富营养化湖泊藻源磷降解机理及其环境效应

The important type of internal phosphorus cycling in eutrophic lake is regeneration of algae-derived phosphorus and its fate and transport back into the water column. However, main controlling factors in decomposition process of algae-derived phosphorus, driving effects on orthophosphate monoesters, orthophosphate diester, polyphosphate and pyrophosphate during decomposition process have been little studied. The purpose of this proposal is to study decomposition, fate and transport of different phosphorus species during decomposition process and their environmental effects in eutrophic lake. The study will employ innovative methods, including 31P nuclear magnetic resonance spectrum analysis and diffusive gradients in thin-films, to examine decomposed product of organic phosphorus, and polyphosphate by microcystin in lab. The investigator will explore the microcystin sources of orthophosphate monoesters, orthophosphate diester, polyphosphate, pyrophosphate and orthophosphorus using decomposition studies under different environmental conditions such as hydrodynamic conditions, dissolved oxygen, microorganism, and reveal the pathway and mechanisms of decomposition, the relationship between algae-derived phosphorus and organic matter. We will study the flux of algae-derived bioavailable phosphorus release from decomposition process and estimate its contribution to the algae boom. Under the main controlling factors on the decomposition of algae, using simulation experiment by modified re-suspension device in lab and in situ observation in field, The fate and transport of orthophosphate monoesters, orthophosphate diester, polyphosphate, pyrophosphate and orthophosphorus in the different environmental media of lake, the release behavior of bioavailable phosphorus which driven by decomposition of algae-derived phosphorus will also to be studied. The sorption behavior of bioavailable phosphorus with and without the algae-derived dissolved organic matter on surface sediment is going to be investigated. A modified bioavailable phosphorus release model which driven by algae decomposition in an eutrophic lake environment will be established. Results form this project will fill a gap in our knowledge of internal phosphorus cycling in eutrophic lake environments, and provide insight into the environmental impact of algae-derived phosphorus. Information generated from this research will also provide a scientific basis for sustainable management of lake eutrophication.

蓝藻降解磷进入水体是湖泊内源磷循环的重要环节，目前藻类降解磷的研究多集中在无机磷方面，对藻源磷有机磷和聚磷降解机理、藻源磷降解驱动下单酯磷、二酯磷、聚磷和焦磷等磷形态在湖泊水环境介质间迁移转化规律认识上的不足限制了湖泊内源磷循环理论的进一步发展。据此提出以微囊藻源磷为对象，31P核磁共振、薄膜梯度扩散等为手段，构建水动力、溶解氧、微生物等因素影响下藻源磷降解实验体系，探究降解过程中藻源有机磷和聚磷的降解机理，定量估算藻源生物可利用磷的释放通量；利用改进的再悬浮装置室内模拟以及对蓝藻聚集区的定点观测，探索藻源磷降解主要控制因素影响下，藻源磷降解驱动的不同形态磷在水-悬浮物-沉积物间的迁移转化规律以及生物可利用磷的变化特征，揭示藻源溶解有机质对生物可利用磷迁移转化的作用机制；构建并修正藻源磷降解驱动下的生物可利用磷释放模型；揭示藻源磷降解的环境效应。研究结果将为湖泊内源磷循环理论发展提供参考。

蓝藻降解磷进入水体是湖泊内源磷循环的重要环节，目前藻源磷降解的主要控制因素以及对藻源单酯磷、二酯磷、聚磷和焦磷等磷形态在湖泊水环境介质间迁移转化规律认识上的不足限制了湖泊内源磷循环理论的进一步发展，项目针对蓝藻消亡过程中藻源磷的释放及变化特征开展了系统研究，利用液体和固体磷核磁共振相结合的方法，系统阐述了典型富营养湖泊各形态磷在水-悬浮物-沉积物间的迁移转化规律，研究了不同环境因子影响下蓝藻降解过程中不同形态磷的释放特征，揭示了不同形态磷在不同介质中的迁移转化规律，研究结果为丰富湖泊内源磷循环理论发展提供了参考，也为水体磷污染监测与控制提供了技术支持。