Essay Example on Eutrophication is considered as one major aspect of global environment Degradation

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Introduction Eutrophication is commonly considered as one major aspect of global environment degradation Nixon 1995 Eutrophication is today both in the developed and in the developing world one of our most pressing environmental problems In recent years in one form or another it has received considerable media attention mainly because of the increasingly pressing need to maintain supplies of fresh water However amongst natural scientists in general and therefore amongst the environmental managers that many of their students nowadays become appreciation of the theoretical basis of scientific understanding of the nature and causes of eutrophication as a process and therefore of its ultimate solutions as a practical problem is poor and based on many misconceptions Eutrophication which comes from the Greek eutrophos well nourished has become a major environmental problem Nitrates and phosphates especially from lawn fertilizers run off the land into rivers and lakes promoting the growth of algae and other plant life which take oxygen from the water causing the death of fish and mollusks Cow manure agriculture fertilizer detergents and human waste are often to blame as well In the 1960s and 70s the eutrophication of Lake Erie advanced so extremely that it became known as the dead lake And many areas of the oceans worldwide some more than 20 000 square miles in extent have become dead zones where almost no life of any kind exists 1 2 What is eutrophication Eutrophication is an enrichment of water by nutrient salts that causes structural changes to the ecosystem such as increased production of algae and aquatic plants depletion of fish species general deterioration of water quality and other effects that reduce and preclude use 



This is one of the first definitions given to the eutrophic process by the OECD Organization for Economic Cooperation and Development in the 70s Eutrophication is a serious environmental problem since it results in a deterioration of water quality and is one of the major impediments to achieving the quality objectives established by the Water Framework Directive 2000 60 EC at the European level According to the Survey of the State of the World's Lakes a project promoted by the International Lake Environment Committee eutrophication affects 54 of Asian lakes 53 of those in Europe 48 of those in North America 41 of those in South America and 28 of those in Africa All water bodies are subject to a natural and slow eutrophication process which in recent decades has undergone a very rapid progression due to the presence of man and his activities so called cultural eutrophication The cultural eutrophication process consists of a continuous increase in the contribution of nutrients nutrients mainly nitrogen and phosphorus organic load until it exceeds the capacity of the water body i e the capacity of a lake river or sea to purify itself triggering structural changes in the waters 1 3 Types of eutrophication Eutrophication is mainly of two types 1 Natural Eutrophication and 2 Cultural Eutrophication 1 Natural Eutrophication The process of lake aging characterized by nutrient enrichment is called natural eutrophication During this process oligotrophic lake is converted into an eutrophic lake It permits the production of phytoplankton algal blooms and aquatic vegetation including water hyacinth aquatic weeds water fern and water lettuce which in turn provide ample food for herbivorous zooplankton and fish 2 Cultural Eutrophication This process is generally speeded up by human activities which are responsible for the addition of 80 nitrogen and 75 phosphorus to lakes and streams Lake Mendota and Lake Washington have undergone rapid eutrophication due to man s activities is possible 1 4 Common Causes of Eutrophication

The first factor of eutrophication is using of fertilizers Agricultural practices and the use of fertilizers in the soil contribute to the accumulation of nutrients When these nutrients reach high concentration levels and the ground is no longer able to assimilate them they are carried by rain into rivers and groundwater that flow into lakes or seas The example refers to appendix 1 4 A Secondly discharge of waste water into water bodies also cause eutrophication Refer to appendix 1 4 B In various parts of the world and particularly in developing countries wastewater is discharged directly into water bodies such as rivers lakes and seas The results of this is the release of a high quantity of nutrients which stimulates the disproportionate growth of algae In industrialized countries on the other hand waste water can be illegally discharged directly into water bodies When instead water is treated by means of water treatment plants before discharge into the environment the treatments applied are not always such as to reduce the organic load with the consequent accumulation of nutrients in the ecosystems The another cause of eutrophication is reduction of self purification capacity Refer to appendix 1 4 C Over the years lakes accumulate large quantities of solid material transported by the water sediments These sediments are such as to able to absorb large amounts of nutrients and pollutants Consequently the accumulation of sediments starts to fill the basin and increasing the interactions between water and sediments the resuspension of nutrients present at the bottom of the basin is facilitated N Sechi 1986 This phenomenon could in fact lead to a further deterioration of water quality accentuating the processes connected with eutrophication V Tonolli 2001


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