New Insights Key Factor of Cambrian 'Great Burst of Life' Discovered
TapTechNews July 13th news, the early Cambrian period (539–514 Ma) witnessed a rapid increase in the variety, morphological differences, and ecological complexity of early animals, known as the Cambrian Great Burst of Life.
The traditional view holds that the main controlling factor of this event is the oxidation of the ocean, but experiments show that the early animals do not have a high demand for oxygen. Now, Associate Researcher Wei Wei of the University of Science and Technology of China, Doctoral Student Dong Linhui, and Professor Huang Fang have discovered the key factor of the Cambrian Great Burst of Life.
The research team proposed that the oxidation of seawater acts as a water purifier, removing sulfide and barium ions that are toxic to early animals, thereby promoting the Cambrian Great Burst of Life. The relevant results have been published in the National Science Review (TapTechNews attaches DOI: 10.1093/nsr/nwae237).
In the Neoproterozoic, the oxidation of the ocean would cause the sulfur species in it to change from sulfide to sulfate, and further affect the biogeochemical cycle of barium (Ba). The Lower Cambrian black shale widely distributed in the Yangtze Plate in South China preserves unique polymetallic ore layers, including nickel-molybdenum ore, vanadium ore and barite ore, etc., and its sedimentary age (521 Ma) is older than the strata that preserve the Chengjiang and Qingjiang biota (representing the heyday of the Cambrian Great Burst of Life). Therefore, this ore layer should record the significant changes in the ocean chemical composition during the Cambrian Great Burst of Life.
Through the barium isotope data analysis of sedimentary rocks deposited during the heyday of the Cambrian Great Burst of Life in Hunan and Guizhou, Team Wei Wei found that during the Ediacaran-Cambrian transition period about 560-520 million years ago, the gradual oxidation of the ocean increased the sulfate concentration, so that the previously accumulated dissolved barium ions were removed in large quantities in the form of barite.
The result is that a high concentration of barium in the water body will inhibit the survival rate of aquatic animals. Therefore, the removal of sulfide and barium ions that are toxic to animals improves the habitability of the ocean, thereby promoting the Cambrian Great Burst of Life. This discovery provides new insights into the feedback mechanism between the early Cambrian ocean oxidation and the Great Burst of Life.
