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二叠纪末生物大绝灭后出现的微生物群落是一个异常极端环境下的产物,不同的地区微生物的类型也不同.研究了重庆附近著名的二叠系-三叠系界线地层连续出露地区——老龙洞的界线剖面,在发生生物大绝灭之后的地层内,一段以管状蓝细菌化石为主的微生物群落的地层.根据薄片观察,管状蓝细菌化石的长度一般在1mm以下,粗端直径最大0.08mm,几乎所有的管状化石都是向一端逐渐变细的,管状体比较柔软,管体的壁由隐晶到微晶的方解石组成,横切面为圆形,几乎所有的管状化石的内部都是空的,并被泥晶方解石或细亮晶方解石充填.总体上分布无规律,但在若干视野中见到它们有呈放射状或束状排列的趋向.通过综合对比研究认为,该化石与蓝细菌门的胶须藻科(Rivulariaceae)的胶须藻很相似,但是该化石是胶鞘钙化的种类,而胶须藻科的Rivularia属种是不钙化的.考虑到该化石保存的其他可供进一步分类的特征非常有限,因此将其归入胶须藻Rivularia,描述为Rivularia sp.[胶须藻(未定种)].因为蓝细菌是一种光合自养生物,可以适应贫氧环境,大绝灭后首先出现蓝细菌的群落可能说明环境是贫氧的.由于光合作用需要浅水环境,蓝细菌的存在也说明当时的水体是比较浅的.
The microbial community that emerged after the Permian extinction was a product of abnormal extreme environment and different types of microorganisms in different regions.Research was made on the continuous Permian-Triassic boundary stratum area near Chongqing - the section of Laolongdong boundary, a layer of microflora dominated by tubular cyanobacteria in the strata after the great extinction of the organism.According to the observation of thin slices, the length of the tubular cyanobacteria fossils is generally below 1mm, The diameter of the largest 0.08mm, almost all of the tubular fossils are tapered to one end, the tubular body is relatively soft, the wall of the tube from cryptocrystalline to microcrystalline calcite composition, cross-section is circular, almost all tubular fossils The interior is empty and filled with clay calcite or fine-grained calcite, which is generally irregular in distribution but tends to appear radially or bundle-like in a few fields of view.Through a comprehensive comparative study, the fossil Similar to the cyanobacteria belonging to the genus Rivulariaceae of the genus Cyanobacteria, this fossil is a type of plasticated callus, while the Rivularia genus of the genus Algae is non-calcified. Considering that Other features preserved by the stone for further classification are very limited and are therefore classified as Rivularia, described as Rivularia sp. [Cyathula (undetermined species)] Because Cyanobacteria are photosynthetic autotrophs that can Adapting to an oxygen-deficient environment, the first appearance of cyanobacterial communities after a major extinction may indicate that the environment is oxygen-depleted, and the presence of cyanobacteria also suggests that the water bodies at that time were relatively shallow due to the shallow water environment required for photosynthesis.