Factors affecting the germination of akinetes of Nodularia spumigena (Cyanobacteriaceae)

Abstract

Nutritional and physical factors which influence the germination of akinetes of Nodularia spumigena (Cyanobacteriaceae) were examined. Low concentrations of phosphorus (< 0.9 μM) were required for germination. Nitrate had no effect, but ammonia, at concentrations of > 45 μM, inhibited germination. Salinities of > 20‰ were inhibitory to germination. Optimum temperatures were 22°C or greater. Germination did not take place in the dark, but only very low intensities (0.5 microeinstein m-2 s-1) were necessary to initiate germination. Red light (620 to 665 nm) was required. More than 24 h of continuous exposure to light was necessary for any significant germination to occur. The conditions for germination correspond with conditions in the Peel-Harvey Estuary, Western Australia, 2 to 3 weeks before large summer Nodularia blooms.