Climate change during the Little Ice Age from the Lake Hamana sediment record

Ara Cho, Kaoru Kashima, Koji Seto, Kazuyoshi Yamada, Takumi Sato, Kota Katsuki*

*この研究の対応する著者

研究成果: Article査読

3 被引用数 (Scopus)

抄録

Paleoenvironment and paleoclimate changes during the Little Ice Age (LIA)were investigated using sediments from Lake Hamana. This lagoon in central Japan is under a complicated climate system influenced by the East Asian summer monsoon (EASM), East Asian winter monsoon (EAWM), and strong typhoon events. Diatom assemblages and chemical components of a 1.3 m sediment core suggest historical events of rapid salination and cyclical ecosystem shifts accompanied by monsoon condition changes. Most research has indicated that Lake Hamana changed from a freshwater lake to a brackish lagoon because of the Meio earthquake in 1498 CE. However, based on results from the diatom assemblage and chemical components, this salination occurred because of changes in the Hamana paleoriver flow, and this change happened before the earthquake, around the mid-15th century. Furthermore, it is clear that Lake Hamana was an oligohaline lagoon before salination. The lithology of the lake sediments and the diatom assemblage changed during the LIA; sand, water, and total diatom contents decreased. However, the relative abundance of marine diatom taxa increased during the LIA. These changes were introduced by a weakening EASM coupled with low precipitation under low solar activity during the LIA. Several flood events represented by freshwater diatom taxa and magnetic susceptibility peaks co-occurred with strong El Niño events during the LIA. It is inferred that this strong El Niño during the LIA induced frequent typhoons causing floods in central Japan.

本文言語English
ページ(範囲)39-49
ページ数11
ジャーナルEstuarine, Coastal and Shelf Science
223
DOI
出版ステータスPublished - 2019 7 31
外部発表はい

ASJC Scopus subject areas

  • 海洋学
  • 水圏科学

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