Discontinuous Grazing Pressure by Microzooflagellates on Marine Synechococcus

小型浮游植物在初级生产中起着重要作用， 海洋 单细胞蓝细菌聚球藻是一种 这个社区的杰出和重要的成员， 细胞密度超过每升10万个细胞， 每天3倍的原位生长速率，因此可以 占总初级生产力的5%至25%， 温带和热带海洋。 迄今为止的研究表明， 聚球藻以与其生长速度相当的速度被放牧， 微鞭毛虫是负责将 聚球藻的生物量。 聚球藻有一个特点 在自然界和培养中的不连续的昼夜生长模式 可以通过直接和间接的方法进行监测。 结果 实验测量生长和放牧率 藻海中的聚球藻导致了一种假设， 微鞭毛虫对聚球藻的掠食可以是周期性的， 主要发生在晚上。 为了验证这个假设，博士。 沃特伯里将分离并鉴定微鞭毛虫 负责聚球藻周转并记录其对 聚球藻丰度的时间模式 该项目将 在近海和公海沃茨进行， 实验性地采用直接和间接的培养技术， 用直接电池测量原位生长和掠动速率 计数和C-14碳酸氢盐掺入。 的意义 这项研究不仅仅是为了加深我们对 海洋聚球藻的生态学 这个单细胞的 光合细菌是海洋生物的重要组成部分， 微生物食物网关于身份的见解 食草聚球藻与放牧模式和速率 聚球藻可以作为一个模型，并提供重要的见解 进入"微生物循环"的运作。//

Small phytoplankton play a major role in the primary production of the oceans. The unicellular cyanobacterium Synechococcus is a prominent and important member of this community that can reach cell densities of more than 100 thousands cells per liter, achieve in situ growth rates of 3 doubling per day and as a result may contribute between 5 and 25% of the total primary productivity in the temperate and tropical oceans. Studies to date indicate that Synechococcus is grazed at rates comparable to its growth rate and that microflagellates are the major group responsible for turning over Synechococcus biomass. Synechococcus has a characteristic discontinuous pattern of diel growth both in nature and in culture that can be monitored by direct and indirect methods. Results of experiments measuring both growth and grazing rates of Synechococcus in the Sargasso Sea led to the hypothesis that grazing of Synechococcus by microflagellates can be periodic, occurring primarily at night. To test this hypothesis, Dr. Waterbury will isolate and characterize the microflagellates responsible for Synechococcus turnover and document their impact on the temporal patterns of Synechococcus abundance. The project will be conducted in both inshore and open-ocean waters and will experimentally employ culture techniques, direct and indirect measurements of in situ growth and grazing rates using direct cell counts, and C-14 bicarbonate incorporation. The significance of this study extends beyond simply furthering our understanding of the ecology of marine Synechococcus spp. This unicellular photosynthetic bacterium is an important component of the marine microbial food web. Insights concerning the identity of Synechococcus grazers and patterns and rates of grazing on Synechococcus can act as a model for and provide important insights into the workings of the "microbial loop".//