Accurate Calibration of Multiple Paleoceanographic Proxies in Benthic Foraminifera

根据这项奖励，PIS将在几种底栖有孔虫中校准多个古海洋地球化学指标。这项工作将对底栖有孔虫地球化学指标的理解和应用作出重大贡献。由于这种测量构成了许多古气候研究的基础，改进的校准是必要的，并将得到广泛应用。代用指标包括温度和盐度(镁/钙，d18O)、营养成分(镉/钙、锌/钙、d13C)、pH(D11B)以及可能的碳酸盐离子浓度(U/Ca、Li/Ca)的估计值。2002年，从佛罗里达和古巴之间的38个地点采集了一系列多核表层和海水样本，专门为此目的。这次采集是一个独特的校准机会，原因有几个：(1)丰富的底栖有孔虫、高沉积速率和大量采集的沉积物使近现代标本能够进行多次测量；(2)采样地点涵盖了目标参数的很大范围(如15C、1.9PSU、0.24 pH)；以及(3)从安装在多岩心取样器上的Niskin瓶中收集的海水可准确确定原位水条件，即矿化度、D18O、元素浓度和碳酸盐体系参数(可从随附的CTD铸模获得准确的温度)。

Under this award the PIs will calibrate multiple paleoceanographic geochemical proxies in several species of benthic foraminifera. This work should contribute significantly to the understanding and application of benthic foraminiferal geochemical proxies. Since such measurements form the foundation of many paleoclimatic studies, improved calibrations are essential and will be widely employed. Proxies include estimators for temperature and salinity (Mg/Ca, d18O), nutrient content (Cd/Ca, Zn/Ca, d13C), pH (d11B), and possibly carbonate ion concentration (U/Ca, Li/Ca). A series of multicore tops and seawater samples were collected from 38 locations between Florida and Cuba in 2002, expressly for this purpose. This collection represents a unique calibration opportunity for several reasons: (1) abundant benthic foraminifera, high sedimentation rates, and large volumes of collected sediment allow for multiple measurements of near-modern specimens; (2) the sites span large ranges of the targeted parameters (e.g., 15 C, 1.9 psu, 0.24 pH); and (3) seawater collected from a Niskin bottle mounted on the multicorer provides accurate determinations of in-situ water conditions, namely salinity, d18O, elemental concentrations, and carbonate system parameters (accurate temperatures are available from accompanying CTD casts).