Discipline: Biological Sciences
Michelle McPherson - Garden City Community College
Co-Author(s): William Friesen, Garden City Community College, Garden City, KS.
The Effects of Acidic Rain on an Environment
The influence of acid rain can be far reaching and influence devastating change in an ecosystem, its effects having been thoroughly describe on terrestrial plants. Here, we explore the effects of acid rain on the ability of aquatic plants to photosynthesize. Some aquatic ecosystems are protected by a carbonate buffer system due to naturally present limestone, thereby mitigating the harmful effects of a lowered pH on the ecosystem. As CO2 is ever on the rise as an atmospheric pollutant, we wondered how acid rain and a limestone-buffered riverbed can influence the ability of a plant to photosynthesize, or absorb gaseous CO2 and fix it into a solid form of carbon. We hypothesized that a limestone-buffered micro-ecosystem would show a greater ability to reduce atmospheric CO2, resulting in higher atmospheric O2 than a similar unbuffered system.
In this experiment, we examined how different types of environments work together in an ecosystem. To mimic the interplay of different environments, we constructed eco-columns consisting of three distinct environments, created by combining five two-liter bottles. The top layer consisted of terrestrial plants, seeds, soil, rocks, and small insects. The second layer, a decomposition layer, included soil, earthworms, leaves, and potato peels. The bottom layer, the aquatic layer, had small photosynthesizing aquatic Elodea plants and rocks. There were four test groups, each conducted in triplicate, consisting of buffered and unbuffered with acid rain exposure and control groups of buffered and unbuffered with clean rain. General observations about the well-being of different organisms were made as well as quantitative measurements of water pH in the aquatic layer, dissolved O2 in aquatic layer, and gaseous CO2 and O2.
As was hypothesized, the unbuffered aquatic environment suffered the most damage from the acidic rain, with the highest pH and lowest levels of dissolved and gaseous O2. The limestone-buffered system fared better than the unbuffered system, with O2 levels and pH comparable to that of the control. From this data, we can conclude that water pH has a direct effect on the ability of aquatic plants to photosynthesize, thereby affecting the quality of life of other aquatic organisms that depend on O2 availability. In the future we hope to continue this project by exploring the effects of herbicide and fertilizer run-off on O2 production.
Funder Acknowledgement(s): Garden City Community College LSAMP-STEM
Faculty Advisor: William Friesen, firstname.lastname@example.org
Role: I constructed an environment using different materials put into different layers that were placed inside of bottles. These models were called Eco-columns. These materials included two liter bottles, terrestrial and aquatic plants, as well as small insects and limestone rocks. After constructing these environments, I added acidic rain to certain Eco-columns and recorded how the environments were affected. I measured the dissolved gaseous O2 and certain pH levels. After recording and reviewing the data I came to a conclusion.