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Algae Blooms



A phenomenon that occurs when due to human activities, a species has access to more nutrients than normal, causing a bloom in population. This leads to an imbalance in the ecosystem that is detrimental to other species.

The Algae Bloom, in particular, is one resulting from cultural eutrophication, where the two main contributors of minerals and nutrients into the water are raw sewage and agriculture. However, any usage including recreational use can contribute to this process and is one that has occurred historically. Eutrophication, most commonly the accumulation of phosphate and nitrate, occurs naturally and any human presence has meant the existence of cultural eutrophication. Say in the medieval era, the effects of this accumulation may have been no less than it is now, but a change did occur in that the effects are no longer localized and the Algae Blooms are being seen at a global scale. This is partially due to densification of population and industrial fertilizer use, however of note is the movement of nutrients in the form of food which also has a water amount attached in terms of production. Beyond the globalizing nature of agriculture, animal husbandry contributes to this process in the form of animal sewage along with any fertilizers used to produce any feed, most of which ends up in the water cycle.

As water tends to end up in the ocean, coastal and delta areas tend to be the most impacted by Algae Blooms, but areas with low water exchange like an Endorheic Basin are also particularly susceptible. Additionally, with the fracturing of the water cycle through dams, sewers, and globalized sources of phosphorus like the Kola Peninsula, the effects and contributions to Algae Blooms can reach far inland. However, cultural eutrophication in itself is a natural part of human existence and phenomenon such as the “Red Tide” are from extreme cases resulting from an incomplete biogeochemical water cycle.

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Seasonal bloom cycle of a cyanobacteria, Microcystis, that is prevalent in freshwater

Sources: Wilhelm, Steven W., George S. Bullerjahn, and R. Michael L. McKay. "The Complicated and Confusing Ecology of Microcystis Blooms." mBio 11.3 (2020): e00529-20. Web. 03 May. 2021.
  1. Wassmann, Paul. (2005). Cultural eutrophication: perspectives and prospects. Drainage Basin Inputs and Eutrophication: An Integrated Approach.