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

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.

Spatial and Temporal Variation in Paralytic Shellfish Toxin Production by Benthic Microseira (Lyngbya) wollei in a Freshwater New York Lake

Butterfield Lake is a mesotrophic lake in New York State where residents and pets have experienced unexplained health issues. Microseira wollei (basionym Lyngbya wollei) was found at two of 15 sites in Butterfield Lake and analyzed for microcystins, anatoxins, cylindrospermopsins, and paralytic shellfish poisoning toxins (PSTs). Only PSTs and trace levels of anatoxin-a were detected in these samples. This is the first published report of PSTs within a New York State lake. To evaluate the environmental and temporal drivers leading to the observed toxicity, PST content at the two sites was examined in detail. There were distinct differences in the total PST content, filament nutrient, filament chlorophyll, and relationship to environmental drivers between the sites, as well as distinct differences in the total PST content measured using different analytical techniques. A multivariate model containing site, temperature, and filament chlorophyll explained 85% of the variation in PSTs observed over the growing season. This work emphasizes the importance of proper site selection and choice of analytical technique in the development of monitoring programs to protect lake users from the occurrence of benthic cyanobacteria toxins.