Publication Date
Fall 2018
Advisor(s) - Committee Chair
Jason S. Polk (Director), John Loughrin, Patricia Kambesis
Degree Program
Department of Geography and Geology
Degree Type
Master of Science
Abstract
Greenhouse gases (GHGs) are a major global environmental concern, because their concentrations have continuously increased over the past few centuries, due to global population growth, fossil fuel dependency, and the Industrial Revolution. Since these gases are naturally occurring phenomena, they will never be completely eliminated. Efforts to reduce them span numerous scientific attempts, with minimal improvements in reducing their atmospheric concentrations. In agricultural land practices, greenhouse gases are common byproducts that affect the atmosphere and, potentially, the groundwater where livestock and fertilizers are key contributors. Little is known about the fate of such greenhouse gases in dissolved form, known as indirect greenhouse gases, especially (CH4 and N2O) in karst landscapes. At Crumps Cave, indirect greenhouse gases were analyzed for seasonal changes along with other geochemistry parameters to identify if anthropogenic land use effected greenhouse gases production in the epikarst and bedrock. This study revealed that CO2 flux is mainly controlled by natural vegetation and seasonal influences. In contrast, CH4 is produced and consumed continuously in the epikarst and bedrock, where decay of organic matter is the primary driver for seasonal change and temperature has little effect on methanogens and methanotrophs survival, because of their ability of adaptation to the environment. N2O, via the nitrogen cycle in which nitrification/denitrification occurs, is directly affected by land use during fertilizer
application and crop rotation. Nitrates from the surface provide a nitrogen source for denitrification to occur and produce elevated N2O in the groundwater system, because residence time is decreased and dissolved oxygen is elevated. Indirect greenhouse gases are linked to karst groundwater systems, where they may be transported and stored in karst aquifers under agricultural land use practices through complex interactions of groundwater recharge, microbial activity, and seasonal land use variability.
Disciplines
Environmental Monitoring | Environmental Sciences | Geochemistry | Geology | Natural Resources and Conservation
Recommended Citation
Antle, Stacy Wayne, "Indirect Greenhouse Gas Dynamics in Karst Groundwater Systems under Agricultural Land Use" (2018). Masters Theses & Specialist Projects. Paper 3082.
https://digitalcommons.wku.edu/theses/3082
Included in
Environmental Monitoring Commons, Geochemistry Commons, Geology Commons, Natural Resources and Conservation Commons