The Sunday Challenge = Transition
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An excellent example of constant transition is the Wadden Sea (Dutch: Waddenzee, German: Wattenmeer), an intertidal zone in the southeastern part of the North Sea. It lies between the coast of northwestern continental Europe and the range of Frisian Islands, forming a shallow body of water with tidal flats and wetlands. It is rich in biological diversity

The Wadden Sea is famous for its rich flora and fauna, especially birds. Wadden Sea is an important habitat for two species of seals, harbor and grey seals. In 2009 it is inscribed on UNESCO's World Heritage List.
You can see numerous birds and seals on the mud flats in this image. Try the larger view.

The word wad is Dutch for "mud flat". The area is typified by extensive tidal mud flats, deeper tidal trenches (tidal creeks) and the islands that are contained within this, a region continually contested by land and sea.

The islands are marked by dunes and wide, sandy beaches towards the North Sea and a low, tidal coast towards the Wadden Sea. The impact of waves and currents, carrying away sediments, is slowly changing the layout of the islands. Some islands have moved eastwards through the centuries, having lost land on one side and grown on the other.