Evolution of life-history strategy and paleoclimate changes from an geochemical record of a cave-dwelling marine micro-bivalve.

2012 Fiscal Year Final Research Report

• Project/Area Number: 22540475
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Stratigraphy/Paleontology
• Research Institution: Shizuoka University
• Principal Investigator: KITAMURA Akihisa 静岡大学, 理学部, 教授 (20260581)
• Co-Investigator(Kenkyū-buntansha): UBUKATA Takao 静岡大学, 理学部, 准教授 (00293598)
• Co-Investigator(Renkei-kenkyūsha): TOYOFUKU Takashi 独立行政法人海洋研究開発機構, 研究員 (30371719) ; ISHIMURA Toyoho 独立行政法人産業技術総合研究所, 派遣職員(研究員) (80422012)
• Project Period (FY): 2010 – 2012
• Keywords: 海底洞窟 / 微小二枚貝 / 酸素同位体 / 沖縄 / 生活史 / 気候変動 / 完新世

Research Abstract

Cave-dwelling micro-bivalve Carditella iejimensis,which is less than 3.5 mm in height and length, inhabits the sediment surfacein a submarine cave off the Okinawa Islands, Japan. The result of mark-release and recapture surveys indicates that the species is potentially able to undergo year-round continuous growth. If this interpretation is correct, the shell probably requires more than 1 year to reach 1 mm in height, and 4 years to reach 3 mm; consequently, the lifespan for C. iejimensis is estimated to be at least 4 years. To evaluate the use of this species as a quantitative paleoceanographic proxy, we analyzed the δ18O values of 60 living C. iejimensisspecimens collected from the submarine cave. Results show that most individuals preserve δ18O values corresponding to the mean annual temperature and δ18O of seawater. These results, when applied to fossil shell δ18O records from the cave, indicate that the recent warming is likely exceptional, when viewed in the context of the past 7000 years paleotemperature record, which includes the Medieval Warm Period and the Middle Holocene Climatic Optimum.

Research Products

• [Journal Article] Evidence of recent warming in the Okinawa region, subtropical northwestern Pacific (2013)
  • Author(s): Kitamura, A., Kobayashi, K., Tamaki, C., Yamamoto, N., Irino, T., Miyairi, Y. and Yokoyama, Y
  • Journal Title: from an oxygen isotope record of a cave-dwelling marine micro-bivalve. Paleontological Research Volume: 17 Pages: 58-68
  • DOI: DOI:10.2517/1342-8144-17.1.58
  • Peer Reviewed
• [Journal Article] Growth of a submarine cave-dwelling micro-bivalve (2012)
  • Author(s): Kitamura, A., Yamamoto, N. and Kobayashi K
  • Journal Title: Carditella iejimensis Volume: 70 Pages: 41-45
  • Peer Reviewed
• [Presentation] 7 千年間の海底洞窟性微小二枚貝の酸素同位 体比変動から見た沖縄海域の現在の温暖化 (2012)
  • Author(s): 北村晃寿・小林小夏・玉置周子・山本なぎさ・入野智久・宮入陽介・横山祐典
  • Organizer: 日本古生物学会
  • Place of Presentation: 名古屋大学,愛知県
  • Year and Date: 2012-06-30
• [Presentation] 海底洞窟性微小二枚貝Carditella iejimensisの酸素同位体比について (2011)
  • Author(s): 北村晃寿・小林小夏・玉置周子・山本なぎさ・入野智久・宮入陽介・横山祐典
  • Organizer: 日本古生物学会
  • Place of Presentation: 金沢大学,石川県.
  • Year and Date: 2011-07-03
• [Remarks]
  • URL: http://homepage3.nifty.com/a-kitamura/index.html