A Diel Periodicity in the Optimum Light Intensity for Maximum Photosynthesis in Natural Phytoplankton Populations

• Published in: Journal of the Fisheries Research Board of Canada
• Main Author: Kalff, J.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1969
• Subjects: General Medicine; Arctic; Phytoplankton
• Online Access: http://dx.doi.org/10.1139/f69-047; http://www.nrcresearchpress.com/doi/pdf/10.1139/f69-047

Diurnally the optimum light intensity for maximum photosynthesis (I max ) of arctic pond phytoplankton was found to change from a high of approximately 0.15 ly/min during the brightest portion of the day to a low of approximately 0.03 ly/min of photosynthetically available illumination when light was minimal. It is suggested that a similarity in the I max need not indicate a similarity in species composition. A maximum efficiency of light utilization (maximum carbon fixed/ly) was found at approximately 0.03 ly/min. A balance between light intensity and efficiency of light utilization determined the I max .