微生物与沉积岩的协同演化【纪念专刊】
- 收稿日期:
2023-08-13
- 网络出版日期:
2023-10-30
摘要: 生物圈是地球区别于其他星球的一大关键，微生物因时空分布广、代谢功能多样、繁殖快、丰度高而对地球的宜居性产生重要影响，其中的一大途径是形成各类沉积岩。地质时期的条带状硅铁建造、灰岩、白云岩、磷块岩、硅质岩等沉积岩都与微生物作用分不开，甚至一部分泥岩的形成也可能与微生物作用有关。正因为微生物参与了许多沉积岩的形成，导致地质时期的微生物与沉积岩具有协同演化的关系。太古宙虽然以火成岩为主，少量的沉积岩也以物理作用为主，但铁代谢微生物广泛参与了条带状硅铁建造的形成。元古宙的沉积岩发生了革命性变化，其丰度远比火成岩多，而且微生物作用明显加强。元古宙出现了大量丰富多彩的钙质微生物岩和微生物成因沉积构造，白云岩也出现峰值。在元古宙末期，泥岩丰度的增加与陆地低等生物繁盛而导致粘土矿物工厂的生产机制升级有关。在元古宙与显生宙的过渡时期，出现了从硅质、磷质到钙质的转换，这与原核微生物向真核微生物再向多细胞动物的演化以及海洋环境的pH和Eh等条件变化有关。到了显生宙，多细胞动物大发展，而微生物群落受到压制，白云岩丰度开始降低。在真核微生物方面，古生代绿藻类的优势被中-新生代的红枝藻系所代替，使得碳酸钙沉积从浅水向深水扩展。特别是，在显生宙一些重大突变期，碳酸盐工厂出现从骨架灰岩到钙质微生物岩的5次大转换，并且出现一些错时相和微生物成因沉积构造，这些都与宏体生物出现危机后微生物生态系的短暂发展有关。高等植物登陆后，泥岩丰度在志留纪以后猛增，这与高等植物登陆导致的粘土矿物工厂又一次变革以及植物-微生物相互作用导致有机质絮凝作用的加强有关。
Coevolution of microorganisms and sedimentary rocks
- Received Date:
2023-08-13
- Available Online:
2023-10-30
Abstract: Earth is different from other planets due to the presence of the biosphere. Microorganisms in the biosphere have played, and are playing, important roles in shaping Earth habitability due to their wide spatiotemporal occurrence, diverse metabolism functions, rapid multiplication, and great abundance. One of the critical processes is the microbial involvement of sedimentation, resulting in the biogenic formation of sedimentary rocks including banded iron formation, limestone, dolomite, phosphorite, siliceous rock,as well as some mudstones, which in turn caused the coevolution of microbes and sedimentary rocks in Earth history. Archean is dominated by the magmatic rocks, and the sedimentary rocks are mainly related to the physical processes. The banded iron formation is however related to the contribution of photoferrotrophic bacteria. Great changes occurred in Proterozoic when sedimentary rocks overthrow magmatic rocks in abundance and the diverse biogenic rocks (calcimicrobialites, dolomites) greatly increased in abundance. Microbially-induced sedimentary structures are also diverse and in great abundance. Mudstone starts to increase in abundance at the end of Proterozoic due to the development of microorganism on land which brought into coming of a new clay factory. The transition interval across Neoproterozoic and Cambrian boundary witnessed the shift from siliceous to phosphatic and finally to calcareous rocks, coincident with the evolution from prokaryotes to eukaryotic microorganisms and finally to metazoans, showing their causal relationship. In phanerozoic, dolomite shows a sharp decrease in abundance due to the metazoan expansion and its suppression on microorganisms. Green algae dominance in Paleozoic shifted to the dominance of red algae in Mesozoic and Cenozoic, favoring the expansion of calcium carbonate from shallow water to deep water. In particular, carbonate factory showed the shift from skeleton limestones to calcimicrobialites for at least 5 times, in association with the occurrence of anachronistic facies as well as MISS; these are due to the transient expansion of microbial communities immediately after the biotic crisis. Mudstones increased in abundance immediately after the development of terrestrial ecosystems due to the innovation of clay factory on land and the enhanced precipitation of clay minerals caused by the organic-induced flocculation.
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