Zooplankton trophodynamics and spatial patterns in estuarine transition zones

生态系统被认为是由相互关联的异质亚基组成的开放系统。这些亚基包含随时间变化的食物网，其营养相互作用提供了从较低营养水平到消费者和捕食者的能量和物质的途径。与此同时，环境空间复杂性和通过主动和被动运输过程的相互联系（例如，生物体的分散、通过资源的能量运输）现在被认为改变了种群和群落的动态，并最终维持了生物多样性。本研究计划旨在了解二级（浮游动物）生产力的控制，通过考虑河口景观的空间离散栖息地之间的营养连接的程度，以及这种交流如何在季节尺度上变化。一些相互关联的短期目标将得到解决，重点是在圣劳伦斯河口河口过渡带的营养动力学和栖息地连接的特定方面：（1）浮游动物组合的季节性演替在栖息地排列沿着（例如，盐度）和横跨（浅滩与深生境）的河口在一年中的不同时间将被确定。(2)次级生产力的重点是各种生境类型的物种组合内的营养联系将被确定。(3)潜在的补贴和栖息地之间的营养耦合程度将被量化，重点是在能量转移中发挥重要作用的物种子集。(4)将利用现场和实验室实验测量营养联系的比率和强度。(5)从长远来看，我们的目标是开发一个耦合的生物物理模型，估计在原位本地生产和补贴之间的运输栖息地整体河口次级生产的相对重要性。本研究提出了两个主要项目，一个侧重于整体浮游动物生产，放牧和捕食的浮游动物在河口过渡带的异质空间。第二个重点是时间和空间的变化，其原因和优势桡足类和中等大小的捕食者（糠虾）之间的关系，以整体次级生产力的重要性。

Ecosystems are considered to be open systems composed of inter-related heterogeneous subunits. These subunits contain food webs that vary in time and whose trophic interactions provide the pathways of energy and matter from lower trophic levels to consumers and predators. At the same time environmental spatial complexity and interconnectivity via active and passive transport processes (e.g., dispersion of organisms, energy transport through resources) are now recognized to alter population and community dynamics and ultimately maintain biological diversity. This research program aims to understand the control of secondary (zooplankton) productivity by considering the degree of trophic connectivity among spatially discrete habitats of the estuarine landscape and how such exchanges vary on a seasonal scale. A number of interrelated short-term goals will be addressed, focussing on particular aspects of tropho-dynamics and habitat connectivity in the estuarine transition zone of St Lawrence Estuary: (1) Seasonal succession of zooplankton assemblages in habitats arrayed along (e.g., salinity) and across (shoal vs. deep habitats) the estuary at different times of the year will be determined. (2) Secondary production by focussing on trophic linkages within species assemblages of various habitat types will be determined. (3) Potential subsidies and the degree of trophic coupling among habitats will be quantified, focussing on a subset of species that play a major role in energy transfer. (4) Rates and strength of trophic linkages will be measured using in situ and laboratory experiments. (5) In the longer term, we aim to develop a coupled biological-physical model to estimate the relative importance of in situ local production and subsidy transport among habitats to overall estuarine secondary production. This research proposes two main projects, one focussing on overall zooplankton production, grazing and predation of zooplankton in the heterogeneous space of the estuarine transition zone. The second one focuses on temporal and spatial variability, its causes and importance of relationships between dominant copepods and intermediate sized predators (mysids) to overall secondary productivity.