Using Hydrogeophysical Methods for Investigating Carbon Dynamics in the Greater Everglades Watershed: Implications for the Spatial and Temporal Variability in Carbon Stocks and Biogenic Gas Fluxes

• Other Authors: McClellan, Matthew D. (author), Comas, Xavier (Thesis advisor), Florida Atlantic University (Degree grantor), Charles E. Schmidt College of Science, Department of Geosciences
• Format: Thesis
• Language: English
• Published: Florida Atlantic University
• Subjects: Greenhouse gases; Everglades (Fla.); Peatlands; Carbon; Bogenic gas; Subarctic
• Online Access: http://purl.flvc.org/fau/fd/FA00013238; https://fau.digital.flvc.org/islandora/object/fau%3A41378/datastream/TN/view/Using%20Hydrogeophysical%20Methods%20for%20Investigating%20Carbon%20Dynamics%20in%20the%20Greater%20Everglades%20Watershed%3A%20Implications%20for%20the%20Spatial%20and%20Temporal%20Variability%20in%20Carbon%20Stocks%20and%20Biogenic%20Gas%20Fluxes.jpg

Peat soils store a large fraction of the global soil carbon (C) pool and comprise 95% of wetland C stocks. They also have the capability to produce and release significant amounts of greenhouse gasses (CO2, CH4) into the atmosphere. Most studies of wetland soil C and gas flux dynamics have been done in expansive peatlands in northern boreal and subarctic biomes. However, wetlands in temperate and tropical climates are vastly understudied despite accounting for more than 20% of the global peatland C stock and storing large amounts of biogenic gasses Although studies investigating greenhouse gas dynamics from peatlands have increased during the last decade, the spatial and temporal distribution of these gases still remains highly uncertain, mainly due to the limitations in terms of spatial and temporal resolution and invasive nature of most methods traditionally used. This thesis combines a series of field and laboratory studies at several sites in the Greater Everglades as examples to show the potential of hydrogeophysical methods to better understand: 1) the belowground C distribution and overall contribution to the global C stocks of certain wetlands (Chapter 2); and 2) the spatial and temporal variability in both C accumulation and releases from peat soil monoliths from several wetland sites in the Greater Everglades (Chapter 3 and 4). To estimate belowground C in the field, I used a combination of indirect non-invasive geophysical methods (GPR), aerial imagery, and direct measurements (coring) to estimate the contribution of subtropical depressional wetlands to the total C stock of pine flatwoods landscape at the Disney Wilderness Preserve (DWP, Orlando, FL). Three-dimensional (3D) GPR surveys were used to define the thickness of stratigraphic layers from the wetland surface to the mineral soil interface within depressional wetlands. Depth-profile cores in conjunction with C core analysis were utilized to visually confirm depths of each interface and estimate changes in soil C content with depth and were ...