Table 1.

Swimming characteristics of various species of Archaea

Species	Shape (size [μm])	Optimal growth temp (°C)a	Avg velocity (μm/s)b	Maximal velocity (μm/s)	Zigzag movement observed	Velocity in zigzag movement (μm/s)c	Temp range of swimming (°C)	Mode of swimming and/or remarks
Escherichia coli	Rod (2 by 0.7)	37	45 ± 5.0	66	−		20–60	Smooth curves and smooth lines, interrupted by tumbles
Halobacterium salinarum	Rod (10 by 1)	50	3 ± 0.5	10	−		20–65	Slow smooth lines; swimming speed markedly dependent on temp
Methanococcus voltae	Coccus (2)	37	80 ± 8.5	128	+	ND	20–55	Rapid and long notched tracks; shearing has no big influence on swimming capacity
Methanococcus maripaludis	Coccus (1.5)	37	25 ± 3.4	45	+	<10	20–60	Short, notched tracks; extremely sensitive to shearing
Methanocaldococcus jannaschii	Coccus (1.5)	85	380 ± 40	589	+	50–100	20–90	Extremely fast, directional swimming or slower zigzag movement; very slow swimming at room temp
Methanocaldococcus villosus	Coccus (1)	80	287 ± 36	468	+	80–120	50–90	Very fast directional swimming or slower zigzag movement
Pyrococcus furiosus	Coccus (2.5)	100	62 ± 7.0	110	+	30–50	70–95	Swimming markedly dependent on temp; directional swimming and slower zigzag movement
Sulfolobus acidocaldarius	Coccus (1.5)	70	45 ± 4.2	60	−		30–80	Swimming speed markedly dependent on temp; notched tracks with zigzag elements

^aThe data given for average velocity and maximal velocity were determined for this temperature.

^bThe values represent the mean of at least 50 independent swimming tracks from at least 10 cells measured in five independent experiments (see Materials and Methods). The given standard deviation is derived from tracks that differed by not more than 10% from each other. Also included in the standard deviation values are experimental setup-related error sources, like the tracking of diving cells, or problems with program calibration.

^cND, not determined.