title: PHYSIOLOGICAL PERFORMANCE OF FLOATING GIANT KELP MACROCYSTIS PYRIFERA (PHAEOPHYCEAE): LATITUDINAL VARIABILITY IN THE EFFECTS OF TEMPERATURE AND GRAZING(1).
abstract: Rafts of Macrocystis pyrifera (L.) C. Agardh can act as an important dispersal vehicle for a multitude of organisms, but this mechanism requires prolonged persistence of floating kelps at the sea surface. When detached, kelps become transferred into higher temperature and irradiance regimes at the sea surface, which may negatively affect kelp physiology and thus their ability to persist for long periods after detachment. To examine the effect of water temperature and herbivory on the photosynthetic performance, pigment composition, carbonic anhydrase (CA) activity, and the nitrogen (N) and carbon (C) content of floating M. pyrifera, experiments were conducted at three sites (20° S, 30° S, 40° S) along the Chilean Pacific coast. Sporophytes of M. pyrifera were maintained at three different temperatures (ambient, ambient - 4°C, ambient + 4°C) and in presence or absence of the amphipod Peramphithoe femorata for 14 d. CA activity decreased at 20° S and 30° S, where water temperatures and irradiances were highest. At both sites, pigment contents were substantially lower in the experimental algae than in the initial algae, an effect that was enhanced by grazers. Floating kelps at 20° S could not withstand water temperatures >24°C and sank at day 5 of experimentation. Maximal quantum yield decreased at 20° S and 30° S but remained high at 40° S. It is concluded that environmental stress is low for kelps floating under moderate temperature and irradiance conditions (i.e., at 40° S), ensuring their physiological integrity at the sea surface and, consequently, a high dispersal potential for associated biota.
authors.affiliation: Facultad de Ciencias del Mar, Universidad Católica del Norte, Larrondo 1281, Coquimbo, Chile Institute of Biological Sciences, Applied Ecology, University of Rostock, Albert-Einstein-Strasse 3, D-18051 Rostock, GermanyInstituto de Biología Marina, Universidad Austral de Chile, Casilla 567, Valdivia, ChileFacultad de Ciencias del Mar, Universidad Católica del Norte, Larrondo 1281, Coquimbo, ChileInstitute of Biological Sciences, Applied Ecology, University of Rostock, Albert-Einstein-Strasse 3, D-18051 Rostock, GermanyFacultad de Ciencias del Mar, Universidad Católica del Norte, Larrondo 1281, Coquimbo, Chile Centre of Research and Technological Development in Applied Phycology (CIDTA), Coquimbo, ChileFacultad de Ciencias del Mar, Universidad Católica del Norte, Larrondo 1281, Coquimbo, Chile Centro de Estudios Avanzados en Zonas Áridas, Coquimbo, Chile.
authors.forename: Eva
authors.initials: E
authors.lastname: Rothäusler
authors.affiliation: Facultad de Ciencias del Mar, Universidad Católica del Norte, Larrondo 1281, Coquimbo, Chile Institute of Biological Sciences, Applied Ecology, University of Rostock, Albert-Einstein-Strasse 3, D-18051 Rostock, GermanyInstituto de Biología Marina, Universidad Austral de Chile, Casilla 567, Valdivia, ChileFacultad de Ciencias del Mar, Universidad Católica del Norte, Larrondo 1281, Coquimbo, ChileInstitute of Biological Sciences, Applied Ecology, University of Rostock, Albert-Einstein-Strasse 3, D-18051 Rostock, GermanyFacultad de Ciencias del Mar, Universidad Católica del Norte, Larrondo 1281, Coquimbo, Chile Centre of Research and Technological Development in Applied Phycology (CIDTA), Coquimbo, ChileFacultad de Ciencias del Mar, Universidad Católica del Norte, Larrondo 1281, Coquimbo, Chile Centro de Estudios Avanzados en Zonas Áridas, Coquimbo, Chile.
authors.forename: Iván
authors.initials: I
authors.lastname: Gómez
authors.affiliation: Facultad de Ciencias del Mar, Universidad Católica del Norte, Larrondo 1281, Coquimbo, Chile Institute of Biological Sciences, Applied Ecology, University of Rostock, Albert-Einstein-Strasse 3, D-18051 Rostock, GermanyInstituto de Biología Marina, Universidad Austral de Chile, Casilla 567, Valdivia, ChileFacultad de Ciencias del Mar, Universidad Católica del Norte, Larrondo 1281, Coquimbo, ChileInstitute of Biological Sciences, Applied Ecology, University of Rostock, Albert-Einstein-Strasse 3, D-18051 Rostock, GermanyFacultad de Ciencias del Mar, Universidad Católica del Norte, Larrondo 1281, Coquimbo, Chile Centre of Research and Technological Development in Applied Phycology (CIDTA), Coquimbo, ChileFacultad de Ciencias del Mar, Universidad Católica del Norte, Larrondo 1281, Coquimbo, Chile Centro de Estudios Avanzados en Zonas Áridas, Coquimbo, Chile.
authors.forename: Iván A
authors.initials: IA
authors.lastname: Hinojosa
authors.affiliation: Facultad de Ciencias del Mar, Universidad Católica del Norte, Larrondo 1281, Coquimbo, Chile Institute of Biological Sciences, Applied Ecology, University of Rostock, Albert-Einstein-Strasse 3, D-18051 Rostock, GermanyInstituto de Biología Marina, Universidad Austral de Chile, Casilla 567, Valdivia, ChileFacultad de Ciencias del Mar, Universidad Católica del Norte, Larrondo 1281, Coquimbo, ChileInstitute of Biological Sciences, Applied Ecology, University of Rostock, Albert-Einstein-Strasse 3, D-18051 Rostock, GermanyFacultad de Ciencias del Mar, Universidad Católica del Norte, Larrondo 1281, Coquimbo, Chile Centre of Research and Technological Development in Applied Phycology (CIDTA), Coquimbo, ChileFacultad de Ciencias del Mar, Universidad Católica del Norte, Larrondo 1281, Coquimbo, Chile Centro de Estudios Avanzados en Zonas Áridas, Coquimbo, Chile.
authors.forename: Ulf
authors.initials: U
authors.lastname: Karsten
authors.affiliation: Facultad de Ciencias del Mar, Universidad Católica del Norte, Larrondo 1281, Coquimbo, Chile Institute of Biological Sciences, Applied Ecology, University of Rostock, Albert-Einstein-Strasse 3, D-18051 Rostock, GermanyInstituto de Biología Marina, Universidad Austral de Chile, Casilla 567, Valdivia, ChileFacultad de Ciencias del Mar, Universidad Católica del Norte, Larrondo 1281, Coquimbo, ChileInstitute of Biological Sciences, Applied Ecology, University of Rostock, Albert-Einstein-Strasse 3, D-18051 Rostock, GermanyFacultad de Ciencias del Mar, Universidad Católica del Norte, Larrondo 1281, Coquimbo, Chile Centre of Research and Technological Development in Applied Phycology (CIDTA), Coquimbo, ChileFacultad de Ciencias del Mar, Universidad Católica del Norte, Larrondo 1281, Coquimbo, Chile Centro de Estudios Avanzados en Zonas Áridas, Coquimbo, Chile.
authors.forename: Fadia
authors.initials: F
authors.lastname: Tala
authors.affiliation: Facultad de Ciencias del Mar, Universidad Católica del Norte, Larrondo 1281, Coquimbo, Chile Institute of Biological Sciences, Applied Ecology, University of Rostock, Albert-Einstein-Strasse 3, D-18051 Rostock, GermanyInstituto de Biología Marina, Universidad Austral de Chile, Casilla 567, Valdivia, ChileFacultad de Ciencias del Mar, Universidad Católica del Norte, Larrondo 1281, Coquimbo, ChileInstitute of Biological Sciences, Applied Ecology, University of Rostock, Albert-Einstein-Strasse 3, D-18051 Rostock, GermanyFacultad de Ciencias del Mar, Universidad Católica del Norte, Larrondo 1281, Coquimbo, Chile Centre of Research and Technological Development in Applied Phycology (CIDTA), Coquimbo, ChileFacultad de Ciencias del Mar, Universidad Católica del Norte, Larrondo 1281, Coquimbo, Chile Centro de Estudios Avanzados en Zonas Áridas, Coquimbo, Chile.
authors.forename: Martin
authors.initials: M
authors.lastname: Thiel
keywords: Chile; Macrocystis; floating; grazing; macroalgae; photosynthesis; physiology; pigments; rafting; temperature