Development and application of geochemical tracers for paleo and modern oceanography

人为二氧化碳的增加可能会改变未来的气候，我们必须提高我们的预测能力，以决定最佳的社会反应。海洋通过控制大气中的二氧化碳和重新分配入射的太阳热量，在调节地球气候方面发挥着关键作用。海水中两种天然放射性同位素（230 Th和231 Pa）的分布提供了关于现代海洋中粒子动力学、碳通量和深水环流的重要信息，可用于更好地量化对气候变化至关重要的海洋过程。此外，本发明还提供了一种方法，在沉积记录中加入这些同位素，提供了一种评估这些海洋过程与过去气候变化的时间演变的方法，并提供了区分人为活动引起的气候趋势和反复出现的自然循环所需的时间背景。我将测量溶解在海水中并与海洋颗粒有关的230 Th和231 Pa的详细水柱剖面这将补充正在西北大西洋进行的工作。这些配置文件将带来通风的定量信息（大西洋）和（太平洋）的上升流率，以及控制海洋颗粒下沉速率和碳固存到深海的因素。这些信息将被放置在更大的时间背景下，使用230 Th和231 Pa的沉积记录，以进一步记录碳通量和深海的变化。水循环与晚第四纪和全新世的气候变化有关。大西洋沉积物提供了对深水形成的过去变化及其在触发气候突变中的作用的见解（由CFCAS资助的工作）。我将通过整合230 Th，231 Pa和有孔虫Mg/Ca在多PI，多代理研究太平洋的环流和生产力的过去的变化来补充这项研究。

The rise in anthropogenic CO2 may alter future climate and we must improve our predictive capabilities to decide on optimal societal responses. The ocean plays a critical role in regulating Earth's climate by controlling atmospheric CO2 and by redistributing incoming solar heat. The distribution of two natural radioisotopes (230Th and 231Pa) in seawater provides important information on particle dynamics, carbon fluxes and deep-water circulation in the modern ocean, which can be used to better quantify oceanic processes important for climate change. In addition, the incorporation of these isotopes in the sedimentary record provides a means of assessing the temporal evolution of these oceanic processes in relation to past climate changes and provides the needed temporal context to distinguish between climatic trends induced by anthropogenic activities and recurring natural cycles.I will measure detailed water column profiles of 230Th and 231Pa dissolved in seawater and associated with marine particles in the northeastern and equatorial Pacific which will complement on-going work in the northwestern Atlantic. These profiles will bring quantitative information on ventilation (Atlantic) and upwelling (Pacific) rates of deep water, and on the factors controlling the sinking rates of marine particles and the sequestration of carbon into the deep sea.This information will be placed in a larger temporal context using the sedimentary record of 230Th and 231Pa to further document changes in carbon flux and deep-water circulation associated with climatic shifts during the late Quaternary and the Holocene. Atlantic sediments provide insights into past changes in deep water formation and their role in triggering abrupt climate changes (work funded by CFCAS). I will complement this study by integrating the 230Th, 231Pa, and foraminifera Mg/Ca in a multi-PIs, multiproxy study of past changes in the circulation and productivity of the Pacific Ocean.