IODP 318 Wilkes Land Expedition participant (sailing)

公众摘要：人类活动正在改变地球的大气成分。自工业化以来，大气中二氧化碳的浓度已经增长到远远超过过去65万年（kyr）的自然范围，这是由冰芯数据观测到的。事实上，大气中目前的二氧化碳含量（380ppm）可能比过去200万年的任何时候都要高。在同一时期，由于人类活动，其他温室气体（温室气体：甲烷、氧化亚氮等）的浓度显著增加。如果排放继续不减，到2035年，大气中的二氧化碳含量将比工业化前时期增加一倍（二氧化碳当量为550 ppm）。换句话说，从大气的角度来看，我们正迅速回到新生代（过去6550万年），在这个时期，地球比现在更温暖，行星冰量要少得多，海平面要高得多。作为对温室气体水平上升的回应，预计未来100年全球平均气温将上升1.1-6.4摄氏度。从时间上看，预测温度范围的最低点最后一次出现在距今120kyr的末次间冰期，但大部分温度范围（2 ~ 6.4*C）自3500万~ 5000万年前（渐新世和始新世）以来没有出现过。在此期间，地球太热，无法维持北半球或南半球的大冰原。这引起了人们对南极冰未来稳定性的担忧，南极冰有可能使全球海平面上升60米。气候模式本身无法精确地定义气候敏感性，因为很难证明模式实际地包含所有反馈过程（可以放大变化的过程）。古气候数据的内在价值在于它包含了较慢的反馈（冰的变化、反照率等）。因此，研究过去5000万年南极冰的行为是至关重要的，这为测试冰盖和气候行为模型提供了基础事实。“综合海洋钻探计划”（IODP）第318次考察队前往南大洋的威尔克斯陆缘，目的是破译南极东部冰盖（EAIS）多次生长和崩塌的长期历史，以及相关的海平面变化、古海洋学和古环境变化。另一个目标是恢复每年的层状沉积物，以建立全新世时期（过去10kyr）最近气候变化的超高分辨率记录。探险队将使用专业钻探船“乔迪斯决议号”从威尔克斯陆缘回收深海沉积物。南极大陆的岩石和土壤受到持续的侵蚀，这些沉积物沉积在深海的接受环境中，在那里，沉积层一层接一层的沉积层可以不受干扰地连续沉积。这些沉积物是过去环境和海洋学变化的信息库。IODP 318考察队回收的沉积物岩心将含有有机分子化石（生物标志物）。某些化合物（尤其是脂类）具有很强的抗腐性，因此在生产生物体过期后，生物标记物被保存在沉积物中。这些生物标记物可以被提取、测量并用于重建参数的变化，如海洋和陆地温度在数千年至数百万年间的变化；使我们能够定量地重建过去气候和环境的变化，并将其与冰盖体积和海平面的变化联系起来。首席研究员将参加Wilkes Land 318考察，并将与国际科学团队的其他成员密切合作。该提案的目的是为格拉斯哥生物标志物的探险后提取和测量提供资金。

Summary for General Public: Human activities are altering Earth's atmospheric composition. Since industrialisation, atmospheric concentrations of CO2 have grown to exceed by far the natural range of the last 650 thousand years (kyr), observed in ice core data. In fact it's probable that the current level of CO2 (380ppm) in the atmosphere is higher now than at any time in the last 2 million years (Myr). Over the same period, concentrations of other greenhouse gasses (GHGs: methane, nitrous oxides etc) have increased markedly due to human activity. If emissions continue unabated, by 2035 we will have effectively doubled the amount of carbon dioxide in the atmosphere (550 ppm CO2e), compared to the preindustrial period. In other words, atmospherically speaking, we are rapidly heading back into the Cenazoic era (the past 65.5 million years), during which the planet was warmer, planetary ice volumes were much lower and sea-levels higher than present. In response to rising levels of GHGs, average planetary temperature is expected to rise by between 1.1-6.4*C in the next 100 years. Looking back in time, the lowest point on the predicted temperature range was last experienced during the last interglacial, 120 kyr before present, but most of the range (2 to 6.4*C) has not been experienced since the period between 35 and 50 million years ago (the Oligocene and Eocene eras). During this period the planet was too warm to sustain large ice sheets in the Northern or Southern Hemispheres. This has given rise to concerns about the future stability of the Antarctic Ice, which have the potential to raise global sea levels by 60m. Climate models alone are unable to define climate sensitivity precisely, because it is difficult to prove that models realistically incorporate all feedback processes (processes which can amplify change). An intrinsic value of palaeoclimate data is that it includes slower feedbacks (changes in ice, albedo etc). Therefore it is vital to investigate the behaviour of Antarctic Ice over the last 50 million years, to provide ground truth for testing models of ice sheet and climate behaviour. The aim of Integrated Ocean Drilling Programme (IODP) expedition 318, to the Wilkes Land margin in the Southern Ocean, is to decipher the long-term history of multiple growth and collapse of the East Antarctic Ice Sheet (EAIS), related sea-level changes and palaeoceanographic and palaeoenvironmental changes. An additional aim is to recover annually laminated sediments to develop an ultra-high resolution record of recent climate variability during the Holocene period (the last 10kyr). The expedition will use the specialist drill ship, the Joides Resolution, to recover deep sea sediments from the Wilkes Land margin. There has been a continuous process of erosion of rocks and soils from the Antarctic continent and deposition of these sediments in the receptive environment of the deep ocean, where layer upon layer of sediment can be laid down in undisturbed succession. These sediments are a repository of information on past environmental and oceanographic changes. The sediment cores recovered by the IODP 318 expedition will contain organic molecular fossils (biomarkers). Certain compounds (especially lipids) are quite resistant to decay, so after the producer organisms expire, the biomarkers are preserved in sediments. These biomarkers can be extracted, measured and used to reconstruct changes in parameters such ocean and land temperature over thousands to millions of years; allowing us to quantitatively reconstruct past changes in climate and environments and to relate this to changes in ice-sheet volume and sea-level. The principal investigator will participate on the Wilkes Land 318 expedition and will work in close collaboration with the other members of the international scientific party. The purpose of this proposal is to fund post-expedition extraction and measurement of biomarkers in Glasgow.