title: Microspatial variability in community structure and photophysiology of calcified macroalgal microbiomes revealed by coupling of hyperspectral and high-resolution fluorescence imaging.
abstract: Calcifying coralline macroalgae provide biogenic habitats colonised by epiphytic microalgae that contribute significantly to community productivity. Georeferenced hyperspectral and high-resolution fluorescence imaging were coupled to microspatially mapped community composition and relative biomass of macroalgal host and epiphyte microalgal groups, and their weighted contributions to productivity within host fronds of Corallina officinalis on upper and lower zones of a rocky shore were determined. Lower shore epiphytes were dominated by filamentous diatoms (Bacillariophyta), confined to the apex of the frond structure, which were low light acclimated but retained a high capacity for photoprotective down regulation and contributed up to 51% of total community productivity. Upper shore epiphytes were dominated by green algae (Chlorophyta) and single-celled diatoms (principally Cocconeis spp.), which were high light acclimated but present at far lower relative biomass and contributed negligibly to productivity. The host, C. officinalis was the main primary producer. Variation in light environment resulting from differences in shore height and shading within the host macroalga, likely play a large role in determining patterns in epiphyte community structure, biomass and productivity observed. Additionally, microspatial gradients in photophysiological parameters along the host macroalga likely resulted from age-dependent variation in pigments as well as the gradient in light environment.
authors.affiliation: School of Earth and Ocean Sciences, Cardiff University, Cardiff, Glamorgan, CF10 3AT, UK.
authors.forename: R G
authors.initials: RG
authors.lastname: Perkins
authors.affiliation: School of Earth and Ocean Sciences, Cardiff University, Cardiff, Glamorgan, CF10 3AT, UK.|Natural History Museum, Department of Life Sciences, Cromwell Road, London SW7 5BD, UK.
authors.forename: C J
authors.initials: CJ
authors.lastname: Williamson
authors.affiliation: Natural History Museum, Department of Life Sciences, Cromwell Road, London SW7 5BD, UK.
authors.forename: J
authors.initials: J
authors.lastname: Brodie
authors.affiliation: Université de Nantes, Labotoire de Mer Molécules Santé EA 2160, Faculté des Sciences et des Techniques, B.P. 92208, 44322 Nantes cedex 3, France.
authors.forename: L
authors.initials: L
authors.lastname: Barillé
authors.affiliation: LUNAM Université, Université de Nantes, Laboratoire de Planétologie et Géodynamique UMR 6112, Faculté des Sciences et des Techniques, B.P. 92208, 44322 Nantes cedex 3, France.
authors.forename: P
authors.initials: P
authors.lastname: Launeau
authors.affiliation: UMR7266 LIENSs 'Littoral, Environnement et Sociétés', CNRS/Université de La Rochelle, Institut du Littoral et de l'Environnement, La Rochelle, France.
authors.forename: J
authors.initials: J
authors.lastname: Lavaud
authors.affiliation: School of Biological Sciences, Life Sciences Building, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK.
authors.forename: M L
authors.initials: ML
authors.lastname: Yallop
authors.affiliation: Université de Nantes, Labotoire de Mer Molécules Santé EA 2160, Faculté des Sciences et des Techniques, B.P. 92208, 44322 Nantes cedex 3, France.|University of Lisboa, Faculty of Sciences, BioISI - Biosystems &Integrative Sciences Institute, Campo Grande, 1749-016 Lisboa, Portugal.
authors.forename: B
authors.initials: B
authors.lastname: Jesus
mesh_terms: D018533:Biomass; D002113:Calcification, Physiologic; D005453:Fluorescence; D064307:Microbiota; D061848:Optical Imaging; D012624:Seaweed / Q000648:ultrastructure