Detailed researches on the stable carbon isotopes at the Loufangwan Section, Huaying, Sichuan Province show the stable carbon isotopes has the similarities with many other Permian-Triassic records around the world. A larger mean value of Δ_B in earliest Triassic than that in latest Permian indicates increasing concentration of phosphate and bloom of primary producers in the ocean. Large volcanic eruption and enhanced weathering that began in the end of Permian were possible triggers for a slow decrease in δ¹³C_carb. Synchronously, quick decreases in δ¹³C_carb and δ¹³C_org in the earliest Triassic, indicating a global carbon cycle change, might be due to the main episode of the mass extinction and upwelling of anoxic deep-water masses during sea level rise. Therefore, the carbon isotopes profile around the Permian-Triassic boundary may reflect combined results of volcanic activity, sea level change, mass extinction of marine and land biomass decrease and anoxic water upwelling.

Morphological and ecological diversity of organisms increased during the global Great Biodiversification Event from the late Early Ordovician. Those changes were accompanied with a marked declines in microbial reefs in the subtidal settings. The reefs were built by benthic microbes, Calathium, and lithistid sponges in the middle Early Ordovician Honghuayuan Formation of Jianxin, Anhui Province. The reefs exhibit three main rock types: 1) massive skeletal grainstones， 2) lithistid sponge Calathium-microbial bindstones, and 3) microbial boundstones. Girvanella, one of representative calcimicrobes, is classified into four categories in the reefs: 1) dispersed, 2) encrusting, 3) forming into intraclasts, and 4) infilling within sponges. These types of Girvanella play a significant frame-building role in the Calathium/ lithistid sponge- microbial reefs of the Honghuayuan Formation. Such kind of microbial reefs commonly occur in the Yangtze Platform and elsewhere in the world just prior to the first acme ofthe Ordovician biodiversification. Metazoan competitions with microbes might be closely related to marked declines in microbial sediments decline after the deposition of the microbial reefs of the Honghuayuan Formation.