Date of Award
2008
Degree Type
Thesis
Degree Name
Master of Science
Program
Biology
Supervisor
Dr. Irena Creed
Abstract
The average annual temperature measured at the Turkey Lakes Watershed has increased significantly (p=0.004) over the past 27 years. The effects of increasing annual temperatures and changing precipitation patterns on the export of carbon (C) from forests within this region are not fully understood. The aim of this thesis was to determine whether changes in meteorological conditions have caused changes in the magnitude and partitioning of atmospheric vs. aquatic C export form a forested catchment in the Turkey Lakes Watershed during the growing seasons (May 1 to October 31) over a five year period (2003 to 2007). Soil samples were collected and analyzed for the size of the soil organic carbon pool, the sorption capacity of the soils, and the potential saturation of the sorption capacity by dissolved forms of C along an upland-wetland-stream transect. Soil water samples and soil surface carbon dioxide (CO2) efflux were collected throughout the growing seasons on the same transect. Stream water samples were collected along with continuous monitoring of water table depth within the catchment and discharge from the catchment. The major finding was that total C export during the growing season has increased over the five years of sampling, with greater increases observed in atmospheric losses of C as compared to aquatic losses in the form of DOC. The soil C pools and sorption capacity of C within the soils suggests that a major source of carbon that is exported to the stream come from the interface between upland and wetland systems. When the uplands and wetlands are hydrologically connected, DOC is exported. However, when they are hydrologically disconnected, DOC is effectively trapped and subsequently emitted to the atmosphere. The average temperature of the growing season was found to be positively correlated to the magnitude and the partitioning between atmospheric and aquatic export of carbon.
Recommended Citation
Rams, Andrew P., "Shifts in the magnitude and partitioning of atmospheric versus aquatic carbon export in response to changing climatic conditions" (2008). Digitized Theses. 4734.
https://ir.lib.uwo.ca/digitizedtheses/4734