News Article | April 17, 2017
Europe’s first cavefish has been discovered by a cave diver in Germany. The pale-coloured loach, shown above, is thought to have diverged from surface fish as glaciers from the last ice age receded some 16,000 to 20,000 years ago. “Our first genetic studies, plus knowledge of the geological history of the region, suggest the cave loach population is amazingly young, certainly not older than 20,000 years,” says Jasminca Behrmann-Godel at the University of Konstanz in Germany, who led the team that analysed the fish. “Despite this short time span, the fish show trademark adaptions to cave life compared with loaches from surface locations nearby, including a pale body colouration, much smaller eyes, plus larger nostrils and barbels.” It shows that adaptation to these subterranean habitats can be fast, and just a few thousand years might be enough for a fish to adapt to cave life, says Behrmann-Godel. “Cavefish could exist virtually everywhere in principle, and there’s no good reason to expect long evolution times for them to adapt to cave environments,” she says. Simply dubbed “cave loach” or “barbatula” for now, the fish was discovered in 2015 by Joachim Kreiselmaier, an amateur cave diver. He was exploring a hard-to-reach water-filled cave labyrinth called the Danube-Aach System in southern Germany, which ultimately empties into the River Rhine. Kreiselmaier is a friend of Behrmann-Godel and sent her film and photographs of the strange fish he spotted. Kreiselmaier says the section inhabited by the fish is notoriously difficult to reach, accessible only in dry spells when the underground river is sufficiently calm and clear to allow exploration. “To reach the area with the fish takes an hour, and involves periods of decompression that make the round trip as long as 3 hours,” he says. So far, Kreiselmaier has brought back five live specimens for Behrmann-Godel to examine. “Through comparison of their appearance and genetics with surface fish caught upstream and downstream from the cave, we found evidence that the first European cavefish population is indeed a distinct lineage, with its own adaptations,” she says. Moreover, knowledge of local geology enabled the birth of the new lineage to be dated. The cave system had been sealed for hundreds of thousands of years, but an opening called the Aach spring made it accessible when Alpine glaciers retreated northward around 16,000 to 20,000 years ago. This allowed surface loaches to enter the system for the first time, and they have followed their own evolutionary trajectory since. The cavefish’s eyes are about 10 per cent smaller than those of surface loaches, and their barbels are longer. They also lack scales. Most obviously, they have lost the dark brown blotches typical of surface loaches. “The barbels are enlarged in what seems to be a possible adaption to tactile sensing in the dark,” says Roi Holzman of Tel Aviv University in Israel, who studies how cavefish navigate. “In other cavefish species, barbels are also equipped with chemosensors to help them identify food in sediment, so these fish will need to be further studied to figure these mechanisms out.” Most known cavefish are found in North America and China, and until now none had been seen in Europe. “We would always have expected that cavefish should occur in the cave hotspots in Europe – there is no real reason why not,” says Jörg Freyhof at the Leibniz-Institute of Freshwater Ecology and Inland Fisheries in Berlin But discovering the cavefish in Germany was a surprise, says Behrmann-Godel, because cave systems are far richer in life further south in the Balkans, where hundreds of subterranean species including weird “baby dragon” salamanders have been discovered – but no cavefish so far. “In Slovenia’s Dinaric karst, there are no true cavefish, just surface species that occasionally make it down,” says Janez Mulec of the Karst Research Institute in Postojna, Slovenia. “With the German cavefish discovery, our understanding of underground ecosystems is becoming more complex, indicating that there are often enough nutrients to sustain complex food chains.” Holzman adds that knowledge of the source and speed of evolution is unusual and invaluable. “It opens a window to see evolution in its relatively early stages, which is not common,” he says. Read more: Hunt is on for world’s deepest caves more than 2km underground; Meet the weird amphibian that rules the underworld
Mulec J.,Karst Research Institute |
Vaupotic J.,Jozef Stefan Institute |
Walochnik J.,Medical University of Vienna
Microbial Ecology | Year: 2012
Bioaerosols in cave air can serve as natural tracers and, together with physical parameters, give a detailed view of conditions in the cave atmosphere and responses to climatic changes. Airborne microbes in the Postojna Cave system indicated very dynamic atmospheric conditions, especially in the transitory seasonal periods between winter and summer. Physical parameters of cave atmosphere explained the highest variance in structure of microbial community in the winter and in the summer. The airborne microbial community is composed of different microbial groups with generally low abundances. At sites with elevated organic input, occasional high concentrations of bacteria and fungi can be expected of up to 1,000 colony-forming units/m3 per individual group. The most abundant group of airborne amoebozoans were the mycetozoans. Along with movements of air masses, airborne algae also travel deep underground. In a cave passage with elevated radon concentration (up to 60 kBq/m3) airborne biota were less abundant; however, the concentration of DNA in the air was comparable to that in other parts of the cave. Due to seasonal natural air inflow, high concentrations of biological and inanimate particles are introduced underground. Sedimentation of airborne allochthonous material might represent an important and continuous source of organic material for cave fauna. © 2012 Springer Science+Business Media, LLC.
News Article | September 13, 2016
Donald Trump, Hillary Clinton, and Jill Stein all answered promptly and in some detail, Gary Johnson, the Libertarian, did not. Along with its partners in this effort -- a coalition of 56 leading U.S. science, medicine and engineering organizations representing more than 10 million people -- ScienceDebate.org not only calls on U.S. presidential candidates to address the 20 questions, but also encourages journalists, debate moderators and voters to press the candidates on them. "These 2- issues have at least as profound an impact on voters' lives as those more frequently covered by journalists, including candidates' views on economic policy, foreign policy, and faith and values," said ScienceDebate.org chair Shawn Otto. This view is supported by a 2015 national poll commissioned by ScienceDebate.org and Research!America which revealed that a large majority of Americans (87 percent) want candidates for President and Congress to have a basic understanding of the science informing public policy. The consortium crowd-sourced and refined hundreds of suggestions, then submitted the questions to the four campaigns along with an invitation to the candidates to discuss them on television, preferably in a live science debate (or forum) organized by the group. "Ideally, the people seeking to govern a first-world country would have a basic understanding of everything from sustainable energy to environmental threats to evidence-based medicine," observed the Des Moines Register in a recent editorial. "They would talk about these things... Imagine if the public -- and debate moderators -- pressured presidential candidates to talk about the country's electrical grid or emerging disease threats instead of abortion and transgender bathrooms. Political discourse would be smarter. And the individuals who seek the highest office in the land might learn a few things, too." The list of organizations supporting the 20 Questions project (see below) is a Who's Who of the American science enterprise. To support ScienceDebate's effort to raise awareness of the vital role science plays in modern life, visit ScienceDebate.org. Other supporters and signatories include over 20 Nobel prizewinners, major actors, university presidents, tech leaders, hospitals and hospital leaders, journalists, science activists, and dozens of other science, health, medicine, and engineering advocates from across the nation. **ScienceDebate.org *American Association for the Advancement of Science American Association of Geographers *American Chemical Society American Fisheries Society American Geophysical Union *American Geosciences Institute *American Institute of Biological Sciences American Institute of Professional Geologists American Rock Mechanics Association American Society for Engineering Education American Society of Agronomy American Society of Ichthyologists and Herpetologists American Society of Mammalogists American Institute for Medical and Biological Engineering Association for Women Geoscientists Association of Ecosystem Research Centers Automation Federation *Biophysical Society Botanical Society of America Carnegie Institution for Science Conservation Lands Foundation Crop Science Society of America Duke University Ecological Society of America Geological Society of America *IEEE-USA International Committee Monitoring Assisted Reproductive Technologies Materials Research Society NACE International, The Worldwide Corrosion Authority *National Academy of Engineering *National Academy of Medicine *National Academy of Sciences National Cave and Karst Research Institute *National Center for Science Education National Ground Water Association Natural Science Collections Alliance Northeastern University Organization of Biological Field Stations Paleontological Society *Research!America Scientific American magazine Seismological Society of America *Sigma Xi, The Scientific Research Society Society for Science & the Public Society for the Preservation of Natural History Collections Society of Fire Protection Engineers Society of Wetland Scientists Society of Women Engineers Soil Science Society of America SUNY College of Environmental Science and Forestry Tufts University *Union of Concerned Scientists University City Science Center *U.S. Council on Competitiveness The Wildlife Society World Endometriosis Research Foundation America *Supplied experts to the questions development process **Lead organizer The consortium's list of 20 questions are available online at ScienceDebate.org/20answers.
Kovacic G.,University of Primorska |
Ravbar N.,Karst Research Institute
Science of the Total Environment | Year: 2013
A comprehensive analysis of the increased pressure on karst landscapes due to expansive economic and urban development is presented with the aim of evaluating changes in land use and their deleterious effects on karst relief forms. The study focuses on two areas surrounding the relatively quickly growing settlements of Hrpelje-Kozina and Divača on the Kras plateau (Slovenia) that have been subjected to intensive urban and business development and traffic since the motorway was brought to their vicinity fifteen years ago. National legislation loopholes and technological improvement were the cause of the commonly unsupervised human encroachment which caused the widespread degradation of the landscape. By comparing different topographical and ortophotographical materials from the past four decades and by detailed field inspection of land use and environmental changes, as well as the morphometrical characterization of dolines, the following results have been found: due to the population growth in the past four decades (39% and 50%, respectively), an increase of settlement area by 18 and 11 percentage points took place. Consequently, between 25 and 27% of dolines have disappeared or have been extensively modified (filled up and leveled). According to the local spatial plans, an additional 18% to 28% dolines are endangered. Broad human induced changes in the karst landscape have resulted in a noticeable increase in landscape deterioration, which is consistent with similar phenomena observed in other regions. Due to the extreme susceptibility of the karst to human activities that may lead to the degradation of its exceptional esthetic and environmental value, the alteration of karst processes such as corrosion, endangering of unique habitats and the quality of non-renewable natural resources, it is necessary to promptly define measures for its protection at the national level. © 2013 Elsevier B.V.
Impact of chlorides, nitrates, sulfates and phosphates on increased limestone dissolution in the karst vadose zone (Postojna Cave, Slovenia) [Vpliv kloridov, nitratov, sulfatov in fosfatov na povečano raztapljanje apnenca v vadozni coni krasa (Postojnska jama, Slovenija)]
Kogovsek J.,Karst Research Institute
Acta Carsologica | Year: 2011
Distinctive karst hydrology arises from a combination of high carbonate rock solubility and well developed secondary porosity (fissures). Soil CO2 is the most important influence on solubility of carbonate rock (Ford & Williams 2007). Human activity on the karst surface results in pollution that has an important influence on water quality. Degradation of organic pollution (e.g. waste water, leachates from landfill sites) results in inorganic acids too. These acids could have an important additional influence on dissolution of carbonate rocks in the vadose zone. In the framework of more than 20 years of research on precipitation percolation and transfer of contaminants (direct outflow of waste water from a small military facility where about twenty troops were stationed) through the 100-m thick vadose zone of Postojna Cave, contaminated water was observed in drips and trickles in the cave (up to 60 mg Cl-/l, up to 180 mg NO3-/l, up to 2.8 mg PO34-/l, and up to 50 mg SO42-/l). At the same time the sum of calcium and magnesium (Ca+Mg) of trickles was up to two times larger than the Ca+Mg of either the uncontaminated reference trickle or the input waste water. The amount of dissolved limestone carried by waste water to trickles and drips in the cave was directly proportional to the concentration of contaminant anions present. This demonstrates that there is an accelerated widening of fissures below source points of wastewater. Water with contaminants can penetrate faster and deeper into the vadose zone along the increasingly permeable fissures without losing its dissolving power, and thus significant dissolution occurs ever deeper in the vadose zone. This results in ever faster penetration of contaminants through the vadose zone. In the final phase of such development, which takes many decades or longer, relatively rapid transfer of contaminants through the aquifer all the way to karst springs with minimal self-cleansing effects can be expected.
Sebela S.,Karst Research Institute |
Turk J.,Karst Research Institute
Theoretical and Applied Climatology | Year: 2011
In Postojna Cave, air temperature and pressure monitoring has been conducted since July 21, 2008. Air pressure in the cave at three monitoring sites fluctuates synchronically with outside air pressure. Temperature data for Postojna 1 and 3 show good correlation with outside climate conditions for the period 2009-2010. The temperature at Postojna 1 was increasing constantly from March to May 2009, while at Postojna 2, it was decreasing. Postojna 1 has a seasonal trend in accordance with outer trend, while seasonal trend at Postojna 2 is just contrary to outside trend. Microclimate studies at Postojna 2 show local variability, especially in winter, and exhibit special microclimate conditions that may be due to ventilation of unknown passages in the back. © 2011 Springer-Verlag.
Mulec J.,Karst Research Institute
Journal for Nature Conservation | Year: 2014
Underground tourist cultural and natural heritage sites in Slovenia that share similar management problems with other such sites worldwide include Postojna Cave with more than a half million annual visitors and the UNESCO World Heritage Site Škocjan Caves. The underground environment is challenged by ultrasonic noise derived from different electric devices in a broad range (10-123kHz) that can be minimised with protective housings. Lamps which increase temperature and lower relative humidity should be omitted. Chlorella vulgaris thrived very well under a halogen lamp and LEDs whose spectra were modified to give a natural appearance to illuminated features and emitted photon quanta close to the photosynthetic compensation point (~20μmolphotons/m2s). Remediation of insensitive calcite surfaces colonised by lampenflora with a 15% (v/v) solution of hydrogen peroxide (pH 7.0-7.5) was successful. Because visitors introduce and spread, especially by footprints, many live microorganisms (>10000 colony-forming units per 100cm2), measures to reduce such input should be implemented. Bacterial counts expressed as colony-forming units per m3 were more indicative for the presence/absence of tourists than were changes in carbon dioxide concentration. Not only tourists, but also external climatic conditions influenced the concentration of airborne bacteria. Microbiological parameters should be included in estimating tourist carrying capacity for sensitive underground sites. © 2013 Elsevier GmbH.
Kogovsek J.,Karst Research Institute |
Petric M.,Karst Research Institute
Environmental Earth Sciences | Year: 2013
Karst aquifers are very vulnerable to various pollution sources. Among these, landfills can contribute contaminants over long periods. Groundwater quality monitoring is required to assess the impact of a landfill leachate on underlying aquifer water or spring discharge. Tracer tests are useful for selecting the location and frequency of sampling. Three landfill sites in karst areas were studied with tracer tests. Additional insight was accomplished by the comparison of the tracer transfer and the breakthrough curves obtained from these tests with the results of two other tracer tests carried out in the same period in karst areas without a landfill. To explain the differences observed, the hypothesis of increased permeability below the landfill due to the presence of inorganic acids in leachates was further tested. The results of detailed, long-term monitoring of contaminated drip water in the Postojna Cave were used to verify the hypothesis. The analysis of the simultaneously increased content of calcium, magnesium, and contaminants in the drip water indicates a direct correlation between limestone dissolution and contaminants. Increased dissolution increases secondary porosity and thus permeability of the vadose zone resulting in higher vulnerability of underlying aquifers and springs in the vicinity landfills. © 2012 Springer-Verlag Berlin Heidelberg.
Pipan T.,Karst Research Institute |
Culver D.C.,American University of Washington
Biological Journal of the Linnean Society | Year: 2012
The dominant neo-Darwinian paradigm of the evolution of cave animals is that the severe aphotic, low food environment with little environmental cyclicity imposes strong selective pressures leading to a convergent (troglomorphic) morphology of reduced pigment and eyes, and elaborated extra-optic sensory structures. Challenges to the paradigm come from two fronts. First, troglomorphic animals occur in many aphotic habitats with relatively abundant food and environmental cyclicity. Second, many permanent reproducing populations in caves are not troglomorphic. A review of data on patterns of troglomorphy confirms both of these points. This suggests that the absence of light, rather than resource level and environmental cyclicity, is the important selective factor, and that other forces are at work, including competition and differences in the age of lineages in subterranean environments. © 2012 The Linnean Society of London.
Ravbar N.,Karst Research Institute
Acta Carsologica | Year: 2013
Significance of hydrological variability in karst is presented, which also discusses factors inducing such variability and consequences it may cause. Groundwater flow in karst aquifers is often characterized by strong variability of flow dynamics in response to different hydrologic conditions within a short time period. Consequently, water table fluctuations are often in the order of tens of meters, differences in flow velocities between low- and high-flow conditions can reach ten or even more times. In dependence to respective hydrologic conditions groundwater flow also results in variations of flow directions, and thus in contribution of deferent parts of the aquifer to a particular spring. Te described hydrological variability has many implications for contaminant transport, groundwater availability and vulnerability. Groundwater level rising reduces thickness of the unsaturated zone and decreases protective-ness of the overlying layers. Higher water flow velocities reduce underground retention. Due to more turbulent flow, transport and remobilization of solute and insoluble matter is more effective. During high-flow conditions there is usually more surface flow and hence more concentrated infiltrations underground. Particularly in karst systems that show very high hydrologic variability, this should be considered to correctly characterize, understand or predict the aquifers' hydrological behaviour and to prepare proper protection strategies.