Phosphorus is a limiting nutrient that is thought to control oceanic oxygen levels to a large extent^1,2,3. A possible increase in marine phosphorus concentrations during the Ediacaran Period (about 635–539 million years ago) has been proposed as a driver for increasing oxygen levels^4,5,6. However, little is known about the nature and evolution of phosphorus cycling during this time⁴. Here we use carbonate-associated phosphate (CAP) from six globally distributed sections to reconstruct oceanic phosphorus concentrations during a large negative carbon-isotope excursion—the Shuram excursion (SE)—which co-occurred with global oceanic oxygenation^7,8,9. Our data suggest pulsed increases in oceanic phosphorus concentrations during the falling and rising limbs of the SE. Using a quantitative biogeochemical model, we propose that this observation could be explained by carbon dioxide and phosphorus release from marine organic-matter oxidation primarily by sulfate, with further phosphorus release from carbon-dioxide-driven weathering on land. Collectively, this may have resulted in elevated organic-pyrite burial and ocean oxygenation. Our CAP data also seem to suggest equivalent oceanic phosphorus concentrations under maximum and minimum extents of ocean anoxia across the SE. This observation may reflect decoupled phosphorus and ocean anoxia cycles, as opposed to their coupled nature in the modern ocean. Our findings point to external stimuli such as sulfate weathering rather than internal oceanic phosphorus–oxygen cycling alone as a possible control on oceanic oxygenation in the Ediacaran. In turn, this may help explain the prolonged rise of atmospheric oxygen levels.

磷是一种限制性营养素，被认为可以在很大程度上控制海洋氧气水平^1,2,3。埃迪卡拉时期（约 635-5.39 亿年前）海洋磷浓度可能增加，有人提出这是氧气水平增加的驱动因素^4,5,6。然而，人们对这段时间内磷循环的性质和演变知之甚少⁴。在这里，我们使用来自全球分布的六个剖面的碳酸盐相关磷酸盐 (CAP) 来重建大型负碳同位素偏移（Shuram 偏移 (SE)）期间的海洋磷浓度，该偏移与全球海洋氧化同时发生^7,8,9。我们的数据表明，在东南部下降和上升期间，海洋磷浓度呈脉冲式增加。使用定量生物地球化学模型，我们提出这一观察结果可以通过海洋有机物主要通过硫酸盐氧化而释放的二氧化碳和磷来解释，以及二氧化碳驱动的陆地风化作用进一步释放磷。总的来说，这可能导致有机黄铁矿埋藏和海洋氧化增加。我们的 CAP 数据似乎还表明，在东南部海洋缺氧最大和最小程度下，海洋磷浓度相当。这一观察结果可能反映了磷和海洋缺氧循环的解耦，而不是它们在现代海洋中的耦合性质。我们的研究结果表明，外部刺激（例如硫酸盐风化）而不是内部海洋磷-氧循环本身可以作为埃迪卡拉纪海洋氧化的可能控制因素。反过来，这可能有助于解释大气中氧气水平的长期上升。