Quantifying Methane Fluxes over Water in Northeastern PA

The Marcellus Shale, found throughout much of Pennsylvania, has played a key role in driving natural gas production growth in the US. Recently, graduate students studying an area of shale gas development in North-Central Pennsylvania observed methane bubbles and enhanced atmospheric concentrations of methane near a stream in North-Central Pennsylvania. This poses a serious problem to local residents as this CH₄ can enhance the threat of fires from potentially explosive levels of CH₄. Additionally, CH₄ fluxes to the atmosphere from this area are not known, so the threats they pose are also uncertain. This is why it has become crucial to quantify the flux of CH₄ into the atmosphere from sources on land, from the surface of the water, and from under the water. Using the Los Gatos Ultra-Portable Gas Analyzer and High-Density Polyethylene (HDPE) chambers, we tested different ways to find the most efficient method to deploy a flux chamber over water. We eventually developed a chamber design that performed well during leak tests and we were able to use it at our field site in Lycoming County, Pennsylvania where we measured non-zero fluxes across a 90 meter stretch of the stream Sugar Run. These fluxes changed depending on the location in the stream relative to a given seep. The chamber functioned well under these circumstances, but the upper and lower limits of its performance are still unknown.