Ecological processes influencing zooplankton productivity in highly dynamic estuarine transition zones

河口过渡带是淡水和咸水的混合，是全世界整个河流系统的关键交错带。这些生态系统在生物生产力方面具有很高的生态价值，这在很大程度上是由河口再循环、潮汐混合和淡水排放等物理特性驱动的。圣劳伦斯河口过渡区是甲壳类动物和具有重要商业价值的鱼类的重要保留区和育苗区。这种高能量和复杂的河口生态系统的高生产力和时空异质性使其成为研究生境互连对营养关系和生物过程的影响的理想场所。即使人们认识到种群和群落动态受营养相互作用和被动和主动运输过程的调节，这些过程决定了环境的空间复杂性和相互连通性(例如，资源的分散、生物的迁徙)，但这些过程在河口的整体生态系统意义尚未得到很好的理解。我的研究计划的目的是通过考虑种内遗传多样性、营养动态和河口海景离散生境之间的连接度来了解次生(浮游动物)生产力的控制机制。我的目标是大大提高我们对浮游动物次级生产力模式的科学理解，因为这一知识对于以生态系统为基础的管理方法中海洋资源的养护和可持续利用以及生态系统健康至关重要。同时，这种知识对于补充我们对从初级生产到第三级营养水平的营养周转的理解是必要的，因为浮游动物通常代表较高营养水平(例如鱼类)的营养基础。我们将重点关注最重要的河口物种，如桡足类、Mysids和鱼类幼虫。我们将确定Eurytemora affinis次级生产的时间和空间变异性与整个河口过渡带的遗传多样性和营养相互作用之间的联系。我们将估计慈竹分支和移动消费者(Mysids、鱼苗)之间的营养相互作用的程度。关于慈竹枝条生产力和营养联系强度的结果可能有助于预测这一重要育苗区的幼鱼补充。这对于重新引入的条纹鱼的管理将是重要的。

Estuarine transition zones, were freshwater mixes with saltwater, are critical ecotones for entire river systems worldwide. These ecosystems have a high ecological value in terms of biological productivity which is strongly driven by physical properties such as estuarine re-circulation, tidal mixing and freshwater discharge. The St. Lawrence estuarine transition zone represents important retention and nursery zones for crustaceans and commercially important fishes. The high productivity and spatiotemporal heterogeneity of this highly energetic and complex estuarine ecosystem makes it an ideal site to study the influence of habitat interconnectivity on trophic relationships and biological processes. Even if it is recognized that population and community dynamics are regulated by trophic interactions and passive and active transport processes that determine environmental spatial complexity and interconnectivity (e.g., dispersion of resources, migration of organisms), the overall ecosystem significance of these processes in estuaries is not well understood. The objective of my research program is to understand the control mechanisms of secondary (zooplankton) productivity by considering intraspecific genetic diversity, trophodynamics and the degree of connectivity among discrete habitats of the estuarine seascape. I aim to significantly advancing our scientific comprehension of zooplankton secondary productivity patterns, as this knowledge is of crucial relevance to the conservation and sustainable utilization of marine resources and ecosystem health in an ecosystem-based management approach. At the same time, this knowledge is essential to complement our understanding of the trophic turnover from primary production to tertiary trophic levels, as zooplankton often represents the nutritional basis for upper trophic levels (e.g. fish). We will focuss on the most important estuarine species, such as copepods, mysids and fish larvae. We will determine links between the temporal and spatial variability in Eurytemora affinis secondary production, and genetic diversity and trophic interactions throughout the estuarine transition zone. We will estimate the degree of trophic interactions between E. affinis clades and mobile consumers (mysids, fish larvae). Results on E. affinis clade productivity and the strength of trophic linkages may help predicting larval fish recruitment in this important nursery zone. This will be of importance for the management of the re-introduced striped bass.