I am not say that you can't grow microalgae if they are illuminated 24/7. I just said that it would be unhealthy, the phyto required the most nature habitat you can provided. Lets start with a natural law "everything that is over used is bad from a carrot to exced of exercise" I am analizing what you said and the books part that you used, so if phytoplankton grow good and normally being under lights 24/7 of the 12 months of the year how is possibly that phytoplankton have declined in the world's oceans over the past century in response to ocean warming. When the phytoplankton have abundant sunlight, carbon dioxide and disolved nutrients an undergo explosive growth forming blooms, algal blooms, during these blooms most of the phyto die and sink to the bottom, where descomposes. This process deplets the dissolved oxygen at the water bottom which demaged the culture in no time, in the ocean time this occurs during the springtime.
For confirm what I just wrote you can check on wikipedia: algal bloom; earthobservatory.nasa.gov/NaturalHazards/
There is many reason you don't want to have a wrong amount of light for your phyto the cells will get dense and they would don't feed certains organism like tisbes or rotifers.
In bade the hyphotesis you used, you also can have a look at the following paragraphs on the same book, I just will writte a part!
Appl Microbiol Biotechnol (2011) page 1279; Kimmareddy and Anderson 2004:- In view of the relatives magnitude of aforementioned time scales, the turnover time of the photo-synthetic unit (PSU) or photosyntetic reaction center, is given by the dark reaction time for practical purposes. The light-dark cycle period, which is determined by the travel time of cells between the dark and lit portions along PBR, should accordingly be made AS SHORT AS POSSIBLE, this usually means an optical path of 0.5 to 1.0 cm (to make it clear if the dark time was not necessary then they would mentioned)
Appl Microbiol Biotechnol (2011) page 1279 "Effects of excessively low and high light supply"
"Althought light is required for photosynthesis, too low or high levels thereof will entertain serious disaventantages!! ..."
To who is interesting this pages could be read at
http://www.hcmv.vn.refer.org/moodle/...ic-aspects.pdf
You can have more information on Plakton Culture Manual by Frank H. Hoff & Terry W. Snell.
http://en.m.wikipedia.org/wiki/Phytoplankton
Also you can read it all, but if you just want to be more secure about the light process, look on the last paragraph of Aquaculture.
Just to make it clear, it is always good to try or do different things, for some reason what you suggest didn't work for me on one of the Golden Brown Species of phyto which one required a strong illumination. I am just try to pass on all the information I learned and help any one who is interesting, I have six species of phyto and other live foods and I learn to don't expouse your culture to something that may don't work or you are not 100% sure, but I still respect all the opinion of other people. 16 hours on and 8 hours off it works for me since I start the cultired.