二氧化碳浓度升高对浮游藻类病毒增殖及光修复能力的影响

Algal virus have some very important ecolgical functions,such as the regulation of the primary productivity and population structure of phycoplankton, as well as the influence on the biogeochemical cycle of the earth. The propagation and photo-reactivation ability of the algal virus are the foundation of those functions，and the increasing atmospheric CO2 concentration may influence the propagation and photo-reactivation ability of algal virus via the physiological variation of those host algal cells. Thus, the project to study "the effect of CO2 enrichment on the propagation and photo-reactivation ability of algal virus mediated by host cells" is of theoretical importance to discover the functional variation of algal virus in the condition of increasing atmospheric CO2 concentration. .The project plans to compare the changes of "virus-host algae" systems isolated from freshwater and marine environment.Via experiment in short,middle and long period, the adsorption ratio, lyric cycle, burst size, photo-reactivation ratio and photo-reactivation conditions will be studied on the condition of increased CO2 concentration or the condition of increased temperature or both. Then the experiment will be moved to enclosures in a lake to study the effect of CO2 enrichment on the propagation and photo-reactivation ability of cyanophage PP in field conditions. Finally a model will be established to describe the influence of CO2 enrichment on the propagation rate and photo-reactivation ratio of algal virus, by which the functional variation of the algal virus could be inferred.

藻类病毒具有调节浮游藻类初级生产力和种群结构，影响生物地球化学循环等重要功能。藻类病毒的增殖与光修复是维持病毒生态功能的基础，而大气二氧化碳浓度不断升高很可能通过影响宿主藻类的生理状态而影响藻类病毒的增殖与光修复过程。因此研究"二氧化碳浓度升高对浮游藻类病毒增殖及光修复能力的影响"对揭示二氧化碳浓度升高条件下浮游病毒生态功能的变化具有重要的理论意义。.本项目拟对比研究淡水与海水的"病毒-宿主藻"系统，通过长、中、短期试验，分别研究二氧化碳浓度及水温升高的联合作用下藻类病毒的吸附率、裂解周期、释放量及宿主藻对病毒和病毒核酸的修复率及修复条件，并通过围隔试验在湖泊原位研究二氧化碳浓度升高对噬藻体PP增殖能力及野生宿主修复能力的影响，建立二氧化碳浓度增加条件下藻类病毒增殖速度与修复率变化的数学模型，从而推测二氧化碳浓度增加对藻类病毒生态功能的影响。

噬藻体是感染蓝藻的病毒，其具有重要的生态功能。大气中CO2浓度在未来世纪预计将增加近一倍。以前较多的研究主要是集中在海洋中浮游藻类对大气中CO2浓度升高的生理响应，而CO2升高对淡水藻类甚至对噬藻体的影响还鲜有报道。.本研究以淡水噬藻体PP和及其宿主蓝藻为材料，研究了CO2浓度增加（及相应的温度增加）对噬藻体PP吸附率、裂解周期、释放量以、宿主对受紫外损伤的噬藻体PP的光修复能力及宿主抗噬藻体感染能力的影响。.结果表明：二氧化碳浓度升高会明显影响噬藻体感染宿主蓝藻的感染力和宿主对紫外损伤噬藻体的修复能力和宿主对噬藻体的抗性，且温度升高和二氧化碳浓度的升高对噬藻体感染力的影响具有明显而复杂的交互效应（联合作用）。.上述结果说明二氧化碳浓度升高可以改变噬藻体的增殖动力学过程，并有可能改变未来全球环境变化下噬藻体的生态功能。