<p> <justify> The fish model allows users to see the effects of different concentrations of estrogen on a freshwater ecosystem containing algae, fish, and birds. The model attempts to capture the long-term effects of estrogen on male fish, and demonstrates how sensitive a freshwater ecosystem can be to various concentrations of estrogen. The model is stochastic and it was written in NetLogo, an agent-based modeling language which allows users to view and analyze complex interactions between agents and their environment. A stochastic model employs probability to determine the behavior of its components, thus it is the best type of model to capture the randomness of an ecosystem. The model was also demonstrated to local public school teachers so that they could help their students visualize interactions between different organisms and organisms and their environment. The current lake we are simulating is fictional, however, the code has been developed in such a way that one could substitute the parameters in our model with parameters they have received from a particular lake they wish to test. </justify></p>
<p> <justify> The fish model allows users to see the effects of different concentrations of estrogen on a freshwater ecosystem containing algae, fish, and birds. The model attempts to capture the long-term effects of estrogen on male fish, and demonstrates how sensitive a freshwater ecosystem can be to various concentrations of estrogen. The model is stochastic and it was written in NetLogo, an agent-based modeling language which allows users to view and analyze complex interactions between agents and their environment. A stochastic model employs probability to determine the behavior of its components, thus it is the best type of model to capture the randomness of an ecosystem. The model was also demonstrated to local public school teachers so that they could help their students visualize interactions between different organisms and organisms and their environment. The current lake we are simulating is fictional, however, the code has been developed in such a way that one could substitute the parameters in our model with parameters they have received from a particular lake they wish to test. </justify></p>
If there is no estrogen added, the ecosystem is in dynamic equilibrium. Essentially the ecosystem follows the classic predator prey relationship described in the section titled 'Outline'.</br></br>
If there is no estrogen added, the ecosystem is in dynamic equilibrium. Essentially the ecosystem follows the classic predator prey relationship described in the section titled 'Outline'.</br></br>
Low concentrations of estrogen have a noticeable immediate effect on the ecosystem; however, over time the ecosystem is able to reach dynamic equilibrium once more. At tick 100, 20 ppt of estrogen was added to the water. Around tick 105 the fish population dipped to the lowest value it would ever be (150,000 individuals). This lead to the bird population experiencing a dangerously low dip at around ticks 130-135. Also the low fish population at tick 105, led to the highest recorded algae population around ticks 130-135. </br></br>
Low concentrations of estrogen have a noticeable immediate effect on the ecosystem; however, over time the ecosystem is able to reach dynamic equilibrium once more. At tick 100, 20 ppt of estrogen was added to the water. Around tick 105 the fish population dipped to the lowest value it would ever be (150,000 individuals). This lead to the bird population experiencing a dangerously low dip at around ticks 130-135. Also the low fish population at tick 105, led to the highest recorded algae population around ticks 130-135. </br></br>
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<center><i><b><font size="4">Scenario 3: Medium Estrogen Concentrations (21 – 39 ppt)</center></font></b></i>
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<center><i><b><font size="4">Scenario 3: Medium Estrogen Concentrations (21 – 39 ppt)</font></b></i></br></br>
Medium concentrations of estrogen have quite an interesting effect on the ecosystem. 30 ppt of estrogen was added to the ecosystem at tick 40. From ticks 50-100, the fish population was dangerously low for a longer period of time than a typical dip in the fish population. This long dip in the fish population caused the birds to die out as there was simply not enough food. The long dip in the fish population led to a large spike in the algae population. The spike in the algae population coupled with the local extinction of the bird population, allowed the fish population to boom after its prolonged dip.</br></br>
Medium concentrations of estrogen have quite an interesting effect on the ecosystem. 30 ppt of estrogen was added to the ecosystem at tick 40. From ticks 50-100, the fish population was dangerously low for a longer period of time than a typical dip in the fish population. This long dip in the fish population caused the birds to die out as there was simply not enough food. The long dip in the fish population led to a large spike in the algae population. The spike in the algae population coupled with the local extinction of the bird population, allowed the fish population to boom after its prolonged dip.</br></br>
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<center><i><b><font size="4">Scenario 4: High Estrogen Concentrations (≥ 40 ppt)</center></font></b></i>
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<center><i><b><font size="4">Scenario 4: High Estrogen Concentrations (≥ 40 ppt)</font></b></i></br></br>
When the estrogen concentration is too high, both the fish and bird populations get wiped out. The fish are incapable of producing enough fertile offspring to sustain their population, which in turn means the birds have no available food source. The algae due to the lack of fish, overgrows, and covers the whole lake which leads to other problems such as algal bloom. 60 ppt of estrogen was added at tick 95, and the bird population died almost instantly (~15 ticks), whereas the fish population was a little hardier (died out only after ~100 ticks).
When the estrogen concentration is too high, both the fish and bird populations get wiped out. The fish are incapable of producing enough fertile offspring to sustain their population, which in turn means the birds have no available food source. The algae due to the lack of fish, overgrows, and covers the whole lake which leads to other problems such as algal bloom. 60 ppt of estrogen was added at tick 95, and the bird population died almost instantly (~15 ticks), whereas the fish population was a little hardier (died out only after ~100 ticks).
The fish model allows users to see the effects of different concentrations of estrogen on a freshwater ecosystem containing algae, fish, and birds. The model attempts to capture the long-term effects of estrogen on male fish, and demonstrates how sensitive a freshwater ecosystem can be to various concentrations of estrogen. The model is stochastic and it was written in NetLogo, an agent-based modeling language which allows users to view and analyze complex interactions between agents and their environment. A stochastic model employs probability to determine the behavior of its components, thus it is the best type of model to capture the randomness of an ecosystem. The model was also demonstrated to local public school teachers so that they could help their students visualize interactions between different organisms and organisms and their environment. The current lake we are simulating is fictional, however, the code has been developed in such a way that one could substitute the parameters in our model with parameters they have received from a particular lake they wish to test.
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