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Investigating variability of biogenic gas dynamics in peat soils using high temporal frequency hydrogeophysical methods
Title
Investigating variability of biogenic gas dynamics in peat soils using high temporal frequency hydrogeophysical methods.
Creator
Wright, William J., Charles E. Schmidt College of Science, Department of Geosciences
Abstract/Description
Peat soils are known to be a significant source of atmospheric greenhouse gasses. However, the releases of methane and carbon dioxide gasses from peat soils are currently not well understood, particularly since the timing of the releases are poorly constrained. Furthermore, most research work performed on peatlands has been focused on temperate to sub-arctic peatlands, while recent works have suggested that gas production rates from low-latitude peat soils are higher than those from colder...
Show morePeat soils are known to be a significant source of atmospheric greenhouse gasses. However, the releases of methane and carbon dioxide gasses from peat soils are currently not well understood, particularly since the timing of the releases are poorly constrained. Furthermore, most research work performed on peatlands has been focused on temperate to sub-arctic peatlands, while recent works have suggested that gas production rates from low-latitude peat soils are higher than those from colder climates. The purpose of the work proposed here is to introduce an autonomous Ground Penetrating Radar (GPR) method for investigating the timing of gas releases from peat soils at the lab scale utilizing samples originating from Maine and the Florida Everglades, and at the field scale in a Maine peatland. Geophysical data are supported by direct gas flux measurements using the flux chamber method enhanced by timelapse photography, and terrestrial LiDAR (TLS) monitoring surface deformation.
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Date Issued
2013
PURL
http://purl.flvc.org/fcla/dt/3361256
Subject Headings
Gas dynamics, Wetland ecology, Soil permeability, Estuarine sediments, Ground penetrating radar, Hydrogeology, Geophysics
Format
Document (PDF)
Biogenic gas dynamics in peat soil blocks using ground penetrating radar: a comparative study in the laboratory between peat soils from the Everglades and from two northern peatlands in Minnesota and Maine
Title
Biogenic gas dynamics in peat soil blocks using ground penetrating radar: a comparative study in the laboratory between peat soils from the Everglades and from two northern peatlands in Minnesota and Maine.
Creator
Cabolova, Anastasija., Charles E. Schmidt College of Science, Department of Physics
Abstract/Description
Peatlands cover a total area of approximately 3 million square kilometers and are one of the largest natural sources of atmospheric methane (CH4) and carbon dioxide (CO2). Most traditional methods used to estimate biogenic gas dynamics are invasive and provide little or no information about lateral distribution of gas. In contrast, Ground Penetrating Radar (GPR) is an emerging technique for non-invasive investigation of gas dynamics in peat soils. This thesis establishes a direct comparison...
Show morePeatlands cover a total area of approximately 3 million square kilometers and are one of the largest natural sources of atmospheric methane (CH4) and carbon dioxide (CO2). Most traditional methods used to estimate biogenic gas dynamics are invasive and provide little or no information about lateral distribution of gas. In contrast, Ground Penetrating Radar (GPR) is an emerging technique for non-invasive investigation of gas dynamics in peat soils. This thesis establishes a direct comparison between gas dynamics (i.e. build-up and release) of four different types of peat soil using GPR. Peat soil blocks were collected at peatlands with contrasting latitudes, including the Everglades, Maine and Minnesota. A unique two-antenna GPR setup was used to monitor biogenic gas buildup and ebullition events over a period of 4.5 months, constraining GPR data with surface deformation measurements and direct CH4 and CO2 concentration measurements. The effect of atmospheric pressure was also investigated. This study has implications for better understanding global gas dynamics and carbon cycling in peat soils and its role in climate change.
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Date Issued
2010
PURL
http://purl.flvc.org/FAU/2974433
Subject Headings
Wetland ecology, Wetland ecology, Wetland ecology, Gas dynamics, Soil permeability, Ground penetrating radar, Porous materials, Fluid dynamics
Format
Document (PDF)
Three-dimensional geomodeling to identify spatial relations between lithostratigraphy and porosity in the karst carbonate biscayne aquifer, southeastern Florida
Title
Three-dimensional geomodeling to identify spatial relations between lithostratigraphy and porosity in the karst carbonate biscayne aquifer, southeastern Florida.
Creator
Westcott, Richard, Root, Tara L., Florida Atlantic University, Charles E. Schmidt College of Science, Department of Geosciences
Abstract/Description
In southeastern Florida, the majority of drinking water comes from the Biscayne aquifer. This aquifer is comprised of heterogeneous limestones, sandstones, sand, shell and clayey sand with zones of very high permeability. Visualizing the spatial variations in lithology, porosity and permeability of heterogeneous aquifers, like the Biscayne, can be difficult using traditional methods of investigation. Using the Roxar IRAP RMS software multi-layered 3D conceptual geomodels of the lithology,...
Show moreIn southeastern Florida, the majority of drinking water comes from the Biscayne aquifer. This aquifer is comprised of heterogeneous limestones, sandstones, sand, shell and clayey sand with zones of very high permeability. Visualizing the spatial variations in lithology, porosity and permeability of heterogeneous aquifers, like the Biscayne, can be difficult using traditional methods of investigation. Using the Roxar IRAP RMS software multi-layered 3D conceptual geomodels of the lithology, cyclostratigraphy and porosity were created in a portion of the Biscayne aquifer. The models were built using published data from borehole geophysical measurements, core samples, and thin sections. Spatial relations between lithology, cyclostratigraphy, porosity, and preferential flow zones were compared and contrasted to better understand how these geologic features were inter-related. The models show local areas of differing porosity within and cross-cutting different cycles and lithologies. Porosity in the Biscayne aquifer study area follows a hierarchy attributed to lithofacies with a pattern of increasing porosity for the high frequency cycles. This modeling improves understanding of the distribution and interconnectedness of preferential flow zones, and is thus an invaluable tool for future studies of groundwater flow and groundwater contamination in the Biscayne aquifer.
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Date Issued
2014
PURL
http://purl.flvc.org/fau/fd/FA00004337, http://purl.flvc.org/fau/fd/FA00004337
Subject Headings
Biscayne Aquifer (Fla.), Geophysics -- Florida -- Miami Dade County, Groundwater flow -- Florida -- Miami Dade County -- Mathematical models, Hydrology, Karst -- Florida -- Miami Dade County, Porosity, Sedimentary basins -- Florida -- Biscayne Aquifer, Sedimentology -- Statistical methods, Soil permeability
Format
Document (PDF)