Über einige Strukturzüge der Appalachen

Ohne Zusammenfassung     

Dealing with the problem of eutrophication in the Adriatic Basin: the institutional framework and policies

The process of eutrophication in the Adriatic Sea Basin has emerged over recent decades as a problem that demands special consideration and treatment; one of the most important reasons is the damage to the economy due to its undesired effects.Scientific knowledge concerning this process, while not exhaustive, is sufficient as a basis for directing action. But the experience acquired to date demonstrates that scientific knowledge alone cannot steer practical action, assuring the use of all existing (limited) knowledge to define the best practicable actions in a given time and place. In other terms, the institutional framework has not been able to use this knowledge for improving the environmental state of the Basin.To overcome this unsatisfactory situation, a different definition of the problem is proposed, as well as a different way for designing suitable solutions.     

Cenozoic oceanic sedimentation rates: How good are the data?

The distribution of core material gathered by the Deep Sea Drilling Project (DSDP) is compared with known data concerning the distribution of the floors of the oceans with respect to latitude, water depth, physiographic province and age. Also patterns of sedimentation in Middle Miocene, Early Oligocene and Middle Eocene times, plotted on paleogeographic reconstructions, are shown to be readily interpretable in terms of our present understanding of the factors controlling oceanic sedimentation. The general conclusion is the DSDP core material is representative of the geologic record of the ocean floor but that considerable care must be exercised in any quantitative interpretation of the drilling results.     

The effects of oil exploration and production in the northern north sea: Part 1–The levels of hydrocarbons in water and sediments in selected areas, 1978–1981

In the light of increasing oil exploration and production in the northern North Sea, the Brent, Beryl and Forties oil fields, representing three different types of operation, and a number of stations between the Forties field and the Firth of Forth, were sampled to determine the levels of total (by fluorescence), alkane (by glass capillary gas chromatography) and aromatic (by gas chromatography-mass spectrometry) hydrocarbons in water and sediments. Close to the Beryl platform, where diesel-washed drill cuttings have been dumped, there was an accumulation of petrogenic hydrocarbons in the sediment, resulting in a build up of certain aryl hydrocarbons, notably the dibenzthiophenes and 3- and 4-ring aromatic compounds. In all the sediment samples analysed for aromatic hydrocarbons, relatively large amounts of 5- and 6-ring compounds were found in areas expected to be free of pollution, as well as from areas around oil platforms and from the Firth of Forth. Their source is likely to be windborne combustion products.     

Particulate barium fluxes on the continental margin: a study from the Alboran Sea (Western Mediterranean)

Particulate biogenic barium (bio-Ba) fluxes obtained from three instrumented arrays moored in the Alboran Sea, the westernmost basin in the Mediterranean Sea, are presented in this study. The mooring lines were deployed over almost 1 year, from July 1997 to May 1998, and were equipped with sediment traps at 500–700 m depth, 1000–1200 m depth and 30 m above the seafloor (1000–2200 m). The results obtained support the growing body of evidence that the relationship between particulate bio-Ba and Corg throughout the water column in margin systems is clearly different from this relation in the open ocean. In the Alboran Sea, the annual averaged bio-Ba fluxes range from 0.39 to 1.07 μmol m⁻² day⁻¹, with mean concentrations of 1.31–1.69 μmol g⁻¹ and bio-Ba/Corg ratios lower than in the open ocean. The low bio-Ba values obtained also indicate that calculating bio-Ba is extremely sensitive to the detrital Ba/Al ratio of each sample. The lithogenic Ba fraction in the Alboran Sea continental margin area contributes between 24% and 85% of the total Ba. Increased bio-Ba export efficiency was observed after periods of high primary productivity and suggests that the processes limiting the bio-Ba formation in the study area relate to settling dynamics of organic matter aggregates. Furthermore, the ballasting effect of the abundant lithogenic and carbonate particles may limit decomposition of organic matter aggregates and enhance the transfer of particles rich in Corg and relatively poor in bio-Ba to the deep seafloor. Lateral input of freshly sedimented biogenic material, including particulate bio-Ba, has been observed on the lower continental slope in the western Alboran Sea. These observations emphasize that the use of the bio-Ba as a proxy of export productivity from the surface ocean must be used cautiously in highly dynamic environments such as those in the Alboran Sea.