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A new hyporheic Bogidiella (Crustacea, Amphipoda) from Mallorca |
| Autor/es | Petrus, Joan L. ; Stock, Jan H. |
| Matèries en català: | Biologia. |
| Matèries en anglès: | Biology. |
| Resum-Abstract: | [spa] Se da a conocer la primera cita de Eurygeophilus multistiliger (Verhoeff, 1899) para las Islas Baleares, localizada en la Cova de sa Cometa des Morts (Escorca, Mallorca) en la Serra de Tramuntana. También se exponen ciertas variaciones observadas en el segundo ejemplar macho conocido de la especie, de los ejemplares holotipos y sintipos de la especie. [eng] From 1980 on, I began to discover that certain dripstones (mainly stalagmites) in karstic cave systems in Hungary were exhibiting re-dissolution phenomena which had not been visible in the caves 5-10 years previously. These deformations unquestionably arise from the corrosional effects of karst-waters permeating onto the dripstones. With a view to clarifying the causes of this effect, my colleagues and I commenced researches in situ not only in Hungary, but also in caves in Czechoslovakia, Rumania, Bulgaria, Yugoslavia and Austria. We established that the spreading of the phenomenon is universal throughout Central Europe, though to different extent in caves with different natural features. Signs of the recent dripstone degradation syndrome: sharp, jagged-edged, irregular-shaped craters; ((calderas)) with undermined sides; sharp-edged, basin-like drainage trenches; areal dripstone surface re-dissolution in the splash-spray zone of the water drops falling from the heights; in certain cases almost total dripstone dissolution; often, the subsequent softening of the material of the dripstones, which become cream-like. My investigations to date indicate that, the thicker the bioactive and permeable soil layer cove- ring the karst rock, and the deeper the roots of the macrovegetation (deciduous trees) growing in this soil, the more frequent or the more extensive the new type of dripstone re-dissolution. On the basis of the available data, it seems probable that pine woods play a somewhat different role in this correlation system from the role of deciduous woods, e.g. oak, beech, hornbeam, etc. A certain degree of inverse proportionality can be documented between the frequency of occurrence of the dripstone degradation syndrome and the depth of the cave zone in question beneath the surface. The smaller the depth of a cave system beneath the surface, the more likely the occurrence of this new type of dripstone degradation in it. I subsequently made a wide-ranging analysis of how the observed degradation syndrome is correlated with the pH of the karst soil and with the microbiological and soil-composition parameters. The trends in the chemical changes of the karst-waters entering the caves were documented. It turned out that, compared to the water analysis data from 1929, which were used as referent basis, there had been an increase of 400-600 % in the sulphate content of the karst-water dripping in at the same points of the caves; smaller increases were also observed in the nitrate and chloride contents. In those caves and on those dripstones where the dripstone re-dissolution was particularly extensive, the sulphate content of the karst-water was higher than average. My researches therefore suggested the result that the recent dripstone degradation may be induced either by the recent strong increase in the sulphate concentration of the karst-waters, or indirectly by one or other of the factors responsible for the increase in the sulphate content. |
| Font: | Endins 1990, Vol. 16, pp. 47-51 |
| Identificador: | e-ISSN: 2386-7299 |
| Tipus de document: | info:eu-repo/semantics/article ; info:eu-repo/semantics/publishedVersion |
| Avís legal: | all rights reserved ; info:eu-repo/semantics/openAccess |