Eco-column Experiment to View How an Ecosystem Functions

Purpose/Hypothesis

The purpose of this lab experiment is to provide the opportunity to view how an ecosystem functions, and how it changes over time. It allows one to observe and assess the properties and various components within the eco-column. The eco-column is set up with an aquatic habitat, decomposition habitat, and a terrestrial habitat. The diverse compartments enable the eco-column to be complete with the necessities of a true ecosystem. As the eco-column transforms over time, it permits a person to analyze a condensed simulation of the process that an actual ecosystem undergoes. The properties that were tested on a weekly basis are the following: odor, turbidity, color, nitrates, dissolved oxygen, alkalinity, pH, temperature, and soil. As the tests are completed and changes are observed from week to week, this allows one to formulate hypotheses and statements. An eco-column is beneficial to students because it is a hands-on and visual construction of an ecosystem. This lab not only provides students with numbers and data, it gives them the opportunity to obtain the data on their own and view firsthand the changes that occur.

Methods

The 2-liter bottles were brought in by the students on September 4^th. The eco-column bottles were cleaned, prepared, and cut according to the directions provided by the teacher. The soil, water, leaf litter, insects, and other supplies were brought in by the students from September 11^th – September 17^th. The eco-column was built and put together according to the directions provided by the teacher on September 17^th. The water was poured into the aquatic chamber, which was the bottom of the eco-column. The soil and leaf litter were placed in the middle compartment of the eco-column. The grass, twigs, and insects were put above the soil compartment. The first tests were completed on September 19^th. The observations were recorded, the properties were recorded, and the soil was prepared for the next test. The second tests were completed on September 24^th. The observations were recorded, the properties were recorded, and the soil from the previous week was tested and recorded. More soil was prepared for the next test. The third tests were recorded on October 1^st. The observations were recorded, the properties were recorded, and the soil from the previous week was tested and recorded. More soil was prepared for the next test. The fourth tests were completed on October 8^th. The observations were recorded, the properties were recorded, and the soil from the previous week was tested and recorded. More soil was prepared for the next test. The fifth tests were recorded on October 22^nd. The observations were recorded, the properties were recorded, and the soil from the previous week was tested and recorded. More soil was prepared for the next test. The sixth, and final, tests were completed on November 5^th. The observations were recorded, the properties were recorded, and the soil from the previous week was tested and recorded. The dissolved oxygen, pH, and turbidity were tested with specialized probes that were dipped into the water. The temperature of the water was taken with a thermometer. The observations of the water were determined by sight and smell. The soil tests were determined by soil samplings mixed with water and specialized powders. The eco-column was broken down on December 3^rd. The eco-column was functioning for 77 days.

Discussion

1. Identify two Food Chains or Food Webs in each of your habitats (chambers). Use arrows to illustrate these food chains and food webs; complete sentences are not required. Use extra paper if needed.

Grass – Crickets – Spiders – Worms

The producer, which is the grass, gets its energy from the sun through photosynthesis. That energy is then transferred to the crickets, which are herbivores. The spiders consume the crickets to gain energy. Finally, the worms break down the spider and renew the nutrients.

Algae – Ants – Praying Mantis – Worms

The producer, which is the algae, gets its energy from the sun through photosynthesis. That energy is then transferred to the ants, which are herbivores. The praying mantises consume the ants to gain energy. Finally, the worms break down the praying mantis and renew the nutrients and energy back into the soil.

2. Identify and briefly discuss the biogeochemical cycles which are taking place/which are present in your EcoColumns. Do not merely state that “they are all present”; instead, provide more specific information.

Water Cycle – It begins in the aquatic habitat. Evaporation causes the water to evaporate to the decomposition habitat. The water gets soaked up in the soil, and then evaporates from there to the terrestrial habitat. It condenses throughout the eco-column, and ultimately trickles back down to the water in the aquatic habitat.

Nitrogen Cycle – Nitrogen goes from the decomposition habitat to the terrestrial habitat. The nitrogen is soaked up by the soil. The nitrogen is then transferred to the insects in the habitat.

3. Is your ecosystem column a closed or open system? — or is it something in between a closed or open system? Explain how this (closed, open or other) influences the ecosystem column overall.

It is an open and closed system. For the majority of the time, it is a closed system because everything is occurring inside the close bottle. But when it is time to take the tests, the hole in the bottle is opened, which allows outside air and nutrients to enter the eco-column. Since it is mostly a closed system, the environment within the eco-column is required to function and stay alive with the cycles and processes it must undergo. With only slight exposure to an open system, it does not have a large impact on the eco-column.

4. What kind of niches are available/present for the various organisms in the column? Be specific, descriptive, and use terminology that is pertinent to the topic.

In the decomposition, the worms and other organisms in there decompose the dead organic matter within the eco-column. They keep the cycle going, and keep nutrients flowing in the eco-column. The algae in the aquatic habitat are responsible for undergoing photosynthesis, which begins the food chain and is necessary for the eco-column to survive. The organisms in the terrestrial habitat are responsible for consuming the leaves and grass, which transfers the energy to the next level.

5. Discuss evidence of ecological succession taking place in your column (or in the column of another lab group if you have not observed any signs of succession in your column).

The water changes color and its qualities change over time. The organisms consume the leaves and grass, which causes there to be more decomposition. There are high amounts of dead matter within the eco-column because everything gets decomposed.

6. Discuss the stability and sustainability of the ecosystem columns in the lab, including your own.

The water temperature stays relatively the same throughout the duration of the lab. Also, the pH does not vary much over time. The potassium and the pH in the soil do not show much change either. The eco-column sustains biodiversity. In our eco-column, the environment was not suitable enough for much biodiversity to be able to survive and grow in the eco-column.

7. Discuss three trends or patterns which stand out as you think back on the data which you have been recording for 6 weeks. These trends or patterns should apply to the water quality tests or other observations which you have made over this multi-week time period. Briefly discuss these three trends or patterns, providing possible explanations based on environmental science principles.

The dissolved oxygen increases overall throughout the duration of the experiment. The water receives more oxygen as time progresses.

The pH only slightly increases throughout the 77-day period. It hovers around the 7-mark, which is neutral.

The turbidity is the quality that undergoes the most drastic changes. It goes from one extreme to the other within just a week.

8. Explain what eutrophication refers to and how this occurs. Apply this explanation to your ecosystem column. How might eutrophication take place in your column? Explain fully.

Eutrophication refers to excessive richness of nutrients in a body of water. Eutrophication mainly occurs from runoff of nutrients in the soil and weathering of rocks. Due to the high amounts of dead organic matter in the soil, eutrophication occurred in my eco-column. The nutrients from the dead organic matter makes its way down to the aquatic habitat, and that causes excessive nutrients to be added into the water.

9. Pick another group in your class. How do your data compare to theirs? Brainstorm some causes/reasons for any differences.

I compared the data of my group to the data of Justin Setzer’s group, and our data was relatively the same. The dissolved oxygen, pH, and temperature of our water shared the same trends and patterns. The soil test results they had were slightly different, which is most likely due to the area in which our groups extracted the soil.

10. Finally, address any sources of error in this lab. This should be narrated in a “cause and effect” manner and talk about specific problems. A good example would be “water did not drain from the terrestrial chamber so …” while a bad example would be “we messed up the measuring one day.”

The soil that we retrieved from the testing we completed on 9/24 was not suitable for testing the next week on 10/1. We did not add enough water to mix in with the soil, so it was difficult to get a good sampling with the pipette without stirring up all the soil.

Conclusion

This lab experiment was quite helpful in expanding my knowledge of ecosystems and what it takes for one to function. I learned that many processes and cycles have to be executed the right way, and without error, for an ecosystem to remain functioning. Determining the water and soil qualities and how they changed over time was imperative to this lab because it allowed one to see how and why they changed. It is important to know that because the qualities can be tested and observed in all bodies of water. The eco-column was very instructional, and it is a great tool for students wanting to broaden their knowledge of ecosystems.

Results

Throughout the table, we observed and tested the various qualities in the water. We tested the water either every week, or every other week. The graph shows the dissolved oxygen, pH, and temperature of the water over time. The dissolved oxygen and pH increased, while the temperature decreased. The dissolved oxygen shows relative exponential growth. The pH shows more of a slight linear growth, while the numbers are within close range with each other. The temperature shows a relatively gradual increase. As time progressed, the temperature dropped. The dissolved oxygen increased because of the progression of the algae in the water. The algae grew, so photosynthesis was able to occur at a higher rate. The pH showed a slight increase because the water switched over the neutral boundary of the pH scale.

References

The Franklin Institute (31 August 2011). Neighborhoods: Ecosystems, Biomes, and Habitats. [ONLINE] Available at: http://www.fi.edu/tfi/units/life/habitat/. [Last Accessed 19 December 2013].

Exploring the Environment (10 November 2004). Water Quality Assessment: Overview. [ONLINE] Available at: http://www.cotf.edu/ete/modules/waterq3/WQassess1.html. [Last Accessed 19 December 2013].

Botkin, D., & Keller, E. (2011). Environmental science: Earth as a living planet. (8^th ed.).

Hoboken, New Jersey : John Wiley & Sons, Inc.