MEPS 239:1-10 (2002)  -  doi:10.3354/meps239001

Ocean climate anomalies and the ecology of the North Sea

Martin Edwards1,*, Gregory Beaugrand1,2, Philip C. Reid1, Ashley A. Rowden3, Malcolm B. Jones4

1Sir Alister Hardy Foundation for Ocean Science, The Laboratory, Citadel Hill, Plymouth PL1 2PB, United Kingdom
2Observatoire des sciences de l¹univers, Laboratoire d¹oceanographie biologique et d¹ecologie du plancton marin, BP 28, 06234 Villefranche-sur-Mer cedex, France
3Marine Biodiversity Group, National Institute of Water and Atmospheric Research (NIWA), Geta Point, PO Box 14-901, Wellington, New Zealand
4Department of Biological Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA, United Kingdom

ABSTRACT: Long-term changes in the plankton of the North Sea are investigated using data from the continuous plankton recorder (CPR) survey. During the last 4 decades, there appears to have been 2 large anomalous periods within the plankton data set, one that occurred in the late 1970s and the other in the late 1980s. These anomalous periods seem to be largely synchronous with unusual ocean climate conditions that have occurred episodically over a timescale of decades. The unusual ocean climate conditions prevailing at these 2 time periods appear to contain important hydrographical elements that involve oceanic incursions into the North Sea. This paper, using data from the CPR survey and providing evidence from other studies, focuses on the relationship between the long-term changes in the biology of the North Sea and these 2 exceptional hydro-climatic events. Here, we suggest that while atmospheric variability and associated changes in regional temperatures have a dominant effect on the marine environment, oceanic influences on the ecology of a semi-closed environment such as the North Sea may have been underestimated in the past.


KEY WORDS: North Sea · Plankton communities · Long-term trends · Continuous plankton recorder · Great salinity anomaly · Ocean climate


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