The Late Ordovician−Early Silurian is a convergence period of multiple events in geological history, including dramatic variations of biology, environment, and geology. Extensive research has demonstrated remarkable fluctuations in ocean chemistry, microbial ecosystems, and biogeochemical elemental cycles experienced. However, the spatial-temporal evaluation of marine primary productivity and its links to organic matter accumulation during this key period remain elusive. Here, we present high-resolution marine primary productivity proxy (organic carbon accumulation rates: OCAR) and geochemical data from the Fengtonggang and Qiliao sections deposited in South China and adopted numerous other coeval sections of geochemical data globally, to improve the understanding of these fundamental scientific questions. The results show that all statistical profiles presented broadly high marine primary productivity before and after the Hirnantian glaciation maximum and low values during the glaciation, and a maximum marine primary productivity typically recorded at the uppermost part of the P.pacificus Zone. The C_org/P_total ratios indicate that oceanic anoxia was ubiquitous during the Late Katian to Early Rhuddanian, but strong spatial heterogeneous during the Hirnantian glaciation maximum. The volcanism and nitrogen availability may have played an important role in regulating the variations of marine primary productivity globally. Besides, redox-controlled phosphorus cycling may have also exerted a remarkable influence on marine primary productivity. The high C_org/P_total ratios (exceed the Redfield ratio of 106/1) observed in the Wufeng and Longmaxi formations indicate that phosphorus was recycled effectively back to the water column, promoting a positive productivity feedback. By contrast, the low C_org/P_total ratios found in the Guanyinqiao Bed reflect phosphorus retention in the sediment, limiting phosphorus recycling back to the water column, consequently restricting the primary production. The enhanced marine primary productivity resulted from nutrient regeneration, ocean anoxia, and high sea level may have led to high organic carbon export and preservation. The consistency between the highest marine primary productivity and the first pulse of mass extinction suggests that eutrophication-induced marine anoxia may have played an essential killing mechanism during the first Late Ordovician mass extinction.

晚奥陶世-早志留世是地质历史上多个事件的汇合期，包括生物学、环境和地质的剧烈变化。广泛的研究表明，海洋化学、微生物生态系统和生物地球化学元素循环经历了显着的波动。然而，在这一关键时期，海洋初级生产力的时空评估及其与有机质积累的联系仍然难以捉摸。在这里，我们展示了来自华南地区丰通港和七辽剖面的高分辨率海洋初级生产力代理（有机碳积累率：OCAR）和地球化学数据，并采用了全球许多其他同期地球化学剖面数据，以提高对这些基础知识的理解。科学问题。P.pacificus区。C _org / P_总比值表明，在晚Katian到早Rhuddanian期间海洋缺氧普遍存在，但在Hirnantian冰川最大期间存在强烈的空间异质性。火山活动和氮的有效性可能在调节全球海洋初级生产力的变化方面发挥了重要作用。此外，氧化还原控制的磷循环也可能对海洋初级生产力产生显着影响。在五峰组和龙马溪组观察到的高 C _org / P_总比率（超过 Redfield 比率 106/1）表明磷被有效地循环回水柱，促进了积极的生产力反馈。相比之下，低 C_{在观音桥床中发现的org} / P_总比率反映了沉积物中的磷滞留，限制了磷循环回水柱，从而限制了初级生产。养分再生、海洋缺氧和高海平面提高的海洋初级生产力可能导致高有机碳输出和保存。最高海洋初级生产力与第一次大规模灭绝脉冲之间的一致性表明，富营养化引起的海洋缺氧可能在第一次晚奥陶世大规模灭绝期间发挥了重要的杀伤机制。