The targeted destruction of Karenia brevis through algaecide integration in flocculation and sinking technologies.

Harmful Algal blooms (HABs) of the dinoflagellate Karenia brevis pose a serious threat to the marine and coastal ecosystem. These HAB species synthesize polyether brevotoxins released upon secretion and cell lysis causing significant mortality in marine life. The severe environmental concern necessitates the development of environmentally safe mitigation methods. We address the targeted and rapid destruction of Karenia brevis using the algaecide, calcium peroxide, in tandem with the flocculation and sinking of the algal species.   The incorporation of the algaecide within the floc as granules or affixed to the surface of tubular clays serves to rapidly kill K. brevis minimizing escape from the floc and reentry to the water column. Calcium peroxide reacts with water to form the water-insoluble calcium hydroxide gradually releasing hydrogen peroxide which permeates cell membranes and reacts with intracellular iron to generate hydroxyl radicals toxic to the cell. Additionally, calcium peroxide also serves as a ballast. Pulse amplitude modulated fluorometry results indicate that dose levels as low as 30 mg/L are effective in suppressing photosynthesis destroying cell viability in 3-6 hours. Toxin analysis indicates a significant reduction of toxin levels attributed to Fenton processes. Thus, the proposed technology leads to an inexpensive and scalable technology to mitigate harmful algal blooms of K. brevis. The environmentally benign aspect of calcium peroxide is further substantiated by its eventual conversion to calcium carbonate upon exposure to carbon dioxide.     

Primary Presenter: Vijay John, Tulane University (vj@tulane.edu)

Authors:

Md. Istiak Hossain, Tulane University  (mhossain2@tulane.edu)

Vijay John, Tulane University  (vj@tulane.edu)

Vincent Lovko, Mote Marine Research Laboratory  (vlovko@mote.org)

Richard Pierce, Mote Marine Research Laboratory  (rpierce@mote.org)

Tim Mclean, Tulane University  (tmclean@tulane.edu)