Phosphorus (P) is typically considered to be the ultimate limiting nutrient for Earth's biosphere on geologic timescales. As P is monoisotopic, its sedimentary enrichment can provide some insights into how the marine P cycle has changed through time. A previous compilation of shale P enrichments argued for a significant change in P cycling during the Ediacaran Period (635–541 Ma). Here, using an updated P compilation—with more than twice the number of samples—we bolster the case that there was a significant transition in P cycling moving from the Precambrian into the Phanerozoic. However, our analysis suggests this state change may have occurred earlier than previously suggested. Specifically in the updated database, there is evidence for a transition ~35 million years before the onset of the Sturtian Snowball Earth glaciation in the Visingsö Group, potentially divorcing the climatic upheavals of the Neoproterozoic from changes in the Earth's P cycle. We attribute the transition in Earth's sedimentary P record to the onset of a more modern-like Earth system state characterized by less reducing marine conditions, higher marine P concentrations, and a greater predominance of eukaryotic organisms encompassing both primary producers and consumers. This view is consistent with organic biomarker evidence for a significant eukaryotic contribution to the preserved sedimentary organic matter in this succession and other contemporaneous Tonian marine sedimentary rocks. However, we stress that, even with an expanded dataset, we are likely far from pinpointing exactly when this transition occurred or whether Earth's history is characterized by a single or multiple transitions in the P cycle.

中文翻译：

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全球海洋磷循环演变的沉积记录

磷 (P) 通常被认为是地质时间尺度上地球生物圈的最终限制性营养素。由于 P 是单同位素的，因此其沉积富集可以为了解海洋 P 循环如何随时间变化提供一些见解。先前的页岩磷富集汇编认为埃迪卡拉纪 (635–541 Ma) 期间磷循环发生了显着变化。在这里，使用更新的 P 汇编（样本数量是原来的两倍多），我们支持了 P 循环从前寒武纪到显生宙的显着转变的情况。然而，我们的分析表明这种状态变化可能比之前建议的更早发生。特别是在更新的数据库中，有证据表明，在 Visingsö 群的 Sturtian Snowball Earth 冰川作用开始前约 3500 万年发生了转变，这可能使新元古代的气候剧变与地球 P 循环的变化脱节。我们将地球沉积 P 记录的转变归因于更现代的地球系统状态的开始，其特征是海洋条件减少、海洋 P 浓度升高以及包含初级生产者和消费者的真核生物占主导地位。这一观点与有机生物标志物证据一致，表明真核生物对这一层序和其他同期 Tonian 海相沉积岩中保存的沉积有机质有重要贡献。然而，我们强调，即使有一个扩展的数据集，