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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 loess is fine-grained and poorly consolidated windblown sediment, mainly of silt. great thicknesses of loess are found in areas marginal to hot and cold deserts, where the prevailing wind deposits fine dust particles blown from the desert basins or out of glaciofluvial sediments. loess is a common allogenic component of soils on limestones. large numbers of artificial caves have been excavated in the hillsides of soft loess in central china [9].?

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Featured articles from Cave & Karst Science Journals
Chemistry and Karst, White, William B.
Engineering challenges in Karst, Stevanović, Zoran; Milanović, Petar
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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
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Your search for traits (Keyword) returned 20 results for the whole karstbase:
Showing 1 to 15 of 20
Contribution on the study of European Bathynella: Bathynella natans Vejdovsky, a dilemma to resolve., 1966, Serban Eugne.
After a minute study of the structure of the 8th male pereiopod in some Bathynella populations from Romania and England, the structure differences which were found allowed to identify two well individualized kinds of pereiopods; they were named type natans and type stammen. Taking into account the striking differences between these two types, B. stammeri (Jakobi), which since 1954 is considered to be a subspecies of the natans species, was separated out of the species B. natans sensu Jakobi (1954). The populations understudied were collected in England and Romania, their minute study being the object of an other note, collaboration with T. Gledhill. The facts led to the conclusion that Jakobis opinion (1954), which dominated the taxonomy of this group, doesnt entirely correspond to the reality, the two taxonomical units being characterized as follows:; Bathynelta natans Vejdovsky, characterized by the 8th male pereiopod (fig. I A) with a triangular, well developed anterior plate (fig. 3 A-D-a; 7 A-D), of the same length with the exopodit, a cylindrical internal lobe (fig. 3 A-D-b,) and a little lobe (fig. 3 A-D-c) of a reduced size;; Bathynella stammeri (Jakobi) differing from the first with respect to the anterior pinte (fig. 2 A-D-a; 6A-C) which is rectangular in shape and has a prolongation in the distal outer angle, to the conelike internal lobe (fig. 2 AD-b), and to the little lobe (fig. 2 A-D-d) which is twolobed in this case. After discussion on the relationship between B. catena Vejd. and B. stammeri (Jakobi) it is shown that differences observed in the 8th male pereiopod structure give important indications about the above species to the effect that they are not very closely related. If one takes into account also their wide spreading area, and the individualisation of some populations due to important, characteristic traits; we are obliged to classify them into two different sub-genera. In the first one, the species catena is included; which will keep by this way the very name of the genus, and in the second, termed here Antrobathynella, the species stammeri. In conclusion, what was till now considered as Bathynella natans Vejdovsky sensu Jakobi, was divided into two distinct species each of them pertaining to two different sub-genera, that is: Bathynella (Bathynella) natans Vejdovsky and Bathynella (Antrobathynella) stammeri (Jakobi). It is demonstrated that the synonymy Jakobi made between B.chappuisi and B. natans is perfectly true under the new conditions too, because it was Delachaux (1919) who rediscovered B.natans Vejd., not Chappuis (1914). The material found by Chappuis in Basel (1914) appears to pertain to B. stammeri (Jakobi) differing both from the individuals from the Grotte de Ver (Delachaux, 1919) and from Prague (Vejdovsky, 1882).

Geomorphology and geologic structure; Straits of Florida, 1970, Malloy R. J. , Hurley R. J. ,
Bathymetric map, seismic reflection profiles, arcer profiles, bottom features, sediment distribution, faults, karst-like topography

Traits gnraux de l'hydrologie karstique en Basse Cvenne, 1984, Fabre, G.
GENERAL FEATURES OF KARSTIC HYDROLOGY IN BASSE CEVENNE (FRANCE) - N to the town of Als (SE Massif Central and Cvennes), a very fractured carbonated belt outcrops. The karst concerns some facies of Trias, Lias-Dogger, Upper Jurassic and Lower Cretaceous. Karstic flows are of two types: toward W, convergent to the important springs of la Tour-Dauthunes, and toward E and divergent. Ggeneral characteristics are presented. Economic aspect is pointed out, just as karstic stream piracy.

Genesis of a submarine sinkhole without subaerial exposure; Straits of Florida, 1995, Land Lewis A. , Paull Charles K. , Hobson Brett,
A sinkhole has been identified on side-scan sonar images and from near-bottom echo sounder data in the southern Straits of Florida in 575 m of water. Sinkholes are often thought to form exclusively in subaerial environments and for this reason have been used as indicators of sea level. This sinkhole exists within a Quaternary sediment apron in water depths too great to have been subaerially exposed by Neogene sea-level lowstands, thus indicating that sinkholes can develop within the submarine environment

Les deux faces de la pense de E.A. Martel., 1997, Choppy Jacques
Runion de textes de Martel: 1; Extraits du Nouveau Trait des Eaux Souterraines (1921), donnant l'essentiel de la pense de l'auteur sur l'hydraulique et la morphologie du karst. 2; En opposition cette vision, rappele de nombreuses fois par l'auteur, extraits de diverses publications (de 1894 1930), admettant qu'un fonctionnement en rgime noy tait possible: Martel est donc l'un des tout premiers ayant observ des formes de creusement en rgime noy, et les ayant interprtes comme telles.

Evaporite karst of northern lower Michigan, 1997, Black Tj,
Michigan has three main zones of evaporite karst: collapse breccia in Late Silurian deposits of the Mackinac Straits region; breccia, collapse sinks, and mega-block collapse in Middle Devonian deposits of Northern Lower Michigan, which overlaps the preceding area; and areas of soil swallows in sinks of Mississippian deposits between Turner and Alabaster in Arenac and Iosco counties, and near Grand Rapids in Kent County. The author has focused his study on evaporite karst of the Middle Devonian deposits. The Middle Devonian deposits are the Detroit River Group: a series consisting of limestone, dolomite, shale, salt, gypsum and anhydrite. The group occurs from subcrop, near the surface, to nearly 1400 feet deep from the northern tip of the Southern Peninsula to the south edge of the ''solution front'' Glacial drift is from zero to 350 feet thick. Oil and gas exploration has encountered some significant lost-circulation zones throughout the area. Drilling without fluid returns, casing seal failures, and lost holes are strong risks in some parts of the region. Lost fluid returns near the top of the group in nearby areas indicate some karst development shortly after deposition. Large and irregular lost-circulation zones, linear and patch trends of large sink holes, and 0.25 mile wide blocks of down-dropped land in the northern Lower Peninsula of Michigan were caused by surface- and ground-water movement along faults into the Detroit River Group. Glaciation has removed some evidence of the karst area at the surface. Sinkhole development, collapse valleys, and swallows developed since retreat of the glacier reveal an active solution front in the Detroit River Group

Submarine karst belt rimming the continental slope in the Straits of Florida, 2000, Land L. A. , Paull C. K. ,

Last glacial-Holocene paleoceanography of the Black Sea and Marmara Sea: stable isotopic, foraminiferal and coccolith evidence, 2002, Aksu Ae, Hiscott Rn, Kaminski Ma, Mudie Pj, Gillespie H, Abrajano T, Yasar D,
Multi-proxy data and radiocarbon dates from several key cores from the Black Sea and Marmara Sea document a complex paleoceanographic history for the last ~30[punctuation space]000 yr. The Marmara Sea was isolated from both the Black Sea and the Aegean Sea during glacial periods when global sea-level lowering subaerially exposed the shallow sills at the Straits of Bosphorus and Dardanelles (i.e. lake stage), and reconnected through both straits during interglacial periods, when rise of global sea level breached the shallow sills (i.e. gateway stage). Micropaleontological data show that during the `lake stage' the surface-water masses in both the Marmara Sea and Black Sea became notably brackish; however, during the `gateway stages' there was a low-salinity surface layer and normal marine water mass beneath. Two sapropel layers are identified in the Marmara Sea cores: sapropels M2 and M1 were deposited between ~29.5 and 23.5 ka, and ~10.5 and 6.0 ka, respectively. Micropaleontological and stable isotopic data show that the surface-water salinities were reduced considerably during the deposition of both sapropel layers M2 and M1, and calculation using planktonic foraminiferal transfer functions shows that sea-surface temperatures were notably lower during these intervals. The presence of fauna and flora with Black Sea affinities and the absence of Mediterranean fauna and flora in sapropels M1 and M2 strongly suggest that communication existed with the Black Sea during these times. A benthic foraminiferal oxygen index shows that the onset of suboxic conditions in the Marmara Sea rapidly followed the establishment of fully marine conditions at ~11-10.5 ka, and are attributed to Black Sea outflow into the Marmara Sea since 10.5 ka. These suboxic conditions have persisted to the present. The data discussed in this paper are completely at odds with the `Flood Hypothesis' of Ryan et al. (1997), and Ryan and Pitman (1999)

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

Lateglacial and Holocene sea level changes in semi-enclosed seas of North Eurasia: examples from the contrasting Black and White Seas, 2004, Kaplin Pavel A. , Selivanov Andrei O. ,
A comparison of the Black and White Seas, which differ in their tectonic, glacial and climatic history but which share a strong dependence upon limited water exchange with the world ocean, represents an opportunity for the identification of major factors controlling sea level changes during the Lateglacial and Holocene and for the correlation of these changes. Existing data were critically analyzed and compared with the results of geological, geomorphological and palaeohydrological studies obtained by the present authors during the past two decades.We conclude that glacioeustatic processes played a major role in relative sea level changes on most coasts of both areas. However, along several coastlines, other factors overwhelm glacioeustasy during some time intervals. In the Black Sea, water level rose from its minimum position, -100-120 m, at 18-17 ka BP, to -20-30 m at nearly 9 ka BP. In the White Sea, the decreasing trend in relative sea level is well illustrated on the Kola Peninsula and in Karelia, subject to glacioisostatic emergence. A drastic sea level fall from to -25 m occurred with the drainage of glacial lakes in the eastern White Sea (12.5-9.5 ka BP).The Black and White Sea histories changed drastically in the early Holocene or in the beginning of the middle Holocene (9.5-7.5 ka BP) due to the intrusion of water from the Mediterranean and the Barents seas, respectively. During this period, the White Sea developed under the strong influence of the formation of 'ice shelves' and 'dead ice' blocks, retreating glaciers, as well as of glacioisostatic and related processes. The Black Sea history, however, was determined by water exchange with the Mediterranean via the shallow Dardanelles and Bosporus straits (outflow from the Black Sea 10-9.5 ka BP and inflow from 9-7.5 ka BP according to various data), and, partially, by river discharge variations caused by climatic changes on the Russian Plain. The hypothesis of a catastrophic sea level rise from -120-150 to -15-20 m nearly 7550 calendar years BP is not supported by our data. Water intrusion from the Mediterranean was fast but not catastrophic.In the Black Sea, periods of high sea levels after the intrusion of Mediterranean waters are dated from four sedimentary complexes, Vityazevian, Kalamitian, Dzhemetian and Nymphaean, from nearly 7.5, 7-6, 5.5-4.5 and 2.2-1.7 ka BP, respectively. A fluctuating pattern of sea level change was established in the White Sea after the drainage of proglacial lakes and intrusion of ocean waters at the end of the early Holocene (nearly 8.5-8.2 ka BP). Major periods of sea level rise in the White Sea are dated from the late Boreal-early Atlantic (8.5-7.5 ka BP), late Atlantic (6.5-5.2 ka BP), middle Subboreal (4.5-4 ka BP) and middle Subatlantic (1.8-1.5 ka BP). Fluctuations of relative sea level during the middle and late Holocene were possibly on the order of several meters (from 3 to -2-3 m in the Black Sea and from 5 to -2-3 m in the White Sea). Lower estimates of regressive stages are principally derived from archaeological data on ancient settlements in tectonically submerging deltaic areas and cannot be regarded as reliable.Palaeohydrological analysis does not indicate that intensive (15-25 m or greater) sea level fluctuations were present in the Black Sea or in the White Sea during the middle and late Holocene. Instead, such analysis provides independent evidence to support the argument that significant differences in water level between the Black Sea and the Mediterranean could not be maintained for an extended period of time

Hierarchical analysis of switchgrass morphology, 2005, Boe A, Casler Md,
Switchgrass (Panicum virgatum L.) has potential as a biomass crop in North America. Our objective was to determine effects of cultivar and location on morphological traits that influence biomass in switchgrass. Six cultivars with origins from 37 degrees N, 88 degrees W (Cave-In-Rock and Shawnee) to 46 degrees N, 100 degrees W (Dacotah) were evaluated in 1-yr-old swards at Bristol and South Shore, SD; in 3-yr-old swards at Brookings, SD, and Arlington, WI; and in 15-yr-old swards at Pierre, SD, for biomass; tillers m(-2); reproductive tiller proportions by count and weight, weight tiller(-1); phytomers tiller(-1); leaf, stem, and inflorescence components of tiller weight; and sheath and stem components of phytomer weight. Biomass production was related to region of cultivar origin [e.g., Shawnee produced two times more than Dacotah (6.2 Mg ha(-1))]. Tiller density was highest for Dacotah (1090 tillers m(-2)) and lowest for Cave-In-Rock (520 tillers m(-2)). Reproductive tiller fractions by count were plastic and higher at Arlington (0.81) than Brookings (0.08). Weights per reproductive tiller ranged from 0.7 g (Dacotah) to 3.4 g (Cave-In-Rock). Phytomers per tiller was not plastic (5.2 for Dacotah to 7.4 for Cave-In-Rock). Internode weight exhibited a basipetal increase and was highly plastic. Cultivars responded similarly to location effects on tillers m(-2), weight tiller', and biomass production. Cultivar differences for biomass production were attributed to variation at tiller (phytomers tiller(-1)) and phytomer (weight phytomer(-1)) levels

Ultraviolet Radiation Sensitivity in Cave Bacteria: Evidence of Adaptation to the Subsurface?, 2008, Snider J. R. , Goin C. , Miller R. V. , Boston P. J. , Northup D. E.

We hypothesize that a reduced capacity to withstand or repair cellular damage from ultraviolet radiation may be present in caveadapted microorganisms that never experience such conditions. However, a small number of previous studies have shown that some subsurface bacteria do not show greater sensitivity to ultraviolet radiation (UVR) than surface bacteria. To estimate UVR sensitivity in cave bacteria, bacterial isolates were collected from Carlsbad Cavern, New Mexico, U.S.A., and percent survival following exposure to various UVC and UVA radiation doses was determined. Cave bacteria from Left Hand Tunnel in Carlsbad Cavern and surface bacteria from soil and rocks above Carlsbad Cavern were grown on low and high nutrient media then exposed to 0, 10,000 and 20,000 μWs/cm2 of UVR in a laboratory biological safety cabinet. Incubations were conducted at 15ºC or 37ºC, in accordance with the isolates’ natural temperature environments. In addition, DNA repair capacity was estimated by exposing the organisms to various doses of UVC radiation and measuring survivability. Gram status and pigmentation also were determined. Results showed that most of the cave isolates were more sensitive to UVR than the surface isolates, but survivability data suggest that cave microbes retain some of their capacity to repair UV-induced DNA damage. Selection appears to have favored bacteria that can survive in this low nutrient environment, while not maintaining (or paying the cost of maintaining) unneeded traits such as UVR resistance. Cave bacteria appear to have maintained DNA repair capacity, most likely because of the need to repair damage to their DNA from other environmental stressors found in caves.


Ultraviolet Radiation Sensitivity in Cave Bacteria: Evidence of Adaptation to the Subsurface?, 2009, Snider J. R. , Goin C. , Miller R. V. , Boston P. J. And Northup D. E.
We hypothesize that a reduced capacity to withstand or repair cellular damage from ultraviolet radiation may be present in caveadapted microorganisms that never experience such conditions. However, a small number of previous studies have shown that some subsurface bacteria do not show greater sensitivity to ultraviolet radiation (UVR) than surface bacteria. To estimate UVR sensitivity in cave bacteria, bacterial isolates were collected from Carlsbad Cavern, New Mexico, U.S.A., and percent survival following exposure to various UVC and UVA radiation doses was determined. Cave bacteria from Left Hand Tunnel in Carlsbad Cavern and surface bacteria from soil and rocks above Carlsbad Cavern were grown on low and high nutrient media then exposed to 0, 10,000 and 20,000 ?Ws/ cm2 of UVR in a laboratory biological safety cabinet. Incubations were conducted at 15C or 37C, in accordance with the isolates natural temperature environments. In addition, DNA repair capacity was estimated by exposing the organisms to various doses of UVC radiation and measuring survivability. Gram status and pigmentation also were determined. Results showed that most of the cave isolates were more sensitive to UVR than the surface isolates, but survivability data suggest that cave microbes retain some of their capacity to repair UV-induced DNA damage. Selection appears to have favored bacteria that can survive in this low nutrient environment, while not maintaining (or paying the cost of maintaining) unneeded traits such as UVR resistance. Cave bacteria appear to have maintained DNA repair capacity, most likely because of the need to repair damage to their DNA from other environmental stressors found in caves.

SEISMIC-SAG STRUCTURAL SYSTEMS IN TERTIARY CARBONATE ROCKS BENEATH SOUTHEASTERN FLORIDA, USA: EVIDENCE FOR HYPOGENIC SPELEOGENESIS?, 2009, Cunningham K. , Walker C.

High-resolution, multichannel seismic-re?ection data recently acquired mostly in Biscayne Bay, southeastern Florida, exhibit disturbances in parallel seismic re?ections that correspond to the carbonate rocks of the Floridan aquifer system and lower part of the overlying intermediate con?ning unit. These disruptions in seismic re?ections are indicative of structural characteristics in carbonate rocks of Eocene to middle Miocene age that are interpreted to be related to collapsed paleocaves or collapsed paleocave systems, and include (1) fractures; (2) faults; (3) narrow (hundreds-of-m- scale wide) seismic-sag structural systems; and (4) broad (km-scale wide) seismic-sag structural systems. Commonly, the seismic-sag structural systems are multistoried, re?ecting a vertical arrangement of cyclic zones of structural sags that exhibit a progressive evolution from cave formation; cave collapse; suprastratal sag; and in some cases, ?nal in?ll of the upward termination of sag zones. In the study area, these structural systems are buried by upper Miocene-to-Holocene sedimentary rocks and sediments; however, they may manifest as well-documented, hundreds-of-m-scale wide, sinkholes along the submarine surface of the continental margin in the Straits of Florida. The potential link between the seismic sags and submarine sinkholes suggests the sea?oor sinkholes began to form as early as during the Eocene. We will discuss, speleogenic mechanisms dominating the formation of the narrow, seismic-sag structures that include: vadose, water-table, regional mixing zone corrosive, and ?ank-margin processes. Further, three mechanisms are postulated for the speleogenesis of the paleocave systems associated with the broad seismic-sag structural systems: (1) corrosion by an Eocene mixed fresh-saltwater zone associated with a regional groundwater ?ow system beneath the southern part of the paleo-Florida Platform, (2) hypogenic speleogenesis associated with upward groundwater ?ow driven by Kohout convection and dissolution by mixed fresh and saline groundwater, or (3) hypogenic spelogenesis associated with the upward ascension of hydrogen-sul?de-bearing groundwater charged by dissolution and the reduction of calcium sulfates in deeper Eocene or Paleocene rocks. We will contrast and compare our theories on the timing and processes involved in the formation of seismic-sag structural systems with those proposed in the existing literature for the submarine sinkholes on the continental margin in the Straits of Florida, and discuss how the seismic-sag structural systems and submarine sinkholes may be linked. Future marine seismic data acquisition and interpretation is planned to help develop more accurate timing of formation of paleocaves and paleocave systems, their collapse, and structural impact on suprastratal rocks, and more decisive insight into the speleogenic processes that proceed during the evolution of these seismic-sag structural systems within the Florida Platform.


Ultraviolet Radiation Sensitivity in Cave Bacteria: Evidence of Adaptation to the Subsurface?, 2009, Snider J. R. , Goin C. , Miller R. V. , Boston P. J. , Northup D. E.

We hypothesize that a reduced capacity to withstand or repair cellular damage from ultraviolet radiation may be present in caveadapted microorganisms that never experience such conditions. However, a small number of previous studies have shown that some subsurface bacteria do not show greater sensitivity to ultraviolet radiation (UVR) than surface bacteria. To estimate UVR sensitivity in cave bacteria, bacterial isolates were collected from Carlsbad Cavern, New Mexico, U.S.A., and percent survival following exposure to various UVC and UVA radiation doses was determined. Cave bacteria from Left Hand Tunnel in Carlsbad Cavern and surface bacteria from soil and rocks above Carlsbad Cavern were grown on low and high nutrient media then exposed to 0, 10,000 and 20,000 μWs/cm2 of UVR in a laboratory biological safety cabinet. Incubations were conducted at 15ºC or 37ºC, in accordance with the isolates’ natural temperature environments. In addition, DNA repair capacity was estimated by exposing the organisms to various doses of UVC radiation and measuring survivability. Gram status and pigmentation also were determined. Results showed that most of the cave isolates were more sensitive to UVR than the surface isolates, but survivability data suggest that cave microbes retain some of their capacity to repair UV-induced DNA damage. Selection appears to have favored bacteria that can survive in this low nutrient environment, while not maintaining (or paying the cost of maintaining) unneeded traits such as UVR resistance. Cave bacteria appear to have maintained DNA repair capacity, most likely because of the need to repair damage to their DNA from other environmental stressors found in caves.


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