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量、盐分和营养物质的输送中扮演着重要的角色，并一直是许多关于末次冰盛期(LGM)和冰川消融的解释的核心。南极底层水(AABW)对过去二氧化碳浓度的形成至关重要，但由于它的上升和下沉温度几乎相同，它不能驱动显著的向极地的热量输送。另一方面，中层水域含有大量的亚热带水域，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，从而产生了全球显著的热传输。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，监测从北大西洋冰川消融到末次冰川的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、放射性碳含量和块状同位素组成，以限制过去约25,000年来中间水域的特征。这一时间序列将有助于限制中间水在冰川和非冰川气候变化中的作用。模型预测了海因里希阶梯1(HS1)期间的中间深度变暖，并发现了一些研究发现，由此产生的数据将唯一适合于调查自上一次冰川时期以来中间环流的速率和热含量。资金支持一名博士生的培训，以及通过关于海洋与气候之间联系的公开讲座和短片进行宣传。

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.