Many of the Polish sandy coasts covered by several dune ridges are in danger, threatened by high wave storms and sea level rise. Some of the sandy coasts are accumulative. Accumulated on beach sand may cause growth and development of ridge. When upper beach at the front of the first dune is densely covered by plants sand may be fixed on beach. In this way on the upper beach may be built small hillocks or shadow dunes. It is important to know how fast a new dune ridge rises. This paper shows the importance of dune field formation on the upper beach in front of the foredune for new dunes accumulation. This field has possibilities to change in an initial dune ridge. Continuous aeolian accumulation of the sand on the dune field leads to the building of a new dune ridge. This process was observed on spit of Swina Gate Barrier on west Polish coast. The accumulation was forced by pioneer vegetation, which was covering hillocks and trapping transported sand from the beach. Also speeds and wind directions (measured in Swinoujscie) may cause bigger and faster accumulation. Author observed this process during five years on area of accumulative dune coast (the Swina Gate Barrier, west Polish coast). Before the beginning of the investigations, the upper beach in front of the foredune was covered by separated hillocks fixed by pioneer vegetation. After five years these hillocks became the new foredune ridge.
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The objective of the paper was to compare the utilization of wind power in the historical (mills) and the modern (power plants) landscape on the territory of the nowadays Czech Republic. The authors assessed the location, implementation and regionalization of these vertical structures and also their perception in the sense of local identity and the influence on the landscape character.
The distribution of algae and zooplankton on two transects across reed and Polygonum stands was observed. The algal community in the Polygonum stand had a mosaic structure mainly comprised of green algae plus desmids and diatoms (Pediastrum simplex, Scenedesmus acutus, Closterium ehrenbergii), whereas blue-green algae (cyanobacteria) Microcystis aeruginosa and Woronichinia naegeliana dominated from the reed boundary towards open waters. Some species, such as Euchlanis dilatata, prefer to be associated with plants, while others, like Synchaeta kitina, are more numerous in open waters. On a windward shore, wind at a velocity of 4 ? 5 m s-1 caused a slow back current from 8 to 18 m h-1. Movements of water were sometimes linear, but at times they developed in two dimensions.
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