The control of the production process of phytoplankton by the physical structure of the aquatic environment with special reference to its optical properties

This tutorial was designed for nonbiologists requiring an introduction to the nature and general timescales of phytoplankton responses to physical forcing in aquatic environments. As such, an effort was made to highlight biological markers which might assist in identifying, measuring and/or validating physical processes controlling the variability in the distribution, abundance, composition and activity of phytoplankton communities. Given the recent advances in environmental optics and remote sensing capabilities, a special emphasis was placed on the nature and utility of phytoplankton optical properties in current bio-optical modelling efforts to predict temporal and spatial variability in phytoplankton productivity and growth.     

A lithogeochemical approach to Stratigraphical problems at the Millstream potash deposit, New Brunswick, Canada

A lithogeochemical study was undertaken of the Millstream potash deposit, New Brunswick, Canada, a marine evaporite deposit with a complex depositional and tectonic history. The objective of the study was to determine if potash intersections in boreholes represent different geological horizons, or the same stratum repeated by folding or faulting. The deposit is found at a depth of 800–1000 m.Water-soluble and -insoluble fractions of drill core from five ore zones in four holes were analyzed using multielement ICP instrumentation following sequential hot water and aqua regia leaches. Meaningful variations in the data for the different ore zones were evident for eight elements in the water-soluble portion, and for seventeen elements in the water-insoluble residue. These results characterize a lowermost sylvinite unit which is relatively depleted in most elements, with the exception of Mg and Al in the residue. Regression analysis indicates a weak correlation between Fe and the common base metals, in contrast to the immediately overlying sylvinite unit which is relatively enriched in most elements, including Fe, but where Fe apparently exerts no control over the base metals. Cluster analysis confirms these two units are easily distinguished from each other. The upper two ore horizons are distinguishable from the lower units on the basis of different abundances of some elements, such as water-soluble B, and on the strong scavenging abilities of Fe on the common base metals.No single element is able to uniquely fingerprint a particular sylvinite horizon, but suites of elements are able to classify each horizon as geochemically distinctive. The results appear to confirm the validity of the geological correlations.     

The Southern part of the Armorican orogeny: A result of crustal shortening related to reactivation of a pre-Hercynian mafic belt during Carboniferous time

This synthesis of detailed geological and geophysical information relates deep crustal structure to deformation and the emplacement of granites in the South Armorican Massif and the adjacent continental shelf. Near the continental margin a zone of geophysical anomalies is regarded as a nearly complete line of suture between a southern continent and America. A major mafic body in the trace of the supposed suture in interpreted as a relic of probable oceanic crust which has apparently acted as a deflector of regional strain.It is proposed that late in the Hercynian collision history, during late Carboniferous time, compressional strain acted across the mafic body and can be directly related to generation of younger regional structures in the metasediments and to localization of granite emplacement.     

Crustal transit time monitoring using PKP

The arrival time difference for the AB branch of PKP from deep Tonga earthquakes is constant over years with a standard deviation of ±0.05 seconds at seismographs located 10 to 50 km from each other. If published travel time curves are used to calculate the relative residuals of PKP the standard deviation from the constant mean is improved by approximately 0.01 seconds for AB branch data. For the BC branch, standard deviations of relative travel times of ±0.06 seconds are reduced to less than ±0.05 seconds by calculating relative residuals. We conclude that changes of crustal transit time forP-waves could be resolved, based on careful PKP arrival time measurement at two or more neighboring stations if the changes exceed 0.05 sec and last for more than one year. The conditions for achieving this result are that PKP from Tonga earthquakes is clearly recorded, and that time-keeping is accurate. The data on which these conclusions are based were obtained from the Graefenberg seismograph array, which is located in West Gemany and consists of 13 stations separated by distances of 10 km to 100 km. We propose that relative arrival times of PKP from Tonga could be used in the Mediterranean - Middle East area to search for precursory travel time changes before large earthquakes.     

Carbon and hydrogen isotopic compositions of the NBS 22 and NBS 21 stable isotope reference materials: An inter-laboratory comparison

Measurement of 17 laboratories on the stable isotope reference materials, NBS 22 lubricating oil and NBS 21 graphite, resulted in a revised calibration on the PDB scale. NBS 22 ¹³C/¹²C ratios of all laboratories did not demonstrate a gausssian distribution. Therefore, values which resulted from direct comparison with NBS 20 carbonate standards were selected the mean value of which is $\text{?29.81 ± 0.06?}$; this value is recommended as new value for NBS 22. The reported variations in δ¹³C for NBS 21 were consistent within the accuracies for single meaurements; the mean value is ?28.16 ± 0.01. The variations of D/H ratios of NBS 22 also were consistent with the accuracy quoted, with a mean value of ?119?.     

Comment on 'The magnetotelluric phase tensor' by T. Grant Caldwell, Hugh M. Bibby and Colin Brown

We demonstrate a minor inconsistency in the appendix of 'The magnetotelluric phase tensor' by Caldwell et al. that can lead to incorrect results, and provide a simple solution for this problem.     

Zur Struktur der Wolken

Zusammenfassung Die vonRittberger aufgestelleten Arbeitshypothesen über den Zusammenhang zwischen Tropfenspektren und Niederschlag gelten primär für den Feldberg (Schwarzwald, 1500 m ü. NN.). Die vorliegenden Messungen vom Jungfraujoch (3550 m ü. NN.) ergänzen und bestätigen im allgemeinen die Ergebnisse vonRittberger. Die Mittelwerte der Wolkenelemente schwanken etwa in den gleichen Grenzen. Auf Jungfraujoch sind breite Spektren etwas häufiger und die Tropfenanzhal geringer als auf dem Feldberg. Die Grenzwerte zwischen Tropfendurchmesser und Temperatur erfahren eine wesentliche Erweiterung zu tieferen Temperaturen.Die Hochnebellagen auf Jungfraujoch sind durch Stau bedingt, und die Tropfengröße ändert sich von der Wolkenuntergrenze (klein) zur Wolkenobergrenze (groß). Die Gleichgewichtsgröße an der Wolkenobergrenze wird durch die darüber liegende Bewölkung bestimmt.Auf Jungfraujoch überwiegen die breiten Spektren, schmale scheinen an Wolkenunter- und-obergrenzen gebunden zu sein. Dabei ist schwer zu entscheiden, inwieweit geschmolzene Kristalle breite Tropfenspektren vortäuschen. Eindeutig ist das starke Überwiegen breiter Spektren bei großräumigem Niederschlag im Tal.Diese Feststellung läßt sich bei der Bearbeitung der einzelnen Wetterlagen bestätigen. Ergiebige Regen im Tal sind mit starken Abkühlungen in der freien Atmosphäre und breiten Tropfenspektren verbunden. Dabei tritt mit Einsetzen des Regens im Tal in drei von vier Fällen auf dem Jungfraujoch ein Rückgang der Tropfenanzahl um eine Zehnerpotenz ein.

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Summary Rittberger's working hypotheses on the relation between drop spectra and precipitation are primarily valid for the Feldberg (Black Forest, 1500 m a. s. l.). The present measurements from Jungfraujoch (3550 m) complete and confirm in general the results ofRittberger. The mean values of cloud elements vary in about the same limits. On Jungfraujoch broad spectra are slightly more frequent and the number of drops per unit is smaller than on the Feldberg. The limits between drop diameter and temperature show a considerable extension towards lower temperatures.The layers of elevated fog on Jungfraujoch are conditioned by barrage and the drop size varies from the lower (small drops) to the upper (larger drops) cloud border. The equivalent quantity at the upper cloud border is determined by the cloudiness above.On Jungfraujoch broad spectra prevail, small ones seem to be restricted to lower and upper cloud borders, whereby it is difficult to decide, in how far melted crystals give the impression of broad drop spectra. Strong prevailing of broad spectra with large-scale precipitation in the valley is well established.This result is confirmed by a discussion of the weather situations. Rich precipitations in the valley are combined with considerable cooling in the upper air and broad drop spectra. Precipitatons in the valley are on Jungfraujoch in three of four cases accompanied by a reduction of the drop number with a power of ten.

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Résumé Les hypothèses de travail établies parRittberger sur les rapports existant entre le spectre des gouttes et les précipitations ne sont valables, à l'origine, que pour le Feldberg (Forêt Noire, 1500 m d'altitude). Les mesures effectuées au Jungfraujoch (3550 m), mesures qui sont présentées ici, viennent compléter et en général confirmer les résultats obtenus parRittberger. Les valeurs moyennes des éléments de nuages oscillent à peu près entre les mêmes limites. Les spectres largement étalés sont un peu plus fréquent et le nombre des gouttes plus petit au Jungfraujoch qu'au Feldberg. Les valeurs limites entre le diamètre des gouttes et la température s'étendent notablement en direction des basses températures.Les situations de brouillard élevé sont provoquées au Jungfraujoch par un effet de barrage et la grosseur des gouttes augmente de la base (petites gouttes) au sommet (grosses gouttes) du nuage. La valeur d'équilibre à la limite supérieure des nuages est déterminée par la nébulosité située au-dessus.Les spectres largement étalés sont en majorité au Jungfraujoch. Les spectres étroits y semblent liés à la base et au sommet des nuages. Il est cependant difficile de déterminer dans quelle mesure des cristaux fondus donnent l'illusion de spectres largement étalés. Ces derniers sont plus fréquents, et cela de façon absolument certaine, lorsque des précipitations étendues s'abatten en plaine.Cette constatation est confirmée par l'étude des situations météorologiques. Des précipitations abondantes en plaine sont liées à un fort refroidissement de l'atmosphère libre et à des spectres de gouttes largement étalés. Au moment du début des précipitations en plaine, on constate trois fois sur quatre une diminuation d'une puissance de 10 du nombre des gouttes au Jungfraujoch.

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Mit 6 Textabbildungen     

Quasi-periodic burst structure at 2.8 GHz and its relationship to burst morphological parameters

Fifteen examples of quasi-periodic 2.8 GHz burst emission observed at the La Posta Astrogeophysical Observatory during the period December 1966 through May 1973 were identified. The periods of these events and those of 22 additional events previously reported in the literature were plotted against burst morphological parameters. The relationship between period and event energy was found to be considerably weaker than initially reported by Cribbens and Matthews.