MEPS 355:1-7 (2008)  -  doi:10.3354/meps07369

Importance of genetic diversity in eelgrass Zostera marina for its resilience to global warming

Anneli Ehlers1,2,*, Boris Worm1,3, Thorsten B. H. Reusch2,4

1Leibniz Institute for Marine Sciences, IfM-Geomar, Düsternbrooker Weg 20, 24105 Kiel, Germany
2Max-Planck-Institute for Limnology, August-Thienemann-Str. 2, 24306 Plön, Germany
3Biology Department, Dalhousie University, Halifax, Nova Scotia B3H 4J1, Canada
4Institute for Evolution and Biodiversity, University of Münster, Hüfferstr. 1, 48149 Münster, Germany

ABSTRACT: Effects of global warming on marine ecosystems are far less understood than they are in terrestrial environments. Macrophyte-based coastal ecosystems are particularly vulnerable to global warming, because they often lack species redundancy. We tested whether summer heat waves have negative effects on an ecologically important ecosystem engineer, the eelgrass Zostera marina L., and whether high genotypic diversity may provide resilience in the face of climatic extremes. In a mesocosm experiment, we manipulated genotypic diversity of eelgrass patches fully crossed with water temperature (control vs. temperature stress) over 5 mo. We found a strong negative effect of warming and a positive effect of genotypic diversity on shoot densities of eelgrass. These results suggest that eelgrass meadows and associated ecosystem services will be negatively affected by predicted increases in summer temperature extremes. Genotypic diversity may provide critical response diversity for maintaining seagrass ecosystem functioning, and for adaptation to environmental change.


KEY WORDS: Climate change · Ocean warming · Coastal ecosystem · Genotypic diversity · Intraspecific variation · Resilience · Zostera marina


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Cite this article as: Ehlers A, Worm B, Reusch TBH (2008) Importance of genetic diversity in eelgrass Zostera marina for its resilience to global warming. Mar Ecol Prog Ser 355:1-7

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