Hydrogeochemistry of two river main floodplain lakes,Hessia, FR Germany

Two lakes, Lake Gänseweiher (LGW) and Lake Fechenheimer Weiher (LFW) occupy groundwater filled abandoned gravel pits which serve as fishing grounds and are part of recreational areas, respectively.Both lakes are cut into a near-surface groundwater aquifer, which is located in the pleistocene River Main gravel terrace t₆. They are sealed at the base by miocene clays and above by overlying flood deposits of the River Main. The latter provide protection from pollutants derived from wet and dry deposition of atmospheric contaminants.Groundwater chemistry determines the pool of dissolved constituents in lake water. The temporal and spatial distribution patterns of chemical compounds in lake water are brought about by endo-biogenic processes, of which the indicators are nitrate-nitrogen and dissolved silica. The latter illustrates an instantaneous response to pulses of diatom blooms.Both lakes are eutrophic (polytrophic) according to the classification guidelines presented in literature.     

Die tektonische Evolution der Erde von Pangäa zur Gegenwart ein plattentektonisches Modell

Zusammenfassung Das hier vorgestellte Modell basiert auf der Annahme, daß sich unter großen Landmassen, wie Pangäa zum Beispiel, in tektonischen Ruheperioden Wärme aus dem Erdinneren anstaut. Infolgedessen entwickelte sich vom Perm bis zur Kreide ein weites Konvektionstumorsystem; Pangäa zersplitterte und die kontinentalen Platten bewegten sich vom afrikanischen Zentrum weg. Die ozeanischen Rücken des Atlantiks und Indiks folgten den abwandernden Platten wie sich »öffnende Ringe«. Panthalassa, der Eo-Pazifik, wurde von allen Seiten überdriftet. Es muß einen Gegenstrom vom Pazifik im Mantel geben, welcher für die Auffüllung der zwischen den Pangäabruchstücken entstehenden ozeanischen Räume mit Mantelmaterial sorgt. Auch die ozeanischen Platten des Pazifiks bewegen sich vom zentralen »Darwin-Rise« weg. Der ostpazifische Rükken folgte der Bewegung und bildet heute einen ausgedehnten ostwärts gekrümmten Bogen. In den ozeanischen »Außenbögen« bildeten sich infolge der Dehnung Querrifts. Die Transformstörungen sind in beiden Systemen radial angeordnet. Die Terrains an Nordamerikas Westküste können nur östlich eines ostpazifischen Rückens aus ihrer ursprünglichen Position im zentralen Pazifik herausgewandert sein, also synchron mit dem sich öffnenden Pazifik. Die Kontinente bewegen sich möglicherweise solange von ihrer ursprünglichen Position weg, bis erneut eine große Landmasse zusammengedriftet ist. Unterhalb einer solchen »Neogäa« könnte sich wieder ein Konvektionstumor infolge von Wärmestau entfalten. Das findet vielleicht in Intervallen von einigen hundert Millionen Jahren statt und könnte die WILSON-Zyklen der Erdgeschichte erklären.

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The tectonic evolution of the earth from Pangea to the present a plate tectonic model

The model proposed here is based on the assumption that beneath giant landmasses (e.g. Pangea) heat from the inner earth is stored up and accumulated during periods of tectonic inactivity. Consequently below Pangea a huge convection bulge system developed from the Permian to the Cretaceous; Pangea split up and the continental plates moved away from the African centre. The oceanic ridges of the Atlantic and the Indic also followed the movement of the withdrawing continents like »opening rings«. The oceanic ridges always maintained their position in the middle of the spreading oceans above unidirectional flows in the upper mantle. Panthalassa which surrounded Pangea, was over-drifted from all sides. Since the »expansion« of Pangea is continuing even today, there must be a counter current of mantle material from the Pacific area, compensating the gaps between the fragments of Pangea. Consequently at the subduction zones a suction should exist, which pulls the Pacific plates under the advancing plates of the former Pangean continent. In the centre of Panthalassa another bulge from the upper mantle developed simultaneously with the bulge under Pangea. The Pacific oceanic plates moved away outwards from this central »Darwin rise«. The Eastpacific ridge also followed this movement eastwards and forms today a wide, ringlike arc. In the outer arcs of the Pangean and Pacific spreading ocean systems transverse ridges developed as a result of the extension of the older oceanic crust. The transform faults are radial structures in both »expanding« systems. The hotspot spurs of the Hawaii and Polynesian islands can be explained as the result of material derived from an independent slowly ESE moving deeper part of the mantle. The terrains on North Americas West cost moved away from their original position in the central Pacific ocean synchronously with the opening ocean on the east side of the advancing East Pacific ridge.The energy which drives the whole system is residual plus radioactive heat. Kinetic movements compensate the heat surplus of the earth. The continental plates of the Pangean system are moving away from their original position until a new giant landmass is formed by collision. Below such a stationary »Neogea« a heat bulge can develop again. This may take place perhaps in intervals of hundred of million years, explaining the WILSON-cycles in earth history.

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Résumé Le modèle présenté ici est basé sur l'hypothèse qu'endessous des grandes masses continentales — comme la Pangée p.ex. - il s'accumule, pendant les périodes de calme tectonique, de la chaleur d'origine interne. En conséquence, depuis le Permien jusqu'au Crétacé, un vaste système de convection s'est développé; la Pangée s'est morcelée et les plaques continentales se sont éloignées du centre africain. Les dorsales océaniques circum-africaines ont suivi le mouvement de ces plaques à la manière d'»anneaux concentriques«. La Panthalassa, précurseur du Pacifique, a été chevauchée de tous les côtés. Il doit s'être établi, dans le manteau, à partir du Pacifique, un contre-courant qui compense l'ouverture des océans en formation entre les fragments de la Pangée. Le Pacifique a donné lieu, lui aussi, à une expansion centrifuge; la dorsale est-pacifique a suivi le mouvement et forme aujourd'hui un arc bombé vers l'est. Dans les arcs océaniques extérieurs, l'expansion a provoqué la formation de dorsales transverses. Les failles transformantes montrent, dans les deux systèmes, des dispositions radiales. Les terrains de la côte W de l'Amérique du N ne peuvent provenir que d'une région située à l'Est de la dorsale est-pacifique dans sa position d'origine. Les continents s'éloigment et forme aujourd'hui un arc bombé vers l'est. Dans les arcs océaniques extérieurs, l'expansion a provoqué la forSous une telle »Néogée«, une nouvelle cellule de convection pourrait ensuite se développer. Ces phénomènes pourraient se dérouler dans un intervalle de quelques centaines de millions d'années, expliquant ainsi les cycles de Wilson dans l'histoire de la Terre.

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Geological evolution of the West Luzon Basin (South China Sea,Philippines)

Interpretation of deep 2-D multi-channel seismic data sheds insights into the geological evolution of the West Luzon Basin, Philippines. This basin is a sediment-filled trough that is located between the island of Luzon and the outer arc high of the west Luzon subduction zone. High-amplitude, low-frequency reflection bands mark the acoustic basement. The basement, at about 6 s (TWT), is dissected by normal faults with some of them being inverted in a later phase of deformation. The sedimentary successions, overlying the basement are stratified with partly chaotic structures and discontinuous reflectors. Five regional unconformities separate major stratigraphic units. Grid calculations of our seismic data reveal variations in the sedimentation pattern of the basin with a shift of the deposition centre from east to west and backwards during formation. A distinct bottom-simulating reflector is commonly observed. Because the northern boundary of the continental fragments to the South of the West Luzon Basin is unclear we speculate that the basin may be (partly) underlain by continental crust. The continental crust was affected by rifting prior to and during the opening of the South China Sea and the basin was overprinted at a later stage by a forearc structural setting when subduction was initiated.     

黄鳍鲷LDH同工酶的组织特异性研究

以黄鳍鲷为材料进行两方面研究:（1）用聚丙烯酰胺凝胶电泳方法，对其肌肉，心脏，肝脏，血清，玻璃体，晶状体，脑等组织器官进行LDH同工酶分析比较，结果表明，不同组织中LDH的同工酶谱带不相同，存在着组织特异性：（2）用聚丙烯酰胺等电聚焦电泳法对其肌肉，血清的LDH同工酶进行分离 ，结果得到12－15条电泳区带，等电点范围在pH为3．65－9．58之间。     

Quaternary geology of the Amazonian Lowland

The Quaternary history of the Amazon lowlands is characterized by deposition of sediments of Andean provenance and by the influences of changing sea levels. Areas well above the present water tables were not reached by Pleistocene high-water stages. These areas have been intensively weathered since the Tertiary, forming hard lateritic weathering horizons. These weathering horizons are best explained by the relatively constant, humid tropical climate throughout the Quaternary. In the western Amazonian Lowland, flood plains corresponding to the different Pleistocene sea-level heights were formed. During low sea level, erosion in the drainage areas increased and the water levels of the central Amazon River system were lowered. Valleys drowned and lakes formed in the lower reaches of rivers and creeks during high sea-level stages. These lakes (ria lakes) remained in the valleys with rivers having a low sediment load. Seismic profiling (3.5 kHz) in some of these lakes clearly showed deposits of the three last periods of Quaternary high sea-level stages.     

Dissolved aluminium and the silicon cycle in the Arctic Ocean

Concentrations of dissolved (0.2 µm filtered) aluminium (Al) have been determined for the first time in the Eurasian part of the Arctic Ocean over the entire water column during expedition ARK XXII/2 aboard R.V. Polarstern (2007). An unprecedented number of 666 samples was analysed for 44 stations along 5 ocean transects. Dissolved Al in surface layer water (SLW) was very low, close to 1 nM, with lowest SLW concentrations towards the Canadian part of the Arctic Ocean and higher values adjacent to and in the shelf seas. The low SLW concentrations indicate no or little influence from aeolian dust input. Dissolved Al showed a nutrient-type increase with depth up to 28 nM, but large differences existed between the different deep Arctic basins. The differences in concentrations of Al between water masses and basins could largely be related to the different origins of the water masses. In the SLW and intermediate water layers, Atlantic and Pacific inflows were of importance. Deep shelf convection appeared to influence the Al distribution in the deep Eurasian Basin. The Al distribution of the deep Makarov Basin provides evidence for Eurasian Basin water inflow into the deep Makarov Basin. A strong correlation between Al and Silicon (Si) was observed in all basins. This correlation and the nutrient-like profile indicate a strong biological influence on the cycling and distribution of Al. The biological influence can be direct by the incorporation of Al in biogenic silica, indirect by preferential scavenging of Al onto biogenic siliceous particles, or by a combination of both processes. From the slope of the overall Al–Si relationship in the intermediate water layer (AIDW; ~ 200–2000 m depth), an Al/Si ratio of 2.2 atoms Al per 1000 atoms Si was derived. This ratio is consistent with the range of previously reported Al/Si uptake ratio in biogenic opal frustules of diatoms. In the deepest waters (>2000 m depth) a steeper slope of the Al–Si relationship of 7.4 to 13 atoms Al per 1000 atoms Si likely results from entrainment of cold shelf water into the deep basins, carrying the signal of dissolution of terrigenous particles with a much higher Al:Si ratio of crustal abundance. Only a small enrichment with such crustal Al and Si component may readily account for the higher Al:Si slope in the deepest waters.     

Developing a building policy for the erosion zone: Solutions to some key (Dutch) questions

In those coastal communities where the most seaward strip of mainland consists of dunes, these dunes often serve as a flexible sea defence. In addition, this strip offers large potential for housing and commercial enterprises. Unfortunately, due to severe storm surges part of this strip (the erosion zone) is subject to erosion, and as a result of which any buildings or infrastructure located here, are destroyed. Therefore, as we will illustrate in this paper, a building policy for this zone should reflect a compromise between two opposite interests: exploitation of the existing potential and, prevention of an unacceptable high risk due to erosion. Accordingly, the authors have developed a framework for such a building policy on the basis of which the desirability of various different types of investments and the location within the erosion zone of such investments can be determined. The examples that are used to illustrate this framework in this paper are limited to experiences in The Netherlands as relevant data and experiences are available and relatively easy accessible here. Nevertheless, the approach as is described is generic and applicable worldwide suggesting that the discovered unused potential for exploitation is not just limited to The Netherlands.     

The effect of a topographic high on the morphological stability of a two-inlet bay system

The cross-sectional stability of two tidal inlets connecting the same back-barrier lagoon to the ocean is investigated. The condition for equilibrium is the cross-sectional area tidal prism relationship. In an earlier study [Van de Kreeke, J., 1990. Can multiple inlets be stable? Estuarine, Coastal and Shelf Science 30: 261–273.], using the same equilibrium condition, it was concluded that where two inlets connect the same basin to the ocean ultimately one inlet will close. One of the major assumptions in that study was that the water level in the basin fluctuated uniformly. In hindsight this assumption might be too restrictive. For example, in the Wadden Sea the back barrier lagoon consists of a series of basins, rather than one single basin, separated by topographic highs. These topographic highs limit but do not exclude the exchange of water between the sub-basins. For this reason in the present study, a topographic high in the form of a weir was added, separating the back-barrier lagoon in two sub-basins. The water level in the sub-basins, rather than in the back-barrier as a whole, is assumed to fluctuate uniformly. For this schematization the hydrodynamic equations are solved using a finite difference method. The results, together with the equilibrium condition, yield the equilibrium flow curve for each of the inlets. The intersections of the two equilibrium flow curves represent combinations of cross-sectional areas for which both inlets are in equilibrium. The stability of the equilibriums was investigated using a non-linear stability analysis resulting in a flow diagram. Calculations were carried out for different inlet and weir characteristics. Sinussoidal tides were the same for both inlets. The results show that for relatively large wetted cross-sectional areas over the topographic high, approaching the situation of a single basin, there are no combinations of inlet cross-sectional areas for which both inlets are in a stable equilibrium. This supports the conclusion in the earlier study. For relatively small wetted cross-sectional areas over the topographic high there is one set of stable equilibriums. In that case the two-inlet bay system approaches that of two single-inlet bay systems.