Stable isotope compositions of biologically cycled elements encode information about the interaction between life and environment. On Earth, geochemical biomarkers have been used to probe the extent, nature, and activity of modern and ancient organisms. However, extracting biological information from stable isotopic compositions requires untangling the interconnected nature of the Earth’s biogeochemical system, and must be viewed through the lens of evolving metabolisms on an evolving planet. In this chapter, we provide an introduction to isotope geobiology and to the geobiological history of Earth. We discuss the isotope biogeochemistry of the biologically essential elements carbon, nitrogen and sulfur, and we summarize their distribution on the modern Earth as an interconnected network of isotopically fractionated reservoirs with contrasting residence times. We show how this framework can be used to explore the evolution of life and environments on the ancient Earth, which is our closest accessible analogue for an extraterrestrial planet.

中文翻译：

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不断演化的星球上生命的同位素印记

生物循环元素的稳定同位素组成编码有关生命与环境之间相互作用的信息。在地球上，地球化学生物标志物已被用于探测现代和古代生物的范围、性质和活动。然而，从稳定的同位素组成中提取生物信息需要解开地球生物地球化学系统相互关联的本质，并且必须通过不断进化的星球上不断进化的新陈代谢来看待。在本章中，我们将介绍同位素地球生物学和地球的地球生物学历史。我们讨论了生物必需元素碳、氮和硫的同位素生物地球化学，我们将它们在现代地球上的分布总结为具有不同停留时间的同位素分馏储层的互连网络。我们展示了如何使用这个框架来探索古代地球上生命和环境的演变，这是我们最接近地外行星的类似物。