Abstract

Methane (CH4) is a powerful greenhouse gas that has a global warming potential 28 times larger than carbon dioxide (CO2) on a 100-year horizon. Methane emissions from inland freshwater sources are not as well understood as those from other sources; however, current estimates suggest that they account for a significant portion of global CH4 emissions. Emissions from inland waters are difficult to measure due to their high spatiotemporal variability, leading to high levels of uncertainty and a need for more CH4 flux data from these freshwater systems. Increased runoff associated with urbanization has led to construction of man-made inland waters called stormwater ponds. Methane emission estimates for stormwater ponds are very limited and, therefore, are typically not included in the global CH4 budget. In order to reduce uncertainty in the global CH4 budget and to understand how urbanization more fully impacts greenhouse gas emissions, there is a need to characterize CH4 emissions from these ecosystems. The objective of this study was to accurately quantify CH4 emissions from stormwater ponds in Rochester, NY. I hypothesized that high nutrient and sediment inputs in stormwater ponds would support high rates of methanogenesis. Bubble traps were used to quantify ebullitive CH4 flux and floating chambers with shields were used to quantify diffusive CH4 flux. The combined ebullitive and diffusive CH4 flux from June to October averaged 268 mg CH4 m-2 d-1 of which 96% was from ebullition and there was significant variability both seasonally and amongst ponds. July had the greatest ebullitive flux at 386 mg CH4 m-2 d-1 and ebullitive flux varied by 27 times from the highest CH4 emitting pond to the lowest. In addition to temperature driven seasonal patterns, depth and nutrient status were drivers of CH4 emissions from stormwater ponds.

Publication Date

8-4-2021

Document Type

Thesis

Student Type

Graduate

Degree Name

Environmental Science (MS)

Department, Program, or Center

Thomas H. Gosnell School of Life Sciences (COS)

Advisor

Carmody McCalley

Advisor/Committee Member

Anna Christina Tyler

Advisor/Committee Member

Ruth Varner

Campus

RIT – Main Campus

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