resulting from the suction of residues of bauxite treatments, rejected in the nearby Cassidaigne deep-sea canyon at a depth of 300 m bsl. This residual product locally called "red mud" is very rich in titanium. The saline contamination of Port Miou could be carried out by a seawater inflow through a deep karstic conduit connected to the canyon of Cassidaigne. A long term monitoring of the springs, indicates that the system is contaminated by a permanent sweater inflow close to 500 l.s-1. A laboratory model has been realized that simulates perfectly the functioning.

  6. Deep Production Well for Geothermal Direct-Use Heating of A Large Commercial Greenhouse, Radium Springs, Rio Grande Rift, New Mexico

    SciTech Connect

    James C. Witcher

    2002-01-02

    Expansion of a large commercial geothermally-heated greenhouse is underway and requires additional geothermal fluid production. This report discusses the results of a cost-shared U.S. Department of Energy (DOE) and A.R. Masson, Inc. drilling project designed to construct a highly productive geothermal production well for expansion of the large commercial greenhouse at Radium Springs. The well should eliminate the potential for future thermal breakthrough from existing injection wells and the inducement of inflow from shallow cold water aquifers by geothermal production drawdown in the shallow reservoir. An 800 feet deep production well, Masson 36, was drilled on a US Bureau of Land Management (BLM) Geothermal Lease NM-3479 at Radium Springs adjacent to the A. R. Masson Radium Springs Farm commercial greenhouse 15 miles north of Las Cruces in Dona Ana County, New Mexico just west of Interstate 25 near the east bank of the Rio Grande. The area is in the Rio Grande rift, a tectonically-active region with high heat flow, and is one of the major geothermal provinces in the western United State.

  7. Introduction of wavelet analyses to rainfall/runoffs relationship for a karstic basin: the case of Licq-Atherey karstic system (France).

    PubMed

    Labat, D; Ababou, R; Mangin, A

    2001-01-01

    Karstic systems are highly heterogeneous geological formations characterized by a multiscale temporal and spatial hydrologic behavior with more or less localized temporal and spatial structures. Classical correlation and spectral analyses cannot take into account these properties. Therefore, it is proposed to introduce a new kind of transformation: the wavelet transform. Here we focus particularly on the use of wavelets to study temporal behavior of local precipitation and watershed runoffs from a part of the karstic system. In the first part of the paper, a brief mathematical overview of the continuous Morlet wavelet transform and of the multiresolution analysis is presented. An analogy with spectral analyses allows the introduction of concepts such as wavelet spectrum and cross-spectrum. In the second part, classical methods (spectral and correlation analyses) and wavelet transforms are applied and compared for daily rainfall rates and runoffs measured on a French karstic watershed (Pyrénées) over a period of 30 years. Different characteristic time scales of the rainfall and runoff processes are determined. These time scales are typically on the order of a few days for floods, but they also include significant half-year and one-year components and multi-annual components. The multiresolution cross-analysis also provides a new interpretation of the impulse response of the system. To conclude, wavelet transforms provide a valuable amount of information, which may be now taken into account in both temporal and spatially distributed karst modeling of precipitation and runoff. PMID:11447860

  8. Variability of atmospheric greenhouse gases as a biogeochemical processing signal at regional scale in a karstic ecosystem

    NASA Astrophysics Data System (ADS)

    Borràs, Sílvia; Vazquez, Eusebi; Morguí, Josep-Anton; Àgueda, Alba; Batet, Oscar; Cañas, Lídia; Curcoll, Roger; Grossi, Claudia; Nofuentes, Manel; Occhipinti, Paola; Rodó, Xavier

    2015-04-01

    The South-eastern area of the Iberian Peninsula is an area where climatic conditions reach extreme climatic conditions during the year, and is also heavily affected by the ENSO and NAO. The Natural Park of Cazorla, Segura de la Sierra and Las Villas is located in this region, and it is the largest protected natural area in Spain (209920 Ha). This area is characterized by important climatic and hydrologic contrasts: although the mean annual precipitation is 770 nm, the karstic soils are the main cause for water scarcity during the summer months, while on the other hand it is in this area where the two main rivers of Southern Spain, the Segura and the Guadalquivir, are born. The protected area comprises many forested landscapes, karstic areas and reservoirs like Tranco de Beas. The temperatures during summer are high, with over 40°C heatwaves occurring each year. But during the winter months, the land surface can be covered by snow for periods of time up until 30 days. The ENSO and NAO influences cause also an important inter annual climatic variability in this area. Under the ENSO, autumnal periods are more humid while the following spring is drier. In this area vegetal Mediterranean communities are dominant. But there are also a high number of endemic species and derelict species typical of temperate climate. Therefore it is a protected area with high specific diversity. Additionally, there is an important agricultural activity in the fringe areas of the Natural Park, mainly for olive production, while inside the Park this activity is focused on mountain wheat production. Therefore the diverse vegetal communities and landscapes can easily be under extreme climatic pressures, affecting in turn the biogeochemical processes at the regional scale. The constant, high-frequency monitoring of greenhouse gases (GHG) (CO2 and CH4) integrates the biogeochemical signal of changes in this area related to the carbon cycle at the regional scale, capturing the high diversity of

  9. Automatic detection of karstic sinkholes in seismic 3D images using circular Hough transform

    NASA Astrophysics Data System (ADS)

    Heydari Parchkoohi, Mostafa; Keshavarz Farajkhah, Nasser; Salimi Delshad, Meysam

    2015-10-01

    More than 30% of hydrocarbon reservoirs are reported in carbonates that mostly include evidence of fractures and karstification. Generally, the detection of karstic sinkholes prognosticate good quality hydrocarbon reservoirs where looser sediments fill the holes penetrating hard limestone and the overburden pressure on infill sediments is mostly tolerated by their sturdier surrounding structure. They are also useful for the detection of erosional surfaces in seismic stratigraphic studies and imply possible relative sea level fall at the time of establishment. Karstic sinkholes are identified straightforwardly by using seismic geometric attributes (e.g. coherency, curvature) in which lateral variations are much more emphasized with respect to the original 3D seismic image. Then, seismic interpreters rely on their visual skills and experience in detecting roughly round objects in seismic attribute maps. In this paper, we introduce an image processing workflow to enhance selective edges in seismic attribute volumes stemming from karstic sinkholes and finally locate them in a high quality 3D seismic image by using circular Hough transform. Afterwards, we present a case study from an on-shore oilfield in southwest Iran, in which the proposed algorithm is applied and karstic sinkholes are traced.

  10. Carbon stocks of tropical coastal wetlands within the karstic landscape of the Mexican Caribbean.

    PubMed

    Adame, Maria Fernanda; Kauffman, J Boone; Medina, Israel; Gamboa, Julieta N; Torres, Olmo; Caamal, Juan P; Reza, Miriam; Herrera-Silveira, Jorge A

    2013-01-01

    Coastal wetlands can have exceptionally large carbon (C) stocks and their protection and restoration would constitute an effective mitigation strategy to climate change. Inclusion of coastal ecosystems in mitigation strategies requires quantification of carbon stocks in order to calculate emissions or sequestration through time. In this study, we quantified the ecosystem C stocks of coastal wetlands of the Sian Ka'an Biosphere Reserve (SKBR) in the Yucatan Peninsula, Mexico. We stratified the SKBR into different vegetation types (tall, medium and dwarf mangroves, and marshes), and examined relationships of environmental variables with C stocks. At nine sites within SKBR, we quantified ecosystem C stocks through measurement of above and belowground biomass, downed wood, and soil C. Additionally, we measured nitrogen (N) and phosphorus (P) from the soil and interstitial salinity. Tall mangroves had the highest C stocks (987±338 Mg ha(-1)) followed by medium mangroves (623±41 Mg ha(-1)), dwarf mangroves (381±52 Mg ha(-1)) and marshes (177±73 Mg ha(-1)). At all sites, soil C comprised the majority of the ecosystem C stocks (78-99%). Highest C stocks were measured in soils that were relatively low in salinity, high in P and low in N∶P, suggesting that P limits C sequestration and accumulation potential. In this karstic area, coastal wetlands, especially mangroves, are important C stocks. At the landscape scale, the coastal wetlands of Sian Ka'an covering ≈172,176 ha may store 43.2 to 58.0 million Mg of C. PMID:23457583

  11. Carbon Stocks of Tropical Coastal Wetlands within the Karstic Landscape of the Mexican Caribbean

    PubMed Central

    Adame, Maria Fernanda; Kauffman, J. Boone; Medina, Israel; Gamboa, Julieta N.; Torres, Olmo; Caamal, Juan P.; Reza, Miriam; Herrera-Silveira, Jorge A.

    2013-01-01

    Coastal wetlands can have exceptionally large carbon (C) stocks and their protection and restoration would constitute an effective mitigation strategy to climate change. Inclusion of coastal ecosystems in mitigation strategies requires quantification of carbon stocks in order to calculate emissions or sequestration through time. In this study, we quantified the ecosystem C stocks of coastal wetlands of the Sian Ka'an Biosphere Reserve (SKBR) in the Yucatan Peninsula, Mexico. We stratified the SKBR into different vegetation types (tall, medium and dwarf mangroves, and marshes), and examined relationships of environmental variables with C stocks. At nine sites within SKBR, we quantified ecosystem C stocks through measurement of above and belowground biomass, downed wood, and soil C. Additionally, we measured nitrogen (N) and phosphorus (P) from the soil and interstitial salinity. Tall mangroves had the highest C stocks (987±338 Mg ha−1) followed by medium mangroves (623±41 Mg ha−1), dwarf mangroves (381±52 Mg ha−1) and marshes (177±73 Mg ha−1). At all sites, soil C comprised the majority of the ecosystem C stocks (78–99%). Highest C stocks were measured in soils that were relatively low in salinity, high in P and low in N∶P, suggesting that P limits C sequestration and accumulation potential. In this karstic area, coastal wetlands, especially mangroves, are important C stocks. At the landscape scale, the coastal wetlands of Sian Ka'an covering ≈172,176 ha may store 43.2 to 58.0 million Mg of C. PMID:23457583

  12. Groundwater flow cycling between a submarine spring and an inland fresh water spring.

    PubMed

    Davis, J Hal; Verdi, Richard

    2014-01-01

    Spring Creek Springs and Wakulla Springs are large first magnitude springs that derive water from the Upper Floridan Aquifer. The submarine Spring Creek Springs are located in a marine estuary and Wakulla Springs are located 18 km inland. Wakulla Springs has had a consistent increase in flow from the 1930s to the present. This increase is probably due to the rising sea level, which puts additional pressure head on the submarine Spring Creek Springs, reducing its fresh water flow and increasing flows in Wakulla Springs. To improve understanding of the complex relations between these springs, flow and salinity data were collected from June 25, 2007 to June 30, 2010. The flow in Spring Creek Springs was most sensitive to rainfall and salt water intrusion, and the flow in Wakulla Springs was most sensitive to rainfall and the flow in Spring Creek Springs. Flows from the springs were found to be connected, and composed of three repeating phases in a karst spring flow cycle: Phase 1 occurred during low rainfall periods and was characterized by salt water backflow into the Spring Creek Springs caves. The higher density salt water blocked fresh water flow and resulted in a higher equivalent fresh water head in Spring Creek Springs than in Wakulla Springs. The blocked fresh water was diverted to Wakulla Springs, approximately doubling its flow. Phase 2 occurred when heavy rainfall resulted in temporarily high creek flows to nearby sinkholes that purged the salt water from the Spring Creek Springs caves. Phase 3 occurred after streams returned to base flow. The Spring Creek Springs caves retained a lower equivalent fresh water head than Wakulla Springs, causing them to flow large amounts of fresh water while Wakulla Springs flow was reduced by about half. PMID:24138490

  13. Groundwater flow cycling between a submarine spring and an inland fresh water spring

    USGS Publications Warehouse

    Davis, J. Hal; Verdi, Richard

    2014-01-01

    Spring Creek Springs and Wakulla Springs are large first magnitude springs that derive water from the Upper Floridan Aquifer. The submarine Spring Creek Springs are located in a marine estuary and Wakulla Springs are located 18 km inland. Wakulla Springs has had a consistent increase in flow from the 1930s to the present. This increase is probably due to the rising sea level, which puts additional pressure head on the submarine Spring Creek Springs, reducing its fresh water flow and increasing flows in Wakulla Springs. To improve understanding of the complex relations between these springs, flow and salinity data were collected from June 25, 2007 to June 30, 2010. The flow in Spring Creek Springs was most sensitive to rainfall and salt water intrusion, and the flow in Wakulla Springs was most sensitive to rainfall and the flow in Spring Creek Springs. Flows from the springs were found to be connected, and composed of three repeating phases in a karst spring flow cycle: Phase 1 occurred during low rainfall periods and was characterized by salt water backflow into the Spring Creek Springs caves. The higher density salt water blocked fresh water flow and resulted in a higher equivalent fresh water head in Spring Creek Springs than in Wakulla Springs. The blocked fresh water was diverted to Wakulla Springs, approximately doubling its flow. Phase 2 occurred when heavy rainfall resulted in temporarily high creek flows to nearby sinkholes that purged the salt water from the Spring Creek Springs caves. Phase 3 occurred after streams returned to base flow. The Spring Creek Springs caves retained a lower equivalent fresh water head than Wakulla Springs, causing them to flow large amounts of fresh water while Wakulla Springs flow was reduced by about half.

  14. Organic matter dynamics in a karstic watershed: Example from Santa Fe River, Florida, USA

    NASA Astrophysics Data System (ADS)

    Jin, J.; Khadka, M. B.; Martin, J. B.; Zimmerman, A. R.

    2011-12-01

    Organic matter (OM) dynamics in karstic watersheds can involve a range of interactions between organic and inorganic phases of carbon. These interactions include OM remineralization, which will changes its lability, increase dissolved inorganic carbon (DIC) concentrations, reduce pH, and enhance carbonate mineral dissolution. Dissolved organic carbon (DOC) concentrations are elevated in black-water rivers of northern Florida from both allochthonous and autochthonous sources and these rivers flow into and interact with the karstic Floridan Aquifer. One such river, the Santa Fe River, is split into upper confined and lower unconfined watersheds by the Cody Scarp, which represent the erosional edge of a regional confining unit. Water samples were collected from 8 sites across the entire Santa Fe River watershed (SFRW) during 9 sampling trips from December 2009 to May 2011 at flow conditions that ranged from 27 to 39 m3/s, with the highest flow about 45% higher than baseflow. At sites above the Cody Scarp, the river has elevated DOC concentrations, which decrease downstream, while dissolved inorganic carbon (DIC) and δ13C-DIC show opposite trends. At high flow, DOC concentrations progressively decrease downstream from dilution by low-DOC water discharging from the Floridan Aquifer. At low flow, the water chemistry varies little from upstream to downstream, largely because the composition of upstream water becomes similar to that of downstream water. DOC is inversely and linearly correlated with DIC and δ13C-DIC, but the slope of the correlations vary with discharge, with low flow having more negative slopes than high flow. The OM becomes more labile with distance downstream as assessed using two fluorescence indices, biological/autochthonous index (BIX) and humification index (HIX). This increase in lability suggests that DOC is produced in the river, and this production is reflected in a downstream increase in DOC flux regardless of dilution by the influx of low

  15. Spring Tire

    NASA Technical Reports Server (NTRS)

    Asnani, Vivake M.; Benzing, Jim; Kish, Jim C.

    2011-01-01

    The spring tire is made from helical springs, requires no air or rubber, and consumes nearly zero energy. The tire design provides greater traction in sandy and/or rocky soil, can operate in microgravity and under harsh conditions (vastly varying temperatures), and is non-pneumatic. Like any tire, the spring tire is approximately a toroidal-shaped object intended to be mounted on a transportation wheel. Its basic function is also similar to a traditional tire, in that the spring tire contours to the surface on which it is driven to facilitate traction, and to reduce the transmission of vibration to the vehicle. The essential difference between other tires and the spring tire is the use of helical springs to support and/or distribute load. They are coiled wires that deform elastically under load with little energy loss.

  16. Geodesic variations induced by hydrology on the karstic plateau of Calern (Alpes-Maritimes, France)

    NASA Astrophysics Data System (ADS)

    Gilli, E.; Boudin, F.; Audra, Ph; Florsch, N.

    2009-04-01

    On the karstic plateau of Calern, (Caussols, France) the astronomical observatory of the OCA measures geodetic variations since several years. In order to explore possible relationships with hydrology, two long baseline inclinometers were installed in a shaft and several hydrogeological sites have been instrumented since 2007. Dye tests have shown that, except for its Western third, the plateau is drained towards the East, to the spring of Bramafan. The instrument made it possible to characterize different reservoirs: the deep karst aquifer of Bramafam with high amplitude oscillations of its water table, up to 100 m, the perched aquifer of Moustiques shaft whose response is attenuated, and several slope aquifers with reduced oscillations (Fontaniers, Castel Bon Pré). The correlation with rainfall recorded at the observatory Calern is excellent. The inclinometric observations show a load in the direction N100 ° E which starts one month after the beginning of the rainy period, then an unload in the direction N90 ° E during the dry period. The maximum inclinometric gradient reaches 8 μrad. The best correlation between hydrology and inclinometry is observed for the deep aquifers. The first autumn rainfall is ineffective, then there is a good correlation water table / inclinometers, from November, when heavy rains are associated to inclinometry with a charge towards N100 ° E. The plateau then stabilizes but it starts again to tilt at the end of the dry season. The long term inclinometric variations could therefore be linked to the variations of the water table. In autumn, the first rainfall recharges the epikarst and refills the reserves, that were emptied during the low water. This does not affect the inclinometers. The winter rains cause the water to flush towards the eastern deep aquifer and this provokes a quick tilt of the plateau. Then occasional variations are measured by the N320 inclinometer. A simple model of flexure, based on the principle of Boussinesq

  17. New species of Blaesodactylus (Squamata: Gekkonidae) from Tsingy karstic outcrops in Ankarana National Park, northern Madagascar.

    PubMed

    Jono, Teppei; Bauer, Aaron M; Brennan, Ian; Mori, Akira

    2015-01-01

    We describe a new gecko of the genus Blaesodactylus from a karstic outcrop in deciduous dry forest of Ankarana National Park, northern Madagascar. Blaesodactylus microtuberculatus sp. nov., the fifth recognized species of Blaesodactylus, is distinguished from all other congeners, B. ambonihazo, B. antongilensis, B. boivini and B. sakalava by a combination of small, homogeneous gular granules, unspotted venter and lack of tubercles on distal part of original tail. Mitochondrial (ND2 and ND4) and nuclear (RAG-1) DNA identify a consistent divergence between B. microtuberculatus and its allotopic sister species B. boivini. We highlight habitat partitioning in these allotopic congeners where Blaesodactylus microtuberculatus inhabits karstic outcrops in Tsingy massif, and B. boivini dwells on tree trunks in deciduous dry forest. PMID:26249960

  18. Management of karstic coastal groundwater in a changing environment (Salento, southern Italy)

    NASA Astrophysics Data System (ADS)

    Polemio, Maurizio; Romanazzi, Andrea

    2014-05-01

    Keywords: groundwater management, numerical modelling, MODFLOW, SEAWAT, climate change, coastal karst aquifer We have been witness, during the second half of the 20th century, of an increase of groundwater discharge. Today a great number of aquifers are overexploited in the world. Problems ties to overexploitation, as piezometric decline and increase of seawater intrusion, are so more amplify in the coastal aquifers, and in particular, in karst coastal aquifers. Seawater intrusion, in fact, is a pervasive problem affecting coastal aquifer, where the concentration of population and the increasing water demand creates risks of overexploitation, especially in those areas where is the only resource of drinking and irrigation water. The whole effect could be a groundwater quality and quantity degradation. This is very often the case of coastal karst aquifers of Mediterranean countries. The general purpose of this paper is to prove the capability of large-scale numerical models in management of groundwater, in particular for achieve forecast scenarios to evaluate the impacts of climate change on groundwater resources. Study area is the karst coastal aquifer of Salento (Southern Italy), largely utilized to satisfy the agricultural demand and drinking demand with huge effects in terms of reduced availability and increasing salinity. The computer codes selected for numerical groundwater modelling were MODFLOW and SEAWAT. Groundwater flow modelling is based on the concept of a equivalent homogeneous porous medium. Three forecast transient scenarios, referred to 2001-2020, 2021-2040 and 2041-2060, were implemented, on the basis of calibrated and validated model, with the aim to predicting the evolution of piezometric level and seawater intrusion. The scenarios were discussed considering the effects of climate change, sea level rise and change of sea salinity. Some irrigation discharge scenarios were considered in the discussion . Results shows qualitative and quantitative

  19. Dissolution on Titan and on Earth: Towards the age of Titan's karstic landscapes

    NASA Astrophysics Data System (ADS)

    Cornet, T.; Cordier, D.; Le Bahers, T.; Bourgeois, O.; Fleurant, C.; Le Mouélic, S.; Altobelli, N.

    2015-10-01

    The morphology of Titan's lacustrine depressions led to comparisons with terrestrial depressions developed by karstic dissolution. We tested this hypothesis by computing dissolution rates of Titan's solids in liquid methane. We inferred from these rates the timescales needed to create dissolution landforms of a given depth. Dissolution would be a very efficient geological process to shape Titan's surface, on timescales generally shorter than 100 Myrs, consistent with the youth of Titan's surface (<1 Gyr).

  20. Combining large magnetostriction and large magnetostrictive susceptibility in TbFeCo/Y{sub x}Fe{sub 1-x} exchange-spring-type multilayers

    SciTech Connect

    Huong Giang, D.T.; Duc, N.H.; Thuc, V.N.; Vu, L.V.; Chau, N.

    2004-08-30

    An approach to obtain both large magnetostriction and large magnetostrictive susceptibility is developed. It is applied to sputtered {l_brace}Tb(Fe{sub 0.55}Co{sub 0.45}){sub 1.5}/(Y{sub x}Fe{sub 1-x}){r_brace} (x=0, 0.1 and 0.2) multilayers. In the as-deposited samples, the TbFeCo layers are in the amorphous state, but the microstructure of the Y{sub x}Fe{sub 1-x} layers is not the same: A crystalline state is observed in pure Fe layers (x=0), whereas body-centered-cubic-Fe nanocrystals coexist within an YFe amorphous matrix in Y{sub 0.1}Fe{sub 0.9} layers. A parallel magnetostrictive susceptibility {chi}{sub {lambda}}{sub parallel} as large as 29.4x10{sup -2} T{sup -1}, which is almost half of that (79.6x10{sup -2} T{sup -1}) of the Metglas 2605SC was obtained for x=0.1. This is attributed to the exchange coupling between sandwiched TbFeCo layers and nanostructured YFe layers.

  1. Human Impact on Biogeochemical Cycles and Deposition Dynamics in Karstic Lakes: El Tobar Lake Record (Central Iberian Range, Spain)

    NASA Astrophysics Data System (ADS)

    Barreiro-Lostres, F.; Moreno-Caballud, A.; Giralt, S.; Hillman, A. L.; Brown, E. T.; Abbott, M. B.; Valero-Garces, B. L.

    2014-12-01

    Karstic lakes in the Iberian Range (Central Spain) provide a unique opportunity to test the human impact in the watersheds and the aquatic environments during historical times. We reconstruct the depositional evolution and the changes in biogeochemical cycles of El Tobar karstic lake, evaluating the response and the resilience of this Mediterranean ecosystem to both anthropogenic impacts and climate forcing during the last 1000 years. Lake El Tobar (40°32'N, 3°56'W; 1200 m a.s.l.; see Figure), 16 ha surface area, 20 m max. depth and permanent meromictic conditions, has a relatively large watershed (1080 ha). Five 8 m long sediment cores and short gravity cores where recovered, imaged, logged with a Geotek, described and sampled for geochemical analyses (elemental TOC, TIC, TN, TS), XRF scanner and ICP-MS, and dated (137Cs and 10 14C assays). The record is a combination of: i) laminated dark silts with terrestrial remains and diatoms and ii) massive to banded light silts (mm to cm -thick layers) interpreted as flood deposits. Sediments, TOC, and Br/Ti and Sr/Ca ratios identify four periods of increased sediment delivery occurred about 1500, 1800, 1850 and 1900 AD, coinciding with large land uses changes of regional relevance such as land clearing and increased population. Two main hydrological changes are clearly recorded in El Tobar sequence. The first one, marked by a sharp decrease in Mg, Ca and Si concentrations, took place about 1200 AD, and during a period of increasing lake level, which shifted from shallower to deeper facies and from carbonatic to clastic and organic-rich deposition. This change was likely related to increased water availability synchronous to the transition from the Medieval Climate Anomaly to the Little Ice Age. The second one was a canal construction in 1967 AD when a nearby reservoir provided fresh water influx to the lake, and resulted in stronger meromictic conditions in the system after canal construction, which is marked by lower

  2. An example of application of stochastic model to forecasting karst springs discharge

    NASA Astrophysics Data System (ADS)

    Ristic Vakanjac, V.; Stevanovic, Z.; Milanovic, S.; Vasic, Lj.

    2012-04-01

    The groundwater resources in karst are one of the most significant sources of drinking water supply worldwide. The importance of karst is reflected in the ability of karst massifs to accumulate a certain quantity of water and subsequently release it through karst springs. Therefore, well developed karst could amortize the effects of huge and intensive rainfalls, i.e. these regions could largely reduce the impact of floods and preserve stored water for certain period of time. The extensive use of karst groundwater in water supply systems throughout many countries in SE Europe is due to the wide distribution of karstic areas, the abundant reserves, and its excellent quality. However, because of an unstable flow regime when only natural springflow is tapped, numerous problems arise during the recession period (summer-autumn). A mathematical model that simulates daily discharges of karst springs in the multiannual period was developed at the Department of Hydrogeology of the Faculty of Mining & Geology, Serbia. This model contains several independent levels. Each level performs a specific function, different by their mathematical structure and period of time discretization, with the same final goal to define daily discharge over a certain period. The model was conceived at 5 levels (modules) of different computing functions and purposes (Ristić, 2007): •level 1. - completing the series of available mean monthly discharge by MNC model •level 2. - determining the duration of an appropriate period for evaluation of elements of multiannual water balance of the karst aquifer - INTKR •level 3. - water budget of the karst aquifer - BILANS •level 4. - identifying parameters of transformation functions module - TRANSFUNK •level 5. - simulation of daily discharges for a multi annual period - SIMIST The model is applied on the Mlava Spring, at the northern margin of Beljanica Mt. which is the largest spring of Carpathian Arch in Eastern Serbia. The coefficient of

  3. Hazard connected to railway tunnel construction in karstic area: applied geomorphological and hydrogeological surveys

    NASA Astrophysics Data System (ADS)

    Casagrande, G.; Cucchi, F.; Zini, L.

    2005-02-01

    In a mature karstic system, the realisation of galleries using the methodology of railway tunnel boring machine (TBM) involves particular problems due to the high risk of interference with groundwater (often subject to remarkable level variations) and with cavities and/or thick fill deposits. In order to define groundwater features it is necessary to investigate both hydrodynamic and karstification. To define and quantify the karst phenomenon in the epikarst of the Trieste Karst (Italy), an applied geomorphological approach has been experimented with surface and cavity surveys. The surface surveys have contributed to determining the potential karst versus the different outcropping lithologies and to define the structural setting of the rocky mass also through the realisation of geostructural stations and the survey of the main lines thanks to photo-interpretation. Moreover, all the dolines and the cavities present in the area interested by the gallery have been studied by analysing the probable extension of caves and/or of the secondary fill deposits and by evaluating the different genetic models. In an area 900m large and 27km long, which has been studied because of the underground karst, there are 41 dolines having diameters superior to 100m and 93 dolines whose diameters range between 100 and 50m; the dolines whose diameters are inferior to 50m are 282. The entrances of known and registered cavities in the cadastre records are 520. The hypogeal surveys have shown 5 typologies in which it has been possible to group all the cavities present in a hypothetical intersection with the excavation. The comparison between surface and hypogeal structural data and the direction of development of cavities has allowed for the definition of highly karstified discontinuity families, thus having a higher risk. The comparison of the collected data has enabled to identify the lithologies and areas having major risk and thus to quantify the probability of intersection with the

  4. Hydrologic response in karstic-ridge wetlands to rainfall and evapotranspiration, central Florida, 2001-2003

    USGS Publications Warehouse

    Knowles, Leel, Jr.; Phelps, G.G.; Kinnaman, Sandra L.; German, Edward R.

    2005-01-01

    Two internally drained karstic wetlands in central Florida-Boggy Marsh at the Hilochee Wildlife Management Area and a large unnamed wetland at the Lyonia Preserve-were studied during 2001-03 to gain a better understanding of the net-recharge function that these wetlands provide, the significance of exchanges with ground water with regard to wetland water budgets, and the variability in wetland hydrologic response to a range of climate conditions. These natural, relatively remote and unaltered wetlands were selected to provide a baseline of natural wetland hydrologic variability to which anthropogenic influences on wetland hydrology could be compared. Large departures from normal rainfall during the study were fortuitous, and allowed monitoring of hydrologic processes over a wide range of climate conditions. Wetland responses varied greatly as a result of climate conditions that ranged from moderate drought to extremely moist. Anthropogenic activities influenced water levels at both study sites; however, because these activities were brief relative to the duration of the study, sufficient data were collected during unimpacted periods to allow for the following conclusions to be made. Water budgets developed for Boggy Marsh and the Lyonia large wetland showed strong similarity between the flux terms of rainfall, evaporation, net change in storage, and the net ground-water exchange residual. Runoff was assumed to be negligible. Of the total annual flux at Boggy Marsh, rainfall accounted for 45 percent; evaporation accounted for 25 percent; net change in storage accounted for 25 percent; and the net residual accounted for 5 percent. At the Lyonia large wetland, rainfall accounted for 44 percent; evaporation accounted for 29 percent; net change in storage accounted for 21 percent; and the net residual accounted for 6 percent of the total annual flux. Wetland storage and ground-water exchange were important when compared to the total water budget at both wetlands. Even

  5. Quantifying the nutrient flux within a lowland karstic catchment

    NASA Astrophysics Data System (ADS)

    McCormack, T.; Naughton, O.; Johnston, P. M.; Gill, L. W.

    2015-01-01

    Nutrient contamination of surface and groundwaters is an issue of growing importance as the risks associated with agricultural runoff escalate due to increasing demands on global food production. In this study, the nutrient flux occurring within the surface and groundwaters of a lowland karst catchment in western Ireland was investigated with the aid of alkalinity sampling and a hydrological model. Water samples were collected and tested from a variety of rivers, lakes (or turloughs), boreholes and springs at monthly intervals over a three year period. Alkalinity sampling was used to elucidate the contrasting hydrological functioning between different turloughs. Such disparate hydrological functioning was further investigated with the aid of a hydrological model which allowed for an estimate of allogenic and autogenic derived nutrient loading into the karst system. The model also allowed for an investigation of mixing within the turloughs, comparing observed behaviours with the hypothetical conservative behaviour allowed for by the model. Results indicated that at the system outlet to the sea, autogenic recharge had added approximately 35% to the total flow and approximately 85% to the total N-load. Within some turloughs, nutrient loads were found to reduce over the flooded period, even though the turloughs hydrological functioning (and the hydrological model) suggested this should not occur. As such, it was determined that nutrient loss processes were occurring within the system. Denitrification was deemed to be the main process reducing nitrogen concentrations within the turloughs whereas phosphorus loss is thought to occur mostly within the diffuse/epikarst zone.

  6. Quantifying the nutrient flux within a lowland karstic catchment

    NASA Astrophysics Data System (ADS)

    McCormack, T.; Naughton, O.; Johnston, P. M.; Gill, L. W.

    2015-10-01

    Nutrient contamination of surface and groundwaters is an issue of growing importance as the risks associated with agricultural runoff escalate due to increasing demands on global food production. In this study, the nutrient flux occurring within the surface and groundwaters of a lowland karst catchment in western Ireland was investigated with the aid of alkalinity sampling and a hydrological model. Water samples were tested from a variety of rivers, lakes (or turloughs), boreholes and springs at monthly intervals over three years. Alkalinity sampling was used to elucidate the contrasting hydrological functioning between different turloughs. Such disparate hydrological functioning was further investigated with the aid of a hydrological model which allowed for an estimate of allogenic and autogenic derived nutrient loading into the karst system. The model also allowed for an investigation of mixing within the turloughs, comparing observed behaviours with the hypothetical conservative behaviour allowed for by the model. Within the turloughs, nutrient concentrations were found to reduce over the flooded period, even though the turloughs hydrological functioning (and the hydrological model) suggested this should not occur. As such, it was determined that nutrient loss processes were occurring within the system. Denitrification during stable flooded periods (typically 3-4 months per year) was deemed to be the main process reducing nitrogen concentrations within the turloughs whereas phosphorus loss is thought to occur mostly via sedimentation and subsequent soil deposition. The results from this study suggest that, in stable conditions, ephemeral lakes can impart considerable nutrient losses on a karst groundwater system.

  7. Source and flux of POC in a karstic area in the Changjiang River watershed: impacts of reservoirs and extreme drought

    NASA Astrophysics Data System (ADS)

    Ji, Hongbing; Li, Cai; Ding, Huaijian; Gao, Yang

    2016-06-01

    Isotopes of carbon (C) and nitrogen (N) along with C / N ratios of particulate organic carbon (POC) were used to identify source and transformation of organic carbon in the suspended and surface sediments in a typical karstic watershed (the Wujiang River, an important tributary of the Changjiang River). Isotope data for suspended sediments indicate that POC was mainly derived from phytoplankton and C3-dominated soil with an increased contribution of phytoplankton in sites directly affected by the reservoir. In contrast, the POC in surface sediments was mainly derived from C3- and C4-dominated soil with little reservoir influence. The positive correlations of carbon and nitrogen isotopes between suspended and surface sediments indicated that these two carbon pools are tightly coupled. Our conservative estimation suggests that 1.17 × 1010 g of POC is transported to the Three Gorges Reservoir during the study period in 2013. POC yield in the Wujiang River (0.13 t km-2 yr-1) is much lower than those of large rivers with a high abundance of carbonate minerals. Based on the distribution pattern of POC yield, it is inferred that carbonate minerals (lithology) do not contribute significantly to the riverine POC. The cascade of reservoirs and extreme drought had a significant influence on the POC flux in the Wujiang River.

  8. Discovery of a Katablepharis sp. in the Columbia River estuary that is abundant during the spring and bears a unique large ribosomal subunit sequence element

    PubMed Central

    Kahn, Peter; Herfort, Lydie; Peterson, Tawnya D; Zuber, Peter

    2014-01-01

    Heterotrophic protists play significant roles in pelagic food webs as bacterivorous and herbivorous consumers. However, heterotrophic protists—unlike autotrophic ones—are often difficult to track since they tend to lack features such as photosynthetic pigments that allow for remote sensing or for bulk characterization. Difficulty in the identification of heterotrophic protists has often resulted in lumping them into broad groups, but there is a strong need to develop methods that increase the spatial and temporal resolution of observations applied to particular organisms in order to discover the drivers of population structure and ecological function. In surveys of small subunit rRNA, gene (SSU) sequences of microbial eukaryotes from the Columbia River to the Pacific Ocean, the heterotrophic flagellate Katablepharis sp. were found to dominate protist assemblages (including autotrophic and heterotrophic fractions) in the spring, prior to the freshet. We discovered a 332 base pair unique sequence element (USE) insertion in the large subunit rRNA gene (28S) that is not present in other katablepharids or in any other eukaryote. Using this USE, we were able to detect Katablepharis within mixed assemblages in river, estuarine, and oceanic samples and determine spatial and temporal patterns in absolute abundance through quantitative PCR and fluorescence in situ hybridization. Given their high abundance and repeatable temporal patterns of occurrence, we hypothesize that the Columbia River Estuary Katablepharis (Katablepharis CRE) plays an important role in estuarine biogeochemical and ecosystem function. PMID:25168204

  9. Discovery of a Katablepharis sp. in the Columbia River estuary that is abundant during the spring and bears a unique large ribosomal subunit sequence element.

    PubMed

    Kahn, Peter; Herfort, Lydie; Peterson, Tawnya D; Zuber, Peter

    2014-10-01

    Heterotrophic protists play significant roles in pelagic food webs as bacterivorous and herbivorous consumers. However, heterotrophic protists-unlike autotrophic ones-are often difficult to track since they tend to lack features such as photosynthetic pigments that allow for remote sensing or for bulk characterization. Difficulty in the identification of heterotrophic protists has often resulted in lumping them into broad groups, but there is a strong need to develop methods that increase the spatial and temporal resolution of observations applied to particular organisms in order to discover the drivers of population structure and ecological function. In surveys of small subunit rRNA, gene (SSU) sequences of microbial eukaryotes from the Columbia River to the Pacific Ocean, the heterotrophic flagellate Katablepharis sp. were found to dominate protist assemblages (including autotrophic and heterotrophic fractions) in the spring, prior to the freshet. We discovered a 332 base pair unique sequence element (USE) insertion in the large subunit rRNA gene (28S) that is not present in other katablepharids or in any other eukaryote. Using this USE, we were able to detect Katablepharis within mixed assemblages in river, estuarine, and oceanic samples and determine spatial and temporal patterns in absolute abundance through quantitative PCR and fluorescence in situ hybridization. Given their high abundance and repeatable temporal patterns of occurrence, we hypothesize that the Columbia River Estuary Katablepharis (Katablepharis CRE) plays an important role in estuarine biogeochemical and ecosystem function. PMID:25168204

  10. Further Studies on the Physical and Biogeochemical Causes for Large Interannual Changes in the Patagonian Shelf Spring-Summer Phytoplankton Bloom Biomass

    NASA Technical Reports Server (NTRS)

    Signorini, Sergio R.; Garcia, Virginia M.T.; Piola, Alberto R.; Evangelista, Heitor; McClain, Charles R.; Garcia, Carlos A.E.; Mata, Mauricio M.

    2009-01-01

    A very strong and persistent phytoplankton bloom was observed by ocean color satellites during September - December 2003 along the northern Patagonian shelf. The 2003 bloom had the highest extent and chlorophyll a (Chl-a) concentrations of the entire Sea-viewing Wide Field-of-view Sensor (SeaWiFS) period (1997 to present). SeaWiFS-derived Chl-a exceeded 20 mg/cu m in November at the bloom center. The bloom was most extensive in December when it spanned more than 300 km across the shelf and nearly 900 km north-south (35degS to 43degS). The northward reach and the deep penetration on the shelf of the 2003 bloom were quite anomalous when compared with other years, which showed the bloom more confined to the Patagonian shelf break (PSB). The PSB bloom is a conspicuous austral spring-summer feature detected by ocean color satellites and its timing can be explained using the Sverdrup critical depth theory. Based on high-resolution numerical simulations, in situ and remote sensing data, we provide some suggestions for the probable mechanisms responsible for that large interannual change of biomass as seen by ocean color satellites. Potential sources of macro and micro (e.g., Fe) nutrients that sustain the high phytoplankton productivity of the Patagonian shelf waters are identified, and the most likely physical processes that maintain the nutrient balance in the region are discussed.

  11. Large deformation analysis and synthesis of elastic closed-loop mechanism made of a certain spring wire described by free curves

    NASA Astrophysics Data System (ADS)

    Iwatsuki, Nobuyuki; Kosaki, Takashi

    2015-07-01

    Recently novel mechanisms with compact size and without many mechanical elements such as bearing are strongly required for medical devices such as surgical operation devices. This paper describes analysis and synthesis of elastic link mechanisms of a single spring beam which can be manufactured by NC coiling machines. These mechanisms are expected as disposable micro forceps. Smooth Curvature Model(SCM) with 3rd order Legendre polynomial curvature functions is applied to calculate large deformation of a curved cantilever beam by taking account of the balance between external and internal elastic forces and moments. SCM is then extended to analyze large deformation of a closed-loop curved elastic beam which is composed of multiple free curved beams. A closed-loop elastic link is divided into two free curved cantilever beams each of which is assumed as serially connected free curved cantilever beams described with SCM. The sets of coefficients of Legendre polynomials of SCM in all free curved cantilever beams are determined by taking account of the force and moment balance at connecting point where external input force is applied. The sets of coefficients of Legendre polynomials of a nonleaded closed-loop elastic link are optimized to design a link mechanism which can generate specified output motion due to input force applied at the assumed dividing point. For example, two planar micro grippers with a single pulling input force are analyzed and designed. The elastic deformation analyzed with proposed method agrees very well with that calculated with FEM. The designed micro gripper can generate the desired pinching motion. The proposed method can contribute to design compact and simple elastic mechanisms without high calculation costs.

  12. Unprotected karst resources in western Iran: the environmental impacts of intensive agricultural pumping on the covered karstic aquifer, a case in Kermanshah province

    NASA Astrophysics Data System (ADS)

    Taheri, Kamal; Taheri, Milad; Parise, Mario

    2015-04-01

    Bare and covered karst areas, with developed karstic aquifers, cover 35 percent of the Kermanshah province in western Iran. These aquifers are the vital sources for drinking and agricultural water supplies. Over the past decade, intensive groundwater use (exploitation) for irrigation imposed a significant impact on the carbonate environments. The huge amount of groundwater over-exploitations has been carried out and still goes on by local farmers in the absence of appropriate governance monitoring control. Increasing in water demands, for more intense crop production, is an important driving force toward groundwater depletion in alluvial aquifers. Progressive groundwater over-exploitations from underlying carbonate rocks have led to dramatic drawdown in alluvial aquifers and deep karst water tables. Detecting new sources of groundwater extractions and prohibiting the karst water utilization for agricultural use could be the most effective strategy to manage the sustainability of covered karst aquifers. Anthropogenic pressures on covered karst aquifers have magnified the drought impacts and caused dryness of most of the karst springs and deep wells. In this study, the combination of geophysical and geological studies was used to estimate the most intensively exploited agricultural zones of Islam Abad plain in the southwestern Kermanshah province using GIS. The results show that in the past decade a great number of deep wells were drilled through the overburden alluvial aquifer and reached the deep karst water resources. However, the difficulties involved in monitoring deep wells in covered karst aquifer were the main cause of karst water depletion. Overexploitation from both alluvial and karst aquifers is the main reason for drying out the Arkawazi, Sharafshah, Gawrawani karst springs, and the karst drinking water wells 1, 3 and 5 of Islam Abad city. Karst spring landscape destructions, fresh water supply deficit for inhabitants, decreasing of tourism and

  13. Snowmelt infiltration and storage within a karstic environment, Vers Chez le Brandt, Switzerland

    NASA Astrophysics Data System (ADS)

    Meeks, Jessica; Hunkeler, Daniel

    2015-10-01

    Even though karstic aquifers are important freshwater resources and frequently occur in mountainous areas, recharge processes related to snowmelt have received little attention thus far. Given the context of climate change, where alterations to seasonal snow patterns are anticipated, and the often-strong coupling between recharge and discharge in karst aquifers, this research area is of great importance. Therefore, we investigated how snowmelt water transits through the vadose and phreatic zone of a karst aquifer. This was accomplished by evaluating the relationships between meteorological data, soil-water content, vadose zone flow in a cave 53 m below ground and aquifer discharge. Time series data indicate that the quantity and duration of meltwater input at the soil surface influences flow and storage within the soil and epikarst. Prolonged periods of snowmelt promote perched storage in surficial soils and encourage surficial, lateral flow to preferential flow paths. Thus, in karstic watersheds overlain by crystalline loess, a typical pedologic and lithologic pairing in central Europe and parts of North America, soils can serve as the dominant mechanism impeding infiltration and promoting shallow lateral flow. Further, hydrograph analysis of vadose zone flow and aquifer discharge, suggests that storage associated with shallow soils is the dominant source of discharge at time scales of up to several weeks after melt events, while phreatic storage becomes import during prolonged periods without input. Soils can moderate karst aquifer dynamics and play a more governing role on karst aquifer storage and discharge than previously credited. Overall, this signifies that a fundamental understanding of soil structure and distribution is critical when assessing recharge to karstic aquifers, particularly in cold regions.

  14. A combined methodology of vulnerability mapping and groundwater flow models for the management of karstic aquifers

    NASA Astrophysics Data System (ADS)

    Kavouri, Konstantina; Karatzas, George; Plagnes, Valérie; Varouchakis, Emmanouil

    2013-04-01

    The present study examines the application of a distributed flow model to a typical Mediterranean karstic aquifer and the importance of the input information. The site of interest is located at the eastern part of Crete and extends to an area of 167 km² mainly of coverless limestone. The geological and climatic conditions of the area are representative of the Mediterranean karst. Also, the information on geological and hydrological characteristics is limited, which is also very common for these systems. The developed model is a combination of the Equivalent Porous Continuum with Discrete Fractures (EPC-DF) modeling approach and the GIS-based vulnerability mapping method PaPRIKa. The EPC-DF method is commonly used for the simulation of systems characterized by dual porosity. In the present study the karstic system is represented by a porous aquifer which also has a principal drainage axe. The model is developed using the finite element code FEFLOW (WASY) which allows for the integration of discrete features such as channels in a porous matrix. The PaPRIKa method is a multi-criteria cartographic method for the evaluation of intrinsic vulnerability of karstic systems, which considers four criteria: the existence of a Protection cover (P map), the lithological properties of the Reservoir (R map), the duality of Infiltration (I map) and the degree of Karstification (Ka map). It spatially describes both structural and functioning characteristics of the karst, providing a simple and realistic conceptual scheme. In the developed model the distribution of the parameters follows the cartographic limits provided by i) the P and I maps for the assignment of recharge, and ii) the R and Ka maps for the assignment of the hydraulic parameters of the saturated zone. The obtained simulated results of groundwater levels are in a good agreement with the selected field measurements. The overall aim of the present study is the development of a flexible tool for the management of water

  15. A large-scale simulation model to assess karstic groundwater recharge over Europe and the Mediterranean

    NASA Astrophysics Data System (ADS)

    Hartmann, A.; Gleeson, T.; Rosolem, R.; Pianosi, F.; Wada, Y.; Wagener, T.

    2015-06-01

    Karst develops through the dissolution of carbonate rock and is a major source of groundwater contributing up to half of the total drinking water supply in some European countries. Previous approaches to model future water availability in Europe are either too-small scale or do not incorporate karst processes, i.e. preferential flow paths. This study presents the first simulations of groundwater recharge in all karst regions in Europe with a parsimonious karst hydrology model. A novel parameter confinement strategy combines a priori information with recharge-related observations (actual evapotranspiration and soil moisture) at locations across Europe while explicitly identifying uncertainty in the model parameters. Europe's karst regions are divided into four typical karst landscapes (humid, mountain, Mediterranean and desert) by cluster analysis and recharge is simulated from 2002 to 2012 for each karst landscape. Mean annual recharge ranges from negligible in deserts to > 1 m a-1 in humid regions. The majority of recharge rates range from 20 to 50% of precipitation and are sensitive to subannual climate variability. Simulation results are consistent with independent observations of mean annual recharge and significantly better than other global hydrology models that do not consider karst processes (PCR-GLOBWB, WaterGAP). Global hydrology models systematically under-estimate karst recharge implying that they over-estimate actual evapotranspiration and surface runoff. Karst water budgets and thus information to support management decisions regarding drinking water supply and flood risk are significantly improved by our model.

  16. Reconstructions of spring/summer precipitation for the Eastern Mediterranean from tree-ring widths and its connection to large-scale atmospheric circulation

    NASA Astrophysics Data System (ADS)

    Touchan, Ramzi; Xoplaki, Elena; Funkhouser, Gary; Luterbacher, Jürg; Hughes, Malcolm K.; Erkan, Nesat; Akkemik, Ünal; Stephan, Jean

    2005-07-01

    This study represents the first large-scale systematic dendroclimatic sampling focused on developing chronologies from different species in the eastern Mediterranean region. Six reconstructions were developed from chronologies ranging in length from 115 years to 600 years. The first reconstruction (1885-2000) was derived from principal components (PCs) of 36 combined chronologies. The remaining five, 1800-2000, 1700-2000, 1600-2000, 1500-2000 and 1400-2000 were developed from PCs of 32, 18, 14, 9, and 7 chronologies, respectively. Calibration and verification statistics for the period 1931-2000 show good levels of skill for all reconstructions. The longest period of consecutive dry years, defined as those with less than 90% of the mean of the observed May-August precipitation, was 5 years (1591-1595) and occurred only once during the last 600 years. The longest reconstructed wet period was 5 years (1601-1605 and 1751-1755). No long term trends were found in May-August precipitation during the last few centuries. Regression maps are used to identify the influence of large-scale atmospheric circulation on regional precipitation. In general, tree-ring indices are influenced by May-August precipitation, which is driven by anomalous below (above) normal pressure at all atmospheric levels and by convection (subsidence) and small pressure gradients at sea level. These atmospheric conditions also control the anomaly surface air temperature distribution which indicates below (above) normal values in the southern regions and warmer (cooler) conditions north of around 40°N. A compositing technique is used to extract information on large-scale climate signals from extreme wet and dry summers for the second half of the twentieth century and an independent reconstruction over the last 237 years. Similar main modes of atmospheric patterns and surface air temperature distribution related to extreme dry and wet summers were identified both for the most recent 50 years and the last

  17. Microbial community diversity associated with moonmilk deposits in a karstic cave system in Ireland

    NASA Astrophysics Data System (ADS)

    Rooney, D.; Hutchens, E.; Clipson, Nick; McDermott, Frank

    2009-04-01

    has been unaltered by human disturbance or practices. The aim of this study was to examine microbial community diversity associated with moonmilk deposits at Ballynamintra Cave, Ireland using automated ribosomal intergenic spacer analysis (ARISA). The results revealed considerable bacterial and fungal diversity associated with moonmilk in a karstic cave system, suggesting that the microbial community implicated in moonmilk formation may be more diverse than previously thought. These results suggest that microbes may have important functional roles in subterranean environments. Although the moonmilk in this study was largely comprised of calcite, microbial involvement in calcite precipitation could result in the bioavailability of a range of organic compounds for subsequent microbial metabolism. References: Baskar, S., Baskar, R., Mauclaire, L., and McKenzie, J.A. 2006. Microbially induced calcite precipitation in culture experiments: Possible origin for stalactites in Sahastradhara caves, Dehradun, India. Current Science 90: 58-64. Burford, E.P., Fomina, M., Gadd, G. 2003. Fungal involvement in bioweathering and biotrasformations of rocks and minerals. Min Mag 67(6):1172-1155. Engel, A.S., Stern, L.A., Bennett, P.C. 2004. Microbial contributions to cave formation: new insights into sulfuric acid speleogenesis. Geology 32(5): 369-372. Gadd, G.M. (2004). Mycotransformation of organic and inorganic substrates. Mycologist 18: 60-70. Northup, D., Barns, S.M., Yu, Laura, E., Spilde, M.N., Schelble, R.T., Dano, K.E., Crossey, L.J., Connolly, C.A., Boston, P.J., and Dahm, C.N. 2003. Diverse microbial communities inhabiting ferromanganese deposits in Lechuguilla and Spider Caves. Environmental Microbiology 5(11): 1071-1086.

  18. Walking with springs

    NASA Astrophysics Data System (ADS)

    Sugar, Thomas G.; Hollander, Kevin W.; Hitt, Joseph K.

    2011-04-01

    Developing bionic ankles poses great challenges due to the large moment, power, and energy that are required at the ankle. Researchers have added springs in series with a motor to reduce the peak power and energy requirements of a robotic ankle. We developed a "robotic tendon" that reduces the peak power by altering the required motor speed. By changing the required speed, the spring acts as a "load variable transmission." If a simple motor/gearbox solution is used, one walking step would require 38.8J and a peak motor power of 257 W. Using an optimized robotic tendon, the energy required is 21.2 J and the peak motor power is reduced to 96.6 W. We show that adding a passive spring in parallel with the robotic tendon reduces peak loads but the power and energy increase. Adding a passive spring in series with the robotic tendon reduces the energy requirements. We have built a prosthetic ankle SPARKy, Spring Ankle with Regenerative Kinetics, that allows a user to walk forwards, backwards, ascend and descend stairs, walk up and down slopes as well as jog.

  19. Gene expression in caged fish as indicators of contaminants exposure in tropical karstic water bodies.

    PubMed

    Rodríguez-Fuentes, Gabriela; Luna-Ramírez, Karen S; Soto, Mélina; Richardson, Kristine L

    2012-04-01

    Karstic areas in Yucatan are very permeable, which allows contaminants to move rapidly into the aquifer. In the present study, we evaluated gene expression of vitellogenin (VTG) and cytochrome P-450 1A (CYP1A) in caged juvenile zebrafish deployed for 15 days in 13 different water bodies, cenotes and aguadas, throughout karstic region of the Yucatan peninsula. Gene expression was evaluated using qRT-PCR. Results indicated induction of VTG in 7 water bodies with respect to reference cage. The highest relative VTG expression, about 3000 times higher than reference cage, was found in an aguada close to a cattle farm. CYP1A induction with respect to reference cage was observed in 3 water bodies, all of them located near villages or used for tourist activities. Pollutants and biomarkers of effect should be monitored in these water bodies in order to have a better understanding of the actual levels of pollutants that are present at Yucatan's aquifer and the potential risk to human and environmental health. PMID:22014761

  20. Continuous Ecosystem Stoichiometry (C:N:P) in a Large Spring-fed River Reveals Decoupled N and P Assimilatory Dynamics

    NASA Astrophysics Data System (ADS)

    Cohen, M. J.; Douglass, R. L.; Martin, J. B.; Thomas, R. G.; Heffernan, J. B.; Foster, C. R.

    2010-12-01

    Diel variation in solutes offers insight into lotic ecosystem processes. Diel variation in dissolved oxygen (DO) is the standard method to estimate aquatic primary production (C fixation). Recently, diel variation in nitrate concentration was used to infer rates and pathways of N processing. From coupled C and N measurements, stoichiometric ratios of nutrient assimilation can be obtained, and variation therein linked back to environmental drivers and ecological changes. Here we present data obtained using an in situ phosphate sensor (Cycle-P, WetLabs, Philomath OR) that permits coupled high frequency C, N and P measurements. We collected hourly samples over 3 two-week deployments in the Ichetucknee River, a large (Q ~ 10 m3 s-1), productive (GPP ~ 6 g C m-2 d-1), entirely spring-fed river in north Florida. We observed average soluble reactive P (SRP) concentrations of 44, 41 and 45 µg/L for Dec-09, Feb-10 and Apr-10, respectively, and marked diel variation that averaged 6.7±0.9 µg/L. Observed river concentrations were consistently at or below the flow-weighted average input concentration of the 6 main springs that feed the river (49 µg/L) suggesting net SRP removal over the 5 km reach. Removal from co-precipitation with calcite or Fe-oxides is unlikely since variation in Fe and Ca is smaller than, and out of phase with, P variation. Since internal stores are presumed to be at steady-state given conditions of constant discharge, the balance of P export likely occurs as organic matter. Based on discharge during each deployment, diel variation of P concentrations indicate system-wide assimilation of 1505 ± 423 g P d-1, or 8.0 ± 2.3 mg P m-2 d-1 over the 17 ha of benthic surface area. Contemporaneous measurements of DO and nitrate implied average ecosystem stoichiometry (C:N:P) of 267:14:1, consistent with production dominated by submerged aquatic macrophytes rather than algae and other microflora. Of particular interest is the observation that diel variation in

  1. Integration of Electric Resistivity Profile and Infiltrometer Measurements to Calibrate a Numerical Model of Vertical Flow in Fractured and Karstic Limestone.

    NASA Astrophysics Data System (ADS)

    Caputo, M. C.; de Carlo, L.; Masciopinto, C.; Nimmo, J. R.

    2007-12-01

    Karstic and fractured aquifers are among the most important drinking water resources. At the same time, they are particularly vulnerable to contamination. A detailed scientific knowledge of the behavior of these aquifers is essential for the development of sustainable groundwater management concepts. Due to their special characteristics of extreme anisotropy and heterogeneity, research aimed at a better understanding of flow, solute transport, and biological processes in these hydrogeologic systems is an important scientific challenge. This study integrates a geophysical technique with an infiltrometer test to better calibrate a mathematical model that quantifies the vertical flow in karstic and fractured limestone overlying the deep aquifer of Alta Murgia (Southern Italy). Knowledge of the rate of unsaturated zone percolation is needed to investigate the vertical migration of pollutants and the vulnerability of the aquifer. Sludge waste deposits in the study area have caused soil-subsoil contamination with toxics. The experimental test consisted of infiltrometer flow measurements, more commonly utilized for unconsolidated granular porous media, during which subsoil electric resistivity data were collected. A ring infiltrometer 2 m in diameter and 0.3 m high was sealed to the ground with gypsum. This large diameter yielded infiltration data representative of the anisotropic and heterogeneous rock, which could not be sampled adequately with a small ring. The subsurface resistivity was measured using a Wenner-Schlumberger electrode array. Vertical movement of water in a fracture plane under unsaturated conditions has been investigated by means of a numerical model. The finite difference method was used to solve the flow equations. An internal iteration method was used at every time step to evaluate the nodal value of the pressure head, in agreement with the mass- balance equation and the characteristic functional relationships of the coefficients.

  2. Elucidation of denitrification mechanism in karstic Ryukyu limestone aquifer

    NASA Astrophysics Data System (ADS)

    Hijikawa, K.

    2014-12-01

    Nitrate (NO3-) concentrations in public water supplies have risen above acceptable levels in many areas of the world including Japan, largely as a result of contamination by human and animal waste and overuse of fertilizers. A previous study has characterized nitrate concentrations in groundwater in this area is a higher than the upper value (44mgL-1) of environmental quality criteria on one hands. On the other hand, there exists points where the concentration of nitric acid is not detected, which suggests the possibility of denitrification. During early 2000, a new analytical procedure for nitrate isotopic measurement, termed the "denitrifier method", was established. With the development of the nitrate isotope tracer method, much research has been reported detailing sources of groundwater nitrate and denitrification mechanisms. This study presents a pilot case study (in the southern part of Okinawa Main Island, Japan, where Ryukyu limestone is extensively distributed) using the combined stable isotope ratios of major elements (C, N and S) as net recorders of the biogeochemical reactions with the aim of elucidation of denitrification mechanism in Ryukyu limestone aquifer. As a result, significant decreases in nitrate concentrations due to denitrification were observed in groundwater at some locations, which induced increases in isotope ratios up to 59.7‰ for δ15NNO3. These points of groundwater were located above the cutoff wall of the underground dam and near the fault. It is considered that the residence time of the groundwater is longer than the other points at these denitrification points, and that reduction condition tends to be formed in the groundwater. However, the rapid rise of the groundwater level due to rainfall is likely to occur in the Ryukyu limestone aquifer, where the ground water was found to have changed dynamically from the reduction condition to the oxidation condition which a denitrification (has not occured)does not occur. Moreover, the

  3. THE QTRACER2 PROGRAM FOR TRACER-BREAKTHROUGH CURVE ANALYSIS FOR TRACER TESTS IN KARSTIC AQUIFERS AND OTHER HYDROLOGIC SYSTEMS

    EPA Science Inventory

    Tracer testing is generally regarded as the most reliable and efficient method of gathering surface and subsurface hydraulic information. This is especially true for karstic and fractured-rock aquifers. Qualitative tracing tests have been conventionally employed in most karst s...

  4. Analysing Submarine Groundwater Discharge (SGD)-borne Dissolved Organic Matter (DOM) in a karstic aquifer, Co. Galway, Ireland.

    NASA Astrophysics Data System (ADS)

    Kelly, Tara; Rocha, Carlos

    2014-05-01

    Submarine Groundwater Discharge (SGD) constitutes an "invisible" link between land and sea, transporting allochthonous and autochthonous dissolved organic matter (DOM), nutrients and metals to the ocean via the subterranean estuary. The latter acts as a powerful bioreactor where groundwater, in transit from land to sea, mixes with seawater leading to active modulation of both DOM content and chemical makeup of SGD. DOM in freshwater systems is a key component of the global carbon cycle. Climate change may hence increase the concentration of allochthonous carbon entering the oceans as terrestrial DOC is released from soils at higher temperatures, and transported via SGD. Presently, little is known about the effects of SGD-borne DOM on coastal carbon cycling. SGD therefore represents a dynamic reservoir and analysis is critical to forecast future environmental management programmes, both on a local and global scale. Labile DOM plays a crucial role in microbial remineralisation processes, and as it breaks down it contributes to the groundwater nutrient pool. Locally, this could add to eutrophication. However, if refractory carbon is present, it will be recalcitrant to mineralisation in transit and at the subterranean estuary. This putative additional input will thus imply the contribution of SGD to oceanic carbon storage. This study is focused on Kinvara Bay (Galway, western Ireland), the focal point for waters discharging from the Gort-Kinvara karstic aquifer. This aquifer represents the ideal study location for evaluation of SGD contribution to the coastal DOM pool, as SGD is focused in the bay, surface drainage is very limited, and groundwater travels across a large catchment area with a short residence time, minimising DOM modification in transit. DOM samples collected in the field have been analysed using Three-Dimensional Excitation Emission Matrix Fluorescence (3D-EEMF) and High Temperature Catalytic Oxidation. PARAFAC is subsequently used as a tool to

  5. Small karstic Dobra River (Croatia) suggested as natural laboratory for impactite research

    NASA Astrophysics Data System (ADS)

    Frančišković-Bilinski, Stanislav; Bilinski, Halka; Sikder, Arif M.

    2016-04-01

    An unexpected anomaly of magnetic susceptibility (MS) was observed in stream sediments of the upper course of the karstic Dobra River (Croatia). Preliminary results pointed to a possible impactite, formed by a shock event caused by a meteorite impact or by volcanic processes [1]. In addition to geophysical experiments, petrological and geochemical studies are reported [2, 3]. The multidisciplinary work for identification and confirmation of impact structure is still in progress. Results will be presented and the difficulties due to weathering and transport processes will be discussed and compared with recent literature [4, 5]. In reported results numerous evidences exist, which are in support of impact origin, such as vesicular glass with quench texture, ballen textures in the lechatelierite, presence of Troilite, etc. We suggest that the Dobra River from its source to the abyss in Ogulin (Upper Dobra) is a possible natural laboratory for studying processes of mixing between impactite material and fluvial sediments within a small area, including spherules exposed to water and in the overbank sediments. Especially the introduction of isotope studies in this research and enlargement of multinational team of experts are suggested. Literature: [1] Franči\\vsković-Bilinski, S., Bilinski, H., Scholger, R., Tomašić, N., Maldini, K. (2014): Magnetic spherules in sediments of the sinking karstic Dobra River (Croatia). Journal of soils and sediments 14(3), 600-614. [2] Franči\\vsković-Bilinski, S., Sikder, A.M., Bilinski, H., Castano, C.E., Garman, G.C. (2015): Traces of meteorite impact in the sediments of karstic Dobra River (Croatia). 15th International multidisciplinary scientific geoconference SGEM 2015 Conference proceedings, Vol. 1, 507-514. [3] Sikder, A.M., Franči\\vsković-Bilinski, S., Bilinski, H., Castano, C.E., Clifford, D.M., Turner, J.B., Garman, G.C. (2015): Petrographic analysis of the magnetic spherules from the sediments of karastic Dobra River

  6. Secondary phosphate mineralization in a karstic environment in Central Sri Lanka

    NASA Astrophysics Data System (ADS)

    Dahanayake, Kapila; Subasinghe, S. M. N. D.

    1989-07-01

    At Eppawala in central Sri Lanka secondary phosphate mineralization is intimately associated with laminated fabrics within depressions (sinkholes and smaller cavities) formed in the thick weathering profiles of a hilly terrain underlain by a Precambrian apatite-bearing formation. The lowermost levels of the profile show extensive zones of leaching where derived apatite crystals occur within fine-grained, laminated stromatolite sequences. The stromatolitic groundmass, which diagenetically formed by percolating oxygenated phosphate and carbonate-rich groundwaters, is impregnated by the phosphate minerals francolite and collophane. Scanning electron microscopy (SEM) reveals that fine filaments, characteristic of microorganisms, are associated with the secondary phosphate mineralization. Continuous degradation and fragmentation of the stromatolitic mat has produced pellets, peloids, and intraclasts all enriched in secondary apatite. Degrading recrystallization around the edges of the primary apatite crystals has developed coated grains. The widespread occurrence of phosphate-enriched allochems in stromatolitic groundmasses is a unique development of a modern phosphorite in a karstic environment.

  7. Spring Dunes

    NASA Technical Reports Server (NTRS)

    2006-01-01

    22 July 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dunes in the north polar region of Mars. In this scene, the dunes, and the plain on which the dunes reside, are at least in part covered by a bright carbon dioxide frost. Dark spots indicate areas where the frost has begun to change, either by subliming away to expose dark sand, changing to a coarser particle size, or both. The winds responsible for the formation of these dunes blew from the lower left (southwest) toward the upper right (northeast).

    Location near: 76.3oN, 261.2oW Image width: 3 km (1.9 mi) Illumination from: lower left Season: Northern Spring

  8. Possible crater-based karstic and lacustrine terrain in Tyrrhena Terra, Mars.

    NASA Astrophysics Data System (ADS)

    Baioni, Davide; Soare, Richard

    2015-04-01

    We have identified two craters in Tyrrhena Terra, Mars (19.560 S, 67.480 E, 18.500 S, 68.340 E), where crater-floor deposits display traits that are consistent with formation by karst-driven processes. Tyrrhena Terra is located in the cratered highlands of the southern Martian hemisphere, immediately to the northeast of Hellas Planitia and to the southeast of Isidis Planitia. Crater diameters in the region vary widely, from metres to 100km. Most of these craters are moderately to highly degraded and many show bright deposits on their floors. Here, we present some of the key characteristics associated with these bright deposits and explain why a "karstic" formation hypothesis is reasonable. First and foremost amongst these characteristics are depressions that are ubiquitous within the bright deposits. They display a variety of plan forms ranging from rounded, circular, elongated, polygonal and drop-like to elliptical. Moreover, they display strong morphometric (sizes) and morphologic (shapes, bottoms, walls) similarities with the karst depressions that are common on limestone and evaporite terrains on the Earth. Some depression morphologies - rounded/elongate - could be the result of formation by coalescence. We infer that the depressions are dolines, karstic features formed polygenetically by corrosion and solution-related intra-crater processes; we also demonstrate why the formation of the depressions by aeolian, periglacial, volcanic or impact-related processes seems less plausible by karst-related ones. Interestingly, polygonal cracks whose morphology points to an origin by dessication often cross-cut the bright deposits; as such, their crater floor presence could be an important co-marker of ponded or running liquid water within the craters where they are observed.

  9. Characteristics of subtropic karstic Dinaride Lake in its unstable geothectonic regime

    NASA Astrophysics Data System (ADS)

    Krstic, N.

    2009-04-01

    Geotectonic evolution of Dinarides started in Mid-Cretaceous, when this part of African Plate approached Stable Europe. Geodynamic style is as follow: "subduction-termination / colision (Paleocene / Eocene), collision (Eocene), postcollision / colapse (Oligocene / early Miocene)" (Cvetković et al., 2004). Longlasting melting of lower crust (ibid: fig. 11). "The gravity colapse of the Dinaride orogen is inferred from the faulth pattern and shape" as mirrored in sedimetary record of lacustrine basin (ibid). So, at the turn from Paleogene to Neogene on Dinarides was formed large subtropical karstic system of lakes. Another part of Africa is the Adriatic Plate mowing northwards under the Alps (Schmid et al., 2006: fig. 1 and there in). Two coal seams (brown coal and lignite), formed during colateral catastrofic earthquakes, indicate two main phases of tectonic push of Adriatic plate. Evolution of Dinaric Lake(s) from shallow freshwater aquatorium toward deep saline lake was influenced by northward movements of Adriatic Plate and the response of Pannonian Mass. The sediment column of Dinaride Neogene was devided into tree parts (Milojević, 1963). They lay, in places, above reddish (continental) Oligocene sediments with Helix (Čičić & Milojević, 1977), but mostly in the Sava trough (Ugljevik, Banovići). Otherwise above Mesozoic and Paleozoic rocks. First part: basal zone above lie several brown coal seams indicating that the Adriatic Plate push was divided into phases. Catastrophic earthquake pull down the forest together with its large dwellers (Chalicotherium grande, an of Ungulata with claws) and sorted tree trunks at southern side of the lake Plevlja (Krstić et al., 1994). In this period freshwater ostracodes, and numerous characean gyrogonites, among them a genus similar to the Oligocene Harissichara, fill up some of beds. None of Congeria pelecipods are present. Charophyta algae making yellowish-brown limestone in Middle Bosnian depression lie just bellow

  10. Variable stiffness torsion springs

    NASA Technical Reports Server (NTRS)

    Alhorn, Dean C. (Inventor); Polites, Michael E. (Inventor)

    1995-01-01

    In a torsion spring the spring action is a result of the relationships between the torque applied in twisting the spring, the angle through which the torsion spring twists, and the modulus of elasticity of the spring material in shear. Torsion springs employed industrially have been strips, rods, or bars, generally termed shafts, capabable of being flexed by twisting their axes. They rely on the variations in shearing forces to furnish an internal restoring torque. In the torsion springs herein the restoring torque is external and therefore independent of the shearing modulus of elasticity of the torsion spring shaft. Also provided herein is a variable stiffness torsion spring. This torsion spring can be so adjusted as to have a given spring constant. Such variable stiffness torsion springs are extremely useful in gimballed payloads such as sensors, telescopes, and electronic devices on such platforms as a space shuttle or a space station.

  11. Variable stiffness torsion springs

    NASA Technical Reports Server (NTRS)

    Alhorn, Dean C. (Inventor); Polites, Michael E. (Inventor)

    1994-01-01

    In a torsion spring the spring action is a result of the relationships between the torque applied in twisting the spring, the angle through which the torsion spring twists, and the modulus of elasticity of the spring material in shear. Torsion springs employed industrially have been strips, rods, or bars, generally termed shafts, capabable of being flexed by twisting their axes. They rely on the variations in shearing forces to furnish an internal restoring torque. In the torsion springs herein the restoring torque is external and therefore independent of the shearing modulus of elasticity of the torsion spring shaft. Also provided herein is a variable stiffness torsion spring. This torsion spring can be so adjusted as to have a given spring constant. Such variable stiffness torsion springs are extremely useful in gimballed payloads such as sensors, telescopes, and electronic devices on such platforms as a space shuttle or a space station.

  12. Microgravity methods for characterization of groundwater-storage changes and aquifer properties in the karstic Madison aquifer in the Black Hills of South Dakota, 2009-12

    USGS Publications Warehouse

    Koth, Karl R.; Long, Andrew J.

    2012-01-01

    A study of groundwater storage in the karstic Madison aquifer in the Black Hills of South Dakota using microgravity methods was conducted by the U.S. Geological Survey in cooperation with West Dakota Water Development District, South Dakota Department of Environment and Natural Resources, and Lawrence County. Microgravity measurements from 2009 to 2012 were used to investigate groundwater-storage changes and effective porosity in unconfined areas of the Madison aquifer. Time-lapse microgravity surveys that use portable high-sensitivity absolute and relative gravimeters indicated temporal-gravity changes as a result of changing groundwater mass. These extremely precise measurements of gravity required characterization and removal of internal instrumental and external environmental effects on gravity from the raw data. The corrected data allowed groundwater-storage volume to be quantified with an accuracy of about plus or minus 0.5 foot of water per unit area of aquifer. Quantification of groundwater-storage change, coupled with water-level data from observation wells located near the focus areas, also was used to calculate the effective porosity at specific altitudes directly beneath gravity stations. Gravity stations were established on bedrock outcrops in three separate focus areas for this study. The first area, the Spring Canyon focus area, is located to the south of Rapid City with one gravity station on the rim of Spring Canyon near the area where Spring Creek sinks into the Madison aquifer. The second area, the Doty focus area, is located on outcrops of the Madison Limestone and Minnelusa Formation to the northwest of Rapid City, and consists of nine gravity stations. The third area, the Limestone Plateau focus area, consists of a single gravity station in the northwestern Black Hills located on an outcrop of the Madison Limestone. An absolute-gravity station, used to tie relative-gravity survey data together, was established on a relatively impermeable

  13. Geophysical and geomorphological investigations of a Quaternary karstic paleolake and its underground marine connection in Cassis (Bestouan, Cassis, SE France)

    NASA Astrophysics Data System (ADS)

    Romey, Carole; Rochette, Pierre; Vella, Claude; Arfib, Bruno; Andrieu-Ponel, Valérie; Braucher, Régis; Champollion, Cédric; Douchet, Marc; Dussouillez, Philippe; Hermitte, Daniel; Mattioli, Emanuela; Parisot, Jean-Claude; Schwenninger, Jean-Luc

    2014-06-01

    An original karstic system in a coastal alluvial plain located in a carbonate environment (Cassis, Provence - SE France) was studied using a multi-method approach (electrical resistivity tomography, gravimetric, passive seismic survey), combined with geomorphologic methods, surface observations and drilling. Limestone dissolution and/or cavity collapse led to the development of a polje, which was filled rapidly by erosion of Aptian marls. The combination of several dating and paleoenvironmental proxies indicates that the polje was filled during a glacial period (MIS 6, 8 or 10, i.e. in the 130-360 ka age range). This discovery has implications for the understanding of karst processes. The connection between the polje and the three km-long Bestouan underwater karstic conduit with submarine outlet is strongly suggested by sedimentological studies and geophysical prospections.

  14. Monitoring of water storage in karstic area (Larzac, France) with a iGrav continuous superconducting gravimeter

    NASA Astrophysics Data System (ADS)

    Le Moigne, N.; Champollion, C.; chery, J.; Deville, S.; Doerflinger, E.; Collard, P.; Flores, B.

    2013-12-01

    Quantitative knowledge of groundwater storage and transfer in karstic area is crucial for water resources management and protection. As the karst hydro-geological properties are highly heterogeneous and scale dependent, geophysical observations such as gravity are necessary to fill the gap between local (based on boreholes, moisture sensors, ...) and global (based on chemistry, river flow, ...) studies. Since almost 2 years, the iGrav #002 superconducting gravimeter is continuously operating in the French GEK (Géodésie des Eaux Karstiques) observatory in the Larzac karstic plateau (south of France). First the evaluation of the iGrav data (calibration, steps and drift) will be presented. Then a careful analyze of the topographic and building effects will be done. Finally the first interpretation of the hydrogeological signal and the integration an extensive observation dataset (borehole water level, evapotranspiration and electrical resistivity) are studied.

  15. Microgravimetric and ground penetrating radar geophysical methods to map the shallow karstic cavities network in a coastal area (Marina Di Capilungo, Lecce, Italy)

    NASA Astrophysics Data System (ADS)

    Leucci, Giovanni; De Giorgi, Lara

    2010-06-01

    The coastal area Marina di Capilungo located ~50km south-west of Lecce (Italy) is one of the sites at greatest geological risk in the Salento peninsula. In the past few decades, Marina di Capilungo has been affected by a series of subsidence events, which have led in some cases to the partial collapse of buildings and road surfaces. These events had both social repercussions, causing alarm and emergency situations, and economic ones in terms of the funds for restoration. With the aim of mapping the subsurface karstic features, and so to assess the dimensions of the phenomena in order to prevent and/or limit the ground subsidence events, integrated geophysical surveys were undertaken in an area of ~70000m2 at Marina di Capilungo. Large volume voids such as karstic cavities are excellent targets for microgravity surveys. The absent mass of the void creates a quantifiable disturbance in the earth's gravitational field, with the magnitude of the disturbance directly proportional to the volume of the void. Smaller shallow voids can be detected using ground-penetrating radar (GPR). Microgravimetric and GPR geophysical methods were therefore used. An accurate interpretation was obtained using small station spacing and accurate geophysical data processing. The interpretation was facilitated by combining the modelling of the data with the geological and topographic information for explored caves. The GPR method can complement the microgravimetric technique in determining cavity depths and in verifying the presence of off-line features and numerous areas of small cavities, which may be difficult to be resolved with only microgravimetric data. However, the microgravimetric can complement GPR in delineating with accuracy the shallow cavities in a wide area where GPR measurements are difficult. Furthermore, microgravity surveys in an urban environment require effective and accurate consideration of the effects given by infrastructures, such as buildings, as well as those given

  16. Dissolution on Titan and on Earth: Toward the age of Titan's karstic landscapes

    NASA Astrophysics Data System (ADS)

    Cornet, Thomas; Cordier, Daniel; Bahers, Tangui Le; Bourgeois, Olivier; Fleurant, Cyril; Mouélic, Stéphane Le; Altobelli, Nicolas

    2015-06-01

    Titan's polar surface is dotted with hundreds of lacustrine depressions. Based on the hypothesis that they are karstic in origin, we aim at determining the efficiency of surface dissolution as a landshaping process on Titan, in a comparative planetology perspective with the Earth as reference. Our approach is based on the calculation of solutional denudation rates and allow inference of formation timescales for topographic depressions developed by chemical erosion on both planetary bodies. The model depends on the solubility of solids in liquids, the density of solids and liquids, and the average annual net rainfall rates. We compute and compare the denudation rates of pure solid organics in liquid hydrocarbons and of minerals in liquid water over Titan and Earth timescales. We then investigate the denudation rates of a superficial organic layer in liquid methane over one Titan year. At this timescale, such a layer on Titan would behave like salts or carbonates on Earth depending on its composition, which means that dissolution processes would likely occur but would be 30 times slower on Titan compared to the Earth due to the seasonality of precipitation. Assuming an average depth of 100 m for Titan's lacustrine depressions, these could have developed in a few tens of millions of years at polar latitudes higher than 70°N and S, and a few hundreds of million years at lower polar latitudes. The ages determined are consistent with the youth of the surface (<1 Gyr) and the repartition of dissolution-related landforms on Titan.

  17. Characteristics of subtropic karstic Dinaride Lake in its unstable geothectonic regime

    NASA Astrophysics Data System (ADS)

    Krstic, N.

    2009-04-01

    Geotectonic evolution of Dinarides started in Mid-Cretaceous, when this part of African Plate approached Stable Europe. Geodynamic style is as follow: "subduction-termination / colision (Paleocene / Eocene), collision (Eocene), postcollision / colapse (Oligocene / early Miocene)" (Cvetković et al., 2004). Longlasting melting of lower crust (ibid: fig. 11). "The gravity colapse of the Dinaride orogen is inferred from the faulth pattern and shape" as mirrored in sedimetary record of lacustrine basin (ibid). So, at the turn from Paleogene to Neogene on Dinarides was formed large subtropical karstic system of lakes. Another part of Africa is the Adriatic Plate mowing northwards under the Alps (Schmid et al., 2006: fig. 1 and there in). Two coal seams (brown coal and lignite), formed during colateral catastrofic earthquakes, indicate two main phases of tectonic push of Adriatic plate. Evolution of Dinaric Lake(s) from shallow freshwater aquatorium toward deep saline lake was influenced by northward movements of Adriatic Plate and the response of Pannonian Mass. The sediment column of Dinaride Neogene was devided into tree parts (Milojević, 1963). They lay, in places, above reddish (continental) Oligocene sediments with Helix (Čičić & Milojević, 1977), but mostly in the Sava trough (Ugljevik, Banovići). Otherwise above Mesozoic and Paleozoic rocks. First part: basal zone above lie several brown coal seams indicating that the Adriatic Plate push was divided into phases. Catastrophic earthquake pull down the forest together with its large dwellers (Chalicotherium grande, an of Ungulata with claws) and sorted tree trunks at southern side of the lake Plevlja (Krstić et al., 1994). In this period freshwater ostracodes, and numerous characean gyrogonites, among them a genus similar to the Oligocene Harissichara, fill up some of beds. None of Congeria pelecipods are present. Charophyta algae making yellowish-brown limestone in Middle Bosnian depression lie just bellow

  18. Application of time-series analyses to the hydrological functioning of an Alpine karstic system: the case of Bange-L'Eau-Morte

    NASA Astrophysics Data System (ADS)

    Mathevet, T.; Lepiller, M. L.; Mangin, A.

    This paper analyses the hydrological functioning of the Bange-L’Eau-Morte karstic system using classical and original techniques, recession curves, correlation and spectral analyses, noise analysis and wavelet analyses. The main characteristics that can be deduced are the recession coefficients, the dynamic volume of storage, the response time of the system, the quickflow and baseflow components and the snowmelt characteristics. The non-stationary and timescale-dependent behaviour of the system is studied and particular features of the runoff are shown. The step-by-step use of these different techniques provides a general methodology applicable to different karstic systems to provide quantifiable and objective criteria for differentiation and comparison of karstic systems.

  19. Tectonic and karstic effects on the western Taurus region, southwestern Turkey: Relations to the present temperature gradients and total organic carbon content

    SciTech Connect

    Demirel, I.H.; Gunay, Y.

    2000-06-01

    The western Taurus region is one of the promising hydrocarbon provinces and the largest karstic terrain of Turkey. The Mesozoic Beydaglari units deposited in the study area are composed mainly of a carbonate succession which has potential hydrocarbon source rocks of various ages. To confirm the tectonic and karstic influence on the regional temperature gradient and total organic carbon content, subsurface data obtained from four drillholes, and the results of the surface samples and water samples analyses, were used. The low salinity values (less than 2,500 mg/liter) of the formation water, and the measured hole temperatures, indicate the presence of the meteoric water circulation in the geologic section. Since the Late Miocene, intensive tectonic deformations and karstification have provided the development of the aquifer characteristics of the Beydaglari units. Water circulation in the aquifer system has influenced the total organic carbon content and karstic conduits within carbonates.

  20. Planktonic cyanobacteria of the tropical karstic lake Lagartos from the Yucatan Peninsula, Mexico.

    PubMed

    Valadez, Francisco; Rosiles-González, Gabriela; Almazán-Becerril, Antonio; Merino-Ibarra, Martin

    2013-06-01

    The tropical karstic lakes on the Mexican Caribbean Sea coast are numerous. However, there is an enormous gap of knowledge about their limnological conditions and micro-algae communities. In the present study, surface water samples were collected monthly from November 2007 to September 2008 to provide taxonomical composition and biovolume of planktonic cyanobacteria of the lake Lagartos from State of Quintana Roo, Mexico. Water temperature, pH, conductivity, salinity, soluble reactive phosphorus (SRP), dissolved inorganic nitrogen (DIN), and soluble reactive silica (SRSi) levels were also analyzed. A total of 22 species were identified. Chroococcales and Oscillatoriales dominated the phytoplankton assemblages during the study period. Chroococcus pulcherrimus, Coelosphaerium confertum, Cyanodyction iac, Phormidium pachydermaticum and Planktolyngbya contorta were recorded for the first time in Mexico. A surplus of DIN (mean value of 42.7 microM) and low concentrations of SRP (mean value of 1.0 microM) promoted the enhanced growth and bloom formation of cyanobacteria. The mean biovolume was 3.22 x 10(8) microm3/mL, and two biovolume peaks were observed; the first was dominated by Microcystis panniformis in November 2007 (7.40 x 10(8) microm3/mL), and the second was dominated by Oscillatoriaprinceps in April 2008 (6.55 x 10(8) microm3/mL). Water quality data, nitrates enrichment, and trophic state based on biovolume, indicated that Lagartos is a hyposaline, secondarily phosphorus-limited, and eutrophic lake, where the cyanobacteria flora was composed mainly by non-heterocystous groups. PMID:23885602

  1. Vulnerability of a public supply well in a karstic aquifer to contamination

    USGS Publications Warehouse

    Katz, B.G.; McBride, W.S.; Hunt, A.G.; Crandall, C.A.; Metz, P.A.; Eberts, S.M.; Berndt, M.P.

    2009-01-01

    To assess the vulnerability of ground water to contamination in the karstic Upper Floridan aquifer (UFA), age-dating tracers and selected anthropogenic and naturally occurring compounds were analyzed in multiple water samples from a public supply well (PSW) near Tampa, Florida. Samples also were collected from 28 monitoring wells in the UFA and the overlying surficial aquifer system (SAS) and intermediate confining unit located within the contributing recharge area to the PSW. Age tracer and geochemical data from the earlier stage of the study (2003 through 2005) were combined with new data (2006) on concentrations of sulfur hexafluoride (SF6), tritium (3H), and helium-3, which were consistent with binary mixtures of water for the PSW dominated by young water (less than 7 years). Water samples from the SAS also indicated mostly young water (less than 7 years); however, most water samples from monitoring wells in the UFA had lower SF6 and 3H concentrations than the PSW and SAS, indicating mixtures containing high proportions of older water (more than 60 years). Vulnerability of the PSW to contamination was indicated by predominantly young water and elevated nitrate-N and volatile organic compound concentrations that were similar to those in the SAS. Elevated arsenic (As) concentrations (3 to 19 ??g/L) and higher As(V)/As(III) ratios in the PSW than in water from UFA monitoring wells indicate that oxic water from the SAS likely mobilizes As from pyrite in the UFA matrix. Young water found in the PSW also was present in UFA monitoring wells that tap a highly transmissive zone (43- to 53-m depth) in the UFA. ?? 2008 National Ground Water Association.

  2. Urban waste landfill planning and karstic groundwater resources in developing countries: the example of Lusaka (Zambia)

    NASA Astrophysics Data System (ADS)

    De Waele, J.; Nyambe, I. A.; Di Gregorio, A.; Di Gregorio, F.; Simasiku, S.; Follesa, R.; Nkemba, S.

    2004-06-01

    Lusaka, the capital city of Zambia with more than two million inhabitants, derives approximately 70% of its water requirements from groundwater sourced in the underlying karstic Lusaka aquifer. This water resource is, therefore, extremely important for the future of the population. The characteristics of the aquifer and the shallow water table make the resource vulnerable and in need of protection and monitoring. A joint project between the Geology Departments of the University of Cagliari and the School of Mines of the University of Zambia, to investigate the "Anthropogenic and natural processes in the Lusaka area leading to environmental degradation and their possible mitigation" was carried out in July 2001. The main objective of the study was to evaluate the extent of the present environmental degradation, assessing the vulnerability of the carbonatic aquifer and the degree of pollution of the groundwater and to make proposals to mitigate adverse environmental effects. Analyses of water samples collected during project indicate some areas of concern, particularly with respect to the levels of ammonia, nitrates and some heavy metals. As groundwater quality and quantity are prerogatives for a healthy and sustainable society, the study offers guidelines for consideration by the local and national authorities. Uptake of these guidelines should result in a number of initiatives being taken, including: (a) closure or reclamation of existing waste dumps; (b) upgrading of existing waste dumps to controlled landfills; (c) establishing new urban waste landfills and plants in geo-environmentally suitable sites; (d) local waste management projects in all compounds (residential areas) to prevent and reduce haphazard waste dumping; (e) enlarging sewerage drainage systems to all compounds; (f) enforcing control on groundwater abstraction and pollution, and demarcation of zones of control at existing drill holes; (g) providing the city with new water supplies from outside the

  3. Use of microbial analysis to evaluate denitrification in the karstic aquifer of Okinawa, Japan

    NASA Astrophysics Data System (ADS)

    Yasumoto, J.

    2014-12-01

    Denitrification, a microbial process in the nitrogen cycle, is a facultative respiratory pathway in which nitrate (NO3-), nitrite (NO2-), nitric oxide (NO), and nitrous oxide (N2O), successively, are reduced to nitrogen gas (N2). This study explores the use of microbial analysis to evaluate the processes involved in nitrate attenuation in groundwater. Polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE) is used to identify denitrifiers based only on their 16SrRNA gene sequences, and Real-Time PCR analysis is used to quantify nitrite reducing genes (nirK and nirS), this suggest that a new methods for detecting denitrification activity by comparing the gene dosage that has been detected by RT-PCR and the value of the δ15NNO3- and δ18ONO3-. This study focuses on a zone of significant NO3- attenuation occurring at underground dam catchment area in the karstic Ryukyu limestone aquifer, which is located southern part of Okinawa, Japan. As a result of microbial analysis, the bacteria were detected at all observation points which have been reported to have denitrification ability. And it has been confirmed that the bacteria has a gene nirS which is related to denitrification. In addition, many bacteria related to denitrification have been extracted from suspended solids more than from groundwater in the aquifer. And, the correlation was high between nirK /nirS gene dosage that has been detected by RT-PCR and the value of the δ15N and δ18O; therefore, this study demonstrates the effectiveness of using Real-Time PCR analysis for providing insights into the processes affecting nitrate attenuation in ground water.

  4. Chemical and biological tracers to determine groundwater flow in karstic aquifer, Yucatan Peninsula

    NASA Astrophysics Data System (ADS)

    Lenczewski, M.; Leal-Bautista, R. M.; McLain, J. E.

    2013-05-01

    Little is known about the extent of pollution in groundwater in the Yucatan Peninsula; however current population growth, both from international tourism and Mexican nationals increases the potential for wastewater release of a vast array of contaminants including personal care products, pharmaceuticals (Rx), and pathogenic microorganisms. Pathogens and Rx in groundwater can persist and can be particularly acute in this region where high permeability of the karst bedrock and the lack of top soil permit the rapid transport of contaminants into groundwater aquifers. The objective of this research is to develop and utilize novel biological and chemical source tracking methods to distinguish between different sources of anthropogenic pollution in degraded groundwater. Although several methods have been used successfully to track fecal contamination sources in small scale studies, little is known about their spatial limitations, as source tracking studies rarely include sample collection over a wide geographical area and with different sources of water. In addition, although source tracking methods to distinguish human from animal fecal contamination are widely available, this work has developed source tracking distinguish between separate human populations is highly unique. To achieve this objective, we collected water samples from a series of drinking wells, cenotes (sinkholes), wastewater treatment plants, and injection wells across the Yucatan Peninsula and examine potential source tracers within the collected water samples. The result suggests that groundwater sources impacted by tourist vs. local populations contain different chemical stressors. This work has developed a more detailed understanding of the presence and persistence of personal care products, pharmaceuticals, and fecal indicators in a karstic system; such understanding will be a vital component for the protection Mexican groundwater and human health. Quantification of different pollution sources

  5. Fish community structure in freshwater karstic water bodies of the Sian Ka'an Reserve in the Yucatan peninsula, Mexico

    USGS Publications Warehouse

    Zambrano, L.; Vazquez-Dominguez, E.; Garcia-Bedoya, D.; Loftus, W.F.; Trexler, J.C.

    2006-01-01

    We evaluated the relationship between limnetic characteristics and fish community structure (based on species richness, abundance and individual size) in contrasting but interconnected inland aquatic habitats of freshwater karstic wetlands in the Yucatan peninsula, Mexico. In the western hemisphere, freshwater karstic wetlands are found in south-eastern Mexico, northern Belize, western Cuba, Andros Island, Bahamas and the Everglades of southern Florida. Only in the Everglades have fish communities been well described. Karstic wetlands are typically oligotrophic because calcium carbonate binds phosphorus, making it relatively unavailable for plants. Fourteen permanent and seasonally flooded water bodies were sampled in both wet and dry seasons in Sian Ka'an Biosphere Reserve, in the Mexican state of Quintana Roo. Water systems were divided by morphology in four groups: cenotes with vegetation (CWV), cenotes without vegetation (CNV), wetlands (WTL), and temporal cenotes (TPC). Discriminant analysis based on physical characteristics such as turbidity, temperature, depth and oxygen confirmed that these habitats differed in characteristics known to influence fish communities. A sample-based rarefaction test showed that species richness was significantly different between water systems groups, showing that WTL and CWV had higher richness values than CNV and TPC. The most abundant fish families, Poeciliidae, Cichlidae and Characidae, differed significantly in average size among habitats and seasons. Seasonal and inter-annual variation, reflecting temporal variation in rainfall, strongly influenced the environmental differences between shallow and deep habitats, which could be linked to fish size and life cycles. Five new records of species were found for the reserve, and one new record for Quintana Roo state. ?? 2006 by Verlag Dr. Friedrich Pfeil.

  6. Water Treatment Technology - Springs.

    ERIC Educational Resources Information Center

    Ross-Harrington, Melinda; Kincaid, G. David

    One of twelve water treatment technology units, this student manual on springs provides instructional materials for two competencies. (The twelve units are designed for a continuing education training course for public water supply operators.) The competencies focus on spring basin construction and spring protection. For each competency, student…

  7. Spring Wheat Breeding

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Common wheat, known as bread wheat, is one of major crops for human food consumption. It is further classified into spring and winter wheat based on the distinct growing seasons. Spring wheat is grown worldwide and usually planted in the spring and harvested in late summer or early fall. In this c...

  8. 1. LOOKING NORTH, SHOWING IODINE SPRING (FOREGROUND), SALT SULPHUR SPRING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. LOOKING NORTH, SHOWING IODINE SPRING (FOREGROUND), SALT SULPHUR SPRING (LEFT BACKGROUND), AND TWIN COTTAGES (UPPER RIGHT) (4 x 5 negative; 5 x 7 print) - Salt Sulpher Springs, U.S. Route 219, Salt Sulphur Springs, Monroe County, WV

  9. Environmental conditions of boreal springs explained by capture zone characteristics

    NASA Astrophysics Data System (ADS)

    Rossi, Pekka M.; Marttila, Hannu; Jyväsjärvi, Jussi; Ala-aho, Pertti; Isokangas, Elina; Muotka, Timo; Kløve, Bjørn

    2015-12-01

    Springs are unique ecosystems, but in many cases they are severely threatened and there is an urgent need for better spring management and conservation. To this end, we studied water quality and quantity in springs in Oulanka National Park, north-east Finland. Multivariate statistical methods were employed to relate spring water quality and quantity to hydrogeology and land use of the spring capture zone. This revealed that most springs studied were affected by locally atypical dolostone-limestone bedrock, resulting in high calcium, pH, and alkalinity values. Using Ward's hierarchical clustering, the springs were grouped into four clusters based on their water chemistry. One cluster consisted of springs affected by past small-scale agriculture, whereas other clusters were affected by the variable bedrock, e.g., springs only 1 km from the dolostone-limestone bedrock area were beyond its calcium-rich impact zone. According to a random forest model, the best predictors of spring water chemistry were spring altitude and the stable hydrogen isotope ratio of the water (δ2H). Thus stable water isotopes could be widely applicable for boreal spring management. They may also provide a rough estimate of groundwater flow route (i.e., whether it is mainly local or regional), which largely determines the chemical characteristics of spring water. Our approach could be applied in other boreal regions and at larger spatial scales for improved classification of springs and for better targeted spring management.

  10. Determination of groundwater travel time in a karst aquifer by stable water isotopes, Tanour and Rasoun spring (Jordan)

    NASA Astrophysics Data System (ADS)

    Hamdan, Ibraheem; Wiegand, Bettina; Sauter, Martin; Ptak, Thomas

    2016-04-01

    . Water Information System, National Master Plan Directorate. Jordan. Hamdan I., Wiegand B., Toll M., Sauter M. (2016) Spring response to precipitation events using δ 18O and δ 2H in the Tanour catchment, NW-Jordan. Isotopes in Environmental and Health Studies journal. Accepted GIEH-2015-0139. Hamdan, I.~in preparation.~Characterization of groundwater flow and vulnerability assessment of karstic aquifer - A case study from Tanour and Rasoun spring catchment (Ajloun, NW-Jordan).~Ph.D. Thesis, University of Göttingen, Germany.

  11. Spring plant phenology and false springs in the conterminous US during the 21st century

    USGS Publications Warehouse

    Allstadt, Andrew J.; Vavrus, Stephen J.; Heglund, Patricia J.; Pidgeon, Anna M.; Thogmartin, Wayne E.; Radeloff, Volker C.

    2015-01-01

    The onset of spring plant growth has shifted earlier in the year over the past several decades due to rising global temperatures. Earlier spring onset may cause phenological mismatches between the availability of plant resources and dependent animals, and potentially lead to more false springs, when subsequent freezing temperatures damage new plant growth. We used the extended spring indices to project changes in spring onset, defined by leaf out and by first bloom, and predicted false springs until 2100 in the conterminous United States (US) using statistically-downscaled climate projections from the Coupled Model Intercomparison Project 5 ensemble. Averaged over our study region, the median shift in spring onset was 23 days earlier in the Representative Concentration Pathway 8.5 scenario with particularly large shifts in the Western US and the Great Plains. Spatial variation in phenology was due to the influence of short-term temperature changes around the time of spring onset versus season long accumulation of warm temperatures. False spring risk increased in the Great Plains and portions of the Midwest, but remained constant or decreased elsewhere. We conclude that global climate change may have complex and spatially variable effects on spring onset and false springs, making local predictions of change difficult.

  12. Springs of Florida

    USGS Publications Warehouse

    Rosenau, Jack C.; Faulkner, Glen L.; Hendry, Charles W., Jr.; Hull, Robert W.

    1977-01-01

    The first comprehensive report of Florida's springs, which contains both a story of the springs and a collection of facts about them, was published thirty years ago (Ferguson and others, 1947). Since then, much additional data on springs have been gathered and the current report, Springs of Florida, makes a wealth of information on springs available to the public. Springs of Florida, prepared by the U.S. Geological Survey in cooperation with the Bureau of Geology, Florida Department of Natural Resources, publishers, and the Bureau of Water Resources Management, Florida Department of Environmental Regulation, is intended to provide sufficient background information for a lucid understanding of the nature and occurrence of the springs in the State.

  13. Anisotropy Modelling of the Fissure-Karstic Aquifer of the Opole-Zawadzkie Major Groundwater Basin (South-West Poland)

    NASA Astrophysics Data System (ADS)

    Wcisło, Marek; Olichwer, Tomasz; Staśko, Stanisław

    2014-12-01

    The problem of the anisotropy and heterogeneity of karstic aquifers has been previously described. The Opole-Zawadzkie Major Groundwater Body (south-west Poland) was chosen for this investigation. The parameters for anisotropy were analysed on the basis of well yield and observation of macro-fractures (field scale) compared with micro-fractures. Sta-tistical tools were used to assess the directions and values of anisotropy. The estimated parameters were tested on two different models realized in Visual Modflow code. The anisotropy of hydraulic conductivity was recognized as an es-sential factor for groundwater flow direction and water table depletion prognosis as well as for water budget modification. The second model (M2), representing anisotropy flow conditions, gave an 11% lower value of safe yield in com-parison with the first model (M1-isotropic). Additionally, anisotropy conditions caused water table lowering and limitation of aquifer recharge. The results of these studies indicate the need for more attention to be paid to the anisotropy problem in the area, where fracture-karstic aquifers are the main source of groundwater supply.

  14. Diversity of Miscellaneous Crenarchaeotic Group archaea in freshwater karstic lakes and their segregation between planktonic and sediment habitats.

    PubMed

    Fillol, Mireia; Sànchez-Melsió, Alexandre; Gich, Frederic; Borrego, Carles M

    2015-04-01

    The Miscellaneous Crenarchaeotic Group (MCG) is an archaeal lineage whose members are widespread and abundant in marine sediments. MCG archaea have also been consistently found in stratified euxinic lakes. In this work, we have studied archaeal communities in three karstic lakes to reveal potential habitat segregation of MCG subgroups between planktonic and sediment compartments. In the studied lakes, archaeal assemblages were strikingly similar to those of the marine subsurface with predominance of uncultured Halobacteria in the plankton and Thermoplasmata and MCG in anoxic, organic-rich sediments. Multivariate analyses identified sulphide and dissolved organic carbon as predictor variables of archaeal community composition. Quantification of MCG using a newly designed qPCR primer pair that improves coverage for MCG subgroups prevalent in the studied lakes revealed conspicuous populations in both the plankton and the sediment. Subgroups MCG-5a and -5b appear as planktonic specialists thriving in euxinic bottom waters, while subgroup MCG-6 emerges as a generalist group able to cope with varying reducing conditions. Besides, comparison of DNA- and cDNA-based pyrotag libraries revealed that rare subgroups in DNA libraries, i.e. MCG-15, were prevalent in cDNA-based datasets, suggesting that euxinic, organic-rich sediments of karstic lakes provide optimal niches for the activity of some specialized MCG subgroups. PMID:25764468

  15. Spring joint with overstrain sensor

    NASA Technical Reports Server (NTRS)

    Phelps, Peter M. (Inventor); Gaither, Bryan W. (Inventor)

    2011-01-01

    A flexible joint may include a conductive compression spring and a pair of non-conductive spring cages disposed at opposite ends of the compression spring to support the compression spring. A conductive member disposed inside the compression spring may extend between the pair of spring cages. One end of the conductive member may be fixed for movement with one of the spring cages and another end of the conductive member may be fixed for movement with the other of the spring cages.

  16. The Investigation of Mass Transfer in the Karasu Karstic Aquifer, Konya, Turkey

    NASA Astrophysics Data System (ADS)

    Ozdemir, Adnan; Nalbantcilar, Tahir

    2002-09-01

    In this study, the changes in the chemical composition of the groundwater along a flow path were examined by using the water samples collected from unconfined, semi-confined and confined parts of the Karasu karstic aquifer. It was determined that transport of bicarbonate, calcium, and magnesium was dominant in unconfined and semi-confined parts of the aquifer, whereas calcite and dolomite precipitate in the confined parts. On the other hand, gypsum dissolution is present in all parts of the aquifer. In addition, the computed saturation indices explain the occurrences and precipitation of travertines in the Goksu Valley, which is the discharge area for the aquifer. Résumé. Les modifications de la composition chimique de l'eau souterraine le long d'un axe d'écoulement ont été étudiées à partir d'échantillons prélevés dans les parties libres, semi-captives et captives de l'aquifère karstique de Karasu. On a mis en évidence que le transport de carbonate, de calcium et de magnésium est prépondérant dans les parties libres et semi-captives de l'aquifère, alors que la calcite et la dolomite précipitent dans les parties captives. En outre, la dissolution du gypse se produit dans toutes les parties de l'aquifère. Par ailleurs, les indices de saturation calculés rendent compte de l'existence et de la précipitation des travertins dans la vallée du Göksu, qui est la zone de décharge de cet aquifère. Resumen. En este estudio, se han examinado los cambios de composición química en las aguas subterráneas a lo largo de una línea de corriente mediante el análisis de muestras recogidas en partes libres, semiconfinadas y cautivas del acuífero cárstico de Karasu. Se ha determinado que el transporte de bicarbonato, calcio y magnesio es dominante en las zonas libres y semiconfinadas, mientras que la calcita y la dolomita precipitan en las zonas confinadas. Por otro lado, la disolución de yesos ocurre en todo el ámbito del acuífero. Además, los

  17. Geomorphological approach in karstic domain: importance of underground water in the Jura mountains.

    NASA Astrophysics Data System (ADS)

    Rabin, Mickael; Sue, Christian; Champagnac, Jean Daniel; Bichet, Vincent; Carry, Nicolas; Eichenberger, Urs; Mudry, Jacques; Valla, Pierre

    2014-05-01

    Jura. The objective is to assess to what extent this powerful landscape analysis tool will be applicable to limestone bedrock settings where groundwater flow might be an important component of the hydrological system. First results show that river slopes and knickpoints are poorly controlled by lithological variation within the Jura mountains. Quantitative analyses reveal abnormal longitudinal profiles, which are controlled by either tectonic and/or karstic processes. Evaluating the contribution of both tectonics and karst influence in the destabilization of river profiles is challenging and appears still unresolved. However these morphometrics signals seem to be in accordance with the presence of active N-S to NW-SE strike-slip faults, controlling both surface runoff and groundwater flow.

  18. Numerical model to support the management of groundwater resources of a coastal karstic aquifer (southern Italy)

    NASA Astrophysics Data System (ADS)

    Polemio, Maurizio; Romanazzi, Andrea

    2013-04-01

    The main purpose of the research is to define management apporouches for a coastal karstic aquifer. The core of the tools uses numerical modelling, applied to groundwater resource of Salento (southern Italy) and criteria to reduce the quantitative and qualitative degradation risks. The computer codes selected for numerical groundwater modelling were MODFLOW and SEAWAT. The approach chosen was based on the concept of a equivalent homogeneous porous medium by which it is assumed that the real heterogeneous aquifer can be simulated as homogeneous porous media within cells or elements. The modelled aquifer portion extends for 2230 km2, and it was uniformly discretized into 97,200 cells, each one of 0.6 km2. Vertically, to allow a good lithological and hydrogeological discretization, the area was divided into 12 layers, from 214 to -350 m asl. Thickness and geometry of layers was defined on the basis of the aquifer conceptualisation based on the 3d knowledge of hydrogeological complexes. For the boundary conditions, inactive cells were used along the boundary with the rest of Murgia-Salento aquifer, as conceptual underground watershed due to the absence of flow. About the sea boundary was used CHD boundary cells (Constant Head Boundary). Additional boundary conditions were used for SEAWAT modelling, as initial concentration and constant concentration, in the latter case for cells shaping the coastline. A mean annual net rainfall (recharge) was calculated in each cell with a GIS elaboration, ranged from 68 to 343 mm, 173 mm an average. The recharge or infiltration was calculated using an infiltration coefficient (IC) (defined as infiltration/net rainfall ratio) for each hydrogeological complex, assuming values equal to 1 inside endorheic areas. The mean annual recharge was equal to 150 mm. The model was implemented using MODFLOW and SEAWAT codes in steady-state conditions to obtain a starting point for following transient scenarios, using piezometric data of thirties as

  19. Karst hydrogeology and hydrochemistry of the Cave Springs basin near Chattanooga, Tennessee

    USGS Publications Warehouse

    Pavlicek, D.J.

    1996-01-01

    The Cave Springs ground-water basin, located near Chattanooga, Tennessee, was chosen as one of the Valley and Ridge physiographic province type area studies for the Appalachian Valley-Piedmont Regional Aquifer-System Analysis study in 1990. Karstic Paleozoic carbonate rocks, residual clay-rich regolith, and coarse alluvium form the aquifer framework. Recharge from rainfall dispersed over the basin enters the karst aquifer through the thick regolith. The area supplying recharge to the Cave Springs Basin is approximately 7 square miles. Recharge from North Chickamauga Creek may contribute recharge to the Cave Springs Basin along losing reaches. The flow medium consists of mixed dolomite and limestone with cavernous and fracture porosity. Flow type as determined by the coefficient of variation of long-term continuous specific conductance (18 and 15 percent) from two wells completed in cavernous intervals about 150 feet northeast of Cave Springs, indicates an aquifer with conduit flow. Flow type, based on the ratio (6:1) of spring flood-flow discharge to spring base-flow discharge, indicates an aquifer with diffuse flow. Conduit flow probably dominates the aquifer system west of Cave Springs Ridge from the highly transmissive, unconfined, alluvium capped aquifer and along losing reaches of North Chickamauga Creek. Diffuse flow probably predominates in the areas along and east of Cave Springs Ridge covered with the thick, clay-rich regolith that forms a leaky confining layer. Based on average annual long-term precipitation and runoff records, the amount of water available for recharge to Cave Springs is 11.8 cubic feet per second. The mean annual long-term discharge of Cave Springs is 16.4 cubic feet per second which leaves 4.6 cubic feet per second of recharge unaccounted for. As determined by low-flow stream discharge measurements, recharge along losing reaches of North Chickamauga Creek may be an important source of unaccounted-for-recharge to the Cave Springs Basin

  20. Population structure, egg production and gut content pigment of large grazing copepods during the spring phytoplankton bloom in the Oyashio region

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Atsushi; Onishi, Yuka; Omata, Aya; Kawai, Momoka; Kaneda, Mariko; Ikeda, Tsutomu

    2010-09-01

    As a basis for analyzing development of six large grazing copepods ( Eucalanus bungii, Metridia pacifica, M. okhotensis, Neocalanus cristatus, N. flemingeri and N. plumchrus) in the Oyashio region, quasi-daily twin-NORPAC net (0.33 and 0.10 mm mesh) hauls were taken through the upper 150 m and 500 m at a station southwest of Hokkaido before (9-14 March) and after (6-30 April) the onset of the phytoplankton bloom in 2007. Based on additional fresh specimens collected from 0-150 m, egg production of E. bungii, M. pacifica and M. okhotensis, and gut pigments of late copepodid stages in each species were evaluated. Total zooplankton biomass was greater from 10 April onward by a factor of 2- to 8-fold the previous levels. This increase of the 0-150 m biomass was caused by development of Neocalanus spp. copepodids and upward migration of resting E. bungii. Egg production of E. bungii peaked on 18 April, while abundance of its nauplii and C1 peaked on 20 and 25 April, respectively. Sex ratio and C6-female gonad maturation index of E. bungii showed new recruitment to C6 during 20-30 April, likely derived from a population that over-wintered as C3 or C4. Egg production and hatchability of M. pacifica and M. okhotensis were highly variable and no temporal trend was detected. Comparison with field abundance data for Metridia spp. suggests that our estimates of egg production and hatchability are too low, despite care with experimental conditions. All the Neocalanus species utilize the bloom as energy for juvenile growth. Neocalanus cristatus developed from C2 through C4, and stage duration of C3 was estimated to be 24 days. Neocalanus flemingeri also developed from C1 through C3, and stage durations of C1 and C2 were estimated to be 7-9 days. Neocalanus plumchrus occurred in small numbers from mid-April onward. The stage duration estimates for Neocalanus spp. are similar to those reported from the high-nutrition southeastern Bering Sea shelf. Gut pigment variation clearly

  1. Denitrification and inference of nitrogen sources in the karstic Floridan Aquifer

    USGS Publications Warehouse

    Heffernan, J.B.; Albertin, A.R.; Fork, M.L.; Katz, B.G.; Cohen, M.J.

    2011-01-01

    Aquifer denitrification is among the most poorly constrained fluxes in global and regional nitrogen budgets. The few direct measurements of denitrification in groundwaters provide limited information about its spatial and temporal variability, particularly at the scale of whole aquifers. Uncertainty in estimates of denitrification may also lead to underestimates of its effect on isotopic signatures of inorganic N, and thereby confound the inference of N source from these data. In this study, our objectives are to quantify the magnitude and variability of denitrification in the Upper Floridan Aquifer (UFA) and evaluate its effect on N isotopic signatures at the regional scale. Using dual noble gas tracers (Ne, Ar) to generate physical predictions of N2 gas concentrations for 112 observations from 61 UFA springs, we show that excess (i.e. denitrification-derived) N2 is highly variable in space and inversely correlated with dissolved oxygen (O2). Negative relationship between O2 and ??15NNO 3 across a larger dataset of 113 springs, well-constrained isotopic fractionation coefficients, and strong 15N: 18O covariation further support inferences of denitrification in this uniquely organic-matter-poor system. Despite relatively low average rates, denitrification accounted for 32% of estimated aquifer N inputs across all sampled UFA springs. Back-calculations of source ??15NNO 3 based on denitrification progression suggest that isotopically-enriched nitrate (NO3-) in many springs of the UFA reflects groundwater denitrification rather than urban- or animal-derived inputs. ?? Author(s) 2011.

  2. The use of water marks mapping to understand flood overflow events inside karstic cavities: Cueva Fría and Cueva Rosa (Asturias, NW Spain)

    NASA Astrophysics Data System (ADS)

    González Lemos, Saúl; Stoll, Heather M.

    2014-05-01

    Several karst systems in Asturias (NW Spain) present evidence of fluvial deposits cemented in speleothems that may provide good chronology of past flood events inside the caves. This flood record is under research in two karstic caves of this region, Cueva Fría and Cueva Rosa, which have in common the presence of a perennial stream inside the cave and a low gradient of the cave passage. Immediately after a flood overflow event, water marks, foam and detritus are visible at different heights on the cave walls and correspond to heights of bottlenecks in overflow drainage through the cave passage. Flood events also deposit sand and gravel on terraces on the cave wall and move large volumes of sand in the cave bed. We have noted that detrital particles (like sand or silt particles) are preserved as inclusions inside the stalagmites and that their abundance inside coeval stalagmites decreases as altitude and distance from the perennial stream increase, supporting its fluvial affinity. However, not all the stalagmites that contain detrital particles are located close to the perennial streams. In this work, we have mapped the water marks preserved in the cave walls to reconstruct water levels associated to flood overflow events of different magnitude. We have found that water mark correlation along the cave passage is very useful to define the hydrological behaviour and flood model of the cave during these extreme events. The water mark mapping and correlation have been also useful to prove that during periods of high rainfall, the movement of the sand-bars inside the cave can cover partially or completely active stalagmites, facilitating the cementation process and trapping abundant detrital material inside the stalagmite carbonate. 14C and U/Th dating of the stalagmites can provide a chronology for the detrital rich layers, so that the abundance of fluvial material in the stalagmites can reveal periods of enhanced vs. reduced flooding in the cave over the past several

  3. New method for quantification of vuggy porosity from digital optical borehole images as applied to the karstic Pleistocene limestone of the Biscayne aquifer, southeastern Florida

    USGS Publications Warehouse

    Cunningham, K.J.; Carlson, J.I.; Hurley, N.F.

    2004-01-01

    Vuggy porosity is gas- or fluid-filled openings in rock matrix that are large enough to be seen with the unaided eye. Well-connected vugs can form major conduits for flow of ground water, especially in carbonate rocks. This paper presents a new method for quantification of vuggy porosity calculated from digital borehole images collected from 47 test coreholes that penetrate the karstic Pleistocene limestone of the Biscayne aquifer, southeastern Florida. Basically, the method interprets vugs and background based on the grayscale color of each in digital borehole images and calculates a percentage of vuggy porosity. Development of the method was complicated because environmental conditions created an uneven grayscale contrast in the borehole images that makes it difficult to distinguish vugs from background. The irregular contrast was produced by unbalanced illumination of the borehole wall, which was a result of eccentering of the borehole-image logging tool. Experimentation showed that a simple, single grayscale threshold would not realistically differentiate between the grayscale contrast of vugs and background. Therefore, an equation was developed for an effective subtraction of the changing grayscale contrast, due to uneven illumination, to produce a grayscale threshold that successfully identifies vugs. In the equation, a moving average calculated around the circumference of the borehole and expressed as the background grayscale intensity is defined as a baseline from which to identify a grayscale threshold for vugs. A constant was derived empirically by calibration with vuggy porosity values derived from digital images of slabbed-core samples and used to make the subtraction from the background baseline to derive the vug grayscale threshold as a function of azimuth. The method should be effective in estimating vuggy porosity in any carbonate aquifer. ?? 2003 Published by Elsevier B.V.

  4. Coil spring venting arrangement

    DOEpatents

    McCugh, R.M.

    1975-10-21

    A simple venting device for trapped gas pockets in hydraulic systems is inserted through a small access passages, operated remotely, and removed completely. The device comprises a small diameter, closely wound coil spring which is pushed through a guide temporarily inserted in the access passage. The guide has a central passageway which directs the coil spring radially upward into the pocket, so that, with the guide properly positioned for depth and properly oriented, the coil spring can be pushed up into the top of the pocket to vent it. By positioning a seal around the free end of the guide, the spring and guide are removed and the passage is sealed.

  5. Spring and valve skirt

    SciTech Connect

    Moore, L.

    1986-07-29

    This patent describes an engine having a valve guide operatively mounting a valve stem and its associated valve spring and spring retainer for actuation of the valve stem by a valve actuator. An improvement is described comprising: a hollow, generally cylindrical shaped skirt means having a side portion forming an interior with one open end and having at its other end an end portion extending inwardly and formed with an axial opening therein communicating to the interior. The skirt means is mounted on and about the valve stem and spring retainer and about its spring so as to move with the valve stem and to cover the spring retainer and most of the portion of the valve spring and the valve stem extending outwardly from the valve guide except for an outermost end of the stem which extends through the opening in the end portion for actuation by the actuator , such that the inwardly extending end portion lies between the outermost end of the stem and an outermost end of the spring retainer to allow for retrofitting insertion of the skirt means over existing valve stems without removal of the spring and spring retainer. Excessive oil is presented from seeping between and valve guide and the valve stem thus preventing excessive carbon build-up in the combustion area, sticking valves, fouled plugs and high exhaust emissions.

  6. Rocky Mountain Carbonate Spring Deposit development

    NASA Astrophysics Data System (ADS)

    Rainey, Dustin Kyle

    Relict Holocene carbonate spring deposits containing diverse biotic and abiotic depositional textures are present at Fall Creek cold sulphur springs, Alberta, Fairmont Hot Springs, British Columbia, and Hot Creek cold springs, British Columbia. The relict deposits are formed mainly of low-magnesium crystalline calcite contained in laterally continuous strata. Paleo-flow regimes were characterized by extensive sheet flow that increased the surface area of spring water exposed to the atmosphere. Calcite precipitated inorganically from spring water that attained CaCO3 supersaturation through agitation-induced CO2 degassing that was facilitated by elevated flow rates and a large surface area as spring water flowed down-slope. Thus, the deposits contain only minor amounts of detrital, mechanically deposited, and biogenic carbonate. Evaporation was only a minor contributor to CaCO3 supersaturation, mainly in quiescent environments. Photosynthetic CO2 removal did not measurably contribute to CaCO3 supersaturation. Calcite crystals precipitated in biotic facies formed from low to moderately supersaturated spring water, whereas abiotic dendrite crystals formed rapidly from highly supersaturated spring water. Calcite passively nucleated on cyanobacteria, bryophytes and macrophytes, and was probably facilitated by cyanobacterial extracellular polymeric substances. Cyanobacterial filaments and stromatolites are integral parts of all three deposits, whereas bryophytes were restricted to the Fall Creek and Hot Creek deposits. Diagenetic microbial degradation of crystalline calcite was common to all three deposits, but recrystallization was limited to the Fall Creek deposit. The amount and location of calcite precipitation relative to the vents was controlled by the concentrations of Ca2+ and HCO3- in solution, and discharge volume fluctuations. Spring water with high [Ca2+] and [HCO 3-] precipitated large amounts of calcite proximal to the vents (e.g. Fairmont), whereas spring

  7. Results from the Big Spring basin water quality monitoring and demonstration projects, Iowa, USA

    USGS Publications Warehouse

    Rowden, R.D.; Liu, H.; Libra, R.D.

    2001-01-01

    Agricultural practices, hydrology, and water quality of the 267-km2 Big Spring groundwater drainage basin in Clayton County, Iowa, have been monitored since 1981. Land use is agricultural; nitrate-nitrogen (-N) and herbicides are the resulting contaminants in groundwater and surface water. Ordovician Galena Group carbonate rocks comprise the main aquifer in the basin. Recharge to this karstic aquifer is by infiltration, augmented by sinkhole-captured runoff. Groundwater is discharged at Big Spring, where quantity and quality of the discharge are monitored. Monitoring has shown a threefold increase in groundwater nitrate-N concentrations from the 1960s to the early 1980s. The nitrate-N discharged from the basin typically is equivalent to over one-third of the nitrogen fertilizer applied, with larger losses during wetter years. Atrazine is present in groundwater all year; however, contaminant concentrations in the groundwater respond directly to recharge events, and unique chemical signatures of infiltration versus runoff recharge are detectable in the discharge from Big Spring. Education and demonstration efforts have reduced nitrogen fertilizer application rates by one-third since 1981. Relating declines in nitrate and pesticide concentrations to inputs of nitrogen fertilizer and pesticides at Big Spring is problematic. Annual recharge has varied five-fold during monitoring, overshadowing any water-quality improvements resulting from incrementally decreased inputs. ?? Springer-Verlag 2001.

  8. AMS radiocarbon dating of pollen concentrates in a karstic lake system

    NASA Astrophysics Data System (ADS)

    Fletcher, William; Zielhofer, Christoph; Mischke, Steffen; Campbell, Jennifer; Bryant, Charlotte; Fink, David; Xu, Xiaomei

    2016-04-01

    In lake sediments where terrestrial macrofossils are rare or absent, AMS radiocarbon dating of pollen concentrates represents an important alternative solution for developing a robust and high resolution chronology suitable for Bayesian modelling of age-depth relationships. Here we report an application of the dense media separation approach (Vandergoes and Prior, Radiocarbon 45:479-492, 2003) to Holocene lake sediments from karstic Lake Sidi Ali, Morocco (33° 03'N, 05° 00'W; 2,080 m a.s.l.). Paired dates on terrestrial (macrofossil) and aquatic (ostracod) samples, and dating of bulk sediment surface material at the site indicate varying reservoir effects of up to 900 yr and highlight the need to date terrestrial carbon sources. Dating of pollen concentrates is a viable approach at Lake Sidi Ali, as pollen concentrations are high (~200,000 grains/cc), and pollen assemblages typically contain only minor percentages (<1%) of aquatic pollen. Following laboratory trials, 23 pollen concentrates alongside laboratory standards (anthracite, IAEA C5 wood) were prepared and dated following the heavy liquid (sodium polytungstate, SPT) density separation protocol. A series of SPT solutions of progressively decreasing density (1.9-1.15 s.g.) were used to divide the samples into several fractions. The pollen purity of these fractions was evaluated by microscopic analysis of smear slides, and the richest fraction(s) were selected for dating. Sieving at 10 μm and at 50/125 μm (depending on the size of predominant pollen grains) was used to further concentrate the pollen grains, and the samples were freeze dried to determine the dry weight of material. The results show that the highest purity of pollen is sample dependent and may typically be achieved in the fractions precipitating at 1.4-1.2 s.g. With sieving, terrestrial pollen purity of ~50-80% can be achieved, offering a considerable improvement in terms of terrestrial carbon content over bulk sediment. These values reflect

  9. A Magnet Spring Model

    ERIC Educational Resources Information Center

    Fay, T. H.; Mead, L.

    2006-01-01

    The paper discusses an elementary spring model representing the motion of a magnet suspended from the ceiling at one end of a vertical spring which is held directly above a second magnet fixed on the floor. There are two cases depending upon the north-south pole orientation of the two magnets. The attraction or repelling force induced by the…

  10. Valve-spring Surge

    NASA Technical Reports Server (NTRS)

    Marti, Willy

    1937-01-01

    Test equipment is described that includes a system of three quartz indicators whereby three different pressures could be synchronized and simultaneously recorded on a single oscillogram. This equipment was used to test the reliction of waves at ends of valve spring, the dynamical stress of the valve spring for a single lift of the valve, and measurement of the curve of the cam tested. Other tests included simultaneous recording of the stress at both ends of the spring, spring oscillation during a single lift as a function of speed, computation of amplitude of oscillation for a single lift by harmonic analysis, effect of cam profile, the setting up of resonance, and forced spring oscillation with damping.

  11. Rotary spring energy storage

    SciTech Connect

    Cooley, S.

    1981-07-01

    The goal was to design a lightweight system, for bicycles, that can level the input energy requirement (human exertion) in accordance with variations in road load (friction, wind, and grade) and/or to provide a system for regenerative braking, that is, to store energy normally lost in brake pad friction for brief periods until it required for re-acceleration or hill-climbing. The rotary spring, also called the coil, motor, spiral, or power spring is governed by the equations reviewed. Materials used in spring manufacture are briefly discussed, and justification for steel as the design choice of material is given. Torque and power requirements for a bicycle and rider are provided as well as estimated human power output levels. These criteria are examined to define spring size and possible orientations on a bicycle. Patents and designs for coupling the spring to the drive train are discussed.

  12. Structural controls on karstic conduits in a collisional orogen (Sierra de las Nieves, Betic Cordillera, S Spain)

    NASA Astrophysics Data System (ADS)

    Pedrera, A.; Luque-Espinar, J. A.; Martos-Rosillo, S.; Pardo-Igúzquiza, E.; Durán-Valsero, J. J.; Martínez-Moreno, F.; Guardiola-Albert, C.

    2015-06-01

    We characterize the fracture pattern, including both meso-scale joints and macro-scale faults, within the central sector of Sierra de las Nieves (Betic Cordillera, S Spain), which contains one of the largest karstification systems in Europe. Structural data were compared with the direction pattern of the karstic conduit network of the largest caves. Carbonate rocks were deformed in a collisional setting and exposed at the surface since the early Miocene. Normal and normal-oblique faults trending NW-SE to WNW-ESE are the most prominent brittle structures, having formed coevally with shorter NE-SW normal to normal-dextral after the main thrusting phase. In addition, two main open joint sets striking NW-SE and NE-SW developed on a broad scale. Orthogonal normal faults and open joints suggest an extensional setting characterized by horizontal minimum (S3) and intermediate (S2) stress axes of similar magnitudes that intermittently shifted their positions during the middle-to-late Miocene. Vertical water flow coming from direct recharge sectors tends to infiltrate across these high-dipping faults, mainly concentrating at fault intersections, thus favoring sub-vertical conduit formation within the vadose zone. Horizontal paleo-phreatic levels are perched linked to the recent uplift undergone by the sector, giving us the opportunity to analyze the incidence of fractures at the phreatic zone. Joint sets determine the hydraulic anisotropy within the former phreatic levels. Because our study illustrates the primary role of diverse tectonic structures during massive multiphase cave development above and below the water table, it could contribute to better constraining of the models of karstic conduit formation.

  13. Evidence of spring formation and subrosion-induced sinkhole development at Ghor Al-Haditha, Jordan, from repeated close-range photogrammetry

    NASA Astrophysics Data System (ADS)

    Al-Halbouni, Djamil; Eoghan, P. Holohan; Leila, Saberi; Hussam, Alrshdan; Thomas, Walter; Ali, Sawarieh; Torsten, Dahm

    2016-04-01

    and field survey confirms the hypothesis of a large-scale, channelized subterranean water flow in a 3d network of interconnected tubes. This subsurface karstic channel network is hence responsible for sinkhole formation and rapid land subsidence at the Ghor Al-Haditha sinkhole area and perhaps elsewhere around the Dead Sea.

  14. Portrait of a Geothermal Spring, Hunter's Hot Springs, Oregon.

    PubMed

    Castenholz, Richard W

    2015-01-01

    Although alkaline Hunter's Hot Springs in southeastern Oregon has been studied extensively for over 40 years, most of these studies and the subsequent publications were before the advent of molecular methods. However, there are many field observations and laboratory experiments that reveal the major aspects of the phototrophic species composition within various physical and chemical gradients of these springs. Relatively constant temperature boundaries demark the upper boundary of the unicellular cyanobacterium, Synechococcus at 73-74 °C (the world-wide upper limit for photosynthesis), and 68-70 °C the upper limit for Chloroflexus. The upper limit for the cover of the filamentous cyanobacterium, Geitlerinema (Oscillatoria) is at 54-55 °C, and the in situ lower limit at 47-48 °C for all three of these phototrophs due to the upper temperature limit for the grazing ostracod, Thermopsis. The in situ upper limit for the cyanobacteria Pleurocapsa and Calothrix is at ~47-48 °C, which are more grazer-resistant and grazer dependent. All of these demarcations are easily visible in the field. In addition, there is a biosulfide production in some sections of the springs that have a large impact on the microbiology. Most of the temperature and chemical limits have been explained by field and laboratory experiments. PMID:25633225

  15. Environmental and hydrogeological problems in karstic terrains crossed by tunnels: a case study

    NASA Astrophysics Data System (ADS)

    Gisbert, J.; Vallejos, A.; González, A.; Pulido-Bosch, A.

    2009-07-01

    The construction of one of the high-speed railway tunnels between Malaga and Córdoba (South Spain) beneath the Abdalajís mountains occasioned a series of hydrogeological problems with geotechnical and environmental impacts. The double tunnel, 7,300 m in length, runs south to north across several lines of small, calcareous mountains that have a highly complex structure. Beneath the Jurassic limestones lie Triassic clays and evaporites. Overlying the limestones is an essentially marly and limestone-marl Cretaceous series, which culminates with Miocene marls containing some organic matter. These mountains have generated springs that are used for urban water supply and irrigation, as well as drinking fountains in the surrounding villages. The initial water level in the aquifer series varied from 400 to 650 m above sea level. After drilling approximately 2,900 m, and intercepting a fracture zone within the carbonate rocks, a sudden water eruption occurred that reached a peak flow of 800 L/s. After a short while, spring discharges dried up, leading to a public protest. In this paper, we describe the geological and hydrogeological settings, the development of the aquifer as the drilling operation proceeded, the measures adopted and the responses subsequent to completion of the tunnel, including the effect of rainfall on the recovery of water levels. Lastly, a generalized estimate is made of how the system functions, and a forecast is made for recovery of its equilibrium.

  16. SPRING_TANK

    EPA Science Inventory

    This point coverage shows springs and water tanks on Salt River Indian Reservation in Arizona. This coverage was digitized off of USGS 7.5 minute quad maps by the Phoenix office of the Bureau of Indian Affairs.

  17. Harbingers of Spring

    ERIC Educational Resources Information Center

    Serrao, John

    1976-01-01

    Emphasizing the spring migration of frogs, toads, and salamanders to their watery breeding sites, this article presents information on numerous amphibians and suggests both indoor and outdoor educational activities appropriate for elementary and/or early secondary instruction. (JC)

  18. Chemical spring water measurements coupled with 2d u.d.e.c hydromechanical modelling as an investigation methodology of water infiltration influence on large moving rock mass stability : application to the "la clapière" landslide (france, 06).

    NASA Astrophysics Data System (ADS)

    Cappa, F.; Guglielmi, Y.; Soukatchoff, V. M.; Mudry, J.; Bertrand, C.; Charmoille, A.

    2003-04-01

    We present an investigation method of water infiltration influence on Large Moving Rock Mass (LMRM) stability. In the case of huge unstable mountainous slopes, it has been clearly shown that the main driving of instability is gravity and that the major triggering and increasing factor is water located in interstices and fractures of rocks (Noverraz &al., 1998). More particularly, groundwater originates from a localized hydro-mechanical deformation inside fractures that can induce a generalized destabilization of large rock masses (Guglielmi, 1999). However, the understanding of groundwater mechanical effects on landslides and their neighbouring environment is rendered more complex given the large anisotropy of the rock mass as well as the difficulties to apply classic hydrogeological investigation methods in a moving environment. For these reasons, we developped an indirect investigation method based on chemical groundwater measurements coupled with a two-dimensional hydro-mechanical modelling with the Universal Distinct Element Code (UDEC) numerical program, taking the example of the La Clapière landslide (Alpes-Maritimes, France). The methodology we develop firstly establishes a hydro-mechanical conceptual scheme through the analysis of geological, hydrogeological, hydrogeochemistry and landslide velocity measurements. Then, a two-dimensional numerical modelling with UDEC was performed to test the influence of the locations and the intensities of water infiltrations on the hydro-mechanical behaviour of La Clapière’s slope. A geological and hydrogeological analysis reveals a perched saturated zone connected by large conducting-flow fractures to a basal aquifer. The correlations of spring water chemistry data and meteorological events on the slope highlight a large variability of groundwater transits in the slope in time (transit durations of 1 to 21 days) and in space. Infiltration transients correlate with landslide accelerations. Infiltration yields range

  19. Chemical and Isotopic Variability of Spring Discharge: Implications for Groundwater Flow Pathways and Residence Times in the R-aquifer, Grand Canyon, Arizona

    NASA Astrophysics Data System (ADS)

    Brown, C. R.; Springer, A. E.; Hogan, J.; Rice, S. E.

    2008-12-01

    Roaring Springs is the sole supply of potable water to the 4.4 million annual visitors and employees at Grand Canyon National Park. Roaring Springs and other karst-fed springs on the Grand Canyon's North Rim also provide baseflow to the Colorado River and support riparian habitats along tributary canyons. Climate change and proposed changes in land management north of Grand Canyon National Park may dramatically affect the quantity and quality of water discharging from the North Rim springs. These springs are sourced from water recharged on the Kaibab Plateau that travels a minimum of 900 vertical meters through conduits, faults, and fractures before discharging from the R-aquifer, a deep unconfined karstic carbonate aquifer. Stable isotope data, specifically ä18O and ä2H, from spring and precipitation samples were used to indicate the seasonality and location of recharge. Roaring Springs shows a distinct seasonal variation in isotopic signature with summer values more depleted in 2H and more enriched in 18O than winter values. Major cation/anion analyses along with other geochemical signatures will be assessed to interpret groundwater flowpaths and residence times, and to put North Rim springs in a regional context with other Grand Canyon springs. Specifically, evidence for seasonal transition between saturated and unsaturated conduit flow may be accentuated by variations in isotopic and chemical signatures in North Rim spring discharge. These results will represent the most comprehensive hydrologic dataset for North Rim springs and will be used to develop a conceptual groundwater flow model with the United States Geological Survey's new Conduit Flow Process package. Previous conceptual groundwater flow models for the area have yet to take into account the possibility of turbulent flow through karst conduits.

  20. Segmented tubular cushion springs and spring assembly

    NASA Technical Reports Server (NTRS)

    Haslim, Leonard A. (Inventor)

    1988-01-01

    A spring (10) includes a tube (12) having an elliptical cross section, with the greater axial dimension (22) extending laterally and the lesser axial dimension (24) extending vertically. A plurality of cuts (20) in the form of slots passing through most of a wall of the tube (12) extend perpendicularly to a longitudinal axis (16) extending along the tube (12). An uncut portion (26) of the tube wall extends along the tube (12) for bonding or fastening the tube to a suitable base, such as a bottom (28) of a seat cushion (30).

  1. Segmented tubular cushion springs and spring assembly

    NASA Technical Reports Server (NTRS)

    Haslim, L. A. (Inventor)

    1985-01-01

    A spring which includes a tube with an elliptical cross section, with the greater axial dimension extending laterally and the lesser axial dimension extending vertically is disclosed. A plurality of cuts in the form of slots passing through most of a wall of the tube extend perpendiculary to a longitudinal axis extending along the tube. An uncut portion of the tube wall extends along the tube for bonding or fastening the tube to a suitable base, such as a bottom of a seat cushion.

  2. Geoarchaeology of the karstic area of Mirambello, North-East Crete (Greece): palaeoenvironmental investigations and human settlement implications

    NASA Astrophysics Data System (ADS)

    Ghilardi, M.; Kunesch, S.; Robert, V.; Farnoux, A.; Wurmser, H.

    2009-04-01

    The present work aims to detail the preliminary researches dealing with the geomorphologic, topographic and archaeological setting from two major settlements located in north east Crete. The project undertook by the French school of Archaeology in Athens aims to reconstruct the palaeoenvironmental evolution of the whole area during the last millennia. Fieldworks, including coring, had already been done in August 2006, April 2007 and September 2008; we propose to present the main results. The settlements of Latô and Dreros belong to the area of Mirambello characterized by its spectacular karstic processes and landforms, different karstic depressions with different size can be identified and classified into Dolines and Poljés. As far as the archaeological interest is concerned, villages and cities were occupied during the hellenestic period; several remains are still present around and inside these depressions. Using a G.I.S., the first step consisted in establishing a local geomorphological mapping, taking into account the geological background and the historical occupation of the area. The second step consisted in establishing topographic cross sections of the doline, where the ancient settlement of Latô is located, based on various DGPS surveys. Several questions concerning the occupation of this depression arose : how and for which reasons people decided to leave close to this specific landform ? Which type of activities (farming, grazing, cultivation…) existed and did they were related with natural resources exploitation ? A project associating the local greek archaeological services (Ephoria of Aghios Nikolaos, Director Ms. Apostolakou), the mayor of Nea Polis, the University of Paris 12 (GEONAT EA 435) and the French School of Athens tries to depict the historical evolution of the landscape. Four boreholes (up to a maximum depth of 5 meters) had been drilled in the poljé of Dreros and in a doline situated 1 km away from the ancient settlement of Lat

  3. Spring polar ozone behavior

    NASA Technical Reports Server (NTRS)

    Aikin, Arthur C.

    1992-01-01

    Understanding of the springtime behavior of polar stratospheric ozone as of mid 1990 is summarized. Heterogeneous reactions on polar stratospheric clouds as hypothesis for ozone loss are considered and a simplified description of the behavior of Antarctic ozone in winter and spring is given. Evidence that the situation is more complicated than described by the theory is produced. Many unresolved scientific issues remain and some of the most important problems are identified. Ozone changes each spring since 1979 have clearly established for the first time that man made chlorine compounds influence stratospheric ozone. Long before important advances in satellite and in situ investigations, it was Dobson's decision to place a total ozone measuring spectrometer at Halley Bay in Antarctica during the International Geophysical Year and subsequent continuous monitoring which led to the discovery that ozone was being destroyed each spring by chlorine processed by polar stratospheric clouds.

  4. Iron, cadmium, and chromium in seagrass (Thalassia testudinum) from a coastal nature reserve in karstic Yucatán.

    PubMed

    Avelar, Mayra; Bonilla-Heredia, Blanca; Merino-Ibarra, Martín; Herrera-Silveira, Jorge A; Ramirez, Javier; Rosas, Humberto; Valdespino, Job; Carricart-Ganivet, Juan P; Martínez, Ana

    2013-09-01

    The management of protected areas in karstic regions is a challenge because flooded cave systems form there and provide underground hydrological conducts that may link different zones. As a consequence, affectations to the protected areas can possibly occur as a consequence of human activities in remote areas and may therefore pass undetected. Thus, the monitoring of possible contaminants in these regions is becoming imperative. In this work, we analyze the concentration of essential (iron) and non-essential metals (cadmium and chromium) in the seagrass Thalassia testudinum that grows in Yalahau Lagoon, located in a near-to-pristine protected area of the Yucatán Peninsula, close to the rapidly developing touristic belt of the Mexican Caribbean. Salinity and silicate patterns show that Yalahau is an evaporation lagoon, where groundwater discharge is important. High iron (> 400 μg/g), cadmium (>4 μg/g), and chromium (≈ 1 μg/g) concentrations were found in the area of highest groundwater input of the lagoon. High levels (5.1 μg/g) were also found near the town dump. In the rest of the sampling sites, metal concentrations remained near to background levels as estimated from other works. Temporal changes of concentrations in the seagrass tissues show also a local input and an input from the groundwater that could provoke an environmental problem in the Yalahau Lagoon in the near future. PMID:23404548

  5. Diversity of freshwater Epsilonproteobacteria and dark inorganic carbon fixation in the sulphidic redoxcline of a meromictic karstic lake.

    PubMed

    Noguerola, Imma; Picazo, Antonio; Llirós, Marc; Camacho, Antonio; Borrego, Carles M

    2015-07-01

    Sulfidic redoxclines are a suitable niche for the growth and activity of different chemo- and photolithotrophic sulphide-oxidizing microbial groups such as the Epsilonproteobacteria and the green sulfur bacteria (GSB). We have investigated the diversity, abundance and contribution to inorganic carbon uptake of Epsilonproteobacteria in a meromictic basin of Lake Banyoles. CARD-FISH counts revealed that Epsilonproteobacteria were prevalent at the redoxcline in winter (maximum abundance of 2 × 10(6) cells mL(-1), ≈60% of total cells) but they were nearly absent in summer, when GSB bloomed. This seasonal trend was supported by 16S rRNA gene pyrotag datasets, which revealed that the epsilonproteobacterial community was mainly composed of a member of the genus Arcobacter. In situ incubations using NaH(14)CO3 and MAR-CARD-FISH observations showed that this population assimilated CO2 in the dark, likely being mainly responsible for the autotrophic activity at the redoxcline in winter. Clone libraries targeting the aclB gene provided additional evidence of the potential capacity of these epsilonproteobacteria to fix carbon via rTCA cycle. Our data reinforce the key role of Epsilonproteobacteria in linking carbon and sulphur cycles, extend their influence to freshwater karstic lakes and raise questions about the actual contribution of chemolithotrophy at their redoxcline and euxinic water compartments. PMID:26195601

  6. Analysis of transport connectivity in karstic aquifers spanned by 3D conduit networks

    NASA Astrophysics Data System (ADS)

    Ronayne, M. J.

    2013-12-01

    Karst aquifers are characterized by interconnected conduits that behave as structural pathways for groundwater and solutes. This modeling study assesses the influence of conduit network geometry on solute transport behavior within karst systems. Synthetic karst aquifers containing 3D conduit networks were considered. Networks of varying complexity were generated using a directed percolation model. Flow and transport simulations were conducted for each synthetic aquifer by modeling the conduits as discretized high-permeability features within a uniform matrix material. Transport connectivity and dispersive properties were evaluated using statistical moments of the solute arrival time distribution at the downgradient conduit outlet (karst spring). In addition, a new connectivity metric that quantifies solute residence time within conduits was considered. Results show that a more complex network leads to enhanced mixing between the conduit and matrix domains, which has the effect of reducing transport connectivity. This modeling study illustrates how typically available transport data (e.g., solute breakthrough curves at the conduit outlet) may reveal information about the internal network structure, thus providing guidance for future inverse modeling.

  7. Spring black stem

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spring black stem is the most destructive alfalfa diseases in temperate regions of the U.S., Canada, Australia, and countries of Europe, Asia, and South America. The disease causes serious yield losses by reducing canopy dry matter and also decreases seed weight and crown and root mass. Forage qua...

  8. The News. Spring 2006

    ERIC Educational Resources Information Center

    Giles, Ray, Ed.

    2006-01-01

    This Spring issue of the quarterly newsletter of the Community College League of California contains the following articles: (1) Enrollment Drops; Fees to Blame?; (2) Senate's Grad Proposal Triggers Debate on Mission, Access; (3) Compton Decision has Affected Perceptions of Commission (discussion with Barbara Beno); (4) Dynamic New Architectural…

  9. Atascocita Springs Elementary School

    ERIC Educational Resources Information Center

    Nigaglioni, Irene; Yocham, Deborah

    2011-01-01

    With the significant amount of time invested in researching the best techniques for delivering instruction to their students, Humble ISD is always on the forefront of education. Taking the recommendations of their active and vocal community groups, the district embarked in the design of the 26th elementary school, Atascocita Springs Elementary…

  10. Planar torsion spring

    NASA Technical Reports Server (NTRS)

    Ihrke, Chris A. (Inventor); Parsons, Adam H. (Inventor); Mehling, Joshua S. (Inventor); Griffith, Bryan Kristian (Inventor)

    2012-01-01

    A torsion spring comprises an inner mounting segment. An outer mounting segment is located concentrically around the inner mounting segment. A plurality of splines extends from the inner mounting segment to the outer mounting segment. At least a portion of each spline extends generally annularly around the inner mounting segment.

  11. Energy Matters - Spring 2002

    SciTech Connect

    2002-03-01

    Quarterly newsletter from DOE's Industrial Technologies Program to promote the use of energy-efficient industrial systems. The focus of the Spring 2002 Issue of Energy Matters focuses on premium energy efficiency systems, with articles on new gas technologies, steam efficiency, the Augusta Newsprint Showcase, and more.

  12. A Quadratic Spring Equation

    ERIC Educational Resources Information Center

    Fay, Temple H.

    2010-01-01

    Through numerical investigations, we study examples of the forced quadratic spring equation [image omitted]. By performing trial-and-error numerical experiments, we demonstrate the existence of stability boundaries in the phase plane indicating initial conditions yielding bounded solutions, investigate the resonance boundary in the [omega]…

  13. Editors' Spring Picks

    ERIC Educational Resources Information Center

    Library Journal, 2011

    2011-01-01

    While they do not represent the rainbow of reading tastes American public libraries accommodate, Book Review editors are a wildly eclectic bunch. One look at their bedside tables and ereaders would reveal very little crossover. This article highlights an eclectic array of spring offerings ranging from print books to an audiobook to ebook apps. It…

  14. Echoes of Spring Valley.

    ERIC Educational Resources Information Center

    Boyken, J. Clarine J.

    Designed to preserve the rich heritage of the rural school system which passed from the education scene in the 1930's and 1940's, this narrative, part history and part nostalgia, describes the author's own elementary education and the secure community life centered in the one room Spring Valley School in Hamilton County, Iowa, in the early decades…

  15. Registration of 'Prevail' hard red spring wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grower and end-user acceptance of new Hard Red Spring Wheat (HRSW; Triticum aestivum L.) cultivars is largely contingent upon satisfactory agronomic performance, end-use quality potential, and disease resistance levels. Additional characteristics, such as desirable plant height, can also contribute...

  16. Registration of 'Advance' Hard Red Spring Wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grower and end-user acceptance of new hard red spring wheat (HRSW; Triticum aestivum L.) cultivars is largely contingent on satisfactory agronomic performance, end-use quality potential, and disease resistance levels. Additional characteristics, such as desirable plant height, can also help to maxi...

  17. 9. CONTEXTUAL VIEW SOUTHSOUTHEAST TOWARDS SPRING SITE. SPRING LEFT CORNER. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. CONTEXTUAL VIEW SOUTH-SOUTHEAST TOWARDS SPRING SITE. SPRING LEFT CORNER. - Juniata Mill Complex, 22.5 miles Southwest of Hawthorne, between Aurora Crater & Aurora Peak, Hawthorne, Mineral County, NV

  18. Spring- And Air-Suspension Mechanism For Testing Structures

    NASA Technical Reports Server (NTRS)

    Woodard, Stanley E.

    1994-01-01

    Spring-and air-suspension mechanism supports weight of one end of test structure, yet allows that end to move almost completely unhindered as though it were weightless and not attached to suspension. Mechanisms of this type called "zero-spring-rate mechanisms" (ZSRM's) because they support structure in manner of spring suspension exhibiting approximately zero stiffness (zero spring rate) within some range of motion about nominal equilibrium or central support position. This suspension mechanism does not include overhead cables, which necessitate large amounts of overhead clearance and overhead support structures: suspension mechanism more compact (much smaller than structure) and supports structure from below.

  19. Chemical and isotopic composition of water from thermal springs and mineral springs of Washington

    USGS Publications Warehouse

    Mariner, R.H.; Presser, T.S.; Evans, William C.

    1982-01-01

    Water from thermal springs of Washington range in chemical composition from dilute NaHC03, to moderately saline C02-charged NaHC03-Cl waters. St. Martin 's Hot Spring which discharges a slightly saline NaCl water, is the notable exception. Mineral springs generally discharge a moderately saline C02-charged NaHC03-Cl water. The dilute Na-HC03 waters are generally associated with granite. The warm to hot waters charged with C02 issue on or near the large stratovolcanoes and many of the mineral springs also occur near the large volcanoes. The dilute waters have oxygen isotopic compositions which indicate relatively little water-rock exchange. The C02-charged waters are usually more enriched in oxygen-18 due to more extensive water-rock reaction. Carbon-13 in the C02-charged thermal waters is more depleted (-10 to -12 permil) than in the cold C02-charged soda springs (-2 to -8 permil) which are also scattered throughout the Cascades. The hot and cold C02-charged waters are supersaturated with respect to CaC03, but only the hot springs are actively depositing CaC03. Baker, Gamma, Sulphur , and Ohanapecosh seem to be associated with thermal aquifers of more than 100C. (USGS)

  20. Studying Springs in Series Using a Single Spring

    ERIC Educational Resources Information Center

    Serna, Juan D.; Joshi, Amitabh

    2011-01-01

    Springs are used for a wide range of applications in physics and engineering. Possibly, one of their most common uses is to study the nature of restoring forces in oscillatory systems. While experiments that verify Hooke's law using springs are abundant in the physics literature, those that explore the combination of several springs together are…

  1. The nature of annual lamination in flowstones from non-karstic fractures, Vinschgau (northern Italy)

    NASA Astrophysics Data System (ADS)

    Koltai, Gabriella; Spötl, Christoph; Cheng, Hai

    2016-04-01

    The Vinschgau is an inneralpine valley in the Southern Alps. The region is built up by metamorphic rocks characterised by a high degree of tectonic deformation. Although karst is not known in the Vinschgau, calcite and calcite-aragonite flowstones are deposited from supersaturated groundwater along the South-facing mountain slope as a result of strong evaporation (Spötl et al. 2002). Flowstone precipitation is strongly connected to fracture openings created by deep-seated gravitational slope deformations. The carbonate-depositing springs are part of an extended groundwater system controlled by the geometry of the deep-seated gravitational slope deformation. Although the mean residence time of the groundwater is up to several decades (Spötl et al. 2002), a few flowstones show macroscopically visible laminae whose annual origin is confirmed by U-Th dating. These laminae are composed of a darker and a lighter sublamina forming couplets whose thickness ranges from 0.2 to 2 mm. In thin section, the darker sublaminae show a higher abundance of opaque particles, whereas the light ones are inclusion-poor. Strong epifluorescence confirms the organic origin of these dark inclusions. The crystal fabric, dominated by the fascicular-optic type, shows no change across lamina boundaries. Laminated calcite shows δ18O oscillations with an amplitude of up to 1.4 permil. These oscillations are also present in unlaminated calcite, albeit at much smaller amplitude. δ13C lacks such a regular pattern in laminated samples, and only shows small variations which do not correlate with δ18O in a consistent way. Changes in δ13C show smaller amplitudes than δ18O. The extent of correlation between petrographic laminae and the stable isotopes varies both in time and space. During the late Younger Dryas darker sublaminae mostly coincide with δ18O lows, whereas in the Mid-Holocene they usually correlate with isotope highs. These data reflect the high degree of heterogeneity of such fracture

  2. Thermal springs in Lake Baikal

    SciTech Connect

    Shanks, W.C. III; Callender, E. )

    1992-06-01

    Pore waters extracted from sediment cores were analyzed for their oxygen and hydrogen isotopic compositions and major ion chemistry to determine the source of water from a vent area for diffuse lake-bottom thermal springs or seeps in Frolikha Bay, northeastern Lake Baikal. The {delta}{sup 18}O values of pore waters range from {minus}15.2{per thousand} to {minus}16.7{per thousand}, and {delta}D values range from {minus}119{per thousand} to {minus}126{per thousand} (both isotopes determined relative to standard mean ocean water (SMOW)). Bottom water in Lake Baikal has a {delta}{sup 18}O value of {minus}5.6{per thousand} and a {delta}D values of {minus}120{per thousand}. Pore waters in the vent area are significantly enriched in Mg, K, Ca, and especially Na and have the lowest {delta}D and {delta}{sup 18}O values; these pore waters are isotopically and chemically distinct from pore waters in other, more typical parts of the lake. The pore-water isotopic data fall on a local meteoric water line, and covariations in water isotopes and chemistry are not consistent with evaporation or hydrothermal water-rock interaction. The thermal springs represent discharging meteoric waters that have been gently heated during subsurface circulation and are largely unaltered isotopically. Chemical variations are most likely due to dissolution of subsurface evaporites.

  3. Hot Spring Metagenomics

    PubMed Central

    López-López, Olalla; Cerdán, María Esperanza; González-Siso, María Isabel

    2013-01-01

    Hot springs have been investigated since the XIX century, but isolation and examination of their thermophilic microbial inhabitants did not start until the 1950s. Many thermophilic microorganisms and their viruses have since been discovered, although the real complexity of thermal communities was envisaged when research based on PCR amplification of the 16S rRNA genes arose. Thereafter, the possibility of cloning and sequencing the total environmental DNA, defined as metagenome, and the study of the genes rescued in the metagenomic libraries and assemblies made it possible to gain a more comprehensive understanding of microbial communities—their diversity, structure, the interactions existing between their components, and the factors shaping the nature of these communities. In the last decade, hot springs have been a source of thermophilic enzymes of industrial interest, encouraging further study of the poorly understood diversity of microbial life in these habitats. PMID:25369743

  4. The joys of spring.

    PubMed

    Riby, Leigh M

    2013-01-01

    This study used Vivaldi's Four Seasons, an extraordinary example of program music, to explore the consequence of music exposure on cognitive event-related potentials (ERPs). Seventeen participants performed a three-stimulus visual odd-ball task while ERPs were recorded. Participants were required to differentiate between a rare target stimulus (to elicit a memory updating component; P3b), a rare novel stimulus (to elicit a novelty attention component; P3a), and a frequent nontarget stimulus. During task performance participants listened to the four concertos: Spring, Summer, Autumn, and Winter in comparison to a silent control condition. Additionally, the three movements of each concerto have a fast, slow, fast structure that enabled examination of the impact of tempo. The data revealed that "Spring," particularly the well-recognized, vibrant, emotive, and uplifting first movement, had the ability to enhance mental alertness and brain measures of attention and memory. PMID:22851380

  5. Spring operated accelerator and constant force spring mechanism therefor

    NASA Technical Reports Server (NTRS)

    Shillinger, G. L., Jr. (Inventor)

    1977-01-01

    A spring assembly consisting of an elongate piece of flat spring material formed into a spiral configuration and a free running spool in circumscribing relation to which this spring is disposed was developed. The spring has a distal end that is externally accessible so that when the distal end is drawn along a path, the spring unwinds against a restoring force present in the portion of the spring that resides in a transition region between a relatively straight condition on the path and a fully wound condition on the spool. When the distal end is released, the distal end is accelerated toward the spool by the force existing at the transition region which force is proportional to the cross-sectional area of the spring.

  6. Spring magnet films.

    SciTech Connect

    Bader, S. D.; Fullerton, E. E.; Gornakov, V. S.; Inomata, A.; Jiang, J. S.; Nikitenko, V. I.; Shapiro, A. J.; Shull, R. D.; Sowers, C. H.

    1999-03-29

    The properties of exchange-spring-coupled bilayer and superlattice films are highlighted for Sm-Co hard magnet and Fe or Co soft magnet layers. The hexagonal Sm-Co is grown via magnetron sputtering in a- and b-axis epitaxial orientations. In both cases the c-axis, in the film plane, is the easy axis of magnetization. Trends in coercivity with film thickness are established and related to the respective microstructure of the two orientations. The magnetization reversal process for the bilayers is examined by magnetometry and magneto-optical imaging, as well as by simulations that utilize a one-dimensional model to provide the spin configuration for each atomic layer. The Fe magnetization is pinned to that of the Sm-Co at the interface, and reversal proceeds via a progressive twisting of the Fe magnetization. The Fe demagnetization curves are reversible as expected for a spring magnet. Comparison of experiment and simulations indicates that the spring magnet behavior can be understood from the intrinsic properties of the hard and soft layers. Estimated are made of the ultimate gain in performance that can potentially be realized in this system.

  7. Actinobacteria Isolated from an Underground Lake and Moonmilk Speleothem from the Biggest Conglomeratic Karstic Cave in Siberia as Sources of Novel Biologically Active Compounds.

    PubMed

    Axenov-Gribanov, Denis V; Axenov-Gibanov, Denis V; Voytsekhovskaya, Irina V; Tokovenko, Bogdan T; Protasov, Eugeniy S; Gamaiunov, Stanislav V; Rebets, Yuriy V; Luzhetskyy, Andriy N; Timofeyev, Maxim A

    2016-01-01

    Actinobacteria isolated from unstudied ecosystems are one of the most interesting and promising sources of novel biologically active compounds. Cave ecosystems are unusual and rarely studied. Here, we report the isolation and characterization of ten new actinobacteria strains isolated from an ancient underground lake and moonmilk speleothem from the biggest conglomeratic karstic cave in Siberia with a focus on the biological activity of the obtained strains and the metabolite dereplication of one active strain. Streptomyces genera isolates from moonmilk speleothem demonstrated antibacterial and antifungal activities. Some of the strains were able to inhibit the growth of pathogenic Candida albicans. PMID:26901168

  8. Actinobacteria Isolated from an Underground Lake and Moonmilk Speleothem from the Biggest Conglomeratic Karstic Cave in Siberia as Sources of Novel Biologically Active Compounds

    PubMed Central

    Tokovenko, Bogdan T.; Protasov, Eugeniy S.; Gamaiunov, Stanislav V.; Rebets, Yuriy V.; Luzhetskyy, Andriy N.; Timofeyev, Maxim A.

    2016-01-01

    Actinobacteria isolated from unstudied ecosystems are one of the most interesting and promising sources of novel biologically active compounds. Cave ecosystems are unusual and rarely studied. Here, we report the isolation and characterization of ten new actinobacteria strains isolated from an ancient underground lake and moonmilk speleothem from the biggest conglomeratic karstic cave in Siberia with a focus on the biological activity of the obtained strains and the metabolite dereplication of one active strain. Streptomyces genera isolates from moonmilk speleothem demonstrated antibacterial and antifungal activities. Some of the strains were able to inhibit the growth of pathogenic Candida albicans. PMID:26901168

  9. Buckling analysis of planar compression micro-springs

    SciTech Connect

    Zhang, Jing; Sui, Li; Shi, Gengchen

    2015-04-15

    Large compression deformation causes micro-springs buckling and loss of load capacity. We analyzed the impact of structural parameters and boundary conditions for planar micro-springs, and obtained the change rules for the two factors that affect buckling. A formula for critical buckling deformation of micro-springs under compressive load was derived based on elastic thin plate theory. Results from this formula were compared with finite element analysis results but these did not always correlate. Therefore, finite element analysis is necessary for micro-spring buckling analysis. We studied the variation of micro-spring critical buckling deformation caused by four structural parameters using ANSYS software under two constraint conditions. The simulation results show that when an x-direction constraint is added, the critical buckling deformation increases by 32.3-297.9%. The critical buckling deformation decreases with increase in micro-spring arc radius or section width and increases with increase in micro-spring thickness or straight beam width. We conducted experiments to confirm the simulation results, and the experimental and simulation trends were found to agree. Buckling analysis of the micro-spring establishes a theoretical foundation for optimizing micro-spring structural parameters and constraint conditions to maximize the critical buckling load.

  10. Lomonosov In Spring

    NASA Technical Reports Server (NTRS)

    2004-01-01

    26 September 2004 This blue wide angle Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the frost-covered rims of Lomonosov Crater in late martian spring. At the north (top) end of the image, low, ground-hugging fog can be seen in association with the retreating seasonal polar cap. Lomonosov Crater is about 150 km (93 mi) in diameter and located at 65oN, 9oW. The image is illuminated by sunlight from the lower left.

  11. Fun with Automobile Springs

    NASA Astrophysics Data System (ADS)

    Fritsch, Klaus

    2006-10-01

    Simple measurements on car suspension systems and their analysis can raise student interest in the elementary discussion of the behavior of springs in oscillating systems. To understand these complicated oscillating systems and to interpret measurements properly, models may be used. Students find out how to make approximations and extract useful information from marginal data using common sense, basic physics, and simple software tools. Basic experiments on a physical model of a car suspension and on a passenger car, as well as the analysis of the data, will be presented. In particular, a value of the bounce mode frequency of a car was obtained using several approaches.

  12. Characterisation of the transmissivity field of a fractured and karstic aquifer, Southern France

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoguang; Jardani, Abderrahim; Jourde, Hervé; Lonergan, Lidia; Cosgrove, John; Gosselin, Olivier; Massonnat, Gérard

    2016-01-01

    Geological and hydrological data collected at the Terrieu experimental site north of Montpellier, in a confined carbonate aquifer indicates that both fracture clusters and a major bedding plane form the main flow paths of this highly heterogeneous karst aquifer. However, characterising the geometry and spatial location of the main flow channels and estimating their flow properties remain difficult. These challenges can be addressed by solving an inverse problem using the available hydraulic head data recorded during a set of interference pumping tests. We first constructed a 2D equivalent porous medium model to represent the test site domain and then employed regular zoning parameterisation, on which the inverse modelling was performed. Because we aim to resolve the fine-scale characteristics of the transmissivity field, the problem undertaken is essentially a large-scale inverse model, i.e. the dimension of the unknown parameters is high. In order to deal with the high computational demands in such a large-scale inverse problem, a gradient-based, non-linear algorithm (SNOPT) was used to estimate the transmissivity field on the experimental site scale through the inversion of steady-state, hydraulic head measurements recorded at 22 boreholes during 8 sequential cross-hole pumping tests. We used the data from outcrops, borehole fracture measurements and interpretations of inter-well connectivities from interference test responses as initial models to trigger the inversion. Constraints for hydraulic conductivities, based on analytical interpretations of pumping tests, were also added to the inversion models. In addition, the efficiency of the adopted inverse algorithm enables us to increase dramatically the number of unknown parameters to investigate the influence of elementary discretisation on the reconstruction of the transmissivity fields in both synthetic and field studies. By following the above approach, transmissivity fields that produce similar hydrodynamic

  13. A method for the stochastic modeling of karstic systems accounting for geophysical data: an example of application in the region of Tulum, Yucatan Peninsula (Mexico)

    NASA Astrophysics Data System (ADS)

    Vuilleumier, C.; Borghi, A.; Renard, P.; Ottowitz, D.; Schiller, A.; Supper, R.; Cornaton, F.

    2013-05-01

    The eastern coast of the Yucatan Peninsula, Mexico, contains one of the most developed karst systems in the world. This natural wonder is undergoing increasing pollution threat due to rapid economic development in the region of Tulum, together with a lack of wastewater treatment facilities. A preliminary numerical model has been developed to assess the vulnerability of the resource. Maps of explored caves have been completed using data from two airborne geophysical campaigns. These electromagnetic measurements allow for the mapping of unexplored karstic conduits. The completion of the network map is achieved through a stochastic pseudo-genetic karst simulator, previously developed but adapted as part of this study to account for the geophysical data. Together with the cave mapping by speleologists, the simulated networks are integrated into the finite-element flow-model mesh as pipe networks where turbulent flow is modeled. The calibration of the karstic network parameters (density, radius of the conduits) is conducted through a comparison with measured piezometric levels. Although the proposed model shows great uncertainty, it reproduces realistically the heterogeneous flow of the aquifer. Simulated velocities in conduits are greater than 1 cm s-1, suggesting that the reinjection of Tulum wastewater constitutes a pollution risk for the nearby ecosystems.

  14. Diversity of Vibrio spp in Karstic Coastal Marshes in the Yucatan Peninsula

    PubMed Central

    2015-01-01

    Coastal bodies of water formed by the combination of seawater, underground rivers and rainwater comprise the systems with the greatest solar energy flow and biomass production on the planet. These characteristics make them reservoirs for a large number species, mainly microorganisms. Bacteria of the genus Vibrio are natural inhabitants of these environments and their presence is determined by variations in the nutrient, temperature and salinity cycles generated by the seasonal hydrologic behavior of these lagoon systems. This study determined the diversity of the genus Vibrio in 4 coastal bodies of water on the Yucatan Peninsula (Celestun Lagoon, Chelem Lagoon, Rosada Lagoon and Sabancuy Estuary). Using the molecular technique of 454 pyrosequencing, DNA extracted from water samples was analyzed and 32,807 reads were obtained belonging to over 20 culturable species of the genus Vibrio and related genera. OTU (operational taxonomic unit) richness and Chao2 and Shannon Weaver diversity indices were obtained with the database from this technique. Physicochemical and environmental parameters were determined and correlated with Vibrio diversity measured in OTUs. PMID:26252792

  15. Multidisciplinary work on barium contamination of the karstic upper Kupa River drainage basin (Croatia and Slovenia); calling for watershed management.

    PubMed

    Francisković-Bilinski, S; Bilinski, H; Grbac, R; Zunić, J; Necemer, M; Hanzel, D

    2007-02-01

    studies has been highlighted. A preliminary study of diseases diagnosed in Lokve shows that about 18% of the total inhabitants have serious medical problems. Diseases of the circulatory system, endocrine, nutritional, and metabolic diseases, neoplasms, and respiratory diseases predominate. This paper calls for further multidisciplinary research on the health effects of barium and trace elements, as well as for bioremediation of contaminated gardens and for watershed management of vulnerable karstic aquifers. PMID:17203367

  16. Abiotic Dissolved Organic Matter-Mineral Interaction in the Karstic Floridan Aquifer

    NASA Astrophysics Data System (ADS)

    Jin, J.; Zimmerman, A.

    2007-12-01

    Dissolved organic matter (DOM)-mineral interaction (e.g. adsorption, desorption, mineral dissolution) in groundwater is a significant factor controlling geochemical, environmental and microbial processes and may be helpful in efforts to track groundwater sources or contaminant fate. Despite its importance, the dynamics and consequences of these abiotic interactions remain poorly understood, largely due to the inaccessibility and heterogeneity of the subsurface, as well as the chemical complexity of DOM. This study models the OM-mineral interactions that takes place in the Floridan aquifer through laboratory adsorption-desorption experiments using DOM (groundwater, river water, soil extracts) and carbonate minerals (calcite, dolomite) collected in north Florida. High performance liquid chromatography-size exclusion chromatography (HPLC-SEC) and UV-fluorescence excitation-emission matrix (EEM) spectrophotometry was used to examine the organic compound types exhibiting preferential affinity for carbonate minerals. Our results show that the DOM-carbonate adsorption/desorption isotherms are well described by the Freundlich model. Freundlich exponents (average value: 0.6488) less than one indicated a filling of adsorption sites. Minerals from Ocala tend to have higher adsorption affinity as well as adsorption capacity than those from Suwannee River Basin; however, both were found to have mineral dissolution. Two fluorescent signals, indicative of a fulvic-like (at excitation wavelength 295-310 nm, emission 400-420 nm) and a protein-like (275/345nm) moiety, were detected in DOM. A reduction in the fulvic-like peak intensity occurred following carbonate adsorption while the protein-like peaks remain almost unchanged indicating the preferential adsorption of fulvic acids. HPLC-SEC results (DOM properties as a function of molecular weight) will be discussed. The chemical properties of DOM in environmental groundwater samples will also be presented and evaluated in light of

  17. Gravity for Detecting Caves: Airborne and Terrestrial Simulations Based on a Comprehensive Karstic Cave Benchmark

    NASA Astrophysics Data System (ADS)

    Braitenberg, Carla; Sampietro, Daniele; Pivetta, Tommaso; Zuliani, David; Barbagallo, Alfio; Fabris, Paolo; Rossi, Lorenzo; Fabbri, Julius; Mansi, Ahmed Hamdi

    2016-04-01

    Underground caves bear a natural hazard due to their possible evolution into a sink hole. Mapping of all existing caves could be useful for general civil usages as natural deposits or tourism and sports. Natural caves exist globally and are typical in karst areas. We investigate the resolution power of modern gravity campaigns to systematically detect all void caves of a minimum size in a given area. Both aerogravity and terrestrial acquisitions are considered. Positioning of the gravity station is fastest with GNSS methods the performance of which is investigated. The estimates are based on a benchmark cave of which the geometry is known precisely through a laser-scan survey. The cave is the Grotta Gigante cave in NE Italy in the classic karst. The gravity acquisition is discussed, where heights have been acquired with dual-frequency geodetic GNSS receivers and Total Station. Height acquisitions with non-geodetic low-cost receivers are shown to be useful, although the error on the gravity field is larger. The cave produces a signal of -1.5 × 10-5 m/s2, with a clear elliptic geometry. We analyze feasibility of airborne gravity acquisitions for the purpose of systematically mapping void caves. It is found that observations from fixed wing aircraft cannot resolve the caves, but observations from slower and low-flying helicopters or drones do. In order to detect the presence of caves the size of the benchmark cave, systematic terrestrial acquisitions require a density of three stations on square 500 by 500 m2 tiles. The question has a large impact on civil and environmental purposes, since it will allow planning of urban development at a safe distance from subsurface caves. The survey shows that a systematic coverage of the karst would have the benefit to recover the position of all of the greater existing void caves.

  18. Hazard connected to tunnel construction in Mt Stena karstic area (Rosandra Valley, Classical Karst)

    NASA Astrophysics Data System (ADS)

    Cucchi, F.; Boschin, W.; Visintin, L.; Zini, L.

    2009-04-01

    Rosandra Valley -a unique geomorphological environment- is located in the western side of the Classical Karst plateau. This deep limestone gorge is crossed by a stream that is fed by a large basin located in Slovenia. Rosandra Valley is the only example of Classical Karst river valley with surface hydrography; the torrent digs a deep gully into the rock, rich in rapids, swirl holes, small waterfalls, enclosed meanders and basins; here, the first seepage phenomena occur, and part of the water feeds the underground aquifer. Rosandra Valley is theatre to complex structural situation; the NE slope culminates in the structure of Mt Stena, a limestone tectonic scale located between two faults and firmly rooted in the karst platform. Tectonics is quite important for the development of deep karst in this area; Mt Stena, in particular, hosts a comprehensive net of articulated and diversely shaped caves, basically organised on several levels, which stretches over a total of 9,000 metres, bearing testimony to ancient geological and hydrogeological origins. The deepest areas of the system reach a suspended aquifer that is probably sustained by an overthrust and placed about 100 meters above Rosandra torrent underground aquifer. During feasibility studies about Trieste-Divača high velocity railway link, interaction between project and karst features was examined; in fact the proximity of proposal project and Mt Stena karst system suggest to improve the knowledge related to karst and hydrogeological aspects of the massif. Compatibly with the project requirements, risk of voids intersection and water contamination were analyzed. In fact the Mt Stena suspended aquifer partially feeds Rosandra torrent which flows in a protected natural area. Karst features were represented in a 3D model in order to better understand the spatial relationship between railway project and karst system.

  19. Geothermal resource assessment of Idaho Springs, Colorado. Resource series 16

    SciTech Connect

    Repplier, F.N.; Zacharakis, T.G.; Ringrose, C.D.

    1982-01-01

    Located in the Front Range of the Rocky Mountains approximately 30 miles west of Denver, in the community of Idaho Springs, are a series of thermal springs and wells. The temperature of these waters ranges from a low of 68/sup 0/F (20/sup 0/C) to a high of 127/sup 0/F (53/sup 0/C). To define the hydrothermal conditions of the Idaho Springs region in 1980, an investigation consisting of electrical geophysical surveys, soil mercury geochemical surveys, and reconnaissance geological and hydrogeological investigations was made. Due to topographic and cultural restrictions, the investigation was limited to the immediate area surrounding the thermal springs at the Indian Springs Resort. The bedrock of the region is faulted and fractured metamorphosed Precambrian gneisses and schists, locally intruded by Tertiary age plutons and dikes. The investigation showed that the thermal waters most likely are fault controlled and the thermal area does not have a large areal extent.

  20. Peatland Structural Controls on Spring Distribution

    NASA Astrophysics Data System (ADS)

    Hare, D. K.; Boutt, D. F.; Hackman, A. M.; Davenport, G.

    2013-12-01

    The species richness of wetland ecosystems' are sustained by the presence of discrete groundwater discharge, or springs. Springs provide thermal refugia and a source of fresh water inflow crucial for survival of many wetland species. The subsurface drivers that control the spatial distribution of surficial springs throughout peatland complexes are poorly understood due to the many challenges peatlands pose for hydrologic characterization, such as the internal heterogeneities, soft, dynamic substrate, and low gradient of peat drainage. This has previously made it difficult to collect spatial data required for restoration projects that seek to support spring obligate and thermally stressed species such as trout. Tidmarsh Farms is a 577-acre site in Southeastern Massachusetts where 100+ years of cranberry farming has significantly altered the original peatland hydrodynamics and ecology. Farming practices such as the regular application of sand, straightening of the main channel, and addition of drainage ditches has strongly degraded this peatland ecosystem. Our research has overlain non-invasive geophysical, thermal, and water isotopic data from the Tidmarsh Farms peatland to provide a detailed visualization of how subsurface peat structure and spring patterns correlate. Ground penetrating radar (GPR) has proven particularly useful in characterizing internal peat structure and the mineral soil interface beneath peatlands, we interpolate the peatland basin at a large scale (1 km2) and compare this 3-D surface to the locations of springs on the peat platform. Springs, expressed as cold anomalies in summer and warm anomalies in winter, were specifically located by combining fiber-optic and infrared thermal surveys, utilizing the numerous relic agricultural drainage ditches as a sampling advantage. Isotopic signatures of the spring locations are used to distinguish local and regional discharge, differences that can be explained in part by the peat basin structure

  1. Spring-Tab Lock Washer

    NASA Technical Reports Server (NTRS)

    Finckenor, Jeff; Rogers, Dylan; Rodriguez, Pete

    1993-01-01

    Improved spring-tab lock washer offers alternative to such positive-locking devices as cotter pins and lock wires and to conventional split-ring lock washers. Does not dig into fastened parts with sharp edges; less likely to inflict scratches causing cracks. Contains three winglike spring tabs and three alignment pips, pressed into mating dimples in surface of part to be fastened. Spring tabs on lock washer allow only clockwise rotation (tightening) of bolt or nut.

  2. How does the anthropogenic activity affect the spring discharge?

    NASA Astrophysics Data System (ADS)

    Hao, Yonghong; Zhang, Juan; Wang, Jiaojiao; Li, Ruifang; Hao, Pengmei; Zhan, Hongbin

    2016-09-01

    Karst hydrological process has largely been altered by climate change and human activity. In many places throughout the world, human activity (e.g. groundwater pumping and dewatering from mining) has intensified and surpassed climate change, where human activity becomes the primary factor that affects groundwater system. But it is still largely unclear how the human activity affects spring discharge in magnitude and periodicity. This study investigates the effects of anthropogenic activity on spring discharge, using the Xin'an Springs of China as an example. The Xin'an Spring discharge were divided into two time periods: the pre-development period from 1956 to 1971 and the post-development period from 1972 to 2013. We confirm the dividing time (i.e. 1971) of these two periods using the Wilcoxon rank-sum test. Then the wavelet transform and wavelet coherence were used to analyze the karst hydrological processes for the two periods respectively. We analyze the correlations of precipitation and the Xin'an spring discharge with the monsoons including the Indian Summer Monsoon (ISM) and the West North Pacific Monsoon (WNPM) and the climate teleconnections including El Niño Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO), respectively. The results indicated that the spring discharge was attenuated about 19.63% under the influence of human activity in the Xin'an Springs basin. However, human activity did not alter the size of the resonance frequencies between the spring discharge and the monsoons. In contrast, it reinforced the periodicities of the monsoons-driven spring discharge. It suggested that human has adapted to the major climate periodicities, and human activity had the same rhyme with the primary climate periodicity. In return, human activity enhances the correlation between the monsoons and the spring discharge.

  3. Springing into Spring: Reading Games for the Season

    ERIC Educational Resources Information Center

    Maxwell, D. Jackson

    2008-01-01

    As spring arrives, more time is spent outdoors. Unfortunately, as spring fever hits, books and learning often take a backseat. The goal is for educators to find a way to re-engage learners. In this article, the author presents a seasonal story and game that can help catch students' attention by making learning both informative and entertaining.…

  4. BLACKJACK SPRINGS WILDERNESS, WISCONSIN.

    USGS Publications Warehouse

    Schulz, Klaus J.

    1984-01-01

    The mineral-resource potential of the Blackjack Springs Wilderness in northern Wisconsin was evaluated. The lack of bedrock exposures in or near the wilderness and the thick mantle of glacial sediments precludes a detailed assessment of the mineral potential of the wilderness. However, based on presently available data, the area is concluded to offer little promise for the occurrence of mineral resources. If mineral deposits exist in the area, they would be under thick glacial cover and probably be of the massive sulfide type in association with metavolcanic rocks or be magmatic copper-nickel in association with metamorphosed mafic intrusive rocks. Sand and gravel resources occur in the wilderness, but they are abundant regionally, outside the wilderness. No other metallic or energy resources were identified in this study.

  5. Spring loaded thermocouple module

    DOEpatents

    McKelvey, Thomas E.; Guarnieri, Joseph J.

    1985-01-01

    A thermocouple arrangement is provided for mounting in a blind hole of a specimen. The thermocouple arrangement includes a cup-like holder member, which receives an elongated thermal insulator, one end of which is seated at an end wall of the holder. A pair of thermocouple wires, threaded through passageways in the insulator, extend beyond the insulator member, terminating in free ends which are joined together in a spherical weld bead. A spring, held captive within the holder, applies a bias force to the weld bead, through the insulator member. The outside surface of the holder is threaded for engagement with the blind hole of the specimen. When the thermocouple is installed in the specimen, the spherical contact surface of the weld bead is held in contact with the end wall of the blind hole, with a predetermined bias force.

  6. Spring loaded thermocouple module

    DOEpatents

    McKelvey, T.E.; Guarnieri, J.J.

    1984-03-13

    A thermocouple arrangement is provided for mounting in a blind hole of a specimen. The thermocouple arrangement includes a cup-like holder member, which receives an elongated thermal insulator, one end of which is seated at an end wall of the holder. A pair of thermocouple wires, threaded through passageways in the insulator, extend beyond the insulator member, terminating in free ends which are joined together in a spherical weld bead. A spring, held captive within the holder, applies a bias force to the weld bead, through the insulator member. The outside surface of the holder is threaded for engagement with the blind hole of the specimen. When the thermocouple is installed in the specimen, the spherical contact surface of the weld bead is held in contact with the end wall of the blind hole, with a predetermined bias force.

  7. Large-scale climate control on the occurrence of turbid events on interannual scales in a karstified, heavily exploited karst system in northwestern France

    NASA Astrophysics Data System (ADS)

    Massei, N.; Laignel, B.; Dupont, J. P.

    2015-12-01

    High-amplitude turbid episodes at water supplies can cause significant sanitary issues to populations. Owing to their hydrogeologic specificity, karst ground waters are particularly sensitive to such phenomena, involving either fast infiltration of turbid surface water or resuspension of intra-karstic sediments during flood events. In some regions, such as Upper Normandy (France), soil erosion and karst features in the chalk aquifer are at the origin of major turbid events which may result in interrupted water supply to the local populations. Thanks to a long daily turbidity time series corresponding to measurements at one major karst spring since the mid-80's, we could investigate the large-scale atmospheric circulation control on below- or above-average turbidity periods. The turbidity time-series actually display periods on pluriannual duration during which daily turbid events are more frequent and have higher amplitudes, which can not be seen on daily precipitation records. Comparison was made between annual precipitation amounts, chalk aquifer water table variations and turbidity throughout this approximately 25-year period, which showed interannual recharge periods associated to above-normal turbid conditions. We then studied the linkages between such variations and large-scale atmospheric circulation using a NOAA sea level pressure reanalysis product. A wavelet multiresolution analysis of all hydrological and climatic signals revealed common aperiodic oscillations on interannual scales and allowed identification of the large-scale, interannual-scale atmospheric pattern that was responsible for those above-normal turbid periods; this atmospheric pattern was not necessarily similar to that responsible to any individual short-term turbid event.

  8. Spring loaded locator pin assembly

    DOEpatents

    Groll, T.A.; White, J.P.

    1998-03-03

    This invention deals with spring loaded locator pins. Locator pins are sometimes referred to as captured pins. This is a mechanism which locks two items together with the pin that is spring loaded so that it drops into a locator hole on the work piece. 5 figs.

  9. Spring loaded locator pin assembly

    DOEpatents

    Groll, Todd A.; White, James P.

    1998-01-01

    This invention deals with spring loaded locator pins. Locator pins are sometimes referred to as captured pins. This is a mechanism which locks two items together with the pin that is spring loaded so that it drops into a locator hole on the work piece.

  10. Experimenting with Inexpensive Plastic Springs

    ERIC Educational Resources Information Center

    Perez, Leander; Marques, Adriana; Sánchez, Iván

    2014-01-01

    Acommon undergraduate laboratory experience is the determination of the elastic constant of a spring, whether studying the elongation under a static load or studying the damped harmonic motion of the spring with a suspended mass. An alternative approach to this laboratory experience has been suggested by Menezes et al., aimed at studying the…

  11. Single-Crystal Springs For Accelerometers

    NASA Technical Reports Server (NTRS)

    Vanzandt, Thomas R.; Kaiser, William J.; Kenny, Thomas W.

    1995-01-01

    Thermal noise reduced, enabling use of smaller proof masses. Spring-and-mass accelerometers in which springs made of single-crystal material being developed. In spring-and-mass accelerometer, proof mass attached to one end of spring, and acceleration of object at other end of spring measured in terms of deflection of spring, provided frequency spectrum of acceleration lies well below resonant frequency of spring-and-proof-mass system. Use of single-crystal spring materials instead of such polycrystalline spring materials as ordinary metals makes possible to construct highly sensitive accelerometers (including seismometers) with small proof masses.

  12. Mallow Springs, County Cork, Ireland

    NASA Astrophysics Data System (ADS)

    Aldwell, C. R.

    1996-03-01

    Because of its copious and reliable rainfall, Ireland has an abundance of springs. Many of the larger ones issue from the Carboniferous limestone that occurs in over 40% of the country. The spring water is mainly a calcium bicarbonate type with a temperature of about 10°C. In the 18th century, warm and cold springs were developed as spas in various parts of Ireland. The popularity of these springs was short and most were in major decline by 1850. Today only one cold spa at Lisdoonvarna, Co. Clare is still operating. Springs in Ireland were places of religious significance for the pre-Christian Druidic religion. In the Christian period they became holy wells, under the patronage of various saints. Cures for many different ailments were attributed to water from these wells.

  13. 49 CFR 229.65 - Spring rigging.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Spring rigging. 229.65 Section 229.65....65 Spring rigging. (a) Protective construction or safety hangers shall be provided to prevent spring planks, spring seats or bolsters from dropping to track structure in event of a hanger or spring...

  14. 49 CFR 229.65 - Spring rigging.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Spring rigging. 229.65 Section 229.65....65 Spring rigging. (a) Protective construction or safety hangers shall be provided to prevent spring planks, spring seats or bolsters from dropping to track structure in event of a hanger or spring...

  15. 49 CFR 229.65 - Spring rigging.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Spring rigging. 229.65 Section 229.65....65 Spring rigging. (a) Protective construction or safety hangers shall be provided to prevent spring planks, spring seats or bolsters from dropping to track structure in event of a hanger or spring...

  16. 49 CFR 229.65 - Spring rigging.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Spring rigging. 229.65 Section 229.65....65 Spring rigging. (a) Protective construction or safety hangers shall be provided to prevent spring planks, spring seats or bolsters from dropping to track structure in event of a hanger or spring...

  17. Linear magnetic spring and spring/motor combination

    NASA Technical Reports Server (NTRS)

    Patt, Paul J. (Inventor); Stolfi, Fred R. (Inventor)

    1991-01-01

    A magnetic spring, or a spring and motor combination, providing a linear spring force characteristic in each direction from a neutral position, in which the spring action may occur for any desired coordinate of a typical orthogonal coordinate system. A set of magnets are disposed, preferably symmetrically about a coordinate axis, poled orthogonally to the desired force direction. A second set of magnets, respectively poled opposite the first set, are arranged on the sprung article. The magnets of one of the sets are spaced a greater distance apart than those of the other, such that an end magnet from each set forms a pair having preferably planar faces parallel to the direction of spring force, the faces being offset so that in a neutral position the outer edge of the closer spaced magnet set is aligned with the inner edge of the greater spaced magnet set. For use as a motor, a coil can be arranged with conductors orthogonal to both the magnet pole directions and the direction of desired spring force, located across from the magnets of one set and fixed with respect to the magnets of the other set. In a cylindrical coordinate system having axial spring force, the magnets are radially poled and motor coils are concentric with the cylinder axis.

  18. Spring Dust Storm Smothers Beijing

    NASA Technical Reports Server (NTRS)

    2002-01-01

    A few days earlier than usual, a large, dense plume of dust blew southward and eastward from the desert plains of Mongolia-quite smothering to the residents of Beijing. Citizens of northeastern China call this annual event the 'shachenbao,' or 'dust cloud tempest.' However, the tempest normally occurs during the spring time. The dust storm hit Beijing on Friday night, March 15, and began coating everything with a fine, pale brown layer of grit. The region is quite dry; a problem some believe has been exacerbated by decades of deforestation. According to Chinese government estimates, roughly 1 million tons of desert dust and sand blow into Beijing each year. This true-color image was made using two adjacent swaths (click to see the full image) of data from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS), flying aboard the OrbView-2 satellite, on March 17, 2002. The massive dust storm (brownish pixels) can easily be distinguished from clouds (bright white pixels) as it blows across northern Japan and eastward toward the open Pacific Ocean. The black regions are gaps between SeaWiFS' viewing swaths and represent areas where no data were collected. Image courtesy the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  19. Piston and spring powered engine

    SciTech Connect

    Samodovitz, A. J.

    1985-12-10

    The invention is an improved piston engine, either two stroke or four stroke. In one, two stroke, one cylinder embodiment, the improvement comprises two springs connecting between the piston and the base of the piston. These springs are relatively relaxed when the crank is at top dead center. Then during the power/intake stroke, some of the fuel's energy is delivered to the crankshaft and some is used to compress the springs. The stored energy in the springs is delivered to the crankshaft during the exhaust/compression stroke while the springs return to their relatively relaxed condition. As a result, energy is delivered to the crankshaft during both strokes of the cycle, and the engine runs smooth. In one, four stroke, two cylinder embodiment, each cylinder has springs as described above, the cranks of each cylinder are aligned, and the cam sets one cylinder in the power stroke while the other is in the intake stroke. As a result, the engine runs smooth because energy is delivered to the crankshaft during all four strokes of the cycle, during two of the strokes by the burning fuel and during the other two by the release of energy in the springs. In both embodiments, a heavy crankshaft is not needed because of the more uniform power delivery.

  20. Siliceous Shrubs in Yellowstone's Hot Springs: Implications for Exobiological Investigations

    NASA Technical Reports Server (NTRS)

    Guidry, S. A.; Chafetz, H. S.

    2003-01-01

    Potential relict hot springs have been identified on Mars and, using the Earth as an analog, Martian hot springs are postulated to be an optimal locality for recognizing preserved evidence of extraterrestrial life. Distinctive organic and inorganic biomarkers are necessary to recognize preserved evidence of life in terrestrial and extraterrestrial hot spring accumulations. Hot springs in Yellowstone National Park, Wyoming, U.S.A., contain a wealth of information about primitive microbial life and associated biosignatures that may be useful for future exobiological investigations. Numerous siliceous hot springs in Yellowstone contain abundant, centimeter-scale, spinose precipitates of opaline silica (opal-A). Although areally extensive in siliceous hot spring discharge channel facies, these spinose forms have largely escaped attention. These precipitates referred to as shrubs, consist of porous aggregates of spinose opaline silica that superficially resemble miniature woody plants, i.e., the term shrubs. Shrubs in carbonate precipitating systems have received considerable attention, and represent naturally occurring biotically induced precipitates. As such, shrubs have great potential as hot spring environmental indicators and, more importantly, proxies for pre-existing microbial life.

  1. Biogeographic patterns of desert springs in the Great Basin with an emphasis on regional aquifer thermal springs as refugia for vulnerable crenobiotic species

    NASA Astrophysics Data System (ADS)

    Forrest, M.; Sada, D. W.; Norris, R. D.

    2013-12-01

    The desert springs of the Great Basin Region in western North America provide ideal systems to study biogeographic and evolutionary patterns. In arid regions, springs are biodiversity hotspots because they often provide the sole source of water for the biota within and around them. In the Great Basin, springs provide critical habitat for diverse and extensive crenobiotic flora and fauna comprising over 125 endemic species. These aquatic environments represent island ecosystems surrounded by seas of desert, and researchers have compiled large databases of their biota and chemistry. Consequently, desert springs are excellent systems for biogeographic studies and multivariate statistical analyses of relationships between the chemical and physical characteristics of the springs and the biological communities that they support. The purpose of this study is to elucidate the relationships between the physicochemical characteristics of springs and their biota using multivariate statistical analyses to characterize 1325 springs, including regional aquifer springs, local aquifer cold springs and geothermal springs. The analyses reveal that regional aquifer thermal springs harbor disproportionate numbers of crenobiotic species including endemic gastropods, fishes, and aquatic insects. However, these regional aquifer springs also contain significantly more introduced species than cold and geothermal local aquifer springs. Springs are threatened by anthropogenic impacts including groundwater depletion and pollution, alteration of flow regimes, and the introduction of exotic species. In this study, one of the major factors that distinguished regional aquifer thermal springs from cold and geothermal local aquifer springs was the higher number of introduced species found in regional aquifer springs. This may be due to the influences of the same physicochemical characteristics that allow regional aquifer springs to serve as refugia for endemic species--species that are able to gain

  2. Hydrogeology of the mineral springs at Manitou Springs, Colorado

    SciTech Connect

    Maslyn, R.M.; Blomquist, P.K.

    1985-01-01

    Manitou Springs, a small resort community located at the base of 14,110 foot Pikes Peak, is situated at the south end of the southward plunging Williams Canyon Anticline. This is truncated south of town by the Ute Pass Reverse Fault, with over 30,000 feet of displacement. Paleozoic limestones are exposed north of Manitou Springs in north-south trending Williams Canyon. The Mississippian age Leadville Limestone and underlying Ordovician age Manitou Limestone contain over 40 caves, including the 8500-foot long Cave of the Winds system. These limestones continue under Manitou Springs, where cave forming processes have resulted in water-filled caverns. The 28 natural springs and flowing wells in Manitou Springs source in the limestone caverns. This carbonate aquifer is bounded by the Ute Pass Fault on the west and southwest, the Rampart Range Fault to the east, and open to recharge from exposed limestone to the north. Areal extent of the aquifer is approximately 3.5 spare miles, containing an estimated 10 billion gallons. In the past 100 years, spring development has lowered the potentiometric surface 50 feet. Contemporary and historical chemical analyses of the mineral water show high concentrations of calcium, magnesium, bicarbonate, and carbon dioxide gas. This suggests prolonged exposure of the water to limestone, as confirmed by Carbon 14 age-dating values of up to 30,000 years.

  3. Spatiotemporal patterns of stable isotopes and hydrochemistry in springs and river flow of the upper Karkheh River Basin, Iran.

    PubMed

    Osati, Khaled; Koeniger, Paul; Salajegheh, Ali; Mahdavi, Mohammad; Chapi, Kamran; Malekian, Arash

    2014-06-01

    Karst springs of the Zagros Mountains contribute a significant amount to agricultural and human water demands of western and south-western Iran. For an adequate management of available water resources in semi-arid and arid regions, sufficient hydrological monitoring is needed, and hydro-chemical and isotope hydrological data provide important additional information. About 350 water samples were collected from precipitation, river water, and karst springs of the upper part of the Karkheh River Basin (20,895 km(2)) located between 33°35(') and 34°55(') North and 46°22(') and 49°10(') East with elevations ranging from 928 to 3563 m above sea level. Sampling was conducted in monthly time resolution from August 2011 to July 2012. All samples were analysed for hydro-chemical parameters (pH, electrical conductivity, and major ions) and stable isotopes (deuterium, oxygen-18). Isotope values of precipitation indicate a local meteoric water line (Zagros MWL δ(2)H=6.8 δ(18)O+10.1; R(2)=0.99) situated between the Mediterranean MWL and Global MWL. Spring and river water isotope values vary between-7.1 and-4.1 ‰, and-38 and-25 ‰ for δ(18)O and δ(2)H, respectively, responding to winter snowmelt and evaporation. This work implements stable isotopes and hydro-chemical information of springs and river water to understand hydrological and hydro-geological interrelations in karstic semi-arid areas and helps to improve the current water resources management practices of western Iran. PMID:24437989

  4. The morphology and hydrology of small spring-dominated channels

    NASA Astrophysics Data System (ADS)

    Griffiths, Ronald E.; Anderson, Diana E.; Springer, Abraham E.

    2008-12-01

    Small, low order channels located in wet meadows along the Mogollon Rim of northern Arizona that receive the bulk of their flow from spring discharge exhibit a morphology that differs markedly from channels that receive the bulk of their flow from runoff. These small, spring-dominated channels generally have dense vegetation cover, vertical (or near vertical) banks with flat channel beds that are armored with clasts up to 60 mm. Clasts armoring the spring-dominated channels become mobile at 45 to 85% of the bankfull depth. The lack of fine-grained material in the bed of the spring-dominated channels reflects the small drainage size, lack of fine grain input from the spring, and winnowing affect of the consistent discharge. Minor amounts of large woody debris were present in some of the spring-dominated channels, however, unlike previous studies it does not appear to play a role in the spring-dominated channel morphology. Sinuosity values for spring-dominated channels averaged 1.19, while the average sinuosity values for the runoff-dominated channels, 1.08, were significantly lower. Measured width-to-depth ratios averaged 2.4 in the spring-dominated channels, much lower than the average ratio of 11.6 found for the runoff-dominated channels. The standard deviation of width-to-depth ratios was higher for runoff-dominated channels, reflecting a more variable channel profile. A third channel type, here referred to as hybrid channels, receive significant flow from both springs and runoff. These channels have characteristics that fall between spring-dominated and runoff-dominated channels. Elevation, gradient, organic matter content, and sediment grain size distribution of the wet meadows in which the channels are formed do not exhibit significant differences between channel types, suggesting that these factors are not responsible for the observed differences in channel morphologies. The major differences in controls on the channel morphology found between the spring

  5. Geothermal resource assessment of Idaho Springs, Colorado. Resource series 16

    NASA Astrophysics Data System (ADS)

    Repplier, F. N.; Zacharakis, T. G.; Ringrose, C. D.

    Geothermal springs and wells were assessed for hydrothermal conditions. The temperature of these waters ranges from a low of 680 F to a high of 1270 F. The hydrothermal conditions of the Idaho Springs region in 1980 were defined by electrical geophysical, soil mercury geochemical, and reconnaissance geological and hydrogeological surveys. The investigation was limited to the immediate area surrounding the thermal springs at the Indian Springs Resort. It is found that bedrock of the region is faulted and fractured metamorphosed Precambrian gneisses and schists, locally intruded by Tertiary age plutons and dikes. It is shown that the thermal waters most likely are fault controlled and the thermal area does not have a large areal extent.

  6. Spring Small Grains Area Estimation

    NASA Technical Reports Server (NTRS)

    Palmer, W. F.; Mohler, R. J.

    1986-01-01

    SSG3 automatically estimates acreage of spring small grains from Landsat data. Report describes development and testing of a computerized technique for using Landsat multispectral scanner (MSS) data to estimate acreage of spring small grains (wheat, barley, and oats). Application of technique to analysis of four years of data from United States and Canada yielded estimates of accuracy comparable to those obtained through procedures that rely on trained analysis.

  7. Spring bloom onset in the Nordic Seas

    NASA Astrophysics Data System (ADS)

    Mignot, Alexandre; Ferrari, Raffaele; Mork, Kjell Arne

    2016-06-01

    The North Atlantic spring bloom is a massive annual growth event of marine phytoplankton, tiny free-floating algae that form the base of the ocean's food web and generates a large fraction of the global primary production of organic matter. The conditions that trigger the onset of the spring bloom in the Nordic Seas, at the northern edge of the North Atlantic, are studied using in situ data from six bio-optical floats released north of the Arctic Circle. It is often assumed that spring blooms start as soon as phytoplankton cells daily irradiance is sufficiently abundant that division rates exceed losses. The bio-optical float data instead suggest the tantalizing hypothesis that Nordic Seas blooms start when the photoperiod, the number of daily light hours experienced by phytoplankton, exceeds a critical value, independently of division rates. The photoperiod trigger may have developed at high latitudes where photosynthesis is impossible during polar nights and phytoplankton enters into a dormant stage in winter. While the first accumulation of biomass recorded by the bio-optical floats is consistent with the photoperiod hypothesis, it is possible that some biomass accumulation started before the critical photoperiod but at levels too low to be detected by the fluorometers. More precise observations are needed to test the photoperiod hypothesis.

  8. Connections between winter snowpack and subsequent spring floods in Norway

    NASA Astrophysics Data System (ADS)

    Schlichting, Lena; Engeland, Kolbjørn; Holmqvist, Erik; Bache Stranden, Heidi

    2016-04-01

    In Norway many inland and mountainous catchments have a hydrological regime where snow accumulates during winter. The runoff is delayed until the snow melts during spring. These processes are important for flood forecasting and water resource management, such as operation of hydropower reservoirs. It is commonly assumed that spring flood volume and peak linked to antecedent conditions such as winter snowpack, i.e. a large winter snowpack results in a high spring flood. The aims of this study are (i) to identify for which catchments a high correlation between snow water equivalent (SWE) at the end of the snow accumulation season and the subsequent spring flood, and (ii) establish regression models for these catchments to be used for seasonal flood forecasting. Daily runoff data from 43 distributed catchments all over Norway, each with at least 50 years of observations and a flood regime which is significantly influenced by snowmelt, were used. For each of these catchments we extracted SWE, precipitation and temperature on daily resolution from the on gridded data of Senorge.no. A peak-over-threshold approach was used to select independent flood events above the 90-th percentile. Maximum discharge, duration and volume were calculated for each event. The contribution of rain and snowmelt to each flood was additionally determined, based on snowmelt, precipitation and temperature data. The spring flood was defined as the first flood event that occurs after the date of maximum SWE, and the snowmelt contribution of at least 70%. The contribution of rain to a spring flood is independent of maximum SWE, resulting in a weaker correlation between maximum SWE and spring flood size. We therefore scaled the flood with the percentage of snow contribution to the flood event in order to adjust for the contribution from rain. The correlations between SWE and the spring flood were higher for scaled spring floods than for the unscaled ones. The results show for half of the stations a

  9. 49 CFR 236.822 - Switch, spring.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Switch, spring. 236.822 Section 236.822... Switch, spring. A switch equipped with a spring device which forces the points to their original position after being trailed through and holds them under spring compression....

  10. 14 CFR 23.687 - Spring devices.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Spring devices. 23.687 Section 23.687... Systems § 23.687 Spring devices. The reliability of any spring device used in the control system must be established by tests simulating service conditions unless failure of the spring will not cause flutter...