From California to the Great Lakes and down to the Gulf of Mexico, the U.S. is being plagued by a rapidly growing and very toxic environmental hazard – Harmful Algal Blooms (HABs). In 2016 alone, over 20 states have had serious outbreaks. What causes these blooms and how can we prevent future occurrences?
HABs are commonly known as blue-green algae but they really aren’t algae at all. They are a primitive life form called cyanobacteria which are closely related to bacteria, but they photosynthesize like green algae. Cyanobacteria can occur as single cells, in colonies or in a filamentous state.
These cyanobacteria are very different than the more familiar green algae we often see in ponds, lakes and streams. Green algae are the “good guys” of the algal world. Being a primary producer, green algae is a food source for zooplankton, young frogs, fish and aquatic insects.
Cyanobacteria are the “bad boys” of the water world. They tend to grow in environments that are out of balance and are often associated with excessive nitrogen and phosphorous from fertilizer run-off. They kill with impunity, destroying aquatic life, pets, livestock and sickening humans.
Researchers and citizens across the country are concerned by the dramatic increase in the intensity and toxicity of HAB incidents over the last few years. Typical toxins in these blooms may include hepatotoxins (microcystins, cylindrospermopsins), neurotoxins (anatoxins, saxitoxins), dermatoxins (lipopolysaccharides, lyngbyatoxin) and others.
Recent events highlight the need for concern and more control. For example, in 2014 Toledo Ohio shut down water supplies for nearly half a million-people due to the most intense toxic algae bloom ever recorded in the Western Lake Erie Basin.
In a September 6, 2016 article on EcoWatch.com, algal blooms were reported in at least 30 California lakes and reservoirs. Bev Anderson, a scientist with the California Water Resources Control Board, expressed concern about the sheer number of outbreaks as well as the level of toxins they contained. She stated toxicity levels of “twenty micrograms per liter would cause concern, but these blooms are reporting readings as high as 15,000 micrograms per liter.”
In Florida, Gov. Rick Scott declared local states of emergency in St. Lucie, Martin, Palm Beach and Lee counties in June 2016, shutting-down beaches in south Florida which had been covered by toxic algae for months.
One of the largest areas of concern is the Gulf of Mexico. The National Oceanic and Atmospheric Administration (NOAA) website reported on August 2, 2017 that the “Gulf of Mexico “dead zone,” an area of low oxygen that can kill fish and marine life, is 8,776 square miles, an area about the size of New Jersey” – the largest measured reported “dead zone” in that area since mapping began in 1985.
NOAA acknowledges the dead zone is the result of excessive nutrients, “primarily from agriculture and developed land runoff in the Mississippi River watershed” that stimulates “massive algal growth”. When the algal growth decomposes, it robs oxygen from Gulf waters and causes loss of fish habitat. It also decreases reproduction in various fish species and reduces the average size of shrimp caught for market.
So, what can be done? Well for now, not much. Researchers have been working with farmers to change tillage patterns to prevent excess fertilizers from leaving crop land and entering waterways. They have also endorsed creating a buffer zone between farm land to help control run-off.
If effective, such measures would be a win-win for everyone and especially the environment. Farmers would rather keep fertilizers on their crops as opposed to having them flushed down a stream. Unfortunately, the results suggest these measures aren’t really having the intended effect.
To further complicate the excess nutrient problem, concentrated animal feeding operations (CAFOs) and other animal production facilities are not required to treat their animal waste before releasing it into the environment. Animal waste is high in nitrogen and often ends up in streams which eventually flow into larger waterways and initiate harmful blooms.
This is a significant problem when you consider 1 dairy cow produces the waste (total solids) equivalent of 50 humans every day and 1 feeder pig produces the waste (total solids) equivalent of almost 4 humans every day.
Currently, there are approximately 9.3 million dairy cows and almost 72 million hogs and pigs in the United States. That’s roughly the waste equivalent of 753 million people every day – more than double the 2017 population of the United States at 324.4 million! AND this figure doesn’t include beef cattle, poultry and other livestock.
Certainly, this whole situation is food for thought…
- “Algal Blooms Can be Deadly to Your Dogs”, EcoWatch – Top News of the Day, Website Post, July 28, 2017, Accessed December 9, 2017.
- D’Anglada, Lesley V., US EPA, “Editorial on the Special Issue – Harmful Algal Blooms (HABs) and Public Health: Progress and Current Challenges”, in Toxins 2015, 7, 4437-4441; doi:10.3390/toxins7114437, Website article, Accessed December 9, 2017.
- Fleming, Ron and Marcy Ford. “Human versus Animals – Comparison of Waste Properties”, Ridgetown College – University of Guelph, July 4, 2001. Website PDF article. Accessed December 11, 2017.
- Flesher, John and Angeliki Kastanis, “As algae worsens, farmers are asked to join anti-runoff effort”, AZCentral.com, November 23, 2017, as reported in The Arizona Republic, p. 36A.
- Gallagher, Shana. “Tyson Foods Linked to Largest Toxic Dead Zone in U.S. History”, AlterNet. Org, Reposted by Ecowatch, Web article, No date, Accessed October 31, 2017.
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- Scavia, Donald. “Nutrient pollution: Voluntary steps are failing to shrink algae blooms and dead zones”, University of Michigan, July 31, 2017. Website article. Accessed December 9, 2017.
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- Trevino-Garrison, Ingrid, et al.,Kansas Department of Health and Environment, “Human Illnesses and Animal Deaths Associated with Freshwater Harmful Algal Blooms—Kansas”, in Toxins 2015, 7, 353-366; doi:10.3390/toxins7020353, Website article, Accessed December 9, 2017.
- Turner, Eugene R and Nancy N. Rabalais, “2017 Forecast: Summer Hypoxic Zone Size Northern Gulf of Mexico”, Louisiana State University, Website PDF article. Accessed December 11, 2017.
- S. EPA Webinar. “An Overview of Harmful Algal Blooms (HABs) and Their Impacts in Freshwater and Marine Ecosystems – Part 1: Summer Webinar Series to Build Awareness About Harmful Algal Blooms and Nutrient Pollution”, Presented June 25, 2013, Various Speakers, Webinar PDF. Accessed December 11, 2017.
- “U.S dairy cow numbers up, but replacement heifer numbers lower”, Dairy Herd Management, Website article, July 29, 2014, Accessed December 11, 2017.
- “What are Blue-Green Algae (Cyanobacteria)? State of Washington, Department of Ecology. Website article. Accessed December 11, 2017.
- Wynne, Timothy T., et al. “NOAA Forecasts and Monitors Blooms of Toxic Cyanobacteria in Lake Erie”, Clear Waters Summer 2015, pp. 21-23, Website PDF article, Accessed July 28, 2017.