Wadden Sea

This article deals with the general concept of the Wadden Sea. See Wadden Sea (North Sea) for more information about the Wadden Sea in the German Bight.

Wadden seas (derived from mud flats ) are certain coastal areas of a sea that are strongly influenced by the tides .

French Wadden Sea at Mont Saint-Michel at low tide

Large areas of a Wadden Sea regularly dry out twice a day during the low tide period (ebb) and are flooded during the high tide period (high tide). The areas that fall dry at low tide are called tidal flats. The term Wadden Sea is only used on flat coasts with sand or mud flats. The channels through which the water runs preferentially out of the tidal flats at low tide and through which the water flows preferentially into the tidal flats at high tide are called tidal creeks , the largest of which are called sea ​​muds .

Occurrence

Low water in the Wadden Sea of ​​the North Sea near Sylt

Wadden seas are found in many parts of the world in the temperate zones . In the tropical zones , such coastal areas are mostly overgrown with mangroves (tidal forests ).

features

Aerial view of a creek with side arms at low tide in the Lower Saxony Wadden Sea.

In a Wadden Sea, the bottom has only a slight gradient, with the difference in height generally being less than one meter over a length of one kilometer. At the same time, the difference in water level between high water and low water is at least two meters so that a sufficiently large area falls dry.

In the area of river mouths , fine-grained material and suspended matter, which were previously washed into the rivers in relatively low-rainfall, flat areas, are carried into the sea by the currents. Land-based winds also feed this material into the Wadden Sea, which then becomes part of the tidal sediment.

The Wadden Sea is divided into three zones. The sublittoral area is below the mean low water level, which also includes the creeks . The supralitoral area lies above the mean high water level and is only flooded when the tides are particularly high. If there is no human management, salt marshes are usually created here . The actual watt, i.e. That is, the areas that are below the water level at high tide and above the water level at low tide are the eulittoral area.

Offshore islands and sandbanks often form a protection against the surf of the open sea and slow down the seaward ebb current.

Flora and fauna

A Wadden Sea offers a special, sometimes extreme habitat . Many animals and plants live exclusively in the respective Wadden Sea in which they are settled and have adapted to the prevailing conditions there. In addition, a Wadden Sea is often an important resting area for migratory birds . In addition, the Wadden Sea provides a habitat for lugworms and many types of mussels . Seals rest on higher lying areas that fall completely dry at low tide, so-called mud flats . The only briefly (at about spring tides dry falling) surfaces move seaweeds , the only temporarily flooded land plants such as Salicornia on. There are also many unique plants that only take root and stabilize the sandy, loose soil of the coastal dunes .

environmental issues

The Wadden Sea habitat is very sensitive and sensitive to external influences, some of which are of human origin. This includes embankments and drainage of supralitorial areas of the Wadden Sea, the entry of environmental toxins from industry and excessive amounts of nutrients from agriculture as well as pollution from overfishing , traffic and tourism.

That is why there are initiatives around the world to protect the Wadden Sea, which are already showing signs of international cooperation. For example, the protection of the Wadden Sea the North Sea to coordinate better in 1987 by the Netherlands, Germany and Denmark, the Common Wadden Sea Secretariat (CWSS) or Wadden Sea Secretariat established.

Wadden seas worldwide

The Wash on the English North Sea coast at low water as seen from Heacham in Norfolk

View over the mudflats of Morecambe Bay on the English side of the Irish Sea

• in Europe
  • at the North Sea
    • the Wadden Sea in the German Bight :
      • the Hamburg Wadden Sea National Park
      • the Lower Saxony Wadden Sea National Park
      • the Schleswig-Holstein Wadden Sea National Park
      • the national natural monument Waddenzee in the Netherlands
      • the Vadehavet National Park in Denmark
    • on the English North Sea coast
      • the Wadden Sea around the English island of Lindisfarne in Northumberland
      • The Wash Bay in Lincolnshire and East Anglia, which is largely dry at low tide
      • the Thames estuary
  • on the English Channel
    • the stretch of coast at Mont-Saint-Michel with a monastery built on a granite rock in the middle of the Wadden Sea
    • the Romney Marsh on the Kent and East Sussex coast ,
  • on the Irish Sea
    • the Morecambe Bay (England)
    • the Bridgwater Bay (England)
  • at the Atlantic Coast
    • the Baie de Bourgneuf with the island of Noirmoutier (France)

• in Africa
  • on the North African Atlantic coast
    • the Banc d'Arguin National Park in Mauritania

View over Daniel's Flats on the northwest edge of Chignecto Bay, New Brunswick, Canada

• in North America
  • at the Atlantic Coast
    • the Minas Basin (approx. 400 km²) and the Chignecto Bay , the two main arms of the upper Bay of Fundy (Canada),
    • the Cape Cod Bay (USA)
  • on the Pacific coast
    • Parts of the San Francisco Bay (USA)

• in South America
  • Marshlands on both sides of the Essequibo estuary

• in East Asia
  • the Korean Yellow Sea Coast ; its largest connected mudflat area, Saemangeum (approx. 400 km²), was diked in 2006.
  • The Kuril Wadden Sea
  • the Chongming Dongtan nature reserve near Shanghai (China)

Web links

Wiktionary: Wadden Sea  - explanations of meanings, origins of words, synonyms, translations

literature

• Klaus Janke, Bruno P. Kremer: The watt - habitat, animals and plants . Franckh, Stuttgart 1990, ISBN 3-440-06035-7 .
• Waddenacademy, Common Waddensea Secretariart (CWSS) (Ed.): The Wadden Sea Region. World-class cultural landscape. (German translation of the brochure The Wadden Sea Region - A World Class Cultural Landscape (PDF; 15.7 MB), ISBN 8787036827 by Frank Petzold and Manfred Vollmer).
• Berndt Heydemann, J. Müller-Karch: Wadden Sea: Significance-Endangerment-Protection . Deutscher Naturschutzring, 1981, ISBN 3-923-458-00-2 , hdl : 10013 / epic.44288.d001 (pdf; 25 MB).

Notes and individual references

1. ↑ Petra Witez: Final report on the research project MTK 0608 (03 KIS 3160): Programs for the long-term conservation of the Wadden Sea - Prowatt. Edited by the Federal Ministry for Education and Research, Laboe 2002, p. 6.
2. ^ Karsten Reise, Christiane Gätje: Introduction. In: Karsten Reise, Christiane Gätje: Wadden Sea Ecosystem: Exchange, transport and material conversion processes. Springer-Verlag, Berlin, Heidelberg 1998, ISBN 3-540-63018-X , pp. 1-24.
3. ^ Bay of Fundy Ecosystem Partnership
4. ↑ Russia from above (3/3). Retrieved May 29, 2020 .