The "Helgoland roads" time seriesAlfred Wegener Institute for Polar and Marine Research
A single hot summer is not necessarily a sign of a longterm trend, nor is a single large algal bloom.
Many natural phenomena occur by chance or are related to cyclical events such as solar activity. This is why long-term measurements are crucial for distinguishing long-term changes from short-term fluctuations. One of the most important long-term data sets is being collected by the Alfred Wegener Institute (AWI) on the North Sea island of Helgoland. Since 1962, a team of AWI researchers has sampled the Helgoland Roads time series station off the island’s coast on a work-daily basis to measure water temperature, salinity, water transparency and nutrient levels. The plankton that serve as food for marine fauna is also sampled. “With these long-term measurements, we have solid proof that the average temperature of the waters at Helgoland Roads have warmed by 1.7 degrees Celsius compared to the 1960s,” says Dr. Alexandra Kraberg, who is responsible for the time series jointly with Professor Karen Wiltshire. At the same time, the water has become clearer and more saline. Furthermore, over time, the biologists have observed many new species of plankton. Since some of these species are considered warmth-loving, it is tempting to regard them as indicators of ongoing global warming. By combining the Helgoland Roads time series data with laboratory tests and mesocosm experiments, the scientists are investigating whether these new species can become a permanent component of the local plankton community and, if so, whether these changes might have implications for future food web interactions. However, the Helgoland data are not only used by AWI scientists but also by scientists around the world. In addition, they provide a reliable basis for the development of science-based adaptation strategies by public authorities.
Media about the subject
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