Nutrients are necessary for the survival of all living things. The phrase like ‘excess of anything is bad’ is very much justified here when the aquatic system has an overabundance of nutrients. Here, we are giving the concept, types, causes and preventive measures of Eutrophication for the aspirants who are preparing for the different competitive examinations.
The term 'Eutrophication' is derived from the Greek word 'eutrophos' which means nourished or enriched. In context with the environment, the Eutrophication can be defined as the addition of artificial or non-artificial substances such as nitrates and phosphate, through fertilizers or sewage, to a fresh water system. It leads to increase in the primary productivity of the water body or 'bloom' of phytoplankton.
There are two types of Eutrophication which are explained below:
1. Natural Eutrophication: In this eutrophication, water body like the lake is characterised by nutrient enrichment. During this process, oligotrophic lake is converted into a eutrophic lake. It permits the production of phytoplankton, algal blooms and aquatic vegetation that in turn provide ample food for herbivorous zooplankton and fish.
2. Cultural Eutrophication: It is caused by human activities because they are responsible for the addition of 80% nitrogen and 75% phosphorous in lake and stream.
1. Excessive use of fertilizers.
2. Concentrated animal feeding operations (CAFOs) are also a major source of polluting nutrients.
3. Industrial and domestic waste.
1. Algal blooms cover the water bodies like river, lake, stream or ocean, blocks light from reaching the water which prevents the aquatic plants from photosynthesizing.
2. Lack of photosynthesis causes oxygen deficiency which results in a decline of marine species.
3. Hypoxic condition forms the dead zones which have not only negative ecological impacts but also have economic issues.
4. The water can have a bad taste, colour and odour, which has a negative impact on tourism. Governments have to invest more in waste water treatment.
1. Industrial and domestic waste water must be treated before its discharge into water bodies.
2. Recycling of nutrients through harvesting.
3. Removal of algal blood.
4. Precipitants like alum, lime, iron and sodium aluminate may use. Physicochemical methods can be applied to remove nutrients. For Example- Phosphorous can be removed by precipitation and nitrogen by nitrification or denitrification.