A biomarker goldmine in Wilkes Land, Antarctica: nuggets from the Eocene Greenhouse (BIGWIG).

对一般公众的总结：综合大洋钻探计划第318次南极洲威尔克斯陆缘考察的目的是破译南极洲的长期气候和环境：从冰川前的温室世界，到东南极冰盖多次增长和崩溃的历史以及相关的海平面变化。探险队使用专业钻探船Joides Resolution来恢复深海沉积物。南极大陆的岩石和土壤不断受到侵蚀，这些沉积物在深海的接受环境中沉积下来，在那里沉积物可以一层又一层地不受干扰地连续沉积下来。这些沉积物是过去环境和海洋变化的信息库。在IODP 318考察队获得的沉积岩芯中发现了丰富的有机分子化石（生物标志物）和有机壁微体化石。某些化合物（特别是脂类）非常耐腐，因此在生产生物体死亡后，生物标志物被保存在沉积物中。这些生物标志物可以被提取、测量并用于重建数千年至数百万年间海洋和陆地温度等参数的变化;使我们能够定量重建过去气候和环境的变化。在IODP 318考察队中，这些化石最丰富的是可追溯到南极洲冰盖出现之前的温室时期（始新世早期，距今4800万至5500万年）的核心。生物标志物化石和有机壁微体化石的存在为研究关键的早始新世时期的冰前南极提供了一个独特的机会，该时期的特点是高大气CO2和全球平均温度达到长期最高值。此外，叠加在这种长期温暖之上的是一系列相对快速（不到数万年）的极端温暖事件，称为高温。我们将结合联合收割机最先进的分子有机生物标志物技术和孢粉学（有机壁微体化石）分析，以高分辨率重建陆地和海洋温度、大气CO2、碳循环变化、陆地蒸发/降水、海洋生产力和盐度的变化。对这一温室时期和超高温事件的研究至关重要，因为自工业化以来，大气中的二氧化碳浓度已经增长到高于过去200万年的任何时候。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）的浓度显着增加。如果排放量继续不减，到2035年，与工业化前时期相比，大气中的二氧化碳含量将增加一倍（550 ppm CO2 e）。换句话说，从大气层的角度来看，我们正在迅速回到始新世时期，在此期间，地球更温暖，行星冰量要低得多，海平面要比现在高得多。我们申请资金，使PI James Bendle能够协调项目团队并领导多代理分子生物标志物分析。如果英国科学要利用IODP 318暂停期（2011年6月到期）的竞争优势，那么2010年4月NERC UK-IODP电话的资金对于促进我们提出的分析和结果至关重要。

Summary for General Public: The aim of Integrated Ocean Drilling Programme (IODP) expedition 318, to the Wilkes Land margin of Antarctica, is to decipher the long-term climate and environmental Antarctica: from the pre-glacial Greenhouse world, through the history of multiple growth and collapse of the East Antarctic Ice Sheet (EAIS) and related sea-level changes. The expedition used the specialist drill ship, the Joides Resolution, to recover deep sea sediments. 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. Abundant organic molecular fossils (biomarkers) and organic walled microfossils were found in the sediment cores recovered by the IODP 318 expedition. 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. In expedition IODP 318 these fossils are most abundant is cores dating from the Greenhouse period before ice-sheets were present on Antarctica (the Early Eocene Period, 48 to 55 million years before the present). The presence of the biomarker fossils and organic walled microfossils offers a unique opportunity to study the pre-glacial Antarctic during the critical Early Eocene period, which was characterised by high atmospheric CO2 and mean global temperatures that reached a long-term maximum. Moreover, superimposed on this long-term warmth were a series of relatively rapid (less than a few tens of thousands of years), extreme warm events known as hyperthermals. We will combine state-of-the-art molecular organic biomarker techniques and palynological (organic-walled microfossils) analyses to reconstruct, at high-resolution, changes in land and sea temperatures, atmospheric CO2, carbon cycle changes, terrestrial evaporation/precipitation, marine productivity and salinity. Study of this Greenhouse period and the hyperthermal events is crucial because, since industrialisation, atmospheric concentrations of CO2 have grown to be 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 towards the Eocene period during which the planet was warmer, planetary ice volumes were much lower and sea-levels much higher than present. We request funding which will allow the PI, James Bendle to co-ordinate project team and lead in the multi-proxy, molecular biomarker analyses. If UK science is to take competitive advantage of the IODP 318 moratorium period (which expires in June 2011), then funding from the April 2010 NERC UK-IODP call is critical to facilitate our proposed analyses and outcomes.