Grant: Discovery Grants Program - Individual

Estuarine transition zones, where freshwater mixes with saltwater, are critical ecosystems 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 Estuary, part of Canada's natural heritage, is the important artery between the continent and the Atlantic Ocean. Ecologically, the St. Lawrence estuarine transition zone represents important retention and nursery zones for crustaceans and ecologically 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 connectivity on trophic relationships and biological processes. Even if it is recognized that population and community dynamics are regulated by trophic interactions and transport processes that determine environmental spatial complexity and connectivity, the overall ecosystem significance of these processes in estuaries is not well understood. The goal of my research program is to significantly advance our understanding of the main mechanisms controlling the ecological resilience of zooplankton key species in a highly variable environment. I aim to establish how environmental variability acts on key biological processes involved in production and consumption of zooplankton, that most definitely impact zooplankton population dynamics throughout the estuarine seascape. My research program is based on a food-web seascape approach. We will acquire and combine novel and crucial scientific knowledge on eco-physiology, genetic diversity, trophodynamics and connectivity throughout the estuarine seascape as primary drivers influencing zooplankton dynamics. 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 focus on the most important estuarine species, such as copepods, mysids and fish larvae to disentangle the relationships between spatio-temporal production patterns, plasticity, genetic diversity and trophic coupling of the dominant copepod species complex Eurytemora affinis and its mysid and fish (smelt, striped bass) predators. This research program will significantly advance our scientific comprehension of zooplankton 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.