微囊藻对浮游动物的食物贡献及机理研究

蓝藻水华，尤其是微囊藻水华泛滥及其危害已经引起国内国际社会的高度重视。生态学家普遍认为微囊藻水华抑制了初级生产力向初级消费者的物质与能量传递。其论据包括有微囊藻的尺寸不适口和异养关键营养缺乏等。与之矛盾的是，自然湖泊中存在大量浮游动物和微囊藻水华并存的事实，以及野外稳定同位素调查中显示的微囊藻可以是湖泊浮游动物碳源重要来源的结论。针对该矛盾，项目组提出假设：微囊藻经由微生物转化（细菌减少尺寸，提供能量补贴；异养鞭毛虫合成关键营养），最终满足浮游动物的生长繁殖需求并间接对浮游动物形成食物贡献。为验证假设， 项目组从室外人工系统模拟和室内控制实验两方面入手 ，采取稳定同位素探针、分子（生化）生物标签等技术手段来追踪检验浮游动物对微囊藻的利用效率与途径，探索其相关机理。该项研究可以加深我们对水华期间的食物网结构的理解，以及对微囊藻水华生消过程的认识，并最终为微囊藻水华的控制提供理论依据。

Cynobacteria bloom, especially Microcystis bloom has drown highly attention worldwide. Ecologists believe that Microcystis bloom restrains the material and energy transfer from primary producers to primary consumers. Part of the reason lies on that zooplankton can hardly ingest Microcystis because of its inappropriate size, lack of key nutrients (such as polyunsaturated fatty acids) and etc. Controversially, coexistence of both two in large number are common phenomenon in nature. Previous table isotope investigations also indicated that Microcystis can be an important carbon resource for zooplankton. In the case we propose the hypothesis that Microcystis will eventually meet the growth and reproduction needs of zooplankton via microbial transformation (bacteria decomposition reduces size and provides energy subsidies; heterotrophic flagellates synthesizes key nutrimental components), and make an indirectly food contribution to zooplankton. In order to test the hypothesis, the project team intend to use both outdoor mesocosms and lab control experiment, and apply (single molecular) stable isotope probe, molecular (biochemical) biomarker analysis and other technical means to track and test the efficiency and potential pathways of Microcystis carbon transfer to zooplankton, as well as the mechanisms. This study can deepen our understanding of the pattern of food web structure in the process of Microcystis bloom development, providing theoretical basis for the control of Microcystis bloom eventually.