二叠纪-三叠纪灭绝事件
生物集群灭绝
营养物
二叠纪
海洋学
环境科学
地质学
消光(光学矿物学)
生态学
古生物学
生物
生物扩散
构造盆地
社会学
人口学
人口
作者
Martin Schobben,William Foster,Arve Sleveland,Valentin Zuchuat,Henrik Svensen,Sverre Planke,David Bond,Fons Marcelis,Robert U. Newton,Paul B. Wignall,Simon W. Poulton
标识
DOI:10.1038/s41561-020-0622-1
摘要
Oxygen deprivation and hydrogen sulfide toxicity are considered potent kill mechanisms during the mass extinction just before the Permian–Triassic boundary (~251.9 million years ago). However, the mechanism that drove vast stretches of the ocean to an anoxic state is unclear. Here, we present palaeoredox and phosphorus speciation data for a marine bathymetric transect from Svalbard. This shows that, before the extinction, enhanced weathering driven by Siberian Traps volcanism increased the influx of phosphorus, thus enhancing marine primary productivity and oxygen depletion in proximal shelf settings. However, this non-sulfidic state efficiently sequestered phosphorus in the sediment in association with iron minerals, thus restricting the intensity and spatial extent of oxygen-depleted waters. The collapse of vegetation on land immediately before the marine extinction changed the relative weathering influx of iron and sulfate. The resulting transition to euxinic (sulfidic) conditions led to enhanced remobilization of bioavailable phosphorus, initiating a feedback that caused the spread of anoxic waters across large portions of the shelf. This reconciles a lag of >0.3 million years between the onset of enhanced weathering and the development of widespread, but geographically variable, ocean anoxia, with major implications for extinction selectivity. Phosphorus remobilized from seafloor sediments due to a reduced influx of iron-oxide from land led to widespread anoxia during the end-Permian mass extinction, according to palaeoredox and phosphorus speciation proxy records from Svalbard.
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