基于生物扰动的沉积物混合与寒武纪底质革命

The sediment bioturbation of burrowing animals highly impact the nature of sediment and the geochemical cycle between sediment and seawater. Cambrian bioturbated sediment mixing and the evolution of substrate are the one of most profound environmental changes caused by organisms in life history of the world. But there are some divergences about the timing and nature of Cambrian sediment mixing. It is still unclear that the development of geochemical cycles caused by burrowing animals and the detailed changing path and relative chronology of substrate evolutions. This project takes the bioturbated sediment mixing as the breakthrough point to expound the impact of sediment geochemical and nutrient cycles and colonization of the infaunal ecopace for the bioturbators as ecosystem engineers; to uncover the coexist and evolution of matground and mixground in profile and the controlling factors. It can provide evidences for the study of evolution of Cambrian sedimentary substrates and its synergy with geobiological outcomes.

倔穴动物对沉积物的扰动改造强烈地影响着沉积物的性质及沉积物与海水的地球化学循环。寒武纪生物扰动作用导致的沉积物混合和底质变革是地球生命史上有机体引起的最深刻的环境变化之一。但是关于寒武纪沉积物混合的时间和性质仍有一些分歧，造迹者混合沉积物引起的地球化学循环过程及底质变革的具体路径和时间仍不清楚。本项目以后生动物扰动引起的沉积物混合为切入点，阐明扰动生物作为生态系统工程建造者对沉积物地球化学和营养物循环过程的影响和对内栖生态空间的殖居机制，揭示席底与混合底在剖面上的共存与演变特征及控制因素，为寒武纪沉积底质演化及其与地球生物学之间的协同关系研究提供依据。

本项目以后生动物扰动引起的沉积物混合为切入点，阐明了扰动生物作为生态系统工程建造者对沉积物地球化学和营养物循环过程的影响和对内栖生态空间的殖居机制，揭示了席底与混合底在剖面上的共存与演变特征及控制因素。研究表明，寒武纪大爆发后，海底生态系统建造者已经占据了更深的阶层和的大量空缺的生态位，觅食方式变得更加多样，生态系统工程的复杂性逐渐增加。随着底栖生态系统的逐渐完善，底栖生态系统工程建造者诱导了寒武纪底质革命，使混合底逐渐发育，微生物席底受到抑制。从整体上来看，寒武纪以两种沉积底质的耦合发育为特点。底栖建造者在生态系统工程过程中不仅能够影响沉积底质的物理性质，而且能够显著影响大气-海洋-沉积物地球化学循环，为底栖群落的演化提供了必要条件。