The ecosystem of a freshwater lake, stream, and river is greatly influenced by the environment it is in. Temperature, light, nutrients, rainfall amounts, species composition and organic or inorganic pollutant levels all differ from lake to lake, depending on the circumstances of their environment. A change in any one of these factors would have a direct effect on the number of organisms that populate a lake. One way in which the contents of water changes is eutrophication. During this process, organic materials, sediment and nutrients are blown from the surrounding environment into the pond. This in turn increases the nutrient levels in the water. (Bole 56)
[...] Such predictions about these fragile ecosystems have been supported by scientists who study the effects of acidification on freshwater systems. (Lepori) Materials and Methods First, we filled our tanks with two liters of freshwater provided to us. We added an equal amount of detritus to each as well as one snail and one Salvinia plant per tank. We labeled each as either the control or the experimental. The control tank would maintain a constant, normal ph, while the experimental will experience a one ph decrease. [...]
[...] It died on the sixth day, but was slowly deteriorating and its shell weakening. In the experimental tank the Salvinia plant's condition substantially increased, from a five to a six, because of the nutrients the acidified water produced. The control Salvinia's condition decreased, from a five to a two, probably because of the lack of resources available for survival. The fact that the Salvinia's condition improved should not be looked at as a positive sign, it is still an unnatural occurrence and the snail was sacrificed, which disrupts the whole ecosystem. [...]
[...] Results As can be seen in Figure-4, the Salvinia plant in our experimental tank improved in appearance by from a five to a six, but the control dropped by 60% to a 2. Figure-3 shows us that the snail in the experimental died; resulting in a decrease of 100% in its health and a rating of zero and the control snail remained healthy at a four albeit decreasing by 20%. Nutrient quantity fluctuated but generally stayed low in the control and went up in experimental, by the end the experimental was up by 500% to .6 while the control stayed at .2. [...]
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