Biodiversity and ecosystem function of Arctic marine microbial food webs

海洋单细胞浮游植物负责地球一半的氧气生产，它们是组成海洋微生物食物网的微生物群落复杂组合的一部分。这些网的功能多种多样，除了初级生产者外，它们还包括初级和次级食草动物、捕食者、寄生虫、有害动物以及使有机氮、碳和其他元素矿化的化学合成微生物。这些微生物群落是北冰洋所有高等食物网的基础，并影响从浮游动物到海豹的北极海洋动物的生命周期，这些生命周期与关键生命阶段特定食物来源的可预测出现密切相关。我的研究的主要目标是确定物理海洋条件和微生物组合之间的关系。我们将通过将分子生物学方法与其他生物和物理海洋观测相结合来解决这些问题和相关问题。这项研究将为各级HQP提供培训，并将包括四个博士项目。第一个将识别微生物食物网复合体，并将对复合体中的碳和能量路径进行建模。由于氮的供应及其生物转化在很大程度上决定了北极的净初级生产力，第二个学生将开发针对关键基因编码的序列的协议，以估计和描述生物地理省份的多样性氮过程。北极的盐度高度分层，第三个项目将研究主要水团中心的氮素加工基因，那里的条件变化很慢，并将这些基因与海水密度梯度上的相同基因进行比较，那里的条件变化很快。第四个博士项目将进行实验室和田间实验，以确定作用于指示物种及其基因表达的生态过滤器。这项研究将利用新兴技术，对寒冷海洋生态系统的结构和功能以及北极海洋群落和食物网将如何应对该区域不断加速的气候变化产生更好的预测性理解。

Marine single celled phytoplankton are responsible for half of the planet's oxygen production, and they are part of the complex assemblages of microscopic communities than make up marine microbial food webs. These webs are functionally diverse and in addition to the primary producers they contain primary and secondary grazers, predators, parasites, detritivores, and chemosynthetic microorganisms that mineralize organic nitrogen, carbon and other elements. These microbial communities are at the base of all higher food webs in the Arctic Ocean, and affect the life cycles of Arctic marine animals from zooplankton to seals, which are strongly linked to the predictable appearance of specific food sources during critical life stages. The major goal of my research is to define relationships among physical oceanographic conditions and microbial assemblages. We will address these and related questions by combining molecular biological approaches with other biological and physical oceanographic observations. This research will provide training for HQP at all levels and will include four PhD projects. The first will identify microbial food web complexes and will model carbon and energy pathways within the complexes. Since nitrogen supply and its biological transformations largely determine net primary productivity in the Arctic, the second student will develop protocols to target sequences coding for key genes to estimate and describe the diversity nitrogen processes across biogeographic provinces. The Arctic is highly salinity stratified and the third project will investigate nitrogen processing genes at the center of major water masses, where conditions change only slowly, and will compare these to the same genes along seawater density gradients, where conditions change rapidly. The fourth PhD project will run laboratory and field experiments to determine the ecological filters acting on indicator species and their gene expression. This research will harness emerging technologies to generate improved predictive understanding of the structure and functioning of cold ocean ecosystems, and of how Arctic marine communities and food webs will respond to accelerating climate change in the region.