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Carbon and Oxygen isotope equilibrium between foraminifera test and sea water, its implications for paleoceanography

有孔虫测试和海水之间的碳和氧同位素平衡及其对古海洋学的影响

基本信息

批准号：
13440155
负责人：
MURAYAMA Masafumi
金额：
$ 9.54万
依托单位：
Kochi University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-13440155/
关键词：
Foraminifera Seawater Sediment Core Isotope equilibrium fractionation Paleoceanography 有孔中

项目摘要

1)We made a high vacuum line to extract the CO2 gas efficiently from seawater. We adopt an efficient extraction method using an ultrasonic bath after 100% phosphoric acid added to seawater. This method can extract rapidly the CO2 gas from seawater only for 6 minutes. The isotope composition of the extraction CO2 gas in each shows same value respectively.2)We participated the 11 research cruises to collect the seawater, planktonic and benthic foraminifera tests, sediments in the world wide area(around Japan, Indian Ocean, western and eastern Pacific Ocean and so on). These sample sets are closely examined for possible use as a reconstruction of isotope equilibrium between the seawater and foraminifera tests in the past.3)The seawater and its dwelling depths of three dominant spices of planktonic foraminifera(G.ruber, G.sacculifer, N.dutertrei) were measured carbon and oxygen isotope ratios using a mass spectrometry. As tentative results, the oxygen isotope ratios of the G.ruber, G.sacculifer, N.dutertrei tests are 0.45‰、0.37‰、0.12‰ lighter than that of seawater at the same depths, respectively. Furthermore, oxygen isotope ratios of the G.ruber and G.sacculifer which dwell at the same depth have same difference from that of seawater. Thus, we will be going to measure the isotope ratio between seawater and foraminifera tests at surface and bottom environments. The empirical relations between isotopic disequilibria in carbon(∂^<13>C_<foraminifera>-∂^<13>C_<DIC>) and oxygen isotopes (∂^<18>C_<foraminifera>-∂^<18>C_<DIC>) in the tests and the seawater d18O and d13C of dissolved inorganic carbon(DIC), respectively, will be induced.

1)研制了一条从海水中高效提取二氧化碳气体的高真空线。在海水中加入100%磷酸后，采用超声波法提取。该方法只需6分钟即可从海水中快速提取二氧化碳气体。2)参加了11个考察航次，采集了全球范围内(日本周边、印度洋、西太平洋和东太平洋等)的海水、浮游和底栖有孔虫测试、沉积物等。这些样本组被仔细检查，以用于重建海水和有孔虫之间的同位素平衡。3)利用质谱仪测量了三种浮游有孔虫(G.ruber、G.sacculifer、N.dutertrei)的海水及其栖息深度。作为初步结果，橡胶棉、球囊棉、杜特特里藻的氧同位素比值分别比相同深度的海水轻0.45‰、、0.37‰、、0.12‰。此外，在相同深度栖息的红藻和球藻的氧同位素比值与海水的氧同位素比值也有相同的差异。因此，我们将测量海水和有孔虫在表层和海底环境中的同位素比率。建立了carbon(∂^&lt；13&gt；C_&lt；foraminifera&gt；-∂^&lt；13&gt；C_&lt；DIC&gt；)和氧同位素(∂^&lt；18&gt；C_&lt；foraminifera&gt；-∂^&lt；18&gt；C_&lt；DIC&gt；)与海水中溶解无机碳的d18O和d13C的经验关系。