Japan Geoscience Union Meeting 2015

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Symbol M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

[M-IS30] Evolution of the Pelagic Realm

Tue. May 26, 2015 11:00 AM - 12:45 PM 304 (3F)

Convener:*Atsushi Matsuoka(Department of Geology, Faculty of Science, Niigata University), Toshiyuki Kurihara(Graduate School of Science and Technology, Niigata University), Yasuhiro Kato(Department of Systems Innovation, Graduate School of Engineering, University of Tokyo), Tetsuji Onoue(Earth and Environmental Sciences, Graduate School of Science and Technology, Kumamoto University), Katsunori Kimoto(Japan Agency for Marine-Earth Science and Technology), Tatsuo Nozaki(Institute for Research on Earth Evolution, Japan Agency for Marine-Earth Science and Technology), Hayato Ueda(Department of Geology, Niigata University), Kenta Kobayashi(Department of Geology, Faculty of Science, Niigata University), Takashi Hasegawa(Division of Global Environmental Science and Engineering, Graduate School of Natural Science and Technology, Kanazawa University), Chair:Tetsuji Onoue(Earth and Environmental Sciences, Graduate School of Science and Technology, Kumamoto University), Atsushi Matsuoka(Department of Geology, Faculty of Science, Niigata University)

11:30 AM - 11:45 AM

[MIS30-10] What does the radiolarian Spumellaria/Nassellaria ratio indicate?

*Atsushi MATSUOKA1 (1.Niigata University)

Keywords:radiolaria, Nassellaria, Spumellaria, paleoenvironment, proxy, pelagic realm

Spumellaria and Nassellaria are major orders in radiolarians. The Spumellaria/Nassellaria ratio has been used in monitoring environmental changes in the past oceans. However, what the ratio indicates is not well understood. It is noteworthy to point out that the ratio is strongly affected by taphonomic processes and careful application is needed. Detailed observations of a variety in feeding behavior of cultured radiolarian specimens make it possible to understand the relationship between skeletal morphology and feeding behavior. Multi-segmented nassellarians require much larger prey than any other radiolarians. The ratio of multi-segmented nassellarians to total radiolarians is regarded as another proxy in monitoring ecosystem in the pelagic realm.