Collecting Deep-sea Corals from off of Tasmania to Measure the History of Southern Ocean Radiocarbon Concentrations

在南大洋，南极中间水(AAIW)和亚南极模式水(SAMW)决定了热带温跃层底部的性质，因此在热带地区改变全球气候的能力中发挥着重要作用。南极底水(AABW)填满了全球大部分深海，因此是衡量海洋储存和释放二氧化碳能力的最重要的储水池。出于这些原因，这些水团向中层和深海通风的速度是许多冰期-间冰期气候变化和快速气候变化理论中的一个关键参数。这项提议将通过收集塔斯马尼亚南部的深海珊瑚化石来限制南大洋的历史，然后以冰芯分辨率测量Delta14C的过去剖面。放射性碳是关键的示踪剂，因为它固有的时间信息可以让我们限制深循环的速度。众所周知，塔斯马尼亚以南的水域含有丰富的现代珊瑚和化石珊瑚，该地区的水深测量非常适合在500至3000米深的地方找到样本。在这个项目中，我计划进行一个双邮轮采样计划；邮轮1号将与CSIRO船只Southern Surveyor和来自世界卫生组织的自主海底探险者号(ABE)一起绘制该地区的地图并进行调查；邮轮2将与联合国海事组织的一艘船和ROV Jason号从邮轮1中确定的关键地点收集珊瑚并描述其特征。PI将存档所有样本，并将其提供给所有希望研究这些样本的研究人员。针对中学理科学生的在线更新和背景信息计划在邮轮上进行。

In the Southern Ocean, Antarctic Intermediate Water (AAIW) and sub-Antarctic Mode Water (SAMW) set the properties of the base of the tropical thermocline, and therefore play an important role in the tropics' ability to alter global climate. Antarctic Bottom Water (AABW) fills much of the global abyssal depths, and is therefore the most important reservoir in measuring the ocean's ability to store and release CO2. For these reasons, the rate at which these water masses ventilate the intermediate and deep ocean is a key parameter in many theories of glacial-interglacial climate change, and rapid climate shifts. This proposal will constrain the Southern Ocean's history by collecting fossil deep-sea corals from south of Tasmania to then measure the past profiles of Delta14C, at ice core resolution. Radiocarbon is the crucial tracer because its inherent time information lets us constrain deep circulation rates. The waters south of Tasmania are known to contain abundant modern and fossil corals and the bathymetry of the region is well suited to find samples between 500 and 3,000 meters deep. In this project, I plan to conduct a a two-cruise sampling program; cruise 1 will map and survey the area with the CSIRO vessel Southern Surveyor and the Autonomous Benthic Explorer (ABE) from WHOI, cruise 2 will collect and characterize corals from the key locations identified in cruise 1 with a UNOLS vessel and the ROV Jason. The PI will archive all samples and make them available to all researchers who wish to work on them. A web-basedprogram of daily updates and background information geared towards middle school science students is planned for the cruises.