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

1)我们制作了一条高真空管道，从海水中高效地提取CO2气体。我们采用100%磷酸加入海水后的超声波浴高效提取方法。该方法只需6分钟即可快速提取海水中的CO2气体。各萃取CO2气体的同位素组成值相同。2)参加了11次科考巡航，在世界范围内（日本周边、印度洋、西太平洋和东太平洋等）收集海水、浮游和底栖有孔虫试验、沉积物。对这些样品组进行了仔细检查，以便可能用于重建过去海水和有孔虫测试之间的同位素平衡。3)采用质谱法测定了浮游有孔虫3种优势香精（G.ruber、g.s acullifer、n.d utrei）的海水及其栖息深度。试验结果表明，橡胶、糖和水的氧同位素比相同深度海水的氧同位素分别轻0.45‰、0.37‰和0.12‰。此外，生活在同一深度的橡胶树和水蛭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，我们将在地面和底部环境中测量海水和有孔虫之间的同位素比率。实验中碳同位素不平衡（∂^<13>C_<有孔虫>-∂^<13>C_<DIC>）和氧同位素（∂^<18>C_<有孔虫>-∂^<18>C_<DIC>）分别与海水中溶解无机碳（DIC）的d18O和d13C之间的经验关系。

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.