The Influence of the Mineral Composition of the Medium on the Growth of Planktonic Algae: Part I. Methods and Culture Media

Publisher Website
Google Scholar
Abstract
Fourteen planktonic algae have been maintained in pure culture in flourishing condition for > 2 yrs. in media of composition and degree of dilution comparable with natural waters. The requirements of 6 algae (Pedi-astrum boryanum, Staurastrum paradoxum, Botryococcus braunii, Asterionella gracillima, Fragilaria crotonensis, Nitzschia acicularis and N. palea) were investigated in detail. With few exceptions the algae grew equally well in media supplied with nitrate or with NIL. salts. The most favorable concs. of Ca, Mg, K, Na, SiO2 differ considerably for different algae. The Ca requirement is often lower in media with higher Mg cones., while the presence of excessive K renders the organisms tolerant of higher conc. of Ca and Mg.. No appreciable quantity of SiO2 is necessary except for the diatoms. There is an unfavorable effect on the growth of Pediastrum when the SiO2 conc. exceeds 4 ppm. and on Staurastrum and Botryococcus when it is > 20 ppm. Diatoms are inhibited when the conc. is > 54 ppm. The requirements of N and P agree closely. All algae studied flourish in media with N, 1-7 and P, 0.1-2 ppm. and suffer from deficiency when the conc. of N is < 0.2 and that of P < 0.05 and from an inhibiting effect when the conc. of either exceeds 20 ppm. The optimum range of these concs. is often wider when nitrate is used than when an NH4 salt is the source of N.