Source data for "Volcanic ash drives contrasting redox shifts and biogeochemical feedbacks in ancient marine and lacustrine systems"

Volcanic eruptions are major perturbations to Earth's biogeochemical cycles, yet their long-term effects on nutrient dynamics and ecosystem recovery remain unclear. Here we present high-resolution geochemical records from Late Ordovician marine and Middle Triassic lacustrine successions to investigate how airborne volcanic ash influenced carbon and nitrogen cycling. Our results reveal that volcanic ash deposition triggered contrasting redox responses in marine and lacustrine systems. In marine systems, ash input promoted persistent anoxia, suppressed nitrogen cycling, and delayed ecosystem recovery for millennia, and was further amplified by enrichment in toxic elements. In lacustrine systems, ash enhanced water-column oxygenation, reduced toxic stress, which stimulated nitrogen fixation and the growth of cyanobacteria, facilitating ecological recovery within decades. These findings demonstrate that volcanic ash drives contrasting biogeochemical responses in marine and lacustrine ecosystems, provide mechanistic insights into past ecosystem resilience, and offer a framework for predicting recovery under future volcanic and climatic disturbances.

火山喷发是地球生物地球化学循环的重大扰动事件，但其对营养盐动态与生态系统恢复的长期效应仍不明朗。本研究获取了晚奥陶世（Ordovician）海相与中三叠世（Triassic）湖相沉积序列的高分辨率地球化学记录，以此探究大气火山灰对碳循环与氮循环（nitrogen cycling）的影响。研究结果显示，火山灰沉降在海相与湖相系统中引发了截然不同的氧化还原（redox）响应：在海相系统中，火山灰输入促进了持续性缺氧（anoxia），抑制了氮循环，并使生态系统恢复延迟了数千年，且有毒元素富集进一步加剧了这一过程；在湖相系统中，火山灰提升了水体氧合水平，降低了有毒胁迫，进而刺激了固氮作用与蓝细菌（cyanobacteria）的生长，推动生态系统在数十年内完成恢复。本研究结果表明，火山灰在海相与湖相生态系统中引发了截然不同的生物地球化学响应，为理解古生态系统恢复力提供了机制性认识，并为预测未来火山与气候扰动下的生态恢复提供了理论框架。