Ultrasonic Pore Formation in Harmful Algal Blooms

Abstract

A presentation about this thesis was awarded third place in the One Water Fresh Ideas Conference, One Water Ohio, August 2025.Harmful Algal Blooms (HABs) are an emerging problem in drinking water treatment, recreation, and marine ecosystem health. One proposed control method for HABs is the use of low power ultrasound. However, we do not yet understand whether this treatment method works, or by what mechanism. A potential mechanism is temporary pore formation in algae due to ultrasound exposure, or sonoporation. Sonoporation could facilitate algae treatment by allowing chemical algaecides or stressors to enter cells. The objective of this project was to determine whether sonoporation occurs in algal cells and could reasonably occur under low power ultrasound. To test this, we exposed nontoxic Anabaena and Microcystis sp. to ultrasound at four different frequencies and several power levels. Sonoporation was observed in Microcystis sp. at a frequency corresponding to medical literature above the cavitation threshold. No sonoporation was observed below the cavitation threshold or in filamentous Anabaena sp. Sonoporation can occur in algae, but is not a feasible mechanism for controlling algae with low power ultrasound.The US Army Corps of EngineersDepartment of Civil, Environmental, and Geodetic Engineering Summer Undergraduate Research FellowshipA three-year embargo was granted for this item.Academic Major: Environmental Engineerin