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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. ...

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 particulate transport is the movement of particles in subsurface water [22].?

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Your search for divergence (Keyword) returned 19 results for the whole karstbase:
Showing 1 to 15 of 19
Genetic analysis of evolutionary processes, 1987, Wilkens Horst
Epigean and cave populations of A. fasciatus (Characidae, Pisces) differ in a series of morphological physiological, and ethological features. The interfertility of these populations made possible a genetic analysis of organs characteristic of interspecific divergence. The study of the regressive organs "eye" and "melanophore system" on the one hand and that of the constructively improved "gustatory equipment and feeding behaviour" on the other yielded identical principles of genetic manifestation: (1) All features have a polygenic basis with an at least di- to hexahybrid inheritance. (2) All polygenes have the same amount of expressivity. (3) After recombination of a minimum number of genes, discontinuous distributions (threshold effects) develop. (4) All features are independently inherited. (5) The genes responsible for a feature are unspecific. In the case of the eye this means that no "lens-" or "retinagenes" are analyzed; due to developmentally physiological interdependence within complex structures, only so-called "eye-genes" have as yet been described. Because of the developmentally physiological interdependence of complex organs, the process of reduction proceeds as a diminution in size, that of constructive evolution as enlargement. In both cases different allometric correlations of the single structures can be found. The convergent reduction of eyes in cave animals is caused by the loss of stabilizing selection which normally keeps the eye in its appropriate adapted form. It is not directional selection pressure, like f. ex. energy economy, but mutation pressure that causes eye reduction. By this, random mutations, which are mostly of deleterious character, are accumulated. The principles of regressive evolution are not restricted to the development of cave species. The absence of stabilizing selection regularly occurs during transitional evolutionary phases. These are f. ex. initial stages of speciation which may be observed when biotopes with little or no interspecific competition are colonized by an invader. Genotypic and phenotypic variability now arise and equilibria become punctuated, because stabilizing selection for a specific ecological niche which has once been acquired by the invading species is no longer acting. Examples include the evolution of species flocks in geologically young lakes or oceanic islands. Rapidly increasing variability now secondarily provides the material for directional selection which radiates such species into vacant niches. Genetic threshold effects as described above may accelerate this process. Variability will finally become lower again under the influence of inter- and intraspecific competition. A new equilibrium is attained.

Evolutionary genetics and morphometrics of a cave crayfish population from Chiapas (Mexico), 1988, Allegrucci Giuliana, Baldari Fabiola, Cesaroni Donatella, Sbordoni Valerio
The recently explored Cueva de Los Camarones, in the remote village of Constitucion, Chiapas, Mexico, houses a unique highly variable population of Procambarus crayfish (Crustacea, Decapoda). Morphologically, a more or less clinal variation is revealed at several features such as the degree of rudimentation in both pigmentation and eye, and the elongation of body and appendages. Extremes are quite different, ranging from typical dark, thick, eyed individuals to light, elongated, microphtalmic phenotypes. Evolutionary relationships among individuals were investigated electrophoretically (25 structural gene loci) and morphometrically (12 characters) by means of multivariate analyses. Results from analysis of individual allozymic multilocus profiles indicate that the "light" phenotypes belong to a distinct gene pool with respect to the "dark" ones, but some level of introgression is hypothesized. Results from analysis of individual morphometric profiles also show a discrimination between light and dark samples, chiefly determined by the shape of the rostrum and chela. The existence of such a discontinuous variation both in morphometric and allozymic characters presumably reflects a history of allopatric divergence followed by secondary contact of the two species.

Geographic variation and genetic relationships in populations of the Androniscus dentiger complex from Central Italy (Isopoda, Oniscidea, Trichoniscidae), 1997, Allegrucci Giuliana, Gentile Gabriele
Androniscus dentiger is a terrestrial isopod distributed from Great Britain to North Africa, inhabiting humid edafic environments, superficial underground compartments and both natural and artificial caves. In this study allozyme data have been used to investigate the geographic variation and the genetic relationships of several populations of A. dentiger from Central Italy, using as outgroups populations from four congeneric species, A. calcivagus, A. cfr. subterraneus, A. spelaeorum, and A. degener. Multivariate analysis of A. dentiger allele frequencies indicates the existence of a group of populations (group A) distributed in a wide geographic area which are genetically slightly differentiated, and several populations (arbitrarily defined as group B) which show differentiation levels comparable to those observed between the morphologically well differentiated species. The low valley of the river Tiber seems to act as an effective geographic barrier between the populations from group A and the remaining ones. The genetic divergence between populations within the group A seems to have a recent origin. This is suggested by the low genetic distances and heterozygosity values within the group A, and by the very low number of private alleles occurring in this group. The high degree of intraspecific and interspecific genetic differentiation is not consistent with the levels of morphological differentiation traditionally used to distinguish different species within this genus. On the whole, these data suggest that A. dentiger might be considered as a complex of cryptic/sibling species.

Genetic divergence and evolutionary times: calibrating a protein clock for South-European Stenasellus species (Crustacea, Isopoda), 1997, Argano Roberto, Sbordoni Marina Cobolli, Matthaeis Elvira De, Ketmaier Valerio
We studied genetic divergence in a group of exclusively stygobiont isopods of the family Stenasellidae. In particular, we assessed evolutionary relationships among several populations of Stenasellus racovitzai and Stenasellus virei. To place this study in a phylogenetic context. we used another species of Stenasellus, S. assorgiai, as an outgroup. S. racovitzai occurs in Corsica, Sardinia and in the fossil islands of the Tuscan Archipelago, while S. virei is a polytypic species widely distributed in the central France and Pyrenean area. This vicariant distribution is believed to be the result of the disjunction of the Sardinia-Corsica microplate from the Pyrenean region and its subsequent rotation. Since geological data provide time estimates for these events, we can use the genetic distance data to calibrate a molecular clock for this group of stygobiont isopods. The calibration of the molecular clock reveals a roughly linear relationship (r = 0.753) between the genetic distances and absolute divergence times, with a mean divergence rate (19.269 Myr/DNei,) different from those previously reported in the literature and provides an opportunity to shed some light on the evolutionary scenarios of other Stenasellus species.

The Hawaiian cave planthoppers (Homoptera: Fulgoroidea: Cixiidae); A model for rapid subterranean speciation?, 1997, Hoch Hannelore
After the successful colonization of a single ancestral species in the Hawaiian Islands, planthoppers of the cixiid genus Oliarus underwent intensive adaptive radiation resulting in 80 described endemic species. Oliarus habitats range from montaneous rain forests to dry coastal biotopes and subterranean environments. At least 7 independant evolutionary lines represented by different species have adapted to lava tubes on Molokai (1), Maui (3), and Hawaii Island (3). Behavioral and morphological studies on one of these evolutionary lines on Hawaii Island, the blind, flight- and pigmentless Oliarus polyphentus have provided evidence for reproductive isolation between allopatric populations which may in fact be separate species. Significant differences in song parameters were observed even between populations from neighbouring lava tubes, although the planthoppers are capable of underground migration through the voids and cracks of the mesocavernous rock system which is extant in young basalt: after a little more than 20 years, lava tubes within the Mauna Ulu 1974 flow had been colonized by O. 'polyphenius" individuals, most probably originating from a near-by forestkipuka. Amazingly, this species complex is found on the youngest of the Hawaiian Islands, with probably less than 0.5 m.y., which suggests rapid speciation processes. Field observations have led to the development of a hypothesis to match underground speciation with the dynamics of vegetational succession on the surface of active volcanoes. Planthopper range partitioning and geographic separation of populations by young lava flows, founder events and small population size may be important factors involved in rapid divergence.

Hydrogeology of glacial and subglacial karst aquifers: Small River, British Columbia, Canada., 1997, Smart C. C.
The Small River Glacier overlies two active conduit karst aquifers and has been studied to understand the nature of subglacial karst hydrology. Profoundly undersaturated surface meltwaters recharge the karst through moulins focused on the crest of large hummocks. Supraglacial traces reached karst springs faster than extraglacial waters, perhaps a result of paraglacial occlusion of sinks beyond the glacier margin. Glacier-karst flow routes were open channel and maintain very low (atmospheric) water pressures at the glacier bed. Variable divergence of replicate traces demonstrated that hydrogeographic divides were fuzzy and unstable. Divergence occurs through overflow and hydraulic switching rather than changes in the conduit. Subglacial flow followed a complex "submarginal" drainage system to the snout which gave highly anomalous hydraulic characteristics.

Parallel microgeographic patterns of genetic diversity and divergence revealed by allozyme, RAPD, and microsatellites in Triticum dicoccoides at Ammiad, Israel, 2000, Li You Chun, Fahima Tzion, Krugman Tamar, Beiles Avigdor, Der Marion S. , Korol Abraham B. , Nevo Eviatar,

Relationships between morphology, genetics and geography in the cave fruit bat Eonycteris spelaea (Dobson, 1871) from Indonesia, 2003, Maharadatunkamsi, Hisheh S. , Kitchener D. J. , Schmitt L. H. ,
Morphological and genetic analyses of Eonycteris spelaea from 15 islands along the Banda Arc, from Sumatra to Timor and including Kalimantan and Sulawesi, revealed considerable divergence between islands and geographical patterning. On the basis of both morphology and genetics, the populations on the large islands of Greater Sunda (Sumatra, Java, Kalimantan and Sulawesi) are generally distinct from one another and from those on the islands in Nusa Tenggara (Lombok to Timor), which form a more cohesive cluster. These differences may be the result of the Nusa Tenggara populations having been colonized more recently than those on the Greater Sunda, and probably from a single source. All biological measures of the relationships between island populations are positively associated with the extent of the sea-crossing between them, indicating the sea is an important barrier to movement. Multivariate analyses show the presence of a marked trend for body size to increase from west to east. However, individuals from Kalimantan are not consistent with this trend, being smaller than predicted, and on the two outer Banda Are islands of Sumba and Timor animals are a little larger than predicted from the longitudinal trend. These differences could be due to the relative isolation of these populations or differing environmental conditions. There is also a negative relationship between body size and island area, but this is confounded by the longitudinal trend. No significant longitudinal trends in the genetic data were detected and the trend in body size may be an adaptive response to an environmental cline that is known to occur in this region. (C) 2003 The Linnean Society of London

Dental morphology of the Dawenkou Neolithic population in North China: implications for the origin and distribution of Sinodonty, 2003, Manabe Y. , Oyamada J. , Kitagawa Y. , Rokutanda A. , Kato K. , Matsushita T. ,
We compare the incidence of 25 nonmetric dental traits of the people of the Neolithic Dawenkou culture (6300-4500 BP) sites in Shandong Province, North China with those of other East Asian populations. The Dawenkou teeth had an overwhelmingly greater resemblance to the Sinodont pattern typical of Northeast Asia than to the Sundadont pattern typical of Southeast Asia. Multidimensional scaling using Smith's mean measure of divergence (MMD) statistic place the Dawenkou sample near the Amur and the North China-Mongolia populations in the area of the plot indicating typical Sinodonty. The existence of the Sinodont population in Neolithic North China suggests a possible continuity of Sinodonty from the Upper Cave population at Zhoukoudian (about 34,000-10,000 BP) to the modern North Chinese. The presence of Sinodonty in Shandong Province shows that the Japan Sea and East China Sea were strong barriers to gene flow for at least 3000 years, because at this time the Jomonese of Japan were fully Sundadont. In addition, we suggest that the descendants of the Dawenkou population cannot be excluded as one of the source populations that contributed to sinodontification in Japan. (C) 2003 Elsevier Ltd. All rights reserved

Apports des mthodes hydrologiques dans la comprhension des coulements en pays calcaire : exemple des bas plateaux jurassiques du haut bassin de la Marne (France), 2004, Lejeune Olivier, Devos Alain
Hydrological methods for the study of river flows in limestone areas: the Marne basin in the Jurassic low plateaux (NE France) - We investigated the geographical heterogeneity of river flows in limestone areas in the upper Marne valley (interfluves of Marne-Aube and Marne-Meuse) by using the low water profiles, the modelling of discharges and the study of physicochemical parameters. We studied five basin-slopes belonging to the Marne-basin (4500 km2) and the measures were realised between 2001 and 2003 at the time of low water periods. We used an instrument (perche intgration type Pire) in order to measure the stream flows of river water. We also measured temperature and electrical conductivity in order to identify the origin of the water. The measures allowed us to identify low water profiles of the river and we also can map the discharge in low water periods. The methods show the water flow inside a basin-slope and also hydrogeological connections to the adjacent basin-slopes. Thus, they revealed that the divergence or the concentration of discharges depends on the limits of the aquifers sections related to their morphological structure and on the differential incision of the valleys. We obtained a hydrogeological pattern of interfluves and we can distinguish between areas of water lost and areas with an increasing of water volume. We confirmed this process of water transfers, called the active stream piracy, which is often approved by hydrogeologic tracers. This active stream piracy revealed by these methods in warm or interglacial period, prepare future stream piracy of surface, collectively recognised in the beginning of cold phase.

The Aubonne karst aquifer (Swiss Jura), 2005, Leutscher M. , Perrin J. ,
A synthesis of the hydrogeological investigations carried out in an important karst region of the Jura Mountains led to the recognition of a major hydrological system: the Aubonne-Toleure-Malagne system. The continuous monitoring of hydraulic parameters at the main outlets established a mean discharge of the system of more than 6 m(3)/s. A delimitation of the Aubonne catchment area is proposed in accordance with the water balance and the geology. Tracer tests outline the presence of a complex karst network which is closely related to the structural context. A schematic organisation of this network is proposed and a major divergence towards the nearby Montant system is set in evidence. Geological observations provide also evidences for a precise delineation of the catchment area: six major functional elements for the recharge of the aquifer are distinguished and transversal drainages towards the Aubonne spring system are outlined along major strike-slip faults. Combining hydrological information available on the Aubonne karst aquifer provides the indispensable background data for the management and the protection of this water resource

Le karst du dme anticlinal dAix-les-Bains : nouvelles donnes sur le panache hydrothermal, 2006, Gallino Stphanie
The karst of the anticlinal dome of Aix-les-Bains: New data on the hydrothermal plume - The springs Alun and Soufre open on the west side of the Aix-les-Bains anticline. The waters rise from 2200 m in depth and have traversed, through vertical joints, 1700m of limestones and the karstified Urgonien strata. This last rock layer causes a divergence in flow, because there are two springs, either clearly hydrothermal, or having hydrothermal characteristics, within 300 m in distance. The aim of this study is to show the relationship that may exist between these springs by tracing experiments, and thus to get an idea about the circulation in the terminal parts of the system. The tracing experiment shows a physical connection between the Alun and Soufre springs and a thermal sump called Therminator. It also allows to localize the upflow tube to be between Therminator and Alun.

Subterranean biogeography: what have we learned from molecular techniques?, 2007, Porter Megan L.
Subterranean faunas have unique distributional attributes, including relatively small ranges and high levels of endemism. Two general models have been proposed to account for these distributional patternsvicariance, the isolation of populations due to geographic barriers, and dispersal, an organisms ability to move to and colonize new habitats. The debate over the relative importance of each of these models in subterranean systems is ongoing. More recently, biogeographical studies of subterranean fauna using molecular methods have provided new perspectives into the distributional patterns of hypogean fauna, reinvigorating the vicariance versus dispersal debate. This review focuses on the application of molecular techniques to the study of subterranean biogeography, and particularly the contribution of molecular methods in estimating dispersal ability and divergence times. So far, molecular studies of subterranean biogeography have found evidence for the common occurrence of multiple independent colonizations of the subterranean habitat in cave-adapted species, have emphasized the importance of the genetic structure of the ancestral surface populations in determining the genetic structure of subsequent hypogean forms, and have stressed the importance of vicariance or a mixed model including both vicariant and dispersal events.

How long does evolution of the troglomorphic form take? Estimating divergence times in Astyanax mexicanus, 2007, Porter M. L. , Dittmar K. , Pé, Rezlosada M.

Features including colonization routes (stream capture) and the existence of both epigean and cave-adapted hypogean popula­tions make Astyanax mexicanus an attractive system for investi­gating the subterranean evolutionary time necessary for acqui­sition of the troglomorphic form. Using published sequences, we have estimated divergence times for A. mexicanus using: 1) two different population-level mitochondrial datasets (cyto­chrome b and NADH dehydrogenase 2) with both strict and relaxed molecular clock methods, and 2) broad phylogenetic approaches combining fossil calibrations and with four nuclear (recombination activating gene, seven in absentia, forkhead, and α-tropomyosin) and two mitochondrial (16S rDNA and cytochrome b) genes. Using these datasets, we have estimated divergence times for three events in the evolutionary history of troglomorphic A. mexicanus populations. First, divergence among cave haplotypes occurred in the Pleistocene, possibly correlating with fluctuating water levels allowing the coloni­zation and subsequent isolation of new subterranean habitats. Second, in one lineage, A. mexicanus cave populations expe­rienced introgressive hybridization events with recent surface populations (0.26-2.0 Ma), possibly also correlated with Pleis­tocene events. Finally, using divergence times from surface populations in the lineage without evidence of introgression as an estimate, the acquisition of the troglomorphic form in A. mexicanus is younger than 2.2 (fossil calibration estimates) – 5.2 (cytb estimate) Ma (Pliocene).


Molecular studies on the Niphargus kochianus group (Crustacea: Amphipoda: Niphargidae) in Great Britain and Ireland, 2008, Hanfling, Bernd, Isabel Douterelosoler, Lee Knight And Graham Proudlove.
he Niphargus kochianus group is one of the most westerly and northerly components of the genus Niphargus. All taxa within the group were delimited by morphological characters. However, recent research suggests that morphology alone is inadequate in determining species boundaries in troglobiotic organisms. We used two molecular markers to examine nucleotide diversity in two members of the N. kochianus group, and included other taxa from Genbank. The results indicate that N. kochianus kochianus and N. kochianus irlandicus are very divergent taxa, which have had no common ancestor since the Miocene. Since it is very difficult to reconcile this magnitude of divergence with a recent derivation of irlandicus from kochianus, and there has been a sea water barrier between Great Britain and Ireland for a long period we propose that irlandicus has been resident in Ireland throughout the Pleistocene glacial cycles. Survival in sub-glacial refugia is supported by the presence of species below ice in Iceland and Canada, by the favourable biotic and abiotic conditions under glaciers, and by the physiology of species in the genus. The taxon irlandicus should therefore be considered a separate species Niphargus irlandicus Schellenberg, 1932.

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