Biodiversity and ecosystem function of Arctic marine microbial food webs

海洋单细胞浮游植物负责地球上一半的氧气生产，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。这些网在功能上是多样的，除了初级生产者之外，它们还包含初级和次级食草动物、捕食者、寄生虫、食草动物和使有机氮、碳和其他元素矿化的化能微生物。这些微生物群落是北冰洋所有高级食物网的基础，影响着从浮游动物到海豹的北极海洋动物的生命周期，这与关键生命阶段特定食物来源的可预测出现密切相关。我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。我们将通过结合分子生物学方法和其他生物和物理海洋学观测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。第一个将确定微生物食物网复合体，并将模拟复合体中的碳和能量途径。由于氮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，第二名学生将制定协议，以目标序列编码的关键基因，以估计和描述跨地理省份的多样性氮过程。北极是高度盐度分层的，第三个项目将调查主要水团中心的氮处理基因，那里的条件变化缓慢，并将这些基因与沿着海水密度梯度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实地实验，以确定生态过滤器对指示物种及其基因表达的作用。这项研究将利用新兴技术来提高对冷海洋生态系统结构和功能的预测性了解，以及北极海洋群落和食物网将如何应对该地区加速的气候变化。

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.