蓝细菌作为古老的自养生物群, 在地球生命演化、环境演化和微生物岩形成中发挥着重要作用。 Girvanella是蓝细菌常见的化石形态属之一, 为切实反映其在中国寒武纪的保存方式、多样性与时空分布等特征, 本文汇编与分析了Girvanella化石数据, 结果表明: (1)中国寒武纪Girvanella化石以钙化的保存为主, 多见于微生物岩中, 磷酸盐化和铁矿化次之, 分别出现在磷块岩和铁质叠层石中; (2)共计4个Girvanella化石种。寒武纪纽芬兰世–第二世, 种数量不变, 地理分布有所增加。至苗岭世, 多样性和地理分布均达到峰值。芙蓉世, 种数量和地理分布均有所萎缩。深入探讨发现, Girvanella归属于颤菌科, 海水碳酸盐饱和度、Ca²⁺浓度和pH值, 以及大气 CO₂浓度是影响Girvanella化石形成的因素。钙化Girvanella化石是丝状蓝细菌利用二氧化碳浓缩机制诱导胶鞘钙化的产物; 磷酸盐化保存的化石多为次生磷酸盐化的结果; 铁矿化保存的化石可能由丝状蓝细菌通过细胞本身或胞外聚合物吸附和黏结水体环境中的絮状沉积物所致。Girvanella通过自身和微生物席的复杂钙化作用, 以及微生物席的黏结与捕获作用参与微生物岩的形成, 在后生动物礁建造和结构稳定性加固方面发挥着关键作用。 同时, 证实了Girvanella化石记录对古代海洋和大气成分的长期变化具有指示意义。

Cyanobacteria, as ancient autotrophic groups, have played vital roles in the evolution of life, environmental changes, and the formation of microbialites on Earth. Girvanella is one of the common form genera of cyanobacteria. In this paper, we compiled and analyzed relevant data on Girvanella from the Cambrian of China to better understand its preservation modes, diversity, and spatio-temporal distribution patterns. The results indicate that: (1) Cambrian Girvanella fossils from China are predominantly preserved through calcification, mostly in microbialites, with secondary preservation through phosphatization and iron mineralization in phosphorites and ferruginous stromatolites, respectively. (2) Four species of Girvanella have been identified; The species diversity of Girvanella remained stable, while its geographic distribution expanded from the Terreneuvian to Epoch 2, peaking during the Miaolingian Epoch; However, both species diversity and geographic distribution declined during the Furongian Epoch. Further investigation reveals that Girvanella belongs to the Oscillatoriaceae, and that factors such as seawater carbonate saturation, Ca²⁺ concentration, pH values, and atmospheric CO₂ concentration influence its fossilization. Calcified fossils of Girvanella are likely resulted from filamentous cyanobacteria employing carbon-concentrating mechanisms that induced sheath calcification. Phosphatized fossils of Girvanella reflect secondary phosphatization, while iron–mineralized specimens may have formed through absorbing and binding flocculated sediments by filamentous cyanobacteria, either via the cells themselves or extracellular polymeric substances. Girvanella contributes to the formation of microbialites through the complicated calcification process of both themselves and microbial mats, as well as trapping and binding microbial mats that are dominated by these organisms. Additionally, also plays a significant role in constructing and reinforcing the structural stability of metazoan reefs. The fossil record of Girvanella also serves as an important indicator of long-term changes in the composition of the ancient oceans and the atmosphere.

国家重大科技专项(2017ZX05008-005-010)和国家自然科学基金项目(41872115)联合资助