11:30 〜 11:45
[MIS30-10] 放散虫のSpumellaria/Nassellaria比は何を示しているのか？
キーワード：放散虫, ナッセラリア, スプメラリア, 古環境, 代替指標, 遠洋域
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.