Abstract
The effects of diurnal variations in light intensity on the biomass characteristics and the efficiency of daily growth of Skeletonema costatum (Grev.) Cleve were evaluated. The relative importance of changes in carbon specific rates of respiration and organic release to the efficiency of growth was determined. Light intensity was either constant at 130 μE · m −2 · s −1 during the light period or fluctuated throughout the light period from 500 to 10 μE · m −2 · s −1 at rates of either 1 or 12 cycles · day −1. Total daily light was equivalent for all light regimes at 5.6 E · m −2 · day −1. Daily rates of growth remained comparable at ≈ 1 · day −1 under constant and fluctuating light regimes. Cell size as daily mean carbon · cell −1, nitrogen · cell −1 and cellular volume was decreased under diurnally varying light whereas daily mean chlorophyll a · cell −1 was unaffected. Rates of respiration, organic release and gross production were elevated several fold under diurnally varying light in comparison to constant light. Net growth efficiency decreased from 0.69 under constant light to values of 0.50 and 0.38 under 1 and 12 cycles · day −1, respectively. Decreased efficiency of growth under diurnally fluctuating light resulted mostly from greater respiratory activity while organic release remained < 10% of gross production. Increased rates of gross production reflected enhancement in the efficiency of carbon fixation with fluctuating light.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
More From: Journal of Experimental Marine Biology and Ecology
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.