Intermediate Water Records of Radiocarbon and Temperature from Deep-sea Corals since the LGM

现代海洋中的中间水在全球热、盐和营养物质的运输中起着重要作用，并且是末次盛冰期（LGM）和冰川消融的许多解释的核心。南极底水（AABW）对于确定过去的二氧化碳分压至关重要，但由于它在几乎相同的温度下上涌和下沉，它无法驱动显著的极地热输送。另一方面，中间水域包含亚热带水域的很大一部分，在下沉到亚温跃层深度之前必须冷却。在这里，源水和下沉水之间的温度差异可能很大，从而引起全球显著的热输送。这项研究将利用从新英格兰海山收集的现有深海珊瑚样本，监测北大西洋冰川消融期间LGM中间水域的放射性碳含量和温度。研究小组将测量化石珊瑚的u系列年龄、放射性碳含量、块状同位素组成，以限制过去~ 25000年中间水域的特征。这个时间序列将有助于限制中间水在冰期和去冰期气候变化中的作用。一些模式已经预测了海因里希历1 （HS1）期间的中深度变暖，一些研究也发现了这一点，由此得出的数据将特别适合于研究末次冰期以来中环流的速率和热含量。资金用于培养一名博士生，以及通过公开讲座和短视频宣传海洋与气候之间的联系。

Intermediate waters in the modern ocean play an important role in global heat, salt, and nutrient transports, and have been at the heart of many explanations of the Last Glacial Maximum (LGM) and the deglaciation. Antarctic Bottom Water (AABW) is crucial in setting the pCO2 of the past but because it upwells and sinks at virtually the same temperature, it is not capable of driving significant poleward heat transport. Intermediate waters, on the other hand, contain a large component of subtropical waters that must cool before sinking to sub-thermocline depths. Here temperature contrasts can be large between source waters and sinking waters giving rise to globally significant heat transports.This research will monitor the radiocarbon content and temperature of intermediate waters from the LGM through the deglaciation in the North Atlantic, using existing deep sea coral samples collected from the New England Seamounts. The research team will measure the U-series ages, radiocarbon content, and clumped isotope composition of the fossil corals to constrain the characteristics of intermediate waters over the past ~25,000 years. This time series will help constrain the role of intermediate waters in glacial and deglacial climate change. Models have predicted, and a few studies have found, intermediate depth warming during Heinrich Stadial 1 (HS1), and the resulting data will be uniquely suited to investigate the rate and heat content of the intermediate circulation since the last glacial period. Funding supports the training of a PhD student, as well as outreach via public lectures and short videos on the links between the oceans and climate.