Marine Derived Nutrients in Freshwater Systems – Anadromous Fishes and the Nutrient Cycle

The role of marine derived nutrients (MDN) in freshwater ecosystems has been the focus of extensive scientific investigations. This body of research examines the structure and function of nutrient cycles associated with MDN transported by anadromous fishes returning from the ocean to freshwater systems. A complex interaction of nutrient and trophic pathways characterize ecosystems influenced by MDN and related research encompasses a broad spectrum of disciplines from biogeochemistry and paleolimnology, to trophic ecology and population dynamics. Research results from each of these areas add to our understanding of the role that MDNs play in aquatic, riparian, and terrestrial productivity. For example, various nutrient tracking methods have revealed a surprising omnipresence of MDNs in everything from dissolved nutrients to aquatic and terrestrial plants, invertebrates and vertebrates. Clarifying the role of MDN in freshwater and terrestrial environments has proven crucial to understanding ecosystem function and how it relates to resource management. A variety of lake and stream fertilization programs which replace or augment MDN are now common practice using both organic (carcasses) and inorganic (refined chemical) nutrient additions as restoration or enhancement tools. In the course of developing these techniques their efficacy has been tested and both positive and negative outcomes have been identified. This symposium will present the latest research in the field of MDN ecology and will review efforts and applications related to this unique ecosystem function.