Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, United States.
Department of Plant Biology, University of California, Davis, Davis, CA, United States; Department of Energy, Feedstocks Division, Joint BioEnergy Institute, Emeryville, CA, United States; Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States.
Free Radic Biol Med. 2019 Aug 20;140:188-199. doi: 10.1016/j.freeradbiomed.2019.01.049. Epub 2019 Feb 18.
The fixation of inorganic carbon species like CO to more reduced organic forms is one of the most fundamental processes of life as we know it. Although several carbon fixation pathways are known to exist, on Earth today nearly all global carbon fixation is driven by the Calvin cycle in oxygenic photosynthetic plants, algae, and Cyanobacteria. At other times in Earth history, other organisms utilizing different carbon fixation pathways may have played relatively larger roles, with this balance shifting over geological time as the environmental context of life has changed and evolutionary innovations accumulated. Among the most dramatic changes that our planet and the biosphere have undergone are those surrounding the rise of O in our atmosphere-first during the Great Oxygenation Event at ∼2.3 Ga, and perhaps again during Neoproterozoic or Paleozoic time. These oxygenation events likely represent major step changes in the tempo and mode of biological productivity as a result of the increased productivity of oxygenic photosynthesis and the introduction of O into geochemical and biological systems, and likely involved shifts in the relative contribution of different carbon fixation pathways. Here, we review what is known from both the rock record and comparative biology about the evolution of carbon fixation pathways, their contributions to primary productivity through time, and their relationship to the evolving oxygenation state of the fluid Earth following the evolution and expansion of oxygenic photosynthesis.
将无机碳物种（如 CO）固定到更还原的有机形式是我们所知的生命的最基本过程之一。尽管已知存在几种碳固定途径，但在当今地球上，几乎所有的全球碳固定都是由产氧光合作用植物、藻类和蓝细菌中的卡尔文循环驱动的。在地球历史的其他时期，利用不同碳固定途径的其他生物可能发挥了相对更大的作用，随着生命环境的变化和进化创新的积累，这种平衡在地质时间上发生了变化。我们的星球和生物圈经历的最显著变化之一是大气中氧气的增加——首先是在大约 23 亿年前的大氧化事件期间，也许在新元古代或古生代再次发生。这些氧化事件可能代表了生物生产力的节奏和模式的重大变化，这是由于产氧光合作用的生产力增加以及氧气进入地球化学和生物系统，并且可能涉及不同碳固定途径的相对贡献的变化。在这里，我们回顾了从岩石记录和比较生物学中了解到的有关碳固定途径的进化、它们对时间上初级生产力的贡献以及它们与产氧光合作用的进化和扩张后地球流体氧化状态演变的关系。
