2009 Fiscal Year Final Research Report
Global and local environmental changes and biological evolution : paleolimnological and molecular biological analyses using resting eggs of Daphnia in sediments
| Project/Area Number |
19207003
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Ecology/Environment
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| Research Institution | Tohoku University |
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Principal Investigator |
URABE Jotaro Tohoku University, 大学院・生命科学研究科, 教授 (50250163)
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| Co-Investigator(Kenkyū-buntansha) |
KAWATA Masakado 東北大学, 大学院・生命科学研究科, 教授 (90204734)
YOKOYAMA Jun 山形大学, 理学部, 教授 (80272011)
UEDA Shingo 日本大学, 生物資源科学部, 准教授 (40318390)
ODA Hirotaka 名古屋大学, 年代測定総合研究センター, 助教 (30293690)
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| Project Period (FY) |
2007 – 2009
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| Keywords | 古陸水学 / 植物プランクトン / 動物プランクトン / 湖 / 堆積物 / 休眠卵 / ミジンコ / 高山湖沼 |
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| Research Abstract |
Historical changes shown by genetic analysis using resting eggs of Daphnia in the sediments indicated that Daphnia species in Hataya-Onuma pond, Yamagata Prefecture has produced the hybrids within Daphnia galeata-dentifera species complex since the 1950s. Despite drastic environmental changes thorough the last several decades, they have kept its population. In the 1980s, other species of Daphnia pulex established its population in the pond probably due to the reduced predation pressure from planktivore fish by introduced black bass. As a result, multiple Daphnia species could have coexisted in this pond since then. Meanwhile, the analysis of plankton remains in Lake Hourai-Numa, Iwate prefecture, showed that a new species of Daphnia population increased after the 1990s when the abundance of phytoplankton drastically increased in parallel with the abrupt increase of TN and TP concentrations. The results suggest that the phyto- and zooplankton communities have been changed due to effects of nutrient loading since the 1980s. Since we did not detect direct anthropogenic effects in the watersheds, recent increase in nutrient loadings to this lake are most likely brought by air deposition.
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