HR: 16:20h
AN: OS34B-01 INVITED     [Abstracts]
TI: Long-Term Ecological Change in the Wadden Sea
AU: * van Beusekom, j
EM: justus.van.beusekom@awi.de
AF: Alfred-Wegener-Institute for Polar- and Marine Research/ Wadden Sea Station Sylt, Hafenstrasse 43, List/Sylt, D-25992, Germany
AB: The North Sea (eastern Atlantic, Europe) is among the most intensely used coastal seas. A large part of the eastern coastal region is covered by the Wadden Sea, a shallow tidal sea protected from the North Sea by barrier islands. It is characterized by a high productivity and harbors a rich sea live. It is also under strong human pressure. A large part of the continental run-off passes along the Wadden Sea. Coastal protection measures have squeezed the Wadden Sea into a narrow zone. In this presentation an overview of ecological change in the Wadden Sea will be presented. Focus will be on eutrophication, but other aspects of ecological change will be addressed. It will be shown, that after reaching a maximum during the mid 1980's riverine nutrient loads are now decreasing. As a response, coastal eutrophication is slowly decreasing. This is documented by several nutrient and chlorophyll time series in the Wadden Sea. Possibly, a recent increase in seagrass is also related to the decreased nutrient loads. In addition to eutrophication, climate change has a large impact on the long term dynamics: In the Northern Wadden Sea, warmer winters lead to a general decrease in the spring bloom and a recent decrease in mean autumn wind speed has lead to a longer phytoplankton growth season. Whereas the present de-eutrophication suggests the potential of the area to return to previous lower production levels, other changes e.g. caused by introduced species have a permanent character. Scenarios will be discussed how the Wadden Sea may respond to future coastal change.
DE: 4805 Biogeochemical cycles, processes, and modeling (0412, 0414, 0793, 1615, 4912)
SC: Ocean Sciences [OS]
MN: 2007 Joint Assembly