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Speleology in Kazakhstan

Shakalov on 04 Jul, 2018
Hello everyone!   I pleased to invite you to the official site of Central Asian Karstic-Speleological commission ("Kaspeko")   There, we regularly publish reports about our expeditions, articles and reports on speleotopics, lecture course for instructors, photos etc. ...

New publications on hypogene speleogenesis

Klimchouk on 26 Mar, 2012
Dear Colleagues, This is to draw your attention to several recent publications added to KarstBase, relevant to hypogenic karst/speleogenesis: Corrosion of limestone tablets in sulfidic ground-water: measurements and speleogenetic implications Galdenzi,

The deepest terrestrial animal

Klimchouk on 23 Feb, 2012
A recent publication of Spanish researchers describes the biology of Krubera Cave, including the deepest terrestrial animal ever found: Jordana, Rafael; Baquero, Enrique; Reboleira, Sofía and Sendra, Alberto. ...

Caves - landscapes without light

akop on 05 Feb, 2012
Exhibition dedicated to caves is taking place in the Vienna Natural History Museum   The exhibition at the Natural History Museum presents the surprising variety of caves and cave formations such as stalactites and various crystals. ...

Did you know?

That moisture tension is the equivalent negative pressure of water in an unsaturated porous medium equal to the pressure that must be applied to the medium to bring the water to hydraulic equilibrium through a porous permeable material with a pool of water of the same composition. synonym: capillary tension [22].?

Checkout all 2699 terms in the KarstBase Glossary of Karst and Cave Terms

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Featured articles from Cave & Karst Science Journals
Chemistry and Karst, White, William B.
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Featured articles from other Geoscience Journals
Karst environment, Culver D.C.
Mushroom Speleothems: Stromatolites That Formed in the Absence of Phototrophs, Bontognali, Tomaso R.R.; D’Angeli Ilenia M.; Tisato, Nicola; Vasconcelos, Crisogono; Bernasconi, Stefano M.; Gonzales, Esteban R. G.; De Waele, Jo
Calculating flux to predict future cave radon concentrations, Rowberry, Matt; Marti, Xavi; Frontera, Carlos; Van De Wiel, Marco; Briestensky, Milos
Microbial mediation of complex subterranean mineral structures, Tirato, Nicola; Torriano, Stefano F.F;, Monteux, Sylvain; Sauro, Francesco; De Waele, Jo; Lavagna, Maria Luisa; D’Angeli, Ilenia Maria; Chailloux, Daniel; Renda, Michel; Eglinton, Timothy I.; Bontognali, Tomaso Renzo Rezio
Evidence of a plate-wide tectonic pressure pulse provided by extensometric monitoring in the Balkan Mountains (Bulgaria), Briestensky, Milos; Rowberry, Matt; Stemberk, Josef; Stefanov, Petar; Vozar, Jozef; Sebela, Stanka; Petro, Lubomir; Bella, Pavel; Gaal, Ludovit; Ormukov, Cholponbek;
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Your search for organic-carbon (Keyword) returned 23 results for the whole karstbase:
Showing 1 to 15 of 23
Quaternary Paleoclimatology of the Black Sea basin, 1979, Schrader Hans Joachim,
The occurrence of polyhaline, mesohaline and oligohaline diatom, silicoflagellate, ebridian and chrysomonad populations in late Quaternary Black Sea sediments (DSDP Leg 42B) forms the basis for reconstruction of surface water paleosalinities in the Black Sea basin over the last 3 million years. Four major periods with increased salinites are separated by extended freshwater periods. Based on paleosalinites, indicators of trophic freshwater conditions and changes in diatom species diversity, a correlation is made to the northern Europian glacial--interglacial stratigraphy and this correlation is used to place paleoenvironmental events into a chronostratigraphy. The `synchronous' late Quaternary occurrence of sediments rich in organic carbon in both the Eastern Mediterranean and the Black Sea supports this interpretation.Three different stages in the interaction between the Black Sea and the Eastern Mediterranean Sea are defined: Stage A (exchange of freshwater and marine water similar to the present day flux) during the Holocene, Eemian, Holsteinian and Pliocene; Stage B (freshwater conditions with only occasional marine spills) during the Saalian, the Waalian, the Tiglian and the Praetiglian; and Stage C (freshwater conditions with no inflow of marine waters) during the Weichselian, the Elsterian and Eburonian

Aufeis of the Firth River basin, Northern Yukon Canada: Insights into permafrost hydrogeology and Karst, 1997, Clark Id, Lauriol B,
The 31-km(2) aufeis ice sheet of the upper Firth River holds a wealth of information on groundwater hydrology in periglacial environments. Baseflow recession calculations, corrected for aufeis storage (12% of basin discharge), indicate specific groundwater recharge rates of up to 100 mm yr(-1) (up to 50% of runoff), suggesting a significant proportion of drainage from karst. The upper Firth River aufeis is a composite aufeis, with discrete baseflow contributions from different watersheds. Since the late Pleistocene, annual growth of the aufeis has exerted a strong control on lateral erosion and the local river channel geomorphology. Two groundwater recharge processes are distinguished on the basis of carbonate geochemistry and 8(13)C: (1) Methanogenic groundwaters, with C-13(DIC) up to -3.3 parts per thousand, are recharged through saturated soils underlain by permafrost; conditions which support anaerobic consumption of dissolved organic carbon (DOC) and produce up to 700 mu g-CH4 L-1 (calculated), and (2) Karst groundwaters, with C-13-depleted DIC, recharged through unsaturated soils and circulate through fissured talik in the carbonate bedrock. Most drainage from the region shows varying contributions of these two groundwaters, although a greater contribution from the methanogenic groundwaters occurs in north-facing watersheds. The 8(13)C values far cryogenic calcite precipitates in the ice indicate that the karst groundwaters are the major contribution to aufeis growth. The combined use of 8(13)C(DIC) and geochemistry may be a useful tool to quantify methanogenesis in northern watersheds

Interactions between ground water and surface water in the Suwannee River Basin, Florida, 1997, Katz B. G. , Dehan R. S. , Hirten J. J. , Catches J. S. ,
Ground water and surface water constitute a single dynamic system in most parts of the Suwannee River basin due to the presence of karst features that facilitate the interaction between the surface and subsurface. Low radon-222 concentrations (below background levels) and enriched amounts of oxygen-18 and deuterium in ground water indicate mixing with surface water in parts of the basin. Comparison of surface water and regional ground water flow patterns indicate that boundaries for ground water basins typically do not coincide with surface water drainage subbasins. There are several areas in the basin where around water flow that originates outside of the Suwannee River basin crosses surface water basin boundaries during both low-flow and high-flow conditions. In a study area adjacent to the Suwannee River that consists predominantly of agricultural land use, 18 wells tapping the Upper Floridan aquifer and 7 springs were sampled three times during 1990 through 1994 for major dissolved inorganic constituents, trace elements, and nutrients. During a period of above normal rainfall that resulted in high river stage and high ground water levels in 1991, the combination of increased amounts of dissolved organic carbon and decreased levels of dissolved oxygen in ground water created conditions favorable for the natural reduction of nitrate by denitrification reactions in the aquifer. As a result, less nitrate was discharged by ground water to the Suwannee River

Spheroidal dolomites in a Visean karst system - Bacterial induced origin?, 1997, Nielsen P. , Swennen R. , Dickson J. A. D. , Fallick A. E. , Keppens E. ,
Spheroidal dolomite crystals occur in the karstified top of a Dinantian dolomite sequence in eastern Belgium. The spheroidal dolomite crystals are best developed at the base of the karst system. The dolomite crystals are characterized by a spherulitic or dumb-bell inclusion pattern, and are overgrown by dolomite cements with a rhombohedral outline. They are considered to be bacterially related precipitates based on, (1) textural similarities with documented bacteriogenic precipitates, (2) the presence of 'bacterial' microspheres and framboidal pyrite embedded within the dolomite, and (3) their general geological setting. The geochemical characteristics of the dolomites and associated minerals support a bacterial origin. The ubiquity of framboidal pyrite, depleted in S-34 (delta(34)S = - 22.4 to - 25.5 parts per thousand CDT), testifies to a period of bacterial sulphate reduction. The isotopic composition of the spheroidal dolomites (delta(13)C = - 2.4 to - 3.2 parts per thousand PDB and delta(18)O = - 3.8 to - 3.4 parts per thousand PDB) suggest a contribution from oxidized organic carbon produced during bacterial sulphate reduction. Sulphate reduction may also result in a concomitant O-18 depletion if the system is nearly closed. It is however, evident from the sulphur isotopic composition of associated framboidal pyrite that the system was fairly open. The O-18 depletion of the spheroidal dolomite crystals (delta(18)O = - 3.8 to - 3.4 parts per thousand PDB) and their occurrence adjacent to, and within karst cavities suggests a mixing zone origin, with a significant proportion of freshwater in it. The rhombohedral cement-overgrowths have calculated delta(18)O values in the range of 0 to 5.3 parts per thousand PDB, which reflect precipitation from normal to slightly evaporated contemporaneous seawater

Kinetics and mechanisms of precipitation of calcite as affected by P-CO2 and organic ligands at 25 degrees C, 1998, Lebron I. , Suarez D. L. ,
This study was conducted to develop a model for the precipitation rate of calcite under varying CO2 partial pressures and concentrations of dissolved organic carbon (DOG). Precipitation rates of calcite were measured in solutions with supersaturation values (Omega) between 1 and 20 and in the presence of 2 m(2)L(-1) of calcite. Experiments were run at partial pressures of CO2 (P-CO2) in the range of 0.035-10 kPa and DOC concentrations in the range of 0.02-3.50 mM. The effects of these two variables were quantified separately for the precipitation mechanisms of crystal growth and heterogeneous nucleation. We found an increase in precipitation rate (at constant Omega) when P-CO2 increased. For constant Omega, we also found a linear relationship between calcite precipitation rate and activity of CaHCO3, indicating that CaHCO3 species have an active role in the mechanism of calcite precipitation. These findings suggest that the increase in the precipitation rate with higher P-CO2 levels is likely caused by the increase in the negative charge on the calcite surface together with an increase in the activity of CaHCO3 species in solution. The mechanism of inhibition of calcite crystal growth by organic ligands has been shown to be surface coating of the crystals by DOG. The amount of DOC adsorbed on the surface of the calcite crystals follows a Langmuir isotherm for all the P-CO2 levels studied; however, the amount of DOC necessary to inhibit calcite precipitation increased. With increasing P-CO2, the negative charge on the crystal increases, which affects crystal growth, but also these increases in P-CO2 cause a decrease in the solution pH and increase in the ionic strength for constant Omega. Solution pH and ionic strength affect the structure and degree of dissociation of the organic functional groups, which in turn affects the and DOC concentration on the inhibition of crystal growth and heterogeneous nucleation. The effect of P-CO2 and DOC concentration on the precipitation rate of calcite is expressed in a precipitation rate model which reflects the contributions of crystal growth and heterogeneous nucleation. Copyright (C) 1998 Elsevier Science Ltd

Oxidation of organic matter in a karstic hydrologic unit supplied through stream sinks (Loiret, France), 1998, Alberic P, Lepiller M,
The aim of this paper is to appraise the ability of the oxidation of riverine organic matter in the control of limestone dissolution, in a karst network. Biogeochemical processes during infiltration of river water into an alluvial aquifer have already been described for an average flow velocity of 4-5 m d(-1) (Jacobs, L. A., von Gunten, H. R., Keil, R, and Kuslys, M. (1988) Geochemical changes along a river-groundwater infiltration flow path: Glattfelden, Switzerland. Geochim. Cosmochim. Acta 52, 2693-2706; Von Gunten, H. R., Karametaxas, G., Krahenbuhl, U., Kuslys, M., Giovanoli R., Hoehn E. and Keil R. (1991) Seasonal biogeochemical cycles in riverborne groundwater. Geochim. Cosmochim. Acta 55, 3597-3609; Bourg, A. C. M. and Bertin, C. (1993) Quantitative appraisal of biogeochemical chemical processes during the infiltration of river water into an alluvial aquifer. Environ. Sci. Technol. 27, 661-666). Karstic drainage networks, such as in the River Loire-Val d'Orleans hydrologic system (Fig. 1), make possible flow velocities up to 200 m h(-1 a) and provide convenient access to different water samples several tens of km apart, at both extremities of the hydrologic unit (Chery, J.-L. (1983) Etude hydrochimique d'un aquifere karstique alimente par perte de cours d'eau (la Loire): Le systeme des calcaires de Beauce sous le val d'Orleans. These, Universite d'Orleans; Livrozet, E. (1984) Influence des apports de la Loire sur la qualite bacteriologique et chimique de l'aquifere karstique du val d'Orleans. These, Universite d'Orleans). Recharge of the karstic aquifer occurs principally from influent waters from stream sinks, either through coarse alluvial deposits or directly from outcrops of the regional limestone bedrock (Calcaires de Beauce). Recharge by seepage waters From the local catchment basin is small (Zunino, C., Bonnet, M. and Lelong, F. (1980) Le Val d'Orleans: un exemple d'aquifere a alimentation laterale. C. R. somm. Soc. Geol. Fr. 5, 195-199; Gonzalez R. (1992) Etude de l'organisation et evaluation des echanges entre la Loire moyenne et l'aquifere des calcaires de Beauce. These, Universite d'Orleans) and negligible in summer. This karstic hydrologic: system is the largest in France in terms of flow (tens to hundreds of m(3)/s) and provides the main water resource of the city of Orleans. Chemical compositions of influent waters (River Loire) and effluent waters (spring of the river Loiret) were compared, in particular during floods in summer 1992 and 1993 (Figs 2-4). Variation of chloride in the River Loire during the stream rise can be used as an environmental tracer of the underground flow (Fig. 2). Short transit times of about 3 days are detectable (Fig, 2) which are consistent with earlier estimations obtained with chemical tracers (Ref. in Chery, J.-L. (1983) These, Universite d'Orleans). Depending on the hydrological regime of the river, organic carbon discharge ranges between 3-7 and 2-13 mg/l for dissolved and particulate matter respectively (Fig. 3). Eutrophic characteristics and high algal biomasses are found in the River Loire during low water (Lair, N. and Sargos, D. (1993) A 10 year study at four sites of the middle course of the River Loire. I - Patterns of change in hydrological, physical and chemical variables in relation to algal biomass. Hudroecol. Appl. 5, 1-27) together with more organic carbon rich suspended particulate matter than during floods (30-40 C-org % dry weight versus 5-10%). Amounts of total organic carbon and dissolved oxygen (Fig. 3) dramatically decrease during the underground transport, whereas conversely, dissolved calcium, alkalinity and inorganic carbon increase (Fig. 4). Anoxia of outflows map start in April. Dissolution of calcium carbonates along the influent path outweighs closed system calcite equilibrium of inflow river waters (Table 3). The impact of organic matter oxidation on calcite dissolution may be traced by variations of alkalinity and total carbonates in water. Following, Jacobs, L. A., von Gunten, H. R., Keil, R. and Kuslys, M. (1988) Geochemical changes along a river-groundwater infiltration flow path: Glattfelden, Switzerland. Geochim. Cosmochim. Acta 52, 2693-2706), results are shown graphically (Fig. 5). Extent of reactions is controlled by the consumption of dissolved O-2 and nitrate for organic matter oxidation and by the release of Ca2 for calcite dissolution (Table 2). The karstic network is considered to behave like a biological reactor not exchanging with the atmosphere, with steady inhabitant microbial communities (Mariotti A., Landreau A, and Simon B. (1988) N-15 isotope biogeochemisrry and natural denitrification process in groundwater: Application to the chalk aquifer of northern France. Geochim. Cosmochim. Acta 52, 1869-1878; Gounot, A.-M. (1991) Ecologie microbienne des eaux ei des sediments souterrains. Hydrogeologie, 239-248). Thus, energy requirements only are considered, not carbon assimilation. Moreover, there is no necessity to invoke any delay for nitrification enhancement, as observed elsewhere, after waste water discharge into the river (Chesterikoff, A., Garban, B., Billen, G. and Poulin, M. (1992) Inorganic nitrogen dynamics in the River Seine downstream from Paris (France). Biogeochem. 17, 147-164). Main microbial processes are assumed to be aerobic respiration, nitrification and denitrification. Reactions with iron and manganese, real but not quantitatively important, were neglected. Sulphate reduction and methane formation, certainly not active, were not considered. Denitrification, which is suggested by low nitrate and ammonium concentrations and anoxia in the outflow, is known to be rapid enough to be achieved in a short time (Dupain, S. (1992) Denitrification biologique heterotrophe appliquee au traitement des eaux d'alimentation: Conditions de fonclionnement et mise au point d'un procede. These, Universite Claude Bernard, Lyon). Reaction are somewhat arbitrary but conform to general acceptance (Morel, M. M. and Hering, J. G. (1993) Principles and Applications of Aquatic Chemistry. Wiley, New York). Anaerobic ammonium oxidation (Mulder A., van de Graaf, A. A., Robertson, L: A. and Kuenen, J. G. (1995) Anaerobic ammonium oxidation discovered in a denitrifying fluidized bed reactor. FEMS Microbiol. Ecol. 16, 177-184). although possible, was not considered. In fact, C/N ratio of the reactive organic matter has only mild repercussions on the results; i.e. in the same range as the analytical errors for alkalinity and total carbonates. The objective was simply to roughly confront characteristics of outflowing waters and the calculation. Respective roles of aerobes and denitrifiers, for instance, are not certain. Several periods during low water or floods were selected with various ranges for calcium dissolution or nitrate and oxygen concentrations. The result is that in most cases simulation and data are in reasonable accordance (Fig. 5). Amounts of organic matter in River Loire are generally sufficient to sustain the process (Table 3. Particulate organic matter is probably the most reactive. The balance of oxidation of organic matter indicates that about 65 mu g C-org/l.h are oxidized during the transport without much variation with the river regime or organic discharge. It is concluded that limestone dissolution is directly dependent on organic matter oxidation, but variation occurs (7-29 mg CuCO3/l) with the level of bases that can be neutralized in the River Loire water. (C) 1998 Elsevier Science Ltd. All rights reserved

Hydrochemical evidence for mixing of river water and groundwater during high-flow conditions, lower Suwannee River basin, Florida, USA, 1999, Crandall Ca, Katz Bg, Hirten Jj,
Karstic aquifers are highly susceptible to rapid infiltration of river water, particularly during periods of high flow. Following a period of sustained rainfall in the Suwannee River basin, Florida, USA, the stage of the Suwannee River rose from 3.0 to 5.88 m above mean sea level in April 1996 and discharge peaked at 360 m(3)/s. During these high-now conditions, water from the Suwannee River migrated directly into the karstic Upper Floridan aquifer, the main source of water supply for the area. Changes in the chemical composition of groundwater were quantified using naturally occurring geochemical tracers and mass-balance modeling techniques. Mixing of river water with groundwater was indicated by a decrease in the concentrations of calcium, silica, and Rn-222; and by an increase in dissolved organic carbon (DOC), tannic acid, and chloride, compared to low-flow conditions in water from a nearby monitoring well, Wingate Sink, and Little River Springs. The proportion (fraction) of river water in groundwater ranged from 0.13 to 0.65 at Wingate Sink and from 0.5 to 0.99 at well W-17258, based on binary mixing models using various tracers. The effectiveness of a natural tracer in quantifying mixing of river water and groundwater was related to differences in tracer concentration of the two end members and how conservatively the tracer reacted in the mixed water. Solutes with similar concentrations in the two end-member waters (Na, Mg, K, Cl, SO4, SiO2) were not as effective tracers for quantifying mixing of river water and groundwater as those with larger differences in end-member concentrations (Ca, tannic acid, DOC, Rn-222, HCO3)

Determination of the sources of nitrate contamination in karst springs using isotopic and chemical indicators, 2001, Panno S. V. , Hackley K. C. , Hwang H. H. , Kelly W. R. ,
The sources of nitrate (NO3-) in groundwater of the shallow karst aquifer in southwestern Illinois' sinkhole plain were investigated using chemical and isotopic techniques. The groundwater in this aquifer is an important source of potable water for about half of the residents of the sinkhole plain area. Previous work has shown that groundwater from approximately 18% of the wells in the sinkhole plain has NO3- concentrations in excess of the USEPA's drinking water standard of 10 mg N/1 Relative to background levels, the NO3- concentrations in water from 52% of the wells, and probably all of the springs in the study area, are anomalously high, suggesting that sources other than naturally occurring soil organic matter have contributed additional NO3- to groundwater in the shallow karst aquifer. This information, and the dominance of agriculture in the study area, suggest that agrichemical contributions may be significant. To test this hypothesis, water samples from 10 relatively large karst springs were collected during four different seasons and analyzed for inorganic constituents, dissolved organic carbon, atrazine, and delta (15) N and delta O-18 of the NO3- ions. The isotopic data were most definitive and suggested that the sources of NO3- in spring water are dominated by N-fertilizer with some possible influence of atmospheric NO3- and, to a much lesser extent, human and/or animal waste. Differences in the isotopic composition of NO3- and some of the chemical characteristics were observed during the four consecutive seasons in which spring water samples were collected. Isotopic values for delta N-15 and delta O-18 of the NO3- ranged from 3.2%o to 19.1%o and from 7.2%o to 18.7%o respectively. The trend of delta N-15 and delta O-18 data for NO3- also indicated that a significant degree of denitrification is occurring in the shallow karst hydrologic system (within the soil zone, the epikarst and the shallow karst aquifer) prior to discharging to springs. (C) 2001 Elsevier Science B.V. All rights reserved

Variation of delta C-13 in karst soil in Yaji Karst Experiment Site, Guilin, 2002, Pan G. X. , He S. Y. , Cao J. H. , Tao Y. X. , Sun Y. H. ,
This study deals with delta(13)C variation in karst soil system of Yaji Karst Experiment Site, Guilin, a typical region of humid subtropical karst formations. Samples of near ground air, plant tissue, soil and water (soil solution and karst spring) were respectively collected on site in different seasons during 1996-1999. Considerable variation of delta(13)C values are not only found with different carbon pools of soil organic carbon, soil air CO2 and soil water HCO3-, but also with the soil depths and with different seasons during a year. The delta(13)C values Of CO2 both of near ground air and soil air are lower in July than those in April by 1parts per thousand-4parts per thousand PDB. Our results indicate that the delta(13)C values of carbon in the water and air are essentially dependent on interface carbon interaction of air-plant-soil-rock-water governed by soil organic carbon and soil CO2 in the system

Effects of precipitation events on colloids in a karst aquifer, 2002, Shevenell L. , Mccarthy J. F. ,
The effects of precipitation events on colloid mobilization were evaluated during several storms from six wells in a karstic aquifer at the Oak Ridge Y-12 Plant in eastern Tennessee (USA). Turbidity increases and rapidly recedes following rain events. Although the magnitude of the turbidity increases are relatively small (less than or equal to4.78 NTU), the increased turbidity suggests transient increases in colloid abundance during storm versus non-storm periods. During the larger storms (> 19 mm), the increased turbidity is associated with increases in pH, total organic carbon (TOC) and temperature, and with decreases in dissolved oxygen (DO). These larger storms result in flushing of a greater proportion of higher pH, TOC (and lower DO) soil or matrix waters into the fractures and conduits than occurs during smaller storms. Smaller storms also result in increases in turbidity, but show increases in DO and decreases in pH reflecting less influence on the water chemistry from the longer residence time epikarst or and matrix waters, and greater impact from the more dilute, newly recharged waters. Due to the complexity of karst flow and temporal variations in flow and chemistry, controls on turbidity are not consistent through time and space at the wells. During smaller storms. recharge by lower ionic strength waters may promote colloid release and thus contribute to observed increases in turbidity. During larger storms, elevated turbidity may be more related to pH increases resulting from greater influx of matrix and soil waters into fractures and conduits. Chemical factors alone cannot account for the changes in turbidity observed during the various storms. Because of the complicated nature of flow and particle transport in karst aquifers, the presence of colloids during precipitation events is dictated by a complex interplay of chemical reactions and the effects of physical perturbations due to increased flow through the conduits and fractures. Simple trends in water quality parameters could not be identified, and broad generalizations cannot easily be made in karst settings, and some of the expected correlations between chemical parameters during the storms were not observed in this work. (C) 2002 Elsevier Science B.V. All rights reserved

Phosphorus mobility in a karst landscape under pasture grazing system, 2003, Allousha Ga, Boyer Dg, Belesky Dp, Halvorson Jj,
The spatial distribution and partitioning of water dissolved phosphorus fractions in the soil profile of a grazed karst sinkhole landscape were investigated. We also measured P fractions in surface runoff entering a sinkhole drain and in karst spring flow draining the study area. Grazing increased total N, C, and all forms of P of soil. Dissolved inorganic orthophosphate (DPi) was the highest in the surface soil layer and diminished significantly with depth. The proportion of dissolved unreactive phosphorus (DPu) increased with soil depth. Changes in DPu with landscape position and depth were closely correlated with changes in dissolved organic carbon (DOC) suggesting that the mobility and transport of DPu was mediated by DOC. Landscape position sampling showed molybdate reactive phosphorus (MRP) and DPu increased toward the bottom and center of sinkholes. The distribution of DPi and DPu in surface runoff and that occurring in underground watercourses confirms the significance of DPu transported into karst groundwater

Total Organic Carbon (TOC) and magnesium (Mg2): two complementary tracers of residence time in karstic systems, 2003, Batiot C, Emblanch C, Blavoux B,
The Total Organic Carbon (TOC) is an interesting tracer of fast infiltration within karstic systems [3,7]. Regular sampling on several aquifers. from the experimental site of Vaucluse, made it possible to demonstrate the high sensitivity of this tracer compared with other commonly used chemical and isotopic tracers in karstic hydrogeology. The complementarity of magnesium, indicator of the residence time of water within the system, and TOC appears as a relevant tool in order to characterize the behaviour of the aquifer, to differentiate the water types which participate to the karstic flow (fast infiltration, unsaturated zone, saturated zone) and then, to evaluate their vulnerability. (C) 2003 Academie des sciences/Editions scientifiques et medicales Elsevier SAS. All rights reserved

Dissolved organic carbon in precipitation, throughfall, stemflow, soil solution, and stream water at the Guandaushi subtropical forest in Taiwan, 2003, Liu C. P. , Sheu B. H. ,
The concentration and flux of dissolved organic carbon (DOC) were measured in precipitation, throughfall, stemflow, soil solution, and stream water for three types of subtropical forest stands, a Chinese fir (Cunninghamia lanceolata) plantation, a secondary hardwood, and a natural hardwood stand in Guandaushi forest in central Taiwan from January 1998 to December 1998. The mean DOC concentration in precipitation was 4.7 mg l(-1). However, in the rain passing through the tree canopies and barks as throughfall and stemflow, the mean concentrations were 7.0 and 30.8, 9.9 and 10.0, and 8.3 and 7.2 mg l(-1) in the Chinese fir plantation, the secondary hardwood, and the natural hardwood, respectively. Mean DOC concentrations in soil solution were lower in the Chinese fir plantation than both hardwoods, and decreased with depth of soil profiles. Stemflow DOC flux (132.4 kg ha(-1)) in the Chinese fir plantation was much higher than the other hardwood stands (15.3 and 6.7 kg ha(-1) in secondary and natural hardwood, respectively). The monthly variations of DOC concentrations were very similar in throughfall and stemflow at the three stands, showing an increase in the beginning of the growing season in April. No clear monthly variations in soil solution DOC concentrations (mean from 3.2 to 21.3 mg l(-1) in different stands and for different depths) were found in our study. DOC concentrations (mean 2.7 mg l(-1)) in the stream draining the watershed were higher in spring and in winter. (C) 2002 Elsevier Science B.V. All rights reserved

Bacterial diversity and ecosystem function of filamentous microbial mats from aphotic (cave) sulfidic springs dominated by chemolithoautotrophic 'Epsilonproteobacteria', 2004, Engel As, Porter Ml, Stern La, Quinlan S, Bennett Pc,
Filamentous microbial mats from three aphotic sulfidic springs in Lower Kane Cave. Wyoming. were assessed with regard to bacterial diversity, community structure, and ecosystem function using a 16S rDNA-based phylogenetic approach combined with elemental content and stable carbon isotope ratio analyses. The most prevalent mat morphotype consisted of while filament bundles, with low C:N ratios (3.5-5.4) and high sulfur content (16.1-51.2%). White filament bundles and two other mat morphotypes organic carbon isotope values (mean delta(13)C = -34.7parts per thousand: 1sigma = 3.6) consistent with chemolithoautotrophic carbon fixation from a dissolved inorganic carbon reservoir (cave water, mean delta(13)C = -7.47parts per thousand for two springs, n = 8). Bacterial diversity was as low overall in the clone libraries, and the most abundant taxonomic group was affiliated with the 'Epsilonproteobacteria' (68%) with other bacterial sequences affiliated with Gammaproteobacteria (12.2%), Betaproteobacteria (11.7%), Deltaproteobacteria (0.8%), and the Acidobacterium (5.6%) and Bacteriodetes/Chlorobi (1.7%) divisions. Six distinct epsilonproteobacterial taxonomic groups were identified from the microbial mats. Epsilonproteobacterial and bacterial group abundances and community structure shifted front the spring orifices downstream. corresponding to changes in dissolved sulfide and oxygen concentrations and metabolic requirements of certain bacterial groups. Most of the clone sequences for epsilonproteobacterial groups were retrieved from areas with high sulfide and low oxygen concentrations, whereas Thiothrix spp. and Thiobacillus spp. had higher retrieved clone abundances where conditions of low sulfide and high oxygen concentrations were measured. Genetic and metabolic diversity among the 'Epsilonproteobacteria' maximizes overall cave ecosystem function, and these organisms play a significant role in providing chemolithoautotrophic energy to the otherwise nutrient-poor cave habitat. Our results demonstrate that sulfur cycling supports subsurface ecosystem through chemolithoautotrophy and expand the evolutionary and ecological views of 'Epsilonproteobacteria' in terrestrial habitats. (C) 2004 Federation of European Microbiological Societies. Published by Elsevier BY. All rights reserved

Storm pulse chemographs of saturation index and carbon dioxide pressure: implications for shifting recharge sources during storm events in the karst aquifer at Fort Campbell, Kentucky/Tennessee, USA, 2004, Vesper D. J. , White W. B. ,
Continuous records of discharge, specific conductance, and temperature were collected through a series of storm pulses on two limestone springs at Fort Campbell, western Kentucky/Tennessee, USA. Water samples, collected at short time intervals across the same storm pulses, were analyzed for calcium, magnesium, bicarbonate, total organic carbon, and pH. Chemographs of calcium, calcite saturation index, and carbon dioxide partial pressure were superimposed on the storm hydrographs. Calcium concentration and specific conductance track together and dip to a minimum either coincident with the peak of the hydrograph or lag slightly behind it. The CO2 pressure continues to rise on the recession limb of the hydrograph and, as a result, the saturation index decreases on the recession limb of the hydrograph. These results are interpreted as being due to dispersed infiltration through CO2-rich soils lagging the arrival of quick-flow from sinkhole recharge in the transport of storm flow to the springs. Karst spring hydrographs reflect not only the changing mix of base flow and storm flow but also a shift in source of recharge water over the course of the storm

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