Japan Geoscience Union Meeting 2014

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Symbol B (Biogeosciences) » B-BG Biogeosciences & Geosphere-Biosphere Interactions

[B-BG21_1AM1] Material cycles in tropical- subtropical coastal ecosystems

Thu. May 1, 2014 9:00 AM - 10:30 AM 213 (2F)

Convener:*Atsushi Watanabe(Department of Mechanical and Environmental Informatics Graduate School of Information Science and Engineering Tokyo Institute of Technology), Kazuhiko Fujita(Department of Physics and Earth Sciences, University of the Ryukyus), Chuki Hongo(Department of Physics and Earth Sciences, Faculty of Science, University of the Ryukyus), Chair:Atsushi Watanabe(Department of Mechanical and Environmental Informatics Graduate School of Information Science and Engineering Tokyo Institute of Technology), Kazuhiko Fujita(Department of Physics and Earth Sciences, University of the Ryukyus), Chuki Hongo(Department of Physics and Earth Sciences, Faculty of Science, University of the Ryukyus)

9:30 AM - 9:45 AM

[BBG21-03] Projecting impacts of rising water temperature on the distribution of seaweeds around Japan

Shintaro TAKAO1, *Masahiko FUJII1, Naoki KUMAGAI2, Hiroya YAMANO2, Yasuhiro YAMANAKA1 (1.Faculty of Environmental Earth Science, Hokkaido University, 2.National Institute for Environmental Studies)

Keywords:seaweed bed, global warming, climate model, Ecklonia cava, Sargassum duplicatum

Using monthly mean sea surface temperature (SST) from 1950 to 2035 obtained by a high-resolution climate projection model (MIROC4h) and SST-based indices of the distribution of tropical-subtropical and temperate seaweeds (Sargassum duplicatum and Ecklonia cava, respectively), we evaluated the effects of SST rises on the potential distribution of the species in seas close to Japan. Estimated distributions from the 1950s to 2000s showed that the potential southern limit of the temperate seaweed shifted to higher latitudes due to rising water temperature-induced barren ground, while there was little change in the potential northern limit of them. In contrast, the tropical-subtropical seaweed S. duplicatum expanded their distribution polewards during the same period. Under the global warming scenario (RCP4.5), the potential distribution of S. duplicatum can replace the one of E. cava in coastal area of Kochi Prefecture by the 2010s. This replacement of the temperate seaweed species with the tropical-subtropical one could consequently change coastal productivity and food web structure, and therefore may affect ecosystem services around Japan.