聚球藻硅质化作用初探

Preliminary thoughts on Silicon accumulation in Synechococcus

硅元素是全球生地化循环的重要组成成分之一,对海洋生态系统中以浮游植物主导的初级生产力和硅碳循环具有重要的意义。普遍认为硅藻主导着全球海洋的硅循环,成为海洋硅循环和碳循环交互作用的重要桥梁。海洋单细胞聚球藻对海洋食物网和能量流具有关键启动和支撑作用,是全球碳循环中固碳过程的主要贡献者,近年又被发现其具有重要的硅质化作用,为我们提供了一个在海洋中(特别是寡营养海域),除硅藻之外,连接硅碳循环交互作用的新视角,对硅藻在全球海洋硅碳循环的绝对地位具有重要的挑战意义。面对聚球藻在大洋中如此巨大的生物量,甚至高于硅藻,有必要弄清楚其碳沉降机制以及准确的模拟其硅循环,然而关于其在海洋硅循环的研究极少,硅质化作用的吸收和储存机理以及环境调节机制也不清楚;另外,其对世界海洋硅碳循环的调节作用也未见报道。为此,通过前人对海洋单细胞聚球藻硅质化作用研究的基础上进行有针对性的探讨,可望对海洋单细胞聚球藻硅质化作用及其对硅碳循环的调控机制有一个基本的认识,为深入研究聚球藻在全球海洋硅循环中的作用提供基础。

Silicon （Si）, as one of the important components of the global biogeochemical cycles, is of great significance to the primary productivity dominated by phytoplankton and the silicon and carbon cycles in marine ecosystem. It is well known that diatoms dominate the silicon cycle of the global ocean, and become an important bridge for the interaction between the silicon cycle and carbon cycle. Individual cells of Synechococcus play a key role in starting and supporting marine food web and energy flow, thus they become the main contributors in global carbon cycle, recently, they were also found to have important function in Si accumulation, which provides us a new perspective in silicon and carbon cycles in open ocean in addition to diatoms, however, the discovery of Si accumulation by marine Synechococcus shows a large challenge to the absolute position of diatoms in the global silicon and carbon cycles. For such a huge biomass of Synechococcus in the ocean, even higher than that of diatoms, it is necessary to understand what is the mechanism of carbon sinking and to accurately simulate its silicon cycle, nevertheless, the researches on Si accumulation by marine Synechococcus are very rare, the mechanism of Si absorption and storage as well as the role of regulation mechanism are not clear. In addition, its regulatory effect on the silicon carbon cycle has not been reported. Therefore, based on the previous studies in Si accumulation of individual cells of Synechococcus, we hope that there will be a basic understanding of Si accumulation by marine Synechococcus and their regulatory mechanism of silicon and carbon cycles in marine ecosystem.