Thorhaug, Anitra , Berlyn, Graeme .
The effect of colored light at various light levels on Zostera marina.
As the intensity of light differs proceeding from intertidal to deeper oceanic water, simultaneously the color of light changes drastically from a broad color spectrum with substantial red light to finally only blue due to seawater and its inclusions creating a spectrum filter. Turbidity in very shallow waters can create much the same color-change effect as does depth. The spectral reflectance and partial absorption responses of the seagrass Zostera marina were studied under a variety of mono-colors while light was diminished during incubations with the red, blue, green and orange collodion filters. The mature plants were exposed for 6 h (morning to mid-day) to randomly varied light intensity and hue. The most notable results occurred at low light intensities during the blue light incubated specimens, which showed intense responses for reflectance and partial absorption between 400 nm and 500 nm for the accessory pigments. Specimens also responded with far less activity in chlorophyll a in the 680 nm area than did those incubated at the same low intensities in either red or orange light. Additionally, the red-light-incubated specimens did not exhibit the same accessory pigment responses as the blue-incubated specimens in the 400 to 500 nm range except at the wavelengths of 450 and 480 nm. The green-light-incubated specimens had variable responses dependent on light intensity, including its green edge response being shifted lower, and clear intense activation of 400 to 500 nm pigments. Orange-light incubation responses appeared similarly to those in red light. Red light exhibited normal red edge effect with less activation in the 400 to 500 nm range especially in the high light incubations. At 23% with blue light the accessory pigment showed peaks of partial absorption and troughs of spectral reflectance within ranges indicating activated carotenoids and xanthophylls.
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1 - Yale University School of Forestry & Environmental Studies, 1359 SW 22 TER, Miami, Florida, 33145, USA
2 - Yale University, School of Forestry and Environmental Studies, Greeley Memorial Laboratory, 370 Prospect Street, New Haven, CT, 06511, USA
Presentation Type: Oral Paper:Papers for BSA Sections
Location: Wasatch B/Cliff Lodge - Level C
Date: Tuesday, July 28th, 2009
Time: 11:00 AM