title: Seasonal Variations in Surface Metabolite Composition of Fucus vesiculosus and Fucus serratus from the Baltic Sea.
abstract: Perennial macroalgae within the genus Fucus are known to exude metabolites through their outer thallus surface. Some of these metabolites have pro- and/or antifouling properties. Seasonal fluctuations of natural fouling pressure and chemical fouling control strength against micro- and macrofoulers have previously been observed in Fucus, suggesting that control strength varies with threat. To date, a study on the seasonal composition of surface associated metabolites, responsible for much of the fouling control, has not been done. We sampled individuals of the two co-occurring species F. vesiculosus and F. serratus at monthly intervals (six per species and month) during a one-year field study. We analysed the chemical composition of surface associated metabolites of both Fucus species by means of gas chromatography-mass spectrometry (GC-MS) to describe temporal patterns in chemical surface composition. Additionally, we correlated abiotic and biotic parameters recorded monthly within the sampled habitat with the variation in the chemical surface landscape of Fucus. Our study revealed that the chemical surface composition of both Fucus species exhibits substantial seasonal differences between spring/summer and autumn/winter months. Light and temperature explained most of the seasonal variability in surface metabolite composition of both Fucus species. A strong summerly up-regulation of eighteen saccharides and two hydroxy acids in F. vesiculosus as well as of four fatty acids and two saccharides in F. serratus was observed. We discuss how these up-regulated molecules may have a complex effect on associated microfoulers, both promoting or decreasing fouling depending on metabolite and bacterial identity. These seasonal shifts in the surface metabolome seem to exert a compound control of density and composition of the Fucus associated biofilm.
authors.affiliation: Department of Marine Ecology, Division of Benthic Ecology, Helmholtz Centre for Ocean Research Kiel GEOMAR, Kiel, Germany.
authors.forename: Esther
authors.initials: E
authors.lastname: Rickert
authors.affiliation: Department of Marine Ecology, Division of Benthic Ecology, Helmholtz Centre for Ocean Research Kiel GEOMAR, Kiel, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Wahl
authors.affiliation: Institute for Ecosystem Research, Kiel University, Kiel, Germany.
authors.forename: Heike
authors.initials: H
authors.lastname: Link
authors.affiliation: Institute for Inorganic and Analytical Chemistry, Department for Bioorganic Analytics, Friedrich Schiller University Jena, Jena, Germany.
authors.forename: Hannes
authors.initials: H
authors.lastname: Richter
authors.affiliation: Institute for Inorganic and Analytical Chemistry, Department for Bioorganic Analytics, Friedrich Schiller University Jena, Jena, Germany.
authors.forename: Georg
authors.initials: G
authors.lastname: Pohnert
mesh_terms: D018441:Biofilms; D017753:Ecosystem; D005227:Fatty Acids / Q000737:chemistry; D044645:Fucus / Q000378:metabolism*; D008401:Gas Chromatography-Mass Spectrometry; D006880:Hydroxy Acids / Q000737:chemistry; D008027:Light; D016014:Linear Models; D009792:Oceans and Seas; D011134:Polysaccharides / Q000737:chemistry; D012621:Seasons; D012624:Seaweed / Q000378:metabolism; D013696:Temperature; D015854:Up-Regulation
chemical_list: D005227:Fatty Acids; D006880:Hydroxy Acids; D011134:Polysaccharides