Etude de la phase gazeuse occluse dans les laves de «l’Ardoukôba», volcan éphémère d’une dorsale émergée (Afar)     

J. L. Zimmermann  J. L. Cheminee  M. Chaigneau 《Bulletin of Volcanology》1981,44(3):527-546

Gases trapped in lavas of three main flows of the Ardoukôba eruption (8 to 15 November, 1978) have been analysed by mass spectrometry. These analyses concern both plagioclase phenocrysts and microcrystalline mesostasis. Fluids are released between 500°C and 1200°C, and consist of H₂O, CO₂, CO, N₂, SO₂, HCl, H₂, CH₄ with traces of hydrocarbons and H₂S. The total content is less than 0.3–0.4 wt. % of samples with about 0.1–0.15 wt % of H₂O. No significant variation among the three flows is observed. Plagioclase phenocrysts are less abundant in fluids than the mesostasis (～2/3). The gases trapped in these phenocrysts are richer in CO and organic compounds, whereas mesostasis contain more H₂O, CO₂ and SO₂. CO is likely produced by reduction of CO₂ and H₂O with carbon during either analyses or eruption itself, or is of primary origin. In the latter case, gas composition suggests an entrapment temperature of about 1200°C ± 75°C. Kinetic study of the water and carbon dioxide release allows to calculate the diffusion characteristics of these fluids. Water and carbon dioxide behave rather similarly. Plagioclase gives a single activation energy value (8 Kcal/mole), while mesostasis gives two values (8 Kcal/mole, 15 Kcal/mole). Diffusion coefficients at 20°C are estimated to fall in the range 10^?13 · 10^?12 cm² · sec^?1.  相似文献   

Über die Entnahme von Wasserproben in fliessenden Gewässern     

O. Jaag  H. Ambühl  P. Zimmermann 《Aquatic Sciences - Research Across Boundaries》1956,18(1):156-160

Ohne Zusammenfassung  相似文献   

Zur Methodik der Quantitativen Biologischen Probenahmen in Stark Strömenden Flüssen     

Dr. U. Von Zimmermann  Dr. H. Ambühl 《Aquatic Sciences - Research Across Boundaries》1970,32(1):340-344

Zusammenfassung Es wird eine Technik zur Entnahme quantitativer Organismenproben aus tiefen, schnellfliessenden, steinigen Flüssen beschrieben. Mit Hilfe eines kreisrunden Stechsegmentes wird ein Areal von rund 750 cm² abgegrenzt und dieses sodann mit einem Vakuumschlauch abgesaugt. Das Mundstück des Schlauches wird durch einen Taucher geführt.

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Summary A technique is described for taking quantitative samples of organisms from deep, rapidly flowing rivers with rocky beds. An area of about 750 cm² (0.81 sqft) is confined by a circular sampler, which penetrates the bottom. Organisms in the enclosure are freed from the substrate by hand. Smaller sediment particles, organisms, and water are then pumped out by a vacuum hose. The intake of the vacuum hose is guided by a diver.

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Buchbesprechungen     

Christian Zimmermann  K. Wuhrmann  HR. Bürgi  Peter Perret  K. Klingler 《Aquatic Sciences - Research Across Boundaries》1973,35(1):196-200

Ohne Zusammenfassung  相似文献   

Ökologische und physiologische Untersuchungen an der planktischen BlaualgeOscillatoria rubescens D.C. unter besonderer Berücksichtigung von Licht und Temperatur     

Dr. Ulrich Zimmermann 《Aquatic Sciences - Research Across Boundaries》1969,31(1):1-58

Zusammenfassung Der Vierwaldst?ttersee (Horwer Bucht), Thunersee (H?he Faulensee), Luganersee (Bucht von Lugano) und Mauensee (ein Kleingew?sser im Schweizerischen Mitelland) wurden im Zeitabschnitt 1965 bis 1967 periodisch untersucht. Durch die chemische Analyse wurden die folgenden Komponenten erfasst: Sauerstoff, Nitrat— Stickstoff, Phosphat— Phosphor (PO₄−P), partikul?rer Phosphor (PP), SBV und pH-Wert. Das Phytoplankton wurde im umgekehrten Mikroskop ausgez?hlt, wobei der quantitativen Verteilung vonOscillatoria rubescens D. C. in den verschiedenen Tiefenstufen besondere Beachtung geschenkt wurde. Gleichzeitig wurden Temperatur und subaquatische Ver?nderungen des lichtes gemessen sowie mit der C¹⁴-Methode die Prim?rproduktion bestimmt. In mehr als 80% aller F?lle fielen dieOscillatoria rubescens-Maxima mit jenen Tiefenstufen zusammen, in denen weniger als 14°C gemessen wurde. In diesen Tiefenstufen wurde gleichzeitig in mehr als 65% aller F?lle weniger als 4% der Oberfl?chen-intensit?t des grünen Lichtes (VG 9) beobachtet. Der Einfluss von Licht und Temperatur auf das Wachstum vonOscillatoria rubescens wurde in einem Lichtthermostat experimentell untersucht. Bei temperaturabh?ngigenI _k-Werten zeigte sich, dass sich diese Alge bei einer Lichtintensit?t von 1500 Lux erst im Bereich von 30°C optimal entwickelt. Oberhalb 29°C wirkte sich eine Steigerung über 1500 Lux hinaus wieder hemmend aus. Aus diesen Beobachtungen wurde abgeleitet, dass es sich beiOscillatoria rubescens um eine eurytherme und oligophote Form handelt, und dass das Auftreten vonOscillatoria rubescens-Maxima in der vertikalen Verteilung des Phytoplanktons in einem See durch das Zusammenspiel der beiden Faktoren Licht und Temperatur bedingt wird.

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Summary The Lakes of Lucerne (Horw Bay), Thoune (Faulensee region), Lugano (Lugano Bay) and Lake Mauen, a small lake in central Switzerland, were investigated periodically from 1965 to 1967. The water was analysed in view of determining the following components: oxygen, nitrate-nitrogen, phosphate-phosphorus (PO₄−P), phosphorus incorporated in cell mass (PP), Langlier index. Phytoplankton was counted in an inverted microscope with special consideration to quantitative distribution ofOscillatoria rubescens D. C. at various depths. Temperature and light variations in function of depth were measured simultaneously and the production rate was determined by means of the C-14 method. In over 80% of all cases, theOscillatoria rubescens-maxima coincided with depths showing temperatures under 14°C. In over 65% of all cases, the intensity of green light (VG9) in such depths was less than 4% of the surface intensity. The influence of light and temperature on the growth ofOscillatoria rubescens was tested with a light thermostat. It was shown that maximum growth occurred at temperatures around 30°C and light intensities of 1500 Lux. Increase of light intensities above 1500 Lux had a negative effect on the growth rate at temperatures higher than 29°C. Our investigations lead to the conclusion thatOscillatoria rubescens is a eurythermal, oligophotic species and that the occurrence ofOscillatoria rubescens-maxima in the vertical distribution of the phytoplankton in a lake is caused by the combined effects of light and temperature.

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Production and nutrient dynamics of aSyringodium filiforme Kütz. Seagrass bed in Indian River Lagoon,Florida     

F. T. Short  J. Montgomery  C. F. Zimmermann  C. A. Short 《Estuaries and Coasts》1993,16(2):323-334

A year-long analysis of the characteristics of the seagrassSyringodium filiforme and the associated dynamics of the nutrient pool in the sediment pore water was done to assess co-variation. Changes in seagrass growth rate and standing stock throughout the year were accompanied by seasonal changes in the nutrient pools. The link between plant production and morphometrics and the sediment nutrient pool was found to be predominantly physiological, with the plant balancing the ability to photosynthesize with the nutrients needed for maintaining production. Measurements of whole plant growth for this seagrass, rather than the more typical leaf growth measurements, show that the production of new shoots and rhizome elongation for these plants represents as substantial amount of growth that usually goes unmeasured. Further, these whole plant growth measures demonstrate the rapid lateral rhizome spread of this species, exceeding one meter per plant per year. The primary cause of seasonal variation in the yearly seagrass cycle was investigated. Correlation analysis supported the hypothesis that the major factor controlling seasonal variation in this seagrass was light. During the peak growing season, however, growth was not regulated by light but by nitrogen. Depletion of the sediment ammonium pool and reduction in pore water ammonium relative to adsorbed ammonium, as well as changes in N content of seagrass leaves, support our hypothesis of peak growing season nitrogen limitation. Our results forSyringodium filiforme in terrigenous sediments are in contrast to our recent findings of phosphorus limitation in this same species occurring in carbonate sediments.  相似文献   

Ozone measurements from the Balloon Intercomparison Campaign     

D. Robbins  J. Waters  P. Zimmermann  R. Jarnot  J. Hardy  H. Pickett  S. Pollitt  W. Traub  K. Chance  N. Louisnard  W. Evans  J. Kerr 《Journal of Atmospheric Chemistry》1990,10(2):181-218

Measurements of the Balloon Intercomparison Campaign (BIC), conducted during fall, 1982 (BIC-1) and summer, 1983 (BIC-2), are reported. Results of five remote and two in situ techniques agree (with a few exceptions) within 95% confidence level uncertainties and generally within 15% above 20 km. Weighted mean profiles, which best represent conditions during the capaign, are used as a comparison standard. Accuracies of experiments indicated by BIC generally confirm estimated uncertainites for ECC sondes, UV photometry, and microwave emission experiments, are somewhat better for far IR emission and IR absorption experiments, and are somewhat worse for IR emission and solar UV absorption experiments. The large collection of BIC measurements confirms a problem reported earlier with current theoretical modeling of ozone near 40 km where transport is negligible and the chemistry is believed to be simpler.  相似文献   

Die Petrographie des Knollenmergel,Mittlerer Keuper,Trias     

Prof. Dr. Friedrich Lippmann  Manfred Zimmermann 《International Journal of Earth Sciences》1983,72(3):1105-1133

In Württemberg, the upper part of the Middle Keuper is referred to as “Knollenmergel” (= “nodular marl”, a marly claystone containing carbonate nodules), 24 samples were studied from a test well located near Hechingen. X-ray diffraction was used for the determination of the mineral composition of whole rocks and of the clay fractions. The coarser fractions were studied under the petrographic microscope. The fractions < 2π Ø consist chiefly of an mixed-layer mineral with illite and expandable, montmorillonite-like layers as the components. There are about 30 % of expandable layers. A low-angle reflection near 31 Å is indicative of considerable order among component-layer species approaching that of rectorite. In the lower part of the section, moderate amounts of sudoite are present in addition. Illite as a discrete phase could not be determined with certainty. The microscopic fractions consist partly of monomineralic grains of quarz, dolomite, and calcite. In addition, they contain considerable amounts of polymineralic aggregates, which were not dispersed by the rather mild disintegration method used in the present study. Accordingly, the rocks are claystones characterized by the same degree of lithification as those occurring in other parts of the Keuper in Württemberg. The interstratified mineral is tentatively derived from the erosion of a uniform body of volcanogenic material of Paleozoic age. On the basis of grain-size distribution, the Knollenmergel is a water-laid sediment. Eolian transport as advocated by some geologists can be excluded. The difficulties experienced with the Knollenmergel as a building ground are explained by the high percentage of the expandable interstratified mineral and the dearth of a genuine sand fraction.  相似文献   

A bottom-up methodology for integrating underwater video and acoustic mapping for seafloor substrate classification     

Christopher N. Rooper  Mark Zimmermann 《Continental Shelf Research》2007

A method that links acoustic mapping data to underwater video observations of seafloor substrate is described for use in defining fish habitat. Three study areas in the Aleutian Islands were acoustically mapped using sidescan and multibeam sonar. The sidescan sonar data were used to compute average reflectivity (hardness) and seafloor complexity. The multibeam depth data were used to determine local slope, rugosity (seafloor roughness) and relative height. Underwater video was collected from three to four transects in each of the three study areas. The underwater video was used to classify the seafloor into nine observed primary and secondary substrate classes. A statistical relationship between the observed (video) and the remotely sensed (acoustic) seafloor characteristics was estimated using a classification tree. The best classification tree utilized rugosity, reflectivity and complexity data and produced misclassification rates of less than 25% overall. Mean grain size of sediment samples was not strongly related to the acoustic data. Error rates were highest for those substrate classes with the smallest number of data points. The results highlight the need for adequate sample sizes and coverage of all potential substrate types when groundtruthing acoustic maps.  相似文献   

Sound in media: audio drama and audio-guided tours as stimuli for the creation of place     

Torsten Wissmann  Stefan Zimmermann 《GeoJournal》2015,80(6):803-810

Mass media frequently makes use of more than the visual image. With the exception of music, movie scores, and radio news however, media geographers have largely ignored the impact sound in media has on shaping and characterizing our experience of the world. We address this lack by showcasing two types of audio media: audio drama and audio-guided tours. The former will be explored with the help of the world’s most successful audio drama series The Three Investigators to give a historical and theoretical introduction to the realm of sound within mass media. The latter will be illustrated using the example of the Austin Walking Tour as a representative production for city tourism.  相似文献