Sub-annual climate variability during the last deglaciation: New views from coralline biogeochemistry

如果我们回到18000年前，我们几乎认不出我们的星球。如今人口密集的北半球许多地方都是冰冻的荒地：冰川覆盖了纽约和柏林的城市，伦敦和巴黎后来建立的地方是永久冻结的。然而不久之后，这些冰开始融化。海洋被淡水淹没，导致海平面上升，改变了海洋环流的模式。我们在这个提案中想要回答的问题是，这种环流模式的变化对地球气候有什么影响？问题在于，对气候（例如温度）的直接测量只能追溯到过去几百年，因此这些信息必须通过所谓的代用物或“替代品”来重建。珊瑚是特别有用的代用品，因为它们可以准确地确定年代，它们的化学成分反映了许多重要的环境参数，比如它们生长的水域的温度。在这里，我们建议获得塔希提岛2万至1万年前珊瑚骨骼化学成分变化的记录。独特的是，我们将使用新的激光技术，使我们能够获得极高分辨率的记录（几天到几个月）。这意味着我们将能够捕捉到能够影响地球上从冰川到更温暖环境转变的短期事件。

If we travelled back in time some 18 000 years, we would hardly recognise our planet. Many parts of the Northern Hemisphere that are densely populated today were frozen wastes: glaciers covered the cities of New York and Berlin, and the ground where London and Paris would become established was permanently frozen. Not long after however, this ice began to melt. The oceans were flooded with fresh water, causing sea level to rise and changing the pattern of ocean circulation. The question that we want to answer in this proposal, is what effect did this change in the pattern of circulation have on Earth's climate? The problem is that direct measurements of our climate (for example, temperature) extend back no further than the past few hundred years, so such information must instead be reconstructed from so-called proxies, or 'substitutes'. Corals are particularly useful proxies, because they can be accurately dated and their chemical composition reflects a number of important environmental parameters, such as the temperature of the water in which they grew. Here, we propose to obtain records of the variation in the chemical composition of coral skeletons from Tahiti that are between 20 000 and 10 000 years old. What is unique, is that we will use new laser technology that enables us to obtain records at extremely high resolution (a few days to a few months). This means that we will be able to capture the short-term events that can influence the transition from glacial to warmer conditions on Earth.