PHYCOBILIN CONTENT OF THE CONCHOCELIS PHASE OF ALASKAN PORPHYRA (BANGIALES, RHODOPHYTA) SPECIES: RESPONSES TO ENVIRONMENTAL VARIABLES(1).

Variations of pigment content in the microscopic conchocelis stage of four Alaskan Porphyra species were investigated in response to environmental variables. Conchocelis filaments were cultured under varying conditions of irradiance and nutrient concentrations for up to 60 d at 11� C and 30 psu salinity. Results indicate that conchocelis filaments contain relatively high concentrations of phycobilins under optimal culture conditions. Phycobilin pigment production was significantly affected by irradiance, nutrient concentration, and culture duration. For Porphyra abbottiae V. Krishnam., Porphyra sp., and Porphyra torta V. Krishnam., maximal phycoerythrin (63.2‐95.1 mg AE g dwt )1 ) and phycocyanin (28.8‐64.8 mg AE gd wt )1 ) content generally occurred at 10 lmol photons AE m )2 AE s )1 ,f ⁄4‐f ⁄2 nutrient concentration after 10‐20 d of culture. Whereas for Porphyra hiberna S. C. Lindstrom et K. M. Cole, the highest phycoerythrin (73.3 mg AE g dwt )1 ) and phycocyanin (70.2 mg AE g dwt )1 ) content occurred at 10 lmol photons AE m )2 AE s )1 , f nutrient concentration after 60 d in culture. Under similar conditions, the different species showed significant differences in pigment content. P. abbottiae had higher phycoerythrin content than the other three species, and P. hiberna had the highest phycocyanin content. P. torta had the lowest phycobilin content.