Physical and chemical limnology of northern boreal lakes, Wood Buffalo National Park, northern Alberta and the Northwest Territories, Canada |
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Authors: | K A Moser J P Smol D R S Lean G M MacDonald |
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Abstract: | Physical and chemical variables were measured in 35 lakes from Wood Buffalo National Park, northern Alberta and the Northwest
Territories, Canada. Of these lakes, 22 were sinkholes, situated on limestone and gypsum, five were situated on the Canadian
Shield and eight were shallow 'muskeg' lakes located on calcareous shales. All of the lakes were small to moderate in size.
For each of the 35 lakes, 37 environmental variables were measured. Principal component analysis (PCA) revealed that underlying
geology strongly influenced limnic properties. Shield lakes were characterized by higher concentrations of A1 and Fe, and
lower pH values, specific conductivities and concentrations of ions such as, Ca, SO4, Li, Mg and Na, than either the sinkhole
or the muskeg lakes. The muskeg lakes were differentiated from the sinkhole lakes by decreased Secchi depth owing to higher
concentrations of dissolved organic carbon (DOC) and greater productivity, as evidenced by high concentrations of particulate
organic carbon (POC) and chlorophyll a. Nitrogen (NH3 and NO2) was also notably higher at these sites.
The 22 sinkhole lakes were further classified by the type of surrounding vegetation. Six vegetation groups were recognized:
(1) spruce; (2) pine; (3) mixed; (4) shrubs/poplar; (5) recently burned and (6) rocky. These vegetation groups largely reflect
fire history, but also differences in soils and drainage. Unlike geology, surrounding vegetation, and therefore recent fire
history, generally had little influence on limnic properties. PCA showed that of the six vegetation groups, only the spruce
lake group, which was characterized by high levels of DIC, was distinct.
This revised version was published online in July 2006 with corrections to the Cover Date. |
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Keywords: | boreal forest limnology subarctic fire lakes principal components analysis |
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