蓝藻群体颗粒驱动元素地球化学循环研究进展

Biogeochemical cycling processes associated with cyanobacterial aggregates

在天然淡水和半咸水水体中,水华蓝藻常以群体颗粒的形态存在。在蓝藻群体颗粒中聚集着大量异养细菌,和蓝藻共同构成了具有独特生态功能的基本单元。与蓝藻单体细胞相比,蓝藻群体颗粒呈现出许多独有的特性,如内部丰富的有机质、急剧的氧化还原梯度、密切的种间互作关系等等。这些特质使得蓝藻群体颗粒在水体中成为元素地球化学循环的反应热点。同时,在蓝藻群体颗粒中也存在着远比单细胞藻类-浮游细菌之间更为密切的种间互作。本综述围绕蓝藻群体颗粒的这些特点,结合当前的研究进展,重点阐述蓝藻群体颗粒中的生物、生理、化学过程,讨论其驱动宏观生态现象的微观机制。未来蓝藻群体颗粒组学研究和多组学微生态数据库的构建或成为探索蓝藻群体颗粒中生命过程及揭示蓝藻水华暴发机制的突破口之一。

In natural freshwater and low-salinity waters,bloom-forming cyanobacteria often live in the form of cyanobacterial aggregates.Many heterotrophic bacteria colonize in the cyanobacterial aggregates,subsequently they constitute the fundamental unit with unique ecological functions.Compared with single-celled cyanobacteria,cyanobacterial aggregates exhibit many unique characteristics,e.g.,rich organic matter,steep redox gradient,and complex inter-specific interactions.These properties enable cyanobacterial aggregates to become the hotspot for elemental biogeochemical cycling in aquatic ecosystems.Meanwhile,the inter-specific interactions within cyanobacterial aggregates are far more intense compared to those between single-celled algae and free-living bacteria.This review introduces current research progress on these aspects,with a focus on the biological,physiological and chemical processes within cyanobacterial aggregates,and discusses the micro-mechanisms of the macro-phenomena.In the future,the omic research of cyanobacterial aggregates and the construction of multi-omic microecological databases may become the key for exploring life processes within cyanobacterial aggregates and for revealing the mechanisms of cyanobacterial bloom outbreak.