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Meta menardi and M. bourneti are two species of spiders inhabiting caves and other subterranean habitats. The occurrence of both species within the same cave has never been proved convincingly and several authors hypothesized a complete niche differentiation mainly based on microclimatic conditions.In order to study the apparent niche differentiation of the two species, we studied several populations of M. menardi and M. bourneti occurring in six caves in the Western Italian Alps (NW Italy). A series of squared plots were monitored monthly from March 2012 to February 2013. At each survey, we counted individuals and we collected the main environmental variables at each plot, namely distance from cave entrance, structural typology (wall, floor or ceiling), light intensity, wind speed and counts of potential prey. Moreover, temperature and relative humidity were continuously logged in each cave. We run several statistical models (GLMMs) in order to relate the counts of individuals to the environmental parameters. The distance from the cave entrance, structural typology and prey availability resulted most important factors driving the abundance of both species within the cave. On the other hand, despite life cycles appeared very similar, the two species seems to exhibit different tolerance to the microclimatic variations within the cave, which emerged as the main factors determining the differentiation of their niche. At least in our study area, M. bourneti tolerates broad microclimatic fluctuations and is potentially able to colonize a wide variety of caves. On the other hand, when the climatic conditions in a cave are suitable for M. menardi (narrow ranges of relatively low temperature and high humidity), M. bourneti is excluded.
Hermeneutics is the theory of interpretation. One of its major components is recognizing prejudgments, or forestructures, that we bring to our objects of study. In this paper, we construct a historical narrative of the evolution of thinking about the role of caves in relation to groundwater flow in limestone, and we tabulate forestructures as they appear in the story. This account consists of three overlapping time periods: the before and after of an incident that repelled hydrogeologists and students of karst from each other in the middle of the 20th century; a period, up to around the turn of this century, when karst science and mainstream hydrogeology were on different tracks; and a period of convergence, now intertwining, beginning roughly in the last quarter of the 20th century. Two influential players in our story are M.K. Hubbert, whose introduction of the Eulerian perspective of flow was a force for divergence, and R.M. Garrels, whose founding of the field of sedimentary geochemistry was a force for convergence. Other key players include F.T. Mackenzie, J.E. Mylroie, V.T. Stringfield, the U.S. Geological Survey, the Bermuda Biological Station, and the Gerace Research Center in the Bahamas, along with the historical accounts of W.B. White. Our narrative ends with the broader acceptance of the concept of multiple-permeability karst aquifers. We flag in our construction a total of 43 forestructures distributed amongst the categories of hermeneutic theory: 14 in the category of preconceptions; 9 in goals; 14 in tools such as skills; and 6 in tools such as institutions. These counts are an example of the concept of social construction of statistics, and we discuss the implications in terms of the huge number of potential combinations of forestructures that could shape alternative historical narratives of this subject over this time frame.
23rd International Karstological School "Classical Karst", Postojna, June 15th to 21st 2015
Caves - exploration and studies combined with the 50th anniversary of the International Union of Speleology - UIS : program & excursions & UIS & abstracts
Several caves of hydrothermal origin in crystalline limestones and metasomatic silicites were investigated in the central zone of the Štiavnica stratovolcano, Štiavnické vrchy Mountains, central Slovakia. Evidence of hydrothermal origin includes irregular spherical cave morphology sculptured by ascending thermal water, occurrence of large calcite crystals and hydrothermal alteration of host rocks, including hydrothermal clays. The early phases of speleogenesis in the crystalline limestone near Sklené Teplice Spa were caused by post-magmatic dissolution linked either to the emplacement of subvolcanic granodiorite intrusions during Late Badenian time or to the spatially associated Late Sarmatian epithermal system. Speleogenesis in metasomatic silicites in the Šobov area is related to hydrothermal processes associated with the pre-caldera stage of the Štiavnica stratovolcano in Late Badenian. Both localities are remarkable examples of hydrothermal speleogenesis associated with Miocene volcanic and magmatic activity in the Western Carpathians
We review the current understanding of the physics of caves and karst. Our review focuses on research that has used simple physically based models to improve understanding of processes that occur in karst. The topics we cover include cave atmosphere dynamics, transport within karst conduits, and models of speleogenesis and related processes. We highlight recent advances in these subjects and attempt to identify promising areas for future work. In our judgment, many of the most intriguing open questions relate to the interactions between these three groups of processes.
The aim of this study is to characterize in detail, the mineralogy of different-shaped concretions as well as to investigate the physico-chemical parameters of the associated mine drainage and drip waters in the Santa Barbara level of the Libiola Mine (NW Italy) by several geochemical and mineralogical techniques. Under the term “minothems” we are grouping all those secondary minerals that occur under certain form or shape related to the conditions under which they formed but occur in a mine, or in any artificial underground environment (i.e., "mine speleothems"). Different types of minothems (soda straw stalactites, stalactites, and draperies) were sampled and analyzed. Mineralogical results showed that all the samples of stalactites, stalagmite and draperies are characterized by poorly crystalline goethite. There are significant differences either in their texture and chemistry. Stalactites are enriched in Zn, Cd, and Co in respect to other minothems and show botryoidal textures; some of these exhibit a concentric layering marked by the alternation of botryoidal and fibrous-radiating textures; the draperies are enriched in V and show aggregates of sub-spheroidal goethite forming compact mosaic textures. Geochemical investigations show that the composition and physico-chemical parameters of mine drainage and drip waters are different from the other acidic mine water occurrences in different areas of the Libiola Mine, where minothems are less abundant. All mine water samples contain Cu, Ni, and Zn in appreciable levels, and the physico-chemical conditions are consistent with the stability of ferrihydrite, which however tends to transform into goethite upon ageing.
This article deals with speleology applied to the exploration of a siphon named “Combe du Creux”. It is located in France, in the department of the Doubs. We present surveys and the specific forms that are encountered in this flooded cave; eventually we propose a possible evolution of this sump. Cave diving, regarded as cave science, closely associated to underwater photography, is a good mean to investigate such a cave.
We have been diving in this sump since 2003 and we present the results of 13 years of explorations, up to July 2016.
After having explored this cave up to the farthest known point, we made a survey (elevation and plane view). Further dives, using a rebreather when necessary, enabled a work of observation and underwater photography.
We observed concretions – limestone as well as clay – and potholes below the current water level. We also observed ribs and scallops. The underground development of the cave seems well correlated with geologic elements that can be observed outside.
The set of all the observations leads to the conclusion that, at long time scale, the water level has fluctuated. It has been, at least once, 46 m (151 ft) below its current position. In one place inside the cave, it has been observed interactions between flutes and scallops: this new information should be taken in account in any new theoretical or computational modeling of scallops.
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