Collaborative Research: Radiocarbon content of the Southwest Pacific and Southern Ocean waters in the Holocene and late Quaternary

学术价值：由于海洋环流的变化在过去对气候产生了深远的影响，因此该项目解决了海洋环流在二氧化碳调节中所起的基本作用。这项工作使用了在新西兰附近沉积物中沉积的有孔虫测试中的放射性碳来研究全球海洋环流如何影响海洋和大气之间温室气体二氧化碳的分配。这项工作有两个主要目标：(1)重建南太平洋冰川的放射性碳特征，以证实或反驳一个足够古老的深水块的存在，以解释大气二氧化碳在冰期-间冰期的变化；(2)在冰川消退的不同时间间隔产生高分辨率的放射性碳记录，以提供南半球的视角，这是全球二氧化碳和放射性碳预算中缺失的。海洋环流可以用放射性碳（14C）来追踪，因为大气中二氧化碳的14C含量与海洋中以溶解的碳酸盐和碳酸氢盐的形式存在的14C含量之间存在可量化的差异。此外，该项目还利用了火山灰层在不同水深的海底沉积物中提供的精确地层控制。浮游生物和底栖有孔虫对将用于构建海洋不同深度的放射性碳垂直剖面，并将收集时间序列的氧同位素数据，以跟踪浅水区（600-2500米）和深水区（600-4300m）在最后一次消冰期（17,500至9,500年前）的变化演变。更广泛的影响：该项目包括美国和新西兰科学家之间的合作、学生培训，以及对一名在科学领域性别代表性不足的早期职业研究者的支持。

Intellectual merit: Because changes in ocean circulation have profoundly influenced climate in the past, this project addresses the fundamental role that ocean circulation plays in the regulation of CO2. The work uses radiocarbon in foraminifera tests deposited in sediments off New Zealand to examine how global ocean circulation affects the partitioning of the greenhouse gas CO2 between the ocean and atmosphere. The work has two primary goals: (1) to reconstruct the radiocarbon signature of the glacial Southern Pacific to confirm or refute the presence of a deep water mass old enough to account for the glacial-interglacial changes in atmospheric CO2 and (2) to produce a high resolution record of radiocarbon at various intervals the time of deglaciation to provide a Southern Hemisphere perspective, which is missing from global CO2 and radiocarbon budgets. Ocean circulation can be traced with radiocarbon (14C) because there is a quantifiable difference between the 14C content of atmospheric CO2 gas and that in the ocean where it exists in the form of dissolved carbonate and bicarbonate. In addition, this project takes advantage of the precise stratigraphic control afforded by volcanic ash layers in cored, off-shore sediments from different water depths. Planktonic and benthic foraminiferal pairs will be used to construct vertical profiles of radiocarbon at different depths in the ocean and a time series of oxygen isotope data will be collected to track the evolution of changes in shallow waters (600-2500 m) and deep waters (600-4300m) through the time of the last period of deglaciation (17,500 to 9,500 years ago). Broader impacts: The project includes collaboration between US and New Zealand scientists, student training, and the support of an early career investigator whose gender is under-represented in the sciences.