Paleoecologic evolution of oysters since Cretaceous time investigated through formative processes of fossil and recent oyster reefs

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K03732
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 17050:Biogeosciences-related
• Research Institution: Ibaraki University
• Principal Investigator: Ando Hisao 茨城大学, 理工学研究科(理学野), 特命研究員 (50176020)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: カキ類 / カキ礁 / カキ化石 / 古生態 / 進化 / 白亜紀 / 現生 / タフォノミー

Outline of Final Research Achievements

Through field and specimen surveys on well-preserved fossil oyster beds and living oyster reefs from the Lower Cretaceous to the Recent in intertidal zones throughout Japan, the formation process of each oyster bed and reef was clarified. Taxonomic attribution and individual ecology of newly and previously collected specimens, and specimens in the collections of research institutions (universities, museums, etc.) were examined. The ecological strategies and phylogenetic evolution of oysters since the Cretaceous, and the formation and depositional processes of oyster reefs are examined and discussed, taking into account sea-level changes, comparing the results with those of Recent oyster reefs in Japan and fossil oyster beds outside Japan.

Free Research Field

層序古生物学

Academic Significance and Societal Importance of the Research Achievements

現生カキ礁は沿岸環境の保全やカキ礁自体の有機物濾過能力などで注目され，研究例は多いが，カキ礁全体の発達史に関する研究は少ない．厚岸湖の死滅カキ礁，松川浦や東京湾三番瀬の現生カキ礁でも同様である．地質時代のカキ類の生態戦略やカキ礁の進化に関する研究が幾つかあるが，そこで示されたモデルを実証する個々のカキ化石層の詳細な研究例は国内外ともに少ない．中国渤海湾の現生・完新世のカキ礁の研究が多数公表され，東京湾岸平野地下の化石カキ礁の層序的位置から縄文海進期の海水準変動曲線が復元されており，潮間帯に生息するマガキ類は海水準の示標になっており重要である．