Volatile Organic Compounds in Various Marine Organisms From the Southern North Sea

The concentration levels of 12 priority volatile organic compounds (VOCs) were determined in two species of vertebrates and four species of invertebrates from sampling stations in the southern North Sea, using a modified Tekmar LSC 2000 purge and trap system coupled to gas chromatograph–mass spectrometer (GC–MS). In general, concentration levels of VOCs found in this study were of the same order of magnitude as those previously reported in the literature. The concentrations of the chlorinated hydrocarbons (CHCs), with the exception of chloroform, tended to be lower than those of the monocyclic aromatic hydrocarbons (MAHs). The experimental data were statistically evaluated using both cluster analysis and principal component analysis (PCA). From the results of cluster analysis and PCA, no specific groups could be distinguished on the basis of geographical, temporal or biological parameters. However, based on the cluster analysis and the PCA, the VOCs could be divided into three groups, C₂-substituted benzenes, CHCs and benzene plus toluene. This division could be related to different types of sources. Finally, it was shown that organisms can be used to monitor the presence of VOCs in the marine environment and the observed concentrations levels were compared with proposed safety levels.     

The slope movements within the Mondorès graben (Drôme, France); the interaction between geology, hydrology and typology

The Mondorès graben in the south-eastern French Alps is an uncommon structural feature, which originates in a complex polyphasic tectonic evolution. In contrast with its immediate surroundings, with hardly any huge landslides, the Mondorès graben is characterised by various types of landslides. A huge sagging caused part of the limestone cliff to subside some 50 m within 50 years. Two recent mud flows that occurred were considered a potential threat to some inhabited places downstream. The hydrologic aspects of the Boulc-Mondorès landslide resemble the geology: infiltration (and karst input?) in the rock-sliding zone and exfiltration in the marls resulting in slumps and mud flows. The mass movement interactions could be explained by a structural geology analysis with geodetic monitoring using different techniques. It is also shown that hydrochemistry as well as geophysical surveys are of importance in unravelling the hydrologic systems and the geological subsurface structures. The present paper aims at explaining the geological control of the different slides in view of estimating their potential danger. Understanding the geological structure and its evolution therefore is a necessary prerequisite.     

Periodic motions around a collinear equilibrium solution of the general three-body problem

The collinear equilibrium position of the circular restricted problem with the two primaries at unit distance and the massless body at the pointL ₃ is extended to the planar three-body problem with respect to the massm ₃ of the third body; the mass ratio μ of the two primaries is considered constant and the constant angular velocity of the straight line on which the three masses stay at rest is taken equal to 1. As regards periodic motions ‘around’ the equilibrium pointL ₃, four possible extensions from the restricted to the general problem are presented each of them starting with a simple or a doubly periodic orbit of the family α of the Copenhagen category (μ=0.50). Form ₃=0.10, μ=0.50 (i.e. for fixed masses of all three bodies) the characteristic curve of the extended family α is found. The qualitative differences of the families corresponding tom ₃=0 andm ₃=0.10 are discussed.     

Guangnan (L6) and Ningqiang (CV3): Exposure Ages and Radiogenic Ages of Two Unusual Chondrites

Abstract— The isotopic abundances of the noble gases in bulk samples of the Guangnan L6 chondrite and of the anomalous CV3 chondrite Ningqiang were measured. Guangnan yields a cosmic-ray exposure age of 2.9 ± 0.4 Ma and belongs to the group of L chondrites with low exposure ages. Ningqiang, however, shows a cosmic-ray exposure age of 42.2 ± 4.0 Ma, the highest for a CV3 chondrite. The concentrations of radiogenic ⁴He and ⁴⁰Ar in Guangnan are the lowest observed in any ordinary chondrite. A U/Th-⁴He age of 27 ± 16 Ma and a ⁴⁰K–⁴⁰Ar age of 142 ± 14 Ma are calculated assuming L chondritic U, Th, and K concentrations. This assumption is justified considering the fact that a mineralogical composition typical for L chondrites was reported for this meteorite. The observed severe gas losses must have occurred at or before the onset of the exposure of the meteoroid to the cosmic radiation. For the Ningqiang carbonaceous chondrite concordant gas retention ages are obtained: The U/Th-⁴He age is 4170 ± 160 Ma whereas the ⁴⁰K–⁴⁰Ar age is 4260 ± 70 Ma, assuming average U, Th, and K concentrations for C3 chondrites.     

Karibibite,a new FeAs mineral from South West Africa

Karibibite (ideally, Fe₂As₄O₉) occurs in vugs in massive loellingite of the Karibib pegmatite area, South West Africa. It is brownish yellow and finely fibrous. The thickness of the soft, single fibers is less than 1 micron, unsuitable for single-crystal X-ray study. Electron diffraction and X-ray powder pattern indicate that the mineral is orthorhombic, with $\text{a}{}_0\text{= 27.91}\text{A}\text{?}\text{, b}{}_0\text{= 6.53}\text{A}\text{?}\text{and c}{}_0\text{(}\text{fiber axis}\text{) = 7.20}\text{A}\text{?}$. The space group cannot be given. The mineral is paramagnetic with yellow fluorescence and is pleochroic with γ > 2.10, α = 1.96, 2V_α large, d = 4.07. It is soluble in acids and alkali hydroxide. Decomposition starts around 320 °C. The infra-red absorption spectrum indicates absence of AsO₄ groups. The mineral is classified tentatively as an oxide or arsenite.     

Cyanophycées marines endolithes colonisant les surfaces rocheuses dénudées (Etages Supralittoral et Médiolittoral de la région de Marseille)

Résumé Etude des Cyanophycées endolithes, recolonisant les surfaces rocheuses dénudées, au niveau des Etages Supralittoral et Médiolittoral de la région de Marseille. Apparition de différentes formes évolutives de l’espèceEntophysalis deusta en fonction de l’intensité des facteurs du milieu. Niveau de l’Etage Supralittoral, humectation réduite, formes épilithes et peu pénétrantes; niveau de l’Etage Médiolittoral, humectation intense, formes endolithes filamenteuses. Il est à noter que ces formes se succèdent toujours dans le même ordre, seul le stade final est différent selon la condition du milieu envisagé. Ceci va donc à l’encontre d’une espèce unique avec divers stades évolutifs. La position extrême adoptée parF. Drouet etW.A. Daily au sujet de la systématique des Cyanophycées endolithes entra?ne de nombreuses réserves et seule une étude basée sur des cultures unialgales permettra de conna?tre avec précision la marge de variation des taxons.

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Summary The object of this study was the endolithic blue-green algae of the upper and middle litoral zone of the rocky coast near Marseille. Difficulties in determining these algae cropped up very soon because of their strong plasticity. To ascertain whether there were different species of algae or only different ecological types of the same species, two series of experiments were carried out in the region around Marseille: 1. small rock splinters from various places were cemented into place in the above-mentioned zones. 2. The regrowth of rock surfaces that were cleared of algae was observed. Moreover cultures of the individual species were made to find an unequivocal solution to the systematic and ecological problems of these algae. Only the results of the tests on recolonization of the rock surface by algae are dealt with in this paper. According to our observations, theEntophysalis deusta (Men.) Drouet and Daily developed in different patterns depending on the degree of moisture. In the upper litoral zone where the amount of moisture is less significant it takes on epilithic forms that do not penetrate into the rock. In the more humid middle zone they prevail in an endolithic stringy form. It is interesting to note that the various forms always appear in the same order; thus with increasing moisture one finds:Gloeocapsa, Entophysalis, Scopulonema (forms of the upper litoral zone) andHyella caespitosa, Hyella tenuior (forms of the middle zone). Other species such as theHormathonema that grow in the same biotope as theEntophysalis seem to react differently to outside stimuli. The conjectures concerning the plasticity of theEntophysalis deusta confirmDrouet andDaily’s theory. Yet this hypothesis needs to be confirmed through cultures of the forms observed.

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Zusammenfassung Die endolithischen Blaualgen der supralitoralen und mediolitoralen Zone an der felsigen Küste in der Region von Marseille wurden untersucht. Schon zu Beginn der Arbeit zeigten sich Schwierigkeiten bei der Bestimmung dieser Algen, da sie zum Teil eine starke Plastizit?t aufzuweisen scheinen. Um abzukl?ren, ob verschiedene Arten oder nur unterschiedliche ?kotypen ein, und derselben Art vorliegen, wurden zwei Untersuchungsserien in der Region von Marseille durchgeführt: 1. Kleine Felssplitter verschiedener Herkunft wurden in den genannten Zonen festzementiert. 2. Es wurde beobachtet, wie Stellen, die man von Algen entbl?sste, wieder besiedelt wurden. Ferner begann man Kulturen der einzelnen Typen herzustellen, um die systematisch-?kologischen Probleme dieser, Blaualgen eindeutiger zu l?sen. In dieser Mitteilung sind nur die Resultate derWiederbesiedlungsversuche dargestellt. Die Beobachtungen ergaben im wesentlichen, dass die ArtEntophysalis deusta (Men.) Drouet et Daily sich je nach Intensit?t der Benetzung in verschiedenen Formen entwickelt. So tritt sie in der supralitoralen Zone, die einen reduzierten Feuchtigkeitsgrad aufweist, in epilithischen Formen auf, die wenig in den Fels eindringen. In der mediolitoralen Zone mit grosser Feuchtigkeit findet man sie als endolithische f?dige Formen. Interessant ist, dass diese verschiedenen Erscheinungsformen stets in gleicher Reihenfolge auftreten, und zwar begegnet man mit zunehmender Feuchtigkeit folgenden Formen:Gloeocapsa, Entophysalis, Scopulonema (= Formen der supralitoralen Zone),Hyella caespitosa, Hyella tenuior (= Formen der mediolitoralen Zone). Andere Gattungen, wie z. B.Hormathonema, die im gleichen Biotop wieEntophysalis auftreten, scheinen anders auf die Umweltfaktoren zu reagieren. Die Vermutungen über die Plastizit?t vonEntophysalis deusta best?tigen eigentlich die Auffassung vonDrouet undDaily. Doch diese Hypothese verlangt eine Best?tigung mittels Kulturen der beobachteten Erscheinungsformen.

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Contribution à l’étude des Cyanophycées lithophytes des Etages Supralittoral et Médiolittoral (région de Marseille), Tethys1 (1), 119–172 (1969).