Parallel long-term trends across four marine trophic levels and weather.
The temporal changes revealed by long-term studies of components of the marine ecosysteml-4 are of particular relevance given the growing concern about trace-gas-induced climatic change5 . The extent to which they reflect the signal of weather relates directly to the validity of using them for detecting climatic change6-8. We report here on remarkable similarities in trends among four series of marine data and one of climatic data. The series overlap in time over 33 years (1955-1987), and in space over the northwestern quadrant of the North Sea. They relate to the abundances of phytoplankton, zooplankton and herring (Clupea harengus), to the breeding performance of the kittiwake gull (Rissa tridactyla), and to variations in weather pattern. The mechanisms behind the parallelism in trends remain unclear; a major challenge is to construct food-web models capable of reproducing the pattern and thereby of use in interpreting and detecting global climatic change.