CS36 Ultraviolet Radiation
Date: Friday, June 14, 2002
Time: 10:30:00 AM
Location: Sidney
 
MooreMV, Wellesley College, Wellesley, MA, USA, mmoore@wellesley.edu
Kohler, S, J, Wellesley College, Wellesley, MA, USA, 
Cheers, M, , Mount Holyoke College, South Hadley, MA, USA, 
 
ARTIFICIAL LIGHT AT NIGHT IN URBAN LAKES
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We obtained the first measurements of artificial light at night at the surface of five lakes located along an urban to rural gradient in New England. Spectra of the artificial light striking urban and suburban lakes were nearly identical and were dominated by yellow light. These spectra closely matched the emission spectrum of high pressure sodium lamps, the most common street lamp in the U.S.A. Incident levels of light intensity at an urban lake were similar to that emitted from a full moon and nearly 50 times greater than that of a rural lake illuminated by starlight only. On average, suburban lakes experienced artificial light intensities 5 - 30 times greater than that of the rural lake. Cloud cover increased incident levels of artificial light two to threefold. The depth to which this artificial light is biologically detectable underwater by crustacean grazers and fish was estimated to range from 1 to 7 meters using vertical extinction coefficients determined for the lakes in conjunction with published limits of light detection by aquatic organisms.