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A contiguous region of tidal flats about 448 km (280 miles) long and up to 21 km (13 miles) wide extends along the North Sea coasts of the Federal Republic of Germany, The Netherlands, and Denmark. This region is called the Wadden Sea. It is of enormous value as a cleansing site for the North Sea water, as a nursery for young fishes, and as a feeding grounds for nearly all Palearctic species of wading birds and waterfowl. The proximity of important shipping routes and ports is a permanent threat, especially to the German part of the region, which became a national park in 1986. The results of several field surveys, conducted from 1976 through 1986, revealed the necessity of an ecologically based sensitivity map for oil spill contingency planning. To evaluate properly the great variety of possible conditions resulting from the interrelationships of biotic and abiotic parameters, a system was developed to encompass such features, including the persistence of oil in the sediment, and the vulnerability and regenerative capability of a large proportion of the biota. Species of halophytes, mammals, fishes, birds, macrofauna, meiofauna, and microphytobenthos were evaluated to determine their physiological and ecological sensitivities to oil contamination. The evaluation was made considering autecological and synecological parameters. To test the applicability of the technique, a map was made of the littoral zone between the Weser and Elbe Rivers. The results were accepted by the West German organization for the control of oil spills at sea (ÖSK). Mapping will be continued under the direction of the Geesthacht Research Center until 1992. Eventually the project will cover the entire German part of the Wadden Sea through the financial support of the GKSS, the Umweltbundesamt (UBA), the ÖSK, and the national park authorities. A data processing system is being established by the GKSS so that the results can be used not only for oil spill control but also for the analysis of the ecosystem and to help the national park bureaus fulfill their obligations.

In January-February 1991, about 1 million m(3) of crude oil were released into the Arabian Gulf as a means of ecological warfare. A stretch of 644 km along the Saudi Arabian coast was heavily polluted over a width between a few meters and more than one kilometer. In four studies performed between March 1991 and April 1993 the state of representative areas of the affected coast was examined with the result that only minor changes were found in those oiled zones which are seldom inundated by the tides. Technical measures up to 1993 did not exceed the test level. A biological regeneration process is in progress which was not recognized as such in analyses of previous coastal oil pollution. Cyanobacterial mats, containing hydrocarbon-degrading bacteria, grow on oiled sediments which are regularly reached by tidal water. Shrinking and fracturing of the stable tar crusts starts a process of loosening and degrading of aged hydrocarbons.

Operational oil pollution surveillance has been performed in Germany for almost 30 years. Sophisticated state-of-the-art sensors are being used for frequent airborne surveillance, while satellite data are used as prewarning and additional information input on a routine basis. In parallel, basic research on the imaging of marine oil pollution by synthetic aperture radar (SAR) has been performed, and a basic understanding of the imaging of biogenic and anthropogenic marine surface films by active microwave sensors has been developed. In this paper, we provide an overview of the current operational surveillance system, and we give some historical background summarising some of the results of the research conducted during the past decades. Within this chapter, example images from pollution events are given for several sensors. The German coast's spatial and temporal vulnerability to oil pollution is quantified, and the use of dispersants in a highly vulnerable ecosystem such as the "Wadden Sea" is discussed.

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