Bridging the timing gap: connecting Southern Ocean and Antarctic Climate records

缩小时间差距：连接南大洋和南极气候记录

基本信息

批准号：
NE/N003861/1
负责人：
Laura Robinson
金额：
$ 52.85万
依托单位：
University of Bristol
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2015
资助国家：
英国
起止时间：
2015 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FN003861%2F1
关键词：
Bridging timing gap connecting Southern

项目摘要

In light of current concerns over greenhouse-gas emissions and related temperature rise it is important to understand the mechanisms operating in the global climate system. This understanding may allow us to anticipate human-induced climate change and related ecosystem vulnerability. The Southern Ocean plays a central role in defining Earth's climate because it is a location where cold, deep waters rise to the surface and exchange gases and heat with the atmosphere. One of the most important gases for the climate system is carbon dioxide (CO2). Since the oceans contain about 60 times more carbon than the atmosphere, it only takes a small perturbation in the ocean to have a large climate impact. Atmospheric CO2 levels have shown systematic changes over the past 800,000 years as revealed by gasses trapped in ice cores, and recent evidence has come to light that shows that CO2 can increase rapidly over only hundreds of years. We still do not know how and why these changes in CO2 occur but their size and speed suggests that they must have been driven by changes in the deep ocean.Mechanisms that have been put forward to explain lower atmospheric CO2 concentrations during past cold (glacial) periods focus on increased CO2 uptake in the Southern Ocean. This could have been achieved by a combination of increased sea ice cover and a more layered structure in the water column, which prevents CO2 from escaping to the atmosphere. The concept is supported by modeling evidence and predicts that we should find old, carbon-rich waters in the deep Southern Ocean during past cold times. If this layered water structure was removed, then these deep waters would release CO2 to the atmosphere as ice ages came to a close. Records from ice cores show us that the actual rise of CO2 during the end of the last ice age ('last deglaciation') happened in multiple steps. So far, however, it has been very difficult to obtain records from the Southern Ocean to test the hypothesis posed above, or the alternative hypothesis that carbon sequestration in the South was achieved due to more active CO2 uptake by planktonic marine plants. What we have been lacking is a suitable recorder ('archive') of past environmental conditions directly in the Southern Ocean that can resolve time increments of about 100 years or less, similar to in the record preserved in ice cores.With our project we aim to transform understanding of the Southern Ocean's role in climate change by creating detailed records of the circulation, temperature, and CO2 chemistry of the Southern Ocean at the end of the last ice age and into the current warm period (past 25,000 years) at unprecedented temporal resolution. To achieve this we will make geochemical measurements on the skeletons of fossil deep-sea corals, a novel archive that allows us to create unique coupled records of past oceanographic change on a precise and accurate timescale. The skeletons of deep-sea corals are formed using the chemical ingredients of the seawater that they live in. This means that during the lifetime of a coral (~100 years) a record of water mass composition and temperature is captured as they grow. By performing a suite of geochemical measurements on each fossil coral, we can reconstruct environmental conditions at the time it grew. Repeating this exercise for hundreds of corals will allow us to construct the first directly dated record of the Southern Ocean's behavior since the last ice age. Our new record will allow comparison of the relative timing of environmental changes in the Southern Ocean with those of ice core records. It will therefore address one of the most hotly debated questions in global climate change research, the origin of changes in atmospheric CO2 and temperature on time scales of hundreds to thousands of years.

鉴于目前对温室气体排放和相关温度升高的关注，了解全球气候系统中运行的机制很重要。这种理解可能使我们能够预测人类引起的气候变化和相关的生态系统脆弱性。南方海洋在定义地球气候方面起着核心作用，因为它是一个冷水升至地面并与大气交换气体和热量的地方。气候系统最重要的气体之一是二氧化碳（CO2）。由于海洋的碳含量是大气的60倍，因此在海洋中只需要少量扰动就能产生巨大的气候影响。大气二氧化碳水平已经显示出过去80万年的系统变化，如被困在冰芯中的气体所揭示的那样，最近有证据表明，表明二氧化碳只能在数百年中迅速增加。我们仍然不知道二氧化碳中的这些变化是如何以及为什么发生的，但是它们的大小和速度表明它们一定是由深海的变化驱动的。在寒冷（冰川）期间（冰川）时期提出了较低的大气二氧化碳浓度的驱动。这可以通过在水柱中增加海冰盖和更分层的结构的结合来实现这一目标，从而防止二氧化碳逃脱到大气中。该概念是通过建模证据来支持的，并预测我们应该在过去的寒冷时期发现南部深海深海水域。如果去除了这种分层的水结构，那么随着冰河年龄结束，这些深水将释放到大气中。冰芯的记录表明，在最后一个冰河时代结束时，二氧化碳的实际升高（“最后一次脱气”）发生了多个步骤。然而，到目前为止，很难从南大洋中获得记录来检验上面提出的假设，或者是由于浮游海洋植物的更活跃的二氧化碳吸收而获得了南方的碳固存。我们所缺乏的是南大洋过去的一个适当的录音机（“档案”），可以解决大约100年或更短的时间增量，类似于保存在冰芯中的记录中。我们的项目旨在改变对南方海洋在气候变化中的理解的理解，从而通过创造了循环，温度和CO2年龄的详细记录，并在当前的ICE时代及时，在当前的ICE时代，并在当前的CO2年度中，并在当前的CO2化学中（过去），并在当前的CO2化学中（过去），并在当前的CO2年度中，并在当前的CO2年度中，并在当前的CO2年度中，以及在当前的冰期变化，并在当前的CO2年度中，并在当前的CO2年度中，并在当前的CO2年度中，并在当前的CO2年度中，并在当前的CO2年代播放了一场冰期变化。空前的时间分辨率。为了实现这一目标，我们将对化石深海珊瑚的骨骼进行地球化学测量，这是一个新颖的档案，使我们能够在精确而准确的时间表上创建过去海洋学变化的独特耦合记录。深海珊瑚的骨骼是使用它们所居住的海水的化学成分形成的。这意味着在珊瑚（〜100年）的一生中，水质量成分和温度随着它们生长而捕获。通过对每个化石珊瑚进行一系列地球化学测量，我们可以在生长时重建环境条件。重复数百种珊瑚的练习将使我们能够构建自上次冰河时代以来南大洋行为的第一个直接日期的记录。我们的新记录将允许将南洋环境变化的相对时机与冰核记录的相对时机进行比较。因此，它将解决全球气候变化研究中最激烈的争论问题之一，大气二氧化碳变化的起源和数百至数千年的时间尺度的起源。

项目成果

期刊论文数量（10）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Acceleration of Northern Ice Sheet Melt Induces AMOC Slowdown and Northern Cooling in Simulations of the Early Last Deglaciation

DOI：
10.1029/2017pa003308
发表时间：
2018-07
期刊：
Paleoceanography and Paleoclimatology
影响因子：
3.5
作者：
R. Ivanović;L. Gregoire;Andrea Burke;A. Wickert;Paul J. Valdes;H. C. Ng;Laura F. Robinson;Jerry F. McManus;J. Mitrovica;Lindsay Lee;J. Dentith
通讯作者：
R. Ivanović;L. Gregoire;Andrea Burke;A. Wickert;Paul J. Valdes;H. C. Ng;Laura F. Robinson;Jerry F. McManus;J. Mitrovica;Lindsay Lee;J. Dentith

Rapid shifts in circulation and biogeochemistry of the Southern Ocean during deglacial carbon cycle events.

DOI：
10.1126/sciadv.abb3807
发表时间：
2020-10
期刊：
Science advances
影响因子：
13.6
作者：
Li T;Robinson LF;Chen T;Wang XT;Burke A;Rae JWB;Pegrum-Haram A;Knowles TDJ;Li G;Chen J;Ng HC;Prokopenko M;Rowland GH;Samperiz A;Stewart JA;Southon J;Spooner PT
通讯作者：
Spooner PT

Ba/Ca of stylasterid coral skeletons records dissolved seawater barium concentrations