Eutrophication is a natural occurrence over the past centuries as bodies of water age and contains sediment (Carpenter 1981). However, due to human activities, the rate of eutrophication has increased and now plays a big role in fish kills. This happens when inordinate amount of fertilizers flow down the rivers and streams and into the sea, which in turn encourages algae and most, if not all, aquatic plants to overgrow. Fishes will then suffocate due to lack of oxygen and sunlight excessively consumed by algae and aquatic plants. According to Dodds et al, cyanobacteria blooms, contaminated supplies of drinking water, and hypoxia are the known consequences of eutrophication. Chislock, M. F., Doster, E., Zitomer, R. A. & Wilson, A. E. (2013) quoted Lehtiniemi et al (2005), in their article: Eutrophication: Causes, Consequences, and Controls in Aquatic Ecosystems.
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Nature Education Knowledge 4(4):10 about the consequences of eutrophication: “The most noticeable effect of cultural and industrial eutrophication is the production of dense blooms of noxious, unpleasant-smelling phytoplankton that decrease water visibility and degrade water quality. Algal blooms limit light penetration, reducing growth and causing high mortality rates of plants in littoral zones while also reducing the chance of predators from capturing their prey.” In addition, pH levels rise above the normal range of water acidity and dissolved inorganic and organic compounds deplete as a result of high photosynthetic rates caused by eutrophication. The increased pH levels can impair chemosensory abilities of ‘blind’ organisms . The depletion of dissolved oxygen transpires when dense algal blooms die causing microbial decomposition to take place, creating a habitat lacking of oxygen levels called hypoxic or anoxic ‘dead zone’. These hypoxic events usually surround vast, nutrient-rich rivers (e.g. Mississippi River and the Gulf of Mexico; Susquehanna River and the Chesapeake Bay) (Chislock, M. F., Doster, E., Zitomer, R. A. & Wilson, A. E. 2013). In the Environmental Science: A Study of Interrelationships by Enger, E. and Smith, B., a table on the sources and impacts of selected pollutants was made available. One of the pollutants indicated was nutrient enrichment, from agricultural and livestock fields, improper disposal of raw and treated sewage and industrial processes, and phosphate detergents, cause algal blooms. When this large population of algae die off, oxygen levels decline. And as an aftermath: the high mortality rate of fish (2010, p. 347). Fertilizers, sewage, detergent, and animal wastes are sources of chemicals, specifically nitrogen and phosphorus compounds, that promotes excessive growth of aquatic plants and algae. Nutrient enrichment may sound respectable, and it is, but these nutrients should be used with the right amounts and with proper disposal. The nutrient enrichment of water systems doesn’t only affect marine life but also humans. Due to nutrient enrichment, there will be a decreased availability of drinking water; water bills are more expensive for treatment, diseases and even death will happen once nutrient-enriched water is consumed. One of the effects of organic molecules on aquatic ecosystem is fish kills. How can this be? Enger, E. and Smith, B. (2010, pp. 347-348) explains that these organic molecules reduce oxygen levels and reduce numbers and diversity of aquatic life due to its bioaccumulation in individual organisms. If such chemicals persist, they become a significant water pollution problem because of its capability to decompose the water. The naturally present microorganisms in water use up dissolved oxygen to be used for breaking down of organic matter. If too much organic molecules are added into the water, too much oxygen will be consumed, and if too much oxygen is consumed, aquatic organisms die. Toxic chemicals from urban, agricultural, and industrial discharges, and landfills and mines flow to the river and into the ocean. These harmful chemical compounds also enter the ocean via precipitation of atmospheric contaminants (Solomon, E., Berg, L. & Martin, D. 2011. p. 1446). In the early 1970s, the high mortality rate of aquatic life in the bodies of water in Scandinavia, Scotland, northern England, the north eastern United States, and Quebec, Canada was observed. Based on laboratory tests run with the water samples, the cause of the problem was
Nature Education Knowledge 4(4):10 about the consequences of eutrophication: “The most noticeable effect of cultural and industrial eutrophication is the production of dense blooms of noxious, unpleasant-smelling phytoplankton that decrease water visibility and degrade water quality. Algal blooms limit light penetration, reducing growth and causing high mortality rates of plants in littoral zones while also reducing the chance of predators from capturing their prey.” In addition, pH levels rise above the normal range of water acidity and dissolved inorganic and organic compounds deplete as a result of high photosynthetic rates caused by eutrophication. The increased pH levels can impair chemosensory abilities of ‘blind’ organisms . The depletion of dissolved oxygen transpires when dense algal blooms die causing microbial decomposition to take place, creating a habitat lacking of oxygen levels called hypoxic or anoxic ‘dead zone’. These hypoxic events usually surround vast, nutrient-rich rivers (e.g. Mississippi River and the Gulf of Mexico; Susquehanna River and the Chesapeake Bay) (Chislock, M. F., Doster, E., Zitomer, R. A. & Wilson, A. E. 2013). In the Environmental Science: A Study of Interrelationships by Enger, E. and Smith, B., a table on the sources and impacts of selected pollutants was made available. One of the pollutants indicated was nutrient enrichment, from agricultural and livestock fields, improper disposal of raw and treated sewage and industrial processes, and phosphate detergents, cause algal blooms. When this large population of algae die off, oxygen levels decline. And as an aftermath: the high mortality rate of fish (2010, p. 347). Fertilizers, sewage, detergent, and animal wastes are sources of chemicals, specifically nitrogen and phosphorus compounds, that promotes excessive growth of aquatic plants and algae. Nutrient enrichment may sound respectable, and it is, but these nutrients should be used with the right amounts and with proper disposal. The nutrient enrichment of water systems doesn’t only affect marine life but also humans. Due to nutrient enrichment, there will be a decreased availability of drinking water; water bills are more expensive for treatment, diseases and even death will happen once nutrient-enriched water is consumed. One of the effects of organic molecules on aquatic ecosystem is fish kills. How can this be? Enger, E. and Smith, B. (2010, pp. 347-348) explains that these organic molecules reduce oxygen levels and reduce numbers and diversity of aquatic life due to its bioaccumulation in individual organisms. If such chemicals persist, they become a significant water pollution problem because of its capability to decompose the water. The naturally present microorganisms in water use up dissolved oxygen to be used for breaking down of organic matter. If too much organic molecules are added into the water, too much oxygen will be consumed, and if too much oxygen is consumed, aquatic organisms die. Toxic chemicals from urban, agricultural, and industrial discharges, and landfills and mines flow to the river and into the ocean. These harmful chemical compounds also enter the ocean via precipitation of atmospheric contaminants (Solomon, E., Berg, L. & Martin, D. 2011. p. 1446). In the early 1970s, the high mortality rate of aquatic life in the bodies of water in Scandinavia, Scotland, northern England, the north eastern United States, and Quebec, Canada was observed. Based on laboratory tests run with the water samples, the cause of the problem was