History of ecosystem disturbances associated with mega-tsunamis in the Sanriku Coast reveled by genetic population structure of direct-developing species

2014 Fiscal Year Final Research Report

• Project/Area Number: 24651004
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Environmental dynamic analysis
• Research Institution: The University of Tokyo
• Principal Investigator: KOJIMA Shigeaki 東京大学, 新領域創成科学研究科, 教授 (20242175)
• Co-Investigator(Kenkyū-buntansha): MATSUMASA Masatoshi 岩手医科大学, 共通教育センター, 教授 (50219474)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 三陸海岸 / 巨大津波 / ホソウミニナ / コアレセント理論 / ベイス法 / 集団サイズ変動

Outline of Final Research Achievements

Distribution of tideland snails on the Sanriku Coast was surveyed in May 2012. In some areas, their main habitats have been lost but a few individuals survived in the neighboring habitats. Peaks of recruitment of the Asian horn snail Batillaria attramentaria, which is a direct-developing species, were recognized each once in spring and summer in the northern part of the Sanriku region. Phylogeographic analyses based on the coalescence theory were conducted to reveal historical changes of population size of this species. By analyses using nucleotide sequences of a mitochondrial COI gene and a nuclear ITS1 region, a rapid decrease of the population size during the last glacial period and a subsequent recovery were shown. Analyses using 28 kinds of microsatellites showed rapid decreases of the population size corresponding to the 2011 Tohoku Earthquake and the Chile Tsunami in 1960.

Free Research Field

分子生態学