. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. HYPEROXIA AND RESPIRATION IN ANTHOZOANS 151 90 — - 03 Co o o en 6| 60 - 30- Aiptasia pallida 10 9 Time(h) 21 Oxygen level I 50 50-66 kPa Figure 1. Rates of oxygen consumption in Aipui-fiu pn/luhi (n = 5; mean size = mg protein, range = mg protein) under conditions of hypoxia (10% O2 at inflow to respirometer), normoxia (21%O2), and hyperoxia (50% O:). Vertical lines indicate ±1 standard error. Inset: instantaneous heat flux (,(3. /jW) in a specimen (. pallida ( mg protein) exposed to 21%
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. HYPEROXIA AND RESPIRATION IN ANTHOZOANS 151 90 — - 03 Co o o en 6| 60 - 30- Aiptasia pallida 10 9 Time(h) 21 Oxygen level I 50 50-66 kPa Figure 1. Rates of oxygen consumption in Aipui-fiu pn/luhi (n = 5; mean size = mg protein, range = mg protein) under conditions of hypoxia (10% O2 at inflow to respirometer), normoxia (21%O2), and hyperoxia (50% O:). Vertical lines indicate ±1 standard error. Inset: instantaneous heat flux (,(3. /jW) in a specimen (. pallida ( mg protein) exposed to 21% O; and 50%- O2 in an open-flow calorimeter. Figure 4. Two colonies of the ecomorph having thin, widely spaced branches consistently showed a slight ( and ) decrease in respiratory rate under hy- peroxia, whereas three colonies having thick, closely spaced branches showed a mean 20% hyperoxic en- hancement of respiration that was significant (paired / = , df = 2, P = ). The magnitude of the effect of hyperoxia on oxygen consumption in S. pisiillata seems to be inversely related to the hydrodynamic poros- ity of the colony (Fig. 5). Rates of cytochrome c oxidase activity in the various groups ofAiptasia pulchella are shown in Figure 6. Spe- cific activity is expressed in Units per mg protein in the supernatant, each Unit corresponding to 1 ^mol cyto- chrome c oxidized per minute. Analysis of variance indi- cated a significant effect of treatment on enzymatic activ- ity (F= , df = 3, 16. P = ). Individual means were compared using the Student-Newman-Keuls test with a significance level of Discussion The available studies of effects of hyperoxia on the rate of oxygen consumption in fishes and aquatic inverte- brates indicate no enhancement (and perhaps a slight re- duction) of the rate relative to that under normoxia. This is largely due to decreases in the ventilatory convection requirement under hyperoxia (Dejours and Beeken- kamp, 1977; Toul
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