FY 2022 Quinault Indian Nation Lake Quinault Nutrient Enrichment

The project included the following elements: 1) fertilizer purchase and delivery; 2) fertilizing Lake Quinault with liquid nitrogen and phosphorus fertilizers; 3) monitoring of a suite of physical, biological, and water chemistry variables relevant to lake nutrient enrichment effectiveness monitoring (Ashley & Stockner 2003); 4) sample collection and processing; 5) data entry, data QA/QC, and database management; 6) data analysis and reporting; and 7) equipment maintenance/repair and operating expenses. The nutrient prescription was intended to enhance the production of edible phytoplankton and zooplankton, the food source of sockeye fry, while avoiding the occurrence of nuisance algae responses. The fertilizer prescription was developed in February and then applied weekly by boat to the surface waters of Lake Quinault from April to October using a blend of liquid fertilizer consisting of urea ammonium nitrate (UN 32) and ammonium polyphosphate (10-34-0). The limnology monitor was designed to measure sentinel variables that enabled scientists to identify changes in the production cycles of the lake (Stockner 1981 and 1987; Shortreed and Stockner 1985) and chronicle changes in biomass and densities of major plankton components. Shifts in the abundance of species and/or assemblages signaled changes in production, carbon flow, and the food web. The monitor also provided data to identify physical influences that affected lake productivity (e.g. turbidity influence on euphotic zone depth).



The overarching cost of work required concurrent spending of two or more grant awards to complete project tasks for each project period (e.g., March 2023 - May 2024). In addition, annual PCSRF fiscal year funding cycles did not match the project timeline, so there was always an overlap in the use of funds from year to year. This also helped to maintain continuity of the project (by avoiding work stoppages due to lack of funds) over multiple years. This grant funding was expected to help maintain the project into 2025. Both fertilizer costs and operating costs were expected to increase each year due to inflation and market values of fertilizer. The fertilizer UN 32 (ammonium-nitrate) in particular, had increased 27.1% since 2019. This was due to the manufacturing process and the cost of base material, which was natural gas. Unrest in the world, particularly the loss of natural gas exports from Russia due to sanctions, resulted in a significant increase in the cost of UN 32 in 2022. In summary, even though that years award was substantially larger than in previous years, due to the way the project was funded and due to increased material costs, metric reporting remained the same as in prior years.

The purpose of the project is to 1) supplement natural nutrient loads to Lake Quinault and 2) improve trophic level productivity and 3) increase Lake Quinault carrying capacity for juvenile sockeye salmon. Increased primary productivity is the most consistent measure of nutrient supplementation response in lakes. The prescribed nutrient load is equivalent to a yield of approximately 0.9 ug/L of chlorophyll a biomass. The project team will analyze and evaluate the data collected to identify seasonal productivity and report the trophic state of Lake Quinault.