EFFECTS OF TEMPERATURE, LIGHT AND SALINITY ON GROWTH IN CULTURE OF CHONDRUS-CRISPUS, FURCELLARIA-LUMBRICALIS, GRACILARIA-TIKVAHIAE (GIGARTINALES, RHODOPHYTA), AND FUCUS-SERRATUS (FUCALES, PHAEOPHYTA)

Growth of Chondrus crispus, Furcellaria lumbricalis, Gracilaria tikvahiae, and Fucus serratus, species common to the Gulf of St. Lawrence, Canada, was studied in unialgal culture. Gracilaria tikvahiae grew best at temperatures of 20° to 25 °C, whereas the remaining three species showed maximum growth at 15 °C. Species were light-saturated for growth at 65 μE m-2 s-1 or below with the exception of F. serratus which required at least 100μEm-2 s-1for saturation. At similar daily total irradiances, longer periods of illumination resulted in increased growth. Salinities commonly encountered in areas of abundance of these species were most favorable for growth, and at < 10 %0 or400/00 > growth was considerably reduced. Gracilaria tikvahiae had the highest relative rate of growth, exceeding that of F. lumbricalis by an order of magnitude; rates for C. crispus and F. serratus were intermediate. © 1979 by Walter de Gruyter & Co.