Co-Evolution of Precambrian Life and the Environment

在整个地球历史中，海水中微量元素的可用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，以及促进氧化风化反应的大气氧气的间断积累。这些事件可能在数十亿年的时间里指导了微生物在酶水平上的进化，这一想法相对较新，但意义深远，因为微生物的创新最终决定了地球对随后出现的更复杂生物的宜居性。我目前的大部分研究项目集中在解决深层地质时代的海水成分，目的是更好地了解地球前寒武纪环境和生物圈的共同进化。这项研究的基础将是实地研究和实验室研究的结合。野外部分包括三种对比海洋沉积物的收集和分析；(i)带状铁地层；（ii）黑色页岩；（iii）叠层石碳酸盐岩。每一种岩性都被单独成功地用于破译海水成分的时间变化。然而，以前从未尝试过整合数据集，以提供古营养景观的全面图景，就像今天一样，古营养景观应该沿着海洋样带变化。我将重点关注两个特定的时间间隔：(1)生命开始进化的太古宙（4.0-3.7 Ga）和(2)地球第一次成为含氧的新太古代-古元古代（2.7-2.3 Ga）。实验室部分将侧重于设计实验以补充这些实地研究。具体而言，我的目标是：(i)确定古代海洋浮游生物如何在金属浓度升高和致命紫外线辐射的海洋中生存；（ii）结合使用地球化学建模、蛋白质组学和基因组学来阐明生物活性金属在细菌金属酶起源中的重要性；（iii）通过同步辐射技术完善现有的络合模型，以确定微量金属被原生BIF矿物和叠层石吸收的分子机制，从而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.