Development of the Athabasca Oil Sands Region (AOSR) has increased atmospheric
nitrogen emissions, a trend which is expected to increase in the future. The area
surrounding development is comprised of Boreal upland forests and peatlands. Improved
understanding of the hydrological connectivity between Boreal peatlands and uplands is
needed to predict the fate and transport of atmospheric N deposited across the region. Two
field sites: Jack Pine High (JPH, located 45 km north of Fort McMurray) and Mariana
Lakes (ML, located 100 km south of Fort McMurray) were instrumented with piezometers
nests and water table wells for this study (n= 108 sampling locations). The wells were
placed along transects that cover target landscape units (bog, fen, upland). Wells were
sampled for water isotopes and geochemical parameters during the summers of 2011-2014
to characterize the baseline geochemistry of groundwater in the different landscape units.
Inorganic (nitrate, ammonium) and organic forms of nitrogen (dissolved organic nitrogen),
major and minor ions and water isotope tracers (18O, 2H and 3H) were measured to
identify the various forms of nitrogen in the different landscape units, as well as to assess
connectivity and potential for nitrogen transport between the different units. At JPH
surface and groundwater flow is from the uplands to the fen. There was little (<0.1-1.5
mg/L) nitrate, ammonium, or dissolved organic nitrate (DON) found throughout JPH. At
ML nitrogen concentrations were higher (<0.1-30 mg/l) and concentrations of ammonium
and DON increased at depths throughout ML. The distribution of 3H with depth within the
peatland reveals limited connectivity between the peat and underlying mineral soils.
Tritium sampling at ML indicates that at some locations the wetland residence time is
greater than 50 years. Nitrogen movement out of peatlands may take longer due to
conversions and storage. At ML nitrogen (NH4 and DON) is produced and stored at depth
in the wetlands. At JPH higher nitrogen concentrations are found in the shallow
groundwater of the fen. Increases in nitrogen inputs to JPH and ML are likely to be utilized
by plants, but dramatic changes to the peatland may cause stored nitrogen to become
mobile. / Graduate
| Identifer | oai:union.ndltd.org:uvic.ca/oai:dspace.library.uvic.ca:1828/7036 |
| Date | 13 January 2016 |
| Creators | Cherry, Mikaela |
| Contributors | Gibson, John J., Birks, S. Jean |
| Source Sets | University of Victoria |
| Language | English, English |
| Detected Language | English |
| Type | Thesis |
| Rights | Available to the World Wide Web |
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