Salt varnishes
In the Austrian National Park Neusiedler See - Seewinkel in Burgenland there are around 40 small, salty lakes, the salt lakes of the Seewinkel, on an area of 25 km 2 . The largest and best known is the so-called Lange Lacke . Others are the pear tree lacquers , the foxhole lacquers and the darscho . Further salt biotopes exist in the northern Weinviertel near Zwingendorf and Baumgarten an der March .
Formation of the paints
The paints are a maximum of about 0.7 m deep and dry out regularly in summer. The original 150 salty lakes were created when large ice lenses left tub-shaped hollows in today's national park during the Ice Age . Today, many lacquers are surrounded by belts of reeds.
Sodium salts such as soda ( sodium carbonate ), in smaller quantities also Glauber's salt ( sodium sulfate ) and table salt ( sodium chloride ) as well as Epsom salt ( magnesium sulfate ) from the groundwater bloom on the surface in the summer dry period and form an alkaline storage horizon . This solonchak soil (Russian: salt soil) prevents the winter rainwater from seeping away.
The combination of long hours of sunshine, high temperatures in the annual mean value with low precipitation favors the capillary rise of the groundwater and thus the salt supply of the paints. If the water in the paint is colored brown by humic substances , it is called black water paint. In contrast, when the color is light gray due to clay colloids, one speaks of white water varnishes.
Significance and danger
As a very special biotope, the salt lakes offer a habitat for many rare animal and plant species. The lakes are also an important resting and resting place for migratory birds .
Years of drainage measures and the resulting lowering of the groundwater level interrupt the summer supply of salt to the paints, and the reservoir horizon dries up, becomes crumbly and permeable to water. The water becomes more acidic without the supply of salt from the groundwater, humus can form, whereby plants germinate and the lake area becomes desertified .
literature
- Milasowszky, Norbert: On the biology and ecology of two collembola species on an alkaline salt varnish in Seewinkel (Burgenland, Austria) - Proisotoma crassicauda (Tullberg, 1871) and Proisotoma schoetti . Vienna 1990, University of Vienna, dissertation.
- Andreas Glatz: Biology and population dynamics of two hemipterers : Heteroptera, Corixidae (Sigara concinna and Sigara lateralis) of an alkaline body of water (pear tree varnishes) in Seewinkel - Burgenland . Dissertation, University of Vienna, 1977
- Umweltbundesamt (Ed.): Salt habitats in Austria . (PDF; 3.8 MB) Vienna 2006. ISBN 3-85457-800-8 .