Sereda, J. M., University of Saskatchewan, Saskatoon, Canada,
Hudson, J. J., University of Saskatchewan, Saskatoon, Canada,
Taylor, W. D., University of Waterloo, Waterloo, Canada,


Our study aimed to assess the impacts of ultraviolet radiation (UVR) exposure on phosphate availability and kinetics within lake planktonic communities. Studies were conducted on three thermally stratified Canadian shield lakes: Muskoka, Brandy, and Plastic. Study lakes were selected to encompass a range of chemical parameters (DOC, TP, pH, Fe) that have been shown to influence aquatic photochemistry. Photochemical changes of UVR exposed lake filtrate (<0.2 ┬Ám) resulted in increased 33P043- turnover times when added back to whole water (Lake Muskoka) relative to controls. However, UV exposed lake filtrate from Brandy and Plastic L. did not have a similar effect. UVR exposed whole water samples from Lake Muskoka and Brandy L. displayed reduced 33P043- turnover times relative to controls. Although photochemical changes were observed in the dissolved organic carbon (DOC) in UVR exposed treatments, these changes did not appear to correspond to increased P bioavailability in these lakes. Our results show that P kinetics in lakes may be influenced through photochemical changes in water chemistry, as well as through direct impacts on planktonic organisms.

Oral presentation

Presentation is given by student: Yes
Session #:SS01
Date: Friday, June 13, 2008
Time: 12:00 PM

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