Uncovering Algal Blooms

Uncovering Algal Blooms
Let’s start with defining “Harmful Algal Blooms” (HABs)…

Simply stated, HABs are overgrowths of algae in the water. Depending on the type of algae, some produce dangerous toxins in fresh or marine water. However, even if the algae is nontoxic, it can still negatively impact the environment and the local economies that rely on the waters for vital reasons such as water supplies, wildlife, and tourism.

When did Harmful Algal Blooms (HABs) come into existence?

This is one of the most important facts to consider regarding the “breaking news” publications within our times – HABs in the Gulf of Mexico have been occurring dating back to the 1500s when explorers, such as Cabeza de Vaca, set out to explore the unknown territory, “La Florida”, a.k.a. present-day Florida. (2)

In California, a type of algae known as Lingulodinium polyedrum, best represented by its bioluminescence, has regularly been recorded in the warm coastal waters since 1901. The glowing is actually caused by a massive red tide, or algae bloom, of bioluminescent phytoplankton. (8)

So, at this point, you may be thinking, do notable long-dated occurrences of algae blooms just occur in the United States?

No, actually one of the largest algal blooms on record occurred in 1991 over the Barwon and Darling Rivers in New South Wales, Australia. (3)

So, what causes harmful algal blooms?

Long existing research has discovered that generally speaking, the occurrence of HABs is a routine part of nature. There are two main nutrients that directly impact HABs: phosphorus and nitrogen. (7)

Studies show that many algal species flourish when wind and water currents are favorable, which explains why HABs are native to certain areas.

Natural phenomena like sluggish water circulation, unusually high water temperatures, and extreme weather events like hurricanes, floods, and droughts are also contributed to the cause of HABs. (7)

While HABs may normally exist in the environment, there are occurrences where nutrients known to feed the algae blooms build up at an excessive rate which leads to an “overfeeding.” This is caused by a variety of factors derived from anthropogenic climate change. Likewise, anthropogenic climate change can also cause HABs to appear in never before documented areas.

A boat cuts a green wake—a harmful algal bloom—in Western Lake Erie.
Reference: US Department of Commerce, & National Oceanic and Atmospheric Administration. (2013, June 01). How do we forecast harmful algal blooms? Retrieved from https://oceanservice.noaa.gov/facts/hab-forecast.html

So, what human activities are we engaging in that could unnaturally contribute to HABs?

First and foremost, we can all agree that the population has increased over the years. Take a look around… how many new home communities, new schools, new commercial construction projects, etc. have you seen over the last 5-10 years?

To bring the statistics to the table, there were 13,223,000 new houses sold in the United States from 1995 to 2017. Clearly, with these numbers, we can all agree that there is inevitably less undeveloped land available. This results in more people residing in concentrated areas than there was in prior times. (9)

Less undeveloped land and more people means increased sewage, trash, landscaping to manage, the need for more food, and more overall pollution in a given area. Undoubtedly, this truth alone plays a major role in our environment, not only in regards to HABs. Moreover, it is important to understand that this is a worldwide issue, not just one of the United States.

Let’s get scientific…

To correlate the above to a scientific stance, it is known that algal blooms are naturally influenced by a combination of environmental factors including available nutrients, temperature, sunlight, ecosystem disturbance, hydrology (river flow and water storage levels), and water chemistry. (7)

Each of these scientific factors can also be altered by unnatural forces; leading to why anthropogenic climate change is contributing to HABs either being overfed or to develop in atypical areas.

a. Available Nutrients:

Naturally Occurring: The internal origin of nutrients comes from the lake/reservoir sediments. Phosphate attaches to sediments. When dissolved oxygen concentration is low in the water (anoxic), sediments release phosphate into the water column. This natural phenomenon encourages the growth of algae. (7)

Unnaturally Occurring: Anthropogenic climate change impacts the available nutrients by either depletion or by excess. Specific events contributing to this include excessive erosion, land-clearing, and sewage which are known to release phosphorous and nitrogen into the waterways.

b. Temperature:

Naturally Occurring: Early blue-green algal blooms usually develop during the spring when water temperature is higher, and there is increased light. The growth is sustained during the warmer months of the year when water temperatures are above 77°F, which is considered to be the optimal time for the growth of Cyanobacteria. At these temperatures, blue-green algae also have a competitive advantage over other types of algae that typically prefer lower temperatures. (7)

Unnaturally Occurring: Multiple studies confirm that warmer than normal water temperatures, or warmer waters during atypical months can be caused by anthropogenic climate change for a number of reasons such as emissions, gases, etc.

c. Ecosystem Disturbance:

Naturally Occurring: Natural disasters such as hurricanes, tsunamis, and droughts.

Unnatural Occurring: Over consumption of water caused by human and animal consumption, irrigation, and the regulation of waters by weirs and dams can lead to a disturbed ecosystem causing pH changes, vertical mining, and trace metals within waterways. Likewise, food web alterations and newly introduced species throw off the natural cycles within the ecosystem which leads to a multitude of environmental concerns. A specific food web alteration that impacts algae blooms is when oysters and other filter feeders (which are responsible for consuming phytoplankton within the waters) are removed either for consumption or redirection of the waterway. Without enough oysters, there is unconsumed phytoplankton which sinks to the bottom of the waters to be decomposed by bacteria. The process of their decomposition, in turn, depletes the water of oxygen – yielding a prime environment for algae blooms.

d. Sunlight:

Naturally Occurring: Blue-green algae flourishes in light fluctuating environments such as a very sunny morning and a cloudy and rainy afternoon. This intermittent light exposure is also particularly favorable to cyanobacteria because it has the unique ability to adapt to varying light conditions.

Unnaturally Occurring: Anthropogenic climate change is related to light availability as a result of the construction of buildings, bridges, and other human-made structures which causes artificial lighting over bodies of water.

e. Hydrology:

Naturally Occurring: High discharge after a rain event.

Unnaturally Occurring: The alteration of natural water flows, the creation of stagnant waters, the intensifying of coastal upwelling, and sea-level changes resulting from anthropogenic climate change – are all factors that can be caused from the building of roads, homes, land clearing, humanmade ponds, and lakes, etc.


Reference: Toxic Algae Found in Two Central Park Waterways. (2018, June 15). Retrieved from https://barleyprize.org/blog/2018/06/14/toxic-algae-found-two-central-park-waterways/

Where do HABs naturally occur?

As far as the United States, every U.S. coastal and Great Lakes state experiences HABs.

In the southern and tropical climates where water temperatures are often warmer, there is a greater chance for naturally occurring HABs. However, places such as Lake Erie, Puget Sound, Chesapeake Bay, and the Gulf of Maine also experience regularly occurring HABs. (12)

While HABs occur across the world, there are different types of algae blooms known to present themselves in specific areas. For example, in the Gulf of Mexico along the Texas coast, the most frequent algae type is known as Karenia Brevis, and in Florida, home to one of the largest bodies of freshwater, Lake Okeechobee, the toxic cyanobacteria, also known as blue-green algae, is the most prevalent type of algae. (12)

Satellite imagery of Sept. 2017 algae bloom in Lake Erie/NASA
Reference: Grzegorek, V. (2018, July 22). Scientists Say Lake Erie Toxic Algae Blooms Could Be Part of Climate Change Loop. Retrieved from https://www.clevescene.com/scene-and-heard/archives/2018/05/16/scientists-say-lake-erie-toxic-algae-blooms-could-be-part-of-climate-change-loop


What is the solution?

There is no one solution to handle overfed algae blooms because there is no one specific condition or cause that influences HABs growth.

While HABs cannot be prevented, we can be better prepared. (12)

Undeniably, careful zoning, planning, and natural waterway restoration efforts are vital. Likewise, intentional environmental conservation efforts, more conservative shellfish and animal protection laws, reducing pollution, limiting the use of harsh chemicals, and stricter industrial eco-friendly requirements will help to keep algae blooms under control.

What’s being done?

The National Oceanic and Atmospheric Administration, NOAA, is an organization that is on the forefront of HAB research. Their goals are to better understand how and why these blooms form, improve detection, and provide forecasting for these seasonal events to be able to issue communities with advance warnings to adequately plan for and deal with the adverse environmental, economic, and health effects associated with HABs. (12)

In 2015, NOAA joined forces with NASA, the U.S. Environmental Protection Agency and U.S. Geological Survey to transform satellite data designed to probe ocean biology into information that will help protect the American public from harmful freshwater algal blooms. The effort is designed to be an early warning system for toxic and nuisance algal blooms in freshwater systems by using satellites that can gather color data from freshwater bodies during scans of the Earth. Based on this information, state and local agencies can provide the public with public health advisories. In addition, the project will improve the understanding of the environmental causes and health effects of these cyanobacteria and phytoplankton blooms in the United States. (12)

Algae covered water at Stuart’s Central Marine boat docks is thick on June 30, 2016, in Stuart, Florida.

So, what’s the deal in South Florida?

Specifically addressing solutions to our local areas, we have to acknowledge that we have problems that relate to algae blooms, which equally and correspondingly need solutions – flooding, water flow, and overdevelopment of land.

Let’s talk about flooding…

Dr. Diane Mas, REHS/RS, an associate at a civil and environmental engineering consulting firm Fuss and O’Neill, said in a recent statement, “The current conditions at Lake Okeechobee highlight the challenge of balancing the multiple threats to the public – those associated with floodwaters around the lake that are prompting water to be released and those associated with possible downstream exposure to algal toxins in the released water containing cyanobacteria.” (13)

So what do you do? Well, the U.S. Army Corps of Engineers briefly suspended water releases from Lake Okeechobee to Caloosahatchee and St. Lucie estuaries until they announced their plan for a 14-day pulse release schedule of water releases from the lake, which began on July 13 as the lake’s water levels approach 14.5 feet. (13)

The U.S. Army Corps of Engineers said that its flood-risk-management decision is based on the fact that a major breach of the 143-mile Herbert Hoover Dike surrounding Lake Okeechobee would threaten 37,000 people living nearby, potentially damaging homes, businesses, structures and roads, and proving costly to remove water from flooded areas. (13)

So, what’s the problem with the water flow?

This problem initiated in 1915 with the construction of the road that was built through the heart of the Everglades – U.S. Highway 41 a.k.a. the Tamiami Trail. Nearly 13 years and 3 million sticks of dynamite later, this main thoroughfare connecting Tampa to Miami was completed, but its major effects on the ecosystem were just beginning. (1)

Although it was built as a road, it soon became apparent that the Tamiami Trail was also a dam, blocking water that flowed from Lake Okeechobee south through the Everglades to Florida Bay. This caused areas of Everglades National Park that used to be wet year-round to dry out for months at a time – resulting in the disappearing of peat soils, vegetation, and the altering of the food chain for small fish and macro-invertebrates. (1)

Discovering the significant problem this created, an 18 billion dollar “Comprehensive Everglades Restoration Plan” was put into action; yet, it will never to able to fix what was lost and altered. The plan is designed to help restore the ecosystem that is covering 1.5 million acres, but the Everglades once covered more than double that area. Furthermore, it will be a human-made, engineered solution with pumps and reservoirs. (1)

Dawn Shirreffs, a representative with the Everglades Foundation, stated, “We’ve lost about half of the natural ecosystem. We’ll never get that half back. It’s developed; most of us are living on land that was formerly Everglades. But we can stop hemorrhaging the existing Everglades.” (1)

The plan is set to be completed around 2030, and in combination with the “Central Everglades Planning Project,” it has been said that we could begin delivering a lot more water back to the area by 2020. (1)

Overdevelopment of Land…

This is a given, we see it with our own eyes, but to leave you with some food for thought…

Recently a longstanding member of the Palm Beach County Planning Commission, Domenic R. Guarnagia, resigned shortly before the Planning Commission decided on the controversial development proposal from South Florida home builder GL Homes.

GL Homes was proposing that the county change the rules of its Agricultural Reserve so that they would be able to build more on land the developer owns within the reserve. (11)

In his resignation letter, dated October 3, 2017, Guarnagia specifically mentions GL Homes, saying the developer’s “interest is in building in spite of corrupting acres of productive farmland and greatly reducing the acreage of land that could otherwise benefit us all.” Furthermore, he also said preserving the Agricultural Reserve as a large mass of arable land is critical for two reasons: the large percentage of winter vegetables that it produces for the U.S. and its role in absorbing huge amounts of rainfall through percolation. He also noted that he was especially frustrated when the County Commission decided to approve development projects that both the zoning staff and a majority of the Planning Commission had recommended denying. (11)

The Conclusion

Although algae blooms have been around for centuries, our awareness of them is more prevalent than ever before. First, we have a demand for the usage of multiple bodies of water for consumption, tourism, and filtration; meaning more people come in contact with and/or use bodies of water for various uses than ever before. Second, we have the media to inform us of the seasonal presence of HABs. Third, we have technology and researchers to discover, learn, and study the algae and share their findings with us which we would have otherwise never known.

We also now understand that algae blooms are not unnatural and randomly appearing; they are part of nature. Overfed algae blooms are the problem, and while no one can go back in time to undo the things that have caused us to experience the recent increase in HABs, we can work together to make a difference for our future.

The bottom line is this…

if we want to improve the quality of our waters, it is up to each of us as individuals, organizations, and governments to work together to be the solution. We need to take care of the lands that yield our food, balance our ecosystem, and ultimately provide us with life.


  1. Allen, G. (2016, February 19). Once Parched, Florida’s Everglades Finds Its Flow Again. Retrieved from https://www.npr.org/2016/02/19/466582238/once-parched-floridas-everglades-finds-its-flow-again
  2. “Alvar Nunez Cabeza De Vaca.” (Web. 5 Dec. 2014. ) The Mariners’ Museum | EXPLORATION through the AGES. Retrieved from http://ageofex.marinersmuseum.org/index.php?type=explorer&id=67 / https://ipfs.io/ipfs/QmXoypizjW3WknFiJnKLwHCnL72vedxjQkDDP1mXWo6uco/wiki/Cabeza_de_Vaca.html
  3. Bowling, L.C. and Baker, P.D; ‘Major Cyanobacterial Bloom in the Barwon-Darling River, Australia, in 1991, and Underlying Limnological Conditions’; Marine and Freshwater Research, 47 (1996); pp. 643-57
  4. EPA. (2017, December 12). Causes and Prevention. Retrieved from https://www.epa.gov/nutrient-policy-data/causes-and-prevention
  5. EPA. (2018, July 19). Harmful Algal Blooms. Retrieved from https://www.epa.gov/nutrientpollution/harmful-algal-blooms
  6. Lam, C. W. Y.; Ho, K. C. (1989). “Red tides in Tolo Harbor, Hong Kong”. In Okaichi, T.; Anderson, D. M.; Nemoto, T. Red tides. biology, environmental science and toxicology. New York: Elsevier. pp. 49–52. ISBN 0-444-01343-1.
  7. Purdue University. (n.d.). Indiana University–Purdue University Indianapolis. Retrieved from https://cees.iupui.edu/research/algal-toxicology/bloomfactors
  8. Nelson, B. (2017, May 31). What is causing the waves in California to glow? Retrieved from https://www.mnn.com/earth-matters/wilderness-resources/stories/what-is-causing-the-waves-in-california-to-glow
  9. Statista. (2018). Number of new houses sold in the U.S. 1995-2017 | Statistic. Retrieved from https://www.statista.com/statistics/219963/number-of-us-house-sales/
  10. A. P. (2017, September 01). The ABCs of HABs: How Harmful Algal Blooms Impact the Bay. Retrieved from https://www.chesapeakebay.net/news/blog/the_abcs_of_habs_how_harmful_algal_blooms_impact_the_bay
  11. Washington, W. (2017, October 20). Planning commissioner quits, citing GL Homes plan, other development. Retrieved from https://www.palmbeachpost.com/news/local-govt–politics/planning-commissioner-quits-citing-homes-plan-other-development/9TTN79ZrPupIvlzXmci6uI/
  12. What is a harmful algal bloom? | National Oceanic and Atmospheric Administration. (n.d.). Retrieved from http://www.noaa.gov/what-is-harmful-algal-bloom
  13. Williams, A. (18, July 13). Toxic blue-green algae plagues South Florida’s waterways; Governor declares state of emergency. Retrieved from https://www.accuweather.com/en/weather-news/toxic-blue-green-algae-plagues-south-floridas-waterways-governor-declares-state-of-emergency/70005487


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