Distribution and content of different artifical radio nuclides in the water of the North Sea during the years 1977 to 1981 (complemented with some results from 1982 to 1984)

Summary The measured concentrations of¹³⁷Cs in the water of the North Sea gained during the years 1977 to 1982 largely confirm the results found in the preceding years (Fig. 1). After a distinct maximum in 1978 — brought about by a particularly strong influx during 1977 — the total quantity of¹³⁷Cs present in the North Sea has reced, to around half of these peak values by the year 1982 (Table 1).On the way from the Sellafield Works near the Irish Sea as far as into the North Sea, a strong shift of the¹³⁷Cs:⁹⁰Sr ratio in favour of the⁹⁰Sr can be observed.By following the temporal course of that ratio at different measurement points, a transport time can be deduced of around 3 years between the Sellafield Works and the Pentland Firth; a further year would be needed to reach into the southeastern North Sea.The ratio Cs:Sr furthermore permits, in the southeastern North Sea, a good distinction between the watermasses comming from the north into the North Sea with respect to those that come through the Channel from the South. These masses practically flow side by side until about the entrance to the Skagerrak.The vertical distribution of the¹³⁷Cs shows, as is to be expected, seasonally conditioned differences. However, effects also occur, which — on the basis of the data available to date — do not yet permit a clear explanation.The⁹⁰Sr, as well as the^239+240Pu, present in the North Sea show an analogous distribution scheme compared with that of the¹³⁷Cs. Their concentrations lie far below that of the¹³⁷Cs (⁹⁰Sr 17.5%;^239+240Pu 0.03%).Tritium, on the other hand — with essentially higher concentrations — shows a completely different distribution, because it is principly introduced via the freshwater flowing in from the land.

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Verteilung und Gehalt verschiedener künstlicher Radionuklide im Wasser der Nordsee in den Jahren 1977 bis 1981 (ergänzt durch einige Ergebnisse von 1982 bis 1984)

Zusammenfassung Die in den Jahren 1977 bis 1982 gewonnenen Meßdaten der Aktivitätskonzentrationen von¹³⁷Cs im Wasser der Nordsee bestätigen weitgehend die in den vorhergehenden Jahren gefundenen Ergebnisse (Fig. 1) Nach einem deutlichen Maximum im Jahre 1978 — hervorgerufen durch eine besonders starke Zufuhr im Jahre 1977 —ist die in der Nordsee insgesamt vorhandene Menge an¹³⁷Cs bis zum Jahre 1982 wieder auf rund die Hälfte zurückgegangen (Tab. 1).Auf dem Weg von den Sellafield Works an der Irischen See bis in die Nordsee ist eine starke Verschiebung des¹³⁷Cs:⁹⁰Sr Verhältnisses zugunsten des⁹⁰Sr zu beobachten.Aus dem zeitlichen Verlauf dieses Verhältnisses an verschiedenen Meßpunkten ergeben sich Transportzeiten zwischen den Sellafield Works und dem Pentland Firth von rund 3 Jahren; bis in die südöstliche Nordsee wird ein weiteres Jahr benötigt.Das Verhältnis Cs:Sr erlaubt außerdem in der südöstlichen Nordsee eine gute Unterscheidung der aus der Nordsee bzw. durch den Kanal von Süden kommenden Wassermassen, die praktisch nebeneinander her bis etwa zum Beginn des Skagerraks fließen.Die Vertikalverteilung des¹³⁷Cs zeigt, wie zu erwarten ist, jahreszeitlich bedingte Unterschiede. Es treten aber auch Effekte auf, die sich anhand der bisher vorliegenden Daten noch nicht eindeutig erklären lassen.Das in der Nordsee vorhandene⁹⁰Sr sowie das^239+240Pu zeigen ein analoges Verteilungsschema verglichen mit dem des¹³⁷Cs. Ihre Konzentrationen liegen weit unter der des¹³⁷Cs (⁹⁰Sr 17,5%,^239+240Pu 0,03%).Das Tritium zeigt bei wesentlich höheren Konzentrationen dagegen eine völlig andere Verteilung, da seine Hauptzufuhr im wesentlichen über das von Land her zufließende Süßwasser erfolgt.

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Distribution et teneur de differents radionucleides artificiels, dans les eaux de la Mer du Nord entre les années 1977 et 1981 (completes par quelques résultats de 1982 à 1984)

Résumé Les mesures de concentration du Césium 137 dans les eaux de la Mer du Nord, acquises entre les années 1977 et 1982, confirment largement les résultats obtenus au cours des années précédentes. Après un net maximum en 1978 — occassionné par un apport particulièrement fort en 1977 — la quantité totale de Césium 137 présent en Mer du Nord a régressé,jusqu'en 1982, aux alentours de la moitié de ces valeurs maximales.Il a pu être observé une modification importante du rapport Césium 137/Strontium 90, en faveur du Strontium 90, sur le trajet de Sellafield Works prés de la Mer d'Irlande jusqu'à la Mer du Nord.En suivant l'évolution temporelle de la valuer de ce rapport en différents points de mesure, on peut en déduire une durée de transport d'environ 3 ans entre Sellafield Works et Pentland Firth; une année supplémentaire est ensuite nécessaire pour pénétrer en Mer du Nord Sud-orientale.En Mer du Nord Sud-orientale, le rapport Césium/Strontium permet en outre d'effectuer une nette distinction entre les masses d'eau pénétrant respectivement par le Nord dans la Mer du Nord et celles pénétrant par le Sud et venant de la Manche. Ces masses d'eau s'écoulent pratiquement côte à côte jusqu'à l'entrée du Skagerrak.Comme l'on pouvait s'y attendre, la distribution verticale du Césium est différente suivant les saisons. Cependant il apparaît également des effects qui, sur la base des données disponibles à ce jour, ne s'expliquent pas encore clairement.Le Strontium 90 aussi bien que le Plutonium 239+240 présent dans la Mer du Nord, montrent une distribution comparable, analogue à celle du Césium 137. Leurs concentrations sont bien inférieures à celle du Césium 137 (Strontium 90 17,5%; Plutonium 239+240 0,03%).Le tritium d'autre part, — avec des concentrations significativement plus fortes —montre une distribution complètement différente, due principalement au fait qu'il est introduit par l'intermédiaire de l'écoulement d'eau douce provenant de la terre.

     

Pre-Hercynian mantle lead transfer to basement rocks as indicated by lead isotopes of the Schwarzwald crystalline,SW-Germany

Lead isotopes of K-feldspars from five granites of the SE-Schwarzwald and from metamorphites are positively correlated in 207/204 as well- as 208/204- vs. 206/204-diagrams. The linear alignments may be due to correlated laststage lead isotope evolution (lead-lead isochron) and result in a secondary isochron model age of nearly 3 Ga for the Southern Schwarzwald basement. This calculation implies a long-lasting undisturbed lead isotope evolution in the Schwarzwald basement since the Archaean. This is not supported however by geochronological studies. On the other hand the data together with U/Pb-analyses of whole rock samples from metamorphites are consistent with pre-Hercynian mantle lead addition to the basement. This presumably happened during early Paleozoic polymetamorphism. The interpretation of the lead isotope correlations as mantle-crust mixing lines needs a rather homogeneous pre-Hercynian mantle lead of the MORB-type, delivered to the crust probably in part by ascending volatile phases. Thus geodynamical models are supported which involve subduction of oceanic crust or mantle pluming during the early Paleozoic. In Part I of this report, the trends in Schwarzwald lead isotopes are discussed as secondary isochrons and as mixing lines. Constraints are derived for a pre-Hercynian mantlecrust interaction and for lead redistribution by the Hercynian basement activation.     

Geology and paleontology of late Cenozoic marine deposits in the Sacaco area (Peru)

Paleontologic, stratigraphic and geochronologic (K-Ar) evidence demonstrate the presence of both late Miocene and Pliocene marine deposits in the Pisco Formation in the area of Sacaco, Peru. Tuffaceous sandstone, siltstone, and shelly sandstone comprise the greater part of the ca. 350 meters sequence. The fine grained sediments have accumulated in large coastal lagoons, while coarser sediments were deposited in semiprotected littoral and nearshore environments. A rich marine vertebrate fauna from the Sacaco basin includes fossil selachians, teleost fishes, marine birds, cetaceans, marine carnivores, and a single edentate species. A diverse invertebrate fauna consists principally of venerid and muricid molluscs. Five vertebrate levels have been correlated with five provisionally defined molluscan zones. The vertebrate fauna has some affinity with faunas of the Miocene Yorktown Formation at the Lee Creek Mine of North Carolina (USA). Distinctive Miocene and Pliocene molluscan assemblages of the Pisco Formation and Pleistocene molluscan assemblages from overlying terrace deposits become progressively more similar to Chilean assemblages of equivalent age and less similar to Tethyan faunas of the Panamic and Caribbean regions.

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Zusammenfassung Paläontologische, stratigraphische und geochronologische (K-Ar) Daten belegen ein obermiozänes und pliozänes Alter der Pisco-Formation. Die Sequenz wird etwa 350 m mächtig und besteht aus tuffartigen Sandsteinen, Silten und Schillsanden. Die feineren Sedimente sind in großen Lagunen, die gröberen im geschützten Strandbereich abgelagert worden. Die reiche Fauna enthält Fische (Teleostei und Selachii), Meeres-Vögel, eine Edentata und an Wirbellosen hauptsächlich Veneriden und Muriciden. Fünf Wirbeltier-Horizonte lassen sich mit fünf vorläufig definierten Molluskenzonen korrelieren. Die Vertebratenfauna ähnelt der aus dem Unterpliozän von Nordkarolina (Yorktown Formation und Lee Creek Mine Formation — USA). Vom Miozän zum Pliozän verändert sich der Charakter der Molluskengesellschaften vom panamensisch-karibischen zu chilenischem Gepräge.

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Résumé Des preuves paléontologiques, stratigraphiques et géochronologiques (K-Ar) démontrent la présence de dépôts miocènes supérieur aussi bien que pliocènes dans la Formation Pisco dans la région de Sacaco (Pérou). La séquence est d'environ 350 mètres et se compose de grès tuffacés, de microgrès et de grès coquillers. Les sédiments à grains fins se sont accumulés à l'intérieur de grands lagons côtiers tandis que les sédiments plus grossiers furent déposés dans des environnements abrités littoraux et côtiers. La faune de Vertébrés de la région de Sacaco est riche et comprend essentiellement des Sélaciens, des Téléostéens, des Oiseaux marins et un Edenté. La faune d'Invertébrés est variée et se compose principalement de Mollusques Vénéridés et Muricidés. Cinq niveaux de Vertébrés ont été corrélés avec cinq zones de Mollusques définies provisoirement. La faune de Vertébrés présente des affinités avec celle de la Formation Yorktown du Pliocène inférieur de Lee Creek Mine en Caroline du Nord (USA). Les associations caractéristiques de Mollusques miocènes et pliocenes de la Formation Pisco et celles des dépôts de terrasses quaternaires sus-jacents sont de bas en haut, progressivement plus semblables aux associations chiliennes du même âge, différant des faunes téthysiennes des provinces panam eennes et caraïbéennes.

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, ( -) Pisco . 350 , . , , , - . : (Teleostei Selachii), , Edentata, — . . Venerideae Muricideae. 5 , , . ( Yorktown Lee Creek Mine, ). .

     

Observations on Gulf of Alaska seamount chains by multi-beam sonar

Geomorphic and age data are presented for the Dellwood, Denson, Dickins, Giacomini, and Ely seamounts, the Tsimshian Seachannel, and the southern Juan de Fuca Ridge with Brown Bear, Bear Cub, Grizzly Bear, and Cobb seamounts. Formational speculations extrapolated to a regional scale allow the strikes and outer limits of the seamount chains to be interpreted. Six of these chains are shown in the Gulf of Alaska, none of which conform to the Pratt-Welker or Kodiak-Bowie in the literature. Different strikes show the chains/plate to have rotated 23° about 17 m.y. ago. Morphology also shows that there are four less guyots in the Gulf than previously thought, and that, at least in the Gulf of Alaska, guyot heights do not necessarily reflect sealevel during erosion.     

A comparative study of observed and GCM-simulated turbulent surface fluxes at the positions of Atlantic weatherships

If oceanic models are to be driven with transient atmospheric input, data from standard daily analyses or from an atmospheric GCM simulation can be used. The question arises whether these “FF-data” (FF = field forcing) are appropriate to be used as a realistic oceanic forcing in the form of wind stress and turbulent heat fluxes.A series of different FF-data sets is compared with respective “LF-data” (LF = local forcing) derived from in situ weathership observations. We believe these LF data to be the most accurate and reliable long year maritime time series. The study is restricted to 8 Atlantic weatherships and January conditions and to fields obtained with the Hamburg University GCM or derived from analyses of the German Weather Service (DWD).It turns out that DWD based FF data sets are suitable only if long year mean values are required. In general, the interannual and synoptic scale variability is too small for all FF data sets. With respect to the windstress, the empirical formulae to obtain the surface wind (from the sea level pressure field) together with the usage of a windspread dependent drag coefficient yield the best though still unsatisfying results. The approach using generalized similarity theory gives worse results with respect to the synoptic scale and interannual variability.The GCM simulated data set is systematically biased over wide regions which is partly due to a shift in the model's quasistationary Icelandic Low and an increased temperature at the model's lowest level. The transients are simulated at some positions even poorer than those analysed by the DWD, but at other positions superior though still weaker than the LF data's.     

Least squares parameter estimation in chaotic differential equations

A recent least squares algorithm, which is designed to adapt implicit models to given sets of data, especially models given by differential equations or dynamical systems, is reviewed and used to fit the Hénon-Heiles differential equations to chaotic data sets.This numerical approach for estimating parameters in differential equation models, called theboundary value problem approach, is based on discretizing the differential equations like a boundary value problem,e.g. by a multiple shooting or collocation method, and solving the resulting constrained least squares problem with a structure exploiting generalized Gauss-Newton-Method (Bock, 1981).Dynamical systems like the Hénon-Heiles system which can have initial values and parameters that lead to positive Lyapunov exponents or phase space filling Poincaré maps give rise to chaotic time series. Various scenarios representing ideal and noisy data generated from the Hénon-Heiles system in the chaotic region are analyzedw.r.t. initial conditions, parameters and Lyapunov exponents. The original initial conditions and parameters are recovered with a given accuracy. The Lyapunov spectrum is then computed directly from the identified differential equations and compared to the spectrum of the true dynamics.presently at IWR, Universität Heidelberg, Im Neuenheimer Feld 368, D-6900 Heidelberg, Germany     

The ?resund Area: Pre- and post-bridge cross-border functional integration: The bi-national regional question

Copenhagen in Denmark and Malmö in Sweden were connected in 2000 by the 18- km fixed Öresund link. This meant that the time distance-barrier was reduced dramatically and that the land-sea bottleneck was eliminated. High-profile pre-bridge expectations of a new regional development regime towards a functionally integrated, bi-national region are assessed in this paper. The paper relates to the continuing discussion on development of border-regions and bi-national cities. Data on cross-Öresund flows of people and vehicles, together with data on migration and commuting, indicates a modest post-bridge shift in the development of functional integration. The Öresund Area development towards a bi-national, integrated, functional urban region is in progress, but the progress is much slower than expected.     

Assessing streams in Germany with benthic invertebrates: Development of a multimetric invertebrate based assessment system

The main aim of the study was to develop a multimetric assessment system for macroinvertebrate communities of small and mid-sized streams in Germany in accordance with the Water Framework Directive of the European Union. The system should be applicable by water authorities, capable of distinguishing between different impacts, and specifically adapted to all types of small and mid-sized rivers in Germany. An assessment system has been developed consisting of two modules based on the established indices for saprobic degradation and acidity, and a third module covering general degradation. For the third module a new multimetric index (MMI) was developed and tested using preclassifications for stream hydromorphological degradation, land use and general impairment as impact measures. More information on sampling method, season and the type of dominating human impairment allowed to further analyse the index' capabilities and sensitivity. It performed well in all seasons and detected all types of impairment except acidity. The usefulness of the impact measures used in this study is discussed with regard to the development of a multimetric index. The comparison of the new index with other indices showed that it is especially sensitive in detecting macroinvertebrate community responses to hydromorphological degradation and pollution such as the German AQEM index, while IBI 12 and Renkonen's similarity more reflect general community shifts caused by any type of disturbance. The new assessment system will be proposed for future use by state agencies for nationwide monitoring in the context of the Water Framework Directive implementation.