有机磷对水库沉积物拟多甲藻孢囊萌发与竞争增殖的影响及机制

Freshwater dinoflagellate bloom has become one of water environmental issues in China.The dinoflagellate cysts formed under adverse condition can germinate and recruit when encountering suitable environment, consequently resulting the bloom initiation.The extracellular phosphatase secreted by dinoflagellate has been found as one of the key factors effectively promoting the utilizetion of organic phosphorus for competitive advantages.However, few studies have focused on the spcific types of organic phosphorus for dinoflagellate usage and the biological mechanisms of phosphate acquisition at molecular level.This study aims to identify and characterize the correlation of micro algae community succession and temporal dynamics of nutrition in the sediment-water interface,with the case study in the dinoflagellate bloom Reservoirs.We analyze the sediment organic phosphorus forms by the 31P NMR analysis and identify the specific organic phosphorus by the BIOLOG multi-application of phosphorus source plate culture technique. We study the sediment dinoflagellate cysts germinate proliferation with the overlying water microalgae community succession by using microscopic observation, enzyem labeled fluorescence (ELF) and genomic sequencing.We will also undertake both laboratory cultivatoin , field observation and in situ mesocosm experiment to further verify the organic phosphorus utilization during Peridiniopsis cyst germination and competition proliferation in natural environment, then explore its molecular biological mechanism.By identifying the biomarkers in sediment for phosphorus nutritiong,this study can offer a biological evidence for the biocompatibility theory of algae evolution and community succession during bloom itiation process.The expected results can contribute to the establishment of early warning and efficient control of dinoflagellate blooms,which showing important theoretical and practical significance.

淡水甲藻水华已成为人们关注的水环境问题之一，不利环境下形成的甲藻孢囊可以在一定条件下萌发增殖，是促成甲藻水华暴发的重要原因之一。甲藻细胞分泌的碱性磷酸酶可以有效提高其对有机磷的利用率，从而形成种间竞争的优势，但甲藻对有机磷的利用策略及其分子生物学机理仍未解析清楚。本研究以国内爆发甲藻水华的水库为研究对象，应用31P核磁共振技术，分析沉积物有机磷形态；应用BIOLOG平板培养技术，识别特异性有机磷；综合显微观察、酶标记荧光、基因序列分析等技术，研究沉积物甲藻孢囊萌发增殖与上覆水体中微藻群落的演替。通过野外观测结合实验室培养，并在原位环境中展开围隔试验加以验证，揭示拟多甲藻孢囊萌发与增殖过程中对有机磷的利用策略，探索其分子生物学机理，构建指示沉积物磷营养状态的分子标记物，丰富藻类进化和群落演替过程中生物适应性理论并提供分子生物学证据。本研究对甲藻水华的预测和防控具有重要的理论意义和现实意义。

项目组从2016年-2019年，对福建九龙江沉积物藻类16S rDNA和18S rDNA测序，摸清了水库沉积物—水界面的微藻群落结构，包括硅藻、绿藻、隐藻、甲藻和蓝藻；通过显微观察结合PCR技术，揭示水库沉积物样品中聚磷菌以变形菌门、放线菌门和酸杆菌门为主，Fe /Al-P 与聚磷菌多样性指数的相关性显著。九龙江库区春季的甲藻丰度与活性磷呈负相关。.将甲藻门楯形多甲藻（Peridinium umbonatum var.inaequale）和蓝藻门铜绿微囊藻（Microcystis aeruginosa）接种至51种磷源的BIOLOG微孔培养板中，在单培养和混合培养条件下，两种藻都可以利用核苷酸、糖类衍生物、磷酸甘油和膦酸盐，探明了不同有机磷对多甲藻孢囊萌发与增殖影响。研究楯形多甲藻和铜绿微囊藻在5’-单磷酸腺苷等有机磷培养条件下碱性磷酸酶（AP）的分布，识别单细胞水平胞外磷酸酶的分布和动力学特征。结果表明，碱性磷酸酶活性是磷缺乏的指标，但不是有机磷存在的指标，不同种类的藻利用不同有机磷的潜在机制是不同的。阐明了碱性磷酸酶活性与甲藻萌发增殖的之间的对应关系，揭示了多甲藻利用核苷单磷酸、磷酸甘油等有机磷的分子生物学机理。.探究了藻竞争利用有机磷增殖对浮游植物群落结构影响,楯形多甲藻不等变种能够较好的利用核苷酸，当调控藻起始生物量多甲藻占比30%以上时,多甲藻的竞争优势明显，环境条件一定时,磷源形态和藻类起始生物量结构共同影响浮游植物群落结构演替。探讨了有机磷对以九龙江北溪西陂水库原位沉积物-水界面浮游植物群落结构演替的影响，再次证明了磷的形态对浮游植物群落结构具有重要的影响。