Harmful algal blooms (HABs) are increasingly reported across the southern United States, leading to fish, livestock, and companion animal deaths, losses in agricultural productivity, and interruptions in domestic water supplies. This rise is attributed to improved identification and monitoring but is also likely exacerbated by environmental changes, particularly the high heat and prolonged droughts that concentrate nutrients and diminish water availability for flushing. HABs, including those caused by Microcystis aeruginosa, thrive in hot, nutrient-rich, stagnant conditions.
Traditional management strategies, such as nutrient control, flushing, algaecides, and toxin oxidation, face significant limitations. Nutrient management is costly and impractical for large water bodies, flushing is unfeasible under drought conditions, and algaecides are expensive and must be applied precisely before toxin production escalates. Similarly, oxidizing toxins with potassium permanganate is both costly and potentially harmful to aquatic life. These challenges have highlighted the need for cost-effective, sustainable alternatives, such as humic acid.
Humic acid, an organic compound derived from natural decomposition, offers promising potential for HAB management. Previous studies on Prymnesium parvum demonstrate it can be used prophylactically to prevent blooms, disrupt algal cell processes, and bind nutrients. By providing a carbon source for beneficial bacteria, humic acid may enhance natural nutrient cycling and reduce conditions conducive to algal proliferation.
This presentation will explore the evaluation of humic acid as a management tool during blooms of M. aeruginosa. Results on humic acid use as a treatment, prophylactic preventative, and nutrient binder when used during M. aeruginosa blooms will be shared, focusing on its practical applications and potential to serve as a low-cost, environmentally sustainable alternative to traditional HAB management strategies.