Ocean Dynamics

, 58:169 | Cite as

A statistical analysis of climate variability and ecosystem response in the German Bight

  • Merja H. Schlüter
  • Agostino Merico
  • Karen H. Wiltshire
  • Wulf Greve
  • Hans von Storch


We compiled homogeneous long-term time series comprising 39 variables representing the German Bight and for the period 1975–2004. A diverse set of variables was selected to cover multiple trophic levels and different environmental forcing thus to examine long-term changes in this coastal region. Previous studies have hypothesised the presence of regime shifts in observations extending over the entire North Sea. Focusing on a smaller spatial scale, and closer to the coast, we investigated the major modes of variability in the compiled time series using principal component analysis. The results obtained confirm a previously identified regime shift in the North Sea in 1987/1988 and suggest that the German Bight is dominantly characterised by long-term modes of variability. In the German Bight, the shift of 1987/1988 is driven primarily by temperature, Gulf Stream index, frost days and Secchi depth. Changes in some of the ecosystem variables (plankton and fish) appear to be related to changes in these driving variables. In particular, we documented strong positive correlations between the long-term trend showed by the first principal component and herring, Noctiluca scintillans, and, to a lesser extent, Pleurobrachia pileus. Two gadoids, namely cod and saithe, showed negative correlations with the observed long-term mode of variability. Changes in the sum of five small calanoid copepods were, however, less marked. Phosphate and ammonium exhibited a decreasing trend over the last 30 years. Diatoms and Calanus helgolandicus did not show evidence of changes in concert to this trend. Specific analyses of the data divided into three different subsets (biological, climatic and chemical) characterise the climate of the German Bight as highly dynamic also on short timescales (a few years) as compared to much smoother biological and chemical components. The dynamic regime of the German Bight taken together with a low correlation between the major mode of variability and phytoplankton and zooplankton data suggests that the lower trophic levels of this ecosystem are remarkably resilient.


Climate change German Bight Principal component analysis Marine ecosystem Long-term trend Helgoland Roads 



The authors would like to thank Kai Wirtz for fruitful comments. We also thank Eduardo Zorita for providing his software for CCA and for his constructive suggestions. We thank the German Weather Service (DWD) for providing the relevant meteorological, the BSH for the gridded SST and ICES for the fish data. We thank the crews of the research vessels ‘Aade’ and ‘Ellenbogen’ of the BAH, as well as Silvia Janisch and Peter Mangelsdorf for their unfailing provision of samples and data. This study was in part funded by the Priority programme AQUASHIFT of the German Science Foundation (DFG). We like to thank two anonymous referees for comments that helped to improve the manuscript.


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Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  • Merja H. Schlüter
    • 1
  • Agostino Merico
    • 1
  • Karen H. Wiltshire
    • 2
  • Wulf Greve
    • 3
  • Hans von Storch
    • 1
  1. 1.Institute of Coastal ResearchGKSS Research CenterGeesthachtGermany
  2. 2.Biologische Anstalt HelgolandAlfred Wegener Institute for Polar and Marine ResearchHelgolandGermany
  3. 3.German Centre for Marine Biodiversity Research (Senckenberg Research Insti- tute)HamburgGermany

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