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  • Writer's pictureHydroPhos Team

2023 Eutrophication Recap

Eutrophication is an ecological phenomenon found throughout the world that occurs when bodies of water have an excess amount of certain nutrients, typically phosphorus or nitrogen. The excess nutrients cause rapid growth of algae and aquatic plants. When the algae decomposes, oxygen levels in the water are depleted, leading to the formation of "dead zones" where aquatic life struggles to survive. This process fundamentally alters the balance of aquatic ecosystems and decreases water quality. Our recap aims to overview of some of the largest occurrences of eutrophication that happened in the United States throughout 2023.

Southern California Sea 

In June, hundreds of sea lions and nearly 60 dolphins were killed off the coast of Southern California due to the growth of harmful algae in the water. Between June 8th and June 14th, over 1,000 sick or dead marine mammals were reported to the Channel Islands Marine and Wildlife Institute, an organization that responds to live marine mammal strandings. The species of algae that grew in the water is Psuedo-nitzschia, which produces a neurotoxin, domoic acid, that works its way up the food chain. Domoic acid accumulates in small fish, so seabirds and marine mammals (including dolphins and sea lions) amass the toxin in their body when they eat fish containing domoic acid. The neurotoxin causes many symptoms in marine mammals including swaying, paralysis, involuntary muscle spasms and seizures. These symptoms often cause the animals to become stranded. In humans, the neurotoxin can cause brain damage and seizures. Luckily, domoic acid does not affect humans unless it is consumed in food items that contain the toxin.                     


Map showing the estimated amount of Domoic Acid in the water off the coast of California


Lake Okeechobee (Florida)

Lake Okeechobee is the largest freshwater lake in Florida. The lake covers 730 square miles, and is over half the size of Rhode Island.  While the lake encompasses a large surface area, Lake Okeechobee is fairly shallow with an average depth of only nine feet. This lack of depth makes Lake Okeechobee extra susceptible to eutrophication. This year, approximately half of the lake was covered in algae for most of June and July. By the second week of July, an estimated 440 square miles of the lake were covered in algae. This is the equivalent of over 19 Manhattans covered in algae. The algae bloom caused several counties to release public health warnings, and residents were warned to not swim or boat in the lake due to potential exposures to toxins created by the algae. Part of the Pahokee City Marina was also closed due to the algae bloom.

Algae bloom in Lake Okeechobee, seen from the Pahokee City Marina


Red Tide Texas 

Red Tide is a type of algae bloom that occurs in coastal waters. The high concentrations of algae growing in the water causes the water to become discolored, often turning a reddish color.  Red tides remove oxygen from the water, killing fish and other aquatic species. The algae in red tides can also release toxins that cause illnesses in humans and other animals. In September 2023, red tide was detected off the coast of Texas for the first time since 2018. The type of algae in this particular red tide, Karenia brevis, creates a toxin that affects the central nervous system of fish, preventing them from breathing properly. Dead sharks and several species of fish linked to the red tide were found washing up on shores in several areas. 

When waves crash onto the shoreline, some of the algae from the red tide is sprayed into the air. This can cause respiratory and sinus irritation in humans and the symptoms are often worse for those with asthma. Several people reported respiratory irritation, coughing and other symptoms after spending time by the shoreline where the red tide was in Texas.


An image of the red tide off the coast of Texas


Western Lake Erie

Lake Erie typically has issues with algae blooms on an annual basis. Algae blooms usually start in August but this year they started in the beginning of July, a month earlier than usual. The blooms started on the western side of the lake, near Toledo. The type of algae that grew in Lake Erie is called cyanobacteria and is a greenish color. Cyanobacteria blooms release a toxin that is harmful to the liver, which poses a risk to humans and other animals that enter the water. The algae blooms in Lake Erie are typically caused from runoff that contains phosphorus from nearby agricultural areas. Each year, the algae blooms in Lake Erie are indexed using satellite imagery to assess the biomass of the algae bloom. The 2023 bloom was considered moderately severe based on the severity index rating.

A satellite image showing the 2011 algae bloom in Lake Erie

Eutrophication is a growing problem throughout the United States and it can have devastating effects on aquatic ecosystems and local economies. Algae blooms pose risks for aquatic species and humans. By finding ways to reduce the levels of phosphorus and nitrogen in the water, the number of algae blooms that occur will decrease and the ones that do occur will be less severe. HydroPhos Solutions is developing filters to remove phosphorus from wastewater, to help reduce the amount of phosphorus entering bodies of water and preventing eutrophication.


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