Algal bloom

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Algal blooms form due to a sudden increase in the amount of algae in water. Some algal blooms occur naturally and others may form from outside factors [1]. While some algal blooms are harmless other blooms can be harmful and have an impact on the environment and humans.


Algal bloom at Homebush Bay; Photo credit Ian Sanderson
Lake Erie affected by Algal blooms in October of 2011; from NASA

Many variables can change how a bloom is created, the duration and the intensity of a bloom. Changes in the methods and amounts of agricultural fertilizer can also create algal blooms [2].Changes in agricultural practices and and increase in heavy rain fall are believed to be large contributors to algal blooms [2]. Phosphorus from fertilizers is the primary component that can cause harmful algal blooms that are toxic [2].

Other variables that can contribute to algal blooms include, temperature, nutrient pollution, water flow and others [3].


Preventative measures help manage the creation and spread of algal blooms. One of the main prevention methods is to control the amount of excess nutrients in water [3]. Other practices include managing water treatment discharges, agricultural runoffs, and stormwater runoffs [3]. Other methods include mixing water through air bubbles or any other methods to increase water flow. However these practices can be expensive.

Possible agricultural changes include a switch to more fall fertilizer applications instead of spring applications,using broadcast fertilizer applications that do not incorporate fertilizer into the soil, lastly,an increase in no-till field management that leads to a build-up of phosphorus in the top layers of soil [2].


Impacts of algal blooms are not limited to just the water. Impacts from algal blooms include economy, tourism, property values, commercial fishing [4]. Algal blooms in bodies of water used for drinking water can drive up the cost of the drinking water due to treatment costs. Tourism loses close to $1 billion each year because of water affected with algal blooms [4].

Impacts on humans

Humans can be impacted by an algal bloom through the water, plant and animal life around a body of water that contains an algal bloom. Humans may ingest the toxins from an algal bloom through drinking water, water activities, or consuming plant life contaminated by an algal bloom [5].

Ingestion of an algal bloom or any plant life contaminated, the symptoms reported include abdominal pain, nausea, vomiting, diarrhea, sore throat, and dry cough, headache, blistering of the mouth, atypical pneumonia and elevated liver enzymes in the serum [5].

See also

Other closely related articles in this wiki include:


  1. St. John River Water Management District. (June 2014).Understanding Algal Blooms. October 30.
  2. 2.0 2.1 2.2 2.3 Kozacek, Codi. (April 2014).Cause of Lake Erie’s Harmful Algal Blooms Gains More Certainty, September 16.
  3. 3.0 3.1 3.2 United States Environmental Protection Agency. (June 2015). Nutrient Policy and Data, September 23.
  4. 4.0 4.1 United States Environmental Protection Agency. (October 2015). The Effects:Economy, October 9.
  5. 5.0 5.1 Wayne, W . (2013, November 23). Human Health Effects from Harmful Algal Blooms: a Synthesis, October 9.

External links