In details


Green water of a lake: eutrophication

Introduction (what it is)

We like to walk on the edge of a lake. Over time we noticed an unpleasant smell coming from him. It's just that a process called eutrophication is taking place there.

A terrestrial or aquatic environment that goes through this is becoming eutrophic. The word trophía can be translated from Greek to Portuguese as a nutritional condition. In the case of a eutrophic lake, its nutritional condition is: complete, above desirable.

The excess nutrients did not end up in the lake without reason. Well-preserved lakes are oligotrophic, meaning they have few nutrients.

Main features

In any ecosystem, if nutrients are made available in small doses (which occurs naturally through slow decomposition of matter), population size remains stable.

But when nutrient intake is very high, populations tend to grow. The producing organisms in the food chain that surrounds the lake and its surroundings are: bacteria, algae and plants such as water hyacinths and grasses. If millions of nutrient particles dissolved in water are offered, the production of organic matter by these organisms will increase.

Populations increase rapidly. More individuals are born and more individuals die. The burden of dead individuals represents more organic matter in water. Therefore, a process of eutrophication feeds itself.

A eutrophic lake usually has turbid water, indicative of high biological productivity. It also exudes bad smell, which is produced by a surplus of decomposing bacteria. They take advantage of the fact that there is too much organic matter to degrade. At the same time, the activities of these bacteria decrease the oxygen content of water. Then the fish suffocate and eventually die.

The origin of eutrophication

Human activities generate chemical compounds. Many of these are dumped into lakes through domestic sewage, for example. Other times, rainwater transports portions of fertilizer (phosphates, nitrates) from higher ground into the lake. Generally the fields of human cultivation are on these grounds.

Ecological curiosity:

Ecology research allows one to assess whether a lake is less or more vulnerable to eutrophication. It is currently possible to develop and apply genetically modified organisms. They metabolize some fertilizers, making them harmless byproducts.