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- Brundin, Lars
(författare)
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Chironomiden und andere bodentiere der südschwedischen urgebirgsseen : Ein beitrag zur kenntnis der bodenfaunistischen charakterzüge schwedischer oligotropher seen
- 1949
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Problems. Methods. Material.There are more than 85000 lakes in Sweden, the majority of which belong to the oligotrophic type sensu Naumann, and which present an inexhaustible field for investigation. In view of the varied and complicated nature of the problems and the young age of limnological science it is natural that the knowledge of these lakes in spite of the efforts of many investigators should still be fragmentary. This holds good also of the bottom fauna which in many respects is so important.When, in 1941—1942, I was working on a quantitative material of bottom animals from oligotrophic lakes in Jämtland, North Sweden, this lack of data was strongly felt. There was no solid holding-ground for a comparison with other lakes in Sweden, and many factors indicated that the production of the bottom animals in oligotrophic lakes in Sweden was considerably underestimated, probably because of the methods not being quite satisfactory. Particularly conflicting results had been reached by previous investigators as regards the influence of the humic standard on the bottom fauna, which is a vital problem concerning the Swedish lakes. As regards the chironomids constituting, as is well known, the most important group among the bottom animals in the Swedish lakes, our almost complete lack of knowledge was most deeply felt. It was clear that a real understanding of the relationship between the different laketypes and the profundal fauna could only be obtained by determining the species represented by the chironomid larvae. The very fact that certain lakes in Jämtland that Naumann would undoubtedly have characterized as oligotrophic had a chironomid fauna, which according to the valid typology of the lakes based on the bottom faunistical conditions must be regarded as belonging to the mesotrophic type, was in itself an inducement enough for a closer study of chironomids and their dependence on environmental factors.Thus important problems were waiting for a solution. To contribute to this I started studies of the bottom fauna in 1942 with a particular regard to the chironomids in the Aneboda-Växjö district in the central part of the South-Swedish highland. These studies were concluded in the autumn of 1948.
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- Bergsten, Folke, 1889-
(författare)
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The seiches of Lake Vetter
- 1926
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Ingår i: Geografiska Annaler. - Stockholm : Svenska sällskapet för antropologi och geografi. - 1651-3215.
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)
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- Grip, Erland, 1905-2007
(författare)
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Die Arvidsjaurporphyre : Eine archäische Effusivgesteinsreihe im nördlichen Schweden
- 1935
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Zusammenfassung Das Altersschema der Gesteine im nördlichen Västerbotten und südlichen Norrbotten erhält nach der oben gegebenen Darstellung folgendes Aussehen:Die Sorselegranitreihe mit Gangfazies.Die Vargforsformation (Konglomerate, Grauwacken, saure und basische Effussive).Revsundsgranit.Jörngranit.Svartlågrauwacke.Andesit.Liparit.Quarzkeratophyr, Keratophyr, Dazit.Andesit Schiefer und Quarzit.Basaltischer Andesit. Leptit (saure Effusive und Tuffe).Die Arvidsjaurporphyre schliessen sich in ihren unteren Teilen der Leptitformation des Skelleftefeldes an, indem Andesite mit Schiefern wechsellagern. In den NW-Teilen des Skelleftefeldes werden die Schiefer dünner und gehen in gröbere Sedimente wie Sandstein und Quarzit über. Die Porphyrreihe wird nach oben immer saurer. Im Lavergebiet sind die Zwischenglieder dazitisch, während sie in den Suddesvare- und Däppis-Kaxlidengebieten keratophyrisch sind. Über diesen Gesteinen liegen mächtige und weit verbreitete Liparitdecken. Die Effussivfolge wird von Andesit als »Nachgeburt» abgeschlossen. Tuffe und Tuffagglomerate liegen vielerorts zwischen den Lavadecken, aber im Vergleich mit den Laven spielen sie quantitativ eine sehr kleine Rolle. Der ältere Granit oder Jörngranit ist jünger als die Porphyrreihe und die darauf folgende Svartlågrauwacke. Die ganze Reihe der Arvidsjaurporphyre dürfte eine Effusivfazies des Jörngranits mit allen dessen Differentiaten sein. Jünger als der Jörngranit ist der Revsundsgranit, zu welchem keine Effusivfazies angetroffen worden ist. Nach dem Revsundsgranit kommt eine grosse Diskordanz, auf welche die Vargforsformation mit ihren Sedimenten und Effusiven folgt. Die Vargforsformation ist vom Sorselegranit und dessen Gangfazies durchbrochen, und ihre Effusivgesteine müssen als die Oberflächenfazies des Sorselegranits betrachtet werden.
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- Hjulström, Filip, 1902-1982
(författare)
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Studies of the morphological activity of rivers as illustrated by the River Fyris
- 1935
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- (Summary)The investigation bears upon a determination of the rate of the mechanical and chemical denudation within the Fyris river-basin north of Uppsala in Central Sweden. The introduction deals with the morphological activity of rivers in general and the different methods (the sampling and the plot methods) for the determination of the rate of degradation.In order to state the reason for the method of investigation as well as for the interpretation of the results there is given an account of the dynamics of streams (Ch. I) and some reflections upon the influence of the stream on solid material at the bottom and in suspension (Ch. II). – A short account of the falling of the water calls attention to the tendency of the water to spread out in drops, whereby the erosion is reduced. – The critical velocity for the transition from streamline to turbulent flow (or inversely) has an especially great interest as to the erosion and is the object for some experiments. It is shown that the increase in viscosity by adding silt to the water has almost no signification, compared to that of the temperature. The critical value of Reynolds´ number for flow in thin watersheets above sand, like the run-off of rain-water, is determined. The result is, that the Rcrit. is very low and that, therefore, the rain-wash is caused by water in turbulent motion (p. 233–243). As to the characteristics of turbulence treated at some length here, the pulsations, and their importance in erosion are especially noticed; the variations in the contents of silt in the case of erosion (p. 251–255) as well as without erosion (p. 388) have been examined, partly by means of the Falck meter.Chapter II gives an account of the theories of the influence of the hydrodynamic upthrust and the Austausch-process. The results in meteorology about turbulence are applied to streaming of water in a river. The equilibrium conditions, in regard to the distribution of silt have been examined. An experiment has been carried out in order to determine the Austausch-coefficient at different points of a cross-profile, and shows a very complicated distribution.Chapter III discusses some problems of erosion, transportation and deposition. From old and new investigations a new curve is drawn, showing the relation between grain-size and erosion velocity. In a section about erosion of solid rocks an attempt is made to show that besides evorsion and direct wearing by silt-laden water another, hitherto unobserved mode of erosion may exist, namely by cavitation-erosion. The agreement in appearance between the »Sichelwanne», described by Ljungner and the forms, caused by cavitation-erosion is pointed out. This mode of erosion may, in all probability, mainly have some affect below great ice-sheets with great hydrostatic pressure and in water-falls, where the velocity of the water is great. – The problem of transportation of different materials over a bed, consisting of a finer size of particles has been examined. The conclusion is, that only for a bed, consisting of special groups of material transportation of some material without erosion may exist. The stratigraphical significance of this conclusion is pointed out (p. 323–327). As to the transportation of bedload the problem of stability is applied to the motion of the bottom-layer. It is seen that the possibility of the occurrence of a bottom-layer with laminary motion is greatest in the case of erosion. The attempts to find a method for determining the amount of transportation of the bed-load brought about an examination of the mode of transportation along the bottom. The origin of the dune mode of traction is by laboratory-studies shown to be connected with the occurrence of pulsations. As to the wave-length it will be seen that there is a certain accordance with the results of research in the stability-problem, though these are not valid for streaming near a boundary. The presence of stream ripples in an unchanged form signifies equilibrium without erosion or deposition. The transportation of the sand as a uniform layer generally signifies erosion. – A short section deals with the capacity of a stream; it is suggested that a river with access to material of all grain-dimensions and the velocity necessary to erode them has no maximum-load of material transported. Hovever, a stream which transports rolling matter without access to anything else can only transport a certain amount of this matter.Chapter IV deals with the degradation of the Fyris river-basin. A summary of previous investigations in connection with the geographical, geological, climatological and hydrological conditions is given. An especially aggrevating circumstance for the present investigation was offered by the damming up of the Fyris-water by the Mälar lake; the rating-curve for the Uppsala Nedre gauge station is not reliable for low water-levels. The error caused by this circumstance, in the total sum of the material transported from the area concerned, however, only amounts to a few per cent. The method of investigation has demanded especially great care, as the material has a very fine grain-size, and partly consists of colloids. Different methods of procuring the samples are critically discussed. A practical method of analysis is worked out, based upon adsorption by asbestos.For five years (July 1929–June 1934) analyses of water-samples have been carried out. It is seen that the River Fyris, on an average, each year carries away from the drainage-area north of Uppsala sedimentary matter to an amount of more than 5500 tons per year and dissolved matter to about 62000 tons, or together 57370 tons. Per sq.-km. this forms 56.1 tons per year. The variations in the contents of silt are put in relation to several, mainly climatological, factors. The erosion is mainly interfluvial, and caused by rain-wash. The spring flood at the melting of the cover of snow transports the greatest load of sedimentary matter but also the autumn rains cause transportation of large masses. The two other periods, the cold and the warm, have no great transportation. The mechanical and the chemical composition of the material have been examined.
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