The movement of marine-derived nutrients from a salmon spawning river to a nursery lake

Abstract

Salmon play a key role in the redistribution of marine-derived nutrients (MDNs) in aquatic and terrestrial ecosystems. Research conducted on the movement and storage of MDNs in aquatic systems throughout the Pacific Northwest seem to vary in whether MDNs have a beneficial, neutral, or detrimental impact. Using Horsefly Bay (Quesnel Lake), the mechanism and driving factors for the delivery and dispersion of MDNs were evaluated. Higher concentrations of marinederived nitrogen and carbon were found to enter this nursery system in the fall spawning period. However, due to the increased water discharge, it was found that the load of marine-derived nitrogen and carbon was higher during the spring freshet study period. These increases in MDNs were found to correlate with chlorophyll-a and fluorescence levels which indicate increases in productivity. Increased production can support the growth and survivorship of juvenile salmon rearing in this nursery system through bottom-up trophic transfer.