The emergence of an aerobic world: isotopic evidence for biogeochemical changes at the Archean-Proterozoic transition

毫无疑问，新太古代晚期和古元古代早期是地球历史上的一个时间窗口，在那里我们的星球经历了最不寻常的环境变化：大气中氧气的第一次主要上升，可能将现有的生物化学从厌氧变为有氧。这个时间点，被称为大氧化事件，标志着位于地球表面的环境中有氧条件的开始。厌氧过程从表层沃茨消失，进入静止缺氧的深层沃茨和/或沉积物。因此，海洋生物化学逐渐类似于现代有氧世界，特别是在有机物质的再循环方面。由于大陆的氧化风化作用，海洋硫酸盐丰度增加，从而抵消了大气氧含量的增加。反过来，海洋硫酸盐水平的增加肯定会通过硫酸盐还原刺激其微生物周转，随后可能会出现其他形式的微生物硫循环。该时间间隔的详细硫同位素记录将记录在不断变化的环境条件下硫代谢日益重要的情况。

Undoubtedly, the late Neoarchean and early Paleoproterozoic is a time window in Earth history, where our planet experienced a most extraordinary environmental change: the first major rise in atmospheric oxygen, likely changing existing biochemistries from anaerobic to aerobic. This point in time, termed the Great Oxidation Event, marks the onset of aerobic conditions in environments located at the Earth’s surface. Anaerobic processes vanished from the surface waters into still anoxic deep waters and/or into the sediment. Consequently, oceanic biochemistry progressively resembled that of the modern aerobic world, particular with respect to the recycling of organic matter. The rise in atmospheric oxygen was paralleled by an increase in oceanic sulphate abundance as a consequence of oxidative weathering on the continents. An increasing level of oceanic sulphate, in turn, must have stimulated its microbial turnover via sulphate reduction, with other forms of microbial sulphur cycling that likely followed. A detailed sulphur isotope record for this time interval will document this increasing importance of sulphur metabolism under changing environmental conditions.