Climate control on the long-term anomalous changes of zooplankton communities in the Northwestern Mediterranean

Authors

  • JUAN CARLOS MOLINERO,

    1. Ecosystem Complexity Research Group, Station Marine, Université des Sciences et Technologies de Lille, CNRS – UMR 8013 ELICO, 28 avenue Foch, BP 80, F-62930 Wimereux, France,
    2. Leibniz-Institut für Meereswissenschaften, IFM-GEOMAR, Marine Ecology/Experimental Ecology, Düsternbrooker Weg 20, 24105 Kiel, Germany,
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  • FRÉDÉRIC IBANEZ,

    1. Laboratoire d'Océanographie de Villefranche (LOV), Station Zoologique-BP 28, 06234 Villefranche-sur-mer, France,
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  • SAMI SOUISSI,

    1. Ecosystem Complexity Research Group, Station Marine, Université des Sciences et Technologies de Lille, CNRS – UMR 8013 ELICO, 28 avenue Foch, BP 80, F-62930 Wimereux, France,
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  • EMMANUELLE BUECHER,

    1. Zoology Department, University of the Western Cape, Private Bag X17, Bellville 7535, South Africa
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  • SERGE DALLOT,

    1. Laboratoire d'Océanographie de Villefranche (LOV), Station Zoologique-BP 28, 06234 Villefranche-sur-mer, France,
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  • PAUL NIVAL

    1. Laboratoire d'Océanographie de Villefranche (LOV), Station Zoologique-BP 28, 06234 Villefranche-sur-mer, France,
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Juan Carlos Molinero, Ecosystem Complexity Research Group, Station Marine, Université des Sciences et Technologies de Lille, CNRS – UMR 8013 ELICO, 28 avenue Foch, BP 80, F-62930 Wimereux, France, e-mail: jmolinero@ifm-geomar.de

Abstract

In marine ecosystems, pelagic copepods, chaetognaths and jellyfish play a key role in matter and energy flow. While copepods support most food webs and the biological pump of carbon into the deep ocean, chaetognaths and jellyfish may affect the strength of the top-down control upon plankton communities. In this study, we show that the main events in the long-term variability of these functional groups in the Northwestern Mediterranean were tightly linked to changes of climate forcing of the North Atlantic sector. Large-scale climate forcing has altered the pelagic food-web dynamics through changes in biological interactions, competition and predation, leading to substantial changes manifested as bursts or collapses in zooplankton populations, and consequently to a major change ca. 1987. These events become more frequent in the 1980s and the early 1990s in the studied zooplankton functional groups suggesting a shift in the functioning of the pelagic ecosystem. The environmental modifications and the results reported here are therefore, indicators of a regime change pointing to a more regeneration-dominated system in the study area. We suggest a chain of mechanisms, whereby climate variation has modified the long-term dynamics of pelagic copepods, chaetognaths and jellyfish in the Ligurian Sea.

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