Co-Evolution of Precambrian Life and the Environment

纵观地球历史，海水中痕量元素的有效性一直受到长期地质过程的控制，例如上地幔的逐渐冷却，火山活动和大陆成分的变化，以及大气中氧气的间歇性积累，从而促进了氧化风化反应。这些事件可能在数十亿年的酶水平上引导了微生物进化的想法是相对较新的，但意义深远，因为微生物创新最终决定了地球对随后更复杂的有机体的宜居性。我目前的大部分研究计划都集中在解决深部地质时代的海水成分问题上，目的是更好地了解地球前寒武纪环境和生物圈的共同演化。这项研究的基础将是实地研究和实验室研究的结合。野外部分包括收集和分析三种截然不同的海洋沉积物：(I)条状铁建造、(Ii)黑色页岩和(Iii)叠层石碳酸盐。每种岩性都被单独用于破译海水成分的时间变化，并取得了巨大的成功。然而，以前从未尝试过的是整合数据集，以提供古营养景观的全面图景，就像今天一样，应该在海洋横断面上发生变化。我将集中讨论两个具体的时间间隔：(1)生命首次演化的始太古代(4.0-3.7Ga)，以及(2)新太古代-古元古代(2.7-2.3Ga)，当时地球第一次被氧化。实验室部分将专注于设计实验，以补充这些实地研究。具体地说，我的目标是：(1)确定古代海洋浮游生物如何在金属浓度升高和紫外线致命照射的海洋中生存下来；(2)利用地球化学模拟、蛋白质组学和基因组学相结合的方法，阐明生物活性金属在细菌金属酶起源中的重要性；以及(3)通过同步辐射技术改进现有的络合模型，以确定微量金属摄取到初级BIF矿物和叠层石的分子机制，以便校准我们的岩石记录数据。

Throughout Earth's history the availability of trace elements in seawater has been controlled by long-term geological processes, such as the gradual cooling of the upper mantle, changing styles of volcanism and continental composition, and the punctuated accumulation of atmospheric oxygen that fostered oxidative weathering reactions. The idea that these events may have directed microbial evolution at the enzymatic level over billions of years is relatively recent, but incredibly profound because microbiological innovations ultimately determined Earth's habitability for the more complex organisms that followed. Much of my current research programme is focused on resolving seawater composition in deep geological time, with an aim of better understanding of the co-evolution of Earth's Precambrian environment and biosphere. The basis for this research will be the coupling of field and laboratory studies. The field component consists of the collection and analyses of three contrasting marine sediments; (i) banded iron formations, (ii) black shales, and (iii) stromatolitic carbonates. Each lithology has individually been used with great success to decipher temporal variations in seawater composition. However, what has never been attempted before is an integration of datasets to provide a comprehensive picture of the paleo-nutrient landscape that, as today, should have varied along an ocean transect. I will focus on two specific time intervals: the (1) Eoarchean (4.0-3.7 Ga) when life first evolved, and (2) Neoarchean-Paleoproterozoic (2.7-2.3 Ga) when Earth first became oxygenated. The lab component will focus on designing experiments to compliment those field studies. Specifically, my goal is to (i) ascertain how ancient marine plankton survived in oceans with elevated metal concentrations and lethal influxes of ultraviolet radiation, (ii) use a combination of geochemical modelling, proteomics and genomics to elucidate the importance of bioactive metals in the origins of bacterial metallo-enzymes, and (iii) refine existing complexation models via synchrotron radiation techniques to determine the molecular mechanisms for trace metal uptake into primary BIF minerals and stromatolites in order to calibrate our rock record data.