School of Earth and Environments, University of Leeds, Leeds, LS2 9JT, UK.
State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, 430074, China.
Nat Commun. 2020 Jun 11;11(1):2962. doi: 10.1038/s41467-020-16725-4.
Records suggest that the Permo-Triassic mass extinction (PTME) involved one of the most severe terrestrial ecosystem collapses of the Phanerozoic. However, it has proved difficult to constrain the extent of the primary productivity loss on land, hindering our understanding of the effects on global biogeochemistry. We build a new biogeochemical model that couples the global Hg and C cycles to evaluate the distinct terrestrial contribution to atmosphere-ocean biogeochemistry separated from coeval volcanic fluxes. We show that the large short-lived Hg spike, and nadirs in δHg and δC values at the marine PTME are best explained by a sudden, massive pulse of terrestrial biomass oxidation, while volcanism remains an adequate explanation for the longer-term geochemical changes. Our modelling shows that a massive collapse of terrestrial ecosystems linked to volcanism-driven environmental change triggered significant biogeochemical changes, and cascaded organic matter, nutrients, Hg and other organically-bound species into the marine system.
记录表明，二叠纪-三叠纪大灭绝（PTME）涉及到显生宙时期最严重的陆地生态系统崩溃之一。然而，要限制陆地初级生产力的损失程度一直很困难，这阻碍了我们对其对全球生物地球化学影响的理解。我们构建了一个新的生物地球化学模型，将全球汞和碳循环耦合起来，以评估与同期火山通量分离的陆地对大气-海洋生物地球化学的独特贡献。我们表明，海洋 PTME 中汞的大而短暂的峰值以及汞和碳值的下降幅度，可以最好地解释为陆地生物质氧化的突然、大规模脉冲，而火山作用仍然是长期地球化学变化的充分解释。我们的模型表明，与火山驱动的环境变化相关的陆地生态系统的大规模崩溃引发了显著的生物地球化学变化，并将大量的有机物质、营养物质、汞和其他有机结合的物质带入海洋系统。
