Table 1. Effects of growth parameters on induction of sexual reproduction in T. pseudonana CCMP1335, T. weissflogii and C. cryptica.

Oogonia and auxospores always appeared in stationary phase. The percentage of the total population (at least 300 cells counted per replicate) differentiated into oogonia or auxospores when grown in nitrate or ammonium is shown for the day they were at their maximum number; data are mean values ± s.d., biological replicates n = 3.

Species	Light intensity (μE)	Light regime	Nitrogen concentration (μM)	Specific growth rate (d-1)	Oogonia and auxospores in NO3- (%)	Oogonia and auxospores in NH4+ (%)
T. pseudonana	5	24 h	200	0.28	0.21 ± 0.22	0.52 ± 0.52
	50	24 h	200	0.89	3.67 ± 0.55	7.67 ± 0.50
	50	12 h/12 h L/D	200	0.80	0.67 ± 0.27	2.32 ± 0.52
	220	24 h	200	1.2	0.26 ± 0.26	1.30 ± 0.91
	70	24 h	800	0.98	3.01 ± 0.52	38.9 ± 0.04
C. cryptica	100	24 h	800	0.38	11.1 ± 2.27	37.6 ± 3.71
T. weissflogii	100	24 h	800	0.52	4.50 ± 2.36	39.8 ± 5.65