Information

Name: Madeleine Martin
Grade Grouping: 10-12
Team Size: 1 member
Subject Area: Environmental Issues
Project Type: Experimental
Language: English
Summary:

A constructed wetland is human-made swamp, fen, bog or marsh built to filter contaminated water flowing from heavily-polluted creeks or rivers to larger water bodies. They have proven very efficient in almost every aspect of water filtration, removing all types of contaminants from sewage to heavy metals. However, there is one disadvantage to such a system. Wetlands emit large concentrations of greenhouse gases, which become trapped in the atmosphere and cause global warming.

The purpose of this experiment was to reduce the amount of methane released from a constructed wetland model by controlling the factors affecting trace gas exchange. While wetlands generally emit methane, carbon dioxide and nitrous oxide, the quantity of methane released is usually much greater than either carbon dioxide or nitrous oxide. The exact amount of each gas released is dependent on several factors affecting the wetland environment. Methane is also a much stronger greenhouse gas than carbon dioxide.

Five wetland models with identical containers, soil types, sphagnum peatmoss concentration were built. 20 Arrowhead (Sagittaria Latifolia) plants were placed in each model. Each of the models were aerated. Water volumes were varied.

After allowing the plants to grow for approximately one month and a half, the models were covered to form airtight chambers, and gas samples were taken using syringes at 0, 10 and 30 minute intervals. The results were analysed on a gas chromatograph at McMaster University.

The results demonstrated that although all the methane fluxes in each of the wetlands were extremely low , the overall Global Warming Potentials of each of the wetlands were affected by other factors, including the health and size of the plants that grew in each model and additional decomposition that took place.

Software Tools: Macromedia Dreamweaver MX 2004, Microsoft Digital Image Pro10
Hardware Tools: Scanner, Digital Camera
Source of Idea: Research
Special Skills: HTML
Awards:

• Silver Medal at the Bay Area Science and Engineering Fair
• Trip to the Canada-Wide Science Fair
• Primary Fluid Systems Earth and Environmental Sciences Award
• Nelson Steel Environmental Award
• Ricoh Sustainable Development Award

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