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Pollute at Your Own Risk: Where We Stand in the Cause of Red Tide

By Loret Haas-Hanser

In its entirety, the ocean covers over 70% of the planet, and is home to 50-80% of all life on earth. Constituting the largest ecosystem in the world, it is not shocking that the ocean copes with many issues impacting the chemistry, quality, and life that swims betwixt the waves. Marine pollution is a commonly addressed issue that has become a topic of priority in the past few decades, and rightfully so. Pollution on any and every level is causing irreversible damage to our planet’s oceans, and it can be directly correlated to human neglect. Plastic, gasoline, sewage and other miscellaneous pollutants are constantly barraging the ocean. However, new evidence suggests that chemical pollutants, specifically aerosols, are more detrimental than previously anticipated, as they are proactively damaging life in the ocean by increasing harmful algae blooms such as red tide.

Algae exists as a divergent faction of single-celled photosynthetic organisms, some of which can be ecologically beneficial. Certain algae provide nutrient cycling, and aid the production of oxygen and are integral to maintaining a healthy oceanic environment. However, other branches of algae can be incredibly toxic. “Red tide” is the general term used to describe a harmful algal bloom (HAB), which is constituted by overgrowth of algae and phytoplankton known as dinoflagellates. Dinoflagellates play a large role in maintaining oceanic homeostasis, as their presence depends on variables such as temperature and salinity. The effects of red tide can be incredibly degenerating, and in extreme circumstances, can be fatal for marine life and can cause serious issues such as respiratory, gastrointestinal and neurological problems in humans when exposed.

Artwork by Peter Amador of the University of Miami

Through research on atmospheric processes, researchers have concluded that aerosols can be absorbed and deposited onto the ocean surface. As a form of pollution, aerosols in the ocean manipulate oxygen levels and increase acidity (pH). Interestingly, aerosols, once absorbed, can additionally increase solubility for other chemicals and metals such as iron. By increasing the usage of aerosols, we are actively feeding more metal and harmful compounds into the ocean. This in turn, feeds into harmful algae blooms such as red tide.

Algae is an organism that can be beneficial to oceanic environments when produced in normal capacity. Unfortunately, overgrowth of any algae can have harmful implications on the ocean. Algae and minute factors of the ocean are not variables humanity commonly thinks about. When we think of the ocean, we think of coral reefs, sharks, commercialized types of fish like salmon and tuna, and activities such as family vacations, fourth of July, and other memorable gifts given to society by the ocean. Thinking about bacteria, microorganisms and algae is not common- they are so minute that they slip past our knowledge, which is a mindset that needs to end. Algae is a necessary component to maintaining homeostasis in the ocean. Every red tide outbreak kills fish, changes salinity and acidity and can have detrimental health effects on humans. Existing as the largest ecosystem on the planet, giving sustenance and life to billions on a global scale, the ocean deserves respect from humankind.

A note from the author: As a Florida native, I spent weekends and holidays on the beach throughout my adolescence. I’ve seen the damage humans inflict on the ocean firsthand. Oil spills, plastic, algae blooms, waters littered with dead’s devastating. Please be thoughtful and consider your actions in relation to the ocean. Decrease the use of plastics, properly dispose of chemicals, cut down on aerosols (the ocean and equator will thank you for this one), and most importantly, be cognizant of the impact that you can have on this planet.


Mahowald, N. M., Hamilton, D. S., Mackey, K. R., Moore, J. K., Baker, A. R., Scanza, R. A., & Zhang, Y. (2018). Aerosol trace metal leaching and impacts on marine microorganisms. Nature communications, 9(1), 2614.

Ito, T., Nenes, A., Johnson, M. S., Meskhidze, N., & Deutsch, C. (2016). Acceleration of oxygen decline in the tropical Pacific over the past decades by aerosol pollutants. Nature Geoscience, 9(6), 443.

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