Del Rey Álvaro, Rasmussen Christian Mac Ørum, Calner Mikael, Wu Rongchang, Asael Dan, Dahl Tais W
GLOBE Institute, University of Copenhagen, Øster Voldgade 5-7, DK-1350 Copenhagen K, Denmark.
Department of Geology, Lund University, Sölvegatan 12, SE-223 62 Lund, Sweden.
Commun Earth Environ. 2022;3(1):220. doi: 10.1038/s43247-022-00548-w. Epub 2022 Sep 22.
The Great Ordovician Biodiversification Event (GOBE) represents the greatest increase in marine animal biodiversity ever recorded. What caused this transformation is heavily debated. One hypothesis states that rising atmospheric oxygen levels drove the biodiversification based on the premise that animals require oxygen for their metabolism. Here, we present uranium isotope data from a Middle Ordovician marine carbonate succession that shows the steepest rise in generic richness occurred with global marine redox stability. Ocean oxygenation ensued later and could not have driven the biodiversification. Stable marine anoxic zones prevailed during the maximum increase in biodiversity (Dapingian-early Darriwilian) when the life expectancy of evolving genera greatly increased. Subsequently, unstable ocean redox conditions occurred together with a marine carbon cycle disturbance and a decrease in relative diversification rates. Therefore, we propose that oceanic redox stability was a factor in facilitating the establishment of more resilient ecosystems allowing marine animal life to radiate.
奥陶纪生物大辐射事件（GOBE）代表了有记录以来海洋动物生物多样性的最大增长。是什么导致了这种转变，目前仍存在激烈争论。一种假说认为，大气氧含量上升推动了生物多样性的增加，其依据是动物的新陈代谢需要氧气。在此，我们展示了来自中奥陶世海相碳酸盐序列的铀同位素数据，这些数据表明，在全球海洋氧化还原稳定性时期，属级丰富度出现了最急剧的上升。随后才出现海洋氧合作用，因此它不可能是生物多样性增加的驱动因素。在生物多样性最大增加期（达平阶—大坪阶早期），稳定的海洋缺氧带普遍存在，此时演化属的寿命大幅增加。随后，不稳定的海洋氧化还原条件与海洋碳循环扰动以及相对多样化速率的下降同时出现。因此，我们认为海洋氧化还原稳定性是促进建立更具复原力的生态系统、从而使海洋动物得以辐射演化的一个因素。
