142 publications from this institution
Sedimentological and morphological changes on the upper and lower shoreface during relatively stable sea-level highstand conditions have been investigated in the Pomeranian Bight, southern Baltic Sea, at time scales ranging from storm events to millennia. In order to cover that variety of time scales, different methods have been applied. Seasonal variations in the morphology of the upper shoreface were measured accurately using the tracer stick method. The ratio of breaking waves and energy dissipation due to wave breaking are the main forces controlling redeposition on the upper shoreface with the depth of disturbance up to three times the net change. The impact of single storm events can be observed from sidescan sonar mosaics to remain on the decadal scale. Aerial photographs covering the upper shoreface show that the location of gates, channel-like systems where water masses move offshore created during storm events, also remain stable over decades. Sedimentological and geomorphological variations and changes on the lower shoreface are only measurable on the century to millennium scale because the main driving forces are long-lasting processes like sea-level fluctuations or neotectonics. Data on these scales have much more uncertainty in their relationship to forcing functions than data at shorter time scales. Because the effects of coastal processes active on different time scales can interact, comprehensive understanding of large-scale coastal behavior requires investigations from short events to long-term processes.
The Wadden Sea forms the interface between the open North Sea and the mainland, extending over a distance of about 450 km from Denmark via Germany to the Netherlands and reaching a width of up to 25 km along the German coast. For the German part of the Baltic Sea coastline, Jensen and Mudersbach studied mean, low and high water levels in comparison to the German North Sea coast using the normalized arithmetic mean of the four gauges at Travemunde, Warnemunde, Wismar and Sassnitz. Coastal groins Coastal groins represent one of the oldest coastal protection structures in Germany and still represent an important part of coastal protection schemes. In the German "Recommendation for Shore Protection Measures" the latter are named 'stream groins'. Wooden pile groins using various designs were also established on German North Sea islands, constructed both as permeable and impermeable groins.
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Grain-size distribution of sea floor deposits of Nõva Bay and Keibu Bay, northwestern Estonia, is discussed.Based on grain-size statistics, the lateral and vertical distribution of different types of bottom sediments is shown and compared for the two bays.The bottom deposits consist mostly of sand (80-100%).The proportion of silt and gravel is considerably smaller: up to 3% in Nõva Bay and up to 7% in Keibu Bay.In Nõva Bay medium sand predominates.Grain-size distribution of deposits is rather uniform and an obvious correlation exists between the occurrence of different fractions and the water depth.In Keibu Bay sand of different grain size prevails.Along the boundary between the mouths of the bays and the open sea, a belt of coarse sand runs parallel with the shoreline.Beyond this belt silt and clay are predominant.
The coastal development of the Rio Aqu area (Rio Grande do Norte, Brazil) and the response of the river mouth to the Holocene sea level rise were reconstructed from seismostratigraphy. A sharply defined stratigraphic boundary between the Pleistocene and Holocene deposits was recognised. The seismic data reveal that, during sea level lowstand, a valley up to 9 km wide was cut into the Pleistocene deposits of the shelf platform. This valley extends perpendicular to the shoreline and is preserved in the recent morphology. It narrows at similar to 20 kin offshore to a I km wide channel, which then widens to its former size a few hundred meters further offshore. Several incised valleys and cut and fill structures up to 2500 in wide and 12 in deep were observed in the Pleistocene deposits. These extend to 45 in below sea level, and indicate that the ancient Rio Aqu meandered. A sediment sequence with sigmoidal structures increases in thickness offshore to 12 in, is composed of reworked material, and is interpreted as an embankment. A tilted block composed of more solid material was identified over a distance of at least 800 in. Holocene sediments thin out above this block, indicating postglacial neotectonics in the area.
Submarine hard bottoms (e.g., boulders, outcropping strata) are of particular ecological importance. They were investigated in the Exclusive Economic Zones (EEZ) of the German North Sea and the Baltic Sea, using high-resolution seafloor imaging techniques (i.e.,...
