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The Toxic Algae in Our Water
ONC Editorial

Aug 28, 2023

To prevent any further social, environmental and economic damage from algal blooms, we need prevention strategies. (The opinions expressed in this article are those of the individual author, Annie Llombart, whose information can be found below.)

It's true that algal blooms, or overgrowths of algae in a body of water, can sometimes occur naturally. But this hardly absolves them of danger. Human activity has significantly increased the rate at which these blooms are growing. This results in an excessive amount of algae overgrowth, filling our waters with toxins. 

Climate change is leading to increases in water temperatures, the salinity of freshwater sources, CO2 levels in the air and sea level and coastal upwelling. According to the U.S. Environmental Protection Agency (EPA), all of these are optimal conditions for harmful algal blooms to arise and propagate. Additionally, increased urban and agricultural runoff from expanding human settlements is providing excess nitrogen food for these algae to thrive. Since this is a “human-caused” problem, it requires a human-led solution.

There are many strategies currently in place to mitigate harmful blooms. These include chemical methods (copper, barley straw and biosurfactants), biological methods (predator enhancement, macroalgae and viruses), and physical methods (removing the algae, column mixing and flocculation). 

That being said, these methods of mitigation do not always prevent damage. In Florida, for example, the manatee population has been starving and dying as a result of an excess of hundreds of algal blooms during 2022. The blooms cut off sunlight to the marine floor, prevent water oxygenation and compete for nutrients and other resources needed by seagrass, the manatees’ main food source. 

These overgrowths also affect humans. According to the Centers for Disease Control and Prevention (CDC), in 2019, 24 algal blooms caused a total of 63 counts of human illness. 

Not only do these plants affect human health, but mitigation strategies are also costly. In the last decade, the U.S. has spent over $1.1 billion on algal bloom cleanups across the country. This is without counting the healthcare costs of the people and animals who fell ill, nor the economic loss of people who depend on certain water bodies for income (fisheries, waterside restaurants, etc.). 

If we seek to prevent any further social, environmental and economic damages, we need to focus on implementing prevention strategies. 

Such strategies, at a local level, could include picking up and disposing of pet waste, installing rain barrels to capture water runoff, using strategic landscaping techniques (for example, xeriscaping) to increase runoff filtration, incorporating native vegetation around and near water bodies, airing bodies of water and disposing of garden waste to prevent decomposition near water. 

On a larger scale, the issue traces back to agricultural and urban practices. At this level, it would be necessary to build conservation buffers, limit livestock access to waterways, and implement high-efficiency watering technologies, all in order to prevent agricultural runoff.  

These are just some available strategies. Research efforts should be scaled up in order to effectively prevent an exponential increase in algal overgrowths. These plants are already spawning beyond their usual season. These actions will need to accompany larger climate efforts, as the best prevention for algal blooms is to halt climate change. 

Academics and policymakers should consider working collaboratively to regulate agricultural and urban runoff and to help local communities recognize and fight algal blooms in homes and in smaller bodies of water. Doing nothing will only incur devastating consequences for humans, wildlife and ecosystems.

Annie Llombart is a University of California Santa Cruz graduate with majors in Politics and Environmental Studies and a minor in History. She focused her studies on environmental policy, international relations and sociology. She has also worked at the United Nations with the Spanish delegation on the 2030 Agenda for Sustainable Development and as sustainability coordinator for Fundación Alternativas, a Spanish think tank. She is currently a law school candidate and seeks to pursue a degree in environmental law.


Abbott, Chuck. "Algae Blooms Have Cost at Least $1.1 Billion over past Decade, Says EWG." Successful Farming, 27 Aug. 2020.

Associated Press. "Manatee Deaths Rise in Florida as Algae Blooms, Pollutants Kill Seagrass." Tampa Bay Times, 19 Oct. 2021.

CDC. "Summary Report – One Health Harmful Algal Bloom System (OHHABS), United States, 2019." Centers for Disease Control and Prevention, 27 Sept. 2021.

EPA. “Harmful Algal Blooms.” Environmental Protection Agency, 2022,

Solitude Lake Management. "Top 10 Ways: How to Prevent Harmful Algal Blooms and Cyanobacteria." Solitude Lake Management: Full-Service Lake And Pond Management. 26 Apr. 2021.

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