Karst and Cave RSS news feed Like us on Facebook! follow us on Twitter!
Community news

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. ...

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. ...

Speleology in Kazakhstan

Shakalov on 11 Jul, 2012
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 live cave is cave in which there is river action or active deposition of speleothems. compare active cave [10].?

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

What is Karstbase?



Browse Speleogenesis Issues:

KarstBase a bibliography database in karst and cave science.

Featured articles from Cave & Karst Science Journals
Chemistry and Karst, White, William B.
Engineering challenges in Karst, Stevanović, Zoran; Milanović, Petar
See all featured articles
Featured articles from other Geoscience Journals
Geochemical and mineralogical fingerprints to distinguish the exploited ferruginous mineralisations of Grotta della Monaca (Calabria, Italy), Dimuccio, L.A.; Rodrigues, N.; Larocca, F.; Pratas, J.; Amado, A.M.; Batista de Carvalho, L.A.
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
See all featured articles from other geoscience journals

Search in KarstBase

Your search for nutrient (Keyword) returned 51 results for the whole karstbase:
Showing 1 to 15 of 51
Biology and ecology of the El Convento cave-spring system (Puerto Rico)., 1974, Nicholas Brother G.
The El Convento Cave-Spring System is located at the head of the Quebrada de Los Cedros, approximately 20 km. west of Ponce, southwestern Puerto Rico. Although situated in an arid environment, the gorge receives sufficient moisture from the cave-spring system to support an abundant flora, with Bucida buceras and Bursera simaruba as the dominant trees. The cave is frequently flooded and possesses a rich nutrient substrate in the form of bat guano. Numerous orthopterans (Aspiduchus cavernicola and Amphiacusta annulipes), decapoda (Macrobrachium carcinus and Epilobocera sinuatifrons), and chiroptera (Brachyphylla cavernarum and Artebius jamaicensis) are present. In addition, approximately a dozen other species of invertebrates are found in lesser abundance throughout the system. None of the forms collected demonstrated specific cavernicolous adaptations. Because of the numerous entrances and frequent flooding the possibility of the presence of troglobites is minimal.

The role of groundwater in eutropication of a lake in glacial outwash terrain., 1976, Lee David Robert
The nutrient contribution of groundwater in glacial outwash terrain was evaluated at Lake Sallie in north-central U.S.A. (4646' N., 95 54' W.). Groundwater entering the lake was collected with seepage meters consisting of bottomless cylinders vented to a thin membrane bag. A theoretical flow net and comparison of nutrient concentrations in well and seepage water indicated that seepage meters can be used in high velocity discharge areas to obtain site-specific water samples of groundwater for nutrient analyses. Based on an average value of 0.25 mg/l PO4, groundwater inflow along an 800 km segment of shoreline transported 37 kg of phosphorus per year into the lake. Groundwater inflow was nitrate rich along shoreline adjacent so land used for agriculture and lakeside septic tanks, but there was no apparent pattern regarding land use and phosphorus content of groundwater inflow. A nearby eutrophic lake was a suspected source of phosphorus in groundwater inflow. Because surface flow has carried large quantities of nitrogen and phosphorus into this lake, its present eutrophic condition cannot be attributed to nutrient influx by groundwater. However, groundwater nutrient influx could be highly significant in other lakes where surface nutrient influx is small.

The animal population of the hyporheic interstitial in a primary rock stream under the influence of the supply of allochthonous organic matter., 1976, Pieper Hansgerd
The Mettma, a mountain stream in the Black Forest, W. Germany, was investigated for effects of input of nutrients and energy by domestic waste water and effluent from a brewery introduced at one specific point. The investigation time ranged from May 1970 to February 1971. Initially, there is an impoverishment and structural changes of the biocoenosis in the hyporheic interstitial. There is an almost complete O2-depletion immediately after the waste water has been added. In winter, temperatures in the interstitial were higher than those in the current. No direct correlation between population densities and amount of organic matter were observed where allochthonous nutrients had been added. Population densities of multicellular animals were from 0 to 1.2 X 105 per 0.1 m3 of sediment. 4.1 km further downstream the fauna is similar to that above the waste water inlet, while at 7.35 km downstream of it is slightly less dense.

Mayan Urbanism: Impact on a Tropical Karst Environment, 1979, Deevey Es, Rice Ds, Rice Pm, Vaughan Hh, Brenner M, Flannery Ms,
From the first millennium B.C. through the 9th-century A.D. Classic Maya collapse, nonurban populations grew exponentially, doubling every 408 years, in the twin-lake (Yaxha-Sacnab) basin that contained the Classic urban center of Yaxha. Pollen data show that forests were essentially cleared by Early Classic time. Sharply accelerated slopewash and colluviation, amplified in the Yaxha subbasin by urban construction, transferred nutrients plus calcareous, silty clay to both lakes. Except for the urban silt, colluvium appearing as lake sediments has a mean total phosphorus concentration close to that of basin soils. From this fact, from abundance and distribution of soil phosphorus, and from continuing post-Maya influxes (80 to 86 milligrams of phosphorus per square meter each year), which have no other apparent source, we conclude that riparian soils are anthrosols and that the mechanism of long-term phosphorus loading in lakes is mass transport of soil. Per capita deliveries of phosphorus match physiological outputs, approximately 0.5 kilogram of phosphorus per capita per year. Smaller apparent deliveries reflect the nonphosphatic composition of urban silt; larger societal outputs, expressing excess phosphorus from deforestation and from food waste and mortuary disposal, are probable but cannot be evaluated from our data. Eutrophication is not demonstrable and was probably impeded, even in less-impacted lakes, by suspended Maya silt. Environmental strain, the product of accelerating agroengineering demand and sequestering of nutrients in colluvium, developed too slowly to act as a servomechanism, damping population growth, at least until Late Classic time

Groundwater chemistry and cation budgets of tropical karst outcrops, Peninsular Malaysia, I. Calcium and magnesium, 1989, Crowther J,
The discharge and chemical properties of 217 autogenic groundwaters were monitored over a 1-yr period in the tower karsts of central Selangor and the Kinta Valley, and in the Setul Boundary Range. Because of differences in soil PCO2, calcium concentrations are significantly higher in the Boundary Range (mean, 82.5 mg l-1) than in the tower karst terrain (44.6 mg l-1). Local differences in both source area PCO2 and amounts of secondary deposition underground cause marked intersite variability, particularly in the tower karst. Dilution occurs during flood peaks in certain conduit and cave stream waters. Generally, however, calcium correlates positively with discharge, since the amount of secondary deposition per unit volume of water decreases at higher flows. Magnesium concentrations and Mg:Ca Mg ratios of groundwaters are strongly influenced by bedrock composition, though bedrock heterogeneity and the kinetics and equilibria of carbonate dissolution reactions preclude extremely low or high Mg:Ca Mg values. Net chemical denudation rates range from 56.6 to 70.9 m3km2yr-1.The results are considered in relation to cation fluxes in surface runoff, soil throughflow and nutrient cycling. Preliminary calcium and magnesium budgets show that (1) dissolutional activity is largely confined to the near-surface zone; and (2) the annual uptake of calcium and magnesium by tropical limestone forests is similar in magnitude to the net solute output in groundwaters

Carbonate chemistry of surface waters in a temperate karst region: the southern Yorkshire Dales, UK, 1992, Pentecost Allan,
A detailed study of surface water chemistry is described from an important limestone region in northern England. Major ions and pH were determined for 485 sites (springs, seeps, streams, rivers and lakes) during summertime. The saturation state of the waters with respect to calcite was determined as the calcite saturation ratio ([Omega]). An unexpectedly large number of samples were found to be supersaturated (65.5% of the 268 km of watercourses surveyed). As a consequence, several streams entering major cave systems were incapable of further limestone solution, at least during periods of low flow. Many waters were supersaturated from their source and some deposited travertine. A significant negative correlation was found between spring discharge and both ([Omega]) and pH. Supersaturation was caused primarily by atmospheric degassing, with some contribution from aquatic plant photosynthesis.The median total dissolved inorganic carbon and Ca concentrations were 2.49 and 1.35 millimoles 1-1 respectively. Calcium originated exclusively from limestone, and carbon dioxide mainly from the soil and dissolved limestone. South facing catchments provided springwaters with significantly higher levels of TDIC and Ca when compared with north facing catchments. The study suggests that acid rain made a measurable contribution to limestone dissolution.Carboniferous limestone denudation rates were estimated as 54 to 63 m3 km-2 a-1 (54 to 63 mm 1000 years-1). About 50% of the Mg came from limestone and the remainder, together with most K, Na, SO4 and Cl from precipitation.Concentrations of dissolved nutrients were low, medians for NO3, NH4, total PO4 and SiO3 were 24 [mu]mol, 1.4 [mu]mol, 0.64 [mu]mol and 15.5 [mu]mol 1-1 respectively. The concentration of a further 23 trace elements was determined

Lechuguilla Cave is a deep, extensive, gypsum- and sulfur-bearing hypogenic cave in Carlsbad Caverns National Park, New Mexico, most of which (> 90%) lies more than 300 m beneath the entrance. Located in the arid Guadalupe Mountains, Lechuguilla's remarkable state of preservation is partially due to the locally continuous Yates Formation siltstone that has effectively diverted most vadose water away from the cave. Allocthonous organic input to the cave is therefore very limited, but bacterial and fungal colonization is relatively extensive: (1) Aspergillus sp. fungi and unidentified bacteria are associated with iron-, manganese-, and sulfur-rich encrustations on calcitic folia near the suspected water table 466 m below the entrance; (2) 92 species of fungi in 19 genera have been identified throughout the cave in oligotrophic (nutrient-poor) ''soils'' and pools; (3) cave-air condensate contains unidentified microbes; (4) indigenous chemoheterotrophic Seliberius and Caulobacter bacteria are known from remote pool sites; and (5) at least four genera of heterotrophic bacteria with population densities near 5 x 10(5) colony-forming units (CFU) per gram are present in ceiling-bound deposits of supposedly abiogenic condensation-corrosion residues. Various lines of evidence suggest that autotrophic bacteria are present in the ceiling-bound residues and could act as primary producers in a unique subterranean microbial food chain. The suspected autotrophic bacteria are probably chemolithoautotrophic (CLA), utilizing trace iron, manganese, or sulfur in the limestone and dolomitic bedrock to mechanically (and possibly biochemically) erode the substrate to produce residual floor deposits. Because other major sources of organic matter have not been detected, we suggest that these CLA bacteria are providing requisite organic matter to the known heterotrophic bacteria and fungi in the residues. The cavewide bacterial and fungal distribution, the large volumes of corrosion residues, and the presence of ancient bacterial filaments in unusual calcite speleothems (biothems) attest to the apparent longevity of microbial occupation in this cave

The nutritional status of healthy and declining stands of Banksia integrifolia on the Yanakie Isthmus, Victoria, 1997, Bennett Lt, Attiwill Pm,
Banksia integrifolia L.f. has been in decline an calcareous sands of the Yanakie Isthmus, southern Victoria, since early 1980. Early studies indicated that the decline is associated with a particular soil condition possibly a nutritional imbalance involving Fe. However, in foliage samples collected from the three main soil types of the Isthmus, declining trees had similar concentrations of Fe but lower concentrations of Ca than healthy trees. Comparisons were made of seasonal variation in concentrations of macro- and micro-nutrients in foliage and litterfall from healthy trees (to minimise secondary changes associated with decline) within healthy and declining sites on the same soil type. On average, litterfall and the nutrient content of litterfall was greatest within the canopy area of B. integrifolia of the healthy stand. Banksias of the healthy stand also had greater concentrations of N, P, K and Na in fully-expanded leaves, resorbed greater proportions of phloem-mobile nutrients from senescent leaves and accumulated more Ca in senescent leaves. However, there was no evidence of nutritional imbalance in healthy trees within declining stands. It is argued that the lower foliar Ca in declining trees on three soil types and lower nutritional status of healthy trees within declining stands were due to lower productivity and lower water use and were therefore a result or an indication of decline rather than a cause

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

Bats of Kartchner Caverns State Park, Arizona, 1999, Buecher, D. C. , Sidner, R. M.
Kartchner Caverns, in southeastern Arizona, is a summer maternity roost for approximately 1000-2000 cave myotis (Myotis velifer). The pregnant females first arrive at the cave in late April, give birth in June, and have left by mid- September. These bats are an important element in the cave ecosystem because their excrement introduces nutrients, which support a complex invertebrate cave fauna. Bat population densities and emergence behavior was monitored between 1988-1991. Other bat species seen using the entrance areas of the cave include Corynorhinus townsendi and Choeronycteris mexicana. Because bats are easily disturbed by human intrusion into the roost, the baseline study was accomplished using low-disturbance techniques in an effort to provide the greatest amount of data with the least disturbance to the bat colony. These techniques included limited visual observations in the roost and netting bats only on the surface at a nearby water tank. During the baseline study, an episode of predation by a carnivore (Bassariscus astutus) caused the bats to abandon the site for a short time. Carbon-14 dating of guano from the Throne and Rotunda Rooms suggests that Myotis velifer used the Back Section of Kartchner Caverns 50-45 years Ka.

Research on the soils of karst areas in Hungary (example from Bükk Mountain), 1999, Zseni Anikó,

The author studied the characteristics of the soil nutrient system in a Hungarian karst area, that is on 8 km2 area of the Bükk plateau. The pH, total carbonate content, total soil-nitrogen content, plant available calcium, potassium, magnesium, and phosphorus contents of 63 soil samples were measured. She was able to compare the nutrient system of the soils which occurred in different ecological conditions. There are differences between the nutrient status of the soils of the beech and pine forest and the open fields. The knowledge of the pH plus the N, P, K, Ca, Mg content of the soils can be important regarding the protection of the environment, the maintenance of the forest and the management of the meadows.

Carbonate platform systems: components and interactions -- an introduction, 2000, Insalaco Enzo, Skelton Peter, Palmer Tim J. ,
Carbonate platforms are open systems with natural boundaries in space and time. Across their spatial boundaries there are fluxes of energy (e.g. light, chemical energy in compounds, and kinetic energy in currents and mass flows) and matter (e.g. nutrients, dissolved gases such as CO2, and sediment -- especially, of course, carbonates). Internally, these fluxes are regulated by myriads of interactions and feedbacks (Masse 1995), and the residue is consigned to the geological record. The most distinctive aspect of carbonate platforms is the predominant role of organisms in producing, processing and/or trapping carbonate sediment, even in Precambrian examples. Because of evolutionary changes in this strong biotic input, it is harder to generalize about carbonate platforms than about most other sedimentary systems. Evolution has altered both the constructive and destructive effects of platform-dwelling organisms on carbonate fabrics, with profound consequences for facies development. Moreover, changing patterns in the provision of accommodation space (e.g. between greenhouse and icehouse climatic regimes) have also left their stamp on facies geometries, in turn feeding back to the evolution of the platform biotas. Hence simplistic analogies between modern and ancient platforms may give rise to misleading interpretations of what the latter were like and how they formed. Although a number of carbonate platform and reef specialists have warned of the dangers of such misplaced uniformitarianism (e.g. Braithwaite 1973; Gili et al. 1995; Wood 1999), it remains depressingly commonplace in the literature on ancient carbonate platforms. The endless quest in the literature for an allpurpose definition of reefs' ... This 250-word extract was created in the absence of an abstract

17 beta-estradiol as an indicator of animal waste contamination in mantled karst aquifers, 2000, Peterson E. W. , Davis R. K. , Orndorff H. A. ,
The poultry and cattle industries comprise a large segment of the agricultural economy in the mantled karst area of northwest Arkansas. The associated risks of nutrient and bacterial contamination to karst aquifers by poultry litter have been well documented. However, only recently have the risks associated with hormones, specifically 17 beta-estradiol (E-2), been addressed. During a winter recharge event, five springs in northwest Arkansas were sampled and the waters were analyzed for E-2, fecal coliform, and Escherichia coli. Analyses of the waters from five springs representing three different water-bearing formations revealed that E2 is present in the waters. Concentrations of E-2 ranged from 6 to 66 ng/L. The observed E-2 concentration trends imitated the changes in stage over the recharge event. The EI concentration trends were similar to the concentration trends of both fetal coliform and E. coli at all five springs, indicating that the three components move in the mantled karst system similarly

Mn-Fe deposits in shallow cryptic marine environment: examples in northwestern Mediterranean submarine caves, 2001, Allouc J, Harmelin Jg,
Black coating of hard substrates by Mn and Fe oxides has long been reported from shallow, dark, submarine caves. However, these littoral metallic deposits have never been studied in detail, despite expected analogies with deep-sea polymetallic crusts. Submarine caves are characterized by darkness and low rates of exchanges with the open sea. Lack of primary production and confinement of inner water bodies result in marked oligotrophy and extremely reduced biomass, i.e. conditions close to those prevailing in deep-sea habitats. Field evidences suggested that the formation of Mn-Fe coatings was closely tied to these particular environmental conditions. The goal of this study was to examine the detailed features of Mn-Fe coatings from dark caves with different local conditions, and to try to identify the processes responsible for their deposition. Study sites and methods Three sublittoral, single-entrance, caves were sampled by scuba diving along the coasts of Provence (France, Mediterranean Sea) (fig. 1). The first site is a large karstic cave (Tremies Cave, 16 m depth at entrance floor, 60 m long; Marseille-Cassis area) with an ascending profile which results in a buffered thermal regime and markedly oligotrophic conditions due to warm water trapping in its upper part (fig. 1 and 2). Wall fragments were sampled at 30 m (medium confinement : zone B) and 60 in (strong confinement : zone C) from the cave entrance. The second site is a large tubular cavity open in conglomerate formations (3PP Cave, 15 m depth at entrance floor, 120 m long; La Ciotat) with a descending profile which results in relative permanence of winter temperatures within the inner parts, complex water circulation and presumed greater input of sedimented particles than in the preceding cave (fig.1 and 2). Wall samples were taken at 25 m, 70 in and 100 m from entrance. The third site is a small, horizontal, cave open in quartzite formations (Bagaud Cave, 7 in depth at entrance floor, about 10 m long; WNW of Port-Cros Island, bay of Hyeres). Sampling was performed on walls of a narrow corridor between an anterior room and a smaller inner room. A sporadic outflow of continental waters is located in the inner room. The samples were preserved in 50% ethylic alcohol or studied soon after their sampling. Before carbon coating and SEM examination, or microanalyses with SEM-associated spectrometers, they were treated in a 33% Chlorox solution and thereafter washed in demineralized water and dried. Micromorphology At low-medium magnification (<20,000), the aspect of coatings varies between caves and, especially, between inner-cave locations. All the described structures are made up of Mn and Fe oxides. In Tremies Cave, coatings of walls from zone B are composed of irregular erected constructions (height : 10s to 100s μm) formed by the aggregation of roughly ovoid primary concretions of about 10 μm (fig. 3). The surface of those primary concretions displays numerous lacunose to reticulate films (pores, about 0.5 μm in diameter, are often subrounded). Remnants of these films and organomorphic corpuscles occur also within the primary concretions (fig. 4). On younger substrates (broken wall exposed since 1970), primary concretions are poorly developed and no prominent construction is visible (fig. 5). In more confined conditions (zone C), the erected constructions of ancient coatings are smaller and less numerous than in zone B but are well individualized (fig. 6). In this zone: C, besides some remnants of lacunose to reticulate films (fig. 7), there is an appearance of filaments and ovoid corpuscles (height/width : 10-30/5-15 μm), which seem to be linked to filaments by a short stalk (fig. 8). In 3 PP Cave, at 25-70 m from entrance, wall coatings present porous heaps of primary concretions (fig. 9). The surface and the inside of the latter comprise remnants of lacunose to reticulate films that evoke those observed in Tremies Cave (fig. 10 and 11). On younger substrates (hard parts of sessile invertebrates), coatings are restricted to micrometric organomorphic corpuscles with some remnants of lacunose or fibrous films (fig. 12). At 100 in from the entrance, coatings are shaped by numerous erected constructions, more or less coalescing (fig. 13). Besides remnants of lacunose films, the primary concretions contain interlacing filaments (diameter : 0.2-0.3 μm) forming cords or veils (fig. 14). In Bagaud Cave, the primary concretions are aggregated in irregular heaps (fig. 15). Lacunose films are particularly frequent and tend to form three-dimensional mamillated structures that were not observed in the other caves (fig. 16). In particular, there is an appearance of tubular structures (fig. 17) and of numerous hemispheroidal structures (diameter : 4-5 μm) with an upper orifice (fig. 18 and 19). At higher magnification (20,000), whatever the cave and inner-cave location, the aspect of oxide deposits is rather smooth or, especially, microgranular (fig. 20). Mineral composition The composition of coatings is different between caves and according to their inner-cave location. In both large caves (Tremies and 3 PP), the Mn/Fe ratio increases with the distance from the cave entrance, i.e. when exchanges with the open sea diminish (fig. 21a). This trend is particularly clear in Tremies Cave, where the confinement gradient is strongly marked. Besides, the Mn/Fe ratio also seems to increase when films are present in the analysed volume (some cubic micrometers) (fig. 21b). In Bagaud Cave, the Mn/Fe ratio reaches high values despite the small size of this cave and its low confinement level. Discussion and conclusions SEM observations suggest that in each studied cave, the Mn-Fe coatings are biosedimentary deposits. Genesis of these deposits is assumed to result mainly from the replacement of biofilms (composed of cells and slime, i.e, of extracellular polymeric substance produced by microorganisms) generated by microbial populations colonizing the cave walls. Considering the darkness of the cave-locations, microbes consist mainly in bacteria, but fungi are probably responsible for the filaments and ovoids corpuscules (evoking sporocysts) occurring in innermost parts. Observations at different scales of the morphological features of oxide deposits reveal a structured organisation which varies along the strong environmental gradients (particularly the confinement level) that occur from the entrance to the innermost parts : erected constructions made up of primary concretions become more and more defined and acquire a pseudo-columnar shape. The aspect of biofilms appears to be controlled by the same environmental parameters. In open or relatively open environments, they frequently show a three-dimensional development (with frequent skullcape-like shapes), while in more confined conditions they exhibit a planar layout. These changes reflect either the adaptation of the slime-producing bacteria to the local trophic resources (correlated to the rate of exchange with the open sea) and water movements, or spatial replacement of taxa. It is assumed that slime (mainly composed of water and exopolysaccharides) induces a local increase of the concentration in dissolved Mn and acts as an ion exchange resin that allows the retention of Mn on the functional groups of EPS. These conditions promote the nucleation of Mn oxide crystallites in the slime. Then. the anionic character of Mn oxides in seawater, and their capacity to catalyse the oxydation of Mn2 to Mn4, allow the process to go on without any other biological intervention; thus, the process of crystal growth becomes possible. In caves where Mn is only supplied by seawater (Tremies and 3 PP), the average value of the Mn/Fe ratio of coatings is negatively correlated to the local availability of nutrients. This trend is probably linked to changes in the selectivity of slimes towards the processes of retention of cations, because this ratio is clearly influenced by the occurrence of biofilms. However, independently from trophic resources, the Mn/Fe ratio can be notably increased when additional Mn is provided by the seeping or flowing of continental waters (Bagaud Cave)

Geomicrobiology of caves: A review, 2001, Northup D. E. , Lavoie K. H. ,
In this article, we provide a review of geomicrobiological interactions in caves, which are nutrient-limited environments containing a variety of redox interfaces. Interactions of cave microorganisms and mineral environments lead to the dissolution of, or precipitation on, host rock and speleothems (secondary mineral formations). Metabolic processes of sulfur-, iron-, and manganese-oxidizing bacteria can generate considerable acidity, dissolving cave walls and formations. Examples of possible microbially influenced corrosion include corrosion residues (e.g., Lechuguilla and Spider caves, New Mexico, USA), moonmilk from a number of caves (e.g., Spider Cave, New Mexico, and caves in the Italian Alps), and sulfuric acid speleogenesis and cave enlargement (e.g., Movile Cave, Romania, and Cueva de Villa Luz, Mexico). Precipitation processes in caves, as in surface environments, occur through active or passive processes. In caves, microbially induced mineralization is documented in the formation of carbonates, moonmilk, silicates, clays, iron and manganese oxides, sulfur, and saltpeter at scales ranging from the microscopic to landscape biokarst. Suggestions for future research are given to encourage a move from descriptive, qualitative studies to more experimental studies

Results 1 to 15 of 51
You probably didn't submit anything to search for