What is eutrophication?
Eutrophication process multiplies the amount of algae in lakes and dams, bringing environmental problems
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Do you know what eutrophication is? It is a process of algae multiplication, common in bodies of water without much movement, such as lakes and dams. Although it means a large amount of organic matter present in water, it can bring many harms to humans and nature itself. But why?
The wide availability of nitrogen (N) and phosphorus (P) in the water of lakes, dams or ponds provides a totally favorable environment for the large and rapid multiplication of algae. When the level of eutrophication of water increases from time to time (over wide time intervals), it is considered a natural process. But when eutrophication takes place in a short period, scientists consider it to be an anthropogenic cause, that is, caused by human influence.
Where does eutrophication come from?
NASA edited and resized image is in the public domain
The supply of nitrogen and phosphorus in water occurs in different ways, as described in this study. When caused by humans, it can originate from domestic sewage, where these nutrients are found in feces, urine, food waste and detergents. Certain shampoos that contain sodium lauryl ether sulfate or sodium lauryl sulfate can also contribute to eutrophication because they contain sulfate in their composition.
The nutrients that, in excess, cause eutrophication can also come from untreated industrial effluents. In plantations, the pesticides used are rich in nitrogen and phosphorus and provide more nutrients than the plants can absorb - their excess ends up being carried to the nearest water body, through irrigation water runoff or groundwater contamination . Livestock also contributes to the discharge of water contaminated with animal feces and urine and other waste.
Consequences
The huge population of algae resulting from eutrophication creates a green curtain on the surface of the water body, blocking the passage of light. Thus, the plants that stay at the bottom cannot carry out photosynthesis and the level of dissolved oxygen becomes smaller and smaller, causing the death of many organisms, such as fish, for example. The decomposition process of organisms also uses oxygen. Then, when this amount of dissolved oxygen can no longer be measured, the lake or pond is considered to have reached the state of anoxia.
In addition to the decrease in the number and biodiversity of organisms, excessive eutrophication is also responsible for the reduction of transparency, change in the color and odor of water, production of bad smell, toxic substances by some algae and inability to use water for purposes of consumption, recreation, tourism, landscaping, irrigation and hydroelectric power.
Control of eutrophication
To control eutrophication, preventive or corrective techniques can be used. Preventive measures are based on reducing the supply of harmful nutrients to the lake from an external source, controlling urban sewage, treating industrial effluents and reducing the use of pesticides. Correctives, on the other hand, act on the body of water already eutrophic, such as the use of reagents to reduce the availability of phosphorus and harvest algae from the surface.
In order not to contribute to the eutrophication of lakes and ponds, eat organic food, which is not grown with fertilizers, which is also healthier. Pay attention to the types of cleaning materials you use in your home, avoiding detergents and preferring biodegradable products. Also worry about whether the sewage in your neighborhood or city is treated and, if not, claim this measure to the government.
