1. Light Attenuation In Water Results From 5 Regional Lakes

2. Light Measurements (LI-COR) Concerned w/ PAR Require both scalar (underwater) and cosine (surface) sensors Units:  mol quanta m - 2 s -1 (  E) Scalar

3. Light Calculations Exponential Decay –Beer’s Law –Compute Ln(I z ) and regress to get slope –Slope = attenuation coefficient, k [m -1 ] Secchi Disk I z = I 0 e - kz

4. Light Attenuation: Wolf Lake k = 0.477 m -1 Secchi: 4.9 m Overcast, rain, windy Pristine but w/ high DOC content

5. Light Attenuation: Arbutis Lake k = 0.891 m -1 Secchi: 2.9 m Heavy cloud cover, slight breeze Slightly more ‘brackish’ than Wolf (visual speaking)

6. Light Attenuation: Green Lake k = 0.174 m -1 Secchi: 8 m Sunny, slight breeze Oligotrophic w/ high CaCO 3 content

7. Light Attenuation: Onondaga Lake k = 0.506 m -1 (?) Secchi: 1.9 m Overcast w/ moderate wind Hypereutrophic (but does have its good days; i.e. clearing)

8. Light Attenuation: Oneida Lake k = 1.20 m -1 Secchi: 2.6 m Conditions unknown (PAR measurements done separately) Eutrophic (and shallow)

9. Light Summary: k, Secchi Drivers: –Wolf/Arbutis: CDOM –Oneida: chlorophyll light measurement and Secchi on different days –Onondaga: low k value doesn’t make sense but… –Green: Beautiful but boring…

10. Questions?