Table 2.

Data from C. reinhardtii, G. pectorale and V. carteri populations grown at a light intensity of 600 fc, i.e. experiments described in §§2.2 and 2.3. The format and notation are as in table 1. Additional symbols are the flagellar beating frequency f, the peak flow speed at the equator U (described in §2), the net force that all flagella exert on the fluid F, the propulsion force F_p, the upward swimming speed V_up and the sedimentation speed V_sed. For each measurement on V. carteri, n = 40 colonies were used. For measurements on C. reinhardtii and G. pectorale, n = 120 individuals were used for V_up and V_sed, and n = 4 populations for F_p. Details of the MLR model used here are given in table 4. The average number of somatic cells of a V. carteri colony was 1557 ± 50, and the average number of germ cells was 10.0 ± 0.2. In these experiments, the average number of cells in G. pectorale colonies was 4.1 ± 0.19.

	t2: normal medium	t2: diluted medium	difference between treatments
			absolute	(%)	p-value
C. reinhardtii
Vsed (µm s−1)	6.5 ± 0.24	3.7 ± 0.14	−2.75 ± 0.27	−42.3 ± 4.2	<0.0001
Vup (µm s−1)	43 ± 1.9	54 ± 2.6	11.41 ± 3.32	26.5 ± 7.7	0.0007
Fp (pN)	5.59±0.57	5.13 ± 0.39	§	§	0.5367
G. pectorale
Vsed (µm s−1)	10.0 ± 0.39	8.9 ± 0.37	−1.11 ± 0.54	−11.1 ± 5.4	0.0400
Vup (µm s−1)	33 ± 1.3	37 ± 1.1	4.21 ± 1.76	12.8 ± 5.3	0.0176
Fp (pN)	8.89 ± 0.93	9.06 ± 0.60	§	§	0.8847
V. carteri
R (µm)	144 ± 3.5	174 ± 3.9	27.2 ± 3.32	18.9 ± 2.3	<0.0001
rG (µm)	26.7 ± 0.56	27.1 ± 0.53	§	§	0.6384
rS (µm)	4.63 ± 0.06	4.40 ± 0.05	−0.25 ± 0.07	−5.4 ± 1.5	<0.0001
l (µm)	17.49 ± 0.19	19.49 ± 0.26	0.93 ± 0.25	5.3 ± 1.4	<0.0001
C (cells/103 µm2)	8.93 ± 0.44	6.21 ± 0.29	−2.57 ± 0.34	−28.8 ± 4.0	<0.0001
f (Hz)	27.4 ± 0.27	26.3 ± 0.36	0.66 ± 0.45	2.4 ± 1.6	0.1521
U (µm s−1)	436 ± 11.2	435 ± 9.5	§	§	0.4232
F (pN)	1932 ± 63.6	2157 ± 55.4	211 ± 51	10.9 ± 2.6	<0.0001
Vup (µm s−1)	274 ± 14.5	300 ± 12.3	26 ± 14.4	9.5 ± 5.3	0.0718