Environment entails the total surroundings including both living and nonliving factors. In its total composition, the environment supports both the biotic and abiotic factors in it through provision of nourishment and habitat. Human activities over time continue to ruin the environment through pollution and therefore, a social movement, known as environmentalism advocates for protection and conservation of the environment out of pollution by human kind. In corporation with environmental science in education curriculum, this environmentalism provides knowledge to the people on environmental conservation as it covers both social sciences and hard sciences such as biology, chemistry and ecology. Conservation of environment especially water bodies as lakes help humankind obtain protein supplements in form of fish. However, human activities such as farming lead to pollution of lakes through eutrophication hence drastic decrease in fish population.
Hypothesis from the case study
From the scenario of a farmer who likes fishing but experiences a drastic decrease in the number of fish caught in every fishing venture is a clear indication that there is pollution of the lake from either animal waste or chemical fertilizers. These factors reduce the number of fish in the lake and increase the amount of microscopic plants such as algae in the lake (Clark, Frid, & Attrill, 2001, p.24). Eutrophication is the scientific process in which high nitrogenous animal wastes and fertilizers pollute water bodies leading to excessive growth of algae.
If mineral content in the lake increased due to run off from farms, the amount of algae increased proportionately as nutrients for growth were available. The excessive growth of algae causes oxygen depletion from the water mass consequently leading to reduction in fish population (Pelley, 1998, p.462). Algae assimilate available nutrients especially nitrates and phosphates causing bloom in its growth as shown in the case study.
Eutrophication led to increase in the mineral content in the local lake especially nitrogen and phosphorus either from animal waste or from nitrogenous and phosphate fertilizers applied in the farm in the production of hay for the dairy cattle. Laboratory determination of the mineral content especially of nitrogen and phosphorus from samples of water collected from this polluted lake and comparing the results with samples of water from another lake not polluted or contaminated by animal waste and chemical fertilizers would help in determining the decrease in fish population and the increase in algae. The unpolluted water samples act as the control experiment in determining the level of minerals in the polluted lake (Ball, 2000, p.214). The lakes from which the samples are drawn remain identical and in the same location but one lake remains shielded from agricultural runoffs while the other lake remains exposed to agricultural runoffs.
Quantitative analysis of the mineral content from the two lakes would depict increased amount of mineral levels in the unshielded lake while the shielded lake has its mineral levels remaining constant within a specific period. Comparison of the results obtained from the two experiments shows a significant difference in the mineral contents from the two samples (Dodds, 2002, p.244). In the control experiment, there is no significant decrease in fish population while on the other hand, high mineral levels on the other lake led to increase in algae growth reducing fish population hence the reducing number of fish caught as experienced by the farmer.
Eutrophication of water bodies such as lakes increases the nutrients for microscopic and macroscopic plants like algae to flourish while on the other hand, reducing the population of fish in the lakes affected. High levels of nitrogen and phosphorus content found on the lake water sample taken for quantitative analysis justifies that pollution by agricultural runoffs occurred to the lake leading to excessive growth of algae and the subsequent reduction in the fish population in the lake.
Ball, P. (2000). Life’s Matrix: A Biography of Water. New York: Farrar Straus and Giroux.
Clark, R., Frid, C., & Attrill, M. (2001). Marine Pollution. United Kingdom: Oxford University Press.
Dodds, W. (2002). Freshwater Ecology, Concepts and Environmental Applications. San Diego, CA: Academic Press.
Pelley, J. (1998). Is Coastal Eutrophication out of Control? Environmental Science and Technology, 32(4), 462–466.