Morphological record of oxygenic photosynthesis in conical stromatolites
Morphological record of oxygenic photosynthesis in conical stromatolites
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DOI：
10.1073/pnas.0900885106
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发表时间：
2009-07-07
影响因子：
11.1
通讯作者：
Petroff, Alexander P.
中科院分区：
文献类型：
--
作者：
Bosak, Tanja;Liang, Biqing;Petroff, Alexander P.
圆锥形的叠层石被认为是早在35亿年前水生环境中光合和趋光微生物存在的有力指标。然而，趋光性本身并不能解释在许多中元古代、古元古代和一些太古代的锥形叠层石的顶部普遍存在的断裂、卷曲和扭曲纹层。在这里，我们表明，蓝藻生产的氧气在现代圆锥形聚集体的尖端创建扭曲的薄层和亚毫米到毫米级的纠缠气泡。类似大小的化石气泡和扭曲的纹层可能只存在于一些27亿年或更年轻的圆锥形叠层石的顶部区域。这不仅意味着蓝藻建造了元古宙的锥形叠层石，而且化石泡可能限制了光合作用演化的时间。
Conical stromatolites are thought to be robust indicators of the presence of photosynthetic and phototactic microbes in aquatic environments as early as 3.5 billion years ago. However, phototaxis alone cannot explain the ubiquity of disrupted, curled, and contorted laminae in the crests of many Mesoproterozoic, Paleoproterozoic, and some Archean conical stromatolites. Here, we demonstrate that cyanobacterial production of oxygen in the tips of modern conical aggregates creates contorted laminae and submillimeter-to-millimeter-scale enmeshed bubbles. Similarly sized fossil bubbles and contorted laminae may be present only in the crestal zones of some conical stromatolites 2.7 billion years old or younger. This implies not only that cyanobacteria built Proterozoic conical stromatolites but also that fossil bubbles may constrain the timing of the evolution of oxygenic photosynthesis.