FY 2014 Lake Quinault Nutrient Enrichment

The project elements funded by the grant include 1) fertilizing Lake Quinault with liquid nitrogen and phosphorus; 2) monitoring of a suite of physical, biological, and chemical variables relecant to lake nutrient enrichment effectiveness monitoring (Ashley & Stockner, 2003) ; 3) data entry, data QA/QC, and database management; and 4) equipment maintenance/repair and operating. Tasks 1-3 are carried out under contract. The nutrient prescription is intended to enhance production of edible phytoplankton and zooplankton, the food source of sockeye fry, while avoiding the occurrence of nuisance algae responses. The prescribed nutrient load was developed and applied weekly by boat from April to October to the epilimnion of Lake Quinault through application of liquid fertilizers urea-ammonium nitrate (32-0-0) and ammonium polyphosphate (10-34-0). The monitor is designed to measure the sentinel variables that enable scientist to identify changes in the production cycles of the lake (Stocknet, 1981,1987, Shortreed and Stockner, 1985). This information will chronicle changes in the abundance and biomass of major plankton components. Shifts in abundance of species, and/or assemblages will signal changes in production, carbon flow, and the food web. The monitor will also provide data to identify physical influences that impact lake productivity (e.g. turbidity influence on euphotic zone depth).

Post-season reporting from 13-QUIN-02 overlapped with the start of this project.

The project benefits (objectives) are 1) supplement natural nutrient loads to Lake Quinault and 2) improve trophic level productivity and lake carrying capacity for sockeye fry. Increased primary productivity is the most consistent measure of nutrient supplementation response in lakes. The prescribed nutrient load is equivalent to a yield of 0/6 ug/L chlorophyll a biomass. QIN will analyse and evaluate the data collected to identify seasonal productivity and report the trophic state of Lake Quinault.