Does Eutrophication cause Algae Blooms?

blue-green algae

Eutrophication is the structural change of water ecosystems that is caused by excess nutrients. Eutrophication results in algal blooms and poor water quality.

In this article, we discuss what causes eutrophication, how it affects the environment, and how it is treated.

What Is Eutrophication?

Eutrophication is characterized by the increase of plant or algae due to an escalation of one or more growth factors necessary for photosynthesis: sunlight, carbon dioxide, and/or nutrients.

As the presence of nitrogen and phosphorus nutrients––also known as organic load––increase, it surpasses the capacity of the water to purify itself. An abundance of these nutrients––particularly phosphate––encourages quick growth of plants and algae. The rapid growth of algae is known as an algae bloom.

Slow eutrophication is a natural process that happens in all water bodies. The recent and continued occurrence of rapid eutrophication is an environmental issue that affects water quality.

What Causes Eutrophication?

Cultural practices and environmental factors cause eutrophication.

  • Sediment. Over time, water bodies accumulate silt and sediments that have absorbed large amounts of nutrients. As a water body fills with sediment, the interaction between the water and the sediment increases, mixing the nutrients with the water. This is a natural process that is hastened by erosion. Construction and demolition increase sediment and erosion.
  • Agriculture. Farmers use a high concentration of nitrogen and phosphate fertilizers, which contribute to rapid growth in plants. Rain and stormwater carry excess nutrients into groundwater and local water bodies. Erosion exacerbates the leaching of nutrients into water sources.
  • Wastewater. Human waste, household cleaning products, and soaps contain nitrogen and phosphorus. Nitrogen and phosphorus pollution can stem from the release of treated wastewater into local water bodies. Overflow events––caused by storms and flooding––sometimes wash these nutrients into water bodies in the form of raw sewage.

What Are the Consequences of Eutrophication?

With eutrophication, excessive nutrients encourage the rapid growth of algae and plants. The resulting increase in photosynthesis uses up dissolved inorganic carbon and increases pH to extreme alkaline levels. A highly alkaline pH impairs the chemosensory abilities of organisms that rely on chemical cues for their survival, essentially blinding them to predators.

Additionally, algae that grow uninhibited form a progressively large biomass that then dies off. When algae blooms die off, the microbial deterioration exhausts dissolved oxygen levels, creating hypoxic or anoxic conditions. As more and more algae grown, the lack of oxygen reduces biodiversity, causing plants and animals to die. This is compounded during the summer when oxygen concentrations are already low.

Algae blooms cause:

  • high pH
  • low oxygen
  • death of plants and animals
  • low light
  • blue-green algae

What Is Blue-Green Algae?

Blue-green algae, also known as cyanobacteria, thrive in the low light, anoxic conditions caused by algae blooms. Most blue-green algae blooms occur in ponds, lakes, and slow-moving streams during the summer months, when the water is warm. However, blue-green algae also grow in the sea. As its name suggests, blue-green algae are a blue-green color, but can also be red or brown. Blue-green algae are buoyant and forms floating mats that people mistakenly think of as pond scum. Because it can be suspended at different depths, blue-green algae may grow unnoticed until it rises to the surface where it seems to have appeared overnight.

Also known as harmful algal blooms (HABs), cyanobacteria produce toxins that are harmful to fish, animals, and humans. As blue-green algae die off, these toxins leak from deteriorating cells into the environment. There are many different species, and large blooms have the potential to produce several different toxins.

Blue-green algae can cause:

  • depleted oxygen levels
  • death of fish, wildlife, and livestock
  • dead zones in the water
  • eye and skin irritation, nausea, vomiting, and muscle cramps in humans
  • bad smelling water
  • bad tasting water
  • elevated water treatment costs

How Is Eutrophication Treated?

Treating surface water with herbicides can kill algal blooms. However, the resulting death of blue-green algae releases a large number of toxins into the surrounding water. It is critical to stop the phosphorus pollution at its source. This may mean spoon-feeding fertilizers, requiring silt curtains at construction sites, and growing native plants along shorelines to buffer runoff. Other controls for water affected by eutrophication include:

  • removal and treatment of water that is in contact with nutrient-rich sediment
  • removal of sediment
  • removal of phosphorus by the addition of iron or aluminum salts or calcium
  • removal of toxins from water through the use of chemicals
  • mechanical removal of the algae
    • addition of oxygen into the water
    • biological controls


Eutrophication resulting from nutrient-rich sediment, wastewater, and fertilizers causes algal blooms that are harmful to the environment and to humans. It’s critical to our global water quality that we stop the excessive nutrients from reaching water sources.

Have you experienced an algae bloom? How was it treated? What proactive steps were taken?

If you liked this blog article, be sure to stop back at a later date to read our next blog article about phosphate removal.

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Bargaining for Clean Water: Why Dean Kamen Invented the Coca-Cola Freestyle

The Coke Freestyle

The technology Kamen used to develop the Freestyle Coca-Cola soda fountain is similar to that in his prescription pumps.1

When Kamen asked Coke for help distributing his water purifier, Coke challenged Kamen to develop a better soda fountain first.

Dean Kamen, Inventor of Medical Technology

The inventor of the Segway, Dean Kamen is known in the scientific community for developing medical equipment. His inventions include a wearable prescription pump for insulin and chemotherapy, a microdosing prescription pump for infants, and a home dialysis machine.When Kamen realized his dialysis machine required too much distilled water and energy for home use, he developed a system to purify tap water that would run on less power than a hairdryer.

And that’s not all it does. Kamen’s water purifier can take any water source and return water safe even for infants to drink.2

How it works

  • Kamen’s water purifier uses vapor compression distillation system.
  • It uses less than one kilowatt of electricity per hour (less electricity than a hairdryer).
  • The purifier uses any water source, no matter how polluted—laundry water, groundwater, seawater, even sewage.
  • It boils and evaporates the source water then condenses and collects clean drinking water.
  • One system purifies up to 850 liters per day, which can provide safe drinking water for around 300 people.2, 3

Water Purification for the World

While he was developing it, Kamen realized his water purifier had world-wide benefits. It could supply clean water for disaster relief and to areas with polluted or low water supply.2

Waterborne Disease: #1 Killer

Kamen believes that 50% of the world’s medical issues can be solved with clean water. He says children are at the highest risk.4 The World Health Organization (WHO) agrees. Water-borne disease kills more than 3.4 million people, mostly children, every year, making it the world’s largest killer.5

This is the result of more than 2 billion people across the world using contaminated water. Approximately 844 million people lack a potable water source, including 159 million people who use surface water for their daily needs. WHO estimates that half the globe will be water-stressed by the year 2025.6

Goliath, Meet Slingshot

Kamen named his water purifier Slingshot as the appropriate weapon for the global water crisis, which he calls Goliath.4

Kamen’s goal to mass distribute Slingshots to thousands of water-polluted/water-stressed rural locations has been slowed by his lack of resources. Unfortunately, his medical connections were little help delivering water purifying systems to rural areas—medical technology is distributed in wealthy areas. So, he turned to Coke for assistance in mass distributing his invention.3

Bargaining: The Freestyle

Coke’s counter-proposal: first build a better soda fountain. This is how the inventor of medical supplies came to develop the Freestyle Coca-Cola soda fountain.2

Expanding the Handshake Deal

By the time Kamen’s soda fountain, the Coca-Cola Freestyle, was put in production, Coke had a new CEO. But Muhtar Kent didn’t drop Kamen’s handshake deal. He expanded on the informal agreement to mass-produce and distribute the water purifier. To get the water purifiers to rural areas, Coke is distributing Slingshots within their Ekocenter.2

Ekocenter Modular Community Market

Coke’s Ekocenter is a solar-powered shipping container that provides low-income rural communities with safe water, internet access, non-perishables, first-aid supplies, and more. Coca-Cola calls their Ekocenter a “modular community market.” It is an opportunity for local (usually female) entrepreneurs, who are trained by Coke.6

Going Far Together

To distribute the Ekocenters, Coke is following the proverb, “If you want to go fast, go alone. If you want to go far, go together.” Coke has pooled resources with 10 other companies to greater impact the world. By December 2017, 150 solar powered Ekocenters had been placed in 8 low-income countries. These Ekocenters can distribute 78.1 million total liters of potable drinking water per year.6

Kamen’s Vision and Future Use

Kamen’s vision involves the distribution of 2,000 units to low-income rural areas.2 Is his vision of clean water distribution different than Coke’s vision? Is the need more immediate? In America, water-polluted urban areas like Reno and Las Vegas; Pittsburg; Milwaukee; Flint, Michigan; Brady, Texas; to name a few, and the water-stressed state of California, which is researching ways to recycle wastewater for potable use, might look into using the Slingshot. Comment below and let us know what future use(s) you envision for Kamen’s Slingshot.

Tune in next week to read Toilet-to-Tap—Taking the Ick Out of Wastewater Recycling.

  1. Coca-Cola Freestyle: The Soda Machine of the Future (+ the Past), By Elina Shatkin, March 1, 2012.
  2. Popular Science, Pure Genius: How Dean Kamen’s Invention Could Bring Clean Water to Millions, by Tom Foster, June 16, 2014.
  3. Coca-Cola Journey™: Sustainability, EKOCENTER & Slingshot Clean Water Partnerships.
  4. WHO Drinking-water Key Facts, February 7, 2018,
  5. Dean Kamen Inventor – Slingshot Water Purifier, By Datun Center, April 17, 2015.
  6. WHO: Waterborne Disease is World’s Leading Killer, by Jessica Berman, October 29, 2009.
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