Vera Winde

Effects of warming and acidification on a benthic community in the Baltic Sea - Kiel Benthocosms

Station Biologique de Roscoff, Sorbonne Universités, Université Pierre et Marie Curie, CNRS, Roscoff 29688, France; Institut de Systématique, Evolution, Biodiversité, UMR 7205CNRS-EPHE-MNHN-UPMC, Muséum National d’Histoire Naturelle, Paris 75231, France; Station Biologique de Roscoff, CNRS, Sorbonne Universités, Université Pierre et Marie Curie, Roscoff 29688, France and Station Biologique de Roscoff, CNRS, Sorbonne Universités, Université Pierre et Marie Curie, Roscoff 29688, FranceEarly life-stage of the bladderwrack Fucus vesiculosus is highly influenced by the climate change factors temperature, CO2 and eutrophication. Intraspecific genetic diversity of Baltic Fucus vesiculosus populations is low, compared to e.g. Atlantic populations, which may limit their potential for adaptation. To assess the role of intraspecific genetic diversity on the tolerance towards environmental change we manipulated their diversity: Plots with full-sibling Keynote and Oral Papers 106 Downloaded by [University of Kiel] at 02:13 22 September 2015 groups of Fucus germlings each originating from one parental pair represents the low diversity level, whereas plots with sibling groups from multiple parental pairs represent the high diversity level. Climate change was simulated according to the year 2100 in the near-natural scenario Kiel Benthocosms by maintaining the environmental fluctuations of the Baltic Sea and adding 5°C warming, 600 μatm pCO2 and doubling the nutrient concentrations. Germlings responded to warming with higher mortality and enhanced growth rates. High pCO2 concentrations increased growth due to a fertilisation effect. Nonphotochemical quenching was lower under warmed than ambient temperatures. A positive co-tolerance among sibling groups towards warming and acidification indicates the possible attenuation in presence of the multiple factors. Considerable differences among sibling group performance indicate a higher adaptive potential for genetically diverse populations. The high diversity levels also showed higher survival, indicating possible facilitation processes among genotypes. Microsatellite genotyping is in progress for revealing whether and how selection processes took place in high diversity levels. We conclude that impacts on early life-stage bladderwrack depend on the combination of stressors and season and that genetic variation is crucial for local adaptation to climate change stress