Nutrient Pollution from Industrial Farms is a Major Factor in Florida’s Toxic Algae Crisis

by Kyle Rabin


An extraordinary number of dead and injured marine animals have washed up on Florida’s west coast this summer. The cause? A devastating bloom of toxic algae which is to blame for killing dolphins, sharks, manatees, sea turtles and many other marine animals. Even a large whale shark is believed to be a victim of this particular toxic algal bloom known as “red tide.”

The ominous name comes from the rust-red hue associated with thick concentrations of a microscopic alga (a plantlike organism) named Karenia brevis. In addition to the destructive impact it has taken on wildlife, it is being blamed for triggering respiratory health problems for humans, especially for people with asthma. The toxins produced by the red tide, called brevetoxins, can become airborne, and when they’re blown ashore — sometimes miles inland — they can cause difficulty breathing as well as other symptoms. Residents and tourists alike have suffered.

While Florida has been dogged in the past by red tides, this year’s bloom has been particularly persistent. It began in November of last year, making it the longest running bloom for the Gulf of Mexico in over a decade. Given the red tide’s damage and ongoing threat to the environment, human health and the local economy (the tourism industry, in particular, has felt the pain), Governor Rick Scott declared a state of emergency for seven counties stretching from Tampa Bay south to the Florida Keys. The red tide isn’t the only bloom affecting the state as there are others occurring further inland, like the one affecting Lake Okeechobee and the waterways it empties into. These blooms are so bad that they have figured prominently in the US Senate race between incumbent Sen. Bill Nelson (D) and his Republican challenger, Gov. Rick Scott. Each has been blaming the other for not doing enough to confront the toxic algae crisis.

What’s Making These Algal Blooms Worse? Agriculture

The primary causes of an algal bloom are excess nutrients in the water, like phosphorus and nitrogen, that act as fuel for a population explosion of algae. These outbreaks along Florida’s Gulf Coast are intensified and prolonged by nutrient pollution from mismanaged agricultural and urban runoff and, in some instances, failing or poorly maintained sewage and septic systems. When it comes to agriculture, nutrient pollution is the result of fertilizer containing nitrogen or phosphorous being misapplied and washed out of fields into waterways. Excess nitrogen and phosphorus are also released from poorly managed and contained farm animal manure which can reach surface and groundwater through runoff and infiltration.

Scientists are studying the latest outbreak to better understand agriculture’s role, but food production systems have long been known to be a major factor. It’s also important to note that the polluted runoff — from sugar cane farms, cattle ranches and other farms — that continues to enter the region’s waterways every day is adding to the high nutrient load already present.

This is where it comes back to politics. Many are calling out the sugar industry for using its political power to avoid or delay cleaning up its own polluted runoff. The sugar industry has poured tens of millions of dollars into state and local races over the years — between 1994 and 2016, the industry made $57.8 million in direct and in-kind campaign contributions. Those contributions are coming under greater scrutiny in light of the severity of the current red tide and other blooms in the southern part of the Sunshine State. This year it appears that any connection to the sugar industry could potentially be a political liability.

Industrial agriculture has made Florida’s algal blooms worse, but this isn’t an isolated problem just for Floridians to face. A recent Environmental Working Group analysis shows that blooms have occurred in every state and that that the problem has “grown exponentially” since 2010. As long as industrial agriculture persists in using excessive amounts of fertilizer, runoff will be a continual problem.

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