IODP 318 Wilkes Land Expedition participant (sailing)

公众总结：人类活动正在改变地球的大气组成。自工业化以来，大气中的二氧化碳浓度已经远远超过了冰芯数据中观察到的过去650,000年(KYR)的自然范围。事实上，目前大气中的二氧化碳水平(380ppm)很可能比过去200万年来的任何时候(Myr)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、一氧化二氮等)的浓度显著增加。如果排放继续有增无减，到2035年，与前工业化时期相比，我们将有效地将大气中的二氧化碳数量(550ppm二氧化碳)增加一倍。换句话说，从大气层上讲，我们正在迅速回到塞纳佐夫时代(过去6550万年)，在此期间，地球变暖，行星冰量比现在低得多，海平面比现在高得多。为了应对温室气体水平的上升，预计未来100年全球平均气温将上升1.1-6.4摄氏度。回顾过去，预测温度范围的最低点上一次出现在最后一次间冰期，在此之前为120 KYR，但自3500万年前至5000万年前(渐新世和始新世)以来，大部分温度范围(2至6.4*C)都没有经历过。在此期间，地球温度太高，无法承受北半球或南半球的大冰盖。这引发了人们对南极冰层未来稳定性的担忧，南极冰层有可能使全球海平面上升60米。气候模型本身不能准确地定义气候敏感性，因为很难证明模型实际地包含了所有反馈过程(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，调查南极冰在过去5000万年中的行为，为测试冰盖和气候行为的模型提供地面真实情况是至关重要的。综合大洋钻探计划(IODP)对南大洋威尔克斯陆缘的318次考察的目的是破译东南极冰盖(EAIS)多重增长和崩溃的长期历史、相关的海平面变化以及古海洋学和古环境变化。另一个目标是恢复每年一次的层状沉积物，以开发全新世期间(最后10年)最近气候变化的超高分辨率记录。探险队将使用专业钻井船乔伊德斯决议号，从威尔克斯陆地边缘回收深海沉积物。南极大陆的岩石和土壤不断受到侵蚀，这些沉积物在深海接受环境中沉积，在那里可以不受干扰地层层堆积沉积物。这些沉积物是过去环境和海洋变化的信息储存库。IODP 318探险队发现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)很难腐烂，所以在生物产生体失效后，生物标志物会保存在沉积物中。这些生物标志物可以被提取、测量并用于重建海洋和陆地温度等参数在数千到数百万年间的变化；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。首席研究员将参加威尔克斯陆地318号探险，并将与国际科学党的其他成员密切合作。这项提议的目的是资助在格拉斯哥进行探险后生物标志物的提取和测量。

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.