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

自末次盛世以来深海珊瑚的放射性碳和温度的中间水记录

• 批准号: 1503129
• 负责人: Jess Adkins
• 金额: $ 25万
• 依托单位: California Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2018-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1503129&HistoricalAwards=false
• 关键词: Intermediate; Water; Records; Radiocarbon; Temperature

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.

现代海洋中的中间水域在全球热量、盐和营养物输送中发挥着重要作用，并且一直是末次盛冰期（LGM）和冰川消退的许多解释的核心。南极底水 (AABW) 对于设定过去的 pCO2 至关重要，但由于它在几乎相同的温度下上升和下沉，因此无法驱动显着的向极地热传输。另一方面，中层水域含有大量亚热带水域，在沉入亚温跃层深度之前必须先冷却。这里，源水和下沉水之间的温度差异可能很大，从而导致全球范围内重要的热传输。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，监测末次盛冰期到北大西洋冰消期中间水域的放射性碳含量和温度。研究小组将测量珊瑚化石的U系列年龄、放射性碳含量和聚集同位素组成，以限制过去约25,000年中间水域的特征。该时间序列将有助于限制中间水域在冰期和冰消期气候变化中的作用。模型已经预测，并且一些研究已经发现，Heinrich Stadial 1 (HS1)期间的中间深度变暖，并且由此产生的数据将特别适合研究自末次冰期以来中间环流的速率和热含量。资金用于支持博士生的培训，以及通过公开讲座和短片宣传海洋与气候之间的联系。