Development of new carbonate dissolution index by X-ray Tomography and geochemical proxies

2014 Fiscal Year Final Research Report

• Project/Area Number: 24540505
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Stratigraphy/Paleontology
• Research Institution: Japan Agency for Marine-Earth Science and Technology
• Principal Investigator: KIMOTO Katsunori 独立行政法人海洋研究開発機構, 地球環境観測研究開発センター, 主任技術研究員 (40359162)
• Co-Investigator(Kenkyū-buntansha): SASAKI Osamu 東北大学, 総合学術博物館, 准教授 (60222006) ; IRINO Tomohisa 北海道大学, 地球環境科学研究院, 助教 (70332476)
• Co-Investigator(Renkei-kenkyūsha): WAKITA Masahide 独立行政法人海洋研究開発機構, むつ研究所, 技術研究員 (30415989)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: マイクロフォーカスX線CT / 浮遊性有孔虫 / 微量元素比 / 海洋酸性化 / 炭酸塩溶解

Outline of Final Research Achievements

We developed a novel method to know the shell density of calcareous zooplankton (foraminiera) by using Micro X-ray Computing Tomography (MXCT) successfully. We found that shell density of individual planktic foraminifers which were recovered by the sediment trap deployed at Stn. K2 (47N, 160E), North Pacific had remarkably changed seasonally. In particular, shell degradation progressed in winter season from December to April. According to observations of seawater chemistry, shell density changes might be closely associated with carbonate systems and related physicochemical parameters: vertical mixing, pH, TCO2 and Omega. Geochemical proxy (strontium-calcium ratio, Sr/Ca) of individual foraminiferal shell indicated strong correlation with shell density, and it suggests that Sr/Ca of foraminiferal shells has potential to be a quantitative tracer of carbonate dissolution. These result should contribute to understand material cycles of ocean and biogeochemical cycles.

Free Research Field

微古生物学