title: EFFECT OF TEMPERATURE AND GRAZING ON GROWTH AND REPRODUCTION OF FLOATING MACROCYSTIS SPP. (PHAEOPHYCEAE) ALONG A LATITUDINAL GRADIENT(1).
abstract: Macroalgal rafts frequently occur floating in coastal waters of temperate regions of the world's oceans. These rafts are considered important dispersal vehicles for associated organisms with direct development. However, environmental factors may limit the floating potential of kelp and thereby the dispersal of associated organisms. To examine the effect of water temperature and grazing on growth, reproductive output, and survival of floating Macrocystis spp., experiments were conducted in outdoor tanks during austral summer 2006/2007 at three sites along the Chilean Pacific coast (20° S, 30° S, 40° S). At each site, Macrocystis spp. was maintained individually at three different water temperatures (ambient, ambient - 4°C, ambient + 4°C) and in the presence or absence of the amphipod grazer Peramphithoe femorata for 14 d. High water temperatures (>20°C) provoked rapid degradation of Macrocystis spp. rafts. At moderate temperatures (15°C-20°C), algal survival depended on the presence of associated grazers. In the absence of grazers, algal rafts gained in biomass while grazing caused considerable losses of algal biomass. Algal survival was the highest under cooler conditions (<15°C), where raft degradation was slow and grazer-induced biomass losses were compensated by continuing algal growth. Our results indicate that floating kelp rafts can survive for long time periods at the sea surface, but survival depends on the interaction between temperature and grazing. We suggest that these processes limiting the survival of kelp rafts in warmer temperatures may act as a dispersal barrier for kelp and its associated passengers.
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 Facultad 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 Facultad 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 Facultad 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 Facultad 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 Facultad 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 Facultad 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; detachment; floating; grazing; growth; macroalgae; rafting; reproduction; temperature