Eutrophication is a term used to describe the process by which a body of water becomes overly rich in nutrients (typically phosphorus and nitrogen).
This overabundance of nutrients is caused by precipitation carrying these nutrient compounds from land to waterways in the form of runoff.
These nutrient rich conditions trigger the rapid growth of algae blooms that happily feed on the increased resources. Growing, spreading, and turning the water green.
These algae blooms form a thick layer of organic matter across the water’s surface. Blocking out the sun.
Aquatic plants that require photosynthesis to survive, die without sunlight. Like all living things, eventually, the algae dies too.
The decaying plant and algae matter settles to the bottom of the body of water. Where it is broken down by bacteria, which consume oxygen in the water as part of the process and release toxic compounds such as ammonia as a by-product.
These water bodies with decreased oxygen levels, called “hypoxic” or “dead” zones, are no longer capable of supporting life on a large scale.
Fish, crustaceans, and mollusks in these areas either die or, if they are mobile such as fish, leave the area.
Habitats that would normally be teeming with life become, essentially, biological deserts.
The process of eutrophication is exacerbated by human activities such as the overuse of fertilizers and the discharge of wastewater into waterways.
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