Mid-Cretaceous Hothouse Climate and the Expansion of Early Angiosperms
Mid-Cretaceous Hothouse Climate and the Expansion of Early Angiosperms
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白垩纪中期温室气候与早期被子植物的扩张
DOI：
10.1111/1755-6724.13692
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Shusheng HU
中科院分区：
文献类型：
--
作者：
Mingzhen ZHANG;Shuang DAI;Baoxia DU;Liming JI;Shusheng HU
早期被子植物从一个小类群到一个优势类群的显著转变是白垩纪陆地生态系统的特征。这一转变是由环境变化引发和推动的。白垩纪中期以影响全球环境的重大地质事件为特征。δ18O、古温度计TEX86和其他来自海洋沉积物的气候指数表明，尽管偶尔发生短暂的降温事件，但白垩纪中期气温迅速上升。同时，东亚陆相沉积从含煤到页岩，再到红层和蒸发岩。植物组合和其他古气候指标表明，白垩纪中期陆地环境迅速干旱化。此外，在白垩纪中期，由于大量的木炭证据，野火经常蔓延到地球各地。因此，我们推测，白垩纪中期的季节性干燥和炎热条件创造了一个火热的温室世界。早期被子植物的丰富度和多样性增加，从几个水生物种演变为陆生草本，然后演变为今天多样化的植物区系。被子植物在叶脉密度和叶面积方面表现出快速的生理进化，促进了光合作用和水分吸收。这些生态生理变化使早期被子植物较好地适应了白垩纪中期炎热干燥的环境。此外，这些生理变化促进了白垩纪中期的火-被子植物旋回，这可能进一步刺激了被子植物的早期进化。
The remarkable transition of early angiosperms from a small to a dominant group characterized the terrestrial ecosystem of the Cretaceous. This transition was instigated and promoted by environmental changes. Mid‐Cretaceous is characterized by major geological events that affected the global environment.δ18O, palaeothermometer TEX86, and other climatic indices from marine sediments suggest rapid temperature increase during mid‐Cretaceous despite occasional short cooling events. Simultaneously, terrestrial deposits in East Asia changed from coal‐bearing to shale, then to red beds and evaporites. Plant assemblages and other paleoclimate indicators point to rapid aridification for mid‐Cretaceous terrestrial environments. In addition, the wildfires were frequently spread all over the earth by the numerous charcoal evidence during the Mid‐Cretaceous. Thus, we speculate that the seasonally dry and hot conditions of mid‐Cretaceous created a fiery hothouse world. Early angiosperms increased in abundance and diversity and evolved from a few aquatic species to terrestrial herbaceous and then to the diversified flora of today. Angiosperms showed rapid physiological evolution in vein density and leaf area that improved photosynthesis and water absorption. These ecophysiological changes made early angiosperms well adapted to the hot and dry environment in mid‐Cretaceous. Moreover, these physiological changes facilitated the fire–angiosperm cycles in mid‐Cretaceous that likely further stimulated the early angiosperm evolution.