Figure 3: mean day (red) - night (blue) oxygen consumption (MO2) and standard error for each animal (n=8), oxygen consumption was measured continuously over 3-5 days.
Light conditions: 8am - 8pm light on, 8pm - 8am light off
relative activity MO 2 (µmol O2*h-1*g-1)
relative activity
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- Denton, E.J & Gilpin-Brown, J.B., 1961. The effect of light on the buoyancy of the cuttlefish. J. mar. biol. Ass. U.K., Vol.41, pp 343-350 - Meisel et al.,2003. Circadian rhythms of Octopus vulgaris. Berliner Paläobiol. Abh. , Vol. 3, pp 171-177
- Wells et al., 1983. Diurnal change in activity and metabolic rate in Octopus vulgaris. Mar. Behav. Physiol. , Vol. 9, pp. 275-287 References
MO 2 (µmol O2*h-1*g-1)
Analysis of diurnal activity patterns and related changes in metabolism in the cephalopod
Sepia officinalis
Conclusion
Gilta Jäckel1, Felix C. Mark2, Magdalena Gutowska1, Guy Claireaux, Charlie Ellington2 & Hans O. Pörtner1
Denton and Gilpin-Brown hypothesized in 1961 that the cuttlefish Sepia officinalis displays diurnal changes in activity levels. Other cephalopods perform a diurnal pattern as well (Wells et al 1983, Meisel et al 2003).
We therefore analysed activity patterns of S. officinalis using digital video recordings and analysis. We monitored S. officinalis activity by video continuously for 5 days. In a parallel experiment, we measured oxygen consumption rates in order to see whether metabolic rate changes in parallel with activity levels. We compared both parameters to check the hypothesis of Denton on the one hand and to see how strongly diurnal rhythms influence metabolic rate on the other hand. Values for SMR and AMR estimated from activities and MO2 of both fed and unfed animals depict the influence of food availability and light on diurnal activity patterns of Sepia officinalis.
Activity Oxygen consumption
- clear day-night pattern within - clear day-night pattern for each
each treatment animal
- day activity does not differ between - 30-40% rise in oxygen consumption the treatments, but at night (fig. 3)
- night activity without feeding is nearly - strong response to light-off-effect twice as large as without feeding (fig. 1) (fig. 4)
- both treatments show a response to - SMR = 4,667 µmol O2*h-1*g-1 Fw ± 0,055 light-on- and light-off-effect (fig. 2) AMR = 6,094 µmol O2*h-1*g-1 Fw ± 0,097 - no similar decreases in oxygen consumption and activity curves
Results
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Figure 1: mean day (red) -night (blue) activity and standard error of each treatment; food (n=8, feeding time (5pm), no food (n=8) and low food(n=8, 1 crangon/day for each animal). Light conditions: 8am - 8pm light on, 8pm - 8am light off
Figure 2: mean relative activity per hour and standard error for each treatment; food (blue), no food (red) and low food (green).
- starved Sepia officinalis display a clear diurnal activity pattern. This pattern is also visible in the oxygen consumption, which has already been shown for the cephalopod Octopus vulgaris (Wells et al. 1983)
- feeding in the evening does not influence day-time activity, which is similar to the findings of Wells et al. 1983, too, but it increases night-time activity
- activity depends on light conditions and especially the sunset (light-off-effect) has an important role as "zeitgeber", which differs from O. vulgaris (Meisel et al. 2003) and support the hypothesis that S.officinalis are twilight-feeders
- activity and oxygen consumption do not decrease in parallel, therefore other metabolic processes may be influenced by the diurnal pattern as well, e.g. enzyme activities
relative activity
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Figure 4: Comparison of oxygen consumption and relative activity of starved Sepia officinalis over 24h; mean activity (red) with standard error and mean oxygen consumption (blue) with standard error,
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