Direct Determination of the pH Distribution in the Glacial Oceans Based on the Boron Isotope Composition of Foraminifera

小行星9402263 为解释冰芯中记录的大气CO2含量中80 ppm的冰期与间冰期差异而设计的情景可以分为两类，一类涉及海洋的生物泵，另一类涉及海洋的CaCO 3循环。前一组受到最多的关注，但有孔虫的镉浓度和碳同位素测量似乎对他们的规则。 后一组在某种程度上已被立即拒绝，因为深海沉积物的溶解记录似乎表明，实现所观察到的大气CO2变化所需的CO 32含量变化相当大。 最近，Archer和Maier-Reimer找到了一种绕过解散记录约束的方法。 他们表明，由于呼吸的影响，二氧化碳释放到上层厘米的沉积物，它是可能有一个相当大的变化，在稳定状态溶跃层深度。 本研究将采用硼同位素方法来确定Archer和Maier-Reimer方案是否可行。 对成对的冰川和全新世有孔虫（底栖和浮游）的初步测量表明，海洋的pH值，如阿彻和迈尔-赖默情景所要求的，在冰川时期高出0.2至0.3个单位。 本研究的主旨是使更多的这样的测量具有最高的可达到的精度，并探讨硼同位素pH值方法应用于海洋碳酸钙的基础上的许多假设的有效性。

9402263 BROECKER Scenarios designed to explain the 80 ppm glacial to interglacial difference in atmospheric CO2 content recorded in ice cores can be placed into tow categories, those involving the ocean's biologic pump and those involving the ocean's CaCO3 cycle. The former group received most attention; but cadmium concentration and carbon isotope measurements on foraminifera appear to rule against them. The latter group have, to some extent, been rejected out of hand because the dissolution record for deep sea sediments appears to dictate against the rather large CO32 content changes required to accomplish the observed atmospheric CO2 change. Recently Archer and Maier-Reimer have found a way around the dissolution record constraint. They show that because of the influence of respiration CO2 released to the upper centimeter of sediment it is possible to have a rather large change in the steady state lysocline depth. This study will employ the boron isotope method to determine whether the Archer and Maier-Reimer scenario is feasible. Preliminary measurements on paired glacial and holocene foraminifera (both benthic and planktonic) suggest that the ocean's pH was, as required by the Archer and Maier-Reimer scenario, 0.2 to 0.3 units higher during glacial time. The thrust of this research is to make more such measurements with the highest attainable accuracy and also to explore the validity of the numerous assumptions on which the boron isotope pH method as applied to marine CaCO3 is based.