Nutrient transports in a Swedish estuary

Himmerfjärd is a Swedish estuary bordering on the Baltic. The estuary lacks astronomical tides and its circulation is driven by winds and freshwater runoff. Because of a tertiary sewage treatment plant located at its inner end, the estuary is becoming increasingly eutrophic. A field study was carried out for a 78-day period in late summer and early fall of 1977 to determine rates of nutrient transport and to construct nutrient budgets. Since physical parameters (current velocity, temperature, salinity, winds and water level changes) were measured more frequently than nutrients (phosphate, nitrate, nitrite and ammonium) it was necessary to develop a suitable method to calculate nutrient flux time series and net nutrient fluxes. Over the study period, Himmerfjärd imported phosphorus and exported nitrogen. Direction of nutrient fluxes and changes in flux direction were consistent with the structure of the baroclinic currents.     

A comparison of chemical and chemodynamical models

Representative results from a comparison of the chemical evolution of spherical collapse models without and with a intercloud medium are presented. The hot metal-rich gas distributes quickly the metals produced in supernovae throughout the galaxy, thus leading to a more homogeneous chemical evolution and flatter metallicity gradients in the gas and the stars. The stellar population is somewhat less concentrated towards the centre. The strong outflow results in a substantial loss of metals from the galaxy to its surroundings, and a lower effective yield in the galaxy. This revised version was published online in August 2006 with corrections to the Cover Date.     

Galaxy formation: Warm dark matter, missing satellites, and the angular momentum problem

We present warm dark matter (WDM) as a possible solution to the missing satellites and angular momentum problem in galaxy formation and introduce improved initial conditions for numerical simulations of WDM models, which avoid the formation of unphysical haloes found in earlier simulations. There is a hint, that because of that the mass function of satellite haloes has been overestimated so far, pointing to higher values for the WDM particle mass. This revised version was published online in August 2006 with corrections to the Cover Date.     

On the non-linear stability of motions around L5 in the elliptic restricted problem of the three bodies

The non-linear stability of motions around L₅ in the elliptic restricted problem of the three bodies is investigated numerically with emphasis on the effect of the orbital eccentricity of the primaries on the shape of the established stability regions. It is shown that with increasing eccentricity, the width of these regions is decreasing.     

A comparison of artificial solar granules with real solar granules

The lifetimes, characteristics of the shapes as well as lengths and perimeters of artificial solar granules (Nordlund, 1982, 1984a) are compared with data from the literature and parameters determined from two different sets of observed granules. No significant differences of the parameters for these sets of granules are detectable.Mitteilungen aus dem Kiepenheuer-Institut Nr. 251.     

Survival,growth and shell deformities of copper- and cadmium-exposed mussels (Mytilus edulis L.) in brackish water

Mussels, Mytilus edulis L., were exposed to elevated concentrations of copper or cadmium in the laboratory, then placed in cages in the sea (salinity 7‰). One year later maximum lengths of the mussels were measured and shells screened for deformities. Growth was 0·6 cm year^?1 in the control cages and retarded in cages of exposed mussels. A total of 63% of cadmium-exposed and 46% of copper-exposed mussels had shell deformities. In the control cages 26% were deformed while in a natural population only 3% were deformed. The proportion of deformities to growth was inversely related. Low concentrations showed their injuriousness in this long-term test, probably due to the closing of the valves during exposure to high concentrations.     

The solar differential rotation: Present status of observations

The present status of observations regarding the solar differential rotation is reviewed from contributions published in the last two decades. The paper does not deal with the theory; it mentions theoretical aspects only where they are needed to guide and to understand observational efforts and results.Mitteilungen aus dem Kiepenheuer-Institut Nr. 250.     

Radon variations in a Hungarian village

 A steady radon exhalation is assumed in most publications. In a village of North-East Hungary, however, high radon concentrations have been measured, differing strongly in neighbouring houses and varying in time, due to the interplay of geochemical phenomena. Received: 20 November 1995 · Accepted: 18 June 1996     

African linkage of Precambrian Sri Lanka

New age and isotopic data show that the high-grade basement rocks of Sri Lanka were not linked to the Archaean granulite domain of southern India but experienced their main structural and metamorphic development during the Pan-African event some 950 to 550 Ma ago. This occurred when West Gondwana and East Gondwana collided to form one of the longest collisional structures in the Supercontinent — the Mozambique belt that extends from Mozambique to Ethiopia and Sudan. A major tectonic boundary, interpreted as a thrust zone, divides the Highland/Southwestern Complex in the central part of Sri Lanka from the Vijayan Complex in the E and SE. The former is interpreted to represent the remnant of a once extensive passive margin extending west, in a Gondwana reconstruction, via Madagasgar to Tanzania and Mozambique. The Vijayan Complex may have been part of a separate continental margin plutonic assemblage, and its collision with the Highland/ Southwestern Complex marks the final amalgamation of East and West Gondwana into a supercontinent some 550 Ma ago. The Sri Lankan granulites cannot be correlated with the distinctly older granulites of the Eastern Ghats belt of India, and this suggests that Sri Lanka was situated close to the SE coast of Madagascar in a Gondwana reconstruction.

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Zusammenfassung Neue Isotopen- und Altersdaten aus dem metamorphen Grundgebirge von Sri Lanka zeigen, daß dieses Gebiet nicht, wie vielfach vermutet, Teil des archaischen Granulitkomplexes von Südindien war, sondern seine strukturelle und metamorphe Entwicklung während der panafrikanischen Orogenèse zwischen ca. 950 Ma und ca. 550 Ma hatte. Diese Orogenèse ist das Resultat der Kollision zwischen West-Gondwana (Afrika und Südamerika) und Ost-Gondwana (Südindien, Australien und Antarktis) und führte zur Bildung eines der längsten Kollisionsgürtel des Superkontinentes, dem Mosambik-Gürtel, der sich von Mosambik bis nach Äthiopien und in den Sudan erstreckt. Der West- und Zentralteil Sri Lankas mit den Wanni und Highland/Southwestern Komplexen wird vom Vijayan Komplex im Osten und Südosten durch eine Überschiebungszone getrennt, die möglicherweise eine Sutur darstellt. Die Gesteine im Westen und in den Highlands werden als der Rest eines ehemals weiträumigen passiven Kontinentalrandes interpretiert, zu dem wohl auch die lithologisch ähnlichen Abfolgen der hochmetamorphen Gebiete in Mosambik, Tansania und Madagaskar gehörten. Der Vijayan Komplex war wohl Teil der separaten plutonischen Suite eines aktiven Kontinentalrandes, und seine Kollision mit dem Highland/ Southwestern Komplex markiert das endgültige Verschweißen von West- und Ost-Gondwana zu einem Superkontinent vor ca. 550 Ma. Die Granulite Sri Lankas können nicht mit den deutlich älteren Granuliten des Gürtels der Eastern Ghats in Südost Indien korreliert werden sondern ähneln eher den hochgradigen Gesteinen in Südost Madagaskar. Damit ist die Lage Sri Lankas nahe Madagaskar in einer Gondwana Rekonstruktion wahrscheinlicher als nahe der Südostküste Indiens.

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Résumé De nouvelles données isotopiques et géochronologiques montrent que les roches métamorphiques du socle du Sri Lanka ne constituent pas, comme on l'a souvent cru, une partie du complexe granulitique archéen de l'Inde méridionale, mais qu'elles ont vécu leur propre histoire tectono-métamorphique au cours de l'orogenèse panafricaine, entre 950 et 550 Ma. Cette orogenèse est le résultat de la collision entre le Gondwana occidental (Afrique et Amérique du Sud) et le Gondwana oriental (Inde du sud, Australie et Antarctique) et constitue une des plus grandes chaînes de collision du Supercontinent: la chaîne du Mozambique, qui s'étend du Mozambique jusqu'au Soudan et en Ethiopie. Un contact tectonique majeur, interprété comme un charriage, sépare le »Highland/South-western Complex« (partie centrale du Sri Lanka) du »Vijayan Complex« (partie est et sud-est). Le premier de ces complexes est interprété comme un reste d'une ancienne marge passive de grande étendue, à laquelle appartenaient aussi les séries lithologiquement analogues du domaine très métamorphique du Mozambique, de Tanzanie et de Madagascar. Le «Vijagan Complex« a pu être une partie d'un ensemble plutonique séparé de marge active; sa collision avec le »Highland/Southwestern Complex« marque la réunion finale en un super-continent il y a quelque 550 Ma, des Gondwanas oriental et occidental. Les granulites du Sri Lanka ne peuvent pas être corrélées avec celles de la chaîne des Eastern Ghats (Inde du sud-est) qui sont nettement plus anciennes; elles se rapprochent plutôt des roches très métamorphiques du sud-est de Madagascar. On en déduit que la position du Sri Lanka, dans une reconstruction du Gondwana, devait être plus proche de Madagascar que de la côte sud de l'Inde.

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