Controlling Lyngbya wollei in three Alabama, USA reservoirs: summary of a long-term management program

Abstract

Abstract Large-scale Lyngbya wollei (Cyanobacteria, Oscillatoriales) infestations are increasing throughout the USA and globally and causing significant obstruction of water resource uses. Decision makers and stakeholders encountering this nuisance organism often seek management options. Many approaches to L. wollei management may be ineffective or not applicable to specific field sites. Chemical control with United States Environmental Protection Agency registered algaecides has shown to be effective, although the specific formulation, concentration, and application frequency can all govern efficacy. This study summarizes results from a long-term and adaptive management program on extensive L. wollei infestations in three central Alabama, USA reservoirs (Lay Lake, Jordan Lake and Lake Mitchell) managed by Alabama Power Company. Multiple treatment strategies including numerous algaecides, combinations and addition of surfactants were used in attempts to control the nuisance cyanobacterium and preserve multiple beneficial functions of the resource. Ultimately, operational shift toward one technology, a double-chelated copper algaecide with surfactants and emulsifiers (Captain® XTR) resulted in more efficient and economical control. There were significant (P < 0.05) decreases in historic L. wollei acres requiring treatment through time on each reservoir. Throughout this study period, a 51.4, 88.1 and 94.7% percent decrease in total nuisance acres treated was realized on Lay Lake, Jordan Lake and Lake Mitchell, respectively. The large-scale and long-term dataset presented herein, covering multiple candidate treatment programs, provides valuable information to guide management decisions on other water resources impacted by L. wollei infestations.

Keywords

• Lyngbya wollei
• Cyanobacteria
• Management
• Algaecide
• Copper