Hi Alex,

Somewhat more stuff about cyanobacteria (which are not common algae but blue algae

Attached to thylakoid membrane, phycobilisomes act as light harvesting antennae for the photosystems. The phycobilisome components (phycobiliproteins) are responsible for the blue-green pigmentation of most cyanobacteria. The variations on this theme are due mainly to carotenoids and phycoerythrins that give the cells the red-brownish coloration.

And yes, in some cyanobacteria, the color of light influences the composition of phycobilisomes. In green light, the cells accumulate more phycoerythrin, whereas in red light they produce more phycocyanin. Thus the bacteria appear green in red light and red in green light. This process is known as complementary chromatic adaptation and is a way for the cells to maximize the use of available light for photosynthesis.

A few genera, however, lack phycobilisomes and have chlorophyll b instead (Prochloron, Prochlorococcus, Prochlorothrix). These were originally grouped together as the prochlorophytes or chloroxybacteria, but appear to have developed in several different lines of cyanobacteria. For this reason they are now considered as part of the cyanobacterial group.

Ther is lots more, but yes, pigmentation is variable in cynaobacteriae according to light spectral composiition and hence in their natural environment their depth in a water body.

Hope this gives some clues for further research.

Cheers,

Frank

Frank, thanks a lot!

Hello Alex,

if you can access an HPLC you can quickly get a very good overview of the pigment composition of the cells. Just run a methanol pigment extraction on e.g. a RP-C18 column in a methanol phase. Hope that helped.

Thank you Martin!