Flourishing ocean drives the end-Permian marine mass extinction
Flourishing ocean drives the end-Permian marine mass extinction
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DOI：
10.1073/pnas.1503755112
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发表时间：
2015-08
期刊：
影响因子：
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通讯作者：
Martin Schobben;A. Stebbins;A. Ghaderi;H. Strauss;D. Korn;C. Korte
中科院分区：
文献类型：
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作者：
Martin Schobben;A. Stebbins;A. Ghaderi;H. Strauss;D. Korn;C. Korte
这项研究提供了地球化学证据，将一些与二叠纪末大规模灭绝相关的最重要发现联系起来，包括气候变暖，风化作用增强，初级生产力增加，以及普遍的海洋缺氧，这些发现都有一个共同点：相关的地球化学硫和碳循环。致命的海洋条件可能是气候反馈机制增加海洋营养输入的结果，从而刺激全球有机碳生产。考虑到未来预计的气候变化，这种气候反馈机制可能导致广泛的富营养化以及缺氧和硫化物区的扩大，从而从根本上改变海洋生态系统。二叠纪末生物大灭绝是中生代最严重的生物危机，伴随着气候变化和海洋缺氧带的扩张。硫在不同的外源水库之间的生物和物理过程的分配是重要的生物多样性危机，但生物必需硫在大灭绝的确切作用仍然不清楚。在这里，我们表明，全球有机物产量的增加影响了海水硫酸盐硫和氧同位素的签名，已记录在碳酸盐岩跨越二叠纪-三叠纪边界。一个分叉的时间趋势，观察到的地层跨越海洋生物大灭绝与碳酸盐相关的硫酸盐硫和氧同位素的漂移减少和增加的值，分别。通过将这些结果与箱形模型相结合，我们发现海洋生产力的提高和微生物硫酸盐还原的连续增强是解释这些时间趋势的最有可能的方案。新数据表明，全球缺氧区和缺氧区的扩张是全球变暖引发的海洋领域生物碳循环增加的症状。浅海底环境中硫化物水柱条件的空间分布取决于营养物通量的严重程度和地理格局，可作为解释海洋生物多样性危机规模的适当模型。我们的研究结果提供的证据表明，地球历史上主要的生物多样性危机并不一定意味着海洋被剥夺了（大多数）生命，而是某些真核生物的死亡，导致物种丰富度下降。
Significance This study provides geochemical evidence that links some of the most important finds associated with the end-Permian mass extinction, including climate warming, enhanced weathering, increased primary productivity, and widespread marine anoxia under a common denominator: the linked biogeochemical sulfur and carbon cycles. Lethal marine conditions are likely the result of climate feedback mechanisms acting to increase nutrient input to the ocean, thereby stimulating global organic carbon production. With future projected climate change in mind, such climate feedback mechanisms could induce widespread eutrophication and expansion of anoxic and sulfidic zones, thereby fundamentally altering marine ecosystems. The end-Permian mass extinction, the most severe biotic crisis in the Phanerozoic, was accompanied by climate change and expansion of oceanic anoxic zones. The partitioning of sulfur among different exogenic reservoirs by biological and physical processes was of importance for this biodiversity crisis, but the exact role of bioessential sulfur in the mass extinction is still unclear. Here we show that globally increased production of organic matter affected the seawater sulfate sulfur and oxygen isotope signature that has been recorded in carbonate rock spanning the Permian−Triassic boundary. A bifurcating temporal trend is observed for the strata spanning the marine mass extinction with carbonate-associated sulfate sulfur and oxygen isotope excursions toward decreased and increased values, respectively. By coupling these results to a box model, we show that increased marine productivity and successive enhanced microbial sulfate reduction is the most likely scenario to explain these temporal trends. The new data demonstrate that worldwide expansion of euxinic and anoxic zones are symptoms of increased biological carbon recycling in the marine realm initiated by global warming. The spatial distribution of sulfidic water column conditions in shallow seafloor environments is dictated by the severity and geographic patterns of nutrient fluxes and serves as an adequate model to explain the scale of the marine biodiversity crisis. Our results provide evidence that the major biodiversity crises in Earth’s history do not necessarily implicate an ocean stripped of (most) life but rather the demise of certain eukaryotic organisms, leading to a decline in species richness.