Maintenance of Preindustrial Atmospheric pCO2 Levels: Recalibration of a Carbon Isotopic Paleobarometer and PCO2 Mapping of the Late Quaternary Global Ocean

长链烯酮的碳同位素组成将与代表性海水中共存的有孔虫碳酸盐的碳同位素组成进行比较，这些海水中溶解的二氧化碳浓度也是已知的。其目的将是检验碳同位素分馏和二氧化碳水平之间的关系，从而校准“二氧化碳古气压计”。在寒冷的高纬度水域，JGOFS北大西洋水华实验期间收集的材料将检查悬浮和下沉的物质。关于该地点溶解二氧化碳的浓度和同位素组成的大量数据已经可用。也有来自南大洋样带的烯酮和碳酸盐，以及碳酸盐化学和同位素组成的数据。在地表水较暖的低纬度地区，将检查来自东赤道太平洋JGOFS站点的材料。烯烃将从悬浮颗粒有机碳中获得。溶解二氧化碳的浓度和同位素组成可从联合地球观测系统的报告中获得，有孔虫的同位素组成将在这项工作中确定。实际到达沉积物水界面的同位素信号将通过分析挪威海（高纬度、低温地点）和东赤道太平洋JGOFS地点的岩心顶部的材料来进行检查。

The carbon-isotopic compositions of long-chain alkenones will be compared to those of coexisting foraminiferal carbonates in representative in representative ocean waters for which the concentration of dissolved carbon dioxide is also known. The objective will be to examine relationships between carbon-isotopic fractionations and CO2 levels, thus calibrating a "CO2 paleobarometer." In cold, high latitude waters, both suspended and sinking materials will be examined in materials collected during the JGOFS North Atlantic Bloom Experiment. Extensive data on the concentration and isotopic composition of dissolved CO2 are already available for that site. Alkenones and carbonates from Southern Ocean transects are also available, as are data on carbonate chemistry and isotopic composition. At lower latitudes with warmer surface waters, materials from the Eastern Equatorial Pacific JGOFS site will be examined. Alkenones will be obtained from suspended particulate organic carbon. Concentrations and isotopic compositions of dissolved CO2 are available from JGOFS reports and the isotopic composition of forams will be determined in the course of this work. Isotopic signals actually reaching the sediment water interface will be examined through analyses of materials from core tops in the Norwegian Sea (high-latitude, low-temperature site) and at the Eastern Equatorial Pacific JGOFS site.