Appendix 1: the Vertical Attenuation of PAR and UVR Was Measured with a Biospherical BIC

Appendix 1: The vertical attenuation of PAR and UVR was measured with a Biospherical BIC compact 4-channel radiometer (Biospherical Instruments, San Diego CA) at three wave lengths [305 nm, 320 nm, 340 nm, and for the entire photosynthetically active radiation spectrum (PAR)]. Vertical attenuation coefficients (K) were determined from the slope of the relationship ln (wavelength (nm) or PAR) as a function on depth.

Lake / KPAR (m-1) / K340 (m-1) / K320 (m-1) / K305 (m-1)
Muskoka / 0.917 /
7.95 / 10.46 / 12.21
Emerald / 0.694 / 5.99 / 9.21 / 13.13
Memorial / 1.58 / 9.44 / 14.51 / 20.50
Lac la Peche / 1.65 / 11.28 / 16.35 / 22.11
Delaronde / 2.60 / 7.4 / 9.9 / 12.9
Constance / 0.393 / 3.30 / 5.68 / 8.90
Brandy / 2.34 / 22.16 / 27.79 / 31.43
Pinkney / 0.677 / 8.29 / 12.43 / 17.35
Turtle / 1.71 / 6.22 / 8.98 / 16.67
Iroquois / 1.09 / 6.45 / 9.44 / 13.36
Little Loon / 1.29 / 8.75 / 12.89 / 17.73
Upper Blackstrap / 2.83 / 7.37 / 9.44 / 11.98
Lower Blackstrap / 2.61 / 7.14 / 9.21 / 11.52
Pelletier / 3.32 / 7.34 / 9.44 / 11.98
Torch / 2.92 / 23.49 / 34.55 / 47.21
Murray / 2.08 / 12.90 / 18.19 / 24.41
Wildlife Pond / 2.05 / 21.53 / 32.86 / 45.60
Cowan / 2.40 / 22.7 / 32.1 / 41.8

Appendix 2: An example of the uptake of radiophosphate (33PO4) by planktonic assemblages. Radiophosphate is injected (time = 0 min). The movement of 33PO4 from the dissolved to the particulate fraction is monitored for ~15 min. A second or third order polynomial is then fit to the data. The uptake constant (k) was determined by taking the derivative of the polynomial function at time zero and dividing by the total radioactivity in each incubation vessel (Currie & Kalf, 1984; Bentzen & Taylor, 1991).