Microcystin Shows Thresholds and Hierarchical Structure With Physicochemical Properties at Lake Fayetteville, Arkansas, May Through September 2020

Highlights Despite little to no dissolved nutrient supply in surface water, harmful algal blooms are sustained throughout the 2020 growing season. Sediment phosphorus release was high a lake that has annual blooms, and it is an important piece of watershed management puzzle. Thresholds hierarchical structure with individual physicochemical properties pigment fluorescence at this explain large portion microcystin variability. Abstract. Harmful (HABs) freshwaters global concern, research focused on drivers cyanobacterial growth toxin production. We explored importance nutrients HABs producing measurable Lake Fayetteville, Arkansas, USA. The specific objectives were (1) quantify sediment (P) flux estimate potential equilibrium P concentrations (EPC0) July 2020, (2) assess water quality conditions from March through September (3) evaluate thresholds (or change points, CPs) total concentrations. sediments source under both oxic anoxic conditions, SRP continuously less than EPC0 estimated for bottom (~0.03 mg L-1); likely Fayetteville. changes Fayetteville over season typical small, hypereutrophic reservoirs, low biomass winter when greatest as diminished into Microcystin elevated above 1 µg L-1 mid-June mid-August most parameters study showed or points microcystin. Hierarchical existed concentrations, showing biomass, N supply, Nutrients raw explained 83% variation during (both P) external internal sources these toxicity Keywords: Algal Blooms, Nutrient Drivers, Phosphorus Release, Water Quality.